摘要:

AbstractThe problem of representing a communication network in a graph and evaluating the overall reliability is NP‐hard. The class of graphs called planar CF graphs is the maximum class whose exact overall reliability is confirmed as being possible to be evaluated by the polynomial order.In this paper, the dual graph to the given graph is constructed, and the overall reliability is evaluated. As a result, the following properties are obtained.(1)The evaluation of the overall reliability is equivalent to the evaluation of the probability that a circuit exists in its dual graph (dual problem).(2)The exact value of the dual problem can be evaluated by the reduction method.(3)There exists a class of graphs which permits the evaluation of the overall reliability by the polynomial order using the method of property (2), and is larger than the Planar CF Graph (we call this extended class Planar Dual CF Graph

ISSN:1042-0967    

DOI:10.1002/ecjc.4430741001

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThe bathtub curve has been represented as a composite curve, where the failure pattern consists of separate initial, chance and wear‐out periods. On the other hand, some electronic system is regarded as a “system composed of subsystems whose failure patterns are different from each other”. It may happen that the failure pattern of the whole device of such a system is of a bathtub type. This paper discusses failure pattern analysis, where such a situation is modeled as a “superimposed process” of nonhomogeneous Poisson processes and proposes a computational algorithm for the maximum likelihood estimation of its parameters, where the failure pattern of the subsystems follows the Weibull processes. The results of numerical experiments indicate that this method derives an accurate solution efficiently and in a stable way. As an application to the practical problem, the model is used to analyze the failure pattern of the ground device of the Shinkansen (bullet train) automatic train control system (ATC). The failure patterns of some kinds of components are revealed, which have never been analyzed due to their c

ISSN:1042-0967    

DOI:10.1002/ecjc.4430741002

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractA few years ago a fundamental theory on natural observation of waveforms was published as the foundation of a new effective method instead of Fourier analysis. In this paper a natural observation filter is proposed based on the theory. The filter has a typical property with regard to perfect reconstruction for a certain characteristic waveform group. The algebraic relation between the structure of the filter and the corresponding waveform group is theoretically clarified. The result of the present paper is expected to be applicable for recognition problems of various waveforms.

ISSN:1042-0967    

DOI:10.1002/ecjc.4430741003

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractIn nonlinear programming problems, an objective functionf(x) is optimized (maximized or minimized) subject to some constraints. Such problems are also called constrained optimization problems. Most of the algorithms in nonlinear programming are classified into two categories: 1) transformation methods; and 2) projection methods.The homotopy methods, which are the subject of this paper, belong to the category of projection methods. The main feature of the homotopy methods compared with other projection methods is that they are good at global convergence (which is lacking in most of the projection methods) but are not good at convergence speed (which is the strong point of most of the projection methods).This paper discusses the homotopy methods in nonlinear programming and show that the piecewise‐linear homotopy method using the Newton homotopy and polyhedral subdivision is very effective for solving nonlinear optimization problems. A new algorithm is proposed that exploits the partial separability and linearity of the Kuhn‐Tucker equations (which appear in the nonlinear programming problems). By this exploitation, the computation efficiency is improved markedly compared with the conventional homotopy methods using simplicial subdivision. Moreover, the proposed algorithm converges quadratically, thus accurate solutions can be obtained rapidly. It is proved also that the proposed algorithm is globally convergent for the constrained convex optimization problems. Except for the shortcoming that the programming is complicated, the proposed algorithm has wellbalanced effectiven

ISSN:1042-0967    

DOI:10.1002/ecjc.4430741004

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThe smoothed group delay spectrum distance (SGDS) measure is evaluated in speaker‐independent recognition experiments. First, the appropriate level of smoothing of the group delay spectrum (GDS) is investigated by adding noise, etc., to the input speech. Then a comparison with the speaker‐dependent case is made. An experiment is reported in which, for low amplitude parts of speech (e.g., unvoiced speech), the standard (LPC) distance measure is used in the interframe distance calculation instead of the SGDS distance measure. This method prevents a loss of recognition accuracy due to too strong an emphasis on certain spectral elements and a consistently high recognition accuracy can be achieved.Finally, evaluate the SGDS distance measure is evaluated where the GDS is represented in the spectral domain as a discrete Fourier transform (DFT) of the LPC coefficients. In comparison to the SGDS which was calculated by weighting the LPC cepstrum co‐efficients, computation time and memory space can be reduced without loss of recognition accuracy. Furthermore, a low bit quantization of the GDS is reported and a high recognition rate is achieved with only 32 bits per

ISSN:1042-0967    

DOI:10.1002/ecjc.4430741005

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractA technique is developed for designing 2‐D separable‐denominator digital filters in the spatial domain. First, a given 2‐D FIR digital filter is realized in a canonic form by the Roesser model whose transfer function is separable in the denominator. Then, the reduced‐order model is obtained using eigenvalue‐eigenvector decomposition on the impulse response Grammians derived from the realization.The proposed technique utilizes the impulse response Grammians considered here for 2‐D separable‐denominator digital filters, which are extensions of those proposed for single‐input/single‐output 1‐D linear systems. The stability of the resulting filter is always guaranteed. Finally, two numerical examples are given to illustrate the utility of the

ISSN:1042-0967    

DOI:10.1002/ecjc.4430741006

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractFormant estimation from a speech signal that is observed acoustically is importand for speech analysis and synthesis. This paper proposes an adaptive formant estimation method with compensation for the gross spectral shape. This estimator can estimate the center frequencies and the bandwidths of formants (anti‐formants) based directly on the pole‐zero transfer function represented by the products of the secondand first‐order factors. Since the proposed method can compensate the gross spectral shape adaptively, excellent formant estimation is expected for continuous speech whose gross spectral shape is time‐varying. Therefore, the method proposed herein is applied to the synthetic signal and real speech, and the validity of this method is demonstrated. Furthermore, the Single‐Stage Iteration Filter is the estimation algorithm introduced for use in the proposed method. It is shown that the estimation results of tracking with little degradation are obtained stably in the transient part of th

ISSN:1042-0967    

DOI:10.1002/ecjc.4430741007

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThis paper describes a novel design of a linear‐phase FIR filter and its hardware. The proposed filter has a hierarchical building block structure of tapped‐cascaded lower‐order subfilters. Since this architecture can reduce the sensitivity of the rounded filter coefficients, an effective high‐speed processing of the subfilter can be performed by using adders instead of multipliers. Also, identical subfilters are arranged regularly so that the architecture is suitable for LSI implementation. Another important feature is that the design of the higher‐order FIR filter can be replaced with that of the lower‐order subfilter. An LSI implementation of about a 45‐order FIR filter also

ISSN:1042-0967    

DOI:10.1002/ecjc.4430741008

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractSupervisory control initiated by Ramadge and Wonham is a very useful control technique for discrete‐event systems. A supervisor realized by a finite automaton is called a finite state supervisor. It is clear that a finite state supervisor exists for every regular controllable language. It is very important to show a necessary and sufficient condition for the existence of a finite state supervisor. Moreover, there are few studies for the effect of nondeterminism in a supervisor on control.First, this paper shows that there exists a deterministic finite state supervisor for every control specification for which a nondeterministic finite state supervisor exists. Then a necessary and sufficient condition for the existence of a finite state supervisor is proved. As a result, it is shown that no finite state supervisor exists if a controlled discrete‐event system is modeled by a finite automaton and control specification is given by a nonregular language. Finally, a simple manufacturing system and a nonregular control specification (for which a finite state supervisor exists) are demonstra

ISSN:1042-0967    

DOI:10.1002/ecjc.4430741009

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractIn a VLSI layout design using the building block approach, the design is divided into two phases, placement and routing. On the other hand, a new hierarchical floorplanning method was proposed by Dai et al., in which a global routing for the evaluation of the placement is determined simultaneously during the design of relative placement. However, the precise estimation of routability is difficult since the global routes in this method do not correspond to the routing region such as channels and switchboxes. In this paper, a new method is proposed, which simultaneously and hierarchically obtains floorplan, shapes and positions of modules, and global routes which directly correspond to switchboxes and channels. In this method, the routing‐based partitioning, the hierarchical detailed global routing, and the hierarchical positioning are repeatedly executed, and a chip with small area and short wire length is obtained. This paper presents these three algorithms, and discusses the experimental results of each algorithm and the whole proposed method in a comparison to the conventional method that separately executes placement and routin

ISSN:1042-0967    

DOI:10.1002/ecjc.4430741010

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY