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Kyung Hee University is a private, research university encompassing an educational system from kindergarten to graduate school with campuses in Seoul, Suwon, and Gwangneung , South Korea. Kyung Hee has 24 colleges, 71 departments and majors, 65 master's and 63 doctorate programs, 18 professional and special graduate schools, and 43 auxiliary research institutions. The university counts Jason Barker and Slavoj Žižek among its renowned international professors.The university celebrated its sixtieth anniversary in 2009. In 1993 Kyung Hee received the UNESCO Prize for Peace Education. In 2006, Kyung Hee and the University of Pennsylvania initiated the Penn-Kyung Hee Collaborative Summer Program and two years later a formal Global Collaborative with Peking, Ritsumeikan, and Moscow State universities; the United Nations Department of Economic and Social Affairs; and the Conference of NGOs . Kyung Hee's interdisciplinary bio-medical cluster maintains one of the world's leading research programs for the study of oriental medicine and its application to contemporary medical treatment in tandem with Western approaches, including the world's first successful drug-free acupunctural anesthesia demonstration in 1972. As of 2011 Kyung Hee University maintains sister relationships with 402 universities in 68 countries.Kyung Hee was founded in 1949 by Dr. Young Seek Choue, whose founding philosophy was "Toward a New Civilization." The university hosted the 1968 conference of the International Association of University Presidents, first proposed in 1981 the UN International Day of Peace, organized the 1999 Seoul International Conference of NGOs, held the 2009 World Civic Forum, ran the 2011 UNAI-Kyung Hee International Symposium, and has spearheaded the Global Common Society movement. Wikipedia.

Siddiqi M.H.,Kyung Hee University
Sensors (Basel, Switzerland) | Year: 2013

Over the last decade, human facial expressions recognition (FER) has emerged as an important research area. Several factors make FER a challenging research problem. These include varying light conditions in training and test images; need for automatic and accurate face detection before feature extraction; and high similarity among different expressions that makes it difficult to distinguish these expressions with a high accuracy. This work implements a hierarchical linear discriminant analysis-based facial expressions recognition (HL-FER) system to tackle these problems. Unlike the previous systems, the HL-FER uses a pre-processing step to eliminate light effects, incorporates a new automatic face detection scheme, employs methods to extract both global and local features, and utilizes a HL-FER to overcome the problem of high similarity among different expressions. Unlike most of the previous works that were evaluated using a single dataset, the performance of the HL-FER is assessed using three publicly available datasets under three different experimental settings: n-fold cross validation based on subjects for each dataset separately; n-fold cross validation rule based on datasets; and, finally, a last set of experiments to assess the effectiveness of each module of the HL-FER separately. Weighted average recognition accuracy of 98.7% across three different datasets, using three classifiers, indicates the success of employing the HL-FER for human FER.

Pode R.,Kyung Hee University
Advanced Materials Letters | Year: 2011

The open circuit voltage (VOC) plays a crucial role in determining the efficiency of organic solar cells. Models ofthe VOC based on (i) the energy difference between the LUMO of the acceptor material and the HOMO of the donor material at the heterointerface and (ii) chemical potential gradient which depends on the carrier mobility in a bilayer cell, areinadequate to understand the exact origin of the VOC. In this review article, the VOC in various planar and non-planar metal phthalocyanine/C60 solar cells are analyzed. These results are compared in CuPc/C60 and SubPc/C60 solar cells as a representative case of the planar and non-planar metal phthalocyanine/C60 solar cells, respectively. Regardless of unfavorable characteristics of SubPc films, the VOC value of 0.92 to 0.98V in SubPc (13 nm)/C60 (33 - 32.5 nm) compared to 0.44 to 0.49V in CuPc (20 - 40 nm)/C60 (40 - 30 nm) solar cells was noticed. It is suggested that the structure, morphology, and absorption properties of the evaporated film of the donor materials and the efficient separation of charges at the donor/acceptor interface in bilayer planar and non-planar metal phthalocyanine/C60 solar cells are also imperative in determining the VOC. © 2011 VBRI press.

Kang D.,Kyung Hee University | Kang D.,University of Suwon | Lansey K.,University of Arizona
Journal of Water Resources Planning and Management | Year: 2014

Long-range infrastructure planning is fraught with uncertainties. Population growth may occur faster or slower than expected, regulations may change, and public sentiment can shift. In the face of these uncertainties, water system managers must plan for large infrastructure investments and the questions about when it is desirable to invest in infrastructure and what is the appropriate infrastructure component size to meet growing demands. One of the most powerful and intuitive ways to incorporate uncertainties is to use scenarios that represent plausible futures. Scenario-based planning is gaining acceptance in the water resources community. Preparing for a range of possible futures provides flexibility and adds robustness to the system so it can respond to uncertain events at reasonable costs while maintaining community confidence in their utilities. In this paper, novel scenario-based planning and optimization approaches are presented for the optimal design of regional-scale water supply infrastructure in a multiperiod planning framework. For demonstration, water demand projections are considered as uncertain and multiperiod construction projects are selected to minimize the economic costs. The solution approaches are applied to a decentralized water reclamation planning project in a green-field development area in southeast Tucson, Arizona, where water reclamation is viewed as a potential component for a sustainable water supply. © 2014 American Society of Civil Engineers.

Kang D.,Kyung Hee University | Kang D.,University of Suwon | Lansey K.,University of Arizona
Journal of Water Resources Planning and Management | Year: 2014

This paper presents a data-driven simulation-based burst detection approach in water distribution systems using control limit analysis. System specific burst sensitivity tables are developed by synthetically generating burst events and analyzing the system hydraulic responses to the given bursts. Potential locations of pressure and flow meters are suggested based on the sensitivity tables. By matching the field observation data with the developed burst sensitivity tables, potential burst hotspots are identified. Using simulated bursts for a simple literature network, it was found that the proposed approach is effective to quickly locate bursts and reduce response times. © 2014 American Society of Civil Engineers.

Lim S.D.,Kangwon National University | Lee C.,Kyung Hee University | Jang C.S.,Kangwon National University
Plant, Cell and Environment | Year: 2014

Plant growth under low water availability adversely affects many key processes with morphological, physiological, biochemical and molecular consequences. Here, we found that a rice gene, OsCTR1, encoding the RING Ub E3 ligase plays an important role in drought tolerance. OsCTR1 was highly expressed in response to dehydration treatment and defense-related phytohormones, and its encoded protein was localized in both the chloroplasts and the cytosol. Intriguingly, the OsCTR1 protein was found predominantly targeted to the cytosol when rice protoplasts transfected with OsCTR1 were treated with abscisic acid (ABA). Several interacting partners were identified, which were mainly targeted to the chloroplasts, and interactions with OsCTR1 were confirmed by using biomolecular fluorescence complementation (BiFC). Interestingly, two chloroplast-localized proteins (OsCP12 and OsRP1) interacted with OsCTR1 in the cytosol, and ubiquitination by OsCTR1 led to protein degradation via the Ub 26S proteasome. Heterogeneous overexpression of OsCTR1 in Arabidopsis exhibited hypersensitive phenotypes with respect to ABA-responsive seed germination, seedling growth and stomatal closure. The ABA-sensitive transgenic plants also showed improvement in their tolerance against severe water deficits. Taken together, our findings lend support to the hypothesis that the molecular functions of OsCTR1 are related to tolerance to water-deficit stress via ABA-dependent regulation and related systems. © 2013 John Wiley & Sons Ltd.

This study numerically examines three-dimensional liquid metal (LM) magnetohydrody-namic (MHD) flows in a rectangular, electrically-conducting duct with sudden contraction in a direction perpendicular to a uniform magnetic field. Though diverse analytical, experimental and numerical studies on MHD duct flows are performed, reports dealing with detailed flow characteristics of LM MHD flows in a rectangular duct with sudden contraction in a direction perpendicular to a uniform magnetic field are hardly found. In the present study, with the use of commercial software CFX code, the flow velocity, pressure, Lorentz force, current and electric potential in the MHD duct flow are obtained for flows with two different Hartmann numbers (1000 and 300) with fixed Reynolds number. The interdependency of the flow variables is considered in the discussion of the MHD duct flows with sudden contraction. The results show that large-scaled loops of the current passing through the duct walls and fluid region are created in the LM MHD flow, where the forward-facing wall serves as the path of the returning current that is induced in the fluid region. © 2014 Elsevier Ltd.

Kim J.E.,Kyung Hee University
Journal of the Korean Physical Society | Year: 2014

Democracy among the same type of particles is a useful paradigm in studying masses and interactions of particles with supersymmetry (SUSY) or without SUSY. This simple idea predicts the presence of massless particles. We attempt to use one of these massless pseudoscalar particles to generate the cosmological dark energy (DE) potential. To achieve the extremely shallow potential of DE, we require the pseudoscalar boson not couple to quantum chromodynamics (QCD) anomaly. Thus, we consider two pseudoscalars, one coupling to the QCD anomaly (i.e., the QCD axion) and the other not coupling to the QCD anomaly. To obtain these two pseudoscalars, we introduce two approximate global U(1) symmetries to realize them as the pseudo-Goldstone bosons of the spontaneously broken U(1) symmetries. These global symmetries are dictated by a gravity-respecting discrete symmetry. Specifically, we consider an S 2(L) × S 2(R) × Z 10R example and attempt to obtain the DE scale in terms of two observed fundamental mass scales, the grand unification scale M G and the electroweak scale υ ew. © 2014 The Korean Physical Society.

Kang M.,Kyung Hee University | Im T.,Florida State University
Journal of Computer Assisted Learning | Year: 2013

Interaction in the online learning environment has been regarded as one of the most critical elements that affect learning outcomes. This study examined what factors in learner-instructor interaction can predict the learner's outcomes in the online learning environment. Learners in K Online University participated by answering the survey, and data from 654 respondents were analysed for this study. Results showed that factors related to instructional interaction predicted perceived learning achievement and satisfaction better than factors related to social interaction. However, it was revealed that social interaction such as social intimacy could negatively affect perceived learning achievement and satisfaction. This study has value because it found factors under learner-instructor interaction which predict perceived learning achievement and satisfaction with empirical evidence. © 2013 Blackwell Publishing Ltd.

Ma H.,University of Tennessee at Knoxville | Li H.,Kyung Hee University
IEEE Transactions on Smart Grid | Year: 2013

The oscillation of frequency in power grid is studied in this paper. The possibility association of frequencies measured at different locations are modeled by a Bayesian network with the logical structure learned using Bayesian structure learning and real measurements in the U.S. power grid. Frequency data analysis and the detection of incorrect frequency measurements (caused by equipment error or malicious attack) are performed over the logical Bayesian network structure. Such application of Bayesian network is a powerful mathematical tool in computational intelligence. Without the physical power network topology information, a two-branch search-and-score structure learning algorithm with L -1 regulation is proposed to learn the logical structure, achieving around 97% correct prediction rate for future frequency and 92% detection rate for false frequency data with 2% false alarm rate. The tool of epidemic propagation over this logical network is also exploited to analyze the propagation of frequency changes. Using the Kolmogorov-Smirnov test, such logical structure is demonstrated to be well approximated by the Small World network model. And the propagation of frequency changes is demonstrated to be described by the Susceptible-Infectious-Susceptible (SIS) model quite well. The Bayesian structure obtained from the real measurement is statistically validated using a 5-fold training data and the Pearson system. © 2012 IEEE.

Song K.-D.,Korea University | Kempa T.J.,Harvard University | Park H.-G.,Korea University | Kim S.-K.,Kyung Hee University
Optics Express | Year: 2014

We studied optical resonances in laterally oriented Si nanowire arrays by conducting finite-difference time-domain simulations. Localized Fabry-Perot and whispering-gallery modes are supported within the cross section of each nanowire in the array and result in broadband light absorption. Comparison of a nanowire array with a single nanowire shows that the current density (JSC) is preserved for a range of nanowire morphologies. The JSC of a nanowire array depends on the spacing of its constituent nanowires, which indicates that both diffraction and optical antenna effects contribute to light absorption. Furthermore, a vertically stacked nanowire array exhibits significantly enhanced light absorption because of the emergence of coupled cavity-waveguide modes and the mitigation of a screening effect. With the assumption of unity internal quantum efficiency, the JSC of an 800-nm-thick cross-stacked nanowire array is 14.0 mA/cm2, which yields a ~60% enhancement compared with an equivalent bulk film absorber. These numerical results underpin a rational design strategy for ultrathin solar absorbers based on assembled nanowire cavities. © 2014 Optical Society of America.

Kim Y.H.,Kyung Hee University | Stormont M.,University of Missouri
Journal of Positive Behavior Interventions | Year: 2012

This study was an exploratory study of 34 South Korean early childhood educators' strategies for addressing behavior problems in natural settings. Factors related to teachers' strategy implementation were also explored. Four specific teacher behaviors were observed: precorrection, behavioral-specific praise, redirection, and reprimand/punishment. Among the four types of behaviors, redirection was most frequently implemented and behavioral-specific praise was least frequently implemented. Children taught by teachers with higher education levels and stronger beliefs in developmentally appropriate practices displayed lower levels of behavior problems. Teachers' developmentally inappropriate beliefs and severity of behavior problems of children were associated with teachers' use of reprimands. Implications of these findings and limitations of the study are discussed. © 2012 Hammill Institute on Disabilities.

Choi E.M.,Kyung Hee University
Food and Chemical Toxicology | Year: 2011

Kaempferol, a natural flavonoid present in fruits, vegetables, and teas, provides beneficial effects for human health. In this study, we investigated the protective effects of kaempferol on antimycin A (AMA)-induced toxicity in osteoblast-like MC3T3-E1 cells. Exposure of MC3T3-E1 cells to AMA caused significant cell viability loss, as well as mitochondrial membrane potential dissipation, complex IV inactivation, intracellular calcium ([Ca2+]i) elevation, and reactive oxygen species (ROS) production. Pretreatment with kaempferol prior to AMA exposure significantly reduced AMA-induced cell damage by preventing mitochondrial membrane potential dissipation, complex IV inactivation, [Ca2+]i elevation, and ROS production. Kaempferol also induced the activation of PI3K (phosphoinositide 3-kinase), Akt (protein kinase B), and CREB (cAMP-response element-binding protein) inhibited by AMA, which result demonstrates that kaempferol utilizes the PI3K/Akt/CREB pathway to augment metabolic activity inhibited by AMA. All these data indicate that kaempferol may reduce or prevent osteoblasts degeneration in osteoporosis or other degenerative disorders. © 2011 Elsevier Ltd.

Kim J.,Kyung Hee University
Nutrition Research and Practice | Year: 2013

Zinc may participate in blood pressure regulation and in the pathogenesis of hypertension. The study examined the relationship between zinc status and blood pressure in obese Korean women. Forty obese women (body mass index (BMI) ≥ 25 kg/m2) aged 19-28 years participated in this study. Zinc intake was estimated from one 24 hour recall and 2-day diet records. Serum and urinary zinc concentrations were determined by atomic absorbance spectrophotometry. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured using an automatic sphygmometer. Metabolic variables, such as waist circumference, triglyceride, high density lipoprotein (HDL) cholesterol, fasting glucose, and fasting insulin, were also measured. Dietary zinc intake of obese women was averagely 7.5 mg/day. Serum zinc and urinary zinc concentrations were 13.4 μmol/L and 378.7 μg/day, respectively. Averages of SBP and DBP were 119 mmHg and 78 mmHg. Dietary zinc intake was negatively correlated with SBP after adjusting for energy intake (P < 0.05), but serum and urinary zinc concentrations were not found to be correlated with SBP or DBP. Multivariate linear regression analysis showed that dietary zinc intake was inversely associated with SBP in obese women after adjusting for body weight, energy intake and sodium intake (P = 0.0145). The results show that dietary zinc intake may be an independent risk factor of elevated SBP in obese Korean women. © 2013 The Korean Nutrition Society and the Korean Society of Community Nutrition.

You Y.,Kyung Hee University | Cho S.,Ewha Womans University | Nam W.,Ewha Womans University
Inorganic Chemistry | Year: 2014

Phosphorescence signaling provides a valuable alternative to conventional bioimaging based on fluorescence. The benefits of using phosphorescent molecules include improved sensitivity and capabilities for effective elimination of background signals by time-gated acquisition. Cyclometalated Ir(III) complexes are promising candidates for facilitating phosphorescent bioimaging because they provide synthetic versatility and excellent phosphorescence properties. In this Forum Article, we present our recent studies on the development of phosphorescence sensors for the detection of metal ions based on cyclometalated iridium(III) complexes. The constructs contained cyclometalating (C^N) ligands with the electron densities and band-gap energies of the C^N ligand structures systematically varied. Receptors that chelated zinc, cupric, and chromium ions were tethered to the ligands to create phosphorescence sensors. The alterations in the C^N ligand structures had a profound influence on the phosphorescence responses to metal ions. Mechanistic studies suggested that the phosphorescence responses could be explained on the basis of the modulation of photoinduced electron transfer (PeT) from the receptor to the photoexcited iridium species. The PeT behaviors strictly adhered to the Rehm-Weller principle, and the occurrence of PeT was located in the Marcus-normal region. It is thus anticipated that improved responses will be obtainable by increasing the excited-state reduction potential of the iridium(III) complexes. Femtosecond transient absorption experiments provided evidence for the presence of an additional photophysical mechanism that involved metal-ion-induced alteration of the intraligand charge-transfer (ILCT) transition state. Utility of the mechanism by PeT and ILCT has been demonstrated for the phosphorescence sensing of biologically important transition-metal ions. In particular, the phosphorescence zinc sensor could report the presence of intracellular zinc pools by using confocal laser scanning microscopy and photoluminescence lifetime imaging microscopy techniques. We hope that the significant knowledge gained from our studies will be of great help in the design of new molecules as phosphorescence sensors. © 2013 American Chemical Society.

You Y.,Kyung Hee University | Nam W.,Ewha Womans University
Chemical Science | Year: 2014

Metabolism of molecular oxygen in the human body inevitably produces reactive oxygen species (ROS). Among the family of ROS, those exhibiting very high reactivities, including OH, OOH, ONOO-, HOCl, HOBr, and 1O2, remain relatively underexplored. While emerging evidence suggests that these ROS are critically involved in physiological function as well as the genesis and development of diseases, the scarcity of the knowledge about these species hampers full understanding of the pathophysiology caused by the oxidative metabolism. To unveil the molecular mechanisms of the ROS, photoluminescent probes capable of reporting identity, concentration, and trafficking of the individual class of the ROS are in great demand. In this Perspective, we focus on 1O2and OH and summarize the known principles for designing photoluminescent molecular probes for these species. Special emphasis is placed on molecular design to selectively detect 1O2and OH. Disadvantages and limitations of using the established probes for detection of biological 1O2and OH are discussed as well. Finally, we address the importance of metal-oxygen species, such as iron-oxygen complexes of peroxo, superoxo, and oxo ligands, in oxidative processes and modulation of ROS. Despite the fact that the very high reactivity of the metal-oxygen species is recognized to be a key factor in many oxidative metabolic pathways, strategies for rational design of photoluminescent probes for detection of these species have yet to be established. As an initial step, we summarize the reactivities of the iron-oxygen species and propose potential approaches for creation of fluorescent molecular probes in the future. The principles provided in this Perspective will be helpful for designing photoluminescent ROS probes capable of applications in the biological milieu. This journal is © the Partner Organisations 2014.

Yoon P.H.,University of Maryland University College | Yoon P.H.,Kyung Hee University
Journal of Geophysical Research A: Space Physics | Year: 2015

Spacecraft measurements of charged particles in the solar wind show that their velocity distributions deviate from thermal Maxwellian model, having energetic components with quasi-scale-free power law velocity dependence, f μ v-α, in the high-velocity range. It is customary to model such a feature by means of the kappa distribution, first introduced in the 1960s to empirically fit the data, but attempts have been made to understand the kappa distribution in terms of nonextensive statistical mechanics. A recent series of papers explore an alternative model, which may be interrelated with the nonextensive thermostatistical concept. According to the model, the electron kappa distribution is understood as a self-consistent steady state solution of the weak turbulence equation in which the electrons and electrostatic Langmuir turbulence are in dynamic equilibrium state. These papers also compared the theoretical kappa parameter with observations of quiet time solar wind electrons near 1 AU. However, the electrostatic Langmuir turbulence, also known as the quasi-thermal noise, requires a more in-depth analysis. The present paper extends the recent theory by including a discussion of electrostatic fluctuations in greater detail, thus bringing the theory to a full closure. Key Points Electron kappa VDF is asymptotic state of weak turbulenceThe associated quasi-thermal noise spectrum is calculatedComparison with observation is excellent ©2014. American Geophysical Union. All Rights Reserved.

Choi S.C.,Kyung Hee University
Quintessence international (Berlin, Germany : 1985) | Year: 2011

Surgical repositioning is a treatment option for an impacted tooth with root dilaceration in an inverted position. In this case report, surgical repositioning of an abnormally impacted and labially dilacerated maxillary right central incisor is described. The impacted and dilacerated maxillary incisor was surgically repositioned in the early root development period and erupted into proper position with normal root development during a 2-year follow-up period.

Lin R.P.,University of California at Berkeley | Lin R.P.,Kyung Hee University
Space Science Reviews | Year: 2011

RHESSI measurements relevant to the fundamental processes of energy release and particle acceleration in flares are summarized. RHESSI's precise measurements of hard X-ray continuum spectra enable model-independent deconvolution to obtain the parent electron spectrum. Taking into account the effects of albedo, these show that the low energy cut-off to the electron power-law spectrum is typically ≲tens of keV, confirming that the accelerated electrons contain a large fraction of the energy released in flares. RHESSI has detected a high coronal hard X-ray source that is filled with accelerated electrons whose energy density is comparable to the magnetic-field energy density. This suggests an efficient conversion of energy, previously stored in the magnetic field, into the bulk acceleration of electrons. A new, collisionless (Hall) magnetic reconnection process has been identified through theory and simulations, and directly observed in space and in the laboratory; it should occur in the solar corona as well, with a reconnection rate fast enough for the energy release in flares. The reconnection process could result in the formation of multiple elongated magnetic islands, that then collapse to bulk-accelerate the electrons, rapidly enough to produce the observed hard X-ray emissions. RHESSI's pioneering γ-ray line imaging of energetic ions, revealing footpoints straddling a flare loop arcade, has provided strong evidence that ion acceleration is also related to magnetic reconnection. Flare particle acceleration is shown to have a close relationship to impulsive Solar Energetic Particle (SEP) events observed in the interplanetary medium, and also to both fast coronal mass ejections and gradual SEP events. New instrumentation to provide the high sensitivity and wide dynamic range hard X-ray and γ-ray measurements, plus energetic neutral atom (ENA) imaging of SEPs above ∼2 R⊙, will enable the next great leap forward in understanding particle acceleration and energy release is large solar eruptions-solar flares and associated fast coronal mass ejections (CMEs). © 2011 Springer Science+Business Media B.V.

Moon H.J.,Dankook University | Ryu S.H.,Dankook University | Kim J.T.,Kyung Hee University
Energy and Buildings | Year: 2014

The building envelope is normally subject to thermal and moisture gradients in practice. Due to the interrelationship, thermal and moisture transfer should be simultaneously calculated for an accurate building performance evaluation. The aim of this study is to investigate the effect of moisture transportation on energy efficiency, thermal comfort and mould growth risks in residential buildings based on the hygrothermal simulation. First, hygrothermal simulation is conducted to evaluate the energy efficiency and IAQ in the selected residential building. This paper also provides characteristics of the hygrothermal properties of domestic building materials which are used for the selected residential building. Differences between experimental data for the domestic materials and properties from embedded data in the hygrothermal simulation program are discussed. Second, a hygrothermal calculation model is calibrated with the measurement data for indoor air temperature and relative humidity in the selected residential building. Lastly, we illustrate the effect of moisture transfer on the overall building performance by comparing the hygrothermal simulation results with thermal-only simulation (only consideration of heat transfer through the building envelope) results. The results suggest that heating and cooling energy can be underestimated without consideration of moisture transportation mechanisms in the building energy simulation. Moreover, results show that the moisture buffering effect could significantly reduce the amplitude of relative humidity fluctuations during all seasons. © 2014 Elsevier B.V. All rights reserved.

Feagan B.G.,University of Western Ontario | Rutgeerts P.,Catholic University of Leuven | Sands B.E.,Mount Sinai School of Medicine | Hanauer S.,University of Chicago | And 13 more authors.
New England Journal of Medicine | Year: 2013

BACKGROUND: Gut-selective blockade of lymphocyte trafficking by vedolizumab may constitute effective treatment for ulcerative colitis. METHODS: We conducted two integrated randomized, double-blind, placebo-controlled trials of vedolizumab in patients with active disease. In the trial of induction therapy, 374 patients (cohort 1) received vedolizumab (at a dose of 300 mg) or placebo intravenously at weeks 0 and 2, and 521 patients (cohort 2) received open-label vedolizumab at weeks 0 and 2, with disease evaluation at week 6. In the trial of maintenance therapy, patients in either cohort who had a response to vedolizumab at week 6 were randomly assigned to continue receiving vedolizumab every 8 or 4 weeks or to switch to placebo for up to 52 weeks. A response was defined as a reduction in the Mayo Clinic score (range, 0 to 12, with higher scores indicating more active disease) of at least 3 points and a decrease of at least 30% from baseline, with an accompanying decrease in the rectal bleeding subscore of at least 1 point or an absolute rectal bleeding subscore of 0 or 1. RESULTS: Response rates at week 6 were 47.1% and 25.5% among patients in the vedolizumab group and placebo group, respectively (difference with adjustment for stratification factors, 21.7 percentage points; 95% confidence interval [CI], 11.6 to 31.7; P<0.001). At week 52, 41.8% of patients who continued to receive vedolizumab every 8 weeks and 44.8% of patients who continued to receive vedolizumab every 4 weeks were in clinical remission (Mayo Clinic score ≤2 and no subscore >1), as compared with 15.9% of patients who switched to placebo (adjusted difference, 26.1 percentage points for vedolizumab every 8 weeks vs. placebo [95% CI, 14.9 to 37.2; P<0.001] and 29.1 percentage points for vedolizumab every 4 weeks vs. placebo [95% CI, 17.9 to 40.4; P<0.001]). The frequency of adverse events was similar in the vedolizumab and placebo groups. CONCLUSIONS: Vedolizumab was more effective than placebo as induction and maintenance therapy for ulcerative colitis. Copyright © 2013 Massachusetts Medical Society.

Kim D.-H.,Kyung Hee University
Journal of Ginseng Research | Year: 2012

The major commercial ginsengs are Panax ginseng Meyer (Korean ginseng), P. quinquifolium L. (American ginseng), and P. notoginseng (Burk.) FH Chen (Notoginseng). P. ginseng is the most commonly used as an adaptogenic agent and has been shown to enhance physical performance, promote vitality, increase resistance to stress and aging, and have immunomodulatory activity. These ginsengs contain saponins, which can be classified as dammarane-type, ocotillol-type and oleanane-type oligoglycosides, and polysaccharides as main constituents. Dammarane ginsenosides are transformed into compounds such as the ginsenosides Rg3, Rg5, and Rk1 by steaming and heating and are metabolized into metabolites such as compound K, ginsenoside Rh1, protoand panaxatriol by intestinal microflora. These metabolites are nonpolar, pharmacologically active and easily absorbed from the gastrointestinal tract. However, the activities metabolizing these constituents into bioactive compounds differ significantly among individuals because all individuals possess characteristic indigenous strains of intestinal bacteria. To overcome this difference, ginsengs fermented with enzymes or microbes have been developed. © The Korean Society of Ginseng.

Lee H.B.,Sungkyunkwan University | Lee T.R.,Northwestern University | Chang Y.S.,Kyung Hee University
Journal of Fluids and Structures | Year: 2013

Flow-induced vibration (FIV) by vortex shedding behind a submerged cylinder can lead to damage of nuclear components. With respect to such a serious scenario, various experiments and numerical simulations have been conducted to predict the vibration phenomena. Especially in simulation, the immersed finite element method (IFEM) is a promising approach to solve fluid-structure interaction problems because it needs less computational resources. In this paper, two-dimensional motions of cylinders are simulated by using IFEM to obtain their vibration characteristics. Three benchmark tests such as flow past a fixed circular cylinder, in-line oscillation of a circular cylinder and flow-induced vibration with uni-directional motion are performed to verify the proposed numerical method. Furthermore, bi-directional motions of two horizontally and vertically arranged cylinders as well as that of a single cylinder in fluid flow are analyzed, and then key findings are fully discussed. © 2012 Elsevier Ltd.

Kim M.J.,Kyung Hee University
Automation in Construction | Year: 2013

Research on augmented reality has mostly explored technical options; thus, currently, there is a limited understanding of human experiences with digitally augmented environments in mobile devices. Through the reviews of related works, this paper proposes a novel concept of context immersion, with the key features emphasizing the potential of augmented reality embodied in smart phones. The framework of the context immersion is structured around a combination of three dimensions, time and location-based context, object-based context and user-based context, where users can experience immersion in augmented environments, but still be connected to a real context in the physical world. A customized questionnaire was developed based on the factors of the context immersion, and the experience of creating a digital exhibition was presented as a case study to illustrate the utility of context immersion as an analytical tool for mobile augmented reality applications. Through understanding the user experience in mobile digital exhibitions, crucial components of context immersion were identified for the design and implementation of mobile augmented reality. Finally, implications of the results and the direction for the development of mobile augmented reality are presented. © 2012 Elsevier B.V.

Lee S.,Kyung Hee University
Image and Vision Computing | Year: 2013

We propose a novel symmetry-driven Bayesian framework to incorporate structural shape into conventional geometrical shape descriptor of an image indexing and retrieval. We use rotation and reflection symmetries for structural shape description. Symmetry detection on each shape image provides a qualitative and a quantitative categorization of the types and the degrees of symmetry level. The posterior shape similarity enhances the shape matching performance based on the symmetry structural discrimination. Experimental results show statistically significant improvement on retrieval accuracy over the state of the art methods on MPEG-7 data set. © 2013 Elsevier B.V.

Heo J.S.,Kyung Hee University | Lee J.-C.,Chonbuk National University
Journal of Cellular Biochemistry | Year: 2011

Wnt/β-catenin signaling regulates various cellular events involved in the proliferation and differentiation and these events are affected sensitively by applying to mechanical stimuli. However, the mechanisms by which mechanical force stimulates cardiomyogenesis are not extensively explored. In this study we investigated the cellular mechanisms by which β-catenin signaling regulates cardiac differentiation of strain-subjected embryonic stem (ES) cells. The application of cells to cyclic strain increased beating cardiomyocyte foci with the attendant increases of Cx 43 and Nkx 2.5 proteins. Anti-oxidants such as vitamin C or N-acetyl cysteine (NAC) blocked the strain-mediated increases of Cx 43, Nkx 2.5, and a5/b1 integrins. These anti-oxidants also suppressed the activation of phosphoinositide 3-kinase (PI3K) and Akt in cyclic strain-subjected cells. Western blot analysis revealed that PI3K is a critical downstream effector of b1 integrin signaling and mediates Cx 43 and Nkx 2.5 expression in cyclic strain-applied ES cells. Cyclic strain increased the expression of β-catenin and stimulated its nuclear translocation from the cytosol, which was prevented by anti-oxidant treatment. In addition, the application to cyclic strain increased mRNA expression of β-catenin target genes, Axin2 and c-myc, as well as the phosphorylation of glycogen synthase kinase-3β. Furthermore, the blockage of β-catenin by its specific siRNA transfection diminished the cellular levels of Cx 43 and Nkx 2.5 proteins and the number of beating cardiomyocyte foci. Collectively, these results suggest that β-catenin-mediated signaling is required for cyclic strainstimulated cardiomyogenesis through ROS-dependent and integrin-mediated PI3K-Akt signaling cascades. J. Cell. Biochem. © 2011 Wiley-Liss, Inc.

Kyun Lee S.,Magnachip Semiconductor Inc. | Yeog Son J.,Kyung Hee University
Applied Physics Letters | Year: 2012

Epitaxial (0001) ZnO thin films were grown on (111) Si substrates buffered with intermediate epitaxial (111) yttria-stabilized zirconia (YSZ) layers by pulsed laser deposition (PLD). X-ray diffraction and transmission electron microscopy characterizations revealed that the YSZ buffer layers enabled the epitaxial growth of structurally high quality ZnO films and an atomically sharp ZnO/YSZ interface, proving to be an effective epitaxial template. The epitaxial orientation relationships were revealed as follows: (0001) ZnO¶(111) YSZ¶ (111) Si and [1̄21̄0] ZnO ¶ [1̄10] YSZ ¶ [1̄10] Si. Room temperature photoluminescence spectrum of the ZnO films showed the excitonic ultraviolet emission with few green emissions relevant to oxygen vacancies in the film. Furthermore, we fabricated ZnO nanostructures on the same (111) YSZ¶(111) Si substrates by simply manipulating PLD conditions for the epitaxial film growth. The size control of the ZnO nanodots was realized by varying the number of laser pulses. A blueshift behavior induced by quantum confinement was observed, as the nanodot size decreases. © 2012 American Institute of Physics.

Park Y.,Kyung Hee University
Korean Journal of Medical History | Year: 2013

Sherwood Hall established a tuberculosis sanatorium in 1928 in Haeju, Hwanghaedo Province. While founding Haiju Sanatorium, he had to overcome a couple of problems. Firstly, foreign missions could not afford a sanatorium. The Methodist mission that dispatched Hall initially expressed a negative response to his endeavors. Ms. Verburg's bequest finally enabled Hall to build a sanatorium. The next obstacle was the objections of neighbors. To overcome opposition, Hall called the sanatorium a School of Hygiene for the Tuberculosis. Finding staffs, nurses in particular, was another problem. Hall stressed that, with precautionary measures, there was relatively little risk. Hall tried to furnish the sanatorium with the most modern facilities and make the sanatorium a place where the public was taught to fight against tuberculosis. Furthermore, Hall built a model farm in conjunction with the sanatorium. The farm would work not only as a stock farm for providing milk and meat but also as a field for occupational therapy. In 1932, in order to secure funding for the expansion of the sanatorium, Hall published the first Christmas seals in Korea, using the sale as an opportunity to organize a civil movement. The relationship of the Haiju Sanatorium with the colonial power was very amicable. Hall was able to establish the sanatorium through the generous co-operation of the colonial government. To the colonial power, the establishment of a tuberculosis sanatorium would mean a lessening of the suffering and death rate from tuberculosis. However, the situation changed in the early 1930s. The colonial power ruled out one of its potentially greatest allies, the missionary power. When the Association for Tuberculosis Prevention of Hwanghaedo Province was established, Hall was appointed to none of the major positions. Medical missionaries could be a threat to the colonial power, which wanted to lead the anti-tuberculosis movement. In 1940, Hall was expelled from Korea, being allegedly accused as a spy of America.

Yoon P.H.,University of Maryland University College | Yoon P.H.,Kyung Hee University
Geophysical Research Letters | Year: 2011

A recent observation shows that large-amplitude whistler waves propagating obliquely with respect to the ambient magnetic field may be responsible for energizing the radiation belt electrons to relativistic energies (MeV) within a time scale as short as a fraction of a second. Test-particle simulations available in the literature invariably adopt simple model wave forms for the oblique whistlers, such that rigorous analysis of these waves have not been performed to this date. The present Letter solves fully nonlinear cold electron fluid equation for obliquely propagating large-amplitude whistlers. Relativistic test particle simulation is then performed over these exact wave solutions, and it is shown that a population of initially low energy electrons can be accelerated tocal O 10 MeV energies, within a few seconds time scale. Copyright 2011 by the American Geophysical Union.

Je Y.,Kyung Hee University | Devivo I.,Harvard University | Giovannucci E.,Harvard University
British Journal of Cancer | Year: 2014

Background:Previous epidemiologic studies have shown inconsistent results for the association between alcohol intake and endometrial cancer risk. Most of the studies, however, assessed alcohol intake after cancer diagnosis, or measured alcohol intake at baseline only.Methods:We prospectively examined the association between alcohol intake and endometrial cancer risk in the Nurses' Health Study with 68 067 female participants aged 34-59 years in 1980. Alcohol intake was measured several times with validated dietary questionnaires. We calculated cumulative average alcohol intake to represent long-term intakes of individual subjects. Using Cox proportional hazards models, we estimated incidence rate ratios (RRs) and 95% confidence intervals (CIs) for endometrial cancer risk after controlling for several risk factors simultaneously.Results:We identified a total of 794 invasive endometrial adenocarcinoma from 1980 to 2010. We found an inverse association among alcohol drinkers (multivariable RR=0.81; 95% CI: 0.68-0.96) compared with nondrinkers. Women with light alcohol intake of <5 g per day (∼half drink per day) had a 22% lower risk of endometrial cancer (multivariable RR=0.78; 95% CI: 0.66-0.94). Higher intake of alcohol, however, did not provide additional benefits against endometrial cancer: multivariable RRs for 5-14.9 g (∼1 drink), 15-29.9 g (∼2 drinks), or ≥30 g (≥2 drinks) versus 0 g per day were 0.88, 0.83, and 0.78 (95% CI: 0.49-1.25), respectively. The lower risk among drinkers (∼half drink per day) appeared to be stronger for obese women, but no significant interaction by body mass index was found.Conclusions:This study provides prospective evidence for an inverse association between light alcohol intake (∼half drink per day) in the long term and endometrial cancer risk, but above that level no significant association was found. © 2014 Cancer Research UK.

Alishahiha M.,Institute for Research in Fundamental Sciences | Yavartanoo H.,Kyung Hee University | Yavartanoo H.,CAS Institute of Theoretical Physics
Classical and Quantum Gravity | Year: 2014

We show that the IR action of the healthy non-projectable Hořava-Lifshitz gravity and its small modification exhibit Lifshitz and hyperscaling violating solutions, respectively, though it does not have the corresponding static black hole solutions. The model may also have an AdS 2 ×Rd vacuum solution. © 2014 IOP Publishing Ltd.

Ha Y.-M.,Gyeongsang National University | Hwang W.J.,Kyung Hee University
International Journal of Mental Health and Addiction | Year: 2014

Internet addiction, especially its prevalence among adolescents and its predictors, has been the focus of much research. Few studies have investigated gender differences in the relationship between Internet addiction and psychological health among adolescents. The present study investigated gender differences in Internet addiction associated with self-rated health, subjective happiness, and depressive symptoms among Korean adolescents aged 12 to 18 years using a nationally representative dataset. Data from 56,086 students (28,712 boys and 27,374 girls) from 400 middle schools and 400 high schools were analyzed. We found that 2.8 % of the students (3.6 % boys and 1.9 % girls) were addicted users, and the prevalence of Internet addiction was higher in boys than in girls. In multiple logistic regression analysis, three psychological health indicators including poor self-rated health, subjective unhappiness, and depressive symptoms were significantly related with Internet addiction in boys and girls. Girls with emotional difficulties such as subjective unhappiness or depressive symptoms had much higher risks of Internet addiction than did boys with similar problems. Further attention should be given to developing Internet addiction prevention and intervention programs that are tailored to fit boys’ and girls’ different needs. © 2014, Springer Science+Business Media New York.

Lee T.H.,Soonchunhyang University | Lee C.K.,Kyung Hee University
Clinical Endoscopy | Year: 2014

Adequate sedation and analgesia are considered essential requirements to relieve patient discomfort and pain and ultimately to improve the outcomes of modern gastrointestinal endoscopic procedures. The willingness of patients to undergo sedation during endoscopy has increased steadily in recent years and standard sedation practices are needed for both patient safety and successful procedural outcomes. Therefore, regular training and education of healthcare providers is warranted. However, training curricula and guidelines for endoscopic sedation may have conflicts according to varying legal frameworks and/or social security systems of each country, and well-recognized endoscopic sedation training systems are not currently available in all endoscopy units. Although European and American curricula for endoscopic sedation have been extensively developed, general curricula and guidelines for each country and institution are also needed. In this review, an overview of recent curricula and guidelines for training and basic performance of endoscopic sedation is presented based on the current literature. © 2014 Korean Society of Gastrointestinal Endoscopy.

Lee S.,Kyung Hee University
IEEE Signal Processing Letters | Year: 2014

Recently, many consumer time-of-flight depth cameras have been introduced that provide direct 3-D geometry measurement of real world objects in real-time. However, these cameras suffer from motion blur artifact when there is any movement of camera or target object in the scene causing serious geometry measurement distortions. Unlike other noises, depth camera motion blur is difficult to eliminate using any existing image processing method due to the unique principle of time-of-flight depth calculation. In this letter, we propose a novel depth motion blur detection and deblurring method that can be applied for any ToF depth sensor. Our method utilizes the relations between different phase offsets observed at multiple time slots in ToF sensor. Experimental results show that the proposed method successfully detects motion blur regions and accurately eliminates them with minimal computational cost in real time. © 1994-2012 IEEE.

Shim H.,Yonsei University | Lee S.,Kyung Hee University
Optics Express | Year: 2014

A time-of-flight(ToF) depth sensor produces noisy range data due to scene properties such as surface materials and reflectivity. Sensor measurement frequently includes either a saturated or severely noisy depth and effective depth accuracy is far below its ideal specification. In this paper, we propose a hybrid exposure technique for depth imaging in a ToF sensor so to improve the depth quality. Our method automatically determines an optimal depth for each pixel using two exposure conditions. To show that our algorithm is effective, we compare the proposed algorithm with two conventional methods in qualitative and quantitative manners showing the superior performance of proposed algorithm. © 2014 Optical Society of America.

Kim D.,Kyung Hee University
Electronic Commerce Research and Applications | Year: 2013

This study provides a model that captures the essential features of the social commerce business. The model focuses on the relationship between key decision issues, such as marketing expenditures and the revenue streams that are created. As more social commerce businesses enter the marketplace, they are faced with fierce competition, which may lead to sharp increases in marketing and advertising expenditures. This type of competition may lead the industry away from its optimal development path, and at worst, toward a disruption of the entire industry. Another goal of this study is to examine the possibility that the tragedy of commons may occur in the industry. The basic analysis presents Nash equilibrium results with homogeneous and heterogeneous players. The analysis further specifies the conditions that the tragedy of commons can occur. I discuss the strategic implications and policy directions that may be able to overcome the shortcomings of current business model, and help the industry to achieve more sustainable development. © 2012 Elsevier B.V. All rights reserved.

Hahn W.-H.,Soonchunhyang University | Bae C.-W.,Kyung Hee University
Pediatric Nephrology | Year: 2014

Background: A number of recent reports have suggested that the cystatin C/creatinine (CysC/Cr) ratio might be a useful biomarker of renal function in pediatric patients. In this study we investigated the reference intervals of the serum CysC/Cr ratio for neonates including very low birth weight infants. Case-Diagnosis/Treatment: A total of 883 blood samples were collected from 246 neonates during the first 30 days of life for the concurrent measurement of serum CysC and Cr levels. Infants with symptoms or signs of acute kidney injury, systemic illness, congenital anomaly, or renal pathology were excluded. The association between serum CysC/Cr ratio and the subgroups of patients was also analyzed. Reference intervals of serum CysC/Cr ratio were determined according to the postnatal age and post-conceptional age (PCA). CysC/Cr ratio level increased according to PCA, except in the first three postnatal days. The serum CysC/Cr ratio correlated positively with gestational age at birth, birth weight, postnatal age, and PCA, and negatively with serum CysC and Cr (P < 0.001). Conclusions: Reference levels of serum CysC/Cr ratio were determined according to postnatal age and PCA. As the serum CysC/Cr ratio is dependent on several clinical parameters, these should be considered when assessing the serum CysC/Cr ratio in neonates. © 2013 IPNA.

Kim W.-H.,Samsung | Yeog Son J.,Kyung Hee University
Applied Physics Letters | Year: 2013

Ferroelectric BiFeO3 (BFO) nanodots were prepared on two substrate types, a Nb-doped SrTiO3 (Nb:STO) and a highly ordered pyrolytic graphite (HOPG), using elaborately controllable dip-pen nanolithography (DPN) technology. The lateral dimension and thickness of the formed BFO nanodots exhibited the substrate dependency, resulting in higher aspect ratio with smaller lateral dimension and higher thickness on the hydrophobic HOPG substrate than that of the Nb:STO substrate. Based on piezoelectric force microscope (PFM) measurements, superior ferroelectricity in d33 hysteresis loop of the BFO nanodots on the HOPG was demonstrated by significant reduction in the substrate clamping effect, compared to that on the Nb:STO. © 2013 AIP Publishing LLC.

Koo H.-J.,Kyung Hee University | Whangbo M.-H.,North Carolina State University
Inorganic Chemistry | Year: 2010

We evaluated the intrachain and interchain spin exchanges of Cu 3(P2O6OH) consisting of (Cu2-Cu2-Cu1) ∞ chains by density functional calculations to find that the magnetic properties of Cu3(P2O6OH)2 are not governed by the J1-J2-J2 trimer chain along the c-direction, but by a two-dimensional (2D) antiferromagnetic lattice in which J1-J3-J3 trimer chains along the (a-c/2)-direction are interconnected by J6 monomer chains along the a-direction. Despite its 2D character, Cu3(P2O 6OH)2 shows a 1/3 magnetization plateau because it is a spin-1/2 trimer system with one dominant antiferromagnetic dimer exchange. © 2010 American Chemical Society.

Kim J.E.,Kyung Hee University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

The recent BICEP2 report on the CMB B-mode polarization hints an early Universe energy density at the GUT scale. We add a new 'chaoton' term to our recently proposed hilltop potential to have a large tensor mode fluctuation. The chaoton field slides down from the hilltop when the inflaton field value is small so that an enough e-folding is possible. We also comment how the trans-Planckian decay constant is obtained from some discrete symmetries of ultra-violet completed models. © 2014 The Author.

Lee S.M.,Seoul National University | Park C.M.,Seoul National University | Lee K.H.,Seoul National University | Bahn Y.E.,Seoul National University | And 2 more authors.
Radiology | Year: 2014

Purpose: To retrospectively evaluate the diagnostic performance and complications of C-arm cone-beam computed tomography (CT)-guided percutaneous transthoracic needle biopsy (PTNB) in 1108 patients. Materials and Methods: This retrospective study was approved by the institutional review board with waiver of patient informed consent. From January 2009 to December 2011, 1108 patients (633 male, 475 female; mean age, 62.4 years ± 12.3 [standard deviation]) with 1116 pulmonary lesions (mean size, 2.7 cm ± 1.7) underwent 1153 cone-beam CT-guided PTNBs. A coaxial system with 18-gauge cutting needles was used. Diagnostic performance, complication rate, influencing factors, and patient radiation exposure were investigated. Variables influencing diagnostic performance and complications were assessed by using uni- and multivariate logistic regression analyses. Results: Among 1153 PTNBs, pathologic analysis showed 1148 (99.6%) were technically successful (766 malignant [66.4%], 323 benign [28.0%], and 59 [5.1%] indeterminate). Sensitivity, specificity, and accuracy for diagnosis of malignancy were 95.7% (733 of 766), 100% (323 of 323), and 97.0% (1056 of 1089), respectively. In regard to diagnostic failures (five technical failures, 33 false-negative findings), lesions 1 cm in diameter or smaller and lesions in the lower lobe were significant risk factors (P = .028 and P = .034, respectively). As for complications, pneumothorax and hemoptysis occurred in 196 (17.0%) and 80 (6.9%) procedures, respectively. Multivariate analysis revealed two or more pleural passages and emphysema along the needle pathway were the two most significant risk factors for pneumothorax, and ground-glass nodules were the most significant risk factor for hemoptysis (P < .001 for all). Virtual guidance was a significant protective factor for both pneumothorax and hemoptysis (P < .001 for both). Mean estimated effective radiation dose through cone-beam CT-guided PTNBs was 7.3 mSv ± 4.1. Conclusion: Cone-beam CT-guided PTNB is a highly accurate and safe technique with which to diagnose pulmonary lesions with reasonable radiation exposure. © RSNA, 2013.

Choi I.Y.,Pusan National University | Cho S.H.,Pusan National University | Kim J.T.,Kyung Hee University
Energy and Buildings | Year: 2012

Energy management for housing, which is responsible for 70% of the energy consumption by buildings, is increasing in importance. This study identified the characteristics of energy consumption in high-rise apartment buildings through a series of case studies and resident surveys. The results were as follows: (1) high-rise apartment buildings can be classified according to whether they are mixed-use or general residential buildings and according to the building shape. (2) In the evaluation of the characteristics of electrical energy consumption according to building use, residents in the mixed-use apartments showed higher behavior of active heating management and more actively adjusted their indoor stay, but they consumed more electricity, particularly in summer, than those living in general residential apartments. (3) For the electric energy consumption characteristics according to the building shape, plate-type buildings consumed less energy than tower-type buildings. And the latter consumed 1.48 times more energy than the former in the electricity for common areas. (4) When evaluating the characteristics of liquefied natural gas consumption according to the building shape, it can be seen that plate-type buildings consumed 10% more gas than tower-type buildings. (5) CO 2 emissions in mixed-use buildings were found to be higher than those in general residential buildings. © 2011 Elsevier B.V. All rights reserved.

Kang N.N.,Pusan National University | Cho S.H.,Pusan National University | Kim J.T.,Kyung Hee University
Energy and Buildings | Year: 2012

The purpose of this study is to discuss the energy-saving effects of residents' participation in apartment complexes through the imparting of relevant information and motivation. Therefore, this study compared the results of two separate surveys. Surveys developed based on the government guidelines were utilized to observe and compare residents' consciousness, knowledge and behaviors, before and after providing them with information and performing promotion activities The major findings are as follows: First, the residents' energy-saving consciousness, knowledge, and behavior improved after they were provided with relevant information and exposed to campaigns. Second, these factors improved further if residents had been previously exposed to such information and campaigns at their apartment complexes. Third, energy-saving activities driven by residents' participation instilled a sense of pride in their apartment complex. Hence, this study's examination and discussion of the energy-saving effects of apartment complexes is expected to be utilized as a framework and guideline for the creation of effective energy-saving manuals for apartment residents. © 2011 Elsevier B.V. All rights reserved.

Hong J.-W.,Kyung Hee University | Park K.W.,Sungkyunkwan University
Experimental and Molecular Medicine | Year: 2010

Obesity is a leading risk factor for insulin resistance, hypertension, hyperlipidemia, and cardiovascular complications, collectively referred to as metabolic diseases. Given the prevalence of obesity and its associated medical problems, new strategies are required to prevent or treat obesity and obesity-related metabolic effects. Here we summarize contributors of obesity, and molecular mechanisms controlling adipogenesis from studies in mammalian systems. We also discuss the possibilities of using Drosophila as a genetic model system to advance our understanding of players in fat biology.

Kim J.E.,Kyung Hee University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

The axion search experiments invite a plausible estimation of the axion-photon-photon coupling constant c-aγγ in string models with phenomenologically acceptable visible sectors. We present the calculation of c-aγγ with an exact Peccei-Quinn symmetry. In the Huh-Kim-Kyae Z12 -I orbifold compactification, we obtain c-aγγ=1123388, and the low-temperature axion search experiments will probe the QCD corrected coupling, caγγ≃c-aγγ-1.98≃0.91. © 2014 Elsevier B.V.

Jung S.,Kyung Hee University
Behavioural Processes | Year: 2013

Exploratory factor analysis (EFA) has emerged in the field of animal behavior as a useful tool for determining and assessing latent behavioral constructs. Because the small sample size problem often occurs in this field, a traditional approach, unweighted least squares, has been considered the most feasible choice for EFA. Two new approaches were recently introduced in the statistical literature as viable alternatives to EFA when sample size is small: regularized exploratory factor analysis and generalized exploratory factor analysis. A simulation study is conducted to evaluate the relative performance of these three approaches in terms of factor recovery under various experimental conditions of sample size, degree of overdetermination, and level of communality. In this study, overdetermination and sample size are the meaningful conditions in differentiating the performance of the three approaches in factor recovery. Specifically, when there are a relatively large number of factors, regularized exploratory factor analysis tends to recover the correct factor structure better than the other two approaches. Conversely, when few factors are retained, unweighted least squares tends to recover the factor structure better. Finally, generalized exploratory factor analysis exhibits very poor performance in factor recovery compared to the other approaches. This tendency is particularly prominent as sample size increases. Thus, generalized exploratory factor analysis may not be a good alternative to EFA. Regularized exploratory factor analysis is recommended over unweighted least squares unless small expected number of factors is ensured. © 2013 Elsevier B.V.

The roots of Panax ginseng C.A. Meyer, known as Korean ginseng have been a valuable and important folk medicine in East Asian countries. It mainly used to maintain the homeostasis of the human body, with the presence ofginsenosides and non-saponin compounds like phenol compounds, acidic polysaccharides and polyethylene compounds. Functional genomics aid to annotate based on gene ontology. In this study, we focused on the genes involving in secondary metabolic pathways and to visualize temporal changes of gene expression in ginseng hairy roots with methyl ester methyl jasmonate (MeJA) along with non-treated hairy roots. A 5.774 EST clones were clustered and assembled as 501 contigs and 2.955 singletons. Annotations categorized with molecular functions, biological processes, cellular compounds of gene ontological terms and biochemical functions, enzyme commission to sequences were assigned to metabolic pathways of Kyoto Encyclopedia of Genes and Genomes database. Comparatively, EST sequences are assigned to cellular process, metabolic process, biotic and abiotic stress stimuli, developmental and biological regulations and transports are up-regulated 2-3 fold in MeJA treated hairy roots. 46 different sub groups of enzymes found in the MeJA treated plants. These annotated ESTs represents a significant proportion of the P. ginseng and provides molecular resource for developmental of microarrays for gene expression studies concerning development, metabolism and reproduction.

Kim A.S.,University of Hawaii at Manoa | Kim A.S.,Kyung Hee University
Journal of Membrane Science | Year: 2013

We investigated fundamental aspects of heat and mass transfer of direct contact membrane distillation. Molar flux of water vapor through a membrane pore was analytically obtained by solving Fick's law in the original differential form. Axial variation of the temperature profile was derived as exponentially decreasing, and was found to be linear due to small membrane thickness and dominant heat conduction through the solid part of the membrane. An alternative expression of water vapor pressure at a constant temperature was developed using experimental data of water latent heat for evaporation, and was used to calculate the concentration of water vapor in the membrane pore. The effective diffusion coefficient was obtained by combining Knudsen and Brownian diffusion coefficients with Bosanquet's assumption. The effective diffusivity and mean free path of water vapor slowly decrease in the axial direction, and the vapor concentration increases along the membrane pore primarily due to the linearly decreasing temperature. We found that the required heat flux monotonously increases with the vapor flux through membrane pores. Finite variance of a pore size distribution provides less vapor flux than that of mono-dispersed pores. This is because a number of smaller pores than the average pore size significantly hinders the vapor transport across the porous membrane. Theoretical prediction of permeate flux agrees very well with experimental observations reported in the literature. © 2012 Elsevier B.V.

Miljkovic N.,Massachusetts Institute of Technology | Enright R.,Massachusetts Institute of Technology | Enright R.,University of Limerick | Enright R.,Alcatel - Lucent | And 6 more authors.
Nano Letters | Year: 2013

When droplets coalesce on a superhydrophobic nanostructured surface, the resulting droplet can jump from the surface due to the release of excess surface energy. If designed properly, these superhydrophobic nanostructured surfaces can not only allow for easy droplet removal at micrometric length scales during condensation but also promise to enhance heat transfer performance. However, the rationale for the design of an ideal nanostructured surface as well as heat transfer experiments demonstrating the advantage of this jumping behavior are lacking. Here, we show that silanized copper oxide surfaces created via a simple fabrication method can achieve highly efficient jumping-droplet condensation heat transfer. We experimentally demonstrated a 25% higher overall heat flux and 30% higher condensation heat transfer coefficient compared to state-of-the-art hydrophobic condensing surfaces at low supersaturations (<1.12). This work not only shows significant condensation heat transfer enhancement but also promises a low cost and scalable approach to increase efficiency for applications such as atmospheric water harvesting and dehumidification. Furthermore, the results offer insights and an avenue to achieve high flux superhydrophobic condensation. © 2012 American Chemical Society.

Yu C.,Hanyang University | Lee K.,Hanyang University | You Y.,Kyung Hee University | Cho E.J.,Hanyang University
Advanced Synthesis and Catalysis | Year: 2013

An efficient method for synthesis of the widely applicable 2-substituted benzothiazoles has been developed. The process requires only 0.1 mol% [Ru(bpy)3Cl2], O2, and visible light irradiation with substrates: 2-aminothiophenol and a variety of aldehydes. We established an oxidative quenching of the photoredox catalyst as being the key process in this photoelectrocatalytic cycle. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Kim J.I.,Seoul National University | Kim J.I.,Kyung Hee University | Park C.M.,Seoul National University | Lee S.M.,Seoul National University | Goo J.M.,Seoul National University
European Radiology | Year: 2015

Objectives: To investigate the effect of rapid needle-out patient-rollover approach on the incidence of pneumothorax and drainage catheter placement due to pneumothorax in C-arm Cone-beam CT (CBCT)-guided percutaneous transthoracic needle biopsy (PTNB) of lung lesions. Methods: From May 2011 to December 2012, 1227 PTNBs were performed in 1191 patients with a 17-gauge coaxial needle. 617 biopsies were performed without (conventional-group) and 610 with rapid-rollover approach (rapid-rollover-group). Overall pneumothorax rates and incidences of pneumothorax requiring drainage catheter placement were compared between two groups. Results: There were no significant differences in overall pneumothorax rates between conventional and rapid-rollover groups (19.8 % vs. 23.1 %, p = 0.164). However, pneumothorax rate requiring drainage catheter placement was significantly lower in rapid-rollover-group (1.6 %) than conventional-group (4.2 %) (p = 0.010). Multivariate analysis revealed male, age > 60, bulla crossed, fissure crossed, pleura to target distance > 1.3 cm, emphysema along needle tract, and pleural punctures ≥ 2 were significant risk factors of pneumothorax (p < 0.05). Regarding pneumothorax requiring drainage catheter placement, fissure crossed, bulla crossed, and emphysema along needle tract were significant risk factors (p < 0.05), whereas rapid-rollover approach was an independent protective factor (p = 0.002). Conclusions: The rapid needle-out patient-rollover approach significantly reduced the rate of pneumothorax requiring drainage catheter placement after CBCT-guided PTNB. Key points: • The rapid-rollover approach had little beneficial effect on overall pneumothorax rate. • The rapid-rollover approach significantly reduced drainage catheter placement due to pneumothorax. • The strongest risk factor was pleural punctures ≥ 2 per procedure. • Emphysema along the needle tract was a stronger risk factor than fissure-crossed. © 2015, European Society of Radiology.

Ronald P.C.,University of California at Davis | Ronald P.C.,Joint BioEnergy Institute | Ronald P.C.,Kyung Hee University | Beutler B.,Scripps Research Institute
Science | Year: 2010

The last common ancestor of plants and animals may have lived 1 billion years ago. Plants and animals have occasionally exchanged genes but, for the most part, have countered selective pressures independently. Microbes (bacteria, eukaryotes, and viruses) were omnipresent threats, influencing the direction of multicellular evolution. Receptors that detect molecular signatures of infectious organisms mediate awareness of nonself and are integral to host defense in plants and animals alike. The discoveries leading to elucidation of these receptors and their ligands followed a similar logical and methodological pathway in both plant and animal research.

Kim J.T.,Kyung Hee University | Kim G.,Kangwon National University
Building and Environment | Year: 2010

Optical daylighting technology can deliver natural light to a space in a building where daylight is limited. This study gives an overview of two optical daylighting systems for capturing natural light: light pipe systems and mirror sunlighting systems. The literature on optical system theories and developments is identified and commercial products for optical daylighting systems on the market are described. By using a survey of major applications for optical daylighting systems, this study provides practical advice to building designers and researchers and also shows a light pipe system and a mirror sunlighting system developed from this investigation as well as an evaluation of their performance. The evaluation measured the illuminance of the two optical systems installed in a test room and a living room. This study concluded that optical daylighting systems can provide adequate visual comfort and can save energy if they are carefully designed. © 2009 Elsevier Ltd. All rights reserved.

Kim G.,Kangwon National University | Kim J.T.,Kyung Hee University
Building and Environment | Year: 2010

An essential part of an indoor environment design is to deliver both the visual task needed as well as a healthy lighting system. In this article, healthy residential environment is discussed as an architectural field of light. The development and consolidation of health promotion is presented focusing the discussion on two areas of action: providing healthy light and eliminating harmful light within apartments. In Korea, the possibility for occupants to spend a large amount of time in the sun without proper protection is growing since, many balconies have been eliminated and there is a preference for large windows with improper orientation for the opening. When a balcony as a visual buffer space is eliminated, the distance between occupants and balcony window becomes closer and thus, there is a lager glass area of the window in the field of human view. Eliminating the balcony also removes the overhang structure which works as an obstruction to block the excessive penetration of sunlight. This results in the advent of harmful light in quantitative and qualitative ways; too much light, uncomfortable glare, and UV penetration. This paper discusses issues related to light and healthy living environment. Initially, it deals with the establishment of all design elements in terms of light and surveys examples of current designs. Architectural and optical solutions both to attenuate the harmfulness of light and to improve the visual satisfaction are given issued and their performance is reviewed. © 2009 Elsevier Ltd. All rights reserved.

Kim N.,Kyung Hee University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

We numerically compute the Rényi entropy for four-dimensional free scalar field theory with a spherical entangling surface. As is well known, the Rényi entropy as a function of the boundary area exhibits linear dependence in the leading order. The coefficient of the subleading logarithmic term from our numerical data, as a function of the Rényi order q, agrees nicely with the general prediction of conformal field theory computation. The motivation of this work is also partly to see how the efficiency of numerical computation changes as a function of q. For q < 1 the summation over eigenvalues of reduced density matrix takes longer since the series converges more slowly than for q = 1. For q > 1 the convergence is faster, but the relative error becomes large as a general trend. © 2014 The Author.

Kim J.E.,Kyung Hee University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

The recent BICEP2 result shows that the Universe once has gone through the vacuum with the GUT scale energy density. The implied high scale inflation nullifies the dilution idea of topological defects, strings and domain walls, of the axionic system. In particular, domain walls are disastrous if the domain wall problem with NDW ≥ 2 is present. We argue that the model-independent axion in string compactification with the anomalous U(1)ga gauge symmetry resolves the domain wall problem naturally with a symmetry principle. © 2014 The Author.

Napadow V.,Harvard University | Napadow V.,Kyung Hee University | Harris R.E.,University of Michigan
Arthritis Research and Therapy | Year: 2014

Research suggests that fibromyalgia is a central, widespread pain syndrome supported by a generalized disturbance in central nervous system pain processing. Over the past decades, multiple lines of research have identified the locus for many functional, chronic pain disorders to the central nervous system, and the brain. In recent years, brain neuroimaging techniques have heralded a revolution in our understanding of chronic pain, as they have allowed researchers to non-invasively (or minimally invasively) evaluate human patients suffering from various pain disorders. While many neuroimaging techniques have been developed, growing interest in two specific imaging modalities has led to significant contributions to chronic pain research. For instance, resting functional connectivity magnetic resonance imaging (fcMRI) is a recent adaptation of fMRI that examines intrinsic brain connectivity - defined as synchronous oscillations of the fMRI signal that occurs in the resting basal state. Proton magnetic resonance spectroscopy (1H-MRS) is a non-invasive magnetic resonance imaging technique that can quantify the concentration of multiple metabolites within the human brain. This review will outline recent applications of the complementary imaging techniques - fcMRI and 1H-MRS - to improve our understanding of fibromyalgia pathophysiology and how pharmacological and non-pharmacological therapies contribute to analgesia in these patients. A better understanding of the brain in chronic pain, with specific linkage as to which neural processes relate to spontaneous pain perception and hyperalgesia, will greatly improve our ability to develop novel therapeutics. Neuroimaging will play a growing role in the translational research approaches needed to make this a reality. © 2014 Napadow and Harris; licensee BioMed Central Ltd.

Lee C.,Columbia University | Yan H.,Columbia University | Brus L.E.,Columbia University | Heinz T.F.,Columbia University | And 2 more authors.
ACS Nano | Year: 2010

Molybdenum disulfide (MoS2) of single- and few-layer thickness was exfoliated on SiO2/Si substrate and characterized by Raman spectroscopy. The number of S-Mo-S layers of the samples was independently determined by contact-mode atomic force microscopy. Two Raman modes, E 12g and A1g, exhibited sensitive thickness dependence, with the frequency of the former decreasing and that of the latter increasing with thickness. The results provide a convenient and reliable means for determining layer thickness with atomic-level precision. The opposite direction of the frequency shifts, which cannot be explained solely by van der Waals interlayer coupling, is attributed to Coulombic interactions and possible stacking-induced changes of the intralayer bonding. This work exemplifies the evolution of structural parameters in layered materials in changing from the three-dimensional to the two-dimensional regime. © 2010 American Chemical Society.

Kim H.,Kyung Hee University | Ahn H.S.,Pohang University of Science and Technology | Kim M.H.,Pohang University of Science and Technology
Journal of Heat Transfer | Year: 2010

The pool boiling characteristics of water-based nanofluids with alumina and titania nanoparticles of 0.01 vol % were investigated on a thermally heated disk heater at saturated temperature and atmospheric pressure. The results confirmed the findings of previous studies that nanofluids can significantly enhance the critical heat flux (CHF), resulting in a large increase in the wall superheat. It was found that some nanoparticles deposit on the heater surface during nucleate boiling, and the surface modification due to the deposition results in the same magnitude of CHF enhancement in pure water as for nanofluids. Subsequent to the boiling experiments, the interfacial properties of the heater surfaces were examined using dynamic wetting of an evaporating water droplet. As the surface temperature increased, the evaporating meniscus on the clean surface suddenly receded toward the liquid due to the evaporation recoil force on the liquid-vapor interface, but the nanoparticle-fouled surface exhibited stable wetting of the liquid meniscus even at a remarkably higher wall superheat. The heat flux gain attainable due to the improved wetting of the evaporating meniscus on the fouled surface showed good agreement with the CHF enhancement during nanofluid boiling. It is supposed that the nanoparticle layer increases the stability of the evaporating microlayer underneath a bubble growing on a heated surface and thus the irreversible growth of a hot/dry spot is inhibited even at a high wall superheat, resulting in the CHF enhancement observed when boiling nanofluids. © 2010 by ASME.

Lee J.C.,Soonchunhyang University | Lee S.-H.,Kyung Hee University | Peters C.,University of Washington | Riew K.D.,University of Washington
Journal of Bone and Joint Surgery - American Volume | Year: 2014

Background: Adjacent-segment pathology is an important issue involving the cervical spine, but there have been few comprehensive studies of this problem. The purpose of the current study was to determine the risk factors for adjacent-segment pathology and to compare the survivorship of adjacent segments in patients who underwent cervical spine operations including arthrodesis and motion-sparing procedures.Methods: This was a retrospective analysis of a consecutive series of 1358 patients with radiculopathy, myelopathy, or myeloradiculopathy who underwent cervical spine surgery performed by a single surgeon. We calculated the annual incidence of adjacent-segment pathology requiring surgery and, with use of Kaplan-Meier analysis, determined survivorship. Cox regression analysis was used to identify risk factors.Results: The index surgical procedures included cervical arthrodesis (1095 patients; 1038 anterior, twenty-nine posterior, and twenty-eight combined anterior and posterior), posterior decompression (214 patients; 145 laminoplasty and sixty-nine foraminotomy), arthroplasty (thirty-two patients), and a combination of arthroplasty and anterior arthrodesis (seventeen patients). Secondary surgery on adjacent segments occurred at a relatively constant rate of 2.3% per year (95% confidence interval, 1.9 to 2.9). Kaplan-Meier analysis predicted that 21.9% of patients would need secondary surgery on adjacent segments by ten years postoperatively. Factors increasing the risk were smoking, female sex, and type of procedure. The posterior arthrodesis group (posterior-only or combined anterior and posterior arthrodesis) had a 7.5-times greater risk of adjacent-segment pathology requiring reoperation than posterior decompression, and a 3.0-times greater risk than the anterior arthrodesis group. However, when we compared the anterior cervical arthrodesis group, the arthroplasty group (arthroplasty or hybrid arthroplasty), and the posterior decompression group to each other, there were no significant differences. Age, neurological diagnosis, diabetes, and number of surgically treated segments were not significant risk factors.Conclusions: Patients treated with posterior or combined anterior and posterior arthrodesis were far more likely to develop clinical adjacent-segment pathology requiring surgery than those treated with posterior decompression or anterior arthrodesis. Smokers and women had a higher chance of clinical adjacent-segment pathology after cervical spine surgery.Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence. © 2014 by The Journal of Bone and Joint Surgery, Incorporated.

Min C.,Kyung Hee University
Journal of Computational Physics | Year: 2010

In this paper, we consider reinitializing level functions through equation φt + sgn(φ0)(||▽φ|| - 1 = 0[16]. The method of Russo and Smereka [11] is taken in the spatial discretization of the equation. The spatial discretization is, simply speaking, the second order ENO finite difference with subcell resolution near the interface. Our main interest is on the temporal discretization of the equation. We compare the three temporal discretizations: the second order Runge-Kutta method, the forward Euler method, and a Gauss- Seidel iteration of the forward Euler method. The fact that the time in the equation is fictitious makes a hypothesis that all the temporal discretizations result in the same result in their stationary states. The fact that the absolute stability region of the forward Euler method is not wide enough to include all the eigenvalues of the linearized semi-discrete system of the second order ENO spatial discretization makes another hypothesis that the forward Euler temporal discretization should invoke numerical instability. Our results in this paper contradict both the hypotheses. The Runge-Kutta and Gauss-Seidel methods obtain the second order accuracy, and the forward Euler method converges with order between one and two. Examining all their properties, we conclude that the Gauss-Seidel method is the best among the three. Compared to the Runge-Kutta, it is twice faster and requires memory two times less with the same accuracy. © 2009 Elsevier Inc. All rights reserved.

Hwang Y.,DePaul University | Hwang Y.,Kyung Hee University
Computers in Human Behavior | Year: 2010

For e-commerce designers and human-computer interaction researchers, electronic commerce (e-commerce) systems adoption factors and the moderating effects of gender are important topics. Even though there are research endeavors to explain e-commerce systems adoption, one of the main questions to be answered is regarding the normative and affective factors based on the theory of reasoned action and self-determination theory. In this paper, social norms, perceived enjoyment, and their relationships to intention to adopt an e-commerce system are tested (n = 322). Furthermore, the moderating effects of gender are tested based on the sociolinguistic literature. As expected, the influence of social norms is stronger in the female group while the influence of enjoyment is stronger in the male group. Theoretical and practical implications of these findings are discussed in the paper. © 2010 Elsevier Ltd. All rights reserved.

Gong Z.,University of Texas M. D. Anderson Cancer Center | Kim J.-E.,Kyung Hee University | Leung C.C.Y.,University of Alberta | Glover J.N.M.,University of Alberta | Chen J.,University of Texas M. D. Anderson Cancer Center
Molecular Cell | Year: 2010

Human TopBP1 plays a critical role in the control of DNA replication checkpoint. In this study, we report a specific interaction between TopBP1 and BACH1/FANCJ, a DNA helicase involved in the repair of DNA crosslinks. The TopBP1/BACH1 interaction is mediated by the very C-terminal tandem BRCT domains of TopBP1 and S phase-specific phosphorylation of BACH1 at Thr 1133 site. Interestingly, we demonstrate that depletion of TopBP1 or BACH1 attenuates the loading of RPA on chromatin. Moreover, both TopBP1 and BACH1 are required for ATR-dependent phosphorylation events in response to replication stress. Taken together, our data suggest that BACH1 has an unexpected early role in replication checkpoint control. A specific interaction between TopBP1 and BACH1 is likely to be required for the extension of single-stranded DNA regions and RPA loading following replication stress, which is a prerequisite for the subsequent activation of replication checkpoint. © 2010 Elsevier Inc. All rights reserved.

This study explores the trajectory of suicidal ideation in childhood and adolescence and identifies its strong predictors. Secondary data obtained from two nationally representative cohorts of South Korean youth were longitudinally analyzed using frequencies, percentages, and discrete time survival analysis. This study revealed an increase in the occurrence of suicidal ideation in adolescence, a higher prevalence of suicidal ideation among females than among males, and differences in predictors of suicide ideation by developmental stages and gender. The results suggest that multifaceted factors specific to developmental stages and gender should be simultaneously considered to diminish the occurrences of suicidal ideation. © 2012 The American Association of Suicidology.

Kim J.T.,Kyung Hee University | Kim G.,Kangwon National University
Indoor and Built Environment | Year: 2010

Controlling or avoiding direct sun beam shining into the interior is a key criterion for consideration in most architectural daylighting designs. This treatment is mainly intended to attenuate the adverse glare and contrast associated with direct sunlight and to lessen the negative contribution of direct sunlight on the cooling load. Window shades are commonly used in Korea to reduce heat gains in the form of direct beam radiation, particularly in summer. Very often they consist of non-movable structures, such as overhangs, vertical fins or composition of both, forming eggcrate-type systems, and ideally should be designed by incorporating these methods. One of the simplest sunlighting controls is Venetian blind. It plays a role in excluding direct sunlight but reflecting light to rear interior, while still allowing a view to exterior. The blinds also go far toward improving uniformity in illuminance. External shading devices are much more effective than internal shading devices. However, it is not popular because of cost, maintenance, and esthetic reasons. We developed an experimental configuration of external shading device, providing better performance of shading and view. A series of simulations and measurements have verified the differentiated advantages in illumination and building energy consumption by using this system. © 2010 SAGE Publications.

Magara T.,Kyung Hee University
Astrophysical Journal | Year: 2011

Flux emergence is a complicated process involving flow and magnetic field, which provides a way of injecting magnetic energy into the solar atmosphere. We show that energy injection via this complicated process is characterized by a physical quantity called the emergence velocity, which is determined by the spatial relationship between the flow velocity and magnetic field vectors. By using this quantity, we demonstrate that the geometric shape of magnetic field might play an important role in the energy injection via flux emergence. © 2011. The American Astronomical Society. All rights reserved.

Hwang Y.-H.,Korea Advanced Institute of Science and Technology | Kim D.-G.,Kyung Hee University | Shin H.-S.,Korea Advanced Institute of Science and Technology
Applied Catalysis B: Environmental | Year: 2011

Application of nano zero valent iron (NZVI) is an innovative technology for water treatment and soil/groundwater remediation. Among various NZVI synthesis methods, chemical reduction is widely used due to its simplicity and chemical homogeneity. However, the synthesis procedure had not yet been clearly standardized. In this study, the effects of reaction conditions such as reaction time and NZVI concentration on NZVI characteristics and reactivity were investigated. Nanocluster and whisker structures were obtained under fast reduction conditions. The particle size was dramatically decreased from 87.4nm to 9.5nm under short reaction time and high reductant concentration. Simultaneously, the BET surface area was increased from 8.4m2/g to 45.4m2/g. The reactivity of NZVI was evaluated by a nitrate reduction test. The experimental data were interpreted by pseudo first order kinetics with first order deactivation. The reactivity was increased in the direction of high reductant concentration and fast synthesis, although deactivation increased in the same direction. Among the 4 reaction steps for NZVI synthesis, the nuclei formation step was determined to be the key step in determining NZVI characteristics. Therefore, it is important to control the reaction time and concentration in order to maximize the efficiency of NZVI. © 2011 Elsevier B.V.

Hong J.,Massachusetts Institute of Technology | Park H.,Kyung Hee University
Colloids and Surfaces A: Physicochemical and Engineering Aspects | Year: 2011

We demonstrated mechanistic insight into all block copolymer micelle (BCM) multilayer films prepared using three methods: dip-, spin- and spray-assisted layer-by-layer (LbL) methods. The resultant films showed specific film growth mechanisms such as linear and non-linear growth, and distinct surface morphologies with tunable porosities were demonstrated via the respective assembly methods, despite an identical polymer composition and concentration. In particular, the porosity, as measured by ellipsometry, was readily controlled from 2.6% to 55.9% by manipulating the LbL deposition methods and thickness. AFM and SEM data indicate the fundamental morphological evolution of 0-dimensional nano-objects and control of the surface roughness by means of the various deposition methods. Therefore, the systematic study of the three LbL methods shown herein provides deep insight into the control of the structures of multilayer films according to the characteristics of nano-objects and assembly methods. © 2011 Elsevier B.V.

Cho S.-H.,Yonsei University | Kim J.,Yonsei University | Kim J.,Kyung Hee University
Astronomical Journal | Year: 2012

We carried out simultaneous observations of four maser lines, SiO v= 1, 2, 29SiO v= 0, J= 1-0, and H 2O 6 16-5 23, toward 83 known SiO maser sources without H 2O maser detections using the Korean VLBI Network single dish telescopes. Both SiO and H 2O masers were detected from 14 sources, resulting in a detection rate of 16.9%. H 2O maser emission without SiO maser emission was detected from one source. Therefore, H 2O maser emission was newly detected from 15 sources. SiO maser emission without H 2O detection was detected from 55 sources, which gives a total SiO maser detection rate of 83.1% when including sources that have both SiO and H 2O maser emission detected. SiO v= 2 maser emission was detected from nine sources without v= 1 maser detection. The SiO v= 2 maser sources without the v= 1 maser detections need to be investigated, with a large number of v= 2 only maser sources related to the development of dust shells and their evolutionary sequence from asymptotic giant branch (AGB) to post-AGB stars. The average values of the peak and integrated antenna temperature ratios of H 2O to SiO masers are 0.44 and 0.28 in the 14 sources that have both SiO and H 2O detections. Observational characteristics of several individual sources are noted and the dependence of the different maser intensity ratios on the stellar phase is discussed. In addition, the observational results of SiO and H 2O masers are discussed in IRAS two-color diagrams. © 2012. The American Astronomical Society. All rights reserved.

Kim H.,Kyung Hee University
Nanoscale Research Letters | Year: 2011

Nanofluids (suspensions of nanometer-sized particles in base fluids) have recently been shown to have nucleate boiling critical heat flux (CHF) far superior to that of the pure base fluid. Over the past decade, numerous experimental and analytical studies on the nucleate boiling CHF of nanofluids have been conducted. The purpose of this article is to provide an exhaustive review of these studies. The characteristics of CHF enhancement in nanofluids are systemically presented according to the effects of the primary boiling parameters. Research efforts to identify the effects of nanoparticles underlying irregular enhancement phenomena of CHF in nanofluids are then presented. Also, attempts to explain the physical mechanism based on available CHF theories are described. Finally, future research needs are identified. © 2011 Kim.

Kwon O.,Kyung Hee University
Decision Support Systems | Year: 2010

Privacy management is crucial in conducting pervasive computing services. The Platform for Privacy Preferences (P3P) is one of the most significant efforts currently underway for users of Web-based services. Since users are typically nomadic in pervasive computing services, however, their specific privacy concerns change dynamically with context. This leads us to develop a dynamically adjusting P3P-based policy for a personalized, privacy-aware service as a core element of secure pervasive computing. The purpose of this paper is to propose dynamically and flexibly a pervasive P3P-based negotiation mechanism for a privacy control of those functions. To do so, we consider and implement a multi-agent negotiation mechanism on top of a pervasive P3P system. © 2010 Elsevier B.V. All rights reserved.

Choi B.G.,KAIST | Hong J.,Massachusetts Institute of Technology | Hong W.H.,KAIST | Hammond P.T.,Massachusetts Institute of Technology | Park H.,Kyung Hee University
ACS Nano | Year: 2011

The realization of highly flexible and all-solid-state energy-storage devices strongly depends on both the electrical properties and mechanical integrity of the constitutive materials and the controlled assembly of electrode and solid electrolyte. Herein we report the preparation of all-solid-state flexible supercapacitors (SCs) through the easy assembly of functionalized reduced graphene oxide (f-RGO) thin films (as electrode) and solvent-cast Nafion electrolyte membranes (as electrolyte and separator). In particular, the f-RGO-based SCs (f-RGO-SCs) showed a 2-fold higher specific capacitance (118.5 F/g at 1 A/g) and rate capability (90% retention at 30 A/g) compared to those of all-solid-state graphene SCs (62.3 F/g at 1A/g and 48% retention at 30 A/g). As proven by the 4-fold faster relaxation of the f-RGO-SCs than that of the RGO-SCs and more capacitive behavior of the former at the low-frequency region, these results were attributed to the facilitated ionic transport at the electrical double layer by means of the interfacial engineering of RGO by Nafion. Moreover, the superiority of all-solid-state flexible f-RGO-SCs was demonstrated by the good performance durability under the 1000 cycles of charging and discharging due to the mechanical integrity as a consequence of the interconnected networking structures. Therefore, this research provides new insight into the rational design and fabrication of all-solid-state flexible energy-storage devices as well as the fundamental understanding of ion and charge transport at the interface. © 2011 American Chemical Society.

Jung J.,Hanyang University | Kim E.,Hanyang University | You Y.,Kyung Hee University | Cho E.J.,Hanyang University
Advanced Synthesis and Catalysis | Year: 2014

Difluoroalkylated aromatics are important structural motifs in pharmaceutical and agrochemical applications. Herein, we report their synthesis by a mild, efficient, and convenient method using visible light photoredox catalysis. A variety of unactivated aromatics were difluoroalkylated with ethyl 2-bromo-2,2-difluoroacetate (BrCF2CO2Et) in the presence of the triscyclometalated Ir complex fac-[Ir(ppy)3] under visible light irradiation at room temperature. It is shown that reaction outcomes containing the CF2CO2Et moiety can be converted to a variety of other CF2-containing aromatics, demonstrating the synthetic utility of the present method. © 2014 Wiley-VCH Verlag GmbH & Co. KGaA.

Kim W.-S.,Kyung Hee University
Journal of Chemical Engineering of Japan | Year: 2014

This study summarizes crystallization technology when using a Taylor vortex flow. A Taylor vortex is created in the gap between two co-axially positioned cylinders based on the rotation of the inner cylinder. Due to its unique periodic flow motion, a Taylor vortex has a significant influence on the processes of nucleation, growth, and agglomeration breakage in various crystallizations, including reaction recrystallization, drowning-out crystallization, and cooling crystallization. In the gas-liquid reaction crystallization of calcium carbonate, the mass transfer at the gas-liquid interface is greatly facilitated by a Taylor vortex, resulting in small crystals with a uniform size and morphology. Further, due to molecular alignment by the periodic Taylor vortex motion, the polymorphic nucleation of stable crystals is also promoted. This effect of molecular alignment by a Taylor vortex is demonstrated by the phase transformation of sulfamerazine. Furthermore, the Taylor vortex flow in a Taylor crystallizer improves the productivity of crystallization when compared with the random turbulent eddy flow in an MSMPR crystallizer. Consequently, the high performance of a Taylor crystallizer using a Taylor vortex has strong potential for application to various crystallizations. © 2014 The Society of Chemical Engineers.

Kim W.-H.,Samsung | Yeog Son J.,Kyung Hee University
Applied Physics Letters | Year: 2013

We report the influence of La substitution in epitaxial BiFeO3 thin films prepared by pulsed layer deposition on a Nb-doped SrTiO3 substrate, focusing on ferroelectric domain structure, leakage current, and multiferroic properties. Enhanced ferroelectric remanent polarization and reduced leakage current density were established via La substitution in the BiFeO3 film. Based on leakage conduction mechanism and piezoelectric force microscopy studies, this is indicative of reduced trap densities and increased domain energy. Besides that, the ferromagnetic properties were improved by the La doping as well. The possible mechanisms for the enhancement of electrical and multiferroic characteristics are extensively discussed. © 2013 AIP Publishing LLC.

Choi S.H.,Purdue University | Kim Y.L.,Purdue University | Byun K.M.,Kyung Hee University
Optics Express | Year: 2011

Taking advantage of the high impermeability property of graphene and the sharp surface plasmon resonance (SPR) curve of silver, we numerically demonstrate that SPR imaging biosensors with a graphene-on-silver substrate can be used to achieve the dramatically high sensitivity as well as to prevent silver oxidation. Results of our numerical study show that a silver substrate with a few graphene layers can significantly increase the imaging sensitivity, compared to the conventional gold-film-based SPR imaging biosensor. In particular, single layered graphene deposited on the 60-nm thick silver film amplifies the SPR imaging signal more than three times. Therefore, the proposed SPR substrate could potentially open a new possibility of SPR imaging detection for sensitive and high-throughput assessment of multiple biomolecular interactions. © 2011 Optical Society of America.

Magara T.,Kyung Hee University
Astrophysical Journal | Year: 2012

The emergence process of the magnetic field into the solar atmosphere plays an essential role in determining the configuration of the magnetic field and its activity on the Sun. This paper focuses on how much the magnetic flux contained by a flux tube emerges into the solar atmosphere, which is the key to understanding the physical mechanism of solar eruptions. By comparing a kinematic model of an emerging flux tube to a series of magnetohydrodynamic simulations, we derive the characteristics of the emergence process, showing how the process depends on the pre-emerged state of the magnetic field such as the radius of a flux tube, field strength, field-line twist, and wavelength of undulation assumed by the flux tube. We also discuss the relationship between magnetic configurations and their stability on the Sun. © 2012 The American Astronomical Society. All rights reserved.

Pae A.,Kyung Hee University
The International journal of oral & maxillofacial implants | Year: 2011

The purpose of this study was to investigate the cellular activities of MG63 osteoblast-like cells on modified titanium surfaces. MG63 osteoblast-like cells were cultured on titanium disks (n = 20 in each group) with turned, resorbable blast media (RBM)-treated, or anodized surfaces. The surfaces of commercially available implants of Osstem (Osstem Implant) were reproduced for the titanium disks. The morphology of cells cultured on these disks was examined using scanning electron microscopy. X-ray photoelectron spectroscopy (XPS) was employed for the analysis of surface chemistry. Specimens were also evaluated with an initial cell adhesion assay to compare initial adhesion, with a methyl tetrazol sulfate (MTS) assay to compare the proliferation ability, and with an alkaline phosphatase (ALP) assay to compare the differentiation ability. Statistical significance of the differences was determined using the Kruskal-Wallis test for the cell adhesion assay and analysis of variance for the MTS and ALP assays. Attached cells with more defined lamellopodia and flattened morphology were observed on the anodized and RBM surfaces than on the turned surfaces. The titanium surfaces were all oxidized as titanium oxide and polluted by carbon determinants, as determined by XPS. Anodized titanium surfaces exhibited calcium and phosphorus peaks. Initial cell attachment activity, cell proliferation activity, and ALP activity were higher on the anodized surfaces than on the other surfaces. Cell differentiation on the anodized surfaces at culture day 10 was significantly higher (P < .05) than on the other surfaces. Surface treatment by anodization may improve initial attachment of cells, proliferation ability, and differentiation activity, which play important roles in providing better osseointegration of implants. More rapid and stronger osseointegration of implants may make it possible to offer the best anchorage and shorten the healing time required prior to functional loading.

Jung U.,Dongguk University | Seo D.W.,Kyung Hee University
Decision Support Systems | Year: 2010

As countries strive to become more efficient in investing limited resources in various national R&D projects, the evaluation of project has become increasingly important. However, due to the heterogeneity of the objectives of national R&D programs, few studies have been conducted on comparing programs on the basis of performance. This study explores the application of the analytic network process (ANP) approach for the evaluation of R&D projects that are elements of programs with heterogeneous objectives. The ANP produced the final priorities of projects with respect to benefits and costs when there are interdependencies between programs and evaluation criteria. The paper provides value to practitioners by providing a generic model for project evaluation. For researchers, the paper demonstrates a novel application of ANP under specific situation of heterogeneous objectives. The ANP approach is tested against empirical data drawn from R&D projects sponsored by the Korean government. © 2010 Elsevier B.V. All rights reserved.

OBJECTIVES: Signal transducer and activator of transcription 3 (STAT3) is an oncogenic transcription factor implicated in carcinogenesis. Here, we investigated the role of morusin, the major prenylflavonoid, isolated from Chinese herbal medicine in abrogating the constitutive STAT3 activation in human pancreatic tumor cells. METHODS: The effect of morusin on STAT3 activation, associated protein kinases, STAT3-regulated gene products, cellular proliferation, and apoptosis was examined. RESULTS: Morusin specifically inhibited constitutive STAT3 activation both at tyrosine residue 705 and serine residue 727 in 4 pancreatic tumor cells. The inhibition of STAT3 was mediated through the suppression of activation of upstream JAK1, JAK2, and c-Src kinases. Morusin led to the accumulation of the cells in different phases of the cell cycle and caused induction of apoptosis and loss of mitochondrial membrane potential. Morusin downregulated the expression of various STAT3-regulated gene products; this correlated with induction of caspase-3 activation and anti-invasive effects. Treatment with the protein tyrosine phosphatase inhibitor pervanadate reversed the morusin-induced downregulation of STAT3, thereby suggesting the involvement of a protein tyrosine phosphatase. CONCLUSIONS: Morusin is a novel blocker of STAT3 activation and thus may have potential in negative regulation of growth and metastasis of pancreatic tumor cells. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.

Heo S.H.,Kyung Hee University | Lee S.-H.,Seoul National University
Journal of the Neurological Sciences | Year: 2010

Background: Uric acid has been known to exert neuroprotective effects by acting as a free radical scavenger; however, several observational studies indicated that high levels of serum uric acid increased the risk of cardiovascular events or stroke. We sought to determine whether increased levels of uric acid are associated with the presence of silent brain infarction (SBI). Methods: We recruited a consecutive series of non-stroke individuals who visited the Healthcare System in our hospital and underwent brain MRI (n = 1577). We conducted intensive interviews and laboratory examinations, including serum uric acid. We examined associations between SBI and vascular risk factors including uric acid by controlling possible confounders. Results: Of the 1577 subjects recruited, 921 were men and 656 were women, and the uric acid level was much higher in the men (6.3 ± 1.3) than in the women (4.7 ± 1.0). There was a strong dose-response relationship between the quartiles of uric acid and the presence of SBI in women (p = 0.001), but not in men. Multivariable analysis showed that the highest quartile of uric acid level was an independent risk factor for the presence of SBI in total patients (adjusted OR, 1.79; 95% CI, 1.11-2.91). However, this association remained significant in women (adjusted OR, 2.64; 95% CI, 1.17-5.91), but not in men. Conclusions: Our results suggest that an increased level of uric acid may be a risk factor for the presence of SBI. Serum uric acid level might be a good serum marker of underlying SBI or future stroke, especially in women. © 2010 Elsevier B.V. All rights reserved.

Kleinman D.L.,Kyung Hee University | Kleinman D.L.,University of Wisconsin - Madison | Suryanarayanan S.,University of Wisconsin - Madison
Science Technology and Human Values | Year: 2013

This article utilizes the ongoing debates over the role of certain agricultural insecticides in causing Colony Collapse Disorder (CCD)-the phenomenon of accelerated bee die-offs in the United States and elsewhere-as an opportunity to contribute to the emerging literature on the social production of ignorance. In our effort to understand the social contexts that shape knowledge/nonknowledge production in this case, we develop the concept of epistemic form. Epistemic form is the suite of concepts, methods, measures, and interpretations that shapes the ways in which actors produce knowledge and ignorance in their professional/intellectual fields of practice. In the CCD controversy, we examine how the (historically influenced) privileging of certain epistemic forms intersects with the social dynamics of academic, regulatory, and corporate organizations to lead to the institutionalization of three interrelated and overlapping types of ignorance. We consider the effects of these types of ignorance on US regulatory policy and on the lives of different stakeholders. © The Author(s) 2012.

Ngo T.-A.,Ho Chi Minh City University of Technology | Kim J.,Kyung Hee University | Kim S.-S.,Kangwon National University
Journal of Industrial and Engineering Chemistry | Year: 2013

In this study, the central composite rotatable design (CCRD) was employed to investigate the effects of the feedstock feed rate, biomass particle size, pyrolysis temperature, and residence time on the fast pyrolysis of palm kernel cake. A mathematical model for the liquid product yield was developed and applied to obtain a maximum yield of 49.5. wt%. The GC-MS analyses of the bio-oils at the two different temperatures of 400 and 500. °C showed that they were a complex mixture composed of mostly oxygenated compounds including β-D-allose, derivatives of furan and phenol, and a considerable amount of fatty acids. © 2012 The Korean Society of Industrial and Engineering Chemistry.

Barr S.M.,University of Delaware | Kim J.E.,Kyung Hee University
Physical Review Letters | Year: 2014

The serious cosmological problems created by the axion-string-axion-domain-wall system in standard axion models are alleviated by positing the existence of a new confining force. The instantons of this force can generate an axion potential that erases the axion strings long before QCD effects become important, thus preventing QCD-generated axion walls from ever appearing. Axion walls generated by the new confining force would decay so early as not to contribute significantly to the energy in axion dark matter. © 2014 American Physical Society.

Lee M.,Kyung Hee University | Choi M.-S.,Korea University
Physical Review Letters | Year: 2014

We investigate the mesoscopic resistor-capacitor circuit consisting of a quantum dot coupled to spatially separated Majorana fermion modes in a chiral topological superconductor. We find substantially enhanced relaxation resistance due to the nature of Majorana fermions, which are their own antiparticles and are composed of particle and hole excitations in the same abundance. Further, if only a single Majorana mode is involved, the zero-frequency relaxation resistance is completely suppressed due to a destructive interference. As a result, the Majorana mode opens an exotic dissipative channel on a superconductor which is typically regarded as dissipationless due to its finite superconducting gap. © 2014 American Physical Society.

Choi E.M.,Kyung Hee University
Experimental and Toxicologic Pathology | Year: 2012

The protective effect of quercitrin on the response of osteoblastic MC3T3-E1 cells to oxidative stress was evaluated. Osteoblasts were incubated with H 2O 2 and/or quercitrin, and markers of osteoblast function and oxidative damage were examined. Quercitrin treatment reversed the cytotoxic effect of H 2O 2 significantly (P<0.05). This effect was blocked by ICI182780 and LY294002, suggesting that quercitrin's effect might be involved in estrogen action and results from PI3K mediated signaling pathway. Pretreatment of quercitrin increased collagen content, alkaline phosphatase (ALP) activity, and calcium deposition of osteoblasts compared with H 2O 2 treated cells and these effects were blocked by ERKs and p38 mitogen-activated protein kinases (MAPKs) inhibitors such as PD98059 and SB203580, respectively. These suggest that quercitrin-induced protective effect against osteoblast dysfunction by oxidative stress is associated with increased activation of ERKs and p38 MAPK. Pretreatment with quercitrin also reduced the increase in bone-resorbing factor, receptor activator of nuclear factor-kB ligand (RANKL) and oxidative damage markers (malondialdehyde, protein carbonyl, and nitrotyrosine) induced by H 2O 2. These results suggest that quercitrin may be protective against H 2O 2-induced dysfunction in osteoblasts. © 2010 Elsevier GmbH.

Kim D.,Kyung Hee University
IEEE Network | Year: 2010

High-quality services will be the most important competitive edge in next-generation Internet services such as the broadband Internet access market, which is now reaching a saturation point in many countries. This article presents an application of the House of Quality framework combined with the Analytic Hierarchy Process method for the service quality improvement of network services. The HoQ, which is at the core of general quality management programs, constitutes a useful tool to evaluate and organize users¿ quality of experience and engineering characteristics that are related to the network performance and quality of service. Furthermore, the QoE and ECs are combined together in the HoQ framework in order to present an explicit direction for quality improvement. We also calibrate the generic HoQ model by employing the AHP method in measuring the relationships between the QoE and ECs in a quantitative manner. Through a case study on DSL services, we illustrate the applicability and usefulness of the proposed framework for QoE improvement. For example, the case study reveals that soft factors, including dimensioning and configuring the networks, outweigh hard ones. This finding runs somehow counter to empirical wisdom that DSL service quality heavily depends on hard factors such as devices and lines. © 2010 IEEE.

Chen H.,Zhejiang University | Gottweis H.,Kyung Hee University
Bioethics | Year: 2013

The paper looks in detail at patients that were treated at one of the most discussed companies operating in the field of untried stem cell treatments, Beike Biotech of Shenzhen, China. Our data show that patients who had been treated at Beike Biotech view themselves as proactively pursuing treatment choices that are not available in their home countries. These patients typically come from a broad variety of countries: China, the United Kingdom, the United States, South Africa and Australia. Among the patients we interviewed there seemed to be both an awareness of the general risks involved in such experimental treatments and a readiness to accept those risks weighed against the possible benefits. We interpret this evidence as possibly reflecting the emergence of risk-taking patients as 'consumers' of medical options as well as the drive of patients to seek treatment options in the global arena, rather than being hindered by the ethical and regulatory constraints of their home countries. Further, we found that these patients tend to operate in more or less stable networks and groups in which they interact and cooperate closely and develop opinions and assessments of available treatment options for their ailments. These patients also perform a multiple role as patients, research subjects, and research funders because they are required to pay their way into treatment and research activities. This new social dynamics of patienthood has important implications for the ethical governance of stem cell treatments. © 2011 Blackwell Publishing Ltd.

Lee J.,Seoul National University | Choi Y.-Y.,Kyung Hee University
Astrophysical Journal | Year: 2015

We report a detection of the effect of the large-scale velocity shear on the spatial distributions of the galactic satellites around the isolated hosts. Identifying the isolated galactic systems, each of which consists of a single host galaxy and its satellites, from the Seventh Data Release of the Sloan Digital Sky Survey and reconstructing linearly the velocity shear field in the local universe, we measure the alignments between the relative positions of the satellites from their isolated hosts and the principal axes of the local velocity shear tensors projected onto the plane of sky. We find a clear signal that the galactic satellites in isolated systems are located preferentially along the directions of the minor principal axes of the large-scale velocity shear field. Those galactic satellites that are spirals, are brighter, are located at distances larger than the projected virial radii of the hosts, and belong to the spiral hosts yield stronger alignment signals, which implies that the alignment strength depends on the formation and accretion epochs of the galactic satellites. It is also shown that the alignment strength is quite insensitive to the cosmic web environment, as well as the size and luminosity of the isolated hosts. Although this result is consistent with the numerical finding of Libeskind et al. based on an N-body experiment, owing to the very low significance of the observed signals, it remains inconclusive whether or not the velocity shear effect on the satellite distribution is truly universal. © 2015. The American Astronomical Society. All rights reserved.

OBJECTIVE:: Epidemiological evidence indicates that excess fat may be beneficial for bone health, offering protective effects against the onset of postmenopausal osteoporosis. Experimental data suggest that this link might be due to the direct effect of adipokines on bone tissue. Confirmatory evidence of this association, however, remains limited. METHODS:: The levels of a panel of selected adipokines including interleukin (IL)-6, -8, -1β, adipsin, lipocalin-2/neutrophil gelatinase-associated ipocalin, tumor necrosis factor alpha, monocyte chemoattractant protein-1, plasminogen activator inhibitor-1, hepatocyte growth factor, resistin, leptin, and adiponectin in a group of osteopenic and osteoporotic postmenopausal women were compared with those of unaffected women (n?=?127). RESULTS:: Univariate analysis revealed that leptin and adiponectin were significantly correlated with bone mineral density (BMD). In particular, leptin was positively associated with BMD of the spine (r?=?0.22, P?

Kato H.,University of Tsukuba | Onda Y.,University of Tsukuba | Tanaka Y.,Kyung Hee University
Geomorphology | Year: 2010

In this study, two small experimental catchments were selected in semi-arid grassland in Mongolia. The Kherlen-bayan Ulaan (KBU) catchment has been subjected to intensive grazing as a wintering shelter for domestic livestock animals, and the number of livestock animals in the Baganuur (BGN) catchment has been increasing over the last few decades. The rates and patterns of soil erosion within the catchments were estimated based on cesium-137 (137Cs) and lead-210 (210Pbex) inventories in bulk soil core samples. The medium-term (~ 40 years) soil erosion rates based on the 137Cs measurements indicated that annual soil loss from the KBU catchment was approximately three times greater than that from the BGN catchment. The 137Cs-derived rates and patterns of soil erosion indicated that soil in the KBU catchment was susceptible to surface erosion, with facilitated transport of eroded sediment to the catchment outlet. The 210Pbex-derived soil erosion rates were generally greater than those derived from 137Cs in both catchments. If we assume that the soil erosion rate has been increasing with increasing domestic livestock numbers, the most plausible explanation is that the 210Pbex-derived estimates represent recent increases in soil erosion. Furthermore, the 210Pbex/137Cs inventory ratio showed a tendency to increase with downslope distance on the eroded hillslope in the BGN catchment. Assuming that the increase in inventory ratio is a result of constant fallout input of 210Pbex on the eroded sediment during its transportation along the hillslope, the 210Pbex inventory may not be suitable to estimate soil erosion rates at sites where downslope movement of sediment is slow. Further discussion regarding interpretation of 210Pbex-derived soil loss is required, and the applicability of the 210Pbex technique on semi-arid hillslopes remains to be determined. © 2009 Elsevier B.V. All rights reserved.

Lee S.,Kyung Hee University
Bulletin of the Korean Chemical Society | Year: 2011

We present a brief review for theoretical/computational studies of proton transfer processes of some simple biomolecules promoted by microsolvating water molecules. Focus is given on the relative stability of the canonical vs. zwitterionic forms of amino acids, tautomeric forms of the DNA base adenine, and the biologically active vs. inactive forms of nicotine. The biochemical implications of these findings are also discussed.

Chiani M.,University of Bologna | Win M.Z.,Massachusetts Institute of Technology | Shin H.,Kyung Hee University
IEEE Transactions on Information Theory | Year: 2010

Multiple-input multiple-output (MIMO) systems are being considered as one of the key enabling technologies for future wireless networks. However, the decrease in capacity due to the presence of interferers in MIMO networks is not well understood. In this paper, we develop an analytical framework to characterize the capacity of MIMO communication systems in the presence of multiple MIMO co-channel interferers and noise. We consider the situation in which transmitters have no channel state information, and all links undergo Rayleigh fading. We first generalize the determinant representation of hypergeometric functions with matrix arguments to the case when the argument matrices have eigenvalues of arbitrary multiplicity. This enables the derivation of the distribution of the eigenvalues of Gaussian quadratic forms and Wishart matrices with arbitrary correlation, with application to both single-user and multiuser MIMO systems. In particular, we derive the ergodic mutual information for MIMO systems in the presence of multiple MIMO interferers. Our analysis is valid for any number of interferers, each with arbitrary number of antennas having possibly unequal power levels. This framework, therefore, accommodates the study of distributed MIMO systems and accounts for different spatial positions of the MIMO interferers. © 2009 IEEE.

Hoo Lee J.,Jeju National University | Hyung Kim Y.,Kyung Hee University
Brazilian Journal of Infectious Diseases | Year: 2012

Background: Since healthcare-associated pneumonia (HCAP) is heterogeneous, clinical characteristics and outcomes are different from region to region. There can also be differences between HCAP patients hospitalized in secondary or tertiary hospitals. This study aimed to evaluate the clinical characteristics of HCAP patients admitted into secondary community hospitals. Methods: This was a retrospective study conducted in patients with HCAP or community-acquired pneumonia (CAP) hospitalized in two secondary hospitals between March 2009 and January 2011. Results: Of a total of 303 patients, 96 (31.7%) had HCAP. 42 patients (43.7%) resided in a nursing home or long-term care facility, 36 (37.5%) were hospitalized in an acute care hospital for ≥ 2 days within 90 days, ten received outpatient intravenous therapy, and eight attended a hospital clinic or dialysis center. HCAP patients were older. The rates of patients with CURB-65 scores of 3 or more (22.9% vs. 9.1%; p = 0.001) and PSI class IV or more (82.2% vs. 34.7%; p < 0.001) were higher in the HCAP group. Drug-resistant pathogens were more frequently detected in the HCAP group (23.9% vs. 0.4%; p < 0.001). However, Streptococcus pneumoniae was the most common pathogen in both groups. The rates of antibiotic change, use of inappropriate antibiotics, and failure of initial antibiotic therapy in the HCAP group were significantly higher. Although the overall survival rate of the HCAP group was significantly lower (82.3% vs. 96.8%; p < 0.001), multivariate analyses failed to show that HCAP itself was a prognostic factor for mortality (p = 0.826). Only PSI class IV or more was associated with increased mortality (p = 0.005). Conclusions: HCAP should be distinguished from CAP because of the different clinical features. However, the current definition of HCAP does not appear to be a prognostic for death. In addition, the use of broad-spectrum antibiotics for HCAP should be reassessed because S. pneumoniae was most frequently identified even in HCAP patients. © 2012 Elsevier Editora Ltda.

Park H.S.,Kyung Hee University | Choi B.G.,KAIST | Hong W.H.,KAIST | Jang S.-Y.,Kookmin University
Journal of Physical Chemistry C | Year: 2012

Nanohybrids consisting of single-walled carbon nanotubes (SWCNTs) and a conductive block copolymer, perchlorate-doped poly(3,4-ethylenedioxythiophene)- block-poly(ethyleneoxide) (P-PEDOT-b-PEO), were successfully prepared. Individual exfoliation of SWCNTs and high solution processability were simultaneously achieved in the supramolecular assembly. The assembly at the molecular level was driven by the interfacial interaction between SWCNT walls and the PEDOT block, as characterized by various spectroscopic analyses (UV-Vis, FT-IR, PL, and Raman). The exfoliation of SWCNTs and the solubility of the nanohybrids, which are facilitated by the soluble PEO block, were confirmed by Raman spectroscopy and a range of other microscopy techniques (AFM, TEM, and SEM). Flexible transparent conductive films of the nanohybrids were fabricated using a vacuum-assisted filtration method. The films displayed high electrical conductivity with good mechanical integrity due to the strong interaction between the SWCNT and the conductive polymer. The strategy described here opens up promising possibilities for the fabrication of CNT/conjugated polymer hybrids as well as for their use in flexible electronics. © 2012 American Chemical Society.

Lee S.H.,Kyung Hee University
Interventional neuroradiology : journal of peritherapeutic neuroradiology, surgical procedures and related neurosciences | Year: 2011

Therapeutic strategies for unruptured aneurysms in elective procedures must be carefully planned with respect to safety. We describe the case of a patient who presented with an unruptured aneurysm associated with a double origin of the posterior inferior cerebellar artery (DOPICA), a rare variant of aberrant origin. A three-dimensional rotational angiogram clearly showed that the aneurysm incorporated the origin of the DOPICA caudal channel, which was more dominant than the cranial one. The aneurysm was completely obliterated using detachable coils after a balloon occlusion test (BOT) of the caudal channel was conducted to confirm the tolerance of the patient following sudden interruption of the more prominent flow coming from the caudal channel of the DOPICA. This report affirms the need to suspect anomalies associated with a DOPICA that predispose to intracranial aneurysms and highlights the potential role of a BOT in pretreatment hemodynamic evaluations of unusual aneurysms accompanying a particular developmental anomaly.

Jun J.-K.,Wooridul Spine Hospital | Kim S.-M.,Kyung Hee University
Journal of Korean Neurosurgical Society | Year: 2012

Objective: The aim of this study was to determine whether single nucleotide polymorphisms (SNPs) of fibroblast growth factor (FGF) 2 gene and fibroblast growth factor receptor (FGFR) genes are associated with ossification of the posterior longitudinal ligament (OPLL). Methods: A total of 157 patients with OPLL and 222 controls were recruited for a case control association study investigating the relationship between SNPs of FGF2, FGFR1, FGFR2 and OPLL. To identify the association among polymorphisms of FGF2 gene, FGFR1, FGFR2 genes and OPLL, the authors genotyped 9 SNPs of the genes (FGF2: rs1476217, rs308395, rs308397, and rs3747676; FGFR1: rs13317 and rs2467531; FGFR2: rs755793, rs1047100, and rs3135831) using direct sequencing method. SNPs data were analyzed using the SNPStats, SNPAnalyzer, Haploview, and Helixtree programs. Results: Of the SNPs, a SNP (rs13317) in FGFR1 was significantly associated with the susceptibility of OPLL in the codominant (odds ratio=1.35, 95% confidence interval=1.01-1.81, p=0.048) and recessive model (odds ratio=2.00, 95% confidence interval=1.11-3.59, p=0.020). The analysis adjusted for associated condition showed that the SNP of rs1476217 (p=0.03), rs3747676 (p=0.01) polymorphisms in the FGF2 were associated with diffuse idiopathic skeletal hyperostosis (DISH) and rs1476217 (p=0.01) in the FGF2 was associated with ossification of the ligament flavum (OLF). Conclusion: The results of the present study revealed that an FGFR1 SNP was significantly associated with OPLL and that a SNP in FGF2 was associated with conditions that were comorbid with OPLL (DISH and OLF). © 2012 The Korean Neurosurgical Society.

BACKGROUND: Osteopontin (OPN) is one of important molecular targets in cancer progression, metastasis as a calcium-binding, extracellular-matrix-associated protein of the small integrin-binding ligand and, N-linked glycoprotein. In the present study, anti-metastatic mechanism of ethanol extracts of Ocimum sanctum (EEOS) was elucidated on OPN enhanced metastasis in NCI-H460 non- small cell lung cancer cells.METHODS: Cell viability was measured by MTT assay. Adhesion and invasion assays were carried out to see that EEOS inhibited cell adhesion and invasion in OPN treated and non-treated NCI-H 460 cells. RT-PCR was used to determine the mRNA levels of uPA, uPAR, and EGFR.RESULTS: EEOS significantly inhibited cell adhesion and invasion in OPN treated and non treated NCI-H460 cells, though EEOS did not show any toxicity up to 200 μg/ml. EEOS effectively attenuated the expression of OPN and CD44 and also OPN activated the expression of CD44 in NCI-H460 cells. In addition, EEOS effectively suppressed the expression of phosphatidylinositide 3-kinases (PI3K) and cyclooxygenase 2 (COX-2) and the phosphorylation of Akt at protein level in OPN treated NCI-H460 cells. Also, EEOS significantly attenuated the expression of urokinase plasminogen activator (uPA), its receptor (uPAR) and epidermal growth factor receptor (EGFR) at mRNA level and reduced vascular endothelial growth factor (VEGF) production and MMP-9 activity in OPN treated NCI-H460 cells. Furthermore, PI3K/Akt inhibitor LY294002 enhanced anti-metastatic potential of EEOS to attenuate the expression of uPA and MMP-9 in OPN treated NCI-H 460 cells.CONCLUSION: Overall, our findings suggest that anti-metastatic mechanism of EEOS is mediated by inhibition of PI3K/Akt in OPN treated NCI-H460 non-small cell lung cancer cells.

Hunter W.C.,Kyung Hee University
International Journal of Tourism Research | Year: 2015

The demilitarized zone (DMZ) and Dokdo mark South Korea borders with North Korea and Japan respectively. Each borderland is a socially constructed symbolic cultural landscape shaped in part by tourism. In this study, a sample of 2202 online images was inspected using content-semiotic analysis to understand how visual representation of border tourism works. It was found that visitors via social media and government censorship play major roles in constructing representations of (i) alienated borders with iconic war heritage attractions at the DMZ and (ii) an alienated and isolated Dokdo. Both borders highlight patriotic/nationalistic 'flagging' and the gaze across. © 2013 John Wiley & Sons, Ltd.

BACKGROUND: Though herbal medicines have been used for cancer prevention and treatment, their scientific evidences still remain unclear so far. Thus, complementary and alternative medicine (CAM) project has been actively executed to reveal the scientific evidences in the USA and other countries. In the present study, we elucidated antitumor mechanism of Chijongdan, an oriental prescription of Rhus verniciflua, processed Panax ginseng, Persicaria tinctoria and Realgar, that has been traditionally applied for cancer treatment in Korea.METHODS: Chijongdan was prepared with extracts of Rhus verniciflua, processed Panax ginseng, Persicaria tinctoria and processed Realgar. The cytotoxicity of Chijongdan was measured by MTT colorimetric assay. Cell cycle analysis was performed by FACS. Western blot was performed to see the apoptosis related proteins.RESULTS: Chijongdan significantly exerted cytotoxicity in A549, H460 and H1299 non-small cell lung carcinoma (NSCLC) cells by MTT assay and also increased the number of ethidium homodimer positively stained cells in A549 NSCLC cells. Also, cell cycle analysis showed that Chijongdan increased sub-G1 population in a concentration dependent manner in A549 cells. In addition, Western blotting revealed that Chijongdan activated cleaved PARP, and caspase 9/3, while attenuated the expression of survival genes such as Bcl-2, Bcl-XL and survivin in A549 cells. Furthermore, Chijongdan suppressed the expression of ribosomal biogenesis related proteins such as upstream binding factor (UBF), Fibrillarin, NPM (B23) and Importin-7 (IPO7) and conversely pan-caspase inhibitor Z--VAD-FMK reversed the apoptotic ability of Chijongdan to cleave PARP and caspase 3 and attenuate the expression of UBF and Fibrillarin in A549 cells.CONCLUSIONS: These findings suggest that Chijongdan induces apoptosis and inhibits ribosomal biogenesis proteins via caspase activation.

Ho M.Y.,University of Cambridge | D'Souza N.,UK Defence Evaluation and Research Agency | Migliorato P.,University of Cambridge | Migliorato P.,Kyung Hee University
Analytical Chemistry | Year: 2012

Electrochemical impedance spectroscopy (EIS) is used to detect 2,4,6-trinitrotoluene (TNT) in a novel sandwiched structure which relies on the specific interactions between (i) primary amine with TNT and (ii) TNT and anti-TNT aptamer. With pure targets, the assay has a sensitivity of 10 -14 M, a dynamic range of 10 -14-10 -3 M, and employs a small sample volume (25 μL). The method's sensitivity is comparable to state of the art optical methods with the added advantages of electrochemical detection, which can be easily miniaturized and implemented into a hand-held device. © 2012 American Chemical Society.

Kim J.E.,Kyung Hee University
Physical Review Letters | Year: 2013

We show that the hierarchically small μ term in supersymmetric theories is a consequence of two identical pairs of Higgs doublets taking a democratic form for their mass matrix. We briefly discuss the discrete symmetry S 2×S2 toward the democratic mass matrix. Then, we show that there results an approximate Peccei-Quinn symmetry and hence the value μ is related to the axion decay constant. © 2013 American Physical Society.

Kim S.S.,Chonnam National University | Park Y.-K.,Kyung Hee University
Cancer and Metastasis Reviews | Year: 2014

Osteosarcoma is the most common malignant bone tumor in children and characterized by aggressive biologic behavior of metastatic propensity to the lung. Change of treatment paradigm brings survival benefit; however, 5-year survival rate is still low in patients having metastastatic foci at diagnosis for a few decades. Metastasis-associated protein (MTA) family is a group of ubiquitously expressed coregulators, which influences on tumor invasiveness or metastasis. MTA1 has been investigated in various cancers including osteosarcoma, and its overexpression is associated with high-risk features of cancers. In this review, we described various molecular studies of osteosarcoma, especially associated with MTA1. © 2014, Springer Science+Business Media New York.

Lee G.-H.,Seoul National University | Park C.,Korea Institute for Advanced Study | Lee M.G.,Seoul National University | Choi Y.-Y.,Kyung Hee University
Astrophysical Journal | Year: 2012

We investigate the dependence of the occurrence of bars in galaxies on galaxy properties and environment. We use a volume-limited sample of 33,391 galaxies brighter than Mr = -19.5 + 5logh at 0.02 ≤ z ≤ 0.05489, drawn from the Sloan Digital Sky Survey Data Release 7. We classify the galaxies into early and late types, and identify bars by visual inspection. Among 10,674 late-type galaxies with axis ratio b/a > 0.60, we find 3240 barred galaxies (f bar = 30.4%) which divide into 2542 strong bars (f SB1 = 23.8%) and 698 weak bars (f SB2 = 6.5%). We find that f SB1 increases as u - r color becomes redder and that it has a maximum value at intermediate velocity dispersion (σ ≃150kms -1). This trend suggests that strong bars are dominantly hosted by intermediate-mass systems. Weak bars prefer bluer galaxies with lower mass and lower concentration. In the case of strong bars, their dependence on the concentration index appears only for massive galaxies with σ > 150kms-1. We also find that f bar does not directly depend on the large-scale background density when other physical parameters (u - r color or σ) are fixed. We discover that f SB1 decreases as the separation to the nearest neighbor galaxy becomes smaller than 0.1 times the virial radius of the neighbor regardless of neighbor's morphology. These results imply that strong bars are likely to be destroyed during strong tidal interactions and that the mechanism for this phenomenon is gravitational and not hydrodynamical. The fraction of weak bars has no correlation with environmental parameters. We do not find any direct evidence for environmental stimulation of bar formation. © 2012. The American Astronomical Society. All rights reserved.

Lee J.-H.,Pohang University of Science and Technology | Jeong Y.K.,Pohang University of Science and Technology | Park J.H.,Pohang University of Science and Technology | Oak M.-A.,Pohang University of Science and Technology | And 3 more authors.
Physical Review Letters | Year: 2011

SmFeO3, a family of centrosymmetric rare-earth orthoferrites, is known to be nonferroelectric. However, we have found that SmFeO3 is surprisingly ferroelectric at room temperature with a small polarization along the b axis of Pbnm. First-principles calculations indicate that the canted antiferromagnetic ordering with two nonequivalent spin pairs is responsible for this extraordinary polarization and that the reverse Dzyaloshinskii-Moriya interaction dominates over the exchange-striction mechanism in the manifestation of the improper ferroelectricity. SmFeO3 further exhibits an interesting phenomenon of spontaneous magnetization reversal at cryogenic temperatures. This reversal is attributed to the activation of the Sm-spin moment which is antiparallel to the Fe-spin moment below ∼5K. © 2011 American Physical Society.

Yang S.J.,Chonnam National University | Lim Y.,Kyung Hee University
Metabolism: Clinical and Experimental | Year: 2014

Objective Resveratrol (RSV) regulates NAD bioavailability and sirtuin-related metabolism, which relates to aging, metabolic syndrome and non-alcoholic fatty liver disease. The purpose of this study was to investigate the effects of resveratrol on hepatic metaflammation in a rodent model of high-fat (HF) diet-induced obesity (DIO). Materials/Methods DIO was induced in a subset of mice given an HF diet (45% kcal fat). After 6 weeks of HF diet feeding, RSV was delivered via an osmotic pump for 4 weeks. The experimental groups were as follows: 1) lean control fed with a standard diet, 2) HF diet-induced obese control, and 3) HF-RSV (8 mg/kg/day). After 4 weeks of each treatment, blood and liver tissues were collected and the indices of glucose control, serum and liver triglyceride (TG), sirtuin pathway, inflammation, and NOD-like receptor family, pryin domain containing 3 (NLRP3) inflammasome were analyzed. Results Body weight and food intake were not altered by administering resveratrol. Glucose control was impaired, and serum and liver TG levels were increased by the HF diet. Hepatic inflammation was aggravated in mice fed with the HF diet, as shown by the increased levels of the pro-inflammatory markers interleukin-1 (IL-1), IL-6 and tumor necrosis factor-alpha in the liver. However, resveratrol administration significantly improved glucose control, and serum and liver TG contents. Also, resveratrol treatment reduced the levels of the pro-inflammatory markers. These improvements were accompanied by alterations in sirtuin pathway and NLRP3 inflammasome activation. Conclusion These results demonstrate that resveratrol ameliorates hepatic metaflammation, accompanied by alterations in NLRP3 inflammasome. © 2014 Elsevier Inc. All rights reserved.

Kim D.H.,Dong - A University | Im Y.J.,Kyung Hee University
European Journal of Oncology Nursing | Year: 2015

Purpose: To examine the psychosocial problems of childhood cancer survivors in Korea and investigate whether such problems are influenced by family management style. Methods: Family members of 158 childhood cancer survivors answered a questionnaire on demographic and illness characteristics, described psychosocial problems in their children using the Pediatric Symptom Checklist (PSC), and completed the Family Management Measure (FaMM). Results: Perceived economic status and all six subscales of the FaMM were significantly correlated with children's psychosocial problems. In a multiple regression model, the Family Life Difficulty and Parental Mutuality scales of the FaMM were each independent predictors of psychosocial problems in young cancer survivors. Conclusions: A detailed care plan designed to (1) promote balance between the management of a child's condition and normal family life and (2) encourage parents to share their feelings with one another and provide mutual support should be required to improve psychosocial outcomes for childhood cancer survivors. © 2014 Elsevier Ltd.

Chun Y.S.,Kyung Hee University
Clinics in orthopedic surgery | Year: 2010

Calcific myonecrosis is a rare late post-traumatic condition, in which a single muscle is replaced by a fusiform mass with central liquefaction and peripheral calcification. Compartment syndrome is suggested to be the underlying cause. The resulting mass may expand with time due to recurrent intralesional hemorrhage into the chronic calcified mass. A diagnosis may be difficult due to the long time between the original trauma and the symptoms of calcific myonecrosis. We encountered a 53-year-old male patient diagnosed with calcific myonecrosis in the lower leg. We report the case with a review of the relevant literature.

Wang J.,Kyung Hee University
Sensors (Basel, Switzerland) | Year: 2010

Energy efficiency and balancing is one of the primary challenges for wireless sensor networks (WSNs) since the tiny sensor nodes cannot be easily recharged once they are deployed. Up to now, many energy efficient routing algorithms or protocols have been proposed with techniques like clustering, data aggregation and location tracking etc. However, many of them aim to minimize parameters like total energy consumption, latency etc., which cause hotspot nodes and partitioned network due to the overuse of certain nodes. In this paper, a Distance-based Energy Aware Routing (DEAR) algorithm is proposed to ensure energy efficiency and energy balancing based on theoretical analysis of different energy and traffic models. During the routing process, we consider individual distance as the primary parameter in order to adjust and equalize the energy consumption among involved sensors. The residual energy is also considered as a secondary factor. In this way, all the intermediate nodes will consume their energy at similar rate, which maximizes network lifetime. Simulation results show that the DEAR algorithm can reduce and balance the energy consumption for all sensor nodes so network lifetime is greatly prolonged compared to other routing algorithms.

Han C.Y.,Kyung Hee University
Computer Aided Geometric Design | Year: 2010

Monotone helical curves are polynomial helices whose unit tangent maintains a fixed sense of rotation about an axis. We investigate the interpolation of geometric Hermite data consisting of end points, tangents, and curvatures by monotone helical quintics. Based on the Hopf map model for spatial Pythagorean-hodograph curves, which subsume polynomial helices, we show that the geometric Hermite interpolation can be determined by solving a certain univariate polynomial equation of degree twelve. © 2010 Elsevier B.V. All rights reserved.

Cho J.,Pohang University of Science and Technology | Lee J.,Kyung Hee University
Expert Systems with Applications | Year: 2013

As the number of new products developed by new technologies has increased, the importance of the commercialization of new technology products has become crucial to manufactures in the successful delivery of valuable new products and services. This study classified success factors for commercialization of new products and analyzed which factors should be primarily considered. Based on the literature review and Delphi method, we identified four decision areas and further prioritized the sixteen factors under a hierarchy model structured by fuzzy AHP (analytic hierarchy process) approach. The FAHP is conducted by 111 R&D and business experts working at the world's major players in machinery industry; using the priorities of success factors derived by FAHP, we devise an example of commercialization assessment model. The paper drives the assessment initiatives of the new product development in manufactures and provides them with practical implications about the commercialization of new technology product. © 2013 Elsevier Ltd. All rights reserved.

Soh Y.S.,California Institute of Technology | Quek T.Q.S.,Singapore University of Technology and Design | Kountouris M.,Supelec | Shin H.,Kyung Hee University
IEEE Journal on Selected Areas in Communications | Year: 2013

With the exponential increase in mobile internet traffic driven by a new generation of wireless devices, future cellular networks face a great challenge to meet this overwhelming demand of network capacity. At the same time, the demand for higher data rates and the ever-increasing number of wireless users led to rapid increases in power consumption and operating cost of cellular networks. One potential solution to address these issues is to overlay small cell networks with macrocell networks as a means to provide higher network capacity and better coverage. However, the dense and random deployment of small cells and their uncoordinated operation raise important questions about the energy efficiency implications of such multi-tier networks. Another technique to improve energy efficiency in cellular networks is to introduce active/sleep (on/off) modes in macrocell base stations. In this paper, we investigate the design and the associated tradeoffs of energy efficient cellular networks through the deployment of sleeping strategies and small cells. Using a stochastic geometry based model, we derive the success probability and energy efficiency in homogeneous macrocell (single-tier) and heterogeneous K-tier wireless networks under different sleeping policies. In addition, we formulate the power consumption minimization and energy efficiency maximization problems, and determine the optimal operating regimes for macrocell base stations. Numerical results confirm the effectiveness of switching off base stations in homogeneous macrocell networks. Nevertheless, the gains in terms of energy efficiency depend on the type of sleeping strategy used. In addition, the deployment of small cells generally leads to higher energy efficiency but this gain saturates as the density of small cells increases. In a nutshell, our proposed framework provides an essential understanding on the deployment of future green heterogeneous networks. © 1983-2012 IEEE.

Jeong H.,Gwangju Institute of Science and Technology | Song H.,Gwangju Institute of Science and Technology | Pak Y.,Gwangju Institute of Science and Technology | Kwon I.K.,Kyung Hee University | And 3 more authors.
Advanced Materials | Year: 2014

By combining nanoimprint lithography technique and a two-step lift-off process, a Si nanotube array is fabricated and applied as a light absorber for n-Si/PEDOT:PSS hybrid solar cells. The light is effectively trapped within the nanotubes and the device reveals a Jsc of 29.9 mA·cm -2 and a power conversion efficiency of 10.03%, which is an enhancement of 13.4% compared to the cell having the best-known Si architecture of nanocones as a light absorber to date. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Kwon J.H.,Kyung Hee University
Information Display | Year: 2013

RGB color patterning is one of the key technologies for manufacturing large-sized AMOLED TVs. Two competing approaches are currently being used to realize RGB subpixels. One requires a more difficult manufacturing process but has better color purity; the other is easier to manufacture but requires optimization in algorithms to overcome some weaknesses. © SID 2013.

Kim Y.-R.,Kyung Hee University | Souza F.V.,Multimech Research and Development LLC | Teixeira J.E.S.L.,Federal University of Espirito Santo
Computational Mechanics | Year: 2013

This paper presents a quasi-static multiscale computational model with its verification and rational applications to mechanical behavior predictions of asphaltic roadways that are subject to viscoelastic deformation and fracture damage. The multiscale model is based on continuum thermo-mechanics and is implemented using a finite element formulation. Two length scales (global and local) are two-way coupled in the model framework by linking a homogenized global scale to a heterogeneous local scale representative volume element. With the unique multiscaling and the use of the finite element technique, it is possible to take into account the effect of material heterogeneity, viscoelasticity, and anisotropic damage accumulation in the small scale on the overall performance of larger scale structures. Along with the theoretical model formulation, two example problems are shown: one to verify the model and its computational benefits through comparisons with analytical solutions and single-scale simulation results, and the other to demonstrate the applicability of the approach to model general roadway structures where material viscoelasticity and cohesive zone fracture are involved. © 2012 Springer-Verlag.

Lee J.-Y.,Kyung Hee University | Raymond J.C.,Harvard - Smithsonian Center for Astrophysics
Astrophysical Journal | Year: 2012

The Ultraviolet Coronagraph Spectrometer (UVCS) on board the Solar and Heliospheric Observatory often observes low ionization state coronal mass ejection (CME) plasma at ultraviolet wavelengths. The CME plasmas are often detected in O VI (3 × 105K), C III (8 × 104K), Lyα, and Lyβ, with the low ionization plasma confined to bright filaments or blobs that appear in small segments of the UVCS slit. On the other hand, in situ observations by the Solar Wind Ion Composition Spectrometer on board Advanced Composition Explorer (ACE) have shown mostly high ionization state plasmas in the magnetic clouds in interplanetary coronal mass ejection (ICME) events, while low ionization states are rarely seen. In this analysis, we investigate whether the low ionization state CME plasmas observed by UVCS occupy small enough fractions of the CME to be consistent with the small fraction of ACE ICMEs that show low ionization plasma, or whether the CME plasma must be further ionized after passing the UVCS slit. To do this, we determine the covering factors of low ionization state plasma for 10CME events. We find that the low ionization state plasmas in CMEs observed by UVCS show average covering factors below 10%. This indicates that the lack of low ionization state ICME plasmas observed by the ACE results from a small probability that the spacecraft passes through a region of low ionization plasma. We also find that the low ionization state plasma covering factors in faster CMEs are smaller than in slower CMEs. © 2012. The American Astronomical Society. All rights reserved.

You Y.,Kyung Hee University
Current Opinion in Chemical Biology | Year: 2013

Recent advances in the development of the phosphorescent Ir(III) complexes have made it possible to implement the phosphorescence modality in bioimaging applications. A variety of phosphorescent Ir(III) complexes have been synthesized and assessed in the context of in vitro and in vivo imaging, especially in subcellular organelle staining and the sensing of biologically important analytes. The examples presented here demonstrate that Ir(III) complexes provide attractive alternatives to fluorescent organic compounds in the construction of biolabels and biosensors. The complexes are particularly advantageous with respect to fluorescent compounds in their compatibility with time-gated bioimaging techniques that completely eliminate background signals due to autofluorescence. © 2013 Elsevier Ltd.

Ryoo J.-H.,Kyung Hee University | Park S.K.,Sungkyunkwan University
Atherosclerosis | Year: 2013

Background and objective: There have been reports for the association between elevated serum apolipoprotein B (ApoB) and several cardiometabolic disorders. However, it remains unclear whether serum ApoB level predicts the development of metabolic syndrome (MetS). Accordingly, we carried out a prospective study to evaluate the longitudinal effects of baseline serum ApoB levels on the development of MetS. Patients and methods: A cohort of 25,193 healthy Korean men without MetS had been followed up prospectively. Baseline serum ApoB levels were categorized to following quintiles (quintile 1-5: <76.4, 76.4-88.4, 88.4-99.5, 99.5-113.0, ≥113.0). We evaluated the differences in the incidence of MetS according to quintiles of serum ApoB levels. Cox proportional hazards models were used to calculate the adjusted hazard ratios (HRs) for MetS. Results: During follow-up, 5407 (21.5%) cases developed MetS between 2006 and 2010. Incidence of MetS increased according to quintiles of serum ApoB levels [quintile 1-5: 9.1%, 16.4%, 22.1%, 27.3%, 36.4%, respectively (P for trend <0.001)]. Even after adjusting for various covariates including non-HDL-cholesterol, the hazard ratios (95% CI) for MetS increased in proportion to the quintiles of serum ApoB levels, compared to quintile 1 [quintile 2-5: 1.64 (1.43-1.89), 1.98 (1.71-2.31), 2.32 (1.96-2.75) and 2.92 (2.37-3.60), respectively (P for trend <0.001)]. These associations were apparent still in the clinically relevant subgroup analyses. Conclusions: Serum ApoB levels predict MetS, independent of baseline confounding variables including non-HDL-cholesterol. © 2012 Elsevier Ireland Ltd.

Chung E.T.,Chinese University of Hong Kong | Kim H.H.,Kyung Hee University
International Journal for Numerical Methods in Engineering | Year: 2014

Convergence theories and a deluxe dual and primal finite element tearing and interconnecting algorithm are developed for a hybrid staggered DG finite element approximation of H(curl) elliptic problems in two dimensions. In addition to the advantages of staggered DG methods, the basis functions of the new hybrid staggered DG method are all locally supported in the triangular elements, and a Lagrange multiplier approach is applied to enforce the global connections of these basis functions. The interface problem on the Lagrange multipliers is further reduced to the resulting problem on the subdomain interfaces, and a dual and primal finite element tearing and interconnecting algorithm with an enriched weight factor is then applied to the resulting problem. Our algorithm is shown to give a condition number bound of C(1+log(H/h))2, independent of the two parameters, where H/h is the number of triangles across each subdomain. Numerical results are included to confirm our theoretical bounds. © 2013 John Wiley & Sons, Ltd.

Bock G.-W.,Sungkyunkwan University | Lee J.,Kyung Hee University | Kuan H.-H.,Infocomm Development Authority of Singapore (iDA) | Kim J.-H.,Sungkyunkwan University
Decision Support Systems | Year: 2012

This research attempts to evaluate the effects of antecedents of online trust in the context of multi-channel retailers at different phases, taking into consideration the moderating effects of product types. The results reveal that multi-channel retailers' trust is transferred from the offline channel to the online channel. Secondly, the customers' initial interaction with the retailers ameliorates the effects of non-direct experience, such as Internet-based structural assurance and word-of-mouth. With increases in product uncertainty, the effects of word-of-mouth, offline trust, and efficacy of sanctions on online trust are greater for experience products than for search products. © 2012 Elsevier B.V. All rights reserved.

Park S.K.,Sungkyunkwan University | Ryoo J.-H.,Sungkyunkwan University | Ryoo J.-H.,Kyung Hee University | Kim M.-G.,Dongguk University | Shin J.-Y.,Seoul National University
Diabetes Care | Year: 2012

OBJECTIVE - Elevated serum ferritin has been known to be associated with the prevalence of metabolic syndrome (MetS). However, there was no research to examine whether serum ferritin levels have been actually associated with the prospective development of MetS. Accordingly, we carried out a prospective study to evaluate the longitudinal effects of baseline serumferritin levels on the development of MetS. RESEARCH DESIGN AND METHODS - A MetS-free cohort of 18,022 healthy Korean men, who had participated in a medical health checkup program in 2005, was followed until 2010. MetS was defined according to the joint interim statement of the International Diabetes Federation Task Force on Epidemiology and Prevention. Cox proportional hazards models were performed. RESULTS - During 45,919.3 person-years of follow-up, 2,127 incident cases of MetS developed between 2006 and 2010. After adjusting for multiple covariates, the hazard ratios (95%CI) for incident MetS comparing the second quintile to the fifth quintile of serumferritin levels versus the first quintile were 1.19 (0.98-1.45), 1.17 (0.96-1.43), 1.36 (1.12-1.65), and 1.66 (1.38-2.01), respectively (P for trend >0.001). These associations were apparent in the clinically relevant subgroup analyses. CONCLUSIONS - Elevated serum ferritin levels were independently associated with future development of MetS during the 5-year follow-up period. © 2012 by the American Diabetes Association.

Choi S.H.,Seoul National University | Byun K.M.,Kyung Hee University
Journal of the Optical Society of America A: Optics and Image Science, and Vision | Year: 2010

A surface plasmon resonance (SPR) imaging biosensor based on silver substrates was investigated to demonstrate that silver could be used as a substrate material for sensitive detection of biomolecular interactions, despite its poor chemical stability. The calculation results showed that oxidation of silver film may lead to a decrease in the sensitivity due to a variation in SPR characteristics such as a broader curve width and shallower minimum reflectance at resonance. The effect of a change in the refractive index of target analytes on the sensitivity was also explored. In particular, it is noteworthy that Ag/Au bimetallic substrates with a thin gold protection layer to prevent oxidation of a silver film can provide a significant amplification of SPR imaging signals in comparison with conventional gold substrates. © 2010 Optical Society of America.

Sheikh-Jabbaria M.M.,Institute for Research in Fundamental Sciences | Yavartanoob H.,Kyung Hee University
Journal of High Energy Physics | Year: 2011

Within class of generic black holes there are extremal black holes (with vanishing Hawking temperature T) and vanishing horizon area Ah, but with finite Ah/T ratio, the Extremal Vanishing Horizon (EVH) black holes. We study the near horizon limit of a four dimensional EVH black hole solution to a generic (gauged) Einstein-Maxwell dilaton theory and show that in the near horizon limit they develop a throat which is a pinching orbifold limit of AdS3. This is an extension of the well known result for extremal black holes the near horizon limit of which contains an AdS2 throat. We show that in the near EVH near horizon limit the pinching AdS3 factor turns to a pinching BTZ black hole and that this near horizon limit is indeed a decoupling limit. We argue that the pinching AdS3 or BTZ orbifold is resolved if the near horizon limit is accompanied by taking the 4d Newton constant G4 to zero such that the Bekenstein-Hawking entropy S = Ah/(4G4) remains finite. We propose that in this limit the near horizon EVH black hole is dual to a 2d CFT. We provide pieces of evidence in support of the EVH/CFT correspondence and comment on its connection to the Kerr/CFT proposal and speculations how the EVH/CFT may be used to study generic e.g. Schwarzchild-type black holes. © 2011 SISS.

Shin H.J.,Kyung Hee University
Journal of Physics A: Mathematical and Theoretical | Year: 2012

We solve the equations associated with the Lax pair of the nonlinear Schrödinger equation using a modified procedure of the squared wavefunction method. This solution, with the aid of the Darboux transformation, is used to study the soliton dynamics moving in phase-modulated lattices. It generalizes results from Sym's solution, and it can describe solitons on lattices with phase-modulated profiles as well as with flat-phase ones. We identify new effects of the phase-modulated lattices on soliton steering in comparison with the flat-phase lattices. © 2012 IOP Publishing Ltd.

Kim S.,Yonsei University | Hwang W.J.,Kyung Hee University
European Journal of Cardiovascular Nursing | Year: 2014

Background: Palliative care is an important element of holistic care but has received little attention in cardiac disease patients. The purpose of the paper is (a) to investigate nurses knowledge of palliative care, attitudes toward care of the dying, coping with death, and preparedness to practice palliative care for those with heart failure, and (b) to evaluate influencing factors on preparedness to practice on palliative care. Methods: A cross-sectional descriptive design employed a structured questionnaire that tested nurses knowledge, attitude, coping, and preparedness to practice on palliative care for patients with heart failure. Ninety nurses in two tertiary university hospitals in South Korea participated in the survey. Data were analyzed with descriptive statistics, correlation, and multiple regression. Results: Results showed low levels of knowledge reported (an average of 48.3% correct answers), attitude (134.8110.1), coping (117.224.3), and preparedness to practice (17.34.7) relating to palliative care. The extent of knowledge was related to both attitudes and coping. These attitudes and coping skills were related to preparedness to practice. The multiple regression analysis showed that preparedness to practice was explained by coping and attitude (R2 =0.46, F=6.1, p0.001). Conclusions: Palliative care training is urgently needed to improve knowledge, attitude, coping, and preparedness to practice. Guidance to assist healthcare professionals involved in palliative care for those with cardiac disease needs to be developed and provided. © The European Society of Cardiology 2013.

Magara T.,Kyung Hee University
Publications of the Astronomical Society of Japan | Year: 2013

We report on a new magnetohydrodynamic simulation for the sequence evolution of a magnetic field from emergence to eruption on the Sun. The magnetic field in the shape of a twisted flux tube emerging below the solar surface forms a pre-eruptive structure in the corona, which is composed of expanding envelop flux and a quasi-static inner core called flux rope; this inner core eventually seems to erupt. The evolution proceeds self-consistently; that is, any preexisting coronal magnetic field that causes additional side effects on the evolution of the emerging magnetic field is not assumed. This highlights a possible eruption mechanism inherent in the dynamic nature of the emerging magnetic field. The mechanism is characterized by two key quantities: the curvature (k) and the scale height (H) of the emerging magnetic field. © 2013. Astronomical Society of Japan.

Lee J.C.,Soonchunhyang University | Lee S.-H.,Kyung Hee University | Peters C.,University of Washington | Riew K.D.,University of Washington
Spine | Year: 2015

Study Design. A retrospective study. Objective. The purpose of this study was to determine, using survivorship analysis, the rate of adjacent segment pathology (ASP) development and to identify the risk factors for reoperation. Summary of Background Data. The study of Hilibrand defined "adjacent segment disease" as symptomatic radiculopathy or myelopathy due to an adjacent segment documented on 2 consecutive office visits. In addition to being somewhat subjective, their criterion is not as practical as identifying the rate of adjacent pathology by the need for reoperation. Methods. This was a retrospective analysis of 1038 consecutive patients who underwent primary anterior cervical spine arthrodesis for radiculopathy and/or myelopathy by 1 surgeon. Annual incidence and prevalence of ASP requiring surgery were calculated and survivorship was determined. We used the Cox regression for risk factor analysis. Results. Secondary surgery on adjacent segments occurred at a relatively constant rate of 2.4% per year (95% confidence interval, 1.9-3.0). The Kaplan-Meier analysis predicted that 22.2% of patients would need reoperation at adjacent segments by 10 years postoperatively. Factors increasing the risk were smoking, female sex, and the number of arthrodesis segments. One or 2-segment arthrodesis had an 1.8 times greater risk than arthrodesis involving 3 or more segments. Age, neurological diagnosis, diabetes, Klippel-Feil syndrome, and noncontiguous segmental-type ossification of posterior longitudinal ligament were not significant risks. Conclusion. Patients treated with 1- or 2-segment anterior cervical arthrodesis are more likely to develop ASP than those treated with arthrodesis involving 3 or more segments. Smokers and women had a higher ASP reoperation rate. Our series, the largest in the literature, predicts that 22.2% of patients will require reoperation for ASP within 10 years, substantially higher than the Hilibrand study. Copyright © 2015 Wolters Kluwer Health, Inc.

Bae C.-W.,Kyung Hee University
Journal of the Korean Medical Association | Year: 2016

Neonatology in pediatrics became a part of medical school curricula in Korea in 1954-1959. Specific treatments and procedures in the neonatal field were adopted around this period, for example, antibiotics, oxygen therapy, and the exchange transfusion procedure were established in 1950-1960. Usage of an infant incubator was implemented along with the establishment in 1960. The trend of separation between a premature infant care unit and newborn nursery room enabled the specialized treatment of high-risk infants in the 1970s. Assisted ventilation with continuous positive airway pressure and phototherapy was initiated in 1978. The recent concept of a neonatal intensive care unit was established in 1980, and it made so-called neonatal intensive care such as mechanical ventilation and intensive monitoring available. The Korean Society of Neonatology was founded in 1993. The usage of pulmonary surfactant in the 1990s, accelerated the improvement of respiratory distress syndrome survival, and it resulted in the nationwide opening of neonatal intensive care unit in hospitals. The high frequency ventilator and inhaled nitric oxide were introduced in the 2000s. The Korean Neonatal Network was commenced as a nationwide systemic database for very low birth weight infant registry in 2010. Accordingly, the history of Korean neonatology can be summarized as 50 years in total, and 35 years in a narrow sense. During this era, neonatal care in Korea has improved remarkably and has achieved a great survival rate for high-risk neonates, preterm infants, and micro-premies. In this review, we intend to provide an overview of the history, efforts, and outcomes of Korean neonatology activity that have led to these achievements. © Korean Medical Association.

Yavartanoo H.,Kyung Hee University
European Physical Journal C | Year: 2012

We analyze the effect of higher derivative corrections to the near horizon geometry of the extremal vanishing horizon (EVH) black hole solutions in four dimensions. We restrict ourselves to a Gauss-Bonnet correction with a dilation dependent coupling in an Einstein-Maxwell-dilaton theory. This action may represent the effective action as it arises in tree level heterotic string theory compactified to four dimensions or the K3 compactification of type II string theory. We show that EVH black holes, in this theory, develop an AdS 3 throat in their near horizon geometry. © 2012 Springer-Verlag / Società Italiana di Fisica.

Ashoorioon A.,Lancaster University | Dimopoulos K.,Lancaster University | Sheikh-Jabbari M.M.,Institute for Research in Fundamental Sciences | Sheikh-Jabbari M.M.,Kyung Hee University | And 2 more authors.
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

The BICEP2 experiment has announced a signal for primordial gravity waves with tensor-to-scalar ratio r=0.2-0.05+0.07 [1]. There are two ways to reconcile this result with the latest Planck experiment [2]. One is by assuming that there is a considerable tilt of r, Tr, with a positive sign, Tr=dlnr/dlnk≳0.57-0.27+0.29 corresponding to a blue tilt for the tensor modes of order nT≃0.53-0.27+0.29, assuming the Planck experiment best-fit value for tilt of scalar power spectrum n S. The other possibility is to assume that there is a negative running in the scalar spectral index, dn S/dln k ≃ - 0.02 which pushes up the upper bound on r from 0.11 up to 0.26 in the Planck analysis assuming the existence of a tensor spectrum. Simple slow-roll models fail to provide such large values for Tr or negative runnings in n S [1]. In this note we show that a non-Bunch-Davies initial state for perturbations can provide a match between large field chaotic models (like m2φ2) with the latest Planck result [3] and BICEP2 results by accommodating either the blue tilt of r or the negative large running of n S. © 2014 The Authors.

Moon S.W.,Kyung Hee University
Korean journal of ophthalmology : KJO | Year: 2011

A 60-year-old man with bilateral corneal opacity underwent cataract extraction surgery involving the use of a limbal relaxing incision in his left eye. He had lower lid ectropion and lagophthalmos in both eyes. Eleven days after the surgery, a slit-lamp examination revealed a neurotrophic corneal ulcer with a punch-out epithelial defect and rolled edges at the center of the pre-existing corneal opacity. The patient was treated with sodium hyaluronate, autologous serum, and oral doxycycline. Six weeks after the surgery an improvement in corneal sensation was observed and the neurotrophic corneal ulcer subsequently healed over the course of one year. In this report, we present a case of neurotrophic keratitis that occurred after performing cataract surgery concurrent with a limbal relaxing incision. As such, we suggest that limbal relaxing incisions should be performed cautiously in patients with causative risk factors for corneal hypesthesia.

Lee E.-J.,Howard Hughes Medical Institute | Lee E.-J.,Yale University | Lee E.-J.,Yale Microbial Diversity Institute | Lee E.-J.,Kyung Hee University | And 5 more authors.
Cell | Year: 2013

Several intracellular pathogens, including Salmonella enterica and Mycobacterium tuberculosis, require the virulence protein MgtC to survive within macrophages and to cause a lethal infection in mice. We now report that, unlike secreted virulence factors that target the host vacuolar ATPase to withstand phagosomal acidity, the MgtC protein acts on Salmonella's own F 1Fo ATP synthase. This complex couples proton translocation to ATP synthesis/hydrolysis and is required for virulence. We establish that MgtC interacts with the a subunit of the F1F o ATP synthase, hindering ATP-driven proton translocation and NADH-driven ATP synthesis in inverted vesicles. An mgtC null mutant displays heightened ATP levels and an acidic cytoplasm, whereas mgtC overexpression decreases ATP levels. A single amino acid substitution in MgtC that prevents binding to the F1Fo ATP synthase abolishes control of ATP levels and attenuates pathogenicity. MgtC provides a singular example of a virulence protein that promotes pathogenicity by interfering with another virulence protein. © 2013 Elsevier Inc.

Yavartanoo H.,Kyung Hee University
European Physical Journal C | Year: 2012

We analyze the possible dynamical emergence of IR conformal field theory describing the low-energy excitations of near-extremal black holes in five-dimensional compactification of heterotic strings. We find that, by tuning the mass and charges in such a way that the extremal black holes have a classically vanishing horizon area, the near horizon develops an AdS 3 throat and when we combine the low-energy limit with vanishing Newton coupling constant, the system has a dual conformal field theory description. We compare our results with c-extremization and the Kerr/CFT predictions. © 2012 Springer-Verlag Berlin Heidelberg and Società Italiana di Fisica.

Yavartanoo H.,Kyung Hee University
European Physical Journal C | Year: 2012

We study the near-horizon geometry of four-dimensional charged static black holes in heterotic string theory and analyze the possible dynamical emergence of dual IR conformal field theory. We find that when we turn on mass and charges in such a way that extremal black holes have classically vanishing horizon area, the near horizon develops an AdS3 throat and when we combine the low energy limit with vanishing Newton coupling constant, the system has a dual conformal field theory description. We compare our results with c-extremization and the Kerr/CFT predictions. © 2012 Springer-Verlag Berlin Heidelberg and Società Italiana di Fisica.

Nam H.,Kyung Hee University
IEEE Transactions on Consumer Electronics | Year: 2010

In LCD applications, various low power techniques, such as low voltage driving LEDs, high efficiency DC-DC converter circuitries, active backlight control schemes and the likes, have been applied to a backlight, which occupies the huge portion of total power consumption. Especially, it is a well-known fact that active dimming methods have accomplished considerable power reduction by as much as 20% up to 50% compared to the constant backlight method. However, the former technique may involve several artifacts such as color distortion, clipping, and so on. In this paper, color distortion in an active dimming LCD system caused by the mismatch between gamma values of pixel compensation algorithm and RGB sub-pixels, is analyzed and lowered by the proposed color compensation algorithm. This color compensation algorithm achieves the dramatic reduction on the color distortion without any loss of power saving performances. The maximum color difference ΔEabmax has been measured for each test image with the previous pixel compensation approaches (method-1 and method-2), and the average value of ΔEabmax has been obtained over 24 KODAK images. The resultant average value of a color compensated active dimming algorithm has been reduced to 0.413 and 0.478, compared to 24.595 and 9.527 of the conventional active dimming algorithms for method-1 and method-2, respectively. © 2006 IEEE.

Yun G.Y.,Kyung Hee University | Steemers K.,University of Cambridge
Solar Energy | Year: 2010

This paper investigates occupant behaviour of window-use in night-time naturally ventilated offices on the basis of a pilot field study, conducted during the summers of 2006 and 2007 in Cambridge, UK, and then demonstrates the effects of employing night-time ventilation on indoor thermal conditions using predictive models of occupant window-use. A longitudinal field study shows that occupants make good use of night-time natural ventilation strategies when provided with openings that allow secure ventilation, and that there is a noticeable time of day effect in window-use patterns (i.e. increased probability of action on arrival and departure). We develop logistic models of window-use for night-time naturally ventilated offices, which are subsequently applied to a behaviour algorithm, including Markov chains and Monte Carlo methods. The simulations using the behaviour algorithm demonstrate a good agreement with the observational data of window-use, and reveal how building design and occupant behaviour collectively affect the thermal performance of offices. They illustrate that the provision of secure ventilation leads to more frequent use of the window, and thus contributes significantly to the achievement of a comfortable indoor environment during the daytime occupied period. For example, the maximum temperature for a night-time ventilated office is found to be 3 °C below the predicted value for a daytime-only ventilated office. © 2010 Elsevier Ltd. All rights reserved.

Lee J.-H.,LG Corp | Rhee K.Y.,Kyung Hee University | Park S.J.,Inha University
Composites Part A: Applied Science and Manufacturing | Year: 2011

Carbon/CNT/epoxy three-phase composites were fabricated by incorporating woven carbon fibers into epoxy mixed with multi-walled carbon nanotubes (MWCNTs). Three carbon/CNT/epoxy composites were fabricated containing unmodified, acid-modified, and silane-modified CNTs at 1 wt.% to investigate the effects of the silane-modified CNTs on the mechanical, thermal, and electrical properties of the three-phase composites. The results showed that the elastic modulus and tensile strength of the carbon/CNT/epoxy three-phase composites were improved by silane modification of the CNTs. Specifically, the elastic modulus of the silane-modified carbon/CNT/epoxy composite was approximately 13% and 18% higher than that of the acid-modified and unmodified composites, respectively. The tensile strength of the silane-modified carbon/CNT/epoxy composite was 8.4% and 15.8% higher than that of the acid-modified and unmodified composites, respectively. In addition, the thermal properties and electrical conductivity of the carbon/CNT/epoxy composites were improved due to silane modification of the CNTs. © 2011 Elsevier Ltd. All rights reserved.

Kim J.A.,Seoul National University | Lee W.G.,Kyung Hee University
Nanoscale | Year: 2011

In this study, we present a role for weakly polarized nanoparticles as engineered gene transporters that can enhance electromediated gene delivery. To validate this proof-of-concept, fluorescent poly(ethylene glycol) (PEG)-coated silica nanoparticles (SiNPs) with opposite polarities, SiNPs(RITC)-PEG/PTMA(+) and SiNPs(RITC)-PEG/PMP(-), are used. To investigate the electroporative uptake direction of the nanoparticles-gene complex, we employ microscale electroporation to generate more symmetric and uniform electric fields. The effect of the polarity of the nanoparticles on EGFP gene transfection efficiency in HeLa cells is measured by flow cytometry analysis. The results show that, compared to cationic nanoparticles, anionic nanoparticles have potential as electromediated gene transporters at a low gene concentration. Furthermore, we believe that this finding can be useful for developing a platform that enables electroporation-based gene/drug delivery associated with functional nanoparticles. © 2011 The Royal Society of Chemistry.© 2011 The Royal Society of Chemistry.

Wang X.,University of New South Wales | Wang X.,Kyung Hee University | Dunston P.S.,Purdue University
IEEE Transactions on Systems, Man and Cybernetics Part C: Applications and Reviews | Year: 2011

This paper presents two mixed-reality (MR) environments that provide alternative mediums that allow groups of people to share the same work and communication space in face-to-face and remote manners. Two experiments were executed to test the capabilities of the two MR systems in realistic environment and collaborative tasks against prevalent methods. Results indicated that the two MR systems significantly reduced the performance time for the collaborative design error detection task. Results also indicated less mental effort for the MR systems, suggesting that some of the mental interpretation for the error detection task is offloaded to the MR systems. © 2010 IEEE.

Pode R.,Kyung Hee University
Renewable and Sustainable Energy Reviews | Year: 2016

Rice husk (RH), an agricultural waste, is abundantly available in rice producing countries like China, India, Bangladesh, Brazil, US, Cambodia, Vietnam, Myanmar, and South East Asia. Despite the massive amount of annual production worldwide, so far RHs have been recycled only for low-value applications. In recent years, many rice mills in rice producing countries have started using RH for the energy production for mill operations as well as household lighting in rural regions. Burning of RHs produces the rice husk ash (RHA). The disposal in landfills or open fields can be problematic and may cause a serious environmental and human health related problems due to the low bulk density of RHA. Several ways are being thought of for disposing RHA by making its commercial use. The amorphous silica forms the main component (83-90%) of RHA. The amorphous silica rich RHA has wide range of applications. High-value applications and current research investigations such as the use of RHA in manufacturing of silica gels, silicon chip, synthesis of activated carbon and silica, production of light weight construction materials and insulation, catalysts, zeolites, ingredients for lithium ion batteries, graphene, energy storage/capacitor, carbon capture, and in drug delivery vehicles are presented. Use of RHA in potential future applications is also discussed. It is suggested that the amorphous silica rich RHA could become a potential resource of low cost precursor for the production of value-added silica based materials for practical applications. © 2015 Elsevier Ltd. All rights reserved.

Lee K.C.,Sungkyunkwan University | Chung N.,Kyung Hee University | Lee S.,Sejong University
Information and Management | Year: 2011

Due to competition, most firms try to retain and lock in customers; this is likely to ensure a greater market profit than that gained by acquiring new customers. While many studies have investigated customer satisfaction and retention in online and offline firms, scant research exists on customer satisfaction and customer retention in the context of brick-and-click firms: i.e., those that conduct business both online and in stores. Such firms encourage trust transfer among their customers. However, most studies have failed to consider the role of personal schema in trust transfer. Based on social exchange, investment, and information integration theories, we analyzed the impact of trust transfer, switching costs, and personal schema on customer satisfaction and repurchase intentions in the context of an offline bookstore that has now launched an online business. Our results indicated that trust transfer and switching costs had a small effect on customer satisfaction and repurchase intentions. Personal schema, however, affected both customer satisfaction and repurchase intention. © 2011 Elsevier B.V.

Lee M.,Kyung Hee University | Lim J.S.,Institute Of Fisica Interdisciplinar I Of Sistemes Complexos Ifisc Csic Uib | Lopez R.,Institute Of Fisica Interdisciplinar I Of Sistemes Complexos Ifisc Csic Uib | Lopez R.,University of the Balearic Islands
Physical Review B - Condensed Matter and Materials Physics | Year: 2013

We investigate the dynamical and transport features of a Kondo dot side coupled to a topological superconductor (TS). The Majorana fermion states (MFSs) formed at the ends of the TS are found to be able to alter the Kondo physics profoundly: For an infinitely long wire where the MFSs do not overlap (εm=0) a finite dot-MFS coupling (Γm) reduces the unitary-limit value of the linear conductance by exactly a factor 3/4 in the weak-coupling regime (ΓmTK), on the other hand, the spin-split Kondo resonance takes place due to the MFS-induced Zeeman splitting, which is a genuine many-body effect of the strong Coulomb interaction and the topological superconductivity. We find that the original Kondo resonance is fully restored once the MFSs are strongly hybridized (εm>Γ m). This unusual interaction between the Kondo effect and the MFS can thus serve to detect the Majorana fermions unambiguously and quantify the degree of overlap between the MFSs in the TS. © 2013 American Physical Society.

Regula B.,University of Nottingham | Di Martino S.,University of Nottingham | Di Martino S.,University of Bari | Lee S.,University of Nottingham | And 2 more authors.
Physical Review Letters | Year: 2014

We investigate the distribution of bipartite and multipartite entanglement in multiqubit states. In particular, we define a set of monogamy inequalities sharpening the conventional Coffman-Kundu-Wootters constraints, and we provide analytical proofs of their validity for relevant classes of states. We present extensive numerical evidence validating the conjectured strong monogamy inequalities for arbitrary pure states of four qubits. © 2014 American Physical Society.

Hong M.,Kyung Hee University
BMC medical education | Year: 2012

This study aims to determine the correlation between medical education systems, medical college (MC) and medical school (MS), and empathy by investigating the changes in empathy among students with each additional year of medical education. The subjects were MC and MS students who had participated in the same study the previous year. All participants completed the same self-report instruments: a questionnaire on sociodemographic characteristics, and the Korean edition of the Student Version of the Jefferson Scale of Empathy (JSE-S-K), Among 334 students, the final analysis was conducted on the data provided by 113 MC and 120 MS students, excluding 101 with incomplete data. The age and sex did not affect the changes in empathy. Though the JSE-S-K score of MS was significantly higher than that of MC in initial investigation, this study found no difference of empathy between MC and MS. Empathy increased significantly after one year of medical education. The difference between two education systems, MC and MS, did not affect the changes in empathy.

Cho N.S.,Kyung Hee University
The American journal of sports medicine | Year: 2011

Suture bridge repair has been recognized to have superior biomechanical characteristics, as shown in previous biomechanical studies. However, it is not clear whether the tendon heals better in vivo after suture bridge repair. To evaluate the clinical results and repair integrity after arthroscopic rotator cuff repair using a suture bridge technique for patients with rotator cuff tears. Case series; Level of evidence, 4. One hundred twenty-three shoulders (120 patients) that underwent arthroscopic suture bridge repair for full-thickness rotator cuff tear were enrolled for this study. The mean duration of follow-up was 25.2 months (range, 16-34 months). The postoperative repair integrity was analyzed with use of magnetic resonance imaging (MRI) in 87 shoulders. According to the retear patterns on postoperative MRI, the cases were divided into type 1 (failure at the original repair site) or 2 (failure around the medial row). At the last follow-up, the University of California at Los Angeles (UCLA) score improved from the preoperative mean of 13.2 points to 29.7 points (P < .001). The rotator cuff was completely healed in 58 (66.7%) of the 87 shoulders, and there was a recurrent tear in 29 shoulders (33.3%). The incidence of retear tended to increase with age older than 60 years at the time of surgery (P = .002). When there was a larger intraoperative tear, the rate of retear was also higher (P = .002). When the severity of preoperative fatty degeneration of the cuff muscles was higher, there was a greater chance of a recurrent tear (P < .001). The retear patterns on postoperative MRI in 29 shoulders with recurrent failures were classified as type 1 in 12 shoulders (41.4%) and type 2 in 17 shoulders (58.6%). The preoperative cuff tear size did not have an influence on retear patterns (P = .236), but the percentage of type 1 retear increased with the severity of fatty degeneration or muscle atrophy (P = .041, .023). Arthroscopic suture bridge repair of full-thickness rotator cuff tears led to a relatively high rate of recurrent defects. However, the mean 25-month follow-up demonstrated excellent pain relief and improvement in the ability to perform the activities of daily living, despite the structural failures. The factors affecting tendon healing were the patient's age, the size and extent of the tear, and the presence of fatty degeneration in the rotator cuff muscle. The retear in cases with a suture bridge technique tended to be more frequently at the musculotendinous junction.

Rhyee J.-S.,Kyung Hee University | Ahn K.,Samsung | Lee K.H.,Samsung | Ji H.S.,Pohang University of Science and Technology | Shim J.-H.,Pohang University of Science and Technology
Advanced Materials | Year: 2011

The state-of-the-art record of thermoelectric figure-of-merit (ZT) of 1.53 at 425 °C is achieved by chlorine doping in In4Se 3-xCl0.03 bulk crystalline materials as used for n-type thermoelectric energy harvesting. The low-dimensional property imparted by chlorine doping significantly increases the electrical conductivity and reduces the thermal conductivity resulting in a high power factor over a wide temperature range. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gaire B.P.,Kyung Hee University | Subedi L.,Pokhara University
Journal of Chinese Integrative Medicine | Year: 2013

Datura stramonium L., a wild-growing plant of the Solanaceae family, is widely distributed and easily accessible. It contains a variety of toxic tropane alkaloids such as atropine, hyoscamine, and scopolamine. In Eastern medicine, especially in Ayurvedic medicine, D. stramonium has been used for curing various human ailments, including ulcers, wounds, inflammation, rheumatism and gout, sciatica, bruises and swellings, fever, asthma and bronchitis, and toothache. A few previous studies have reported on the pharmacological effects of D. stramonium; however, complete information regarding the pharmacology, toxicity, ethnobotany and phytochemistry remains unclear. Ethnomedicinally, the frequent recreational abuse of D. stramonium has resulted in toxic syndromes. D. stramonium, in the form of paste or solution to relieve the local pain, may not have a deleterious effect; however, oral and systemic administration may lead to severe anticholinergic symptoms. For this reason, it is very important for individuals, mainly young people, to be aware of the toxic nature and potential risks associated with the use of this plant. This comprehensive review of D. stramonium includes information on botany, phytochemistry, pharmacology, toxicology and ethnomedicinal uses. © 2013 Bhakta Prasad Gaire et al.

Choi B.G.,KAIST | Park H.S.,Kyung Hee University
Journal of Physical Chemistry C | Year: 2012

The micro- and macroscopic structures of functional films strongly influence the critical properties, such as superhydrophobicity, which exhibits super water repellency with a water contact angle (CA) larger than 150° for self-cleaning and antimicrobial surfaces. However, it is difficult to achieve the structural hierarchy of two-dimensional graphene for superhydrophobicity. Herein, we report the fabrication of superhydrophobic graphene/Nafion nanohybrid films by controlling the structures with respect to the chemical composition from an interpenetrating networked and compactly interlocked structure (surface area of 9.56 m 2 g -1) to the hierarchical petal-like, porous structure (surface area of 413.46 m 2 g -1). The superhydrophobicity of hybrid thin films with a CA of ∼161° was derived from the petal-like structure with hierarchical roughness, where microscale roughness was produced in the lateral direction of hybrid sheets while nanoscopic roughness was created on the edges of hybrid sheets. Furthermore, the wettability and optical and electrical properties of hybrid thin films can be controlled by manipulating the micro- and macroscale structures through the composition-dependent structural changes. © 2012 American Chemical Society.

Yoon H.S.,Kyung Hee University
Journal of the Korean Medical Association | Year: 2011

Iron deficiency anemia (IDA) frequently occurs in infants and adolescents. IDA is the result of an interplay between increased host requirements, limited external supply, and increased blood loss. In outpatient clinics, we often see children with iron deficiency anemia. Most cases in children are caused by incomplete nutrient supplements and growth spurts. However, we can occasionally see patients with poor response despite iron supplementation. Failure of iron therapy occurs when a child does not receive the prescribed medication, when iron is given in a form that is poorly absorbed, or when there is a continuing unrecognized blood loss such as intestinal or pulmonary loss, or loss with menstrual periods. In addition, the therapeutic failure of iron medication may indicate that the original diagnosis of nutritional iron deficiency was incorrect. In this situation, we have to evaluate other etiologies of anemia. Recently, many cases relating H.pylori infection to iron deficiency anemia have been described in the literature and H.pylori infection has emerged as a cause of refractory iron deficiency anemia that is unresponsive to oral iron therapy. Also, iron deficiency anemia induced by athletics in adolescent females has been reported several times. In this article, the author reviews various etiologies of childhood iron deficiency anemia. The most important consideration in treatment of iron deficiency anemia is disclosure of the underlying cause and its recovery. Dietary habits should also be corrected. To supplement iron, 6 mg/kg of oral iron supplements (elemental iron) is recommended in ferrous salt form. If oral administration is not feasible, intravenous supplementation is recommended using forms such as iron dextran, iron gluconate, or iron sucrose. © Korean Medical Association.

Jung J.,Kyung Hee University
The International journal of oral & maxillofacial implants | Year: 2011

This study was designed to investigate the prevalence and course of the vascular canals in the maxillary sinus walls and to measure the distance between the sinus floor, the edentulous alveolar crest, and the vascular canal using cone beam computed tomography (CBCT). The maxillary sinus CBCT scans of 250 patients scheduled for implant surgery were examined. The vertical and mediolateral positions of the vascular canals or notches were investigated on the CBCT images. The location of each tooth was confirmed using a diagnostic template for implant placement. Statistical analyses were performed to verify whether the mean artery position was significantly different according to each tooth location, gender, and age. A maxillary arterial endosseous anastomosis was observed in 52.8% of patients. The mean perpendicular distance from the sinus floor to the vascular canal was shortest in the first molar region (7.58 ± 3.19 mm) and longest in the first premolar region (9.2 ± 3.22 mm). The mean distance from the alveolar crest to the vascular canal was shortest in the first molar region (14.79 ± 4.04 mm) and longest in the first premolar region (18.92 ± 4.86 mm). These distances were significantly different according to tooth position. The mean distances from the alveolar crest and the sinus floor to the vascular canal did not decrease with age. The mediolateral position of the canals was also significantly different depending on tooth position. With this information about the branch of the posterior superior alveolar artery from CBCT, unnecessary bleeding during implant placement should be more easily preventable. The use of CBCT is recommended as a routine procedure prior to sinus floor elevation.

Lee J.-H.,University of California at Los Angeles | Lee J.-H.,Kyung Hee University | Ang J.K.,University of California at Los Angeles | Xiao X.,University of California at Los Angeles
RNA | Year: 2013

RNA-sequencing (RNA-Seq) technologies hold enormous promise for novel discoveries in genomics and transcriptomics. In the past year, a surge of reports has analyzed RNA-Seq data to gain a global view of the RNA editome. Opposing results have been presented, giving rise to extensive debate surrounding one of the first such studies in which a daunting list of all 12 types of RNA-DNA differences (RDDs) were identified. Although a consensus is forming that some of the initial "paradigm-shifting" results of this study may be questionable, recent reports on this topic differed in terms of the number and relative abundance of each type of RDD. Many outstanding issues exist, most importantly, the choice of bioinformatic approaches. Here we discuss the critical data analysis and experimental design issues of such studies to enable improved systematic investigation of the largely unexplored frontier of single-nucleotide variants in RNA. Published by Cold Spring Harbor Laboratory Press. Copyright © 2013 RNA Society.

Kim S.-K.,Kyung Hee University | Park H.-G.,Korea University
Optics Express | Year: 2013

We propose a dielectric Bragg mirror that utilizes coherent coupling with multiple quantum wells (MQWs) to significantly enhance light extraction from GaN light-emitting diode (LED). Full vectorial electromagnetic simulation showed that, under constructive interference conditions, the Bragg mirror consisting of two dielectric (SiO2/TiO2) stacks and a silver layer led to >30% enhancement in light extraction, as compared to a single silver mirror. Such significant enhancement by a pre-designed Bragg/metal mirror was ascribed to the vertically oriented radiation pattern and reduced plasmonic metal loss. In addition, the gap distance between the MQWs and a Bragg mirror at which the constructive interference takes place could be controlled by modulating the thickness of the first lowrefractive- index layer. Moreover, a two-dimensional periodic pattern was incorporated into an upper GaN layer with the designed Bragg mirror and it was shown that a lattice constant of ~800 nm was optimal for light extraction. We believe that tailoring the radiation profile of light emitters by coherent coupling with designed high-reflectivity mirrors will be a promising route to overcome the efficiency limit of current semiconductor LED devices. © 2013 Optical Society of America.

Yoo E.-H.,Kyung Hee University | Kim D.,Sungkyunkwan University
International Urogynecology Journal and Pelvic Floor Dysfunction | Year: 2013

Introduction and hypothesis: The study sought to identify the risk factors of postoperative use of antimuscarinics after transobturator surgery in women with mixed urinary incontinence (MUI) displaying both urodynamic stress urinary incontinence (SUI) and involuntary detrusor contraction (IDC) with leakage in urodynamic study. Methods: The clinical data of 103 patients with MUI who underwent transobturator tape (TOT) sling surgery were retrospectively reviewed. The patients were followed at least a year. To determine risk factors for postoperative use of antimuscarinics, variables of only those with P values < 0.05 on univariate analysis were included in the multivariate logistic regression analysis with forward stepwise building. Results: Eight-four (81.6 %) of 103 patients were included in this study. The cure rate of urge urinary incontinence (UUI) was 69.0 % (58/84). Antimuscarinics were prescribed postoperatively in 22 (26.2 %) of 84 patients. Variables affecting postoperative use of antimuscarinics were age, parity, episode of any UUI, preoperative use of antimuscarinics, predominant urgency incontinence type, detrusor pressure at maximum flow, and Urogenital Distress Inventory 6. Increasing age and preoperative use of antimuscarinics increased the odds of postoperative use of antimuscarinics following TOT surgery. Conclusion: Patients who were older and had taken antimuscarinics preoperatively were significantly associated with postoperative use of antimuscarinics. © 2012 The International Urogynecological Association.

Kim S.J.,Kyung Hee University | Courtin R.,University of Paris Descartes
Astronomy and Astrophysics | Year: 2013

We retrieved optical-depth spectra of the Titanian haze in the range 1-5 μm from solar occultation data obtained by the Cassini/Visual Infrared Mapping Spectrometer (VIMS) at altitudes of 59-502 km. Only limited wavelength intervals within this spectral range have been analyzed before. The haze spectra we retrieved are mostly similar to those of alkane particles (or powders), with three major absorption peaks typical of alkane powders at 2.3, 3.4, and 4.3 μm. This result suggests that at least in the ∼60-500 km altitude range, the Titanian haze is mostly composed of alkane particles, possibly with some trace impurities. The absence of the 3.0 and 4.6 μm features excludes the molecules containing NH and CN bonds that are typical of laboratory-made tholins reported in the literature. The alkane-like spectral characteristics of the haze we observed at ∼60-500 km differ from previous results obtained at different or overlapping altitudes: a) the presence of aromatic compounds derived from solar-pumped emissions observed at high altitude (600-1250 km) by Cassini/VIMS near 3.3 μm; and b) the detection of HCN and NH3 in the cores of haze particles collected at low altitude (20-130 km) by the Huygens/Aerosol Collector and Pyrolyser (ACP). We suggest that these different characteristics arise from different structural layers formed by coagulation/coalescence during particle sedimentation. © 2013 ESO.

The aim of this study was to analyze and compare the level and distribution of peri-implant bone stresses associated with mandibular two-implant overdentures with different implant positions. Mathematical models of mandibles and overdentures were designed using finite element analysis software. Two intraosseous implants and ball attachment systems were placed in the interforaminal region. The overdenture, which was supported by the two implants, was designed to withstand bilateral and unilateral vertical masticatory loads (total 100 N). In all, eight types of models, which differed according to assigned implant positions, height of attachments, and angulation, were tested: MI (model with implants positioned in the lateral incisor sites), MC (implants in canine sites), MP (implants in premolar sites), MI-Hi (greater height of attachments), MC-M (canine implants placed with mesial inclination), MC-D (canine implants placed with distal inclination), MC-B (canine implants placed with buccal inclination), and MC-L (canine implants placed with lingual inclination). Peri-implant bone stress levels associated with overdentures retained by lateral incisor implants resulted in the lowest stress levels and the highest efficiency in distributing peri-implant stress. MI-Hi showed increased stress levels and decreased efficiency in stress distribution. As the implants were inclined, stress levels increased and the efficiency of stress distribution decreased. Among the inclined models, MC-B showed the lowest stress level and best efficiency in stress distribution. The lowest stress and the best stability of implants in mandibular two-implant overdentures were obtained when implants were inserted in lateral incisor areas with shorter attachments and were placed parallel to the long axes of the teeth.

Wee K.-R.,Sejong University | Cho Y.-J.,Sejong University | Song J.K.,Kyung Hee University | Kang S.O.,Sejong University
Angewandte Chemie - International Edition | Year: 2013

Naphthyl-substituted ortho-carboranes, which were prepared following the reaction between acetylene and decarborane, showed unique multiple photoluminescence behavior associated with intramolecular charge transfer (see picture). On the basis of theoretical calculations, the photoluminescence is shown to originate from the overlap between the naphthyl π orbital and the carboranyl σ orbital. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

OBJECTIVE: The purpose of this study was to classify the types of medial synovial fold of the posterior cruciate ligament (PCL) on magnetic resonance imaging (MRI) and to identify the relationships between fold type and impingement of the PCL on arthroscopy. SUBJECTS AND METHODS: Ninety-nine patients who underwent knee MRI and arthroscopy were included. All MRIs were retrospectively and independently assessed by 2 radiologists. Medial synovial folds of the PCL on MRI were categorized into 3 types. Type A showed no medial synovial fold. Type B showed a small synovial protrusion that did not extend beyond an imaginary line drawn from the medial tibial spine to the lateral aspect of the medial femoral condyle. Type C had a long enough fold to extend beyond the imaginary line. The presence of a tear in the anterior cruciate ligament, PCL, or menisci and impingement of the PCL were obtained from arthroscopic records. RESULTS: Intraobserver agreement in the classification of medial synovial folds was nearly perfect (κ = 0.850). Interobserver agreement was substantial (κ = 0.759). Of 99 cases, 34 were type A, 41 were type B, and 24 were type C folds on MRI. Thirty-nine impingements of the PCL (39.4%) were identified on arthroscopy. Multivariable analysis revealed that type C folds were 40.60 times more likely to have impingement than type A folds (odds ratio, 40.60; 95% confidence interval, 8.73–188.93; P < 0.001). CONCLUSIONS: Of the 3 types of medial synovial folds, type C was significantly associated with impingement of the PCL on arthroscopy. Therefore, type C folds may be a cause of internal derangement of the knee. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.

OBJECTIVES: This study sought to explore the association between the Framingham Risk Score (FRS) and coronary plaque characteristics assessed by optical coherence tomography (OCT) imaging. BACKGROUND: Clinical prediction models are useful for identifying high-risk patients. However, coronary events often occur in individuals estimated to be at low risk. METHODS: A total of 254 patients with coronary artery disease who underwent three-vessel OCT were divided into tertiles according to FRS. Nonculprit plaque characteristics were compared among the three groups. RESULTS: A total of 663 plaques were analyzed. FRS was significantly associated with calcification [37% (low FRS) vs. 46% (intermediate FRS) vs. 70% (high FRS); P<0.001] and neovascularization [39% (low FRS) vs. 41% (intermediate FRS) vs. 56% (high FRS); P<0.001], but not with lipid-rich plaques or thin-cap fibroatheroma (TCFA). On multivariate analysis, FRS was an independent predictor of the presence of both calcification and neovascularization. There were no deaths, two acute myocardial infarctions, and 15 nontarget lesion revascularizations at the 1-year follow-up. The event rate increased progressively across FRS tertiles [2.4% (low FRS) vs. 7.1% (intermediate FRS) vs. 8.6% (high FRS); P=0.186]. The c-statistic for FRS to predict future clinical events was 0.628 (95% confidence interval, 0.500−0.757). The addition of both calcification and TCFA to FRS provided incremental prognostic value [c-statistics: 0.761 (95% confidence interval, 0.631−0.890)]. CONCLUSION: The present study showed significant associations between FRS and the presence of coronary calcification and neovascularization in nonculprit plaques. The combination of FRS and OCT-detected calcifications and TCFA provides improved prognostic ability in identifying patients with known coronary artery disease who are at risk of recurrent events. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.

Kim H.J.,Kyung Hee University
Journal of cosmetic science | Year: 2013

Effective and safe antimelanogenic agents derived from natural products get interest continuously for both medical and cosmetic purposes. Melanin synthesis is regulated by melanogenic enzymes such as tyrosinase, tyrosinase-related protein 1 (TRP-1), and tyrosinase-related protein 2 (TRP-2) in mammals. Gastrodia elata (GE) has been shown to have multiple therapeutic actions related to antioxidation in many diseases. In this study, we investigate whether water extraction of GE has inhibitory effects on melanogenesis in vitro and on the expression of mRNA and protein of tyrosinase, TRP-1, and TRP-2 in HM3KO melanoma cells. To examine the inhibitory effect of GE on melanogenesis, mushroom tyrosinase inhibition assay; reverse transcription polymerase chain reaction; and western blotting of tyrosinase, TRP-1, and TRP-2 were performed using HM3KO melanoma cells. In this study, the GE extract was found to significantly inhibit mushroom tyrosinase activity (69.3 ± 7.2% of the control, p < 0.05), and the expression of mRNA and protein of tyrosinase, TRP-1, and TRP-2 was reduced significantly. These results suggest that the antimelanogenic effect of GE extract is mainly due to the decreased expression of mRNA and protein of tyrosinase, TRP-1, and TRP-2 in the process of melanin synthesis.

Hong J.,Seoul National University | Min S.-W.,Kyung Hee University | Lee B.,Seoul National University
Applied Optics | Year: 2012

Novel integral floating three-dimensional (3D) display methods are proposed for implementing an augmented reality (AR) system. The 3D display for AR requires a long-range focus depth and a see-though property. A system that adopts a concave lens instead of a convex lens is proposed for realizing the integral floating system with a long working distance using a reduced pixel pitch of the elemental image. An investigation that reveals that the location of the central depth plane is restricted by the pixel pitch of the display device is presented. An optical see-through system using a convex half mirror is also proposed for providing 3D images with a proper accommodation response. The concepts of the proposed methods are explained and the validity of system is proved by the experimental results. © 2012 Optical Society of America.

Lee Y.H.,Hanyang University | Kim D.H.,Hanyang University | Yoo K.-H.,Kyung Hee University | Kim T.W.,Hanyang University
Applied Physics Letters | Year: 2014

Organic light-emitting devices (OLEDs) were fabricated utilizing Au-ZnO nanocomposites (NCs) with various Au nanoparticles (NPs) concentrations synthesized by using a sol-gel process to enhance their current efficiency, and these devices were compared with OLEDs fabricated utilizing ZnO NPs only. The electroluminescence intensity of the OLEDs with Au-ZnO NCs at a wavelength of 535 nm was significantly larger than that of the OLEDs with ZnO NPs by a factor of 1.89. The current efficiency of the OLEDs with 10 wt.% Au-ZnO NCs at 1000 cd/m2 was higher by 16.7 cd/A than that of the OLEDs with ZnO NPs. This increase in the current efficiency of the OLEDs with Au-ZnO NCs was attributed to an enhancement of the out-coupling efficiency due to the existence of the localized surface plasmonic resonance effect induced by the Au NPs that were embedded in the Au-ZnO NCs. © 2014 AIP Publishing LLC.

Ashoorioon A.,Lancaster University | Sheikh-Jabbari M.M.,Institute for Research in Fundamental Sciences | Sheikh-Jabbari M.M.,Kyung Hee University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

In view of the recent BICEP2 results [arXiv:1403.3985] which may be attributed to the observation of B-modes polarization of the CMB with tensor-to-scalar ratio r=0.2-0.05 +0.07, we revisit M-flation model. Gauged M-flation is a string theory motivated inflation model with Matrix valued scalar inflaton fields in the adjoint representation of a U(N) Yang-Mills theory. In continuation of our previous works, we show that for a class of M-flation models the action for these inflaton fields can be such that the "effective inflaton field" ϕ has a double-well Higgs-like potential, with minima at ϕ=0, μ. We focus on the ϕ>μ, symmetry-breaking region. We thoroughly examine predictions of the model for r in the 2σ region allowed for nS by the Planck experiment. As computed in [arXiv:0903.1481], for Ne=60 and nS=0.96 we find r≃0.2, which sits in the sweet spot of BICEP2 region for r. We find that with increasing μ arbitrarily, nS cannot go beyond ≃0.9670, the scalar spectral index for the quadratic chaotic potential. As nS varies in the 2σ range which is allowed by Planck and could be reached by the model, r varies in the range [0.13, 0.26]. Future cosmological experiments, like the CMBPOL, that confines nS with σ(nS)=0.0029 can constrain the model further. Also, in this region of potential, for nS=0.9603, we find that the largest isocurvature mode, which is uncorrelated with curvature perturbations, has a power spectrum with the amplitude of order 10-11 at the end of inflation. We also discuss the range of predictions of r in the hilltop region, ϕ<μ. © 2014 The Authors.

Kim N.,Kyung Hee University | Kim N.,Institute for Advanced Study
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2013

We compute the holographic entanglement entropy for confining gauge theories with matter fields using the formula of Ryu and Takayanagi. The gravity solutions of our interest are the wrapped D5-brane solutions of Maldacena and Nunez, and the generalizations with extra matter fields. We obtain the relation between the entanglement entropy vs. size of the subsystem, and find that the critical length is increased as we add more matter fields. © 2013 Elsevier B.V.

Yoon P.H.,University of Maryland University College | Yoon P.H.,Kyung Hee University
Physics of Plasmas | Year: 2012

The suprathermal electron distributions with non-Maxwellian tail are commonly detected in space environment as well as in the laboratory. In a previous article [P. H. Yoon, Phys. Plasmas 18, 122303 (2011)], a self-consistent theory of asymptotically steady-state electron distribution function and Langmuir turbulence intensity was formulated in which the steady-state electron distribution is obtained by balancing the spontaneous (or collisional) drag term and velocity space diffusion term, while the steady-state turbulence intensity was obtained by balancing spontaneous and induced processes. The resulting electron distribution function was a type of kappa distribution that features a non-Maxwellian energetic tail component. However, such a discussion was based upon the assumption that both electrons and Langmuir waves are confined to one-dimensional space along the direction of the implicit ambient magnetic field. However, such an assumption may be invalidated when the implicit ambient magnetic field is sufficiently weak or absent. Consequently, in this paper the assumption of one-dimensionality is relaxed to three-dimensional situation. © 2012 American Institute of Physics.

With the adoption of national health insurance in 1977, Korea has been utilizing fee-forservice payment with contract-based healthcare reimbursement system in 2000. Under the system, fee-for-service reimbursement has been accused of augmenting national healthcare expenditure by excessively increasing service volume. The researcher examined in this paper two major alternatives including diagnosis related group-based payment and global budget to contemplate the future of reimbursement system of Korean national health insurance. Various literature and preceding studies on pilot project and actual implementation of Neo-KDRG were reviewed. As a result, DRG-based payment was effective for healthcare cost control but low in administrative efficiency. Global budget may be adequate for cost control and improving the quality of healthcare and administrative efficiency. However, many healthcare providers disagree that excess care arising from fee-for-service payment alone has led to financial deterioration of national health insurance and healthcare institutions should take responsibility with global budget payment as an appropriate solution. Dissimilar payment systems may be applied to different types of institutions to reflect their unique attributes, and this process can be achieved step-by-step. Developing public sphere among the stakeholders and striving for consensus shall be kept as collateral to attain the desirable reimbursement system in the future. © 2012 The Korean Academy of Medical Sciences.

Yeh Y.,Kyung Hee University | Park S.H.,Andong National University
Optics Letters | Year: 2012

In order to implement a fiber-optic Fabry-Perot tunable filter with a simple configuration, a concave mirror is made at the end of the optical fiber. The concave mirror is fabricated by attaching a thin polycarbonate (PC) film on the fiber end, pressing the PC film with a fiber ball to form a dimple, and then depositing a multilayer dielectric mirror. The concave mirror aligned to the fiber core makes the cavity alignment easy with a simple alignment configuration. Because of the self-alignment function of this cavity, a small, reliable, and fast filter could be fabricated. © 2012 Optical Society of America.

In order to understand the configuration of magnetic field producing a solar penumbral microjet that was recently discovered by Hinode, we performed a magnetohydrodynamic simulation reproducing a dynamic process of how that configuration is formed in a modeled solar penumbral region. A horizontal magnetic flux tube representing a penumbral filament is placed in a stratified atmosphere containing the background magnetic field that is directed in a relatively vertical direction. Between the flux tube and the background field there forms the intermediate region in which the magnetic field has a transitional configuration, and the simulation shows that in the intermediate region magnetic reconnection occurs to produce a clear jet-like structure as suggested by observations. The result that a continuous distribution of magnetic field in three-dimensional space gives birth to the intermediate region producing a jet presents a new view about the mechanism of a penumbral microjet, compared to a simplistic view that two field lines, one of which represents a penumbral filament and the other the background field, interact together to produce a jet. We also discuss the role of the intermediate region in protecting the structure of a penumbral filament subject to microjets. © 2010 The American Astronomical Society. All rights reserved.

Jang S.E.,Kyung Hee University
Journal of microbiology and biotechnology | Year: 2013

Lactic acid bacteria (LAB) in fermented foods have attracted considerable attention recently as treatment options for immune diseases, the incidence of which has been increasing worldwide. The ability of 500 strains of LAB, isolated from kimchi, to induce TNF--α production in peritoneal macrophages was investigated. Lactobacillus plantarum HY7712 most strongly induced TNF--α production as well as NF-κB activation. However, HY7712 inhibited NF-κB activation in LPS-stimulated peritoneal macrophages. When HY7712 was orally treated in cyclophosphamide (CP)-immunosuppressed mice for 5 or 15 days, it reversed the body and spleen weights, blood RBC and WBC levels, and splenocyte and bone marrow cells that were reduced by CP. Orally administered HY7712 increased concanavalin A-induced T cell proliferation to 84.5% of the normal group on day 15, although treatment with CP alone markedly reduced it to 53.7% of the normal group. Furthermore, orally administered HY7712 significantly induced the expressions of IL-2 and IFN-γ in ConA-induced splenic cytotoxic T cells of CP-treated mice. Orally administered HY7712 restored the CP-impaired phagocytosis of macrophages in mice. Orally administered HY7712 also restored the cytotoxicity of NK and cytotoxic T cells derived from spleen and bone marrow against YAC-1 in CP-immunosuppressed mice. Based on these findings, orally administered HY7712 may accelerate the recovery of cyclophosphamide-caused immunosuppression, without evident side effects, by immunopotentiating NK and Tc cells, and may provide a mechanistic basis for using HY7712 as an alternative means in lessening chemotherapyinduced immunosuppression in cancer patients.

Hong J.-W.,Kyung Hee University | Park K.W.,Sungkyunkwan University | Levine M.S.,University of California at Berkeley
Developmental Biology | Year: 2013

Differentiation of a specific organ or tissue requires sequential activation of regulatory genes. However, little is known about how serial gene expression is temporally regulated. Here, we present evidence that differential expression of single-minded (sim) target genes can be attributed, in part, to the number of Sim and Tango (Tgo) heterodimer binding sites within their enhancer regions. The Sim, termed a master regulator, directs ventral midline differentiation of Drosophila central nervous system (CNS). According to data on the onset timing of ventral midline gene expression, sim target genes are classified into at least 2 groups (early and late). The sim and rhomboid (rho) genes are activated during early midline differentiation whereas orthodenticle (otd), CG10249, and slit (sli) genes undergo activation during later stages of midline differentiation. Germline transformation and in situ hybridization with transgenic embryos demonstrate that enhancers activating sim and rho expression contain 4 Sim-Tgo binding sites whereas only 1 Sim-Tgo binding site is found in an enhancer of sli. A mutagenized version of the rho enhancer lacking either 1, 2, or 3 Sim-Tgo binding sites mediated progressively more delayed expression of a lacZ reporter gene in the ventral midline. In contrast, a modified sli enhancer displayed progressively earlier onset of lacZ expression when 1, 2, or 3 more Sim-Tgo binding sites were added. Taken together, these results suggest that the number of Sim-Tgo-binding sites is decisive in determining the timing of gene expression in the developing ventral midline. We also discuss a combinatorial model accounting for the sequential expression of sim target genes. © 2013 Elsevier Inc.

We theoretically investigate the effect of multichannel pump injection on the ultrafast gain and phase recovery dynamics of quantum-dot (QD) semiconductor optical amplifiers (SOAs) by solving 10880 coupled rate equations. The ultrafast gain and phase recovery responses induced by three-channel pump injection are calculated compared with the single-channel pump injection. The gain and phase recovery response caused by three-channel pump injection is different from the summation of the three gain and phase recovery responses induced by separate single-channel pump injection. We identify the physical mechanism of the distinct gain and phase recovery responses due to different pump wavelength by considering the interplay between the Lorentzian line shape function and the spectral spacing between the pump and probe beams. The calculation results help to understand the gain and phase recovery dynamics of QD SOAs for multichannel amplification in coarse wavelength division multiplexing (CWDM) applications. © 2012 The Japan Society of Applied Physics.

Alishahiha M.,Institute for Research in Fundamental Sciences | Yavartanoo H.,Kyung Hee University
Journal of High Energy Physics | Year: 2012

We study certain features of strongly coupled theories with hyperscaling violation by making use of their gravitational duals. We will consider models with an anisotropic scaling in time or in one of spatial directions. In particular for the case where the anisotropic scaling is along a spatial direction we will compute the holographic entanglement entropy and show that for specific values of the parameters it exhibits a logarithmic violation of the area law. We will also probe the backgrounds by different closed and open strings which in turn can be used to read, for example, effective potential of an external object, drag force and etc. © SISSA 2012.

Alishahiha M.,Institute for Research in Fundamental Sciences | Colgain E.O.,University of Oviedo | Yavartanoo H.,Kyung Hee University
Journal of High Energy Physics | Year: 2012

We present an analytic solution of a charged black hole with hyperscaling violating factor in an Einstein-Maxwell-Dilaton model where the scalar potential is key to the existence of a solution. This solution provides a candidate gravitational description of theories with hyperscaling violation at both finite temperature and finite charge density. Using this background we explore certain features of these theories via AdS/CFT correspondence. Finally, we discuss embeddings based on the well-known sphere reductions of ten and eleven-dimensional supergravity. © 2012 SISSA, Trieste, Italy.

Park S.K.,Sungkyunkwan University | Seo M.H.,Sungkyunkwan University | Shin H.C.,Sungkyunkwan University | Ryoo J.-H.,Kyung Hee University
Hepatology | Year: 2013

There have been several reports about the clinical association between type 2 diabetes mellitus (DM) and nonalcoholic fatty liver disease (NAFLD). However, most of the studies were about the unilateral effects of type 2 DM on NAFLD, and studies on the reverse relation are rare. Thus, this study was designed to investigate the effect of NAFLD on type 2 DM. We conducted a prospective cohort study on 25,232 Korean men without type 2 DM for 5 years. We serially checked the various metabolic factors including fasting glucose and hemoglobin A1c (HbA1c), and monitored the development of type 2 DM. The incidence rate of type 2 DM was compared according to the degree of NAFLD (normal, mild, and moderate to severe), and a Cox proportional hazards model was used to measure the hazard ratios (HRs) of NAFLD on type 2 DM. The incidence rate of type 2 DM increased according to the degree of NAFLD (normal: 7.0%, mild: 9.8%, moderate to severe: 17.8%, P < 0.001). Even after adjusting for other multiple covariates, the HRs (95% confidence interval [CI]) for type 2 DM development was higher in the mild group (1.09; 0.81-1.48) and moderate to severe group (1.73; 1.00-3.01) compared to the normal group, respectively (P for trend <0.001). Conclusion: The development of type 2 DM is potentially more associated with more progressive NAFLD than a normal or milder state. In addition, NAFLD was an independent risk factor for the future development of type 2 DM. These results suggest the potential availability of NAFLD as an early predictor of type 2 DM. © 2012 American Association for the Study of Liver Diseases.

Park C.-W.,Korea Railroad Research Institute | Lee H.-S.,Kyung Hee University
Computers and Operations Research | Year: 2011

The system we address is a maintenance network of repairable items where a set of bases is supported by a centrally located repair depot and a consumable replacement parts inventory system. If an item fails, a replacement part must be obtained at the parts inventory system before the failed item enters the repair depot. The ordering policy for the parts is the (S,Q) inventory policy. An approximation method for this system is developed to obtain performance measures such as steady-state probabilities of the number of items at each site and the expected backorders at the parts inventory system. The proposed system is modelled as a multi-class closed queueing network with a synchronization station and analyzed using a product-form approximation method. Particularly, the product-form approximation method is adapted so that the computational effort on estimating the parameters of the equivalent multi-class network is minimized. In analyzing a sub-network, a recursive method is used to solve balance equations by exploiting the special structure of the Markov chain. Numerical tests show that the approximation method provides fairly good estimation of the performance measures of interests. © 2011 Elsevier Ltd.

Singh V.,Deakin University | Gu N.,University of Newcastle | Wang X.,University of Sydney | Wang X.,Kyung Hee University
Automation in Construction | Year: 2011

Most complex projects in the Architecture, Engineering, and Construction (AEC) industries involve multi-disciplinary collaboration and the exchange of large building data set. Traditionally, the collaboration efforts across the disciplines have been based on the frequent exchange of 2D drawings and documents. However, during the past decade, the widespread adoption of object-oriented Computer-aided Design (CAD) tools has generated more interests in Building Information Modelling (BIM). A number of BIM-compliant applications such as analysis tools, model checkers and facility management applications are being developed. This paper develops a theoretical framework of technical requirements for using BIM-server as a multi-disciplinary collaboration platform. The methodologies that are used to develop the framework include focus group interviews (FGIs) with representatives from the diverse AEC disciplines, a case study of an Architectural project using a state-of-the-art BIM-server, and a critical review and analysis of current collaboration platforms that are available to the AEC industries. This paper concludes that greater emphasis should be placed on supporting technical requirements to facilitate technology management and implementation across disciplines. Their implications for user-centric technology development in design and construction industry are also discussed. © 2010 Elsevier B.V.

Choi E.M.,Kyung Hee University
International Immunopharmacology | Year: 2012

Liquiritigenin is one of the flavonoids present in Glycyrrhizae radix. In the present study, the effects of liquiritigenin on the function of osteoblastic MC3T3-E1 cells were studied. Liquiritigenin caused a significant elevation of cell growth, alkaline phosphatase activity, collagen synthesis, mineralization, and glutathione content in the cells (P < 0.05). Moreover, liquiritigenin significantly decreased the production of reactive oxygen species (ROS) and osteoclast differentiation inducing factors such as tumor necrosis factor α (TNF-α), interleukin-6 (IL-6), and receptor activator of nuclear factor-κB ligand (RANKL) in the presence of antimycin A, which inhibits mitochondrial electron transport and has been used as a ROS generator. These results demonstrate that liquiritigenin may have positive effects on skeletal structure. © 2011 Elsevier B.V. All rights reserved.

Lee C.,U.S. National Cancer Institute | Kim K.P.,Kyung Hee University | Long D.J.,University of Florida | Bolch W.E.,University of Florida
Medical Physics | Year: 2012

Purpose: To establish an organ dose database for pediatric and adolescent reference individuals undergoing computed tomography (CT) examinations by using Monte Carlo simulation. The data will permit rapid estimates of organ and effective doses for patients of different age, gender, examination type, and CT scanner model. Methods: The Monte Carlo simulation model of a Siemens Sensation 16 CT scanner previously published was employed as a base CT scanner model. A set of absorbed doses for 33 organstissues normalized to the product of 100 mAs and CTDIvol (mGy100 mAs mGy) was established by coupling the CT scanner model with age-dependent reference pediatric hybrid phantoms. A series of single axial scans from the top of head to the feet of the phantoms was performed at a slice thickness of 10 mm, and at tube potentials of 80, 100, and 120 kVp. Using the established CTDIvol- and 100 mAs-normalized dose matrix, organ doses for different pediatric phantoms undergoing head, chest, abdomen-pelvis, and chest-abdomen-pelvis (CAP) scans with the Siemens Sensation 16 scanner were estimated and analyzed. The results were then compared with the values obtained from three independent published methods: CT-Expo software, organ dose for abdominal CT scan derived empirically from patient abdominal circumference, and effective dose per dose-length product (DLP). Results: Organ and effective doses were calculated and normalized to 100 mAs and CTDI vol for different CT examinations. At the same technical setting, dose to the organs, which were entirely included in the CT beam coverage, were higher by from 40 to 80 for newborn phantoms compared to those of 15-year phantoms. An increase of tube potential from 80 to 120 kVp resulted in 2.5-2.9-fold greater brain dose for head scans. The results from this study were compared with three different published studies andor techniques. First, organ doses were compared to those given by CT-Expo which revealed dose differences up to several-fold when organs were partially included in the scan coverage. Second, selected organ doses from our calculations agreed to within 20 of values derived from empirical formulae based upon measured patient abdominal circumference. Third, the existing DLP-to-effective dose conversion coefficients tended to be smaller than values given in the present study for all examinations except head scans. Conclusions: A comprehensive organeffective dose database was established to readily calculate doses for given patients undergoing different CT examinations. The comparisons of our results with the existing studies highlight that use of hybrid phantoms with realistic anatomy is important to improve the accuracy of CT organ dosimetry. The comprehensive pediatric dose data developed here are the first organ-specific pediatric CT scan database based on the realistic pediatric hybrid phantoms which are compliant with the reference data from the International Commission on Radiological Protection (ICRP). The organ dose database is being coupled with an adult organ dose database recently published as part of the development of a user-friendly computer program enabling rapid estimates of organ and effective dose doses for patients of any age, gender, examination types, and CT scanner model. © 2012 American Association of Physicists in Medicine.

Kang W.S.,Kyung Hee University
Molecular biology reports | Year: 2012

The α-amino-3-hydroxy-5-methyl-4-propionic acid (AMPA) receptors are important for glutamate synaptic transmission in the central nervous system. Glutamate receptor, ionotropic, AMPA receptor 1 gene (GRIA1) belongs to the family of AMPA receptors. There is increasing evidence that AMPA receptors dysfunction may be related to an increased susceptibility to schizophrenia. The aim of this study was therefore to investigate whether genetic polymorphisms of GRIA1 are associated with schizophrenia and their clinical symptoms (hallucinations and delusions) in Korean population. Five single nucleotide polymorphisms (rs1428920, rs1552834, rs1422889, rs10035143, and rs2926835) of the GRIA1 were genotyped in 218 schizophrenia patients and 380 healthy controls, using a direct sequencing. All patients were evaluated by the Operational Criteria Checklist for Psychotic Illness. The genotype and allelic frequencies of rs1428920 and rs2926835 showed significant association between schizophrenia and controls (rs1428920, permutation p = 0.008, 0.008; rs2926835, permutation p = 0.038, 0.041, respectively). A significantly increased risk of schizophrenia was associated with the A allele of rs1428920 and rs2926835 of GRIA1. Furthermore, we found that rs1428920 was weakly associated with hallucinations of schizophrenia, but this significance disappeared after multiple testing (permutation p = 0.119). These results suggest that GRIA1 polymorphism may have influence upon the risk of developing schizophrenia.

Kim J.E.,Kyung Hee University
Nuclear and Particle Physics Proceedings | Year: 2016

Discrete symmetries allowed in string compactification are the mother of all global symmetries which are broken at some level. We discuss the resulting pseudo-Goldstone bosons, in particular the QCD axion and a temporary cosmological constant, and inflatons. We also comment on some implications of the recent BICEP2 data. © 2015 Elsevier B.V..

Kim J.S.,Kyung Hee University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2016

We provide evidence for the validity of strong monogamy inequality of multiparty quantum entanglement using the square of convex-roof extended negativity (SCREN). We first consider a large class of multiqudit mixed states that are in a partially coherent superposition of a generalized W-class state and the vacuum, and provide some useful properties about this class of states. We show that monogamy inequality of multiqudit entanglement in terms of SCREN holds for this class of states. We further show that SCREN strong monogamy inequality of multiqudit entanglement also holds for this class of states. Thus SCREN is a good alternative for characterizing the monogamous and strongly monogamous properties of multiqudit entanglement. © 2016 American Physical Society.

Islam M.S.,Chonbuk National University | Kang S.H.,Kyung Hee University
Talanta | Year: 2011

A novel, quantitative analytical method for measuring C-reactive protein (CRP) levels in human serum has been developed based on the catalytic activity of gold nanoparticles (GNPs) and luminol-H 2O 2 chemiluminescence (CL). The CL intensity in the presence of CRP and its ligand, O-phosphorylethanolamine (PEA), was greatly enhanced due to the aggregation of GNPs after the addition of 0.5 M NaCl. Any pretreatment steps, such as covalent functionalization of GNPs, addition of antibodies, or labeling of CRP, were not needed for CL detection. The CL enhancement was linearly proportional to CRP concentration in the range of 1.88 fM to 1.925 pM. The detection limit of CRP in serum samples was estimated to be as low as 1.88 fM. The detection sensitivity was increased more than 164 times of magnitude over that of the conventional, enzyme-linked immunosorbent assay (ELISA) method. This proposed GNP-based CL detection method offers the advantages of simplicity, rapidity, and sensitivity. © 2011 Elsevier B.V. All rights reserved. All rights reserved.

Alzheimer's disease (AD) is the most common cause of progressive dementia and is characterized by memory impairments, neuronal death, and neuroinflammation. AD-related pathophysiology is caused primarily by the presence of amyloid-β oligomers (AβO). Recently, an increased focus has been directed toward natural compounds or medicinal extracts for the treatment of AD. Extracts from Bombycis excrementum (BE), which is composed of various bioactive constituents and mulberry leaves (the preferred food of silkworms), have been shown to possess anti-inflammatory, anti-diabetic, and anti-oxidative effects. Additionally, mulberry leaves exert anti-amyloidogenic action and neuroprotective effects against Aβ peptides but it is unknown whether BE has a therapeutic effect on AD-related pathologies. Therefore, the present study examined whether BE inhibits AβO-induced memory loss, neuronal death, and inflammation. Behavioral tests revealed that BE significantly ameliorated AβO-induced memory impairments and inhibited AβO-induced neuronal loss in cultured cells and the brains of mice. BE also significantly inhibited microgliosis and astrogliosis following intra-hippocampal AβO injections in mice. Furthermore, BE significantly attenuated the release of nitric oxide from microglia and reduced AβO-induced S100-β cytokine release from activated astrocytes. These results suggest that BE may be a candidate agent for the treatment of AD.

Moon J.-Y.,Kyung Hee University
Electrolyte and Blood Pressure | Year: 2013

The activation of renin-angiotensin-aldosterine system (RAAS) is one of the main pathogenesis of hypertension. All the components of RAAS are present in the kidneys at higher concentrations compared to plasma levels, and intrarenal formation of angiotensin II (Ang II) is independent of the systemic RAAS. There are some unique features in intrarenal RAAS compared to systemic RAAS. Unlike JG cells where Ang II inhibits renin release via the AngII type 1 (AT1) receptor by negative feedback, in the collecting duct Ang II stimulates renin expression via the AT1 receptor. Upregulated renin produced in the distal nephron may be able to support continued intrarenal Ang II formation leading to amplification or maintenance of the hypertensive state. The recently discovered angiotensin-converting enzyme-related carboxypeptidase 2 (ACE2)-Angiotensin-(1- 7) Ang-(1-7)] -Mas receptor axis has an opposing function to that of the ACE-Ang II-AT1 receptor axis. The ACE2 deficiency was associated with an increase in blood pressure, and ACE2 knockout mice have highlighted hypertensive response to Ang II infusion associated with exaggerated accumulation of Ang II in the kidney. Recently, several numbers of patients have been evaluated as the activators of ACE2-Ang-(1-7)-Mas receptor axis, which can be divided into two main classes: aimed to increase the activity of ACE2, and directed to stimulate the Ang-(1-7) receptor Mas. In order to investigate new targets for hypertension and kidney disease, further research on the function of the ACE-Ang-(1-7)-Mas receptor axis is required. Copyright © 2013 The Korean Society of Electrolyte Metabolism.

Kim N.,Kyung Hee University | Kim N.,Institute for Advanced Study
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

For supersymmetric solutions of D3-(M2-) branes with AdS 3(AdS 2) factor, it is known that the internal space is expressible as U(1) fibration over Kähler space which satisfies a specific partial differential equation involving the Ricci tensor. In this paper we study the wrapped brane solutions of D3- and M2-branes, which were originally constructed using gauged supergravity and uplifted to D=10 and D=11. We rewrite the solutions in canonical form, identify the backreacted Kähler geometry, and present a class of solutions which satisfy the Killing spinor equation. © 2012 American Physical Society.

Seo J.K.,Yonsei University | Woo E.J.,Kyung Hee University
IEEE Transactions on Biomedical Engineering | Year: 2014

The tomographic imaging of tissue's electrical properties (e.g., conductivity and permittivity) has been greatly improved by recent developments in magnetic resonance (MR) imaging techniques, which include MR electrical impedance tomography (MREIT) and electrical property tomography. When the biological material is subjected to an external electric field, local changes in its electrical properties become sources of magnetic field perturbations, which are detectable by the MR signals. Controlling the external excitation and measuring the responses using an MRI scanner, we can formulate the imaging problem as an inverse problem in which unknown tissue properties are recovered from the acquired MR signals. This inverse problem is nonlinear; it involves the incorporation of Maxwell's equations and Bloch equations during data acquisition. Each method for visualizing internal conductivity and permittivity distributions has its own methodological limitations, and is restricted to imaging only a part of the ensemble or mean tissue structures or states. Therefore, imaging methods can be improved by developing complementary methods that can employ the beneficial aspects of various existing techniques. This paper focuses on recent progress in MREIT and discusses its distinct features in comparison with other imaging methods. © 1964-2012 IEEE.

Kim S.,Ajou University | Im S.H.,Kyung Hee University | Kim S.-W.,Ajou University
Nanoscale | Year: 2013

Light-emitting diodes (LEDs) based on colloidal quantum dots (QDs) have attracted considerable attention due to their potential in applications such as color-saturated displays and white light with high color-rendering index. However, cadmium-based QD-LEDs are strictly regulated in industrial applications because of the high toxicity of cadmium. As an alternative, InP-based cadmium-free QDs are recommended owing to their wide emission range that is comparable to that of CdSe, and their environmentally friendly properties when applied to QD-LEDs and white QD-LEDs. This feature article provides an overview of QDs' merits in display and light-emitting applications as well as a discussion of their color tunability, photo-stability, and high luminescence efficiency. We will include optical down-conversion devices using various QDs, electroluminescent devices based on organic and inorganic charge-transporting layers, and printing methods using cadmium based and cadmium free QDs. © 2013 The Royal Society of Chemistry.

Tu F.,University of Pennsylvania | Park B.J.,University of Pennsylvania | Park B.J.,Kyung Hee University | Lee D.,University of Pennsylvania
Langmuir | Year: 2013

One of the most important properties of emulsions is their stability. Most emulsions stabilized with molecular surfactants tend to lose their stability over time via different mechanisms. Although the stability of emulsions stabilized with homogeneous particles have been shown to be superior to that of surfactant-stabilized emulsions, these Pickering emulsions nevertheless are only kinetically stable and thus can undergo destabilization. Janus particles that have two opposite wetting surfaces have shown promise in imparting emulsions with long-term stability because of their strong attachment to the oil-water interface. In this theoretical study, we consider thermodynamics of emulsion stabilization using amphiphilic Janus dumbbells, which are nonspherical particles made of two partially fused spherical particles of opposite wettability. These amphiphilic dumbbells are attractive candidates as colloid surfactants for emulsion stabilization because highly uniform Janus dumbbells can be synthesized in large quantities; thus, their application in emulsion stabilization can become practical. Our theoretical calculation demonstrates that Janus dumbbells can indeed generate thermodynamically stable Pickering emulsions. In addition, we also find that there exists a total oil-water interfacial area that results in the lowest energy state in the system, which occurs when Janus dumbbells available in the system are completely consumed to fully cover the droplet interfaces. We show that the geometry of dumbbells as well as the composition of the emulsion mixtures has significant influences on the average size of dumbbell-stabilized emulsions. We also investigate the effect of asymmetry of Janus dumbbells on the average droplet radius. Our results clearly show that amphiphilic Janus dumbbells provide unique opportunities in stabilizing emulsions for various applications. © 2013 American Chemical Society.

Je Y.,Kyung Hee University
Archives of Gynecology and Obstetrics | Year: 2015

Purpose: Acrylamide has been associated with carcinogenicity in experimental animals, but potential health risks of dietary acrylamide intake and endometrial cancer in human are inconclusive. Thus, a meta-analysis of prospective cohort studies was conducted to provide a quantitative assessment of the association between dietary acrylamide intake and endometrial cancer risk. Methods: PubMed database was used to identify prospective cohort studies on dietary acrylamide intake and endometrial cancer risk published up to June 2014. Since smoking is an important source of acrylamide and is inversely associated with endometrial cancer risk, the association was examined in women who never smoked as well. Multivariable relative risks (RR) adjusting for potential confounders were combined using random effects models. Results: Four large prospective cohort studies were identified, which included 453,355 female participants and 2,019 endometrial cancer cases. There was no association between dietary acrylamide intake and endometrial cancer risk overall [pooled RR for high vs. low intake = 1.10; 95 % confidence interval (CI) 0.91–1.34]. High acrylamide intake, however, was significantly associated with increased risk of endometrial cancer among women who never smoked (pooled RR for high vs. low intake = 1.39; 95 % CI 1.09–1.77). In dose–response analyses, pooled RRs for an increase of 10 µg/day were 1.04 (95 % CI 0.97–1.11) among all women and 1.11 (95 % CI 1.04–1.19) among never-smoking women. Conclusions: Endometrial cancer risk was not associated with dietary acrylamide intake overall. Among women who never smoked, however, there was a significantly increased endometrial cancer risk in women who consumed high dietary acrylamide. © 2014, Springer-Verlag Berlin Heidelberg.

Park C.-J.,University of California at Davis | Ronald P.C.,University of California at Davis | Ronald P.C.,Kyung Hee University
Nature Communications | Year: 2012

Plants and animals carry specific receptors that recognize invading pathogens and respond by activating an immune response. The rice XA21 receptor confers broad-spectrum immunity to the Gram-negative bacterial pathogen, Xanthomonas oryzae pv. oryzae upon recognition of a small protein, Ax21, that is conserved in all Xanthomonas species and related genera. Here we demonstrate that XA21 is cleaved to release the intracellular kinase domain and that this intracellular domain carries a functional nuclear localization sequence. Bimolecular fluorescence complementation assays indicate that the XA21 intracellular domain interacts with the OsWRKY62 transcriptional regulator exclusively in the nucleus of rice protoplasts. In vivo cleavage of XA21 and translocalization of the intracellular kinase domain to the nucleus is required for the XA21-mediated immune response. These results suggest a new model for immune receptor function: on receptor recognition of conserved microbial signatures, the associated kinase translocates to the nucleus where it directly interacts with transcriptional regulators. © 2012 Macmillan Publishers Limited. All rights reserved.

Lee D.,Kyung Hee University | Kim H.S.,University of Alabama | Kim J.K.,Kyungsung University
Computers in Human Behavior | Year: 2012

The current study reconceptualized self-construal as a social cognitive indicator of self-observation that individuals employ for developing and maintaining social relationship with others. From the social cognitive perspective, this study investigated how consumers' self-construal can affect consumers' electronic word of mouth (eWOM) behavior through two cognitive factors (online community engagement self-efficacy and social outcome expectations) in the context of a social networking site. This study conducted an online experiment that directed 160 participants to visit a newly created online community. The results demonstrated that consumers' relational view became salient when the consumers' self-construal was primed to be interdependent rather than independent. Further, the results showed that such interdependent self-construal positively influenced consumers' eWOM behavioral intentions through their community engagement self-efficacy and their social outcome expectations. © 2012 Elsevier Ltd. All rights reserved.

Hwang Y.,DePaul University | Hwang Y.,Kyung Hee University
Computers in Human Behavior | Year: 2012

This paper investigates the moderating effects of collectivist cultural orientation introduced in the information systems and knowledge management (KM) literature to fully understand the important factors and relationships in knowledge sharing in the online learning environment. Social norms and collectivist cultural orientation are hypothesized as direct and moderating factors to the system users' (or learners') attitude toward sharing knowledge by email. An empirical test of large student samples (n = 566) with multiple cultural backgrounds in the most diverse university was implemented by PLS. The test confirmed that collectivist cultural orientation moderates the effects of social norms on the attitude toward sharing knowledge by email. Furthermore, the test results show that group norms are stronger than the instructor or classmate norms. Theoretical and practical implications of these findings for online learning and KM are discussed in the paper. © 2012 Elsevier Ltd. All rights reserved.

Photoassimilated carbons are converted to sucrose in green plant leaves and distributed to non-phototropic tissues to provide carbon and energy. In photosynthetic sucrose biosynthesis, the chloroplast envelope triose phosphate/phosphate translocator (TPT) and cytosolic fructose-1,6-bisphosphatase (cFBPase) are key components in photosynthetic sucrose biosynthesis. The simultaneous overexpression of TPT and cFBPase was utilized to increase the source capacity of Arabidopsis. The TPT and cFBPase overexpression lines exhibited enhanced growth with larger rosette sizes and increased fresh weights compared with wild-type (WT) plants. The simultaneous overexpression of TPT and cFBPase resulted in enhanced photosynthetic CO(2) assimilation rates in moderate and elevated light conditions. During the phototropic period, the soluble sugar (sucrose, glucose, and fructose) levels in the leaves of these transgenic lines were also higher than those of the WT plants. These results suggest that the simultaneous overexpression of TPT and cFBPase enhances source capacity and consequently leads to growth enhancement in transgenic plants. © Springer Science+Business Media B.V. 2012

Ghatalia P.,University of Alabama at Birmingham | Je Y.,Kyung Hee University | Kaymakcalan M.D.,Dana-Farber Cancer Institute | Sonpavde G.,Medical Center | Choueiri T.K.,Dana-Farber Cancer Institute
British Journal of Cancer | Year: 2015

Background: Multi-targeted vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitors (TKIs) are known to cause cardiac toxicity, but the relative risk (RR) of QTc interval prolongation and serious arrhythmias associated with them are not reported. Methods: We conducted a trial-level meta-analysis of randomised phase II and III trials comparing arms with and without a US Food and Drug Administration-approved VEGFR TKI (sunitinib, sorafenib, pazopanib, axitinib, vandetanib, cabozantinib, ponatinib and regorafenib). A total of 6548 patients from 18 trials were selected. Statistical analyses were conducted to calculate the summary incidence, RR and 95% CIs. Results: The RR for all-grade and high-grade QTc prolongation for the TKI vs no TKI arms was 8.66 (95% CI 4.92-15.2, P<0.001) and 2.69 (95% CI 1.33-5.44, P=0.006), respectively, with most of the events being asymptomatic QTc prolongation. Respectively, 4.4% and 0.83% of patients exposed to VEGFR TKI had all-grade and high-grade QTc prolongation. On subgroup analysis, only sunitinib and vandetanib were associated with a statistically significant risk of QTc prolongation, with higher doses of vandetanib associated with a greater risk. The rate of serious arrhythmias including torsades de pointes did not seem to be higher with highgrade QTc prolongation. The risk of QTc prolongation was independent of the duration of therapy. Conclusions: In the largest study to date, we show that VEGFR TKI can be associated with QTc prolongation. Although most cases were of low clinical significance, it is unclear whether the same applies to patients treated off clinical trials. © 2015 Cancer Research UK. All rights reserved.

Namkung Y.,Kyung Hee University | Jang S.S.,Purdue University
International Journal of Hospitality Management | Year: 2013

This study examines the effects of green practices at restaurants on customer-based brand equity formation. A survey of 512 American diners showed that implementing two aspects of green practices, food focused and environmentally focused, influenced customer perceptions of green brand image and behavioral intentions, whereas the effects of green practices on perceived quality were not significant. The relative impact of the two aspects of green practices differs by restaurant type. In upscale casual dining restaurants, green practices focused on foods were more effective in enhancing a green brand image and behavioral intentions as compared to those with an environmental focus. On the other hand, for casual dining customers the effects of green practices with an environmental focus were more convincing in terms of improving a restaurant's green brand image and behavioral intentions as compared to food focused initiatives. In relation to self-perception, the results indicated that diners with high health and environmental-consciousness responded more positively to restaurant green practices than those with a low self-perception of health and environmental-consciousness. © 2012 Elsevier Ltd.

Back K.-J.,University of Houston | Back K.-J.,Kyung Hee University
International Journal of Hospitality Management | Year: 2012

The objective of this study is to assess the key-drivers of customer satisfaction and dissatisfaction and their asymmetric effects in the formation of customer satisfaction and dissatisfaction in Korean restaurants by using impact-range performance analysis (IRPA) and impact asymmetry analysis (IAA) approaches. Two hundred thirty-nine diners at two Korean restaurants in a U.S. southern metropolitan city participated in this study. Results validated the rigor of IRPA and IAA for identifying key determining factors and assessing magnitude among various restaurants' attributes. Food taste, presentation, cleanliness, and fair price had severe impacts on CS. The theoretical and practical implications of this study's findings are included to enrich both academicians' and restaurant industry professionals' understanding of customers' perceptions of and attitudes toward restaurants, and development of a marketing strategy. © 2011 Elsevier Ltd.

Kim J.E.,Kyung Hee University | Kim J.E.,Center for Axion and Precision Physics Research
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2016

Heavy axion-like particles, called axizillas, are simple extensions of the standard model (SM). An axizilla is required not to couple to the quarks, leptons, and Brout-Englert-Higgs doublets of the SM, but couple to the gauge anomalies of the W±, Z and photon. It is possible to have its branching ratios (BRs) to two photons greater than 10% and to two Z's less than 10%. To have a (production cross section).(BR to di-photons) at a 10-38 cm2 level, a TeV scale heavy quark Q is required for the gluon-quark fusion process. The decay of Q to axizilla plus quark, and the subsequent decay of the axizilla to two photons can be fitted at the required level of 10-38 cm2. © 2016 The Author.

Kim J.E.,Kyung Hee University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2013

We show that Abelian discrete symmetries ZN and ZnR from string orbifolds result by assigning vacuum expectation values (VEVs) only to specified singlets. These singlets obtaining VEVs carry the gauge charges (of the covering U(1) gauge group) as multiples of N for ZN and n for ZnR. We explicitly show this realization in a Z12-I orbifold model. © 2013 Elsevier B.V.

Kim J.S.,Kyung Hee University
Annals of Physics | Year: 2016

We provide generalized entanglement constraints in multi-qubit systems in terms of Tsallis entropy. Using quantum Tsallis entropy of order q, we first provide a generalized monogamy inequality of multi-qubit entanglement for q=2 or 3. This generalization encapsulates the multi-qubit CKW-type inequality as a special case. We further provide a generalized polygamy inequality of multi-qubit entanglement in terms of Tsallis-q entropy for 1≤q≤2 or 3≤q≤4, which also contains the multi-qubit polygamy inequality as a special case. © 2016 Elsevier Inc.

Hong S.G.,Kyung Hee University
Nuclear Science and Engineering | Year: 2013

in this paper, two new subcell balance methods for solving the multigroup discrete ordinates transport equation in unstructured geometrical problems are presented. The problem domains are divided into tetrahedral meshes to model the complicated geometries. In these new methods, the angular flux and its flux moments are approximated with the four-term linear discontinuous expansion, and then, the unknowns (four point fluxes or subcell average fluxes) and the interface fluxes are represented in terms of the expansion coefficients. Finally, the external and internal interface average fluxes are represented in terms of the unknown fluxes, and the subcell balance equations give the complete relations associated with the unknown fluxes. Two ways for dividing a tetrahedral mesh into subcells are considered, and they lead to the new methods. The first subcell balance method, called LDEM-SCB(O), is relatively simple, and the second subcell balance method, called LDEM-SCB(l), is more complicated than LDEM-SCB(O). The point flux formulations of these methods can be easily implemented with minor modifications in the discontinuous finite element method codes. The numerical tests show that the new subcell balance methods provide accurate and robust solutions. In particular, the numerical analysis shows that LDEM-SCB(O) and LDEM-SCB(1) have first- and second-order accuracies, respectively, in the transport regime. Also, it was found from the asymptotic analysis that these methods satisfy the linear continuous diffusion discretizations on the interior in the thick diffusion limit.

Lee J.,Seoul National University | Kwon J.E.,Seoul National University | You Y.,Kyung Hee University | Park S.Y.,Seoul National University
Langmuir | Year: 2014

A novel salicylidene aniline-based wholly π-conjugated molecule that could be self-assembled into an organogel was synthesized. The rigid organogel collapsed into fluid solutions with significant changes in UV-vis absorption and fluorescence colors in response to fluoride ions. It was found that the hydroxyl group in the salicylidene aniline moiety played a key role not only in the gelation but also in fluoride ion responses. © 2014 American Chemical Society.

Kim Y.-R.,Kyung Hee University | Aragao F.T.S.,Federal University of Rio de Janeiro
Finite Elements in Analysis and Design | Year: 2013

This paper presents a computational microstructure model to predict the fracture-related behavior of heterogeneous and viscoelastic bituminous paving mixtures. In addition to the consideration of the complex geometric characteristics and viscoelastic behavior of the mixture, this study implements a rate-dependent cohesive zone model into the mainframe of ABAQUS in the form of a customized user element (UEL) subroutine. This enables model fracture as a gradual and rate-dependent phenomenon in which the initiation and propagation of discrete cracks take place in the mixture microstructure. In order to validate the model, experimental programs are developed for model inputs and outputs, and microstructural simulations of a two-phase mixture specimen are conducted. Model simulation results agree well with test results. The results presented in this paper imply that a computational microstructure model such as the one herein can be an efficient tool to estimate the effects of small-scale design variables on overall mixture performance with significant savings in experimental costs and time. © 2012 Elsevier B.V. All rights reserved.

Min K.,New Jersey Institute of Technology | Lee J.,New Jersey Institute of Technology | Lee J.,Kyung Hee University | Keika K.,New Jersey Institute of Technology | Li W.,University of California at Los Angeles
Journal of Geophysical Research: Space Physics | Year: 2012

Electromagnetic ion cyclotron (EMIC) waves play an important role in magnetospheric dynamics and their global distribution has been of great interest. This paper presents the distribution of EMIC waves over a broader range than ever before, as enabled by observations with the Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft from 2007 to 2010. Our major findings are: (1) There are two major peaks in the EMIC wave occurrence probability. One is at dusk and 8-12 RE where the helium band dominates the hydrogen band waves. The other is at dawn and 10-12 RE where the hydrogen band dominates the helium band waves. (2) In terms of wave spectral power the dusk events are stronger (≈10 nT 2/Hz) than the dawn events (≈3 nT2/Hz). (3) The dawn waves have large normal angles (>45°) in the hydrogen band and even larger normal angles (>60°) in the helium band. The dusk waves have small normal angles (≤30°) in both the hydrogen and helium bands. (4) The hydrogen band waves at dawn are weakly left-hand polarized near the equator, become linearly polarized with increasing latitude and eventually weakly right-hand polarized at high latitudes whereas the helium band waves at dawn are linearly polarized at all latitudes. Dusk waves in both bands are strongly left-hand polarized over a wide range of latitude. Based on the linear EMIC instability model presented by Horne and Thorne (1994), we suggest that the main underlying factor for the observed spatial variations of these wave properties would be local density of cold plasma and chemical abundance. In addition, the distinct properties of H and He band waves found in this study would deserve a new attention in relation to EMIC wave generation mechanisms. Copyright 2012 by the American Geophysical Union.

Kim N.,Kyung Hee University
Modern Physics Letters A | Year: 2013

We consider general supersymmetric Wilson loops in ABJM model, which is Chern-Simons-matter theory in (2+1) dimensions with N = 6 supersymmetry. The Wilson loops of our interest are so-called Zarembo-type: they have generic contours in spacetime, but the scalar field coupling is arranged accordingly so that there are unbroken supersymmetries. Following the supermatrix construction of Wilson loops by Drukker and Trancanelli and the generalization by Griguolo et al., we study 1/6-BPS Wilson loops and check that their expectation value is protected using perturbation up to two loops. We also study the dual string configuration in AdS4×ℂℙ3 background and check the supersymmetry. © World Scientific Publishing Company.

Seo Y.,Korea Expressway Corporation | Kim S.-M.,Kyung Hee University
Renewable and Sustainable Energy Reviews | Year: 2013

The first attempt has been made in Korea to quantify the carbon dioxide (CO2) emitted from the consumption of main and basic materials for road, bridge and tunnel constructions. These materials-induced CO2 emissions were estimate using the amount of materials consumed and corresponding CO2 emission factors. A simple linear relation was developed between unit price and emission factor for some of basic materials whose emission factors were not available. To demonstrate overall and unit emissions, twelve expressway sections constructed between 2006 and 2007 have been selected and consumed materials have been identified. The unit emissions were then utilized to estimate the total emissions that might have been released from all types of roads (expressways, national highways and local roads) up to the year 2007. Also, the effects of number of traffic lanes and bridge types on the CO 2 emissions were briefly discussed. Finally, average annual CO 2 emissions were predicted based on road construction plans from 2009 to 2020. One of the results suggested that bridges should induce the largest emissions per meter (120.1 tCO2/m), followed by tunnels (29.6 tCO2/m) and road-only sections (7.5 tCO2/m) due to the consumption of main construction materials. © 2013 Elsevier Ltd.

Kim C.N.,Kyung Hee University
Fusion Science and Technology | Year: 2013

A three-dimensional liquid metal magnetohydro-dynamic (LMMHD) flow in a manifold with three subchannels under a uniform magnetic field has been examined based on the computational fluid dynamics method. Although numerous analytic, experimental, and numerical studies on LMMHD duct flows have been performed, detailed flow characteristics of a LMMHD flow in a manifold with multiple channels have not been studied much. In the current study detailed behaviors of the fluid velocity, pressure, current, and electric potential of LMMHD flows in a manifold with three subchannels under a uniform magnetic field are elucidated. Also, an imbalance of mass flow rates in the three subchannels is addressed.

Han H.,Dongguk University | Tai Kim J.,Kyung Hee University
Energy | Year: 2010

A fiber optic solar concentrator system with a simple parabolic profile is designed and fabricated to deliver a stream of high-density solar flux into the interior of a building for indoor illumination. The system consists of a small dish concentrator (30 cm in diameter), an optical fiber cable and a diffuser at the end. A series of tests are performed using a goniophotometer and spectrometer to investigate the photometric characteristics of the system in terms of luminous intensity distribution and spectral radiance, which are used in link with the actual photometric measurements for a lightless mock-up space of 4.9 m × 4.9 m × 2.6 m. The illuminance on the working plane was continuously monitored at 25 points by using photometric sensors. Measurements clearly indicate the photometric characteristics of the present system where a constant level of indoor illumination is observed depending on the sky clearness. © 2009 Elsevier Ltd. All rights reserved.

Ban J.Y.,Dankook University | Yoo K.H.,Kyung Hee University
International Neurourology Journal | Year: 2014

Purpose: Benign prostatic hyperplasia (BPH) is the most common prostate disease in aging men. Microseminoprotein-beta (MSMB) is abundant in semen. In this study, we investigated association between single nucleotide polymorphisms (SNPs) at the promoter of the MSMB gene and the risk for developing BPH in a Korean population. Methods: We genotyped two promoter polymorphisms (rs12770171, -184C/T and rs10993994, -2C/T) of the MSMB gene by direct sequencing. Ninety-five BPH patients and 78 control subjects were recruited for this study. SNPStats and Haploview version 4.2 were used for genetic analyses. Multiple logistic regression models (codominant, dominant, recessive, and log-additive models) were applied to determine the odds ratio (OR), 95% confidence interval (CI), and P-value. Results: Genotype frequency of the rs12770171 SNP showed significant difference between BPH patients and controls (OR, 2.14; 95% CI, 1.07-4.27; P=0.032 in the codominant 1 model; OR, 2.31; 95% CI, 1.19-4.47; P=0.011 in the dominant model; and OR, 2.05; 95% CI, 1.17-3.61; P=0.009 in the log-additive model). Moreover, the SNP also showed association between the two groups (OR, 2.05; 95% CI, 1.19-3.52; P=0.009). The rs10993994 SNP was not associated with BPH. In haplotype analysis, CC and TT haplotypes were associated with BPH (P<0.05). Conclusions: This result indicates that a promoter polymorphism (rs12770170, -184C/T) in the MSMB gene may be associated with BPH development in a Korean population. © 2014 Korean Continence Society.

Lee H.,Kyung Hee University
Journal of Mathematical Physics | Year: 2013

In this paper, the Vlasov-Poisson-Boltzmann system is studied in the context of Newtonian cosmology. An explicit background solution which describes the evolution of our universe is constructed, and global existence of homogeneous solutions that are perturbations around the background solution is obtained. Depending on the rate of expansion of the universe it is observed that the solutions have different behaviours at a large time. At a slow rate of expansion the solutions tend to an equilibrium state, but it turns out that such a slow rate is not physically well-motivated. At a rapid rate of expansion it is showed that the solutions behave like solutions of the Vlasov equation. © 2013 AIP Publishing LLC.

Ha T.-L.,Kyung Hee University | Kim J.G.,Pohang University of Science and Technology | Kim S.M.,Pohang University of Science and Technology | Lee I.S.,Pohang University of Science and Technology
Journal of the American Chemical Society | Year: 2013

Annealing of MnO@SiO2 nanospheres in a reducing gas environment resulted in the transformation of the core-shell structure into a hollow structure as a result of outward diffusion of MnO species into the thermodynamically more stable silicate phase. When the hollow silicate nanospheres were oxidized, the interior cavities were refilled with a Mn 3O4 phase segregated from the silicate phase, and the hollow structure reverted to the initial core-shell structure. More interestingly, when catalytically active Pt nanocrystals were introduced into the manganese oxide/silica system, the Mn3O4 was readily reduced to the chemically reactive MnO, even at low temperature, which enabled reconversion of the solid nanospheres with a Mn3O4 core to hollow nanostructures during reductive annealing. Therefore, when MnO@SiO 2Pt(II) nanospheres were subjected to an oxidation/reduction cycle by repeatedly switching the flowing gas between air and hydrogen, the nanospheres underwent a reversible change between solid and hollow structures, depending on the gas environment. The solid-to-hollow-to-solid transformation was successfully cycled many times simply by repeatedly switching the flowing gas during annealing. © 2012 American Chemical Society.

Sivasubramanian M.,Kyung Hee University | Thambi T.,Sungkyunkwan University | Park J.H.,Sungkyunkwan University
Carbohydrate Polymers | Year: 2013

The extensive therapeutic potential of protein drugs has been severely limited by their instability and short biological half-lives in vivo. To prolong their therapeutic effects, a sustained delivery system is required. In this study, cyclodextrin-based polymeric nanoparticles (CD-NPs), mineralized by calcium phosphate as the diffusion barrier, were developed as a carrier for sustained protein delivery. Spherical CD-NPs were readily prepared by a conjugate, composed of β-CD as the protein-binding moiety and carboxymethyl dextran as the substrate for mineralization in a physiological solution. Owing to the presence of carboxylic acids in CD-NPs, they were effectively mineralized by sequential addition of calcium nitrate and ammonium phosphate. The physicochemical characteristics of mineralized CD-NPs were characterized using FT-IR, thermogravimetric analysis, transmission electron microscopy and energy dispersive X-ray photoelectron spectroscopy. Mineralization reduced CD-NP particle size from 310 nm to 121 nm in PBS (pH 7.4) indicating the formation of compact nanoparticles. Carbonic anhydrase B (CAB), chosen as the model protein, was loaded into the mineralized CD-NPs with a high loading efficiency (80%) by a simple dialysis method. In vitro release tests showed that CAB was completely released from bare CD-NPs in 3 days. Interestingly, the mineralized CD-NPs released CAB in a sustained manner for 21 days, which was due to the stable calcium phosphate barrier inhibiting CAB release. The enzymatic activity of CAB, which was released from the nanoparticles, did not significantly deteriorate compared to native CAB. Overall, mineralized CD-NPs could be a promising carrier for sustained protein delivery. © 2013 Elsevier Ltd. All rights reserved.

The essential oil of Pinus koraiensis (EOPK) is biologically active compound obtained from the leaves of P. koraiensis. The goal of this study was to investigate the anti-cancer mechanism of EOPK in HCT116 colorectal cancer cells. HCT116 cell proliferation was assessed by conducting crystal violet and BrdU assays. To assess the effects of EOPK on cell migration, we performed a wound-healing assay. Further, the contribution of PAK1 to EOPK-induced AKT and extracellular signal-regulated kinase (ERK) suppression was assessed by siRNA-mediated PAK1 knockdown. Changes to the expression and phosphorylation of PAK1 and its effectors were determined by western blotting, and changes to the actin cytoskeleton were determined by performing an immunofluorescence assay. EOPK significantly decreased HCT116 cell proliferation and migration, and induced G1 arrest without affecting normal cells. Additionally, EOPK suppressed the expression of PAK1, and decreased ERK and AKT phosphorylation in HCT116 cells. Finally, EOPK suppressed β-catenin, cyclin D1, and CDK4/6 expression. Our studies indicate that EOPK significantly reduced proliferation and migration of colorectal cancer cells. Furthermore, EOPK suppressed PAK1 expression in a dose-dependent manner, and this suppression of PAK1 led to inhibition of ERK, AKT, and β-catenin activities. Our findings suggest that EOPK exerts its anticancer activity via the inhibition of PAK1 expression, suggesting it may be a potent chemotherapeutic agent for colorectal cancer.

Shim J.-J.,Kyung Hee University
Clinical Endoscopy | Year: 2012

Endoscopic ultrasound (EUS) is a useful diagnostic tool for evaluation of esophagogastric varices and guidance of endoscopic therapy. EUS can visualize not only collateral veins around the esophagus but also perforating veins that connect esophageal varices with collateral veins. They are associated with high risk of bleeding and early recurrence after initial variceal eradication. Isolated gastric varices can be easily diagnosed using EUS that mimic thickened gastric folds or subepithelial tumors. EUS-guided endoscopic therapy is a challenging field of variceal bleeding. It has a potential role for assistance of interventions and evaluation of treatment outcome. © 2012 Korean Society of Gastrointestinal Endoscopy.

Pode R.,Kyung Hee University
Renewable and Sustainable Energy Reviews | Year: 2010

Energy plays the most vital role in the economic growth and security of any nation. Future economic growth crucially depends on the long-term availability of energy from sources that are affordable, accessible and environmental friendly. Acute energy scarcity in India in recent years is hampering its industrial growth and economic progress. India is strongly dependent on the fossil fuels for its energy requirements which are also contributing significantly to greenhouse gases emissions. It is proposed that the introduction of renewable energy sources portfolio to the future energy mix and diversification of fuel sources will (i) enhances energy security and mitigates CO2 emission, and (ii) improves the quality of life. If India failed to protect its environment, not only its economic growth would be impeded but also would pose serious health hazards. © 2010 Elsevier Ltd. All rights reserved.

With the widespread application of endoscopic submucosal dissection for the treatment of gastrointestinal neoplasms, accurate determination of the invasion depth prior to intervention has become an indispensable part of treatment planning. Narrow-band imaging (NBI) is a novel endoscopic technique that may enhance the accuracy of diagnosis. Magnifying endoscopy with NBI has been shown to be effective for determining invasion depth for intrapapillary capillary loop classification of esophageal cancer and microvascular pattern of stomach cancer. Such precise pre-treatment staging of early neoplastic lesions in the gastrointestinal tract warrants timely initiation of diseasetailored treatment and, ultimately, better quality of life and improved patient survival. © 2012 Korean Society of Gastrointestinal Endoscopy.

Solanki S.K.,Max Planck Institute for Solar System Research | Solanki S.K.,Kyung Hee University | Krivova N.A.,Max Planck Institute for Solar System Research | Haigh J.D.,Imperial College London
Annual Review of Astronomy and Astrophysics | Year: 2013

The brightness of the Sun varies on all timescales on which it has been observed, and there is increasing evidence that this has an influence on climate. The amplitudes of such variations depend on the wavelength and possibly the timescale. Although many aspects of this variability are well established, the exact magnitude of secular variations (going beyond a solar cycle) and the spectral dependence of variations are under discussion. The main drivers of solar variability are thought to be magnetic features at the solar surface. The climate response can be, on a global scale, largely accounted for by simple energetic considerations, but understanding the regional climate effects is more difficult. Promising mechanisms for such a driving have been identified, including through the influence of UV irradiance on the stratosphere and dynamical coupling to the surface. Here, we provide an overview of the current state of our knowledge, as well as of the main open questions. Copyright ©2013 by Annual Reviews. All rights reserved.

Moon J.-Y.,Kyung Hee University
Electrolyte and Blood Pressure | Year: 2011

The recently discovered angiotensin-converting enzyme-related carboxypeptidase 2 (ACE2)-[Angiotensin-(1-7)(Ang-(1-7)]-Mas receptor axis has an opposing function to that of the ACE-Anglotensln II (Ang II)-Angiotensin type 1 (AT1) receptor axis. Ang-(1-7) is present in the kidneys at concentrations comparable to those of Ang II and is associated with vasodilation, modulation of sodium and water transport, and stimulation of nitric oxide (NO) synthase. Ang-(1-7) also acts as a physiological antagonist of Ang II by counterbalancing the Ang II-mediated intracellular signaling pathway. In a hypertensive model, increased ACE and decreased ACE2 along with a higher ACE/ACE2 ratio in hypertensive kidneys appeared to favor Ang II generation, leading to hypertensive renal damage. In addition, the administration of a selective Ang-(1-7) receptor blocker or an ACE2 inhibitor was associated with worsening of hypertension and renal function. Ang-(1-7)-mediated increases in renal blood flow were abolished by blockade of the Mas receptor and by inhibition of prostaglandin release and NO in spontaneously hypertensive rats and in Wistar-Kyoto controls. Further research on the function of the ACE2-Ang-(1-7)-Mas receptor axis could lead to a novel target for inhibiting kidney disease progression. Copyright © 2011 The Korean Society of Electrolyte Metabolism.

Lee K.Y.,Sungkyunkwan University | Kumar B.,Sungkyunkwan University | Seo J.-S.,Sungkyunkwan University | Kim K.-H.,Sungkyunkwan University | And 5 more authors.
Nano Letters | Year: 2012

Enhancing the output power of a nanogenerator is essential in applications as a sustainable power source for wireless sensors and microelectronics. We report here a novel approach that greatly enhances piezoelectric power generation by introducing a p-type polymer layer on a piezoelectric semiconducting thin film. Holes at the film surface greatly reduce the piezoelectric potential screening effect caused by free electrons in a piezoelectric semiconducting material. Furthermore, additional carriers from a conducting polymer and a shift in the Fermi level help in increasing the power output. Poly(3-hexylthiophene) (P3HT) was used as a p-type polymer on piezoelectric semiconducting zinc oxide (ZnO) thin film, and phenyl-C 61-butyric acid methyl ester (PCBM) was added to P3HT to improve carrier transport. The ZnO/P3HT:PCBM-assembled piezoelectric power generator demonstrated 18-fold enhancement in the output voltage and tripled the current, relative to a power generator with ZnO only at a strain of 0.068%. The overall output power density exceeded 0.88 W/cm 3, and the average power conversion efficiency was up to 18%. This high power generation enabled red, green, and blue light-emitting diodes to turn on after only tens of times bending the generator. This approach offers a breakthrough in realizing a high-performance flexible piezoelectric energy harvester for self-powered electronics. © 2012 American Chemical Society.

Liu N.,Korea University | Kim P.,Korea University | Kim J.H.,Korea University | Ye J.H.,Korea University | And 2 more authors.
ACS Nano | Year: 2014

Molybdenum disulfide (MoS2) is an extremely intriguing material because of its unique electrical and optical properties. The preparation of large-area and high-quality MoS2 nanosheets is an important step in a wide range of applications. This study demonstrates that monolayer and few-layer MoS2 nanosheets can be obtained from electrochemical exfoliation of bulk MoS2 crystals. The lateral size of the exfoliated MoS2 nanosheets is in the 5-50 μm range, which is much larger than that of chemically or liquid-phase exfoliated MoS2 nanosheets. The MoS2 nanosheets undergo low levels of oxidation during electrochemical exfoliation. In addition, microscopic and spectroscopic characterizations indicate that the exfoliated MoS2 nanosheets are of high quality and have an intrinsic structure. A back-gate field-effect transistor was fabricated using an exfoliated monolayer MoS2 nanosheet. The on/off current ratio is over 106, and the field-effect mobility is approximately 1.2 cm2 V-1 s-1; these values are comparable to the results for micromechanically exfoliated MoS2 nanosheets. The electrochemical exfoliation method is simple and scalable, and it can be applied to exfoliate other transition metal dichalcogenides. © 2014 American Chemical Society.