摘要:

AbstractThis paper uses a culture perspective to examine the complementarist idea of combining hard, soft and critical methodologies in systems research. The culture perspective is adopted because it reminds us that all research is underpinned by socially constructed meanings that often severely constrain the range of options that are possible. It is particularly appropriate, therefore, in the context of a situation where systems researchers are being urged to develop their research capabilities in distinctive ways. The future prospects for complementarism are examined in relation to two major factors—its cultural‘content’, and the overall level of receptiveness to culture change in the systems community.

ISSN:0160-5682    

DOI:10.1057/jors.1995.178

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

AbstractThis paper describes an investigation into the delays experienced by ships waiting to pass through the Suez Canal. The main objective of the Suez Canal Authority (SCA) is to provide an attractive service to ship-operators, and in doing so to maximize the income received from canal tolls. Thus, SCA wishes to maximize the throughput of vessels, but also requires queueing delays to be held at an acceptable level. This paper quantifies both measures (throughput and delays), and illustrates how they are in conflict to some extent. The study is somewhat unusual in that it affords the opportunity to employ more than one OR technique (linear programming and queueing theory/simulation) in the quantification process. Some of the work reported was undertaken in a consultative capacity, and the remainder as part of an ongoing research programme.

ISSN:0160-5682    

DOI:10.1057/jors.1995.179

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

AbstractDiscrete event simulation is becoming an established tool in finite capacity scheduling. However, recent work on scheduling systems has concentrated on the development of different modelling approaches and tools, without proper examination of how they can be used to meet business objectives. This paper examines the role of scheduling in improving business performance and suggests possible considerations in the development and implementation of a finite capacity scheduler. It reviews the advantages and limitations of discrete event simulation as a modelling technique for scheduling, and argues the need for further research to develop more versatile tools. A simulation-based scheduling system incorporating bottleneck planning principles to maintain throughput with low inventory is described, as are the experiences gained during its implementation in a medium-sized press shop.

ISSN:0160-5682    

DOI:10.1057/jors.1995.180

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

AbstractThis paper addresses the problem of loading pallets with non-identical items, i.e. what has been called the‘Distributor's Pallet Packing Problem’. It concentrates on the situation where the consignment to be loaded cannot be accommodated on a single pallet. A greedy procedure for tackling this problem, which is based on a published approach for loading single pallets, is described and evaluated. Also discussed is a series of possible modifications of the basic method, whereby the pallets involved are packed simultaneously. A detailed performance analysis is undertaken. The paper concludes with suggestions for further work in this area.

ISSN:0160-5682    

DOI:10.1057/jors.1995.181

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

AbstractThis paper reviews some of the current approaches available for computing the demand quantiles required to plan the procurement of items with stochastic non-stationary demands. The paper first describes the stochastic single-item lot-sizing problem considered and then presents a practical solution approach based on a dynamic lot-sizing model. Three methods available to compute demand quantiles are then reviewed and a new procedure based on smoothed order statistics (SOS) is proposed. Finally, the behaviour of these estimation methods, when used to solve single-item lot-sizing problems with non-stationary stochastic demands, is studied by simulation.

ISSN:0160-5682    

DOI:10.1057/jors.1995.182

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

AbstractThis paper presents a unified approach to finding both the mean (the so-called renewal function) and variance of the number of renewals in continuous time. Basically, it deals with three mutually exclusive situations depending on whether the inter-renewal time distribution has a closed-form (i) rational Laplace-Stieltjes transform (L–ST); (ii) irrational L–ST or (iii) it cannot be represented by a closed-form L–ST. Explicit closed-form expressions are obtained (in terms of roots) for both the mean and the variance. Asymptotic expressions in terms of roots are also obtained for larget. Numerical results are discussed for a variety of inter-renewal time distributions and their accuracies have been checked against the well-known asymptotic results and also against other numerical results available in the literature. The method discussed here can be employed for a variety of other problems occurring in areas such as queueing, inventory and reliability. The real strength of the method lies in the fact that it gives excellent results particularly in cases (i) and (ii) mentioned above.

ISSN:0160-5682    

DOI:10.1057/jors.1995.183

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

AbstractThis paper considers the permutation flowshop scheduling problem with significant sequence dependent set-up times and develops a savings index heuristic algorithm to find an approximately minimum makespan schedule. The proposed algorithm determines the savings in time associated with a particular sequence and selects the sequence with the maximum time savings as the best heuristic solution. Computational experience indicating the effectiveness and efficiency of the proposed savings index heuristic algorithm are reported and discussed.

ISSN:0160-5682    

DOI:10.1057/jors.1995.184

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

AbstractChiu, in 1976, studied the economic design ofnpcharts for processes subject to a multiplicity of assignable causes. Chiu developed a two-step minimization procedure to obtain the three control variables, namely, the sampling interval, the sample size and the acceptance number. Although Chiu's two-step minimization procedure is simple, applicable and down to earth, it is rather inefficient and has some drawbacks. This paper presents an algorithm to overcome these drawbacks. The results and the execution times of all numerical examples show that the accuracy and the efficiency of the algorithm is reasonably good.

ISSN:0160-5682    

DOI:10.1057/jors.1995.185

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

AbstractTwo unit-speed searchers starting at 0 seek a stationary target hidden according to a known bounded symmetric distribution. The objective is to minimize the expected time for the searchers to return to 0 after one of them has found the target. We find a general optimality condition and use it to solve the problem when the target has a uniform, triangular, or truncated, exponential distribution. The problem has applications to parallel processing and to the optimal choice of drilling depths in the search for an underground mineral.

ISSN:0160-5682    

DOI:10.1057/jors.1995.186

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

ISSN:0160-5682    

DOI:10.1057/jors.1995.187

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor