Browsing by Issue Date, starting with "1999-08-17"

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Analysis of a general limited scheduling mechanism for a distributed communication system
(1999-08-17)
Hwang, LC
;
Chang, CJ
;
電信工程研究所
;
電信研究中心
;
Institute of Communications Engineering
This paper studies an alternative scheduling mechanism of general limited service discipline for a distributed communication system, where the distributed system has a modular architecture and the module has tasks in the queue. We successfully analyze the system by way of imbedded Markov chains acid use a recursive method to derive the mean waiting time of task. The arrival processes for modules are assumed to be Poisson processes; the service time of a task in queues and the walking time between queues are assumed to be generally distributed. We also presents an optimal-pattern design of the general limited scheduling mechanism for the distributed communication system via a genetic algorithm. A distributed communication system, if designed with the general limited scheduling mechanism and its optimal pattern, can be flexible to meet the system requirements as much as possible. (C) 1999 Elsevier Science B.V. All rights reserved.
Tunable semiconductor laser with liquid crystal pixel mirror in grating-loaded external cavity
(1999-08-19)
Pan, CL
;
Tsai, SH
;
Pan, RP
;
Sheu, CR
;
Wang, SC
The wavelength of a commercial red pointer laser diode has been tuned over 4nm digitally in 0.2nm steps with a folded telescopic gating loaded external cavity incorporating a liquid crystal pixel mirror. The sidemode-suppression ratio of the laser was better than 20dB throughout this range.
PP/PA6 blends compatibilized by poly(oxypropylene)amide-functionalized PP.
(1999-08-22)
Lin, JJ
;
Young, MY
;
Tseng, FP
;
Chang, FC
;
應用化學系
Synthesis of elvirol methyl ether.
(1999-08-22)
Ho, TL
;
Ho, MF
;
應用化學系
;
Department of Applied Chemistry
Preparation and epoxy curing of novel Mannich bases.
(1999-08-22)
Lin, JJ
;
Lin, SF
;
Tseng, FP
;
Chang, FC
;
應用化學系
Observation of abnormal capacitance-frequency behavior in In0.12Ga0.88As/GaAs p-i-n superlattice grown at low temperature
(1999-08-23)
Chen, JF
;
Wang, JS
;
Wang, PY
;
Wong, HZ
;
電子物理學系
Capacitance-frequency measurement is used to study In0.12Ga0.88As/GaAs p-i-n superlattice, with superlattice layer grown at 300 degrees C by molecular-beam epitaxy. Three traps are observed, and their parameters are consistent with those obtained from deep-level transient spectroscopy. Among these three traps, the trap (E-a = 0.45 +/- 0.02 eV, sigma = 6 +/- 4x10(-17) cm(2)) shows an abnormal increase of capacitance with increasing frequency, similar to that observed from the 0.66 eV trap in low-temperature grown GaAs p-i-n structure, suggesting that it is created by the low-temperature growth and is a generation-recombination center. This result also shows that the capacitance-frequency measurement is effective in studying the generation-recombination centers. (C) 1999 American Institute of Physics. [S0003-6951(99)01434-5].
Synthesis and relationships between the nonlinear optical and holographic properties of dual functional azocarbazole chromophores based on photorefractive polymers
(1999-08-24)
Chang, CJ
;
Whang, WT
;
Hsu, CC
;
Ding, ZY
;
Hsu, KY
Two kinds of dual functional carbazole-based chromophores are synthesized to enhance the photorefractive (PR) performance of the polymers by attaching the electron-donating and electron-accepting groups with a diazo bridge on the 3- and 6-positions of the N-ethylcarbazole. The electron-donating group is N,N-diethanol aminophenyl. The electron-accepting group is either p-nitrophenyl or 5-nitrothiazole. The peak maximum of the UV/vis absorption spectra of the 5-nitrothiazole-containing chromophore PANTAC at 535 nm is longer than that of the p-nitrophenyl-containing PANPAC at 477 nm. Both chromophores exhibit a large first hyperpolarizability in the hyper-Rayleigh scattering experiment due to the extended chain length. The first hyperpolarizability of PANTAC is 1100 x 10(-30) esu, almost the double of that of PANPAC (590 x 10(-30) esu). The diffraction efficiencies of both polymers are the function of the film thickness and the laser beam wavelength with a maximum eta(max) at a thickness d(max) between 15 and 23 mu m Surprisingly, the PANPAC-based PR polymer reveals a higher maximum diffraction efficiency (eta(max)) and better fringe of the stored holograms than the PANTAC-based PR polymer does. Both the PR polymers written/read by the green/red laser have greater eta(max) values than those written/read by the green/green laser. These phenomena are related to the balance between absorption and transmission of the laser beam through the PR polymer.
Frame-based priority scheduling in hybrid IP/ATM networks
(1999-08-25)
Chen, YC
;
Hu, SC
;
Chan, CT
;
Lee, CL
;
資訊工程學系
The exploding growth of World Wide Web applications in recent years has overwhelmed the internet with multimedia traffic. A future performance concern is to keep pace with the quickly growing bandwidth requirements. IP over ATM is a way to relax such requirements. It provides a hybrid approach to support both layer 3 software forwarding and layer 2 ATM hardware switching. A switched virtual connection may be suitable for traffic involving large data transfers and QoS provision like Guarantee Service (GS) applications. In the hybrid IP/ATM networks, the packet-level instead of the cell-Level behavior is the relevant measure of performance. In this paper, we propose a so-called Frame-based Priority Scheduling (FBPS) algorithm far GS applications. FBPS focuses on the packet-level performance while transmitting based on cells. The most attractive feature of FBPS is its simplicity. We provide a systematic analysis of FBPS scheduler and derive the bound on its fairness when the how traffic is shaped by a leaky bucket. It shows that FBPS is competitive with certain complex scheduling disciplines such as PGPS. We also verify our analytical bounds by simulation. (C) 1999 Elsevier Science B.V. All rights reserved.
Cantori barriers in the excitation of a diatomic molecule by chirped pulses
(1999-08-28)
Lin, JT
;
Jiang, TF
;
物理研究所
;
Institute of Physics
We present a nonlinear dynamical study of a diatomic molecule under the interaction of chirped pulses. The step-like dissociation probability with respect to the initial vibrational states reflects the cantori barriers during the excitation process. The correspondence between classical and quantum cantori barriers is shown through classical phase trajectory and quantum Husimi distribution function. According to the results, the quantum suppression of classical dissociation in molecular excitation by chirped pulse disappears at some field parameters.
喘月
(1999-08-29)
管不着
三進桃花源所以暗戀
(1999-08-31)
管管
Cost-effective VLSI architectures and buffer size optimization for full-search block matching algorithms
(1999-09-01)
Yeh, YH
;
Lee, CY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
This paper presents two efficient very large scale integration (VLSI) architectures and buffer size optimization for full-search block matching algorithms. Starting from an overlapped data how of search area, both systolic- and semisystolic-array architectural solutions are derived. By means of exploiting stream memory banks, not only input/output (I/O) bandwidth can be minimized, but also processor element efficiency can be improved, In addition, the controller structure for both solutions are very straightforward, making them very suitable for VLSI implementation to meet computational requirements. Moreover, by exploring the dependency graph, we focus on the problem of reducing the internal buffer size under minimal I/O bandwidth constraint to derive guidelines on reducing redundant internal buffer as well as to achieve area-efficient VLSI architectures. Simulation results show that, for N = P = 16 (N is the reference block size and P is the search range), I/O bandwidth can be reduced by 2.4 times, while buffer size increases less than 38%. Two prototype chips for N = P = 16 have been designed and fabricated. Test results show that clock rate can be up to 90 MHz, implying that more than 87.9-K motion vectors per second can be achieved to meet real-time requirements specified in MPEG-2 MP@ML coding standard.
Bifurcation of fundamental Gaussian modes in Kerr-lens mode-locked lasers
(1999-09-01)
Wei, MD
;
Hsieh, WF
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光電工程學系
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Department of Photonics
We propose that more than one spatial fundamental Gaussian mode may occur in concentric and confocal resonators under persisting nonlinear effect. Extensively studying the influence of the resonator's parameters in a Kerr-lens mode-locked resonator, pitchfork bifurcation results in more symmetrical configurations, and saddle-node bifurcation appears as the symmetry being broken. From the properties of bifurcation, we suggest that the equal-arm and near-confocal resonator is suitable for the emergence of bistability in Kerr-lens mode-locked lasers. (C) 1999 Elsevier Science B.V. All rights reserved.
A high-temperature thermodynamic model for metalorganic vapor phase epitaxial growth of InGaN
(1999-09-01)
Ou, J
;
Pan, YC
;
Lee, WH
;
Shu, CK
;
Lin, HC
A thermodynamic analysis tailored with a high-temperature parameter was performed for metalorganic vapor phase epitaxial (MOVPE) growth of InxGa1-xN alloys. Accordingly, a series of InGaN samples were prepared under various input In flow rates and growth temperatures. Theoretical results indicate that the In solid concentration tends to increase with increasing In flow rate and with decreasing temperature, whereas the metal droplets form more easily on the surface at lower growth temperatures and higher In fluxes, which are in good agreement with our experimental data.
Instruction cache prefetching directed by branch prediction
(1999-09-01)
Chiu, JC
;
Shiu, RM
;
Chi, SA
;
Chung, CP
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資訊科學與工程研究所
As the gap between processor speed and memory speed grow, so the performance penalty of instruction cache misses gets higher. Instruction cache prefetching is a technique to reduce this penalty. The prefetching methods determine the target line to be prefetched generally based on the current fetched line address. However, as the cache line becomes wider, it may contain multiple branches. This is a hurdle which must be overcome. The authors have developed a new instruction cache prefetching method in which the prefetch is directed by the prediction on branches, called branch instruction based (BIB) prefetching; in which the prefetch information is recorded in an extended BTB. Simulation results show that for commercial benchmarks, BIB prefetching outperforms traditional sequential prefetching by 7% and other prediction table based prefetching methods by 17% on average. As BTB designs become more sophisticated and achieve higher hit and accuracy ratios, BIB prefetching can achieve a higher level of performance.
Constructing perfect secret sharing schemes for general and uniform access structures
(1999-09-01)
Sun, HM
;
Shieh, SP
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資訊工程學系
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Department of Computer Science
A perfect secret sharing scheme allows a secret K to be shared among a set of participants in such a way that only qualified subsets of participants can recover the secret, and unqualified subsets of participants obtain no information regarding the secret. In this paper, we propose a construction of perfect secret sharing schemes with uniform, generalized access structures of rank 3. Compared with other constructions, our construction has some improved lower bounds on the information rate. In addition, we also generalize the construction to perfect secret sharing schemes with uniform, generalized access structures of constant rank.
Splitting and merging version spaces to learn disjunctive concepts
(1999-09-01)
Hong, TP
;
Tseng, SS
;
資訊工程學系
;
Department of Computer Science
We have modified the original version space strategy in order to learn disjunctive concepts incrementally and without saving past training instances. The algorithm time complexity is also analyzed, and its correctness is proven.
Effect of bottom electrode materials on the electrical and reliability characteristics of (Ba, Sr)TiO3 capacitors
(1999-09-01)
Tsai, MS
;
Sun, SC
;
Tseng, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The dielectric constant and the leakage current density of (Ba, Sr)TiO3 (BST) thin films deposited on various bottom electrode materials (Pt, Ir. IrO2/Ir, Ru, RuO2/Ru) before and after annealing in O-2 ambient were investigated. The improvement of crystallinity of BST films deposited on various bottom electrodes was observed after the postannealing process, The dielectric constant and leakage current of the films were also strongly dependent on the postannealing conditions. BST thin film deposited on Ir bottom electrode at 500 degrees C, after 700 degrees C annealing in O-2 for 20 min, has the dielectric constant of 593, a loss tangent of 0.019 at 100 kHz, a leakage current density of 1.9 x 10(-8) A/cm(2) at an electric field of 200 kV/cm with a delay time of 30 s, and a charge storage density of 53 fC/mu m(2) at an applied field of 100 kV/cm, The BST films deposited on Ir with post-annealing can obtain better dielectric properties than on other bottom electrodes in our experiments, And Ru electrode is unstable because the interdiffusion of Ru and Ti occurs at the interface between the BST and Ru after postannealing. The ten-year lifetime of time-dependent dielectric breakdown (TDDB) studies indicate that BST on Pt, Ir, IrO2/Ir, Ru, and RuO2/Ru have long lifetimes over ten years on operation at the voltage bias of 2 V.
草原上之小樹呀
(1999-09-01)
管管
Characterization and modeling of out-diffusion of manganese and zinc impurities from deep ultraviolet photoresist
(1999-09-01)
Wang, MY
;
Ko, FH
;
Wang, TK
;
Yang, CC
;
Huang, TY
The radioactive tracer technique was applied to investigate the out-diffusion of manganese and zinc impurities from deep-ultraviolet (DUV) photoresist. Two important process parameters, viz., baking temperature and the type of substrate (i.e., bare silicon, polysilicon, oxide, or nitride), were evaluated. Our results indicated that diffusion ratios were ail below 6%, irrespective of the substrate type and baking temperature. The substrate type did not appear to strongly affect the metallic impurity out-diffusion from DUV photoresist. However, solvent evaporation was found to have a significant effect on impurity diffusion. A new model, together with a new parameter, was proposed to describe the out-diffusion behavior of impurities from DUV photoresist. This model could explain the diffusion ratio of metallic impurities in photoresist layers under various baking conditions. The effectiveness of various wet cleaning recipes in removing metallic impurities such as manganese and zinc was also studied. It was found that (i) bath life due to temperature change can considerably affect the cleaning efficiency, and (ii) hot water immersion can effectively dissolve the impurities from the wafer surface. (C) 1999 The Electrochemical Society. S0013-4651(98)11-080-7. All rights reserved.