ISSN:0253-3839    

DOI:10.1080/02533839.1996.9677775

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

In this paper, we propose an efficient way for the arrangement of multiple key hashing (MKH) files onto a multiple disc system. We present a greedy strategy to find a proper set of parameters of a hashing function that determines the near “optimal” bucket distribution for facilitating the maximal concurrency of disc accesses. Some experimental results are given to show that our greedy method works well in general cases and can achieve the same performance as the previously proposed method, that can only be used in some restricted cases.

ISSN:0253-3839    

DOI:10.1080/02533839.1996.9677776

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

In this paper, an artificial neural network (ANN) has been proposed to solve the load forecasting of distribution substations and to investigate the temprature sensitivity of substation loading. Hourly substation load data are collected by the supervisory control and data acquisition system (SCADA). Substation load data are then integrated with weather information to form a training set of supervisory neural network with back propagation function link. To verify the performance of the proposed method, actual substation load data and weather data are used as the recall data sets of the ANN to perform the distribution substation load forecasting for the next year. To demonstrate the effectiveness of the proposed ANN method, the conventional multi‐variable linear regression technique has been applied to solve substation load forecasting for the purpose of comparison.

ISSN:0253-3839    

DOI:10.1080/02533839.1996.9677777

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Formal Description Techniques (FDTs) provide formal support for each phase of protocol development. Estelle is one of the FDTs proposed by the International Organization for Standardization (ISO) to formally specify distributed systems, especially for communication protocols. In this paper, we present the development of an Estelle translator which allows protocol designers to interactively add/delete transitions at the run time of protocol verification. The Estelle translator can translate Estelle‐specified protocols into the internal extended finite state machine tables, which have corresponding information of each protocol entity. The main feature of the Estelle translator is its capacity to support incremental protocol verification. The incremental translating components in our Estelle translator allow protocol designers to modify protocols at the run time and continue the verification at the modification point incrementally. That is, our Estelle translator allows protocol designers interactively modifying Estelle‐specified protocols in order to eliminate logical errors at the run time, interpret the modified part, and then continue verification incrementally at the modification point. In this way, protocol designers can design Estelle‐specified protocols interactively and incrementally using our translator.

ISSN:0253-3839    

DOI:10.1080/02533839.1996.9677778

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

In this paper, a methodology is proposed to design a robust fuzzy controller for a positional control system. This fuzzy controller is based on the Proportional‐Integral‐Derivative control scheme with fuzzy if‐then rules and the triangular membership functions. The design of the new structure of this PID fuzzy controller is presented. Also the characteristics of the PID fuzzy controllers are analyzed. The simulation results for positional control systems with a second or a third order plant are included to show that the PID fuzzy controllers out‐perform the traditional PID controllers in the sense of robustness. Moreover, simulation results of a fourth order plant are provided to empirically illustrate the effectiveness of the design approaches for higher order systems.

ISSN:0253-3839    

DOI:10.1080/02533839.1996.9677779

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

In this paper, we study the multiple‐fault detection methods for a class of multistage interconnection networks using the totally exhaustive combinatorial model [8,9,11] with multiple‐fault assumption. We find that six tests are sufficient and necessary for detecting multiple faults of the 4*4 and 8*8 baseline networks with two valid states plus that the number of tests is double as the network size doubled. We show that multiple faults can be detected by 2log2N tests in an N*N baseline network with two valid states, N ≥ 8. This improves upon the previous results of [8] which need 2log2N + 2 tests to accomplish the same task. We also prove that, if K distinct vectors are sufficient for diagnosing an R*R baseline network with two valid states, then 2[log2(N*K/R+2)] tests are sufficient for diagnosing an N*N baseline network with two valid states for N ≥ R. To detect the multiple faults of an N*N reverse baseline network with four valid states, we have developed a new and systematic procedure in which multiple faults can be detected by (4log2N + 2) tests, N ≥ 8. This is also more efficient than the results of [9] which need (6log2N + 2) tests.

ISSN:0253-3839    

DOI:10.1080/02533839.1996.9677780

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A series of step‐by‐step integration methods has been effectively developed which does not increase the total number of equations of motion and avoids the use of the derivatives of external force. The well‐known Newmarkβmethod [16] withβ= 1/4 is the lowest order of accuracy of this series of methods. All the algorithms of this series are unconditionally stable, without overshoot in displacement or in velocity, and they do not possess any numerical dissipations. The rapid changes of dynamic loading can be automatically overcome. It is also verified that the higher the order of the integration method, the more accurate. Consequently, the higher‐order algorithms of this series allow the use of a large time step in step‐by‐step dynamic analysis. Thus, they are competitive in dynamic analysis, especially when the response of a long duration is of interest.

ISSN:0253-3839    

DOI:10.1080/02533839.1996.9677781

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The steady‐state analysis of the lossy parallel resonant converter is presented with closed‐form expressions. The phase difference between the input square‐wave voltage and the output square‐wave current which excite the resonant tank is used as the parameter to plot the converter output current and voltage characteristic for given damping ratio and switching frequency. The load line can be superimposed on the output characteristic to determine the operating point and the value of the associated parameter (by using linear interpolation), which can be used to plot the resonant‐tank waveforms. The upper bound of the switching frequency can be found as a function of the threshold voltage of the output rectifier and is practically independent of the damping ratio. The effect of damping is serious when the switching frequency is near resonance in that the output characteristic is far from an ideal current source as in the lossless case. The analysis results can be used in the design and optimization of the parallel resonant converter

ISSN:0253-3839    

DOI:10.1080/02533839.1996.9677782

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Effects of chopped illumination on the electrical noise of Schottky diodes are studied theoretically and experimentally. It is shown that the noise spectra of a bare diode illuminated by a He‐Ne laser show certain structures at specific frequencies. A theoretical model is presented for the observed noise spectra. Our theoretical results agree well with the experimental data. A periodic pulse voltage method is used to measure the equivalent voltage due to light illumination. This method can be used to find the equivalent photocurrent and quantum efficiency of Schottky diodes.

ISSN:0253-3839    

DOI:10.1080/02533839.1996.9677783

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The conjugate gradient method of minimization with adjoint equation is used successfully to solve the inverse problem in estimating an appropriate boundary control function such that the phase front moves at a desired velocity in the Stefan problem.

ISSN:0253-3839    

DOI:10.1080/02533839.1996.9677784

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor