Service outsourcing under co-opetition and information asymmetry

Co-opetition refers to the phenomenon that firms simultaneously cooperate and compete in order to maximize their profits. This paper studies the contracting for an outsourcing supply chain (a user company vs. a service provider) in the presence of co-opetition and information asymmetry. The user company outsources part of his service capacity at a discount price to the service provider for sale. The service provider charges a commission for doing outsourcing work and competes with the user company for the service capacity to satisfy their respective demands. We solve for the service provider’s optimal commission decision and the user company’s optimal outsourcing decisions (outsourcing volume and price discount) when the user company has private information about his service capacity. Specifically, we highlight the following observations. For the service provider, a menu of two-part tariffs that consist of a fixed commission and a per-volume commission can reveal the true type of the user company’s capacity; the user company’s optimal outsourcing proportion is quasi-convex and the optimal price discount is non-decreasing in his capacity volume, which is counterintuitive.     

Service capacity procurement of logistics service supply chain with demand updating and loss-averse preference

This paper studies the impacts of loss-averse preference on the service capacity procurement decisions with demand updating in a logistics service supply chain, which consists of one logistics service integrator and one functional logistics service provider. It starts from a basic two-stage Stackelberg game model, then, extends to three scenarios where either the integrator or the provider or neither of them has loss-averse preference. The impact of loss-averse preference on the decisions of supply chain members is discussed by comparing the four models. Our results reveal, first, the loss-averse preferences do not always affect the decisions of supply chain members. If certain conditions are satisfied, the logistics service integrator can benefit from its loss-averse preference. Second, the increased service level can affect the logistics service integrator's procurement strategy and the functional logistics service provider's pricing strategy. This effect is only related to the loss-averse preference of the functional logistics service provider. Last, under certain conditions, the total service capacity decreases with the increased service level, regardless of whether or not the supply chain members have loss-averse preferences.     

Dynamic Network-Based Discriminatory Pricing

We study the dynamic pricing decisions for competitive network service providers. We assume that each competing firm follows a three-part pricing scheme, which consists of an ongoing membership fee, a usage fee for communications within the networks, and another usage fee for communications across the networks. The difference between the two usage fees is the network-based price discount that allows price discrimination. We study the firms problems as a differential game and establish the optimal pricing policy as a Nash equilibrium feedback strategy depending on only the network sizes (i.e., the number of subscribers). We compare the dynamic network-based discount with the static discount. In the special case of a uniform calling pattern, we find that the firm network-based dynamic discount is always lower than the static discount; we find also that the firm that has a larger network can offer a bigger discount. These results are useful particularly for managers. To get further insights into the dynamic pricing policies, we explore the case of symmetric competition using numerical simulation.Communicated by G. Leitmann     

Posted price profit maximization for multicast by approximating fixed points

We describe an iterative fixed point approach for the following stochastic optimization problem: given a multicast tree and probability distributions of user utilities, find an optimal posted price mechanism—i.e., compute prices to offer the users in order to maximize the expected profit of the service provider. We show that any optimum pricing is a fixed point of an efficiently computable function. We can then apply the non-linear Jacobi and Gauss–Seidel methods of coordinate descent. We provide proof of convergence to the optimum prices for special cases of utility distributions and tree edge costs.     

双模式交通网络中的ATIS信息定价研究

先进的出行者信息系统(ATIS)是一种服务商品,已有的研究多从提高市场占有率的角度对单模式交通网络中的ATIS进行信息定价。多模式交通网络中影响ATIS市场占有率的因素众多,而且ATIS的提供成本往往与信息质量和使用规模同时相关。因此,信息定价问题应从ATIS服务提供商利润最大化的角度进行研究。本文把ATIS信息的单次使用费用和ATIS的信息质量同时作为决策变量,将双模式路网中ATIS的定价问题描述为一个双层规划模型。其中,混合用户均衡模型为下层模型,收益模型为上层模型。然后,基于上海市虹口区的路网数据,对下层模型进行了数值分析,并讨论了相关经济效益问题。此外,本文提出了求解下层模型的MSAF算法,并进一步嵌套了粒子群(PSO)算法,最终得到ATIS服务提供商的最优ATIS信息定价和信息质量提供方案。     

A stochastic fluid model for an ad hoc mobile network

In conventional mobile telephone networks, users communicate directly with a base station, via which their call is transferred to the recipient. In an ad hoc mobile network, there is no base-station infrastructure and users need to communicate between themselves, either directly if they are close enough, or via transit nodes if they are not. A number of interesting questions immediately arise in the modeling of ad hoc mobile networks. One that has received attention in the literature concerns how to encourage users to act as transit nodes for calls that they are not partaking in. Solutions to this problem have involved each user maintaining a ‘credit balance’ which is increased by forwarding transit calls and decreased by transmitting one’s own calls. A second question concerns the ‘amount of resource’ that a network needs in order to be able to operate with a reasonable quality of service. We shall consider this question by modeling each user’s battery energy and credit balance as fluids, the rate of increase or decrease of which is modulated by the network occupancy. This results in a network of stochastic fluid models, each modulated by the same background process. In this paper, we shall assume that there is no bound on the energy or the credit that a user’s handset can accumulate. Using this model, we can calculate the critical rates of recharge that are necessary and sufficient to guarantee that no calls are lost. For recharge rates less than the critical values, we propose a reduced-load approach to the analysis of the network.     

考虑云安全风险的个人云存储服务最优定价策略

针对现有个人云存储服务纷纷关闭的现象,如何根据不同市场时期和云用户特征,制定合理的定价策略已成为个人云存储服务商面临的挑战性问题。本文在考虑云安全风险,云用户感知价值及弹性成本对个人云存储服务定价的影响,建立了基于云安全风险的两阶段定价模型,给出了免费试用时长确定下的最优决策及免费试用时长不确定下的最优免费试用时长及最优价格。借助数值分析,进一步研究了云安全风险系数,云用户感知价值,云安全运营成本系数对最优免费时长,最优利润的影响,结果表明,当云安全风险系数适中时,个人云存储供应商(PCSP)采取两阶段定价策略。另外,最优利润随着云安全风险系数,免费试用时长,单位安全运营成本的增加先增加后减少。     

New formulations and solution procedures for the hop constrained network design problem

Optical fiber provides tremendous advantages in being able to carry a wide range of services including video on demand, video conferencing, distance learning, remote medical imaging, and telecommuting. The high capacities encourage carriers to create networks that are substantially sparser than previous copper based networks. A recent publication by the Telecommunications Industry Association indicated that investment in fiber optics is projected to reach $35 billion in the year 2003. Given the magnitude of investments, the design of networks becomes a very important issue. Most telecommunication companies (telcos), IT consulting companies, network equipment manufacturers and network service providers have extensive network design groups. The primary function of these groups is to design the most efficient networks both in terms of costs and performance and maintain them. These designers need flexible tools to support topological network design decisions. These decisions involve significant levels of investments in transmissions and switching facilities, and impact the resulting networks’ performance fundamentally.In this paper we study a special type of a network design problem called the hop constrained backbone network design problem. We present new mathematical programming formulations of the problem and develop an efficient solution procedure based on the linear programming relaxation. Extensive computational results across a number of networks are reported.     

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。     

Telecommunication Network Capacity Design for Uncertain Demand

The expansion of telecommunication services has increased the number of users sharing network resources. When a given service is highly demanded, some demands may be unmet due to the limited capacity of the network links. Moreover, for such demands, telecommunication operators should pay penalty costs. To avoid rejecting demands, we can install more capacities in the existing network. In this paper we report experiments on the network capacity design for uncertain demand in telecommunication networks with integer link capacities. We use Poisson demands with bandwidths given by normal or log-normal distribution functions. The expectation function is evaluated using a predetermined set of realizations of the random parameter. We model this problem as a two-stage mixed integer program, which is solved using a stochastic subgradient procedure, the Barahona's volume approach and the Benders decomposition.     

考虑路网可靠性和空间公平性的次优拥挤收费模型

根据随机路网环境下出行者规避风险的路径选择行为,提出了一种考虑路网可靠性和空间公平性的次优拥挤收费双层规划模型。其中,上层模型以具有空间公平性约束条件下最大化路网的社会福利为目标,下层模型是实施拥挤收费条件下考虑行程时间可靠性的弹性需求用户平衡模型。鉴于双层规划模型的复杂性,设计了基于遗传算法和FrankWolfe算法的组合式算法来求解提出的模型。算例结果表明:考虑行程时间可靠性的次优拥挤收费会产生不同于传统次优拥挤收费的平衡流量分布模式,表明出行者的路径选择行为对拥挤收费结果会产生直接影响;此外,算例结果还说明遗传算法对参数设置具有很强的鲁棒性。     

基于游客年龄特征的旅游巴士定价研究

为旅游巴士设计合理的定价,对旅游公共交通的发展有着积极影响。通过对游客出行偏好的分析,考虑不同年龄阶段的游客在选择行为上有较大的差异,建立了上层以旅游巴士企业利润最大为目标,下层为多方式多人群弹性需求随机用户平衡的旅游巴士定价模型,并设计了改进粒子群算法求解问题。数值实验结果表明:1)年龄特征会影响最优定价策略,考虑游客年龄在选择行为上的差异得出的票价更优;2)舒适度敏感系数对定价有影响,且旅游巴士较常规公交,舒适度更好,一定程度上提高了旅游巴士企业的竞争力;3)改进粒子群算法较标准粒子群算法,有更好的求解性能和质量。     

多方式弹性需求下公交定价双层规划模型

为描述多方式城市交通网络下公交定价与出行选择行为的相互作用与影响,将出行方式选择与路径选择涵盖于同一网络,建立了上层模型分别以企业利润最大化、乘客出行成本最小化和社会福利最大化为目标函数,下层模型为多方式弹性需求随机用户配流模型的公交定价双层规划模型。运用改进遗传算法对模型整体进行求解,下层模型采用综合对角化算法和MSA算法的组合求解算法。最后,设计了一个算例以说明模型应用。结果表明:运用双层规划模型所确定的公交票价较传统静态票价可使政府、企业及出行者三方都获得更高收益,且上层模型以社会福利最大化为目标函数能代表社会群体中多数人利益,优化效果最为理想。     

Optimizing revenue in CDMA networks under demand uncertainty

Mathematical programming models for telecommunications network design are prevalent in the literature, but little research has been reported on stochastic models for cellular networks. We present a stochastic revenue optimization model for CDMA networks inspired by bid pricing models from the airline industry. We describe the optimality conditions for the model and develop a supergradient algorithm to solve it. We provide computational results that show the effects of the distribution and variance of demand. Finally, we discuss areas of future research, including a method to optimize the locations of the towers.     

Pricing of full-service repair contracts

Full-service repair contracts are becoming increasingly popular, especially as an add-on to leasing contracts for technical investment products. This paper presents a model for pricing full-service repair contracts in the presence of risk-averse customers. The model identifies the optimal portfolio of full-service contracts and on-call service agreements to be offered by the service provider. The optimal full-service price is established, with failure arrivals being modeled as Poisson events and the cost of individual failures being stochastic. An existing on-call service business represents the price benchmark. The model is readily applicable for any service provider for small investment products such as special-purpose trucks or printing equipment.     

Multi-period traffic routing in satellite networks

We introduce a traffic routing problem over an extended planning horizon that appears in geosynchronous satellite networks. Unlike terrestrial (e.g., fiber optic) networks, routing on a satellite network is not transparent to the customers. As a result, a route change is associated with significant monetary penalties that are usually in the form of discounts (up to 40%) offered by the satellite provider to the customer that is affected. The notion of these rerouting penalties requires the network planners to explicitly consider these penalties in their routing decisions over multiple time periods and introduces novel challenges that have not been considered previously in the literature. We develop a branch-and-price-and-cut procedure to solve this problem and describe an algorithm for the associated pricing problem. Our computational work demonstrates that the use of a multi-period optimization procedure as opposed to a myopic period-by-period approach can result in cost reductions up to 13% depending on problem characteristics and network size considered. These cost reductions correspond to potential savings of several hundred million dollars for large satellite providers.     

抢占型优先服务机制下多类排队网络的扩散逼近

证明一个满负荷交通极限定理以证实在抢占型优先服务机制下多类排队网络的扩散逼近,进而为该系统提供有效的随机动力学模型．所研究的排队网络典型地出现在现代通讯系统中高速集成服务分组数据网络,其中包含分组数据包的若干交通类型,每个类型涉及若干工作处理类（步骤）,并且属于同一交通类型的工作在可能接受服务的每一个网站被赋予相同的优先权等级,更进一步地,在整个网络中,属于不同交通类型的分组数据包之间无交互路由．     

考虑质量偏好的两阶段服务供应链质量控制策略

研究了一个集成商和一个提供商所组成的服务供应链的质量控制问题。考虑集成商的质量缺陷承诺和提供商的质量偏好,并将提供商的质量活动区分为质量改进和质量保持两个阶段,分别建立了服务供应链成员的效用函数,同时考虑服务供应链成员的竞争与合作,运用博弈理论,优化得到单阶段与两阶段时,集成商的最优服务价格和质量缺陷承诺,以及提供商的最优服务质量改进程度。最后,通过对比分析及数值仿真发现,考虑两阶段质量控制较单阶段情形,更有利于服务供应链较长期限内获得更多效用。其次,服务提供商质量偏好对服务供应链单阶段与两阶段下的最优效用和质量控制策略均产生一定影响。