摘要:

This paperpresents optimal production strategies for respondingto an anticipated unit cost increase. Analytical expressions for a special lot-size are developed for the cases where the unit cost increase announcement either coincides with the end of an inventory cycle or falls in the non-production period of an inventory cycle. It is shown that in the latter case the optimal strategy depends on the amount of remnant inventory, i.e. the production of a special lot-size is immediately initiated after the unit cost increase announcement is made when the remnant inventory is low, otherwise no special action is taken. It is also shown that when the unit cost increase announcement falls in the production period of an inventory cycle, the current production run should be extended until a special lot-size is produced. Finally, the model is extended to cover the backorder case, and by using the Lagrange multipliers technique the multi-item case is also considered under a constraint on the total amount that can be spent.

ISSN:0020-7721    

DOI:10.1080/00207729308949468

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The sufficient conditions of exponential insensitivity of stochastic composite systems are established. In this case the objective is to analyse composite systems in their lower order subsystems and in terms of their interconnecting structure. The proposed qualitative analysis is very close to the stability analysis of some coordinates of the state of the system. An example is given to illustrate the obtained results.

ISSN:0020-7721    

DOI:10.1080/00207729308949469

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Although stabilizability properties of linear hereditary systems having point and distributed delays have been widely studied in the literature, an exhaustive characterization of the properties of controllability and observability has been established only for the first class of system. In this paper, results about stabilizability, controllability and observability concerning a wide class of point delay systems are extended to a class of systems involving distributed delays by building what is, in a sense, an equivalent augmented point delay system for the given distributed delay system.

ISSN:0020-7721    

DOI:10.1080/00207729308949470

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The general recursive parameter estimation problem of identifying unknown parameters subject to sequential observation is studied from the information theoretic viewpoint. The entropy theorem for the recursive estimation problem is first presented to give the upper and lower bounds of the reduction of the processed error entropy under sequential estimation. This result is then developed to yield the conditional entropy theorem; a lower bound on the conditional error entropy given past measurements is obtained. As an application of the conditional entropy theorem, recursive state estimation problems such as filtering, smoothing and prediction are investigated.

ISSN:0020-7721    

DOI:10.1080/00207729308949471

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The purpose of this study is to develop an economic growth model to explain dynamic interactions among physical capital accumulation, population adjustment, and human capital improvement. We assume that human capital can be increased by education and learning by doing. Population growth may be affected by knowledge and economic conditions. We examine the effects of changes on some parameters by traditional comparative static analysis under presumed stability. We also guarantee the existence of permanent oscillations when the system loses its stability due to shifts in the population adjustment speed parameter.

ISSN:0020-7721    

DOI:10.1080/00207729308949472

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Stability robustness in discrete-time multivariable feedback systems subject to noises and non-linear time-varying unmodelled dynamics is discussed. Based on the technique of functional analysis and the control algorithm advanced by Youlaet al., we derive a necessary and sufficient condition for robust stabilization as well as a closed-form solution to the problems of synthesizing optimal controllers that maximize the excess robustness to tolerate the unmodelled dynamics and noises. A necessary and sufficient condition for the solvability of such a robust stabilization problem is also introduced by means of Nevanlinna-Pick interpolation theory. In addition, an all-pass solution for the minimumH∞-norm problem is employed to treat our problems. Furthermore, neither the plant nor the controller has to be restricted to be stable or minimum-phase.

ISSN:0020-7721    

DOI:10.1080/00207729308949473

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

An adaptive decoupler for MIMO systems is implemented based on the system gains. Because of the adaptation feature, this decoupler gives better response with time varying systems, compared with fixed decouplers. When this decoupler is used with SISO adaptive controllers, the effect of parameter variations can be separated from the effect of disturbance.

ISSN:0020-7721    

DOI:10.1080/00207729308949474

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A novel method is presented capable of constructing rule-bases via self-learning for the use of fuzzy controllers. The controlled process is assumed to be a multivariable system with strong interaction within variables and with pure time delays in control. The objective of the proposed system is to build, in the case of two-input two-output systems, two separated and decoupled rule-bases for two control loops with some design requirements. The paper is divided into two parts. In the first part, a system structure comprising four functional modules is proposed. Then, the paper focuses on the issues concerning the learning algorithm. By introducing learning errors, three learning update laws are suggested. Furthermore, the convergence property of the learning algorithms is analysed in the sense of some defined norms. In addition, some comments and remarks about the proposed algorithms are given. The second part of the paper deals mainly with the issues of the methodology for rule-base formation and the application to the problem of multivariable control of blood pressure.

ISSN:0020-7721    

DOI:10.1080/00207729308949475

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

While the first part of this paper was concerned primarily with the issues of system structure and associated learning control laws, the second part presents a methodology for constructing the rule-base from learned data. The approach, based on a simplified fuzzy control model, is systematic, simple but efficient. The proposed system is applied to the problem of multivariable control of blood pressure, which is characterized by strong interactions and pure time delays in controls. It is shown that the effects of loop interaction are removed automatically by the learning scheme so that a decoupled control structure can be built. Moreover, the problem of pure part delay is easily tackled due to the iterative property. By defining some performance measures such as AD, RD, FRD and IP, the behaviour of the proposed system in terms of the learning ability (adaptability), reproducibility and robustness are evaluated through a number of simulation studies. Some important conclusions are drawn from these studies.

ISSN:0020-7721    

DOI:10.1080/00207729308949476

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

In systems analysis, uncertainties may exist in model parameters and input data. Those uncertainties can propagate through the analysis and generate uncertainty in the results. Grey systems theory offers a method for incorporating uncertainties into systems analysis. In this paper, a new method of solution for a grey linear programming (GLP) model is advanced. The GLP model allows grey messages concerning the model parameters and input data to be communicated into optimization processes and solutions. A new application field—grey systems analysis of water resource planning and decision making under uncertainty—is introduced, and a case study is reported of water quantity allocation and quality planning in a drainage basin area connected to a water delivery canal in Xiamen, China. The results indicate that the solutions derived are feasible for the study area. Sensitivity tests of the effects of grey inputs on grey outputs are reported. It is indicated that the grey degrees of the solutions increase along with increases of those of input grey coefficients. When the grey degrees of input grey coefficients increase from 10% to 15% and 20%, those of grey solutions increase from 18.76% to 35.00% and 82.35%, correspondingly. The test results indicate that the grey solutions (grey outputs) can reflect the effects of input grey messages.

ISSN:0020-7721    

DOI:10.1080/00207729308949477

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor