This paper considers a single machine scheduling problem with preventive maintenance. In many cases, a machine must be maintained after it continuously works for a period of time. But most papers in the literature ignore non-availability of the machine. For this reason, this paper studies the problem of scheduling processing of jobs and maintenance of machine simultaneously. The objective is to minimise total completion time of jobs. The problem is proved to be NP-hard in the strong sense. Three heuristic algorithms and a branch and bound algorithm are proposed. Computational experiments are done to evaluate the effectiveness of the algorithms.

A supply chain is a worldwide network of suppliers, manufactures, warehouses, distribution centers and retailers through which raw materials are acquired, transformed and delivered to customers. In recent years, a new system approach for managing the supply chain at the tactical and operational levels has emerged. It views a supply chain as composed of a set of intelligent (software) agents, who are responsible for one or more activities and interacting with other related agents in planning and executing their responsibilities. This paper presents a multiagent architecture of supply chain integration. Agents coordination using extended contract net protocol is discussed. Two types of bidding approaches, i.e., the customizing-type and webbing-type are introduced into the multiagent supply chain system. Finally, a heuristics and two programming models for the planning and coordination of demand-driven supply chains are suggested.

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