Browsing by Issue Date, starting with "2010-05-01"

Now showing 1 - 20 of 46341

Growth of vertically aligned ZnO nanorod arrays as antireflection layer on silicon solar cells
(2010-05-01)
Chen, J. Y.
;
Sun, K. W.
;
應用化學系
;
Department of Applied Chemistry
In this work we investigated the effects of growth time, spin-coating rates, and solution concentration on the reflection properties of the solution-grown ZnO nanorod arrays. The vertically aligned nanorod arrays were deposited on the surface of the Si solar cells as the antireflection (AR) layer. We found that the nanorod morphology, controlled through synthetic chemistry, has a great effect on the AR layer performance. We also demonstrated that the light harvest efficiency of the solar cells was greatly improved from 10.4% to 12.8% by using the vertically aligned ZnO nanorod arrays as the AR layer on poly-Si solar cells. (C) 2010 Elsevier B.V. All rights reserved.
Cooperative Sensing of Wideband Cognitive Radio: A Multiple-Hypothesis-Testing Approach
(2010-05-01)
Wu, Sau-Hsuan
;
Yang, Chao-Yuan
;
Huang, D. -H. Tina
;
電信工程研究所
;
Institute of Communications Engineering
A low-complexity decision fusion method is proposed for cooperative spectrum sensing (SS) of wideband cognitive radio (CR) using multiple-hypothesis testing. To maintain the quality of SS in multiple channels, performance indices of false-sensing rate and false-ignorance rate are defined for the Benjamini-Hochberg (BH) procedure to control the false-alarm ratio (FAR) and missing ratio (MR) of SS, respectively. Extended from these results, a double BH procedure is further studied in an attempt to simultaneously attain a low FAR and MR. In addition to identifying the availability of channels, a signal strength-estimation scheme that features multiple-hypothesis testing is also proposed to classify the level of the SNR for cooperative SS. Simulation results show that the double BH procedure can suppress both the FAR and the MR at a high SNR while maintaining a considerable FAR in the low-SNR regime. As such, the system can enjoy throughput enhancement by allowing more active cognitive access at a high SNR and still prevent introducing excessive multiple-access interference to the primary users when their SNRs are weak. On the other hand, for SNR classification, simulations also show that the SNR can be classified within one level, plus or minus the true strength with more than a 96% chance. This allows the system to employ more generic protocols such as concurrent transmissions for cognitive access.
道路角度估測系統及其方法
(2010-05-01)
陳宗麟
;
許齡元
一種道路角度估測系統及其方法，其中，該系統包含：一感測模組及一估測計算模組。該感測模組裝設於一移動體上以量測出一組包括一懸掛系統位移量、一側向加速度、一縱向速度及一橫擺角之系統量測參數。而該估測計算模組包括一擴增卡曼濾波器且具有實施一儲存記憶褪去法及一描述移動體動態方程式之功能，並用來接收該組系統量測參數、一組包括一假設傾斜角及一假設坡度角之待估參數，及一組包括一操縱角度、一油門力道值及一煞車力道值之操作參數的輸入，並產生一道路角度資訊。藉此，僅利用較少感測設備達成同時且精確的道路角度變化估測。
兆赫波分束器裝置
(2010-05-01)
趙如蘋
;
潘犀靈
;
林家任
;
林俊賢
本發明揭露一種兆赫波分束器，其用以分束一兆赫波成為多個兆赫波。兆赫波分束器包括液晶相位光柵與電壓控制單元。電壓控制單元耦接液晶相位光柵，且提供一控制電壓來改變液晶相位光柵中的液晶分子的排列，使得兆赫波通過液晶相位光柵而分成多個兆赫波。
The impact of high-frequency characteristics induced by intrinsic parameter fluctuations in nano-MOSFET device and circuit
(2010-05-01)
Han, Ming-Hung
;
Li, Yiming
;
Hwang, Chih-Hong
;
傳播研究所
;
電機工程學系
This work estimates the influences of the intrinsic parameter fluctuations consisting of metal gate work-function fluctuation (WKF), process variation effect (PVE) and random dopant fluctuation (RDF) on 16-nm-gate planar metal-oxide-semiconductor field effect transistors (MOSFETs) and circuits by using an experimentally validated three-dimensional device and coupled device-circuit simulations. The dominance fluctuation source in threshold voltage, gate capacitance, cut-off frequency, high-frequency gain, 3 dB bandwidth, unity-gain bandwidth, power, and the power-added efficiency has been found. Similar to the trend of the cut-off frequency, the PVE and RDF dominate both the device and circuits characteristic fluctuations due to the significant gate capacitance fluctuations and the WKF is less important at this simulation scenario. (C) 2010 Elsevier Ltd. All rights reserved.
A NOVEL METHOD FOR HORIZONTAL EYE LINE DETECTION UNDER VARIOUS ENVIRONMENTS
(2010-05-01)
Jing, Min-Quan
;
Cheny, Ling-Hwei
;
資訊工程學系
;
Department of Computer Science
The eye line is defined to be a horizontal line passing the two eyes of a human face. It can be used to help locate the true positions of eyes and face. In this paper, we propose a method to extract the horizontal eye line of a face under various environments. Based on the facts that the eye color is very different from skin color and the gray level variance of an eye is high, some eye-like regions are first located. Then the horizontal eye line is extracted based on the located eye-like regions and some geometric properties in a face. Experimental results are given to show that the proposed method is robust under a wide range of lighting conditions, different poses and races. The detection rate for HHI face database is 95.63%. For Champion face database, the detection rate is 94.27%.
Operation of a Novel Device With Suspended Nanowire Channels
(2010-05-01)
Lin, Horng-Chih
;
Kuo, Chia-Hao
;
Li, Guan-Jang
;
Su, Chun-Jung
;
Huang, Tiao-Yuan
We investigate the operation of a new device featuring a side-gate scheme and suspended poly-Si nanowire (NW) channels. The fabrication adopted a sidewall-spacer-etching technique to form the poly-Si NW channels. The NW channels were further suspended using a simple wet-etching step. An interesting hysteresis phenomenon is observed in the I-V characteristics. In addition, a steep subthreshold swing (< 60 mV/dec) is also observed in the transfer curves. A scenario is proposed to explain the operation of such a device.
A Short Open-End Slot Antenna With Equivalent Circuit Analysis
(2010-05-01)
Wang, Yu-Shin
;
Chung, Shyh-Jong
;
電信工程研究所
;
Institute of Communications Engineering
A novel configuration is described for a compact microstripline fed slot antenna which is shorter than one-eighth wavelength at the operating frequency. Antenna size is reduced by placing two matching capacitors at both sides of an electrically small open-end slot, through the use of a wideband antenna equivalent circuit model established by considering the physical geometry. With the proposed antenna configuration, a 2.45 GHz slot antenna is first designed using an open-end slot of size 9 mm by 1.5 mm that is originally resonant at 4.8 GHz in a conventional design. Experimental results correlate well with those of the full-wave simulation and the equivalent circuit calculation, which shows a bandwidth of 109 MHz and peak gain of 1.89 dBi. By using the same slot size, several slot antennas operating at even lower frequencies (1.9, 1.64, 1.57 GHz) are then designed and demonstrated. Nearly omni-directional radiation patterns with peak gains 0 dBi and radiation efficiencies larger than 45% are obtained. Given its simplicity and compactness, the proposed electrically small antenna is feasible for circuit integration and highly promising for wireless mobile devices.
InGaAs submonolayer quantum-dot photonic-crystal LEDs for fiber-optic communications
(2010-05-01)
Yang, Hung-Pin D.
;
Yeh, Zao-En
;
Lin, Gray
;
Kuo, Hao-Chung
;
Chi, Jim Y.
An InGaAs submonolayer (SML) quantum-dot photonic-crystal light-emitting diode (QD PhC-LED) with for fiber-optic applications is reported. The active region of the device contains three InGaAs SML QD layers. Each of the InGaAs SML QD layers is formed by alternate depositions of InAs (<1 ML) and GaAs. A maximum CW output power of 0.34 mW at 20 mA has been obtained in the 980 nm range. (C) 2010 Elsevier Ltd. All rights reserved.
A class of error-correcting pooling designs over complexes
(2010-05-01)
Huang, Tayuan
;
Wang, Kaishun
;
Weng, Chih-Wen
;
應用數學系
;
Department of Applied Mathematics
As a generalization of d (e) -disjunct matrices and (w,r;d)-cover-free-families, the notion of (s,l) (e) -disjunct matrices is introduced for error-correcting pooling designs over complexes (or set pooling designs). We show that (w,r,d)-cover-free-families form a class of (s,l) (e) -disjunct matrices. Moreover, a decoding algorithm for pooling designs based on (s,l) (e) -disjunct matrices is considered.
A process for high yield and high performance carbon nanotube field effect transistors
(2010-05-01)
Lee, Tseng-Chin
;
Tsui, Bing-Yue
;
Tzeng, Pei-Jer
;
Wang, Ching-Chiun
;
Tsai, Ming-Jinn
Carbon nanotube field effect transistors (CNTFETs) have been considered as one of the potential candidates for nanoelectronics beyond Si CMOS. However, it is not easy to have high performance CNTFETs with high yield currently. In this work, we proposed a local bottom-gate (LBG) CNTFETs combined with a novel device concept and optimized process technologies. High performance of CNTFET with low subthreshold swing of 139 mV/dec, high transconductance of 1.27 mu S, and high I(on)/I(off) ratio of 10(6) can be easily obtained with Ti source/drain contact after a post annealing process. Record high yield of 74% has been demonstrated. On the basis of the proposed process, lots of high performance CNTFETs can be obtained easily for advanced study on the electrical characteristics of CNTFETs in the future. (C) 2010 Elsevier Ltd. All rights reserved.
揚聲器診斷系統及其製作方法
(2010-05-01)
白明憲
;
黃兆民
;
陳榮亮
本發明係關於一個揚聲器診斷系統及其製作方法。揚聲器工作在大訊號的情況下，許多揚聲器的非線性效應便會顯現，非線性效應會造成聲音的失真(distortion)，破壞其音質。本發明之揚聲器診斷系統利用類神經網路架構(neutral fuzzy system)製作專門用於揚聲器缺陷診斷的專家系統，針對不同的失真型態，可以診斷出造成失真的來源並提供改善建議。
A Network-based Simulation Architecture for Studying Epidemic Dynamics
(2010-05-01)
Huang, Chung-Yuan
;
Tsai, Yu-Shiuan
;
Wen, Tzai-Hung
;
資訊工程學系
;
Department of Computer Science
Epidemiology instructors are collaborating with computer scientists to construct network-based simulations to recreate infectious disease transmission dynamics and to examine intervention strategy efficacies. Here we propose an architecture based on demographic and geographic properties to support the learning efforts of undergraduate students and novice researchers, and describe our simulations of HIV, SARS, and influenza transmission dynamics in Taiwan. Our findings are offered to support the construction of new network-based epidemic simulations.
Continuous slip-ring SPECT acquisition with a five-sphere phantom and arbitrary time-frame shifting reconstruction to simulate a dynamic drug challenge study
(2010-05-01)
Kao, Pan-Fu
;
Shiu, Ruei-Lin
;
Lee, Jia-Hung
;
Chou, Yu-Hsiang
;
資訊工程學系
光調變裝置
(2010-05-01)
陳智弘
;
林俊廷
;
江文智
;
彭朋群
;
施伯宗
本發明係揭露一種光調變裝置，包含一電訊號產生器，其係產生一載有資料訊號之一電訊號，另一第一弦波訊號產生器用來產生一第一弦波訊號，輸入光源訊號則由一光訊號產生器產生，光電調變器(Mach-Zehnder modulator)在接收輸入光源訊號、電訊號與第一弦波訊號後，可對光電調變器進行偏壓，以影響輸入光源訊號的傳輸特性，並使該輸入光源訊號經由電訊號與第一弦波訊號調變後，輸出載有電訊號與第一弦波訊號之輸出光源訊號。本發明不但具倍頻功能又可傳輸向量訊號，能進而有效提升頻寬使用效率。
A Power-Efficient Bio-Potential Acquisition Device with DS-MDE Sensors for Long-Term Healthcare Monitoring Applications
(2010-05-01)
Chang, Chia-Lin
;
Chang, Chih-Wei
;
Huang, Hong-Yi
;
Hsu, Chen-Ming
;
Huang, Chia-Hsuan
This work describes a power-efficient bio-potential acquisition device for long-term healthcare applications that is implemented using novel microelectromechanical dry electrodes (MDE) and a low power bio-potential processing chip. Using micromachining technology, an attempt is also made to enhance the sensing reliability and stability by fabricating a diamond-shaped MDE (DS-MDE) that has a satisfactory self-stability capability and superior electric conductivity when attached onto skin without any extra skin tissue injury technology. To acquire differential bio-potentials such as ECG signals, the proposed processing chip fabricated in a standard CMOS process has a high common mode rejection ratio (C. M. R. R.) differential amplifier and a 12-bit analog-to-digital converter (ADC). Use of the proposed system and integrate simple peripheral commercial devices can obtain the ECG signal efficiently without additional skin tissue injury and ensure continuous monitoring more than 70 hours with a 400 mAh battery.
Characterization of a newly synthesized organic nonlinear optical crystal: benzoyl valine
(2010-05-01)
Kumar, T. K.
;
Selvaraj, R. S.
;
Janarthanan, S.
;
Rajan, Y. C.
;
Selvakumar, S.
Herein the synthesis and the crystal growth of benzoyl valine (BV), an organic nonlinear optical (NLO) material for frequency conversion was grown by slow evaporation solution growth technique at room temperature has been reported. The compound was prepared by Stockman method of benzoylation. The solubility curve shows linear nature up to a temperature of 313 K. XRD study reveals that the crystal belongs to monoclinic system with P2(1) non-centrosymmetric space group. The fundamental vibrational frequency of various functional groups (400-4000 cm(-1)) in the crystal was determined from FTIR analysis. (1)H and (13)C NMR spectral studies reveal the presence of proton and carbon network in the grown crystalline sample. The optical behaviour of the crystal was ascertained by optical UV absorption spectral studies. The UV cut off region (gimel(max)) lies around 200 nm and the crystal is absolutely transparent from 220800 nm suggesting its application as NLO material. The thermal stability of the crystal was determined by thermogravimetric and differential thermal analyses. Laser damage threshold of BV was found to be 0.34 GW/cm(2) and hence BV can be used in frequency doubler system. Photoconductivity study of BV revealed negative photoconductiviting nature of the sample. The microhardness studies confirm that BV has a moderate Vickers hardness number (VHN) value in comparison to the other organic NLO crystals.
A QoS Optical Packet Switching System: Architectural Design and Experimental Demonstration
(2010-05-01)
Yuang, Maria C.
;
Lin, Yu-Min
;
Shih, Ju-Lin
;
Tien, Po-Lung
;
Chen, Jason J.
Optical packet switching has been considered a prominent paradigm for future WDM networks to efficiently support a multitude of applications with diverse quality of service requirements. In this article we present the architectural design and experimental demonstration of a 10 Gb/s QoS optical packet switching system (QOPSS) for WDM networks. It embodies a set of many-to-one space switches, each of which handles the switching solely for a cluster of wavelengths. With the cluster-based optical switch design, QOPSS trades off limited statistical multiplexing gains for higher system scalability. By many-to-one, multiple packets that are carried by different internal wavelengths are scheduled to switch to the same output port but receive different delays afterward. QOPSS adopts downsized feed-forward optical buffers, yielding drastic reduction in packet loss probability in an economical manner. Significantly, through using four-wave-mixing wavelength converters at the output section, QOPSS permits optical packet preemption, thus achieving effectual QoS differentiation. The article presents both simulation and experimental testbed results to demonstrate the feasibility and superior packet loss/QoS performance of the system.
適應性音訊控制裝置及其方法
(2010-05-01)
白明憲
;
洪志仁
;
謝秉儒
;
艾學安
本發明揭露一種適應性音訊控制裝置及方法，根據背景噪音的訊號比，對原始訊號提供適當之信號增益，可用於車用音響、通訊產業或視聽娛樂，適應性音訊控制裝置主要結合噪音音量估測裝置、訊號雜訊比裝置、動態範圍控制裝置及一平滑裝置，並結合最小均方演算法，可根據訊號及背景噪音之訊噪比，來調整信號增益，維持穩定之訊噪比，特別適用於車內環境。
Design optimization of scroll compressor applied for frictional losses evaluation
(2010-05-01)
Liu, Yangguang
;
Hung, Chinghua
;
Chang, Yuchoung
;
機械工程學系
;
Department of Mechanical Engineering
This paper develops a design optimization procedure in scroll-type compressor (STC). By integrating the verified STC simulation model with an optimum solver, a frictional losses reduced problem of bearing components has been investigated. After the optimum search, the frictional losses can be reduced in range of 14.1-18.1% at all testing conditions with specified constraints. Herein, the design modifications of crank and upper bearings are compromised between reduction of frictional losses and maintenance of hydrodynamic lubrication. In addition, the narrower and shorter design of lower bearing and smaller one of thrust bearing can reduce frictional losses too. Furthermore, wider selection of materials in all the bearings can be adopted with the satisfied strength constraint. By using this procedure, various optimum combinations of parameters can be found for different STC design considerations. (C) 2010 Elsevier Ltd and IIR. All rights reserved.