Modeling Precheck Parallel Screening Process in the Face of Strategic Applicants with Incomplete Information and Screening Errors

In security check systems, tighter screening processes increase the security level, but also cause more congestion, which could cause longer wait times. Having to deal with more congestion in lines could also cause issues for the screeners. The Transportation Security Administration (TSA) Precheck Program was introduced to create fast lanes in airports with the goal of expediting passengers who the TSA does not deem to be threats. In this lane, the TSA allows passengers to enjoy fewer restrictions in order to speed up the screening time. Motivated by the TSA Precheck Program, we study parallel queueing imperfect screening systems, where the potential normal and adversary participants/applicants decide whether to apply to the Precheck Program or not. The approved participants would be assigned to a faster screening channel based on a screening policy determined by an approver, who balances the concerns of safety of the passengers and congestion of the lines. There exist three types of optimal normal applicant's application strategy, which depend on whether the marginal payoff is negative or positive, or whether the marginal benefit equals the marginal cost. An adversary applicant would not apply when the screening policy is sufficiently large or the number of utilized benefits is sufficiently small. The basic model is extended by considering (1) applicants' parameters to follow different distributions and (2) applicants to have risk levels, where the approver determines the threshold value needed to qualify for Precheck. This article integrates game theory and queueing theory to study the optimal screening policy and provides some insights to imperfect parallel queueing screening systems.     

公司内部监督机制理论、模式及选择

有限责任、独立人格和分权制衡是现代公司制度的三大基石.大多数国家公司内部监督机制是在分权制衡的基石上建构起来的,也有些国家的公司内部监督机制还受内部规制理论的影响,因而表现出不同的特色.但无论采取何种模式,应该说都是公司制度发展的内在需要和必然.     

双重关系——社会工作中专业关系的伦理困境

伦理是社会工作中的重要议题。在实务领域中,当社会工作者与案主不单是两者之间的专业关系,而产生了朋友、雇主、师生、商业伙伴甚至性伙伴等关系的时候,他就陷入了双重关系的困境。文章从美国社会工作伦理守则历次修订对此的限制入手,完整介绍双重关系的定义与分类,并提出处理双重关系的办法与建议。     

基于电子市场的供应链双渠道冲突与协调的契约设计

研究了一个制造商通过传统零售渠道销售产品的同时开辟网上直销渠道,采取混合双渠道来销售产品的供应链渠道结构。从分析消费者效用出发,建立了双渠道环境下需求依赖价格变化的需求函数,运用博弈论建立决策模型。结果表明制造商在保持传统渠道的同时,开辟电子渠道将导致传统零售商的市场份额减少,利润降低,引起渠道冲突。为了解决混合双渠道的冲突和协调,设计了批发价加电子渠道价格的合同实现了双渠道供应链的协调,通过改进的收入共享契约不但实现了双渠道供应链的协调,而且实现了开辟电子渠道后供应链各成员利润的帕累托改进,从而实现了供应链双渠道冲突的协调问题。     

Analysis of the List Scheduling Algorithm for Precedence Constrained Parallel Tasks

Given P processors, and a set of precedence constrained parallel tasks with their processor requirements and execution times, the problem of scheduling precedence constrained parallel tasks on multiprocessors is to find a nonpreemptive schedule of the tasks on a multiprocessor with P processors, such that the schedule length is minimized. We show that for many heuristic choices of the initial priority list, the list scheduling algorithm has worst-case performance ratio P, which is unbounded as P gets large. However, it is also shown that when task sizes are bounded from above by a fraction of P, the list scheduling algorithm has finite worst-case performance ratio. In particular, we prove that if all tasks request for no more than qP processors, where 0 < q < 1, then the worst-case performance ratio of the list scheduling algorithm is no larger than

Dual Sourcing Under Random Supply Capacities: The Role of the Slow Supplier

Sourcing from multiple suppliers with different characteristics is common in practice for various reasons. This paper studies a dynamic procurement planning problem in which the firm can replenish inventory from a fast and a slow supplier, both with uncertain capacities. The optimal policy is characterized by two reorder points, one for each supplier. Whenever the pre‐order inventory level is below the reorder point, a replenishment order is issued to the corresponding supplier. Interestingly, the reorder point for the slow supplier can be higher than that of the fast even if the former has a higher cost, lower reliability, and smaller capacity than the latter, suggesting the possibility of ordering exclusively from an inferior slow supplier in the short term. Moreover, the firm may allocate a larger portion of the long‐term total order quantity to the slow supplier than to the fast, even if the former does not possess any cost or reliability advantage over the latter. Such phenomena, different from the observations made in previous studies, happen when the demand is uncertain and the supply is limited or unreliable. Our observations highlight the importance of incorporating both demand uncertainty and supplier characteristics (i.e., cost, lead time, capacity and uncertainty) in a unified framework when formulating supplier selection and order allocation strategies.     

基于顾客渠道偏好的服务竞争模型

由传统零售渠道和在线直销渠道组成的双渠道供应链中,两种渠道带给顾客不同的购物服务体验,能更好地满足不同渠道偏好的顾客需要,但两种渠道之间又存在竞争关系。针对两种渠道带给顾客的服务体验的差异性,构建考虑顾客渠道偏好的双渠道供应链服务竞争模型,研究制造商的最优渠道选择策略以及在线渠道的增加给传统单渠道供应链和顾客带来的影响。研究结果表明,能否扩大市场需求是判断制造商是否选择双渠道策略的充分条件,但是增加在线渠道之后,供应链存在服务歧视现象,可能造成市场需求减少;在线渠道的增加始终损害零售商的利益,并且可能导致供应链整体收益减少和顾客整体效用水平下降,最终导致社会福利的损失。借助数值分析发现,如果存在大量未开拓的潜在市场需求,顾客对在线渠道偏好程度的提高将有助于提升供应链整体收益和顾客整体效用水平,反之亦然。     

并联决策单元的动态DEA效率评价研究

具有并联决策单元内部结构的系统是一类具有代表性的复杂生产系统,其内部结构已不再是传统观念的黑箱,而是由多个并联(平行)的生产单位组成.在已有并联决策单元DEA效率评价方法的基础上加入时间维度,增加规划问题的约束条件,推演出该种复杂系统的动态DEA效率评价指标,并以中国14家商业银行的数据进行实证.研究结果表明,2005年至2008年没有一家银行的动态效率指数为0,这说明中国银行系统的生产效率并没有达到最优;中国商业银行的地区效率基本遵循沿海地区-中部地区-西部地区依次递减的态势,此规律在中国国有银行中的体现更为明显;影响银行效率改进的主要原因是各银行本身的差异,而不是不同经济区域之间的环境差别.     

和谐管理理论指导下的合法性与独特性动态平衡机制研究

针对组织制定发展战略时不可避免的合法性与独特性权衡问题,基于和谐管理理论,选取案例研究的方法,探究组织如何实现最低合法性基础上的最优独特性。研究表明:“系统性整体设计、和谐主题制定与调整、围绕和谐主题的谐则-和则体系优化及动态耦合”可作为组织实现最低合法性基础上的最优独特性的指导性研究框架。此外,阐述了西交利物浦大学处理“求同还是存异”问题的办学实践与该研究框架的融合,于整体化的视角提出了独特性与合法性的权衡过程是一个有限干预下复杂系统的设计和演化问题。     

碳税政策下随机双渠道库存与协调研究

构建碳税政策下由单个制造商和单个零售商组成的双渠道供应链模型,在考虑渠道之间缺货转换的基础上,研究批发价格合约和双向收入共享契约下渠道间双渠道库存竞争问题,并设计了由双向收入共享合约和转移支付机制组成的组合合约机制使制造商和零售商实现共赢,以此保证合约的有效执行。研究表明：批发价合约和双向收入共享合约下,制造商分别通过调控批发价格和收入分享比例来调控双渠道的库存水平,其中网络渠道最优库存水平随着零售渠道单位碳排放量增加而增加,零售商的库存水平随着其单位碳排放量增加而减少。进一步分析了渠道间单位产品碳排放差异对批发价格,以及传统零售渠道和网络渠道库存水平的影响如何受到缺货转换率和碳税税率的调节。