摘要:

We analyze the interface between a supplier and an assembly facility, where direct shipments are made from one to the other. The final manufacturing step at the supplier involves multiple components produced on a single machine or production line. The assembly facility uses these components at a constant rate. The supplier incurs a sequence-independent setup cost and/or setup time each time the production line is changed over from one component to another. On the other hand, setup costs and times for the assembly facility are negligible. We consider two types of delivery cost: a fixed charge for each delivery, and a fixed-charge-per-truck cost.

ISSN:0740-817X    

DOI:10.1080/07408179508936724

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

We investigate the problem of simultaneously determining schedules for the production of several assembly components at a captive supplier and delivery of those components to the customer. We consider situations in which production economies of scale in the form of setup costs and/or setup times make it desirable for the supplier to produce in batches that are larger than the desired order quantity of the customer. The objective is to minimize the average cost per unit time of transportation, inventory at both the customer and the supplier, and, where applicable, setup costs.

ISSN:0740-817X    

DOI:10.1080/07408179508936725

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The design of inventory control policies for serial systems is a topic currently being explored by a number of researchers. Our goal -in two papers - is to synthesize and extend some of these efforts. We consider, simultaneously, four sources of variability in production lines - processing time variability, machine breakdowns, rework and yield loss - and show some similarities and differences in their effects on the performance of the line. In this paper we introduce an enhanced model that accommodates raw material and demand uncertainity and demonstrate that many of the sample path results obtained previously can be extended.

ISSN:0740-817X    

DOI:10.1080/07408179508936726

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

This paper continues our study of the design of inventory control policies for serial systems. Using simulation, we compare alternate control policies where a target of mean throughput has to be met under three different objectives - minimize the maximum inventory, minimize the average inventory and minimize the variance of the output - for balanced lines and lines with one bottleneck,

ISSN:0740-817X    

DOI:10.1080/07408179508936727

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

We consider the problem of scheduling the delivery of n products into a warehouse with limited space under the assumptions of continuous demands at constant rates, infinite horizon, and no backorders. The delivery schedule is described by a cyclic schedule with time-varying lot sizes. The order frequencies and the order sequence are assumed to be given. We formulate a linear program that determines delivery times relative to the cycle length to minimize the relative maximum space used and show that the optimal solution is characterized by filling the warehouse at each order. We bound the optimal solution by using a worst-case analysis and give conditions under which the linear program has the same optimal solution as a quadratic program that minimizes the holding cost. Under general conditions, we derive a bound on the cost penalty that results when using the optimal solution of the linear program as a solution to the quadratic program. Finally, we complete a solution to the nonlinear lot-sizing model by determining the best cycle length corresponding to the solution to the linear program and present a bound on a quality of this solution.

ISSN:0740-817X    

DOI:10.1080/07408179508936728

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Most inventory models dealing with spare parts assume independent part failures and hence one-at-a-time failure occurrences. In practice, for example when an aircraft engine undergoes repair, there is usually more than one part requiring replacement or repair; we denote this situation as ‘multiple failures’. In this paper we represent multiple failures in a continuous, infinite horizon, order-for-order spares replenishment inventory model with cannibalization. We derive exact expressions for the distribution function and the expectation of the number of backlogged jobs; approximations are also provided. The results can be used to optimize spares inventories, to evaluate the effects of correlated failures, and to model the impact of parts commonality.

ISSN:0740-817X    

DOI:10.1080/07408179508936729

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

An extension of a preemptive open-shop scheduling problem is introduced. All processing times are integral and in each period i there is a cost ci, for each task which is processed in that period. Finding a schedule with minimum total cost is shown to be NP-hard; some solvable cases are discussed; bounds on the cost of an optimum schedule are computed. Finally, a special case is studied, namely where each job has at most three tasks and each processor has to work on at most three tasks. It is shown to have theoretical complexity equivalent to the general case.

ISSN:0740-817X    

DOI:10.1080/07408179508936730

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A production/inventory system consisting of multiple stages in series with arbitrary processing times and with intermediate buffer inventories is considered. There is a finished product warehouse at which demand occurs for the finished products according to a compound Poisson process. Inventory levels of both intermediate and finished stocks are controlled by a continuous-review (R, r) inventory control policy. Production at a stage continues until the inventory level in the downstream buffer reaches its target value R. Once the inventory level drops to its reorder level r, the stage undergoes a set-up and production resumes. An approximation method is developed to obtain the steady-state performance measures of the system. Numerical examples are presented to show the accuracy of the proposed method.

ISSN:0740-817X    

DOI:10.1080/07408179508936731

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Input control plays a critical role in regulating the release of jobs into a production system, and thereby controlling the inventory levels. We model the input control decision as a bicriteria problem that requires the maximization of the sum of job release times subject to minimum total job tardiness. Although the primary objective addresses job completion delays, the secondary objective considers earliness and waiting times. We propose a solution method that decomposes the original problem into a bicriteria problem for thecriticaljobs and the maximum release time problem for thenoncriticaljobs. These problems are solved in an iterative manner as the set of critical jobs is repetitively updated until no further improvement takes place. Computational results show the effectiveness of the proposed method as well as the substantial improvement that can be affected in job release times, without adversely affecting the tardiness values, over an approach that considers the single objective of minimizing total tardiness. This result is of interest to an operating manager who is responsible for controlling work-in-process and finished goods inventory related costs in addition to meeting due dates effectively.

ISSN:0740-817X    

DOI:10.1080/07408179508936732

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The implementation of a new control-based forecasting system (SDF) in 1989–1991 at the Aviation Supply Office, Philadelphia, Pennsylvania, is documented. The philosophy, experience, principles and formulas are presented with results from three implementations.

ISSN:0740-817X    

DOI:10.1080/07408179508936733

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor