摘要:

This paper addresses concerns of die management of a service parts organization for the realized service level[Pcirc], measuring parts availability (from shelf), being much lower than die prescribed service levelP. The diagnostic study suggested the potential causes were die inventory miscount and die non-inclusion of lead time variability in computing reorder points. Quantitative measures for the degradation in the service level are derived as a function of the level of inventory miscount and the lead time variability. The prevailing levels of inventory miscount errors and lead time variability are estimated for a service parts organization with 45,000 parts and annual sales volume of $65 million. The composite degradation in service levelPˆis computed when these causes are operating individually and jointly.

ISSN:0740-817X    

DOI:10.1080/07408179208964206

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The conventional approach for setting order quantities when prices change does not incorporate a present value analysis, and does not distinguish inventory storage costs from the cost of money. These factors cause optimal order quantities to be overestimated when prices are reduced by more man 30%. Following a present value analysis, this paper evaluates the relationship between optimal order quantity and the magnitude of the price change.

ISSN:0740-817X    

DOI:10.1080/07408179208964207

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A mathematical programming model is developed for the design of sampling plans under varying inspection errors. The model minimizes average lot inspection cost subject to a given outgoing lot quality. An efficient search method is developed and is compared to complete enumeration based on six varying error models. The method always finds a global optimum and its efficiency increases on the maximum sample size. For a set of test problems, the method has examined at most 3.63% of all sampling plans to find a global optimum. This study verifies that the assumption of constant error or no error must be reconsidered. Also, the fact that the sampling plan must be adjusted depending on the inspection error models is justified.

ISSN:0740-817X    

DOI:10.1080/07408179208964208

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Many companies are using Just-In-Time (JIT) control systems in their mixed-model multi-level production facilities. When scheduling these facilities the most important objective is to keep a constant rate of usage for every part used by the system. In this paper a mathematical model for scheduling these facilities is studied and techniques for determining good schedules are developed. Procedures for solving very large problems are given.

ISSN:0740-817X    

DOI:10.1080/07408179208964209

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

In this paper a multiperiod replacement model is developed in the context of an incremental implementation of flexible automation investments. The model takes into account die costs, benefits and effective utilization of several types of flexibility, in deriving optimal machine replacement sequences and cost-effective production plans during the transition and later periods.

ISSN:0740-817X    

DOI:10.1080/07408179208964210

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The issues of facility layout and bed allocation in health care settings are typically evaluated separately using very different model-based approaches. This paper describes a two-phase approach to the hospital layout problem that incorporates a number of considerations from typical layout models and methods used in determining bed allocations. The first phase involves a quadratic integer goal programming model that determines a configuration and recommended allocation of beds to hospital services. The detailed ramifications of the proposed layout are then evaluated in the second phase via a simulation model. The application of the optimization-simulation approach in a general purpose hospital is described.

ISSN:0740-817X    

DOI:10.1080/07408179208964211

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The accuracy requirements for auditing as prescribed by MIL-STD-1567A allow for summing short operations into a super operation of approximately 30 minutes to meet the ± 10% precision with a 90% confidence level. Several problems incurred by such a procedure can be avoided by proposed alternative procedures for recognizing the greater variability of short operations.

ISSN:0740-817X    

DOI:10.1080/07408179208964212

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Dynamic scheduling of manufacturing systems has primarily involved the use of dispatching rules. In the context of conventional job shops, the relative performance of these rules has been found to depend upon the system attributes, and no single rule is dominant across all possible scenarios. This indicates die need for developing a scheduling approach which adopts a state-dependent dispatching rule selection policy. The importance of adapting the dispatching rule employed to the current state of the system is even more critical in a flexible manufacturing system because of alternative machine routing possibilities and me need for increased coordination among various machines.

ISSN:0740-817X    

DOI:10.1080/07408179208964213

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

In this paper we present an optimal solution procedure for the single period stochastic plant layout problem. The procedure only requires solving a “deterministic” from-to flow matrix. This “deterministic” matrix is a weighted-average of all from-to flow matrices. Since it may be difficult to estimate the probabilities of occurrence of the various states of nature, we developed a simulation model to test the robustness of our approach. For over 26,000 problems examined, the average error of using our approach was very small, only about one-sixth of one percent.

ISSN:0740-817X    

DOI:10.1080/07408179208964214

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

We consider the problem of setting up transportation contracts for a just-in-time delivery system between a manufacturer and one of its suppliers. The usage of parts fluctuates over time, and if the needed parts do not fit into the contracted vehicle, arrangements are made for a simultaneous emergency shipment at premium rates. We pose die problem as one of minimizing the total expected cost of contracted and emergency shipments, and where appropriate, inventory holding costs. We derive some properties of the optimal solution and present solution procedures. Computational results and possible research directions are also discussed.

ISSN:0740-817X    

DOI:10.1080/07408179208964215

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor