Revenue maximization in two-station tandem queueing systems

We study optimal pricing for tandem queueing systems with finite buffers. The service provider dynamically quotes prices to incoming price sensitive customers to maximize the long-run average revenue. We present a Markov decision process model for the optimization problem. For systems with two stations, general-sized buffers, and two or more prices, we describe the structure of the optimal dynamic pricing policy and develop tailored policy iteration algorithms to find an optimal pricing policy. For systems with two stations but no intermediate buffer, we characterize conditions under which quoting either a high or a low price to all customers is optimal and provide an easy-to-implement algorithm to solve the problem. Numerical experiments are conducted to compare the developed algorithms with the regular policy iteration algorithm. The work also discusses possible extensions of the obtained results to both three-station systems and two-station systems with price and congestion sensitive customers using numerical analysis.     

Prospect theory and foreign policy decision-making: Underexposed issues,advancements, and ways forward

How much mileage can we get out of prospect theory to explain foreign policy decision-making? To answer this question, we first argue that risk as outcome uncertainty is the appropriate definition in prospect-theoretical applications. Then, we indicate that probability weighting—a crucial component of prospect theory—is typically ignored in such applications. We argue why this is problematic and suggest how to move forward. Next, we discuss how to establish the reference point in the face of outcomes in multiple dimensions, as is typically the case in foreign policy decision-making. Finally, we discuss what we have learnt regarding prospect theory’s scope conditions and the differences across individuals in the theory’s applicability. Overall, our contribution lies in identifying several underexposed or neglected issues (e.g., the definition of risk and probability weighting), in examining the advancements regarding prospect theory’s scope conditions, and in discussing avenues for further research.     

Is human trafficking the dark side of economic freedom?

Economic freedom has increased living standards worldwide. Concurrent with such gains are rising concerns about potential human costs associated with free markets. This paper uses data on human trafficking and anti-trafficking policies, in conjunction with a measure of economic freedom, to examine whether free markets exacerbate or attenuate the incidence of human trafficking and policies designed to combat it. We do not find evidence suggesting that economic freedom is associated with human trafficking. In addition, our results suggest that economically free countries are more likely to enact and enforce policies to fight human trafficking.     

无人机滑跑航迹控制模型与控制精度分析

航迹偏差的控制精度对滑跑起降至关重要,地面滑跑纠偏建模和地空航迹控制的切换策略是起降航迹控制设计的难点。从运动学关系出发,提出了地面滑跑纠偏控制的设计模型,使得复杂的地面航偏控制规律易于设计;利用同-反馈结构在多个状态的协调控制,实现了地空状态自然过渡的航迹控制切换策略;最后提出了提高航迹控制精度和进行风干扰补偿的措施。     

A bivariate optimal replacement policy for a cold standby repairable system with repair priority

In this article, an optimal replacement policy for a cold standby repairable system consisting of two dissimilar components with repair priority is studied. Assume that both Components 1 and 2, after repair, are not as good as new, and the main component (Component 1) has repair priority. Both the sequence of working times and that of the components'repair times are generated by geometric processes. We consider a bivariate replacement policy (T,N) in which the system is replaced when either cumulative working time of Component 1 reaches T, or the number of failures of Component 1 reaches N, whichever occurs first. The problem is to determine the optimal replacement policy (T,N)* such that the long run average loss per unit time (or simply the average loss rate) of the system is minimized. An explicit expression of this rate is derived, and then optimal policy (T,N)* can be numerically determined through a two‐dimensional‐search procedure. A numerical example is given to illustrate the model's applicability and procedure, and to illustrate some properties of the optimal solution. We also show that if replacements are made solely on the basis of the number of failures N, or solely on the basis of the cumulative working time T, the former class of policies performs better than the latter, albeit only under some mild conditions. © 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010     

Rolling‐horizon replenishment: Policies and performance analysis

We consider a rolling‐horizon (RH) replenishment modeling framework under which a buyer can update demand information and inventory status, modify order quantities committed previously, place an advanced order for a new period at the end of the RH, and move along in time seamlessly. We show that the optimal order policy for the two‐period RH problem is a dual‐threshold type for updating period(s) plus a base‐stock type for the advanced order. We provide analytical formulas and algorithms to compute the optimal thresholds and the optimal base‐stock level exactly. With our analytical results and numerical procedures, we demonstrate the significant value of RH replenishment in matching supplies to demands more closely. We also show that with RH updating (flexibility), the value of additional demand information beyond the RH diminishes quickly. © 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010     

宽严相济刑事政策及其所折射出的中国刑事政策走向

宽严相济刑事政策是我国当前控制犯罪的基本刑事政策。在宽严相济政策的基础上,我国刑事政策将会进一步体现中国传统文化,更好地尊重与保护公民的基本人权,进一步影响刑事立法、司法活动,进一步体现刑事司法活动的预防、教育功能。     

谈奥巴马时代美国的联合国政策

奥巴马对联合国政策的调整,反映出奥巴马政府全球外交和安全战略的需要,体现了实用主义外交风格。较之于其前任,奥巴马将更加重视联合国维和行动,并让联合国更多地参与解决包括伊拉克和阿富汗在内的热点问题。奥巴马的联合国政策面临挑战,联合国仅仅是奥巴马实现美国国家利益的手段之一。     

Technical note: Reexamination of all‐or‐none inspection policies in a supply chain with endogenous product quality

This note studies the optimal inspection policies in a supply chain in which a manufacturer purchases components from a supplier but has no direct control of component quality. The manufacturer uses an inspection policy and a damage cost sharing contract to encourage the supplier to improve the component quality. We find that all‐or‐none inspection policies are optimal for the manufacturer if the supplier's share of the damage cost is larger than a threshold; otherwise, the manufacturer should inspect a fraction of a batch. © 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008     

An optimal critical level policy for inventory systems with two demand classes

Traditional inventory systems treat all demands of a given item equally. This approach is optimal if the penalty costs of all customers are the same, but it is not optimal if the penalty costs are different for different customer classes. Then, demands of customers with high penalty costs must be filled before demands of customers with low penalty costs. A commonly used inventory policy for dealing with demands with different penalty costs is the critical level inventory policy. Under this policy demands with low penalty costs are filled as long as inventory is above a certain critical level. If the inventory reaches the critical level, only demands with high penalty costs are filled and demands with low penalty costs are backordered. In this article, we consider a critical level policy for a periodic review inventory system with two demand classes. Because traditional approaches cannot be used to find the optimal parameters of the policy, we use a multidimensional Markov chain to model the inventory system. We use a sample path approach to prove several properties of this inventory system. Although the cost function is not convex, we can build on these properties to develop an optimization approach that finds the optimal solution. We also present some numerical results. © 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008