Journal of the Operational Research Society

Kirby, M; Capey, R

doi: 10.1057/palgrave.jors.2600420pmid: N/A

AbstractThis paper analyses the origins and implementation of British bombing policy with regard to Nazi Germany from an operational research perspective. It demonstrates that the campaign of area attack on the German civilian population, inaugurated by Bomber Command in 1942, was validated in part by the misapplication of operational research, leading to a strategic air offensive, of limited value both in terms of its impact on the German war economy and on the morale of industrial workers. The article also emphasises that on the two occasions on which Bomber Command's resources were diverted from area attack in favour of precision targets (the anti-U Boat war and Operation Overlord), the views of civilian operational researchers had proved decisive. Finally, the article raises the issue of the effectiveness and independence of Bomber Command's Operational Research Section in the face of the entrenched views on bombing policy held by the Commander-in-Chief, Sir Arthur Harris.

Zanakis, S H; Zopounidis, C

doi: 10.1057/palgrave.jors.2600401pmid: N/A

AbstractThis case study evaluates the financial features of Greek firms that were taken over during the period 1983–1990. A sample of acquired firms and a sample of equivalent non-acquired firms are considered with the objective of distinguishing between them, based upon their differences in sixteen financial characteristics 1–3 years prior to each takeover. Linear and quadratic discriminant analysis and logit models are developed with factor analysis input. Prediction results are mixed, mainly due to the similar financial ratio profiles between acquired and non-acquired firms. Most models classify correctly a significant proportion of acquired or non-acquired firms, but not both (with one exception). The only model that provides significantly correct predictions for both acquired and non-acquired firms in either the calibration or holdout sample is a linear discriminant function with six financial ratios (two from each of the three years prior to takeover). The reasons for these modelling difficulties are discussed.

Christer, A H; Lee, S K

doi: 10.1057/palgrave.jors.2600424pmid: N/A

AbstractA ship is required to operate for a fixed mission period. Should a critical item of equipment fail at sea, the ship is subject to a costly event with potentially high risk to ship and crew. Given warning of a pending defect, the ship can try to return to port under its own power and thus attempt to avoid an at sea failure. Defects which lead to a failure are detected by inspection, and the task is to select the appropriate frequency of inspection to balance the number of occasions that a ship fails at sea and the number of preventive inspection based returns to port during a mission to correct a defect. The modelling entails using the delay time concept. Expressions are established for the expected number of preventive and failure returns over a mission, and an example given of a cost based balance to select an optimal inspection period. Although addressing ship reliability, the model has relevance to the mission reliability of any repairable equipment with remote main repair facilities.

Sani, B; Kingsman, B G

doi: 10.1057/palgrave.jors.2600418pmid: N/A

AbstractThe (s,S) form of the periodic review inventory control system has been claimed theoretically to be the best for the management of items of low and intermittent demand. Various heuristic procedures have been put forward, usually justified on the basis of generated data with known properties. Some stock controllers also have other simple rules which they employ and which are rarely seen in the literature. Determining how to forecast future demands is also a major problem in the area. The research described in this paper compares various periodic inventory policies as well as some forecasting methods and attempts to determine which are best for low and intermittent demand items. It evaluates the alternative methods on some long series of daily demands for low demand items for a typical spare parts depot.

Ringuest, J L; Downing, C E

doi: 10.1057/palgrave.jors.2600417pmid: N/A

AbstractMultiobjective linear programming algorithms are typically based on value maximization. However, there is a growing body of experimental evidence showing that decision maker behavior is inconsistent with value maximization. Tversky and Simonson provide an alternative model for problems with a discrete set of choices. Their model, called the componential context model, has been shown to capture observed decision maker behavior. In this paper, an interactive multiobjective linear programming algorithm is developed which follows the rationale of Tversky and Simonson. The algorithm is illustrated with an example solved using standard linear programming software. Finally, an interactive decision support system based on this algorithm is developed to field test the usefulness of the algorithm. Results show that this algorithm compares favorably with an established algorithm in the field.

Liu, Fuh-Hwa F; Hsiao, C-J

doi: 10.1057/palgrave.jors.2600426pmid: N/A

AbstractThe problem of finding an optimal loading layout for packing identical boxes onto a rectangular loading pallet is known as the pallet loading problem. If the boxes may be stacked on their bottom, side, or end surface, the cube utilization of a pallet will increase, but the stability of the unit load will be lost sometimes. This paper presents a method that packs rectangular boxes of the same size onto a pallet. Incorporating certain practical considerations, the method consists of five phases that maximise the degree of stability and the maximum cube utilisation of a unit load.

Cho, J-H; Kim, Y-D

doi: 10.1057/palgrave.jors.2600416pmid: N/A

AbstractThis paper presents a simulated annealing algorithm for resource constrained project scheduling problems with the objective of minimising makespan. In the search algorithm, a solution is represented with a priority list, a vector of numbers each of which denotes the priority of each activity. In the algorithm, a priority scheduling method is used for making a complete schedule from a given priority list (and hence a project schedule is defined by a priority list). The search algorithm is applied to find a priority list which corresponds to a good project schedule. Unlike most of priority scheduling methods, in the suggested algorithm some activities are delayed on purpose so as to extend search space. Solutions can be further improved by delaying certain activities, since non-delay schedules are not dominant in the problem (the set of non-delay schedules does not always include an optimal solution). The suggested algorithm is flexible in that it can be easily applied to problems with an objective function of a general form and/or complex constraints. The performance of the simulated annealing algorithm is compared with existing heuristics on problems prepared by Patterson and randomly generated test problems. Computational results showed that the suggested algorithm outperformed existing ones.

Ohlemüller, M

doi: 10.1057/palgrave.jors.2600409pmid: N/A

AbstractRecently it has been demonstrated that the use of simulated annealing is a good alternative for solving the minisum location–allocation problem with rectilinear distances compared with other popular methods. In this study it is shown that the same solution quality and a great saving of computational time can be achieved by using tabu search. It is also possible to transfer this method to location–allocation problems with euclidean distances.

Islam, A; Eksioglu, M

doi: 10.1057/palgrave.jors.2600412pmid: N/A

AbstractIn this paper, a tabu search approach is proposed for solving the single machine mean tardiness scheduling problem. Simulation experiment results obtained from the tabu search approach and three other heuristics are compared. Although computation time is increased, the results indicate that the proposed approach provides a much better solution than the other three approaches.

Gammerman, A

doi: 10.1057/palgrave.jors.2600381pmid: N/A