摘要:

Results of a simulation study of the economics of frequency of rescheduling Material Requirements Planning (MRP) systems are presented for a single-product, two-stage system in which demand is uncertain. The results indicate that for systems with moderate demand uncertainty, frequent rescheduling to maintain customer service may be uneconomical when compared with the alternative of more stable schedules in conjunction with safety stock. This result arises primarily because the cost of “emergency” production setups which occur when rescheduling is frequent exceeds the cost of safety stock required to “protect” stable schedules.

ISSN:0740-817X    

DOI:10.1080/07408178508975317

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Given a situation in which a finite number of load curves occur with either known probabilities or over nonoverlapping fractions of time, the problem addressed herein is to conduct a marginal cost analysis for allocating to the various load curves, the capital costs of equipments used in an optimal capacity expansion plan. Such an allocation may be used, for example, in determining a marginal cost time-of-day pricing scheme. A recent paper solves this problem through a formal mathematical programming duality approach. The purpose of the present paper is to first demonstrate that closed form expressions for such marginal cost capital allocations can be readily obtained through an intuitive and insightful perturbation analysis, without any recourse to mathematical programming techniques. Hence, a practitioner can therefore more easily understand and interpret the available duality results. Furthermore, the analysis contained in this paper helps to unify and generalize some existing contributions in the literature, and sheds light on the extent of information contained in the so-called equivalent load duration curve. By way of this analysis, a new set of easier to use and more general capital cost allocation formulae are also obtained.

ISSN:0740-817X    

DOI:10.1080/07408178508975318

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Quantity discount schedules have been studied, in the past, from the retailer's, and not the supplier's, point of view. These studies address the problem of determining the economic order quantities for the retailer, given a quantity discount schedule set by the supplier. In this paper, this problem is addressed from the supplier's point of view, assuming that the retailer always uses his optimal order quantity. It is shown that under certain circumstances, quantity discounts could be of benefit to the supplier (and obviously to the retailer), even when retailer's demand is insensitive to price changes. An algorithm is developed to determine the optimal pricing policy for a linear quantity discount schedule. Numerical examples are provided, and sufficient conditions when no quantity discount should be offered are derived.

ISSN:0740-817X    

DOI:10.1080/07408178508975319

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

When fuel prices are projected to change over the planning horizon, a standard approach is to formulate a multiperiod capacity expansion model for a utility. However, multiperiod models are considerably larger and more cumbersome than a single period model. An alternative strategy is to develop a single period model whose optimal solution replicates the first period part of the multiperiod optimal solution. This allows the model builder to trade-off a more aggregate multiperiod model for a more detailed single period, rolling horizon model without increasing computational complexity. When and how this can be accomplished in a model of electric utilities is the subject of this paper.

ISSN:0740-817X    

DOI:10.1080/07408178508975320

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

In this note we present a simpler total cost model when the repair work on a group of machines is coordinated. We demonstrate that coordination of repair work may not be economically beneficial under the generally accepted conditions. We suggest an improvement in the solution procedure in order to consider coordinated as well as uncoordinated repair policies for a group of machines.

ISSN:0740-817X    

DOI:10.1080/07408178508975321

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

ISSN:0740-817X    

DOI:10.1080/07408178508975322

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor