Online marketing: When to offer a refund for advanced sales

Advance selling is a marketing strategy commonly used by online retailers to increase sales by exploiting consumer valuation uncertainty. Recently, some online retailers have started to allow refunds on products sold in advance. On the one hand this reduces the net advance sales, but on the other hand it allows a higher advance sales price. This research is the first to explore the overall effect of allowing a refund on profits from advance sales, identifying conditions where advance selling with or without refunds (or no advance selling at all) is best. We analytically compare the profits of three advance selling strategies: none, without refund, and with refund. We show that selling in advance and allowing a refund is optimal for products with a relatively small profit margin and small strategic market size, and that the added profit can be considerable. Our results guide managers in selecting the right advance selling strategy. To facilitate this, we graphically display, based on the two dimensions of regular profit margin and strategic market size, under what conditions the different strategies are optimal.     

Individually rational rules for the division problem when the number of units to be allotted is endogenous

We study individually rational rules to be used to allot, among a group of agents, a perfectly divisible good that is freely available only in whole units. A rule is individually rational if, at each preference profile, each agent finds that her allotment is at least as good as any whole unit of the good. We study and characterize two individually rational and efficient families of rules, whenever agents' preferences are symmetric single-peaked on the set of possible allotments. Rules in the two families are in addition envy-free, but they differ on whether envy-freeness is considered on losses or on awards. Our main result states that (a) the family of constrained equal losses rules coincides with the class of all individually rational and efficient rules that satisfy justified envy-freeness on losses and (b) the family of constrained equal awards rules coincides with the class of all individually rational and efficient rules that satisfy envy-freeness on awards.     

Dynamic management of aircraft stand allocation

This paper aimed to present an original approach for solving the aircraft stand allocation (SA) problem dynamically when due to operational disturbances, the planned allocation cannot be accomplished. The proposed Multiple-criteria Dynamic Stand Allocation (MDSA) method uses fuzzy logic to support decision-making under uncertainty. The MDSA method provides effective solutions in a short time, necessary for traffic management in case of delays, emergency, and untypical cases. It considers partially conflicting points of view of different airport users (airport managers, air traffic controllers, airlines, handling agents, and passengers) and may significantly support managers on the SA problem. The approach proposed can also be used for creating an initial SA plan for a considerable number of aircraft.     

Periodic strategies in optimal execution with multiplicative price impact

We study the optimal execution problem with multiplicative price impact in algorithmic trading, when an agent holds an initial position of shares of a financial asset. The interselling decision times are modeled by the arrival times of a Poisson process. The criterion to be optimized consists in maximizing the expected net present value of the gains of the agent, and it is proved that an optimal strategy has a barrier form, depending only on the number of shares left and the level of the asset price.     

An extended likelihood framework for modelling discretely observed credit rating transitions

The estimation of the parameters of a continuous-time Markov chain from discrete-time observations, also known as the embedding problem for Markov chains, plays in particular an important role for the modeling of credit rating transitions. This missing data problem boils down to a latent variable setting and thus, maximum likelihood estimation is usually conducted using the expectation-maximization (EM) algorithm. We illustrate that the EM algorithm is likely to get stuck in local maxima of the likelihood function in this specific problem setting and adapt a stochastic approximation simulated annealing scheme (SASEM) as well as a genetic algorithm (GA) to combat this issue. Above that, our main contribution is to extend our method GA by a rejection sampling scheme, which allows one to derive stochastic monotone maximum likelihood estimates in order to obtain proper (non-crossing) multi-year probabilities of default. We advocate the use of this procedure as direct constrained optimization (of the likelihood function) will not be numerically stable due to the large number of side conditions. Furthermore, the monotonicity constraint enables one to combine structural knowledge of the ordinality of credit ratings with real-life data into a statistical estimator, which has a stabilizing effect on far off-diagonal generator matrix elements. We illustrate our methods by Standard and Poor’s credit rating data as well as a simulation study and benchmark our novel procedure against an already existing smoothing algorithm.     

预包装食品标签常见问题分析及建议

预包装食品标签作为展示产品质量重要内容之一,主要展示了食品生产者、质量指标、营养指标等信息,是消费者选购食品的主要参考依据。本文依据常用的国家标准及相关法律法规,对预包装食品标签常见问题及原因进行分析,并提出建议,为食品生产企业规范食品标签提供参考,也为食品安全监管部门日常监管提供一定的技术支持。     

NTRU格上高效的身份基线性同态签名方案

针对现有的格上身份基线性同态签名方案密钥存储量大、结构复杂导致方案实际运行效率相对偏低的问题，提出了一个NTRU（Number Theory Research Unit）格上高效的身份基线性同态签名方案。首先在密钥生成阶段利用NTRU密钥生成算法产生主密钥，接着采用格基委派算法给出身份签名私钥，最后运行NTRU格上原像抽样算法产生出线性同态签名。对方案的安全性证明与性能分析结果表明，新方案满足正确性，具有弱内容隐私性。在随机预言机模型下，该方案在小整数解问题困难性条件下满足适应性选择身份和选择消息的存在性不可伪造性。同时，由于采用NTRU格的特殊结构，新方案在密钥量与运行效率方面与已有方案相比较均具有显著的优势，这对于计算资源受限环境的同态认证中具有重要的应用价值。     

Robust consumption‐investment problem under CRRA and CARA utilities with time‐varying confidence sets

We consider a robust consumption‐investment problem under constant relative risk aversion and constant absolute risk aversion utilities. The time‐varying confidence sets are specified by Θ, a correspondence from [0, T] to the space of the Lévy triplets, and describe a priori drift, volatility, and jump information. For each possible measure, the log‐price processes of stocks are semimartingales, and the triplet of their differential characteristics is almost surely a measurable selector from the correspondence Θ. By proposing and investigating the global kernel, an optimal policy and a worst‐case measure are generated from a saddle point of the global kernel, and they constitute a saddle point of the objective function.     

国企多任务努力成本相关下的高管激励问题

本文在Holmstrom和Milgrom多任务委托代理模型的分析框架下,建立国有企业的三任务模型,探讨国企多任务努力成本相关下高管激励问题。研究发现,当多任务为互补时,实现企业社会责任目标会对企业经济性任务产生互补促进性作用,有利于经济性任务目标的实现,增加可观测性较高的任务激励会带来互补性任务绩效的提高。当多任务为替代时,实现企业社会责任目标会对企业经济性任务目标的实现产生阻碍作用,不利于经济性任务目标的实现,增加可观测性较高的任务激励会带来互补性任务绩效的减少。当多任务为不相关时,任务间努力成本互相独立,实现企业的政策性任务与其他任务努力成本不相关,应剥离政策性任务。该结论对于国有企业的任务选择与指派,以及存在多任务时的激励机制设计具有重要参考价值。     

上市公司发放现金股利的价值效应——基于委托代理问题视角的实证研究

现金股利发放反映了债权人、股东、管理者之间的利益分配关系,现金股利的价值效应受到委托代理问题的影响。采用2008—2017年沪深A股上市公司作为研究样本,在委托代理理论的分析框架下实证检验我国上市公司发放现金股利的价值效应。研究表明,发放现金股利可能会损害债权人利益,过度债务公司发放现金股利的价值效应较小,而债务不足公司发放现金股利的价值效应较大。基于管理者代理问题视角的研究发现,现金股利可以有效发挥降低管理者代理成本的作用,当管理者代理问题严重时公司发放现金股利的价值效应更大。基于控股股东代理问题视角的实证结果表明,现金股利可以作为替代性的治理机制约束控股股东行为,当控股股东代理问题严重时现金股利具有更高的价值效应。