考虑道德风险与货损追溯的物流货损控制合约设计

考虑物流货损受包装合理化和运输合理化的双重影响,研究了货主企业面向运输企业的最优合约设计问题。在单边道德风险环境下,运输企业的运输合理化努力不可见;在双边道德风险环境下,运输企业的运输合理化努力和货主企业的包装合理化努力均不可见。基于委托-代理理论,针对货主企业货损追溯能力是否可控分别设计了两种风险环境下的激励与惩罚合约。研究发现,要使物流货损率降到最低,在单边道德风险环境下,单一的激励合约或单一的惩罚合约都能够起作用,但是在双边道德风险环境下,激励合约和惩罚合约必须联合使用;双边道德风险环境下的最优合约也适用于单边道德风险环境;此外,货主企业的货损追溯能力越强,面向运输企业的惩罚力度应当越小;与货损追溯能力外生时相比,货损追溯能力为内生时的惩罚力度应当更小。     

基于条件风险值理论的供应链优化与协调模型研究

本文将近年来发展起来的金融风险控制工具--条件风险值,引入具有风险规避特性的供应链优化与协调问题的研究.建立了随机需求下由具有不同风险规避特性的单个供应商与单个零售商组成的两级供应链的条件风险值模型和基于条件风险值的最优订购量模型及协调供应链的收入共享契约模型,并对模型进行了分析,揭示了供应商和零售商的风险规避程度对最优订购量、批发价格及供应链协调的影响.最后通过一个算例对模型进行了仿真,仿真结果进一步验证了本文的研究结论.     

Quantity Flexibility Contracts: Optimal Decisions with Information Updates*

We study single and multiperiod quantity flexibility contracts involving one demand forecast update in each period and a spot market. We obtain the optimal order quantity at the beginning of a period and order quantities on contract and from the spot market at the then prevailing price after the forecast revision and before the demand materialization. The amount that can be purchased on contract is bounded by a given flexibility limit. We discuss the impact of the forecast quality and the level of flexibility on the optimal decisions and managerial insights behind the results.     

差价合约下电网公司购电费用最小化的离散优化模型

以购电费用最小化为目标函数,构建了差价合约下电网公司在合约市场、现货市场、备用市场和可中断负荷交易市场上的最优购电模型,并利用启发式算法给出了该模型的求解算法,最后,通过算例分析了差价合约及合约电量比重对电网公司购电费用的影响。     

航空客运舱位控制和超售综合静态建模研究

本文研究航空运输收益管理的舱位控制和超售综合静态建模问题.通过将机票销售过程模拟成排队过程,以收益最大化为目标函数,首先给出了单航段单等级票价下的超售水平公式.然后将该思路推广到多等级票价情况,应用动态规划方法建立了舱位控制和超售综合控制静态模型,在建立了两个定理的基础上,由该模型进一步推导出了各等级舱位最优订座限制的决策方程.最后分析了一个实例以说明决策方程的应用.     

Clinic Overbooking to Improve Patient Access and Increase Provider Productivity*

The problem of patient no‐shows (patients who do not arrive for scheduled appointments) is significant in many health care settings, where no‐show rates can vary widely. No‐shows reduce provider productivity and clinic efficiency, increase health care costs, and limit the ability of a clinic to serve its client population by reducing its effective capacity. In this article, we examine the problem of no‐shows and propose appointment overbooking as one means of reducing the negative impact of no‐shows. We find that patient access and provider productivity are significantly improved with overbooking, but that overbooking causes increases in both patient wait times and provider overtime. We develop a new clinic utility function to capture the trade‐offs between these benefits and costs, and we show that the relative values that a clinic assigns to serving additional patients, minimizing patient waiting times, and minimizing clinic overtime will determine whether overbooking is warranted. From the results of a series of simulation experiments, we determine that overbooking provides greater utility when clinics serve larger numbers of patients, no‐show rates are higher, and service variability is lower. Even with highly variable service times, many clinics will achieve positive net results with overbooking. Our analysis provides valuable guidance to clinic administrators about the use of appointment overbooking to improve patient access, provider productivity, and overall clinic performance.     

突发性产出下的供应链协调应对策略

针对突发事件影响制造商产出的情形，研究了收益共享契约协调应对突发产出事件的有效性问题。首先论证了无突发产出事件时收益共享契约协调供应链的有效性，进而分析了突发产出事件对供应链最优生产计划、定价决策、绩效和协调性的影响。然后，建立了突发产出事件下的收益共享契约协调应对模型，并对原收益共享契约和修正后的收益共享契约进行了对比分析。研究表明：当突发产出事件导致产出扰动范围较小时，供应链的最优生产计划、批发价格和零售价格几乎保持不变，仅当产出扰动范围较大时，三者才需要同时调整，此时原供应链的协调性也将被打破，而修正后的收益共享契约具有良好的抗突发性。最后，通过算例进行了验证。     

基于SaaS模式的服务供应链协调研究

免费试用是SaaS(软件即服务)模式市场推广的主要方式,本文研究了服务需求由服务的免费试用决定的SaaS服务供应链中AIP(应用基础设施提供商)与ASP(应用服务提供商)间的协调问题。在信息对称下,以成本共担契约激励ASP提高免费试用的努力水平;在信息不对称的情况下,AIP采用服务能力预定策略避免低技术能力ASP的机会主义行为,通过成本与风险共担的组合契约激励ASP提高免费试用的努力水平和提高服务能力订购量。研究结果表明:提出的协调契约能够使免费试用的效果达到整体最优,实现SaaS服务供应链的最优绩效并使各参与方利润帕累托改进;提高ASP的技术能力可使免费试用取得更好的效果。通过数值模拟验证了模型的有效性并得出了其管理学意义。     

基于收益共享-双向期权契约的供应链金融风险控制研究

通过核心企业的信用水平为中小企业获取贷款提供担保,使得整个供应链有效运行是实施供应链金融的重要意义。本文考虑分销商（核心企业）-零售商（贷款企业）组成的二级供应链,为了降低银行面临的零售商违约风险,在银行监督下,分销商与零售商引入收益共享—双向期权契约。本文计算得到了零售商的违约概率,在此基础上,深入分析了各方期望收益、零售商最优初始订货量与最优期权购买数量、分销商最优收益共享比例、银行下侧风险规避前提下可参考的收益共享比例范围。并构造了数值算例,探讨了期权执行价格、收益共享比例及银行质押率等关键参数对风险控制方面的影响。本文所得结果能够为银行及企业在供应链金融决策方面提供参考。     

考虑风险规避的资金约束供应链最优信用契约设计

本文针对零售商的资金约束问题,研究了风险规避的供应商如何通过设计信用契约影响零售商的融资结构。构建了包含供应商、零售商以及银行在内的供应链融资模型,给出了供应商的最优信用契约决策、零售商的最优库存决策以及银行的最优利率决策。进一步分析了供应商的风险规避程度对最优信用契约决策的影响。研究表明：当供应商的风险规避程度低于某个临界值时,供应商偏好提供全额信用,从而零售商的融资结构为单一的交易信用融资;而当供应商的风险规避程度高于该临界值时,供应商偏好提供部分信用,从而零售商的融资结构为组合融资。最后,通过数值算例验证了本文的结论。本研究一定程度上丰富了现有供应链金融的理论研究,为供应链核心企业与银行的决策提供了依据与参考。     

Managing appointments with waiting time targets and random walk-ins

The random arrivals of walk-in patients significantly affect the daily operations of healthcare facilities. To improve the performance of outpatient departments, this paper attempts to make an appointment schedule by considering walk-ins and the waiting time target (WTT) for appointment patients. A stochastic programming model is proposed to solve this problem with the objective of minimizing the weighted patient waiting and makespan cost. A non-decreasing waiting cost function is used to capture the WTT fulfillment of appointment patients, whereas walk-ins incur a linear waiting cost. A finite-horizon Markov Decision Process model is formulated to establish the optimal real-time scheduling policy under a given appointment schedule. The appointment schedule is determined by a two-stage stochastic programming approximation and a local search improvement. Structural properties of the optimal appointment scheduling and real-time scheduling policies are established. In particular, it is shown that appointment overbooking is allowed only at the end of the regular session, and the optimal real-time scheduling policy is an easy-to-implement threshold policy with bounded sensitivity. Numerical experiments based on real data are performed to investigate the influence of different parameters and to compare different schedules. The optimal schedule demonstrates superior performance by allowing reasonable waiting times for appointment patients depending on their WTTs. Managerial insights are also provided to hospital managers. Finally, the basic model is extended by incorporating random service times and random arrivals of appointment patients. The latter includes the random number of patients that show up for service or call for appointments, and the random arrival time (unpunctuality). Appointment overbooking strategies are shown to have different structures under some stochastic factors.     

面向关键设备维修服务的PBC合同与营业中断险集成设计模型及分析

高可用度运行是关键设备系统运营企业产生收益的根本保障。为了减小因小概率突发故障造成的严重收益损失以及可能地继发资金流风险,既要设计合理的服务合同增强对服务供应商的激励,又要同时考虑收益损失减缓策略。基于性能合同（PBC）是根据服务结果给予补偿的新兴激励合同,而购买营业中断保险（BI）是减缓关键设备故障继发资金流风险的有效策略。本文以委托-代理理论为建模框架,研究BI保险与PBC合同集成设计模型,探讨购买保险与否两种情景下的PBC合同最优设计和供应商的最优服务能力决策,分析BI保险决策对PBC合同设计方案的影响规律,调查运营商购买BI保险的决策条件。该成果是维修服务运作与金融保险领域跨界研究的首次尝试,其理论分析结果有助于为关键设备运营企业跨部门决策提供指导。     

EPR制度意义下制造商和零售商激励契约研究

在EPR制度约束下,制造商和零售商之间形成产品供销和回收委托代理关系。本文通过引入废旧产品回收对产品销量的影响因子概念,建立了EPR制度约束下的制造商和零售商委托代理激励契约模型。通过该模型的分析,制造商可以设计最优激励契约,使自身的期望利润效用最大化;零售商通过一定的销售努力和回收努力投入(最优努力投入),可获得制造商提供的最优激励支付,从而实现期望利润效用的最大化。     

Appointment Scheduling with No‐Shows and Overbooking

We study an overbooking model for scheduling arrivals at a medical facility under no‐show behavior, with patients having different no‐show probabilities and different weights. The scheduler has to assign the patients to time slots in such a way that she minimizes the expected weighted sum of the patients' waiting times and the doctor's idle time and overtime. We first consider the static problem, where the set of patients to be scheduled and their characteristics are known in advance. We partially characterize the optimal schedule and introduce a new sequencing rule that schedules patients according to a single index that is a function of their characteristics. Then we apply our theoretical results and conclusions from numerical experiments to sequential scheduling procedures. We propose a heuristic solution to the sequential scheduling problem, where requests for appointments come in gradually over time and the scheduler has to assign each patient to one of the remaining slots that are available in the schedule for a given day. We find that the no‐show rate and patients' heterogeneity have a significant impact on the optimal schedule and should be taken under consideration.     

Adverse Selection in Competitive Search Equilibrium

We study economies with adverse selection, plus the frictions in competitive search theory. With competitive search, principals post terms of trade (contracts), then agents choose where to apply, and they match bilaterally. Search allows us to analyze the effects of private information on both the intensive and extensive margins (the terms and probability of trade). There always exists a separating equilibrium where each type applies to a different contract. The equilibrium is unique in terms of payoffs. It is not generally efficient. We provide an algorithm for constructing equilibrium. Three applications illustrate the usefulness of the approach, and contrast our results with those in standard contract and search theory.     

Panel Size and Overbooking Decisions for Appointment‐Based Services under Patient No‐Shows

Many service systems that work with appointments, particularly those in healthcare, suffer from high no‐show rates. While there are many reasons why patients become no‐shows, empirical studies found that the probability of a patient being a no‐show typically increases with the patient's appointment delay, i.e., the time between the call for the appointment and the appointment date. This paper investigates how demand and capacity control decisions should be made while taking this relationship into account. We use stylized single server queueing models to model the appointments scheduled for a provider, and consider two different problems. In the first problem, the service capacity is fixed and the decision variable is the panel size; in the second problem, both the panel size and the service capacity (i.e., overbooking level) are decision variables. The objective in both cases is to maximize some net reward function, which reduces to system throughput for the first problem. We give partial or complete characterizations for the optimal decisions, and use these characterizations to provide insights into how optimal decisions depend on patient's no‐show behavior in regards to their appointment delay. These insights especially provide guidance to service providers who are already engaged in or considering interventions such as sending reminders in order to decrease no‐show probabilities. We find that in addition to the magnitudes of patient show‐up probabilities, patients' sensitivity to incremental delays is an important determinant of how demand and capacity decisions should be adjusted in response to anticipated changes in patients' no‐show behavior.     

供应链中的批量与信用期联合决策研究

信用支付契约是使供应链各方达到协调的重要手段。本文在单个制造商和单个零售商组成的两级供应链系统下,建立了制造商和零售商的库存控制模型,提出了联合决策零售商的订货批量,以及制造商的生产批量和定期信用支付期的启发式算法。给出了利润分配方案,以使供应链达到协调。最后,本文通过算例验证了模型和算法的有效性,为运用信用支付契约协调供应链提供了理论依据。     

The Firm as a Means of Concealing Information

The aim of this paper is to demonstrate that a firm may owe its continued existence to its attempts to conceal information from its competitors about the unknown characteristics of a certain factor, not just to its savings on market transaction costs, its team‐working, risk‐sharing, or the encouragement of ex ante specific investment. This is because the existence of a firm contract severs the relationship between the factor market and the product market, thereby making it difficult for outsiders to observe the marginal contribution of the intermediate factor and make statistical inferences about the factor's unknown characteristics. Furthermore, an optimal contract is determined by a trade‐off not only between traditional risk‐sharing and incentive, but also between the incentive and information concealing. Finally, we show that this latter kind of trade‐off also affects the position of the optimal boundary of the firm.     

Simple Efficient Contracts in Complex Environments

This paper studies a general model of holdup in a setting encompassing the models of Segal (1999) and Che and Hausch (1999) among others. It is shown that if renegotiation is modeled as an infinite‐horizon noncooperative bargaining game, then, with a simple initial contract, an efficient equilibrium will generally exist. The contract is robust in the sense that it does not depend on fine details of the model. The contract gives authority to one party to set the terms of trade and gives the other party a nonexpiring option to trade at these terms. The difference from standard results arises because the initial contract ensures that the renegotiation game has multiple equilibria; the multiplicity of continuation equilibria can be used to enforce efficient investment.     

A DISCRETE DYNAMIC OPTIMIZATION MODEL FOR MADE-TO-ORDER COST ANALYSIS

A model is presented that yields optimal production rates for a firm producing a contracted order. The model is unique in that it considers the influence of production rate and learning on total program cost. An application to the specific characteristics of two military production programs is presented. As demonstrated by the application, models of this type may be used as decision-making tools when negotiating the cost impact of contract modifications.