İşbirlikçi olmayan envanter oyunları üzerine makaleler

In this thesis we study different non?cooperative inventory games. In particular, we focus on joint replenishment games and newsvendor duopoly under asymmetric information. Chapter 1 contains introduction and motivation behind the research. Chapter 2 is a preliminary chapter which introduce basic concepts used in the thesis such as Nash equilibrium, Bayesian Nash equilibrium and mechanism design.In Chapter 3, we study a non-cooperative game for joint replenishment of multiple firms that operate under an EOQ?like setting. Each firm decides whether to replenish independently or to participate in joint replenishment, and how much to contribute to joint ordering costs in case of participation. Joint replenishment cycle time is set by an intermediary as the lowest cycle time that can be financed with the private contributions of participating firms. We consider two variants of the participation-contribution game: in the single?stage variant, participation and contribution decisions are made simultaneously, and, in the two-stage variant, participating firms become common knowledge at the contribution stage. We characterize the behavior and outcomes under undominated Nash equilibria for the one-stage game and subgame-perfect equilibrium for the two-stage game.In Chapter 4, we extend the private contributions game to an asymmetric information counterpart. We assume each firm only knows the probability distribution of the other firms? adjusted demand rates (demand rate multiplied by inventory holding cost rate). We show the existence of a pure strategy Bayesian Nash equilibrium for the asymmetric information game and provide its characterization. Finally, we conduct some numerical study to examine the impact of information asymmetry on expected and interim values of total contributions, cycle times and total costs.In Chapter 5, we study a three?stage non-cooperative joint replenishment game. In this model, we assume that the intermediary is also a decision maker. In the first stage, each firm announces his contribution for the ordering cost. In the second stage, based on the contributions, the replenishment service provider determines a common cycle time that he can serve the firms. Finally, each firm decides whether to be a part of the coalition and served under this cycle time or act independently with an EOQ cost. We analyze each stage and give the conditions for equilibrium. We show that the subgame-perfect equilibrium cycle time is not unique. Although minimum and maximum cycle times that arise in equilibrium straddle the efficient cycle time, in general, whether efficient cycle time can be reached in equilibrium depends on the parameters of the joint replenishment environment. For symmetric joint replenishment environments, we show that whether efficient cycle time is a subgame-perfect equilibrium outcome depends only on the number of firms and is independent of all other parameters of the environment.In Chapter 6, we focus on finding a mechanism that would allocate the joint ordering costs to the firms based on their reported adjusted demand rates. We first provide an impossibility result showing that there is no direct mechanism that simultaneously achieves efficiency, incentive compatibility, individual rationality and budget-balance. We then propose a general, two-parameter mechanism in which one parameter is used to determine the joint replenishment frequency; another is used to allocate the order costs based on firms? reports. We show that efficiency cannot be achieved in this two-parameter mechanism unless the parameter governing the cost allocation is zero. When the two parameters are identical (a single parameter mechanism), we find the equilibrium share levels and corresponding total cost. We finally investigate the effect of this parameter on equilibrium behavior.In Chapter 7, we study the newsboy duopoly problem under asymmetric cost information. The market demand is initially split between two firms and the excess demand for each firm is reallocated to the rival firm. We show the existence and uniqueness of pure strategy equilibrium and characterize its structure. The equilibrium conditions have an interesting recursive structure that enables an easy computation of the equilibrium order quantities. Presence of strategic interactions creates incentives to increase order quantities for all firm types except the type that has the highest possible unit cost, who orders the same quantity as he would as a monopolist newsboy. Consequently, competition leads to higher total inventory in the industry. A firm?s equilibrium order quantity increases with a stochastic increase in the total industry demand or with an increase in his initial allocation of the total industry demand. Finally, we provide full characterization of the equilibrium, corresponding payoffs and comparative statics for a parametric special case with uniform demand and linear market shares.