Browsing by Author "Wang, CC"

Now showing 1 - 20 of 68

A 1.5-V, 2.4GHz CMOS low-noise amplifier
(2000)
Yang, JN
;
Lee, CY
;
Hsu, TY
;
Hsu, TR
;
Wang, CC
A 2.4GHz low noise amplifier has been designed in a standard CMOS 0-35 um process. The transistor model is Bsim3 for 0.35um process. The amplifier provides a forward gain of 33dB with a noise figure only 0.92dB while drawing 17mw from a 1.5 V supply. Design simulation results are presented In this paper.
A cost-effective forward recovery checkpointing scheme in multiprocessor systems
(2000-01-01)
Wang, KC
;
Wang, CC
;
資訊工程學系
;
Department of Computer Science
This paper proposes a novel and cost-effective forward recovery checkpointing scheme fur multiprocessor systems with duplex modular redundancy. In our scheme, one processing module is selected to retry the questionable checkpoint, and the other processing module executes toward the next checkpoint ii a mismatched comparison between the two processing modules occurs at any checkpoint. Those schemes using a spare module to retry need much time to initiate the module, and the extra cost is high. Although the traditional rollback scheme retries the questionable checkpoint without any spare module, it has longer average completion time than our scheme for a job under any fault distribution. In our scheme, besides transient faults, permanent faults can be located as well. Experimental results based on our mathematical models demonstrate that, under burst errors, the average completion time of our scheme is reduced by 50% compared with that of the traditional rollback and is comparable with that of the scheme using a spare module to retry. In addition, our scheme has the least total execution time (the most cost-effectiveness) among the three schemes under any fault distribution.
A homophonic DES
(1998-06-30)
Hsieh, TM
;
Yeh, YS
;
Hsieh, YC
;
Wang, CC
;
資訊科學與工程研究所
In this paper, we propose a variant of DES called a homophonic DES. The DES algorithm is strengthened by adding some random bits into the plaintext, which are placed in particular positions to maximize diffusion, and to resist differential attack. (C) 1998 Elsevier Science B.V. All rights reserved.
A method for improved bicycle shifting performance
(1997)
Wang, CC
;
Tseng, CH
;
Fong, ZH
;
交大名義發表
;
機械工程學系
The overwhelming majority of bicycles, the most common human-powered vehicles (HPVs), are equipped with sophisticated derailleur systems that serve the same purpose as transmissions in motor vehicles: enabling more efficient use of input power through selection of suitable gear reduction ratios. This paper presents a method for improving the performance of bicycle derailleur systems by modifying sprocket shape to eliminate jerkiness, slippage and rattling noise, and guide chain movement from one gear to another mole quickly and directly. The sprocket modification CAD/CAM program, and an integrated optimization tool, were developed on an IRIS INDIGO/4000 workstation.
A novel driving scheme for FLCD
(1996)
Wu, JC
;
Wang, CC
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
An automated robot calibration system based on a variable D-H parameter model
(1996)
Young, KY
;
Chen, JJ
;
Wang, CC
;
交大名義發表
;
電控工程研究所
Current robot calibration schemes usually employ calibration models with constant error parameters. Consequently, they are inevitably subject to a certain degree of locality, i.e., the calibrated error parameters (CEPs) will produce the desired accuracy only in certain regions of the robot workspace. This is mainly because of incomplete modeling of errors, resulting in imprecision, and because only a limited amount of measured data are available for identifying CEPs. To deal with the locality phenomenon, CEPs that vary in different regions of the robot workspace may be more appropriate Hence, we propose a variable D-H (Denavit and Hartenberg [2]) parameter model to formulate variations of CEPs. Simulations and experiments that verify the effectiveness of the proposed calibration system are described.
An experimental study of in-tube evaporation of R-22 inside a 6.5-mm smooth tube
(1998-06-01)
Wang, CC
;
Chiang, CS
;
Yu, JG
;
機械工程學系
;
Department of Mechanical Engineering
Two-phase flow pattern, friction, and heat transfer characteristics for R-22 inside a 6.5 mm smooth tube are reported in this study. The range of mass flux is between 50 and 700 kg/m(2) s. The flow pattern map proposed by Weisman et al. (Weisman, J., Duncan, D., Gibson, J., Crawford, T., 1979. Effect of fluid properties and pipe diameter on two-phase flow pattern in horizontal lines. Int. J. Multiphase Flow 5, 437-462) gave a satisfactory flow pattern prediction, and the Klimenko and Fyodorov (Klimenko, V.V., Fyodorov, M., 1990. Prediction of heat transfer for two-phase forced flow in channels of different orientation. In: Proceedings of the Ninth International Heat Transfer Conference, vol. 6, pp. 65-70) criterion shows an excellent classification of the stratified and unstratified flow pattern. The two-phase multipliers are strongly related to the flow pattern, and it is found that the two-phase multiplier is dependent upon mass velocities for stratified-wavy flow pattern. In addition, the two-phase heat transfer coefficient for stratified-wavy flow pattern is found to be insensitive to the change of vapor quality, and is approximately proportional to q(0.6-0 7). (C) 1998 Elsevier Science Inc. All rights reserved.
Analysis of evaporation of non-azeotropic refrigerants in a horizontal tube
(1996-10-01)
Chiou, CB
;
Lu, DC
;
Wang, CC
;
機械工程學系
;
Department of Mechanical Engineering
Based on the two-phase separated model, a detailed one-dimensional model for binary mixtures had been proposed to study the in-tube evaporation in a horizontal tube. The present model can predict the detailed variation of the composition, temperature, heat transfer rate and pressure drop of various binary mixtures under constant heat flux, counter-flow, or parallel-flow conditions. The predicted results agree favorably with the Takamatsu et al. [Int. J. Neat Mass Transfer 36, 3555-3563 (1993)] and Jung et al. [Exp. Heat Transfer 2, 237-255 (1989)] experimental data. Also, it is found that the full evaporation of the non-azeotropic refrigerants may require a corresponding temperature higher than the saturation temperature of the less volatile component. The non-linear variation of the property plays an important role in the heat transfer and pressure drop characteristics of the refrigerant mixtures. Copyright (C) 1996 Elsevier Science Ltd.
Arsenic/phosphorus LDD optimization by taking advantage of phosphorus transient enhanced diffusion for high voltage input/output CMOS devices
(2002-01-01)
Wang, HCH
;
Wang, CC
;
Diaz, CH
;
Liew, BK
;
Sun, JYC
Optimization of a LDD doping profile to enhance hot carrier resistance in 3.3 V input/output CMOS devices has been performed by utilizing phosphorus transient enhanced diffusion (TED). Hot carrier effects in hybrid arsenic/phosphorus LDD nMOSFET's with and without TED are characterized comprehensively. Our result shows that the substrate current in a nMOSFET with phosphorus TED can be substantially reduced as compared to the one without TED. The reason is that the TED effect can yield a more graded n(-) LDD doping profile and thus a smaller lateral electric field. Further improvement of hot carrier reliability can be achieved by optimizing arsenic implant energy. Secondary ion mass spectrometry analysis for TED effect and two-dimensional (2-D) device simulation for electric field
Characteristics of air-water two-phase flow in a 3-mm smooth tube
(2000-10-01)
Wang, CC
;
Yang, KS
;
Chang, YJ
;
Lu, DC
;
機械工程學系
Two-phase flow pattern and friction characteristics for an air-water system in a 3.17 mm smooth tube are reported in this study. The range of mass flux is between 50 and 700 kg/m(2)s. The experimental data show that the two-phase friction multipliers are strongly related to the flow pattern. For a stratified-wavy flow pattern, a mass-flux dependence of the two-phase multipliers is seen. For a non-stratified flow pattern, the two-phase frictional multipliers are comparatively independent of mass flux. Correlations of the frictional multipliers are developed for stratified and non-stratified flow. To use the appropriate correlation in different regime, a simple criterion is proposed.
Characterization and fabrication of chimney-shaped metal field emitters
(1996-01-01)
Cheng, HC
;
Wang, CC
;
Ku, TK
;
Hsieh, IJ
;
電子工程學系及電子研究所
A novel fabrication technology has been successully developed for chimney-shaped metal field emitters in order to improve the electrical characterisitcs of field-emission devices. This technology is based on anisotropic dry etching and sputtering deposition of metal film as well as wet etching of the attached silicon. It enables easy fabrication of chimney-shaped field emitters with excellent uniformity and high reproducibility. The anode current of the chimney-shaped Cr field emitter array (FEA) is 36.3 mu-A at the applied voltage of 1100 V and the threshold voltage V-T, defined as that for which the anode current I-n reaches 1 mu-A is 787 V. The chimney-shaped Cr FEA emits a current thirty times higher than that from the cone-shaped Cr-clad FEA at the applied voltage of 1100 V. This can be attributed to the presence of many sharp tips along the edge of the chimney-shaped emitter. The degradation phenomenon is not observed because compensation occurs between these many sharp tips. Another merit of this technique is that only one photolithography mask is needed during processing.
Chimney-shaped and plateau-shaped gate electrode field emission arrays
(1998)
Tarntair, FG
;
Wang, CC
;
Hong, WK
;
Huang, HK
;
Cheng, HC
A triode structure of chimney-shaped field emitter arrays is proposed in this article. This triode structure includes the chimney-shaped emitter, thermal oxidation dioxide, and the plateau-shaped singlecrystalline silicon gate electrode. For the application of the matrix-addressable and large area flat panel display, the uniform structure of the emitters and the yield become critical manufacturing issues when attempting to control nano-meter size features. The uniformity and yield of the chimney-shaped emitters are very well controlled. The nano-sized gate-to-emitter separations can be created by the changing thickness of the insulator. The uniformity of the insulator and emitter material can be controlled within 3% which can be obtained by most large area thin film deposition tools, not by photolithography.
Chimney-shaped and plateau-shaped gate electrode field emission arrays
(1998)
Tarntair, FG
;
Wang, CC
;
Hong, WK
;
Huang, HK
;
Cheng, HC
A triode structure of chimney-shaped field emitter arrays is proposed in this article. This triode structure includes the chimney-shaped emitter, thermal oxidation dioxide, and the plateau-shaped singlecrystalline silicon gate electrode. For the application of the matrix-addressable and large area flat panel display, the uniform structure of the emitters and the yield become critical manufacturing issues when attempting to control nano-meter size features. The uniformity and yield of the chimney-shaped emitters are very well controlled. The nano-sized gate-to-emitter separations can be created by the changing thickness of the insulator. The uniformity of the insulator and emitter material can be controlled within 3% which can be obtained by most large area thin film deposition tools, not by photolithography.
Chimney-shaped and plateau-shaped gate electrode field emission arrays
(1998-01-01)
Tarntair, FG
;
Wang, CC
;
Hong, WK
;
Huang, HK
;
Cheng, HC
A triode structure of chimney-shaped field emitter arrays is proposed in this article. This triode structure includes the chimney-shaped emitter, thermal oxidation dioxide, and the plateau-shaped singlecrystalline silicon gate electrode. For the application of the matrix-addressable and large area flat panel display, the uniform structure of the emitters and the yield become critical manufacturing issues when attempting to control nano-meter size features. The uniformity and yield of the chimney-shaped emitters are very well controlled. The nano-sized gate-to-emitter separations can be created by the changing thickness of the insulator. The uniformity of the insulator and emitter material can be controlled within 3% which can be obtained by most large area thin film deposition tools, not by photolithography.
Comparison of time domain BEM for 2D elastodynamic
(1998-07-01)
Wang, CC
;
Liou, GS
;
土木工程學系
;
Department of Civil Engineering
The three (LC, QC and QL) new time domain BEM methods are compared with each other and with an analytical method, the Laplace domain BEM method and another time domain boundary element method by solving two example problems of a circular cylindrical cavity subjected to a suddenly applied internal pressure, and a finite bar subjected to a ramp-step loading. Numerical study reveals that the three (LC, QC and QL) new methods are more accurate and stable than the other numerical methods used for comparison. Demonstration of the numerical computational time versus time steps of the three BEM methods is also given for a simple two-dimensional elastodynamics problem of a bar with 12-quadratic-element mesh due to an end traction. The difference in computational times by QC and LC methods is small.
Comparisons of optical properties on meta- and para-linkages of copolymers for poly(phenylene vinylene) and poly(phenylene azomethine) with alkylthio group at the side chain
(2005-02-01)
Chang, CP
;
Wang, CC
;
Chao, CY
;
Lin, MS
;
應用化學系
Three series of soluble copolymers were synthesized: I, poly[m (or p)-phenylene (diacetonitrile) vinylene-co-methoxy-5-(2'-ethylhexylthio)-p-phynylene vinylene] (m-C=C(CN), p-C=C(CN)); II, poly[m (or p)-phenylene azomethine-co-2-methoxy-5-(2'-ethylhexylthio)-p-phenylene azomethine] (m-C=N, p-C=N); III, poly[m (or p)-phenylene vinylene-co-2-methoxy-5-(2'-ethylhexythio)-p-phenyle vinylene] (m-C=C, p-C=C). Of all these copolymers, the copolymers containing meta-linkage showed glass transition temperatures (T-g's) approximately 10 degrees C to 30 degrees C lower than those of the corresponding para-linkage copolymers because of lower crystallinity. 5% weight loss of all the copolymers occurred at around 381 to 344 degrees C. Copolymers of the meta-linkage also caused a relative asymmetry and irregularity of the copolymer main chain, thus leading to a decrease of effective conjugation length and a reduction of the molecular aggregation: this subsequently led to less excimer formation. These phenomena can be evidenced from the blue-shift of PL emission, 15 to 49 nm for the meta-linkage copolymers compared with the para-linkage copolymers. In addition, due to the lesser electron-donating capability of the sulfur atom, m-C=C, p-C=C and p-C=N containing the alkylthio group indicated a blue shift of 8 to 24 nm, when compared with those copolymers of similar structures containing the alkyloxy group as reported in the literature. Since series H contains strong electron-withdrawing -C=N- at the main chain, and series I contains even stronger electron-withdrawing cyano group, thus, the observed lambda(max) are in the order: series I [m-C=C(CN), p-C=C(CN)] > series II [mC=N, p-C=N] > series III [m-C=C, p-C=C]. Furthermore, since in series II, the lone pair electrons on the -C=N- main chain would overlap partially with the six pi electrons in the phenyl ring, and decrease the coplanar nature of the main chain, thus their PL emission intensities were less than those of series I and III. Finally, a device of the structure (ITO/PEDOT: PSS/m-CC(CN)/LiF/Al) was constructed, and a yellow light of lambda(max) = 570 nm was observed.
Comprehensive study of convex-louver and wavy fin-and-tube heat exchangers
(1998-07-01)
Wang, CC
;
Tsai, YM
;
Lu, DC
;
機械工程學系
;
Department of Mechanical Engineering
A comprehensive study to investigate the heat transfer and friction characteristics of convex-louver and wavy fin-and-tube heat exchangers was carried out in this study. A total of 14 samples of heat exchangers, including seven convex-louver and seven wavy fin samples having identical waffle heights, were tested and compared in the present investigation. The effects of the number of tube row and fin pitch on the thermal-hydraulic characteristics were also reported. Results were presented as plots of Fanning friction factor f and the Colburn j factor against a Reynolds number based on a tube collar diameter in the range of 3 x 10(2) to 8 x 10(3).
Construct message authentication code with one-way hash functions and block ciphers
(1999-02-01)
Yeh, YS
;
Wang, CC
;
資訊科學與工程研究所
;
Institute of Computer Science and Engineering
We suggest an MAC scheme which combines a hash function and an block cipher in order. We strengthen this scheme to prevent the problem of leaking the intermediate hash value between the hash function and the block cipher by additional random bits. The requirements to the used hash function are loosely. Security of the proposed scheme is heavily dependent on the underlying block cipher. This scheme is efficient on software implementation for processing long messages and has clear security properties.
Content-based color trademark retrieval system using hit statistic
(2002-08-01)
Wang, CC
;
Chen, LH
;
資訊工程學系
;
Department of Computer Science
This paper proposes a content-based color trademark retrieval system. First, the edges of each color trademark are detected. Then, the smallest circle that covers the trademark is derived. Based on the smallest circle and edges, the feature called hit statistic on a dartboard of the color trademark is extracted. Using this feature, this paper constructs an efficient and simple color trademark retrieval system, which is robust to rotation, translation, scaling and some geometric distortions. Some experiments are conducted to compare the proposed system with the existing one using Zernike moment, and the results show that the proposed system is superior to that using Zernike moment.
Data line driver design for a 10'' 480x640x3 color FED
(1996)
Wang, CC
;
Wu, JC
;
Huang, CM
;
交大名義發表
;
電子工程學系及電子研究所
A data line driver with 120 outputs and capable of producing contrast ratio over 100 for a 10'' 480x(640x3) pixels color field emission display (FED) panel have been designed. Three phase clocks were used to reduce the maximum operating frequency to 22.68Mhz. A class AB Op Amp was used as the analog output buffer to reduce the power dissipation. The chip is implemented in a 24V CMOS process, chip size is 7620 mu m x 17500 mu m.