Browsing by Issue Date, starting with "1993-04-28"

Now showing 1 - 20 of 89665

(S, R, MU)-NETS AND ALTERNATING FORMS GRAPHS
(1993-04-28)
HUANG, TY
;
LAURENT, M
;
應用數學系
;
Department of Applied Mathematics
WDM/FDM STAR COUPLER WITH GAIN USING FIBER AMPLIFIERS
(1993-04-29)
CHEN, YK
;
CHI, S
;
光電工程學系
;
電信研究中心
;
Department of Photonics
An efficient amplified WDM/FDM star coupler is proposed. The size of the coupler can be increased by a factor of m using m fibre amplifiers. Furthermore, the complexity and cost of the proposed scheme are less than those of other configurations.
THE TOWERS OF HANOI PROBLEM WITH CYCLIC PARALLEL MOVES
(1993-04-29)
WU, JS
;
CHEN, RJ
;
交大名義發表
;
資訊工程學系
;
National Chiao Tung University
This paper discusses a variant of the towers of Hanoi problem with cyclic parallel moves. We propose an algorithm for this problem and show that the algorithm is optimal.
SAMPLE BUFFER - A PROGRESSIVE REFINEMENT RAY-CASTING ALGORITHM FOR VOLUME RENDERING
(1993-05-01)
KE, HR
;
CHANG, RC
;
資訊工程學系
;
Department of Computer Science
Ray-casting has been shown to be an excellent technique for rendering volume data. This paper describes a new ray-casting algorithm that employs the concept of progressive refinement for volume rendering. Volume data are embedded into a complete octree, and when the volume data are rendered, the octree is traversed according to a user-defined threshold. By reducing this threshold gradually, we can render increasingly refined images. Ray-casting is used to explore the octree, and a data structure called a sample buffer (SB) is introduced to reduce the time required to render a series of images. With this method, a satisfactory balance between image quality and computation time can be achieved.
DATA ENVELOPMENT ANALYSIS IN MEASURING THE EFFICIENCY OF FOREST MANAGEMENT
(1993-05-01)
KAO, C
;
CHANG, PL
;
HWANG, SN
;
管理科學系
;
Department of Management Science
管管簡介
(1993-05-01)
管管
OPTIMAL TILE PARTITION FOR SPACE REGION OF INTEGRATED-CIRCUITS GEOMETRY
(1993-05-01)
HSIAO, PY
;
LIN, CY
;
SHEW, PW
;
資訊工程學系
;
Department of Computer Science
An optimal tile partition (OTP) is presented for partitioning the space region of a VLSI layout plane into rectangular space tiles. It modifies the corner stitching data structure to optimise the space tile partition. There is a serious restriction in the original corner stitching data structure, i.e. the solid rectangles cannot overlap each other, whereas our OTP allows overlapping. This paper also shows three theorems with rigorous proofs and experimental results to obtain the minimal number of the space tiles through the OTP. Moreover, a dynamic plane-sweep algorithm based on region query for the OTP has been developed. Using the OTP, the memory efficiency and the local query operations of the original corner stitching data structure have been enhanced.
ANALYTIC-FUNCTIONS FOR ATOMIC MOMENTUM-DENSITY DISTRIBUTIONS AND COMPTON PROFILES OF K-SHELLS AND L-SHELLS
(1993-05-01)
CHEN, YF
;
KWEI, CM
;
TUNG, CJ
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
An analytical expression involving three parameters was proposed for atomic momentum-density distributions of K and L shells. This expression was based on the superposition of hydrogenic closed-shell momentum densities. Parameters in the expression were determined by requiring four of its moments to be equal to the corresponding Hartree-Fock results. An analytical function for the Compton profiles was then derived using the impulse approximation. Excellent agreement was found between the present results and detailed theoretical computations.
SUPERCONDUCTING PROPERTIES OF ORIENTED YBA2CU3O7-X FILMS ON MGO AND SRTIO3 SUBSTRATES
(1993-05-01)
HAUNG, CJ
;
TSENG, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Using single-target sputter deposition, the c-axis oriented YBa2Cu3O7-x films can be obtained on both MgO and SrTiO3 substrates by appropriately controlling the substrate temperature at 700-degrees-C. However, on examining a.c. susceptibility and electrical dissipation, we find that the films on a SrTiO3 substrate possess better superconducting properties, such as a stronger coupling between the superconducting grains; a higher potential energy for flux pinning; and a larger capacity for current conduction. Also, from the magnetization hysteresis measurement, the critical current density of 2.6 x 10(6) A cm-2 (77 K) and 4.5 x 10(7) A cm-2 (5 K) for the sample on the SrTiO3 substrate can be estimated.
DEVELOPMENT OF OSCILLATORY ASYMMETRIC RECIRCULATING FLOW IN TRANSIENT LAMINAR OPPOSING MIXED CONVECTION IN A SYMMETRICALLY HEATED VERTICAL CHANNEL
(1993-05-01)
LIN, TF
;
CHANG, TS
;
CHEN, YF
;
交大名義發表
;
機械工程學系
Detailed flow and thermal characteristics in transient laminar opposing mixed convection in a vertical plane channel subject to a symmetric heat input are numerically investigated. First, a linear stability analysis was employed to evidence the occurrence of flow bifurcation. Then, the unsteady Navier-Stokes equations along with the continuity and energy equations were respectively integrated by a third-order upwind and power-law finite-difference scheme with the resulting matrices inverted by the Fast Fourier Transform and conjugated gradient methods. Reverse flow in the form of symmetric, elongated recirculating cells is initiated earlier and is stronger in a lower Prandtl number fluid with higher opposing buoyancy and Reynolds number and longer heated section length. A t a high opposing buoyancy, sudden flow asymmetry and oscillation occur simultaneously in a nearly steady flow after the initial transient. Periodic flow and thermal evolution are noted in space and time. An empirical equation for the condition for inducing flow oscillation is proposed.
POLYHEDRAL FACE RECONSTRUCTION AND MODELING FROM A SINGLE IMAGE WITH STRUCTURED LIGHT
(1993-05-01)
CHEN, Z
;
HO, SY
;
TSENG, DC
;
資訊工程學系
;
Department of Computer Science
The determination of the 3-D geometric model of visible polyhedral faces from a single view is addressed. It applies a grid coding technique to derive the normal vector of each visible polyhedral face and the depth parameter of the race equation based on the given dimensions of the grid on the code plate. It is shown that the method is correspondenceless. Furthermore, it also determines the 3-D face model for all visible polyhedral faces including the occlusion relations between faces. Two edge reconstruction methods are given and their goodness are compared. For the determination of the final object model, three different integration methods are given. Some experiments are reported to illustrate the method.
ORIENTATION RELATIONSHIPS BETWEEN M2C CARBIDE AND THE AUSTENITE MATRIX IN AN FE-MN-AL-MO-C ALLOY
(1993-05-01)
PENG, SW
;
CHOU, CP
;
交大名義發表
;
機械工程學系
;
National Chiao Tung University
M2C carbides were observed to precipitate within the austenite matrix of an Fe-24-6Mn-6.6Al-3.1Mo-1.0C alloy after quenching from 1200-degrees-C and aging at 750-degrees-C. By means of transmission electron microscopy (TEM) and diffraction techniques, the orientation relationships between M2C (p) and the austenite (gamma) matrix were determined to be: (0001)p//(111)gamma, (1120BAR)p//(110BAR)gamma, (1100BAR)p//(112BAR)gamma. M2C carbide has been reported by many researchers to precipitate from the ferrite matrix or along austenite/ferrite boundaries in alloy steels containing Mo. However, little information concerning the formation of M2C in the austenite matrix has been provided. This investigation presents the first evidence for the existence of M2C carbide wholly within the austenite matrix and its relationship to the austenite. The energy-dispersive spectrometry (EDS) analyses were performed on M2C carbides, and the results indicate that the solubility of the M2C carbide for foreign atoms other than Mo is very limited.
AN EFFECTIVE SEARCH APPROACH TO CAMERA PARAMETER-ESTIMATION USING AN ARBITRARY PLANAR CALIBRATION OBJECT
(1993-05-01)
CHEN, Z
;
WANG, CM
;
HO, SY
;
交大名義發表
;
資訊科學與工程研究所
In this paper we shall present a new method for camera parameter estimation using an arbitrary planar calibration object. We begin with an approximate model for the perspective view and give a parameter-free normalized-line-segment-ratio relationship between the corresponding reference and sensed views. This representation makes parameter decoupling possible and reduces the library dimension from six to one. Then the estimation problem can be viewed as a library search problem. Various mechanisms are provided to reduce the library search time, including (a) library partition by clustering, (b) sensed cluster identification by binary search, and (c) sequential testing for view matching using sorted features. In addition, feature perturbation is also considered to achieve better robustness against feature noise. Both computer-generated and real data are included in experiments, illustrating how our method works.
OPTICAL-PATTERN SIMULATIONS FOR CLOSED CYLINDERS OF LIQUID-CRYSTALS
(1993-05-01)
LIANG, BJ
;
WEI, JG
;
CHEN, SH
;
光電工程學系
;
Department of Photonics
Optical patterns for the polarizing microscope textures of closed cylinders of liquid crystals (CCLCs) are studied by the Jones vector formulation. The simulated director configuration diagram of a CCLC with normal orientation at the walls contains four kinds of stable director configurations. The resulting texture under some approximations depends only on phase shifts. The patterns are characterized by dark brushes that coincide with the directions of the crossed polarizers. Additionally, there are concentric circle fringes. For the ring defect structure, the centre region of the cylinder exhibits a black extinction. However, this is not distinguishable as between the hyperbolic and radial structures for both the point and the ring defect patterns. Comparing the observed patterns with the simulated ones, we find that the dark cross brushes and the centre black extinction of simulated patterns are similar to those that are observed. However, the concentric circle fringes of the observed pattern are not in accordance with the simulated pattern.
EVALUATION OF INSITU FORMED W-TI AND MOSI2 AS A DIFFUSION BARRIER TO AL FOR COSI2 SILICIDED CONTACT
(1993-05-01)
YANG, FM
;
CHEN, MC
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A simple metallization process to form a shallow CoSi2 silicided contact and W-Ti diffusion barrier simultaneously has been developed. The process starts with depositions of a Co-Ti alloy layer and an overlying W layer on silicon wafers using a dual e-beam evaporation system; this is followed by a single-step annealing treatment in a normal flowing-nitrogen furnace. On the other hand, bilayer self-aligned shallow MoSi2/CoSi2/Si silicided contact can be derived from the W/Co-Mo/Si system by a two-step annealing treatment performed in the same environment. I-V characteristics for silicided p+n diodes with the diffusion barriers formed in situ were measured after they had been finished with Al deposition and post-Al annealing at temperatures from 350 to 600-degrees-C in N2. For comparison, Al/CoSi2/p+n and Al/p+n structures were also investigated. It turns out that the integrity of Al/W-Ti/CoSi2/P+n and Al/MoSi2/COSi2/P+ n silicided contacts can be preserved up to 5 50 and 500-degrees-C, respectively, for a 20 min annealing, while that of Al/CoSi2/P+n can be kept only up to 450-degrees-C.
MULTIOBJECTIVE DECISION-MAKING FOR TRAFFIC ASSIGNMENT
(1993-05-01)
TZENG, GH
;
CHEN, CH
;
運輸與物流管理系註：原交通所+運管所
;
Department of Transportation and Logistics Management
In traditional traffic-assignment problems, only a single objective is considered. Although people's living quality improves and transportation needs increase, the environmental quality is destroyed with rapid economic and traffic growth. The concept of traffic assignment, an important procedure for transportation planning, should take all needs into consideration. Based on the viewpoints of all constituencies, this paper attempts to determine optimal flow patterns using three objectives-total travel time for road users, air pollution for nonusers (such as community residents), and travel distance for government-to formulate an effective multiobjective model for traffic assignment. By using multiobjective decision making and nonlinear programming techniques, a series of noninferior solutions is generated. By combining an eigenvector weighting method with pairwise comparison, we obtain a compromise solution for the flow pattern. An application case for the Taipei network system is also presented and discussed. The results show that if other nontraffic related factors are taken into account, the multiobjective traffic-assignment approach is more reasonable and suitable than conventional approaches.
THE STUDY OF WAVE PRESSURE AND UPLIFT FORCE ON A SUBMERGED PLATE
(1993-05-01)
YUEH, CY
;
KUO, YY
;
土木工程學系
;
Department of Civil Engineering
Boundary element method (BEM) is used to study wave pressure acting on a vertical quay, as well as the uplift forces on a submerged plate. The plate, placed in front of the quay, is bored with holes. The results are then compared with the case of a plate without any perforation. The results showed that: for q/h = 0.45, where q is the depth of submergence of the plate and h is water depth, wave pressure acting on the vertical quay is very similar for plates with or without borings. However, with q/h = 0.20, wave pressure on the quay is changed according to wave periods, widths of the plate, the distance of the plate away from the quay, as well as the ratio of the holes to the plate. Uplift forces exerted on the plate are indeed smaller for plates with borings than without, and decrease with increasing porous ratio. Furthermore, the uplift forces will be the same for the same porous ratios, regardless of these ratios being caused by a single or a double perforation.
OPTIMAL FRAME PATTERN DESIGN FOR A TDMA MOBILE COMMUNICATION-SYSTEM USING A SIMULATED ANNEALING ALGORITHM
(1993-05-01)
CHANG, CJ
;
WU, CH
;
電信工程研究所
;
電信研究中心
;
Institute of Communications Engineering
Different relative Positions of voice and data slots within the frame of a TDMA mobile communication system may result in different system data throughput. The optimal relative position, namely the frame pattern which can achieve maximum data throughput, is designed in this paper. This design method can be formulated as solving a combinatorial optimization problem. Generally, the global optimal solution of such a problem is hard to find using conventional methods, which may be computationally intractable. A reliable and effective method called a simulated annealing algorithm is applied to obtaining the global optimum. Numerical results reveal that there exist various optimal frame patterns for different ranges of traffic load and the optimal frame pattern can achieve great throughput improvement over a random frame pattern.
THE COMPUTER-SIMULATION AND EXPERIMENTAL-ANALYSIS OF CHIP MONITORING FOR DEEP HOLE DRILLING
(1993-05-01)
CHIN, JH
;
WU, JS
;
YOUNG, RS
;
交大名義發表
;
機械工程學系
Chip congestion is a long time bottleneck in deep hole drilling. This paper addresses the problem of chip state monitoring in single-edge deep hole drilling by computer simulation and experimental analysis. Two phenomenological models were proposed to interpret the physics of chip discharging in normal and congested states, respectively. Length and diameter of the chip are chosen to represent the geometric features of the chip, and the formation of a chip signal is discussed. Based on the two models different types of chips are used to simulate the monitoring process. Computer simulation shows that the normal chip discharging in a real drilling process can be interpreted by the proposed slug flow model. Also, the experiments with cylindrical form chips confirms model II proposed for a congested chip state in which the diametral effect develops due to chip congestion. The experimental analyses also find out the dependence of pressure signals on the various parameters of chips as well as the cutting process.
管管簡介
(1993-05-01)
管管