Information revelation in sequential auctions with uncertainties about future objects

In many auctions, buyers know beforehand little about objects to be sold in the future. Whether and how to reveal information about future objects is an important decision problem for sellers. In this paper, two objects are sold sequentially and each buyer’s valuation for the second object is k times that for the first one, and the true value of k is sellers’ private information. The authors identify three factors which affect sellers’ revelation strategies: The market’s competition intensity which is characterized by the number of buyers, buyers’ prior information about the second object, and the difference degree between two objects which is characterized by k. The authors give not only conditions under which revealing information about the second object in advance benefits the seller, but also the optimal releasing amount of information in the market with two sellers and one seller, respectively.     

Analysis of G-Queue with Pseudo-Fault and Multiple Working Vacations

This paper presents a new model of discrete time Geo/Geo/1 repairable queueing system with pseudo-fault, negative customers and multiple working vacations. The authors assume that system service may be interrupted by breakdown or pseudo-fault, this system may become disabled only when it is in a regular busy period, and negative customers adopt two types of typical killing strategies. In this paper, the authors know that the evolution of the system can be described by a two-dimensional Markov chain, and the two-dimensional Markov chain satisfies the condition of quasi birth and death chains. Based on the method of matrix-geometric solution, the authors obtain distributions for the stationary queue length in RCH and RCE strategy, respectively. Moreover, the reliability of the system is analyzed and the number of customers and waiting time of a customer in the system in steady state are obtained. The authors analyze the impact of two killing strategies on the system comparatively.This paper studies the individually and socially optimal behaviors of positive customers, and presents a pricing policy for positive customers, therefore, the authors obtain the socially optimal arrival rate.Various numerical results are provided to show the change of performance measures.     

An Economic Model-Based Matching Approach Between Buyers and Sellers Through a Broker in an Open E-Marketplace

A broker in an open e-marketplace enables buyers and sellers to do business with each other. Although a broker plays an important role in e-marketplaces, theory and guidelines for matching between buyers and sellers in multi-attribute exchanges are limited. Therefore, a challenge for a broker’s responsibility is how to maximize a buyer’s total satisfaction degree as its goals under the consideration of trade-off between a buyer’s buying quantity and price paid to a seller, and other attributes. To solve this challenge, this paper proposes an economic model-based matching approach between a buyer’s requirements and a seller’s offers. The major contributions of this paper are that (i) a broker can model a seller’s price policy as per a buyer’s buying quantity through communication between a broker and a seller; (ii) due to each buyer’s different quantity demand, a broker models a buyer’s satisfaction degree as per a buyer’s buying quantity based on communication between a broker and a buyer; and (iii) to carry out a broker’s matching processes, an objective function and a set of constraints are generated to help a broker to maximize a buyer’s total satisfaction degree. Experimental results demonstrate the good performance of the proposed approach.     

基于M/M/1/SV排队的均衡门限策略

考虑单重休假M/M/1排队, 在部分可视的前提下, 研究顾客的均衡门限策略, 首次将单重休假机制引入到连续时间排队经济学模型中. 系统的决策主体是顾客, 突破了以往只注重服务机构单方面行为的局限. 基于“收入-支出”结构, 利用马尔可夫过程理论, 通过求解差分方程, 分析了系统的稳态行为, 得到了顾客的平均逗留时间; 进而构造适当的函数, 给出了寻找 均衡纯门限策略, 均衡混合门限策略的具体方法并证明之; 而后在不同的策略下, 得出了系统的稳态分布和均衡社会收益; 最后, 通过数值实验分析了均衡行为的各指标对系统参数的敏感性. 研究结果为顾客决策提供了优化建议, 同时为管理者研究系统中的定价问题提供了理论参考.     

Advance selling in the presence of product diffusion effect

Product diffusion refers to the phenomenon that the later demand is dependent on the early sales. To investigate how a firm’s advance selling strategy is affected by the effect of product diffusion, we consider a monopolist seller who sells a fashionable product in a market that comprises of myopic and strategic consumers over two periods (i.e., the advance selling season and the regular selling season). For a linear product diffusion effect we find that, when the effect of product diffusion is positive, the seller may set an extremely high advance selling price to induce the strategic consumers to purchase in the regular selling season, which is counter-intuitive. Moreover, the optimal procurement quantity for the seller may increase in the negative effect of product diffusion and decrease in the amount of strategic consumers. When we extend our model to consider a concave quadratic product diffusion effect, however, the optimal procurement quantity is concave in the amount of strategic consumers. Numerical studies are further presented to discuss the managerial insights.     

A RISK-AVERSE NEWSVENDOR MODEL WITH LIMITED CAPACITY AND OUTSOURCING UNDER THE CVAR CRITERION

For seasonal products,the retailers usually launch various marketing efforts,like advertising and promotion,to promote them in a selling season.While facing large demand from the customers,one should take the capacity constraint and outsourcing into consideration.Considering the shorten life cycles of most products,in this paper we adopt the traditional newsvendor model to investigate the optimal marketing effort along with optimal order quantity.We address the risk aversion issue and characterize the influence of the sellers’ risk propensity with CVaR criterion,and we develop an effective algorithm to obtain the optimal strategy.The impact of sellers’ risk propensity on the performance of the system is illustrated via numerical examples.The innovation of this paper is threefold.First,the optimal joint strategy of the marketing effort and order quantity is investigated and an efficient algorithm to find the optimal strategy is developed.Second,the capacity constraint option and an outsourcing strategy are studied jointly for excess products.Finally,the risk propensity of the seller and its influence are investigated by using the CVaR criterion,through which we obtain some new managerial insights.     

基于二层信用策略且存货影响销售率的库存模型

研究一类存货影响销售率的库存问题,其中采用二层信用支付策略,即供应商向零售商提供信用支付期,同时零售商也向顾客信用支付期;建立了相应的库存模型,证明了零售商最优订购策略是存在且唯一的,最后给出最优订货策略的算法与数值例子。     

Equilibrium Customer Strategies in Markovian Queues with Setup Times and Partial Failures

This paper considers the equilibrium behavior of customers in a Markovian queue with setup times and partial failures, where the reactivated server must go through a period of setup time to reach the normal working state and a failure can occur at any time during the normal service. When a partial failure occurs, the server continues to serve the customers on spot at a low rate and does not admit a new arrival. Once the system becomes empty, an exponential repair time starts. Assuming that all the customers have the option of joining or balking based on a linear reward-cost structure, the authors analyze the equilibrium strategies of the customers and the average social benefits of the system in the fully observable case and the partially observable case, respectively. And on this basis, the effect of several parameters on customers' strategic behavior is presented by some numerical examples.     

设备多状态、多类顾客制造系统的生产速率和库存分配联合决策

在生产制造系统中, 设备状态严重制约系统产能, 并增加生产过程的不确定性. 为应对不确定性对系统的影响, 对顾客进行细分, 实施差异化服务. 在顾客泊松达到、 缺货不补的假设下, 研究了设备多状态、多类顾客制造系统的生产和库存分配联合决策问题. 利用马尔科夫决策理论, 建立了系统在无限期期望折扣总成本准则和平均成本准则下的最优方程, 并证明了最优策略具有相似的结构性质. 最优生产速率策略是生产阈值水平随设备状态非增的阈值策略, 即当库存水平降至该阈值水平之下时, 以允许的最大生产速率生产, 否则不生产. 最优库存分配策略是分配阈值水平随设备状态非增的阈值策略. 另外, 缺货成本大的顾客具有较低的分配阈值.     

考虑佣金率的一口价拍卖模型

针对现实拍卖中卖方通常将拍品委托给拍卖行进行拍卖,建立了带佣金率和保留价的一口价拍卖模型.运用博弈理论,首先分析了投标者的均衡策略,然后在给定佣金率的前提下研究了卖方的最优保留价和最优一口价,接着在给定保留价和一口价的前提下研究了拍卖行的最优佣金率研究发现:与不考虑佣金率的情形不同,在考虑佣金率的模型中,一口价有正的概率被投标者选择,即卖方在拍卖中设置一口价可以提高其收益,且卖方的最优保留价大于不设置一口价的模型中的最优保留价;拍卖行的最优佣金率小于不设置一口价的模型中的最优佣金率.     

有色观测噪声下的多变量设置调整策略

针对存在初始设置偏差的离散的多变量生产制造过程，研究了观测噪声服从Auto-Rgressive （AR）模型的情况下，考虑调整花费成本为二次型函数时的设置调整问题，在建立过程状态空间方程的基础上，利用卡尔曼滤波方法在线估计过程的状态变量，根据随机二次型最优控制理论，得到了使过程质量损失最小的最优调整策略. 通过算例解释了最优调整策略的实现方法，并进行了仿真验证，结果表明，得到的调整策略与观测噪声为白噪声时的质量调整策略相比，能更好地减少过程总体质量损失.     

A Tight Approximation Algorithm for Multi-Vehicle CVRP with Unsplittable Demands on a Line

In this paper, the authors study the multi-vehicle capacitated vehicle routing problem on a line-shaped network with unsplittable demand. The objective is to find a transportation scheme to minimize the longest distance traveled by a single vehicle such that all the customers are served without violating the capacity constraint. The authors show that this problem has no polynomial-time algorithm with performance ratio less than 2 on condition that P ≠ NP, and then provide a 2-approximation algorithm.

     

基于Max(N,D)策略的MG1排队系统的稳态指标

考虑一个由N策略和D策略同时控制的MG1排队系统.当顾客的到达个数至少为N个同时等待顾客的服务时间之和大于某非负实数D时,空闲的服务台重新开始服务顾客(称此服务启动策略为Max(N,D)策略).在此策略下,由于闲期到达顾客的服务时间是条件相依的,故队长的随机分解不再成立.通过将顾客分成两类,并借助拉普拉斯变换和概率分析,研究了该排队系统的稳态队长分布、稳态闲期和忙期分布、稳态服务时间积压量分布以及顾客的稳态逗留时间分布.数值算例分析了N、D和Max(N,D)策略对稳态平均队长的影响.在数值上获得了系统稳态费用最小的最优策略临界值,并比较了N、D、Max(N,D)和Min(N,D)策略的优越性.     

Outpatient capacity allocation considering adding capacity to match high patient demand

This paper focuses on an outpatient capacity allocation problem where the patient demand is quite higher than the supply. We study an adding capacity policy to mitigate the mismatch between supply and demand. Under this policy, the doctor is allowed to add capacity if all regular capacity have been booked. A capacity allocation model is formulated for both possible no-show routine patients and all show-up same-day patients. The purpose is to determine the number of capacity can be added and how to allocate regular capacity among routine patients and same-day patients, towards maximizing the expected profit, which is composed of the expected income minus the cost of weighted expected doctor’s overload work caused by the adding capacity policy and the cost of rejecting patients. To achieve the aims, we prove the expected profit monotonously decreases when the number of additional capacity exceeds a threshold, and present a two-tier enumeration search algorithm to find the global optimal solution based on the proof. Numerical results indicate that the proposed policy performs well under different levels of demand higher than supply. The optimal number of the additional capacity is hardly affected by varying total expected patient demand. Additionally, under the change of no-show rate, the number of regular capacity allocated to routine patients becomes more stable, compared with the optimal scheme without considering adding capacity policy.     

考虑估值不确定和搜索成本的预售决策研究

研究了预售环境下,存在消费者估值不确定和消费者搜索成本时,销售商的最优定价和配给决策.建立一个两阶段模型,考虑一个销售商出售单一新产品给若干具有战略行为的消费者,消费者根据自身效用最大化原则选择最佳购买时机,销售商则考虑消费者的战略行为,决策最优的两期价格和预售期配给量.研究结果表明,预售期的配给量取决于单位产品的采购成本.当且仅当单位产品的采购成本介于特定范围内时,销售商应采用预售策略,此时折扣预售策略总是销售商的最佳选择.否则销售商应采用正常销售策略.研究还表明,当消费者的风险成本系数较低时,消费者的搜索成本越高,销售商的预售价格和总利润越低.否则,消费者的搜索成本越高,销售商的预售价格和总利润越高.     

A discrete-time Geo/G/1 retrial queue with J-vacation policy and general retrial times

The authors discuss a discrete-time Geo/G/1 retrial queue with J-vacation policy and general retrial times. As soon as the orbit is empty, the server takes a vacation. However, the server is allowed to take a maximum number J of vacations, if the system remains empty after the end of a vacation. If there is at least one customer in the orbit at the end of a vacation, the server begins to serve the new arrivals or the arriving customers from the orbit. For this model, the authors focus on the steady-state analysis for the considered queueing system. Firstly, the authors obtain the generating functions of the number of customers in the orbit and in the system. Then, the authors obtain the closed-form expressions of some performance measures of the system and also give a stochastic decomposition result for the system size. Besides, the relationship between this discrete-time model and the corresponding continuous-time model is also investigated. Finally, some numerical results are provided.     

Performance Analyses of Production Inventory Systems Considering Service Time and Product Returns of Online Shopping

This paper considers a production inventory system with service time and product returns,dependent on the characteristics of online shopping behaviors. The customers arrive according to a Poisson process, in which the arriving customer requires an item in the inventory, as well as a server service that the service time is exponentially distributed. Moreover, there is one production facility to produce items according to(s, S) policy, and the production time also follows an exponential distribution. In the beginning, the stationary joint distribution is obtained in the product form for the queue length and the on-hand inventory level. Additionally, the resulting distribution is applied to derive some performance measures, which can be adopted to numerically calculate the optimal(s, S)policy. Finally, numerical analyses are processed to investigate the effects of some system parameters on the performance measures. The numerical results clearly indicate that the product return rate has a significantly monotonic effect on the optimal policy and optimal cost.     

时变需求下基于两层次信用支付策略的供应链库存模型

传统的基于信用支付的供应链库存模型仅假设上游供应商给予下游零售商一个固定的信用支付期,但在实际中由于市场竞争的需要,零售商也会给予顾客相应的信用支付优惠策略.基于线性时变需求构建了两层次信用支付策略下的供应链库存模型,讨论了模型最优解的存在性及唯一性, 并提供了寻求模型整体最优解的简单方法. 最后给出了具体数值例子,对模型进行了灵敏度分析.     

平台自营业务与第三方商家的劝说性广告竞争策略

针对综合型平台自营业务和第三方商家之间的销售竞争，考虑双方进行劝说性广告投放，构建了平台自营和第三方商家在不同市场地位情况下的博弈模型，分别给出了平台自营主导，第三方商家主导以及市场地位相同时的最优决策和均衡利润，并分析了横向差异化、纵向差异化和广告服务费系数对最优决策和均衡利润的影响。研究表明：横向差异化（消费者偏好强度）越大，在平台主导和第三方商家主导的两种情况下，平台价格和广告投放水平越高；第三方商家广告投放水平降低，价格先降低后增加；双方市场地位相同情况下，平台和第三方商家的均衡价格和广告投放水平相等，并且双方的价格随消费者偏好强度增加而增加，广告投放水平与消费者偏好强度无关。纵向差异化（平台相对于第三方商家的质量差异）越大，无论市场地位情况如何，平台（第三方商家）均衡价格和广告投放水平越高（越低）。广告服务费系数并不是越高越好，只有当第三方商家主导市场且广告服务费系数达到一定水平之后，此时广告服务费系数增加才能增加平台利润。     

Towards exploring when and what people reviewed for their online shopping experiences

Web 2.0 technologies have attracted an increasing number of people with various backgrounds to become active online writers and viewers. As a result, exploring reviewers’ opinions from a huge number of online reviews has become more important and simultaneously more difficult than ever before. In this paper, we first present a methodological framework to study the “purchasing-reviewing” behavior dynamics of online customers. Then, we propose a review-to-aspect mapping method to explore reviewers’ opinions from the massive and sparse online reviews. The analytical and experimental results with real data demonstrate that online customers can be sectioned into groups in accordance with their reviewing behaviors and that people within the same group may have similar reviewing motivations and concerns for an online shopping experience.