Browsing by Issue Date, starting with "1999-12-01"

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Authentication protocols for the broadband ISDN billing system
(1999-12-01)
Lo, CC
;
Yeh, YC
;
資訊管理與財務金融系註：原資管所+財金所
;
Department of Information Management and Finance
The broadband integrated services digital network (B-ISDN) offers a wide variety of services to its customers. From both provider's and user's perspective, a fair and flexible billing system is indispensable to the operation of B-ISDN. In this paper, we discuss different billing policies, and their corresponding authentication protocols, which can be used by the B-ISDN billing system. Flat rate and usage-based rate are two most frequently used billing policies. Because of the diversity of B-ISDN services, combining these two billing policies, along with priority pricing, is a feasible scheme for designing a B-ISDN billing system. The membership authentication protocol (MAP) and the personal authentication protocol (PAP) are proposed to support the authentication requirements of the flat rate and usage-based rate billing policies, respectively. The MAP applies the cipher block chaining (CBC) encryption in the two-party authentication protocol, while the PAP is a modified version of the station-to-station (STS) authentication protocol. Both protocols are designed in conjunction with a suggested key management method. Cryptanalysis shows that both the MAP and the PAP are very secure. Simulation results indicate that both protocols are efficient for providing mutual authentication. Together, these two protocols provide a good authentication mechanism to the B-ISDN billing system. (C) 1999 Elsevier Science B.V. All rights reserved.
Stability analysis and bounded sliding-mode control of a class of multi-input bilinear systems
(1999-12-01)
Chen, YP
;
Chang, JL
;
Lai, KM
;
電控工程研究所
;
Institute of Electrical and Control Engineering
A bounded sliding-mode controller is developed for a class of multi-input bilinear systems. The sliding vector design is based on the conventional pole-assignment method for linear time-invariant systems. Three conditions are required for the assigned eigenvalues when applying the pole-assignment method. A potential reaching-and-sliding region and a stable sliding region are determined around the origin, which is shown to be locally asymptotically stable. Numeric simulation results are used to demonstrate the success of the proposed bounded sliding-mode controller.
A genetic algorithm for the optimal design of microwave filters
(1999-12-01)
Hsu, HM
;
Tsai, SP
;
Wu, MC
;
Tzuang, CK
;
電信工程研究所
This paper presents a multiple objective genetic algorithm for determining the component parameters in the design of a microwave filter. In this approach, we first propose a set of fuzzy-based membership functions for modeling the five design specifications (objective functions) of the microwave filter design problem. The five objective functions are then aggregated into a single-valued fitness function. Finally, a set of near-optimal component parameters for the microwave filter can be found by applying the proposed genetic algorithm. A large number of experiments were performed and demonstrated satisfactory results. This approach has three principal merits. First, it counteracts entrapment in a local optimal solution. Second, the processing of multiple objectives is relatively easy. Third, the generated solution is independent of the initial estimate. Significance: This paper presents a multiple objective genetic algorithm for determining the component parameters in the design of a microwave filter.
On a problem of Dynkin
(1999-12-01)
Sheu, YC
;
應用數學系
;
Department of Applied Mathematics
Consider an (L, alpha)-superdiffusion X on R-d, where L is an uniformly elliptic differential operator in R-d, and 1 < alpha less than or equal to 2. The G-polar sets for X are subsets of R x R-d which have no intersection with the graph G of X, and they are related to the removable singularities for a corresponding nonlinear parabolic partial differential equation. Dynkin characterized the G-polarity of a general analytic set A subset of R x R-d in term of the Bessel capacity of A, and Sheu in term of the restricted Hausdorff dimension. In this paper we study in particular the G-polarity of sets of the form E x F, where E and F are two Borel subsets of R and R-d respectively. We establish a relationship between the restricted Hausdorff dimension of E x F and the usual Hausdorff dimensions of E and F. As an application, we obtain a criterion for G-polarity of E x F in terms of the Hausdorff dimensions of E and F, which also gives an answer to a problem proposed by Dynkin in the 1991 Wald Memorial Lectures.
管管作品六首
(1999-12-01)
管管
Embedding of any type of data in images based on a human visual model and multiple-based number conversion
(1999-12-01)
Wu, DC
;
Tsai, WH
;
資訊工程學系
;
Department of Computer Science
A novel approach to embedding any type of digital data into a cover image is proposed, which utilizes a human visual model to guarantee that the modification of the cover image is imperceptible. A quantized contrast function based on the model is constructed first. The gray values of each 3 x 3 sub-image of the cover image are used to compute, using the function, a range of gray levels with the same contrast as that of the central pixel of the sub-image. The embedding process proceeds by replacing the gray value of the central pixel by one of the values in the range. This guarantees that the changes be imperceptible. The data to be embedded is treated as a binary stream and is partitioned into a number of sub-streams. A multiple-base number conversion mechanism is used to convert each sub-stream of data into values which are then embedded in the central pixels of sub-images. The embedded data can be extracted out from the resulting stego-image without referencing the original image. Experimental results show that the proposed method is feasible. (C) 1999 Published by Elsevier Science B.V. All rights reserved.
管管作品六首
(1999-12-01)
管管
The block-based cycle time estimation algorithm for wafer fabrication factories
(1999-12-01)
Chung, SH
;
Huang, HW
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
Cycle time is both an important performance measure and requisite input data for performing production planning. However, the interactive effects between some factors such as process complexity and variety of workstations, leads to difficulty in estimating cycle time. To solve these problems, this study developed a block-based cycle time estimation algorithm, called BBCT, to estimate the total cycle time for each kind of wafer process. Process was divided into numerous blocks. The block cycle time is induced by batch and loading issues. The BBCT algorithm is used to derive the cycle time induced by the batch issue according to the process characteristics within each block. A queuing time model is used to derive the waiting time resulting from the loading issue. The simulation results show that the cycle time estimation performance is much improved by the BBCT algorithm. Significance: The proposed BBCT algorithm can improve the performance of cycle time estimation, and served as the basis for setting production targets.
New techniques on deformed image motion estimation and compensation
(1999-12-01)
Lin, CT
;
Wu, GD
;
Hsiao, SC
;
電控工程研究所
;
Institute of Electrical and Control Engineering
In this paper, new techniques for deformed image motion estimation and compensation using variable-size block-matching are proposed, which can be applied to an image sequence compression system or a moving object recognition system. The motion estimation and compensation techniques have been successfully applied in the area of image sequence coding. Many research papers on improving the performance of these techniques have been published; many directions are proposed, which can all lead to better performance than the conventional techniques. Among them, both generalized block-matching and variable-size block-matching are successfully applied in reducing the data rate of compensation error and motion information, respectively. These two algorithms have their merits, but suffer from their drawbacks. Moreover, reducing the data rate in compensation error is sometimes increasing the data rate in motion information, or vice versa, Based on these two algorithms, we propose and examine several algorithms which are effective in reducing the data rate. We then incorporate these algorithms into a system, in which they work together to overcome the disadvantages of individual and keep their merits at the same time, The proposed system can optimally balance the amount of data rate in tno aspects (i.e., compensation error and motion information), Experimental results show that the proposed system outweighs the conventional techniques. Since we propose a recovery operation which tries to recover the incorrect motion vectors from the global motion, this proposed system can also be applied for the moving object recognition in image sequence.
True near-field optical characters of a GaAlAs semiconductor laser diode
(1999-12-01)
Chen, SH
;
Tsai, DP
;
Chen, YF
;
Ong, PM
;
電子物理學系
In this research we have taken advantage of near-field scanning optical microscopy, a recently developed technique, to test the optical nature of GaAlAs semiconductor laser diodes working at 780 nm. With this method, both the images of the topographic and the near-field intensity of the laser diodes can be simultaneously obtained. With the obtained results, we can analyze the variety of the geometric structure, the local near-field optical intensity, the propagating modes, and the near-field mode-field diameter at different working states of the laser diodes. Hereby, we can find the factors that affected the radiation cavity of the laser diode and explore its alive state. (C) 1999 American Institute of Physics. [S0034-6748(99)01112-0].
管管作品六首
(1999-12-01)
管管
Non-reinitialized fully distributed power control algorithm
(1999-12-01)
Wang, JT
;
Lee, TH
;
電信工程研究所
;
Institute of Communications Engineering
A fully distributed power control (FDPC) algorithm has been recently proposed for cellular mobile systems. In the algorithm, the connection which has the smallest initial carrier-to-interference (CIR) ratio is removed if CIR requirements are not satisfied after L iterations of power control, The transmitter power levels of surviving connections are then reset to the maximal allowed values and the algorithm is executed again. We prove in this paper that, if the transmitter power levels are not reset after a connection is removed, then a feasible power set can be found faster and the power levels employed are smaller.
Kinetic study on epoxy bisphenol-A diacrylate IPN formation
(1999-12-01)
Lin, MS
;
Wang, MW
;
應用化學系
;
Department of Applied Chemistry
Interpenetrating polymer networks (IPN) based on diglycidyl ether of bisphenol-A (DGEBA) and bishenol-A diacrylate (BADA) in weight ratios of 100/0, 50/50, and 0/100 were blended and were cured simultaneously by using benzoyl peroxide (BPO) and 4,4'-methylenedianiline (MDA) as curing agents. Kinetic study during IPN formation was carried out at 65, 70, 75 and 80 degrees C. Absorbance changes at 1623.3 cm(-1) and 914 cm(-1) relating to concentration changes of C=C and epoxide were monitored with Fourier-transform infrared spectroscopy (FTIR). The epoxide cure kinetic data revealed a combination of non-catalytic bimolecular reaction and a catalyzed termolecular reaction, while the C=C cure kinetic data fitted a first-order reaction. The calculated kinetic parameters indicated decreased rate constants and increased activation energies of the IPN compared with those of the individual components. Presumably, chain entanglements between the two networks provide a sterically hindered environment for the cure reactions and vitrification restrains the chain mobility, accounting for the kinetic parameters. (C) 1999 Society of Chemical Industry.
Variations of X-ray spectrum in total reflection X-ray fluorescence (TXRF) analysis with respect to Si wafer crystal orientation for different incident angles
(1999-12-01)
Liou, BW
;
Lee, CL
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
This work studies the W-L-beta, Si-K-alpha and spurious radiations, which occur in the total reflection X-ray fluorescence (TXRF) analysis technique, Measurements at different azimuth angles were studied with respect to; the wafer orientation under different incident glancing angles of the X-ray beam on the surface of a bare Si-wafer, an oxide film, and an amorphous silicon film. It was found that both the W-LB radiation and the spurious radiation signals have a four fold periodic;variation with respect to the wafer orientation while the Si-K-alpha radiation signal does not have such a variation. For the oxide wafers, this periodic variation for the W-L-beta radiation and the spurious radiation signals becomes less and eventually disappears as the thickness of the oxide increases to 42 nm. For the amorphous silicon wafer, the above periodic variation phenomenon does not exist. This reveals that the W-L-beta and the:spurious radiation signals are mainly due to the interaction of incident X-ray evanescent radiation with the silicon crystal lattice. To reduce spurious signals in the TXRF analysis, a measurement at azimuth angle along the [100] directions of 45, 135, 225 or 315 degrees to the oxide-covered surface is suggested.
Performance enhancement of a joint transform correlator using the directionality of a spatial light modulator
(1999-12-01)
Hsieh, ML
;
Paek, EG
;
Wilson, CL
;
Hsu, KY
;
光電工程學系
We observe that conventional electrically addressable spatial light modulators have different transfer functions along the fast (horizontal) and the slow (vertical) directions. We then propose to use the directionality of a spatial light modulator to increase the performance of a joint transform correlator. Our experimental results show that input space-bandwidth product of a joint transform correlator can be significantly increased by recording a hologram so that interference fringes run along the fast (horizontal) direction of a spatial light modulator. (C) 1999 Society of Photo-Optical Instrumentation Engineers. [S0091-3286(99)00412-2].
Evolving complex robot behaviors
(1999-12-01)
Lee, WP
;
友訊交大聯合研發中心
;
D Link NCTU Joint Res Ctr
Building robots is a tough job because the designer has to predict the interactions between the robot and the environment as well as to deal with them. One solution to such difficulties in designing robots is to adopt learning methods. The evolution-based approach is a special method of machine learning and it has been advocated to automate the design of robots. Yet, the tasks achieved so far are fairly simple. In this work, we first analyze the difficulties of applying evolutionary approaches to synthesize robot controllers for complicated tasks, and then suggest an approach to resolve them. Instead of directly evolving a monolithic control system, we propose to decompose the overall task to fit in the behavior-based control architecture, and then to evolve the separate behavior modules and arbitrators using an evolutionary approach. Consequently, the job of defining fitness functions becomes more straightforward and the tasks easier to achieve. To assess the performance of the developed approach, we evolve a control system to achieve an application task of box-pushing as an example. Experimental results show the promise and efficiency of the presented approach. (C) 1999 Elsevier Science Inc. All rights reserved.
A vision-based method for the circle pose determination with a direct geometric interpretation
(1999-12-01)
Chen, Z
;
Huang, JB
;
資訊工程學系
;
Department of Computer Science
A novel vision-based method for the circle pose determination is addressed. This method is based on two particular projected chords of a circle image. The first one is the projection of a circle chord which subtends the largest apex angle of the viewing cone for the circle image and the second one is the projection of a circle diameter whose backprojection plane bisects the above largest apex angle. This method is conceptually simple, since the circle center is the center point of the diameter chord and the circle orientation is given by the cross product of these two (directed) chords. We present theorems on the geometry of both the viewing cone and a reprojected circle image which are essential to the pose determination. We then give a pose determination method which is applicable under all viewing conditions. Experimental results illustrate the good performance of the method, when compared with other existing methods.
Excitation of rotation collective modes in a vortex lattice of clean type-II superconductors
(1999-12-01)
Kasatkin, A
;
Rosenstein, B
;
電子物理學系
;
Department of Electrophysics
In a superclean limit the Magnus force on Abrikosov vortices is stronger than friction. Due to this, nondissipative force vortex segments rotate around pinning centers. Waves of such rotations under certain conditions are only weakly damped (not overdamped as is usually the case) and lead to resonances in the ac response. (The excitation of such waves by applied ac field near the-surface is considered. Surface impedance, ac resistivity, and magnetic permeability are calculated using elasticity theory of the vortex lattice. [S0163-1829(99)00442-7].
Arbitrarily shaped image coding by using translation invariant wavelet transforms
(1999-12-01)
Wu, BF
;
Su, CY
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This study presents two sets of translation invariant wavelet transforms for coding an arbitrarily shaped image. Each set can be viewed as a shape-adaptive discrete wavelet transform (SA-DWT) with the property of translation invariance. The proposed transform schemes have the following merits: (1) they are translation invariant, (2) no sharp transition appears at the edges of the image, (3) the number of pixels is maintained constant after transformation, (4) the correlation of pixels is fully exploited, and (5) the property of self-similarity across scales is preserved. (C) 1999 Elsevier Science B.V. All rights reserved.
Evaluation of metal migration and determination of trace metals after microwave digestion for lithographic materials
(1999-12-01)
Ko, FH
;
Wang, MY
;
Wang, TK
;
奈米中心
;
Nano Facility Center
The radioactive tracer technique was applied to investigate the migration of cesium and zinc impurities from bottom antireflective coating (BARC) and photoresist (PR) into underlying substrate. The effects of normal baking temperatures and substrate types were studied. Our results indicated that BARC has higher migration ratios than PR, irrespective of the substrate types and normal baking temperatures. The substrate type did not appear to strongly affect the metal migration ratios. However, water and/or solvent evaporation due to temperature change was found to have a significant effect on metal migration. The diffusion profiles of BARC and PR were depicted based on diffusion equations and the migration ratios. Both the UV/visible spectrometric and the gravimetric methods were successfully implemented to evaluate the feasibility of closed-vessel microwave digestion efficiency for BARC and PR samples. By following the established microwave digestion method and the inductively coupled plasma mass spectrometer (ICPMS) determination, the detection limits obtained for multielements were in the ppb and sub-ppb levels. Except for calcium, the spike recoveries of metals ranged from 91 to 132% and 87 to 125% for BARC and PR, respectively. The analytical results were found to be in reasonably good agreement with the Literature values.