基于风险规避和公平偏好的供应链收益共享契约协调研究

在一个简单的二级供应链系统中,建立了供应商和零售商同时具有风险规避和公平偏好的收益共享契约协调模型,通过修正、扩展FS效用收益模型,先后考察并分析了分散决策和集中决策下供应链的协调状态,研究发现,供应商和零售商的风险规避系数和公平偏好系数及收益份额必须满足特定的条件,收益共享契约才能使系统供应链整体达到协调状态;在此基础上,对风险规避和公平偏好因素进行敏感度分析,得到供应商和零售商行为偏好系数对供应链及成员最优订货量的影响;最后进行演化博弈算例分析和结论验证,体现了该协调模型的有效性和实用性。由此说明供应商和零售商的风险规避和公平偏好因素同时作用会改变系统供应链协调时的最优订货量,并对决策人的决策行为产生很大的影响。     

考虑公平关切行为下竞争零售商的最优联合购买策略研究

本文考虑一个由两个竞争的零售商和一个供应商组成的两级供应链,其中供应商可通过提供批量折扣契约向两家竞争的零售商销售产品,而零售商表现出纵向公平关切(即当获得利润小于供应商的利润时,其获得一个负效用)。并且,考虑的两个零售商为了获得较低的批发价格可能更喜欢团购,进而它们将选择最佳订单数量来最大化其自身的效用。利用经典的纳什议价解决方案作为公平参考点,本文主要研究竞争与公平关切行为将如何影响零售商的联合购买策略。研究发现,当零售商追求公平时,联合购买策略优于单独购买策略,且越大竞争强度使得使用联合购买策略的优势越明显。此外,当零售商表现出不同的公平关切程度时,若批量折扣比例比较低,对公平关切敏感的零售商的效用总是小于对公平关切不敏感的零售商的效用;否则,对公平关切敏感的零售商的效用总是大于对公平关切不敏感的零售商的效用。     

基于损失厌恶型参与者的易逝品供应链价格补贴契约研究

本文运用前景理论,探讨存在缺货损失情况下由损失厌恶型零售商和损失厌恶型供应商组成的供应链价格补贴契约设计。文章研究供应商为损失厌恶型时,损失厌恶型零售商分别在批发价格契约和价格补贴契约下的订货行为。研究结果表明损失厌恶型零售商在批发价格契约下的最优订货量可能偏离系统最优订货量,损失厌恶型供应商通过价格补贴契约可以协调整个供应链。最后通过算例分析,验证了价格补贴契约在协调供应链中的有效性。     

考虑公平关切的供应链契约与协调

供应链契约是影响供应链整体绩效的重要因素.在传统两阶段供应链中引入公平关切,研究了公平关切行为倾向对供应链契约与协调的影响.文中假设零售商是公平关切的,在此假设下展开行为运筹分析,分别探讨了零售商的公平关切行为倾向对批发价契约,收益共享契约和回购契约等协调性的影响,并用算例加以验证.最后,在此基础上提出并证明了一般性结论:零售商的公平关切不会改变供应链的协调状态.     

模糊需求下考虑公平关切的收益共享契约与协调

针对供应链收益分配过程中零售商往往表现出公平关切行为,研究了模糊需求环境下两级供应链的收益共享契约与协调问题。在给出模糊市场需求环境下的收益共享契约基本模型的基础上,构建了考虑零售商公平关切的收益共享契约模型,并通过模型推导及数值实验分析了零售商公平关切对收益共享契约协调供应链的影响。研究结果表明,模糊需求下考虑零售商公平关切的收益共享契约仍然可以实现供应链协调,然而零售商的公平关切行为对收益共享契约的协调策略会产生影响。本文的研究成果可为供应链成员优化收益共享契约提供参考价值。     

Nash讨价还价公平关切下基于低碳商誉的供应链联合减排与广告的动态优化与协调

基于Nash讨价还价理论构建公平效用体系,同时考虑产品低碳水平和低碳商誉具有动态变化特征,运用微分博弈理论与方法探讨了供应链成员的公平关切行为对分散决策下零售商广告策略和制造商减排策略的影响以及集中决策下的相关策略。通过对比发现,集中决策下产品的低碳水平更高,在此基础上,提出了双向成本分担契约,实现了供应链协调。最后通过数值仿真,对重要参数进行了敏感性分析,并验证了契约的有效性。研究发现：当制造商边际利润比较小时,制造商不会对减排进行投入;只有当满足一定条件时,制造商才会承担零售商的广告成本;制造商的公平关切行为不利于企业发展低碳经济;零售商适当地关注公平,有利于企业发展低碳经济;与分散决策相比,双向成本分担契约下制造商和零售商的效用以及利润现值均有所提升。     

碳限额与碳交易机制下考虑公平关切的供应链定价与协调研究

供应链企业的公平关切是发展与维持良好供应链上下游合作关系的重要因素。面对消费者的低碳偏好与碳排放规制约束,供应链企业在确定最优定价与减排水平等运作决策时,常常表现较强的公平关切倾向。探究环保规制下公平关切如何影响供应链的运作决策,可以为供应链合作提供对策。本文在碳限额与碳交易机制下,研究了由公平关切制造商和公平关切零售商组成的低碳供应链的最优定价和碳减排率等决策,分析了公平关切对最优定价和碳减排水平及利润的影响,并讨论了收益共享-成本共担契约模型对供应链的协调性,最后通过数值仿真验证了主要结论。结果表明：(1)制造商和零售商都公平关切时,收益共享-成本共担契约的参数若满足一定条件,供应链可以实现协调。(2)批发价与制造商公平关切系数正相关,零售价与制造商和零售商公平关切系数都正相关;若制造商考虑零售商公平关切则批发价的变化取决于碳减排成本系数的大小,碳减排率与制造商和零售商的公平关切系数是负相关;若制造商忽视零售商的公平关切,则批发价仅受制造商自身公平关切的影响, 碳减排率与制造商公平关切负相关,与零售商公平关切无关。(3)制造商公平关切对双方利润具有负向影响,零售商公平关切对制造商利润也有负向影响,而零售商利润随自身公平关切的变化情况取决于制造商是否考虑其公平关切,若考虑则两者正相关,否则两者负相关。     

供应突发事件下基于CVaR的供应链订货决策及协调

供应突发事件下,引入条件风险值(conditional value at risk-CVa R)刻画了零售商的运营目标,构建了收益共享契约下的供应链订货模型,着重研究了CVa R下的供应链协调及零售商最优订货量对供应商可靠性及对其自身的风险规避系数的敏感性。研究表明:收益共享契约具有一定的鲁棒性,能协调突发事件风险下的供应链;风险规避型零售商的最优订货量总是不小于风险中性情况,且风险规避程度越高,订货量越大;最优订货量对供应商可靠性均值的敏感性不依赖于零售商的风险规避程度,且均值越小,最优订货量越大,这与风险中性情况是类似的;最优订货量对供应商可靠性标准差的敏感性则依赖于零售商的风险规避程度,当零售商的风险规避程度较高时,供应可靠性标准差越大,最优订货量越大,这与风险中性情况是相反的。     

考虑损失厌恶—对多型供应链的收益共享契约

以一个两阶段的供应链系统为研究背景,建立了下游损失厌恶型零售商之间存在竞争的收益共享契约协调模型.研究发现,竞争性的多零售商之间存在唯一的纳什均衡总订货量使其期望效用实现最大化,且总订货量随零售商数目的增加而增加、随零售商风险厌恶程度的增加而减少.在此基础上,进一步分析了在整个供应链系统中存在唯一的“批发价一收益共享系数”比值能够使供应链利用收益共享契约达到协调,并推导了系统实现协调时最优契约参数之间的关系;最后结合数值实例验证了供应链收益共享契约机制的有效性.     

公平关切及低碳视角下供应链两部定价契约问题研究

低碳环境下,碳排放权作为一种有价值、可交易的稀缺性资源,已彻底颠覆了传统企业的竞争法则、成本构成及盈利模式,被视为低碳时代供应链契约优化与协调的主要对象。文章利用博弈论等相关知识,考虑公平关切及低碳视角下,由一个制造商和一个零售商组成的供应链,分别讨论了当零售商不具有公平偏好及具有公平偏好时,面对有利和不利不公平分配的制造商向零售商提供两部定价契约能否达成协调？以及达成协调时的供应链契约协调参数设置等问题。研究结果表明,只有在制造商和零售商都具有公平偏好,且在竞争型供应链渠道下,当制造商面对不利不公平分配的单位负效用大于某一临界值时,供应链两部定价契约不能达成协调。     

Educational Landscapes and Urban Development. Contextual and Spatial Interfaces and Linkages

In the broad sociopolitical discussion on education quality within the last decade, it has become apparent that education is gaining importance for urban development, as well as space and the urban context are important dimensions of education. This becomes particularly evident in concepts for local educational landscapes (Ger. Bildungslandschaften). The young field of research on educational landscapes is currently lacking empirical research from spatial and planning sciences. In the paper, the current state of scientific research on educational landscapes in Germany and Europe and first insights to contextual and spatial interfaces and linkages between education and urban development in general are presented.     

Inventory Models with Continuous and Poisson Demands and Discounted and Average Costs

We develop a new, unified approach to treating continuous‐time stochastic inventory problems with both the average and discounted cost criteria. The approach involves the development of an adjusted discounted cycle cost formula, which has an appealing intuitive interpretation. We show for the first time that an (s, S) policy is optimal in the case of demand having a compound Poisson component as well as a constant rate component. Our demand structure simultaneously generalizes the classical EOQ model and the inventory models with Poisson demand, and we indicate the reasons why this task has been a difficult one. We do not require the surplus cost function to be convex or quasi‐convex as has been assumed in the literature. Finally, we show that the optimal s is unique, but we do not know if optimal S is unique.     

E-governance and Corruption-developments and Issues in Ethiopia

This paper reports the results of a survey of 400 respondents in Ethiopia about factors generating corruption and the potential of e-Governance to mitigate corruption. It is suggested that e-Governance can help not only in weeding out corruption but also in the establishment of sounder government citizen relationships in Ethiopia. While e-Governance cannot cure all the structural factors that breed corruption in the society, strategic implementation of e-Governance can help improve the critical variable in combating corruption-government citizen relationships. It is argued that while e-Governance initiatives can make important contributions to improving public services they can best do so by helping improve overall relationships between governments and citizens.

The Challenge of Political and Economic Change in Poland and Central and Eastern Europe

This article discusses political and economic changes in Poland, Central and Eastern Europe emerging since the demise of the ‘closed system’ in 1989. The presentation explores the range of change, the method and the sequence of change. General lessons in economic transition as identified by Polish Finance Minister Lezak Balcerowicz are discussed. The challenges involved in macroeconomic stabilization, radical liberalization, currency convertibility, subsidy reduction and conversion of state-owned enterprises are reviewed. Despite their complexity, economic and political reforms proved necessary and inevitable. This revised version was published online in July 2006 with corrections to the Cover Date.     

Chronic stress and chronic disease in life and work: Conceptual and methodological issues

This paper argues that the lack of strong prospective evidence linking occupational and social stress to chronic disease stems from the failure of research designs to attend sufficiently to the aetiological chronicity of such diseases. Studies of both supposedly acute stress (life events) and chronic stress in life or work must increasingly be designed to distinguish between stress which is sustained or chronic over a period of yean or even decades, and hence capable of causing a serious chronic disease, and brief or transient stress, which may produce transient or brief psychological or physiological disturbances but cannot generate major chronic disease. Prospective studies are needed which collect measures of both stress and health or disease at multiple points over an extended period of time. Measures of stress should focus more on affect (for example, feelings of pressure and tension) than on cognition (for example feelings of satisfaction). Limited existing evidence is consistent with these ideals.     

Beliefs and the Perception of Risks and Accidents

Identifying the causes of accidents is a necessary prerequisite for preventive action. Some research suggests however that the analysis of accidents does not only differ between experts and laymen but that it is also linked to certain characteristics inherent in the analyst and in the social group to which he belongs: beliefs, value systems, norms, experiences in common, attitudes, roles, social and technical practices, etc. Culturally determined bias seems to affect the perception of risk and the causes of accidents. This article presents a certain number of thoughts and results based upon research carried out on causal attributions of traffic accidents in The Ivory Coast (West Africa) and discusses the importance of culture in risk-taking and accident prevention. It shows in particular that fatalistic beliefs and mystical practices influence the perception of accidents and consequently incite one to take more risks and neglect safety measures.     

Work and shopping overflow — Consequences and differentiation among selected psychological and demographic characteristics

Contemporary individuals are forced to deal with excessive stimulation, which causes an overload in the cognitive and emotional areas. The purpose of this paper is to investigate the possible factors differentiating the perceived level of work and shopping overflow experienced by individuals and consequences of these states. Two psychological variables: cognitive control and sensation seeking, are chosen as potential factors differentiating the perceived levels of overflow. We assume that individuals with high cognitive control and sensation seeking will report lower levels of both types of examined overflows. Experiencing low overflow levels may manifest in the search for additional stimuli, rather than in the desire to limit them. Two indexes of behavior connected to seeking extra stimulation are selected: one belonging to the area of consumer behavior (readiness to participate in the experience economy) and one belonging to vocational behavior (choosing a boundaryless career). The quantitative study is conducted on a sample of 297 management students who are currently employed. The research results support the relation between cognitive control and perceived level of work and shopping overflow. Individuals who can cognitively control the situation and the incoming stimuli report lower levels of overflow. No significant relationship between sensation seeking and the level of overflow is found. The demographic variables that influence the perceived overflow are age and salary for work overflow and age for shopping overflow. As far as consequences of overflow are concerned, a low level of shopping overflow is related to readiness to participate in the experience economy. However, there is no link between work overflow and preferred career pattern. The managerial implications for human resource management and marketing strategy design are discussed.     

Review and preview of productivity research and applications

During the last two decades, productivity research and applications have not been given adequate importance when trying to attain excellence in the management of manufacturing enterprises. Recent developments in managerial philosophies Total Quality Management and Business Process Re-engineering , manufacturing technologies Flexible Manufacturing Systems, Computer Integrated Manufacturing, etc. and Information Technology innovations have made the traditional productivity improvement techniques obsolete. This article presents a review consisting of analyses of literature on productivity and a survey of manufacturing enterprises. A five-step preview strategy on productivity is enumerated which provides a meaningful direction towards future productivity research and application. The article is concluded by briefly describing the current research that is being carried out based on the preview strategy evolved.     

Additive and Multiplicative Models and Multistage Carcinogenesis Theory

In light of the Armitage-Doll multistage carcinogenesis theory, this paper examines the assumption that an additive relative risk relationship is indicative of two carcinogens that affect the same stage in the cancer process. We present formulas to compute excess cancer risks for a variety of patterns for limited exposure durations to two carcinogens that affect the first and penultimate stages; and using an index of synergy proposed by Thomas (1982), we find a number of these patterns to produce additive, or nearly additive, relative risk relationships. The consistent feature of these patterns is that the two exposure periods are of short duration and occur close together.     

Floods and Climate Change: Interactions and Impacts

Whether the floods experienced during the last decade in Germany and in other European countries are triggered or worsened by human activities has been the subject of a great deal of debate. Possible anthropogenic activities leading to increased flood risk include river regulation measures, intensified land use and forestry, and emissions of greenhouse gases causing a change in the global climate. This article discusses the latter by reviewing the existing knowledge on the subject. First, the relevance, capabilities, and limitations of climate models for the simulation and analysis of flood risk under aspects of the anthropogenic climate change are described. Special consideration is given here to differences between the "typical" spatial scale of climate models and hydrological flood models. Second, observations of trends in climate variables relevant for river flooding issues are summarized. Special emphasis is put on the Rhine and other German catchment areas. Third, the possibilities of modeling the different parts of the "cascade of flood risk" are summarized, introducing the special features of meteorological, hydrological, and river hydraulic models.