摘要:

Four lot-sizing heuristic rules are presented that are truly simple and at the same time independent of economic order quantity (EOQ) assumptions. These rules are tested and compared against the Wagner-Whitin rule, an optimization rule based on dynamic programming, through the use of computer simulation. It is found that under a variety of tested environments some of the heuristics, despite being naive, are surprisingly effective in reducing the total cost. It is suggested that material requirements planning should give more consideration to simple lot-sizing heuristics.

ISSN:0020-7721    

DOI:10.1080/00207728908910127

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The dynamics of the Koizumi-Kopecky growth model with international transfer of technical knowledge is re-examined. Attention is focused on the existence of stable limit cycles in the model which have been neglected. The existence of oscillations of the capital-labour ratio and fluctuations of the current dividend per capita near the equilibrium is proved.

ISSN:0020-7721    

DOI:10.1080/00207728908910128

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

An attempt has been made to incorporate density and time-dependent birth and death rates into the generalized birth and death process given by Kendall (1948). The probability generating function of the process has also been investigated. A simple method of estimating the parameters of the process has been illustrated in the text. The applicability of the method for predicting the population of India, starting from the several deterministic projection figures given for any base year, is also discussed in the text.

ISSN:0020-7721    

DOI:10.1080/00207728908910129

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

It is generally considered that a fault-tolerant system is composed of a hardware system and a software system. The present work assumes that a hardware system is composed of two units (processors). Two software maintenance policies depending on the priority maintenance for software are proposed. In particular, software maintenance policies are discussed by evaluating the (time dependent) transient solutions of the reliability measures. Formulating Markov process models for two policies, and calculating the reliability measures numerically, two software maintenance policies for the resulting reliability measures are compared.

ISSN:0020-7721    

DOI:10.1080/00207728908910130

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

In recent years the catastrophe theory, and in particular the singularity theory, has been utilized for analysing the multiplicity problem of a Continuous Stirred Tank Reactor (CSTR) caused by bifurcation of the equilibrium point due to a change in parameter values. Some important results, such as the existence of the winged cusp point, were obtained. In these works, the bifurcation of the equilibrium point due to the change in a single control parameter, such as the feed flow rate or the mean residence time, was investigated. Also, the fixed-parameter space was divided into subsets characterized by different bifurcation modes. In the present work, the heat transfer coefficient is added to the feed flow rate as another control parameter and the bifurcation set of the equilibrium point in the two-dimensional control-parameter space is determined. In consequence, the dimension of the fixed-parameter space is reduced by one and the classification of the bifurcation modes in the fixed-parameter space is greatly simplified. A clearer insight into the multiplicity problem is obtained, together with some new results.

ISSN:0020-7721    

DOI:10.1080/00207728908910131

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor