Browsing by Issue Date, starting with "2007-09-01"

Now showing 1 - 20 of 59223

Evaluating the supply chain performance of IT-based inter-enterprise collaboration
(2007-09-01)
Chen, Mu-Chen
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Yang, Taho
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Li, Hsin-Chia
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運輸與物流管理系註：原交通所+運管所
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Department of Transportation and Logistics Management
With the use of IT, the nature of business processes has changed from intra- to cross-enterprise. This has significantly altered enterprise interactions with suppliers and customers. Collaboration is essential for successful supply chain performance. In recent years a variety of initiatives have been adopted by industries. These attempted to create efficiency and effectiveness through integration of the activities and processes. However, enterprises can only gain significant benefits by mass collaboration. Collaborative Planning, Forecasting and Replenishment (CPFR), which result in deeper partnerships, have become an important factor in supply chains. We investigated the performance of CPFR; it possesses formalized guidelines and is a relatively new initiative. By using simulation, we investigated four CPFR alternatives that are used in the adoption of collaboration strategies in industries. Retailers have traditionally played the hub role in supply chains in order to reduce the bullwhip effect, but our simulation confirmed that shifting the retailer (buyer-driven) collaboration to a manufacturer (supplier-driven) approach was a more viable option. (C) 2007 Elsevier B.V. All rights reserved.
Entanglement detection via the condition of quantum correlation
(2007-09-01)
Li, Che-Ming
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Hsu, Li-Yi
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Chen, Yueh-Nan
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Chuu, Der-San
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Brandes, Tobias
We develop a necessary condition of quantum correlation. It is utilized to construct a d-level bipartite Bell-type inequality which is strongly resistant to noise and requires only analyses of O(d) measurement outcomes compared to the previous result O(d(2)). Remarkably, a connection between the arbitrary high-dimensional bipartite Bell-type inequality and entanglement witnesses is found. Through the necessary condition of quantum correlation, we propose that the witness operators to detect truly multipartite entanglement for a generalized Greenberger-Horne-Zeilinger (GHZ) state with two local measurement settings and a four-qubit singlet state with three settings. Moreover, we also propose a robust entanglement witness to detect a four-level tripartite GHZ state with only two local measurement settings.
Interaction of AC magnetic field with Josephson vortices in high anisotropy superconductors Bi2212 and Bi2223
(2007-09-01)
Shaltiel, D.
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von Nidda, H.-A. Krug
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Shapiro, B. Ya.
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Shapiro, I.
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Loidl, A.
We show that in both high anisotropy superconductors Bi2212 (T-c = 90 K), and Bi2223 (T-c = 110 K), an AC magnetic field applied collinear to the DC field and parallel to the Cu layers induces strong microwave dissipation. It is theoretically predicted that the Josephson solitons are responsible for this absorption. Good qualitative agreement of experimental data with theoretical predictions is found. Differences observed in the experimental results between these two compounds are discussed. (c) 2007 Elsevier B.V. All rights reserved.
An innovative understanding of metal-insulator-metal (MIM)-capacitor degradation under constant-current stress
(2007-09-01)
Hung, Chi-Chao
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Oates, Anthony S.
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Lin, Horng-Chih
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Chang, Yu-En Percy
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Wang, Jia-Lian
This paper provides a new understanding of metal-insulator-metal-capacitor-degradation behavior under a wide range of constant-current-stress conditions. It was found that capacitance degrades with stress, but the behavior of the degradation strongly depends on the stress-current density. At high stress levels, the capacitance increases logarithmically as the injection charge increases until dielectric breakdown occurs. At lower stress conditions, the degradation rate is proportional to the stress current and reverses after a certain period of time. A metal-insulator interlayer is observed using cross-sectional transmission-electron-microscopy micrographs, which possibly explains this reversal phenomenon.
A cross-layer investigation for the throughput performance of CSMA/CA-Based WLANs with directional antennas and capture effect
(2007-09-01)
Wang, Li-Chun
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Chen, Anderson
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Huang, Shi-Yen
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電信工程研究所
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Institute of Communications Engineering
In this paper, we develop a physical/medium-access-control (PHY/MAC) cross-layer analytical model to investigate the throughput performance of the wireless local-area network (WLAN) in a lossy wireless environment. From the PHY-layer perspective, the developed model incorporates the effects of capture and directional antennas, while from the MAC-layer perspective, our approach takes into account the carrier-sense multiple access with collision-avoidance (CSMA/CA) MAC protocol and the effect of the backoff process in the IEEE 802.11 WLAN. We derive explicit analytical expressions for the frame outage and capture probabilities of a directional antenna system in the presence of shadowing and Rayleigh fading. Applying this analysis, we can model the interaction between the PHY and MAC layers more accurately for the infrastructure-based WLAN. The numerical results show that our analytical model can approach that attained by simulations. The proposed cross-layer analytical model not only provides insights into the PHY layer impacts on the throughput of the CSMA/CA MAC protocol but also indicates to how directional antennas can improve the CSMA/CA-based WLAN in terms of antenna beamwidth and the number of radio transceivers.
Specific heat of Mn-doped NaxCoO2 center dot yH(2)O
(2007-09-01)
Lin, J.-Y.
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Chen, Y.-J.
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Liu, C.-J.
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Wang, J.-S.
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Sun, C. P.
C(T) of NaxCo0.99Mn0.01O2 center dot yH(2)O is studied to reveal more details on the nature of the doped Mn ions and the T-c suppression. The extra specific heat contribution in NaxCo0.99Mn0.01O2 center dot yH(2)O manifests the induced local magnetic moment due to Mn doping. The absence of the superconducting transition peak in C(T) of NaxCo0.99Mn0.01O2 center dot yH(2)O suggests a reduced superconducting volume fraction. (C) 2007 Elsevier B.V. All rights reserved.
Study of the gate-sensing and channel-sensing transient analysis method for monitoring the charge vertical location of SONOS-type devices
(2007-09-01)
Du, Pei-Ying
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Lue, Hang-Ting
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Wang, Szu-Yu
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Lai, Erh-Kun
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Huang, Tiao-Yuan
The gate-sensing and channel-sensing transient analysis method is studied in detail. This method introduces an additional gate-sensing capacitor to be compared with the conventional channel-sensing one. Sensing in both modes provides two equations that are suitable to solve for two variables-the charge density (Q) and the average charge vertical location (x). In this paper, the principle of this method is discussed in detail. Several factors that affect the measurement accuracy are also analyzed. The power of this method is demonstrated by program/erase cycling and data retention tests. This method is indeed a powerful tool for detailed understanding of trapping dynamics.
Efficient support for content-aware request distribution and persistent connection in Web clusters
(2007-09-01)
Liu, Ho-Han
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Chiang, Mei-Ling
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Wu, Men-Chao
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資訊工程學系
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Department of Computer Science
To support Web clusters with efficient dispatching mechanisms and policies, we propose a light-weight TCP connection transfer mechanism, TCP Rebuilding, and use it to develop a content-aware request dispatching platform, LVS-CAD, in which the request dispatcher can extract and analyze the content in requests and then dispatch each request by its content or type of service requested. To efficiently support HTTP/1.1 persistent connection in Web clusters, request scheduling should be performed per request rather than per connection. Consequently, multiple TCP Rebuilding, as an extension to normal TCP Rebuilding, is proposed and implemented. On this platform, we also devise fast TCP module handshaking to process the handshaking between clients and the request dispatcher in the IP layer instead of in the TCP layer for faster response times. Furthermore, we also propose content-aware request distribution policies that consider cache locality and various types of costs for dispatching requests in this platform, which makes the resource utilization of Web servers more effective. Experimental results of a practical implementation on Linux show that the proposed system, mechanisms, and policies can effectively improve the performance of Web clusters. Copyright (C) 2007 John Wiley & Sons, Ltd.
Dynamics of disordered type-II superconductors: Peak effect and the I-V curves
(2007-09-01)
Bel, G.
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Li, D. P.
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Rosenstein, B.
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Vinokur, V.
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Zhuravlev, V.
We quantitatively describe the competition between the thermal fluctuations and disorder by the Ginzburg-Landau approach using both the replica method in statics and the dynamical Martin-Siggia-Rose approach which allows generalization beyond linear response. The two methods are consistent in static, while the dynamical method allows calculation of the critical current as function of magnetic field and temperature. The surface in the J-B-T space defined by this function separates between a dissipative moving vortex matter regime and vortex glass. The non-Ohmic I-V curve is obtained. (c) 2007 Elsevier B.V. All rights reserved.
Optimal design of resonant piezoelectric buzzer from a perspective of vibration-absorber theory
(2007-09-01)
Bai, Mingsian R.
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Chen, Rong-Liang
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Chuang, Chung-Yuan
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Yu, Cheng-Sheng
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Hsieh, Huey-Lin
In this paper, an optimization technique is presented for the design of piezoelectric buzzers. This design technique aims at finding the optimal configuration of the coupled cavity and diaphragm structure to maximize the sound pressure output. Instead of measuring the material constants of the piezoelectric ceramic and the metal diaphragm, an "added-mass method" is developed to estimate the equivalent electromechanical parameters of the system on which an analogous circuit can be established. The electrical impedance and on-axis sound pressure level of the piezoelectric buzzer can be simulated by solving the loop equations of the electromechanoacoustical analogous circuit. An interesting finding of this research is that the nature of the piezoelectric buzzer bears remarkable resemblance to that in the dynamic vibration absorber theory. Much physical insight can be gained by exploiting this resemblance in search of the optimal configuration. According to the system characteristic equation, a design chart was devised to "lock" the critical frequency at which the system delivers the maximal output. On the basis of the analogous circuit and the vibration absorber theory, an optimal design was found with constrained optimization formalism. Experiments were conducted to justify the optimal design. The results showed that the performance was significantly improved using the optimal design over the original design. Design guidelines for the piezoelectric buzzers are summarized. (c) 2007 Acoustical Society of America.
The nanocomposite thin film applied to high-density write-once optical data storage
(2007-09-01)
Mai, Hung-Chuan
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Hsieh, Tsung-Eong
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材料科學與工程學系
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Department of Materials Science and Engineering
This work demonstrates the feasibility of producing composite thin films containing nano-scale recording particles for highdensity optical data storage. The nanocomposite recording layers were found to exhibit an ultrafast transition rate and a unique phase transition temperature compared with the bilayer recording systems. For type I disk samples containing a nanocomposite recording layer and a Ag reflection layer, modulations higher than 0.8 and 0.5 could be achieved when I IT and 4T signals were respectively written into the disk samples using a blue-laser dynamic tester. As for type 11 disk samples containing a sole nanocomposite recording layer, modulations better than 0.8 and 0.6 were obtained. Transmission electron microscopy (TEM) characterization attributed the main signal recording mechanism to the coalescence and coarsening of nano-recording particles, which, in turn, implies a sufficient reflectivity difference for signal readout. The reactions and/or redistribution of elements involved in the layer structure of optical disks also contributed to the signal recording. The nanocomposite recording layer provides various advantages including a fast phase transition rate, initialization-free, disk structure simplification, and a sputtering-compatible fabrication process and thus, promising applications to next-generation write-once optical data storage are expected.
High-power single-mode submonolayer quantum-dot photonic crystal vertical-cavity surface-emitting lasers
(2007-09-01)
Lai, Fang-I.
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Yang, H. P. D.
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Lin, G.
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Hsu, I. -Chen
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Liu, Jui-Nung
A high-power, wide operation-range single-fundamental-mode InGaAs submonolayer (SML) quantum dot (QD) photonic crystal vertical-cavity surface-emitting laser (VCSEL) for fiber-optic applications was demonstrated. Single-fundamental-mode with a threshold current (I-th) of 0.9 mA and maximum continue-wave (CW) output power of 3.8 mW at 28 mA has been achieved in the 990 nm range. A side-mode suppression ratio (SMSR) larger than 35 dB has been observed over the entire current operating range. The far field measurement shows that the beam divergence angle remains very small and almost unchanged between 6.7-6.9 degrees, with the operation range increasing from 3 to 20 mA.
The effects of group composition of self-efficacy and collective efficacy on computer-supported collaborative learning
(2007-09-01)
Wang, Shu-Ling
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Lin, Sunny S. J.
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教育研究所
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Institute of Education
Although research has suggested that group composition plays an important role in collaborative learning, the role of motivation in group composition has rarely been taken into account. This study investigates the effects of group composition of self-efficacy (e.g. low, high, and mixed self-efficacy) on group motivation (i.e. collective efficacy), collaborative learning behavior, and performance in a computer-supported collaborative learning environment. The results indicate that high self-efficacy groups have higher collective efficacy beliefs than low self-efficacy groups. Furthermore, high self-efficacy groups use more high-level cognitive skills during group discussion than low self-efficacy groups, despite no significant difference in usage of lowlevel cognitive skills among the three groups. This study also demonstrates that collective efficacy has positive effects on discussion behaviors and group performance. Students with higher collective efficacy not only use more high-level cognitive skills in group discussion, but also demonstrate better academic performance. Our research further indicates that students' use of high-level cognitive skills in group discussion has positive effects on group performance. Finally, implications and suggestions for future research are also provided. (c) 2006 Elsevier Ltd. All rights reserved.
Immunochemical property of human haptoglobin phenotypes: Determination of plasma haptoglobin using type-matched standards
(2007-09-01)
Cheng, Tsai-Mu
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Pan, Ju-Pin
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Lai, Shiau-Ting
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Kao, Li-Pin
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Lin, Hong-Huel
Objectives: Haptoglobin (Hp) phenotypes 1-1, 2-1, and 2-2 are associated with inflammatory diseases. Since their biochemical structures are rather heterogeneous, it is necessary to accurately determine the plasma Hp levels. Design and methods: Immunodiffusion, immunoturbidimetric, and noncompetitive ELISA were conducted to determine the differences in immunoreactivity among Hp phenotypes and to verify that such difference may significantly affect the outcome of Hp determinations. A novel ELISA using phenotype-matched calibrators was performed to compared with a commercial GenWay ELISA kit using a single calibrator in normal healthy males. Results: In immunodiffusion and immunoturbidimetric assays, the immumoreactivity of Hp 1-1 was markedly higher than 2-1 and 2-2, while an opposite result was observed using an ELISA. The latter was primarily due to the repeated antigenic epitopes in polymeric 2-1 and 2-2. Thus, Hp levels could be significantly over- or underestimated depending on the method. An accurate ELISA could be achieved when using each type-specific Hp calibrator matched to each type subject. We show the mean levels of Hp 1-1 subjects (n= 16; 184 +/- 42 mg/dL) to be significantly and differentially greater than 2-1 (n=28; 153 +/- 55 mg/dL) (p < 0.05) and 2-2 (n=24; 93 +/- 54 mg/dL) (p < 0.01) subjects. Conclusions: Due to the diverse immunochemical structure among the Hp types, phenotyping should be performed in all the patients and a type-matched Hp calibrator should be used in clinical Hp determination. (c) 2007 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.
Robust control design for perturbed systems by frequency domain approach
(2007-09-01)
Wu, Bing-Fei
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Chin, Hung-I
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Perng, Jau-Woei
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Lee, Tsu-Tian
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電控工程研究所
This paper is concentrated on a perturbed vehicle control system whose gain margin (GM) and phase margin (PM) are analyzed and for which a novel controller design method satisfying the given specifications on GM, PM, and sensitivity is developed. The approach is applied to the plants with uncertain parameters that vary in intervals. Based on the parameter space method and robust stability criteria, gain and phase boundary curves are generated from the characteristic polynomial of the system with which a gain-phase tester is included in series to perform system stability analysis and controller design. The main concern in the controller design is to find a region in the controller coefficient plane so that the performance of the uncertain system satisfies given specifications. The proposed method is applied to an example of a bus system. Simulation results are given for illustration to show the system performances on GM and PM, and the desired controller meeting the specified conditions in frequency domain for the perturbed system is derived.
「新店渡」誰
(2007-09-01)
管管
A novel nanowire channel poly-Si TFT functioning as transistor and nonvolatile SONOS memory
(2007-09-01)
Chen, Shih-Ching
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Chang, Ting-Chang
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Liu, Po-Tsun
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Wu, Yung-Chun
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Lin, Po-Shun
In this letter, a polycrystalline silicon thin-film transistor consisting of silicon-oxide-nitride-oxide-silicon (SONOS) stack gate dielectric and nanowire (NW) channels was investigated for the applications of transistor and nonvolatile memory. The proposed device, which is named as NW SONOS-TFT, has superior electrical characteristics of transistor, including a higher drain current, a smaller threshold voltage (V-th), and a steeper subthreshold slope. Moreover, the NW SONOS-TFT also can exhibit high program/erase efficiency under adequate bias operation. The duality of both transistor and memory device for the NW SONOS-TFT can be attributed to the trigate structure and channel corner effect.
Characterization of inductor with Ni-Zn-Cu ferrite embedded in B2O3-SiO2 glass
(2007-09-01)
Jao, Jui-Chu
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Li, Pang
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Wang, Sea-Fue
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材料科學與工程學系
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Department of Materials Science and Engineering
In this study, inductors using a new low-temperature cofirable ceramic (LTCC) design, in which Ni-Zn-Cu ferrite was buried in B2O3-SiO2 glass within the core of the spiral silver coil, were fabricated. The inductance and quality factor of the inductor with embedded ferrite are larger than those of pure B2O3-SiO2 glass. Ni-Zn-Cu ferrite was incompatible with the B2O3-SiO2 glass during the cofiring process due to sintering shrinkage mismatch. The incompatibility was resolved when 35 wt % Al2O3 was doped into the B2O3-SiO2 glass, which produces a glass-ceramic, and 2 wt % of Bi2O3 was fluxed into the Ni-Zn-Cu ferrite as a sintering aid. The addition of 2 wt % of Bi2O3 not only enhances densification, but also increases the permeability of Ni-Zn-Cu ferrite.
System parameters evaluation of flexibly supported laminated composite sandwich plates
(2007-09-01)
Lee, C. R.
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Sun, S. J.
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Kam, T. Y.
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機械工程學系
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Department of Mechanical Engineering
A nondestructive evaluation technique established on the basis of a global minimization method is presented for the system parameters identification of flexibly supported rectangular laminated composite sandwich plates using measured natural frequencies of the sandwich plates. In this study, the first eight natural frequencies extracted from impulsive vibration testing data are used to identify the system parameters of the flexibly supported sandwich plates. In the identification process, the trial system parameters are used in the Rayleigh-Ritz method to predict the theoretical natural frequencies of the sandwich plate, a frequency discrepancy function is established to measure the sum of the squared differences between the experimental and theoretical predictions of the natural frequencies, and the global minimization method is used to search for the best estimates of the system parameters by making the frequency discrepancy function a global minimum. The accuracy and efficiency of the proposed technique in identifying the system parameters of several flexibly supported sandwich plates made of different face and core materials are studied via both theoretical and experimental approaches. The reasonably good results obtained in this study have demonstrated the applicability of the proposed technique.
Nanometer-sized diamond particle as a probe for biolabeling
(2007-09-01)
Chao, Jui-I.
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Perevedentseva, Elena
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Chung, Pei-Hua
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Liu, Kuang-Kai
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Cheng, Chih-Yuan
A novel method is proposed using nanometer- sized diamond particles as detection probes for biolabeling. The advantages of nanodiamond's unique properties were demonstrated in its biocompatibility, nontoxicity, easily detected Raman signal, and intrinsic fluorescence from its natural defects without complicated pretreatments. Carboxylated nanodiamond's ( cND's) penetration ability, noncytotoxicity, and visualization of cND- cell interactions are demonstrated on A549 human lung epithelial cells. Protein- targeted cell interaction visualization was demonstrated with cND- lysozyme complex interaction with bacteria Escherichia coli. It is shown that the developed biomolecule- cND complex preserves the original functions of the test protein. The easily detected natural fluorescent and Raman intrinsic signals, penetration ability, and low cytotoxicity of cNDs render them promising agents in multiple medical applications.