摘要:

AbstractA descriptive model of the equipment-replacement decision process is presented which is based upon a survey of companies. Of particular concern was the form of any modelling employed, and the extent of its influence on the actual decision. It appears that, for more costly items, criterion modelling of some type tends to be undertaken but is not influential in the decision process. This contrasts with the less costly items, where the trend is to utilize cost-modelling which subsequently is influential in the decision process. Comments are made upon what appear to be lost modelling opportunities indicated by the survey.

ISSN:0160-5682    

DOI:10.1057/jors.1987.84

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractThis paper assesses possible gains to be made from increasing forecast accuracy. It examines the financial return from improving passenger revenue forecasts for a small airline, both in theory assuming‘optimal’cash management and in practice using policies currently in operation in the firm. It concludes that the gains are unlikely to outweigh the costs, that greater returns are likely to be available through better cash management and that the nature of forecast errors must be considered along with their size.

ISSN:0160-5682    

DOI:10.1057/jors.1987.85

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractA tractor-trailer problem, with full load, from the class of combined routeing and scheduling problems is described. Distinctive features of the problem are: movements must be carried out within certain time windows; subsets of movements are linked in the sense that they must be executed in a certain order; and different priorities are attached to different movements. A new bidirectional sequential constructive heuristic is developed for the solution of this problem. The method constructs routes and schedules for the available tractor fleet. The algorithm attempts to minimize the total time for all the movements by minimizing the time taken up by unproductive movements (so-called deadhead) and waiting time between movements. Some practical aspects of the implementation of the approach are discussed.

ISSN:0160-5682    

DOI:10.1057/jors.1987.86

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractThis paper examines the problem of choosing an organization structure for decision-making for two-level organizations under various information conditions. Decentralized decision-making (DDM), centralized decision-making with reporting by division (CDRD), and centralized decision-making (CDM) are considered. The information conditions pertain to the observability of states and actions. It is shown that if the party not making the decisions can infer the choice of action from theex postknowledge of the state, then DDM and CDRD are essentially equivalent in that it is possible to devise optimal incentive schemes in both cases. If, however, the action choice cannot be inferred, then CDRD is at least as preferred as DDM by the centre (regulator). Ifex postobservation (or inference) of the state can be made only by the party making the decision, we show that the centre (regulator) prefers CDRD to DDM. For this case, we derive an incentive scheme which elicits truthful information from the division (regulated entity). Finally, the incentive schemes are applied to the problem of regulating an industry that pollutes the environment.

ISSN:0160-5682    

DOI:10.1057/jors.1987.87

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractIn this paper, thep-median andp-centre problems are generalized by considering the possibility that one or more of the facilities may become inactive. The unreliablep-median problem is defined by introducing the probability that a facility becomes inactive. The (p, q)-centre problem is defined whenpfacilities need to be located but up toqof them may become unavailable at the same time. An heuristic procedure is presented for each problem. A rigorous procedure is discussed for the (p, q)-centre problem. Computational results are presented.

ISSN:0160-5682    

DOI:10.1057/jors.1987.88

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractIt has been shown that it is possible to solve a minimax 0-1 programming problem by transforming the objective function coefficients and solving a minisum problem. This result is very useful for solving a‘hard’minimax problem when there exists a‘relatively easy’algorithm to solve the minisum problem. We discuss such problems and present a new transformation.

ISSN:0160-5682    

DOI:10.1057/jors.1987.89

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractMany modern manufacturing facilities use carousel conveyors for storage of work-in-progress, and automatic devices to place and retrieve items in and from the storage locations. The‘carousel conveyor problem’is directly related to the‘patrolling repairman problem’reported by others. In this paper, we extend the model to include a single robot serving two or more carousels. The approach makes use of known results for the patrolling repairman.

ISSN:0160-5682    

DOI:10.1057/jors.1987.90

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractWhen faced with a difficult combinatorial problem whose optimization may be prohibitively expensive, researchers frequently turn to the study of fast heuristic algorithms in an effort to guarantee near-optimal results. An important aspect in the evaluation of such an algorithm is the determination of its worst-case behaviour, relative to an optimization rule. We here focus attention on schemes for combining two or more heuristics so as demonstrably to improve the worst case that can occur. We survey successful, illustrative examples of suchcompositealgorithms, concentrating on problems of central significance from domains such as scheduling, packing and routeing. We also attempt to illuminate the conditions under which these strategies can be successful and why.

ISSN:0160-5682    

DOI:10.1057/jors.1987.91

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractBy constructing an analytic model of a stochastic tank duel, this paper provides a means for evaluating a number of key performance characteristics of duelling tanks. The model explicitly represents target detection and the time taken to acquire a target and fire, or reload and fire. Additionally, tacticalmanoeuvre and kill probabilities are included. The probability of each possible outcome of such a duel is derived as output from the model.

ISSN:0160-5682    

DOI:10.1057/jors.1987.92

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractThe Holt-Winters method has been found to be a simple, robust and accurate method of forecasting seasonal series, but Trigg-and-Leach extensions have not proved successful. This note shows the reasons for this, and develops a Holt-Winters method which is adaptive in the Trigg-and-Leach sense. Numerical tests suggest that it may be superior to non-adaptive Holt-Winters.

ISSN:0160-5682    

DOI:10.1057/jors.1987.93

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor