The p-median problem has been widely studied in the literature during the last decades especially its linear version. We propose a capacitated p-median problem with concave costs, in which the global cost incurred for each established facility is a concave function of the quantity q delivered by this facility. The unit distribution cost decreases with the increased quantity of output or demand ...

Generally ordering policies are done by two methods, including fix order quantity (FOQ) and fix order period (FOP). These methods are static and either the quantity of ordering or the procedure of ordering is fixing in throughout time horizon. In real environments, demand is varying in any period and may be considered as uncertainty. When demand is variable in any period, the traditional and st...

The purpose of this paper is to investigate how different types of demand structure affect firms’ optimal pricing and private copy protection (DRM) level of digital products. We construct a model where the equilibrium prices and protection levels are dependent upon the two parameters: public copy protection of digital products and degree of compatibility of DRM in terms of hacking technology. W...

A classical and important problem in stochastic inventory theory is to determine the order quantity (Q) and the reorder level (r) to minimize inventory holding and backorder costs subject to a service constraint that the fill rate, i.e., the fraction of demand satisfied by inventory in stock, is at least equal to a desired value. This problem is often hard to solve because the fill rate constra...

This paper deals with the single-item capacitated lot sizing problem with concave production and storage costs, considering minimum order quantity and dynamic time windows. This problem models a lot sizing where the production lots are constrained in amount and frequency. In this problem, a demand must be satisfied at each period t over a planning horizon of T periods. This demand can be satisf...

In this paper we compare two mechanisms to regulate a monopoly: fixing a price for the good or service, or fixing the quantity to be produced. We consider an environment of asymmetric information in which the regulated firm has private information about the demand it faces or its costs. We completely characterize the optimal mechanism in both case and compare their performance. The problem is s...

This paper describes how a monopolist manipulates the balance of quantity and quality in order to increase revenue when its customers treat quantity and quality as substitutes. This ‘skewing’ of quality depends on the characteristics of customer’s demand for quality. Customers differ in demand for quality, because they differ in either (i) their preferences and/or (ii) their time cost per unit....