摘要:

AbstractA digital image is represented by elements of a vector space whose dimensionality equals the number of pixels and linear spatial degradation of a picture is regarded as a linear operator on the vector space. In existing picture restoration theories, especially the theory using a numerical analysis method, this operator is represented by a matrix and the restoration problem is treated as that of obtaining the generalized inverse. In this restoration theory, as the number of pixels increases, the dimensionality of the matrix becomes so large that it becomes very difficult to compute the inverse matrix. In this paper, the generalized Laplacian which is constructed from the linear operator representing degradation is introduced and, by using this operator, the original picture can be restored with high accuracy, simple operations and short computation time. This theory is very effective if the degradation operation is shift‐invarian

ISSN:8756-6621    

DOI:10.1002/ecja.4400661102

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

年代:1983

数据来源: WILEY

摘要:

AbstractGenerally, the switched capacitor filter (SCF) is composed of capacitors and switches which operate with constant period T and sometimes contain operational amplifiers. This paper considers an SCF having an extra switch which operates by the period 2MT (M; integer). the stability of the circuit is investigated when two SCF characteristics are switched alternately in the time domain by the newly added switch. Zeroinput response of the second‐order SCF with an additional switch is expressed by the linear difference equation with periodic coefficient. the stability of the solution of this difference equation is investigated. As a result it is shown that even if each characteristic of the SCF is stable individually, the system may become unstable when the two characteristics are switched in the time domain by the newly added switch. the stability conditions and the boundary curves from stability to instability are obtained. Further, corresponding instability phenomena are confirmed by experimen

ISSN:8756-6621    

DOI:10.1002/ecja.4400661103

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

年代:1983

数据来源: WILEY

摘要:

AbstractA recursive ϵ‐nonlinear filter that removes random noise from signals with sharp discontinuities is proposed. It consists of a linear recursive low‐pass filter with the addition of simple nonlinear fuctions. the proposed filter with a smaller number of taps is as effective as the nonrecursive ϵ‐filter repored previously. Methodologies, realizations, and stability problems of the proposed filter are discussed. It is shown that the filter must be realized in cascade form for stable operation. Realizations of the multistage recursive ϵ‐filter should be used from consideration of

ISSN:8756-6621    

DOI:10.1002/ecja.4400661104

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

年代:1983

数据来源: WILEY

摘要:

AbstractA way of controlling large‐scale systems that have unknown parameters is a decentralized version of the model reference adaptive control. the idea is to construct adaptive controllers for each subsystem so that the overall system becomes an adaptive control system. the strategy does not always work successfully, however, because the information structure for control is decentralized. This paper aims to provide conditions under which we can construct such decentralized adaptive control systems. We first clarify the constraints to which the given system must conform whichever scheme of adaptive control we employ at the subsystem level, and present conditions which must be satisfied between the given system and the reference model. Then we consider adaptive control laws of the parameter adaption type and give classes of reference models with which they can be implemente

ISSN:8756-6621    

DOI:10.1002/ecja.4400661105

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

年代:1983

数据来源: WILEY

摘要:

AbstractKevorkian's decomposition method is known as one of the methods to decompose a large‐scale system of nonlinear equations into systems of equations with lower dimensions. However, his method suffers from the property that errors are included in the decomposed equations, function values, and the Jacobian matrix. Consequently, it is important to discuss the convergence of the solution algorithm and to improve the convergence speed, taking those errors into account. This paper presents an algorithm for the solution of systems of nonlinear equations using Kevorkian's decomposition method. the convergence property of the proposed method is discussed, indicating that the algorithm gives local quadratic convergence under some suitable conditions. A sufficient condition is given first for the existence and differentiability of the mapping G obtained by decomposition. Then a discussion is made of the errors in the equations and the function values by Kevorkian's method. A solution algorithm is proposed which retains the quadratic convergence under those errors, leading to a theorem for convergence. A numerical example is given, indicating that the quadratic convergence can be realized by the proposed method. A comparison is made with the case without using the proposed method, demonstrating its effectivenes

ISSN:8756-6621    

DOI:10.1002/ecja.4400661106

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

年代:1983

数据来源: WILEY

摘要:

AbstractMany second‐order active filters with operational amplifiers have been proposed. Modeling the operational amplifier with nullators and norators, or else with an equivalent circuit with controlled sources, the transfer function is determined and matched with the desired filter function.In this paper, a new equivalent circuit is given for these filters. This is done by selecting three terminals in the circuit—the input and output terminals, together with another arbitrary terminal within the circuit—yielding a structure formed by a fundamental inverse‐L circuit and a controlled source. the voltage transfer function is then given as the product of the inverse‐L voltage ratio and the amplifier gain.Using this equivalent circuit, any filter may be represented by an inverse‐L structure with any of the following two sets of elements: (1) inductance or FDNR, or (2) negative RC elements. Since the operation of the inverse‐L filter can be analyzed easily merely by comparison with the operation of LC filters, the properties and operation of the active RC filters can

ISSN:8756-6621    

DOI:10.1002/ecja.4400661107

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

年代:1983

数据来源: WILEY

摘要:

AbstractStudies of fixed point algorithms have advanced greatly in the last decade. These algorithms have been developed to construct globally fixed points of finite‐dimensional continuous maps, to which existence of fixed points is guaranteed by, for instance, Brouwer's fixed point theorem. However, it is pointed out that these algorithms become progressively slower with increasing dimension. In this paper it is shown that the vector labelling algorithm, one of the typical fixed point algorithms, can be performed efficiently in parallel on a suitable array processor system. Under certain conditions, the time complexity of the vector labelling algorithm is determined by pivot operations. It is shown that high parallel efficiency about 0.9 is attained by executing these pivot operations on our array processor. to further speed up the algorithm, a method is also shown for evading matrix inversion formerly needed at the beginning of the vector labelling algorith

ISSN:8756-6621    

DOI:10.1002/ecja.4400661108

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

年代:1983

数据来源: WILEY

摘要:

AbstractPreviously, the algebraic error‐correcting codes have usually been investigated independently for each error type [random, burst or compound]. the demand for high‐performance error‐correcting codes, however, has increased considerably due to the remarkable progress on many fields of digital communication. to meet this demand, a new research direction has been adopted by Matt‐Massey, Wang and the authors, reevaluating the burst‐error‐correction capability of the cyclic codes.In this paper an algorithm based on the generator matrix is proposed to analyze the burst‐error‐correction capability of cyclic codes. This algorithm appears particularly efficient in terms of the amount of computation. to apply the method in practice, a number of burst‐error‐correction cyclic codes has been investigated, and this paper presents some of the results obtained. Finally, a very interesting conjecture is given, which relates to the burst‐error‐correction capability of the maximum

ISSN:8756-6621    

DOI:10.1002/ecja.4400661109

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

年代:1983

数据来源: WILEY

摘要:

AbstractLevinson's algorithm is one of the fast algorithms for estimating the parameters of an auto‐regressive model. Since this algorithm is recursive with respect to the order of a model, it is an effective method to obtain models of various orders when the true order is unknown. This paper proposes a fast algorithm to estimate the parameters of an autoregressive and a movingaverage model. the parameter estimation can be accomplished using a criterion based on the least square method. the problem of estimating autoregressive and moving‐average parameters from the criterion is reduced to that of solving a 2 × 2 block Toeplitz matrix. This method is an algorithm to solve this block Toeplitz matrix rapidly and it does not require the calculation of the inverse matrix. Also, it is recursive with respect to the order; the orders of an autoregressive model and a moving‐average model can be changed independently of each other. This method is an expansion of Levinson's algorithm and this paper shows the relationship between this method and Levinson's algorithm. Furthermore, properties of this method are discussed and as an example of its application, an experiment of model reduction is per

ISSN:8756-6621    

DOI:10.1002/ecja.4400661110

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

年代:1983

数据来源: WILEY

摘要:

AbstractA high‐accuracy cesium atomic oscillator is used as a clock for a digital communication network, in which, for instance, three cesium oscillators are used to take statistical average with the aid of a reference clock. We will discuss the algorithm for monitoring the frequency error by assuming a step frequency deviation. It has been confirmed that the algorithm satisfies the CCITT Time Interval Error requirements and that it switches to a normal cesium oscillator when frequency error is detecte

ISSN:8756-6621    

DOI:10.1002/ecja.4400661111

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

年代:1983

数据来源: WILEY