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In the Dynamic Capacitated Plant Location Problem (DCPLP) the task is to find a time schedule and sizes for installing facilities at plant locations to minimize the discounted cost of capital expenditures over the planning horizon. The costs include setup costs for establishing facilities, volume dependent operational costs, and transportation costs for distributing demand from facilities to customers. We consider a class of the DCPLP in which the available facilities have finite capacities and the number of facility types is relatively small so that the expansion sizes cannot be modeled by continuous variables. The DCPLP is formulated as a combinatorial optimization problem that allows consideration of more than one fatality type and finds the optimum mix of facilities in each location. We describe an optimization algorithm for solving the DCPLP based on the Lagrangian relaxation technique. Algorithms for converting infeasible optimal solutions of the Lagrangian to a feasible solution of the DCPLP are presented. The procedure has been tested on both randomly generated and real-life based problems. Computational results indicate that the algorithm produces solutions within 3% of the lower bounds for a wide range of input data.

In this paper, we consider the problem of multicommodity flows in a ring network. Using necessary and sufficient conditions to ensure feasible linear and integral flows in the network, and the special structure of the ring topology, we construct efficient algorithms to route all the demands.

With operations extending from the east coast to Hawaii, GTE is the largest local telephone company in the United States. Even before its 1991 merger with Contel, GTE maintained more than 2,600 central offices serving over 15,700,000 customer lines. It does extensive planning to ensure that its $300 million annual investment in customer access facilities is well spent. To help GTE Corporation in a very complex task of planning the customer access network, GTE Laboratories developed a decision support tool called NETCAP that is used by nearly 200 GTE network planners, improving productivity by more than 500 percent and saving an estimated $30 million per year in network construction costs.

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