EURO WORKING GROUP ON ENVIRONMENTAL PLANNING
SESSIONS ORGANISED BY THE GROUP FOR THE IFORS 2002 CONFERENCE

Abstract: Choosing packaging material for dairy products and soft drinks is an interesting issue at the moment. Discussions arise on the costs impacts and environmental impacts of both one way packaging and reusable packaging. The aim of this article is to develop an evaluation tool providing costs and environmental impacts of the PC-bottle and the GT-packs in the dairy sector, considering forward and return flows. The evaluation tool enables the user to analyse the costs and environmental impacts of a supply chain with and without return flows using scenario analyses with respect to the use of various carrier types and the number of return loops.

Abstract: We look at the joint decision of product design and closed loop supply chain network design for a refrigerator. Optimisation occurs over the full product life cycle (from cradle to grave) by a multicriteria MILP model. There are three possible product designs, each has different cost and environmental functions. Demand occurs at regional warehouses in Europe, suppliers are also available at various locations in Europe. Location-allocation for forward and reverse facilities are optimised given a set of allowed locations, in combination with optimal product design. The model is run for different scenarios, e.g. for future EU legislation.

Abstract: We analyze hybrid manufacturing/remanufacturing systems with a long lead time for manufacturing and a short lead time for remanufacturing. We review the classes of inventory strategies for hybrid systems in the literature. These are all based on equal lead times. For systems with slow manufacturing and fast remanufacturing, we propose a new class. An extensive numerical experiment shows that the optimal strategy in the new class almost always performs better and often much better than the optimal strategies in all other classes.

Abstract: In fire fighting, time and effort required to control a fire increase if the beginning of the fire containment effort is delayed. Fire suppression strategies emphasize initial, direct and massive attack to the fire or containment of its perimeter within predetermined or natural barriers. Several demand-covering models have been proposed for deploying available fire fighting resources in proper positions so that a forest fire is attacked within a specified time limit. This paper considers the problem of scheduling a single fire fighting resource when there are several fires (igniting simultaneously) to be controlled. A model is proposed based on the concept of "deteriorating jobs".

Abstract: Scheduling problems appearing in the literature usually concern jobs with constant processing times. Recently, a particular class of problems, namely, scheduling problems where processing times are deteriorating over time has attracted considerable attention. In this paper we study a single machine scheduling problem, where defect items are reworked instead of getting scrapped, while jobs rework times are deteriorating over time. The deterioration function can be a general convex and growing function F (linear, exponential, polynomial etc.). A sequence policy minimizing the makespan is presented.

Abstract: Scheduling maintenance has attracted the attention of many researchers. In the case of preventive maintenance, a machine is usually supposed that breaks if it is not maintained for a long time. In this paper the scheduling problem of a maintenance facility that is responsible for the maintenance of n machines of a production system is considered. Each machine has an efficiency that deteriorates over time according to a known convex and growing function. The machines' efficiency is improved with maintenance. The objective is to find a maintenance sequence policy that optimizes the overall efficiency of the system.

Abstract: The role of Life Cycle Analysis in identifying and measuring the environmental impact of extended supply chains, i.e., chains involving both forward and reverse activities, is very important. In the final phase of Life Cycle Analysis, that is Interpretation, alternative policies may be ranked and opportunities for the reduction of the environmental burdens may be identified and valuated. The opportunities for improvement may be based either on Inventory Analysis or on Impact Assessment. For this purpose critical parameters have to be chosen and evaluated and sensitivity analysis be applied. In this paper decision-making tools, including mathematical models, are used for the evaluation, comparison and selection of alternative policies regarding supply chains planning. The proposed analysis is applied to the results of Life Cycle Analysis in the case of recovery of lead-acid batteries.

Abstract: Focusing on the case of used PCs, this paper describes a web-based system that enables users to delegate tasks related to returns management to software agents acting upon their interests. The system performs configuration detection and benchmarking of end-of-use PCs. The outcome of this process, carried out by a "trusted-third-party" agent, may then be exploited by the system's buyer-agents that act proactively to match return offers with their actors' (e.g., Original Equipment Manufacturers) collection requests. A multiple-criteria decision support tool for comparative evaluation of requests and recommendation about the optimal recovery optionhas been also integrated in the system's seller-agents.

Abstract: Life Cycle Analysis does not always manage to provide working answers to policy questions. For instance, there are several activities with serious impact (not necessarily emissions) on the environment, which are not taken into account. In addition, it adopts a descriptive approach, while a prescriptive approach may be more environmentally significant. In this paper, environmental principles and practices applicable to the planning of logistics networks (including reverse networks) are used as a reference in order to define assessment parameters to be included in effective models for the measurement of the environmental performance of supply chains.

Professor Costas Pappis
Coordinator