Browsing by Issue Date, starting with "2012-02-29"

Now showing 1 - 20 of 37245

TWO NEW SANDPERCHES (PERCIFORMES: PINGUIPEDIDAE: PARAPERCIS) FROM SOUTH CHINA SEA, BASED ON MORPHOLOGY AND DNA BARCODING
(2012-02-29)
Ho, Hsuan-Ching
;
Chang, Chia-Hao
;
Shao, Kwang-Tsao
;
生物科技學系
;
Department of Biological Science and Technology
Two new cryptic sandperch species of the pinguipedid genus Parapercis are described from off southern Taiwan, northern South China Sea. Parapercis kentingensis n. sp., described from 25 specimens, is morphologically similar to P shaoi Randall, 2008. Parapercis rubromaculata n. sp., described from four specimens, is morphologically similar to P randalli Ho & Shao, 2010. The four species have sympatric distributions in southern Taiwan. Both new species differ from their congeners in colouration and a combination of other characters. Morphological evidence for establishing new species status is also supported by DNA barcoding.
Structural and morphological transformations of TiO2 nanotube arrays induced by excimer laser treatment
(2012-02-29)
Hsu, Ming-Yi
;
Nguyen Van Thang
;
Wang, Chih
;
Leu, Jihperng
;
材料科學與工程學系
The structural and morphological transformations of TiO2 nanotube arrays (TNAs) treated by excimer laser annealing (ELA) were investigated as a function of the laser fluence using parallel and tilted modes. Results showed that the crystallinity of the ELA-treated TNAs reached only about 50% relative to that of TNAs treated by furnace anneal at 400 degrees C for 1 h. The phase transformation starts from the top surface of the TNAs with surface damage resulting from short penetration depth and limited one-dimensional heat transport from the surface to the bottom under extremely short pulse duration (25 ns) of the excimer laser. When a tilted mode was used, the crystallinity of TNAs treated by ELA at 85 degrees was increased to 90% relative to that by the furnace anneal. This can be attributed to the increased area of the laser energy interaction zone and better heat conduction to both ends of the TNAs. (c) 2011 Elsevier B.V. All rights reserved.
Core Site-Moiety Maps Reveal Inhibitors and Binding Mechanisms of Orthologous Proteins by Screening Compound Libraries
(2012-02-29)
Hsu, Kai-Cheng
;
Cheng, Wen-Chi
;
Chen, Yen-Fu
;
Wang, Hung-Jung
;
Li, Ling-Ting
Members of protein families often share conserved structural subsites for interaction with chemically similar moieties despite low sequence identity. We propose a core site-moiety map of multiple proteins (called CoreSiMMap) to discover inhibitors and mechanisms by profiling subsite-moiety interactions of immense screening compounds. The consensus anchor, the subsite-moiety interactions with statistical significance, of a CoreSiMMap can be regarded as a "hot spot" that represents the conserved binding environments involved in biological functions. Here, we derive the CoreSiMMap with six consensus anchors and identify six inhibitors (IC50 < 8.0 mu M) of shikimate kinases (SKs) of Mycobacterium tuberculosis and Helicobacter pylori from the NCI database (236,962 compounds). Studies of site-directed mutagenesis and analogues reveal that these conserved interacting residues and moieties contribute to pocket-moiety interaction spots and biological functions. These results reveal that our multi-target screening strategy and the CoreSiMMap can increase the accuracy of screening in the identification of novel inhibitors and subsite-moiety environments for elucidating the binding mechanisms of targets.
A junctionless SONOS nonvolatile memory device constructed with in situ-doped polycrystalline silicon nanowires
(2012-02-29)
Su, Chun-Jung
;
Su, Tuan-Kai
;
Tsai, Tzu-I
;
Lin, Horng-Chih
;
Huang, Tiao-Yuan
In this paper, a silicon-oxide-nitride-silicon nonvolatile memory constructed on an n(+)-poly-Si nanowire [NW] structure featuring a junctionless [JL] configuration is presented. The JL structure is fulfilled by employing only one in situ heavily phosphorous-doped poly-Si layer to simultaneously serve as source/drain regions and NW channels, thus greatly simplifying the manufacturing process and alleviating the requirement of precise control of the doping profile. Owing to the higher carrier concentration in the channel, the developed JL NW device exhibits significantly enhanced programming speed and larger memory window than its counterpart with conventional undoped-NW-channel. Moreover, it also displays acceptable erase and data retention properties. Hence, the desirable memory characteristics along with the much simplified fabrication process make the JL NW memory structure a promising candidate for future system-on-panel and three-dimensional ultrahigh density memory applications.
Characterizations and thermal stability improvement of phase-change memory device containing Ce-doped GeSbTe films
(2012-02-29)
Huang, Yu-Jen
;
Tsai, Min-Chuan
;
Wang, Chiung-Hsin
;
Hsieh, Tsung-Eong
;
材料科學與工程學系
Phase-transition temperature of GeSbTe (GST) chalcogenide film was drastically increased from 159 to 236 degrees C by cerium (Ce) doping (up to 8.6 at.%) without altering the resistivity property of GST. Grain refinement via the solid-solution mechanism and the amplification of p-type semiconducting behavior in Ce-doped GST were observed. They were correlated with the enhancement of thermal stability and data retention property of GST as revealed by exothermal and isothermal analyses. Phase-change memory (PCM) device characterized at various temperatures revealed an effective thermal stability improvement on the threshold voltage of PCM device by Ce doping. (c) 2011 Elsevier B.V. All rights reserved.
Dummy-Based Schemes for Protecting Movement Trajectories
(2012-03-01)
Lei, Po-Ruey
;
Peng, Wen-Chih
;
Su, Ing-Jiunn
;
Chang, Chien-Ping
;
資訊工程學系
Dummy-based anonymization techniques for protecting the location privacy of mobile users have appeared in the literature. By generating dummies that move in human-like trajectories, this approach shows that the location privacy of mobile users can be preserved. However, the trajectories of mobile users can still be exposed by monitoring the long-term movement patterns of users. We argue that, once the trajectory of a user is identified, the locations of the user are exposed. Thus, it is critical to protect the movement trajectories of mobile users in order to preserve user location privacy. We propose two schemes that generate consistent movement patterns in the long run. Guided by three parameters in a user specified privacy profile, namely, short-term disclosure, long-term disclosure and distance deviation, the proposed schemes derive movement trajectories for dummies. The experimental results show that our proposed schemes are more effective than existing works in protecting movement trajectories.
Glass biochip fabrication by laser micromachining and glass-molding process
(2012-03-01)
Huang, Chien-Yao
;
Kuo, Chao-Hui
;
Hsiao, Wen-Tse
;
Huang, Kuo-Cheng
;
Tseng, Shih-Feng
Due to their low cost, small size, and high-speed performance, biochips are often used in various bio-experiments. Compared with polymer-based biochips, glass-based substrates are less sensitive to heat and organic environments. This study presents a hybrid processing approach that uses laser micromachining (LMM) and precision glass molding (PGM) techniques to mass-produce glass-based biochips. A silicon carbide (SiC) mold with an outside diameter of 20 mm was used to hot emboss biochip channels measuring 200 mu m wide and 185 mu m deep. This study also identifies the optimal conditions for glass molding when processing soda-lime glass for biochip applications, and discusses the influence of the major processing parameters on biochip channel depth. This study uses the Taguchi method to assess the effects of several molding parameters on larger-the-better performance characteristics. The experiments in this study consider the effects of several molding parameters, such as molding temperature, pressing force, moving speed, temperature holding time, and vacuum environment, to achieve optimum characteristics for biochip channels. Orthogonal array analysis indicates that the optimal process parameters includes a 620 degrees C molding temperature, 1 kN pressing force, 5 mm/min moving speed, 60s temperature holding time, and a vacuum-free environment. This study also investigates the surface roughness of glass biochip channels. (C) 2011 Elsevier B.V. All rights reserved.
Managerial efficiency in Taiwan bank branches: A network DEA
(2012-03-01)
Yang, Chyan
;
Liu, Hsian-Ming
;
經營管理研究所
;
Institute of Business and Management
Taiwan's banking industry remains highly fragmented and competitive after a series of financial liberalization and restructuring. With the enforcement of these fiscal policies, domestic banking institutions face a more dynamic, increasingly intense and highly competitive environment even as the banking industry's overall efficiency has gradually been enhanced. This structural change has further forced individual banking institutions, especially state-owned banks, to inspect the performance of their branches and identify improvement directions so as to gain further competitive advantages. To conduct a valid, fair and reliable evaluation on Taiwan's bank branches, we integrate a two-stage series performance model and fuzzy multiobjective model. A new scheme that considers the complementation of production and intermediation activities within a branch and overcomes the shortage of the traditional network DEA methodology about DMUs cannot be assessed on a common base. The results indicate that the overall performances of mixed ownership bank branches are superior to those of state-owned bank branches, representing that the advantages of banking privatization have some remedial effects for improving the managerial inefficiency of state-owned banks. In addition, the sensitivity analysis and decision-making matrix herein help bank management to identify branches' efficiency, weakness, and directions for improvement. (C) 2011 Elsevier B.V. All rights reserved.
Theory of infrared-dressed atomic photoionization by extremely ultraviolet attosecond pulse trains
(2012-03-01)
Lee, Han Chieh
;
Da Jheng, Shih
;
Jiang, Tsin Fu
;
物理研究所
;
Institute of Physics
We theoretically study the infrared (IR)-dressed photoionization of atoms excited by extreme ultraviolet attosecond pulse trains above ionization threshold. The initial state of atoms is treated perturbatively by the IR field, and the continuum states are considered as Coulomb-Volkov (CV) waves. CV waves can much reduce the gauge difference calculated with Volkov waves, and, in general, the contribution of ground-state perturbation to the photoelectron spectrum is negligible. Our calculations show qualitative agreement with the experimental results [Phys. Rev. Lett. 95, 013001 (2005)]. An evident dependence of the photoelectron spectrum on the delay phase between the IR field and the attosecond pulse train is exhibited in both helium and argon. The angular distribution of photoelectrons with various IR polarizations and the corresponding photoelectron spectra are presented. The linearly polarized IR fields are shown to have a higher controlling capability of the spectrum via IR delay phases than the circularly polarized fields. On the other hand, the circularly polarized IR fields have a fruitful angular dependence of photoelectrons with various IR delay phases. (C) 2012 Optical Society of America
NCTU-VT: a freeware for wireless VoIP performance measurement
(2012-03-01)
Sung, Ya-Chin
;
Lin, Yi-Bing
;
Liou, Ren-Huang
;
Shieh, Lon-Fon
;
資訊工程學系
Voice over IP (VoIP) is a promising low-cost voice communication over the wireless IP network. To provide satisfactory VoIP services, the Quality of Service (QoS) of the wireless network should be guaranteed. This paper proposes a VoIP performance measurement freeware called NCTU VoIP Testing Tool (NCTU-VT). We compare NCTU-VT with two commercial tools SmartVoIPQoS and IxChariot in terms of packet loss, latency, and Mean Opinion Score (MOS) of the VoIP sessions in Wi-Fi network. Our study indicates that these three tools can accurately measure VoIP performance in Wi-Fi environment. Copyright (c) 2010 John Wiley & Sons, Ltd.
Balanced Resource Scheduling Scheme With Adaptive Priority Thresholds for OFDMA Downlink Systems
(2012-03-01)
Chung, Yao-Hsing
;
Chang, Chung-Ju
;
電機工程學系
;
Department of Electrical and Computer Engineering
This paper proposes a new balanced resource scheduling (BRS) scheme with adaptive priority thresholds for orthogonal frequency-division multiple-access (OFDMA) downlink systems. The BRS scheme achieves an excellent balance between quality-of-service (QoS) requirement guarantee and system throughput enhancement, whereas conventional schemes cannot explicitly and accurately control this tradeoff. Based on the adaptive priority threshold of each user, the BRS scheme first performs a priority-based resource allocation (RA) algorithm for users whose priority value is larger than its priority threshold to fulfill the QoS requirement. The BRS scheme then performs a channel-state-information (CSI)-based RA algorithm for the remaining users to enhance system throughput. To achieve balance between QoS guarantee and throughput enhancement, a fuzzy inference priority threshold generator adaptively and intelligently adjusts the priority threshold of each user. Simulation results show that the proposed BRS scheme with adaptive priority threshold enhances the system throughput by 16%, 8.5%, 8.2%, and 46.8% at traffic load of 0.93, compared with conventional adaptive radio RA (RRA), utility-based RRA, utility-based throughput maximization and complexity reduction scheduling, and fairness and QoS guarantee scheduling with fuzzy controls schemes, respectively, under a QoS requirement guarantee. This approach also outperforms the BRS scheme with fixed priority thresholds in both throughput enhancement and QoS guarantee.
Concise Synthesis of Yashabushidiol A and (+/-)-Diospongin A
(2012-03-01)
Ho, Tse-Lok
;
Tang, Bin
;
Ma, Guohua
;
Xu, Pengfei
;
應用化學系
Synthesis of (+/-)-diospongin A has been achieved from the (2SR,4RS)-pentane-1,2,4,5-tetraol in six steps. An intermediate has also been converted into yashabushidiol A. This work features a desymmetric cyclization and reduction of a meso-1,7-diarylheptanoid precursor to furnish the desired cis-2,6-disubstituted tetrahydropyran.
具有脈衝噴氣清洗放電電極線的濕式靜電集塵器
(2012-03-01)
蔡春進
;
林冠宇
一種具有脈衝噴氣用以清潔放電電極線的濕式靜電集塵器，包含有一外殼、三放電電極線、二表面粗糙且塗敷TiO2或SiO2奈米微粒的收集電極、二多孔金屬板以及二粗糙且塗敷TiO2或SiO2奈米微粒之玻璃平板；多孔金屬板以及玻璃平板位於該收集電極之頂側，用以提高流經收集電極水膜之均勻度，當微粒被導入濕式靜電集塵器內部時，微粒可藉由電場以及擴散充電機制而帶電，並在靜電力之作用下朝收集電極移動，隨後被水膜沖洗去除，另外，經由收集電極板上之通氣小孔而噴出之脈衝噴氣更可清除放電電極線表面累積之微粒，而可避免電暈強度之降低並提高使用壽命。
Drawing Social Networks Using Area-Labeling Rectangular Cartograms
(2012-03-01)
Lin, We Dar
;
Jhong, Shun-Yu
;
Huang, Weidong
;
Lin, Chun-Cheng
;
工業工程與管理學系
People are linked together by social networks, whose complexity depends upon a lot of factors. To our understanding, most visualization interfaces for social networks have not been designed for reflecting their factors so far. As a result, this paper tries to solve such a problem by rectangular cartogram, which is a kind of geographical visualization interface using rectangles to represent regions in a map. Besides the relative position of each rectangle can reflect actual geographical related positions, one of the main features of rectangular cartograms is to use the area size or the shape of each rectangle to reflect the information of its corresponding region, e.g., the population in that region. This paper proposes a layout approach for rectangular cartograms with area labeling for social networks, in which each region has a minimum-width constraint for accommodating a text label. To satisfy the practical use for social networks, we apply a genetic algorithm to finding the minimum-width area-labeling rectangular cartogram under some constraints. By doing so, we can visualize the labeling text on each rectangle and observe the information represented by its area size or shape at the same time. Furthermore, the proposed approach is applied to visualizing the distribution of the Facebook popularity of an enterprise in Taiwan. From the cartogram, the text label on each region can be read directly and the relation among regions as well as their popularity can be visualized at the same time, so that the enterprise can improve the regions with poor popularity by the help from the regions with high popularity.
Freeway drivers' willingness-to-pay for a distance-based toll rate
(2012-03-01)
Jou, Rong-Chang
;
Chiou, Yu-Chiun
;
Chen, Ke-Hong
;
Tan, Hao-I
;
運輸與物流管理系註：原交通所+運管所
This paper applies the contingent valuation method to investigate and estimate the toll rate that freeway drivers are willing-to-pay (WTP) for each unit of distance they travel, after switching from per-entry based to distance-based tolling system. Due to a large portion of respondents who are unwilling to pay a toll at all, we adopt the spike model to avoid estimation errors. The estimation results show that average willingness to pay toll is TWD1 0.86/km, which can be refined further to TWD 0.81/km for short distance travelers. TWD 0.93/km for medium distance travelers, and TWD 0.97/km for long distance travelers. Additionally, the WTP toll rate of short distance travelers is significantly different on public holidays but not during peak hours. In contrast, the WTP toll rates of medium and long distance travelers significantly different during peak hours but not on public holidays. (C) 2011 Elsevier Ltd. All rights reserved.
Latent class nested logit model for analyzing high-speed rail access mode choice
(2012-03-01)
Wen, Chieh-Hua
;
Wang, Wei-Chung
;
Fu, Chiang
;
運輸與物流管理系註：原交通所+運管所
;
Department of Transportation and Logistics Management
This paper explores access mode choice behavior, using a survey data collected in Taiwan. The latent class nested logit model is used to capture flexible substitution patterns among alternatives and preference heterogeneity across individuals while simultaneously identifying the number, sizes, and characteristics of market segments. The results indicate that a four-segment latent class nested logit model with individual characteristics in segment membership functions is the most preferred specification. Most high-speed rail travelers were cost-sensitive to access modes, and thus strategies that reduce the access costs can be more effective than reducing the access times. (C) 2011 Elsevier Ltd. All rights reserved.
Study on the Reaction of CH2 with H-2 at High Temperature
(2012-03-01)
Lee, Pei-Fang
;
Matsui, Hiroyuki
;
Wang, Niann-Shiah
;
應用化學系
;
Department of Applied Chemistry
Thermal decomposition of CH2I2 [sequential C-I bond fission processes, CH2I2 + Ar -> CH2I + I + Ar (1a) and CH2I + Ar -> (CH2)-C-3 + I + Ar (1b)], and the reactions of (CH2)-C-3 + H-2 -> CH3 H (2) and (CH2)-C-1 + H-2 -> CH3 + H (3) have been studied by using atomic resonance absorption spectrometry (ARAS) of I and H atoms behind reflected shock waves. Highly diluted CH2I2 (0.1-0.4 ppm) with/without excess H-2 (300 ppm) in Ar has been used so that the effect of the secondary reactions can be minimized. From the quantitative measurement of I atoms in the 0.1 ppm CH2I2 + Ar mixture over 1550-2010 K, it is confirmed that two-step sequential C-I bond fission processes of CH2I2, (la) and (1b), dominate over other product channels. The decomposition step (1b) is confirmed to be the rate determining process to produce 3CH2 and the least-squares analysis of the measured rate gives, In(k(1b)/cm(3) molecule(-1) s(-1)) = -(17.28 +/- 0.79) - (30.17 +/- 1.40) x 10(3)/T. By utilizing this result, we examine reactions 2 and 3 by monitoring evolution of H atoms in the 0.2-0.4 ppm CH2I2 + 300 ppm H2 mixtures over 18502040 K. By using a theoretical result on k(2) (Lu, K. W.; Matsui, H.; Huang, C.-L.; Raghunath, P.; Wang, N.-S.; Lin, M. C. J. Phys. Chem. A 2010, 114, 5493), we determine the rate for (3) as k(3)/cm(3) molecule(-1) s(-1) = (1.27 +/- 0.36) x 10(-10). The upper limit of k(3) (k(3max)) is also evaluated by assuming k(2) = 0, i.e., k(3max)/cm(3) molecule(-1) s(-1) = (2.26 +/- 0.59) x 10(-10). The present experimental results on k(3) and k(3max) is found to agree very well with the previous frequency modulation spectroscopy study (Friedrichs, G.; Wagner, H. G. Z. Phys. Chem. 2001, 215, 1601); i.e., the importance of the contribution of (CH2)-C-1 in the reaction of CH2 with H-2 at elevated temperature range is reconfirmed.
ANALYTICAL METHOD FOR ACCURACY ANALYSIS OF THE RANDOMIZED T-POLICY QUEUE
(2012-03-01)
Wang, Kuo-Hsiung
;
Yang, Dong-Yuh
;
Pearn, W. L.
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
We consider a randomized policy to control the M/G/1 queueing system with an unreliable server, second optional service and general startup times. The server is subject to breaking down according to a Poisson process, and the repair time obeys a general distribution. All arrived customers demand the first required service, and only some of the arrived customers demand the second optional service. After all the customers are served in the system, the server immediately takes a vacation and operates the (T, p)-policy. For this queueing system, we employ maximum entropy approach with several constraints to develop the probability distributions of the system size and the expected waiting time in the queue. Based on the accuracy comparison between the exact and approximate methods, we show that the maximum entropy approach is quite accurate for practical purpose, which is a useful method for solving complex queueing systems.
Vacuum-free lamination of low work function cathode for efficient solution-processed organic light-emitting diodes
(2012-03-01)
Chang, Yu-Fan
;
Chen, Chun-Yu
;
Luo, Fang-Tsai
;
Chao, Yu-Chiang
;
Meng, Hsin-Fei
The low work function cathode of blade-coated organic light-emitting diode is transferred from a soft polydimethylsiloxane (PDMS) mold by lamination without vacuum. The cathode is a bilayer of polyethylene glycol (PEG) (< 10 nm) and Al (100 nm). A sacrificial layer of polystyrene with low Mw 1500 and melting point of 120 degrees C is inserted between the cathode and PDMS for the subsequent mold removal at 150 degrees C by melting polystyrene. Current efficiency of 3 cd/A (1.1%) and luminance of 2500 cd/m(2) are achieved for green polyfluorene fluorescent emitter. 25 cd/A (8.2%) and 3200 cd/m(2) are achieved for green phosphorescent tris[2-(p-tolyl) pyridine] iridium(III) (Ir(mppy)(3)) emitter in polymer blend host. The efficiency is about 70% of the devices with thermally evaporated cathode. The turn-on voltage is about 5 V higher. (C) 2011 Elsevier B. V. All rights reserved.
EMPOWER MCDM BY HABITUAL DOMAINS TO SOLVE CHALLENGING PROBLEMS IN CHANGEABLE SPACES
(2012-03-01)
Chen, Yen-Chu
;
Huang, Hung-Shun
;
Yu, Po-Lung
;
資訊管理與財務金融系註：原資管所+財金所
;
Department of Information Management and Finance
Challenging decision problems in changeable spaces are characterized by existence of complex decision parameters that are changing with time and situations, including criteria and alternatives. Some of these parameters may be critical for their effective solutions, but hidden in the depth of potential domains. In this rapidly changing world, including technology and attitude, without paying attention to the problems in changeable spaces, we could easily commit serious mistakes due to decision blinds, decision traps and/or decision shocks. The article starts with a brief description of the evolution of MCDM toward challenging problems in changeable spaces. Then it briefly sketches a dynamic human behavior mechanism and habitual domain theory which provide an effective list for us to search relevant decision parameters and pave the way for latter discussion. Competence set analysis, derived from habitual domain, is then introduced to exemplify decision blinds, decision traps and decision shocks in challenging decision problems. Checking lists and methods for discovering blinds and traps and for dealing with shocks are also provided. Innovation dynamics, a systematic network of thoughts, is introduced to further look out relevant key parameters in dynamic challenging problems. The related academic subjects in each link of the innovation dynamics are also explained, which allow us to see the complexity and interconnectivities among different challenging problems in changeable spaces. Finally we introduce three habitual domain tool boxes to empower ourselves to expand and enrich our thoughts into the depth of the potential domains of the challenging problems, which allows us to more effectively identify hidden parameters, problems and competence sets to reduce decision blinds, avoid decision traps and solve the problems, or dissolve the problems before they occur.