The problem of nonpreemptively scheduling a set of rn partially ordered tasks on n identical processors subject to interprocessor communication delays is studied in an effort to minimize the makespan.A new heuristic, called Earliest Task First (ETF), is designed and analyzed. It is shown that the makespan wEx-generated by ETF always satisfies to Eq.. (2 1/n wopti) + C, where Wopti) is the optimal makespan without considering communication delays and C is the communication requirements over some immediate predecessor-immediate successor pairs along one chain. An algorithm is also provided to calculate C. The time complexity of Algorithm ETF is O(nm2).

Vendor-managed inventory (VMI) is a supply-chain initiative where the supplier is authorized to manage inventories of agreed-upon stock-keeping units at retail locations. The benefits of VMI are well recognized by successful retail businesses such as Wal-Mart. In VMI, distortion of demand information (known as bullwhip effect) transferred from the downstream supply-chain member (e.g., retailer) to the upstream member (e.g., supplier) is minimized, stockout situations are less frequent, and inventory-carrying costs are reduced. Furthermore, a VMI supplier has the liberty of controlling the downstream resupply decisions rather than filling orders as they are placed. Thus, the approach offers a framework for synchronizing inventory and transportation decisions. In this paper, we present an analytical model for coordinating inventory and transportation decisions in VMI systems. Although the coordination of inventory and transportation has been addressed in the literature, our particular problem has not been explored previously. Specifically, we consider a vendor realizing a sequence of random demands from a group of retailers located in a given geographical region. Ideally, these demands should be shipped immediately. However, the vendor has the autonomy of holding small orders until an agreeable dispatch time with the expectation that an economical consolidated dispatch quantity accumulates. As a result, the actual inventory requirements at the vendor are partly dictated by the parameters of the shipment-release policy in use. We compute the optimum replenishment quantity and dispatch frequency simultaneously. We develop a renewaltheoretic model for the case of Poisson demands, and present analytical results.vendor-managed inventory, freight consolidation, renewal theory

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In this paper, we study the problem of scheduling semiconductor burn-in operations, where burn-in ovens are modeled as batch processing machines. A batch processing machine is one that can process up to B jobs simultaneously. The processing time of a batch is equal to the largest processing time among all jobs in the batch. We present efficient dynamic programming-based algorithms for minimizing a number of different performance measures on a single batch processing machine. We also present heuristics for a number of problems concerning parallel identical batch processing machines and we provide worst case error bounds.

In most manufacturing and distribution systems, semi‐finished jobs are transferred from one processing facility to another by transporters such as automated guided vehicles (AGVs) and conveyors, and finished jobs are delivered to customers or warehouses by vehicles such as trucks. Most machine scheduling models assume either that there are an infinite number of transporters for delivering jobs or that jobs are delivered instantaneously from one location to another without transportation time involved. In this paper, we study machine scheduling problems with explicit transportation considerations. Models are considered for two types of transportation situations. The first situation involves transporting a semi‐finished job from one machine to another for further processing. The second appears in the environment of delivering a finished job to the customer or warehouse. Both transportation capacity and transportation times are explicitly taken into account in our models. We study this class of scheduling problems by analysing their complexity. We show that many problems are computationally difficult and propose polynomial or pseudo‐polynomial algorithms for some problems. Copyright © 2001 John Wiley & Sons, Ltd.

This paper considers minimizing the makespan in the 3-machine assembly-type flowshop scheduling problem. After problem formulation, we present a proof to show that the general version of this problem is strongly NP-complete. We then discuss a few polynomially solvable cases of the problem and present the solution algorithms. Next, a branch and bound solution scheme is suggested. Finally, three heuristics to find approximate solutions to the general problem are proposed and their error bounds are analyzed.flowshop, scheduling, assembly-type production

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