摘要:

AbstractMaintenance painting of the exterior of buildings is discussed along with the results of a survey to determine its effectiveness. A model based upon the policy of adhering to a constant painting cycle over the building's life is developed. It is found that economic optional cycles with a socially acceptable period may exist, but are unlikely to be global optima. Different forms of objective cost function are investigated.

ISSN:0160-5682    

DOI:10.1057/jors.1976.2

出版商:Taylor&Francis    

年代:1976

数据来源: Taylor

摘要:

AbstractThe expected response time to a call for service (CFS) for a given configuration of police beats is developed. The effect of downtime calls on the response time to a CFS is determined. Consideration is given to both travel time and waiting time. Travel time and service time distributions are isolated. The model is valid for Poisson arrivals and arbitrary service time distributions. A probabilistic assignment policy is determined for each beat. The fraction of incoming calls arriving in beatkanswered by unitlis obtained. Pre-emptive priorities are allowed. Application to the Aurora, Illinois, Police Department is shown.

ISSN:0160-5682    

DOI:10.1057/jors.1976.3

出版商:Taylor&Francis    

年代:1976

数据来源: Taylor

摘要:

AbstractCellular simulation, a method of organizing simulation models to improve experimental efficiency, is described and shown to have the further advantages of reconciling the event based approach with the activity approach to simulation modelling and to have implication for modelling large systems.

ISSN:0160-5682    

DOI:10.1057/jors.1976.4

出版商:Taylor&Francis    

年代:1976

数据来源: Taylor

摘要:

AbstractA system which exhibits time-varying fluctuations in measures which describe its state and which comprises inter-dependent feedback loops is likely to be amenable to the modelling methods of system dynamics. The shipping industry is analysed from this point of view with the aim of identifying its dynamic characteristics and their causal mechanisms. Examples are given of observed dynamic behaviour within and between trade sectors.

ISSN:0160-5682    

DOI:10.1057/jors.1976.5

出版商:Taylor&Francis    

年代:1976

数据来源: Taylor

摘要:

AbstractA stochastic model for the description, prediction and control of wastage in hierarchically structured manpower systems is given in this paper. In the model we identify reasons for leaving. When the expansion of the organization slows down people start to leave faster; conversely when expansion increases wastage tends to decrease. Thus the probabilities of individuals leaving voluntarily are not static. In this paper we model the phenomenon relating rates of voluntary leavers with the concept of cumulative acceleration of the overall growth of the organization. Results of testing the model in two large British firms are given.

ISSN:0160-5682    

DOI:10.1057/jors.1976.6

出版商:Taylor&Francis    

年代:1976

数据来源: Taylor

摘要:

AbstractThe purpose of this study is to examine the relative efficacy of several promising heuristic approaches to a classic problem of component placement. Four "construction" and nine "improvement" algorithms were chosen for investigation and compared experimentally on a CDC 6400 computer. The improvement methods were selected to test some basic strategies of pairwise-interchanging of components and the construction procedures were chosen primarily to evaluate the effects of the quality of starting solution on the improvement methods. The algorithms were tested on 75 problems generated from the literature and compared with respect to the produced solution quality and CPU run-time requirements. A construction approach due to Graves and Whinston produced the best results, both when used to generate starting solutions for the improvement methods and when evaluated on its own merit against the improvement methods using other starts. Construction approaches have previously been regarded in the the past as relatively inferior techniques.

ISSN:0160-5682    

DOI:10.1057/jors.1976.7

出版商:Taylor&Francis    

年代:1976

数据来源: Taylor

摘要:

AbstractThis paper is concerned with the classical vehicle scheduling problem where a set of vehicles with known capacities are to service a known set of points with deterministic demands at least cost. An extension of previous work is developed and an algorithm is presented. Suitable computational experience with the procedure is provided for both the symmetric and the non-symmetric problems.

ISSN:0160-5682    

DOI:10.1057/jors.1976.8

出版商:Taylor&Francis    

年代:1976

数据来源: Taylor

摘要:

AbstractThe equipment replacement model with equal replacement intervals has been studied by a number of authors. When new equipment is identical to old equipment, it has been proved that an optimum policy involves replacement at equal intervals (the equal life assumption). However, when equipment is subject to technological change, no such proof exists.Since almost all equipment is subject to technological improvement over time, and since the assumption of equal lives vastly simplifies the analysis, such a proof is highly desirable. In the absence of a proof, authors have attempted to justify the equal life assumption as a good approximation to a correct solution. For example, Smith argues that the process of discounting makes future replacements less important and with gradual technological improvement an equal life policy is close to optimum. This paper shows that under the definition of technological change employed by most authors working on equipment replacement problems, it is unnecessary to assume that an equal life policy is optimum, rather the optimality of such a policy can be proven.

ISSN:0160-5682    

DOI:10.1057/jors.1976.9

出版商:Taylor&Francis    

年代:1976

数据来源: Taylor

摘要:

AbstractIt is assumed that a unit is either in operation or is in repair. When the main unit is under repair, spare units which cannot be repaired are used. In this system the following quantities are of interest: (i) The time distribution and the mean time to first-system failure, given that thenspare units are provided at time 0. (ii) The probability that the number of the failed spare units are equal to exactlynduring the interval (0,t], and its expected number during the interval (0,t]. These quantities are derived by solving the renewal-type equations.Two optimization problems are discussed using the results obtained, viz.: (i) The expected cost of two systems, one with both a main unit and spare units and the other with only spare units is considered. (ii) A preventive maintenance policy of the main unit is considered in order to minimize the expected cost rate. Some policies of the two problems are discussed under suitable conditions. Numerical examples are also presented.

ISSN:0160-5682    

DOI:10.1057/jors.1976.10

出版商:Taylor&Francis    

年代:1976

数据来源: Taylor

摘要:

AbstractThe method described in this paper is applicable to the batch processing industry where a batch of a product is packaged into several container sizes immediately after manufacture. A packaging set-up is required whenever the unpackaged product is packaged into a particular packaging size, and the packaging set-up cost for each size depends on the preceding size packaged. An example involving four packaging sizes has been solved to illustrate the method.

ISSN:0160-5682    

DOI:10.1057/jors.1976.11

出版商:Taylor&Francis    

年代:1976

数据来源: Taylor