Browsing by Issue Date, starting with "2001-09"

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A tabu search based maximum descent algorithm for VQ codebook design
(2001-09-01)
Huang, HC
;
Chu, SC
;
Pan, JS
;
Lu, ZM
;
電子工程學系及電子研究所
A maximum descent (MD) method has been proposed for vector quantization (VQ) codebook design. Compared with the traditional generalized Lloyd algorithm (GLA), the MD algorithm achieves better codebook performance with far less computation time. However, searching for the optimal partitioning hyperplane of a multidimensional cluster is a difficult problem in the MD algorithm. Three partition techniques have been proposed for the MD method in the literature. In this paper, a new partition technique based on the tabu search (TS) approach is presented for the MD algorithm. Experimental results show that the tabu search based MD algorithm can produce a better codebook than can the conventional MD algorithms.
Forecast of shear spinning force and surface roughness of spun cones by employing regression analysis
(2001-09-01)
Chen, MD
;
Hsu, RQ
;
Fuh, KH
;
機械工程學系
;
Department of Mechanical Engineering
A series of shear spinning experiments has been performed to produce axi-symmetric cones from blank sheet. The experiments investigated influences of roller nose radius, mandrel revolution and roller feed on the spinning force and the inside/outside surface roughness of spun cone. Statistical analysis was adopted to construct the regression equations governing these parameters. Independent experiments verified the findings. It was discovered that the established regression equations possess a significant degree of reliability. (C) 2001 Elsevier Science Ltd. All rights reserved.
The simulation of application of high transmittance AttPSM for sub-100 nm pattern in 248 nm lithography
(2001-09-01)
Lin, CM
;
Loong, WA
;
應用化學系
;
Department of Applied Chemistry
In contrast to the normal transmittance (T < 10%) attenuated phase-shifting mask (AttPSM), the high transmittance AttPSM assisted with Cr scattering bars could enhance the resolution of aerial image down to about 0.1 mum isolated line in clear-field mask. With transmittance T = 35% of the 0.1-mum isolated line as embedded layer, the optimized width of scattering bars is 0.085 mum, the distance between Cr scattering bar and 0.1 mum isolated line is 0.205 mum, and DOF is 0.53 Rm under the optimized quadrupole illumination with 0.51/0.27 (sigma (offset)/sigma (radius)). Compared to transmittance 5 and 15% of embedded layer, the negative and positive factors of mask error enhancement factor (MEEF) could be kept in the range of - 2 to + 2 for isolated lines wider than 80 mum at transmittance 35%, assisted with the 0.085-mum width of Cr scattering bars. (C) 2001 Published by Elsevier Science B.V.
Contact ratios and transmission errors of a helical gear set with involute-teeth pinion and modified-circular-arc-teeth gear
(2001-09-01)
Chen, YC
;
Tsay, CB
;
機械工程學系
;
Department of Mechanical Engineering
Contact ratio (CR) and transmission error (TE) are two significant indices for gear tooth strength and dynamics. This work investigated the CR, contact teeth (CT) and TE of a helical gear pair, composed of an involute pinion and a modified circular-arc gear. Point contact and built-in parabolic TE are obtained due to the modification of the gear's tooth profile. Tooth contact analysis (TCA) is applied to determine the TE as well as the CR of the proposed helical gear set under various assembly condition. The effect of gear design parameters on the CRs and TEs are also investigated in numerical examples.
【學術專欄】製作固定假牙時根管治療的考量
(國立陽明大學牙醫校友會, 2001-09)
楊淑芬
Capability indices for processes with asymmetric tolerances
(2001-09-01)
Chen, KS
;
Pearn, WL
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
Process capability indices (PCIs) for processes with symmetric tolerances have received substantial research attention. But, PCIs for processes with asymmetric tolerances have been comparatively neglected. Recently, Boyles (1994) reviewed the existing PCI literature and proposed several new indices to handle processes with asymmetric tolerances. In this paper we analyze PCIs based on various process characteristics., then introduce a new class of capability indices to handle processes with asymmetric tolerances. The proposed new indices are compared with existing PCIs in terms of process yield, process centering, and process characteristic related to loss functions. The results indicate that the new indices are superior to the existing capability indices, and provide greater accuracy in current applications using PCIs to measure process potential and performance.
管管詩句
(2001-09-01)
管管
A three-port 180-degree antenna hybrid: Design and applications
(2001-09-01)
Chou, YH
;
Chung, SJ
;
電信工程研究所
;
Institute of Communications Engineering
In this paper, a novel three-port antenna structure, named 180 degrees antenna hybrid, is proposed and demonstrated. This structure is composed of a Wilkinson power divider with the isolation resistor replaced by an aperture-coupled patch antenna. The equivalent series impedance of the antenna can be adjusted to the required one by properly choosing the dimensions of the patch and the coupling aperture. When a signal is fed to the balanced port of this antenna hybrid, the power is equally split, with equal phases, to the two unbalanced ports. No power is radiated out from the antenna. In the other hand, a signal received from the antenna will be split with equal power but 180 phase difference to the two unbalanced ports. The balanced port is an isolation port. The measurement results showed good agreement with the characteristics to be designed. Three applications of this 180 degrees antenna hybrid are introduced, that is, a balanced mixer, an active transmitting antenna, and a dual-radiation-mode antenna array. The balanced mixer was constructed with diodes directly mounted on the two unbalanced ports of the antenna hybrid. The LO signal is fed from the balanced port and RF signal is received from the antenna. The active transmitting antenna was implemented with feedback configuration. The route from one of the unbalanced port to the balanced port of the antenna hybrid was used as the feedback path. A locking signal may be injected from the other unbalanced port. Finally, through a three-quarter-wavelength microstrip line, the balanced port of the antenna hybrid was connected to another aperture-coupled patch antenna to form a dual-radiation-mode antenna array. The in-phase and out-of-phase radiation patterns of this two-element array can be obtained from two unbalanced ports of the antenna hybrid, respectively.
Molecular dynamics simulation of microscopic droplet spread on rough surfaces
(2001-09-01)
Hwang, CC
;
Jeng, YR
;
Hsu, YL
;
Chang, JG
;
機械工程學系
This study uses molecular dynamics simulations to elucidate the spreading behaviour of a liquid droplet oil a rough solid surface. The Lennard-Jones potential energy model is adopted as the interaction model between the liquid and the solid molecules. The paper considers two typos of rough surface: periodic and random. These surfaces are characterized by their roughness height and their spatial variation. For a periodic surface, the roughness height is defined by the amplitude, A, while for a random surface, it is defined in terms of the standard deviation of the roughness height, sigma. Regarding the spatial variation of the surface, a periodic surface is characterized by the wavelength, lambda, while the random surface is characterized by its autocorrelation length, L. Simulation results indicate that the characteristics of the rough surface can significantly influence spreading behaviour, in terms of final equilibrium time, spreading radius, and spreading topography. It is observed that the effects of roughness height and spatial variation are broadly similar for both periodic and random surfaces. It is found that increasing roughness height and decreasing spatial periodicity both prolong the final equilibrium time, and that the filial spreading radius decreases with increasing roughness height and increases with larger spatial periodicity.
An investigation of scanning capacitance microscopy on iron-contaminated p-type silicon
(2001-09-01)
Chang, MN
;
Chang, TY
;
Pan, FM
;
Wu, BW
;
Lei, TF
Scanning capacitance microscopy (SCM) is employed to examine iron-contaminated p-type Si samples. For slightly contaminated samples, a dc voltage of -0.8 V, applied between the sample and the conductive tip, induces positive trapped charges. Owing to the existence of these charges, the region containing trapped charges exhibits an obviously low dC/dV signal. According to contact-mode atomic force microscopy results, the surface, morphology has little effect on the SCM signal. The experimental results indicate that SCM is capable of detecting the distribution of oxidation-related. defects which cannot otherwise be easily observed by atomic force microscopy and transmission electron microscopy. (C) 2001 The Electrochemical Society.
【校友會會務】對陽明牙醫及校友會之期許
(國立陽明大學牙醫校友會, 2001-09)
戴溪炎
管管詩句
(2001-09-01)
管管
Influence of barrier growth temperature on the properties of InGaN/GaN quantum Well
(2001-09-01)
Wen, TC
;
Lee, WI
;
電子物理學系
;
友訊交大聯合研發中心
;
Department of Electrophysics
In this study we investigate the effect of barrier growth temperature on the properties of InGaN/GaN multiple quantum wells. Double-crystal X-ray diffraction of MQW structures indicates that increasing the barrier growth temperature will reduce the well thickness. However, the photoluminescence peak wavelength shift is greater than the change of in the effective bandgap due to the reduction of well width. In addition to the reduction of well width, the determination of the origin of the significant blue shift in the photoluminescence peak wavelength should also take the strain effect into account.
Improvements in both thermal stability of Ni-silicide and electrical reliability of gate oxides using a stacked polysilicon gate structure
(2001-09-01)
Lee, JW
;
Lin, SX
;
Lei, TF
;
Lee, CL
;
電子工程學系及電子研究所
A process design is presented for improving the thermal stability of Ni-silicide (nickel-silicide) using a stacked polysilicon gate structure. The Ni-silicide formed has low sheet resistance up to 800 degreesC on a silicidation process. Additionally, the metal-oxide-semiconductor (MOS) capacitors fabricated using these proposed gate structures demonstrate higher electrical reliability for gate oxides than those of nonstacked films. That is, the gate oxides of the MOS capacitors were only slightly degraded after silicidation step at 800 degreesC. In conclusion, the Ni-silicide formed on those stacked polysilicon gates are attractive in fabricating ultralarge scale integration (ULSI) circuits because both the thermal stability of Ni-silicide and the reliability of gate oxides are improved simultaneously. (C) 2001 The Electrochemical Society.
Method for solving quasi-concave and non-concave fuzzy multi-objective programming problems
(2001-09-01)
Yu, CS
;
Li, HL
;
資訊管理與財務金融系註：原資管所+財金所
;
Department of Information Management and Finance
This paper proposes a method based on linear programming techniques to treat quasi-concave and non-concave fuzzy multi-objective programming (FMOP) problems. The proposed method initially presents a piecewise linear expression to interpreting a quasi-concave membership function. Then we find the convex-type break points acid transform all quasi-concave membership functions into concave functions. After that, the converted program is solved by linear programming techniques to obtain a global optimum. Tn addition to not containing any of the zero-one variables, the proposed method does not require dividing the quasi-concave FMOP problem into large sub-problems as in conventional methods. The extension of the proposed method can treat general non-concave FMOP problems by merely adding less number of zero-one variables. (C) 2001 Elsevier Science B.V. All rights reserved.
【校友會會務】經營管理-ISO認證的有效性評估
(國立陽明大學牙醫校友會, 2001-09)
費鴻泰
【學院報導】口腔生物研究所簡介
(國立陽明大學牙醫校友會, 2001-09)
張國威
A unified interface for integrating information retrieval
(2001-09-01)
Chang, YS
;
Ho, MH
;
Yuan, SM
;
資訊工程學系
;
Department of Computer Science
In this paper, we propose a unified interface and a flexible architecture for querying various information sources on the Internet and the WWW using both a popular object model and a data model. We propose an Integrated Information Retrieval MR) service based on the Common Object Service Specification (COSS) for Common Object Request Broker Architecture (CORBA) and apply the Document Type Definition (DTD) of eXtensible Mark-up Language XML) to define the metadata of information sources for sharing the ontology between mediator and wrappers, The objective of using the IIR design is not only to provide programmers with a uniform interface for coding a software application that can query a variety of information sources on the Internet, but also to create a flexible and extensible environment that easily allows system developers to add new or updated wrappers to the system. (C) 2001 Elsevier Science B.V. All rights reserved.
Asymptotic rejection of periodic disturbances with fixed or varying period
(2001-09-01)
Yu, SH
;
Hu, JS
;
電控工程研究所
;
Institute of Electrical and Control Engineering
A constructive derivation of repetitive control is obtained, through attempting to derive a control law for asymptotic rejection of periodic disturbances. This derivation not only reveals a close relationship between iterative operator inversion and repetitive control, but also suggests a unified design method for a learning control algorithm. Also, based on the observation, digital repetitive control can be generalized to reject periodic disturbance whose period is not exactly an integer multiple of the sampling interval, This study introduces a delay filter in the digital repetitive control law, which optimally interpolates the signal between samples, thus effectively reconstructing the signal of the previous period and making the learning process of repetitive control successful. The proposed optimal delay filter can be updated easily according to different signal periods. Thus it is specifically suitable for on-line timing when the signal period is changing. Compared with the available tuning methods, the proposed tuning method has excellent steady-state performance while maintaining fast transient and system robustness. The simulations on active noise cancellation within a duct confirm the superiority of this tuning method.
【校友會會務】校友會捐款芳名錄
(國立陽明大學牙醫校友會, 2001-09)