摘要:

AbstractThe main purpose of this paper is to demonstrate a real-world application of pure integer programming to find the optimum solution to a labour cost problem. The length of a daily working shift is defined as an integer variable and several shift strategies are analysed to determine the optimum length and shift combinations that satisfy a predicted demand at minimum cost. The state-space model has been used to predict the stochastic behaviour of monthly demands for beer and soft drink. Savings of about 7% of the annual sales have been obtained as a result of implementing the integer programming approach. A numerical example shows that the solution obtained by rounding off the continuous optimal solution does not match with the integer optimal solution. It was also noted that if a rounded-off solution is feasible, then it provides an initial integer solution for the branch-and-bound algorithm that may reduce the computational time.

ISSN:0160-5682    

DOI:10.1057/jors.1995.20

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

AbstractThis paper discusses the development of a geographical information system (GIS) for analysing the spatial distribution of community-based health services and the patients who use them on the Wirral peninsula in North West England. Information, with full geographical coding, has been obtained about General Practitioners (GPs) on the Wirral and the services they provide, together with the location, age and sex of the patients registered with them. Data have also been assembled on the services provided at local clinics. This is augmented with information on administrative boundaries and the street network held in digital form, and with statistical information for small areas covering demographic structure, social conditions and deprivation. The GIS is being used to identify catchment areas for different services and to produce demographic, social and residential profiles for the patients who use them.

ISSN:0160-5682    

DOI:10.1057/jors.1995.21

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

AbstractA non-serial dynamic programming (NSDP) formulation, aimed at the decomposition and optimization of interconnected systems, is presented. A new model is proposed for the system decomposition. It is used to optimize an electrical distribution system, and the results on a 25-node network are reported.

ISSN:0160-5682    

DOI:10.1057/jors.1995.22

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

AbstractTotal Systems Intervention (TSI) is a very new approach to‘problem solving’, but has enjoyed a more extensive use than expected at this stage. Early accounts of it have now been explored in some depth in practice and through theoretical discussion. There have been many new insights generated. Conditions are now propitious for a thorough reworking of TSI as a practical tool, to bring it right up-to-date. This article provides a very brief review of uses of TSI, theoretical and practical reflections, plus an extensive overview of the TSI method as it is employed today. TSI's philosophy, principles and process are described and explained. Some ideas for further development are given.

ISSN:0160-5682    

DOI:10.1057/jors.1995.23

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

AbstractWe examine an LP/DEA-based technique for establishing an overall ranking of alternatives that are ranked on multiple criteria, which themselves are ranked. This two-stage process involves one LP in the first stage, and N LPs in the second stage to rankNalternatives. We find that the information fromN+ 1 LPs can be obtained by solving two LPs. In many cases, the solution of one LP, which can be done by inspection, is almost as informative as the two-stage procedure. We also indicate when the second stage would be redundant. If maximumtechnicaldiscrimination between the alternatives is sought, we consider how this might be achieved by aggressive cross-evaluation viaNLPs. We also show how to identify a subset of the alternatives that would be ranked in the first place under any ordering of the criteria, and thus play an important role in the evaluation procedure.

ISSN:0160-5682    

DOI:10.1057/jors.1995.24

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

AbstractIn choosing the best alternative with respect to multiple criteria, one approach is to estimate the criterion weights that influence the preferences of all the alternatives presented. When decision makers are able to make preference judgements based on the alternative as a whole, preference decomposition methods attempt to determine part-worths which represent the contribution of the criterion levels to the overall preference values. For each alternative, the sum of the part-worths estimates its overall preference value. In this work, we use linear goal programming to determine the part-worths of all the criterion levels. Simulation experiments are conducted to compare the performances of linear goal programming and ordinary least squares regression in preference decomposition and to examine the effectiveness of including constraints on the parameters. Our simulated results suggest that the linear goal programming model with constrained parameters has better predictive power.

ISSN:0160-5682    

DOI:10.1057/jors.1995.25

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

AbstractEfficient algorithms are availabe to solve the unconstrained assignment problem. However, when resource or budgetary restrictions are imposed, the problem becomes difficult to solve. We consider such a resource-constrained assignment problem and present a tabu search heuristic to solve it. Extensive computational results are presented which establish the superiority of the proposed algorithm over the existing algorithms. Our adaptation of tabu search uses strategic oscillation, randomized short-term memory and multiple start as a means of search diversification.

ISSN:0160-5682    

DOI:10.1057/jors.1995.26

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

AbstractFor the past decade, new techniques for production management–such as kanban (pull-through) systems, internal set-ups, zero inventory, etc–have gained tremendous interest. However, research indicates that the production environment is more important than specific techniques. One aspect of this environment is the production lead time. This paper examines the impact of lead time, in conjunction with the characteristics of the demand process, on costs through the use of a periodic-review production/inventory model with a non-stationary stochastic demand process. Our results indicate that costs are affected by a combination of production lead time and demand variances. While the demand means have no effect on costs, both the shapes of the demand distributions and the relative magnitude of the penalty costs do have an effect.

ISSN:0160-5682    

DOI:10.1057/jors.1995.27

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

AbstractThis paper addresses two-stage flow shop scheduling with parallel machines at one stage. For finding a minimum makespan schedule, which is strongly NP-hard, some efficient heuristics have been proposed in the literature. In this paper we enrich the set of heuristics by introducing a few classes of heuristics, and show that the existing heuristics can be put into this classification scheme. Furthermore, we give a complete theoretical analysis of the worst-case performance of the classes. Some empirical evaluations and comparisons for the average-case performance of a few typical heuristics in the classes are also performed.

ISSN:0160-5682    

DOI:10.1057/jors.1995.28

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

AbstractThe usual procedure for obtaining the equilibrium probability distribution of the queue length in a queueing system is by constructing and solving the difference-differential equations. In this paper, a new approach for deriving the equilibrium probability distributions of the queue length in theM/M/1,M/Ek/1 andEl/Ek/1 queueing systems is presented, based on the generating function of the number of the minimal lattice paths. The proposed procedure obtains the equilibrium probability distribution more easily than the usual procedure, which solves difference-differential equations.

ISSN:0160-5682    

DOI:10.1057/jors.1995.29

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor