ISSN:0160-5682    

DOI:10.1057/jors.1983.135

出版商:Taylor&Francis    

年代:1983

数据来源: Taylor

ISSN:0160-5682    

DOI:10.1057/jors.1983.136

出版商:Taylor&Francis    

年代:1983

数据来源: Taylor

摘要:

AbstractThis paper is based on the results of experience within the System Dynamics Research Group at Bradford Management Centre of teaching methods of system description. A routine procedure for general system description has been developed which facilitates problem recognition, understanding and qualitative analysis.The approach, which is centred on a taxonomy of system dynamics modules, is described in detail and demonstrated through a practical ecological example.

ISSN:0160-5682    

DOI:10.1057/jors.1983.137

出版商:Taylor&Francis    

年代:1983

数据来源: Taylor

摘要:

AbstractThe problem of smoothing the demand for industrial gas when there are large tariff incentives for doing so is considered. Two cases are discussed:where the only control variables are the maximum hourly and daily flow rates;where, in addition, gas storage tanks can be installed to help smooth the demand.In case (a) an analytic solution to the problem of establishing the optimal hourly and daily maximum settings is derived. In case (b) the influence of the storage capacity on the demand distribution is analysed, and a method of solution is proposed. This can then be used, together with the solution for case (a), to establish the optimal number of storage tanks to install.These ideas are applied to the gas usage in a steel factory.

ISSN:0160-5682    

DOI:10.1057/jors.1983.138

出版商:Taylor&Francis    

年代:1983

数据来源: Taylor

摘要:

AbstractA detailed analysis on the effects of different overtaking rules upon scheduled and unscheduled urban bus services was carried out. The analysis used computer models, which were developed to simulate bus operation strategies with or without overtaking and possibly parallel loading.Permitting overtaking in unscheduled services was found to reduce the journey time of the buses but resulted in a higher degree of irregularity in the service. Scheduled services, in contrast, appeared to be more reliable when overtaking was permitted. In such services, permission for overtaking reduced the waiting times of passengers as a result of faster journeys and a more regular service.

ISSN:0160-5682    

DOI:10.1057/jors.1983.139

出版商:Taylor&Francis    

年代:1983

数据来源: Taylor

摘要:

AbstractThis paper deals with the optimal allocation of resources in the production of human capital; i.e. the stock of knowledge of students has to be maximized subject to a limited budget. The optimal training intensity over time is obtained using optimal control theory. Considering various types of production functions (of human capital), the question of whether resources should be concentrated in early grades or not is investigated. The results are illustrated in special cases where monotonicity results for the training intensity can be obtained. Also provided is an analysis of the problem where the budget is replenishable.

ISSN:0160-5682    

DOI:10.1057/jors.1983.140

出版商:Taylor&Francis    

年代:1983

数据来源: Taylor

摘要:

AbstractIn their recent paper, which was published in theJournal of the Operational Research Society, Cheshireet al.describe "A dual heuristic for vehicle scheduling". The authors claim, on the basis of 17 academic test problems from the vehicle scheduling literature, that "in most cases the new results are comparable with those of Foster and Ryan, whose technique showed improvements over all previous methods". But a careful examination of the relevant source materials shows that one subset of authors, which includes the authors mentioned here, forced possibly premature rounding upon intermediate results in their calculations. Thus the comparisons performed by Cheshireet al., and their conclusions, are suspect in principle. They are later shown to be rather misleading in practice.

ISSN:0160-5682    

DOI:10.1057/jors.1983.141

出版商:Taylor&Francis    

年代:1983

数据来源: Taylor

摘要:

AbstractA branch-and-bound algorithm for a two-machine scheduling problem by Grabowski is generalized to the case of an arbitrary number of machines. The lower bounds are obtained by the relaxation of the capacity constraints on the machines. An approach to strengthen these lower bounds is developed. Computational experience with 6-, 10-, 15-, 20-, 30-, 40-, 50-job problems is presented.

ISSN:0160-5682    

DOI:10.1057/jors.1983.142

出版商:Taylor&Francis    

年代:1983

数据来源: Taylor

摘要:

AbstractThis paper describes an interactive method for presenting a sequence of feasible sets of indivisible projects to a decision-maker. For each set as a whole, the decision-maker evaluates its utilities with respect to each of several attributes; the utilities are then combined to give a single utility for the set.A sequence of zero-one programmes is used to ensure that the only sets presented are those which are feasible and which are not contained in larger feasible sets. The sets are presented in descending order of size, and the presentation can be terminated by the decision-maker or by supplementary rules.The method for presenting sets can be used in other contexts in which complete enumeration of possible sets would otherwise be required.

ISSN:0160-5682    

DOI:10.1057/jors.1983.143

出版商:Taylor&Francis    

年代:1983

数据来源: Taylor

摘要:

AbstractA fractional resource allocation problem with S-shaped return functions and an affine cost function is considered. Properties of optimal solutions are derived, including conditions for certain allocations to be zero. Conditions are given for the determination of an optimal solution by concave approximations of the return functions; otherwise an error bound is obtained.

ISSN:0160-5682    

DOI:10.1057/jors.1983.144

出版商:Taylor&Francis    

年代:1983

数据来源: Taylor