摘要:

AbstractThe visual interactive model is now a part of the toolbag of the operational research professional, and new applications are being reported regularly. This paper reviews the state of the practice of visual interactive modelling and attempts to identify successful application areas and opportunities for future developments.

ISSN:0160-5682    

DOI:10.1057/jors.1985.176

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

摘要:

AbstractIn repetitive judgmental discrete decision-making with multiple criteria, the decision maker usually behaves as if there is a set of appropriate criterion weights such that the decisions chosen are based on the weighted sum of all the criteria. Many different procedures for estimating these implied criterion weights have been proposed. Most of these procedures emphasize the preference trade-off among the multiple criteria of the decision maker, and thus the criterion weights obtained are not directly related to the hit ratio of matching decisions. Based on past data, statistical discriminant analysis can be used to determine the implied criterion weights that would reflect the past decisions. The most interesting performance measure is the hit ratio. In this work, we use the integer linear goal-programming technique to determine optimal criterion weights which minimize the number of misclassification of decisions. The linear goal-programming formulation has m constraints andm + k+ 1 variables, wheremis the number of cases andkis the number of criteria. Empirical study is done by using two different procedures on the actual past admission data of an M.B.A. programme. The hit ratios of the different procedures are compared.

ISSN:0160-5682    

DOI:10.1057/jors.1985.177

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

摘要:

AbstractOptimal scheduling of machine-service crew is an important issue in a manufacturing company. This paper discusses the use of two quantitative techniques, the mixed integer linear-programming approach and the queueing cost-analysis approach, to schedule the machine-service crew of an electronics manufacturing and testing company. Potential productivity improvement in the company is demonstrated by numerical results.

ISSN:0160-5682    

DOI:10.1057/jors.1985.178

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

摘要:

AbstractIn designing management information systems (M.I.S.), organizations tend to concentrate on computer-related issues, whereas research in M.I.S. has a behavioural tradition. This paper reports on the design and implementation of an M.I.S. for a bank, in which the key issues were to do with neither computers nor behaviour. The key issues concerned decisions and data. It was found to be important to analyse the decision-making system, to adopt an evolutionary approach to design, to reduce the data to manageable proportions, to format the data and to refine the data by use of techniques of management science.

ISSN:0160-5682    

DOI:10.1057/jors.1985.179

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

摘要:

AbstractThe Portuguese power-generation system includes a large set of hydro-electric power stations (with reservoir or run-of-river plants) which are responsible for about 58% of the total production (≃18,000 GWh during an average hydrologic year). Unfortunately, this hydro-electric contribution has a strong inter-annual variability (σ/μ= 3200/10,500≃0.3 GWh), and hence the annual cost of thermal production and imports, Ct, which is required can also cover a wide range of values.Smoothing {Ct} is important to avoid disturbing fluctuations of electricity rates, and the traditional solution to achieve this objective is that of increasing the inter-annual water storage capacity.However, this solution is bounded by hydrological and geographical limitations, and it requires a high level of capital expenditure.The purpose of this paper is to present another method to compensate the residual variation of {Ct} based on the development of a financial stock (‘Fundo de Apoio Termico-FAT’, or‘Thermal Contingency Reserve Fund’).A direct simplified analysis and a simulation model developed by the author to design this stocking system are presented in this paper, as well as their application to the case of Portugal.

ISSN:0160-5682    

DOI:10.1057/jors.1985.180

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

摘要:

AbstractThe job-shop due-date assignment problem arises when a manager needs to‘promise’a delivery date to a customer. Previous methods yield due-dates which are either optimistic (unlikely to be achieved) or conservative (the promise will be met, but too easily, because the date given was very pessimistic). This paper investigates the due-date assignment problem with a customer‘service-level’constraint, the percentage of time that promised delivery dates are honoured. We formulate a rule to attain this service level, yet maintain as short a due-date lead time as possible. Unlike previous attempts, this due-date rule considers not only the job content and instantaneous shop congestion information, but also implicitly incorporates information on how the jobs will be scheduled (or‘loaded’) once they are in the shop. We simulate a single-machine shop for various measures of performance under several dispatching priorities, comparing our due-date rule with one reported to yield satisfactory performance. Our rule meets all requirements and is found to be superior for most measures of performance.

ISSN:0160-5682    

DOI:10.1057/jors.1985.181

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

摘要:

AbstractThe inventory control problem can be vastly simplified if the replenishments of inventory items are coordinated with one another. That is, whenever an item is replenished,nother items, wherenis a decision variable, are also replenished. One way to ensure this would be to classify the inventory items into several groups with a common order interval for each group. In this paper we establish that the optimal groups will be consecutive byhD/A, whereh, DandAare the holding cost, demand rate and set-up cost of an item respectively. Using this property of consecutiveness, we develop a fast converging heuristic to create m groups optimally,m= 2, 3,...,M. The heuristic is a substitute for the dynamic programme which would otherwise be necessary and it has the potential for nomographic applications.

ISSN:0160-5682    

DOI:10.1057/jors.1985.182

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

摘要:

AbstractThere are many queueing systems, including theMx/My/cqueue, theGIx/M/cqueue and theM/D/cqueue, in which the distribution of the queue length at certain epochs is determined by a Markov chain with the following structure. Except for a number of boundary states, all columns of the transition matrix are identical except for a shift which assures that there is always the same element occupying the main diagonal. This paper describes how one can find the equilibrium distribution for such Markov chains. Typically, this problem is solved by factorizing of a certain expression characterizing the repeated columns. In this paper, we show that this factorization has a probabilistic significance and we use this result to develop new approaches for finding the equilibrium distribution in question.

ISSN:0160-5682    

DOI:10.1057/jors.1985.183

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

摘要:

AbstractIt is assumed that activity durations in a PERT network are independent and normal random variables. A simple method of obtaining lower and upper bounds for the expected project completion time is described. The tightness of the bounds is examined for some numerical examples. A problem of applying the method in the case of non-normal distributions of activity times is also discussed.

ISSN:0160-5682    

DOI:10.1057/jors.1985.184

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

摘要:

AbstractResearch indicates that the economic order quantity is preferred to alternative techniques because it is less nervous to forecast errors. This paper attempts to establish that no statistical relationship exists between the size of forecast error and the performance of some lot-size techniques. A heuristic rule is also presented for deterministic demand. The rule does well on the examples considered and is shown to be more stable than E.O.Q.

ISSN:0160-5682    

DOI:10.1057/jors.1985.185

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor