摘要:

Many complex assembly lines, such as those in the automobile industry, have dozens or hundreds of stations that are affected by customer-selected options on the jobs being assembled. The various options often require significantly different amounts of processing time, and the role of assembly line sequencing in this context is to smooth out the flow of work to each station. However, most assembly line sequencing algorithms developed for such situations cannot consider so many stations or options effectively. In this paper, we develop an analytical method to compute a criticality index for each station, which can be used to determine which stations are most important to include in an assembly line sequencing algorithm. We report computational results using actual industry data which indicates that substantial improvements can be obtained by selecting stations based upon this criticality index.

ISSN:0740-817X    

DOI:10.1080/07408179408966590

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

This research deals with the capacitated, multi-item, multi-stage lotsizing problem for serial systems by examining the performance of heuristics found effective for the capacitated multiple-product, single-stage problem. The items have proportional processing requirements across stages; that is, if item 1 requires twice the processing time of item 2 at one stage, it requires twice the processing requirements at all other stages. The single-stage heuristics included in the study are: Dixon/Silver, Lambrecht/ Vanderveken, the Dogramaci, Panyiotopoulos and Adam (both single and multi-pass), and different versions of the ABC heuristic of Maes and Van Wassenhove. These heuristics have been altered in two ways. First, they allow for the inclusion of me cost modification procedures developed by Blackburn and Millen. Second, the feasibility routines have been modified to work in multi-stage environments. Both modifications attempt to coordinate decisions made across stages concerning lotsizes.

ISSN:0740-817X    

DOI:10.1080/07408179408966591

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

We investigate the problem of choosing optimal lot sizes in assembly systems when component manufacturing or procurement yields, and possibly assembly yields, are random. For a single-period setting, we analyze two models. The first has components with identical yield distributions and costs, random demand and an imperfect assembly stage. We analyze this two-stage problem, and highlight the implications of the results for the single-stage case where the final product is just a set of good components. The second model is a single-stage system where components have non-identical yield distributions and costs. We analyze a two-component system with known demand, identify conditions for concavity, and derive the optimality conditions.

ISSN:0740-817X    

DOI:10.1080/07408179408966592

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

We consider the problem of determining a maximum throughput cyclic schedule for the operations of a material handling hoist in an automated electroplating line. The proposed algorithm applies a set of simple algebraic inequalities to derive candidate schedules and uses a branch-and-bound-based search process to identify the optimal one. Computational results with both benchmark and random test problems are presented.

ISSN:0740-817X    

DOI:10.1080/07408179408966593

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

In this paper, we analyze discounting decisions for a supplier with a group of homogeneous customers. We focus on two aspects: the gaming nature of the discount problem and the demand consideration in the process. We use a general quantity discount schedule and start with the Stackelberg equilibrium of the problem. It is shown that, for the seller to gain from quantity discount, he has to set up his quantity discount schedule such that the buyer will order more than his EOQ. Both the seller and the buyer can gain significantly from quantity discount. The incentive for discount is twofold: reducing inventory related cost and attracting more demand from the customers. In addition, quantity discount schedule can be very efficient in obtaining the maximum gain the seller and the buyer can possibly obtain together.

ISSN:0740-817X    

DOI:10.1080/07408179408966594

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The presence of Type I and Type II inspection errors may seriously affect the product quality. In this paper we incorporate them into the EMQ (Economic Manufacturing Quantity) model under the imperfect production system. We derive the expected total cost when the shift of the production process follows a general distribution and the inspection interval is arbitrary. The objective is to determine the optimal production cycle length and optimal inspection number while minimizing the total cost. Results for special shift distributions such as exponential and Weibull are established. Sensitivity analysis of the optimal production cycle length and analysis of the cost surplus for incorporating inspection errors under exponential shift distribution are also provided.

ISSN:0740-817X    

DOI:10.1080/07408179408966595

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A production/inventory system consisting of a single-stage facility producing multiple product types and a warehouse is considered. The demand process is assumed to be Poisson and the excess demand is backordered. Products have a priority structure and the processor is shared according to a switching rule. (R, r) continuous-review inventory control policies are used to start and stop production of each product. Production of a product continues until its target level is reached. Then, a switch-over takes place to the highest priority product among the ones that need the processor's attention. A set-up takes place every time a switch-over occurs. Both processing and set-up times are assumed to have arbitrary distributions. The number of switch-overs among the high priority products is restricted in case low priority products need attention. The objective is to obtain performance measures such as the average inventory and backorder levels as well as die probability of having a backorder upon arrival for each product. We develop an approximation procedure which emphasizes the characterization of the delay each product type experiences in receiving the processor's attention, once they place a request for it. The approximating arguments are based on independence assumptions.

ISSN:0740-817X    

DOI:10.1080/07408179408966596

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Operations of a typical metropolitan daily newspaper are studied, and a mathematical model is developed to minimize the total expected annual production cost of operations through choice of various controllable schemes. The identifiable heterogeneities within the system are exploited in a positive way. Varying sensitivity of customers to inclusion of the latest news, varying advertisers' desired distribution with in selected zones, and limited interest for die local news are handled by offering multiple editions of die newspaper. Production workload is also distributed between advance and live runs, allowing printing of only news-sensitive sections during live-runs. To reduce peak loads, the final selection of start and run times for sections of various editions during live-runs, are made around values prescribed by management.

ISSN:0740-817X    

DOI:10.1080/07408179408966597

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

This paper examines multi-stage serial just-in-time production systems that use kanbans as a means of communicating the production needs of each stage of operation. The kanban-controlled system is a linked-demand system. A recursive function is presented which computes the number of kanbans required for all stages of a serial production system. This function is used to compute a lower bound on the expected fill rate for an arbitrary kanban assignment.

ISSN:0740-817X    

DOI:10.1080/07408179408966598

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

In this paper we study a multi-echelon production/distribution system where the retail centers are allowed to replenish their inventory through a normal resupply channel or an expedited resupply channel by incurring an additional cost. An approximation scheme to find the operating characteristics of such systems is developed. The results of a numerical study indicate that significant cost savings can be achieved by using the policy suggested in this paper.

ISSN:0740-817X    

DOI:10.1080/07408179408966599

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor