摘要:

Earlier studies on production systems had indicated that the output is optimum when the less variable stages are loaded slightly more than the more variable stages. It is shown in this paper that this guideline is violated in systems consisting of a hyperexponential stage. From a comparative study of several two-stage systems it is shown that the unusual unbalancing behaviour of the hyperexponential distribution is due neither to its negative memory nor to any abnormality in the plot of its higher moments but to the fact that it is a composite distribution.

ISSN:0020-7543    

DOI:10.1080/00207548508904687

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Under Poisson order-arrival, this paper discusses the economics of job-shop production by a policy approach, and presents an operational basis for job shop control. The model consists of job orders with marginal profits, selection function with backlog, and a production centre with fixed capacity. For the two main policies, PSP and DSP, this model is formulated by semi-Markov decision processes, and the operation rate, mean shop-time and reward rate (including idle cost) are obtained. Finally, the relationship of ‘six order-selection policies is given, and the structure of optimal policies is suggested.

ISSN:0020-7543    

DOI:10.1080/00207548508904688

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

This paper concerns a study of the effects of using various priority scheduling rules for capacity management and shop floor control in an MRP production system. The results of the study show that the application of different priority rules does cause such a system to perform differently. The indications are that a practitioner could cause his MRP system to perform in a more desirable fashion by his choice of priority scheduling rules for shop floor control under various capacity levels.

ISSN:0020-7543    

DOI:10.1080/00207548508904689

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

This paper initiates a structure for analysing problems involved in sequencing the operations that must be performed by a robot to tend machines in a cell. The sequence of operations is shown to be important in determining the feasibility of assigning a robot to tend machines and achieve specified production rates. Various cases, defined by the parameters that describe the system, are identified and analysed. Optimal sequencing procedures are described for several fundamental cases. Models are developed to prescribe solutions in more advanced cases, and the computational complexity of these cases is defined.

ISSN:0020-7543    

DOI:10.1080/00207548508904690

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

This paper describes a study which investigated the influence that alternate operations might have on the performance of flexible manufacturing systems (FMS). An alternate operation might be directed, for example, to avoid a long queue and would, perhaps, be performed by a machine of leaser capability so that a time penalty would be incurred. Three schemes for implementing alternate operations within the hierarchical structure of the FMS are devised and test results are compared with the performance achieved using no alternate operations. Results show that alternate operations can reduce flow (cycle) time (and therefore in-process inventory) while increasing machine utilization. The most effective of the three schemes requires use of multiple levels of the control hierarchy, applying a linear programming model to prescribe production plans and adaptive control to implement the plans over time.

ISSN:0020-7543    

DOI:10.1080/00207548508904691

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The problem of optimal part routing in a flexible manufacturing system is solved by a network flow optimization approach. Mathematical methods which exploit the structure of the problem to generate manufacturing paths are outlined. Numerical examples show that the method produces routing policies which yield good results when applied to a simulation model of a flexible manufacturing system.

ISSN:0020-7543    

DOI:10.1080/00207548508904692

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Various authors propose the use of flow dominance in complexity ratings to evaluate the complexity of facilities layout problems, to determine the choice between computer algorithms and visual based methods for plant layout, and to decide on the particular layout configuration (line or process layout) to be installed. This paper examines critically past contributions and casts some serious doubts on the validity of the flow dominance concept and the related measures of layout complexity. It is shown that flow dominance does not serve its intended purpose and that the complexity rating factors suggested in the literature not only show serious problems with regard to their interpretability, but are largely unusable. Finally, the future work needed in this problem area is elaborated.

ISSN:0020-7543    

DOI:10.1080/00207548508904693

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

This paper deals with the problem of finding the order quantities, or cycle times, for the case of a multi-item inventory system with joint replenishment costs. The ordering cost is composed of a fixed cost independent of the number of items ordered and additional ordering costs dependent on the specific items ordered. Different solution procedures suggested for solving this problem are presented. A simulation program is developed comparing the effectiveness of these algorithms. One hundred and thirty two different settings, each consisting of one thousand examples, are analysed. Based on the simulation, two approaches are recommended for solving this problem.

ISSN:0020-7543    

DOI:10.1080/00207548508904694

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The purpose of this paper is to describe and demonstrate a quantitative procedure for evaluating alternative computerized manufacturing control software packages that are being considered for possible purchase. The procedure considers both quantitative factors (i.e. costs) and qualitative factors (i.e. vendor reputation) that should be considered in the evaluation process. The various evaluation factors and criteria are identified and a procedure for quantifying the factors in commensurable unite is described. The procedure is demonstrated via an example.

ISSN:0020-7543    

DOI:10.1080/00207548508904695

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A practical problem of significant importance for many manufacturing systems is machine interference. Interference is undesirable and unnecessary machine idleness that is caused by allowing one (or more) operator(s) to tend several machines. When the service demands of machines are not synchronized, both operators and machines can experience interference. Interference obviously decreases the productivity of a manufacturing system. Most interference models are designed to attempt to minimize the cost of interference, or simply the interference itself.

ISSN:0020-7543    

DOI:10.1080/00207548508904696

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor