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Hsinchu, Taiwan

National Chiao Tung University , is a renowned public research university with international reputation located in Hsinchu City, Taiwan. NCTU was originally founded in Shanghai in 1896 and re-established in Taiwan by former Chiao Tung University faculty and alumni members in 1958, following the government of the Republic of China's forced relocation to Taiwan after the Chinese Civil War. The university's main campus is located close to the Hsinchu Science Park, Taiwan's national research center. The area is referred to as the Silicon Valley of Asia. More than 400 technology companies have been established in the park. The NCTU campus is also one of top tourist attractions in Hsinchu area. Wikipedia.

Chen W.-C.,National Chiao Tung University | Johnson A.L.,Texas A&M University
Computers and Operations Research | Year: 2010

Data envelopment analysis (DEA) uses extreme observations to identify superior performance, making it vulnerable to outliers. This paper develops a unified model to identify both efficient and inefficient outliers in DEA. Finding both types is important since many post analyses, after measuring efficiency, depend on the entire distribution of efficiency estimates. Thus, outliers that are distinguished by poor performance can significantly alter the results. Besides allowing the identification of outliers, the method described is consistent with a relaxed set of DEA axioms. Several examples demonstrate the need for identifying both efficient and inefficient outliers and the effectiveness of the proposed method. Applications of the model reveal that observations with low efficiency estimates are not necessarily outliers. In addition, a strategy to accelerate the computation is proposed that can apply to influential observation detection. © 2009 Elsevier Ltd. Source

Lin C.-S.,Kainan University | Liou F.-M.,Yuanpei University | Huang C.-P.,National Chiao Tung University
Applied Energy | Year: 2011

Among the various greenhouse gases associated with climate change, CO2 is the most frequently implicated in global warming. The latest data from Carbon Monitoring for Action (CARMA) shows that the coal-fired power plant in Taichung, Taiwan emitted 39.7 million tons of CO2 in 2007 - the highest of any power plant in the world. Based on statistics from Energy International Administration, the annual CO2 emissions in Taiwan have increased 42% from 1997 until 2006. Taiwan has limited natural resources and relies heavily on imports to meet its energy needs, and the government must take serious measures control energy consumption to reduce CO2 emissions. Because the latest data was from 2009, this study applied the grey forecasting model to estimate future CO2 emissions in Taiwan from 2010 until 2012. Forecasts of CO2 emissions in this study show that the average residual error of the GM(1,1) was below 10%. Overall, the GM(1,1) predicted further increases in CO2 emissions over the next 3 years. Although Taiwan is not a member of the United Nations and is not bound by the Kyoto Protocol, the findings of this study provide a valuable reference with which the Taiwanese government could formulate measures to reduce CO2 emissions by curbing the unnecessary the consumption of energy. © 2011 Elsevier Ltd. Source

Wang C.-C.,National Chiao Tung University
Energy Conversion and Management | Year: 2011

The present study examines the heat transfer coefficients applicable for membrane distillation. In the available literatures, researchers often adopt some existing correlations and claim the suitability of these correlations to their test data or models. Unfortunately this approach is quite limited and questionable. This is subject to the influences of boundary conditions, geometrical configurations, entry flow conditions, as well as some influences from spacer or support. The simple way is to obtain the heat transfer coefficients from experimentation. However there is no direct experimental data for heat transfer coefficients being reported directly from the measurements. The main reasons are from the uncertainty of permeate side and of the comparatively large magnitude of membrane resistance. Additional minor influence is the effect of mass transfer on the heat transfer performance. In practice, the mass transfer effect is negligible provided the feed side temperature is low. To increase the accuracy of the measured feed side heat transfer coefficient, it is proposed in this study to exploit a modified Wilson plot technique. Through this approach, one can eliminate the uncertainty from permeate side and reduce the uncertainty in membrane to obtain a more reliable heat transfer coefficients at feed side from the experimentation. © 2010 Elsevier Ltd. All rights reserved. Source

Wei C.C.,National Chi Nan University | Chen J.,National Chiao Tung University
Optics Express | Year: 2010

While coherency between an RF-tone and OFDM signals in RoF systems at 60 GHz is de-correlated by fiber dispersion, both phase rotation term (PRT) on each subcarrier and inter-carrier interference (ICI) between subcarriers are induced at a receiver. We analytically calculate the powers of PRT and ICI under different parameters, such as subcarrier number, modulation format, laser linewidth and transmission distance. Moreover, dispersion-induced ICI is shown to be non-Gaussian distributed by its kurtosis, and its distribution depends on system parameters. Therefore, using only the power of ICI cannot predict accurate bit error rate (BER) and corresponding power penalty. We propose to use t-distribution to fit the distribution of ICI, and it can be used to compute BER precisely. © 2010 Optical Society of America. Source

Pao H.-T.,National Chiao Tung University | Fu H.-C.,Huaqiao University
Energy Policy | Year: 2013

This study investigates the causal relationship between clean and non-clean energy consumption and economic growth in Brazil over the period of 1980-2009. Clean energy consumption at aggregated level of total renewable energy consumption and disaggregated levels of hydroelectric, new renewables, and nuclear energy consumption are tested within a production function framework. A cointegration test reveals a long-term equilibrium relationship between real output, capital, labor, and renewable and non-renewable energy consumption at aggregated level, and a long-term equilibrium relationship between real output, capital, labor, and hydroelectric/new renewables/nuclear and fossil fuel energy consumption at disaggregated level. The capital, labor, and new renewables elasticities of real output are positive and statistically significant, other energy consumption item's elasticities are insignificant. The results from error correction model reveal the interdependencies between new renewables, nuclear, fossil fuel, and total non-renewable energy consumption and economic growth, the unidirectional causality from hydroelectric/total renewable consumption to economic growth, the substitutability between new renewables and fossil fuel consumption, and the substitutability between new renewables and nuclear energy consumption. Additionally, nuclear and new renewables energy consumption responds to bring the system back to equilibrium. Overall, aggregated analysis may obscure the relationship between different types of clean energy consumption and economic growth. © 2013 Elsevier Ltd. Source

Chien C.-L.,Chung Yuan Christian University | Tsai W.-H.,National Chiao Tung University | Tsai W.-H.,Asia University, Taiwan
IEEE Transactions on Geoscience and Remote Sensing | Year: 2014

An image fusion method must ideally preserve both the detail of the panchromatic image and the color of the multispectral image. Existing image fusion methods incur the gamut problem of creating new colors which fall out of the RGB cube. These methods solve the problem by color clipping which yields undesirable color distortions and contrast reductions. An improved nonlinear IHS (intensity, hue, saturation; iNIHS) color space and related color transformations are proposed in this paper to solve the gamut problem without appealing to color clipping. The iNIHS space includes two halves, one being constructed from the lower half of the RGB cube by RGB to IHS transformations, and the other from the upper half of the RGB cube by CMY to IHS transformations. While incurring no out-of-gamut colors, desired intensity substitutions and additions in substitutive and additive image fusions, respectively, are all achievable, with the saturation component regulated within the maximum attainable range. Good experimental results show the feasibility of the proposed method. © 1980-2012 IEEE. Source

Lin C.-P.,National Chiao Tung University
Electronic Commerce Research and Applications | Year: 2011

This study validates a research model that examines usage of instant messaging (IM) from the aspect of online social support. Drawing on the social capital theory, this study postulates that IM usage is indirectly affected by social support via the mediation of the following six dimensions of social capital: commitment, reciprocity, shared codes and language, shared narratives, centrality, and network ties. The model tests data obtained from business organizations in Taiwan, and the results suggest that the indirect influence of social support on IM usage through shared codes and language is significant, and the indirect influence of social support on IM usage through centrality is also significant. Managerial implications and limitations of the empirical findings are provided. © 2010 Elsevier B.V. All rights reserved. Source

Liu Z.-H.,National Tsing Hua University | Chen J.-C.,National Chiao Tung University
IEEE Transactions on Mobile Computing | Year: 2012

The WiMAX Forum has defined a two-tiered mobility management to minimize handover delay and packet loss. However, it leads to another problem: When to perform ASN GW relocation? The standards only define the ASN GW relocation procedures without specifying when the ASN GW relocation should be performed. It is left for vendors and operators to develop their own proprietary solutions. In this paper, we propose an algorithm, which incorporates traditional Admission Control (AC) and Wiener Process (WP)-based prediction algorithms to determine when to carry out ASN GW relocation. We further develop an analytical model to analyze the proposed algorithm. Simulations are also conducted to evaluate the performance of the proposed algorithm. The results show that the proposed algorithm can improve the performance significantly in terms of blocking probability, dropping probability, average serving rate, and average signaling overhead. © 2006 IEEE. Source

Lin C.-P.,National Chiao Tung University
International Journal of Human-Computer Interaction | Year: 2010

Drawing upon social cognitive theory (SCT), this research postulates several personal and environmental factors as key drivers of virtual community loyalty behavior in online settings. An empirical testing of this model, by investigating undergraduate students' participation in communities of online games, reveals the applicability of SCT in virtual communities. The study's test results show that the influences of both affective commitment and social norms on community loyalty behavior are significant, whereas the influences of both exchange ideology and social support on community loyalty behavior are insignificant. This research contributes to the online community literature by assessing critical antecedent factors to the unexplored area of community loyalty behavior, by validating idiosyncratic drivers of community loyalty behavior and by performing an operationalization of affective commitment and social norms in a virtual world. Last, managerial implications and limitations of this research are provided. © Taylor & Francis Group, LLC. Source

Wang C.-C.,National Chiao Tung University | Liaw J.-S.,Industrial Technology Research Institute of Taiwan
International Journal of Heat and Mass Transfer | Year: 2012

This study examines the airside performance of the herringbone wavy fin-and-tube heat exchangers in dehumidifying condition having a larger diameter tube (D c = 16.59 mm) with the tube row ranging from 2 to 12. Test results are compared to that of dry conditions and plain fin geometry. Upon the influence of surface condition (dry or wet) on the heat transfer performance, the heat transfer performance in dehumidifying condition normally exceeds that in dry condition, and is more pronounced with the rise of tube row or reduction of fin pitch. By contrast, it is found that the heat transfer coefficient for plain fin geometry in dehumidifying condition is slightly lower than that in dry condition. The pressure drops in wet condition is much higher than that in dry condition. However, the difference in pressure drop amid dry and dehumidifying condition for wavy fin configuration is less profound as that of plain fin geometry. © 2012 Elsevier Ltd. All rights reserved. Source

Lee G.-S.,National Chiao Tung University
Journal of Combinatorial Optimization | Year: 2013

The Stein-Lovász theorem provides an algorithmic way to deal with the existence of certain good coverings, and thus offers bounds related to some combinatorial structures. An extension of the classical Stein-Lovász theorem for multiple coverings is given, followed by some applications for finding upper bounds of the sizes of (d,s out of r;z]-disjunct matrices and (k,m,c,n;z)-selectors, respectively. This gives a unified treatment for some previously known results relating to various models of group testing. © 2011 Springer Science+Business Media, LLC. Source

Chen C.-h.,National Chiao Tung University
Computers and Education | Year: 2010

Recently, more and more researchers have been exploring uses of mobile technology that support new instructional strategies. Based on research findings related to peer and self assessment, this study developed a Mobile Assessment Participation System (MAPS) using Personal Digital Assistants (PDAs) as the platform. In addition, the study proposes an implementation model of the MAPS that should facilitate the effectiveness of self- and peer-assessment in classrooms. The researcher argues that teachers and students can benefit from MAPS in various regards including more flexible assessment arrangement, more efficient use of time, and more opportunities for student reflection on learning and assessment. Thirty-seven students taking teacher-education courses with the researcher participated in this study, and these students employed the MAPS to conduct two-round assessment activities that would help these students assess both their own and one another's final projects. Both the students' valid responses in a survey herein and scores obtained from the assessment activities confirmed the benefits of the MAPS and its implementation model. Yet, the students voiced such concerns as the objectivity of peer-assessment and the difficulty of providing constructive feedback, and the correlation analysis indicated a lack of consistency between teacher-grading and student-grading. © 2010 Elsevier Ltd. All rights reserved. Source

Wang Y.-S.,National Chiao Tung University | Chi M.-T.,National Chengchi University
IEEE Transactions on Visualization and Computer Graphics | Year: 2011

We introduce a focus+context method to visualize a complicated metro map of a modern city on a small displaying area. The context of our work is with regard the popularity of mobile devices. The best route to the destination, which can be obtained from the arrival time of trains, is highlighted. The stations on the route enjoy larger spaces, whereas the other stations are rendered smaller and closer to fit the whole map into a screen. To simplify the navigation and route planning for visitors, we formulate various map characteristics such as octilinear transportation lines and regular station distances into energy terms. We then solve for the optimal layout in a least squares sense. In addition, we label the names of stations that are on the route of a passenger according to human preferences, occlusions, and consistencies of label positions using the graph cuts method. Our system achieves real-time performance by being able to report instant information because of the carefully designed energy terms. We apply our method to layout a number of metro maps and show the results and timing statistics to demonstrate the feasibility of our technique. © 2011 IEEE. Source

Rosenstein B.,National Chiao Tung University | Rosenstein B.,Ariel University | Lewkowicz M.,Ariel University | Maniv T.,Technion - Israel Institute of Technology
Physical Review Letters | Year: 2013

The long-standing controversy concerning the effect of electron-electron interaction on the electrical conductivity of an ideal graphene sheet is settled. Performing the calculation directly in the tight binding approach without the usual prior reduction to the massless Dirac (Weyl) theory, it is found that, to leading order in the interaction strength α=e2/ v 0, the dc conductivity σ/σ0= 1+Cα+O(α2) is significantly enhanced with respect to the independent-electron result σ0, i.e., with the value C=0.26. The ambiguity characterizing the various existing approaches is nontrivial and related to the chiral anomaly in the system. In order to separate the energy scales in a model with massless fermions, contributions from regions of the Brillouin zone away from the Dirac points have to be accounted for. Experimental consequences of the relatively strong interaction effect are briefly discussed. © 2013 American Physical Society. Source

Hu Y.J.,National Chiao Tung University
BMC medical informatics and decision making | Year: 2012

Appropriate postoperative pain management contributes to earlier mobilization, shorter hospitalization, and reduced cost. The under treatment of pain may impede short-term recovery and have a detrimental long-term effect on health. This study focuses on Patient Controlled Analgesia (PCA), which is a delivery system for pain medication. This study proposes and demonstrates how to use machine learning and data mining techniques to predict analgesic requirements and PCA readjustment. The sample in this study included 1099 patients. Every patient was described by 280 attributes, including the class attribute. In addition to commonly studied demographic and physiological factors, this study emphasizes attributes related to PCA. We used decision tree-based learning algorithms to predict analgesic consumption and PCA control readjustment based on the first few hours of PCA medications. We also developed a nearest neighbor-based data cleaning method to alleviate the class-imbalance problem in PCA setting readjustment prediction. The prediction accuracies of total analgesic consumption (continuous dose and PCA dose) and PCA analgesic requirement (PCA dose only) by an ensemble of decision trees were 80.9% and 73.1%, respectively. Decision tree-based learning outperformed Artificial Neural Network, Support Vector Machine, Random Forest, Rotation Forest, and Naïve Bayesian classifiers in analgesic consumption prediction. The proposed data cleaning method improved the performance of every learning method in this study of PCA setting readjustment prediction. Comparative analysis identified the informative attributes from the data mining models and compared them with the correlates of analgesic requirement reported in previous works. This study presents a real-world application of data mining to anesthesiology. Unlike previous research, this study considers a wider variety of predictive factors, including PCA demands over time. We analyzed PCA patient data and conducted several experiments to evaluate the potential of applying machine-learning algorithms to assist anesthesiologists in PCA administration. Results demonstrate the feasibility of the proposed ensemble approach to postoperative pain management. Source

Kim Y.,Chung - Ang University | Lai M.-C.,National Chiao Tung University
Journal of Computational Physics | Year: 2010

In this paper, we develop an immersed boundary (IB) method to simulate the dynamics of inextensible vesicles interacting with an incompressible fluid. In order to take into account the inextensibility constraint of the vesicle, the penalty immersed boundary (pIB) method is used to virtually decouple the fluid and vesicle dynamics. As numerical tests of our current pIB method, the dynamics of single and multiple inextensible vesicles under shear flows have been extensively explored, and compared with the previous literature. The method is also validated by a series of convergence study, which confirms its consistent first-order accuracy on the velocity field, the vesicle configuration, the vesicle area and the perimeter errors. In addition, the method is also applied to study a binary-component vesicle problem. © 2010 Elsevier Inc. Source

Ng Mou Kehn M.,National Chiao Tung University
IEEE Transactions on Microwave Theory and Techniques | Year: 2015

The substrate integrated waveguide (SIW) comprising rectangular via-holes is herein treated by a rigorous full-wave modal analysis using the moment method entailing Green's functions for rectangular cavities and planar multilayer structures in the spectral domain. Modal dispersion graphs generated by this solution approach are compared with those obtained by an independent commercial full-wave solver. The ability of the modal solution in treating SIW junctions and discontinuities is demonstrated by the treatment of an interconnection between a conventional waveguide and a SIW using the mode-matching technique. Inhomogeneities within SIWs can also be accommodated by the technique, as showcased by a specific example of the so-called hard sidewalled SIW. Three avenues of losses, namely, dielectric, side-leakage, and conductor losses, are also investigated, thereby elucidating a tradeoff between the latter two. © 1963-2012 IEEE. Source

Hwang S.-J.,National United University | Jeng S.-C.,National Chiao Tung University | Hsieh I.-M.,National United University
Optics Express | Year: 2010

The pretilt angles of liquid crystal molecules can be controlled by using conventional polyimide (PI) alignment material doped with different concentrations of Polyhedral Oligomeric Silsequioxanes (POSS) nanoparticles, which have been observed to spontaneously induce vertical alignment. The addition of POSS in the homogenous PI changes the surface energy of the alignment layer and generates a variable pretilt angle. Experimental results demonstrate that the pretilt angle θ p is a function of the POSS concentration, and can be tuned continuously over the range of 0°<θ p<90°. The polar anchoring energy of POSS/PI alignment layer is almost constant regardless of the POSS concentration. This technique is very simple and is compatible with methods familiar in the current LCD industry. © 2010 Optical Society of America. Source

Chow C.W.,National Chiao Tung University | Yeh C.H.,Industrial Technology Research Institute of Taiwan
Optics Express | Year: 2010

As different high speed signal-remodulation wavelength division multiplexed - passive optical network (WDM-PON) solutions up to 10 Gb/s have been proposed, researchers are going to further increase the data rate of PON towards 40 Gb/s or higher. However, scaling up from 10 Gb/s/wavelength to 40 Gb/s/wavelength PON is very challenging. Although many studies have been performed on upgrading the exiting 10 Gb/s network to 40 Gb/s, the study of the 40 Gb/s signal-remodulation network is very little. In this work, we will first study the chromatic dispersion effect on the signal-remodulation PON. Then, we will propose and demonstrate a signal-remodulation PON using 40-Gb/s downstream differential-phase shift keying (DPSK) and 40-Gb/s upstream on-off keying (OOK) signals. By using the reduced modulation index (RMI) of the downstream DPSK signal, the tolerance to the residual chromatic dispersion of the whole system can be greatly enhanced. Due to the reduced impact of the accumulated chromatic dispersion, the quality of the upstream remodulated OOK signal can be significantly improved. Besides, by detecting the downstream demodulated DPSK signal at the destructive output port of the demodulator, good quality of the demodulated DPSK signal can still be achieved. © 2010 Optical Society of America. Source

Huang H.-C.,National University of Kaohsiung | Fang W.-C.,National Chiao Tung University
Simulation Modelling Practice and Theory | Year: 2010

In this paper, we propose a practical application for copyright protection of images with watermarking. The EXIF metadata of images and error-control codes are integrated into our algorithm and corresponding applications. Application for robust watermarking is one of the major branches in digital rights management (DRM) systems and digital forensics. Here, we focus on the copyright protection for images taken by ordinary cameras. By use of robust watermarking, it generally alters selected coefficients of the contents to accomplish the embedding process. Should the received image be in question, the watermark embedded beforehand can be extracted to indicate the copyright owner of such an image. We consider not only the image contents itself, but we also employ the EXIF metadata, which serves as the role of watermark, to be integrated into our scheme to make copyright protection possible. Moreover, for enhancing the performance for copyright protection, channel coding is employed and better protection capability can be expected. Taking the manufacturer, camera model, date and time stamp, and other important information in the EXIF metadata into account, conventional watermarking techniques can be applied to ordinary pictures taken by ourselves, and watermarked images with good quality can be produced. Even when the marked image has been intentionally modified, the original EXIF with selected information can mostly be recovered from the channel decoding process. Simulation results present the effectiveness of such an implementation. © 2009 Elsevier B.V. All rights reserved. Source

Chang L.-P.,National Chiao Tung University
IEEE Transactions on Computers | Year: 2010

Replacing power-hungry disks with NAND-flash-based solid-state disks (SSDs) is a recently emerging trend in flash-memory applications. One important SSD design issue is achieving a good balance between cost, performance, and lifetime. This study introduces a hybrid approach to large SSDs that combines MLC NAND flash and SLC NAND flash. Each of these flash architectures has its own drawbacks and benefits, and this study proposes that the two can complement each other. However, there are technical challenges pertaining to data placement, data migration, and wear leveling in heterogeneous NAND flash. The experimental results of our study show that combining 256 MB SLC flash with 20 GB MLC flash produces a hybrid SSD. This hybrid SSD is 1.8 times faster than a purely MLC-flash-based SSD in terms of average response time and improves energy consumption by 46 percent. The proposed hybrid SSD costs only four percent more than a purely MLC-flash-based SSD. The extra cost of a hybrid SSD is very limited and rewarding. © 2006 IEEE. Source

Watanabe H.,National Chiao Tung University
IEEE Transactions on Electron Devices | Year: 2010

The single-electron general-purpose device simulator is improved to carry out a wide-range transient analysis from 1 ps to 10 years. We apply this simulator to a floating gate (FG) nonvolatile memory cell in order to simulate a degradation mode of data retention owing to the direct tunneling enhanced by the fixed charge stored by a local trap in an interpoly dielectric. The scaling impact of ideal high-K interpoly dielectric FG nonvolatile memory cell is also investigated. © 2006 IEEE. Source

Chen C.,National Chiao Tung University | Tong H.M.,Advanced Semiconductor Engineering Inc. | Tu K.N.,University of California at Los Angeles
Annual Review of Materials Research | Year: 2010

Pb-free solders have replaced Pb-containing SnPb solders in the electronic packaging industry due to environmental concerns. Both electromigration (EM) and thermomigration (TM) have serious reliability issues for fine-pitch Pb-free solder bumps in the flip-chip technology used in consumer electronic products. We review the unique features of EM and TM in flip-chip solder bumps, emphasizing the effects of current crowding and Joule heating. In addition, the challenges to a better understanding of EM and TM in Pb-free solders are discussed. For example, the anisotropic nature of Sn microstructure in Pb-free solders can enhance the dissolution rates of Ni and Cu in solders driven by EM and TM. © 2010 by Annual Reviews. All rights reserved. Source

Chen Y.-Y.,Lunghwa University of Science and Technology | Hsieh C.-R.,National Chiao Tung University
IEEE Electron Device Letters | Year: 2010

The charge trapping and detrapping characteristics of the fluorinated hafnium oxide/oxynitride (HfO2SiON) gate stack are investigated. Although incorporation of fluorine in the bulk stack had been proven to eliminate both bulk and interface trap densities due to HfF and SiF bond formation, respectively, the effective trapping barrier of the device with fluorine incorporation (1.29 eV) is deeper than without fluorine incorporation (1.13 eV), indicating that the detrapping ability of the fluorinated devices may limit future fluorine process applications. © 2010 IEEE. Source

Tsai Y.-D.,National Tsing Hua University | Wu X.N.,CAS Academy of Mathematics and Systems Science | Yang Y.,National Chiao Tung University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

We study the critical phenomena of Kerr-AdS black hole. Phase structures are observed at different temperatures, T L, T c1 and T c2 with various features. We discuss the thermal stability considering the isothermal compressibility and how phase transitions related to each other. The asymptotic value of the angular momentum also has an implication on separating stable and unstable part. Near critical temperature T c1, the order parameter is determined to calculate the critical exponents. All the critical exponents (α,β,γ,δ)=(0,12,1, 3) are identical to that of mean field systems. We plot the phase diagram near this critical point, and discuss the scaling symmetry of the free energy. © 2012 American Physical Society. Source

Wu J.-Y.,National Chiao Tung University
IEEE Transactions on Wireless Communications | Year: 2010

Transmit precoding is a key technique for facilitating blind channel estimation at the receiver but the impact due to precoding on the channel capacity is scarcely addressed in the literature. In this paper we consider the single-carrier block transmission with cyclic prefix, in which a recently proposed diagonal-precoding assisted blind channel estimation scheme via covariance matching is adopted to acquire the channel information. It is shown that, when perfect channel knowledge is available at the receiver, the optimal noise resistant precoder proposed in the literature incurs the worst-case capacity penalty. When the coherent interval is finite, channel mismatch occurs due to finite-sample covariance matrix estimation. Thus, we aim to determine how much of the coherent interval should be dedicated to precoding in order to trade channel estimation accuracy for the maximal capacity. Toward this end, we leverage the matrix perturbation theory to derive a closed-form capacity measure which explicitly takes account of the channel uncertainty in the considered blind estimation setup. Such a capacity metric is seen to be a complicated function of the precoding interval. To facilitate analysis, an approximate formula for the derived capacity measure is further given. This allows us to find a closed-form estimate of the capacity-maximizing precoding time fraction, and can also provide insights into the optimal tradeoff between channel estimation accuracy and achievable capacity. Numerical simulations are used for evidencing the proposed analytic study. © 2010 IEEE. Source

Kuo S.-W.,National Sun Yat - sen University | Chang F.-C.,National Chiao Tung University
Progress in Polymer Science (Oxford) | Year: 2011

This review describes the syntheses of polyhedral oligomeric silsesquioxane (T8-POSS) compounds, the miscibility of POSS derivatives and polymers, the preparation of both multifunctional and monofunctional monomers and polymers containing POSS including styryl-POSS, methacrylate-POSS, norbornyl-POSS, vinyl-POSS, epoxy-POSS, phenolic-POSS, benzoxazine-POSS, amine-POSS, and hydroxyl-POSS. The thermal, dynamic mechanical, electrical, and surface properties of POSS-related polymeric nanocomposites prepared from both monofunctional and multifunctional POSS monomers are discussed. In addition, we describe the applications of several high-performance POSS nanocomposites in such systems as light emitting diodes, liquid crystals, photo-resist materials, low-dielectric constant materials, self-assembled block copolymers, and nanoparticles. © 2011 Elsevier Ltd. All rights reserved. Source

Wang C.-C.,National Chiao Tung University
Heat Transfer Engineering | Year: 2012

A new concept of heat transfer enhancement applicable for finned tube air-cooled heat exchangers is proposed. The concept called a 'partial bypass' arises from an effective usage of the ineffective air stream (bypass airflow). The concept is rather simple, focusing on increasing the Q max at the rear part of the heat exchanger. The concept can be implemented either with substantial increase of heat transfer rate without additional pressure drop penalty or with identical heat transfer rate but accompanies a much smaller pressure drop. Both the temperature difference amid inlet air and water and the mass flow rate into the second heat exchanger can be increased simultaneously. This eventually leads to an even higher Q max at the second heat exchanger and as a result a much larger heat transfer rate. The concept is especially helpful in the design of a deep tube bank and can be implemented with sufficient augmentation without additional penalty. Source

Sze S.M.,National Chiao Tung University
Journal of Nanoscience and Nanotechnology | Year: 2012

In the past 45 years (from 1967 to 2012), the non-volatile semiconductor memory (NVSM) has emerged from a floating-gate concept to the prime technology driver of the largest industry in the world\-the electronics industry. In this paper, we briefly review the historical development of NVSM and project its future trends to the year 2020. In addition, we consider NVSM's wide-range of applications from the digital cellular phone to tablet computer to digital television. As the device dimension is scaled down to the deca-nanometer regime, we expect that many innovations will be made to meet the scaling challenges, and NVSM-inspired technology will continue to enrich and improve our lives for decades to come. Copyright © 2012 American Scientific Publishers. All rights reserved. Source

Li Y.-M.,National Chiao Tung University
Decision Support Systems | Year: 2010

The paper considers the pricing and allocation issues of distributing digital contents via Web and P2P channels. Utilizing a game theoretic model, the allocation equilibrium with respect to various business goals is examined. We find that the P2P channel is always under-utilized in an organization, and present an incentive scheme to achieve an efficient channel configuration. Under a market structure with sequential moves, both channels set higher price and collect higher profit. Particularly, the second mover enjoys higher price and market share. A provider with integrated channels will charge a higher price on the Web channel and the Web channel becomes under-utilized. © 2010 Elsevier B.V. All rights reserved. Source

Chen Y.F.,National Chiao Tung University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2011

The geometry of classical dynamics in coupled oscillators with SU(2) transformations is explored and found to be relevant to a family of continuous-transformation orbits between Lissajous and trochoidal curves. The quantum wave-packet coherent states are derived analytically to correspond exactly to the transformation geometry of classical dynamics. By using the quantum wave-packet coherent states derived herein, stationary coherent states are constructed and are shown to possess spatial patterns identical to the transformation geometry between Lissajous and trochoidal orbits. © 2011 American Physical Society. Source

Kuo J.-C.,Industrial Technology Research Institute of Taiwan | Chen M.-C.,National Chiao Tung University
Food Control | Year: 2010

For temperature sensitive and perishable products (TSPPs) logistics, a special type of supply chain management called Cold Chain Management (CCM), has been established. Temperature monitoring and control are essential mechanisms in CCM, because they are necessary for maintaining food safety and quality. However, they are costly to logistics service providers (LSPs). In this paper, a logistics service model based on the advancement of the Multi-Temperature Joint Distribution System, namely MTJD, is being proposed for the food cold chain. The proposed service model facilitates innovation in logistics services and gives the logistics sector a competitive advantage in the area of thermal protection for perishable shipments and temperature sensitive products. Smaller shipments and timely deliveries offer unique challenges when operating a cold chain. The MTJD-based model is designed with these challenges in mind. A case study is performed by using the regulative cycle. In this paper, an MTJD-based model is presented according to the requirements of the food chain and the operations of a 3PL in Taiwan. MTJD provides a new scheme for continuously temperature-controlled logistics, which can jointly deliver and store multi-temperature goods. © 2009 Elsevier Ltd. All rights reserved. Source

Chen J.-K.,Tamkang University | Chen I.-S.,National Chiao Tung University
Expert Systems with Applications | Year: 2011

Since the overall quality of Taiwanese university education has been decreasing in recent years, and universities are losing their competitive advantage while facing foreign countries' education systems and the threat of closing, upgrading innovation performance and improving total quality performance (Inno-Qual performance) so as to enhance overall operational performance have become an urgent issue. Although relative measurement models are increasingly being used for conquering the above-mentioned difficulties, such as the Inno-Qual performance system (IQPS), which integrates the features of innovation and TQM, currently, no studies empirically evaluate the efficiency of such improvement, meaning that the costs of using the Inno-Qual performance system are increasing, particularly the human administrative cost for providing intellectual products, which is the nature of higher education. To overcome this problem, in this study, the IQPS is adopted by using data envelopment analysis (DEA) to evaluate the Inno-Qual efficiency of 99 Taiwanese universities divided into five types (research-intensive, teaching-intensive, profession-intensive, research & teaching-intensive, and education-in-practice-intensive). On the basis of the empirical results, we found that over half (73%) of the universities are highly inefficient in improving the Inno-Qual performance, and thus we conclude that improving the Inno-Qual efficiency based on our results will be helpful for reducing the majority of cost expenditures. © 2010 Elsevier Ltd. All rights reserved. Source

Yang J.L.,Lee Ming Institute of Technology | Tzeng G.-H.,Kainan University | Tzeng G.-H.,National Chiao Tung University
Expert Systems with Applications | Year: 2011

Traditionally, most importance-assessing methods used to demonstrate the importance among criteria by preference weightings are based on the assumptions of additivity and independence. In fact, people have found that using such an additive model is not always feasible because of the dependence and feedback among the criteria to somewhat different degrees. To solve the issue the analytic network process (ANP) method is proposed by Saaty. The general method is easy and useful for solving the above-mentioned problem. However in ANP procedures, using average method (equal cluster-weighted) to obtain the weighted supermatrix seems to be irrational because there are different degrees of influence among the criteria. Therefore, we intended to propose an integrated multiple criteria decision making (MCDM) techniques which combined with the decision making trial and evaluation laboratory (DEMATEL) and a novel cluster-weighted with ANP method in this paper, in which the DEMATEL method is used to visualize the structure of complicated causal relationships between criteria of a system and obtain the influence level of these criteria. And, then adopt these influence level values as the base of normalization supermatrix for calculating ANP weights to obtain the relative importance. Additionally, an empirical study is illustrated to demonstrate that the proposed method is more suitable and reasonable. By the concept of ideal point, some important conclusions drawn from a practical application can be referred by practitioners. © 2010 Elsevier Ltd. All rights reserved. Source

Tsai M.-J.,National Chiao Tung University
Multimedia Tools and Applications | Year: 2011

Wavelet tree based watermarking algorithms are generally using the wavelet coefficient energy difference for copyright protection and ownership verification. Since there are cryptanalysis-based methods addressed for successfully attacking wavelet tree based watermarking algorithm of wavelet tree quantization (WTQ), it is the motivation in this research to devise a scheme to improve WTQ's robustness. Furthermore, the combination of wavelet tree based watermarking techniques, chaotic system for block based scrambling techniques have not been seen or few discussed in the literatures. The study in this paper has presented such research findings and contribution for the academic and industry fields. Therefore, a chaotic system is adopted for WTQ to counteract the attacks in this paper. The digital image is first split into many blocks and the chaotic system is applied to scramble the image before the implementation of WTQ. The experimental results demonstrate the effectiveness of using chaotic system to enhance the security of WTQ, especially, to resist cryptanalysis attack. In addition, such mechanism also works for other advanced wavelet tree based algorithms like wavelet tree group modulation (WTGM) and dynamic energy enabled differentiation (called DEED) watermarking techniques. © 2010 Springer Science+Business Media, LLC. Source

Tsai S.-H.,National Chiao Tung University
IEEE Transactions on Wireless Communications | Year: 2011

The beamforming vectors of an equal gain transmission (EGT) contains phase information only and thereby enjoys several implementational advantages when compared to the optimal scheme, i.e. maximum ratio transmission (MRT). The implementational advantages make EGT a promising solution for simple transceiver design while offering a performance comparable to that of MRT. This solution motivates us to explore how close the performance can be between EGT and MRT. The maximum SNR loss between EGT and MRT is known to be 1.05 dB in MISO channels. However, little is known about the SNR loss in MIMO channels, since no closed-form solution is available for the best EGT in MIMO channels. In this work, a suboptimal closed-form EGT design for MIMO channels is proposed and its performance is analyzed. Interestingly, the maximum SNR loss between the proposed EGT and the MRT (both employing MRC in receiver) in MIMO channels is shown to be approximately 1.05 dB as well. Moreover, instead of applying conventional all transmit antennas, this study proposes to adopt antenna selection, to further improve the performance of EGT. Two antenna selection algorithms are proposed and the corresponding performance is analyzed. When the proposed antenna selection algorithms are applied to EGT, the SNR loss between EGT and MRT can be reduced to as low as 0.45-0.65 dB, with the numbers of transmit antennas ranging from 4 to 8. One of the proposals with fixed number of transmit antennas not only outperforms conventional EGT but also requires fewer number of RF (radio frequency) components; also, it employs constant power in each transmit antenna like EGT does. As a result, hardware complexity can be reduced by this proposal. Furthermore, design strategies to apply the proposed EGT and antenna selection algorithms in systems with limited feedback are also suggested. © 2011 IEEE. Source

Tsai M.-T.,Chang Gung University | Chan M.-C.,National Chiao Tung University | Chan M.-C.,Chi Mei Medical Center
Optics Letters | Year: 2014

Simultaneous multispectral generation in 0.8, 1.0, and 1.3 μm wavelength ranges by efficient energy conversions of 1.0 μm wavelength femtosecond pulses through a nonlinear fiber was reported. The output spectral range of this multispectral light source was composed of 0.6-0.9 μm blue-shifted Cherenkov radiation (CR), 1.0 μm residual pump, and 1.1-1.7 μm red-shifted soliton self-frequency shift (SSFS) with more than 1 mW/nm power-spectral densities. Output characteristics of the multispectral light source were then quantitatively analyzed and the central wavelengths of CR and SSFS emissions can be further easily adjusted by changing the input power into wavelength conversion fiber. Example spectral-domain optical coherence tomography (OCT) images of an IR card and finger skin were also performed with the demonstrated source. Due to the advantages of its simplicity, easily operated, and wavelength tunability, the reported multispectral source could be widely applicable for various spectroscopic OCT applications. © 2014 Optical Society of America. Source

Spilt J.L.,University of Amsterdam | Hughes J.N.,Texas A&M University | Wu J.-Y.,National Chiao Tung University | Kwok O.-M.,Texas A&M University
Child Development | Year: 2012

This study modeled teacher-student relationship trajectories throughout elementary school to predict gains in achievement in an ethnic-diverse sample of 657 academically at-risk students (mean age=6.57 years, SD=.39). Teacher reports of warmth and conflict were collected in Grades 1-5. Achievement was tested in Grades 1 and 6. For conflict, low-stable (normative), low-increasing, high-declining, and high-stable trajectories were found. For warmth, high-declining (normative) and low-increasing patterns were found. Children with early behavioral, academic, or social risks were underrepresented in the normative trajectory groups. Chronic conflict was most strongly associated with underachievement. Rising conflict but not declining Conflict coincided with underachievement. The probability of school failure increased as a function of the timing and length of time children were exposed to relational adversity. © 2012 The Authors. Child Development © 2012 Society for Research in Child Development, Inc. Source

Liao Y.-H.,National Penghu University of Science and Technology | Chen H.C.,National Chiao Tung University
IEEE Transactions on Industrial Electronics | Year: 2015

In this paper, a simplified pulsewidth modulation with switching constraint control scheme is proposed to eliminate the circulating currents for bidirectional paralleled ac/dc converters in grid-tied system. The proposed control scheme can reduce the circulating currents and does not need additional current sensors and communication device among paralleled converters compared with conventional methods. Therefore, the paralleled system cost can be reduced. In addition, the current shaping and sharing between the paralleled converters can be well accomplished so that the overall performance of the paralleled converter system can be raised. Furthermore, the dc, ac, and self-generated circulating currents are clearly analyzed by graphics, and the synchronous circulating currents are first explored. Finally, a prototype system is constructed, and the proposed control scheme is implemented using a Spartan-3E XC3S250E FPGA. Both simulation and experimental results verify the validity of the proposed theory and control scheme. © 1982-2012 IEEE. Source

Chiao M.-L.,National Chiao Tung University | Chang D.-W.,National Cheng Kung University
IEEE Transactions on Computers | Year: 2011

A Flash Translation Layer (FTL) provides a block device interface on top of flash memory to support disk-based file systems. Due to the erase-before-write feature of flash memory, an FTL usually performs out-of-place updates and uses a cleaning procedure to reclaim stale data. A hybrid address translation (HAT)-based FTL combines coarse-grained and fine-grained address translation to achieve good performance while keeping the size of the mapping information small. In this paper, we propose a new HAT-based FTL, called ROSE, which includes three novel techniques for reducing the cleaning cost. First, it reduces high-cost reclamation by preventing data in an entire-block sequential write from being placed into multiple physical blocks while eliminating the cleaning cost resulting from mispredicting random or semisequential writes as sequential ones. Second, it uses a merge-aware cleaning policy that considers both the block age and the merge cost in a HAT-based FTL for improving the cleaning efficiency. Third, it delays the erasure of obsolete blocks and reuses their free pages for buffering more writes. Simulation results show that the proposed FTL outperforms existing HAT-based FTLs in terms of both cleaning cost and flash write time by up to 47 times and 1.6 times, respectively. © 2011 IEEE. Source

Kuo H.-Y.,National Chiao Tung University
Smart Materials and Structures | Year: 2013

This paper studies the effective behavior of piezoelectric and piezomagnetic circular fibrous composites with imperfect interfaces under longitudinal shear with in-plane electromagnetic fields. Two kinds of imperfect contact are investigated: mechanically stiff and dielectrically/magnetically highly conducting interfaces, and mechanically compliant and dielectrically/magnetically weakly conducting interfaces. For the former case, the potential field is continuous, while the normal component of the flux undergoes a discontinuity across the interface. For the latter case, the normal component of the flux is continuous, while there is a jump of potential field at such a contact. The classic work of Rayleigh (1892 Phil. Mag. 34 481-502) in a periodic conductive perfect composite is generalized to the current coupled magnetoelectroelastic composites with imperfect interfaces. It is shown that the expression of the effective property has exactly the same form as that in the ideal coupling composite. Finally, this method is used to study BaTiO 3-CoFe2O4 composites and provide insights into enhancing the effective magnetoelectric voltage coefficient by properly choosing the interface. © 2013 IOP Publishing Ltd. Source

Cheng C.H.,National Tsing Hua University | Chin A.,National Chiao Tung University | Yeh F.S.,National Tsing Hua University
Applied Physics Letters | Year: 2011

We report a high performance and low-power operated resistive memory. Using stacked covalent-bond-dielectric GeOx on metal-oxide SrTiO x to form the cost-effective Ni/ GeOx / SrTiOx /TaN resistive random access memory, ultralow set power of small 1 μW (0.9 μA at 1.2 V), reset power of 13 pW (0.13 nA at 0.1 V), fast 50 ns switching time and good 106 cycling endurance are realized. © 2011 American Institute of Physics. Source

Chen C.-H.,National Chiao Tung University
Optics Letters | Year: 2014

We theoretically present the analysis and design of a nanoplasmonic bandpass filter with flat-top spectral characteristics by cascading a series of directly connected rectangular ring resonators based on metal-insulator-metal waveguides. Analyzed by the equivalent lumped circuit model of the transmission line to plasmonic waveguides, the transmission properties of a symmetric rectangular ring resonator with the directly connected input and output waveguides are approximately the same as that of a Fabry-Perot resonator. Then the thin-film design methodology is applied to realize a plasmonic bandpass filter with the squared passband. An example of cascaded tworectangular ring resonator structure is numerically demonstrated by using the transmission line model and 2D finite difference time domain method. © 2014 Optical Society of America. Source

Chien J.-T.,National Chiao Tung University
IEEE/ACM Transactions on Speech and Language Processing | Year: 2015

This paper presents the group sparse learning for acoustic models where a sequence of acoustic features is driven by Markov chain and each feature vector is represented by groups of basis vectors. The group of common bases represents the features across Markov states within a regression class. The group of individual basis compensates the intra-state residual information. Laplace distribution is used as the sparse prior of sensing weights for group basis representation. Laplace parameter serves as regularization parameter or automatic relevance determination which controls the selection of relevant bases for acoustic modeling. The groups of regularization parameters and basis vectors are estimated from training data by maximizing the marginal likelihood over sensing weights which is implemented by Laplace approximation using the Hessian matrix and the maximum a posteriori parameters. Model uncertainty is compensated through full Bayesian treatment. The connection of Laplace group sensing to lasso regularization is illustrated. Experiments on noisy speech recognition show the robustness of group sparse acoustic models in presence of different noise types and SNRs. © 2016 ACM. Source

Zhang Y.-J.,Tianjin University | Li Z.-Q.,Tianjin University | Lin J.-J.,National Chiao Tung University
Physical Review B - Condensed Matter and Materials Physics | Year: 2011

We have measured the Hall coefficient RH and the electrical conductivity σ of a series of ultrathin indium-tin-oxide films between 2 and 300 K. A robust RHlnT law is observed in a considerably wide temperature range of 2 and ∼120K. This lnT dependence is explained as originating from the electron-electron interaction effect in the presence of granularity as theoretically predicted. Furthermore, we observed a σlnT law from 3 K up to several tens K, which also arose from the Coulomb interaction effect in inhomogeneous systems. These results provide strong experimental support for the current theoretical concepts for charge transport in granular metals with intergrain tunneling conductivity gT1. © 2011 American Physical Society. Source

Lin T.-Y.,National Chiao Tung University
Mutation Research - Fundamental and Molecular Mechanisms of Mutagenesis | Year: 2016

Phages are the most abundant biological entities and influence prokaryotic communities on Earth. Comparing closely related genomes sheds light on molecular events shaping phage evolution. Simple sequence repeat (SSR) variations impart over half of the genomic changes between T7M and T3, indicating an important role of SSRs in accelerating phage genetic divergence. Differences in coding and noncoding regions of phages infecting different hosts, coliphages T7M and T3, Yersinia phage ϕ(symbol)YeO3-12, and Salmonella phage ϕ(symbol)SG-JL2, frequently arise from SSR variations. Such variations modify noncoding and coding regions; the latter efficiently changes multiple amino acids, thereby hastening protein evolution. Four classes of events are found to drive SSR variations: insertion/deletion of SSR units, expansion/contraction of SSRs without alteration of genome length, changes of repeat motifs, and generation/loss of repeats. The categorization demonstrates the ways SSRs mutate in genomes during phage evolution. Indels are common constituents of genome variations and human diseases, yet, how they occur without preexisting repeat sequence is less understood. Non-repeat-unit-based misalignment-elongation (NRUBME) is proposed to be one mechanism for indels without adjacent repeats. NRUBME or consecutive NRUBME may also change repeat motifs or generate new repeats. NRUBME invoking a non-Watson-Crick base pair explains insertions that initiate mononucleotide repeats. Furthermore, NRUBME successfully interprets many inexplicable human di- to tetranucleotide repeat generations. This study provides the first evidence of SSR variations expediting phage divergence, and enables insights into the events and mechanisms of genome evolution. NRUBME allows us to emulate natural evolution to design indels for various applications. © 2016 Elsevier B.V. Source

Wong K.I.,National Chiao Tung University
International Journal of Sustainable Transportation | Year: 2013

Reducing automobile dependency is one of the key challenges in the development of a sustainable transportation system. However, to evaluate the effectiveness of a policy, it is necessary to understand the factors that would influence the choice behavior of travelers. In this paper, the impacts of urban characteristics to the household vehicle ownership level for cars and motorcycles in Macao are investigated. A discrete choice approach is used to estimate the number of vehicles that a household would own using disaggregate household survey data. The result reveals that whereas income has positive effect on both car and motorcycle ownerships, the demographic attributes of the residential locations have different effects to the ownerships of the two vehicle types. We also propose that the motorcycle ownership should be represented at a personal decision level instead of a household level. © 2013 Copyright Taylor and Francis Group, LLC. Source

Gau R.-H.,National Chiao Tung University
IEEE Communications Letters | Year: 2012

In this paper, we propose partitioning group members into subgroups according to their instantaneous channel gains for single-hop wireless multicast flow control. We study the case in which there are a number of logical channels and the access point uses a logical channel to broadcast information to a subgroup. In particular, distinct logical channels could be allocated different levels of transmission power and fractions of time. In order to maximize the network throughput, we formulate and solve a discrete optimization problem. In addition, we use simulation results to show group partition is a promising approach for wireless multicast flow control. © 2012 IEEE. Source

Chen L.J.,National Tsing Hua University | Wu W.W.,National Chiao Tung University
Materials Science and Engineering R: Reports | Year: 2010

In situ investigation of the temperature induced phase transformation, structural and chemical evolution of nanocrystals is important for understanding the structure and stability of nanomaterials. Transmission electron microscopy (TEM), one of the most powerful tools for characterizing nanostructured materials, is essential for the development of nanotechnology. In situ TEM is a technique that allows a direct observation of dynamic properties in nanoscale. Recent development of ultra-high vacuum TEM (UHV-TEM) further enables the investigation on atomic-scale materials systems in a clean environment. The appropriate utilization of the UHV-TEM will be beneficial in studying the fundamental mechanisms of dynamic reactions, formation of transient phase, solid-state amorphization, epitaxial growth, growth kinetics and evolution of defects. In this paper, we present the most recent progress in observing dynamic processes in nanoscale by in situ UHV-TEM. © 2010 Elsevier B.V. All rights reserved. Source

Hung J.-C.,National Chin - Yi University of Technology | Lin C.-C.,National Chiao Tung University
Materials and Design | Year: 2013

Numerous studies have shown the benefit of ultrasonic-vibration assisted metal forming. This benefit include a reduction in forming forces, which might be attributed to the superposition of stress, increased temperatures, the effects of interface friction, and energy absorption of dislocation. This study conducts a series of experiments and analyses to investigate the main mechanisms of a reduction in forming forces during ultrasonic-vibration assisted A6061-T6 aluminum alloy upsetting.The findings of this research confirm that, under frictionless conditions, ultrasonic vibration still reduced forming forces, and ultrasonic vibration can increase the temperature of specimens and soften specimen surface during upsetting. From metallographic analyses and micro-hardness tests, the results reveal that energy absorption of dislocation was occurred during upsetting, which also contribute to the reduction of forming force.This research concludes that the mechanisms of increased temperatures and energy absorption of dislocation can affect the material property and make a reduction in forming forces; however, the interface friction effect has nothing to do with a reduction in forming forces. © 2012. Source

Chen C.-H.,National Chiao Tung University
2012 21st Annual Wireless and Optical Communications Conference, WOCC 2012 | Year: 2012

A compact waveguide crossing constructed by three cascaded multimode tapers on each branch is numerically analyzed by finite difference time domain method, which possesses the size of 3920 nmx3920 nm, the insertion loss of 0.187 dB and the crosstalk of -47.58 dB at the wavelength of 1550 nm and broad transmission spectrum ranging from 1500 to 1600 nm. © 2012 IEEE. Source

Cheng C.-H.,National Tsing Hua University | Yeh F.-S.,National Tsing Hua University | Chin A.,National Chiao Tung University
Advanced Materials | Year: 2011

Very high performance Ni/GeOx/HfON/TaN non-volatile resistive memory is fabricated using the covalently bonded dielectric GeOx and metal oxynitride HfON as well as low cost electrodes. The device shows low set and reset powers, good 85 °C retention, and 105 endurance, which are near to the characteristics of existing commercial flash memory. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Chou C.-H.,University of California at Los Angeles | Chou C.-H.,National Chiao Tung University | Kwan W.L.,University of California at Los Angeles | Hong Z.,University of California at Los Angeles | And 2 more authors.
Advanced Materials | Year: 2011

A metal-oxide-only interconnecting layer for application in inverted polymer tandem solar cells is reported. Good electrical and optical coupling of the two sub-cells is achieved by using a carefully-designed MoO 3/Al/ZnO layer, which leads to a power coversion efficiency of 5.1%. Our results demonstrate that effective connection between polymer bulk heterojunctions can be realized by this facile metal-oxide interlayer. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Chen C.-P.,Industrial Technology Research Institute of Taiwan | Chen Y.-D.,Industrial Technology Research Institute of Taiwan | Chuang S.-C.,National Chiao Tung University
Advanced Materials | Year: 2011

Inverted OPV devices based on sol-gel derived vanadium oxides (VO x) as an interfacial layer are demonstrated. The VOx shows excellent characteristics as a hole-transporting and protecting layer. The constructed devices exhibit enhanced performance with the studied polymers and are highly durable under accelerated conditions for long time periods. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Yeh C.H.,Industrial Technology Research Institute of Taiwan | Chow C.W.,National Chiao Tung University
Optics Express | Year: 2011

We propose and experimentally demonstrate a hybrid radio-over-fiber (ROF) wavelength division multiplexed and time division multiplexed passive optical network (WDM-TDM PON) architecture to mitigate Rayleigh backscattering (RB) interferometric beat noises. Here, only a single wavelength is needed at the central office (CO) to generate the downstream baseband data for optical wired application and optical millimeter-wave (mm-wave) signal for wireless application. The upstream signal is produced by remodulating the downstream signal. No optical filter is required at the optical network unit/remote antenna unit (ONU/RAU) to separate the optical wired and optical mm-wave signals. In the proposed network, 10 Gb/s differential phase shift keying (DPSK) signal is used for the downstream optical wired application and 2.5 Gb/s on-off keying (OOK) signal on 20 GHz carrier is used for the optical mm-wave signal. In each ONU, a reflective optical semiconductor amplifier (RSOA) is used to remodulate and produce a 2.5 Gb/s OOK format for upstream traffic. As the back-refection produced by the downstream DPSK signal and the upstream OOK signal is traveling in different fiber path, RB noise at the CO can be completely mitigated. © 2011 Optical Society of America. Source

Liu K.K.,National Chiao Tung University
Nanotechnology | Year: 2010

A nanoparticle-conjugated cancer drug provides a novel strategy for cancer therapy. In this study, we manipulated nanodiamond (ND), a carbon nanomaterial, to covalently link paclitaxel for cancer drug delivery and therapy. Paclitaxel was bound to the surface of 3-5 nm sized ND through a succession of chemical modifications. The ND-paclitaxel conjugation was measured by atomic force microscope and nuclear magnetic resonance spectroscopy, and confirmed with infrared spectroscopy by the detection of deuterated paclitaxel. Treatment with 0.1-50 microg ml(-1) ND-paclitaxel for 48 h significantly reduced the cell viability in the A549 human lung carcinoma cells. ND-paclitaxel induced both mitotic arrest and apoptosis in A549 cells. However, ND alone or denatured ND-paclitaxel (after treatment with strong alkaline solution, 1 M NaOH) did not induce the damage effects on A549 cells. ND-paclitaxel was taken into lung cancer cells in a concentration-dependent manner using flow cytometer analysis. The ND-paclitaxel particles were located in the microtubules and cytoplasm of A549 cells observed by confocal microscopy. Furthermore, ND-paclitaxel markedly blocked the tumor growth and formation of lung cancer cells in xenograft SCID mice. Together, we provide a functional covalent conjugation of ND-paclitaxel, which can be delivered into lung carcinoma cells and preserves the anticancer activities on the induction of mitotic blockage, apoptosis and anti-tumorigenesis. Source

Pei T.-H.,National Chiao Tung University | Thiyagu S.,National Chung Hsing University | Pei Z.,National Chung Hsing University
Applied Physics Letters | Year: 2011

We fabricated large-area, vertically aligned silicon nanowire (SiNW) arrays on Si substrates employing catalytic etching on a polystyrene nanosphere template. The density of SiNWs was as high as 1010/cm2, and the bottom radii of SiNWs ranged between 30 and 60 nm. The reflection from the SiNW layer was approximately 0.1 over the spectral range of 300-800 nm for SiNWs longer than 750 nm. Effective medium theory was applied to explain this extremely low reflection, and it was confirmed that the incident light scatters randomly inside cone-like SiNWs, which lengthens the actual traveling path of light. © 2011 American Institute of Physics. Source

Chiu C.-H.,National Tsing Hua University | Chiu C.-H.,National Chiao Tung University | Jost L.,EcoMinga Foundation | Chao A.,National Tsing Hua University
Ecological Monographs | Year: 2014

Until now, decomposition of abundance-sensitive gamma (regional) phylogenetic diversity measures into alpha and beta (within- and between-group) components has been based on an additive partitioning of phylogenetic generalized entropies, especially Rao's quadratic entropy. This additive approach led to a phylogenetic measure of differentiation between assemblages: (gamma alpha)/gamma. We show both empirically and theoretically that this approach inherits all of the problems recently identified in the additive partitioning of non-phylogenetic generalized entropies. When within-assemblage (alpha) quadratic entropy is high, the additive beta and the differentiation measure (gammaalpha)/gamma always tend to zero (implying no differentiation) regardless of phylogenetic structures and differences in species abundances across assemblages. Likewise, the differentiation measure based on the phylogenetic generalization of Shannon entropy always approaches zero whenever gamma phylogenetic entropy is high. Such critical flaws, inherited from their non-phylogenetic parent measures (Gini-Simpson index and Shannon entropy respectively), have caused interpretational problems. These flaws arise because phylogenetic generalized entropies do not obey the replication principle, which ensures that the diversity measures are linear with respect to species addition or group pooling. Furthermore, their complete partitioning into independent components is not additive (except for phylogenetic entropy). Just as in the non-phylogenetic case, these interpretational problems are resolved by using phylogenetic Hill numbers that obey the replication principle. Here we show how to partition the phylogenetic gamma diversity based on Hill numbers into independent alpha and beta components, which turn out to be multiplicative. The resulting phylogenetic beta diversity (ratio of gamma to alpha) measures the effective number of completely phylogenetically distinct assemblages. This beta component measures pure differentiation among assemblages and thus can be used to construct several classes of similarity or differentiation measures normalized onto the range [0, 1]. We also propose a normalization to fix the traditional additive phylogenetic similarity and differentiation measures, and we show that this yields the same similarity and differentiation measures we derived from multiplicative phylogenetic diversity partitioning. We thus can achieve a consensus on phylogenetic similarity and differentiation measures, including N-assemblage phylogenetic generalizations of the classic Jaccard, Sørensen, Horn, and Morisita-Horn measures. Hypothetical and real examples are used for illustration. © 2014 by the Ecological Society of America. Source

Martin L.W.,University of Illinois at Urbana - Champaign | Chu Y.-H.,National Chiao Tung University | Ramesh R.,University of California at Berkeley | Ramesh R.,Lawrence Berkeley National Laboratory
Materials Science and Engineering R: Reports | Year: 2010

The growth and characterization of functional oxide thin films that are ferroelectric, magnetic, or both at the same time are reviewed. The evolution of synthesis techniques and how advances in in situ characterization have enabled significant acceleration in improvements to these materials are described. Methods for enhancing the properties of functional materials or creating entirely new functionality at interfaces are covered, including strain engineering and layering control at the atomic-layer level. Emerging applications of these functional oxides such as achieving electrical control of ferromagnetism and the future of these complex functional oxides is discussed. © 2010 Elsevier B.V. All rights reserved. Source

Hu S.-H.,University of Washington | Hu S.-H.,National Chiao Tung University | Gao X.,University of Washington
Journal of the American Chemical Society | Year: 2010

Compact nanostructures with highly integrated functionalities are of considerable current interest to drug delivery, multimodality imaging, and electronic devices. A key challenge, however, is how to combine individual components together without interfering or sacrificing their original electronic and optical properties. Here, we demonstrate a new class of nanocomposites with spatially separated functionalities. We further demonstrate magnetic field modulated imaging and an innovative application of this technology in cancer cell treatment, magnetolytic therapy, based on magnetically controlled mechanical damage to cell membranes. Source

Lin T.-Y.,National Chiao Tung University
Molecular BioSystems | Year: 2010

Thiol-disulfide exchange reactions between thiol-disulfide oxidoreductases (e.g. thioredoxin or Trx) and client proteins can obtain a rate several orders faster than those between chemical reagents (e.g. dithiothreitol) and client proteins. The active sites of these oxidoreductases are characterized by a CXXC motif. The XX dipeptide of Trx is GP. By altering the C-terminal X to A, K and D, it is shown that the P → K mutation confers the largest effect on the redox potential, which it elevated by 28 mV, while the P → D mutation displays the smallest variation. The change in pK a of the nucleophilic thiol also follows this trend. However, GK and GA react faster with thioredoxin reductase, exhibiting a rate rank of GK > GA > GP > GD, while the rates toward insulin and PDI follow the order GP > GA > GK > GD. The rate change spans two to three orders of magnitude. This work demonstrates that redox reactivity does not correlate simply with pK a and redox potential, but instead supports the important role of interaction between proteins in determining the fast reactivity and rate order of Trx. A reaction mechanism involving the transient formation of a Trx-protein binding complex is proposed for the oxidoreduction of protein thiols-disulfides. Furthermore, studies on insulin reduction show that Trx acts as an enzyme rather than a redox couple. These results provide explanations for the observed variations of the CXXC motif in PDI-like proteins as well as the conservation of the CXXC motif in Trx. © The Royal Society of Chemistry 2010. Source

Okuno M.,University of Tokyo | Hamaguchi H.-O.,University of Tokyo | Hamaguchi H.-O.,National Chiao Tung University
Optics Letters | Year: 2010

We have developed a multifocus confocal Raman microspectroscopic system for the fast multimode vibrational imaging of living cells. It consists of an inverted microscope equipped with a microlens array, a pinhole array, a fiber bundle, and a multichannel Raman spectrometer. Forty-eight Raman spectra from 48 foci under the microscope are simultaneously obtained by using multifocus excitation and image-compression techniques. The multifocus confocal configuration suppresses the background generated from the cover glass and the cell culturing medium so that high-contrast images are obtainable with a short accumulation time. The system enables us to obtain multimode (10 different vibrational modes) vibrational images of living cells in tens of seconds with only 1 mWlaser power at one focal point. This image acquisition time is more than 10 times faster than that in conventional singlefocus Raman microspectroscopy. © 2010 Optical Society of America. Source

Huang H.-C.,National University of Kaohsiung | Fang W.-C.,National Chiao Tung University
Sensors | Year: 2011

With the widespread use of identification systems, establishing authenticity with sensors has become an important research issue. Among the schemes for making authenticity verification based on information security possible, reversible data hiding has attracted much attention during the past few years. With its characteristics of reversibility, the scheme is required to fulfill the goals from two aspects. On the one hand, at the encoder, the secret information needs to be embedded into the original image by some algorithms, such that the output image will resemble the input one as much as possible. On the other hand, at the decoder, both the secret information and the original image must be correctly extracted and recovered, and they should be identical to their embedding counterparts. Under the requirement of reversibility, for evaluating the performance of the data hiding algorithm, the output image quality, named imperceptibility, and the number of bits for embedding, called capacity, are the two key factors to access the effectiveness of the algorithm. Besides, the size of side information for making decoding possible should also be evaluated. Here we consider using the characteristics of original images for developing our method with better performance. In this paper, we propose an algorithm that has the ability to provide more capacity than conventional algorithms, with similar output image quality after embedding, and comparable side information produced. Simulation results demonstrate the applicability and better performance of our algorithm. © 2011 by the authors. Source

Tiwari J.N.,Pohang University of Science and Technology | Tiwari R.N.,Toyota Technological Institute | Singh G.,National Chiao Tung University | Kim K.S.,Pohang University of Science and Technology
Nano Energy | Year: 2013

Continuous growth in global energy demand has sparked concerns about energy security and environmental sustainability. In the past two decades, attempts have been made in the development of innovative energy technologies. The direct methanol fuel cell (DMFC) is among the most promising alternative energy sources for the near future. Simple construction, compact design, high energy density and relatively high energy-conversion efficiency give the DMFC an advantage over other promising power sources in terms of portability. However, the translation of DMFCs into commercially successful products is precluded due to poor performance. In addition, low activity, poor durability and reliability and an expensive anode and cathode further discourage the application of DMFCs. In this regard, the present review article focuses on recent progress in the development of anode and cathode catalysts for DMFCs. The first part of the review discusses the recent developments in the synthesis of single-, double-, and multiple-component catalysts and new catalyst supports for anode electrodes. The section is followed by the chemical approaches employed to make alloys and composite catalysts, aiming to enhance their activity, reliability and durability for the methanol oxidation reaction. Finally, exciting new research that pushes the development of single-, double-, and multiple-component catalysts and new catalyst supports for cathode electrodes is introduced. In addition, size-, shape- and composition-dependent electrocatalysts that are advocated for methanol oxidation at the anode and oxygen reduction at the cathode are highlighted to illustrate the potential of the newly developed electrocatalysts for DMFC applications. Moreover, this article provides a comprehensive review of the experimental work that is devoted to understanding the fundamental problems and recent progress in the development of anode and cathode catalysts for DMFCs.© 2013 Elsevier Ltd. Source

Hung K.-C.,MediaTek Inc. | Lin D.W.,National Chiao Tung University
IEEE Transactions on Vehicular Technology | Year: 2010

In linear-minimum-mean-square-error (LMMSE) channel estimation for multicarrier systems, one needs to know the channel correlation function. This poses a problem for systems with a small number of pilots operating in time-varying channels. We propose to approximate the channel powerdelay profile (PDP) with a shape that can completely be described in two parameters, namely, the mean delay and the root-mean-square (RMS) delay spread. Furthermore, we develop a simple technique to estimate these delay parameters. The approximate PDP is then used to generate the LMMSE filter coefficients for data-subcarrier channel estimation. Mathematical expressions are derived that can be used to predict the accuracy of the various estimates, and they are verified by simulation. The proposed technique is applicable to both point-to-point communication and multiaccess communication where different users may experience different channel conditions. As a practical application, we also specialize the proposed technique to Mobile WiMAX signals and investigate the resulting performance. © 2009 IEEE. Source

Chang K.-H.,The Academy of Management | Wen T.-C.,National Chiao Tung University
Expert Systems with Applications | Year: 2010

Design Failure Mode and Effect Analysis (DFMEA) is the application of the Failure Mode and Effects Analysis (FMEA) method specifically to product design. DFMEA is not only an important risk assessment technique but also a major task for enterprises in implementing production management. The purpose is to ensure that the product can achieve its designed functions under specific operating conditions. Most current DFMEA methods use the Risk Priority Number (RPN) value to evaluate the risk of failure. However, conventional RPN methodology has the serious problem of measurement scales and loses some valued information, which experts have to provide. In order to improve the method of RPN evaluation, this paper proposes a novel technique, combining 2-tuple and the Ordered Weighted Averaging (OWA) operator for prioritization of failures in a product DFMEA. A case of the Color Super Twisted Nematic (CSTN) that has been drawn from a midsized manufacturing factory is presented to further illustrate the proposed approach. After comparing the result that was obtained from the proposed method with the other two listed approaches, it was found that the proposed approach can effectively solve the problem of measurement scales and has not lost any expert to provide the useful information. As a result, stability of the product and process can be assured. © 2009 Elsevier Ltd. All rights reserved. Source

Chen J.-K.,Tamkang University | Chen I.-S.,National Chiao Tung University
Expert Systems with Applications | Year: 2010

Due to economic pressures and declining birth rates, universities in Taiwan are seeking ways to evaluate and improve operational performance to acquire a competitive advantage to attract more students. However, current performance evaluation models have been criticized for two reasons. First, the measurement criteria currently used are not completely in accordance with the characteristics of different university types, research-intensive university, teaching-intensive university, and professional-intensive university. Second, the models assume independence of measured criteria. Nonetheless, in the real world, such measured criteria are seldom independent. To address these issues, we first reviewed the literature and interviewed Taiwanese higher education experts to integrate critical measurement criteria and develop an original performance appraisal system (OPAS). Next, we adapted a decision-making trial and evaluation laboratory (DEMATEL) method to present complex interdependent relationships and to construct a relation structure among measurement criteria for performance appraisal. A fuzzy analytic network process (FANP) was generated to address the dependence and feedback among each of the measurement criteria. Finally, we proposed a Pro-performance appraisal system (PPAS). This study offers a Pro-performance appraisal system (PPAS) to aid in future performance appraisals and improvements for all three university types. © 2009 Elsevier Ltd. All rights reserved. Source

MicroRNAs (miRNAs) play a critical role in down-regulating gene expression. By coupling with Argonaute family proteins, miRNAs bind to target sites on mRNAs and employ translational repression. A large amount of miRNA-target interactions (MTIs) have been identified by the crosslinking and immunoprecipitation (CLIP) and the photoactivatable-ribonucleoside-enhanced CLIP (PAR-CLIP) along with the next-generation sequencing (NGS). PAR-CLIP shows high efficiency of RNA co-immunoprecipitation, but it also lead to T to C conversion in miRNA-RNA-protein crosslinking regions. This artificial error obviously reduces the mappability of reads. However, a specific tool to analyze CLIP and PAR-CLIP data that takes T to C conversion into account is still in need. We herein propose the first CLIP and PAR-CLIP sequencing analysis platform specifically for miRNA target analysis, namely miRTarCLIP. From scratch, it automatically removes adaptor sequences from raw reads, filters low quality reads, reverts C to T, aligns reads to 3'UTRs, scans for read clusters, identifies high confidence miRNA target sites, and provides annotations from external databases. With multi-threading techniques and our novel C to T reversion procedure, miRTarCLIP greatly reduces the running time comparing to conventional approaches. In addition, miRTarCLIP serves with a web-based interface to provide better user experiences in browsing and searching targets of interested miRNAs. To demonstrate the superior functionality of miRTarCLIP, we applied miRTarCLIP to two public available CLIP and PAR-CLIP sequencing datasets. miRTarCLIP not only shows comparable results to that of other existing tools in a much faster speed, but also reveals interesting features among these putative target sites. Specifically, we used miRTarCLIP to disclose that T to C conversion within position 1-7 and that within position 8-14 of miRNA target sites are significantly different (p value = 0.02), and even more significant when focusing on sites targeted by top 102 highly expressed miRNAs only (p value = 0.01). These results comply with previous findings and further suggest that combining miRNA expression and PAR-CLIP data can improve accuracy of the miRNA target prediction. To sum up, we devised a systematic approach for mining miRNA-target sites from CLIP-seq and PAR-CLIP sequencing data, and integrated the workflow with a graphical web-based browser, which provides a user friendly interface and detailed annotations of MTIs. We also showed through real-life examples that miRTarCLIP is a powerful tool for understanding miRNAs. Our integrated tool can be accessed online freely at http://miRTarCLIP.mbc.nctu.edu.tw. Source

Hsiao C.-W.,Alpha Image Technology Corporation | Tsai W.-J.,National Chiao Tung University
IEEE Transactions on Circuits and Systems for Video Technology | Year: 2010

Multiple description (MD) video coding is one of the approaches that can be used to reduce the detrimental effects caused by transmission over error-prone networks. A number of approaches have been proposed for MD coding, where each provides a different tradeoff between compression efficiency and error resilience. This paper first presents two basic MD coding methods; one segments the video in the spatial domain, while the other in the frequency domain. Then a hybrid MD coding method is proposed. The hybrid MD encoder segments the video in both the spatial and frequency domains. In the case of data loss, the hybrid MD decoder takes advantage of the residual-pixel correlations in the spatial domain, and the coefficient correlations in the frequency domain, for error concealment. As a result, better error resilience can be achieved at high compression efficiency. The advantages of the proposed hybrid MD method are demonstrated in the contexts of descriptor loss in ideal channels and in packet-loss networks. © 2010 IEEE. Source

Huang H.L.,National Chiao Tung University
BMC bioinformatics | Year: 2012

Existing methods for predicting protein solubility on overexpression in Escherichia coli advance performance by using ensemble classifiers such as two-stage support vector machine (SVM) based classifiers and a number of feature types such as physicochemical properties, amino acid and dipeptide composition, accompanied with feature selection. It is desirable to develop a simple and easily interpretable method for predicting protein solubility, compared to existing complex SVM-based methods. This study proposes a novel scoring card method (SCM) by using dipeptide composition only to estimate solubility scores of sequences for predicting protein solubility. SCM calculates the propensities of 400 individual dipeptides to be soluble using statistic discrimination between soluble and insoluble proteins of a training data set. Consequently, the propensity scores of all dipeptides are further optimized using an intelligent genetic algorithm. The solubility score of a sequence is determined by the weighted sum of all propensity scores and dipeptide composition. To evaluate SCM by performance comparisons, four data sets with different sizes and variation degrees of experimental conditions were used. The results show that the simple method SCM with interpretable propensities of dipeptides has promising performance, compared with existing SVM-based ensemble methods with a number of feature types. Furthermore, the propensities of dipeptides and solubility scores of sequences can provide insights to protein solubility. For example, the analysis of dipeptide scores shows high propensity of α-helix structure and thermophilic proteins to be soluble. The propensities of individual dipeptides to be soluble are varied for proteins under altered experimental conditions. For accurately predicting protein solubility using SCM, it is better to customize the score card of dipeptide propensities by using a training data set under the same specified experimental conditions. The proposed method SCM with solubility scores and dipeptide propensities can be easily applied to the protein function prediction problems that dipeptide composition features play an important role. The used datasets, source codes of SCM, and supplementary files are available at http://iclab.life.nctu.edu.tw/SCM/. Source

Sun C.-C.,National Chiao Tung University
Expert Systems with Applications | Year: 2010

Multiple criteria decision-making (MCDM) research has developed rapidly and has become a main area of research for dealing with complex decision problems. The purpose of the paper is to explore the performance evaluation model. This paper develops an evaluation model based on the fuzzy analytic hierarchy process and the technique for order performance by similarity to ideal solution, fuzzy TOPSIS, to help the industrial practitioners for the performance evaluation in a fuzzy environment where the vagueness and subjectivity are handled with linguistic values parameterized by triangular fuzzy numbers. The proposed method enables decision analysts to better understand the complete evaluation process and provide a more accurate, effective, and systematic decision support tool. © 2010 Elsevier Ltd. All rights reserved. Source

Sha D.Y.,Chung Hua University | Lin H.-H.,National Chiao Tung University
Expert Systems with Applications | Year: 2010

Most previous research into the job-shop scheduling problem has concentrated on finding a single optimal solution (e.g., makespan), even though the actual requirement of most production systems requires multi-objective optimization. The aim of this paper is to construct a particle swarm optimization (PSO) for an elaborate multi-objective job-shop scheduling problem. The original PSO was used to solve continuous optimization problems. Due to the discrete solution spaces of scheduling optimization problems, the authors modified the particle position representation, particle movement, and particle velocity in this study. The modified PSO was used to solve various benchmark problems. Test results demonstrated that the modified PSO performed better in search quality and efficiency than traditional evolutionary heuristics. © 2009 Elsevier Ltd. All rights reserved. Source

Chen Y.-C.,Realtek Inc. | Su Yu.,National Chiao Tung University
IEEE Transactions on Wireless Communications | Year: 2010

This paper presents two analytic correlated multiple-input multiple-output (MIMO) block fading channel models and their time-variant extensions that encompass the popular Kronecker model and the more general Weichselberger model as special cases. Both static and time-variant models offer compact representations of spatial- and/or time-correlated channels. When the transmit antenna array is such that the associated MIMO channel has a small angle spread (AS), which occurs quite often in a cellular downlink, our models admit reduced-rank channel representations. They also provide compact channel state information (CSI) descriptions which are needed in feedback systems and in many post channel estimation applications. The latter has the important implication of reduced feedback channel bandwidth requirement and lower post-processing complexity. Based on one of the proposed channel models we present novel iterative algorithms for estimating static and time-variant MIMO channels. The proposed models make it natural to decompose each iteration of our algorithms into two successive stages that are responsible for estimating the correlation coefficients and the signal direction, respectively. Using popular industry-approved standard channel models, we verify through simulations that our algorithms yield good MSE performance which, in many practical cases, is better than that achievable by a conventional leastsquare estimator. The mean-squared error (MSE) performance of our estimators are analyzed and the resulting predictions are consistent with those estimated by simulations. © 2006 IEEE. Source

Chou C.-C.,National Taiwan University | Chou C.-C.,National Center for Research on Earthquake Engineering | Chen S.-Y.,National Chiao Tung University
Engineering Structures | Year: 2010

This study presents the experimental and finite element analysis results of a proposed steel buckling-restrained brace (BRB). The proposed BRB has two components: (1) a steel core plate that carries all axial forces during tension and compression, and (2) two identical restraining members that sandwich the core plate with fully tensioned high-strength A490 bolts to prevent core buckling. Instead of using unbonded material, a small air gap is provided between the core plate and the restraining members to allow for lateral expansion of the core plate under compression. Since two restraining members can be disassembled easily by removing the bolts, a damaged steel core can be replaced after a large earthquake. Thus, manufacturing new restraining members is not required. Four BRB subassemblages were tested to investigate the inelastic deformation capabilities and verify the stability predictions for the braces. Test results indicate that three BRBs with sufficient flexural rigidity of the restraining member develop (1) stable hysteretic responses up to core axial strains of 2.1%-2.6%, (2) maximum compressive loads of 1724-1951 kN (1.4-1.6 times the actual yield load), and (3) a cumulative plastic ductility that is much higher than that specified in AISC seismic provisions (2005). One BRB, intentionally designed with inadequate flexural rigidity of the restraining member, experienced global buckling as predicted. Nonlinear finite element analysis was conducted for each BRB for a correlation study. The objective of the analysis was to conduct a parametric study for different BRBs to further verify the effects of restraining member size, number of bolts, core plate length and cross-sectional area on buckling load evaluation. The design procedure for the sandwiched BRB was provided based on test and finite element analysis results. © 2010 Elsevier Ltd. Source

Peng W.-R.,National Chiao Tung University
Journal of Lightwave Technology | Year: 2010

In this paper, we characterize the impact of laser phase noise (PN) in direct-detection optical OFDM (DDO-OFDM) and identify its many differences from those in coherent optical OFDM (CO-OFDM). The analytical models for the diverse PN effects, including power degradation, phase rotation term (PRT), and inter-carrier interference (ICI), are given in terms of critical system parameters with or without the small PN assumption. In particular, the analytical upper-bound of the ICI power with a simple form is also provided. We also present a bit error rate (BER) estimation approach which is proven to be reliable for an optical signal-to-noise-ratio (OSNR) penalty lower than ∼2 dB. In addition, the PN tolerances, in terms of OSNR penalty, are also numerically analyzed and discussed with different QAM formats, data rates, laser linewdiths, and subcarrier numbers. © 2010 IEEE. Source

Sang T.-H.,National Chiao Tung University
IEEE Transactions on Signal Processing | Year: 2010

The self-duality of short-time Fourier transform (STFT) is an elegant property and is useful in shedding light on the construction of STFT and its resolution capability. In this paper, the discrete version of self-duality is studied, and the property is interpreted in the context of resolution capabilities of time frequency distributions. In addition, two applications are provided as showcases of these insights obtained from the interpretation. In the first application, the problem of STFT synthesis is considered, and self-duality serves as an important indication of whether the synthesis problem at hands is properly formulated. In the second application, a new kind of high-resolution time-frequency distribution is constructed based on the understandings obtained by contrasting two of the most popular time-frequency analysis tools, namely, the STFT and the Wigner distribution. Copyright © 2010 IEEE. Source

Kuo H.-Y.,National Chiao Tung University
International Journal of Engineering Science | Year: 2010

We propose a theoretical framework for evaluation of electrostatic potentials in an unbounded isotropic matrix containing a number of arbitrarily dispersed elliptic cylinders subjected to a remotely prescribed potential field. The inclusions could be homogeneous or confocally multicoated, and may have different sizes, aspect ratios and different conductivities. The approach is based on a multipole expansion formalism, together with a construction of consistency conditions and translation operators. This procedure generalizes the approach of the classic work of Rayleigh [1] for a periodic array of circular disks or spheres to an arbitrarily dispersion of elliptic cylinders. We combine the methods of complex potentials with a re-expansion formulae and the generalized Rayleigh's formualtion to obtain a complete solution of the many-inclusion problem. We show that the coefficients of field expansions can be written in the form of an infinite set of linear algebraic equations. Numerical results are presented for several configuarions. We further apply the obtained field solutions to determine the effective conductivity of the composite. © 2009 Elsevier Ltd. All rights reserved. Source

Liu S.-C.,National Tsing Hua University | Ke W.-L.,National Tsing Hua University | Yu J.-S.K.,National Chiao Tung University | Kuo T.-S.,National Taiwan Normal University | Tsai Y.-C.,National Tsing Hua University
Angewandte Chemie - International Edition | Year: 2012

Take five: A unique quintuply bonded dimolybdenum complex [Mo 2(μ-Li){μ-HC(N-2,6-Et 2C 6H 3) 2} 3] (see picture) was synthesized and characterized. The Mo-Mo interaction includes an unexpected bridging Li + ion. Calculations indicate the bridging Li + ion does not perturb the Mo-Mo bond length (2.0612(4) Å), but results in a relatively small effective Mo-Mo bond order of 3.67. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Jang W.-Y.,National Chiao Tung University | Kyriakides S.,University of Texas at Austin
International Journal of Mechanical Sciences | Year: 2015

Commonly used hexagonal honeycomb is manufactured by cold expansion of a laminate of thin metal foils that are bonded along periodically placed strips. The process results in nearly hexagonal cells with double walls in one direction, small rounding at the bent corners, and leaves behind residual stresses. This paper evaluates the effect of the expansion on the compressive response of the honeycomb. A finite element model of a characteristic cell is developed using shell elements and by applying to it the appropriate periodicity conditions. The model is first expanded mechanically producing the realistic geometry and changes to the mechanical properties of the material. The cell is subsequently compressed laterally leading first to buckling, followed by collapse by progressive folding, all similar to the behavior of ideal, stress free hexagonal honeycomb. The calculated buckling stress is about 10% higher than the ideal case, the collapse stress about 5% lower and the average crushing stress somewhat higher. In addition, the buckling and collapse stresses show some sensitivity to the size of periodic domain analyzed, as indeed was the case for the ideal case. © 2014 Elsevier Ltd. All rights reserved. Source

Wang C.-H.,National Chiao Tung University
International Journal of Production Research | Year: 2015

Diverse customer desires coupled with technological advances have forced companies to manufacture products with ultimate performance, low cost, high quality and much shorter time-to-market. Recently, the popularity of smart phones has given rise to seriously declined product sales of digital cameras. In this paper, a two-phase framework is presented to offer decision supports on developing next-generation cameras. In the phase of market segmentation, Kansei engineering is employed to capture customer perceptions of affective features. Then, rough set theory is conducted to generate decision rules for partitioning the whole market into the consumer segment and the professional segment, respectively. In the phase of product customisation, conjoint analysis is applied to extract customer preferences for functional features. Furthermore, Grey relational analysis is conducted to select the top three varieties with regard to two distinct segments. In particular, this paper is capable to help brand companies or camera manufacturers better capture customer perceptions and preferences for digital cameras, effectively perform market segmentation (based on affective features) and efficiently conduct product customisation (based on functional features). © 2014 Taylor & Francis. Source

Yeh C.-H.,Feng Chia University | Chen H.-Y.,Industrial Technology Research Institute of Taiwan | Chow C.-W.,National Chiao Tung University | Liu Y.-L.,Industrial Technology Research Institute of Taiwan
Optics Express | Year: 2015

To increase the traffic rate in phosphor-LED visible light communication (VLC), a multi-band orthogonal frequency division multiplexed (OFDM) modulation is first proposed and demonstrated. In the measurement, we do not utilize optical blue filter to increase modulation bandwidth of phosphor-LED in the VLC system. In this proposed scheme, different bands of OFDM signals are applied to different LED chips in a LED lamp, this can avoid the power fading and nonlinearity issue by applying the same OFDM signal to all the LED chips in a LED lamp. Here, the maximum increase percentages of traffic rates are 41.1%, 17.8% and 17.8% under received illuminations of 200, 500 and 1000 Lux, respectively, when the proposed three-band OFDM modulation is used in the VLC system. In addition, the analysis and verification by experiments are also performed. © 2015 Optical Society of America. Source

Chang Y.C.,National Chiao Tung University
Journal of the Air & Waste Management Association (1995) | Year: 2012

The mesostructured materials MCM-41 and SBA-15 were studied as possible supports of bromocresol green (BG) dye impregnation for the ammonia gas detection because of their large surface area, high regenerative property, and high thermal stability. X-ray diffraction, transmission electron microscopy, scanning electron microscope, and N2 adsorption analysis were used to characterize the prepared materials. These materials could sense ammonia via visible color change from yellowish-orange to blue color. The color change process of the nanostructured materials was fully reversible during 10 cyclic tests. The results indicated that the ammonia absorption responses of the two nanostructured materials were both very sensitive, and high linear correlation and high precision were achieved. As the gaseous ammonia concentrations were 50 and 5 ppmv, the response times for the SBA-15/BG were only 1 and 5 min, respectively. Moreover the BG dye-impregnated SBA-15 was less affected by the variation in the relative humidity. It also had faster response for the detection of NH3, as well as lower manufacturing price as compared to that of the dye-impregnated MCM-41. Such feature enables SBA-15/BG to be a very promising material for the detection of ammonia gas. Source

This study employed Rogers' model to compare the diffusion of digital terrestrial television with the diffusion of digital cable in Taiwan. A telephone survey, which yielded 753 valid questionnaires, was conducted to collect data. The results of this study show that the factors affecting the intention to adopt digital terrestrial television differed widely from those affecting the intention to adopt digital cable. The diffusion of digital cable was discovered to be generally congruent with the prediction of Rogers' model, while the diffusion of digital terrestrial television was not. This second finding reveals a limitation in Rogers' model, namely, its alleged pro-innovation bias. It may be that the respondents in this study looked favorably on digital cable because they considered it, and not digital terrestrial television, to be an inevitable technology. Furthermore, this study found that awareness played an important role in respondents' adoption of digital television. This study therefore suggests that, to accelerate digital conversion, Taiwan's government should establish policies to educate people about digital television. © 2013 Elsevier Ltd. All rights reserved. Source

Liu L.P.,Rutgers University | Kuo H.-Y.,National Chiao Tung University
International Journal of Solids and Structures | Year: 2012

Magnetoelectric coupling is of interest for a variety of applications, but is weak in natural materials. Strain-coupled fibrous composites of piezoelectric and piezomagnetic materials are an attractive way of obtaining enhanced effective magnetoelectricity. This paper studies the effective magnetoelectric behaviors of two-phase multiferroic composites with periodic array of inhomogeneities. For a class of microstructures called periodic E-inclusions, we obtain a rigorous closed-form formula of the effective magnetoelectric coupling coefficient in terms of the shape matrix and volume fraction of the periodic E-inclusion. Based on the closed-form formula, we find the optimal volume fractions of the fiber phase for maximum magnetoelectric coupling and correlate the maximum magnetoelectric coupling with the material properties of the constituent phases. Based on these results, useful design principles are proposed for engineering magnetoelectric composites. © 2012 Elsevier Ltd. All rights reserved. Source

Chang S.-W.,Academia Sinica, Taiwan | Chang S.-W.,National Chiao Tung University
Optics Express | Year: 2011

We develop a frequency-domain formulation in the form of generalized eigenvalue problems for reciprocal microlasers and nanolasers. While the goal is to explore the resonance properties of dispersive cavities, the starting point of our approach is the mode expansion of arbitrary current sources inside the active regions of lasers. Due to the Lorentz reciprocity, a mode orthogonality relation is present and serves as the basis to distinguish various cavity modes. This scheme can also incorporate the asymmetric Fano lineshape into the emission spectra of cavities. We show how to obtain the important parameters of laser cavities based on this formulation. The proposed approach could be an alternative to other computation schemes such as the finite-difference-time- domain method for reciprocal cavities. © 2011 Optical Society of America. Source

This work studies the influence of material coatings, especially combined natural and metamaterials, on the radiation properties of a practical dipole like antenna, represented by a slotted conducting sphere. The selected geometry allows an exact solution to the problem, and thus the development of exact expressions for the antenna parameters, like the radiated power and directivity. It is shown that for materials with combined positive and negative parameters, mode resonances can occur at thinner coatings, the thickness of which can be made diminishingly small by proper selection of coating parameters. In particular, at these resonances the antenna directivity, while being finite, becomes independent of the antenna size and coating parameters. Source

Chi T.S.,National Chiao Tung University
The Journal of the Acoustical Society of America | Year: 2012

Spectro-temporal modulations of speech encode speech structures and speaker characteristics. An algorithm which distinguishes speech from non-speech based on spectro-temporal modulation energies is proposed and evaluated in robust text-independent closed-set speaker identification simulations using the TIMIT and GRID corpora. Simulation results show the proposed method produces much higher speaker identification rates in all signal-to-noise ratio (SNR) conditions than the baseline system using mel-frequency cepstral coefficients. In addition, the proposed method also outperforms the system, which uses auditory-based nonnegative tensor cepstral coefficients [Q. Wu and L. Zhang, "Auditory sparse representation for robust speaker recognition based on tensor structure," EURASIP J. Audio, Speech, Music Process. 2008, 578612 (2008)], in low SNR (≤ 10 dB) conditions. Source

Chang S.-W.,Academia Sinica, Taiwan | Chang S.-W.,National Chiao Tung University
IEEE Journal on Selected Topics in Quantum Electronics | Year: 2012

We present a convenient and self-consistent approach to calculate confinement factors and modal volumes of micro- and nanocavities, which are important for ultrasmall lasers and cavity quantum electrodynamics. This scheme does not rely on the numerical integrations related to optical fields and can avoid the indefinite dependence of physical quantities on integration regions. As a result of this built-in invariance to integration regions, the field representation of the confinement factor, in additional to its conventional expression, contains counter terms of volume and surface integrals, which cancel the effect of arbitrary integration volumes. This procedure is useful for small open cavities or those without sharp boundaries that distinguish cavity regions from free spaces. The uncertainty from different choices of integration regions can be thus eliminated. © 1995-2012 IEEE. Source

Jia W.-K.,National Chiao Tung University
IEEE Journal on Selected Areas in Communications | Year: 2014

This paper introduces a new scalable, efficient and stateless source routing scheme to ensure that unified unicast and multicast packets can be delivered in the Data Center Networks (DCNs). This scheme, called Code-Oriented eXplicit multicast (COXcast), is based on unicast and eXplicit multicast (Xcast). It constructs the unicast path and multicast tree by encoding the corresponding output port bitmap of each intermediate node. Using a common identifier and a node-specific key, so packets can be self-routed to multiple receivers without requiring header modification. In addition, intermediate switches/routers on the path/tree can be stateless. Compared to traditional source-based unicasting and explicit-based multicasting schemes, COXcast has lowered the processing cost, protocol overhead and delivery latency, while simplifying the deployment and management of a large number of medium-scale multicast groups, especially when applied to large-scale DCNs. © 2013 IEEE. Source

Chao P.C.-P.,National Chiao Tung University
IEEE Sensors Journal | Year: 2011

Recent advances in energy harvesting have been intensified due to urgent needs of portable, wireless electronics with extensive life span. The idea of energy harvesting is applicable to sensors that are placed and operated on some entities for a long time, or embedded into structures or human bodies, in which it is troublesome or detrimental to replace the sensor module batteries. Such sensors are commonly called self-powered sensors. The energy harvester devices are capable of capturing environmental energy and supplanting the battery in a standalone module, or working along with the battery to extend substantially its life. Vibration is considered one of the most high power and efficient among other ambient energy sources, such as solar energy and temperature difference. Piezoelectric and electromagnetic devices are mostly used to convert vibration to ac electric power. For vibratory harvesting, a delicately designed power conditioning circuit is required to store as much as possible of the device-output power into a battery. The design for this power conditioning needs to be consistent with the electric characteristics of the device and battery to achieve maximum power transfer and efficiency. This study offers an overview on various power conditioning electronic circuits designed for vibratory harvester devices and their applications to self-powered sensors. Comparative comments are provided in terms of circuit topology differences, conversion efficiencies and applicability to a sensor module. © 2011 IEEE. Source

Chow C.W.,National Chiao Tung University | Yeh C.H.,Industrial Technology Research Institute of Taiwan
Optics Express | Year: 2011

Long-reach passive optical network (LR-PON) is considered as a promising technology towards higher capacity and extended coverage optical system. We propose and demonstrate a LR-PON with the capability of Rayleigh backscattering (RB) noise mitigation. By using the upstream signal wavelength-transition generated by a dual-parallel Mach-Zehnder modulator (DP-MZM) based colorless optical networking unit (ONU), the spectral overlap among the upstream signal and the RB noises can be minimized. Hence, due to the achievement of effective RB mitigation, a 100 km LR-PON with a high split-ratio of 512 is demonstrated using 10 Gb/s non-return-to-zero (NRZ) downstream and 2.5 Gb/s NRZ upstream signals. Detail analysis of the wavelength-transition generation is presented. © 2011 Optical Society of America. Source

Chi P.-L.,National Chiao Tung University
IEEE Microwave and Wireless Components Letters | Year: 2012

A novel and miniaturized ring coupler capable of presenting arbitrary power divisions is proposed using the composite right/left-handed (CRLH) transmission lines. The unbalanced CRLH transmission lines that can be easily tailored to implement transmission lines of high or low Bloch impedance are applied to enhance the coupler's capability of arbitrary power divisions. To support our idea, a ring coupler that offers a 6 dB power division ratio and occupies only 44% of the conventional footprint was experimentally realized. Experimental results agree well with the simulation data. The proposed CRLH configuration demonstrates an alternative for implementing a compact ring coupler with arbitrary power division ratios. © 2012 IEEE. Source

Lin Y.-P.,National Chiao Tung University
IEEE Transactions on Signal Processing | Year: 2014

In this paper we consider variable-rate transmission for time-correlated MIMO (multi-input multi-output) channels with limited feedback. The number of bits loaded on each subchannel of the MIMO system is dynamically assigned according to the current channel condition and fed back to the transmitter. As the channel is time-correlated, bit loading is a vector signal that is also time-correlated. We propose to feedback bit loading using predictive coding, which is known to be a powerful quantization technique when the underlying signal is correlated in time. Assuming the channel is a first-order Gauss-Markov random process, we derive the predictor for the bit loading to be coded and analyze the corresponding prediction error variance when the channel is varying slowly. By exploiting the prediction error variance, we adapt the quantizer of the prediction error to have a smaller quantization error. Furthermore we show that the prediction error variance is proportional to a term that depends only on the time-correlation coefficient. This leads to the conclusion that, a codebook that is designed for a particular time correlation coefficient can be easily modified to a codebook for a different correlation coefficient without redesign. Simulations are presented to demonstrate that the proposed predictive coding can achieve a very good approximation of the desired transmission rate with a very low feedback rate. © 2014 IEEE. Source

Chen H.-C.,National Chiao Tung University
IEEE Transactions on Industrial Electronics | Year: 2014

Multiphase boost-type switch-mode rectifiers (SMRs) are often used to improve the efficiency of ac-dc conversion. In particular, the light-load efficiency can be increased by turning off some phases (i.e., phase-shedding operation). To keep the number of feedback signals fixed regardless of the topology phase number N, the interleaved current sensorless control (ICSC) with consideration of the phase-shedding operation is proposed in this paper. In ICSC, no current sensing is needed, and only input and output voltages are sensed. To demonstrate the proposed ICSC, a two-phase boost-type SMR is established for test, and the proposed ICSC is implemented in a field-programmable-gate-array-based system. The provided simulation and experimental results show good performance of the proposed ICSC. © 1982-2012 IEEE. Source

An effective diffusion model characterized by the technology-induced function diversification and cost reductions can be developed to reflect whether competition exists among multiple generations of technology and to interpret how price reductions stimulate consumption. New technology can enhance the production skill levels of LCD TV manufacturing, enabling successive generation of LCD TV to become larger-sized than the previous generation, reducing the overall cost in manufacturing process and resulting in the price reduction of LCD TVs. However, previous diffusive predictions of LCD TVs using conventional multi-generational models ignore the price effect on market potentials and generational substitutions, so a novel generation-specific multi-generational model for the first time incorporating heterogeneous price elasticity and consumer behaviors across various LCD TV sizes is constructed in this work. This study applies nonlinear least square method to simulate the parameters of our modified model and further compares the accuracy between our modified model and the existing models. Analytical results indicate that price reduction strongly correlates with LCD TV sales, implying that price reductions increase the market potential of each LCD TV generation. Our modified model performs superior to the conventional multi-generational model in terms of predicting future shipment orbits of 26-, 42-, and 46-in. LCD TVs. © 2013 Elsevier Ltd. All rights reserved. Source

Kuo J.-T.,Chang Gung University | Tsai C.-H.,National Chiao Tung University
Progress in Electromagnetics Research | Year: 2010

Generalized synthesis of the rat race ring coupler is developed with its four arms being allowed to have different characteristic impedances. The transmission line theory incorporated with the even-odd analysis is used to formulate the conditions for solving the circuit parameters. The solution shows that a rat race ring with a normalized area of 41.82% or 0.97λ-circumference can be achieved. Based on the solutions, simulated bandwidths of the new ring hybrids are reported. Two experimental circuits are measured for validation check. One uses stepped-impedance sections to realize the four arms for further size reduction. This circuit occupies only 13.12% of that of a conventional hybrid ring at 1GHz. It is believed that this implementation has the best size reduction for a microstrip ring hybrid in open literature. Measured scattering parameters show good agreement with the simulated results. Source

Cheng K.-H.,National Chiao Tung University | Tsai C.-C.,National Taiwan University of Science and Technology
Computers and Education | Year: 2014

Previous studies on augmented reality (AR) book learning have not provided an in-depth examination of the learning process, especially the interaction involved in child-parent shared book reading. Choosing an AR picture book to introduce its artistic work, this study aimed to explore how children and parents read the book through a series of analyses of behavioral patterns and cognitive attainment. A total of 33 child-parent pairs voluntarily participated in this study. Based on the indicators of the child-parent reading behaviors generated through content analysis, four behavioral patterns of AR picture book reading were identified: parent as dominator, child as dominator, communicative child-parent pair, and low communicative child-parent pair. The relationships between the child-parent reading behaviors and the children's cognitive attainment were further identified. Specifically, the child-parent behaviors of "parent as dominator" and "low communicative child-parent pair" were likely associated with simple description of the appearance of the artistic work by the children (low-level cognitive attainment). Conversely, the "child as dominator" and "communicative child-parent pair" behaviors resulted in the children explaining the artistic work they had seen or using their imagination to describe the content of the book (high-level cognitive attainment). © 2013 Elsevier Ltd. All rights reserved. Source

Wang C.-H.,National Chiao Tung University | Wang J.,National Chung Hsing University
Applied Soft Computing Journal | Year: 2014

In an era of global customization, dominating the majority market with a single product has become increasingly difficult and almost impossible for most companies. In contrast, they must provide various product varieties that attract diverse customers, particularly when acquiring distinct market segments. In practice, however, most companies cannot effectively reduce the gap between customer requirements and design characteristics, although this impacts the profitability and future growth of companies. Meanwhile, companies often get stuck in the trade-offs between enhancing product varieties and controlling manufacturing costs. Accordingly, this paper proposes a hybrid framework that combines fuzzy analytical hierarchy process (AHP), fuzzy Kano model with zero-one integer programming (ZOIP) to incorporate customer preferences and customer perceptions into the decision-making process of product configuration. Specifically, fuzzy AHP is used to extract customer preferences for core attributes while fuzzy Kano model is utilized to elicit customer perceptions of optional attributes. Finally, by virtue of ZOIP, the optimal product varieties (smart cameras) for distinct segments are determined by maximizing overall customer utility (OCU) and taking a firm's pricing policy into account. © 2014 Elsevier B.V. Source

Hu S.-K.,Kainan University | Lu M.-T.,National Chiao Tung University | Tzeng G.-H.,National Taipei University
Expert Systems with Applications | Year: 2014

In recent years, the smart phone equipped with advanced mobile applications such as convenient and easy access to the Internet has become an essential tool for the multitasking era, recently termed the M-era. How we can understand customers' needs and gaps and subsequently satisfy these needs and lessen these gaps by creating a high value-added product to enhance customer satisfaction and increase the benefits to, and the competitive advantage of, enterprises? This study proposes a smart phone improvement for promoting the product value to satisfy the customers' needs with a hybrid MCDM model, which combines the DANP (DEMATEL-based ANP) and VIKOR. The DANP can establish an influential network relation map (INRM) to analyze interrelationship among dimensions/criteria by using the DEMATEL technique and then can measure the influential weights by combining the basic concept of the ANP. Furthermore, the VIKOR combining the influential weights in each criterion can integrate into each dimensional and overall evaluation based on the INRM to improve the gaps for achieving aspiration level and can enhance their competitive advantage in the smart phone market by lessening the gaps related to mobile convenience, thus creating a high value-added mobile phone product. © 2014 Published by Elsevier Ltd. Source

Tsai S.-H.,National Chiao Tung University | Poor H.V.,Princeton University
IEEE Transactions on Signal Processing | Year: 2014

This paper investigates the power allocation problem for artificial noise (AN) secure precoding systems, and proposes closed-form solutions for maximizing the achievable secrecy rate. It is assumed that the transmitter knows the full channel information at the legitimate receiver, and knows only the statistics of the channel information at the eavesdropper. Lower bounds are derived for the secrecy rates in multiple-input single-output channels with single or multiple eavesdroppers and multiple-input multiple-output channels with multiple eavesdroppers. When the number of transmit antennas is sufficiently large, the bounds are tight, and closed-form solutions can be derived from these bounds. The analytical results suggest simple and yet informative solutions as follows: Let the numbers of receive antennas at the legitimate receiver and at the eavesdropper be Nr and Nr,e, respectively. The system should distribute Nr,e (Nr+Nr,e of the power to AN in the high SNR regime, and distribute zero power to AN in the low SNR regime; the rate loss due to the eavesdropper is -Nr log N r (Nr+Nr,e-Nr,e log Nr,e (Nr+Nr,e bits/sec/Hz in the high SNR regime and nearly negligible in the low SNR regime. The derived results also show that equal power and water-filling power allocations lead to similar solutions and rate loss. Simulation results corroborate the theoretical results. © 1991-2012 IEEE. Source

Li S.-C.S.,National Chiao Tung University
Computers in Human Behavior | Year: 2014

Tablet PCs, netbooks, and smart phones are similar to one another in that they possess the basic functions of computers, but they differ in what functions they emphasize. Rogers' diffusion of innovation model has been widely recognized as a powerful model for predicting technology adoption. This study adopted Rogers' model to examine the adoption intentions of the three new types of computers. A telephone survey was conducted to collect data. This study made 1757 telephone calls, from which 1100 valid calls were obtained, representing a response rate of 62.61%. The data analysis demonstrates that the findings are generally congruent with the predictions of Rogers' model. However, this study's results also reveal one limitation of Rogers' model, its pro-innovation bias, which explains why the diffusion of netbooks was incongruent with Rogers' model. © 2014 Elsevier Ltd. All rights reserved. Source

Chou C.-C.,National Taiwan University | Jao C.-K.,National Chiao Tung University
Earthquake Spectra | Year: 2010

This work investigates the seismic performance of rehabilitated steel moment connections using internal flange stiffeners (IFSs) welded to the face of a built-up box column and a beam flange inner side. The objective is to provide a rehabilitation scheme that excludes interference from the composite slab and story height limitation in an existing steel building. Five rehabilitated moment connections with different IFSs were tested according to AISC (2005) loading protocol to validate their cyclic performance. Two rehabilitated moment connections had excellent performance; no welded joint fractures were found in the connections with a drift in excess of 4%. The specimens were modeled using the computer program ABAQUS to further verify the effectiveness of the IFSs in transferring beam moments to a column and to investigate potential sources of connection failure. Design guidelines for the rehabilitation scheme are provided based on test and analytical results. © 2010, Earthquake Engineering Research Institute. Source

Tseng W.-H.,MediaTek Inc. | Fan C.-W.,MediaTek Inc. | Wu J.-T.,National Chiao Tung University
IEEE Journal of Solid-State Circuits | Year: 2011

A current-steering digital-to-analog converter (DAC) was fabricated using a 90 nm CMOS technology. Its dynamic performance is enhanced by adopting a digital random return-to-zero (DRRZ) operation and a compact current cell design. The DRRZ also facilitates a current-cell background calibration technique that ensures the DAC static linearity. The measured differential nonlinearity (DNL) is 0.5 LSB and the integral nonlinearity (INL) is 1.2 LSB. At 1.25 GS/s sampling rate, the DAC achieves a spurious-free dynamic range (SFDR) better than 70 dB up to 500 MHz input frequency. The DAC occupies an active area of 1100 × 750 μm2. It consumes a total of 128 mW from a 1.2 V and a 2.5 V supply. © 2011 IEEE. Source

Hung J.-C.,National Chin - Yi University of Technology | Lin C.-C.,National Chiao Tung University
Journal of Power Sources | Year: 2012

High aspect-ratio micro-flow channels on bipolar plates have the advantage of improving fuel cell performance. This study forms micro-flow channels with a high aspect ratio by increasing the forming pressure during the hydroforming process. This study designs and constructs a mechanical apparatus to enable a two-stage pressure increase in the hydroforming process. A high-pressure container is designed with three-layered tapered cylinders to sustain 1230.17 MPa working pressures, and a special seal component is designed to seal the high-pressure fluid and maintain high pressure. The feasibility of this high-pressure hydroforming technique is verified in preliminary tests. The investigation indicates that the aspect ratio of micro-flow channels can reach 0.468 when a hydrostatic pressure of 250 MPa is applied. Compared with the maximum aspect ratio of 0.31 formed using the traditional hydroforming process, the aspect ratio of micro-flow channels in this study was 51% higher, which enables the fuel cells with metallic bipolar plates to meet both performance and manufacturing requirements. © 2012 Elsevier B.V. All rights reserved. Source

Hsu C.-C.,National Chiao Tung University
Expert Systems with Applications | Year: 2012

The purpose of this study is to find the key factors influencing blog design, and explore the causal relationships between the criteria for each factor. Since design is a multiple criteria decision-making (MCDM) problem, this study adopts a model which is a hybrid of factor analysis and the Decision Making Trial and Evaluation Laboratory method (DEMATEL). The DEMATEL method is used to simplify and visualize the interrelationships between criteria in making a decision. This study found five core factors that influence blog design: visual clarity, interface and usability, content and searchability, programming, and sociability. In addition, the key criteria for each factor were identified and the impact-relation maps obtained. The results of this study can provide useful guidance to blog designers for developing better blog platforms. © 2011 Elsevier Ltd. All rights reserved. Source

Wang H.-H.,National Chiao Tung University | Boukamp F.,RMIT University
Journal of Computing in Civil Engineering | Year: 2011

Job hazard analysis (JHA) is a process of identifying potential hazards for each step of an activity and proposing safety rules to prevent potential incidents related to these hazards. In the United States, the Occupational Safety and Health Administration (OSHA) recommends performing JHA for construction activities to highlight and react to potential hazards. JHA commonly requires brainstorming sessions to identify steps and associated hazards within construction activities. A company's personnel involved in JHAs rely on their experience-and often also on the company's internal knowledge represented in the form of safety rules. However, the complexity and time-consuming nature of JHA prevent safety personnel from adjusting JHAs quickly when changes in the construction methods and the schedule are made. This paper presents a framework aiming to improve access to a company's JHA knowledge. The framework uses ontologies for structuring knowledge about activities, job steps, and hazards. It also includes an ontological reasoning mechanism for identifying safety rules applicable to given activities. The framework has been validated through several test cases using real JHA documents. The results of the validations are discussed, and conclusions for future research are drawn. © 2011 American Society of Civil Engineers. Source

Lin J.-S.,National Chiao Tung University
Expert Systems with Applications | Year: 2012

As the wafer size increases, the clustering phenomenon of defects becomes significant. In addition to clustered defects, various clustering patterns also influence the wafer yield. In fact, the recognition of clustering pattern usually exists fuzziness. However, the wafer yield models in previous studies did not consider the fuzziness of clustering pattern belonging to which shape in recognition. Therefore, the objective of this study is to develop a new fuzzy variable of clustering pattern (FVCP) by using fuzzy logic control, and predict the wafer yield by using back-propagation neural network (BPNN) incorporating ant colony optimization (ACO). The proposed method utilizes defect counts, cluster index (CI), and FVCP as inputs for ACO-BPNN. A simulated study is utilized to demonstrate the effectiveness of the proposed model. © 2011 Elsevier Ltd. All rights reserved. Source

Wang Y.-L.,Kainan University | Tzeng G.-H.,Kainan University | Tzeng G.-H.,National Chiao Tung University
Expert Systems with Applications | Year: 2012

When consumers purchase products, they will consider the brand first, because it indirectly leads consumers to associate the products with the quality, functions, and the design. Based on the smiling curve, it showed enhancing the marketing or R&D will create value-added to the products or brands. Thus, this study intended to use brand marketing to create brand value. However, there are many criteria among the strategies, and they are interrelated. Therefore, this study utilized the MCDM model combining DEMATEL with ANP and VIKOR methods to clarify the interrelated relationships of brand marketing and find the problems or gaps; then, evaluated the situation to reduce the gaps in order to achieve the aspired levels and rank the priorities in brand marketing strategies, we also evaluated the customer's satisfaction of brand marketing by three electronic manufacturing companies in Taiwan. As the empirical results, value pricing is the most important factor, followed by consumer's price perception and perceived quality while showed the highest satisfaction of brand marketing was in F2 company. The results of this paper will provide the enterprises with a reference for planning brand marketing. © 2011 Elsevier Ltd. All rights reserved. Source

A class of thermal stable of green-emitting phosphors Ba(3)Y(PO(4))(3):Ce(3+),Tb(3+) (BYP:Ce(3+),Tb(3+)) and red-emitting phosphors Ca(3)Y(AlO)(3)(BO(3))(4):Eu(3+) (CYAB:Eu(3+)) for white-light fluorescent lamps were synthesized by high temperature solid-state reaction. We observed a decay of only 3% at 150 °C for BYP:0.25Ce3+,0.25Tb3+ (3% for LaPO4:Ce(3+),Tb(3+)), and a decay of 4% for CYAB:0.5Eu(3+) (7% for Y(2)O(3):Eu(3+), 24% for Y(2)O(2)S:Eu(3+)). The emission intensity of composition-optimized Ba(3)(Y(0.5)Ce(0.25)Tb(0.25))(PO(4))(3) is 70% of that of commercial LaPO(4):Ce(3+),Tb(3+) phosphors, and the CIE chromaticity coordinates are found to be (0.323, 0.534). The emission intensity of Ca(3)(Y(0.5)Eu(0.5))(AlO)(3)(BO(3))(4) is 70% and 83% of those of Y(2)O(3):Eu(3+) and Y(2)O(2)S:Eu(3+) phosphors, respectively, and the CIE chromaticity coordinates are redder (0.652, 0.342) than those of Y(2)O(3):Eu(3+) (0.645, 0.347) and Y(2)O(2)S:Eu(3+) (0.647, 0.343). A white-light fluorescent lamp is fabricated using composition-optimized Ba(3)(Y(0.5)Ce(0.25)Tb(0.25))(PO(4))(3) and Ca(3)(Y(0.5)Eu(0.5))(AlO)(3)(BO(3))(4) phosphors and matching blue-emitting phosphors. The results indicate that the quality of the brightness and color reproduction is suitable for application in shortwave UV fluorescent lamps. The white-light fluorescent lamp displays CIE chromaticity coordinates of x = 0.33, y = 0.35, a warm white light with a correlated color temperature of 5646 K, and a color-rendering index of Ra = 70. Source

Lin C.-C.,National Chiao Tung University | Deng D.-J.,National Changhua University of Education
IEEE Transactions on Industrial Electronics | Year: 2015

Vehicular ad hoc networks (VANETs) help improve traffic safety and lessen traffic congestion. Roadside units (RSUs) play a key role in serving as the event and data broker in the form of vehicle-to-infrastructure communication to supply wireless and mobile vehicle-to-vehicle communication. Recently, hybrid VANET-sensor networks have attracted much attention as events are detected by sensor nodes and are spread to a wider area via VANETs, in which the number of RSUs is restricted due to high cost. This paper investigates the problem of minimizing the total cost of deploying RSUs and sensor nodes along the two sides and the median island of a two-lane road to cover the whole road, represented as a grid, and to form a connected VANET-sensor network. This problem is NP-complete by reduction to the NP-complete placement problem for a single-lane road. Therefore, this paper formulates the problem as an integer linear program and then proposes a center particle swarm optimization approach, in which a center particle is adopted for increasing the convergence speed. Additionally, a theoretical analysis for the approach is provided. Experimental results show that the approach can perform well for moderate-sized problems. © 1982-2012 IEEE. Source

Yeh C.-H.,Industrial Technology Research Institute of Taiwan | Chow C.-W.,National Chiao Tung University | Pan C.-L.,National Tsing Hua University
Laser Physics Letters | Year: 2011

In this investigation, we propose and demonstrate a stable and wavelength-tunable erbium-doped fiber (EDF) ring laser scheme with external-injected Fabry-Perot laser diode (FP-LD) technology, in single-longitudinal-mode (SLM) output behavior. Here, the output power and side-mode suppression ratio (SMSR) of the proposed laser scheme can be obtained between -3.9 and 1.3 dBm and 30.1 and 50.5 dB in the operating wavelengths of 1523.65 and 1561.50 nm with 1.12 nm tuning step, respectively, according to the output mode-spacing of FP-LD used. Besides, the lasing stabilities of output power and wavelength are also investigated and discussed. © 2011 by Astro Ltd., published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA. Source

A rigorous but yet highly accurate and efficient numerical treatment of plane wave scattering by T-shaped planar corrugations through full-wave modal analysis is first presented in this paper, which entails the moment method using parallel-plate waveguide cavity Green's functions and a numerical spectral-domain Green's function for planar stratified media. Investigations in terms of both reflection-phase and dispersion diagrams are conducted. After validating with the commercial software package: CST Microwave Studio, this moment-method is in turn used to verify a formula derived by the transverse resonance technique (TRT) for the surface-wave propagation constant of corrugations in terms of the dispersion diagram. Correspondences between the reflection-phase and dispersion diagrams are then established by relating the high and low impedance frequencies in the former with the pass and stop bands of the latter. With the abovementioned formula, the way is paved for a novel derivation of explicit formulas for the reflection-phase of an incident plane wave impingent on the corrugations as closed-form analytic functions of the various parameters, even for oblique azimuth planes of incidence and for both TE and TM polarizations. Doing so, the high or low surface-impedance (AMC or AEC) properties of such corrugations can virtually be acquired instantly, thus providing incomparable speedup of the process of thorough reflection-phase characterization of AMC or high-impedance surfaces and soft surfaces, thus affording rapid designs of antennas and microwave devices that make use of them. © 2012 American Geophysical Union. All Rights Reserved. Source

Regulation of pre-mRNA splicing is achieved through the interaction of RNA sequence elements and a variety of RNA-splicing related proteins (splicing factors). The splicing machinery in humans is not yet fully elucidated, partly because splicing factors in humans have not been exhaustively identified. Furthermore, experimental methods for splicing factor identification are time-consuming and lab-intensive. Although many computational methods have been proposed for the identification of RNA-binding proteins, there exists no development that focuses on the identification of RNA-splicing related proteins so far. Therefore, we are motivated to design a method that focuses on the identification of human splicing factors using experimentally verified splicing factors. The investigation of amino acid composition reveals that there are remarkable differences between splicing factors and non-splicing proteins. A support vector machine (SVM) is utilized to construct a predictive model, and the five-fold cross-validation evaluation indicates that the SVM model trained with amino acid composition could provide a promising accuracy (80.22%). Another basic feature, amino acid dipeptide composition, is also examined to yield a similar predictive performance to amino acid composition. In addition, this work presents that the incorporation of evolutionary information and domain information could improve the predictive performance. The constructed models have been demonstrated to effectively classify (73.65% accuracy) an independent data set of human splicing factors. The result of independent testing indicates that in silico identification could be a feasible means of conducting preliminary analyses of splicing factors and significantly reducing the number of potential targets that require further in vivo or in vitro confirmation. Source

Hwang R.-B.,National Chiao Tung University
IEEE Transactions on Antennas and Propagation | Year: 2014

The plane wave scattering by 2-D gratings is studied by a rigorous mode-matching technique. Specifically, the grating considered in this work is made of periodically patterned graphene. Due to the 2-D periodicity, the electromagnetic fields in the uniform medium are expressed in terms of characteristic Floquet solutions, with each space harmonic representing a plane wave solution consisting of TE both TM and constituents. By imposing the boundary condition on the tangential components of the electromagnetic fields at the graphene interface via the conductivity tensor of graphene, one can set up an input-output relation expressed in terms of the generalized scattering matrix. For a planar multilayer structure consisting of a finite stack of 2-D graphene-based gratings, the overall scattering characteristics can be obtained by cascading each of the input-output relations of the 2-D grating successively. © 2014 IEEE. Source

Lee Y.-H.,National Taichung University of Education | Wu J.-Y.,National Chiao Tung University
Computers and Education | Year: 2013

Research showed distinct effects of different online activities on reading literacy or learning outcomes; however, no explanation about this link was provided. The current study investigated the effects of two genres of online reading activities on reading literacy based on knowledge of metacognitive strategies in a mediation analysis. Participants were 87,735 fifteen-year-old students (49.8% girls) across 15 regions in the PISA 2009 dataset. We divided online reading activities into social entertainment and information-seeking activities and controlled for gender, socioeconomic status, and the availability of Information and Communication Technologies (ICT) at home and at school. The indirect effects of knowledge of metacognitive strategies helped to explain why social entertainment and information-seeking activities would predict reading literacy differently. More frequent information-seeking activities predicted better knowledge of metacognitive strategies, which in turn predicted better reading literacy, while more frequent social entertainment activities predicted poorer knowledge of metacognitive strategies, which in turn led to poorer reading literacy. Suggestions were made to guide students in engaging in more online information-seeking reading activities, and incorporate instruction of metacognitive strategies for both online and offline reading, thereby improving students' reading literacy in both printed and digital formats. © 2013 Elsevier B.V. All rights reserved. Source

Ma Y.-S.,Yuanpei University | Sung C.-F.,Yuanpei University | Lin J.-G.,National Chiao Tung University
Journal of Hazardous Materials | Year: 2010

To establish an efficient oxidation process for carbofuran degradation, the effects of some operating parameters such as dosages of H 2O 2, Fe 2+ and initial carbofuran concentrations were observed during carbofuran degradation by the ultrasound process, Fenton process and a combined ultrasound/Fenton process. The degradation kinetics of carbofuran was also examined based on the experimental data. The results show that more than 99% of the carbofuran was degraded by the ultrasound/Fenton process within short reaction time periods. Increased dosages of H 2O 2 and Fe 2+ enhanced the degradation of carbofuran in the ultrasound and Fenton oxidation processes, but initial carbofuran concentrations decreased carbofuran degradation in both the Fenton and ultrasound/Fenton processes. The degradation kinetics of carbofuran by the three oxidation processes was found to be in accordance with first-order reaction kinetics. The results provide fundamental information about the treatment of carbofuran wastewater and/or other pesticides by the ultrasound/Fenton oxidation process. © 2010 Elsevier B.V. Source

Fuchs M.,National Chiao Tung University
Combinatorics Probability and Computing | Year: 2012

Simple families of increasing trees were introduced by Bergeron, Flajolet and Salvy. They include random binary search trees, random recursive trees and random plane-oriented recursive trees (PORTs) as important special cases. In this paper, we investigate the number of subtrees of size k on the fringe of some classes of increasing trees, namely generalized PORTs and d-ary increasing trees. We use a complex-analytic method to derive precise expansions of mean value and variance as well as a central limit theorem for fixed k. Moreover, we propose an elementary approach to derive limit laws when k is growing with n. Our results have consequences for the occurrence of pattern sizes on the fringe of increasing trees. © 2012 Cambridge University Press. Source

Honma S.,Kyushu Sangyo University | Hu J.-L.,National Chiao Tung University
Applied Energy | Year: 2014

Japan's energy security is more vulnerable today than it was before the Fukushima Daiichi nuclear power plant accident in March 2011. To alleviate its energy vulnerability, Japan has no choice but to improve energy efficiency. To aid in this improvement, this study compares Japan's energy efficiency at the industry level with that of other developed countries. We compute the total-factor energy efficiency (TFEE) of industries in 14 developed countries for 1995-2005 using data envelopment analysis. We use four inputs: labor, capital stock, energy, and non-energy intermediate inputs. Value added is the only relevant output. Results indicate that Japan can further optimize energy conservation because it experienced only a marginal decrease in the weighted TFEE, from 0.986 in 1995 to 0.927 in 2005. To improve inefficient industries, Japan should adapt energy conservation technologies from benchmark countries such as Germany, the United Kingdom, and the United States. © 2014 Elsevier Ltd. Source

Cheng C.-H.,National Taiwan Normal University | Chin A.,National Chiao Tung University
IEEE Electron Device Letters | Year: 2014

The power consumption of capacitor leakage current, increase of the capacitor aspect ratio, and lack of higher dielectric constant (κ) material are the difficult challenges to downscaling dynamic random access memory (DRAM). This letter reports a new one-transistor ferroelectric-MOSFET (1T FeMOS) device that displays DRAM functions of a 5 ns switching time, 10 12 on/off endurance cycles, and 30 times on/off retention windows at 5 s and 85°C. A simple 1T process and a considerably low OFF-state leakage of 3× 10-12A/μ m were achieved. This novel device was achieved by applying ferroelectric ZrHfO gate dielectric to a p-MOSFET, which is fully compatible with existing high-κ CMOS processing. © 1980-2012 IEEE. Source

Tsai Y.-T.,Yuan Ze University | Shih Z.-C.,National Chiao Tung University
ACM Transactions on Graphics | Year: 2012

With the increasing demands for photo-realistic image synthesis in real time, we propose a sparse multilinear model, which is named K-Clustered Tensor Approximation (K-CTA), to efficiently analyze and approximate large-scale multidimensional visual datasets, so that both storage space and rendering time are substantially reduced. K-CTA not only extends previous work on Clustered Tensor Approximation (CTA) to exploit inter-cluster coherence, but also allows a compact and sparse representation for high-dimensional datasets with just a few low-order factors and reduced multidimensional cluster core tensors. Thus, K-CTA can be regarded as a sparse extension of CTA and amultilinear generalization of sparse representation. Experimental results demonstrate that K-CTA can accurately approximate spatially varying visual datasets, such as bidirectional texture functions, view-dependent occlusion texture functions, and biscale radiance transfer functions for efficient rendering in real-time applications. © 2012 ACM. Source

Lin J.-S.,National Chiao Tung University
Applied Soft Computing Journal | Year: 2012

The clustering phenomenon of defects usually occurs in semiconductor manufacturing. However, previous studies did not pay much attention to the influence of clustering phenomenon for estimating fraction nonconforming of a wafer. Thus, this paper presents a systematic estimation model with considering relevant variables about clustering defects for fraction nonconforming of a wafer. The method combines back-propagation neural network (BPNN) with genetic algorithm (GA) to obtain an estimation model. In this study, GA aims to optimize the parameters of BPNN. Five relevant variables: number of defects (ND), squared coefficient of angle variation (SCV A) for defects, squared coefficient of distance variation (SCV D) for defects, defect cluster index (CI M), and the number of cluster groups (NCG) for defects by self-organized map (SOM) are utilized as inputs for GA-BPNN. Finally, a simulation case and a real-world case are used to confirm the effectiveness of proposed method. © 2012 Elsevier B.V. All rights reserved. Source

Wang C.-C.,National Chiao Tung University
Renewable and Sustainable Energy Reviews | Year: 2013

This study provides an overview about the two-phase heat transfer performance for HFO-1234yf which is made to substitute R-134a. Based on the limited information, it is found that the nucleate boiling heat transfer coefficient (HTC) and convective boiling HTC for HFO-1234yf are comparable to R-134a provided q<200 kW m-2. The critical heat flux for HFO-1234yf is about 20-40% lower than that of R-134a. For external condensation, the only database shows that the HTC between HFO-1234yf and R-134a is also negligible. However, it is found that the major thermophysical properties influencing condensing HTC suggest a lower HTC of HFO-1234yf. For in-tube condensation, it is found that the condensation HTCs for HFO-1234yf are inferior to those of R-134a, and the difference increases with the rise of vapor quality. The predictive correlations applicable for pressured drop for HFO-1234yf are not consistent, it is probably attributed to the difference in tube diameter in the publications. © 2012 Elsevier Ltd. Source

Moser S.M.,National Chiao Tung University
IEEE Transactions on Information Theory | Year: 2012

This paper investigates a channel model describing optical communication based on intensity modulation. It is assumed that the main distortion is caused by additive Gaussian noise, however, with a noise variance depending on the current signal strength. Both the high-power and low-power asymptotic capacities under simultaneously both a peak-power and an average-power constraint are derived. The high-power results are based on a new firm (nonasymptotic) lower bound and a new asymptotic upper bound. The upper bound relies on a dual expression for channel capacity and the notion of capacity-achieving input distributions that escape to infinity. The lower bound is based on a new lower bound on the differential entropy of the channel output in terms of the differential entropy of the channel input. The low-power results make use of a theorem by Prelov and van der Meulen. © 2006 IEEE. Source

This study develops two alternative models concerning job effectiveness, knowledge sharing, and their antecedents related to individuals' perception about their job effectiveness in a team. Model 1 of this study intends to be as parsimonious as theoretically justifiable. It posits that three dimensions of social capital - structural, relational, and cognitive social capital - simultaneously influence knowledge sharing and job effectiveness indirectly through the mediation of team commitment, while job effectiveness is also influenced by knowledge sharing. Based on Model 1, Model 2 further adds that knowledge sharing is influenced directly by three dimensions of social capital. The two models are tested by collecting data from professionals of virtual teams in high-tech industries. The test results support seven out of nine hypotheses in Model 2. Finally, managerial implications of the empirical findings are also discussed. © 2010 Elsevier Ltd. All rights reserved. Source

Sun Y.-C.,National Chiao Tung University | Chang Y.-J.,National Tsing Hua University
Language Learning and Technology | Year: 2012

This study examines how blogs and their interactive and collaborative features help academically-advanced graduate students process academic writing knowledge and make sense of their writer identity. Seven graduate students undertaking Master's level study in TESOL and Linguistics participated. The research questions are: (a) What kinds of writing-related topics do students blog about? (b) How do students' collaborative dialogues on blogs help them process and reconstruct knowledge about academic writing? (c) How do students' collaborative dialogues on blogs facilitate their negotiation of academic identities and construction of authorship? Open-coding and content analysis were conducted to inductively identify salient themes and patterns regarding students' learning and perception of their writer identities. The results suggest that the blog activity not only encourages students to actively and reflectively engage in knowledge sharing, knowledge generation, and the development of numerous strategies to cope with difficulties encountered in the learning process. Blogs also endow students with a sense of authorship as the writers of blog entries and, at the same time, provide a space for them to sort out what being an author entails, their purposes of writing, and their authority in writing. © 2012. Source

Chang C.-F.,National Chiao Tung University
Computers and Composition | Year: 2012

In the past few decades, the integration of virtual peer review has been implemented as an instructional procedure in second-language writing courses. Previous studies have been interested in comparing the effects of different communication modes and have endeavored to find out which mode is most effective. This paper reports a study examining how a combination of three modes (face-to-face, synchronous, and asynchronous CMC) influenced and might benefit students' peer review. The results indicate that the affordance of the three modes influenced students' task engagement, comment categories, and perception of peer review. The results further suggest that a combination of different modes in the multiple-draft process may benefit peer review and satisfy individual preferences towards the mode for peer review. The results imply that arranging various modes appropriately at different stages of drafting and customizing peer review training in using these modes may maximize the effects of peer review in the writing process. © 2012 Elsevier Inc. Source

Li S.-Y.,National Chiao Tung University
Applied Soft Computing Journal | Year: 2011

In this paper, a new fuzzy logic controller - fuzzy logic constant controller (FLCC) is introduced to chaotic signals controlling. The main ideas of the FLCC are described as follows: (1) proving the two chaotic systems are going to achieve asymptotically stable via Lyapunov direct method; (2) via detecting the sign of the errors, the appropriate fuzzy logic control scheme is operated; (3) choosing the upper bound and the lower bound of the error derivatives of the chaotic signals to be the consequent parts (corresponding controllers). Due to controllers in traditional method - derived by Lyapunov direct method, are always complicated, nonlinear form or the functions of errors, a new simplest controller - FLCC is presented in this paper to synchronize two chaotic signals. Through the FLCC, there are three main contributions can be obtained: (1) the mathematical models of the nonlinear chaotic systems can be unknown, all we have to do is capturing the signals of the unknown systems; (2) through the fuzzy logic rules, the strength of controllers can be adjusted via the corresponding membership functions (which are decided by the values of error derivatives); (3) by the FLCC, the chaotic system can be much more exactly and efficiently controlled to the trajectory of our goal than traditional ones. Three cases, original point, regular function and chaotic Qi system (with large values of initial conditions), are given to illustrate the effectiveness of our new FLC. © 2011 Elsevier B.V. All rights reserved. Source

Kim Y.,Chung - Ang University | Lai M.-C.,National Chiao Tung University
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2012

An inextensible vesicle under shear flow experiences a tank-treading motion on its membrane if the viscosity contrast between the interior and exterior fluids is small. Above a critical threshold of viscosity contrast, the vesicle undergoes a tumbling bifurcation. In this paper, we extend our previous work to the case of different viscosity and investigate the transition between the tank-treading and tumbling motions in detail. The present numerical results are in a good agreement with other numerical and theoretical studies qualitatively. In addition, we study the inertial effect on this transition and find that the inertial effect might inhibit the tumbling motion in favor of the tank-treading motion, which is observed recently in the literature. The critical viscosity contrast for the transition to the tumbling motion usually increases as the reduced area increases in the Stokes regime. However, we surprisingly observe that the critical viscosity contrast decreases as the reduced area increases to some point in the flow of slightly higher Reynolds number. Our numerical result also shows that the inertial effect has stronger inhibition to tumbling motion when the reduced area is small. © 2012 American Physical Society. Source

Lo J.-J.,Chung Hua University | Chan Y.-C.,Chung Hua University | Yeh S.-W.,National Chiao Tung University
Computers and Education | Year: 2012

This study developed an adaptive web-based learning system focusing on students' cognitive styles. The system is composed of a student model and an adaptation model. It collected students' browsing behaviors to update the student model for unobtrusively identifying student cognitive styles through a multi-layer feed-forward neural network (MLFF). The MLFF was adopted because of its ability on imprecise or incompletely understood data, ability to generalize and learn from specific examples, ability to be quickly updated with extra parameters, and speed in execution making them ideal for real time applications. The system then adaptively recommended learning content presented with a variety of content and interactive components through the adaptation model based on the student cognitive style identified in the student model. The adaptive web interfaces were designed by investigating the relationships between students' cognitive styles and browsing patterns of content and interactive components. Training of the MLFF and an experiment were conducted to examine the accuracy of identifying students' cognitive styles during browsing with the proposed MLFF and the impact of the proposed adaptive web-based system on students' engagement in learning. The training results of the MLFF showed that the proposed system could identify students' cognitive styles with high accuracy and the temporal effects should be considered while identifying students' cognitive styles during browsing. Two factors, the acknowledgment of students' cognitive styles while browsing and the existence of adaptive web interfaces, were used to assign three classes of college freshmen into three groups. The experimental results revealed that the proposed system could have significant impacts on temporal effects on students' engagement in learning, not only for students with cognitive styles known before browsing, but also for students with cognitive styles identified during browsing. The results provide evidence of the effectiveness of the adaptive web-based learning system with students' cognitive styles dynamically identified during browsing, thus validating the research purposes of this study. © 2011 Elsevier Ltd. All rights reserved. Source

Huang S.K.,National Chiao Tung University
Corporate Social Responsibility and Environmental Management | Year: 2013

This study explores the relationship between CEO demographic characteristics and consistency in corporate social responsibility (CSR) performance among firms. The sample is based on results from major ranking agencies between 2005 and 2010. A total of 661 firms were included in the sample with 392 observations in total. The results indicate that firms' CSR performance, as measured by the consistency of their CSR rankings, is associated with their CEOs' educational specializations in Master's-level business administration (MBA) and science (MSc). In addition, CEO tenure and gender are shown to affect firms' CSR performance. Furthermore, a firm's number of employees also has a significant relationship with its CSR performance. The results are encouraging for supporting universities' efforts to integrate CSR issues into their curricula. © 2012 John Wiley & Sons, Ltd and ERP Environment. Source

Li L.-B.,Nankai University | Hu J.-L.,National Chiao Tung University
Energy Policy | Year: 2012

Most existing energy efficiency indices are computed without taking into account undesirable outputs such as CO 2 and SO 2 emissions. This paper computes the ecological total-factor energy efficiency (ETFEE) of 30 regions in China for the period 2005-2009 through the slack-based model (SBM) with undesirable outputs. We calculate the ETFEE index by comparing the target energy input obtained from SBM with undesirable outputs to the actual energy input. Findings show that China's regional ETFEE still remains a low level of around 0.600 and regional energy efficiency is overestimated by more than 0.100 when not looking at environmental impacts. China's regional energy efficiency is extremely unbalanced: the east area ranks first with the highest ETFEE of above 0.700, the northeast and central areas follow, and the west area has the lowest ETFEE of less than 0.500. A monotone increasing relation exists between the area's ETFEE and China's per capita GDP. The truncated regression model shows that the ratio of R&D expenditure to GDP and the degree of foreign dependence have positive impacts, whereas the ratio of the secondary industry to GDP and the ratio of government subsidies for industrial pollution treatment to GDP have negative effects, on the ETFEE. © 2012 Elsevier Ltd. Source

Tsai W.-J.,National Chiao Tung University
IEEE Transactions on Circuits and Systems for Video Technology | Year: 2010

Transmission of compressed video signals over error-prone networks exposes the information to losses and errors. To reduce the effects of these losses and errors, this paper presents a joint spatial-temporal estimation method which takes advantages of data correlation in these two domains for better recovery of the lost information. The method is designed for the hybrid multiple description coding which splits video signals along spatial and temporal dimensions. In particular, the proposed method includes fixed and content-adaptive approaches for estimation method selection. The fixed approach selects the estimation method based on description loss cases, while the adaptive approach selects the method according to pixel gradients. The experimental results demonstrate that improved error resilience can be accomplished by the proposed estimation method. © 2006 IEEE. Source

Lin Y.-M.,Industrial Technology Research Institute of Taiwan | Tien P.-L.,National Chiao Tung University
IEEE Journal on Selected Areas in Communications | Year: 2010

In this paper, we propose a novel architecture for next-generation orthogonal frequency division multiple access (OFDMA)-based passive optical networks (PON's), referred to as ROFPON. Besides carrying local broadband OFDMA data, ROFPON seamlessly supports radio-over-fiber (RoF) transports between the central office and multiple remote antennas at end users without using costly WDM lasers. We analytically and experimentally study the receiver sensitivity to OFDMA signals and the radio frequency (RF) signal's performance. By corroborating simulation results with experimental results, we discuss the determination of crucial system parameters, such as the optimal broadband-to-radio power ratio, and the exploitation of a notch filter for removing RF interference. Experimental results show that the integrated 10 Gb/s OFDMA and three 20 MHz RF signals are successfully transported both downstream and upstream over a 20 km single-mode-fiber PON. Finally, experimental results demonstrate that QPSK-encoded WiMAXformat RF signals are transmitted/relayed upstream with E-O-E conversion at each optical network unit (ONU), and received error-free at the optical line terminal after cascading 32 ONU's. © 2010 IEEE. Source

Yeh C.H.,Industrial Technology Research Institute of Taiwan | Chow C.W.,National Chiao Tung University
Laser Physics Letters | Year: 2010

In this paper, a broadband wavelength-tunable erbiumdoped fiber (EDF) ring laser with single longitudinal mode (SLM) output achieving 82.6 nm lasing bandwidth from 1481.0 to 1563.6 nm is proposed and experimentally demonstrated. For the proposed laser scheme, the S- and C-band erbium-doped fiber amplifiers (EDFAs) in parallel structure are used to serve as the gain medium for broadband wavelength tuning. Furthermore, we use a saturable-absorber filter (SAF) inside the fiber cavity to serve as a narrow band filter to guarantee a SLM operation. Besides, the performance of output power, wavelength, side-mode suppression ratio (SMSR) and stability are also analyzed and discussed. © 2010 by Astro Ltd. Source

Chen J.-K.,Tamkang University | Chen I.-S.,National Chiao Tung University
Expert Systems with Applications | Year: 2010

Increasing numbers of Taiwanese higher education institutes are pursuing innovation operation. However, these institutes generally rely greatly on academic research to evaluate innovation performance. Nevertheless, the performance of innovation may be affected by numerous factors that are often beyond the scope of a single academic study. Thus, to address this concern, this paper constructs an innovation support system (ISS) for Taiwanese higher education institutes to comprehensively evaluate their innovation performance. Previous research often evaluates performance by independently considering a number of criteria. However, this assumption of independence does not model the so-called "real world"; thus, we present a novel conjunctive multiple criteria decision-making (MCDM) approach that addresses dependent relationships among each measurement criteria. As such, we utilize a decision-making trial and evaluation laboratory (DEMATEL), a fuzzy analytical network process (FANP), and a technique for order preference by similarity to an ideal solution (TOPSIS) forming order to develop an innovation support system (ISS) that considers the interdependence and the relative weights of each measurement criterion. © 2009 Elsevier Ltd. All rights reserved. Source

Liu Y.-S.,Changshu Institute of Technology | Chen Y.-C.,National Chiao Tung University
Applied Physics Letters | Year: 2011

Using a first-principles approach, we investigate the quantum cooling effects in single-molecule junctions. In comparison with the unsubstituted butanethiol single-molecule junction as a refrigerator, the amino-substituted butanethiol single-molecule junction shows significant enhancement in the coefficient of performance (COP). The enhancement is attributed to the appearance of new states in the neighborhood of chemical potentials due to amino substitution. The COP of butanethiol refrigerator can be improved further by the gate voltages. © 2011 American Institute of Physics. Source

Laird D.A.,Iowa State University | Chang C.-W.,National Chiao Tung University
Soil and Tillage Research | Year: 2013

Here we evaluate the impact of 19 years of either zero or approximately 90% removal of above ground crop residue on soil quality. The 0-5, 5-15, and 15-30. cm soil depths of Waukegan silt loam (Typic Hapludoll) from east-central Minnesota were sampled from plots after 12 and 7 years of maize and soybean cropping, respectively. On average for the 0-5 and 5-15. cm depths, soil organic C was 12% less, total N was 12.6% less, N mineralization potential was 27.7% less, cation exchange capacity was 7.3% less, macro aggregation was 13.0% less, and total respiration was 12.3% less for plots with residue harvesting relative to plots where residue was not harvested. Minimal impacts of residue harvesting were apparent for the 15-30. cm soil samples, except N mineralization potential which was 28% lower for plots with residue harvesting. Declines in soil quality indicators due to residue harvesting were only slightly less severe for no-tillage plots relative to chisel and moldboard plow tillage plots. We conclude that harvesting 90% of above ground residue for 19 years resulted in substantial degradation of soil quality, and that the impact on N mineralization potential was substantially larger than the loss of total N, suggesting that labile organic N was selectively depleted. We also conclude that stover harvesting for bioenergy production could cause similar degradation of soil quality unless management practices that increase C inputs to soils are also implemented. © 2013 Elsevier B.V. Source

Bessho T.,Ecole Polytechnique Federale de Lausanne | Zakeeruddin S.M.,Ecole Polytechnique Federale de Lausanne | Yeh C.-Y.,National Chung Hsing University | Diau E.W.-G.,National Chiao Tung University | Gratzel M.,Ecole Polytechnique Federale de Lausanne
Angewandte Chemie - International Edition | Year: 2010

To dye for: A porphyrin chromophore, which is integrated into a donor-acceptor dye as a π-conjugated bridge (see picture), exhibits an unprecedented efficiency of 11 □ % when used as a photosensitizer in a double-layer TiO2 film. A greatly enhanced photovoltaic performance is observed when the porphyrin dye is cosensitized with a metal-free dye that has a complementary spectral response. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Cheng C.H.,National Taiwan Normal University | Chin A.,National Chiao Tung University
IEEE Electron Device Letters | Year: 2014

Power consumption is the most difficult challenge for CMOS integrated circuits. Here, we demonstrate experimentally a novel steep turn-on pMOSFET for low-voltage operation for the first time, which exhibits 5-60 mV/decade SS, wide voltage range for SS <60~ mV decade sturdy < 60~ mV decade SS at 85̂ C, faster transistor turn-on at above threshold voltage, and lower off-state leakage by greater than three orders of magnitude. Such improved leakage current is crucial to decrease the off-state leakage current in sub-1X nm CMOS. This was achieved using ferroelectric high-κ ZrHfO gate dielectric pMOSFET. © 2014 IEEE. Source

Chen S.-K.,National Chiao Tung University
Computers in Human Behavior | Year: 2012

Studies of correlations between Internet use and psychological well-being (PW) have produced mixed results. The present study used a latent profile analysis to distinguish among populations in terms of PW profiles, and then used a multinomial logistic regression to determine how online entertainment, social use, problematic Internet use (PIU), and gender predicted each latent PW profile. The initial sample consisted of 757 Taiwanese college freshmen. Four ordered latent groups were established as follows: good PW, normative, minor-disadvantageous, and severe-disadvantageous. No latent PW profile stability was found in subsequent years: three groups (normative, minor-disadvantageous and severe-disadvantageous) emerged in Year 2, and only one group emerged in Year 3. The results indicate (a) no relationship between PW and online entertainment or gender, (b) greater PIU increased the likelihood of disadvantageous PW and decreased the probability of good PW, and (c) greater use of online resources for social purposes was related to increased probability of a participant being in the good PW group, but not associated with fewer PW problems. © 2012 Elsevier Ltd. All rights reserved. Source

Huang K.Y.,Yuan Ze University | Huang K.Y.,Academia Sinica, Taiwan | Huang K.Y.,National Chiao Tung University
Database : the journal of biological databases and curation | Year: 2014

Protein phosphorylation catalyzed by kinases plays crucial roles in regulating a variety of intracellular processes. Owing to an increasing number of in vivo phosphorylation sites that have been identified by mass spectrometry (MS)-based proteomics, the RegPhos, available online at http://csb.cse.yzu.edu.tw/RegPhos2/, was developed to explore protein phosphorylation networks in human. In this update, we not only enhance the data content in human but also investigate kinase-substrate phosphorylation networks in mouse and rat. The experimentally validated phosphorylation sites as well as their catalytic kinases were extracted from public resources, and MS/MS phosphopeptides were manually curated from research articles. RegPhos 2.0 aims to provide a more comprehensive view of intracellular signaling networks by integrating the information of metabolic pathways and protein-protein interactions. A case study shows that analyzing the phosphoproteome profile of time-dependent cell activation obtained from Liquid chromatography-mass spectrometry (LC-MS/MS) analysis, the RegPhos deciphered not only the consistent scheme in B cell receptor (BCR) signaling pathway but also novel regulatory molecules that may involve in it. With an attempt to help users efficiently identify the candidate biomarkers in cancers, 30 microarray experiments, including 39 cancerous versus normal cells, were analyzed for detecting cancer-specific expressed genes coding for kinases and their substrates. Furthermore, this update features an improved web interface to facilitate convenient access to the exploration of phosphorylation networks for a group of genes/proteins. Database URL: http://csb.cse.yzu.edu.tw/RegPhos2/ Source

Chen P.-S.,Indiana University | Chen L.S.,Indiana University | Fishbein M.C.,University of California at Los Angeles | Lin S.-F.,Indiana University | And 2 more authors.
Circulation Research | Year: 2014

Autonomic nervous system activation can induce significant and heterogeneous changes of atrial electrophysiology and induce atrial tachyarrhythmias, including atrial tachycardia and atrial fibrillation (AF). The importance of the autonomic nervous system in atrial arrhythmogenesis is also supported by circadian variation in the incidence of symptomatic AF in humans. Methods that reduce autonomic innervation or outflow have been shown to reduce the incidence of spontaneous or induced atrial arrhythmias, suggesting that neuromodulation may be helpful in controlling AF. In this review, we focus on the relationship between the autonomic nervous system and the pathophysiology of AF and the potential benefit and limitations of neuromodulation in the management of this arrhythmia. We conclude that autonomic nerve activity plays an important role in the initiation and maintenance of AF, and modulating autonomic nerve function may contribute to AF control. Potential therapeutic applications include ganglionated plexus ablation, renal sympathetic denervation, cervical vagal nerve stimulation, baroreflex stimulation, cutaneous stimulation, novel drug approaches, and biological therapies. Although the role of the autonomic nervous system has long been recognized, new science and new technologies promise exciting prospects for the future. © 2014 American Heart Association, Inc. Source

Lin C.-Y.,National Chiao Tung University | Jones B.A.,IBM
Physical Review B - Condensed Matter and Materials Physics | Year: 2011

The engineered spin structures recently built and measured in scanning tunneling microscope experiments are calculated using density functional theory. By determining the precise local structure around the surface impurities, we find that the Mn atoms can form molecular structures with the binding surface, behaving like surface molecular magnets. The spin structures are confirmed to be antiferromagnetic, and the exchange couplings are calculated within 8% of the experimental values simply by collinear-spin generalized gradient approximation +U calculations. We can also explain why the exchange couplings significantly change with different impurity binding sites from the determined local structure. The bond polarity is studied by calculating the atomic charges with and without the Mn adatoms. In addition, we study a second adatom, Co. We study the surface Kondo effect of Co by calculating the surrounding local density of states and the on-site Coulomb Uand compare and contrast the behavior of Co and Mn. Finally, our calculations confirm that the Mn and Co spins of these structures are 5/2 and 3/2, respectively, as also measured indirectly by scanning tunneling microscope. © 2011 American Physical Society. Source

Peng W.,Michigan State University | Crouse J.C.,Michigan State University | Lin J.-H.,National Chiao Tung University
Health Education and Behavior | Year: 2013

This systematic review evaluates interventions using active video games (AVGs) to increase physical activity and summarizes laboratory studies quantifying intensity of AVG play among children and adults. Databases (Cochrane Library, PsychInfo, PubMed, SPORTDiscus, Web of Science) and forward citation and reference list searches were used to identify peer-reviewed journal articles in English through March 2011. Studies that used off-the-shelf AVGs to increase physical activity with quantitative outcomes or studies that quantified intensity of AVG play were included. Information on sample characteristics, AVGs employed, study design and conditions, outcome measures, results, and conclusions was extracted by two researchers. Intervention studies were ranked on design quality. Thirteen interventions and 28 laboratory studies were identified. All laboratory studies demonstrated that AVGs are capable of providing light-to-moderate intensity physical activity. However, only three interventions supported AVGs as an effective tool to significantly increase physical activity or exercise attendance. As AVGs are becoming more popular, additional research is needed to determine how to capitalize on the potential of AVGs to increase physical activity. © 2012 Society for Public Health Education. Source

Su C.-T.,National Tsing Hua University | Yeh C.-J.,National Chiao Tung University
Microelectronics Reliability | Year: 2011

The yield of IC assembly manufacturing is dependent on wire bonding. Recently, the semiconductor industry demands smaller IC designs and higher performance requirements. As such, bonding wires must be stronger, finer, and more solid. The cost of gold is continuously appreciating, and this has become a key issue in IC assembly and design. Copper wire bonding is an alternative solution to this problem. It is expected to be superior over Au wires in terms of cost, quality, and fine-pitch bonding pad design. To obtain the best wire bonding quality, we employed Taguchi methods in optimizing the Cu wire bonding process. With Cu wire bonding technology, the production yield increased from 98.5% to 99.3% and brought approximately USD 0.7 million in savings. © 2010 Elsevier Ltd. All rights reserved. Source

Pao H.-T.,National Chiao Tung University | Fu H.-C.,Huaqiao University
Renewable and Sustainable Energy Reviews | Year: 2013

This study employs Brazil's yearly statistics from 1980 to 2010 to explore the causal relationships between the real GDP and four types of energy consumption: non-hydroelectric renewable energy consumption (NHREC), total renewable energy consumption (TREC), non-renewable energy consumption (NREC), and the total primary energy consumption (TEC). The cointegration test reveals a long-run equilibrium among Brazil's real GDP, labour, capital, and each of the four types of consumption. The development of the Brazilian economy has close ties with capital formation and labour force. The influence of NHREC/TREC on real output is positive and significant, while the impacts by NREC/TEC are insignificant. The results from the vector error correction models reveal a unidirectional causality from NHREC to economic growth, a bidirectional causality between economic growth and TREC, and a unidirectional causality from economic growth to NREC or TEC without feedback in the long-run. These findings suggest that Brazil is an energy-independent economy and that economic growth is crucial in providing the necessary resources for sustainable development. Expanding renewable energy would not only enhance Brazil's economic growth and curb the deterioration of the environment but also create an opportunity for a leadership role in the international system and improve Brazil's competition with more developed countries. © 2013 Elsevier Ltd. Source

Rosenstein B.,National Chiao Tung University | Rosenstein B.,Ariel University | Lewkowicz M.,Ariel University
Physical Review B - Condensed Matter and Materials Physics | Year: 2013

The response to an electric field (dc and ac) of electronic systems in which the Fermi "surface" consists of a number of three-dimensional (3D) Weyl points (such as some pyrochlore iridates) exhibits a peculiar combination of characteristics usually associated with insulating and conducting behavior. Generically a neutral plasma in clean materials can be described by a tight-binding model with a strong spin-orbit interaction. A system of that type has a vanishing dc conductivity; however the current response to the dc field is very slow: The current decays with time in a powerwise manner, different from an insulator. The ac conductivity, in addition to a finite real part σ′(Ω) which is linear in frequency, exhibits an imaginary part σ′′(Ω) that increases logarithmically as a function of the UV cutoff (atomic scale). This leads to a substantial dielectric response like a large dielectric constant at low frequencies. This is in contrast to a two-dimensional (2D) Weyl semimetal-like graphene at a neutrality point where the ac conductivity is purely pseudodissipative. The Coulomb interaction between electrons is long range and sufficiently strong to make a significant impact on transport. The interaction contribution to the ac conductivity is calculated within the tight-binding model. The result for the real part expressed via the renormalized (at frequency Ω̄) Fermi velocity v is Δσ ′(Ω)=e4Ω/(9π2âv)[2log(Ω/ Ω̄)-5]. © 2013 American Physical Society. Source

Chao I.-F.,Yuan Ze University | Yuang M.C.,National Chiao Tung University
Journal of Lightwave Technology | Year: 2013

Optical WDM metro-ring networks have been considered to be promising solutions for wireless backhaul. In this paper, we propose an integrated traffic control scheme (ITCS), which facilitates circuit emulation service (CES) for wireless backhaul over a previously proposed experimental optical packet-switched WDM metro-ring network, HOPSMAN. The ITCS seamlessly integrates variable-bit-rate (VBR) CES wireless with connection-less best-effort data, satisfying stringent QoS requirements and retaining maximal network throughput. The ITCS ensures efficient setup of CES connections by employing a simple mean-rate-based distributed admission control followed by a novel slot-marking reservation. The total connection setup delay is comprised of the setup queueing delay and slot-marking delay. While the slot-marking delay is nearly a ring time, the mean setup queueing delay is formally computed through an accurate approximation based on an M/G/m queueing analysis. We show simulation results to demonstrate that the ITCS accommodates remarkably high CES traffic loads while satisfying a wide range of delay requirements for wireless backhaul. Taking the background best-effort traffic into account, ITCS achieves exceedingly low delay, jitter, and delay bound for CES under various traffic loads and burstiness. © 1983-2012 IEEE. Source

Gau R.-H.,National Chiao Tung University
IEEE Transactions on Wireless Communications | Year: 2011

In this paper, we propose the tree/stack splitting with remainder algorithm for distributed medium access control in a wireless network with multipacket reception. In order to reduce the length of a cycle and increase the network throughput, when the splitting with remainder algorithm is used, some nodes that attempt to transmit packets at the beginning of a cycle might have to postpone their packet retransmissions until the beginning of the next cycle. We demonstrate that the splitting with remainder algorithm outperforms the erasure algorithm and the probe algorithm. For the splitting with remainder algorithm, we analytically and accurately derive the network throughput and the average packet delay. We show that our analytical results are consistent with packet-based simulation results. © 2006 IEEE. Source

Chiu Y.Y.,National Chiao Tung University
BMC genomics | Year: 2012

To discover a compound inhibiting multiple proteins (i.e. polypharmacological targets) is a new paradigm for the complex diseases (e.g. cancers and diabetes). In general, the polypharmacological proteins often share similar local binding environments and motifs. As the exponential growth of the number of protein structures, to find the similar structural binding motifs (pharma-motifs) is an emergency task for drug discovery (e.g. side effects and new uses for old drugs) and protein functions. We have developed a Space-Related Pharmamotifs (called SRPmotif) method to recognize the binding motifs by searching against protein structure database. SRPmotif is able to recognize conserved binding environments containing spatially discontinuous pharma-motifs which are often short conserved peptides with specific physico-chemical properties for protein functions. Among 356 pharma-motifs, 56.5% interacting residues are highly conserved. Experimental results indicate that 81.1% and 92.7% polypharmacological targets of each protein-ligand complex are annotated with same biological process (BP) and molecular function (MF) terms, respectively, based on Gene Ontology (GO). Our experimental results show that the identified pharma-motifs often consist of key residues in functional (active) sites and play the key roles for protein functions. The SRPmotif is available at http://gemdock.life.nctu.edu.tw/SRP/. SRPmotif is able to identify similar pharma-interfaces and pharma-motifs sharing similar binding environments for polypharmacological targets by rapidly searching against the protein structure database. Pharma-motifs describe the conservations of binding environments for drug discovery and protein functions. Additionally, these pharma-motifs provide the clues for discovering new sequence-based motifs to predict protein functions from protein sequence databases. We believe that SRPmotif is useful for elucidating protein functions and drug discovery. Source

Hsiao Y.-C.,National Taiwan University | Lee W.,National Chiao Tung University
Optics Express | Year: 2013

Dual-frequency cholesteric liquid crystal (DFCLC) devices characteristically require high operation voltage, which hinders their further development in thin-film-transistor driving. Here we report on a lowervoltage switching method based on the thermodielectric effect. This technique entails applying a high-frequency voltage to occasion dielectric oscillation heating so to induce the increase in crossover frequency. The subsequent change in dielectric anisotropy of the DFCLC allows the switching, with a lower operation voltage, from the planar state to the focal conic or homeotropic state. The temperature rise incurred by the dielectric heating is described. © 2013 Optical Society of America. Source

Kuo H.-Y.,National Chiao Tung University | Bhattacharya K.,California Institute of Technology
Mechanics of Materials | Year: 2013

We propose a theoretical framework for evaluation of magnetoelectroelastic potentials in a fibrous composite with piezoelectric and piezomagnetic phases, motivated by the technological desire for materials with large magnetoelectric coupling. We show that the problem with transversely isotropic phases can be decomposed into two independent problems, plane strain with transverse electromagnetic fields and anti-plane shear with in-plane electromagnetic fields. We then consider the second problem in detail, and generalize the classic work of Lord Rayleigh (1892) to obtain the electrostatic potential in an ordered conductive composite and its extension to a disordered system by Kuo and Chen (2008) to the current coupled magnetoelectroelastic problem. We use this method to study BaTiO3-CoFe2O4 composites and provide insights into obtaining large effective magnetoelectric coefficient. © 2012 Elsevier Ltd. All rights reserved. Source

This study compared clicker technology against mobile polling and the Just-in-Time Teaching (JiTT) strategy to investigate how these methods may differently affect students' anxiety, self-efficacy, engagement, academic performance, and attention and relaxation as indicated by brainwave activity. The study utilized a quasi-experimental research design. To assess the differences between the effects of clickers and mobile polling, the study collected data from two courses at a large research university in Taiwan in which 69 students used either clickers or mobile polling. The results showed that mobile polling along with the JiTT strategy and in-class polls reduce graduate students' anxiety, improve student outcomes in an environment comprising both graduate and undergraduate students, and increase students' attention during polling. However, brainwave data revealed that during the polling activities, students' attention in the clicker and mobile polling groups respectively increased and decreased. Students nowadays do not find smartphones a novelty; however, incorporating them into class is still a potentially effective way to increase student attention and provide a direct way for instructors to observe the learning effects of lectures and improve their teaching approach on that basis. © 2013 Elsevier Ltd. All rights reserved. Source

Wu J.-Y.,National Chiao Tung University
Journal of Computer Assisted Learning | Year: 2014

This study examined how knowledge of metacognitive strategies and navigation skills mediate the relationship between online reading activities and printed reading assessment (PRA) and electronic reading assessment (ERA) across 19 countries using the PISA (Programme for International Student Assessment) 2009 database. Participants were 34104 fifteen-year-old students (female: 50.1%). The results showed that information-seeking activity, knowledge of metacognitive strategies and navigations skills positively predicted ERA and PRA. Social reading activities negatively predicted knowledge of metacognitive strategies and PRA but had no effect on ERA and the navigation skills in most countries. Increased information-seeking reading resulted in higher ERA and PRA as demonstrated by navigation skills and knowledge of metacognitive strategies. Gender differences in online reading engagement were not statistically significant in most countries. However, girls performed better in knowledge of metacognitive strategies, navigation skills and PRA but were not significantly better on ERA. Multiple group comparisons of gender indicated that the hypothesized model held for both boys and girls. Besides the infrastructure of information and communications technology as a tool to access the cyber informational space, students should be empowered to use appropriate strategies and navigation skills to achieve their goals. Implications for teaching and learning practices are discussed. © 2014 John Wiley & Sons Ltd. Source

Wang C.-H.,National Chiao Tung University
Computers and Industrial Engineering | Year: 2016

Smartphone has been recognized as one of the most powerful mobile carriers because of its portability, multiple functions, and wireless connectivity. However, the market shares of mobile phones have been intensively fluctuating because many brand companies like Nokia or Motorola have been merged. In order to brainstorm innovative ideas, this paper incorporates the theory of inventive problem solving (TRIZ) into quality function deployment (QFD) to address the following issues: (1) a smartphone is characterized by marketing requirements (MRs) and technical attributes (TAs), (2) engineering conflicts among TAs are tackled by TRIZ, (3) user preferences for MRs are extracted to form a basis of market segmentation, (4) user perceptions of TAs are captured to identify significant features with regard to the . ad-hoc segments. More importantly, numerous industrial examples including Sony's QX series, Samsung's . K-zoom, Nokia's Lumia 1020, Asus's Zenfone zoom, Asus's Padfone series, LG's . G flex, Samsung's galaxy beam, and Lenovo's Yoga Tablet 2 are illustrated to validate this research. In brief, this study does not only provide a way to handle engineering conflicts in designing smartphones but also help product planners generate innovative alternatives for acquiring the . ad-hoc niche segments. © 2016 Elsevier Ltd. Source

Yang C.-H.,National Chiao Tung University | Yu T.-H.,University of California at Los Angeles | Markoviae D.,University of California at Los Angeles
IEEE Journal of Solid-State Circuits | Year: 2012

This paper presents a design methodology for power and area minimization of flexible FFT processors. The methodology is based on the power-area tradeoff space obtained by adjusting algorithm, architecture, and circuit variables. Radix factorization is the main technique for achieving high energy efficiency with flexibility, followed by architecture parallelism and delay line circuits. The flexibility is provided by reconfigurable processing units that support radix-2/4/8/16 factorizations. As a proof of concept, a 128- to 2048-point FFT processor for 3GPP-LTE standard has been implemented in a 65-nm CMOS process. The processor designed forminimum power-area product is integrated in 1.25 × 1.1 mm 2 and dissipates 4.05 mW at 0.45 V for the 20 MHz LTE bandwidth. The energy dissipation ranging from 2.5 to 103.7 nJ/FFT for 128 to 2048 points makes it the lowest energy flexible FFT. © 2012 IEEE. Source

Tsai W.-J.,National Chiao Tung University | You H.-Y.,Quanta Computer Inc.
IEEE Transactions on Circuits and Systems for Video Technology | Year: 2012

Multiple description video coding (MDC) is one of the approaches for reducing the detrimental effects caused by transmission over error-prone networks. In this paper, a MDC model based on hierarchical B pictures is proposed to optimize the tradeoff between coding efficiency and error resilience. The model produces two descriptors by applying different MDC techniques such as duplication, spatial splitting and temporal splitting on the different frames of video sequences, taking into account unequal importance of frames at different hierarchical levels. Duplication (high redundancy) is for key frames: spatial splitting (medium redundancy) for reference B frames, and temporal splitting (low redundancy) for nonreference B frames. For one descriptor loss, the model applies different estimation methods, but for the two descriptor loss case, the same temporal estimation is employed. As a consequence, better error resilience can be achieved at high coding efficiency. The advantages of the proposed model are demonstrated in error-free and packet loss networks. © 2011 IEEE. Source

Hashimoto S.,Tokushima University | Werner D.,Tokushima University | Uwada T.,National Chiao Tung University
Journal of Photochemistry and Photobiology C: Photochemistry Reviews | Year: 2012

This review describes the fundamental aspects of laser-gold nanoparticle (Au NP) interaction that leads to nanoscale energy deposition to the surroundings through light amplification and heat generation. Besides the importance of the primary process in physics and chemistry, application of the light-NP interaction has attracted significant interest from various areas ranging from analytical chemistry to material chemistry and biomedicine. Here we consider both mechanistic and application aspects. Our attention is focused on pulsed-laser-induced fast processes that revealed the heating-cooling dynamics of electrons, lattice (particle), and particle's environment. On the application side, we focus on material fabrication and processing that beat diffraction-limited resolution. Together, we will shed a light on the essence of research activities carried out in the past 10 years. In addition to an abundance of latest information obtained from currently available literature, this review includes figures obtained by our own calculations to provide readers with a better understanding of the basics of the optical properties and energy and heat-transfer processes of Au NPs, which are not familiar to photochemists. © 2012 Elsevier B.V. Source

Chen K.-Y.,Industrial Technology Research Institute of Taiwan | Hu J.-S.,National Chiao Tung University
IEEE Transactions on Power Electronics | Year: 2012

A filtered space-vector pulse-width modulation (SVPWM) considering finite pulse-width resolution is proposed to produce a switching sequence with reduced baseband harmonics for multiphase voltage source inverters (VSI). The conventional SVPWM is sensitive to the pulse-width resolution which leads to increased harmonic distortion in digital-based implementations. By incorporating a pseudofeedback loop regarding weighted voltage difference between desired and produced phase voltages, the quantization error induced by finite pulse-width resolution is compensated, yielding a better tracking performance. The gating signals for multiphase VSIs are presented through rigorous mathematical derivation. In simulations and experiments, harmonic distortions of SVPWMs with and without filter compensation under various pulse-width resolutions are shown. The results confirm the effectiveness of the proposed scheme. The main advantage realized is reduction of acoustic noise and increased tracking accuracy. © 2012 IEEE. Source

Wang T.,National Chiao Tung University
IEEE Transactions on Systems, Man, and Cybernetics, Part B: Cybernetics | Year: 2011

Cluster ensembles have attracted a lot of research interests in recent years, and their applications continue to expand. Among the various algorithms for cluster ensembles, those based on coassociation matrices are probably the ones studied and used the most because coassociation matrices are easy to understand and implement. However, the main limitation of coassociation matrices as the data structure for combining multiple clusterings is the complexity that is at least quadratic to the number of patterns N. In this paper, we propose CA-tree, which is a dendogram-like hierarchical data structure, to facilitate efficient and scalable cluster ensembles for coassociation-matrix-based algorithms. All the properties of the CA-tree are derived from base cluster labels and do not require the access to the original data features. We then apply a threshold to the CA-tree to obtain a set of nodes, which are then used in place of the original patterns for ensemble-clustering algorithms. The experiments demonstrate that the complexity for coassociation-based cluster ensembles can be reduced to close to linear to N with minimal loss on clustering accuracy. © 2010 IEEE. Source

Shih P.T.-Y.,National Chiao Tung University
Journal of Surveying Engineering | Year: 2014

The digital elevation products produced by the Shuttle Radar Topography Mission (SRTM) are disseminated with different resolutions. This study investigates the differences in information content between different resolutions. Three 1° cells are selected to represent flat area, moderate terrain, and mountain ranges. All of these cells are located in the continental territory of the United States. The theory of information loss caused by the sampling density is shown with the increasing deviation from the reference in the experiment. The error resulting from bilinear interpolation is also assessed. The experimental result also indicates that if the 1-arcsecond SRTM, digital elevation model (DEM) is released for global coverage, the height accuracy would be improved ~10% over the 3-arcsecond product. © 2014 American Society of Civil Engineers. Source

Cheng T.C.E.,Hong Kong Polytechnic University | Chung Y.-H.,National Chiao Tung University | Liao S.-C.,Feng Chia University | Lee W.-C.,Feng Chia University
Computers and Operations Research | Year: 2013

In many management situations multiple agents pursuing different objectives compete on the usage of common processing resources. In this paper we study a two-agent single-machine scheduling problem with release times where the objective is to minimize the total weighted completion time of the jobs of one agent with the constraint that the maximum lateness of the jobs of the other agent does not exceed a given limit. We propose a branch-and-bound algorithm to solve the problem, and a primary and a secondary simulated annealing algorithm to find near-optimal solutions. We conduct computational experiments to test the effectiveness of the algorithms. The computational results show that the branch-and-bound algorithm can solve most of the problem instances with up to 24 jobs in a reasonable amount of time and the primary simulated annealing algorithm performs well with an average percentage error of less than 0.5% for all the tested cases. © 2012 Elsevier Ltd. All rights reserved. Source

Wang H.,National Chiao Tung University
Molecular Phylogenetics and Evolution | Year: 2011

In the nucleotide substitution model for molecular evolution, a major task in the exploration of an evolutionary process is to estimate the substitution number per site of a protein or DNA sequence. The usual estimators are based on the observation of the difference proportion of the two nucleotide sequences. However, a more objective approach is to report a confidence interval with precision rather than only providing point estimators. The conventional confidence intervals used in the literature for the substitution number are constructed by the normal approximation. The performance and construction of confidence intervals for evolutionary models have not been much investigated in the literature. In this article, the performance of these conventional confidence intervals for one-parameter and two-parameter models are explored. Results show that the coverage probabilities of these intervals are unsatisfactory when the true substitution number is small. Since the substitution number may be small in many situations for an evolutionary process, the conventional confidence interval cannot provide accurate information for these cases. Improved confidence intervals for the one-parameter model with desirable coverage probability are proposed in this article. A numerical calculation shows the substantial improvement of the new confidence intervals over the conventional confidence intervals. © 2011 Elsevier Inc. Source

Alemu D.,Academia Sinica, Taiwan | Alemu D.,National Tsing Hua University | Wei H.-Y.,National Taiwan University | Ho K.-C.,National Taiwan University | And 2 more authors.
Energy and Environmental Science | Year: 2012

We proposed a simple yet robust film treatment method with methanol having only one hydroxyl group to enhance the conductivity of poly(3,4- ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) by four orders of magnitude. Different methods of film treatment: immersing PEDOT:PSS film in the methanol solution; dropping methanol on the film; and a combination of these are employed and the results are compared. The conductivity of PEDOT:PSS films was enhanced from 0.3 S cm -1 to 1362 S cm -1 after film treatment with methanol. Other alcohols like ethanol and propanol were also used to treat the PEDOT:PSS film and showed inferior conductivity enhancement compared to methanol. The conductivity enhancement was greatly affected by the hydrophilicity and dielectric constant of the alcohols used. The mechanism of conductivity enhancement was investigated through various characterization techniques including FTIR, XPS and AFM. Removal of the insulator PSS from the film, and morphology and conformational changes are the mechanisms for the conductivity enhancement. The treated films also showed high transmittance and low sheet resistance desirable for a standalone electrode. ITO-free polymer solar cells were fabricated using PEDOT:PSS electrodes treated with methanol and showed almost equal performance to ITO electrodes. © 2012 The Royal Society of Chemistry. Source

The asymptotic corrugations boundary condition (ACBC) is used together with classical theory of vector potentials to analyze planar corrugations. A transcendental characteristic equation is derived, from which the dispersion diagram can be obtained, thereby conveying surface wave passband and stopband properties, even for propagation within oblique azimuth planes as well as both principal TE and TM polarizations. From the formulation, field distributions for the regions within the grooves and above the corrugations can also be generated. When compared with the dispersion graphs obtained from characteristic equations derived by the classical transverse resonance technique (TRT), the newly presented ACBC method provides superior accuracy. Explicit formulas for the complex reflection coefficient (amplitude and phase) for both TE and TM polarized plane-wave incidences are also derived as closed-form analytic functions of all parameters (especially the azimuth phi angle of incidence) using a novel concept of unusual transversely phased plane-waves. These proposed approaches are massively more efficient than full-wave solvers, providing unparalleled speedup of computation by thousands of times. The surface-wave and reflection properties of planar corrugations are thus herein analyzed in a unified, complete, and elegant manner that is also highly efficient but yet accurate. This thorough work is thus a great boost to the continued use of corrugated surfaces as artificial magnetic conductors (AMC), electromagnetic bandgap (EBG) structures, and soft/hard surfaces in all walks of antenna design, especially in terms of speed and accuracy. © 1963-2012 IEEE. Source

Pao H.-T.,National Chiao Tung University | Fu H.-C.,Hua Qiao University
Energy | Year: 2015

In view of limited natural resources on Earth, linkage among environment, energy, and economy (3Es) becomes important perspectives for sustainable development. This paper proposes to use Lotka-Volterra model for SUstainable Development (LV-SUD) to analyse the interspecific interactions, equilibria and their stabilities among emissions, different types of energy consumption (renewable, nuclear, and fossil fuel), and real GDP, the main factors of 3Es issues. Modelling these interactions provides a useful multivariate framework for prediction outcomes. Interaction between 3Es, namely competition, symbiosis, or predation, plays an important role in policy development to achieve a balanced use of energy resources and to strengthen the green economy. Applying LV-SUD in Mexico, an emerging markets country, analysing results show that there is a mutualism between fossil fuel consumption and GDP; prey-predator relationships that fossil fuel and GDP enhance the growth of emissions, but emissions inhibit the growth of the others; and commensalisms that GDP benefits from nuclear power, and renewable power benefits from fossil fuel. It is suggested that national energy policies should remain committed to decoupling the relevance between non-clean energy and GDP, to actively developing clean energy and thereby to properly reducing fossil fuel consumption and emissions without harming economic growth. © 2015 Elsevier Ltd. Source

Chow C.W.,National Chiao Tung University | Yeh C.H.,Industrial Technology Research Institute of Taiwan
IEEE Photonics Journal | Year: 2013

A migration scheme from time-division-multiplex passive optical network (TDM-PON) to wavelength-division-multiplex PON (WDM-PON) using differential phase-shift keying (DPSK) for the downstream signal and wavelength-shifted amplitude-shift keying (WS-ASK) for the upstream signal is demonstrated. The migration scheme does not change the existing fiber infrastructure. An optical filter is preinstalled at the optical networking unit (ONU) to select the desirable downstream wavelength for the WDM-PON and simultaneously demodulate the downstream DPSK signal. Signal remodulation is used to generate the upstream signal by reusing the downstream wavelength. In the ONU, by wavelength shifting the upstream optical spectrum with respect to the downstream optical spectrum, the Rayleigh backscattering (RB) interference beat noise affecting the upstream signal can be significantly mitigated. The optimum bandwidth for the downstream DPSK demodulation is analyzed. The downstream and upstream transmission performances at different split ratios are also discussed. © 2012 IEEE. Source

Yeh C.H.,Industrial Technology Research Institute of Taiwan | Chow C.W.,National Chiao Tung University | Chen H.Y.,Industrial Technology Research Institute of Taiwan
Journal of Lightwave Technology | Year: 2012

We propose and experimentally demonstrate a new colorless wavelength-division-multiplexed passive optical network (WDM-PON) architecture with the Rayleigh backscattering (RB) interferometric beat noise mitigation by using cross-remodulation architecture. The proposed WDM-PON has a simply configuration by combining two WDM-PONs at two wavelength bands to support twice the number of users. We experiment different m-quadrature amplitude modulation (QAM) (m = 16, 32 and 64) orthogonal frequency division multiplexing (OFDM) downstream signal and the remodulated on-off keying (OOK) upstream signal by using the 2.5 GHz directly modulated laser (DML) and 1.2 GHz reflective semiconductor optical amplifier (RSOA) respectively. Hence, the total data rate achieved for the downstream signals are 10 Gb/s, 12.5 Gb/s, and 15 Gb/s respectively for different m -QAM. For the upstream signal, we over-drive the RSOA and 2.5 Gb/s OOK upstream traffic can be achieved. In addition, the proposed PON can also be upgraded to support more wavelength bands to meet the increase demand of capacity. © 1983-2012 IEEE. Source

Wen W.-Y.,Chung Yuan Christian University | Wen W.-Y.,National Taiwan University | Wu S.-Y.,National Chiao Tung University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2012

In this Letter, we study the dipole coupling effect of holographic fermion in a charged dilatonic black hole proposed by Gubser and Rocha (2010) [1]. It is found that the property of Fermi liquid is rigid under perturbation of dipole coupling, and the Fermi momentum is linearly shifted. A gap is dynamically generated as the coupling becomes large enough and the Fermi surface ceases to exist as the bulk dipole coupling further increases. © 2012 Elsevier B.V. Source

Lee M.-T.,National Chiao Tung University
Journal of the Physical Society of Japan | Year: 2012

In this research, we develop a many-body Green's function approach for interacting composite bosons in the Bose-Einstein condensed phase. The resummation scheme dealing with the carrier-carrier exchange between many-body composite bosons in cold condensation is manifested as a diagrammatic technique through the introduction of a set of Dyson equations for composite bosons. We diagrammatically calculate the specific heat capacity of neutral composite bosons, made of mass-imbalanced fermions with opposite charges, up to the first orders of the Pauli exchange and Coulomb interaction. Condensate phenomena due to the effect of the carrier-carrier exchange are discussed. In comparison with the approximation that composite bosons behave like interacting fundamental bosons, our result shows that the energy reduction from the carrier-carrier exchange stabilizes composite-boson condensates. © 2012 The Physical Society of Japan. Source

Yeh C.-H.,Industrial Technology Research Institute of Taiwan | Yeh C.-H.,Fu Jen Catholic University | Liu Y.-L.,Industrial Technology Research Institute of Taiwan | Chow C.-W.,Industrial Technology Research Institute of Taiwan | Chow C.-W.,National Chiao Tung University
Optics Express | Year: 2013

In this demonstration, we first demonstrate a real-time phosphor-LED visible light communication (VLC) system with 37 Mbit/s total throughput under a 1.5 m free space transmission length. The transmitter and receiver modules are compact size. Utilizing our proposed preequalization technology, the ~1 MHz bandwidth of phosphor LED could be extended to ~12 MHz without using blue filter. Thus, the increase in bandwidth would enhance the traffic data rate for VLC transmission. The maximum bit-rate achieved by the VLC system is 37 Mbit/s, and a video transmission at 28.419 Mbit/s is demonstrated using the proposed VLC system. In addition, the relationships of received power and signal performance are discussed and analyzed. ©2013 Optical Society of America. Source

Hung S.-K.,National Chiao Tung University
Journal of Nanoscience and Nanotechnology | Year: 2010

A spiral scanning method is proposed for atomic force microscopy with thoroughgoing analysis and implementation. Comparing with the traditional line-by-line scanning method, the spiral scanning method demonstrates higher imaging speed, minor image distortion, and lower acceleration, which can damage the piezoelectric scanner. Employing the spiral scanning method to replace the lineby-line scanning method, the experiment shows that the time to complete an imaging cycle can be reduced from 800 s to 314 s without sacrificing the image resolution. © 2010 American Scientific Publishers. Source

Wu J.-Y.,National Chiao Tung University
Computers and Education | Year: 2015

The Internet has become a major platform for learning in higher education. Besides rich informational resources, however, the Internet offers an abundance of distractors that challenge students' attention. This study investigated university students' perceived attention state and use of regulatory strategies using the Online Learning Motivated Attention and Regulatory Strategies scale (OL-MARS). Participants were 230 undergraduate and graduate students recruited from two universities located in central and northern Taiwan. The exploratory factor analysis revealed four subscales in the OL-MARS, including perceived attention discontinuity, social media notification, behavioral strategies, and mental strategies. Results showed that mental and behavioral strategies were positively associated with criterion variables, including Internet self-efficacy, online search strategies, and final course grades, but negatively correlated with time spent on the Internet and social media. Whereas, perceived attention discontinuity and social media notification mostly had a modest correlational relationship with these validating variables in an opposite direction. Cluster analysis identified five types of profiles: the Motivated Strategic, the Unaware, the Hanging On, the Non-Responsive and the Self-Disciplined. Group membership exhibited mean differences in Internet self-efficacy, online search strategies, final course grades, and time spent on the Internet and social media. The study results validated the constructs in meta-attention for theory development, provided the OL-MARS scale as an effective meta-attention measurement tool to assess university students' knowledge of attention and regulation of attention, and proposed the specific intervention and attention regulation training for each profile group. © 2015 Elsevier Ltd. All rights reserved. Source

Wang C.-W.,MStar Semiconductor Inc. | Wang L.-C.,National Chiao Tung University
IEEE Journal on Selected Areas in Communications | Year: 2012

In this paper, we present an analytical framework to evaluate the effects of multiple spectrum handoffs on channel utilization and latency performances in cognitive radio (CR) networks. During the transmission period of a secondary connection, multiple interruptions from the primary users result in multiple spectrum handoffs. In order to decide the target channel for each spectrum handoff and resume the unfinished transmission, wideband sensing is performed in an on-demand reactive manner. Although spectrum handoff procedure can enhance channel utilization, transmission latency of the secondary users is prolonged due to multiple handoffs. Thus, two fundamental issues in CR networks with multiple spectrum handoffs arise: (1) to what extent the channel utilization can be improved; and (2) how long the transmission latency will be extended for the secondary users. To solve the first problem, we introduce the preemptive resume priority (PRP) M/G/1 queueing network to characterize the channel usage behaviors of CR networks. Based on this queueing network, channel utilization under various traffic arrival rates and service time distributions can be evaluated. Furthermore, on top of the proposed queueing network, a state diagram is developed to characterize the effects of multiple handoff delay on the transmission latency of the secondary users. The analytical results can provide a helpful insight to study the effects of traffic arrival rates and service time on channel utilization and transmission latency and then facilitate the designs of admission control rules for the secondary users subject to their performance requirements. © 2012 IEEE. Source

Gau R.-H.,National Chiao Tung University
IEEE Communications Letters | Year: 2012

In this letter, we analyze the physical layer secrecy throughput in wireless fading networks with independent eavesdroppers that do not collude. We study the impacts of the total number of eavesdroppers on the secrecy throughput. In addition, we propose two channel-adaptive transmission policies for improving the secrecy throughput. The proposed transmission policies have low computational complexity and therefore are feasible in practice. We use analytical results and simulation results to justify the usage of the proposed schemes. © 1997-2012 IEEE. Source

Wang S.-Y.,National Chiao Tung University | Chou C.-L.,EstiNet Technologies Inc | Yang C.-M.,EstiNet Technologies Inc
IEEE Communications Magazine | Year: 2013

In this article, we introduce the EstiNet OpenFlow network simulator and emulator, and present its support for testing the functions and evaluating the performances of software-defined networks¿ OpenFlow controller¿s application programs. EstiNet uses an unique kernel reentering simulation methodology to enable unmodified real applications to run on nodes in its simulated network. As a result, without any modification, real NOX/POX or Floodlight OpenFlow controllers can readily run on a host in an EstiNet simulated network to control thousands of simulated OpenFlow switches. EstiNet has the characteristics of a simulator and an emulator at the same time. It combines the advantages of the simulation and emulation approaches without their respective shortcomings. EstiNet uses real OpenFlow controller programs, real network application programs, and the real TCP/IP protocol stack in the Linux kernel to generate correct, accurate, and repeatable SDN application performance results. In this article, we compare EstiNet with ns-3 and Mininet regarding their capabilities, performance, and scalability. © 1979-2012 IEEE. Source

Chang S.-W.,Academia Sinica, Taiwan | Chang S.-W.,National Chiao Tung University
Journal of Lightwave Technology | Year: 2014

We show that the bidirectionality of optical modes exists in general bianisotropic but reciprocal photonic crystals and related structures. Using this property, we obtain an alternative bidirectionality of modes with sources (gain) in active photonic crystals. In the former, we conclude that degeneracies of modes with complex anti-parallel wave vectors are always identical as long as the structure is reciprocal. With the latter, we setup an associated biorthogonality relation in the Rayleigh-Carson form for modes in active photonic crystals. © 1983-2012 IEEE. Source

This study investigated whether media interactivity would influence the short-term effects of violent content on audience aggression. The general aggression model, social cognitive theory, and character identification offered the theoretical framework. A random sample of 102 male college students were randomly assigned to one of three conditions: video game playing, recorded game-play watching, or movie watching. The results indicated that video game players (mediated enactive experience) experienced greater increases in aggressive affect, aggressive cognition, and physiological arousal than participants who watched recorded game play or comparable movie scenes (mediated observational experience). The study indicated that media interactivity in video game exacerbated the violent effect on short-term, aggressive responses. Character identification did not mediate the effect of media interactivity on aggression. Future studies should incorporate more comprehensive measures of character identification to investigate inconsistent findings regarding media interactivity and identification. © 2012 Elsevier Ltd. All rights reserved. Source

Rosenstein B.,National Chiao Tung University | Li D.,Peking University
Reviews of Modern Physics | Year: 2010

Thermodynamics of type II superconductors in electromagnetic field based on the Ginzburg-Landau theory is presented. The Abrikosov flux lattice solution is derived using an expansion in a parameter characterizing the "distance" to the superconductor-normal phase transition line. The expansion allows a systematic improvement of the solution. The phase diagram of the vortex matter in magnetic field is determined in detail. In the presence of significant thermal fluctuations on the mesoscopic scale (for example, in high Tc materials) the vortex crystal melts into a vortex liquid. A quantitative theory of thermal fluctuations using the lowest Landau level approximation is given. It allows one to determine the melting line and discontinuities at melt, as well as important characteristics of the vortex liquid state. In the presence of quenched disorder (pinning) the vortex matter acquires certain "glassy" properties. The irreversibility line and static properties of the vortex glass state are studied using the "replica" method. Most of the analytical methods are introduced and presented in some detail. Various quantitative and qualitative features are compared to experiments in type II superconductors, although the use of a rather universal Ginzburg-Landau theory is not restricted to superconductivity and can be applied with certain adjustments to other physical systems, for example, rotating Bose-Einstein condensate. © 2010 The American Physical Society. Source

Hsu C.-I.,National Chiao Tung University | Li H.-C.,Ta Hwa University of Science and Technology
International Journal of Production Economics | Year: 2011

This study focuses on supply chain network design problems by considering economies of scale and demand fluctuations. A reliability evaluation method is developed to evaluate the performance of plants under demand fluctuations. In addition, two mathematical programming models are developed to determine the optimal adjustment decisions regarding production reallocation among plants under different fluctuating demands. The judgments to adjust or to do-nothing are investigated by comparing the results if the adjustment is made or not made. Results show that making adjustments benefits the manufacturers by reducing total production cost and avoiding revenue loss, which outweighs the extra costs, especially for high value-added products. Results also suggest that the manufacturer should ignore a short period abnormal state, since the benefits to respond to it might not compensate the high allocation costs. The results of this study provide a reference for the manufacturer in their decision making process of network planning with demand fluctuations, when they have to cope with benefits and costs during abnormal states. © 2011 Elsevier B.V. All rights reserved. Source

Hsu C.-J.,National Chiao Tung University | Sheen W.-H.,Chaoyang University of Technology
IEEE Transactions on Wireless Communications | Year: 2012

Direct-conversion radio architecture is a low-cost, low-power and small-size design that has been widely employed in today's wireless devices. This architecture, however, induces radio impairments such as I-Q imbalance and dc offset that may incur severe degradation in communication performance if left uncompensated. In this paper, a new method is proposed to calibrate simultaneously a transceiver's own transmitter and receiver radio impairments with no dedicated analog circuit in the feedback loop. Based on a unified time-domain approach, the proposed method is able to calibrate jointly the frequency-independent I-Q imbalance, frequency-dependent I-Q imbalance and dc offset and is applicable to any type of communication systems (single-carrier, multiple-carrier, etc.). The existing methods in the literature either need a dedicated analog circuit in the feedback loop and/or are applicable only to a particular type of systems with some radio impairments present. The issue of training sequence design is also investigated to optimize the calibration performance, and analytical and simulation results show that the performance loss due to radio impairments can be recovered by the proposed method. © 2012 IEEE. Source

Chiang C.,National Chiao Tung University
International Journal of Production Economics | Year: 2013

Most periodic review models in the inventory literature have assumed a fixed length of the review periods. In this note, we extend the work of Chiang (2008), and consider backlogged and lost-sales periodic review models where the review periods are of a variable length and there is a fixed cost of ordering for replenishment. Assuming that period lengths are independently and identically distributed, we show (using an exact method of computing inventory holding costs) that an (s, S) policy is optimal for the infinite horizon problem. The periodic review policies developed are thus easy to implement. The computation shows that if the fixed cost of ordering is small, one needs to use the proposed periodic policies. © 2013 Elsevier B.V. Source

Hsu C.C.,National Chiao Tung University
Displays | Year: 2012

Besides usability, visual aesthetics also strongly influence whether users will continue to trust and use a website. This study examined blogs to determine whether a correlation exists between the gender and visual preferences of young people toward blog interfaces. Few research on gender differences in visual preferences for blog interfaces have been published. Therefore the goal of this research is to determine the different design features of blog interfaces preferred by males and females. Using two Multidimensional Scaling (MDS) algorithms, ALSCAL and PREFMAP analysis, the perceptual space of user blog interface preferences was plotted to explore the hidden perceptual configuration of users as well as examine gender related ideal points. The results showed four typical blog interfaces and three dimensions that affected user preference and the spatial distribution of ideal preference point for each user. Last, gender differences in the blog interface preference of young people were discussed and guidelines were recommended for developers. The results are applicable to blog interface customization in digital device displays. © 2012 Elsevier B.V. All rights reserved. Source

Ke J.-C.,National Taichung Institute of Technology | Wu C.-H.,National Chiao Tung University
Computers and Industrial Engineering | Year: 2012

This paper investigates a machine repair problem with homogeneous machines and standbys available, in which multiple technicians are responsible for supervising these machines and operate a (R, V, K) synchronous vacation policy. With such a policy, if any V idle technicians exist in the system, these V (V < R) technicians would take a synchronous vacation. Upon returning from vacation, they would take another vacation if there is no broken machine waiting in the queue. This pattern continues until at least one failed machine arrives. It is assumed that the number of teams/groups on vacation is less than or equal to K (0 ≦ KV < R). The matrix analytical method is employed to obtain a steady-state probability and the closed-form expression of the system performance measures. Efficient approaches are performed to deal with the optimization problem of the discrete/continuous variables while maintaining the system availability at a specified acceptable level. Source

Chang S.-W.,Academia Sinica, Taiwan | Chang S.-W.,National Chiao Tung University
Optics Express | Year: 2012

We propose a chiral Fabry-Perot cavity in which only the cavity modes in almost pure spin (circular polarization) states lase in the presence of gain. In absence of imposed nonreciprocal environments and time-reversal symmetry breaking of emitter states to favor the emission of circularly-polarized photons, only the resonance of modes with a specific spin orientation remains in the cavity. We demonstrate a prototype of the cavity using distributed Bragg reflectors and cholesteric liquid crystals. This reciprocal cavity may provide a method to control the angular momentum state of emitters based on stimulated emissions. © 2012 Optical Society of America. Source

Wang C.-H.,National Chiao Tung University
International Journal of Production Research | Year: 2013

In an era of global customisation, buyers continuously benefit from the flexibility of selecting their desired options when making decisions on purchasing. Most manufacturing companies, however, need to balance the trade-offs between enhancing product variety and controlling manufacturing cost. In order to fulfil the goal of market-oriented product development, customer satisfaction needs to be well incorporated into the decision-making process of product configuration. Therefore, a hybrid framework is presented to address two critical issues in new product development: customer satisfaction and product configuration. In the beginning, fuzzy Kano model is employed to elicit customer perception of product attributes and extract customer satisfaction. Consecutively, information entropy is used for deriving the important weights of product attributes. Lastly, by means of Technique for Order Preference by Similarity to Ideal Solution, competing design alternatives are efficiently prioritised and configured. In particular, a case study on configuring varieties of smart pads is demonstrated to justify the validity of the proposed framework. With consideration of and the pricing policies of multi-segments, a systematic framework to effectively bridge customer satisfaction and product configuration is offered for the academics and industrial practitioners. © 152013 © 2013 Taylor & Francis. Source

Jeng D.J.-F.,National Cheng Kung University | Tzeng G.-H.,National Chiao Tung University | Tzeng G.-H.,Kainan University
Computers and Industrial Engineering | Year: 2012

The aim of study is to examine whether social influence affects medical professionals' behavioral intention to use while introducing a new Clinical Decision Support System (CDSS). The series of Technology Acceptance Models (TAMs) have been widely applied to examine new technology acceptance by scholars; nevertheless, these models omit system diversity and the user's profession. On the other hand, causal analysis greatly affects the efficiency of decision-making, and it is usually analyzed by Structural Equation Modeling (SEM); however, the method is often misapplied. This research applies the Decision-Making Trial and Evaluation Laboratory (DEMATEL) technique to explore the causal relationship between the significant Unified Theory of Acceptance and Use of Technology (UTAUT) variables. Fuzzy concept is applied to illustrate human vague judgment. It is significant that, in contrary with UTAUT, this study found that social influence does not matter in the behavioral intention to use the CDSS for medical professionals. © 2011 Elsevier Ltd. All rights reserved. Source

Hong H.-C.,National Chiao Tung University
IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems | Year: 2012

This paper proposes a static linear behavior (SLB) analog fault model for switched-capacitor (SC) circuits. The SC circuits under test (CUT) are divided into functional macros including the operational amplifiers, the capacitors, and the switches. Each macro has specified design parameters from the design's perspectives. These design parameters constitute a parameter set which determines the practical transfer function of the CUT. The SLB fault model defines that a CUT is faulty if its parameter set results in transfer functions whose frequency responses are out of the design specification. We analyzed the fault effects of the macros and derived their faulty signal-flow graph models with which the faulty transfer function templates of the CUT can be automatically generated. Based on the templates, we proposed a test procedure that can estimate all the parameters in the parameter set so as to test the CUT with multiple faults. Different from conventional single fault assumption, the proposed SLB fault model covers concurrent multiple parametric faults and catastrophic faults. In addition, it does not need to conduct fault simulations before test as conventional analog fault models do. As a result, it addresses the impractically long fault simulation time issue. A fully-differential low-pass SC biquad filter was adopted as an example to demonstrate how to design and use efficient multitone tests to test for the parameter set. The multitone test results acquired during the test procedure also reveal the distortion and noise performance of the CUT though the SLB fault model does not include them. © 2012 IEEE. Source

Werner D.,Tokushima University | Hashimoto S.,Tokushima University | Uwada T.,National Chiao Tung University
Langmuir | Year: 2010

An in situ spectroscopic study of the nanosecond laser-induced melting and size reduction of pseudospherical gold nanoparticles with 54 ± 7 nm diameter allowed the observation of a heating efficiency that was very dependent on the excitation wavelength.A remarkably greater efficiency was observed for the photothermal effect of interband excitation than that of intraband excitation. This noteworthy observation is ascribed to an altered electron heat capacity, ce, during photoexcitation depending on the excitation energy, which is a phenomenon that has not been realized previously. As a result, a 60% reduction of the specific heat capacity, cp, compared to that of bulk gold was obtained for interband excitation at 266 nm whereas the cp value for the excitation of the intraband transition at 532 nm was unaltered. A semiquantitative explanation was given for this striking phenomenon induced by interband excitation in which excitation-relaxation cycles of electrons upon excitation of 5d electrons to the 6sp band lead to a reduced number of electrons contributing to the electron temperature rise in the vicinity of the Fermi level during the nanosecond laser pulse duration. By contrast, electronic excitation within the 6sp band results in no net reduction in the number of electrons near the Fermi level, giving rise to a value of cp similar to that of bulk gold. Our finding that the heat capacity of gold nanoparticles can be changed upon UV laser excitation is important for understanding the fundamental nature of noble metal nanoparticles. Furthermore, this finding might be useful for preparing new metal alloy particles as well as for manipulating the thermodynamic properties of the nanoparticles. © 2010 American Chemical Society. Source

Different from previous works, this paper considers the router node placement of wireless mesh networks (WMNs) in a dynamic network scenario in which both mesh clients and mesh routers have mobility, and mesh clients can switch on or off their network access at different times. We investigate how to determine the dynamic placement of mesh routers in a geographical area to adapt to the network topology changes at different times while maximizing two main network performance measures: network connectivity and client coverage, i.e., the size of the greatest component of the WMN topology and the number of the clients within radio coverage of mesh routers, respectively. In general, it is computationally intractable to solve the optimization problem for the above two performance measures. As a result, this paper first models a mathematical form for our concerned problem, then proposes a particle swarm optimization (PSO) approach, and, from a theoretical aspect, provides the convergence and stability analysis of the PSO with constriction coefficient, which is much simpler than the previous analysis. Experimental results show the quality of the proposed approach through sensitivity analysis, as well as the adaptability to the topology changes at different times. © 2013 Elsevier Inc. All rights reserved. Source

Kuo H.-Y.,National Chiao Tung University
International Journal of Engineering Science | Year: 2011

A theoretical framework is developed to investigate the magnetoelectroelastic potential in a multicoated elliptic fibrous composite with piezoelectric and piezomagnetic phases. We generalize the classic work of Rayleigh (1892) to obtain the electrostatic potential in ordered conductive composites and its extension to a disordered system (Kuo, 2010; Kuo & Chen, 2008) to the current coupled magnetoelectroelastic multicoated elliptic composites. We combine the methods of complex potentials with a re-expansion formulae and the generalized Rayleigh's formulation to obtain a complete solution of the multi-field many-inclusion problem. It is shown that the coefficients of field expansions can be written in the form of an infinite set of linear algebraic equations. Numerical results are presented for several configurations. We use this method to study BaTiO3-CoFe 2O4 composites and find that, with appropriate coating, the effective magnetoelectric voltage coefficient can be enhanced with one order of magnitude compared to their non-coating counterpart. © 2011 Elsevier Ltd. All rights reserved. Source

Lee Y.-S.,National Taiwan Normal University | Tong L.-I.,National Chiao Tung University
Applied Energy | Year: 2012

Energy consumption is an important index of the economic development of a country. Rapid changes in industry and the economy strongly affect energy consumption. Although traditional statistical approaches yield accurate forecasts of energy consumption, they may suffer from several limitations such as the need for large data sets and the assumption of a linear formula. This work describes a novel hybrid dynamic approach that combines a dynamic grey model with genetic programming to forecast energy consumption. This proposed approach is utilized to forecast energy consumption because of its excellent accuracy, applicability to cases with limited data sets and ease of computability using mathematical software. Two case studies of energy consumption demonstrate the reliability of the proposed model. Computational results indicate that the proposed approach outperforms other models in forecasting energy consumption. © 2012. Source

Lin F.C.,National Chiao Tung University
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference | Year: 2012

With brain-computer interface (BCI) applications in mind, we analyzed the amplitudes and the signal-to-noise ratios (SNR) of steady-state visual evoked potentials (SSVEP) induced in the foveal and extra-foveal regions of human retina. Eight subjects (age 20-55) have been exposed to 2° circular and 16°-18° annular visual stimulation produced by white LED lights flickering between 5Hz and 65Hz in 5Hz increments. Their EEG signals were recorded using a 64-channel NeuroScan system and analyzed using non-parametric spectral and canonical convolution techniques. Subjects' perception of flickering and their levels of comfort towards the visual stimulation were also noted. Almost all subjects showed distinctively higher SNR in their foveal SSVEP responses between 25Hz and 45Hz. They also noticed less flickering and felt more comfortable with the visual stimulation between 30Hz and 45Hz. These empirical evidences suggest that lights flashing above the critical flicker fusion rates (CFF) of human vision may be used as effective and comfortable stimuli in SSVEP BCI applications. Source

Lee W.-C.,Feng Chia University | Chung Y.-H.,National Chiao Tung University
International Journal of Production Economics | Year: 2013

Scheduling with learning effects has received considerable attention recently. Often, numbers of operations have to be done on every job in many manufacturing and assembly facilities. However, it is seldom discussed in the general multiple-machine setting, especially without the assumptions of identical processing time on all the machines or dominant machines. With the current emphasis of customer service and meeting the promised delivery dates, we consider a permutation flowshop scheduling problem with learning effects where the objective is to minimize the total tardiness. A branch-and-bound algorithm and two heuristic algorithms are established to search for the optimal and near-optimal solutions. Computational experiments are also given to evaluate the performance of the algorithms. © 2012 Elsevier B.V. All rights reserved. Source

Chen P.-H.,National Chiao Tung University
Behavior research methods | Year: 2015

Existing automated test assembly methods typically employ constrained combinatorial optimization. Constructing forms sequentially based on an optimization approach usually results in unparallel forms and requires heuristic modifications. Methods based on a random search approach have the major advantage of producing parallel forms sequentially without further adjustment. This study incorporated a flexible content-balancing element into the statistical perspective item selection method of the cell-only method (Chen et al. in Educational and Psychological Measurement, 72(6), 933-953, 2012). The new method was compared with a sequential interitem distance weighted deviation model (IID WDM) (Swanson & Stocking in Applied Psychological Measurement, 17(2), 151-166, 1993), a simultaneous IID WDM, and a big-shadow-test mixed integer programming (BST MIP) method to construct multiple parallel forms based on matching a reference form item-by-item. The results showed that the cell-only method with content balancing and the sequential and simultaneous versions of IID WDM yielded results comparable to those obtained using the BST MIP method. The cell-only method with content balancing is computationally less intensive than the sequential and simultaneous versions of IID WDM. Source

Hsieh W.Y.,National Chiao Tung University
International journal of biological sciences | Year: 2012

Pleural effusion is common problem, but the rapid and reliable diagnosis for specific pathogenic effusions are lacking. This study aimed to identify the diagnosis based on clinical variables to differentiate pleural tuberculous exudates from other pleural effusions. We also investigated the role of renin-angiotensin system (RAS) and matrix metalloproteinase (MMPs) in the pathogenesis of pleural exudates. The major components in RAS and extracellular matrix metabolism, including angiotensin converting enzyme (ACE), ACE2, MMP-2 and MMP-9 activities, were measured and compared in the patients with transudative (n = 45) and exudative (n = 80) effusions. The exudative effusions were come from the patients with tuberculosis (n = 20), pneumonia (n = 32), and adenocarcinoma (n = 28). Increased ACE and equivalent ACE2 activities, resulting in a significantly increased ACE/ACE2 ratio in exudates, were detected compared to these values in transudates. MMP-9 activity in exudates was significantly higher than that in transudates. The significant correlation between ACE and ACE2 activity that was found in transudates was not found in exudates. Advanced analyses showed significantly increased ACE and MMP-9 activities, and decreased ACE2 activity in tuberculous pleural effusions compared with those in pneumonia and adenocarcinoma effusions. The results indicate that increased ACE and MMP-9 activities found in the exudates were mainly contributed from a higher level of both enzyme activities in the tuberculous pleural effusions. Interplay between ACE and ACE2, essential functions in the RAS, and abnormal regulation of MMP-9 probably play a pivotal role in the development of exudative effusions. Moreover, the ACE/ACE2 ratio combined with MMP-9 activity in pleural fluid may be potential biomarkers for diagnosing tuberculous pleurisy. Source

Xu M.,Chonbuk National University | Ren H.,Chonbuk National University | Lin Y.-H.,National Chiao Tung University
Optics Letters | Year: 2015

We report an adaptive iris using dielectric liquids and a radial-interdigitated electrode. A black liquid is confined by a circular gasket with a donut shape. The surrounding of the black liquid is filled with an immiscible liquid. In the relaxing state, the black liquid obtains the largest clear aperture. By applying a voltage, the surface of the black liquid is stretched by the generated dielectric force, resulting in a reduction of its aperture. For the demonstrated iris, the diameter of the aperture can be changed from ∼4.7 mm to ∼1.2 mm when the voltage is applied from 0 to 70 Vrms. The aperture ratio is ∼94%. Owing to the radial-interdigitated electrode, the aperture size of the iris can be effectively switched with a reasonably fast response time. The optical switch is polarization-insensitive. The potential applications of our iris are light shutters, optical attenuators, biomimicry, and wearable devices. © 2015 Optical Society of America. Source

Ou Yang Y.-P.,National Central University | Shieh H.-M.,National Central University | Tzeng G.-H.,Kainan University | Tzeng G.-H.,National Chiao Tung University
Information Sciences | Year: 2013

As companies and organizations have grown to rely on their computer systems and networks, the issue of information security management has become more significant. To maintain their competitiveness, enterprises should safeguard their information and try to eliminate the risk of information being compromised or reduce this risk to an acceptable level. This paper proposes an information security risk-control assessment model that could improve information security for these companies and organizations. We propose an MCDM model combining VIKOR, DEMATEL, and ANP to solve the problem of conflicting criteria that show dependence and feedback. In addition, an empirical application of evaluating the risk controls is used to illustrate the proposed method. The results show that our proposed method can be effective in helping IT managers validate the effectiveness of their risk controls. © 2013 Elsevier Inc. All rights reserved. Source

National Chiao Tung University | Date: 2013-10-07

A wavelength-division multiplexing (WDM) optical fiber network system is disclosed, which comprises a signal provider generating at least one set of wavelength signals of a plurality of different wavelengths and coupled to a plurality of modulation modules. The modulation modules respectively coupled to a user receiver. The modulation module comprises a control unit generating a random sequence and a control signal corresponding to the random sequence, and transmitting the control signal to a first modulation unit. The control unit is coupled to the signal provider to receive the wavelength signals and controls the first modulation to retrieve a wavelength signal according to the control signal. The control unit rapidly changes the control signal according to the random sequence whereby the first modulation unit rapidly retrieves the wavelength signals of different wavelengths and transmits them to the user receiver, so as to prevent a specific wavelength from attack.

National Chiao Tung University | Date: 2014-08-22

A resource allocation server and a communication system are provided. The server receives location data of the access points (APs) and channel request data of the APs corresponding to the location data of the APs. The server groups the channel request data of the APs into clusters according to available physical channels of the APs and the channel request data of the APs. The server allocates the available physical channels of the APs for the channel request data of the APs and transmission power configurations on each of the allocated physical channels of the APs according to the channel request data and the location data of the APs in each of the clusters. The server transmits allocated results of the allocated physical channels of the APs for the channel request data of the APs and the transmission power configurations on each of the allocated physical channels of the APs.

National Chiao Tung University | Date: 2014-02-26

A method for forming a GaN-containing semiconductor structure is provided. The method comprises a substrate is provided, a nucleation layer is formed above the substrate, a diffusion blocking layer is formed above the nucleation layer, a strain relief layer is formed above the diffusion blocking layer, and a semiconductor layer is formed above the strain relief layer, in which the diffusion blocking layer is deposited on the nucleation layer such that the diffusion blocking layer can prevent the impurities out-diffusion from the substrate.

National Chiao Tung University | Date: 2013-10-30

The present invention discloses a portable noninvasive inspection device, which comprises a light source illuminates an target to generate an optical inspection signal; a probe head provides an optical path for said light source to receive said optical inspection signal; at least one switched filter module arranged in the optical path, allowing the optical inspection signal to pass therethrough to generate a corresponding spectral signal; and an image sensor arranged behind the switched filter module, receiving the spectral signal and generating a spectral image. The spectral image can be transmitted to an external device, wherefrom the user can use the spectral image to examine the target in further detail. The present invention features a rotary-type or movable-type switched filter module, which facilitates the user to switch filters easily during optical inspection and expands the application of the present invention.

National Chiao Tung University | Date: 2011-05-20

The present invention provides a carrier component. The carrier component includes a carrier core body including a dispersive object and a dualistic self-assembly material for encapsulating the dispersive object, wherein the dualistic self-assembly material has an electric charge; and a first shell layer having an electric charge opposite to the electric charge of the dualistic self-assembly material, and coating the carrier core body, and thus avoids inactivation of a medicine, eliminates medicine leakage and reduces medicine releasing. The present invention further provides a method for forming a carrier component.

A nano-photoacoustic imaging agent is disclosed. The nano-photoacoustic imaging agent includes a porous carrier and a gold filling material embedded in the porous carrier. A method for the preparation of the nano-photoacoustic imaging agent is also provided.

National Chiao Tung University | Date: 2013-03-14

A three-dimensional integrated circuit, including a first adhesive bonding layer, a first chip, a second chip, and an inter-stratum thermal pad, is provided. The first adhesive bonding layer has a first surface and a second surface opposite to each other. The first chip is disposed on the first surface of the first adhesive bonding layer. The first chip includes a hot zone. The second chip is disposed on the second surface of the first adhesive bonding layer. The inter-stratum thermal pad is embedded in the first adhesive bonding layer and faces to the hot zone.

National Chiao Tung University | Date: 2011-09-07

A method for growing a Group III-V nitride film and a structure thereof are presented. The method is carried out by hydride vapor phase epitaxy (HVPE). The method includes the steps of, inter alia, slowly epitaxially growing a temperature ramping nitride layer on a substrate by rising a first growth temperature of 900-950 C. to a second growth temperature of 1000-1050 C. at a temperature-rising rate of 0.5-10 C./min. The lattice quality of the temperature ramping nitride layer is slowly transformed with the layer height, so that a stress induced by lattice mismatch between a sapphire substrate and a gallium nitride (GaN) layer is relieved.

National Chiao Tung University and United Microelectronics | Date: 2013-07-31

An electrostatic discharge (ESD) protection circuit, suitable for an input stage circuit including a first N channel metal oxide semiconductor (NMOS) transistor, is provided. The ESD protection circuit includes an P channel metal oxide semiconductor (PMOS) transistor and an impedance device, in which the PMOS transistor has a source coupled to a gate of the first NMOS transistor, and a drain coupled to a source of the first NMOS transistor, and the impedance device is coupled between a gate of the PMOS transistor and a first power rail to perform a initial-on ESD protection circuit. The ESD protection circuit formed by the PMOS transistor and the resistor is capable of increasing the turn-on speed of the ESD protection circuit and preventing the input stage circuit from a CDM ESD event.

The present invention provides a method for manufacturing platinum nanoparticle solution and a self-assembled platinum counter electrode thereof. The present invention adopts a polyol reduction method and controls the reduction reaction periods under various pH conditions. After the platinum nanoparticle dispersion solution of uniformly distributed platinum nanoparticles having small sizes is produced, the self-assembled platinum nanoparticles are adsorbed on a functionalized surface of a conductive substrate by dip coating at the normal temperature. Therefore, the structure of a platinum nanoparticle monolayer is formed, to obtain the self-assembled platinum counter electrode with a homogeneous single layer on the surface. This process is much simpler without adding any stabilizers or surfactants, without involving any subsequent heat treatments, and it consumes less amount of the platinum material. By employing the present invention for commercialization, the cost of mass production for the dye-sensitized solar cell application is thus reduced.

Hsu C.-L.,Chinese Culture University | Chen M.-C.,National Chiao Tung University
Food Quality and Preference | Year: 2014

This study examines the influence of regulatory fit on consumer attitudes and purchase intentions toward organic food and describes the moderating role of consumer characteristics. To this end, hypotheses have been developed and subjected to empirical verification using a survey. The survey results, obtained in Taiwan, provide reasonable support for the hypotheses. Specifically, the findings from the analysis of variance confirm that the occurrence of a regulatory fit leads to a more positive attitude and a greater intention to purchase organic food than when no regulatory fit occurs. Furthermore, the findings from both moderated regression analysis and simple slope analysis show that the relationships between regulatory fit and both attitude and purchase intention are moderated by consumer characteristics (i.e., trust propensity and self-confidence). Based on the findings, academic and practical implications are discussed. © 2014 Elsevier Ltd. Source

Urban P.L.,National Chiao Tung University
Journal of Chemical Education | Year: 2014

This technology report discusses the possibility of using open-source electronic platforms to enhance technology-oriented training of chemistry students at the undergraduate and graduate level. It is anticipated that the increasing availability of open-source microcontrollers and programming tools can be helpful while teaching students the principles of instrumental techniques. The implementation of such technology in training students can further assist the development of a range of complementary skills, which can readily be combined with chemistry-specific skills. © 2014 The American Chemical Society and Division of Chemical Education, Inc. Source

Bhattacherjee A.,University of South Florida | Lin C.-P.,National Chiao Tung University
European Journal of Information Systems | Year: 2015

This study presents a unified model of information technology (IT) continuance, by drawing upon three alternative influences that are presumed to shape continuance behavior: reasoned action, experiential response, and habitual response. Using a longitudinal survey of workplace IT continuance among insurance agents at a large insurance company in Taiwan, we demonstrate that the above influences are interdependent, complementary, and have crossover effects. This study advances IT continuance research by theorizing and validating a unifying model that extends prior perspectives and by explaining interrelationships between these perspectives. © 2015 Operational Research Society Ltd. All rights reserved. Source

National Chiao Tung University | Date: 2012-07-17

A light emitting device with graded composition hole tunneling layer is provided. The device comprises a substrate and an n-type semiconductor layer is disposed on the substrate, in which the n-type semiconductor layer comprises a first portion and a second portion. A graded composition hole tunneling layer is disposed on the first portion of the n-type semiconductor layer. An electron blocking layer is disposed on the graded composition hole tunneling layer. A p-type semiconductor layer is disposed on the electron blocking layer. A first electrode is disposed on the p-type semiconductor layer, and a second electrode is disposed on the second portion of the n-type semiconductor layer and is electrical insulated from the first portion of the n-type semiconductor. The graded composition hole tunneling layer is used as the quantum-well to improve the transport efficiency of the holes to increase the light emitting efficiency of the light emitting device.

A manufacturing method of a device having series-connected HEMTs is presented. Transistors are formed on a substrate and integratedly serial-connected as an integrated device by interconnection wires. Therefore, the voltage of the device is the sum of the voltages across each transistors so that the device can have high breakdown voltage.

National Chiao Tung University | Date: 2011-02-01

The present invention discloses a frame prediction system and a prediction method thereof. An initializing module initializes a first image block having a plurality of pixels. A providing module provides a first centroid and a first motion vector of a second image block. The location lookup module finds a location according to the first centroid, and generates a first weight and a second weight respectively according to a relationship between each of the pixels, the first centroid and the location. A vector lookup module finds a second motion vector, which gives a minimum pixel intensity error for the plurality of pixels in the first image block according to the first centroid, the first motion vector, the location, the first weight and the second weight. A processing module sequentially calculates a plurality of predictive intensity values according to the motion vectors and the weights.

National Chiao Tung University | Date: 2011-07-07

A speech recognition device and a speech recognition method thereof are disclosed. In the speech recognition method, a key phrase containing at least one key word is received. The speech recognition method comprises steps: receiving a sound source signal of a key word and generating a plurality of audio signals; transforming the audio signals into a plurality of frequency signals; receiving the frequency signals to obtain a space-frequency spectrum and an angular estimation value thereof; receiving the space-frequency spectrum to define and output at least one spatial eigenparameter and, and using the angular estimation value and the frequency signals to perform spotting and evaluation and outputting a Bhattacharyya distance; and receiving the spatial eigenparameter and the Bhattacharyya distance and using corresponding thresholds to determine correctness of the key phrase. Thereby this invention robustly achieves high speech recognition rate under very low SNR conditions.

National Chiao Tung University | Date: 2014-04-24

An antibody-conjugated double-emulsion nanocapsule is provided. A linking group is introduced on the surface of a double-emulsion nanocapsule, which is composed of an oily shell enclosing an aqueous core, to link the double-emulsion nanocapsule with an antibody.

National Chiao Tung University | Date: 2013-11-08

A method for fabricating a thin-film transistor is disclosed. Firstly, a patterned dielectric mask structure with a bottom thereof having a gate dielectric layer is formed on a gate-stacked structure so that the gate dielectric layer covers a gate of the gate-stacked structure. Top surface of the patterned dielectric mask structure has at least two openings. A semiconductor layer is formed on the gate-stacked structure via the openings by a sputtering method. The semiconductor layer comprises a channel above the gate, a source and a drain below the openings. The channel has a thickness which sequentially decreases from edge to center.

National Chiao Tung University | Date: 2012-11-16

A motion parameter estimating method, an angle estimating method and a determination method are provided. The methods are adapted for an electronic device. In the angle estimating method, a first frequency modulation continuous wave signal is first transmitted, and at least one antenna receives a second frequency modulation continuous wave signal resulted by a target reflecting the first frequency modulation continuous wave signal. Multiple motion parameters associated with the target are then obtained according to the first frequency modulation continuous wave signal and the second frequency modulation continuous wave signal. Multiple measured values corresponding to the at least one antenna are obtained according to the motion parameters and configuration parameters of the at least one antenna, respectively. Afterwards, the measured values are substituted into a formula to obtain an estimated angle between a preset direction of the electronic device and the target.

National Chiao Tung University | Date: 2011-05-18

The invention discloses a smoothing method to decrease bowing of group III nitride semiconductor substrate. The certain face of group III nitride semiconductor substrates is etched under the appropriate etching recipe and time, the certain morphology such as rod-type and other structures are appeared at the certain face. And such structures releases the compressive stresses at these certain faces, resulting in clearly increasing the bowing radius of the group III nitride semiconductor substrates, finally decreasing the bowing phenomenon of the group III nitride semiconductor substrate.

National Chiao Tung University | Date: 2011-09-23

An innovative dual-port subthreshold static random access memory (SRAM) cell for sub-threshold voltage operation is disclosed. During write mode, the dual-port subthreshold SRAM cell would cut off the positive feedback loop of the inverters and utilize the reverse short-channel effect to enhance write capability. The single-ended read/write port structure further reduces power consumption of the lengthy bit line. Therefore, the dual-port subthreshold SRAM cell is a suitable for long operation in a first-in first-out memory system. Although the lower voltage reduces the stability of the memory cell, the dual-port subthreshold SRAM cell of the present invention can still stably operate.

National Chiao Tung University | Date: 2014-01-30

The present invention provides a communication system between electric bikes and communication method thereof. The communication system comprises a plurality of electric bikes. Each of the electric bikes comprises a monitor module and a portable electric device, wherein the portable device further comprises a storing unit and a WiFi module. The monitor module is configured to monitor the status of the electric bike to generate a plurality of monitor information. When a temporary network is formed between the electric bikes, the electric bikes transmit the monitor information each other through the temporary network and each of the electric bikes stores the received monitor information.

The invention provides a phase-locked loop with loop gain calibration and methods for measuring an oscillator gain, gain calibration and jitter measurement for a phase-locked loop. The method for measuring an oscillator gain of a phase-locked loop includes the steps of providing a varying code at an input end of the oscillator; outputting excess reference phase information by a reference phase integral path and outputting excess feedback phase information based on the varying code by a feedback phase integral path; and obtaining an estimated gain information of the oscillator based on the excess reference phase information and the excess feedback phase information.

In a cooperative spectrum sensing method and system for locationing primary transmitters, each of secondary users transmits to a corresponding one of cognitive radio (CR) base station location information thereof and a received signal strength indicator (RSSI) value generated thereby in response to sensing power signals from the primary transmitters. The CR base stations transmit the location information and the RDDI values of the secondary users to a data fusion center such that the data fusion center obtains the number and locations of the primary transmitters based on the location information and the RSSI values received thereby using a learning algorithm to thereby reconstruct a power propagation map of the primary transmitters.

National Chiao Tung University and Faraday Technology Corporation | Date: 2011-01-19

A Random Access Memory (RAM) with a plurality of cells is provided. In an embodiment, the cells of a same column are coupled to a same pair of bit-lines and are associated to a same power controller. Each cell has two inverters; the power controller has two power-switches. For the cells of the same column, the two power-switches respectively perform independent supply voltage controls for the two inverters in each cell according to data-in voltages of the bit-lines during Write operation.

National Chiao Tung University | Date: 2012-04-16

A piezoelectric panel speaker and an optimal method of designing the same is disclosed. In the structure of the speaker, at least one piezoelectric plate attached at a surrounding frame supports a diaphragm inside the surrounding frame. A spacer is inserted between the piezoelectric plate and the diaphragm. The structure of the piezoelectric plates fixed at the surrounding frame improves the speaker performance within the low frequency range. The finite element method is employed to build a mathematical model to simulate the sound pressure loading of the piezoelectric panel speaker. Also, the simulated annealing method is employed to approach the optimal design parameters of the speaker structure.

National Chiao Tung University | Date: 2014-11-28

An antenna includes a pair of first and second slot antenna bodies that integrally intersect each other and that are perpendicular to each other. The first and second slot antenna bodies are adapted to respectively receive a first radio frequency (RF) signal and a second RF signal that have the same magnitude and a 90-degree phase difference. Upon receipt of the first and second RF signals, the antenna is capable of producing a horizontally polarized omnidirectional radiation pattern.

National Chiao Tung University | Date: 2014-03-10

A method for fabricating anisotropic polymer particles comprises steps: providing a first substrate; arranging a plurality of polymer spheres on the first substrate; providing a second substrate to cover the polymer spheres; heating at least one of the first substrate, the second substrate, and the polymer spheres; and applying force to the first substrate and the second substrate to squeeze the polymer spheres into a plurality of anisotropic polymer particles. The present invention uses simple compressing and heating processes to fabricate many types of anisotropic polymer structures and thus saves the cost and time of fabrication.

National Chiao Tung University | Date: 2013-06-28

An ECO hold time fixing method fulfills a short path padding in a placed and routed design by a minimum capacitance insertion. In the method, a padding value determination step receives the placed and routed design and is based on a cell library, timing constraints, and a timing analysis report to determine padding values and locations required for each gate of the placed and routed design to output. A load/buffer allocation step is based on a spare cell information, a dummy metal information, and the padding values and locations to achieve the short path padding in the placed and routed design.

A yellow phosphor having oxyapatite structure, preparation method and white light-emitting diode thereof are disclosed. The yellow phosphor has a chemical formula of (A

National Chiao Tung University | Date: 2012-05-31

The present invention relates to an on-chip electronic device and a method for manufacturing the same. The on-chip electronic device according to the present invention comprises a substrate, a porous layer, a plurality of magnetic bodies, and an electronic member layer. The porous layer is disposed on the substrate and has a plurality of voids; each of the plurality of magnetic bodies is disposed in the plurality of voids, respectively; and the electronic member layer is disposed on one side of the porous layer, such as upper side of or lower sider of the porous layer. Because the plurality of magnetic bodies is used as the core of the inductance, the inductance is increased effectively and the area of the on-chip electronic device is reduced. Besides the manufacturing method according to the present invention is simple and compatible with the current CMOS process, the manufacturing cost can be lowered.

National Chiao Tung University | Date: 2011-03-05

An electrostatic discharge (ESD) protection structure for a 3D IC is provided. The ESD protection structure includes a first active layer, a through-silicon via (TSV) device and a second active layer. The TSV is disposed in the first active layer, and the second active layer is stacked with the first active layer. The second active layer includes a substrate and an ESD protection device, wherein the ESD protection device having a doping area embedded in the substrate, and the ESD protection device electrically connects the TSV device.

National Chiao Tung University | Date: 2012-03-14

A multi-filter PM 10-PM 2.5 sampler which enable the simultaneous collection of four PM 10 and four PM 2.5 samples is disclosed. The sampler is provided with a PM 10 impactor to remove coarse particles and operates at 33.4 L/min. After the PM 10 impactor, the aerosol flow is divided by half by a branch pipe. Half of the flow is directed into four PM 10 cassettes, while the other half is directed into four PM 2.5 cassettes after the aerosols are further classified by a PM 2.5 impactor. To ensure the aerosol flow uniformly passes through each of the four PM 10 or four PM 2.5 cassettes, an orifice plate is assembled behind each of the filter cassettes to increase the pressure drop, such that the flow rates of eight sampling lines are nearly equal.

An all-digital clock generator includes a digitally-controlled clock generator and a processing unit. The digitally-controlled clock generator generates a clock signal in response to an enable signal and a digital signal. The processing unit has a frequency multiplier and a reference signal having a period, digitizes the period to generate a quantized signal, generates the digital signal according to the quantized signal and the frequency multiplier, and generates the enable signal according to the reference signal, the clock signal and the frequency multiplier.

National Chiao Tung University | Date: 2012-01-18

A delay cell includes a first inverted transistor pair, a second inverted transistor pair and a plurality of delay units. The first inverted transistor pair is used to receive an input signal. The second inverted transistor pair is electrically cross-coupled to the first inverted transistor pair and cross-controlled by the first inverted transistor pair. The delay units are cascaded between the first inverted transistor pair and between the second inverted transistor pair, thereby providing a plurality of signal propagation delays sequentially, wherein the input signal is delayed for a pre-determined time by the first inverted transistor pair, the second inverted transistor pair and the delay units which are operated sequentially, thereby creating an output signal corresponding to the pre-determined time. A digitally controlled oscillator including the aforementioned delay cells is provided.

National Chiao Tung University | Date: 2012-01-17

A microalgae cultivation module for carbon reduction and biomass production is provided, which includes a first photobioreactor set, a second photobioreactor set, a gas switching device and a control unit. The gas switching device is communicated to the first and the second photobioreactor sets. The control unit is coupled to and controls the gas switching device, thereby aerating a waste gas into the first photobioreactor set and aerating air into the second photobioreactor set for a first predetermined time, then aerating the waste gas into the second photobioreactor set and aerating the air into the first photobioreactor set for a second predetermined time. The first and the second photobioreactor sets include a microalgae species.

The present invention provides a 6T SRAM including a first inverter, a second inverter, a first pass-gate transistor, and a second pass-gate transistor. The first inverter zs a first pull-up transistor and a first pull-down transistor. The second inverter includes a second pull-