ISSN:0160-5682    

DOI:10.1057/jors.1989.1

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

摘要:

AbstractCecil Gordon is not now a name to conjure with in operational research. If he is remembered, it is for his classic‘Planned Flying, Planned Maintenance’study during World War II. Yet in 1948 his prominence was such that the Athenaeum dinner party which led to the foundation of the OR Club (and subsequently Society) consisted of Blackett, Goodeve, Tizard-and Gordon. This paper reconstructs his life and work, focussing in particular on his attempts, in the Board of Trade and elsewhere, to establish operational research within the civilian government machine. There are lessons to be learnt from what he was trying to do (an alternative direction for OR?) and the reasons for its failure at that time.

ISSN:0160-5682    

DOI:10.1057/jors.1989.2

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

摘要:

AbstractThis paper examines three themes of modelling. Its primary concern is with the problem of representing uncertainty in models, while the issues of interactive computer modelling and the use of models as decision aids also receive some attention. These issues are addressed by way of a comparative analysis of three models of the acid-deposition problem which have been developed in recent years in the UK and USA. The design of these models and the methods employed to represent uncertainty are described. The strengths and weaknesses of these techniques, and the various unresolved issues which these models have highlighted, are discussed.

ISSN:0160-5682    

DOI:10.1057/jors.1989.3

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

摘要:

AbstractPolice patrol has been modelled extensively in the urban environment, but these urban models cannot usually be applied to rural settings. The length of travel times and the nature of calls for service in rural, wide-area, low-population regions demand special consideration. In this paper, we develop a Markov model that explicitly incorporates travel times and priority calls to analyse police patrol policies in rural areas. Results of the model using data from Washtenaw County, Michigan, USA, are given to show its utility.

ISSN:0160-5682    

DOI:10.1057/jors.1989.4

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

摘要:

AbstractReduction of unproductive work-in-process (WIP) inventory has been a subject of global concern lately. Detailed examination often reveals that such unproductive WIP is the result of a low manufacturing system reliability (MSR). The impact of poor MSR is felt all the more in industries where material cost constitutes a significant portion of the total manufacturing cost. Guided by these considerations, in this paper a case study is reported wherein an analysis has been made to assess MSR in a multinational switchgear industry located in Western India. The paper provides a few practical guidelines towards maintaining a certain level of MSR by suitably adjusting factors like utilization level of machines, utilization level of tools, tool down-time, mean production rate per tool, etc. Detailed sensitivity analysis on the simulation results has also been presented, which is believed to help substantially in decisions related to the finer adjustments of these factors.

ISSN:0160-5682    

DOI:10.1057/jors.1989.5

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

摘要:

AbstractIn a practical situation it is often difficult to determine the value of the shortage costs for use in in ventory-control systems. However, in cost-minimization problems including service-level constraints, shortage costs are implicitly prevailing. With the purpose of exploring these relations, a continuous review (Q, r) stock-control system is considered, where the order points and lot sizes are computed simultaneously. Instead of explicitly expressing the shortage cost in the objective function, it is taken into consideration through a service-level constraint. The shadow price of this constraint can in some sense be interpreted as the shortage cost corresponding to the requested service level. By changing the value of the service level, interesting relations between shortage costs and service levels can be viewed for different sets of other inventory parameters. In order to investigate the sensitivity for probabilistic variations in the input data, two different probability distributions are used to describe the lead-time demand.

ISSN:0160-5682    

DOI:10.1057/jors.1989.6

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

摘要:

AbstractIn this paper a heuristic model is presented for determining the ordering schedule when an inventoried item is subject to deterioration and demand changes linearly over time. While the optimizing model developed by researchers fixes the ordering interval and varies the ordering size, the heuristic permits variation in both replenishment-cycle length and the size of the order. As a result, the heuristic produces a better solution than optimizing models in the study presented here.

ISSN:0160-5682    

DOI:10.1057/jors.1989.7

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

摘要:

AbstractTriangles provide a valuable means of diagrammatically summarizing and understanding data upon triads. In this paper, various properties of the triangular representation of data are discussed. The paper focuses on data relating to parliamentary elections, and demonstrates that an analysis based on the use of transition matrices can be misleading, especially when based upon what is referred to as a‘proportional loss’model. A triangular presentation of voting data suggests an alternative analysis-namely, a model of uniform change. Finally, there is discussion of some of the consequent implications for the marketing strategy of individual political parties.

ISSN:0160-5682    

DOI:10.1057/jors.1989.8

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

摘要:

AbstractIn a recent paper, Quaddus presents a linear programming analysis for assigning an optimal due date tonindependent jobs. The criterion treated in the model is the minimization of total penalty cost, where, for each job, penalties are assessed on earliness, tardiness and due-date allowance. Quaddus considers job-dependent penalties, thereby generalizing models addressed by other authors, but neglects the sequencing aspect of the problem. As a consequence, the examples are not completely optimized. In this note we offer an alternative proof of the Quaddus result, without relying on duality theory, and we show how Quaddus' examples fall short of optimizing the total penalty.

ISSN:0160-5682    

DOI:10.1057/jors.1989.9

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

摘要:

AbstractSeveral variations of two-dimensional (workers x jobs) and three-dimensional (workers x jobs x machines) time- as well as cost-minimizing assignment problems, which arise owing to (i) precedence relations of some form among the jobs or (ii) capacity restrictions on workers/machines imposed by the requirement that the surplus resources have to be fully employed, have been considered in the literature. In this paper, an algorithm is presented for time-cost trade-off analysis which is applicable to any general pair of such constrained problems. The algorithm is also illustrated by a numerical example.

ISSN:0160-5682    

DOI:10.1057/jors.1989.10

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor