摘要:

AbstractThis paper describes a discrete event simulation model for a solid-waste processing system which is to be installed in Zagreb, Croatia. The conceptual model was developed by activity cycle diagrams, and the computer model was developed using the program generation software package VS6. This paper describes the validation and verification of such a model, the design of simulation experiments and the selection of the system's configuration.

ISSN:0160-5682    

DOI:10.1057/jors.1993.22

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractThis paper describes a study carried out for the Social Services Department of a UK County Council towards the development of a system for the evaluation and prioritization of project-based work. There are three major components of the study; an activity analysis to investigate how managers in the department spend their time, with a view to establishing a time budget for the project work; a pilot study to introduce a simple system for project planning and workload balancing with a specialist team; and the development of a multiple criteria model for the evaluation and prioritization of projects. We envisaged a Decision Support System which integrated all of these elements; however, this was never developed; instead, the resultant benefits were of a very different nature. We reflect on the reasons for this and the implications for the success of the study.

ISSN:0160-5682    

DOI:10.1057/jors.1993.23

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractIn this paper we are concerned with the problem of sequencing a given set of jobs without preemption on a single machine so as to minimize total cost, where associated with each job is a processing time and a differentiable cost function defined on the completion time of the job. The problem, in general, is NP-complete and, therefore, there is unlikely to be an algorithm to solve the problem in reasonable time, thus a heuristic algorithm is desirable. We present two heuristic algorithms to solve the problem. The first algorithm is based on the differential of the cost functions, and the second algorithm is based on the least square approximation of the cost functions. Computational experiences for the case of quadratic, cubic, and exponential cost functions are presented.

ISSN:0160-5682    

DOI:10.1057/jors.1993.24

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractIn many problems involving efficiency analysis using DEA, certain factors may be measurable only on an ordinal scale. Specifically, it may be possible only to rank order the DMUs according to a factor, rather than being able to assign a specific numerical value of that factor to each DMU. To illustrate this, we examine a problem involving the evaluation of new technology installations. The presence of qualitative factors in such an environment motivates the need to investigate how such factors can be incorporated into existing efficiency measurement models. In particular, a procedure is presented for incorporating an ordinal factor into the DEA structure, with the resulting formulation being a particular form of cone ratio model. The model is then applied to the technology installation efficiency problem.

ISSN:0160-5682    

DOI:10.1057/jors.1993.25

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractCompressed workweeks have gained acceptance in many 7-days-a-week operations. This paper provides a multiple-shift workforce scheduling model and a simple algorithm for the 3-day workweek. The model presented here is of practical relevance and the algorithm is intuitive and simple enough to be implemented by hand. A scheduler planning to switch to a 3-day workweek but not certain how to schedule off-days and shifts, may find this paper helpful.

ISSN:0160-5682    

DOI:10.1057/jors.1993.26

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractDescriptive sampling has been shown to be a powerful method for obtaining variance reduction in discrete event simulation. This paper shows that the rewards of descriptive sampling can be easily obtained by modifying systems that currently use simple random sampling. The chosen example is a package that is structured using the three-phase modelling method. The requirements for an implementation are outlined, the particular needs of the chosen package described, and evidence provided that the implementation works.

ISSN:0160-5682    

DOI:10.1057/jors.1993.27

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractA production system operates at a speed which is a stationary stochastic process. Given the routine control point, the actual accumulated production observed at that point and the deterministic rate of demand, the decision-maker determines the timing of the next control point. The problem is applied to semiautomated production processes where the advancement of the process cannot be measured or viewed continuously, and the process has to be controlled in discrete points by the decision-maker. Since the cost of performing a single control is relatively high, the control should be carried out as rarely as possible but it also has to ensure a preset confidence probability of achieving production output no less than that required. Formulae for determining the next control point for an arbitrary distribution function of the stationary process with a certain autocorrelation function are presented. They depend on the status of the system (shortage or surplus), the relation between the rate of demand and the mean value of the speed, the variance of the speed, and on the confidence level 1-α. A practical numerical example from the mining industry will be given.

ISSN:0160-5682    

DOI:10.1057/jors.1993.28

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractThis paper examines the problem of determining the timing and frequency of inspection for n operations that form a manufacturing process. The problem is formulated as a non-linear integer program with the restriction that the frequencies are power-of-two. The restriction is very practical from an operational viewpoint and will not increase the total annual inspection cost by more than 6%. A worked example is presented to illustrate the algorithm used to solve the problem.

ISSN:0160-5682    

DOI:10.1057/jors.1993.29

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractWe investigate the application of Benders' partitioning to a mixed integer programming formulation of the segregated storage problem. The dual subproblem reduces to an efficiently-solvable network flow problem. This approach is compared empirically to Neebe's multiplier adjustment procedure. Benders' procedure is shown to be computationally effective for an important class of practical applications having high demand-to-capacity ratios and fewer products than compartments.

ISSN:0160-5682    

DOI:10.1057/jors.1993.30

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor

摘要:

AbstractThis note considers the joint replenishment inventory problem for N items under constant demand. The frequently-used cyclic strategy (T;k1,…,kN) is investigated: a family replenishment is made every T time units and item i is included in eachkith replenishment. Goyal proposed a solution to find the global optimum within the class of cyclic strategies. However, we will show that the algorithm of Goyal does not always lead to the optimal cyclic strategy. A simple correction is suggested.

ISSN:0160-5682    

DOI:10.1057/jors.1993.31

出版商:Taylor&Francis    

年代:1993

数据来源: Taylor