In this paper we develop an inventory model, to determine the optimal ordering quantities, for a set of two substitutable deteriorating items. In this inventory model the inventory level of both items depleted due to demands and deterioration and when an item is out of stock, its demands are partially fulfilled by the other item and all unsatisfied demand is lost. Each substituted item incurs a...

For real world railroad networks, we consider minimizing operational cost of train schedules which depend on choosing different train types of diverse speed and cost. We develop a mixed integer linear programming model for this train scheduling problem. For practical problem sizes, it seems to be impossible to directly solve the model within a reasonable amount of time. However, suitable decomp...

In this paper, we address the problem of locating collection centers for a company that collects used products from product holders. Each product holder has an inherent willingness to return the product, and makes the decision on the basis of financial incentive offered by the company. We present a mixed-integer nonlinear facility location-allocation model to find the optimal locations, the opt...