Browsing by Issue Date, starting with "1997-11-01"

Now showing 1 - 20 of 83321

Effects of volume fraction of reinforcement on tensile and creep properties of in-situ TiB/Ti MMC
(1997-11-01)
Tsang, HT
;
Chao, CG
;
Ma, CY
;
材料科學與工程學系
;
Department of Materials Science and Engineering
The TEOS CVD oxide deposited on phosphorus in situ doped polysilicon with rapid thermal annealing
(1997-11-01)
Kao, CH
;
Lai, CS
;
Lee, CL
;
交大名義發表
;
電子工程學系及電子研究所
A TEOS oxide deposited on the phosphorus in situ doped polysilicon annealed with RTA is shown to have good electrical characteristics such as a high breakdown field (>12 MV/cm), especially for the positive bias, and a large Qbd (26 Coul/cm(2)). The improvement is believed to be due to the relatively smooth surface of the in situ doped polysilicon and the reduction of the trapping density by RTA.
An enhanced zero-one optimal path set selection method
(1997-11-01)
Chung, CG
;
Lee, JG
;
交大名義發表
;
資訊工程學系
;
National Chiao Tung University
One issue in structural program testing is how to select a mimimal set of test paths to meet certain test requirements. This is referred to as the optimal path set selection problem. The previously proposed zero-one optimal path set selection method is a generalized method that can be applied to most coverage criteria. However, the major drawback of this method is that for a large program the computation may take ten or more hours because the computation is exponentially proportional to the number of candidate paths and proportional to the number of components to be covered. To alleviate the drawback, this paper enhances the method by (1) defining five reduction rules, and (2) reusing previously selected path sets to reduce both the number of candidate paths and the number of components to be covered. Since both the number of candidate paths and the number of components to be covered are reduced, the computation time can be greatly reduced. In addition, an efficient approach to handling infeasible paths is proposed. An evaluation of the enhanced zero-one method, the original zero-one method, and a greedy method is executed and the result is presented. (C) 1997 Elsevier Science Inc.
An ART-based fuzzy adaptive learning control network
(1997-11-01)
Lin, CJ
;
Lin, CT
;
交大名義發表
;
電控工程研究所
;
National Chiao Tung University
This paper addresses the structure and an associated on-line learning algorithm of a feedforward multilayered connectionist network for realizing the basic elements and functions of a traditional fuzzy logic controller. The proposed fuzzy adaptive learning control network (FALCON) can be contrasted with the traditional fuzzy logic control systems in their network structure and learning ability. An on-line structure/parameter learning algorithm called FALCON-ART is proposed for constructing the FALCON dynamically. It combines the backpropagation learning scheme for parameter learning and the fuzzy ART algorithm for structure learning. The FALCON-ART has some important features. First of all, it partitions the input state space and output control space using irregular fuzzy hyperboxes according to the distribution of training data. In many existing fuzzy or neural fuzzy control systems, the input and output spaces are always partitioned into ''grids.'' As the number of input/output variables increases, the number of partitioned grids will grow combinatorially. To avoid the problem of combinatorial growing of partitioned grids in some complex systems, the FALCON-ART partitions the input/output spaces in a flexible way based on the distribution of training data. Second, the FALCON-ART can create and train the FALCON in a highly autonomous way. In its initial form, there is no membership function, fuzzy partition, and fuzzy logic rule. They are created and begin to grow as the first training pattern arrives. Thus, the users need not give it any a priori knowledge or even any initial information on these. More notably, the FALCON-ART can on-line partition the input/output spaces, tune membership functions, find proper fuzzy logic rules, and annihilate redundant rules dynamically upon receiving online incoming training data. Computer simulations have been conducted to illustrate the performance and applicability of the proposed system.
Edge detection and edge-preserved compression for error-diffused images
(1997-11-01)
Han, WY
;
Lin, JC
;
資訊工程學系
;
Department of Computer Science
In this paper, a new approach to edge detection and image compression of bilevel error-diffused images is proposed. The proposed approach is directly applied to the error-diffused images without any inverse halftoning technique. The main idea behind the proposed edge detection method is to compute the consistency value of each pixel of the error-diffused image, and the computed values are then clustered into two classes to obtain the desired edges. Here, the consistency value is a function of the mass center and geometric center of the window; more precisely, it represents the possibility that the area covered by the window can be uniform. As for compression, each error-diffused input image is compressed by dividing the image into non-overlapping blocks with size 8x8, then each highly-consistent block is encoded by its average illumination, and each lowly-consistent block is transmitted directly using the original bitmap. The threshold to distinguish these two kinds of blocks is automatically calculated based on the compression rate required by the users. The complexity of our compression technique is low, and this fast method can be used in real-time application. (C) 1997 Elsevier Science Ltd. All rights reserved.
Observation and computation of vortex and/or reverse flow development in mixed convection of air in a slightly inclined rectangular duct
(1997-11-01)
Lin, WL
;
Lin, TF
;
交大名義發表
;
機械工程學系
;
National Chiao Tung University
Combined pow visualization and conjugated numerical heat transfer analysis were carried out to study the axial evolution of the buoyancy induced secondary vortex and reverse pow in a mixed convective air pow through a bottom heated, slightly inclined rectangular duct. Results were obtained for the Grashof number Gr ranging from 1.6 x 10(3) to 2.8 x 10(5), inclined angle phi from -20 deg to 26 deg and the Reynolds number Re below 102 covering the steady and time dependent flows. For the buoyancy-opposing case, at a certain critical buoyancy-to-inertia ratio depending on the Re and phi both the experimental and numerical results clearly showed the generation of the longitudinal vortex rolls in the entry half of the duct and a slender reverse pow zone was induced near the exit end of the duct. At a higher buoyancy-to-inertia ratio the stronger reverse flow moves upstream and is in a time periodic snaking motion which is considered to result from the Kelvin-Helmholtz instability associated with the two counter flow streams, namely, the downstream moving longitudinal vortex rolls and the upstream moving reverse flow. Through the viscous shearing effects the strong snaking reverse flow induces a number of eddies moving along it and the longitudinal rolls are pushed towards the duct sides. This strong interaction between the vortex flow and reverse pow leads to an earlier transition to turbulence. A correlation equation was proposed for the penetration length of the reverse flow. However for buoyancy-assisting pow no reverse flow is induced and the longitudinal vortex rolls prevail for the buoyancy-to-inertia ratio up to 2.8 X 10(5). Significant conjugated heat transfer effects were noted from the numerical results.
Four-wave mixing between a soliton and noise in a system with large amplifier spacing
(1997-11-01)
Chi, S
;
Kao, CY
;
Wen, S
;
光電工程學系
;
Department of Photonics
Depletion of soliton energy by four-wave mixing between a soliton and amplifier noise in a system with 100-km amplifier spacing is studied. Dispersion exponentially decreasing fiber is used as transmission fiber. Improvement of the system by the use of a sliding-frequency filter to reduce noise power and the depletion of soliton energy is shown. The system can be further improved by compensation for depleted soliton energy. (C) 1997 Optical Society of America.
管管作品四首
(1997-11-01)
管管
An enhanced zero-one optimal path set selection method
(1997-11-01)
Chung, CG
;
Lee, JG
;
資訊工程學系
;
Department of Computer Science
One issue in structural program testing is how to select a mimimal set of test paths to meet certain test requirements. This is referred to as the optimal path set selection problem. The previously proposed zero-one optimal path set selection method is a generalized method that can be applied to most coverage criteria. However, the major drawback of this method is that for a large program the computation may take ten or more hours because the computation is exponentially proportional to the number of candidate paths and proportional to the number of components to be covered. To alleviate the drawback, this paper enhances the method by (1) defining five reduction rules, and (2) reusing previously selected path sets to reduce both the number of candidate paths and the number of components to be covered. Since both the number of candidate paths and the number of components to be covered are reduced, the computation time can be greatly reduced. In addition, an efficient approach to handling infeasible paths is proposed. An evaluation of the enhanced zero-one method, the original zero-one method, and a greedy method is executed and the result is presented. (C) 1997 Elsevier Science Inc.
The microstructure of As precipitates in Si delta-doped GaAs grown by low-temperature molecular beam epitaxy
(1997-11-01)
Hsieh, LZ
;
Huang, JH
;
Su, ZA
;
Guo, XJ
;
Shih, HC
The structure relationship of the As precipitates found in post-annealed Si delta-doped GaAs layers grown by low-temperature molecular beam epitaxy is elucidated by transmission electron microscopy (TEM). There are six extra spots around the diffraction pattern of GaAs for a sample annealed at 700 degrees C. The As precipitates and GaAs matrix are found to be semicoherent with the hexagonal [-1-21](As) parallel to the cubic [110](GaAs). Because of the different lattice constants and Bravias lattices between GaAs and As precipitates, these extra spots are formed by double-diffraction effects. The high-resolution TEM images show two types of Moire fringes. One is the parallel Moire pattern and the other is the rotation Moire pattern. The relative positions of the extra spots in the diffraction pattern correspond to the orientation and spacing of Moire fringes.
FPGA realization of space-vector PWM control IC for three-phase PWM inverters
(1997-11-01)
Tzou, YY
;
Hsu, HJ
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This paper presents a new circuit realization of the space-vector pulse-width modulation (SVPWM) strategy. An SVPWM control integrated circuit (IC) has been developed using the state-of-the-art field-programmable gate array (FPGA) technology. The proposed SVPWM control scheme can be realized using only a single FPGA (XC4010) from Xilinx, Inc. The output fundamental frequency can be adjusted from 0.094 to 1500 Hz. The pulse-width modulation (PWM) switching frequency can be set from 381 Hz to 48.84 kHz. The delay time for the PWM gating signals is adjustable. This SVPWM IC can also be included in the digital current control loop for stator current regulation. The designed SVPWM IC can be incorporated with a digital signal processor (DSP) to provide a simple and effective solution for high-performance ac drives. Simulation and experimental results are given to verify the implemented SVPWM control IC.
A unified approach to profiling the lateral distributions of both oxide charge and interface states in n-MOSFET's under various bias stress conditions
(1997-11-01)
Cheng, SM
;
Yih, CM
;
Yeh, JC
;
Kuo, SN
;
Chung, SS
A new and accurate technique that allows the simultaneous determination of the spatial distributions of both interface states (N-it) and oxide charge (Q(ox)) will be presented. The gated-diode current measurement in combination with the gate-induced drain leakage (GIDL) current were performed to monitor the generation of both N-it and Q(ox) in n-MOSFET's. A special detrapping technique and simple calculations have been developed, from which the spatial distributions of both N-it and Q(ox) under various bias stress conditions, such as the hot-electron stress (I-G,I-max), I-B,I-max, and hot-hole stresses, can be determined. The calculation of gated-diode current by incorporating the extracted profiles of N-it and Q(ox) has been justified from numerical simulation. Results show very good agreement with the experimental results. The extracted interface damages for hot-electron and hot-hole stresses have very important applications for the study of hot-carrier reliability issues, in particular, on the design of flash EPROM, (EPROM)-P-2 cells since the above stress conditions, such as the I-G,I-max and hot-hole stress, are the major operating conditions for device programming and erasing, respectively.
Effects of RCA clean-up procedures on the formation of roughened poly-Si electrodes for high-density DRAMs' capacitors
(1997-11-01)
Liu, HW
;
Lai, WK
;
Yu, SY
;
Huang, SC
;
Cheng, HC
A novel structure, the phosphorus-implanted poly-Si films treated with phosphoric acid (H3PO4) and cleaned by standard RCA cleanup procedures, has been demonstrated as the bottom electrodes of DRAMs' stacked capacitors. After the H3PO4 treatment and RCA cleaning process, micro-island structures are formed on the poly-Si surface of the storage electrodes, The NH4OH + H2O2 + H2O (SC-1) solution in the RCA cleaning procedures is the main component to change the porous surfaces and engraved structures, formed by H3PO4 treatment, into micro-islands. Although the electrical properties are slightly degraded compared to the control samples, but they fulfill the requirements of high-density DRAMs, resulting from the increment of cell capacitance. (C) 1997 Elsevier Science S.A.
A fast motion estimation algorithm based on the block sum pyramid
(1997-11-01)
Lee, CH
;
Chen, LH
;
資訊工程學系
;
Department of Computer Science
In this correspondence, a fast approach to motion estimation is presented. The algorithm uses the block sum pyramid to eliminate unnecessary search positions. It first constructs the sum pyramid structure of a block. Successive elimination is then performed hierarchically from the top level to the bottom level of the pyramid. Many search positions can be shipped from being considered as the best motion vector and, thus, the search complexity can be reduced. The algorithm can achieve the same estimation accuracy as the full search block matching algorithm with much lass computation time.
A heuristic approach to generating file spanning trees for reliability analysis of distributed computing systems
(1997-11-01)
Chen, DJ
;
Chen, RS
;
Huang, TH
;
資訊科學與工程研究所
;
Institute of Computer Science and Engineering
The reliability of Distributed Computing Systems (DCS) in terms of Distributed Program Reliability (DPR) and Distributed System Reliability (DSR) has been studied intensively. Current reliability algorithms available for the analysis of DPR and DSR include MFST, FARE, FST, and FST-SPR. This paper presents a reliability algorithm, called HRFST, that eliminates the need to search a spanning tree during each subgraph generation. The HRFST algorithm reduces both the number of subgraphs (or trees) generated and the actual execution time required for analysis of DPR and DSR. Examination of several sample cases shows that the HRFST algorithm is more efficient than the FST-SPR algorithm.
管管作品四首
(1997-11-01)
管管
An efficient communication structure for decentralized algorithms with fault tolerance
(1997-11-01)
Yuan, SM
;
Agrawala, AK
;
資訊工程學系
;
Department of Computer Science
Decentralized algorithms can be characterized by successive rounds of message interchanges. Several communication structures have been proposed to design decentralized algorithms such as diffusion computations, logically fully connected structures and neighbouring-set communication structures. In this paper, we present a new communication structure, called KDAMS, which can be used to design message and bit optimal decentralized algorithms for evaluating associative and commutative functions which include distributed transaction commitment and extrema finding. In addition, the KDAMS has the potential for easily imposing fault-tolerant mechanisms.
An ART-based fuzzy adaptive learning control network
(1997-11-01)
Lin, CJ
;
Lin, CT
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This paper addresses the structure and an associated on-line learning algorithm of a feedforward multilayered connectionist network for realizing the basic elements and functions of a traditional fuzzy logic controller. The proposed fuzzy adaptive learning control network (FALCON) can be contrasted with the traditional fuzzy logic control systems in their network structure and learning ability. An on-line structure/parameter learning algorithm called FALCON-ART is proposed for constructing the FALCON dynamically. It combines the backpropagation learning scheme for parameter learning and the fuzzy ART algorithm for structure learning. The FALCON-ART has some important features. First of all, it partitions the input state space and output control space using irregular fuzzy hyperboxes according to the distribution of training data. In many existing fuzzy or neural fuzzy control systems, the input and output spaces are always partitioned into ''grids.'' As the number of input/output variables increases, the number of partitioned grids will grow combinatorially. To avoid the problem of combinatorial growing of partitioned grids in some complex systems, the FALCON-ART partitions the input/output spaces in a flexible way based on the distribution of training data. Second, the FALCON-ART can create and train the FALCON in a highly autonomous way. In its initial form, there is no membership function, fuzzy partition, and fuzzy logic rule. They are created and begin to grow as the first training pattern arrives. Thus, the users need not give it any a priori knowledge or even any initial information on these. More notably, the FALCON-ART can on-line partition the input/output spaces, tune membership functions, find proper fuzzy logic rules, and annihilate redundant rules dynamically upon receiving online incoming training data. Computer simulations have been conducted to illustrate the performance and applicability of the proposed system.
管管作品四首
(1997-11-01)
管管
Biotreatment of ammonia from air by an immobilized Arthrobacter oxydans CH8 biofilter
(1997-11-01)
Chung, YC
;
Huang, CP
;
Tseng, CP
;
環境工程研究所
;
生物科技學系
A heterotrophic Arthrobacter oxydans CH8 that was capable of removing NH3 from NH3 containing gas was isolated from livestock farming wastewater. The A. oxydans CH8 was immobilized with calcium alginate packed into filter column. Metered NH3-containing gas was partially humidified and passed through the glass column. Extensive tests including the removal characteristics, the removal efficiencies, and the metabolic products of NH3 by A. oxydans CH8 were conducted. Additionally, the operation criteria for the biofilter was also established. NH3 removal capacities were elevated by the immobilized-cell (biological conversion) method and the BDST (bed depth service time) method (physical adsorption), respectively. The optimum temperature for removing NH3 was 30 degrees C, while the nitrification ability remained 80% at 40 degrees C. The high efficiency (>97%) in the removal of NH3 was attained at 36 L/h with pH control and was not decreased because of high NH3 inlet concentration. In addition, the high maximum removal rate (1.22 g of N/day.(kg of bead)) enhanced the use of the biofilter in industrial-scale NH3(g) pollution control. The ability to remove NH3 at high inlet concentration and temperature suggested that the immobilized A. oxydans CH8 biofilter has potential in processing NH3 gas.