A Quantitative Reverse Logistics Model and Waste Application for Electronic Products Hua Song, Surya Liman, and Hong-Chao Zhang
Alex Abadi
Department of Industrial Engineering Texas Tech University Lubbock, TX 79409
[email protected]
Image Microsystems Inc. 9800 Metric Blvd., Suite 300 Austin, TX 78758
[email protected]
Keywords-reverse logistics; recycling; interactive objective optimization;environmental impact;cost
impacts by Eco-indicators methodology, it is also our goal to minimize them in the related processes in the reverse logistics system. There are two LP objective functions included in the proposed reverse logistics problem. One objective function is to minimize the cost, the other is to minimize the environmental impact. The decision variables are the quantity of computers that should be produced by the manufacturer, stored and transported to the DC and the retailer, demanded by the customers, gathered by the collector, refurbished back to the customers, the DC and the retailer, recycled by the recyclers, and the material copper recycled from different computer components.
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This paper proposes a quantitative reverse logistics system model and an application example on electronic products. An interactive heuristics algorithm is presented to solve the multiobjective optimization problems of the proposed reverse logistics system model. Reverse logistics systems no longer are confined to one-way product flows from manufacturers to consumers, but also deal with flows in the opposite direction. Environmental issues are considered in reverse logistics. Companies cannot avoid the responsibility of their pollution to the environment. Reverse logistics is the ideal selection and could provide a solution to the management problem of electronic product wastes and help to lower economic cost and improve environmental performance of the business.
An application examples using one type of computer products are presented in this paper to validate the proposed model. The computers are dismantled in the Advanced Manufacturing Lab of Texas Tech University. The required computer data is collected from the lab. The calculation of optimization objectives and decision process to find the most satisfied trade-off between economic costs and environmental impacts of the reverse logistics system are shown in this paper. We use the proposed interactive heuristic algorithm to solve this complicated LP optimization problem with the help of the commercial software LINDO package on a personal computer. We make a sensitivity analysis of final cost and environmental solutions to recycling policy - required rate of recycled copper in procured copper by the manufacturer. The relationship between the economic cost and environmental is also discussed. The validation of the presented algorithm used in the reverse logistics model is made by the comparison of the classical weighted method.
This research studies optimization decisions and constraints required by analyzing the reverse logistic model. A multiobjective optimization method is used in this research, since the optimization decision problems of the proposed reverse logistics model always have multiple objectives. Product manufacturing, distribution, returning, recycling, and other general activities through the reverse logistics system are discussed and modeled. A life cycle assessment method (Ecoindicator 99) is also developed to integrate environmental impacts into optimization processes. To solve the interactive and complicated optimization problems in reverse logistics systems, an innovative quantitative model is structured and developed. The reverse logistics system includes the Manufacturer, Retailer, Distribution Center (DC), Customers, Collector and Disassembly, and Recycler. We care about the reverse scenario of a product after its production, transportation, inventory, use, product refurbishing, disassembly, materials recycling, and waste disposals. The product flows and activities throughout the reverse logistics chain are described. The reverse logistics network is assumed to be fixed. The production rates, demand rates, all the costs (production cost, transportation cost, holding cost, collecting cost, recycling cost, disposal cost, etc), ratio of reused products are known and constant in the fixed cycle period. The environmental impacts should be calculated with Eco-indicator method referenced by Eco-indicator 99 Manual for Designers. Minimizing economic cost is chosen as one criterion. After evaluating and quantifying the environmental
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This paper focuses on the analysis and application of this quantitative reverse logistics model. The conclusions and directions for further research in reverse logistics are presented at the end of this paper. First, the proposed logistics models and its optimization results can provide a quantitative reference for the government to make regulations and public policies about the environmental issues of business. Second, they also can help the corporations analyze the operational and environmental scenarios and problems of their business networks and change their operation activities to satisfy the new market opportunities and public regulations. Finally, they may be used for industry to get possible chances of direct business profit with environmental concerns and waste management.
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