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Incheon, South Korea

Inha University ) is a private research university located in Incheon, South Korea.Known traditionally for research and education in the engineering and physical science, the University was established by the first president of South Korea, Syngman Rhee. It is a Korean-American collaboration school, even in its name: the Morpheme "In" comes from the city of Incheon and "Ha" comes from Hawaii, USA. At first time, it started as a technical college, named Inha Institute of Technology .Currently, Inha is ranked 10th nationwide, and especially 4th in Engineering and Science, by JoongAng Ilbo's annual ranking of South Korean universities. Inha is a member of GU8. Wikipedia.

Yun S.,Kyung Hee University | Kang S.-O.,Kyung Hee University | Park S.,Inha University | Park H.S.,Kyung Hee University
Nanoscale | Year: 2014

Herein, we demonstrate CO2-activated macroscopic graphene architectures with trimodal pore systems that consist of 3D inter-networked macroporosity arising from self-assembly, mesoporosity arising from the intervoids of nanosheets, and microporosity via CO2 activation. The existence of micropores residing in hierarchical structures of trimodal porous graphene frameworks (tGFs) contributes to greatly improve the surface area and pore volume, which are ∼3.8 times greater than typical values of existing 3D macroporous graphene monoliths. As confirmed by the specific capacity, the kinetic parameters, and the regeneration capability for chemical adsorption as well as the specific capacitance, the rate capability, and the cycle stability for electrochemical energy storage, the tGFs have an ideal texture for high performance capacitive materials. Furthermore, the tGFs obtain the structurally and energetically homogeneous surface active sites, which dominantly operate through the π-π interactions for adsorption. Consequently, the ultrahigh capacitance and ultrafast capacitive performance of the tGFs for both chemical and electrochemical adsorptions are attributed to hierarchical trimodal porosity and surface chemistry. These results offer a chemical approach combining self-assembly with conventional activation for the construction of 3D hierarchical structures with multimodal porosity. This journal is © the Partner Organisations 2014.

Kim L.,Inha University | Tsao M.S.,University of Toronto
European Respiratory Journal | Year: 2014

In the era of personalised cancer therapy, the demand for molecular profiling of the patient's tumour is steadily increasing. In advanced nonsmall cell lung cancer (NSCLC) patients, testing for epidermal growth factor receptor (EGFR) mutations and anaplastic lymphoma kinase (ALK) gene rearrangements has become an essential component of clinical practice to select patients who are most likely to benefit from EGFR and ALK tyrosine kinase inhibitors, respectively. Furthermore, obtaining tissue specimens from recurrent or metastatic tumours or from patients who develop resistance to initial effective therapies are essential for our understanding of the molecular basis of tumour progression and development of drug resistance. Therefore, the sampling of tumour tissue that is representative and is adequate in quantity and quality for pathological diagnosis and genomic profiling is crucial. In this review, we will discuss factors that should be considered in obtaining and processing biopsy specimens to enable routine molecular analysis in NSCLC patients. Copyright © 2014 ERS.

Moon S.,Catholic University of Korea | Yang S.-G.,Meet You | Yang S.-G.,Inha University | Na K.,Catholic University of Korea
Biomaterials | Year: 2011

Gemcitabine (Gem) eluting metal stents were prepared for potential application as drug delivery systems for localized treatment of malignant tumors. Pullulan, a natural polysaccharide, was chemically acetylated (pullulan acetate; PA) by different degrees (1.18, 1.71, and 2.10 acetyl groups per glucose unit of pullulan), layered on polytetrafluoroethylene (PTFE), and applied as part of a Gem-loaded controlled-release membrane for drug-eluting non-vascular stents. PA with a higher degree of acetylation had greater drug-loading capacity with more extended release of Gem over 30 days. The released Gem accumulated in CT-26 colon cancer without systemic exposure inducing total regression of tumors. The long-term biological activity of the released Gem and apoptosis of tumor tissues following localized delivery were confirmed by annexin V binding assays and histology. The controlled release of Gem from PA-PTFE covered drug-eluting stents (DES) may increase the patency of these stents for the treatment of malignant gastrointestinal cancer as well as cancer-related stenosis. © 2011 Elsevier Ltd.

Hye Kim J.,Yonsei University | Gyu Park S.,Korea University | Gyu Park S.,Ajou University | Kim W.-K.,Yonsei University | And 2 more authors.
Stem Cells | Year: 2015

Platelet-derived growth factor-D (PDGF-D) was recently identified, and acts as potent mitogen for mesenchymal cells. PDGF-D also induces cellular transformation and promotes tumor growth. However, the functional role of PDGF-D in adipose-derived stem cells (ASCs) has not been identified. Therefore, we primarily investigated the autocrine and paracrine roles of PDGF-D in this study. Furthermore, we identified the signaling pathways and the molecular mechanisms involved in PDGF-D-induced stimulation of ASCs. It is of interest that PDGF-B is not expressed, but PDGF-D and PDGF receptor-β are expressed in ASCs. PDGF-D showed the strongest mitogenic effect on ASCs, and PDGF-D regulates the proliferation and migration of ASCs through the PI3K/Akt pathways. PDGF-D also increases the proliferation and migration of ASCs through generation of mitochondrial reactive oxygen species (mtROS) and mitochondrial fission. mtROS generation and fission were mediated by p66Shc phosphorylation, and BCL2-related protein A1 and Serpine peptidase inhibitor, clade E, member 1 mediated the proliferation and migration of ASCs. In addition, PDGF-D upregulated the mRNA expression of diverse growth factors such as vascular endothelial growth factor A, fibroblast growth factor 1 (FGF1), FGF5, leukemia inhibitory factor, inhibin, beta A, interleukin 11, and heparin-binding EGF-like growth factor. Therefore, the preconditioning of PDGF-D enhanced the hair-regenerative potential of ASCs. PDGF-D-induced growth factor expression was attenuated by a pharmacological inhibitor of mitogen-activated protein kinase pathway. In summary, PDGF-D is highly expressed by ASCs, where it acts as a potent mitogenic factor. PDGF-D also upregulates growth factor expression in ASCs. Therefore, PDGF-D can be considered a novel ASC stimulator, and used as a preconditioning agent before ASC transplantation. © 2014 AlphaMed Press.

Kim N.R.,Yonsei University | Kim N.R.,Inha University | Lim H.,Yonsei University | Kim J.H.,Yonsei University | And 3 more authors.
Ophthalmology | Year: 2011

Purpose: To determine the factors that contribute to false-positive retinal nerve fiber layer (RNFL) color code results from spectral-domain optical coherence tomography (OCT). Design: A prospective, cross-sectional study. Participants: This study included 149 eyes from 77 healthy participants. Methods: Participants, who were consecutively enrolled from June 2009 to December 2009, underwent Cirrus OCT. Recorded demographic and clinical factors included age, gender, eye side, intraocular pressure, central corneal thickness, spherical equivalent, axial length, anterior chamber depth, disc area, and the extent of retinal vasculature. Main Outcome Measures: An abnormal finding in RNFL color codes was defined as <1 yellow or red sectors by quadrant and clock-hour maps and a wedge-shaped color pattern represented by yellow or red in the deviation map. The incidence of false-positive color codes was determined. The influence of clinical and demographic factors on the incidence of false-positive RNFL color codes was assessed using generalized linear mixed model analysis. Results: The false-positive rate for <1 of the quadrant, clock-hour, and deviation maps was 26.2%. Longer axial length and smaller disc area were significantly associated with an increased incidence of false-positives when other factors were controlled (odds ratios, 2.422 and 0.165; P = 0.008 and 0.035, respectively). Conclusions: The factors that significantly affected the false-positive RNFL color code results using spectral-domain OCT were axial length and disc area, which may significantly affect the specificity of spectral-domain OCT. Therefore, axial length and disc area should be considered during RNFL thickness profile analysis. Financial Disclosure(s): Proprietary or commercial disclosure may be found after the references. © 2011 American Academy of Ophthalmology.

Kwon M.-J.,Ewha Womans University | Jang B.,Ewha Womans University | Yi J.Y.,Korea Institute of Radiological and Medical Sciences | Han I.-O.,Inha University | Oh E.S.,Ewha Womans University
FEBS Letters | Year: 2012

Syndecan are a family of cell surface heparan sulfate proteoglycans that act as cell surface receptors. Most cell surface receptors have a limited number and type of ligand interactions, responding only to the binding of (a) specific ligand(s). In contrast, syndecans can interact with various numbers and types of ligands, and thus play more diverse roles than others. Various syndecan functions have not yet been fully classified and categorized, but we herein review previous studies suggesting that syndecans play dual function as cell surface receptors by acting as both adhesion receptors and docking receptors. Through this dual regulatory function, syndecans are capable of regulating both intra- and extracellular activities, potentially altering a variety of cell behaviors. Crown Copyright © 2012 Published by Elsevier B.V. on behalf of Federation of European Biochemical society. All rights reserved.

Kang J.-H.,University of Pennsylvania | Kang J.-H.,Inha University | Vanderstichele H.,ADx Neurosciences | Trojanowski J.Q.,University of Pennsylvania | Shaw L.M.,University of Pennsylvania
Methods | Year: 2012

The xMAP-Luminex multiplex platform for measurement of Alzheimer's disease (AD) cerebrospinal fluid (CSF) biomarkers using Innogenetics AlzBio3 immunoassay reagents that are for research use only has been shown to be an effective tool for early detection of an AD-like biomarker signature based on concentrations of CSF Aβ 1-42, t-tau and p-tau 181. Among the several advantages of the xMAP-Luminex platform for AD CSF biomarkers are: a wide dynamic range of ready-to-use calibrators, time savings for the simultaneous analyses of three biomarkers in one analytical run, reduction of human error, potential of reduced cost of reagents, and a modest reduction of sample volume as compared to conventional enzyme-linked immunosorbant assay (ELISA) methodology. Recent clinical studies support the use of CSF Aβ 1-42, t-tau and p-tau 181 measurement using the xMAP-Luminex platform for the early detection of AD pathology in cognitively normal individuals, and for prediction of progression to AD dementia in subjects with mild cognitive impairment (MCI). Studies that have shown the prediction of risk for progression to AD dementia by MCI patients provide the basis for the use of CSF Aβ 1-42, t-tau and p-tau 181 testing to assign risk for progression in patients enrolled in therapeutic trials. Furthermore emerging study data suggest that these pathologic changes occur in cognitively normal subjects 20 or more years before the onset of clinically detectable memory changes thus providing an objective measurement for use in the assessment of treatment effects in primary treatment trials. However, numerous previous ELISA and Luminex-based multiplex studies reported a wide range of absolute values of CSF Aβ 1-42, t-tau and p-tau 181 indicative of substantial inter-laboratory variability as well as varying degrees of intra-laboratory imprecision. In order to address these issues a recent inter-laboratory investigation that included a common set of CSF pool aliquots from controls as well as AD patients over a range of normal and pathological Aβ 1-42, t-tau and p-tau 181 values as well as agreed-on standard operating procedures (SOPs) assessed the reproducibility of the multiplex methodology and Innogenetics AlzBio3 immunoassay reagents. This study showed within-center precision values of 5% to a little more than 10% and good inter-laboratory %CV values (10-20%). There are several likely factors influencing the variability of CSF Aβ 1-42, t-tau and p-tau 181 measurements. In this review, we describe the pre-analytical, analytical and post-analytical sources of variability including sources inherent to kits, and describe procedures to decrease the variability. A CSF AD biomarker Quality Control program has been established and funded by the Alzheimer Association, and global efforts are underway to further define optimal pre-analytical SOPs and best practices for the methodologies available or in development including plans for production of a standard reference material that could provide for a common standard against which manufacturers of immunoassay kits would assign calibration standard values. © 2012 Elsevier Inc.

Choi S.,Jeju National University | Kim M.K.,Inha University | Kim G.M.,Jeju National University | Roh Y.-H.,Jeju National University | And 2 more authors.
Journal of Shoulder and Elbow Surgery | Year: 2014

Background: This study was conducted to evaluate clinical outcomes, maintenance of repair integrity, and retear rate after arthroscopic rotator cuff repair by a suture bridge technique among patients with medium, large, and massive rotator cuff tears. Methods: We evaluated 147 patients who had undergone arthroscopic rotator cuff repair. Clinical and functional evaluations were performed with the Constant and University of California-Los Angeles scores. All patients were confirmed to have magnetic resonance imaging evidence of tendon healing at least 12months postoperatively. Results: The average postoperative time to follow-up magnetic resonance imaging was 23.4months (range, 12-48months). A total of 25 (17.0%) retears were observed. All clinical outcome scores were improved significantly at follow-up. Larger intraoperative tear sizes were correlated with higher retear rates. The incidence of retear was also higher in cases in which the preoperative fatty degeneration grade was higher. The incidence of retear increased with age and in the heavy worker group (e.g., farmers, carriers, car mechanics) but was not statistically significant. Conclusions: Arthroscopic rotator cuff repair by a suture bridge technique yields improvements in clinical outcome measures and a relatively high degree of patient satisfaction despite the fact that repair integrity is not maintained in many cases. © 2014 Journal of Shoulder and Elbow Surgery Board of Trustees.

Pai S.-Y.,Harvard University | Kim C.,Inha University | Williams D.A.,Harvard University
Disease Markers | Year: 2010

Rho GTPases are members of the Ras superfamily of GTPases that regulate a wide variety of cellular functions. While Rho GTPase pathways have been implicated in various pathological conditions in humans, to date coding mutations in only the hematopoietic specific GTPase, RAC2, have been found to cause a human disease, a severe phagocytic immunodeficiency characterized by life-threatening infections in infancy. Interestingly, the phenotype was predicted by a mouse knock-out of Rac2 and resembles leukocyte adhesion deficiency (LAD). Here we review Rho GTPases with a specific focus on Rac GTPases. In particular, we discuss a new understanding of the unique and overlapping roles of Rac2 in blood cells that has developed since the generation of mice deficient in Rac1, Rac2 and Rac3 proteins. We propose that Rac2 mutations leading to disease be termed LAD type IV. © 2010 - IOS Press and the authors. All rights reserved.

We investigate the effect of the synthetic antiferromagnetic polarizer layer rigidness on the switching current density of spin transfer torque magnetic tunneling junction with micromagnetic simulations. In contrary to the general belief, surprisingly, the rigidness of the polarizer layer affects to the spin dynamics of the free layer and it causes the switching current density changes. When the rigidness of the synthetic antiferromagnetic polarizer layer is weakened by reducing the interlayer exchange coupling energy, we found that the switching current density can be reduced due to the more effective switching process. © 2013 AIP Publishing LLC.

Kumaran R.S.,Konkuk University | Kim H.J.,Konkuk University | Hur B.-K.,Inha University
Journal of Bioscience and Bioengineering | Year: 2010

The endophytic fungi, Pestalotiopsis versicolor and Pestalotiopsis neglecta, were isolated from the healthy leaves and bark of the Japanese Yew tree, Taxus cuspidata. The fungal species were identified by their characteristic culture morphology and molecular analysis. For the first time, the test fungi were screened for the production of taxol in modified liquid medium. The presence of taxol was confirmed by HPLC, 1H NMR, and LC-MS methods of analysis. The maximum amount of taxol production in P. versicolor was recorded as 478μg/l. The production rate was increased to 9560-fold than that found in the culture broth of earlier reported fungus, Taxomyces andreanae. The extracted fungal taxol showed a strong cytotoxic activity in the in vitro culture of tested human cancer cells by apoptotic assay indicating that the increase in taxol concentration induces increased cell death. A PCR-based screening for ts, a unique gene in the formation of the taxane skeleton, confirmed the molecular blueprint for taxol biosynthesis. The results designate that the fungal endophyte, P. versicolor, is an excellent candidate for an alternate source of taxol supply and can also serve as a potential species for genetic engineering to enhance the production of taxol to a higher level. © 2010 The Society for Biotechnology, Japan.

Ryu H.-Y.,Inha University | Lee J.-M.,Electronics and Telecommunications Research Institute
Applied Physics Letters | Year: 2013

A light-emitting diode (LED) structure containing p-type GaN layers with two-step Mg doping profiles is proposed to achieve high-efficiency performance in InGaN-based blue LEDs without any AlGaN electron-blocking-layer structures. Photoluminescence and electroluminescence (EL) measurement results show that, as the hole concentration in the p-GaN interlayer between active region and the p-GaN layer increases, defect-related nonradiative recombination increases, while the electron current leakage decreases. Under a certain hole-concentration condition in the p-GaN interlayer, the electron leakage and active region degradation are optimized so that high EL efficiency can be achieved. The measured efficiency characteristics are analyzed and interpreted using numerical simulations. © 2013 AIP Publishing LLC.

A quadratic Volterra model with a finite nonlinear memory effect was introduced and applied to the time series prediction of a slender marine structure exposed to the Morison load. First, the unknown nonlinear single-input-single-output dynamic system was identified using the nonlinear autoregressive with exogenous input (NARX) technique based on the prepared datasets of the wave elevation and system response, which was obtained by running nonlinear time domain analysis for a certain short term sea state. The structure of NARX was designed in such a way that the linear part had infinite memory, whereas the nonlinear part had finite memory of a certain length. Second, the frequency domain Volterra kernels, both linear and quadratic, were derived analytically by applying the harmonic probing method to the identified system. To derive the frequency response functions, the sigmoidal function used in NARX to realize the nonlinear relationship between the input and output was expanded to polynomials based on the Taylor series expansion, so that the harmonics of same frequencies were easily matched between the input and output. Finally, the time series of the system response under arbitrarily given short term sea states were predicted using the quadratic Volterra series. The proposed methodology was used to predict the nonlinear dynamic response of a 2-dimentional free standing catenary riser exposed to a random ocean wave load, and the comparison between the prediction and simulation results was made on the probability distribution of the maximum excursion of riser top. The results show that the proposed methodology can successfully capture the nonlinear effects of the dynamic response of a slender marine structure induced by the quadratic term of the Morison formula. © 2015 Elsevier Ltd.

Lee M.,Eco Research Institute | Kim J.,Inha University
Separation and Purification Technology | Year: 2012

An analysis of local fouling in a pilot-scale submerged hollow-fiber membrane water treatment system for drinking water production is described in this paper. Membrane fouling was observed by using microscopic techniques with membrane specimen taken at different longitudinal and horizontal positions of a hollow-fiber membrane module. The resistance-in-series model was used to quantify local fouling resistances of membrane samples. Our results show that the recovery of the permeate flux of the hollow-fiber membrane located near the source of aeration was the highest after performing chemical cleaning. The irreversible fouling resistance was the largest for membrane samples taken near the open ends of the fibers, where the local pressure is expected to be highest. These axial features of irreversible fouling resistance were more pronounced at lower suspended solids concentration or higher set-point flux. However, the local aspect of reversible fouling was relatively less pronounced than the one of irreversible fouling. The results obtained from membrane autopsy were explained well by the local fouling phenomenon driven by the profile of local pressure along the fiber length and transient behavior of this profile during membrane operation. In addition, it was concluded that the individual membrane module experiencing more aeration would have a more localized pattern of membrane fouling, suggesting that the local fouling is more significant under relatively less demanding fouling conditions. © 2012 Elsevier B.V. All rights reserved.

Matos J.,Venezuelan Institute for Scientific Research | Garcia A.,Venezuelan Institute for Scientific Research | Park S.-E.,Inha University
Applied Catalysis A: General | Year: 2011

Photodegradation of methylene blue (MB) on Ti-containing mesoporous silica prepared by microwave-assisted irradiation as a function of Si/Ti molar ratio was studied. The materials were characterized by N2 adsorption, XRD, UV-vis/DR, and TEM. All solids showed mesoporous textures with high surface areas, relatively small pore size diameters and large pore volume. XRD showed that framework of solids consists of amorphous silica. It was found that the lower the Si/Ti ratio the higher the photocatalytic activity. Under irradiation with a lamp with more photons from visible light the sample with a Si/Ti ratio equal to 10 showed a higher photoactivity than that of a commercial TiO 2 photocatalyst. This result was in agreement with the UV-vis/DR spectra which showed that material with a Si/Ti = 10 has slightly higher energy band gap than that of commercial TiO2 suggesting that these materials behave as a photoactive semiconductor. © 2010 Elsevier B.V. All rights reserved.

Ryu H.-Y.,Inha University
Journal of the Korean Physical Society | Year: 2012

Based on the rate equation model of semiconductor lasers, the radiative efficiency and threshold current density of InGaN-based blue laser diodes (LDs) are theoretically investigated, including the effect of efficiency droop in the InGaN quantum wells. The peak point of the radiative efficiency versus current density relation is used as the parameter of the rate equation analysis. The threshold current density of InGaN blue LDs is found to depend strongly on the maximum radiative efficiency at low current density, implying that improving the maximum efficiency is important to maintain a high radiative efficiency at a large current density and to achieve a low-threshold lasing action under the influence of efficiency droop. © 2012 The Korean Physical Society.

An N.B.,Institute of Physics | Kim J.,Korea Institute for Advanced Study | Kim K.,Inha University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2011

We derive exact time evolution of three two-level atoms coupled to a common environment. The environment is structured and is modeled by a leaky cavity with Lorentzian spectral density. The atoms are initially prepared in a generalized W state and later on experience pairwise dipole-dipole interactions and couplings to the cavity. We study tripartite disentangling and entangling dynamics as well as protecting bipartite entanglement with both atom-atom interactions and atom-cavity couplings taken simultaneously into account. © 2011 American Physical Society.

Ryu H.-Y.,Inha University
Journal of the Korean Physical Society | Year: 2011

The light extraction efficiency (LEE) in GaN-based nanorod light-emitting diode (LED) structures is investigated using a three-dimensional (3-D) finite-difference time-domain (FDTD) simulation. The LED structure is composed of a p-GaN layer, InGaN/GaN active layers, and an n-GaN layer grown on a sapphire substrate, and the active layers are positioned at the center of the rods. The LEE for top or bottom emission shows a periodic behavior as the radius of a rod varies, which can be interpreted by the creation of radial resonant modes inside the nanorod cavity. The LEE in a nanorod array is found to be quite high. For an optimized nanorod LED structure, it can be >90%, which is higher than that of current high-efficiency LED structures by around 10%. Due to the potential of very high LEE, the nanorod LED structure is expected to be a good candidate for future high-efficiency LEDs.

Abstract The structural features related to the defects of LiMO2 (M Ni, Co, Mn) cathode materials for lithium secondary batteries were investigated by a simulation of phase diagrams based on first-principle calculations. Crystal models with various types of point defects were designed and dealt with as independent phases, which enabled an examination of the thermodynamic stability of the defects. A perfect phase without defects appeared to be the most stable for LiCoO2, whereas the formation of Li vacancies, O vacancies, and antisites between Li and Ni was thermodynamically unavoidable for LiNiO2. The introduction of both Co and Mn in LiNiO2 was effective in reducing the formation of point defects, but increasing the relative amount of Mn was undesirable because the antisite defect remained stable with Mn doping. The simulation showed good agreement with the experimental data and previous reports. Therefore, the method and the results of this study are expected to be useful for examining the synthesis, structure and related properties of layer-structured cathode materials. © 2015 Elsevier B.V.

Jung J.H.,Georgia Institute of Technology | Jung J.H.,Inha University | Lee M.,Georgia Institute of Technology | Hong J.-I.,Georgia Institute of Technology | And 5 more authors.
ACS Nano | Year: 2011

Perovskite ferroelectric nanowires have rarely been used for the conversion of tiny mechanical vibrations into electricity, in spite of their large piezoelectricity. Here we present a lead-free NaNbO 3 nanowire-based piezoelectric device as a high output and cost-effective flexible nanogenerator. The device consists of a NaNbO 3 nanowire-poly(dimethylsiloxane) (PDMS) polymer composite and Au/Cr-coated polymer films. High-quality NaNbO 3 nanowires can be grown by hydrothermal method at low temperature and can be poled by an electric field at room temperature. The NaNbO 3 nanowire-PDMS polymer composite device shows an output voltage of 3.2 V and output current of 72 nA (current density of 16 nA/cm 2) under a compressive strain of 0.23%. These results imply that NaNbO 3 nanowires should be quite useful for large-scale lead-free piezoelectric nanogenerator applications. © 2011 American Chemical Society.

Park J.-H.,Inha University
Journal of Asian Architecture and Building Engineering | Year: 2012

The design of a standard housing unit and the consequences of multiplying the unit in some larger assembly involve a certain degree of organizing principles. The most prevalent organizing principles in housing design are modular idea and symmetry. Both are of utmost importance as vehicles to guide all the components in the housing and to organize its spatial layouts. Modular ideas have been promoted in an attempt to minimize building costs as well as to execute efficient and accurate construction. Symmetrical operations function as the organizational mechanism for housing design. The employment of various symmetries in housing design is manifold and they apply to housing organization as a whole. They also apply to a standard unit with its typological variations and the grouping of multiple units in a larger assemblage. This paper analyzes a series of Rudolph M. Schindler's housing designs to illustrate the potential for the conscious application of the modular idea and symmetry in housing design as compositional methodologies.

Kweon M.,Inha University
Nuclear Physics A | Year: 2014

This article summarizes recent results on open heavy-flavour observables from selective experiments in relativistic nuclear collisions as presented during the Quark Matter 2014 conference. Commonalities and differences of their results are highlighted as a function of energy and relative to pp and pA collisions. © 2014 Elsevier B.V.

Sotto A.,Rey Juan Carlos University | Boromand A.,Catholic University of Leuven | Balta S.,Catholic University of Leuven | Balta S.,University of Galati | And 2 more authors.
Journal of Materials Chemistry | Year: 2011

Doping of nanofiltration membranes with TiO2 nanoparticles was studied in the ultralow concentration range, in the absence of photocatalysis. Blended polyethersulfone/TiO2 flat-sheet membranes were manufactured and investigated in terms of pure water flux, permeability, fouling resistance and solute rejection. The membranes were synthesized at four different polymer concentrations by the phase inversion method, using 1-methyl-2-pyrrolidone (NMP) and deionized water as solvent and coagulant, respectively. The influence of TiO2 addition was investigated in an unusually low concentration interval (0.035-0.375 wt%). The membrane morphology was studied by determining particle size distributions of TiO2 to explore the effect of nanoparticle aggregation. Furthermore, membranes were characterized by hydrophilicity (contact angle), morphology (SEM), porosity, mechanical strength (bursting pressure) and thermal analysis (TGA). Membrane fouling was studied with humic acids as model organic foulants. Overall, a remarkable improvement in the permeability was observed with the addition of ultralow amounts of nanoparticles to the polymer. The optimum permeability was found to be as low as 0.085 wt%, using a constant rejection of dyes as the boundary condition. It was shown that rejection of solutes is not negatively influenced by the increase in permeability. In addition, the resistance against membrane fouling was found to be above 12% for the TiO2 blended membranes. © 2011 The Royal Society of Chemistry.

Lee J.H.,Kyung Hee University | Rhee K.Y.,Kyung Hee University | Park S.J.,Inha University
International Journal of Hydrogen Energy | Year: 2010

Cryomilling was performed on multi-walled carbon nanotubes (MWCNTs) to investigate the effect of cyomilling on the structures and hydrogen storage characteristics of MWCNTs. Two milling speeds (300 and 700 rpm) and two milling times (2 and 6h) were applied in the cryomilling process. The results showed that the agglomeration of MWCNTs was significantly reduced, their lengths were shortened and the crystalline structure became amorphous at higher milling speed, whereas the milling time had no significant effect on the dispersibilities or structures of the MWCNTs. The hydrogen adsorption capacities of cryomilled MWCNTs at 700 rpm were improved by approximately 22% compared to that of unmilled MWCNTs due to the improvements in the specific surface area (17.4%) and pore volume (34.9%). Cryomilling is an effective method for increasing the surface area and pore volume, and macropores were transformed into mesopores, thereby enhancing the hydrogen storage capacity of the MWCNT surface. These results were confirmed by scanning and transmission electron microscopies, X-ray diffraction and Raman spectroscopic analysis. © 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.

The author created an innovative method of W-pushback and levator repositioning without having to make an incision to the nasal mucosa for submucous cleft palate repair.The W-shaped mucoperiosteal flap is outlined where the 2 peaks of W are the alveolar processes of both canine teeth and the midpoint of W is the anterior limit of the cleft notch of the hard palate. A short incision, medial to and behind the maxillary tuberosity and curved forward onto the palate and extended forward just medial to the alveolar process, is joined by a second incision from the apex of the cleft to the region of the canine tooth. The W-shaped mucoperiosteal flap is raised until the midline notch of the hard palate is exposed. The nasal mucosa and abnormally inserted levator veli palatini muscle to the posterior border of the hard palate bone are detached. By leaving the nasal mucosa intact, the detached levator veli palatini muscle is approximated at the midline and so the zona pellucida is obliterated. The cleft uvulas are cut in half and closed. The approximated W-flap is joined to the small anterior flap by 1 or more sutures (the W-pushback).Three patients were operated on with this technique without serious complications.The author believes that this method can make the levator sling and increase the length of the soft palate without making an incision to the nasal mucosa. Copyright © 2012 by Mutaz B. Habal, MD.

Jin F.-L.,Jilin Institute of Chemical Technology | Yop Rhee K.,Kyung Hee University | Park S.-J.,Inha University
Journal of Solid State Chemistry | Year: 2011

In this study, covalent functionalization of carbon nanotubes (CNTs) was accomplished by surface-initiated epoxide ring-opening polymerization. FT-IR spectra showed that polyether and epoxide group covalently attached to the sidewalls of CNTs. TGA results indicated that the polyether was successfully grown from the CNT surface, with the final products having a polymer weight percentage of ca. 1474 wt%. The O/C ratio of CNTs increased significantly from 5.1% to 29.8% after surface functionalization of CNTs. SEM and TEM images of functionalized CNTs exhibited that the tubes were enwrapped by polymer chains with thickness of several nanometers, forming coreshell structures with CNTs at the center. © 2011 Elsevier Inc. All rights reserved.

Park N.-W.,Inha University
International Journal of Remote Sensing | Year: 2010

This paper investigates the potential of accounting for temporal contextual information in order to improve the accuracy of land-cover classification in summer with Synthetic Aperture Radar (SAR) data. Bi-temporal multi-sensor datasets collected in the Nonsan area of Korea were used to illustrate this approach. Multi-sensor data, including Japanese Earth Resources Satellite (JERS)-1 Optical Sensor (OPS) data acquired in April, and three different SAR sensor datasets from European Resource Satellite (ERS)-2, JERS-1, and Radarsat-1 obtained in the following July, were used for supervised classification in July. By comparing the classification result in April with a training set in July, transition probabilities between land-cover classes in the April-July period were empirically estimated and regarded as the temporal contextual information. A tau model is applied as a main integration methodology to combine multiple SAR data and the temporal contextual information. From the evaluation of the classification results in terms of accuracy statistics, using multiple SAR sensor data showed an increase of about 29% in overall accuracy compared with the case of single SAR sensor data. The incorporation of temporal contextual information into scattering information greatly contributed to a significant improvement of about 25% in overall accuracy over multiple SAR sensor integration only, and showed the best discrimination capability. © 2010 Taylor & Francis.

Marroquin J.B.,Kyung Hee University | Rhee K.Y.,Kyung Hee University | Park S.J.,Inha University
Carbohydrate Polymers | Year: 2013

A novel, high-performance Fe3O4/MWNT/Chitosan nanocomposite has been prepared by a simple solution evaporation method. A significant synergistic effect of Fe3O4 and MWNT provided enhanced electrical conductivity, mechanical properties, and thermal stability on the nanocomposites. A 5% (wt) loading of Fe3O4/MWNT in the nanocomposite increased conductivity from 5.34 × 10-5 S/m to 1.49 × 10-2 S/m compared to 5% (wt) MWNT loadings. The Fe3O4/MWNT/Chitosan films also exhibited increases in tensile strength and modulus of 70% and 155%, respectively. The integral procedure decomposition temperature (IPDT) was enhanced from 501 °C to 568 °C. These effects resulted from a number of factors: generation of a greater number of conductive channels through interactions between MWNT and Fe 3O4 surfaces, a higher relative crystallinity, the antiplasticizing effects of Fe3O4, a restricted mobility and hindrance of depolymerization of the Chitosan chain segments, as well as uniform distribution, improved dispersion, and strong interfacial adhesion between the MWNT and Chitosan matrix. © 2012 Elsevier Ltd.

Jo T.,Inha University
Applied Soft Computing Journal | Year: 2013

This research proposes the three schemes of estimating and adding mid-terms to multivariate time series. In this research, the back propagation is adopted as the approach to multivariate time series prediction. It is traditionally designed for the task with the two models: separated model and combined model. In the proposed version of time series prediction systems, the mid-term estimator is added as the additional module to the traditional version. It is validated empirically that the three VTG (Virtual Term Generation) schemes are effective on using the back propagation for multivariate time series prediction on the four test data sets: three artificial one and a real test one. © 2012 Elsevier B.V. All rights reserved.

Jin S.-H.,Inha University
Computers and Education | Year: 2013

Despite the dynamic and interactive features of digital text, the visual design guidelines for digital text are similar to those for printed text. The purpose of this study was to develop visual design guidelines for improving learning from dynamic and interactive digital text and to validate them by controlled testing. Two structure design guidelines (for enhancing text structure comprehension) and two selective-attention design guidelines (for maintaining the learners' attention on the essential contents) were developed based on the psychological and instructional, technological foundations that can affect the visual design of digital text. In this study, a 2 × 2 factorial design with 141 university students was used to examine the effectiveness of the visual design guidelines. The university students had 20 min to study a piece of digital text with the structure design guidelines, selective-attention design guidelines, both, or no design guidelines applied. Both the structure and selective-attention design guidelines had a positive influence on text structure understanding, essential contents comprehension and usability of digital text. The suggested visual design guidelines were found to be useful for enhancing text comprehension. © 2012 Elsevier Ltd. All rights reserved.

Beom H.G.,Inha University
International Journal of Engineering Science | Year: 2013

Linear anisotropic thermoelastic in-plane problems are considered. A new formalism for general solutions of in-plane thermoelastic fields that satisfy the equilibrium equation and the steady state heat conduction equation is obtained in terms of analytic functions. The anisotropic thermoelastic formalism does not break down for a degenerate anisotropic thermoelastic solid with multiple characteristic roots, in contrast to the known solutions. An orthotropy rescaling technique is developed to determine the dependence of thermoelastic fields on the one dimensionless orthotropy parameter. The complete thermoelastic fields for the original problem can be evaluated from the solutions of the transformed problem by linear transformation with orthotropy rescaling. Thermal stresses in a simply connected anisotropic thermoelastic solid are investigated. Thermal stresses for the case of no mechanical loading anywhere on the boundary are expressed in terms of two dimensionless functions. The two dimensionless functions are shown to depend on only six dimensionless material parameters. © 2013 Elsevier Ltd. All rights reserved.

Kim Y.,Inha University
International Journal of Naval Architecture and Ocean Engineering | Year: 2013

Reliable strength assessment of the Liquefied Natural Gas (LNG) cargo containment system under the sloshing impact load is very difficult task due to the complexity of the physics involved in, both in terms of the hydrodynamics and structural mechanics. Out of all those complexities, the proper selection of the design sloshing load which is applied to the structural model of the LNG cargo containment system, is one of the most challenging one due to its inherent randomness as well as the statistical analysis which is tightly linked to the design sloshing load selection. In this study, the response based strength assessment procedure of LNG cargo containment system has been developed and proposed as an alternative design methodology. Sloshing pressure time history, measured from the model test, is decomposed into wavelet basis function targeting the minimization of the number of the basis function together with the maximization of the numerical efficiency. Then the response of the structure is obtained using the finite element method under each wavelet basis function of different scale. Finally, the response of the structure under entire sloshing impact time history is rapidly calculated by synthesizing the structural response under wavelet basis function. Through this analysis, more realistic response of the system under sloshing impact pressure can be obtained without missing the details of pressure time history such as rising pattern, oscillation due to air entrapment and decay pattern and so on. The strength assessment of the cargo containment system is then performed based on the statistical analysis of the stress peaks selected out of the obtained stress time history. © SNAK, 2013.

Beom H.G.,Inha University
International Journal of Engineering Science | Year: 2013

This paper investigates the generalized two-dimensional deformation of an anisotropic piezoelectric solid. A unified piezoelectric formalism for a general representation of elastic and electric fields in the anisotropic piezoelectric material is developed based on a transformed function method. This unified piezoelectric formalism is valid for degenerate anisotropic piezoelectric materials with multiple roots as well as for anisotropic piezoelectric materials with distinct roots. Closed-form solutions of elastic and electric fields for degenerate anisotropic piezoelectric materials are obtained by taking the limits in the piezoelectric formalism. Special attention is paid to a piezoelectric material with a plane of material property symmetry. Decoupled in-plane and anti-plane fields for this material are explicitly expressed. The usefulness of the unified piezoelectric formalism is discussed for the interface crack problem. © 2013 Elsevier Ltd. All rights reserved.

Lee H.,Dankook University | Jeonb T.-J.,Inha University
Physical Chemistry Chemical Physics | Year: 2015

Imidazolium-based ionic surfactants with hydrocarbon tails of different sizes were simulated with lipid bilayers at different salt concentrations. Starting with the random position of ionic surfactants outside the bilayer, surfactants with long tails mostly insert into the bilayer, while those with short tails show the insertion of fewer surfactant molecules, indicating the effect of the tail length. In particular, surfactants with a tail of two or four hydrocarbons insert and reversibly detach from the bilayer, while the inserted longer surfactants cannot be reversibly detached because of the strong hydrophobic interaction with lipid tails, in quantitative agreement with experiments. Longer surfactants insert more deeply and irreversibly into the bilayer and thus increase lateral diffusivities of the bilayer, indicating that longer surfactants more significantly disorder lipid bilayers, which also agrees with experiments regarding the effect of the tail length of ionic surfactants on membrane permeability and toxicity. Addition of NaCl ions weakens the electrostatic interactions between headgroups of surfactants and lipids, leading to the binding of fewer surfactants into the bilayer. In particular, our simulation findings indicate that insertion of ionic surfactants can be initiated by either the hydrophobic interaction between tails of surfactants and lipids or the electrostatic binding between imidazolium heads and lipid heads, and the strength of hydrophobic and electrostatic interactions depends on the tail length of surfactants. © the Owner Societies 2015.

Park C.-Y.,Korea Advanced Institute of Science and Technology | You C.-Y.,Inha University | Jeon K.-R.,Korea Advanced Institute of Science and Technology | Shin S.-C.,Korea Advanced Institute of Science and Technology | Shin S.-C.,Daegu Gyeongbuk Institute of Science and Technology
Applied Physics Letters | Year: 2012

We investigated the correlation between the ferromagnetism and electric resistivity of Mo-doped (3-10 at.) In 2O 3 films. We find that the saturation magnetization increases with the Mo concentration until it reaches its maximum at 7 at. Mo doping (7.1 emu/cm 3), after which it rapidly decreases upon higher doping concentration. Interestingly, the resistivity reveals opposite behavior with the Mo concentration, showing a minimum value at 7 at. Mo doping. According to the temperature-dependent resistivity and the Hall effect measurements, we find that the samples with higher magnetization show metallic behavior with higher electron concentration. Notably, the samples show a linear relationship between the carrier concentration and the degree of magnetization. We believe the ferromagnetism in Mo-doped In 2O 3 is ascribed to the indirect exchange interaction mediated by the charge carriers. © 2012 American Institute of Physics.

Kim K.J.,Samsung | Kwak K.S.,Inha University | Choi B.D.,Sungkyunkwan University
Journal of Communications and Networks | Year: 2013

Cognitive radio (CR) has emerged as one of effective methods to enhance the utilization of existing radio spectrum. Main principle of CR is that secondary users (SUs) are allowed to use the spectrum unused by primary users (PUs) without interfering PU's transmissions. In this paper, PUs operate on a slot-by-slot basis and SUs try to exploit the slots unused by PUs. We propose OSA protocols in the single channel and we propose an opportunistic spectrum access (OSA) protocols in the multi-channel cognitive radio networks with one control channel and several licensed channels where a slot is divided into contention phase and transmission phase. A slot is divided into reporting phase, contention phase and transmission phase. The reporting phase plays a role of finding idle channels unused by PUs and the contention phase plays a role of selecting a SU who will send packets in the data transmission phase. One SU is selected by carrier sense multiple access / collision avoidance (CSMA/CA) with request to send / clear to send (RTS/CTS) mechanism on control channel and the SU is allowed to occupy all remaining part of all idle channels during the current slot. For mathematical analysis, first we deal with the singlechannel case and we model the proposed OSA media access control (MAC) protocol by three-dimensional discrete time Markov chain (DTMC) whose one-step transition probability matrix has a special structure so as to apply the censored Markov chain method to obtain the steady state distribution. We obtain the throughput and the distribution of access delay. Next we deal with the multi-channel case and obtain the throughput and the distribution of access delay by using results of single-channel case. In numerical results, our mathematical analysis is verified by simulations and we give numerical results on throughput and access delay of the proposed MAC protocol. Finally, we find the maximum allowable number of SUs satisfying the requirements on throughput and access delay. © 2013 KICS.

Lee M.-K.,Inha University
IEEE Transactions on Information Forensics and Security | Year: 2014

The personal identification number (PIN) is a well-known authentication method used in various devices, such as ATMs, mobile devices, and electronic door locks. Unfortunately, the conventional PIN-entry method is vulnerable to shoulder-surfing attacks. Consequently, various shoulder-surfing resistant methods have been proposed. However, the security analyses used to justify these proposed methods are not based on rigorous quantitative analysis, but instead on the results of experiments involving a limited number of human attackers. In this paper, we propose new theoretical and experimental techniques for quantitative security analysis of PIN-entry methods. We first present new security notions and guidelines for secure PIN-entry methods by analyzing the existing methods under the new framework. On the basis of these guidelines, we develop a new PIN-entry method that effectively obviates human shoulder-surfing attacks by significantly increasing the amount of short-term memory required in an attack. © 2014 IEEE.

Ha S.H.,Hannam University | Koo Y.-M.,Inha University
Korean Journal of Chemical Engineering | Year: 2011

Ionic liquids (ILs) having unique properties such as no measurable vapor pressure, nonflammability and a wide temperature range of liquid phase have been recognized as potential green solvents. As a result, ILs have been extensively explored as reaction media for various biocatalytic reactions over a decade. Enzyme activities in ILs are generally comparable with or higher than those observed in conventional organic solvents. Furthermore, enhanced thermal and operational stabilities and regio- or enantioselectivities have been observed in many cases. Thus, ILs offer new possibilities for the application of solvent engineering to biocatalytic reactions. This review discusses the effect of physicochemical properties of ILs on biocatalysis with respect to enzyme activity, stability and selectivity by systematizing literature data on enzyme-catalyzed reaction in ILs. © 2011 Korean Institute of Chemical Engineers, Seoul, Korea.

Manna P.R.,Texas Tech University Health Sciences Center | Soh J.-W.,Inha University | Stocco D.M.,Texas Tech University Health Sciences Center
Endocrinology | Year: 2011

Protein kinase C (PKC) is a multigene family of serine/threonine kinases. PKC is involved in regulating adrenal and gonadal steroidogenesis; however, the functional relevance of the different PKC isoenzymes remains obscure. In this study, we demonstrate that MA-10 mouse Leydig tumor cells express several PKC isoforms to varying levels and that the activation of PKC signaling, by phorbol 12-myristate 13-acetate (PMA) elevated the expression and phosphorylation of PKCα,-δ,-ε, and-μ/protein kinase D (PKD). These responses coincided with the expression of the steroidogenic acute regulatory (StAR) protein and progesterone synthesis. Targeted silencing of PKCα, δ, and ε and PKD, using small interfering RNAs, resulted in deceases in basal and PMA-mediated StAR and steroid levels and demonstrated the importance of PKD in steroidogenesis. PKD was capable of controlling PMA and cAMP/PKA-mediated synergism involved in the steroidogenic response. Further studies pointed out that the regulatory events effected by PKD are associated with cAMP response element-binding protein (CREB)andc-Jun/c-Fos-mediated transcription of the StAR gene. Chromatin immunoprecipitation studies revealed that the activation of phosphorylated CREB, c-Jun, and c-Fos by PMA was correlated with in vivo protein-DNA interactions and the recruitment of CREB-binding protein, whereas knockdown of PKD suppressed the association of these factors with the StAR promoter. Ectopic expression of CREB-binding protein enhanced the trans-activation potential of CREB and c-Jun/c-Fos in StAR gene expression. Using EMSA, a-83/-67-bp region of the StAR promoter was shown to bind PKD-transfected MA-10 nuclear extract in a PMA-responsive manner, targeting CREB and c-Jun/c-Fos proteins. These findings provide evidence for the presence of multiple PKC isoforms and demonstrate the molecular events by which selective isozymes, especially PKD, influence PMA/PKC signaling involved in the regulation of the steroidogenic machinery in mouse Leydig cells. Copyright © 2010 The Endocrine Society. All rights reserved.

Anbu P.,Inha University
Preparative Biochemistry and Biotechnology | Year: 2014

Screening using spirit blue agar revealed that strain BK-L07 had the highest lipase activity. Furthermore, the isolated strain was identified as Pseudomonas sp. based on morphological, physiological, biochemical, and molecular analyses. The 16S rRNA gene sequence of strain BK-L07 shared a high similarity with that of Pseudomonas koreensis (99%). The nutritional conditions and physicochemical properties were influenced by P. koreensis BK-L07. The maximum lipase production was obtained in tryptic soy broth medium at pH 8.0 and a temperature of 25°C after 36 hr of incubation. In addition, the lipase activity was determined using different carbon sources and lipase inducers. The lipase production was greatest when 1% maltose was used as the carbon source and olive oil was used as the lipase inducer. The lipase production was significantly increased approximately threefold in the optimized medium when compared with the original medium. Further, the lipase was purified by ammonium sulfate precipitation and gel filtration chromatography with a purification yield of 10.8%. The molecular mass of lipase was 45 kDa. The optimum temperature and pH were 40°C and 8.0, respectively. The enzyme was stable up to 50°C and at pH from 7 to 9. In addition, the enzyme activity was stimulated by MgSO4 and completely inhibited by ethylenediamine tetraacetic acid (EDTA), indicating the metalloenzyme type. The lipase activity was toward medium to long chain length of fatty acids (C10 to C18). © 2014 Copyright Taylor and Francis Group, LLC.

Through micromagnetic simulations, it was found that the spin transfer torque (STT) switching current density is reduced with non-collinear polarizer layer magnetization. The dependence of the switching current density on the polarizer layer magnetization angle was investigated, and a typical magnetic tunneling junction structure with an exchange biased synthetic ferrimagnetic polarizer layers was considered. The easy axis of the polarizer layer was varied through controlling the exchange bias field direction in the ellipse cross-section nano-pillar structures. It was found that the switching current density was reduced by 39% when the exchange bias field was 10° from the long axis of the ellipse without the perpendicular STT. When the effect of the perpendicular STT was included, the switching current reductions were general for the non-collinear polarizer layer. © 2012 American Institute of Physics.

Korea plans to introduce an emissions trading scheme for the controlling greenhouse gas emissions in 2015. Using Shephard's (1970) output distance function, we first estimate the shadow price of CO2 for power generators in the Korean fossil-fueled electric generation industry. Then, by assuming that each power generator is required to reduce CO2 emissions by one ton, we compute the potential cost savings from internal trading among generators within the same plant and from external trading across plants at prevailing market prices. The results indicate that, on average, the generators paid $14.63 to abate one ton of CO2 emissions in 2007. Plants realized additional gains through external trading. In particular, cost savings from trades between different fuel-fired plants were substantial. © 2011 Elsevier Ltd.

Kim H.S.,Kyungsung University | Lee C.-G.,Inha University | Lee E.Y.,Kyung Hee University
Biotechnology and Bioprocess Engineering | Year: 2011

Alginate is a linear polysaccharide in which β- D-mannuronate (M) and its epimer, α-L-guluronate (G), are covalently (1-4)-linked in different sequences. Alginate is mainly used as a food additive to modify food texture due to its high viscosity and gelling property. Alginate lyase can degrade alginate by cleaving the glycosidic bond through a β-elimination reaction, generating oligomer with 4-deoxy-L-erythro-hex-4-enepyranosyluronate at the nonreducing end. Alginate oligosaccharides have been shown to stimulate the growth of human endothelial cells and the secretion of cytotoxic cytokines from human macrophage. Alginate can be converted into unsaturated monosaccharide by saccharification process using endolytic and exolytic alginate lyases, thus alginate lyases have potential as key biocatalyst for application of alginate as a renewable source for biochemicals and biofuels in near future. In this paper, structures and functions of various alginate lyases are reviewed. Prospects on future applications of alginate lyases are also discussed. © The Korean Society for Biotechnology and Bioengineering and Springer 2011.

Choi Y.,Inha University
Journal of biomedical materials research. Part B, Applied biomaterials | Year: 2012

Silk fibroin particles prepared by phase separation with polyethylene oxide were coated with calcium-deficient hydroxyapatite (CDHA) crystals under various pH conditions. For different pH values, the growth and the morphology of CDHA crystals on the surface of silk fibroin particles were investigated in detail by zeta potential analysis, scanning electron microscopy, transmission electron microscopy, and X-ray diffraction techniques. Negative charges formed by deprotonation of the functional groups on the surface of silk fibroin particles at high pH lead to an increase of binding affinity between the calcium ions of the CDHA crystals and the functional groups of the silk fibroin particles. Consequently, the generation of many CDHA crystals was promoted to deposit on the surface of silk fibroin particles at a high pH value. Copyright © 2012 Wiley Periodicals, Inc.

Cheong W.J.,Inha University
Journal of Separation Science | Year: 2014

It is surprising that there has been no devoted review article for frits and relevant studies so far despite the long history of packed columns and the use of frits in them. This review was activated for such a reason. Both separate frits and in situ permanent frits have been covered since the appearance of primitive frits. The in situ fritting methods such as the formation of organic monoliths, sol-gel technology, sintering, fritless techniques such as tapered tip and capillary restrictors, and miscellaneous fritting techniques including magnetically trapped frits and single particle frits are introduced and discussed. In addition, frit-related studies and patents are also introduced. Finally, some conclusive comments on the choice of fritting technique in different situations and future perspectives are given. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zhang N.,Jiangxi University of Finance and Economics | Choi Y.,Inha University
Renewable and Sustainable Energy Reviews | Year: 2014

Recently, a relatively new methodology named directional distance function (DDF) has been attracting positive attention in the field of energy and environmental (E&E) modeling. However, there is still no literature review on the application of DDF in E&E studies. This paper is intended to fill this gap. First, the most widely used DDF techniques and its extensions are briefly introduced. Second, this article attempts a classification of typical publications in this field. The main issues raised by the previous studies are discussed. Some guidelines for model selection and future directions are proposed for DDF related research in E&E studies. © 2014 Elsevier Ltd.

Zhang K.,Harbin Institute of Technology | Choi H.J.,Inha University
Materials | Year: 2014

This review article summarizes the preparation of polymer/carbon nanotube (CNT) nanocomposites and their applications as electrorheological (ER) fluids. These ER fluids exhibited a controllable electro-response under an applied electric field due to the presence of well-dispersed CNTs. The background, morphology, preparations, and characteristics of these materials are discussed, specifically focusing on the various approaches in the preparation of polymer/CNT nanocomposites, morphology, and their effects on the ER characteristics. © 2014 by the authors.

Of all the intracellular organelles, secretory granules contain by far the highest calcium concentration; secretory granules of typical neuroendocrine chromaffin cells contain ∼40 mM Ca2+ and occupy ∼20% cell volume, accounting for >60% of total cellular calcium. They also contain the majority of cellular inositol 1,4,5-trisphosphate receptors (IP3Rs) in addition to the presence of >2 mM of chromogranins A and B that function as high-capacity, low-affinity Ca2+ storage proteins. Chromogranins A and B also interact with the IP3Rs and activate the IP 3R/Ca2+ channels. In experiments with both neuroendocrine PC12 and nonneuroendocrine NIH3T3 cells, in which the number of secretory granules present was changed by either suppression or induction of secretory granule formation, secretory granules were demonstrated to account for >70% of the IP3-induced Ca2+ releases in the cytoplasm. Moreover, the IP3 sensitivity of secretory granule IP3R/Ca 2+ channels is at least ∼6- to 7-fold more sensitive than those of the endoplasmic reticulum, thus enabling secretory granules to release Ca2+ ahead of the endoplasmic reticulum. Further, there is a direct correlation between the number of secretory granules and the IP3 sensitivity of cytoplasmic IP3R/Ca2+ channels and the increased ratio of IP3-induced cytoplasmic Ca2+ release, highlighting the importance of secretory granules in the IP3-dependent Ca2+ signaling. Given that secretory granules are present in all secretory cells, these results presage critical roles of secretory granules in the control of cytoplasmic Ca2+ concentrations in other secretory cells. - Yoo, S. H. Secretory granules in inositol 1,4,5-trisphosphatedependent Ca2+ signaling in the cytoplasm of neuroendocrine cells. © FASEB.

Ryu H.-Y.,Inha University | Shim J.-I.,Hanyang University
IEEE Journal of Quantum Electronics | Year: 2010

Light extraction efficiency (LEE) in thin-film InGaN vertical light-emitting diode (LED) structures with photonic crystal patterns is studied using the three-dimensional finite-difference time-domain simulation. We systematically investigate the dependence of LEE on various structural parameters of photonic crystal vertical LEDs such as the thickness of the p-GaN and n-GaN layers, and air-hole depth and size. It is found that high LEE of >80% is obtainable from unencapsulated photonic crystal LEDs for a wide range of structural parameters. In particular, higher LEE is observed for the structures with relatively long-period photonic crystal patterns and possible mechanisms for the large enhancement of LEE are discussed. © 2009 IEEE.

Lee M.-J.,Incheon Christian Hospital | Kim C.-E.,Inha University
Journal of Korean Medical Science | Year: 2010

This report describes the efficacy of combined use of aripiprazole in the treatment of a patient with clozapine induced enuresis. Aripiprazole acts as a potential dopamine partial agonist and the dopamine blockade in the basal ganglia might be one of the causes of urinary incontinence and enuresis. We speculate that aripiprazole functioned as a D2 agonist in hypodopaminergic state of basal ganglia caused by clozapine and maintained dopamine level that would improve enuresis ultimately. © 2010 The Korean Academy of Medical Sciences.

Joo J.M.,Sungkyunkwan University | Lee S.,Inha University | Kwon O.C.,Sungkyunkwan University
International Journal of Hydrogen Energy | Year: 2012

The combustion stability limits and nitrogen oxide (NOx) emissions of burner-stabilized premixed flames of ammonia (NH 3)-substituted hydrogen (H2)-air mixtures at normal temperature and pressure are studied to evaluate the potential of partial NH3 substitution to improve the safety of H2 use. The effects of NH3 substitution, nitrogen (N2) coflow and mixture injection velocity on the stability limits and NOx emissions of NH3-H2-air flames are experimentally determined. Results show a reduction of stability limits with NH3 substitution and coflow, supporting the potential of NH3 as a carbon-free, green additive in H2-air flames and indicating a different tendency from that for no coflow condition. The NOx emission index is almost constant even with enhanced NH3 substitution, though the absolute value of NOx emissions increases in general. At fuel-rich conditions, the NOx emission index decreases with increasing mixture injection velocity and the existence of coflow. The thermal deNOx process in the post-flame region is involved in reducing NOx emissions for the fuel-rich flames. Copyright © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights.

Yadav M.,Kyung Hee University | Rhee K.Y.,Kyung Hee University | Park S.J.,Inha University
Carbohydrate Polymers | Year: 2014

In this work, graphene oxide/carboxymethylcellulose/alginate (GO/CMC/Alg) composite blends were prepared by a simple solution mixing-evaporation method. The resulting structure, thermal stability, and mechanical properties of the blends were investigated by wide-angle X-ray diffractometry, Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, thermogravimetric analysis, and mechanical testing. The obtained findings revealed that CMC, Alg, and graphene oxide were able to form a homogeneous mixture. When compared to a CMC/Alg blend, the incorporation of 1 wt% graphene oxide improved the tensile strength and Young's modulus by 40% and 1128%, respectively. In addition, the GO/CMC/Alg composite blend film showed a higher storage modulus than the CMC/Alg blend. © 2014 Elsevier Ltd.

Nam S.-I.,Korea Aerospace University | Kim H.-C.,Inha University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2011

We investigate the spin structure of the pion within the framework of the nonlocal chiral quark model from the instanton vacuum. We first evaluate the tensor form factors of the pion for the first and second moment (n=1,2) and compare it with the lattice data. Combining the tensor form factor of the pion with the electromagnetic one, we determine the impact-parameter dependent probability density of transversely polarized quarks inside the pion. It turns out that the present numerical results for the tensor form factor as well as those for the probability density are in good agreement with the lattice data. We also discuss the distortion of the spatial distribution of the quarks in the transverse plane inside the pion. © 2011 Elsevier B.V.

Zhang N.,Jiangxi University of Finance and Economics | Zhang N.,New York University | Choi Y.,Inha University
Energy Policy | Year: 2013

This paper aims to conduct a comparative study of the changes in CO2 emission performance of state-owned fossil fuel power plants between China and Korea. For this purpose, we combine the concept of the metafrontier Malmquist productivity index and the non-radial directional distance function to develop a new index called the non-radial metafrontier Malmquist CO2 emission performance index (NMMCPI). This new methodology allows for the incorporation of technological heterogeneities and slack variables into the previously introduced Malmquist CO2 emission performance index (MCPI). The NMMCPI can be derived by solving several non-radial data envelopment analysis (DEA) models. The NMMCPI can be decomposed into an efficiency change (EC) index, a best-practice gap change (BPC) index, and a technology gap change (TGC) index. By fixing the non-energy inputs, we measure the pure CO2 emission performance change. Based on the proposed indices, the comparative study between Chinese and Korean fossil fuel power industries is conducted for the 2005-2010 period. Empirical results indicate significant differences in terms of various decomposed CO2 emission performance changes between China and Korea. Korean power plants demonstrate improvements in innovation, while Chinese power plants demonstrate a higher ability for technological leadership. Some related policy implications are also proposed based on the empirical results. © 2013 Elsevier Ltd.

Zhang N.,Jiangxi University of Finance and Economics | Choi Y.,Inha University
Energy Economics | Year: 2013

This paper proposes the metafrontier non-radial Malmquist CO2 emission performance index (MNMCPI) for measuring dynamic changes in total-factor CO2 emission performance over time. The MNMCPI method allows for the incorporation of group heterogeneity and non-radial slack into the previously introduced Malmquist CO2 emission performance index (MCPI). We derive the MNMCPI by solving several non-radial data envelopment analysis (DEA) models. We decompose the MNMCPI into an efficiency change (EC) index, a best-practice gap change (BPC) index, and a technology gap change (TGC) index, and based on the proposed indices, we examine the dynamic changes in CO2 emission performance and its decomposition of fossil fuel power plants in China for the 2005-2010 period. The empirical results show a 0.38% increase in total-factor CO2 emission performance as a whole and a U-shaped MNMCPI curve for the sample period. Because companies owned by the central government lack innovation and technological leadership, the results suggest a missing link in the role of the central government in promoting CO2 emission performance. © 2013 Elsevier B.V.

The time series of the dynamic response of a slender marine structure was predicted in approximate sense using a truncated quadratic Volterra series. The wave-structure interaction system was identified using the NARX (Nonlinear Autoregressive with Exogenous Input) technique, and the network parameters were determined through supervised training using prepared datasets. The dataset used for network training was obtained by nonlinear finite element analysis of the slender marine structure under random ocean waves of white noise. The nonlinearities involved in the analysis were both large deformation of the structure under consideration and the quadratic term of the relative velocity between the water particle and structure in the Morison formula. The linear and quadratic frequency response functions of the given system were extracted using the multi-tone harmonic probing method and the time series of the response of the structure was predicted using the quadratic Volterra series. To check the applicability of the method, the response of a slender marine structure under a realistic ocean wave environment with a given significant wave height and modal period was predicted and compared with the nonlinear time domain simulation results. The predicted time series of the response of structure with quadratic Volterra series successfully captured the slowly varying response with reasonably good accuracy. This method can be used to predict the response of the slender offshore structure exposed to a Morison type load without relying on the computationally expensive time domain analysis, especially for screening purposes. © 2014 Elsevier Ltd.

Nguyen Q.H.,Ho Chi Minh University of Industry | Choi S.B.,Inha University
Smart Materials and Structures | Year: 2010

This paper presents an optimal design of a magnetorheological (MR) brake for a middle-sized passenger car which can replace a conventional hydraulic disc-type brake. In the optimization, the required braking torque, the temperature due to zero-field friction of MR fluid, the mass of the brake system and all significant geometric dimensions are considered. After describing the configuration, the braking torque of the proposed MR brake is derived on the basis of the field-dependent Bingham and Herschel-Bulkley rheological model of the MR fluid. The optimal design of the MR brake is then analyzed taking into account available space, mass, braking torque and steady heat generated by zero-field friction torque of the MR brake. The optimization procedure based on the finite element analysis integrated with an optimization tool is proposed to obtain optimal geometric dimensions of the MR brake. Based on the proposed procedure, optimal solutions of single and multiple disc-type MR brakes featuring different types of MR fluid are achieved. From the results, the most effective MR brake for the middle-sized passenger car is identified and some discussions on the performance improvement of the optimized MR brake are described. © 2010 IOP Publishing Ltd.

Choi W.J.,Yonsei University | Kim B.S.,Inha University | Lee J.W.,Yonsei University
American Journal of Sports Medicine | Year: 2012

Background: Several studies have addressed the issue of the feasibility of arthroscopic surgery in older patients, usually by choosing an arbitrary age limit.Hypothesis: Patient age is not associated with poor clinical outcome after arthroscopic surgery for osteochondral lesion of the talus (OLT), and other patient variables are the major determinants of clinical success/failure.Study Design: Cohort study; Level of evidence, 3.Methods: Between 2001 and 2008, 173 ankles underwent arthroscopic marrow stimulation treatment for OLT and were stratified into 6 age groups (<20, 20-29, 30-39, 40-49, 50-59, and ≥60 years). Bivariate and multivariate analyses were performed to determine the effect of age on clinical outcome.Results: There were no significant differences among the 6 age groups in the preoperative and postoperative visual analog scale (VAS) for pain or the American Orthopaedic Foot and Ankle Society (AOFAS) score. There was a significant increase in the duration of symptoms (P <.001) and a significant decrease in the incidence of trauma (P =.01) in the older group. Both the size of the osteochondral defect and the number of associated intra-articular lesions independently predicted a poor clinical outcome (P <.001).Conclusion: In contrast to some of the previous studies on this topic, we found that increased age was not an independent risk factor for poor clinical outcome after arthroscopic treatment for OLT. We did find that older patients were less likely to have a history of trauma and had a longer duration of symptoms, had smaller osteochondral defects, and had more associated intra-articular lesions. © 2012 American Orthopaedic Society for Sports Medicine.

Jiang W.,Jilin Institute of Chemical Technology | Jin F.-L.,Jilin Institute of Chemical Technology | Park S.-J.,Inha University
Journal of Industrial and Engineering Chemistry | Year: 2012

This study examined the thermo-mechanical behavior of epoxy resins/nano-Al 2O 3 composites including the curing behavior, thermal stability, dynamic mechanical properties and thermal mechanical properties. The DSC curve peak temperature of the composites was decreased by the addition of nano-Al 2O 3. The thermal stability of the composites was similar to that of the neat epoxy resins. Dynamic mechanical analysis (DMA) indicated the glass transition temperature of the composites to be approximately 11°C higher than that of the neat epoxy resins. The coefficient of thermal expansion (CTE) of the composites decreased with increasing nano-Al 2O 3 content. © 2011 The Korean Society of Industrial and Engineering Chemistry.

The author theoretically investigates the effects of internal polarization fields on the efficiency of InGaN/GaN multiple-quantum-well (MQW) blue light-emitting diodes (LEDs) based on numerical simulations. Internal quantum efficiency (IQE), current leakage, and carrier distributions are calculated with varying the strength of polarization fields to study the role of the polarization fields on the efficiency characteristics. Simulation results show that, as the strength of the polarization fields increases, electron current leakage from active layers to the p-GaN layer increases and hole concentration distribution at MQWs becomes more inhomogeneous. It is found that these two effects by the internal polarization fields lead to significant decrease in the IQE of InGaN blue LEDs. © 2012 The Japan Society of Applied Physics.

You C.-Y.,Inha University
Current Applied Physics | Year: 2010

Critical current density of composite free layer (CFL) in magnetic tunneling junction is investigated. CFL consists of two exchange coupled ferromagnetic layers, where the coupling is parallel or anti-parallel. Instability condition of the CFL under the spin transfer torque, which is related with critical current density, is obtained by analytic spin wave excitation model and confirmed by macro-spin Landau-Lifshitz-Gilbert equation. The critical current densities for the coupled two identical layers are investigated with various coupling strengths, and spin transfer torque efficiencies. © 2009 Elsevier B.V. All rights reserved.

Gu J.Y.,California State University, Long Beach | Kusnadi J.,California State University, Long Beach | You C.-Y.,Inha University
Physical Review B - Condensed Matter and Materials Physics | Year: 2010

We investigate the proximity effect in a superconductor/ferromagnet (S/F) hybrid system with a noncollinear magnetic configuration. A new structure of an S/exchange-spring (ES) magnet is fabricated, where an ES magnet is employed as an F layer since the magnetization configuration is varied from a collinear state to a noncollinear state by a rotating external magnetic field in a well controllable way. We found that the resistance decreases and the superconducting transition temperature increases, as noncollinearity is introduced starting from a collinear state. We interpret that our experimental observation is due to the contribution of the odd-triplet superconducting condensate that survived in a noncollinear magnetization configuration in the ES magnet. © 2010 The American Physical Society.

Ham B.S.,Inha University
Journal of the Optical Society of America B: Optical Physics | Year: 2011

Optical locking applied to rephased atoms in photon echoes is analyzed for on-demand photon storage time extension, where the storage time extension is confined by the inverse of spin inhomogeneous broadening. Both optical locking and photon storage mechanisms in atomic frequency comb echoes are discussed and compared with those in two-pulse photon echo-based phase-locked echoes and three-pulse photon echoes. © 2011 Optical Society of America.

Jo T.,Inha University
Proceedings - 2013 IEEE International Conference on Granular Computing, GrC 2013 | Year: 2013

This research is concerned with applying the table based approach to text categorization in the bio-medical domain. The popularity and interests in the bio-medical domain are increasing recently with respect to the text processing. In this research, we encode texts in the domain into tables, define the similarity measure between tables representing the texts, and apply it to categorizations of the bio-medical texts. We may expect better performance and stability of the proposed approach as well as in other domains. Thus, we will use the collection of medical documents, called Oshumed, as the test data for evaluating the proposed approach. © 2013 IEEE.

Jung M.H.,Sogang University | Park S.,Korea Basic Science Institute | You C.-Y.,Inha University | Yuasa S.,Japan National Institute of Advanced Industrial Science and Technology
Physical Review B - Condensed Matter and Materials Physics | Year: 2010

We investigate the bias dependences of in-plane and out-of-plane spin-transfer torque by employing magnetic noise measurement in symmetric MgO-based magnetic tunneling junction devices. The measured power spectra densities of magnetic noise are successfully analyzed by the fluctuation-dissipation theorem with an imaginary part of transverse susceptibility including spin-transfer torque contributions. We find that the in-plane component has a linear dependence of the bias voltage, while the out-of-plane component has a quadratic dependence. These results are well consistent with the noise amplitude analysis, neglecting the Joule heating effect with small bias voltage. © 2010 The American Physical Society.

Kang S.M.,KAIST | Park S.,Inha University | Kim D.,KAIST | Park S.Y.,Korea University | And 2 more authors.
Advanced Functional Materials | Year: 2011

This study presents a method of simultaneous reduction and surface functionalization of graphene oxide by a one-step poly(norepinephrine) functionalization. The pH-induced aqueous functionalization of graphene oxide by poly(norepinephrine), a catecholamine polymer inspired by the robust adhesion of marine mussels, chemically reduced and functionalized graphene oxide. Moreover, the polymerized norepinephrine (pNor) layer provided multifunctionality on the reduced graphene oxide that includes surface-initiated polymerization and spontaneous metallic nanoparticle formation. This facile surface modification strategy can be a useful platform for graphene-based nano-composites. Simultaneous reduction and surface functionalization of graphene oxide were achieved via a simple one-step procedure under mild conditions. An aqueous mixture of graphene oxide and a norepinephrine, a molecule inspired by the chemical composition of mussel adhesive proteins, resulted in a robust modification of graphene oxide surfaces. The poly(norepinephrine) modification exhibited simultaneous reduction of graphene oxide and became a platform of surface-initiated polymerization and metallic nanoparticle formation. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Oh C.H.,Guro Teun Teun Hospital | Yoon S.H.,Inha University
Keio Journal of Medicine | Year: 2013

Cervical arthroplasty was developed in an attempt to maintain cervical motion and potentially to avoid or minimize adjacent-segment degeneration. If cervical arthroplasty is successful, the long-term results of surgery for cervical disc disease should improve. However, problems associated with cervical arthroplasty have been reported: these include kyphosis, heterotopic ossification-induced motion limitation, no motion preservation even at the index level, and a higher revision rate in a limited number of cases compared with anterior cervical discectomy and fusion (ACDF). In addition, for degenerative cervical disc disorders, the risk of developing adjacent segment degeneration more than 2 years after surgery is reportedly similar for ACDF and cervical arthroplasty. Cervical disc arthroplasty is an emerging motion-sparing technology and is currently undergoing evaluation in many countries as an alternative to arthrodesis for the treatment of cervical radiculopathy and myelopathy. The decision whether to use arthrodesis or arthroplasty is a difficult one. The achievement of good prosthetic performance demands exacting implantation techniques to ensure correct placement. This fact underlines the increasing importance of special instrumentation and surgical skills that involve an understanding of prosthetic lubrication, wear, and biologic effects and familiarity with currently available information regarding kinematics, basic science, testing, and early clinical results. Fortunately, a number of devices are at the late preclinical study stage or at the early clinical trial stage, and results in many cases are promising. In the near future, it is likely that new designs will be produced to replace spinal discs totally or partially in a pathologic entity-specific manner. © 2013 by The Keio Journal of Medicine.

Lee D.,University of Michigan | Bolton O.,University of Michigan | Kim B.C.,University of Michigan | Youk J.H.,Inha University | And 2 more authors.
Journal of the American Chemical Society | Year: 2013

Developing metal-free organic phosphorescent materials is promising but challenging because achieving emissive triplet relaxation that outcompetes the vibrational loss of triplets, a key process to achieving phosphorescence, is difficult without heavy metal atoms. While recent studies reveal that bright room temperature phosphorescence can be realized in purely organic crystalline materials through directed halogen bonding, these organic phosphors still have limitations to practical applications due to the stringent requirement of high quality crystal formation. Here we report bright room temperature phosphorescence by embedding a purely organic phosphor into an amorphous glassy polymer matrix. Our study implies that the reduced beta (β)-relaxation of isotactic PMMA most efficiently suppresses vibrational triplet decay and allows the embedded organic phosphors to achieve a bright 7.5% phosphorescence quantum yield. We also demonstrate a microfluidic device integrated with a novel temperature sensor based on the metal-free purely organic phosphors in the temperature-sensitive polymer matrix. This unique system has many advantages: (i) simple device structures without feeding additional temperature sensing agents, (ii) bright phosphorescence emission, (iii) a reversible thermal response, and (iv) tunable temperature sensing ranges by using different polymers. © 2013 American Chemical Society.

Ki S.H.,Inha University
Annals of Plastic Surgery | Year: 2016

The lateral arm free flap offers many advantages in reconstruction of soft tissue defect and reconstruction of extremities. However, this free flap is associated with sensory loss at the posterior forearm due to injury of the posterior antebrachial cutaneous nerve (PABCN). The PABCN-sparing lateral arm free flaps were performed in 19 patients with various soft tissue defects of the extremity, and the outcomes of free flap reconstructions using this modification are evaluated. All flaps survived without partial necrosis. Three patients experienced transient sensory loss in the posterior area of the forearm after flap harvest. In this study, lateral arm free flaps can be elevated without necessarily sacrificing the PABCN. This nerve-sparing modification decreases the donor-site morbidity of lateral arm free flaps and further increases the overall usefulness of this flap in soft tissue reconstructions of the extremities. © 2016 Wolters Kluwer Health, Inc.

The majority of secretory cell calcium is stored in secretory granules that serve as the major IP 3-dependent intracellular Ca 2+ store. Even in unicellular phytoplankton secretory granules are responsible for the IP 3-induced Ca 2+ release that triggers exocytosis. The number of secretory granules in the cell is directly related not only to the magnitude of IP 3-induced Ca 2+ release, which accounts for the majority of the IP 3-induced cytoplasmic Ca 2+ release in neuroendocrine cells, but also to the IP 3 sensitivity of the cytoplasmic IP 3 receptor (IP 3R)/Ca 2+ channels. Moreover, secretory granules contain the highest IP 3R concentrations and the largest amounts of IP 3Rs in any subcellular organelles in neuroendocrine cells. Secretory granules from phytoplankton to mammals contain large amounts of polyanionic molecules, chromogranins being the major molecules in mammals, in addition to acidic intragranular pH and high Ca 2+ concentrations. The polyanionic molecules undergo pH- and Ca 2+-dependent conformational changes that serve as a molecular basis for condensation-decondensation phase transitions of the intragranular matrix. Likewise, chromogranins undergo pH- and Ca 2+-dependent conformational changes with increased exposure of the structure and increased interactions with Ca 2+ and other granule components at acidic pH. The unique physico-chemical properties of polyanionic molecules appear to be at the center of biogenesis, and physiological functions of secretory granules in living organisms from primitive to advanced species. © 2010 Elsevier Ltd.

Jin F.-L.,Jilin Institute of Chemical Technology | Park S.-J.,Inha University
Polymer Degradation and Stability | Year: 2012

Epoxy resin/filler hybrid composites were prepared by the melt blending of diglycidylether of bisphenol- A (DGEBA), as the epoxy resin, with nano-Al 2O3 or nano-SiC particles, as the nanoscaled fillers. The thermal properties, such as the curing behavior, thermal stability, dynamic mechanical properties, and thermal mechanical properties of the DGEBA/nano-Al2O3 and DGEBA/nano-SiC composites were examined using a range of techniques. As a result, the DSC curve peak temperature of both composites decreased with increasing filler content. The integral procedure decomposition temperature increased from 630 °C to 853 °C for DGEBA/nano-Al2O3 composite and 858 °C for DGEBA/nano-SiC composite. The char yield at 800 °C increased from 14.3% to 26.2-26.6% for both composites. Both composites had a 10 °C higher glass transition temperature than the neat epoxy resin. The coefficient of thermal expansion of both composites at the glassy and rubbery regions decreased with increasing filler content. © 2012 Elsevier Ltd. All rights reserved.

Kim K.J.,Inha University | Tsiftsis T.A.,Technological Educational Institute of Lamia | Poor H.V.,Princeton University
IEEE Transactions on Wireless Communications | Year: 2011

To address the issues of high peak-to-average power ratio and high power backing-off in orthogonal frequency-division multiplexing (OFDM) relaying systems, a cyclic prefixed single-carrier (CP-SC) relaying system employing best terminal selection (BTS) is considered in this paper. Under a system power constraint, the problem of joint optimal power allocation to the source and relay is investigated. For a two-hop amplify-and-forward (AF) relaying protocol, the optimal power allocation is first obtained by maximizing the achievable spectral efficiency. After applying the obtained optimal power allocations to the source and relay, a destination terminal that has the best effective end-to-end signal-to-noise ratio is selected. With the help of the statistical properties of circulant channel matrices in the relay links, closed-form bounds for the maximum achievable spectral efficiency, outage probability, and average symbol error rate (ASER) are derived. Further, an asymptotic analysis of the outage probability and ASER is conducted and it is shown that both the number of terminals in the system and the number of channel taps being supported by the CP length play key roles in determining the overall diversity gain. Monte Carlo simulation results verify the derived closed-form analytical expressions. © 2011 IEEE.

The purpose of this study was to determine the pharmacogenetic effects of complement factor H (CFH) Y402H, LOC387715 and high-temperature requirement factor A1 (HTRA1) genotypes on the treatment of exudative age-related macular degeneration (AMD) by intravitreal bevacizumab injection in a Korean population. Seventy-five patients diagnosed with exudative AMD were treated with intravitreal bevacizumab (2.5 mg) monotherapy. All patients received three initial intravitreal bevacizumab injections every four weeks and were then treated "as needed" based on clinical findings, optical coherence tomography and fluorescein angiography during the 12 month follow-up period after the third injection. The difference in visual acuity improvement among the three genotypes of LOC387715 were statistically significant at six months post-treatment (logarithm of the minimum angle of resolution; TT, 0.346; GT, 0.264; GG, 0.188; p = 0.037). Among the LOC387715 genotypes, the number of additional injections was lower in patients who had the risk T allele (GG, 2.143; GT, 2.000; TT, 1.575; p = 0.064). There was no significant difference between visual acuity and central macular thickness change in the CFH Y402H polymorphism group during the 12 month follow-up period. However, the TC group of CFH Y402H required more additional bevacizumab injections than the TT group (TT, 1.517; TC, 3.363; p = 0.020). This study demonstrated that different LOC387715/HTRA1 genotypes resulted in different bevacizumab treatment responses on exudative AMD. Patients with the risk allele had an improved treatment response and less need for additional injections. However, patients with the CFH Y402H risk allele needed more additional injections of bevacizumab in order to improve visual acuity. This study illustrates how pharmacogenetic factors may help determine treatment modality and dosing. This could ultimately provide basic data for 'personalized medicine' in AMD.

Choi M.-B.,Chonnam National University | Jeon S.-Y.,Chonnam National University | Lee J.-S.,Chonnam National University | Hwang H.-J.,Inha University | Song S.-J.,Chonnam National University
Journal of Power Sources | Year: 2010

The transport properties of layered perovskite GdBaCo2O5+δ (GBCO), which has recently been proposed as a cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs), are investigated as a function of oxygen partial pressure (OPP) over the oxygen partial pressure range of 10-4 ≤ pO2 (atm) ≤ 0.21 at 1073 ≤ T (K) ≤ 1323. The increase in total conductivity with increasing temperature below the low-temperature, order-disorder transition indicates a semiconductor-type behaviour with an activation energy of 0.42 eV. When OPP is increased to air pressure at a fixed temperature, the total conductivity increases with an apparent slope (∂log σ/∂log pO2) of 1/10 to 1/22. The maximum oxygen ion conductivity, as extracted from the oxygen permeation measurements, is around 0.01 S cm-1 under the nitrogen condition, which strongly supports the potential for cathode application. The chemical diffusion coefficient (over(D, ̃)) and surface exchange coefficient (κ) are also calculated from the d.c. conductivity relaxation measurement and the values are best fitted by the following two equations:over(D, ̃) (c m2 s- 1) = 1.88 × 10- 2 exp fenced(- frac(0.77 eV, k T)), κ (cm s- 1) = 1.37 × 100 exp fenced(- frac(0.86 eV, k T)). © 2009 Elsevier B.V. All rights reserved.

Ashrafuzzaman K.,Chittagong University | Kwak K.S.,Inha University
IEEE Communications Letters | Year: 2011

Employing relatively simple constructs, this letter presents an analytical model for the slotted CSMA/CA algorithm adopted in the contention access period of the beacon-enabled mode MAC in IEEE 802.15.4. The analysis is validated against simulation vis-a-vis another related model. © 2011 IEEE.

Lee L.,Pusan National University | Park S.-J.,Inha University | Kim S.,Pusan National University
Solid State Ionics | Year: 2013

In the present study, poly(ethylene oxide) (PEO) and poly(vinylidene fluoride) (PVDF) blend based composite polymer electrolytes (CPEs) had been prepared by using a different content of nano-sized BaTiO3 filler, in order to examine the filler addition effect on the structural modification and electrochemical properties. The crystallinity and thermal stability of the CPEs was evaluated using differential scanning calorimeter (DSC), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The electrochemical properties of CPEs were measured by the AC impedance method and cyclic voltammetry (CV). As a result, Both DSC and XRD results indicated that the CPE showed reduced crystallinity after the introduction of BaTiO3 filler. From the ionic conductivity results, the CPE containing BaTiO3 filler 15 wt.% showed the highest ionic conductivity (1.2 × 10- 4 S/cm) with a wide electrochemical stability window and an excellent thermal stability at room temperature. This indicated that electrochemical characteristics are dependent on the reduced crystallinity by the addition of nano-sized BaTiO 3 filler content. © 2013 Elsevier B.V.

Park N.-W.,Inha University
Environmental Earth Sciences | Year: 2011

GIS-based spatial data integration tasks for predictive geological applications, such as landslide susceptibility analysis, have been regarded as one of the primary geological application issues of GIS. An efficient framework for proper representation and integration is required for this kind of application. This paper presents a data integration framework based on the Dempster-Shafer theory of evidence for landslide susceptibility mapping with multiple geospatial data. A data-driven information representation approach based on spatial association between known landslide occurrences and input geospatial data layers is used to assign mass functions. After defining mass functions for multiple geospatial data layers, Dempster's rule of combination is applied to obtain a series of combined mass functions. Landslide susceptibility mapping using multiple geospatial data sets from Jangheung in Korea was conducted to illustrate the application of this methodology. The results of the case study indicated that the proposed methodology efficiently represented and integrated multiple data sets and showed better prediction capability than that of a traditional logistic regression model. © 2010 Springer-Verlag.

The purpose of the present investigation was to study the effects of ionizing radiation on endothelial cells derived from diverse normal tissues. We first compared the effects of radiation on clonogenic survival and tube formation of endothelial cells, and then investigated the molecular signaling pathways involved in endothelial cell survival and angiogenesis. Among the different endothelial cells studied, human hepatic sinusoidal endothelial cells (HHSECs) were the most radio-resistant and human dermal microvascular endothelial cells were the most radio-sensitive. The radio-resistance of HHSECs was related to adenosine monophosphate-activated protein kinase and p38 mitogen-activated protein kinase-mediated expression of MMP-2 and VEGFR-2, whereas the increased radio-sensitivity of HDMECs was related to extracellular signal-regulated kinase-mediated generation of angiostatin. These observations demonstrate that there are distinct differences in the radiation responses of normal endothelial cells obtained from diverse organs, which may provide important clues for protection of normal tissue from radiation exposure.

Joo H.-J.,Inha University | Kwak H.-Y.,Korea Institute of Energy Research
Applied Thermal Engineering | Year: 2013

In this study we have carried out a performance evaluation on a recently developed multi-effect distiller with a 3 m3/day capacity and Shell & Tube type heat exchanger, which has been optimized for solar thermal desalination systems in order to increase mechanical efficiency and economical efficiency. Also, the effective heat transfer of Shell & Tube heat exchanger was used in Cu (90%) - NI (10%) corrugated tube. The parameters relating to the performance of multi effect distillation are known as hot water flow rate. The experimental conditions for each parameters were 18 C for seawater inlet temperature, 6 m3/h seawater inlet volume flow rate, 75 C for hot water inlet temperature, 2.4, 3.6, and 4.8 m3/h for hot water inlet volume flow rate, respectively. The results are as follows, development for multi effect distillation was required about 40 kW heat and 35 kW cooling source to produce 3 m3/day of fresh water. And, performance ratio of development multi effect distillation was about 2.0191. © 2013 Elsevier Ltd. All rights reserved.

In Korea, price subsidies for industrial power are provided by the government in order to enhance industrial competitiveness and curb inflation. However, this repeatedly causes electricity shortages in the peak summer and winter seasons because of over-consumption. Forcing a decline in the demand for electricity by raising power rates would thus help prevent a national blackout, lowering dependence on foreign energy and reducing CO2 emissions cost-effectively. This paper simulates the effects of a rise in power rate on demand for electricity and output price by estimating a restricted cost function, in which the quantity of raw materials is set to its cost-minimizing level, jointly with an inverse supply relation for the top three electricity-intensive manufacturing sectors. The empirical results indicate that a 10% increase in electricity rate would result in 8.0-10.1% less demand across all three manufacturing sectors, ceteris paribus. The impact on output price is of little statistical significance in the basic metals sector, while output price on average falls by 0.16% in the TV and communication equipment sector. © 2013 Elsevier Ltd.

Lee J.,Yonsei University | Kim J.,Yonsei University | Kwon H.-D.,Inha University
Journal of Theoretical Biology | Year: 2013

This study considers an optimal intervention strategy for influenza outbreaks. Variations in the SEIAR model are considered to include seasonal forcing and age structure, and control strategies include vaccination, antiviral treatment, and social distancing such as school closures. We formulate an optimal control problem by minimizing the incidence of influenza outbreaks while considering intervention costs. We examine the effects of delays in vaccine production, seasonal forcing, and age-dependent transmission rates on the optimal control and suggest some optimal strategies through numerical simulations. © 2012 Elsevier Ltd.

Min S.-Y.,Pohang University of Science and Technology | Kim T.-S.,Pohang University of Science and Technology | Kim B.J.,Sungkyunkwan University | Cho H.,Pohang University of Science and Technology | And 4 more authors.
Nature Communications | Year: 2013

Controlled alignment and patterning of individual semiconducting nanowires at a desired position in a large area is a key requirement for electronic device applications. High-speed, large-area printing of highly aligned individual nanowires that allows control of the exact numbers of wires, and their orientations and dimensions is a significant challenge for practical electronics applications. Here we use a high-speed electrohydrodynamic organic nanowire printer to print large-area organic semiconducting nanowire arrays directly on device substrates in a precisely, individually controlled manner; this method also enables sophisticated large-area nanowire lithography for nano-electronics. We achieve a maximum field-effect mobility up to 9.7 cm2 V -1 s-1 with extremely low contact resistance (<5.53 Ω cm), even in nano-channel transistors based on single-stranded semiconducting nanowires. We also demonstrate complementary inverter circuit arrays comprising well-aligned p-type and n-type organic semiconducting nanowires. Extremely fast nanolithography using printed semiconducting nanowire arrays provide a simple, reliable method of fabricating large-area and flexible nano-electronics. © 2013 Macmillan Publishers Limited. All rights reserved.

Choi B.G.,Korea Advanced Institute of Science and Technology | Huh Y.S.,Inha University | Hong W.H.,Korea Advanced Institute of Science and Technology | Erickson D.,Cornell University | Park H.S.,Kyung Hee University
Nanoscale | Year: 2013

Hierarchical structures of hybrid materials with the controlled compositions have been shown to offer a breakthrough for energy storage and conversion. Here, we report the integrative assembly of chemically modified graphene (CMG) building blocks into hierarchical complex structures with the hybrid composition for high performance flexible pseudocapacitors. The formation mechanism of hierarchical CMG/Nafion/RuO2 (CMGNR) microspheres, which is triggered by the cooperative interplay during the in situ synthesis of RuO2 nanoparticles (NPs), was extensively investigated. In particular, the hierarchical CMGNR microspheres consisting of the aggregates of CMG/Nafion (CMGN) nanosheets and RuO2 NPs provided large surface area and facile ion accessibility to storage sites, while the interconnected nanosheets offered continuous electron pathways and mechanical integrity. The synergistic effect of CMGNR hybrids on the supercapacitor (SC) performance was derived from the hybrid composition of pseudocapacitive RuO2 NPs with the conductive CMGNs as well as from structural features. Consequently, the CMGNR-SCs showed a specific capacitance as high as 160 F g-1, three-fold higher than that of conventional graphene SCs, and a capacitance retention of >95% of the maximum value even after severe bending and 1000 charge-discharge tests due to the structural and compositional features. © 2013 The Royal Society of Chemistry.

Oh P.-J.,Sahmyook University | Kim S.H.,Inha University
Oncology Nursing Forum | Year: 2014

Purpose/Objectives: To evaluate the effects of a spiritual intervention in patients with cancer. Data Sources: Databases searched included both international electronic databases (MEDLINE® via PubMed, Cochrane Library CENTRAL, EMBASE, and CINAHL®) as well as Korean electronic databases (KMBASE, KOREAMED, RISS, KISS, and NANET) through December 2013. Data Synthesis: A meta-analysis was conducted of 15 studies involving 14 controlled trials (7 randomized and 7 nonrandomized) with 889 patients with cancer. Spiritual interventions were compared with a usual care control group or other psychosocial interventions. The weighted average effect size across studies was -0.48 (p = 0.006, I2 = 65%) for spiritual well-being, -0.58 (p = 0.02, I2 = 70%) for meaning of life, -0.87 (p = 0.02, I2 = 87%) for anxiety, and -0.62 (p = 0.001, I2 = 73%) for depression. Conclusions: The findings showed that spiritual interventions had significant but moderate effects on spiritual well-being, meaning of life, and depression. However, the evidence remains weak because of the mixed study design and substantial heterogeneity. Implications for Nursing: Oncology nurses increasingly recognize the significance of the spiritual domain of care. The current study indicates that facilitating spiritual awareness and needs may be a worthwhile nursing intervention for patients with cancer. © 2014 by the Oncology Nursing Society.

A prerequisite for the successful clinical application of gene therapy in erectile dysfunction (ED) is the availability of safe and efficient gene delivery systems. The aim of this study was to examine the effectiveness of guanidinylated bioreducible polymer (GBP) polyplexes for gene delivery systems, which take advantage of the biodegradability of reducible disulfide bonds and the cell-penetrating ability of guanidine groups. For in vitro transfection experiments, we used mouse cavernous endothelial cells and A7r5 rat vascular smooth muscle cells. For in vivo experiments, we used a mouse model of hypercholesterolaemic ED in which 2-month-old male C57BL/6 mice were fed a diet containing 4% cholesterol and 1% cholic acid for 3 months. Animals or cells were treated with pCMV-Luc, poly(ethyleneimine) (PEI)25k/pCMV-Luc polyplex (weight ratio: 1) and GBP/pCMV-Luc polyplexes (weight ratio: 20, 40, 60 and 80). Gene expression was evaluated by luciferase assay, and the gene expression area was evaluated by immunohistochemistry. GBP had greater transfection efficiency as the weight ratio increased. GBP had sevenfold higher gene delivery efficiency in A7r5 cells at a weight ratio of 80 than did PEI25k. Moreover, the gene expression was more profoundly induced by GBP/pCMV-Luc than by pCMV-Luc in both the corpus cavernosum tissue of hypercholesterolaemic mice and in mouse cavernous endothelial cells, although the expression levels induced by the GBP gene delivery system were lower than those induced by the PEI25k gene delivery system. GBP revealed no considerable cytotoxicity to A7r5 cells and mouse cavernous endothelial cells (relative cell viability: 95 and 88% respectively), whereas PEI25k resulted in high cytotoxicity. Interestingly, immunofluorescent double staining revealed that luciferase expression induced by the GBP polyplex mainly overlapped with cavernous endothelial cells, but rarely with smooth muscle cells. The GBP-based non-viral gene expression system may be useful for the development of gene therapy in vasculogenic ED. © 2013 American Society of Andrology and European Academy of Andrology.

Yadav M.,Kyung Hee University | Rhee K.Y.,Kyung Hee University | Jung I.H.,Kyung Hee University | Park S.J.,Inha University
Cellulose | Year: 2013

A previously unreported nanocomposite (CMC/GO) high-performance film was prepared by a simple solution mixing-evaporation method. The structure, thermal stability, and mechanical properties of the composite films were investigated by wide-angle X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, thermogravimetry analysis, and mechanical testing. The results obtained from these different studies revealed that CMC and graphene oxide were able to form a homogeneous mixture. Compared with pure CMC, the tensile strength and Young's modulus of the graphene-based materials were improved significantly upon incorporation of 1 wt% graphene oxide by 67 ± 6 % and 148 ± 5 %, respectively. In addition, the DMA composite films also showed a high storage modulus up to 250 °C. © 2012 Springer Science+Business Media Dordrecht.

Ha C.-W.,Sungkyunkwan University | Noh M.J.,TissueGene Inc. | Choi K.B.,Kolon Life Science Inc. | Lee K.H.,TissueGene Inc. | Lee K.H.,Inha University
Cytotherapy | Year: 2012

Background aims. TissueGene-C (TG-C) represents a cell-mediated gene therapy for localized delivery of allogeneic chondrocytes expressing transforming growth factor (TGF)-β1 directly to the damaged knee joint. Untransduced human chondrocytes (hChonJ cells) have also been incorporated into the TG-C product at a 3:1 ratio with TGF-β1-expressing chondrocytes (hChonJb#7) in order to help fill in the defect and as target cells for the actions of the expressed TGF-β1. Methods. A phase I dose-escalating clinical trial was performed to evaluate the safety and biologic activity of TG-C in patients with advanced osteoarthritis of the knee joint (full thickness cartilage defect) that was refractory to existing non-operative therapies. Following a single intra-articular injection into the joint space of the damaged knee, patients were monitored for safety, and an evaluation was performed to assess the pharmacokinetics and biologic activity of TG-C. Results. There were no treatment-related serious adverse events. Swelling, effusion and minor localized reactions such as warming sensation or itching were observed in a dose-dependent manner at the injection site. Knee evaluation scores seemed to indicate a dose-dependent trend toward efficacy; however, patient numbers were not sufficient to determine statistical significance. Conclusions. Overall, there were no significant safety issues related to the administration of TG-C, with only some minor injection site reactions observed. Additionally, knee scoring analyzes indicated a possibility that TG-C may contribute to improvement of arthritic symptoms. More study is warranted to evaluate further the safety and determine the potential efficacy of TG-C. © 2012 Informa Healthcare.

Lee S.-K.,Inha University
European Journal of Clinical Nutrition | Year: 2010

Although indicators of central obesity have been suggested as a better alternative to body mass index (BMI), yet mixed results exist. This study examined whether waist circumference (WC) was better in identifying metabolic disorders than BMI at two time points. This study used nationally representative 1998 and 2005 Korea National Health and Nutrition Examination Survey data sets. Odds ratios from logistic regressions and area under the curves (AUC) were calculated. BMI and WC showed similar level of odds ratios (1.1-1.6) to diabetes, hypertension, dyslipidemia and having two or three metabolic syndrome criteria. The AUC comparison, however, indicated that, in only women, WC was a better discriminator for diabetes, hypertension and having two or three metabolic syndrome criteria. No meaningful differences were found between 1998 and 2005. Prospective studies to weigh practical and clinical relevance are needed to assert the use of WC over BMI in clinical and public health settings. © 2010 Macmillan Publishers Limited All rights reserved.

OBJECTIVES: The α and β cells of pancreatic islet release important hormones in response to intracellular Ca increases that result from Ca releases through the inositol 1,4,5-trisphoshate receptor (IP3R)/Ca channels. Yet no systematic studies on distribution of IP3R/Ca channels have been done, prompting us to investigate the distribution of all 3 IP3R isoforms.METHODS: Immunogold electron microscopy was performed to determine the presence and the relative concentrations of all 3 IP3R isoforms in 2 major organelles secretory granules (SGs) and the endoplasmic reticulum of α and β cells of rat pancreas.RESULTS: All 3 IP3R isoforms were present in SG membranes of both cells, and the IP3R concentrations in SGs were ~2-fold higher than those in the endoplasmic reticulum. Moreover, large halos shown in the electron microscope images of insulin-containing SGs of β cells were gap spaces that resulted from separation of granule membranes from the surrounding cytoplasm.CONCLUSIONS: These results strongly suggest the important roles of SGs in IP3-induced, Ca-dependent regulatory secretory pathway in pancreas. Moreover, the accurate location of SG membranes of β cells was further confirmed by the location of another integral membrane protein synaptotagmin V and of membrane phospholipid PI(4,5)P2. © 2014 by Lippincott Williams & Wilkins.

The effect of phenol and resorcinol on hydrochloric acid leaching of Ti-rich slag is investigated. The leaching rate is exponentially proportional to acid and phenol concentrations. Any metal-phenol complexes decomposed by chloride ions should considerably increase the leaching rate by playing a role of active transport. Furthermore, phenols are expected to have a synergistic effect on the hydrochloric acid leaching of metal oxides. The additives such as methyl alcohol, ethyl alcohol and ethylene glycol improve the leaching efficiency in a chloride medium. It is observed that resorcinol with ethylene glycol acts as a better additive in the leaching of Ti-rich slag. The results will have significant impact on the production of upgraded feed stock (Synthetic Rutile) from Ti-rich slag. © 2013 Elsevier B.V.

Lengthening of photon storage time has been an important issue in quantum memories for long distance quantum communications utilizing quantum repeaters. Atom population transfer into an auxiliary spin state has been adapted to increase photon storage time of photon echoes. In this population transfer process phase shift to the collective atoms is inevitable, where the phase recovery condition must be multiple of 2π to satisfy rephasing mechanism. Recent adaptation of the population transfer method to atomic frequency comb (AFC) echoes [Afzelius et al., Phys. Rev. Lett. 104, 040503 (2010)], where the population transfer method is originated in a controlled reversible inhomogeneous broadening technique [Moiseev and Kroll, Phys. Rev. Lett. 87, 173601 (2001)], however, shows contradictory phenomenon violating the phase recovery condition. This contradiction in AFC is reviewed as a general case of optical locking applied to a dilute medium for an optical depth-dependent coherence leakage resulting in partial retrieval efficiency. © 2010 Optical Society of America.

Kim D.,Inha University | Griffith D.,U.S. National Institute of Standards and Technology | Golmie N.,U.S. National Institute of Standards and Technology
IEEE Communications Letters | Year: 2010

In Orthogonal Frequency Division Multiplex (OFDM) wireless networks such as 3GPP LTE and IEEE 802.16 WiMAX, the scheduler should allocate more resources to users with lower channel quality, such as users near the edge of the Base Station (BS) coverage area who are attempting handovers. In conventional queue-based models, this feature has not been considered in Call Admission Control (CAC) so far. In this letter, we propose a new ring-based model of the BS coverage area to allow a more detailed and accurate analysis. We determine mobility-related parameters such as call dropping probability due to mobility, and validate our results using simulations. © 2006 IEEE.

Kim D.W.,Yonsei University | Lee H.J.,Inha University | Tomizuka M.,University of California at Berkeley
IEEE Transactions on Fuzzy Systems | Year: 2010

This paper addresses stabilization problems for a nonlinear system via a sampled-data fuzzy controller. The nonlinear system is assumed to be exactly modeled in Takagi-Sugeno's form, at least locally. Unlike the conventional direct discrete-time design approach based on an approximate discrete-time model, the sampled-data fuzzy controllers are designed based on an exact discrete-time model. Sufficient design conditions are formulated in terms of linear matrix inequalities. It is shown that whenever the exact discrete-time fuzzy model is asymptotically stabilizable via the sampled-data fuzzy controller uniformly bounded in the state, then so is the original nonlinear system. A numerical example is given to illustrate the effectiveness of the proposed methodology. © 2010 IEEE.

Lee H.-H.,Inha University | Hill J.T.,University of Texas at Austin
International Journal of Mobile Communications | Year: 2013

This study investigates the utilitarian and hedonic consumer value perceptions of mobile marketing based on the short message service (SMS) and examines the moderating effect of situational involvement. The study uses service-dominant logic as the conceptual framework and employs a 2 (controllability) 2 (message type) 2 (situational involvement) between-subjects factorial design. The findings indicate significant main effects of controllability on both utilitarian and hedonic perceptions and the type of message only on utilitarian perceptions. Situational involvement had a significant. Moreover, the results show significant moderating role of situational involvement with controllability and a three-way effect of factors on both perceived utilitarian and hedonic perceptions. Copyright © 2013 Inderscience Enterprises Ltd.

Azeez A.A.,Kyung Hee University | Rhee K.Y.,Kyung Hee University | Park S.J.,Inha University | Hui D.,Kyung Hee University | Hui D.,University of New Orleans
Composites Part B: Engineering | Year: 2013

The review renders a short background on the research work carried out on epoxy clay nanocomposites. Clays are one of the ideal nano reinforcements for polymers because of their high intercalation chemistry and aspect ratio. Epoxy clay nanocomposites are finding vast applications in various industries like aerospace, defense, automobile, etc. The physical and chemical properties of the epoxy systems are influenced by the processing techniques, clay modifier and curing agents used for the preparation of nanocomposites. The clay morphology (intercalation/exfoliation) of the nanocomposites is also depended on the above parameters. So the emphasis of the present work is to highlight these parameters on morphology and the final mechanical, thermal and barrier properties of the nanocomposites. The proposed applications of the epoxy clay nanocomposites are also discussed. © 2012 Elsevier Ltd. All rights reserved.

Li G.,Chungbuk National University | Phan A.-H.,Chungbuk National University | Kim N.,Chungbuk National University | Park J.-H.,Inha University
Applied Optics | Year: 2013

A method for synthesizing a 360° computer-generated spherical hologram of real-existing objects is proposed. The whole three-dimensional (3-D) information of a real object is extracted by using a depth camera to capture multiple sides of the object. The point cloud sets which are obtained from corresponding sides of the object surface are brought into a common coordinate system by point cloud registration process. The modeled 3-D point cloud is then processed by hidden point removal method in order to identify visible point set for each spherical hologram point. The hologram on the spherical surface is finally synthesized by accumulating spherical waves from visible object points. By reconstructing partial region of the calculated spherical hologram, the corresponding view of the 3-D real object is obtained. The principle is verified via optical capturing using a depth camera and numerical reconstructions. © 2013 Optical Society of America.

Ham B.S.,Inha University
Optics Express | Year: 2010

A photon echo storage-time extension protocol is presented by using a phase locking method in a three-level backward propagation scheme, where phase locking serves as a conditional stopper of the rephasing process in conventional two-pulse photon echoes. The backward propagation scheme solves the critical problems of extremely low retrieval efficiency and π rephasing pulse-caused spontaneous emission noise in photon echo based quantum memories. The physics of the storage time extension lies in the imminent population transfer from the excited state to an auxiliary spin state by a phase locking control pulse. We numerically demonstrate that the storage time is lengthened by spin dephasing time. © 2010 Optical Society of America.

Jo T.,Inha University
Soft Computing | Year: 2014

This research is concerned with the improved version of table-based matching algorithm as the approach to text categorization tasks. It is intended to tackle the three problems in encoding texts into numerical vectors and the unstable performance by the fluctuations from text lengths in the previous version. In this research, we encode texts into tables rather than into numerical vectors, define the similarity measure between two tables which is always as a normalized value between zero and one, and apply it to the tasks of text categorization. As the benefits from this research, we expect better performance by solving the three problems resulting from encoding texts into numerical vectors, and more stable performance by improving the previous version. Therefore, we empirically validate the proposed approach through the four sets of experiments, with respect to both performance and stability. © 2014 Springer-Verlag Berlin Heidelberg.

Kim D.K.,Inha University | Griffith D.,U.S. National Institute of Standards and Technology | Golmie N.,U.S. National Institute of Standards and Technology
IEEE Transactions on Wireless Communications | Year: 2010

Call Admission Control (CAC) between heterogeneous networks, such as an integrated 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) network and a Wireless Local Area Network (WLAN), plays an important role to utilize the system resources in a more efficient way. In this paper, we propose that the preference to the WLAN is determined based on the traffic load in the WLAN and the location of the cellular users. Our analysis relies on a previous study that divides the 3G cellular coverage area into zones based on the amount of resources that are required to support a connection to a mobile user. Using this model, we derive new call blocking and handoff failure probabilities as well as new call and handoff attempt failure probabilities. Through simulations, we investigate proper preference settings by changing the WLAN load in a 3 ring-based sector with a WLAN hotspot. © 2010 IEEE.

Kim G.-W.,Kyungpook National University | Kim J.,Inha University
Smart Materials and Structures | Year: 2013

This paper presents a bio-inspired mechanism for the performance enhancement of piezoelectric power generation in vibration energy harvesting. A compliant bistable mechanism for vibration energy harvesting was explored based on the negative stiffness inspired by the auditory hair bundle structures. The proposed mechanism consists of a compliant, four-bar linkage system to mimic the hair bundle structure inside an inner ear. Our initial prototype energy harvester demonstrates that the compliant bistable mechanism featuring negative stiffness outperforms the conventional vibration energy harvester in the infra-low frequency range (1-10 Hz). © 2013 IOP Publishing Ltd.

Hwang J.Y.,Electronics and Telecommunications Research Institute | Lee S.,Electronics and Telecommunications Research Institute | Chung B.-H.,Electronics and Telecommunications Research Institute | Cho H.S.,Electronics and Telecommunications Research Institute | Nyang D.,Inha University
Information Sciences | Year: 2013

In this paper we present a novel group signature scheme for dynamic membership which enables fine-grained control over the release of user information. This scheme could be widely used for various anonymity-based applications such as privacy-preserving data mining and customized anonymous authentication owing to a useful property called controllable linkability. A valid signer is able to create signatures that hide his or her identity as normal group signatures but can be anonymously linked regardless of changes to the membership status of the signer and without exposure of the history of the joining and revocation. From signatures, only linkage information can be disclosed, with a special linking key. Using this controllable linkability and the controllable anonymity of a group signature, anonymity may be flexibly or elaborately controlled according to a desired level. To begin construction of our scheme, we first introduce the Decision Linear Combination (DLC) assumption in a so-called gap Diffie-Hellman group where the DDH problem is tractable but the CDH problem is hard, and we prove that this assumption can be guaranteed in generic bilinear groups. To identify security requirements more precisely, we formally present definitions of anonymity, traceability, non-frameabilty, and linkability. We then prove that our scheme achieves all these security properties in the random oracle model. Our scheme supporting controllable linkability yields a short signature that is only 33.3% longer than the best-known normal group signature. Furthermore, we show that our scheme is comparable to the group signature scheme in terms of the amount of computation for basic operations such as signing, verification, and the key update caused by revocation. Finally, using the linkability for dynamic membership, computation overhead in opening signer's identity can be significantly reduced or minimized. © 2012 Elsevier Inc. All rights reserved.

Ku J.H.,Kyung Hee University | Jung I.H.,Kyung Hee University | Rhee K.Y.,Kyung Hee University | Park S.J.,Inha University
Composites Part B: Engineering | Year: 2013

The effect of atmospheric pressure plasma treatment of polypropylene (PP) on the peel strength and shear strength between PP and aluminum plates was studied. The optimal treatment number was determined by measuring the changes in the contact angle, paint adhesion strength, and Scotch tape peel strength as a function of treatment number. FTIR and AFM analyses were conducted to determine the chemical and physical changes on the surface of the PP due to the atmospheric pressure plasma treatment. T-peel and SLS tests were performed using untreated PP/aluminum and plasma-treated PP/aluminum specimens to determine the effect of treatment on the peel strength and shear strength of PP/aluminum composites. The results showed that eight plasma treatments were optimal, and the contact angle was reduced from ∼91° to ∼53°. The results also showed that peel and shear strengths improved by ∼42% and ∼44%, respectively, after eight times of treatment. The improved bonding strength was attributed to the increased surface roughness and newly created hydrophilic functional group (C=O) on the polypropylene surface caused by the atmospheric pressure plasma treatment. © 2012 Elsevier Ltd. All rights reserved.

Hwang K.,Inha University
Journal of Craniofacial Surgery | Year: 2016

ABSTRACT: The aim of this study is to introduce an easy method of reducing the depressed and impacted segment in a nasomaxillary buttress fracture.Through the gingiva-labial vestibular incision, the fracture segments were exposed. A blunt end of the Cottle elevator was inserted to the cleft of the fracture segments. An upward and lateral force was applied until the impacted segment was released and reduced to its anatomical position. Then, the segments were fixed with a miniplate.Fifteen patients (12 males, 3 females, mean age: 34.5?±?11.7 years) were operated on. In 14 patients, the fragments were reduced in the anatomical position and secondary surgery was not required. In 1 patient, however, the infraorbital rim could not be reduced enough through a gingival incision and a secondary surgery was performed to reduce the orbital rim.A blunt end of the Cottle elevator is shallow and long enough to be inserted into the cleft and strong enough to transfer the force to reduce it into its anatomical position. This reduction technique using a Cottle elevator is easy and can be used for reducing the depressed and impacted segment in nasomaxillary buttress fractures. © 2016 by Mutaz B. Habal, MD.

Park S.,University of Texas at Austin | Park S.,Inha University | An J.,University of Texas at Austin | Potts J.R.,University of Texas at Austin | And 3 more authors.
Carbon | Year: 2011

We prepared hydrazine-reduced materials from both graphite oxide (GO) particles, which were not exfoliated, and completely exfoliated individual graphene oxide platelets, and then analyzed their chemical and structural properties by elemental analysis, XPS, TGA, XRD, and SEM. Both reduced materials showed distinctly different chemical and structural properties from one another. While hydrazine reduction of graphene oxide platelets produced agglomerates of exfoliated platelets, the reduction of GO particles produced particles that were not exfoliated. The degree of chemical reduction of reduced GO particles was lower than that of reduced graphene oxide and the BET surface area of reduced GO was much lower than that of reduced graphene oxide. © 2011 Elsevier Ltd. All rights reserved.

Huang H.,La Jolla Institute for Allergy and Immunology | Jeon M.-S.,La Jolla Institute for Allergy and Immunology | Jeon M.-S.,Inha University | Liao L.,Scripps Research Institute | And 5 more authors.
Immunity | Year: 2010

Tagging the cell surface receptor with ubiquitin is believed to provide a signal for the endocytic pathway. E3 ubiquitin ligases such as Cbl-b and Itch have been implicated in T cell activation and tolerance induction. However, the underlying mechanisms remain unclear. We describe that in mice deficient in the E3 ubiquitin ligases Cbl-b and Itch, T cell activation was augmented, accompanied by spontaneous autoimmunity. The double-mutant T cells exhibited increased phosphorylation of the T cell receptor-ζ (TCR-ζ) chain, whereas the endocytosis and stability of the TCR complex were not affected. TCR-ζ was polyubiquitinated via a K33-linkage, which affected its phosphorylation and association with the ζ chain-associated protein kinase Zap-70. The juxtamembrane K54 residue in TCR-ζ was identified to be a primary ubiquitin conjugation site, whose mutation increased its phosphorylation and association of TCR-ζ and Zap-70. Thus, the present study reveals unconventional K33-linked polyubiquitination in nonproteolytic regulation of cell-surface-receptor-mediated signal transduction. © 2010 Elsevier Inc.

Park D.,Inha University
IEEE Transactions on Wireless Communications | Year: 2016

We consider two-user MIMO broadcast and interference channels in which confidential messages intended for each receiver are kept secret from the other receiver. The confidential secrecy rates are nonconvex functions of transmit covariance matrices, which makes it intractable to find optimal transmit covariance matrices analytically. In the MIMO broadcast channels, we prove the weighted secrecy sum rate maximization has zero duality gap and KKT conditions are necessary conditions for the optimal solution. We apply the block successive lower-bound maximization technique to nonconvex weighted secrecy sum rate maximization problems. We also derive numerical algorithms for MIMO interference channels and Gaussian wiretap channels with a cooperative jammer. Every limit point achieved by the proposed algorithms is a local optimal solution that satisfies the KKT conditions. Numerical results show that the proposed algorithms outperform existing suboptimal algorithms in terms of secrecy rates. © 2015 IEEE.

Huh J.,Yonsei University | Park C.,Yonsei University | Kwon Y.K.,Inha University
Journal of Chemical Physics | Year: 2010

We theoretically consider the commensurability problem of AB diblock lamellar phase confined between parallel plates, in cylinder, and in sphere calculating the free energy of confined lamellar phase which is generalized in terms of dimensionality of confinement (d) and conformational asymmetry (ε). We find that the first-order layer-addition transition of lamellar layers parallel to the confining surface (L∥) becomes suppressed as the dimensionality of confinement increases. For lamellae confined in curved space, the conformational asymmetry alters the location of layer-addition transition point and the stability of L∥ against nonconcentric layers. When the surface-preferential block becomes flexible, the radius of cylindrically or spherically confined space at the layer-addition transition, where the number of A-B layers of L∥ changes from l layers to l+1 layers, increases if l is odd and decreases otherwise due to the tendency of less flexible block filling innermost layer. The curved space also weakens the stability L∥ competing with nonconcentric layers when the surface-preferential block becomes less flexible. The phase maps in the parameter space of conformational asymmetry and degree of confinement are constructed for different cases of the confinement dimensionality and the surface fields, demonstrating the effects of various system variables on the confined lamellar structures. © 2010 American Institute of Physics.

Hong J.-Y.,University of Suwon | Wie J.J.,Inha University | Xu Y.,University of Suwon | Park H.S.,University of Suwon
Physical Chemistry Chemical Physics | Year: 2015

Graphene aerogel is a relatively new type of aerogel that is ideal for energy storage applications because of its large surface area, high electrical conductivity and good chemical stability. Also, three dimensional interconnected macropores offer many advantages such as low density, fast ion and mass transfer, and easy access to storage sites. Such features allow graphene aerogels to be intensively applied for electrochemical capacitor applications. Despite the growing interest in graphene aerogel-based electrochemical capacitors, however, the graphene aerogels still suffer from their low capacitive performances and high fragility. Both relatively low capacitance and brittleness of physically crosslinked graphene aerogels remain a critical challenge. Until now, a number of alternative attempts have been devoted to overcome these shortcomings. In this perspective, we summarize the recent research progress towards the development of advanced graphene aerogel-based electrochemical capacitors according to the different approaches (e.g. porosity, composition and structure controls). Then, the recently proposed chemical strategies to improve the capacitive performances and mechanical durability of graphene aerogels for practical applications are highlighted. Finally, the current challenges and perspectives in this emerging material are also discussed. © 2015 the Owner Societies.

You C.-Y.,Inha University | Jung M.-H.,Sogang University
Journal of Applied Physics | Year: 2013

We investigate the dependence of switching current density on the junction sizes in the in-plane spin transfer torque nanopillar structures by using micromagnetic simulations. While the macrospin model predicts weak dependence of switching current density on the junction sizes, we find that the switching current density is a sensitive function of the junction sizes. It can be explained with the complicated spin configurations and dynamics during the switching process. The detail spin configurations and dynamics are determined by spin wave excitation with the finite wave vector, which is related with the exchange coupling energy and junction shape. © 2013 American Institute of Physics.

The mud shrimp Upogebia major (Upogebiidae: Decapoda: Crustacea) is a common species on muddy and sandy mud tidal flats in the west coast of Korea. They reside in Y-shaped burrows that can extend up to more than 2 meters below the sediment surface. They feed on suspended detritus carried into their burrow by the beating of their pleopods and captured by their hairy first two pairs of thoracic legs. Mud shrimp burrows provide a habitat for a variety of small organisms such as crabs, shrimps, polychaetes, and mollusks. Ovigerous females are observed from December to May. Females deposit eggs only once per breeding season. They start hatching in March and the pelagic larvae of first zoea appear in March and April, followed by benthic settlement in May. Growth over the first year is rapid, and females deposit their first eggs in the third breeding season, 31 months after their settlement. Adult shrimps live for 4~5 years. Depth of the burrow increases with body length. The deep burrows provide refuge from predators and physical stress, allowing the shrimps to survive for a long time. The mud shrimps supply oxygen-rich water to their deep burrows, and exert a great influence on the structure and metabolism of the tidal flat benthic community. However, recently this type of mud shrimp has posed a serious threat to the Korean clam industry along the west coast of Korea. The extensive burrowing shrimp populations suddenly invaded the tidal flats from 2010 where the clams (Ruditapes philippinarum) are raised. As a consequence, clam production has decreased by about 10% over the past three years in some Korean clam beds. Therefore, the objective of this study is to review the biology of this mud shrimp in order to seek solutions to control the burrowing of these shrimps.

Cho W.Y.,Soonchunhyang University | Jang J.Y.,Kyung Hee University | Lee D.H.,Inha University
Clinical Endoscopy | Year: 2011

The desire to better recognized such malignancies, which may be difficult to distinguish from inflammation or trauma, has accelerated the development of endoscopy with new optical technologies. Narrow-band imaging is a novel endoscopic technique that may enhance the accuracy of diagnosis using narrow-bandwidth filters in a red-green-blue sequential illumination system. Autofluorescence imaging is based on the detection of natural tissue fluorescence emitted by endogenous molecules. I-scan technology using a digital filter that modifies normal images through software functions, is the newly developed image-enhanced endoscopic technology from PENTAX. Flexible spectral imaging color enhancement enhances the visualization of mucosal structure and microcirculation by the selection of spectral transmittance with a dedicated wavelength. Confocal laser endomicroscopy images were collected with an argon beam with a scanning depth of 0 (epithelium) to 250 μm (lamina propria) and analyzed using the reflected light. © 2011 The Korean Society of Gastrointestinal Endoscopy.

Jun Y.C.,Sandia National Laboratories | Jun Y.C.,Inha University | Reno J.,Sandia National Laboratories | Ribaudo T.,Sandia National Laboratories | And 6 more authors.
Nano Letters | Year: 2013

We present a new type of electrically tunable strong coupling between planar metamaterials and epsilon-near-zero modes that exist in a doped semiconductor nanolayer. The use of doped semiconductors makes this strong coupling tunable over a wide range of wavelengths through the use of different doping densities. We also modulate this coupling by depleting the doped semiconductor layer electrically. Our hybrid approach incorporates strong optical interactions into a highly tunable, integrated device platform. © 2013 American Chemical Society.

Yakhshiev U.T.,Inha University
Physical Review C - Nuclear Physics | Year: 2013

In the present work we discuss the modifications of infinite nuclear matter properties. The modifications are performed in the framework of the in-medium modified Skyrme model. The model is developed to study the properties of in-medium nucleons and nucleonic systems. The mesonic sector of the model contains the nonlinear pion fields propagating in the nuclear medium. The properties of in-medium pions are defined by the pion-nucleus optical potential. The isospin-breaking part of the optical potential and the isospin-breaking effects in the mesonic sector generate the isospin-breaking effects in the baryonic sector. Further, the isospin-breaking effects in the baryonic sector are related to the asymmetric-matter properties. First, we discuss the binding energy per nucleon and the bulk properties of the isospin-symmetric nuclear matter. Then, we include the isospin-breaking effects and discuss the asymmetric-matter properties. © 2013 American Physical Society.

Kim M.-Y.,Inha University | Wheeler M.F.,University of Texas at Austin
Computers and Mathematics with Applications | Year: 2014

We provide a general framework of multiscale discontinuous Galerkin methods developed in Buffa et al. (2006), Hughes et al. (2006) for general second-order partial differential equations. We establish stability of the method and prove the error estimates. © 2014 Elsevier Ltd. All rights reserved.

Motamedi S.,University of Malaya | Song K.-I.,Inha University | Hashim R.,University of Malaya
Materials and Structures/Materiaux et Constructions | Year: 2015

Recently, ground improvement has become much more feasible. Chemical stabilization is a quick and affordable approach to enhancing soil characteristics. An important avenue of research is discovering alternative materials for use in soil enhancement. Pulverized fuel ash (PFA), which is a waste byproduct of coal power plants, has been shown to reduce the environmental risks and costs involved in construction. In this study, a series of unconfined compressive tests were performed for various mixtures of cement, PFA, and sand; the tests considered both the curing period and the optimum moisture content (OMC). In addition, multiple variable linear regression was used to analyze laboratory data in order to obtain an empirical relationship that can be used to predict the unconfined compressive strength (UCS) of a PFA–cement–sand mixture. The accuracy of the model was verified using statistical indices. The first objective of this study was to assess the effects of PFA content on the UCS of the mixture. The second was to investigate the impact of the OMC on the UCS. The focal point of this study was its derivation of a relationship that can be used to estimate the UCS on the basis of existing variables. The results indicated that PFA can strengthen sand in terms of the UCS and that excessive PFA in a mixture may adversely affect the UCS of a medium. Therefore, a mixture must have an optimum proportion of compounds. The OMC plays a vital role in enhancing UCS. The UCS of different mixtures can be predicted with an acceptable level of accuracy by using the relationship derived in this study. © 2014, RILEM.

Park S.-J.,Inha University | Kim B.-J.,Korea Institute of Carbon Convergence Technology
Springer Series in Materials Science | Year: 2015

Traditionally, the application of carbon fibers has been limited to very special fields such as aerospace and military because of their high cost. However, various techniques for low-cost carbon fibers are under development in terms of using low-cost precursors, low-cost manufacturing processes, and even functional coating methods. Moreover, future applications of carbon fibers can widen not only as structural reinforcements but also in information technology-based applications such as housings for electric devices, smart cloths, and healthcare items. In this chapter, we will cover the carbon fibers and their composites in recent various applications. In particular, there are classified as a low-cost production technique of carbon fibers for general industries, thin carbon fibers for extreme industries, and functional carbon fibers for smart composites. © Springer Science+Business Media Dordrecht 2015.

Park S.,Inha University | Ruoff R.S.,Korea Basic Science Institute
Current Opinion in Colloid and Interface Science | Year: 2015

This review documents our contributions to the synthesis of chemically-modified graphene (CMG) materials. We focus on methods for the preparation of homogenous colloidal suspensions of CMGs and procedures for the chemical reduction of graphene oxide, along with techniques for the structural elucidation of graphene oxide and reduced graphene oxide materials. We conclude with an outline of the persisting chemical challenges and current limitations of practical applications. © 2015 Elsevier Ltd.

The potential of using maximum entropy modeling for landslide susceptibility mapping is investigated in this paper. Although the maximum entropy model has been applied widely to species distribution modeling in ecology, its applicability to other kinds of predictive modeling such as landslide susceptibility mapping has not yet been investigated fully. In the present case study of Boeun in Korea, multiple environmental factors including continuous and categorical data were used as inputs for maximum entropy modeling. From the optimal setting test based on cross-validation, the effective feature type for continuous data representation was found to be a hinge feature and its combination with categorical data showed the best predictive performance. Factor contribution analysis indicated that distances from lineaments and slope layers were the most influential factors. From interpretations on a response curve, steeply sloping and weathered areas that consisted of excessively drained granite residuum soils were very susceptible to landslides. Predictive performance of maximum entropy modeling was slightly better than that of a logistic regression model which has been used widely to assess landslide susceptibility. Therefore, maximum entropy modeling is shown to be an effective prediction model for landslide susceptibility mapping. © 2014, Springer-Verlag Berlin Heidelberg.

Kim M.-Y.,Inha University | Wheeler M.F.,University of Texas at Austin
Computers and Mathematics with Applications | Year: 2014

We investigate DG-DG domain decomposition coupling using mortar finite elements to approximate the solution to general second-order partial differential equations. We weakly impose an inflow boundary condition on the inflow part of the interface and the Dirichlet boundary condition on the elliptic part of the interface via Lagrange multipliers. We obtain the matching condition by imposing the continuity of the total flux through the interface and the continuity of the solution on the elliptic parts of the interface. The diffusion coefficient is allowed to be degenerate and the mortar interface couples efficiently the multiphysics problems. The (discrete) problem is solvable in each subdomain in terms of Lagrange multipliers and the resulting algorithm is easily parallelizable. The subdomain grids need not match and the mortar grid may be much coarser, giving a two-scale method. Convergence results in terms of the fine subdomain scale h and the coarse mortar scale H are then established. A non-overlapping parallelizable domain decomposition algorithm (Arbogast et al., 2007) reduces the coupled system to an interface mortar problem. The properties of the interface operator are discussed. © 2013 Elsevier Ltd. All rights reserved.

Gallagher T.,Virginia Commonwealth University | Kim J.,Inha University | Oldenbroek M.,University of Texas Southwestern Medical Center | Kerr R.,Howard Hughes Medical Institute | You Y.-J.,Virginia Commonwealth University
Journal of Neuroscience | Year: 2013

In Caenorhabditis elegans, satiety quiescence mimics behavioral aspects of satiety and postprandial sleep in mammals.Onthe basis of calciumimaging, genetics, and behavioral studies, here we report that a pair of amphid neurons, ASI, is activated by nutrition and regulates worms' behavioralstatesspecificallypromotingsatietyquiescence;ASIinhibitstheswitchfromquiescencetodwelling(abrowsingstate)andaccelerates the switch from dwelling to quiescence. The canonical TGFβ pathway, whose ligand is released from ASI, regulates satiety quiescence. The mutants of a ligand, a receptor and SMADs in the TGFβ pathway all eat more and show less quiescence than wild-type. The TGFβ receptor in downstream neurons RIM and RIC is sufficient for worms to exhibit satiety quiescence, suggesting neuronal connection from ASI to RIM and RICis essential for feeding regulationthroughtheTGFβ pathway.ASIalso regulates satiety quiescence partlythroughcGMPsignaling; restoring cGMP signaling in ASI rescues the satiety quiescence defect of cGMP signaling mutants. From these results, we propose that TGFβ and cGMP pathways in ASI connect nutritional status to promotion of satiety quiescence, a sleep-like behavioral state. © 2013 the authors.

Woo S.,Inha University
KSCE Journal of Civil Engineering | Year: 2016

The objective of this research is to quantify the anticipated impact of labor productivity during scheduled overtime on total project duration. In order to meet this objective, a Monte Carlo simulation model of variability and continuous deterioration of labor productivity during scheduled overtime of labor productivity during scheduled overtime was developed. The pattern of the productivity decline was modeled by the productivity curves reported by Business Roundtable in 1974 which is considered the most comprehensive study of construction overtime and labor productivity. Also, the techniques of statistical inference were used to fit a theoretical distribution to the productivity data obtained from CII research published in 1994. After performing the hypothesis tests, the lognormal distribution was selected to represent variability of daily labor performance during scheduled overtime in this simulation model. This research shows that estimating the impact of working overtime on the project duration without considering labor productivity decline leads to overestimation of the effectiveness of working overtime. This research also demonstrates that simulation analysis of scheduled overtime provides a more in-depth analysis of the overall impact on project schedule. The simulation analysis allows a project manager to assess and analyze the effectiveness of working different overtime options and to choose the right overtime option providing required schedule acceleration. © 2016 Korean Society of Civil Engineers and Springer-Verlag Berlin Heidelberg

Jin S.-E.,Yonsei University | Jin H.-E.,Lawrence Berkeley National Laboratory | Hong S.-S.,Inha University
Expert Opinion on Therapeutic Targets | Year: 2015

Introduction: L-type amino acid transporter 1 (LAT1) is one of the amino acid transporters. It is overexpressed in various types of cancer cells, while it is produced restrictedly in normal tissues.Areas covered: We discuss its characteristics in cancer cells compared with normal cells. We also mention the current applications to target LAT1 for anticancer therapy focusing on prognostic biomarkers, radio-labeled tumor imaging reagents, amino acid-stapled prodrugs, LAT1-mediated enhanced transport of anticancer drugs and LAT1 inhibitors.Expert opinion: LAT1 can be a versatile target to promisingly develop transporter-based drugs with enhanced drug delivery potential for anticancer therapy. © 2015 Informa UK, Ltd.

Chung S.-Y.,Inha University | Chung S.-Y.,Nalphates LLC | Kim J.-G.,Korea Basic Science Institute | Kim Y.-M.,Korea Basic Science Institute | Lee Y.-B.,Korea Basic Science Institute
Advanced Materials | Year: 2011

The three-dimensionally isolated morphology of secondary iron phosphide phases in a polycrystalline LiFePO4 matrix is determined using a combination of electron tomography in high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), energy-dispersive X-ray spectroscopy (EDS), and electron energy-loss spectroscopy (EELS). The present evidence shows that the enhanced bulk electronic conductivity in LiFePO 4 has no relation to secondary metallic phases at the grain boundaries. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

Emission of gas at charged states of lithium ion batteries (LIBs) is a significant problem because it causes swelling and deformation of LIBs. In this study, the gas generation mechanism is investigated and preventative measures are developed. Decomposition of the electrolyte solution related to residual lithium compounds on the surface of LiNi0.5Co0.2Mn 0.3O2 (NCM523) and to the structural change in the cathode active material is investigated as two main mechanisms of gas generation in LIB cells. NCM523 particles are encapsulated in a continuous lithium lanthanum titanium oxide (LLTO) thin layer to inhibit gas-generating reactions. The LLTO layer fixes free lithium of the cathode surface and effectively suppresses side reactions between the charged cathode active material and the electrolyte solution, resulting in substantial reduction of the gas generation. In addition, LLTO-coated NCM523 shows improved capacity retention without any loss of capacity or rate performance because LLTO is a good conductor of Li ions. © 2013 the Owner Societies.

Kim Y.S.,Inha University
Aesthetic Plastic Surgery | Year: 2014

Background: Subbrow blepharoplasty (SBB) addresses lateral hooding of the upper eyelid skin, a shortcoming of classical upper blepharoplasty. Therefore, SBB is widely used by plastic surgeons in Korea and Japan. The aim of this study is to improve postoperative results and to minimize a relapse of existing SBB by the use of a supraorbital rim periosteal suture fixation technique. Methods: An upper incision is made along the inferior margin of the eyebrow. A lower incision, which is determined according to necessary amount of skin excision, is made vertically, deep to the posterior fascia of the obicularis oculi muscle (OOM). Then, skin, OOM, and posterior fascia of the OOM are excised en bloc. An upper skin flap dissection is extended to the width of 1 cm. The posterior fascia of the OOM in the inferior flap is pulled up and three transverse 5-0 nylon sutures are placed to fix it to the periosteum and the sub-brow fat of the supraorbital rim temporally to the supraorbital nerve. A margin of upper flap level is usually a suitable position for fixation. Thirty-six patients underwent SBB using the supraorbital rim periosteal suture fixation technique from July 2007 to June 2012. Results: Thirty-six patients underwent SBB and were followed up for an average of 27 months. The follow-up period ranged from 8 months to 6 years. Their mean age at the time of surgery was 55 years. Thirty-four patients (94.4 %) were satisfied with the surgical results, however, two patients (5.6 %) complained about dimpling at the periosteal suture fixation point. Administration of two focal injections of triamcinolone acetonide resulted in relief and disappearance of the dimpling. Conclusion: We report our experience with a subbrow blepharoplasty using suture fixation of the OOM in the inferior flap to the supraorbital rim periosteum at the margin of the upper flap after an elliptical excision of subbrow skin. Our method of SBB has the advantage of ensuring the continuance of surgical results and minimizing the risk of relapse by placement of suraorbital rim periosteal fixation sutures. Level of evidence IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors http://www.springer.com/00266. © 2013 Springer Science+Business Media New York and International Society of Aesthetic Plastic Surgery.

Kim H.-N.,University of Ottawa | El-Saddik A.,University of Ottawa | El-Saddik A.,United Arab Emirates University | Jo G.-S.,Inha University
Decision Support Systems | Year: 2011

Collaborative Filtering (CF), one of the most successful technologies among recommender systems, is a system assisting users to easily find useful information. One notable challenge in practical CF is the cold start problem, which can be divided into cold start items and cold start users. Traditional CF systems are typically unable to make good quality recommendations in the situation where users and items have few opinions. To address these issues, in this paper, we propose a unique method of building models derived from explicit ratings and we apply the models to CF recommender systems. The proposed method first predicts actual ratings and subsequently identifies prediction errors for each user. From this error information, pre-computed models, collectively called the error-reflected model, are built. We then apply the models to new predictions. Experimental results show that our approach obtains significant improvement in dealing with cold start problems, compared to existing work. © 2011 Elsevier B.V. All rights reserved.

Park W.H.,Inha University
LUTS: Lower Urinary Tract Symptoms | Year: 2010

Low bladder compliance means an abnormal volume and pressure relationship, and an incremental rise in bladder pressure during the bladder filling. It is well known that at the time bladder capacity decreases, intravesical pressure increases, and the risk of upper deterioration increases. Hypocompliance is usually thought to be the range from 1.0 to 20.0 mL/cmH2O. Though the exact cause of hypocompliance is not known, it may be caused by changes in the elastic and viscoelastic properties of the bladder, changes in detrusor muscle tone, or combinations of the two. Management aims at increasing bladder capacity with low intravesical pressure. The main is a medical therapy with antimuscarinics combined with clean intermittent catheterization. The results are sometimes unsatisfactory. Various drugs or agents through the mouth or the bladder, including oxybutynin, new antimuscarinics, capsaicin and resiniferatoxin were tried. Among them botulinum toxin-A is promising. Some patients eventually required surgical intervention in spite of the aggressive medical therapy. Finally most patients undergo the surgical treatment including autoaugmentation, diversion, and augmentation cystoplasty. Among them augmentation cystoplasty still seems the only clearly verified treatment method. © 2010 Blackwell Publishing Asia Pty Ltd.

Alam M.N.,Shahjalal University of Science and Technology | Sarkar S.M.,Inha University
Reaction Kinetics, Mechanisms and Catalysis | Year: 2011

A nanostructured mesoporous MCM-41 supported N-heterocyclic carbene-Pd (NHC-Pd) complex was prepared through the reaction of an ionic liquid immobilized onto MCM-41 with palladium acetate. The MCM-41-supported NHC-Pd complex could serve as a highly effective catalyst for the Suzuki cross-coupling reaction under aqueous conditions. Furthermore, the Pd(II) catalyst was recovered by a simple filtration from the reaction mixture and reused without a significant loss of its catalytic activity. The heterogeneous catalyst was also air-stable and thermally stable to allow its easy use. © 2011 Akadémiai Kiadó, Budapest, Hungary.

Jalal A.,Kyung Hee University | Uddin M.,Inha University | Kim T.-S.,Kyung Hee University
IEEE Transactions on Consumer Electronics | Year: 2012

Video-based human activity recognition systems have potential contributions to various applications such as smart homes and healthcare services. In this work, we present a novel depth video-based translation and scaling invariant human activity recognition (HAR) system utilizing R transformation of depth silhouettes. To perform HAR in indoor settings, an invariant HAR method is critical to freely perform activities anywhere in a camera view without translation and scaling problems of human body silhouettes. We obtain such invariant features via R transformation on depth silhouettes. Furthermore, in R transforming depth silhouettes, shape information of human body reflected in depth values is encoded into the features. In R transformation, 2D feature maps are computed first through Radon transform of each depth silhouette followed by computing 1D feature profile through R transform to get the translation and scaling invariant features. Then, we apply Principle Component Analysis (PCA) for dimension reduction and Linear Discriminant Analysis (LDA) to make the features more prominent, compact and robust. Finally, Hidden Markov Models (HMMs) are used to train and recognize different human activities. Our proposed system shows superior recognition rate over the conventional approaches, reaching up to the mean recognition rate of 93.16% for six typical human activities whereas the conventional PC and IC-based depth silhouettes achieved only 74.83% and 86.33% ,while binary silhouettes-based R transformation approach achieved 67.08% respectively. Our experimental results show that the proposed method is robust, reliable, and efficient in recognizing the daily human activities. © 2011 IEEE.

Park J.O.,Kyung Hee University | Rhee K.Y.,Kyung Hee University | Park S.J.,Inha University
Applied Surface Science | Year: 2010

In this study, the effect of silane treatment of Fe3O 4 on the magnetic and wear properties of Fe3O 4/epoxy nanocomposites was investigated. Fe3O4 nanopowders were prepared by coprecipitation of iron(II) chloride tetrahydrate with iron(III) chloride hexahydrate, and the surfaces of Fe3O 4 were modified with 3-aminopropyltriethoxysilane. The magnetic properties of the powders were measured on unmodified and surface-modified Fe3O4/epoxy nanocomposites using SQUID magnetometer. Wear tests were performed on unmodified and surface-modified Fe3O 4/epoxy nanocomposites under the same conditions (sliding speed: 0.18 m/s, load: 20 N). The results showed that the saturation magnetization (M s) of surface-modified Fe3O4/epoxy nanocomposites was approximately 110% greater than that of unmodified Fe 3O4/epoxy nanocomposites. This showed that the specific wear rate of surface-modified Fe3O4/epoxy nanocomposites was lower than that of unmodified Fe3O4/epoxy nanocomposites. The decrease in wear rate and the increase in magnetic properties of surface-modified Fe3O4/epoxy nanocomposites occurred due to the improved dispersion of Fe3O4 into the epoxy matrix. © 2010 Elsevier B.V.

This work is concerned with the determination of leaching characteristics of titania rich slag by hydrochloric acid. This can be considered as an alternative to selective iron dissolution and insolubilization of TiO 2 in the form of synthetic rutile. The relevant criteria for titania slag leaching in hydrochloric acid are studied, including the acid concentration, experimental parameters and solid/liquid ratio, which controls the acid/slag molar ratio as well as effect of reduction. Ilmenite or metalized ilmenite, when smelted/melted under thermal plasma gives titania rich slag and iron metal as products. Preparation of upgraded feedstock from titania slag depends on leachability of it by mineral acids. The data reveals that the optimum conditions involve working with 6M acid with a solid/liquid ratio of 1/20 at room temperature for 1 hour, using slag ground to less than 74μm. The results will have significant impact on production of upgraded feed stock. © 2011 The Institution of Chemical Engineers.

Saipullah K.-M.,University Technical Malaysia Melaka | Kim D.-H.,Inha University
Optical Engineering | Year: 2012

Original spectral features contain information pertinent to certain target spectral features. Without an efficient spectral feature extraction method, the target detection performance might be degraded. We present spectral feature extraction techniques based on the Fourier domain for use in target detection. These feature extraction methods are the Fourier magnitude (FM), Fourier phase (FP), and Fourier coefficient selection (FCS) methods. In our target detection experiments, we compared the proposed methods to the principle component analysis (PCA) and independent component analysis (ICA) methods and the original spectral features. The experiment results show that the FCS target detection accuracy is 95.75%, whereas the accuracies of the FM, FP, PCA, ICA methods, and the original spectral features are 86.76%, 36.28%, 84.51%, 74.49%, and 78.92%, respectively. The average feature extraction times of the proposed methods are 223% faster than that found for the PCA and 304% faster than the ICA methods. © 2012 Society of Photo-Optical Instrumentation Engineers (SPIE).

We investigate the dependence of the switching current density on the exchange stiffness constant in the spin transfer torque magnetic tunneling junction using micromagnetic simulations. Since the widely accepted analytic expression of the switching current density is based on the macrospin model, there is no dependence on the exchange stiffness constant. However, we found strong dependence of the switching current density on the exchange stiffness constant because of the formation of complex spin configurations. © 2012 The Japan Society of Applied Physics.

Moulay D.,University of Le Havre | Aziz-Alaoui M.A.,University of Le Havre | Kwon H.-D.,Inha University
Mathematical Biosciences and Engineering | Year: 2012

Since the 1980s, there has been a worldwide re-emergence of vectorborne diseases including Malaria, Dengue, Yellow fever or, more recently, chikungunya. These viruses are arthropod-borne viruses (arboviruses) transmitted by arthropods like mosquitoes of Aedes genus. The nature of these arboviruses is complex since it conjugates human, environmental, biological and geographical factors. Recent researchs have suggested, in particular during the Réunion Island epidemic in 2006, that the transmission by Aedes albopictus (an Aedes genus specie) has been facilitated by genetic mutations of the virus and the vector capacity to adapt to non tropical regions. In this paper we formulate an optimal control problem, based on biological observations. Three main efforts are considered in order to limit the virus transmission. Indeed, there is no vaccine nor specic treatment against chikungunya, that is why the main measures to limit the impact of such epidemic have to be considered. Therefore, we look at time dependent breeding sites destruction, prevention and treatment efforts, for which optimal control theory is applied. Using analytical and numerical techniques, it is shown that there exist cost effective control efforts.

Koh I.-S.,Inha University | Lee Y.,Yonsei University
IEEE Transactions on Antennas and Propagation | Year: 2012

A closed-form expression of the dyadic Green's function is formulated for an impedance half-plane, which is written in terms of the incomplete cylindrical function of Poisson form. Due to the branch-cut of the logarithm function that is required to calculate the input argument of the incomplete cylindrical function, the closed-form representation consists of two formulations. Since the closed-form expression contains a singularity at ρ =0, the small argument expansion of the expression is also derived to rigorously characterize the behavior of the function at ρ 0. The previously-reported complete asymptotic expansion for the Sommerfeld integral for an impedance half-plane is not accurate for practically important cases such as near-earth propagation and/or when the surface is highly conductive. Hence, in this paper, a new complete asymptotic series of the Sommerfeld integral are derived for the case that the existing asymptotic series is not accurate. The two asymptotic series not only allow efficient numerical computation but also provide more accurate results for virtually all propagation scenarios. Based on the two asymptotic series, the complete asymptotic series of the dyadic Green's function is derived. All derived formulations are numerically verified, and their accuracies are investigated. © 1963-2012 IEEE.

Kwan J.,Inha University
Journal of Echocardiography | Year: 2014

Significant advances in three-dimensional echocardiography (3DE) have made this modality a powerful diagnostic tool in the cardiology clinic. It can provide accurate and reliable measurements of chamber size and function. In addition, 3DE offers novel views and comprehensive anatomic definition of valvular and congenital abnormalities by rendering 3D contoured images of the structures. It is also useful in monitoring the effectiveness of surgical or percutaneous transcatheter interventions. With demonstrations of efficacy in various clinical settings, 3DE has become a complementary part of the routine diagnostic armamentarium. However, 3DE is regarded as simply a tool for 3D volume or image rendering. If we confine the role of 3DE to this, it will remain a complementary tool to two-dimensional echocardiography (2DE) in the future. Three-dimensional echocardiography has roles beyond 3D volume or image rendering. Three-dimensional echocardiography can acquire a full volume dataset in a single shot, and with combined use of the multiplanar reconstructive mode, it can provide anatomically well-defined 2D planes from the full volume dataset. Hence, by omitting routine 2DE work, 3DE may save time for image acquisition and allow more precise and reproducible review or measurement. Taking this perspective into account, 3DE can be a suitable modality for use as a substitute for 2DE in daily practice. With further advances of 3DE and development of a unified review system capable of display and geometrical assessment of 2D as well as 3D images, 3DE will represent a new paradigm shift in echocardiographic examination in the future. © 2013 Japanese Society of Echocardiography.

Lee H.J.,Inha University | Kim D.W.,Hanbat National University
Information Sciences | Year: 2016

Performance-recoverable intelligent digital redesign (IDR) in a fast sampling limit is proposed for fuzzy tracking controllers with time-varying references. IDR uses a delta operator and a piecewise linear - rather than constant - approximation of the reference improve the state-matching performance for both an extremely small and a large sampling period T∈R>0, respectively. It is proved that the analog control performance is recovered by the proposed intelligently digitally redesigned sampled-data controller in three perspectives - controller gain, stability, and closed-loop trajectory - when T goes to zero. © 2015 Elsevier Inc. All rights reserved.

Yang E.J.,Korea Polar Research Institute | Ha H.K.,Inha University | Kang S.-H.,Korea Polar Research Institute
Deep-Sea Research Part II: Topical Studies in Oceanography | Year: 2015

We investigated the microzooplankton community and its grazing impact on major phytoplankton groups in the Chukchi Sea and in the western Canada Basin during the period July-August 2010. The study area was divided into three regions based on topography, hydrographic properties and trophic conditions: (1) a productive region over the Chukchi Sea shelf (CSS) with high phytoplankton biomass dominated by diatoms, (2) an oligotrophic region over the Northwind Abyssal Plain (NwAP) with low phytoplankton biomass dominated by picophytoplankton, and (3) the Northwind Ridge (NwR), over which waters were dominated by picophytoplankton and diatoms. The spatial distribution of microzooplankton biomass and its composition were related to differences in phytoplankton biomass and assemblage composition in the three water masses. Heterotrophic dinoflagellates (HDF) and ciliates were significant components of microzooplankton populations. Athecate HDF was the most important component in the CSS, where diatoms were dominant. Naked ciliates were dominant microzooplankton in the NwR. Microzooplankton grazing rate varied by the assemblage composition of both phytoplankton and microzooplankton. Microzooplankton was capable of consuming an average of 71.7±17.2% of daily phytoplankton production. Growth rates of smaller phytoplankton (i.e., picophytoplankton and autotrophic nanoflagellates) and grazing rates on them were higher than rates for diatoms. Microzooplankton grazed more on picophytoplankton (PP grazed=89.3±20.5%) and autotrophic nanoflagellates (PP grazed=82.3±22.5%) than on diatoms (PP grazed=62.5±20.5%). The dynamics of predator and prey populations were almost balanced in waters in which smaller phytoplanktons were dominant. Picophytoplankton production was consumed by microzooplankton allowing transfer to larger consumers. On average, microzooplankton grazed 62.5% of the diatom production in the waters we studied, indicating that the classical food chain (with carbon flux from diatoms to copepods) is likely operational and of significance in this region. Overall, microzooplankton grazing was an important process controlling phytoplankton biomass and composition in the Chukchi Sea and the western Canada Basin during early summer. © 2014 Elsevier Ltd.

Chung S.-Y.,Inha University | Chung S.-Y.,Nalphates LLC | Kim Y.-M.,Korea Basic Science Institute | Choi S.-Y.,Korea Institute of Materials Science
Advanced Functional Materials | Year: 2010

The control of unexpectedly rapid Li intercalation reactions without structural instability in olivine-type LiFePO4 nanocrystals is one of the notable scientific advances and new findings attained in materials physics and chemistry during the past decade. A variety of scientific studies and technological investigations have been carried out with LiFePO4 to elucidate the origins of many peculiar physical aspects as well as to develop more effective synthetic processing techniques for better electrochemical performances. Among the several features of LiFePO4 that have attracted much interest, in this article we address four important issues-regarding doping of aliovalent cations, distribution of Fe-rich secondary metallic phases, nanoparticle formation during crystallization, and antisite Li/Fe partitioning-by means of straightforward atomic-scale imaging and chemical probing. The direct observations in the present study provide significant insight into alternative efficient approaches to obtain conductive LiFePO 4 nanocrystals with controlled defect structures. Olivine-type ordered LiFePO4 (see picture) has been studied during the past decade to elucidate the origins of its many peculiar physical aspects for achieving better electrochemical performance. Based on straightforward atomic-scale imaging and chemical probing, four different issues regarding LiFePO4 are discussed in this article, giving a brief overview on the valuable experimental demonstrations made to date. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Jeong S.-H.,Inha University | Mwafy A.M.,United Arab Emirates University | Elnashai A.S.,University of Illinois at Urbana - Champaign
Engineering Structures | Year: 2012

Fragility analyses are conducted in this study to evaluate the relative seismic safety margins of seismic code-designed multi-story reinforced concrete (RC) buildings with varying input motion intensity, ductility level and configuration. Structural variations are accounted for by using twelve buildings [13] with diverse structural systems, heights and ductile detailing. The design peak ground acceleration (PGA) is also varied. The reference structures also include regular and irregular buildings in order to cover a wide spectrum of contemporary mid-rise buildings. Incremental dynamic analyses (IDAs) are deployed using the twelve inelastic fiber-based simulation models of the reference structures and sixty natural ground motions recorded on different soil conditions with a wide range of spectral amplifications. The regression analyses of the selected response quantities show that the soil condition has a marginal effect on the demand-ground motion intensity relationships when adopting spectral acceleration to characterize the ground shaking intensity. The damage state probabilities of wall-frame structures designed to high PGA and ductility levels do not satisfactorily achieve the most favorable safety objectives. Fragilities are reduced by decreasing the design PGA due to the higher contribution of gravity loads to the details of the building design. Using extensive results from twelve buildings subjected to sixty ground motions, a relationship is proposed to enable the quantifying of the Life Safety limit state probabilities of code-compliant mid-rise RC buildings. © 2011 Elsevier Ltd.

Chae M.J.,Korea Institute of Construction Technology | Yoo H.S.,Inha University | Kim J.Y.,Korea Institute of Construction Technology | Cho M.Y.,Korea Institute of Construction Technology
Automation in Construction | Year: 2012

A wireless sensor system has been suggested and tested in the place of forty five sensors of five types among the sensors used extensively in suspension bridges to prove the viability of wireless sensor network in actual implementation. ZigBee (IEEE 802.15.4) is used for short-distance communications among sensors and Code Division Multiple Access (CDMA) for long-distance wireless communications with remote locations. A data logger is integrated with a sensor and ZigBee into a one-channel data logger that combines sensor, logger and digital communication modules to allow for the addition or replacement of a sensor with ease. Lastly, the wireless sensor network-based bridge health monitoring system proposed herein is developed in the form of an application that is intended to ensure universal applicability and designed to maximize the ease of wireless sensor network. © 2011 Elsevier B.V. All Rights Reserved.

Xue N.,University of Texas at Dallas | Chang S.-P.,Inha University | Lee J.-B.,University of Texas at Dallas
Journal of Microelectromechanical Systems | Year: 2012

With the growing demand in noncontact detection of human diseases, this paper presents an implantable passive wireless pressure sensor using an inductively coupled wireless sensing technique, particularly designed to monitor the intraocular pressure (IOP) of glaucoma patients. The microfabricated IOP sensor consists of a planar spiral gold coil inductor, a two-parallel-gold-plate (metal-insulator-metal) capacitor, and a SU-8 pressure-sensitive diaphragm. The IOP sensor is fully encapsulated inside biocompatible SU-8 stacking layers to isolate the IOP sensor from the biological tissue medium environment. By measuring the impedance phase dip frequency shift from the external coil, the IOP signal can be obtained through the implanted IOP sensor. The optimized size of the manually wound external coil was investigated. The readout distance is up to 6 mm from the implanted sensor. Characterization results show that the microfabricated IOP sensor has relatively high sensitivities7035 ppm/mmHg in air and 3770 ppm/mmHg in saline mediumwith pressure resolution lower than 1 mmHg, which is adequate for IOP monitoring application. © 2012 IEEE.

Goo B.-C.,Korea Railroad Research Institute | Kim M.-H.,Inha University
Journal of Mechanical Science and Technology | Year: 2012

Aluminum alloy matrix composites reinforced with SiC particles (AMC) are potential materials applicable to weight reduction of friction materials. We developed two AMC: A356/SiC and A390/SiC. 30 μm and 60 μm SiC particles with volume fraction of 20% were dispersed in the matrix of A356 and A390 alloys. When the temperature of the liquid alloy was higher than that of the melting point, SIC particles floated up to the surface because of the low viscosity, high surface tension and interfacial energy. To mix the ceramic particles, the aluminum alloy was in the mushy state near the solidus temperature, 610°C for A356 and 645°C for A390. Metallurgical, mechanical and tribological characteristics of the manufactured composites were evaluated. © 2012 The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg.

Muradian K.,State Institute of Gerontology | Vaiserman A.,State Institute of Gerontology | Min K.-J.,Inha University | Fraifeld V.E.,Ben - Gurion University of the Negev
Nutrition, Metabolism and Cardiovascular Diseases | Year: 2015

Aims: Accumulating data suggest that food supplementation with seaweeds which traditionally are an important part of food culture in South-East Asian countries might lead to essential health benefits. In this short review, we summarize findings from experimental studies on the effects of fucoxanthin (a carotenoid derived from brown seaweeds) on lipid metabolism, adiposity, and related conditions and discuss the possible underlying mechanisms. Data synthesis: Supplementation of fucoxanthin or its derivatives consistently attenuated body and visceral fat weight gain, lipid accumulation in the liver, decreases insulin resistance, and improves the plasma lipid profile in rodents fed a high-fat diet. It should however be noted that in diabetic/obese KK-Ay mice with genetically compromised insulin signaling, fucoxanthin might increase the plasma levels of cholesterol and low-density lipoproteins. The anti-obesity effects of fucoxanthin are apparently mediated by the hormones leptin and adiponectin through their common target AMK-activated protein kinase, resulting in downregulation of lipogenic enzymes and upregulation of lipolytic enzymes. Fucoxanthin also suppresses adipocyte differentiation and induces the expression of uncoupling proteins in visceral adipose tissue. Conclusions: The results of experimental studies suggest that consumption of fucoxanthin and its derivatives as nutritional supplements is a promising option for prevention and treatment of obesity and a wide variety of related pathologies, including metabolic syndrome, type 2 diabetes, and heart disease. Yet, clinical trials are warranted to assess a therapeutic value of fucoxanthin. © 2015 Elsevier B.V.

Ryu H.-Y.,Inha University
Optical and Quantum Electronics | Year: 2016

The spontaneous emission (SE) rate in GaN-based vertical light-emitting diode (LED) structures can be modified significantly depending on the local density of states near the high-reflectance mirror. In this study, this Purcell effect in vertical LED structures is investigated numerically using finite-difference time-domain simulation. The Purcell factor of vertical LED structures is found to vary periodically with the p-GaN thickness, while it is almost independent of the n-GaN thickness, indicating strong influence of the p-type electrode reflector on the SE modification. The peak of the Purcell factor is obtained to be as high as 1.5 at a properly chosen p-GaN thickness, which leads to substantial increase in the internal quantum efficiency (IQE) of LEDs. Since the influence of the Purcell factor on IQE becomes more conspicuous as IQE decreases, the Purcell effect of vertical LED structures is expected to mitigate the green-gap and the efficiency droop problems of current LED technologies. © 2015, Springer Science+Business Media New York.

Ryu H.-Y.,Inha University | Shim J.-I.,Hanyang University
Optics Express | Year: 2011

We investigate the effects of current spreading on the efficiency droop of InGaN blue light-emitting diodes with lateral injection geometry based on numerical simulation. Current crowding near the mesa edge and the decrease in the current spreading length with current density are shown to cause significant efficiency droop. It is found that the efficiency droop can be reduced considerably as the uniformity of current spreading is improved by increasing the resistivity of the p-type current spreading layer or decreasing the sheet resistance of the n-GaN layer. The droop reduction is well interpreted by the uniformity of carrier distribution in the plane of quantum wells. © 2011 Optical Society of America.

Kim D.W.,Hanbat National University | Lee H.J.,Inha University
Fuzzy Sets and Systems | Year: 2012

This paper presents a new direct discrete-time design methodology of a sampled-data observer-based output-feedback fuzzy controller for a class of nonlinear system that is exactly modeled in Takagi-Sugenos form at least locally. A fundamental yet challenging issue in this direction is the unavailability of the exact discrete-time model of the nonlinear plant in a closed form. In contrast to the earlier works that are based on an approximate discrete-time model thus the stability obtained in the design step is not preserved in the implementation step, we employ an exact discrete-time fuzzy model in an integral form. Sufficient asymptotic stabilization conditions are investigated in the discrete-time Lyapunov sense. We then show that the resulting sampled-data controller indeed asymptotically stabilizes the nonlinear plant. An example is provided to illustrate the effectiveness of the proposed methodology. © 2012 Elsevier B.V. All rights reserved.

Kim B.-J.,Jeonju Institute of Machinery and Carbon Composites | Park S.-J.,Inha University
International Journal of Hydrogen Energy | Year: 2011

Nickel/graphite hybrid materials were prepared by mixed acid treatment of graphite flakes, following metal nanoparticle deposition. The textural properties were studied by BET surface area measurement and t-plot methods with N2/77 K adsorption isotherms. The hydrogen storage characteristics of the nickel/graphite at 298 K and 10 MPa were studied using a pressure-composition-temperature apparatus. The pore structure of the materials was studied as a function of processing conditions. In the optimum material, the hydrogen storage capacity was as high as 4.48 wt.%. The total amount of storage was not proportional to the specific surface area or metal content of the adsorbate. A dipole-induced model on nickel/carbon surfaces is proposed for the hydrogen storage mechanism. © 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.

Yang S.Y.,Cornell University | Kim B.N.,Cornell University | Zakhidov A.A.,Cornell University | Taylor P.G.,Cornell University | And 4 more authors.
Advanced Materials | Year: 2011

Microelectrodes based on poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS) are able to record the oxidation of catecholamines released from chromaffin cells during exocytosis with a high signal-to-noise ratio. This result represents a new capability for organic electronics that could lead to devices that interface with the nervous system in novel ways. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ryu H.-Y.,Inha University | Jeon K.-S.,LG Corp | Kang M.-G.,LG Corp | Choi Y.,LG Corp | Lee J.-S.,LG Corp
Optics Express | Year: 2013

We investigate the dependence of various efficiencies in GaNbased vertical blue light-emitting diode (LED) structures on the thickness and doping concentration of the n-GaN layer by using numerical simulations. The electrical efficiency (EE) and the internal quantum efficiency (IQE) are found to increase as the thickness or doping concentration increases due to the improvement of current spreading. On the contrary, the light extraction efficiency (LEE) decreases with increasing doping concentration or n-GaN thickness by the free-carrier absorption. By combining the results of EE, IQE, and LEE, wall-plug efficiency (WPE) of the vertical LED is calculated, and the optimum thickness and doping concentration of the n-GaN layer is found for obtaining the maximum WPE. © 2012 Optical Society of America.

Kim K.J.,Inha University | Tsiftsis T.A.,Technological Educational Institute of Lamia | Schober R.,University of British Columbia
IEEE Transactions on Vehicular Technology | Year: 2011

In this paper, a semiblind iterative receiver is proposed for coded multiple-input-multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) systems. A novel iterative extended soft-recursive least square (IES-RLS) estimator for joint channel and frequency offset estimation is introduced. Extrinsic bit information obtained from the channel decoder and expected symbol decisions obtained from the demodulator are simultaneously exploited by the IES-RLS. The proposed receiver combines the MIMO data demodulator, the proposed channel estimator, and the channel decoder in an iterative manner to yield an improved bit error rate (BER) performance. To arrive at a feasible algorithm, the first-order linearization of the received vector signal with respect to the frequency offset is used in the IES-RLS channel estimator. The BER performance, a constellation-constrained mutual information analysis, and an EXIT chart analysis are used to verify the effectiveness of the proposed receiver. Simulation results show the superiority of the proposed semiblind receiver, compared with conventional semiblind receivers. © 2010 IEEE.

Jhon M.S.,Carnegie Mellon University | Jhon M.S.,Sungkyunkwan University | Choi H.J.,Inha University
Polymer | Year: 2010

The novelty lies on the molecular level investigation of the end group functionality on rheological properties of fractionated, monodisperse oligomeric perfluoropolyethers (PFPEs) with various molecular weights and chain-end functionalities in this study. A sharp transition observed in the slope of the shear viscosity at a critical molecular weight for PFPEs was interpreted based on temporal tube mechanism caused by end group agglomeration of strong functional polar end groups. The temperature dependence of the shear viscosity was found to yield an Arrhenius form, determining the flow activation energy and hydrodynamic volume. The flow activation energy was also compared to the activation energy for surface diffusion to examine the role of end group-solid surface interaction. Modified Cole-Cole plots for storage and loss moduli along with polymer relaxation show the microstructural changes due to the interaction of PFPE end-group, which alters effective molecular weights. © 2010 Elsevier Ltd. All rights reserved.

We explored the effects of the boning corsets on women’s health so that the body’s physiological response to the corset’s pressure was measured by the changes in heart rate, blood flow, perspiration, metabolism and their subjective pressure sensation when exercise. The corsets were reconstructed with or without boning inside the corsets with 10–20 % smaller waist girth of participants. Five women in their twenties volunteered to be our test subjects. The results vary according to the corset type and time period of exercise process. The peak corset pressure appeared almost 7 kPa with the most boning-type Corset B. Compared to the control group that did not wear a corset, the heart rate of the corset wearers decreased up to 15–20 % at most changes of Corset C, blood flow at the finger tips decreased 36 % at most changes of Corset C. And perspiration decreased up to 90 % at maximum of Corset A. The energy expenditure of corset wearers increased 14 % at most of Corset B due to higher corset pressure in sides even at the same activity level, which means that more energy is required to make the body torso move. Physiological responses were different according to corset type, that is, the most boning-type corset showed highest clothing pressure at 2 points, under armpit and near the side waist point and highest changes of energy metabolism, but showed least changes of heart rate and blood flow among the corsets. This is for it enhances blood circulation during exercise movement of body as seesaw effects of leveraging boning wires on blood vessels. Thus we can say the most boning type of corset affected the physiological responses and body comfort positively specially when body exercise, eventhough the boning inside corset enhanced clothing pressure partially. © 2015, The Korean Fiber Society and Springer Science+Business Media Dordrecht.

Lee S.,Inha University | Kwon O.C.,Sungkyunkwan University
International Journal of Hydrogen Energy | Year: 2011

The potential of partial ammonia substitution to improve the safety of hydrogen use was evaluated computationally, using counterflow nonpremixed ammonia/hydrogen/air flames at normal temperature and pressure. The ammonia-substituted hydrogen/air flames were considered using a recent kinetic mechanism and a statistical narrow-band radiation model for a wide range of flame strain rates and the extent of ammonia substitution. The effects of ammonia substitution on the extinction limits and structure, including nitrogen oxide (NOx) and nitrous oxide (N2O) emissions, of nonpremixed hydrogen/air flames were investigated. Results show reduction of the high-stretch extinction (i.e.; blow-off) limits, the maximum flame temperature and the concentration of light radicals (e.g.; H and OH) with ammonia substitution in hydrogen/air flames, supporting the potential of ammonia as a carbon-free, clean additive for improving the safety of hydrogen use in nonpremixed hydrogen/air flames. For high-stretched flames, however, NO x and N2O emissions substantially increase with ammonia substitution even though ammonia substitution reduces flame temperature, implying that chemical effects (rather than thermal effects) of ammonia substitution on flame structure are dominant. Radiation effects on the extinction limits and flame structure are not remarkable particularly for high-stretched flames. © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Kim J.-H.,Pusan National University | Shin S.A.,Pusan National University | Park J.B.,Pusan National University | Song C.E.,KAIST | And 4 more authors.
Macromolecules | Year: 2014

We designed and synthesized two low-band-gap conjugated copolymers with alternating difluorinated benzoselenadiazole (DFDTBSe) and ethylhexyloxy (EH)- or octyldodecyloxy (OD)-substituted benzo[1,2-b:4,5-b′]dithiophene (BDT) building blocks. PEHBDT-DFDTBSe and PODBDT-DFDTBSe have optical band gap energies of 1.66 and 1.69 eV, respectively, and HOMO energy levels of -5.44 and -5.43 eV, respectively. The different alkyloxy side chains in the polymers affect the molecular packing and ordering in active-layer films blended with [6,6]-phenyl-C71 butyric acid methyl ester (PC71BM). The PEHBDT-DFDTBSe:PC71BM film comprises predominantly "face-on" crystal structures with short π-π stacking distances (3.69 Å) while PODBDT-DFDTBSe:PC71BM has mostly "edge-on" structures according to two-dimensional grazing-incidence X-ray diffraction analysis. Bulk heterojunction solar cells were fabricated with an inverted structure of ITO/ethoxylated polyethylenimine/polymer:PC 71BM/MoO3/Ag. The device fabricated using the PEHBDT-DFDTBSe:PC71BM active layer shows a maximum power conversion efficiency (PCE) of up to 5.74%, which is the highest value reported for OPVs containing benzoselenadiazole and BDT-derivative polymers. A tandem solar cell was also fabricated using PEHBDT-DFDTBSe:PC71BM and poly(3-hexylthiophene):indene-C60-bisadduct as the top and bottom cell components, respectively; its maximum PCE was 7.15%. © 2014 American Chemical Society.

Kim S.H.,Inha University | Plutzky J.,Harvard University
Diabetes and Metabolism Journal | Year: 2016

Brown fat is a specialized fat depot that can increase energy expenditure and produce heat. After the recent discovery of the presence of active brown fat in human adults and novel transcription factors controlling brown adipocyte differentiation, the field of the study of brown fat has gained great interest and is rapidly growing. Brown fat expansion and/or activation results in increased energy expenditure and a negative energy balance in mice and limits weight gain. Brown fat is also able to utilize blood glucose and lipid and results in improved glucose metabolism and blood lipid independent of weight loss. Prolonged cold exposure and beta adrenergic agonists can induce browning of white adipose tissue. The inducible brown adipocyte, beige adipocyte evolving by thermogenic activation of white adipose tissue have different origin and molecular signature from classical brown adipocytes but share the characteristics of high mitochondria content, UCP1 expression and thermogenic capacity when activated. Increasing browning may also be an efficient way to increase whole brown fat activity. Recent human studies have shown possibilities that findings in mice can be reproduced in human, making brown fat a good candidate organ to treat obesity and its related disorders. ©2016 Korean Diabetes Association.

Jeong S.,Inha University
Clinical Endoscopy | Year: 2016

Biliary self-expandable metal stents (SEMS), a group of non-vascular stents, have been used in the palliative management of biliary obstruction around the world. However, there are still unmet needs in the clinical application of biliary SEMS. Comprehensive understanding of the SEMS is required to resolve the drawbacks and difficulties of metal stent development. The basic structure of SEMS, including the materials and knitting methods of metal wires, covering materials, and radiopaque markers, are discussed in this review. What we know about the physical and mechanical properties of the SEMS is very important. With an understanding of the basic knowledge of metal stents, hurdles such as stent occlusion, migration, and kinking can be overcome to develop more ideal SEMS. © 2016 Korean Society of Gastrointestinal Endoscopy.

This paper examines total factor productivity (TFP) growth, technical change and economies of scale measure of Korean fossil-fuel power generation companies (GENCOs) between 2001 and 2012. For the empirical investigation, we estimated the cost function along with specification tests in order to find the most appropriate empirical model. Empirical results show TFP deterioration, technical regress, and economies of scale for the study period. The optimal size of the Korean GENCOs was also found, which is employed in developing policies regarding TFP growth and technical advance. © 2015 Elsevier B.V.

Cho H.,Inha University
Vitamins and Hormones | Year: 2013

Protein tyrosine phosphatase 1B (PTP1B) is a negative regulator of the leptin and insulin signaling pathways. The important roles of PTP1B related to obesity and diabetes were confirmed by a deletion of PTP1B gene in mice. Mice with the whole body deletion of PTP1B were protected against the development of obesity and diabetes. When PTP1B gene was deleted selectively in the brain of mice, the major effects on weight and glucose control were consistent with the whole body deletion of PTP1B. This is in contrast to the muscle-, liver-, and adipocyte-specific deletion, which had no beneficial effects on obesity. While these results indicate the importance of neuronal PTP1B in maintaining energy homeostasis, the peripheral PTP1B is also being investigated for their potential roles in the control of energy balance. Validation of PTP1B as a therapeutic target for obesity and diabetes prompted efforts to develop potent and selective inhibitors of PTP1B. Among the small molecule inhibitors investigated, trodusquemine, which acts both centrally and peripherally, is currently in phase 2 clinical trials. An approach using PTP1B-directed antisense oligonucleotides is also in phase 2 clinical trials. © 2013 Elsevier Inc.

Choi K.-J.,Inha University
Korean Journal of Medical History | Year: 2016

Fujita Tsuguakira was a man who established Jahyeuiwon, a governmental medical facility, during the Residency-General Period and took over the presidency of a committee in the Japanese Government-General of Chosun after Chosun was annexed to Japanese. In addition, he is a man well qualified to be placed on the top of the list when discussing the Japanese colonial medicine in Chosun, considering his personal history of getting evolved in the colonial rule of Taiwan for seven years as an army surgeon. He led the colonial medicine in Chosun for nine years before and after the Japanese annexation of Korea. He was engaged in almost all the areas related to the colonial medicine such as anti-cholera projects, Hansung Sanitation Union, Deahan Hospital, Chosun Chongdokbu Hospital, Jahyeuiwon, medical schools affiliated to the Japanese Government-General of Chosun. In all respects, his life was in sync with the expansionist strategies of Imperial Japan. Especially, his deeds in Chosun was an "active aid to the instructions" from Army Minister Terauchi Masatake " as Sato Kozo testifies. Fujita was chosen by the military, and so he faithfully served the role given from it. The rewards that he received form the military attest to this fact. He took the position of Surgeon General in Army Medical Service on September, 1912, the top place that an army surgeon could hold. The position was first given to the officer who worked outside Japan proper, and he was the only army surgeon with no doctorial degree to receive such title except for Ishiguro Tadanori who was the first army surgeon in Japan. To sum up, Fujita was not a "doctor" but a "military officer". His walk of life mainly lay in the role of an aider adjusted to the ups and downs and the speeds of the plans of Imperial Japan to invade the continent. Therefore, the Japanese colonial medicine controlled by such man as Fujita in Chosun was inevitably studded with the military things. As a chief in the army medicine, what was important to him was the hospitals for managing the armed troops and projects for preventing infectious disease that could threaten the military sanitation. As a result, the medical service for those under the colonial rule was naturally put on the back burner. This study was conducted mainly based on Fujita's memoirs called Army Surgeon General Fujita Tsuguakira (1943), and accordingly it would be not without limitations. However, as he is a man who cannot be put aside when discussing the Japanese colonial medicine in Chosun, the records by this study of his life and past activities are expected to give no small amount of contribution to these discussions. © The Korean Society for the History of Medicine.

Chen H.-Y.,University of California at Los Angeles | Hou J.,University of California at Los Angeles | Hayden A.E.,University of California at Los Angeles | Yang H.,University of California at Los Angeles | And 2 more authors.
Advanced Materials | Year: 2010

(Figure Presented)A new silole-containing low-bandgap polymer is synthesized by replacing the 5-position carbon of PCPDTBT with a silicon atom (PSBTBT; see figure). Through experiments and computational calculations, we show that the material properties, particular the packing of polymer chains, can be altered significantly. As a result, the polymer changes from amorphous to highly crystalline with the replacement of the silicon atom. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA.

Son M.,Chungnam National University | Lee G.-H.,Inha University
Water Resources Research | Year: 2013

To investigate the effects of wave shape on cohesive sediment flux in shallow water environments, a one-dimensional vertical (1DV) model for cohesive sediment transport previously validated with field measurement is applied to conditions of skewed and asymmetric oscillatory flows. Cohesive sediments usually portray behaviors different from those of noncohesive sediments. This is mainly due to the flocculation process through which the density and the size of cohesive sediment change continuously. Therefore, a robust flocculation model is incorporated with a 1DV model in this study. Under the condition of skewed oscillatory flow (second-order Stokes wave-type oscillatory flow), the flux of cohesive sediment is significantly affected by the change of flow skewness, whereas the flux of noncohesive sediment of which size is 100 μm does not show a clear relationship with skewness. Under the condition of forward-leaning asymmetric oscillatory flow (saw-tooth wave-type oscillatory flow), the direction of cohesive sediment flux is negative, whereas the flux of noncohesive sediment shows the positive direction. The phase-lag effect is considered as the main mechanism of these behaviors. The interactional relationship between the settling velocity, the variation of concentration profile, and hydrodynamics of carrier fluid enhances the phase-lag effect and causes different behaviors in cohesive sediment compared to the flux of fine noncohesive sediment. ©2013. American Geophysical Union. All Rights Reserved.

β-Lapachone (β-lap) is a bioreductive agent that is activated by the two-electron reductase NAD(P)H quinone oxidoreductase 1 (NQO1). Although β-lap has been reported to induce apoptosis in various cancer types in an NQO1-dependent manner, the signaling pathways by which β-lap causes apoptosis are poorly understood. β-Lap-induced apoptosis and related molecular signaling pathways in NQO1-negative and NQO1-overexpressing MDA-MB-231 cells were investigated. Pharmacological inhibitors or siRNAs against factors involved in β-lap-induced apoptosis were used to clarify the roles played by such factors in β-lap-activated apoptotic signaling pathways. β-Lap leads to clonogenic cell death and apoptosis in an NQO1-dependent manner. Treatment of NQO1-overexpressing MDA-MB-231 cells with β-lap causes rapid disruption of mitochondrial membrane potential, nuclear translocation of AIF and Endo G from mitochondria, and subsequent caspase-independent apoptotic cell death. siRNAs targeting AIF and Endo G effectively attenuate β-lap-induced clonogenic and apoptotic cell death. Moreover, β-lap induces cleavage of Bax, which accumulates in mitochondria, coinciding with the observed changes in mitochondria membrane potential. Pretreatment with Salubrinal (Sal), an endoplasmic reticulum (ER) stress inhibitor, efficiently attenuates JNK activation caused by β-lap, and subsequent mitochondria-mediated cell death. In addition, β-lap-induced generation and mitochondrial translocation of cleaved Bax are efficiently blocked by JNK inhibition. Our results indicate that β-lap triggers induction of endoplasmic reticulum (ER) stress, thereby leading to JNK activation and mitochondria-mediated apoptosis. The signaling pathways that we revealed in this study may significantly contribute to an improvement of NQO1-directed tumor therapies.

Jo T.,Inha University
International Conference on Advanced Communication Technology, ICACT | Year: 2016

We concern this research with the table based KNN as the approach to the index optimization task. It may be interpreted into an instance of word classification, and the encoding scheme where words are encoded into tables improved the task word classification. In this research, words are encoded into tables and apply the table based KNN to the index optimization task. From this research, we expect the better and more stable performance than the traditional version, in this task. Therefore, this research is intended to provide the improved index optimization scheme. © 2016 Global IT Research Institute (GiRI).

We investigated the association between alcohol consumption and risk of cervical intraepithelial neoplasia (CIN) and cervical cancer, and determined whether these associations were modified by human papillomavirus (HPV) viral load in high-risk HPV-positive women participating in the Korean HPV cohort study (KHPV). Among the women recruited in the KHPV (n = 1,243) from March 2006 to December 2009, we analyzed normal cytology (n = 581) as control group, CIN1 (n = 299), CIN2/3 (n = 161), or cervical cancer (n = 202). Multinomial logistic analysis was performed to estimate multivariate-adjusted odds ratios (OR). Alcohol drinkers had an increased risk of CIN1 (OR = 2.18, 95% CI 1.22-3.89) compared with non-drinkers after adjusting for potential confounders. Subjects with more frequent alcohol consumption had a higher risk of CIN1 (p for linear trend <0.0001). Higher ethanol consumption was associated with an increased risk of CIN1 (p for linear trend = 0.0001). We also observed a synergistic effect between HPV viral load and alcohol consumption: drinkers with a high HPV viral load (≥100 RLU/PC) were associated with a significantly increased risk of CIN1 (OR = 19.1; 95% CI, 6.60-55.3, interaction p<0.001). There were no associations between alcohol drinking and CIN2/3 or cervical cancer. HPV viral load and alcohol was associated with the risk of CIN1 among high-risk HPV-positive women. This is the first demonstration that alcohol is an independent and combined risk factor of CIN1.

Jo T.,Inha University
International Conference on Advanced Communication Technology, ICACT | Year: 2016

This research proposes the table based AHC algorithm as the approach to the word clustering task. The results from encoding texts into tables were successful in the previous works on the text categorization and the text clustering, and if oppositely to the case of the text encoding, texts are assumed to be elements of each word, it becomes to be possible to encode words into tables. In this research, we map words into tables in the reverse direction to the text encoding, modify the AHC algorithm into the version where tables are given as its input, and apply the modified version of AHC to the word clustering task. In this research, we expect the better and more stable clustering performance, than the traditional version. Hence, this research provides the improved method of clustering words semantically. © 2016 Global IT Research Institute (GiRI).

Zhang N.,Jiangxi University of Finance and Economics | Wei X.,Inha University
Applied Energy | Year: 2015

This study examines and decomposes dynamic changes in total factor carbon emissions performance within the transportation sector in China, incorporating the impact of regional heterogeneity. For this purpose, we combine the metafrontier approach with the non-radial Luenberger productivity indicator to propose a new definition named the metafrontier non-radial Luenberger carbon emission performance index (MNLCPI). This total factor index includes the efficiency change, best-practice gap change, and metafrontier technology gap change indexes. This method is capable of measuring dynamic changes in total factor carbon emissions performance over time via the production frontier framework and can incorporate group heterogeneity and non-radial slack into its measurement of total factor carbon emission performance. Empirical results applying this method show a 6.2% increase in overall total factor carbon emissions performance for the 2000-2012 period. This growth in carbon emissions performance is mainly driven by technological innovation, and different growth patterns are observed across China's three main areas in transport sector. © 2015 Elsevier Ltd.

Jeong J.K.,Inha University
Journal of Materials Research | Year: 2013

Metal oxide optoelectronics is an emerging field that exploits the intriguing properties of the ns orbital-derived isotropic band structure as a replacement for traditional silicon-based electronics in advanced active-matrix information displays. Although the device performance of metal oxide thin film transistors (TFTs) has been substantially improved, the device reliability against external light and gate bias stress remains a critical issue. This paper provides a literature review of light-induced gate bias stress instability in metal oxide TFTs and explain the importance of photo-bias instability in the applications of metal oxide TFTs to optoelectronic device. The rationale of threshold voltage (V th) instability under the negative bias illumination stress (NBIS) condition is discussed in detail. The charge trapping/injection model, oxygen vacancy photoionization model, and ambient interaction model are described as plausible degradation mechanisms. Finally, the possible approaches to prevent NBIS-induced V th instability are proposed based on an understanding of the NBIS instability. Copyright © 2013 Materials Research Society.

Lim H.S.,Massachusetts Institute of Technology | Baek J.H.,Soongsil University | Park K.,Soongsil University | Shin H.S.,Inha University | And 2 more authors.
Advanced Materials | Year: 2010

(Figure Presented) Thermally stable superhydrophobic fabrics with multifunctionality were fabricated through the combination of sol-gel chemistry and electrospinning. MTES sols were electrospun into fibers, in which fiber morphology was controlled by the gelation time. The resulting superhydrophobic fabrics are not only very stable and heat-resistant but perform with high filtration efficiency, enabling emerging applications for smart materials and devices. © 2010 WILEY-VCH Verlag GmbH & CO. KGaA,.

Kwon O.-S.,University of Toronto | Jeong S.-H.,Inha University
Journal of Earthquake Engineering | Year: 2013

The unseating of decks is one of the most prevalent failure modes of bridges after earthquake events, as observed in the 2010 Chile Earthquake. Damaged bridges in Chile often had skew angles and were supported on elastomeric bearings. Similar bridge construction practices with decks supported on elastomeric bearings are also common in the central and eastern U.S. (CEUS). The seismic displacement demands on skewed bridges are more complicated than those on bridges without skew angles due to the coupling of translational modes with the rotational mode of vibration. The study presented in this article seeks to understand the seismic response of skewed bridge decks supported on elastomeric bearings. The scope of the study is limited to one- and two-span bridges, which constitute a large portion of bridge inventory in the CEUS. The vibration modes of skewed bridge decks are derived in closed form and the modes are compared when the gaps between the bridge deck and the abutment are open and when one of the gaps is closed due to seismic excitation. Nonlinear response history analyses are carried out to understand the effects of vertical ground motion, skew angles, aspect ratios, and different ground motion types on the seismic displacement demand in these cases. Amplification factors that approximate the increase in the displacement demand due to the skew angle are proposed. Copyright © A. S. Elnashai.

Pan J.H.,National University of Singapore | Zhao X.S.,National University of Singapore | Lee W.I.,Inha University
Chemical Engineering Journal | Year: 2011

Over the last decade, mesoporous TiO2 nanocrystalline films have been intensively investigated not only for fundamental research interest but also for technological applications. This critical review summarizes recent progress of the block copolymer-templated highly organized mesoporous TiO2-based films prepared via an evaporation-induced self-assembly (EISA) process and their photoelectrochemical applications. With a brief introduction to the principle of block copolymer self-assembly and EISA process, control of the cooperative self-assembly between Ti species and block copolymer in the sol solution as well as in the deposited films, aging under a controlled humid environment, and subsequent thermal treatment is described. Key experimental parameters for the preparation of highly organized mesoporous TiO2 films are analyzed. Applications of mesoporous TiO2-based films in photocatalytic reactions, catalytic chemical synthesis, dye-sensitized solar cells, and electrochromic and photochromic devices are discussed. The synthesis-component-structure-property relationship in mesoporous TiO2-based films is highlighted, and the perspectives in this rapidly developing field are suggested. © 2010 Elsevier B.V.

Lee S.,Inha University | Parks R.,University of Arizona | Burge J.H.,University of Arizona
Applied Optics | Year: 2012

We present a simple method to determine the relative distortion of axially symmetric lens systems. This method uses graphs to determine every parametric value instead of nonlinear minimization computation and is composed of an LCD screen to display a square grid pattern of pixel-wide spots and a set of analyzing processes for the spots in the image. The two Cartesian components of the spot locations are processed by a two-step linear least-square fitting to third-order polynomials. The graphs for the coefficients enable us to determine the amount of decentering of the camera lens axis with respect to the center of the image array and the tip/tilt of the screen, which in turn gives the relative distortion coefficient. We present experimental results to demonstrate the utility of the method by comparing our results with the corresponding values determined by open source software available online. © 2012 Optical Society of America.

Hwang K.,Inha University
The Journal of craniofacial surgery | Year: 2010

The aim of this study was to elucidate the width and length of the superior palpebral muscle by using anti-α-smooth muscle actin antibody. Ten orbits of 5 adult Korean cadavers were used. Eyelids were cut in vertical planes through midpupilliary, medial limbus, and lateral limbus and in horizontal planes at the anterior border of the superior transverse ligament and 2 mm proximal to the upper tarsal border. Superior palpebral muscle was localized using mouse monoclonal anti-α-smooth muscle actin and counterstained with light green for collagen. In enlarged pictures of sections, widths, lengths, and thicknesses of the superior palpebral involuntary muscle were measured with a curved scale and were analyzed. The levator palpebrae superioris muscle was divided into superficial and deep parts below the superior transverse ligament. The levator aponeurosis originated from the superficial part and the superior palpebral muscle originated from the deep part of the levator palpebrae superioris muscle. The aponeurosis was inserted into the upper border of tarsus. The superior palpebral muscle fibers arose 2.71 ± 0.64 mm posterior to the anterior border of the superior transverse ligament. The superior palpebral muscle was trapezoidal. The lengths of its sides were 15.58 ± 1.82 and 22.30 ± 5.25 mm, and its height was 13.70 ± 2.74 mm. The levator aponeurosis covered the superior palpebral muscle anteriorly. The width of the levator aponeurosis was approximately 4 mm wider than the superior palpebral muscle. The thicknesses of the superior palpebral muscle were 0.14 ± 0.13 mm at the anterior border of the superior transverse ligament, 0.45 ± 0.11 mm at the superior fornix level, and 0.10 ± 0.03 mm at the upper border of the tarsal plate. One vascular layer was between the levator aponeurosis and the superior palpebral muscle (upper vascular layer), and the other was between the superior palpebral muscle and the conjunctiva (lower vascular layer). At the superior fornix level, thickness of the upper and lower vascular layers was 0.28 ± 0.06 and 0.38 ± 0.21 mm, respectively. The result of our study might contribute to corrective blepharoptosis surgery.

Oh H.,Inha University
Orthopaedic nursing / National Association of Orthopaedic Nurses | Year: 2011

This study was conducted to develop a web-based gout self-management program that can be applicable to each gout stage and to evaluate the validity of the developed program. A web-based gout self-management program was developed and evaluated in 5 stages: analysis (needs assessment on 60 gout patients and content analysis through a systematic review of literature and websites), design, development, implementation, and evaluation. The gout-related information section was structured with overview, causes, risk factors, symptoms, diagnosis, progress, treatments, and complications. The self-management section consisted of diet/nutrition, weight control, alcohol management, exercise, and pain and stress management. The program included bulletin board and expert section to promote bidirectional interactions between program users and providers. Self-assessment tool of gout stages and self-management checklist were provided. Program contents and ease of site navigation (http://goutin.kr) were found to be appropriate and satisfactory to both patient and expert groups.

Sankar D.S.,Universiti Sains Malaysia | Lee U.,Inha University
Journal of Mechanical Science and Technology | Year: 2011

A computational model is developed to analyze the effects of magnetic field in a pulsatile flow of blood through narrow arteries with mild stenosis, treating blood as Casson fluid model. Finite difference method is employed to solve the simplified nonlinear partial differential equation and an explicit finite difference scheme is obtained for velocity and subsequently the finite difference formula for the flow rate, skin friction and longitudinal impedance are also derived. The effects of various parameters associated with this flow problem such as stenosis height, yield stress, magnetic field and amplitude of the pressure gradient on the physiologically important flow quantities namely velocity distribution, flow rate, skin friction and longitudinal impedance to flow are analyzed by plotting the graphs for the variation of these flow quantities for different values of the aforesaid parameters. It is found that the velocity and flow rate decrease with the increase of the Hartmann number and the reverse behavior is noticed for the wall shear stress and longitudinal impedance of the flow. It is noted that flow rate increases and skin friction decreases with the increase of the pressure gradient. It is also observed that the skin friction and longitudinal impedance increase with the increase of the amplitude parameter of the artery radius. It is also found that the skin friction and longitudinal impedance increases with the increase of the stenosis depth. It is recorded that the estimates of the increase in the skin friction and longitudinal impedance to flow increase considerably with the increase of the Hartmann number. © 2011 The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg.

Kim S.,Inha University
Journal of Geometry and Physics | Year: 2010

Let (M, g) be a noncompact complete Bach-flat manifold with positive Yamabe constant. We prove that (M, g) is flat if (M, g) has zero scalar curvature and sufficiently small L2 bound of curvature tensor. When (M, g) has nonconstant scalar curvature, we prove that (M, g) is conformal to the flat space if (M, g) has sufficiently small L2 bound of curvature tensor and L4 / 3 bound of scalar curvature. © 2010 Elsevier B.V. All rights reserved.

Ham B.S.,Inha University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

To overcome the fundamental limitations of the π optical pulse-induced population inversion and optical decay-caused short storage time in conventional photon echoes, a coherent control of collective atoms is studied for inversion-free, optical decay-halted photon echoes, where the constraint of photon storage time is now replaced by a spin population decay process. Using phase-controlled double rephasing, an inversion-free photon echo scheme is obtained, where no spontaneous or stimulated emission-driven quantum noise exists. Thus, the present method can be applied for ultralong quantum memories in quantum repeaters for long-distance quantum communications. © 2012 American Physical Society.

You C.-Y.,Inha University
Journal of Applied Physics | Year: 2010

The critical current density for spin transfer torque switching with composite free layer structures is investigated using the macrospin Landau-Lifshitz-Gilbert equation. We consider a magnetic tunneling junction with a rigid fixed layer, and a composite free layer consisting of two coupled ferromagnetic layers in which the coupling is parallel or antiparallel. The dependence of critical current density on thickness, coupling sign and strength, spin torque efficiency, and magnetization of the composite free layer is explored. We determine that reduction in the critical current density can be achieved only through careful design of the composite free layer structures. We show the detailed spin dynamics of the composite free layer when the reduction in the critical current density is accomplished. © 2010 American Institute of Physics.

Oh M.,Pusan National University | Park S.-J.,Inha University | Jung Y.,Korea University of Technology and Education | Kim S.,Pusan National University
Synthetic Metals | Year: 2012

Polyaniline (PANI)/titanium dioxide (TiO 2) composites were prepared by a chemical oxidation polymerization. The composites were prepared with various amount of TiO 2 to find a relation between electrochemical properties of composites and compositions of TiO 2 and PANI in the composites. PANI/TiO 2 composites which had PANI as a shell and TiO 2 as a core part of the composites were successfully synthesized. Fiber-like PANI was also observed within the composites. The synthesis was explained as two stages of polymerization. First stage is a polymerization reaction occurred by a strong oxidative potential of TiO 2. Second stage is started by adding ammonium peroxydisulfate in reaction solution. Diameters of aggregations of the composites increased with the added amounts of TiO 2. The composite prepared with 10 wt.% of TiO 2 per aniline monomer weight showed the highest capacitance of 784 F g -1 among the prepared composites. But the composites prepared with excess amounts of TiO 2 showed lower capacitance than the highest one. The lower capacitances of the composites prepared with excess amounts of TiO 2 was considered as related with the diameters of the aggregations. The composites prepared with excess amounts of TiO 2 had large diameters for the aggregations. The TiO 2 particles in the core of composites that had large diameter are hard to participate in electrochemical reaction due to a long pathway from electrolyte to TiO 2 core and a blocking effect by outer TiO 2 particles. © 2012 Elsevier B.V. All rights reserved.

Shin B.,Sejong University | Won J.,Sejong University | Son T.,Hanyang University | Kang Y.S.,Hanyang University | Kim C.K.,Inha University
Chemical Communications | Year: 2011

The short circuit current of dye sensitised solar cells increased significantly by the simple addition of polyester hydroxyl acetylene bis(hydroxymethyl)propanoic acid dendrons on TiO2 nanoparticles, resulting in a very high overall energy conversion efficiency. © 2011 The Royal Society of Chemistry.

You C.-Y.,Inha University
Journal of Magnetics | Year: 2012

We investigate spin transfer torque (STT) in magnetic multilayer structures using micromagnetic simulations. We implement the STT contribution for magnetic multilayer structures in addition to the Landau-Lifshitz-Gilbert (LLG) micromagnetic simulators. In addition to the Sloncewski STT term, the zero, first, and second order field-like terms are also considered as well as the effects of the Oersted field due to the running current are addressed. We determine the switching current densities of the free layer with the exchange biased synthetic ferrimagnetic reference layers for various cases. © 2012 Journal of Magnetics.

Newby C.,Cornell University | Lee J.-K.,Inha University | Ober C.K.,Cornell University
Journal of Materials Chemistry C | Year: 2013

With the rise of functional printing there is a need to understand the inkjet printability of a greater range of materials. Fluorinated materials and solvents have some unusual properties but this study finds them to be reliably inkjet printable. The fluorinated ink used has Reynolds and Weber numbers of 9.2 ± 1.8 and 20.3 ± 3.0, respectively. Printed line widths on silicon can be varied from 45 μm to 90 μm by adjusting printing parameters. A key advantage of printing from fluorinated solvents is that they can be printed on other organic layers without damaging or dissolving the underlayer. Test patterns are demonstrated on PMMA, P3HT, pentacene and F8BT. This naturally suggests their application to patterning organic semiconductors by selectively protecting some areas. The utility of this technique is demonstrated in the fabrication of an array of P3HT transistors with 2 μm channel lengths in which the active area is patterned using an inkjet printed single-drop fluoropolymer etch mask. This journal is © 2013 The Royal Society of Chemistry.

Shin H.,Inha University | Zeng J.,University of Lyon
European Journal of Combinatorics | Year: 2012

This paper was motivated by a conjecture of Brändén [P. Brändén, Actions on permutations and unimodality of descent polynomials, European J. Combin. 29 (2) (2008) 514-531] about the divisibility of the coefficients in an expansion of generalized Eulerian polynomials, which implies the symmetric and unimodal property of the Eulerian numbers. We show that such a formula with the conjectured property can be derived from the combinatorial theory of continued fractions. We also discuss an analogous expansion for the corresponding formula for derangements and prove a (p, q)-analogue of the fact that the (-1)-evaluation of the enumerator polynomials of permutations (resp. derangements) by the number of excedances gives rise to tangent numbers (resp. secant numbers). The (p, q)-analogue unifies and generalizes our recent results [H. Shin, J. Zeng, The q-tangent and q-secant numbers via continued fractions, European J. Combin. 31 (7) (2010) 1689-1705] and that of Josuat-Vergès [M. Josuat-Vergés, A q-enumeration of alternating permutations, European J. Combin. 31 (7) (2010) 1892-1906]. © 2011 Elsevier Ltd.

Membrane separations are powerful tools for various applications, including wastewater treatment and the removal of contaminants from drinking water. The performance of membranes is mainly limited by material properties. Recently, successful attempts have been made to add nanoparticles or nanotubes to polymers in membrane synthesis, with particle sizes ranging from 4 nm up to 100 nm. Ceramic membranes have been fabricated with catalytic nanoparticles for synergistic effects on the membrane performance. Breakthrough effects that have been reported in the field of water and wastewater treatment include fouling mitigation, improvement of permeate quality and flux enhancement. Nano-materials that have been used include titania, alumina, silica, silver and many others. This paper reviews the role of engineered nanomaterials in (pressure driven) membrane technology for water treatment, to be applied in drinking water production and wastewater recycling. Benefits and drawbacks are described, which should be taken into account in further studies on potential risks related to release of nanoparticles into the environment. © 2010 Elsevier Ltd.

Lee H.-I.,Inha University
Photonics and Nanostructures - Fundamentals and Applications | Year: 2010

Loss-induced optical Bloch waves are investigated in a metal-dielectric semi-infinite multilayer placed over a substrate. In addition to the well-known classification of the electromagnetic waves into forward and backward waves, the electrostatics-based sub-classification elucidates one-level finer details of the wave nature. For this purpose, a hypothetical process is devised by continuously varying the signal velocity. As a result, a given electromagnetic wave turns out to be related to a certain electrostatic state. By this way, the metal's material loss is found to play an essential role in inducing depthwise energy flows, although it has the usual detrimental role in wave attenuation. Depending on the wave direction, normal and inverted reflection peaks on resonant excitations are illustrated. © 2010 Elsevier B.V. All rights reserved.

Lee K.S.,Hanyang University | Han S.E.,Inha University | Park T.,Hanyang University
Computers and Structures | Year: 2011

The explicit arc-length method is simulated to trace the post-buckling equilibrium path of structures by using dynamic relaxation method with kinetic damping. This method based on the cylindrical arc-length method does not require the computation and formulation of any tangent stiffness matrix to search the snap-through or snap-back problems. The convergence to the solution is achieved by using only vector equation with kinetic damping technique. Two approaches for cylindrical arc-length control are formulated with incremental and total displacement constraint. The merits of the explicit arc-length method, in tracing the post-buckling behavior of structures, are demonstrated by analyzing the numerical examples. © 2010 Elsevier Ltd. All rights reserved.

Kim K.J.,Inha University | Tsiftsis T.A.,Technological Educational Institute of Lamia
IEEE Transactions on Vehicular Technology | Year: 2011

The maximum average achievable rate and the outage probability of the opportunistic scheduling over the cyclically prefixed (CP) single-carrier (SC) downlink transmissions are analyzed. In the user terminal, the QR-decomposition (QRD)-based receiver is employed to maintain the multipath diversity gain. Based on the proposed receiver, closed-form expressions for the maximum average achievable rate and the outage probability can be derived using the property of the circulant matrix. In addition, the outage diversity gain is obtained at high average signal-to-noise ratio (SNR). Simulations verified the derived analysis. © 2010 IEEE.

Tongzon J.,Inha University
International Journal of Logistics Research and Applications | Year: 2011

No in-depth region-wide analysis has yet been undertaken to assess progress made since the countries of the Association of Southeast Asian Nations (ASEAN) agreed to liberalise their logistics services in line with their vision to establish anASEAN Economic Community. In this light, this paper discusses the motivation behind their decision to liberalise their logistics sector, assesses the progress of implementation of their liberalisation commitments and identifies the underlying factors that have hindered or are likely to affect their ability to implement them. The ASEAN countries differ significantly in terms of the strength of their logistics industries and the adequacy of their institutional and regulatory/legal frameworks. Due to these significant differences, these countries are faced with major constraints. These constraints and possibilities for facilitating the liberalisation of their logistics services are examined. Possibilities include effective implementation of trade facilitation measures, liberalisation within sub-regional grouping and a staged framework of liberalisation. © 2011 Taylor & Francis.

To expand the applications of positron emission tomography (PET), novel specific radiopharmaceuticals using positron-emitters, such as fluorine-18 (F-18, t1/2 = 109.8 min), will be needed. Recently, strain-promoted alkyne azide cycloaddition (SPAAC) has been considered as an alternative bioorthogonal conjugation reaction between bioactive molecules and radiolabeled building blocks for the synthesis of novel radiopharmaceuticals. This mini-review provides a rapid overview of the emerging synthetic strategies based on the copper-free SPAAC conjugation reaction under physiologically-friendly reaction conditions for the high-throughput synthesis of 18F-labeled peptide tracers. Furthermore, an efficient mesoporous silica nanoparticles (MSNs) pretargeting for PET imaging were also introduced through the in situ bioorthogonal SPAAC labeling reaction by forming 18F-labeled MSNs at the tumor site in a living specimen. © 2015 Elsevier B.V.All rights reserved.

Song C.Y.,Mokpo National University | Lee J.,Yonsei University | Mo Choung J.,Inha University
Ocean Engineering | Year: 2011

The paper deals with the reliability-based design optimization (RBDO) of a riser support installed on a floating production storage and offloading (FPSO) unit under operation, extreme, damaged, and one line failure cases and installation loading conditions. The optimization problem is formulated such that probabilistic thickness variables described with random characteristics are determined by minimizing the weight of the riser support structure subjected to stress constraints for the given target reliability. The initial design model is generated based on actual FPSO riser support specifications. The finite element analysis is conducted using NASTRAN, and the probabilistic optimal solutions are obtained via the moving least squares method in the context of RBDO using a response surface meta-model. For the meta-modeling of the inequality constraint functions of stresses, a constraint-feasible moving least squares method (CF-MLSM) is adopted in the present study. The CF-MLSM has been shown to ensure constraint feasibility regardless of the nonlinearity of the constraint function, the feasible bounds, and the random characteristics during the meta-model-based RBDO process. The solution results from the proposed RBDO strategy present improved design performances under various riser operating conditions. © 2010 Elsevier Ltd. All rights reserved.

Ochiai S.,Aichi Institute of Technology | Kumar P.,Aichi Institute of Technology | Santhakumar K.,Aichi Institute of Technology | Shin P.-K.,Inha University
Electronic Materials Letters | Year: 2013

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), a conducting polymer, has been receiving a great deal of attention for next generation optoelectronic organic devices. In this report, we discuss the effect of additives along with the thickness of PEDOT:PSS layers on the power conversion efficiency of organic solar cell devices. PEDOT:PSS films treated with high boiling point solvents of dimethyl sulfoxide (DMSO) and ethylene glycol (EG) show a significant enhancement in electrical conductivity without compromising flexibility or optical transparency. The conductivity increased from 0.5 to 517 and 724 S/cm after once and thrice treatment with 4 vol. % EG, respectively. The as-prepared and additives-treated PEDOT:PSS films deposited on glass substrates have been investigated by optical spectroscopy, micro-Raman spectroscopy and atomic force microscopy (AFM). The results indicate that structural and morphological changes were induced by the additive processes. By using DMSO and EG treated PEDOT:PSS as a hole transport layer, organic solar cells with a Poly[[9-(1-octylnonyl)-9H-carbazole-2,7-diyl]-2,5-thiophenediyl-2,1,3-benzothiadiazole-4,7-diyl-2,5-thiophenediyl]:[6,6]-phenyl-C71-butyric acid methyl esters (PCDTBT:PC71BM) bulk heterojunction have been fabricated on indium-tin-oxide (ITO) coated glass substrates. The high power conversion efficiency (PCE) of 5.17%, and 5.69%, were observed for PEDOT:PSS hole transport layers treated with DMSO and EG respectively, even though the devices were prepared in air atmosphere. © 2013 The Korean Institute of Metals and Materials and Springer Science+Business Media Dordrecht.

Cardiomyocytes contain secretory granules in which chromogranins and several types of natriuretic peptides and growth factors are stored in addition to high Ca2+ concentrations. Yet the expression and serum levels of chromogranins and natriuretic peptides have been closely correlated with pathological cardiac hypertrophy and heart failure. Moreover, in distinction from the physiological cardiac hypertrophy that appears not to involve inositol 1,4,5-trisphosphate (IP3) production as the primary signaling step, accumulating evidence underscores the central role of IP3-induced intracellular Ca 2+ releases in cardiomyocytes in the development of pathological cardiac hypertrophy. Consistent with this observation, chronic treatment of cardiomyocytes with G-protein coupled receptor agonists endothelin-1, angiotensin II, or phenylephrine, agents that are known to produce intracellular IP3, leads to cardiomyopathy and heart failure. In particular, the IP3-induced Ca2+ release inside the nucleus has been suggested to initiate a series of nuclear activities, including 1) Ca2+-calmodulin (CaM) mediated protein kinase II (CaMKII) activation, 2) activation of transcription factors such as myocyte enhancer factor-2 (MEF-2) and nuclear factor -B (NF-B), and 3) increased production of chromogranins, natriuretic peptides, and growth factors, which eventually lead to pathological hypertrophy. Although secretory granules function as the major IP3-sensitive intracellular Ca2+ store and the IP3-mediated Ca2+ release from secretory granules in cardiomyocytes contributes to secretion of chromogranins and natriuretic peptides, the direct cause of pathological hypertrophy appears to be due to the IP3-induced Ca2+ release from the small nucleoplasmic IP3-sensitive Ca2+ store vesicles, thereby initiating the Ca2+-activated nuclear activities that lead to formation of more secretory granules, pathologic enlargement of cardiomyocytes, and heart failure. © 2012 Bentham Science Publishers.

Fan J.,Nanjing Forestry University | Li F.,Nanjing University | Nakamura G.,Inha University
Zeitschrift fur Angewandte Mathematik und Physik | Year: 2015

We prove the global-in-time and uniform-in-(ϵ1,ϵ2) of strong solutions to the isentropic Navier–Stokes–Maxwell system in a bounded domain, when ϵ1 is the Mach number, and ϵ2 is the dielectric constant. Consequently, we obtain the convergences of compressible Navier–Stokes–Maxwell system to the incompressible Navier–Stokes–Maxwell system (Formula Presented.), the compressible magnetohydrodynamic equations (Formula Presented.) or the incompressible magnetohydrodynamic equations (Formula Presented.) for well-prepared data. © 2014, Springer Basel.

Kim S.,University of Minnesota | Sobelman G.E.,University of Minnesota | Lee H.,Inha University
IEEE Transactions on Very Large Scale Integration (VLSI) Systems | Year: 2011

A reduced-complexity low density parity check (LDPC) layered decoding architecture is proposed using an offset permutation scheme in the switch networks. This method requires only one shuffle network, rather than the two shuffle networks which are used in conventional designs. In addition, we use a block parallel decoding scheme by suitably mapping between required memory banks and processing units in order to increase the decoding throughput. The proposed architecture is realized for a 672-bit, rate-1/2 irregular LDPC code on a Xilinx Virtex-4 FPGA device. The design achieves an information throughput of 822 Mb/s at a clock speed of 335 MHz with a maximum of 8 iterations. © 2010 IEEE.

Park D.,Inha University
IEEE Communications Letters | Year: 2011

In this paper, we propose regularized vector perturbation in MIMO two-way relay channels in order to align phases of received signals. The proposed scheme not only simplifies the detection process at the relay, but also removes the perturbation vector without its knowledge. Numerical results show that the proposed scheme improves the block error performance. © 2010 IEEE.

This paper presents a fast block-matching algorithm based on the normalized cross-correlation, where the elimination order is determined based on the gradient magnitudes of subblocks in the current macroblock. Multilevel Cauchy-Schwartz inequality is derived to skip unnecessary block-matching calculations in the proposed algorithm. Also, additional complexity reduction is achieved re-using the normalized cross correlation values for the spatially neighboring macroblock because the search areas of adjacent macroblocks are overlapped. Simulation results show that the proposed algorithm can improve the speed-up ratio up to about 3 times in comparison with the existing algorithm. © 2011 ETRI.

We find a noticeable reduction of the spin transfer torque switching current density in a lateral symmetry breaking structure by employing micromagnetic simulation. We investigate the detailed spin dynamics in a conventional magnetic tunneling junction structure with an ellipse shape; the switching occurs with incoherent spin rotation by forming irregular spin configurations. By introducing the proper asymmetry of the lateral shape of a magnetic tunneling junction, a more efficient coherent spin rotation mode is easily excited and the switching current density shows a 30-40% reduction. © 2013 The Japan Society of Applied Physics.

Shi L.,University of California at Davis | Mukherjee B.,University of California at Davis | Lee S.-S.,Inha University | Lee S.-S.,Electronics and Telecommunications Research Institute | Lee S.-S.,Korean University of Science and Technology
IEEE Network | Year: 2012

Energy usage in our networks is increasing rapidly; and to conserve energy, progress has been made in designing energy-efficient passive optical networks, which are being widely deployed for broadband access. Among the various energy-saving techniques, enabling sleep mode in optical network units is a very promising approach. However, the slow transition of power from active mode to sleep mode in an optical network unit, and the relatively large recovery and synchronization time needed during the wakeup process are challenges that need to be addressed. In this regard, we propose a service-level-agreement-based scheduling scheme for passive optical networks in which the optical line terminal can adjust the sleep time and the optical network unit can quit sleep mode for sending high-priority packets. The trade-off in energy savings vs. delay performance is evaluated using simulations under practical power consumption settings. © 2012 IEEE.

Lee J.W.,Hyundai E and C Co. | Jung H.J.,KAIST | Park J.Y.,Inha University | Lee J.B.,POSCO | Yoon Y.,KAIST
Renewable Energy | Year: 2013

This paper presents and optimizes the annual heating, cooling and lighting energy consumption associated with applying different types and properties of window systems in a building envelope. Through using building simulation modeling, various window properties such as U-value, solar heat gain coefficient (SHGC), and visible transmittance (Tvis) are evaluated with different window wall ratios (WWRs) and orientations in five typical Asian climates: Manila, Taipei, Shanghai, Seoul and Sapporo. By means of a regression analysis, simple charts for the relationship between window properties and building energy performance are presented as a function of U-value, SHGC, Tvis, WWR, solar aperture, effective aperture, and orientation. As a design guideline in selecting energy saving windows, an optimized window system for each climate is plotted in detailed charts and tables. © 2012 Elsevier Ltd.

Cho J.H.,Dankook University | Cho M.-W.,Inha University
IEEE Transactions on Instrumentation and Measurement | Year: 2013

Wireless position tracking systems can be used in applications, such as mobiles, robot tracking systems, and Internet location-based service (LBS) applications. The GPS system is the best-known position tracking system for use in outdoor locations through satellite tracking systems. Cost-effective radio frequency identification (RFID) tracking methods for indoor systems have also been developed. However, most of these systems use active RFID tags that use expendable batteries. We develop a low-cost indoor position tracking system that uses passive RFID. The proposed indoor tracking system, using a precise tracking algorithm, is applied to various locations. The system is tested by validating the signal-to-noise level caused by errors. B-spline surfaces generated by an approximation formula are used as baseline data. This proposed system can also be applied to mobile robot systems, automated guided vehicles (AGVs), and phone LBSs. © 1963-2012 IEEE.

Han S.,Inha University
Journal of Asian Architecture and Building Engineering | Year: 2010

Researchers and site engineers in construction have tried to develop appropriate methods of productivity measurements. Even though many methods have been released in academia and industry, they seldom are able to select the optimized method while considering various site conditions. This study was developed from a previous study which presented the quantified productivity differences on one specific operation, that of the conventional earthmoving operation. This study suggested more consistent results for productivity differences by various methods while focusing on two different operations; the conventional and the GPS-based system. This study verified the findings from a previous study whereby results from a deterministic method and an actual measurement yield the highest values and the lowest values, respectively. It was also found that the quantified differences were mostly within 10% of the range of productivity loss in the deterministic measurement, which was illustrated in the literature. Additional statistical verification showed that the differences were mostly within 95% of the confidence intervals. It is expected that this study will provide researchers in academia with basic guidelines for developing appropriate methods for performance measurements. This study also assists site engineers in the construction industry to predict productivity and to convert results to more realistic values by using methods other than actual measurements.

Ham B.S.,Inha University
Journal of the Optical Society of America B: Optical Physics | Year: 2012

Unlike slow-light-based quantum memories, photon echoes offer the benefit of high speed and wide bandwidth. Over the last decade, the rephasing mechanism of photon echoes has been studied for quantum memories to overcome fundamental limitations in photon echoes, such as population inversion and low retrieval efficiency. Although these limitations have been overcome in modified photon echo schemes, photon storage time is still too short to apply it to long-distance quantum communications. For long-distance quantum communications, ultralong photon storage time of the order of seconds is needed to implement quantum repeaters. In this review article, challenging techniques for ultralong photon storage are presented, where ultralong storage is obtained via a coherence conversion process between optical and spin states by using an optical locking technique. To remove population-inversion-caused quantum noise, a double rephasing scheme is addressed, where rephasingpulse-caused population inversion hinders photon echoes for quantum memory applications. © 2012 Optical Society of America.

Using on-demand coherence conversion via optical locking, a dynamic coherent control of the collective atom phase has been demonstrated for longer photon storage beyond the critical constraint of spin phase decay time, where the storage time can be extended up to hours in a rare-earth-doped solid. Coherent transient phenomena such as photon echoes have been investigated for frozen phase decay via coherent population transfer using a simple deshelving optical pulse pair. Unlike the rephasing halt applied to two-pulse photon echoes, where optical decoherence is accelerated by spin inhomogeneous broadening, a completely atom phase-locked coherence conversion has been observed in three-pulse photon echoes, resulting in spin dephasing-free coherence control. Here, the mechanism of the atom phase-locked coherence conversion via optical locking has been investigated in a solid medium whose optical transition is imperfect, where partial coherence is lost via optical depth-dependent imperfect population transfer. The relationship between coherence loss and optical depth is analyzed, where nearly perfect photon echo efficiency can be obtained for ultralong photon storage in an optically thick medium. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.

Kim N.R.,Inha University
Korean journal of ophthalmology : KJO | Year: 2010

A 60-year-old woman who had experienced two episodes of amaurosis fugax in her right eye presented with vision loss. Two weeks earlier, at a private clinic, she was diagnosed with impending central retinal vein occlusion (CRVO) of the right eye and received an intravitreal injection of bevacizumab. Two weeks after this injection she was diagnosed with ischemic CRVO. At 11-weeks post-presentation, extremely ischemic features were observed with fluorescein angiographic findings of severe vascular attenuation and extensive retinal capillary obliteration. At 22-weeks post-presentation she was diagnosed with neovascular glaucoma; she experienced no visual improvement over the following several months.

Hwang K.,Inha University
Journal of Craniofacial Surgery | Year: 2014

The aim of this review was to familiarize the reader with critical facial nerve anatomy relating to facial rejuvenation surgeries.The temporal branch to the upper orbicularis oculi muscle (OOM): The temporal branch was under the temporoparietal fascia above the zygomatic arch and divided into 2 to 4 branches. The highest level of the twigs that entered the OOM on the x axis and the y axis with the origin of the lateral canthus is +2.51 ± 0.23 cm and +2.70 ± 0.35 cm; and the lowest, 0 cm and +2.68 ± 0.32 cm, respectively. The zygomatic and the buccal branch to the lower OOM: All pretarsal and preseptal OOMs were innervated by 5 to 7 terminal twigs of the zygomatic branches of the facial nerve that approached the muscle at a right angle. The medial portion of the lower OOM was innervated by 1 to 2 terminal twigs of the buccal branch, and the middle portion was innervated with 2 to 3 twigs of the zygomatic branch. The lateral portion was supplied by the uppermost zygomatic branch, which split into 2 to 4 twigs. The temporal branch to the corrugator supercilii muscle: A plexus mainly from the inferior ramus partly from the middle ramus of the temporal branch of the facial nerve enters the corrugator supercilii muscle in the supraorbital area. The temporal branch has as many as 4 to 7 rami, with interconnection among them. The buccal branch to the procerus muscle: The buccal branch crosses the intercanthal line (the nasion to the medial canthus) at approximately one third laterally. The nerve entrance was within a circle with a diameter of 5 mm, and its center was located 9 mm lateral and 10 mm superior from the nasion. It was approximately at the midpoint of the lateral half of the intercanthal line and the lower one third between the intercanthal line and the tangential line of the supraorbital rim. The buccal branch, the buccal fat pad, and the parotid duct: The buccal branches and the parotid duct crossed each other within a semicircle with a 30-mm radius. The base (diameter) was parallel to a horizontal line passing the corner of the mouth and 12 mm above. Its center was located 53 mm lateral to it. The buccal branches of the facial nerve have 2 locations at the buccal fat pad: type I, branches crossing superficial to the buccal fat pad in 14 (73.7%) of 19 specimens, and type II, 2 twigs passing through the buccal extension of the buccal fat pad in 5 (26.3%) of 19 specimens. The buccal branch to the upper orbicularis oris muscle: Approximately 4 branches (4.06 ± 0.83) entering the pars marginalis were found. Most ramifying points (14/17, 82%) were located within a circle with a 5-mm radius, and the center was 12 mm lateral and 26 mm superior to the mouth corner. The mandibular branch according to the neck position: At the one-fourth point, the border-nerve distance decreased (4.32 ± 2.60 mm) with the neck in ipsilateral rotation and the border-nerve distance increased (5.97 ± 2.62 mm) with the neck in contralateral rotation.We hope that this knowledge will aid surgeons in achieving successful outcomes. © 2014 Mutaz B. Habal, MD.

Lee Y.-G.,Inha University
Scientometrics | Year: 2012

The era of open and sustainable innovation has opened and requested new kinds of human resources (HRs) development at Korean universities. Typical academic and vocational education at universities does not effectively work in the age of technological convergence and open innovation. Knowledge and skills for Green growth and rapid technological innovation demand very skilful, broad, and complex competencies of HRs. Competencies for green growth and disruptive innovation are outlined and various methods to increase competencies at Korean universities are suggested in this study. This study explores the kinds of competencies for future society and suggests how university can contribute to cultivate talents for HRs with multi-functional and high competencies. The author takes a sketch of competence and skill structure in Korea, summarized in value chain of competencies among HRs with high competencies, HRs with medium competencies, and HRs with low competencies. Particularly the author addresses innovation oriented fields such as engineering and chemistry/pharmaceuticals, therefore, the picture can be different from typical manufacturing sectors such as automobile and shipbuilding. However, the manufacturing fields are also progressing into innovation centred sectors. And then the author explores the flow of each HRs according to levels and fields and how they affect Korean innovation system. © 2011 Akadémiai Kiadó, Budapest, Hungary.

Jeong S.-H.,Inha University | Elnashai A.S.,University of Illinois at Urbana - Champaign
Structure and Infrastructure Engineering | Year: 2012

It is desirable to use probabilistic performance targets for decision-making as it relates to intervention methods, because of high uncertainties of structure responses under earthquake loadings. This is based on the probabilistic performance assessment of structures with various retrofit options. Extensive computer simulations to account for the randomness in both input motion and response characteristics have been a serious obstacle to the adoption of the probabilistic performance assessment in the decision of seismic intervention schemes. This study presents an approach whereby a fragility assessment result with known reliability is derived based on the fundamental response quantities of stiffness, strength and ductility. An exact solution for a generalised single-degree-of-freedom system is employed to construct a response database of maximum responses. Once the fundamental response quantities of a wide range of structural systems are defined, the fragility assessment for various limit states can be constructed without recourse to further simulation. By virtue of its instantaneous nature, the proposed method is especially useful for practical application of the analytical fragility assessment that includes the planning of seismic rehabilitation and regional earthquake mitigation, where fast estimation of probabilities of reaching damage states for a large number of structural configurations and different mitigation measures is required. For cases of selection between different retrofitting options, the proposed approach gives rapid estimates of probabilities of various damage levels inflicted on the structures under consideration, given only the stiffness, strength and ductility for each alternative retrofitting scheme. The presented fragility contour and constant fragility spectra enable the engineer to use visualised data sets to practically and conveniently investigate the probabilistic performance of every retrofit option. © 2012 Copyright Taylor and Francis Group, LLC.

Liu J.,Xidian University | Zhang Z.,Orange S.A. | Chen X.,Xidian University | Kwak K.S.,Inha University
IEEE Transactions on Parallel and Distributed Systems | Year: 2014

Wireless body area network (WBAN) has been recognized as one of the promising wireless sensor technologies for improving healthcare service, thanks to its capability of seamlessly and continuously exchanging medical information in real time. However, the lack of a clear in-depth defense line in such a new networking paradigm would make its potential users worry about the leakage of their private information, especially to those unauthenticated or even malicious adversaries. In this paper, we present a pair of efficient and light-weight authentication protocols to enable remote WBAN users to anonymously enjoy healthcare service. In particular, our authentication protocols are rooted with a novel certificateless signature (CLS) scheme, which is computational, efficient, and provably secure against existential forgery on adaptively chosen message attack in the random oracle model. Also, our designs ensure that application or service providers have no privilege to disclose the real identities of users. Even the network manager, which serves as private key generator in the authentication protocols, is prevented from impersonating legitimate users. The performance of our designs is evaluated through both theoretic analysis and experimental simulations, and the comparative studies demonstrate that they outperform the existing schemes in terms of better trade-off between desirable security properties and computational overhead, nicely meeting the needs of WBANs. © 1990-2012 IEEE.

Na Y.,Inha University | Cho G.,Yonsei University
Fibers and Polymers | Year: 2010

Sound absorption property, viscoelastic property and the effect of plasma treatment of four automotive nonwoven fabrics on these properties are discussed in this research paper. Needle-punched fabrics used for vehicle headliner include 2 polyester fabrics made of hollow polyester fibers or solid polyester fibers, and 2 polypropylene-composite cellulose fabrics made of jute fibers or kenaf fibers, manufactured with the same web structure of apparent fabric density and fabric thickness. Hollow polyester fiber fabric has the highest sound absorption and the highest loss factor, the second highest is jute fiber fabric. The viscoelastic property is found to be related to the sound absorption property of fabric. The plasma treatment on nonwoven fabrics changes their sound absorption and viscoelastic property as well as their fabric weight and pore size. Hollow polyester fabric shows the increased sound absorption and viscoelastic property after the treatment with the increased pore sizes, while regular polyester fabric displays insignificant changes. The cellulose fabrics are more affected by plasma treatment compared to the polyester fabrics in terms of fabric weight loss and pore size, and jute fabric is more affected than kenaf fabric due to fiber weakness. The jute fabric demonstrates the decreased sound absorption and viscoelastic property, while kenaf fabric shows the increased sound absorption with the unchanged viscoelastic property after the treatment. © 2010 The Korean Fiber Society and Springer Netherlands.

Lee H.-B.-R.,Stanford University | Baeck S.H.,Stanford University | Baeck S.H.,Inha University | Jaramillo T.F.,Stanford University | Bent S.F.,Stanford University
Nano Letters | Year: 2013

The formation of Pt nanowires (NWs) by atomic layer deposition on highly ordered pyrolytic graphite (HOPG) is investigated. Pt is deposited only at the step edges of HOPG and not on the basal planes, leading to the formation of laterally aligned Pt NWs. A growth model involving a morphological transition from 0-D to 1-D structures via coalescence is presented. The width of the NWs grows at a rate greater than twice the vertical growth rate. This asymmetry is ascribed to the wetting properties of Pt on HOPG as influenced by the formation of graphene oxide. A difference in Pt growth kinetics based on crystallographic orientation may also contribute. © 2013 American Chemical Society.

Kim B.S.,Inha University | Lee J.W.,Yonsei University
Techniques in Foot and Ankle Surgery | Year: 2010

Total ankle replacement for a varus unstable ankle is challenging but feasible. Clinical outcomes are satisfactory when the ankle is placed on a stable, plantigrade foot. The keys to successful replacement include optimal ligament balancing and correction of all associated deformities. Therefore, the surgeon must have a thorough understanding of the associated deformities and the appropriate surgical armamentarium to address them. Copyright © 2010 by Lippincott Williams & Wilkins.

Anbu P.,Inha University
Brazilian Journal of Medical and Biological Research | Year: 2016

A bacterial strain (PAP04) isolated from cattle farm soil was shown to produce an extracellular, solvent-stable protease. Sequence analysis using 16S rRNA showed that this strain was highly homologous (99%) to Brevibacillus laterosporus. Growth conditions that optimize protease production in this strain were determined as maltose (carbon source), skim milk (nitrogen source), pH 7.0, 40°C temperature, and 48 h incubation. Overall, conditions were optimized to yield a 5.91-fold higher production of protease compared to standard conditions. Furthermore, the stability of the enzyme in organic solvents was assessed by incubation for 2 weeks in solutions containing 50% concentration of various organic solvents. The enzyme retained activity in all tested solvents except ethanol; however, the protease activity was stimulated in benzene (74%) followed by acetone (63%) and chloroform (54.8%). In addition, the plate assay and zymography results also confirmed the stability of the PAP04 protease in various organic solvents. The organic solvent stability of this protease at high (50%) concentrations of solvents makes it an alternative catalyst for peptide synthesis in non-aqueous media. © 2016, Associacao Brasileira de Divulgacao Cientifica. All rights reserved.

Jung Y.,Inha University | Merwade V.,Purdue University
Hydrological Processes | Year: 2015

A need for more accurate flood inundation maps has recently arisen because of the increasing frequency and extremity of flood events. The accuracy of flood inundation maps is determined by the uncertainty propagated from all of the variables involved in the overall process of flood inundation modelling. Despite our advanced understanding of flood progression, it is impossible to eliminate the uncertainty because of the constraints involving cost, time, knowledge, and technology. Nevertheless, uncertainty analysis in flood inundation mapping can provide useful information for flood risk management. The twin objectives of this study were firstly to estimate the propagated uncertainty rates of key variables in flood inundation mapping by using the first-order approximation method and secondly to evaluate the relative sensitivities of the model variables by using the Hornberger-Spear-Young (HSY) method. Monte Carlo simulations using the Hydrologic Engineering Center's River Analysis System and triangle-based interpolation were performed to investigate the uncertainty arising from discharge, topography, and Manning's n in the East Fork of the White River near Seymour, Indiana, and in Strouds Creek in Orange County, North Carolina. We found that the uncertainty of a single variable is propagated differently to the flood inundation area depending on the effects of other variables in the overall process. The uncertainty was linearly/nonlinearly propagated corresponding to valley shapes of the reaches. In addition, the HSY sensitivity analysis revealed the topography of Seymour reach and the discharge of Strouds Creek to be major contributors to the change of flood inundation area. © 2014 John Wiley & Sons, Ltd.

Jeong B.-Y.,Korea Institute of Ceramic Engineering And Technology | Jung E.H.,Inha University
Metals and Materials International | Year: 2013

Niobium oxide produced by an anodization process for application in a high-efficiency dye-sensitized solar cell (DSSC) has been reported. In order to increase the energy conversion efficiency of the cell, we demonstrated niobium oxide micro-mountain and nano-forest pancake structures that contained nanowires on the surface. The increase in efficiency is attributed to the significantly enhanced surface area, which allows for more dye loading and light harvesting, as well as the reduced charge recombination, which provides direct conduction pathways along the crystalline Nb2O5 micro-mountain structures with nanowires. We observed that the photovoltaic performance of the Nb2O5 DSSC increased from 1.03% to 3.35% when the oxide thickness was increased from 9.3 μm to 27.7 μm. Since the anodization process is very cheap and takes place at low temperatures, it has substantial potential for the further development of DSSCs with metal-oxide nano-materials. Anodized oxide advantage is that essentially any form of a niobium surface can be treated in a quick and low-cost approach with Nb2O5 coating. © 2013 The Korean Institute of Metals and Materials and Springer Science+Business Media Dordrecht.

Beom H.G.,Inha University
European Journal of Mechanics, A/Solids | Year: 2013

A generalized two-dimensional deformation of an anisotropic elastic solid is considered. The transformed function method is employed to remove the breakdown limitation of the Stroh formalism for a degenerate anisotropic solid with multiple characteristic roots. The anisotropic elastic formalism for a general solution of elastic fields does not breakdown, and the closed form expressions of elastic fields for the degenerate anisotropic materials are obtained. A general solution of the thermoelastic fields in an anisotropic material under steady-state heat conduction is also derived. The thermoelastic formalism is shown to be valid for an anisotropic solid with distinct thermoelastic characteristic roots and a degenerate anisotropic solid with multiple thermoelastic characteristic roots. © 2013 Elsevier B.V.

Kang K.-S.,Inha University
Chemical Engineering Journal | Year: 2010

Uniform size, height and poreless micropattern fabrication on a flexible substrate becomes an important factor for electronic paper development. Recently, thin and flexible display has been a main target in display industry. Therefore, for the future industrial application, non-petroleum based and environmentally friendly thin and flexible micromold development is an essential technology for flexible display application. For this application, existence of micro or nanopores is drawback due to the reduction of transmittance by light scattering and leak of carrier solvent. The liquid-liquid demixing process made porous structure of the cellulose acetate (CA) film. The resulting CA films were optically turbid due to the light scattering by the pores. Single solvent process provides optically transparent and smooth surface films. Line, honeycomb, and square shapes of photoresist patterns were fabricated on the silicon wafer with different heights (2μm and 20μm). The replicas of the CA-patterns have about the same sizes and heights with respect to those of the photoresist patterns. The cross-sectional field emission scanning electron microscope images exhibit the pore-free CA mold. © 2010 Elsevier B.V.

Fan J.,Nanjing Forestry University | Jia X.,City University of Hong Kong