D esigning a wideband code division multiple access (W-CDMA) network is a complicated task requiring the selection of sites for radio towers, analysis of customer demand, and assurance of service quality in terms of signal-to-interference ratio requirements. This investigation presents a net-revenue maximization model that can help a network planner with the selection of tower sites and the calculation of service capacity. The integer programming model takes as input a set of candidate tower locations with corresponding costs, a number of customer locations with corresponding demand for traffic, and the revenue potential for each unit of capacity allocated to each demand point. Based on these data, the model can be used to determine the selection of radio towers and the service capacity of the resulting radio network. The basic model is a large integer program and requires a special algorithm for practical solution. Our algorithm uses a priority branching scheme, an optimization-gap tolerance between 1% and 10%, and two sets of global valid inequalities that tighten the upper bounds obtained from the linear programming relaxation. The algorithm has been implemented in software for the AMPL/CPLEX system and an empirical investigation has been conducted. Using over 300 problem instances with up to 40 towers and 250 service locations, various combinations of algorithm settings have been evaluated. Using the recommended setting results in a design tool that generally runs in under 20 minutes on a 667 MHz AlphaStation.

The theory of incomplete contracts has been used to study the relationship between buyers and suppliers following the deployment of modern information technology to facilitate coordination between them. Previous research has sought to explain anecdotal evidence from some industries on the recent reduction in the number of suppliers selected to do business with buyers, by appealing to relationship-specific costs that suppliers may incur. In contrast, this paper emphasizes the fact that information technology enables greater completeness of buyer-supplier contracts through more economical monitoring of additional dimensions of supplier performance. The number of terms included in the contract is an imperfect substitute for the number of suppliers. Based on this result, alternative conditions are identified under which increased use of information technology leads to a reduction in the number of suppliers without invoking relationship-specific costs. Conditions are also identified when increased use of information technology leads to an increase in the number of suppliers.

The design of a cellular network is a complex process that encompasses the selection and configuration of cell sites and the supporting network infrastructure. This investigation presents a net revenue maximizing model that can assist network designers in the design and configuration of a cellular system. The integer programming model takes as given a set of candidate cell locations with corresponding costs, the amount of available bandwidth, the maximum demand for service in each geographical area, and the revenue potential in each customer area. Based on these data, the model determines the size and location of cells, and the specific channels to be allocated to each cell. To solve problem instances, a maximal clique cut procedure is developed in order to efficiently generate tight upper bounds. A lower bound is constructed by solving the discrete optimization model with some of the discrete variables fixed. Computational experiments on seventy-two problem instances demonstrate the computational viability of our new procedure.

Firms that set up electronic marketplaces to enhance their supply and/or distribution channels face challenges in attracting their competitors to participate. A major obstacle is the perception that the owner can unfairly exploit trading information for competitive advantage. In this paper, we propose a marketplace design that shifts the locus of control over trader privacy from the marketplace operator to each individual trader. We show how online transactions between trading partners can be conducted in total privacy, so that not even the marketplace owner/operator can exploit transaction information for strategic purposes. At the same time, our approach includes robust methods for transaction integrity and nonrepudiation, as well as posttransaction dispute resolution.electronic commerce, security, privacy, B2B marketplaces

Video on demand, Efficient bandwidth, Cournot competition, Market equilibrium,