摘要:

Since many industrial processes are essentially linear multivariable type-one plants (i.e. linear multivariable plants with unbounded step-response matrices but with bounded impulse-response matrices), the methodologies of Porter and Jones (1986) for linear multivariable type-zero plants are extended to embrace such linear multivariable type-one plants. It is shown that the proportional and derivative controller matrices in the resulting PD controllers can be directly determined from open-loop impulse-response tests performed on linear multivariable type-one plants. The disturbance-rejection properties of these controllers are fully developed by modifying the digital PD controller by the inclusion of an outer PID loop. The robustness propertcs of these PD-PID controllers are assessed by characterizing, in terms of the steady-state impulse-response matrices of nominal and actual plants, the admissible plant perturbations that can be tolerated. The effectiveness of this design methodology is illustrated by designing a tunable digital set-point tracking PD-PID controller for a steel mill.

ISSN:0020-7721    

DOI:10.1080/00207729008910377

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

A class of compensated parameter identifiers is utilized to generate bias-free parameter estimates in the presence of noise disturbance which accounts for the uncertainties in the system. A forward feedback is used to minimize the effect of noise. The observer form of state variable modelling is used to synthesize a ladder circuit whereby the compensated parameter identifiers are asymptotically stable, with rapid convergence. A new technique is applied to derive state feedback that assures the assignment of closed-loop eigenvalues in arbitrary sectors within the unit circle.

ISSN:0020-7721    

DOI:10.1080/00207729008910378

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

A model is represented for deriving analytically the optimal lot size when a percentage of the produced items is defective. It is shown that the total unit cost increases as the defective percentage and/or the defective Denaltv cost increase. The effect of learning is also studied and it is shown that the total unit cost decreases as the learning level increases due to the negative effect of learning on both the actual defective percentage and the unit production time. It is also shown that anticipated total unit cost increases, due to increasing theoretical defective percentages, can be almost eliminated when high levels of learning are applicable. Finally the model is extended to the multiple item case with limited resources.

ISSN:0020-7721    

DOI:10.1080/00207729008910379

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

An analytical procedure is presented for determining the mean and standard deviation of job flow-time in a job shop by computing the mean and variance of a random number of random variables. The procedure is applied in the case of a job shop with machines subject to random breakdowns and in the case of a job shop with two classes of jobs. Simulation results validate the analytical procedure but they also show that significant departures from the equal mean processing times assumption have an adverse effect on the accuracy of the analytical results. An expression for the optimal work in process inventory level is also developed for a job shop with machines subject to random breakdowns or with two classes of jobs.

ISSN:0020-7721    

DOI:10.1080/00207729008910380

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The rational approximation of two-dimensional (2D) digital filters in the spatial domain is examined. Non-iterative methods are presented for finding 2D recursive digital filters to approximate, in some sense, a desired 2D pulse response over a finite area. The methods require only linear calculations and they are quite straight forward. Two examples are given to illustrate the utility of the presented techniques.

ISSN:0020-7721    

DOI:10.1080/00207729008910381

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

An operating orbit system with two dissimilar units is studied. The orbit is said to be in an operative state if both of its units are good and one is operative at a time. Two units are kept in standby for replacing the units in the orbit. As soon as a unit of the orbit fails, the corresponding standby unit immediately takes its place. The system is said to have failed if at least two similar units fail. Only the totally failed systems are repaired. Using regenerative point technique, some important reliability characteristics of interest have been obtained.

ISSN:0020-7721    

DOI:10.1080/00207729008910382

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The problem of transforming affine non-linear systems into linear systems is considered, Necessary and sufficient conditions for a non-linear affine system with a nonlinear output to be equivalent to a linear system with a linear output are discussed. In addition, the invariance properties of controllability and observability under smooth state-space coordinate changes are investigated.

ISSN:0020-7721    

DOI:10.1080/00207729008910383

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The concept of mean variance efficiency widely used in portfolio theory of modern finance is examined here in terms of (a) its limitations in statistical and empirical applications and (b) the alternative non-parametric measures. The non-parametric measures and tests of portfolio efficiency raise some of the most fundamental issues of modern financial economics today and these are shown to have valuable implications for the theory of capital market efficiency.

ISSN:0020-7721    

DOI:10.1080/00207729008910384

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The optimal fixed-point smoother is derived for white gaussian plus coloured observation noise when the covariance information for the signal, the coloured and white gaussian observation noises, and the observed value are available.

ISSN:0020-7721    

DOI:10.1080/00207729008910385

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

A stack sequential decoding algorithm is used estimate states of dynamic models with an Nth-order memory.The state at the future and observation at the present are linear or non-linear functions of the disturbance noise, the observation noise, and either the present or N - 1 past discrete values of the state. States are estimated by approximating the state model by a finite state machine and then using a stack sequential decoding algorithm of Information Theory. The proposed suboptimum scheme is faster and more practical than the estimation schemes using the Viterbi decoding algorithm.

ISSN:0020-7721    

DOI:10.1080/00207729008910386

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor