摘要:

This paper presents a new incremental algorithm for the computation of characteristic (weighting) patterns and vectors of discrete convolution systems. The method first approximates the system by a real characteristic dyadic form. Considerable savings in computation time are made if this is a good approximation. If not, the estimates are incremented at each instant to find the actual characteristic patterns and dynamic vectors. Numerical examples are given for real dyadic and non-dyadic forms.

ISSN:0020-7721    

DOI:10.1080/00207728708967154

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

This paper extends the application of discrete orthogonal Laguerre functions (DOLFs) to the analysis and parameter identification of linear time-invariant discrete-time systems described by difference equations with non-zero initial conditions. The extension is achieved through deriving a relationship between the DOLF expansion coefficients of a discrete function y(k + 1) and those of the delayed function y(k).

ISSN:0020-7721    

DOI:10.1080/00207728708967155

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

This paper presents some new definitions of the real and imaginary parts and the associated amplitude and phase of a real or complex matrix. Computational methods, which utilize the properties of the matrix sign function and the principal nth root of a complex matrix, are given for finding these quantities. A geometric series method is newly developed for finding the approximant of the matrix-valued function of tan−1(X), which is the principal branch of the arc tangent of the matrixX. Several illustrative examples are presented.

ISSN:0020-7721    

DOI:10.1080/00207728708967156

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

This paper surveys ecological modelling and analysis from the viewpoint of large-scale systems. It will be very helpful to system scientists and engineers newly attacking these fields. It is time for a shift in emphasis from the numerical simulation of ecosystems to the theoretical discussion of fundamental principles. Several topics are presented, as follows: in § 2, the approximation problem—aggregation and decomposition; in § 3, ecological networks—input-output analysis, environ analysis, the information theoretical method, and the Markov chain method; in § 4, a macroscopic discussion—thermodynamical and statistical method, thermodynamic network analysis, and global models of energy flow and material cycling; in § 5, model identification—GMDH, compartmental systems analysis, reconstructibility analysis, and the flow-based modelling method.

ISSN:0020-7721    

DOI:10.1080/00207728708967157

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The Poisson-gamma filter is a technique for updating estimates as new observations become available from a counting process model. It is shown that the Poisson-gamma filter could be used to calculate exact maximum likelihood estimates of the parameters in a counting process model. Adaptive estimation for a counting process model with non-linear intensity is a special case of this technique. Discrete-time models are obtained to handle unequally-spaced data.

ISSN:0020-7721    

DOI:10.1080/00207728708967158

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

This paper deals with a method for the dispatcher control of a broad class of technical, economic and ecologic systems. The method represents a sample system of variable step length, with step change time and control intervention strength chosen in accordance with the requirements of sliding mode operation.

ISSN:0020-7721    

DOI:10.1080/00207728708967159

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A new recursive approach for solving the 1D and 2D inverse Laplace transform problem of rational transfer functions via block-pulse functions is presented. It is shown that the piecewise constant approximations can be calculated recursively from a corresponding difference equation. This approach is thus straightforward, rather simple and suitable for computer programming. Additionally, the calculation size is small. These advantages are valuable, especially when the number of subintervals for block-pulse functions has to be large in order to obtain a satisfactory result, as shown by illustrative examples. By a parallel derivation, similar to the 1D and 2D cases, this approach is also easy to extend to multidimensional problems.

ISSN:0020-7721    

DOI:10.1080/00207728708967160

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

This paper is concerned with an investigation of the detection and estimation of cracks occurring in concrete bridges constructed by Indian Railways. The dynamic behaviour of cracks is modelled by linear viscous dampers at the locations where cracks occur, and the locations are estimated using the least-squares method based on measurable input and output data sequences. The selection of the measurement locations is investigated by numerical simulation, and it is found that the selection of the extremum, or its vicinity, of mode functions characterizing the transverse deflection of the bridges much improves the crack location estimation performance.

ISSN:0020-7721    

DOI:10.1080/00207728708967161

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

An attempt has been made to obtain the probabilities of pregnancy termination by live birth, still birth and abortion, in any particular order, assuming that the termination of pregnancy is associated with three competing ‘risks’, i.e. live birth, still birth and abortion, which need not necessarily operate at the same point of time. A probability model has been constructed to obtain the conditional probability of live birth/still birth/abortion given that the previous pregnancy has been terminated by a particular one of the three. The correlation coefficient between the outcomes of two particular consecutive pregnancy terminations, viz. live birth and reproductive wastage (which includes both abortion and still birth), has also been obtained. Given data pertaining to sample correlation coefficients between the nature of consecutive orders of the outcomes of conception from first to sixth, an exercise has been undertaken to estimate parameters relating to the ‘hazard’ rates of live births, still birth and abortion. The exercise further enables one to test the well-known demographic hypothesis that reproductive wastages follow each other in succession over consecutive orders of the outcomes of conception.

ISSN:0020-7721    

DOI:10.1080/00207728708967162

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The present exercise is an attempt to generalize a probability model referring to the waiting time distribution for conception in a mixed group of fecund females with two varying levels of fecundity, based on a census sample truncated at timeT=t from the date of resumption of fecundity following an earlier conception (Biswas, 1975, Sankhya, Series B, 37, Part III). The generalization is made in two aspects, viz. instead of fixed conception rates, time-dependent rates decreasing with the age of the woman have been used. Additionally, unlike the model of Biswas (1975) consisting of two different fecund groups, three different levels of fecundity have been taken into consideration in this paper. Estimates of the proportion of fecund females over time, viz. πi(t) (i = 1, 2, 3) are attempted by the method of maximum likelihood on the basis of a census sample truncated at timeT= t under the generalized set up.

ISSN:0020-7721    

DOI:10.1080/00207728708967163

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor