摘要:

AbstractIn this text of the 1993 Blackett Memorial Lecture, a critical assessment of the effects of electricity privatization in England and Wales is Undertaken, with a particular emphasis upon understanding the new economic and strategic forces in the market. This leads to some discussion of the type of modelling approaches that can provide insight into these processes. In particular, a key role for business simulation, alongside optimization methods and economic analysis, is identified as a basis for an effective regulatory framework to manage the transition to more efficient market competition. Emphasis is placed upon recognizing the impacts of risk and competition on the decision-making of the new companies in the market, and upon analysing the‘short-termism’, the‘dash-for-gas’, the demise of the coal industry, consumer prices and the nuclear issues in these terms.

ISSN:0160-5682    

DOI:10.1057/jors.1994.55

出版商:Taylor&Francis    

年代:1994

数据来源: Taylor

摘要:

AbstractThere are essentially two schools of thought regarding the function of decision support systems. One is that the main purpose is to support the decision-maker in whatever style of decision-making he or she wishes. The other is that the support, while suiting the decision-maker's individual style, must also be based on an appropriate theoretical paradigm. The work with students of decision support systems reported here suggests that the latter, normative, view is not one which comes naturally to many of the students, even when working on an example where it seemed relatively easy to incorporate. Other conclusions are also presented, relating to the choice of software for decision support system development, the process of teaching about decision support systems, and group formation.

ISSN:0160-5682    

DOI:10.1057/jors.1994.56

出版商:Taylor&Francis    

年代:1994

数据来源: Taylor

摘要:

AbstractBritish Rail will operate direct high-speed freight train services between Britain and the Continent when the Channel Tunnel opens in 1994. The production of a train plan for these services can be formulated as a multi-objective combinatorial optimization problem. This paper describes the problem and gives details of the heuristic algorithm used for its solution.

ISSN:0160-5682    

DOI:10.1057/jors.1994.57

出版商:Taylor&Francis    

年代:1994

数据来源: Taylor

摘要:

AbstractThe construction of a model of the UK Government bond market, the gilts market, is described. The model uses discount functions, represented by low degree polynomials in the form of B splines, to estimate the theoretical price of each gilt. A demonstration of the use of the model for trading gilts is given and shown to be profitable. The gilt market is one of the more important fixed interest bond markets and the feasibility of extending the use of the model to other markets, for governmental bonds and eurobonds, is explored.

ISSN:0160-5682    

DOI:10.1057/jors.1994.58

出版商:Taylor&Francis    

年代:1994

数据来源: Taylor

摘要:

AbstractRisk analysis tools have been used to help manage various projects. This paper describes a case study in which an extension to the stochastic project network model was developed for a risk analysis of an oil platform installation, quantifying the possible impact of the weather on the project's schedule. Examination of the weather data suggested the use of a Markov weather model combined with a separate residence time distribution for key states. The weather model was incorporated into the stochastic project network allowing the interactions of the various project uncertainties to be examined. While the weather introduced a significant additional risk to the project, analysis of management's options indicated that much of the risk might be avoided. In particular, the analysis quantified the benefits of scheduling the project start to take advantage of the seasonal variations and hiring heavy duty equipment to operate in more arduous conditions.

ISSN:0160-5682    

DOI:10.1057/jors.1994.59

出版商:Taylor&Francis    

年代:1994

数据来源: Taylor

摘要:

AbstractThe Connecticut Department of Transportation (ConnDOT) was charged with investigating the possibility of reducing costs by operating with fewer than 13 equipment repair facilities. Using a mixed-integer programming model, we helped ConnDOT identify options for achieving savings without sacrificing quality of service. A key feature of the model is that it establishes repair capacities based on the past performance of benchmark facilities within the system. As we developed recommendation, we gave serious consideration to factors outside the context of the model and to feedback received from ConnDOT personnel. Ultimately, we proposed two options-one containing ten facilities and the other 11. The net present values of savings offered by these options are estimated at over $5.0 million and $3.1 million, respectively. While the 11-facility option is lower in savings,it has advantages in that it: (1) satisfies concerns highlighted by ConnDOT Maintenance; (2) is easier to implement than the ten-facility option; and (3) represents less of a current commitment, which is beneficial if future consideration of additional changes is likely. These advantages contributed to the 11-facility option being the one most widely preferred within ConnDOT.

ISSN:0160-5682    

DOI:10.1057/jors.1994.60

出版商:Taylor&Francis    

年代:1994

数据来源: Taylor

摘要:

AbstractThis paper deals with theGIx/G/cqueueing system in a steady state. We refine a diffusion approximation method incorporating the constraint of traffic conservation for general queueing systems. An approximate expression for the distribution of the number of customers is obtained. Numerical results are presented to show that the refined model provides improved performance.

ISSN:0160-5682    

DOI:10.1057/jors.1994.61

出版商:Taylor&Francis    

年代:1994

数据来源: Taylor

摘要:

AbstractThis paper presents an empirical comparison of three classification methods: neural networks, decision tree induction and linear discriminant analysis. The comparison is based on seven datasets with different characteristics, four being real, and three artificially created. Analysis of variance was used to detect any significant differences between the performance of the methods. There is also some discussion of the problems involved with using neural networks and, in particular, on overfitting of the training data. A comparison between two methods to prevent overfitting is presented: finding the most appropriate network size, and the use of an independent validation set to determine when to stop training the network.

ISSN:0160-5682    

DOI:10.1057/jors.1994.62

出版商:Taylor&Francis    

年代:1994

数据来源: Taylor

摘要:

AbstractIn this paper we study a procedure for finding bounds for the quadratic assignment problem. This procedure may be used as a sub-routine in hybrid procedures for solving this problem. The approach is based upon a data decomposition method, linking the actual data to the data of a special class of assignment problems for which bounds are computationally tractable.

ISSN:0160-5682    

DOI:10.1057/jors.1994.63

出版商:Taylor&Francis    

年代:1994

数据来源: Taylor

摘要:

AbstractIn this paper, we develop two new efficient heuristic procedures for the joint replenishment problem. Each of the two heuristic procedures generates iteratively a near-optimal replenishment policy starting with ordering frequencies that are derived from the solution to a relaxed version of the joint replenishment problem. Both heuristic procedures are illustrated with an example problem involving five jointly ordered items. Seven more illustrative problems, taken from the joint replenishment problem literature, are also solved to assess the cost performance of the two heuristic procedures. They both provide the global optimal replenishment policies for all the illustrative problems.

ISSN:0160-5682    

DOI:10.1057/jors.1994.64

出版商:Taylor&Francis    

年代:1994

数据来源: Taylor