A note on “Coordinating a supply chain for deteriorating items with a revenue sharing and cooperative investment contract”

In this short note, we first improve the proof in Zhang et al. [1] to show the strict concavity of the unit time total profit of the whole supply chain with respect to preservation technology investment without approximation. We then generalize the model of Zhang et al. [1] to a broader class of market demand functions. Additionally, theoretical results are provided to illustrate the features of the proposed model.     

A multiple warm standby δ-shock system with a repairman having multiple vacations

In this article, a warm standby n-unit system is studied. The system is operational as long as there is one unit normal. The unit online, which has a lifetime distribution governed by a phase-type distribution, is also attacked by a shock from some external causes. Assume that shocks arrive according to a Poisson process. Whenever an interarrival time of shock is less than a threshold, the unit online fails. The lifetimes of the units in warm standby is exponentially distributed. A repairman who can take multiple vacations repairs the failed units based on the “first-in-first-out” rule. The repair times and the vacation times of repairman are governed by different phase-type distributions. For this system, the Markov process governing the system is constructed. The system is studied in a transient and stationary regime; the availability, the reliability, the rates of occurrence of the different types of failures, and the working probability of the repairman are calculated. A numerical application is performed to illustrate the calculations.     

协调：一种应对公共政策执行阻滞现象的理念——基于公共政策执行中中央与地方的博弈分析

现有研究所提出的消解公共政策执行阻滞现象的对策多为事后性对策，且偏于刚性方式。以博弈论为理论依据，通过建构传统策略下中央与地方的策略互动、“协调”作为中央策略下的策略互动、协调引入博弈最始端下的策略互动三个博弈模型，比较得出将协调引入公共政策的制定和执行中，将有助于公共政策执行阻滞现象的减少和消除，并在此基础上提出以协调为理念构建的对策。     

电商闭环供应链中的“让利”公平关切回收决策研究

针对单一再造商和单一电商平台构成的两阶段电商闭环供应链,本文研究了电商闭环供应链的三种回收决策模型：再造商无公平关切的分散决策模型、再造商让利公平关切的分散决策模型以及联合决策模型。然后,求解分析模型,给出每种模式的最优回收策略,并对三种模式的最优决策进行比较分析。在此基础之上,进一步设计电商闭环供应链的"回收成本共担联合收益共享"契约,实现系统的协调。最后,采用数值分析对模型结论进行验证。研究发现：（1）再造商的公平关切行为是一种"让利"行为：虽然对自身收益不利,但是对电商平台和消费者都有利,当让利公平关切程度不高于0.5时,对系统利润起到促进作用,但是当让利程度超高0.5时,会造成系统利润下降。因此再造商往往迫于一定的压力实施让利公平关切,并且让利程度有限,一般不超过0.5。从长远来看,再造商的让利公平关切能够稳固EC-CLSC的稳定运行。（2）联合决策下,废旧品回收价格达到最高,电商平台佣金最低,系统利润最优,采用文章设计的"回收成本共担联合收益共享"契约可以实现系统协调。（3）在协调机制中,再造商分担电商平台的成本比例恰好等于分得的系统利润比例。而且随着佣金的降低,再造商分担电商平台服务成本的比例和电商平台分享再造商收益的比例均会增加。这些结论丰富完善了电商闭环供应链的理论基础,为电商闭环供应链成员的决策提供一定的理论参考。     

企业无力清偿欠薪的法律应对:基于香港的经验

1980-1982年经济危机爆发后,香港因大量企业倒闭引发欠薪浪潮,欠薪优先权机制出现失灵.以国外经验为模本,香港构设了欠薪保障基金制度.该制度依托完善的法律程序将欠薪纳入专门基金予以垫付,并逐渐提高垫付标准.这种法律设计特点鲜明,实际运行数据也证明比较成功.这为解决当前农民工极端讨薪事件频发、欠薪问题季节性爆发的顽疾,提供了极具参考价值的制度化思路.我国应当鼓励地方探索和构建企业欠薪保障制度.     

政策学习视角下地方科技政策与气候政策协调——以武汉为例

政策学习是政策变迁的主要动力,政策协调实际上是政策参与者通过政策学习实现政策融合的过程和结果。中国地方公共政策不协调的情况比较普遍,其中科技政策与气候政策的协调问题具有代表性。运用政策学习的理论框架,分析武汉市低碳试点中科技政策和气候政策的学习历程,发现武汉政策参与者的学习主要是对外部经验的学习,尚处于初级阶段,学习的平台也比较欠缺。解决这些问题,需要构建政策网络,促进政策信念的学习,创新运用政策工具,开展低碳技术政策评估。     

基于模糊理论评估连续梁桥地震破坏状况

为了研究不同强度等级地震作用下连续梁桥的破坏模式及破坏程度,采用多级模糊综合评判方法建立连续梁桥的综合评估模型。根据连续梁桥的特点,利用连续梁桥各单元及各构件的破坏程度建立多个因素集,根据各因素的权重和评价标准,对多个因素集进行逐级评判,根据最大隶属度原则得到地震作用下连续梁桥的破坏情况,并通过等级参数评判法对不同地震强度下连续梁桥的破坏情况进行等级评判,得到连续梁桥破坏情况与地震强度之间的关系。最后,基于多级模糊综合评判方法对一座连续梁桥实例进行评判     

Robust Smoothed Rank Estimation Methods for Accelerated Failure Time Model Allowing Clusters

Smoothed Gehan rank estimation methods are widely used in accelerated failure time (AFT) models with/without clusters. However, most methods are sensitive to outliers in the covariates. In order to solve this problem, we propose robust approaches based on the smoothed Gehan rank estimation methods for the AFT model, allowing for clusters by employing two different weight functions. Simulation studies show that the proposed methods outperform existing smoothed rank estimation methods regarding their biases and standard deviations when there are outliers in the covariates. The proposed methods are also applied to a real dataset from the “Major cardiovascular interventions” study.     

Influence diagnostics for the Weibull-Negative-Binomial regression model with cure rate under latent failure causes

In this paper, we propose a flexible cure rate survival model by assuming that the number of competing causes of the event of interest follows the Negative Binomial distribution and the time to event follows a Weibull distribution. Indeed, we introduce the Weibull-Negative-Binomial (WNB) distribution, which can be used in order to model survival data when the hazard rate function is increasing, decreasing and some non-monotonous shaped. Another advantage of the proposed model is that it has some distributions commonly used in lifetime analysis as particular cases. Moreover, the proposed model includes as special cases some of the well-know cure rate models discussed in the literature. We consider a frequentist analysis for parameter estimation of a WNB model with cure rate. Then, we derive the appropriate matrices for assessing local influence on the parameter estimates under different perturbation schemes and present some ways to perform global influence analysis. Finally, the methodology is illustrated on a medical data.     

中美铁路行业治理制度及其效率的比较分析

本文从铁路行业治理的视角,以铁路企业间的相互依赖性及其行业内协调制度为分析对象,分析中美铁路行业治理制度环境的相似性与差异性,探讨中美铁路行业内协调的制度安排的细节及其差异性,并运用比较制度分析的理论研究中美铁路行业内运营协调的信息体制及其效率差异,分析其清算制度的不同激励效果与适应性差异,阐述其对中国铁路重组的启示。