An analytic model for the performance evaluation of space-division asynchronous transfer mode (ATM) switches is presented. This model assumes that the switch has a fixed capacity of m, where 1/spl les/m/spl les/N (N i...
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An analytic model for the performance evaluation of space-division asynchronous transfer mode (ATM) switches is presented. This model assumes that the switch has a fixed capacity of m, where 1/spl les/m/spl les/N (N is the number of trunks). Other important parameters include arrival rate and buffer sizes. Numerical solutions for the maximum throughput, cell delay, and cell loss probability are given with simulation being utilized in order to validate the analytic model. For independent and identical Bernoulli arrivals, the study shows that the contention processes can be modeled as discrete M/D/m (FIFO or Random) queues, while input queues can be modeled by Geom/G/1 queues, and the output queues are G/sup [X]//D/1 queues. A closed-form approximation for cell delay when m>2 is given. The result shows that the performance of switches with a small capacity can approach that of output queueing. The model and result can be used for switch design analysis and higher layer performance models.
We present a comparative analysis of bandwidth access control schemes under nonstationary traffic conditions for heterogeneous circuit-mode traffic offered to a B-ISDN network link. A unified model for analysing the b...
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We present a comparative analysis of bandwidth access control schemes under nonstationary traffic conditions for heterogeneous circuit-mode traffic offered to a B-ISDN network link. A unified model for analysing the behavior of several bandwidth access control schemes is developed using a Markov process model with acceptance functions. Numerical techniques are used to solve the associated Chapman-Kolmogorov equations and determine the nonstationary behavior. Performance results are given for several common bandwidth access control schemes, namely: complete sharing, complete partitioning, partial sharing, classical trunk reservation, and the probabilistic reservation policy. It is shown that the use of the average arrival rate to estimate the average connection blocking rate may be an underestimate for a system with a time varying arrival process. Also, it is found that a nonstationarity in one traffic class arrival process can impact other stationary traffic classes and the degree of variability depends on the particular access control scheme.
Fiber optic oblique incidence reflectometry has been demonstrated to be a simple and accurate method for measuring the optical properties, μa and μs', of turbid media such as biological tissues [1,2]. After samp...
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The advantages of single electron devices with asymmetrical tunnel barriers (ATBs), proposed by the authors, over conventional single electron devices with symmetrical tunnel barriers (STBs) are discussed by referring...
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The advantages of single electron devices with asymmetrical tunnel barriers (ATBs), proposed by the authors, over conventional single electron devices with symmetrical tunnel barriers (STBs) are discussed by referring to the features of ATBs and the results of computer simulation of the performance of tunnel-junction-load SET logic and turnstile devices. Experimental observation of a Coulomb staircase and asymmetrical tunnel characteristics in ATBs fabricated with GaAs/AlGaAs heterostructures are also reported.
The progress in understanding wafer-fused vertical-cavity lasers and improvements in fabrication techniques have led to the realization of the first room-temperature continuous-wave operating 1.54-/spl mu/m vertical-c...
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The progress in understanding wafer-fused vertical-cavity lasers and improvements in fabrication techniques have led to the realization of the first room-temperature continuous-wave operating 1.54-/spl mu/m vertical-cavity lasers. By demonstrating continuous-wave operation at room temperature using vertical-cavity lasers fabricated by two wafer fusion steps, we have shown that wafer fusion is a viable technique. The lasers comprise strain compensated InGaAsP quantum-well active layers sandwiched between two AlGaAs/GaAs quarter-wave mirrors. Characteristics discussed include cavity losses, the gain-current density relationship, and voltage-current characteristics.
This paper presents a distributed simulator for performance analysis of various applications in the asynchronous transfer mode (ATM) environment. The simulator is used to determine how the quality of a service, either...
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This paper presents a distributed simulator for performance analysis of various applications in the asynchronous transfer mode (ATM) environment. The simulator is used to determine how the quality of a service, either synchronous or asynchronous, is affected when it is transmitted through an ATM network under various traffic conditions. The simulator has been implemented in a distributed Unix environment using network and operating system functions and simulates the three lower layers of B-ISDN. It has been based on the time-driven approach, and is modular and expandable because it uses standard operating system calls for adapting new applications and services to the simulator environment. The paper presents performance analysis results of constant and variable bit rate services, as well as experimental results on compressed and uncompressed image transmissions.
There is current interest in the development of legged robotic devices inspired by biological walking systems. We have developed an actuator for this type of device that closely emulates the performance of muscle. The...
作者:
Zhuang, XPKoshiba, MTsuji, YFaculty of Engineering
Hokkaido University Sapporo Japan 060 Graduated from the Department of Communication Engineering
Guellin Electronic Institute China in 1986. She received her M.S. degree from Hokkaido University in 1991 and was admitted to the doctoral program. She has been engaged in research on the optimum design of magnetooptic waveguides for nonreciprocal optical devices. Graduated in 1971 from the Department of Electronic Engineering
Hokkaido University where he received his M.S. degree in 1973 and his Dr. of Eng. degree in 1976. In 1976 he became a Lecturer in the Department of Electronic Engineering Kitami Institute of Technology where he was promoted to Associate Professor in 1977. In 1979 he became an Associate Professor at Hokkaido University where he was promoted to Professor in 1987. He has been engaged in research on optical and wave electronics. In 1987 he received a Best Paper Award. He is the author ofFundamentals of Finite Element Method of Optics and Waves(Morigkata Publ.)Optical Waveguide Analysis(Asakura Publ.)Optical Waveguide Analysis(McGraw-Hill Book Co.) andOptical Waveguide Theory by the Finite Element Method(KTK Scientific Publishing/Kulwer Academic Publishers). He is also co-author of one book and has written chapters in six other books. He is a member of the Institute of Television Engineers of Japan the Institute of Electrical Engineers of Japan the Japan Society for Simulation Technology the Japan Society for Computational Methods in Engineering and the Japan Society of Applied Magnetics and Mechanics. He is also an IEEE Senior Member. Graduated in 1991 from me Department of Electronic Engineering
Hokkaido University where he received his M.S. degree in 1993. He is currently in the doctoral program. He has been engaged in research on quantum wave phenomena and computer-aided design of optical and quantum effect devices.
To evaluate nonreciprocal mode conversion characteristics in a magnetooptic channel waveguide, a finite element analysis based on the scalar wave approximation is formulated for the first time. A simple iterative calc...
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To evaluate nonreciprocal mode conversion characteristics in a magnetooptic channel waveguide, a finite element analysis based on the scalar wave approximation is formulated for the first time. A simple iterative calculation method is conceived for solution of the nonlinear eigenvalue equations finally obtained in which the two polarizations are coupled. Specifically, the maximum isolation ratio in the mode-conversion-type magnetooptic rib guide was evaluated and the validity of the method is confirmed by comparison with published experimental results.
The usual advice given to a first year student is that while the student is reading lectures notes or working with a textbook at home, he has to try to perform the derivations on his own, and even to try to first find...
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The usual advice given to a first year student is that while the student is reading lectures notes or working with a textbook at home, he has to try to perform the derivations on his own, and even to try to first find his own way to solve the problem example, and only after that to study these details in the source. It is thought, reasonably, that in this way, the study will be effective and the student will acquire good comprehension and obtain new tools which could then be actively used. However, this advice is only a part of more complete and self-consistent advice. This paper presents more complete advice which consists of three parts, of which the first is the advice already considered.
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