A Stackelberg Network Game with a Large Number of Followers

We consider a hierarchical network game with multiple links, a single service provider, and a large number of users with multiple classes, where different classes of users enter the network and exit it at different nodes. Each user is charged by the service provider a fixed price per unit of bandwidth used on each link in its route, and chooses the level of its flow by maximizing an objective function that shows a tradeoff between the disutility of the payment to the service provider and congestion cost on the link the user uses, and the utility of its flow. The service provider, on the other hand, wishes to maximize the total revenue it collects. We formulate this problem as a leader-follower (Stackelberg) game, with a single leader (the service provider, who sets the price) and a large number of Nash followers (the users, who decide on their flow rates). We show that the game admits a unique equilibrium, and obtain the solution in analytic form. A detailed study of the limiting case where the number of followers is large reveals a number of interesting and intuitive properties of the equilibrium, and answers the question of whether and when the service provider has the incentive to add additional capacity to the network in response to an increase in the number of users on a particular link.     

Privacy impact on generalized Nash equilibrium in peer-to-peer electricity market

We consider a peer-to-peer electricity market, where agents hold private information that they might not want to share. The problem is modeled as a noncooperative communication game, which takes the form of a Generalized Nash Equilibrium Problem, where the agents determine their randomized reports to share with the other market players, while anticipating the form of the peer-to-peer market equilibrium. In the noncooperative game, each agent decides on the deterministic and random parts of the report, such that (a) the distance between the deterministic part of the report and the truthful private information is bounded and (b) the expectation of the privacy loss random variable is bounded. This allows each agent to change her privacy level. We characterize the equilibrium of the game, prove the uniqueness of the Variational Equilibria and provide a closed form expression of the privacy price. Numerical illustrations are presented on the 14-bus IEEE network.     

Optimal warranties,reliabilities and prices for durable goods in an oligopoly

This paper addresses the problem of durable goods manufacturers in an oligopoly seeking optimal values for three decision variables: product warranty, reliability and price. Each firm seeks a warranty-reliability-price combination that maximizes expected profit subject to quite general constraints on the firm's decision variables. Warranty serves as a signal of product reliability, which is not observable by consumers. We present a game-theoretic model of warranty-reliability-price competition in such a market and examine Nash equilibria for this game. We show that under fairly general assumptions each firm can optimally set its warranty and reliability independently of price and competitors' actions. In addition, we show that optimal warranties and reliabilities are complementary, and we explore the impact of different market factors on the optimal warranty and reliability. Finally, we show that optimal warranties are longer and products more reliable when consumers are risk averse.     

Application of duopoly multi-periodical game with bounded rationality in power supply market based on information asymmetry

In the power market, each entity is not completely rational when generate strategy, and the market information held by each entity is not exactly the same. In this paper, duopoly power providers with different selling adjustment structures are simplified from the actual grid background, where one provider can sell part of its power to another at contract price to store the power. Each provider is trying to maximize its profit by adjusting its power selling strategy. The process of evolutionary game with multi-periods bounded rational is established. One provider adjusts its selling strategy through the multi-periods market price and another through its multi-periods marginal profit. The quantity of power sold by each provider will tend to Nash equilibrium and how information asymmetry affects the stability of Nash equilibrium is analyzed through comparing dynamic power selling with and without information asymmetry. Information asymmetry has a great impact on one provider but not another. The numerical simulations also show that the information asymmetry will increase the stability region of the system. Different adjustment suggestions are proposed for different providers when information asymmetry occurs.     

网络服务中基于流量的定价策略

本文分析了网络服务中带宽的类似公共产品使用和ISP与顾客间主从博弈，导致拥塞，接着证明基于流量的定价策略较之固定定价策略更能控制网络拥塞，随后在基于流量的定价策略下，分析了垄断的市场中社会总福利达不到最优，ISP间的竞争会增加顾客效用，最后指出社会总福利达到最优时的价格是一影子价格。     

Price oligopoly as a cooperative game

We consider an oligopolistic market as follows. In the market, one good is traded for money. Each oligopolist is a price setter and has the same linear cost function. Each buyer is a price taker and buys the good from oligopolists setting the lowest price. We formulate this market as a cooperative game, and consider two kinds of solution concepts, the core and a bargaining set of the game. First we show that in the monopolistic market, the core gives the monopoly price, but in the oligopolistic market, the core is empty. Second, we obtain the bargaining set of the oligopolistic market.     

基于在线评论的多个竞争制造商和零售商的产品定价策略

在线评论作为一种产品信息传播载体,越来越受到网上电商及消费者的重视,并在很大程度上影响消费者的购买决策。本文在多个竞争性制造商为在线零售商提供可替代性产品并通过零售商销售给网络消费者的电子商务环境下,研究在线评论信息如何影响网络消费者购买决策及在线零售商和制造商的定价策略。以neo-Hoteling模型为基础,构建了依赖零售渠道在线评论的消费者选择模型,并通过模型求解定量分析了二级供应链结构分散系统下在线评论对多个竞争性制造商及零售商最优决策的影响。得到当制造商基于评论制定最优定价策略时,在线评论对市场竞争强度没有影响,但决定潜在市场大小;各产品的均衡批发价及销售价按一定的比例随评论揭示的该产品与其他产品质量均值之差(正或负)增加或减少,评论信息通常会使制造商因好评而获利,由于评论增加了不同产品需求的不对称性,零售商因而具有更大的调价空间,往往通过提高(降低)占据有利(不利)评论的产品价格获得更高的利润。     

Competition among providers in loss networks

Communication networks are becoming ubiquitous and more and more competitive among revenue-maximizing providers, operating on potentially different technologies. In this paper, we propose to analyze thanks to game theory the competition of providers playing with access prices and fighting for customers. Considering a slotted-time model, the part of demand exceeding capacity is lost and has to be resent. We consider an access price for submitted packets, thus inducing a congestion pricing through losses. Customers therefore choose the provider with the cheapest average price per correctly transmitted unit of traffic. The model is a two-level game, the lower level for the distribution of customers among providers, and the upper level for the competition on prices among providers, taking into account what the subsequent repartition at the lower level will be. We prove that the upper level has a unique Nash equilibrium, for which the user repartition among different available providers is also unique, and, remarkably, efficient in the sense of social welfare (with a so-called price of anarchy equal to one). Moreover, even when adding a higher level game on capacity disclosure with a possibility of lying for providers, providers are better off being truthful, and the unique Nash equilibrium is thus unchanged.     

Advertising in a Differential Oligopoly Game

We illustrate a differential oligopoly game where firms compete à la Cournot in homogeneous goods in the market phase and invest in advertising activities aimed at increasing the consumers reservation price. Such investments produce external effects, characterizing the advertising activity as a public good. We derive the open-loop and closed-loop Nash equilibria, and show that the properties of the equilibria depend on the curvature of the market demand function. The comparative assessment of these equilibria shows that the firms advertising efforts are larger in the open-loop equilibrium than in the closed-loop equilibrium. We also show that a cartel involving all the firms, setting both output levels and advertising efforts, may produce a steady state where the social welfare level is higher than the social welfare levels associated with both open-loop and closed-loop noncooperative settings.     

Infrastructure security games

Infrastructure security against possible attacks involves making decisions under uncertainty. This paper presents game theoretic models of the interaction between an adversary and a first responder in order to study the problem of security within a transportation infrastructure. The risk measure used is based on the consequence of an attack in terms of the number of people affected or the occupancy level of a critical infrastructure, e.g. stations, trains, subway cars, escalators, bridges, etc. The objective of the adversary is to inflict the maximum damage to a transportation network by selecting a set of nodes to attack, while the first responder (emergency management center) allocates resources (emergency personnel or personnel-hours) to the sites of interest in an attempt to find the hidden adversary. This paper considers both static and dynamic, in which the first responder is mobile, games. The unique equilibrium strategy pair is given in closed form for the simple static game. For the dynamic game, the equilibrium for the first responder becomes the best patrol policy within the infrastructure. This model uses partially observable Markov decision processes (POMDPs) in which the payoff functions depend on an exogenous people flow, and thus, are time varying. A numerical example illustrating the algorithm is presented to evaluate an equilibrium strategy pair.     

消费者分布不均匀条件下的具有网络外部性的Hotelling模型

将交通流量分配技术和无穷维变分方法相结合,采用无穷维变分不等式刻画网络产品水平差异的模型,研究了消费者分布不均匀时,具有网络外部性特征的企业进行价格竞争的两阶段完全信息动态博弈问题.得到了厂商价格竞争均衡的存在性条件,分析了产品的网络外部性特征及单位运输成本对两个厂商竞争均衡情况的影响.     

Competitive Price Equilibrium with Consumer Reservation Utility

This paper studies a competitive price equilibrium in the market of a product category where consumers are homogeneous with a reservation utility below which they will not purchase the product. The impact of the reservation utility on the price equilibrium is of particular interest, because the reservation utility may change according to the business cycle and economic environments. Using multinomial logit model to describe market response, we study the comparative statics of the prices, profits and market shares of firms, each of which produces one brand in the product category, with respect to the reservation utility in the Nash equilibrium. It is shown that, as the reservation utility increases, the prices as well as the profits at Nash equilibrium decrease. Also, in the case of duopoly market, the firm with lower cost structure will increase its market share as the reservation utility increases.     

基于不同融资方式的双渠道供应链定价决策

针对由一个制造商和一个有资金约束零售商组成的双渠道供应链系统,利用Stackelberg博弈模型,研究零售商分别选择银行贷款和延迟支付解决资金约束问题时,不同定价方案中制造商和零售商的最优决策,分析零售渠道市场份额以及融资利率对决策结果的影响。研究表明:零售商的资金不足不会改变各参与方最优决策随零售渠道市场份额的变化趋势。在双渠道不统一定价方案下,若选择银行贷款,只有零售渠道市场份额较小且利率较高时,直销价格随利率的增加而增加;若申请延迟支付,零售价格和直销价格不受利率影响。在双渠道统一定价方案下,销售价格只有在零售渠道市场份额较低时随银行贷款利率的增加而增加,与延迟支付利率无关。     

考虑即时采购价格的物流服务供应链优化

物流服务市场的不确定性会影响物流服务供应链的服务水平和收益。在考虑随机即时采购价格以及基础物流提供商在正常情况和应急情况下具有不同物流能力投资成本的情形下,引入期权机制研究不确定市场环境下物流服务供应链的优化决策,以提高物流服务供应链柔性和降低市场不确定性带来的风险。构建物流服务供应链的期权契约模型,采用Stackelberg博弈理论和优化算法分析和求得物流服务集成商的最优期权采购和即时采购策略,以及基础物流提供商的最优物流能力投资策略。结果表明即时采购价格将影响基础物流提供商和物流服务集成商的决策。最后通过数值分析研究即时采购价格的不确定程度对物流服务集成商和提供商的优化策略和利润的影响。     

The risk and information sharing of application services supply chain

We study an application services supply chain consisting of one application service provider (ASP) and one application infrastructure provider (AIP). The AIP supplies the computer capacity to the ASP that in turn sells the value-added application services to the market. The market is characterized by a price-sensitive random demand. The ASP’s objective is to determine the optimal price of its service to the market and the optimal capacity to purchase from the AIP. The AIP’s goal on the other hand is to maximize its profit from selling the capacity to the ASP.     

随机需求下物流服务供应链订购策略研究

针对由单个物流服务提供商和集成商组成的物流服务供应链,基于集中化模式、纳什博弈模式和Stackelberg博弈模式三种典型模式,考虑市场需求随机且受服务质量缺陷承诺水平的影响,探讨物流服务供应链的订购与质量缺陷承诺策略问题。通过分析发现:物流服务质量缺陷承诺水平随着市场需求弹性系数的增加而递减,但其受物流服务集成商观测水平的影响却因合作模式不同而变化不一致;集中化模式下的物流服务订购量随着物流服务集成商观测水平或市场需求弹性系数的增大而递减,但在其他两种合作模式下物流服务订购量随着物流服务集成商观测水平或市场需求弹性系数的增加而增加;在三种模式下,物流服务供应链的整体利润随着市场需求弹性系数的增加而递减,但其受物流服务集成商观测水平的影响却因合作模式不同而变化不一致。     

Dynamic entry deterrence in the UK pathology services market

This paper describes work on a dynamic model of entry deterrence applied to the UK National Health Service (NHS) market for pathology services. The model, based on a game theoretical framework, is concerned with decision support applications. Presented in this paper is a case study analysis of a geographical region in which a provider of pathology services is concerned at the prospect of being exposed to competition from a new entrant. The incumbent provider may undertake strategic investments to create a stock of knowledge and goodwill with the intention of dissuading others from entering the market. The effect of a new entrant is modelled as perturbation of a pre-existing stable Nash-Cournot equilibrium in an oligopolistic market, and is influenced by market forces subject to Government regulation. The original contribution of this study is to identify the nature of these potential strategic investments and their interaction with cash flows. Recent historical data and managerial analysis are used to characterise market growth. An estimate of the incumbent provider's market share which is at risk can be found by examining the local geographical distribution of providers and purchasers of pathology services. On the basis of this analysis we propose a method for obtaining the strategic investment profile which minimises the total investment required to deter entry.     

Dynamic oligopoly pricing with reference-price effects

We analyze the strategic implications of consumers’ reference-price effects, either symmetric (for loss-neutral consumers) or asymmetric (for loss-averse consumers), in a differentiated oligopoly model where firms compete either in prices (à la Bertrand) or in quantities (à la Cournot) over an infinite time horizon. The dynamic game is specified in continuous time. The solution concept is Markov Perfect Equilibrium. We show how price dynamics in the presence of reference-price effects crucially depends on the nature of market competition. One of the main results of our analysis is that, with loss-averse consumers, there exists an interval of initial reference prices such that firms adopt the same constant-pricing strategy in both the Bertrand and the Cournot games, implying that the distinction between price and quantity competition has no impact on market conduct and performance.     

Market share in a post-entry game

This paper investigates the dynamics of market share within a contemporary, real life, entry deterrence situation in the provision of National Health Service (NHS) pathology services. The major conclusion is that the previous Government's initiatives did not succeed in promoting competition in markets where existing NHS providers were operating significantly more efficiently than their neighbours. Evidence suggests managers were influenced more by potential competition from a new private sector entrant than by actual competition among existing providers. The effect of a new entrant is modelled as a perturbation of a pre-existing stable equilibrium in a seeming oligopoly influenced by market forces subject to Government regulation. Economic analysis of the market share which a new entry might gain shows that, on the assumptions made and contrary to expectations, the likely impact of Government regulation of NHS prices would be an increase in price per test in most of the market. Nevertheless the policy objective of improving quality at value for money prices was achieved for the near-monopoly provider within our case study area.     

Hybrid pricing in a coupled European power market with more wind power

In the European electricity market, the promotion of wind power leads to more network congestion. Zonal pricing (market coupling), which does not take the physical characteristics of transmission into account, is the most commonly used method to relieve network congestion in Europe. However, zonal pricing fails to provide adequate locational price signals regarding scarcity of energy and thus creates a large amount of unscheduled cross-border flows originating from wind-generated power. In this paper, we investigate the effects of applying a hybrid congestion management model, i.e., a nodal pricing model for one country embedded in a zonal pricing system for the rest of the market. We find that, compared to full nodal pricing, hybrid pricing fails to fully utilize all the resources in the network and some wrong price signals might be given. However, hybrid pricing still outperforms zonal pricing. The results from the study cases show that, within the area applying nodal pricing, better price signals are given; the need for re-dispatching is reduced; more congestion rent is collected domestically and the unit cost of power is reduced.