Browsing by Issue Date, starting with "1995-02-28"

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FINITE MATRIX COMPUTATIONS APPLIED TO THE SCATTERING OF A WAVEPACKET IN THE COULOMB POTENTIAL
(1995-02-28)
PEN, UL
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JIANG, TF
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物理研究所
;
Institute of Physics
We develop a finite dimensional matrix method to treat wavepacket propagation in potential scattering problems. The method is useful for general quantum mechanical problems. The scattering dynamics of a minimum uncertainty wavepacket in the Coulomb potential is presented.
LIQUID-PHASE BONDING OF YTTRIA-STABILIZED ZIRCONIA WITH CAO-TIO2-SIO2 GLASS
(1995-03-01)
CHIOU, BS
;
YOUNG, CD
;
DUH, JG
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A 36.8wt % CaO-26.2 wt % TiO2-37.0 wt % SiO2 glass (CTS) was employed as the ceramic brazer for the bonding of 3 mol % yttria stabilized zirconia (YSZ3). Sandwich-like YSZ3-CTS-YSZ3 specimens were fabricated and temperature dependence of the bonding strength was evaluated. An optimum bonding process was achieved at a bonding temperature of 1424 degrees C for 30 min with CTS glass slurry having a glass/organic ratio of 1.82. The effects of processing parameters on the bending was investigated on the basis of the metallurgical evolution at the interface. In addition, predominating factors affecting the bonding strength were also explored.
ORIENTATION OF THE NI MAGNETIC-MOMENTS IN NI-ZN FERRITES
(1995-03-01)
PONG, WF
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CHANG, YK
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SU, MH
;
LIN, HJ
;
HO, GH
We report the Ni L(2,3)-edges magnetic circular dichroism measurements of the ZnxNi1-xFe2O4 (x = 0.0, 0.26, 0.50, and 0.75) ferrimagnet. The Ni average magnetic moments were found to decrease significantly with increasing Zn content. This observation is interpreted in terms of the Yafet-Kittel type canting of the Ni magnetic moment and shows values greater than those of the Fe magnetic moment determined from Mossbauer and neutron diffraction measurements. This work provides new information on the effect of Zn doping of Ni-O-Ni and Fe-O-Fe superexchange couplings.
SIMPLE ANALYTICAL METHOD OF CAVITY DESIGN FOR ASTIGMATISM-COMPENSATED KERR-LENS MODE-LOCKED RING LASERS AND ITS APPLICATIONS
(1995-03-01)
LIN, KH
;
LAI, YC
;
HSIEH, WF
;
交大名義發表
;
光電工程學系
An analytical method based on a renormalized q parameter for Gaussian-beam propagation and properly matched self-consistent complex q parameters is proposed to aid in the design of arbitrary-astigmatism-compensated Kerr-lens mode-locked ring cavity lasers. The q parameters throughout the ring cavity can be calculated by solution of an algebraically quadratic equation for an arbitrarily thick Kerr medium when the intracavity laser power is less than the self-trapping power. The Kerr-lens mode-locking strength at the curved mirror was calculated over the stable range. The results indicate that the astigmatism is best compensated so that the stable range of x and y directions have optimal overlapping. Although to maximize the hard-aperturing effect the curved mirror separation must be at the far edge of the stable range, pump and cavity field matching inside the Kerr medium is also necessary. In addition, the insertion of a vertical slit is more effective than insertion of a horizontal slit. A spiking phenomenon is found in the intracavity z scan curve, which can be observed only with thick Kerr materials and a high laser power.
NEURO-FUZZY MODELING AND CONTROL
(1995-03-01)
JANG, JSR
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SUN, CT
;
資訊工程學系
;
Department of Computer Science
Fundamental and advanced developments in neuro-fuzzy synergisms for modeling and control are reviewed. The essential part of neuro-fuzzy synergisms comes from a common framework called adaptive networks, which unifies both neural networks and fuzzy models. The fuzzy models under the framework of adaptive networks is called Adaptive-Network-based Fuzzy Inference System (ANFIS), which possess certain advantages over neural networks. We introduce the design methods for ANFIS in both modeling and control applications. Current problems and future directions for neuro-fuzzy approaches are also addressed.
TRANSFER-FUNCTION BETWEEN WAVE HEIGHT AND WAVE PRESSURE FOR PROGRESSIVE WAVES - REPLY
(1995-03-01)
KUO, YY
;
CHIU, JF
;
交大名義發表
;
土木工程學系
;
National Chiao Tung University
Modification of Mononobe-Okabe theory
(1995-03-01)
Fang, YS
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Chen, TJ
;
交大名義發表
;
National Chiao Tung University
GENERALIZED MINIMAL DISTORTION SEGMENTATION FOR ANN-BASED SPEECH RECOGNITION
(1995-03-01)
CHEN, SH
;
CHEN, WY
;
交大名義發表
;
電信工程研究所
;
National Chiao Tung University
A generalized minimal distortion segmentation algorithm is proposed to solve the time alignment problem for ANN-based speech recognition. By modeling dynamics of spectral information of an acoustic segment with smooth curves obtained by orthonormal polynomial expansion, a speech signal is optimally divided into segments and then recognized by an MLP recognizer. Experimental results showed that the proposed method outperforms the standard CDHMM method.
ON THE CONVERGENCE OF THE L(P)-NORM ALGORITHM FOR POLYNOMIAL PERCEPTRON HAVING DIFFERENT ERROR SIGNAL DISTRIBUTIONS
(1995-03-01)
CHANG, CH
;
SIU, S
;
WEI, CH
;
電控工程研究所
;
Institute of Electrical and Control Engineering
The convergence property of the l(p)-norm algorithm for polynomial-perceptron having different error signal distributions will be analyzed in this paper. To see the effect of error signal on the convergence rate, two types of activation functions are considered in the analysis: one is of a linear type and the other is of a sigmoidal type. Different activation functions yield different ranges of output signal and, in turn, yield different error signal distributions. Linear activation function causes the error signal to be distributed in an uncertain way, while sigmoidal activation function causes it to be distributed in a tightly bounded region. Based on this difference the convergence property of the l(p)-norm algorithm, 1 less than or equal to p less than or equal to 2, is investigated in this paper. Expressions of average learning gains are obtained in terms of the power metric p, the error probability, and the upper bound bf the error signal distribution. Analytic results indicate that it is of particular value in using the l(p)-norm algorithm for the perceptron using sigmoidal activation functions. Computer simulation of an adaptive equalizer using this algorithm confirms the theoretical analysis.
A WORST-CASE OF CIRCULARITY TEST ALGORITHMS FOR ATTRIBUTE GRAMMARS
(1995-03-01)
WU, PC
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WANG, FJ
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交大名義發表
;
資訊工程學系
;
National Chiao Tung University
Although the circularity test problem for attribute grammars (AGs) has been proven to be intrinsically exponential, to date, a worst case for the existing circularity test algorithms has yet to be presented. This note presents a worst-case AG in which the number of incomparable dependency graphs induced at the root is exponential. The worst case can help to clarify the complexity of the problem.
LATERAL TITANIUM SILICIDE GROWTH AND ITS SUPPRESSION USING THE A-SI/TI BILAYER STRUCTURE
(1995-03-01)
LOU, YS
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WU, CY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The effects of internal oxygen impurities released from the TiSiO2 reaction on the lateral silicide growth using the a-Si/Ti bilayer structure are presented. The lateral silicide growth can be effectively retarded by internal oxygen impurities using a-Si/Ti bilayer process after silicidation at a temperature below 700 degrees C. Compared with the simultaneously processed single Ti layer process, it is observed that both high-level oxygen impurities and their redistribution in the possible Si-diffusion paths play the same important role on the suppression of the lateral silicide growth. Finally, the oxygen redistribution-dependent kinetics is developed to give a self-consistent explanation fo; the experimental observations from both the single Ti layer process and the a-Si/Ti bilayer process.
PULSE BUILDUP DYNAMICS OF AN ACTIVELY MODE-LOCKED LASER-DIODE ARRAY IN THE EXTERNAL-CAVITY
(1995-03-01)
WANG, CL
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KUO, JC
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CHANG, CS
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PAN, CL
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交大名義發表
Dynamic pulse evolution characteristics of an actively mode-locked laser diode array in the external cavity have been investigated, Numerical calculations based on modified traveling-wave rate equations reproduce experimentally observed pulse and spectral width evolution and show that the buildup time is about 45 round-trips, We have also performed a theoretical analysis to understand which of the laser operating parameters would affect the buildup dynamics, It is shown that either higher de bias current or larger radiative recombination coefficient (which is inversely proportional to the excited-state lifetime) will render the laser exhibiting shorter steady-state pulse width and faster evolution to the steady state, Other parameters affecting the buildup, but to a lesser extent, include the radio-frequency (RF) modulation current, spontaneous emission coefficient, and gain coefficient, The power reflectivities of the output mirror and the antireflection coated diode facet, on the other hand, have little effect on the pulse width and buildup time for single pulse generation.
ORIENTATION ASSIGNMENT OF STANDARD CELLS USING A FUZZY MATHEMATICAL TRANSFORMATION
(1995-03-01)
YAN, JT
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HSIAO, PY
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資訊工程學系
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Department of Computer Science
It is well known that minimising total wire length reduces routing area in a standard cell layout. After the placement phase, another advanced improvement on total wire length is made by assigning the orientations of standard cells. In the paper, based on fuzzy c-means clustering, the authors develop two-way constrained fuzzy graph clustering and the transformation between the orientation assignment of standard cells and the constrained graph bisection to minimise total wire length. Finally, the proposed algorithm has tested several standard cell layouts, and the experimental results show that the proposed algorithm produces significant wire reduction on total wire length.
AN OPTIMAL INSTRUCTION SCHEDULER FOR SUPERSCALAR PROCESSOR
(1995-03-01)
CHOU, HC
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CHUNG, CP
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交大名義發表
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資訊科學與工程研究所
;
National Chiao Tung University
Performance in superscalar processing strongly depends on the compiler's ability to generate codes that can be executed by hardware in an optimal or near optimal order, Generating optimal code is an NP-complete problem. However, there is a need for highly optimized code, such as in superscalar or real-time systems, In this paper, an instruction scheduling scheme for optimizing a program trace is proposed. Optimized code can be arrived at without much redundant work, if some important features in code are well explored and utilized in scheduling. To formalize the task, two abstract models, one for a superscalar processor and the other for a program trace, are given, These two models reflect most of the characteristics of the scheduling problem. The interrelations between instructions and partial schedules are thoroughly studied, and dominance and equivalence relations on them are defined, These relations are then used to reduce the solution space and eventually help to produce optimal schedules. The results of experiments that show the promise of the proposed scheme are also presented.
FACE SELECTIVITY IN THE PATERNO-BUCHI REACTIONS OF METHACRYLONITRILE TO 5-SUBSTITUTED ADAMANTAN-2-ONES
(1995-03-01)
CHUNG, WS
;
LIU, YD
;
WANG, NJ
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交大名義發表
;
應用化學系
The photocycloaddition of methacrylonitrile to 5-substituted adamantan-2-ones (1-X) produces two geometrically isomeric oxetanes in which the oxygen atom and the 5-substituent are in anti or syn positions. The substituent was varied from fluoro, chloro, bromo, phenyl to SiMe(3) and the product ratios, except for SiMe(3), were similar (ca. 56:44) in all instances. Structure determination of the anti and syn oxetanes were carried out by H-1 and C-13 NMR and mass spectroscopy. The structure of syn-5-bromospiro[adamantane-2,2'-oxetane] (syn-5-Br) was further supported by single-crystal X-ray crystallography. The product formation bias resulting from the attack on the zu-face is discussed in terms of transition-state hyperconjugation, but new results for photocycloaddition reactions of 5-trimethylsilyl-substituted adamantan-2-one (1-SiMe(3)), with both fumaronitrile and methacrylonitrile, show an unprecedented sigma-electron-withdrawing characteristic with this substituent.
EFFECTS OF COBALT SILICIDATION ON THE ELECTRICAL CHARACTERISTICS OF SHALLOW P(+)N JUNCTIONS FORMED BY BF2+ IMPLANTATION INTO THIN POLYCRYSTALLINE SI FILMS
(1995-03-01)
LIN, CT
;
CHAO, CH
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JUANG, MH
;
JAN, ST
;
CHOU, PF
Excellent shallow p(+)n junctions have been formed by implanting BF2+ ions into thin polycrystalline Si films and subsequent annealing. The samples implanted at 50 keV to a dose 5 x 10(15) cm(-2) show a leakage of 1 nA/cm(2) and a junction depth of about 0.05 mu m after a 800 degrees C annealing. To reduce the series resistances of the junctions, silicidation with different col;alt thickness was used to drive the as-implanted dopants in the polysilicon films into the resultant junctions of the silicon substrates. For the low energy implantation at 50 keV at all dosages, silicidation can result in poor electrical characteristics due to the confinement of the dopants by the silicidation process. On the other hand, the electrical characteristics can be retained when a higher implantation energy of 100 keV with a dosage higher than 5 x 10(15) cm 2 was used. In addition, the samples implanted at 125 keV show poor electrical characteristics for the nonsilicided junctions but good characteristics after the silicidation. It is attributed to the enhanced defect annihilation by the formed silicide. Furthermore, silicided implanted through poly-Si junctions with excellent characteristics can be fabricated after a low temperature (600 degrees C) annealing if the samples are implanted at 100 keV with a dosage higher than 5 X 10(15) cm(-2).
THE DESIGN OF A CAPACITY REQUIREMENTS PLANNING SYSTEM FOR FLEXIBLE MANUFACTURING SYSTEMS
(1995-03-01)
CHUNG, SH
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交大名義發表
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工業工程與管理學系
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National Chiao Tung University
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Department of Industrial Engineering and Management
The operating and manufacturing characteristics of a flexible manufacturing system (FMS) mean that a traditional planning procedure of material requirements planning (MRP) and capacity requirements planning (CRP) cannot be followed. Thus the planning works between the master production schedule and the shop-floor control (SFC) systems are analysed and reassigned to the MRP, CRP and SFC systems. A CRP system designed for FMS is presented in this paper. It determines the requested capacities by carrying out part type selection, batch size determination and process plan selection, and by estimting tool slot requests. If there is insufficient capacity, the CRP system calculates the overtime hours required to complete the production of demand quantity for a specified part type.
AN EFFICIENT METHOD FOR UNCONSTRAINED OPTIMIZATION PROBLEMS OF NONLINEAR LARGE MESH-INTERCONNECTED SYSTEMS
(1995-03-01)
LIN, SY
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LIN, CH
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交大名義發表
;
電控工程研究所
;
National Chiao Tung University
We present a new efficient method for solving unconstrained optimization problems for nonlinear large mesh-interconnected systems. This method combines an approximate scaled gradient method with a block Gauss-Seidel with line search method which is used to obtain an approximate solution of the unconstrained quadratic programming subproblem. We prove that our method is globally convergent and demonstrate by several numerical examples its superior efficiency compared to a sparse matrix technique based method. In an example of a system of more than 200 variables, we observe that our method is 3.45 times faster than the sparse matrix technique based Newton-like method and about 50 times faster than the Newton-like method without the sparse matrix technique.
LQC/LTR CONTROL OF AN AC INDUCTION SERVO DRIVE
(1995-03-01)
TZOU, YY
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WU, HJ
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交大名義發表
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電控工程研究所
;
National Chiao Tung University
A new design method based on the linear-quadratic-Gaussian with loop-transfer-recovery (LQG/LTR) theory has been developed for the design of high performance ac induction servo drives using microcomputer-based digital control, The principle of field orientation is employed to achieve the current decoupling control of an induction motor. An equivalent model representing the dynamics of the decoupled induction motor has been developed, Based on the developed model with specified parameter uncertainties and given performance specifications, a frequency domain loop-gain-shaping method based on the LQG/LTR theory is proposed for the design of the servo loop controller. A microcomputer-based induction servo drive has been constructed to verify the proposed control scheme. Simulation and experimental results are given to illustrate the effectiveness of the proposed design method.
CROSSOVER PHENOMENON IN OXIDATION RATES OF THE (110) AND (111) ORIENTATIONS OF SILICON IN N2O
(1995-03-01)
CHAO, TS
;
LEI, TF
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電控工程研究所
;
Institute of Electrical and Control Engineering
Growth mechanisms of three different orientations Si wafer oxidized in N2O have been investigated in this study. A thickness crossover phenomenon in oxidation rates was found for orientations (110) and (111) at a critical oxide thickness 150 Angstrom. From our results, this phenomenon is closely related with the initial native oxide before oxidation.