考虑佣金的关联价值拍卖模型

在标准的只考虑买卖双方的拍卖模型中引入第三方,拍卖公司.拍卖公司提供服务要收取一定的佣金,佣金费用由买家支付,支付额占成交价的比例为k.文章发现,佣金比例k的大小对买卖双方均有一定影响:买方的出价策略变得谨慎但是其均衡期望收益却与k无关;卖方的期望收益受到影响而降低.事实上,拍卖公司的佣金就是来自于卖方的期望收益中.文中就第一价格与第二价格机制在关联价值模型上讨论佣金问题,得到的结果有较普遍的意义.     

拍卖中的串通出价

本文在扩展的独立私有价值模型下,考虑第二价格和第一价格拍卖机制下的串通出价行为和卖方对串通出价的反映。第二价格串通出价机制和第一价格串通出价机制分别为在这两种拍卖机制下的激励相容、有效的直接显示串通出价机制。我们发现卖方若知道有串通行为,可以提高保留价来减少损失。由于卖方一般情况下不太可能确定是否存在串通行为及参与串通的人数k,但可以确定给定保留价时串通人数的'最优反应',在第二价格串通出价机制下,给定串通人数,增加保留价可以提高卖方的期望收益,对于确定的保留价,串通人数的增加会减少卖方的期望收益。从而存在这样的纳什均衡:所有的投标人串通,即,k=N,而卖方宣布与之相应的保留价r (N)。当然,并不是所有的串通出价对投标人都是有利可图的,在第一价格拍卖机制下,若卖方可以调整保留价,只有当参与竞投的人很多时,串通出价才有利可图。     

带佣金率和保留价的一级和二级价格拍卖

本文通过引入佣金率和保留价,分别讨论了一级和二级价格密封式拍卖,得到以下结论:(1)两种密封式拍卖的均衡报价随佣金率的提高而减少;(2)一级价格密封式拍卖的均衡报价随保留价的增加而增加,而二级价格密封式拍卖的均衡报价随保留价的增加而减少;(3)一级价格密封式拍卖的投标者预期收益与佣金率和保留价均呈反向变动,而二级价格密封式拍卖的投标者预期收益独立于佣金率和保留价;(4)收益等价定理仍然成立;(5)在两种密封式拍卖中,当佣金率增加时,卖方的预期收益减少,拍卖行的预期收益以及卖方和拍卖行的总预期收益可能增加也可能减少;(6)在两种密封式拍卖中,当保留价增加时,卖方的预期收益、拍卖行的预期收益以及卖方和拍卖行的总预期收益可能增加也可能减少;(7)给出了卖方的最优保留价的表达式;(8)把本文的结论与以前相应的研究工作做了比较。     

基于Priceline的买方/卖方定价收益管理问题

以著名逆向拍卖网站 Priceline 为背景,研究买方定价和卖方定价下的收益管理问题.假定顾客到达是一任意的更新过程,决策时刻为顾客到达时刻,所以决策是离散时间的.建立了两种定价方式下的马氏决策过程模型,获得了最优策略的表达式.在传统收益管理问题中,通常是卖方定价、连续时间决策、同时需要假定顾客到达是一 Poisson 过程.对于买方定价,文中证明了,卖方是否知道到达顾客的报价信息不影响他的收益;同时,随着剩余物品数的增加,卖方的期望收益递增,而边际收益递减,最优价格(或报价)递减.文中讨论两种定价方式下卖方的期望收益之间的关系.考虑了顾客需求是多重的情形.最后,数值分析表明文中所得的结论是成立的.     

基于信号博弈的卖方欺诈行为分析

本文主要基于信号博弈的卖方欺诈行为进行研究，假设拍卖中可能存在欺诈型和诚实型两种卖家，其中欺诈行为有概率发生在第二价格拍卖中：欺诈型卖方冒充竞拍者递交仅次于最高价的报价从而获得额外收益。两种卖家根据各自效用选择拍卖形式：第一价格或者第二价格。而竞买者将卖者的选择作为信号，更新对卖方类型的判断，然后制定报价策略。这是一个买卖方信号交叉影响的过程。考虑到拍卖过程中买方价值相关性，本文在建立模型中参考了关联价值原理。针对该模型进行分析，得出了不同情况下的买卖方策略，并且研究了买方报价、买方判断、卖方收益三者之间的关系。文中利用贝叶斯公式对双方的策略选择问题进行预测，与单纯的概率分布方法相比，更具实践价值。     

基于幂效用函数的多属性英式拍卖研究

以采购问题为背景研究多属性拍卖问题,其中拍卖问题的特点是：（1）包含任意有限个属性;（2）买卖双方的效用函数均具有加性结构,且在除价格以外的单个属性上,买方的效用函数和卖方的成本函数均为一般幂函数形式。首先,设计了一种买方事先公布评分函数而卖方轮流提交投标的多属性英式拍卖机制;其次,在卖方对称的假设下分析了拍卖机制中的最优投标策略,确定了最优投标价格和最优非价格属性值;然后,分析得出了最具成本优势的卖方最终胜出的条件以及最优多属性投标;最后,计算了该拍卖机制中买方的期望收益,并求出了使其期望收益最大化的最优评分函数权重。     

偏向制造商多买方e-供应链的博弈及其影响因素分析

对单个制造商多个同质买方的供应链系统,市场需求为价格弹性不确定需求,假设买方之间进行Cournot博弈,并和制造商进行Slackelberg博弈,建立了偏向制造商的的e-供应链模型.发现在偏向制造商的e-供应链中,制造商和买方的竞争优势增强;买方的数目增加,对制造商有利而对买方不利;第三方信息平台的佣金率增加时,制造商的收益减少;买方能接受的佣金率随其数目的增加而变小;最后通过算例对所得到的结论进行了验证.     

基于双边减排成本信息不对称的排污权二级交易市场拍卖机制研究

本文构建了一个基于双边减排成本信息不对称的排污权二级交易市场拍卖模型,分析了统一价格、歧视价格及混合拍卖机制下卖方收益、排污权价格波动及排污权供给量差异,在此基础上给出了排污权二级交易市场最优拍卖机制,并进一步讨论了相关参数对最优拍卖机制的影响。结果表明：从收益最大化角度来看,最优的拍卖机制为歧视价格拍卖机制,但考虑到价格波动及排污权供给量等其他因素,排污权二级市场交易应选用混合拍卖机制。风险偏好变化对混合拍卖机制下卖方收益及价格波动的影响存在不确定性,当风险偏好超过某一阈值时,随着风险偏好程度增大,需求隐蔽效应占主导,收益及价格波动增大;相反,当风险偏好小于某一阈值时,随着风险偏好程度增大,竞争效应占主导,收益及价格波动减小。价格变动的供给影响系数对卖方收益的影响随买方参与人数的不同而不同。当买方参与人数较小时,需求隐蔽效应占主导,竞争效应不明显,随着价格变动的供给影响系数增大,混合拍卖机制下卖方的收益不断增加;当买方参与人数较大时,卖方收益同时受到需求隐蔽和竞争效应影响,随着价格变动的供给影响系数增大,收益呈先增大后减小趋势。随着价格变动的供给影响系数增大,价格波动呈先增大后减小趋势。     

非对称情况下的多物品拍卖

本文讨论当投标人之间存在不同的预算约束时两物品的序贯增价拍卖,对于物品之间不同的关系(互补、替代或者不相干的关系),物品价值大小的不同及与预算大小之间的关系,在一个简单的完全信息模型下,我们分不同情况讨论投标人的均衡出价策略,并发现对卖方来说,先拍卖价值高的物品是弱占优的策略。     

考虑供应风险和生产成本不确定性的供应链动态决策研究

考虑到供应风险和生产成本的不确定性,本文研究了买方或卖方实施努力既可能改善供应可靠性,同时又可能降低生产成本的供应链最优决策问题。分别构建了制造商努力和供应商努力的两阶段动态决策模型。分析了提升供应可靠性和降低成本的概率对两种模型中的最优采购数量、最优努力程度和上下游期望收益以及供应链期望收益的影响。同时在两种模型的比较中发现,制造商的最优努力与供应商的最优努力之间的差异与收益分享系数有关。相同努力效果下,制造商努力时的最优采购数量总是不小于供应商努力时的最优采购数量。相比供应商努力,制造商努力更有利于增加其自身的期望收益。然而,供应商以及整个供应链的期望收益却可能在供应商努力时更高。     

Introduction to Special Section on Sensitivity Analysis and Summary of NCSU/USDA Workshop on Sensitivity Analysis

This guest editorial is a summary of the NCSU/USDA Workshop on Sensitivity Analysis held June 11–12, 2001 at North Carolina State University and sponsored by the U.S. Department of Agriculture's Office of Risk Assessment and Cost Benefit Analysis. The objective of the workshop was to learn across disciplines in identifying, evaluating, and recommending sensitivity analysis methods and practices for application to food‐safety process risk models. The workshop included presentations regarding the Hazard Assessment and Critical Control Points (HACCP) framework used in food‐safety risk assessment, a survey of sensitivity analysis methods, invited white papers on sensitivity analysis, and invited case studies regarding risk assessment of microbial pathogens in food. Based on the sharing of interdisciplinary information represented by the presentations, the workshop participants, divided into breakout sessions, responded to three trigger questions: What are the key criteria for sensitivity analysis methods applied to food‐safety risk assessment? What sensitivity analysis methods are most promising for application to food safety and risk assessment? and What are the key needs for implementation and demonstration of such methods? The workshop produced agreement regarding key criteria for sensitivity analysis methods and the need to use two or more methods to try to obtain robust insights. Recommendations were made regarding a guideline document to assist practitioners in selecting, applying, interpreting, and reporting the results of sensitivity analysis.     

Distinguishing traumatic, vicarious and routine operational stressor exposure and attendant adverse consequences in a sample of police officers

Problems in studying occupational stress within the police service are identified and the paucity of work on operational duties as potential stressors are discussed. The present study reports the results of a factor analysis of operational stressors (N = 601 serving British police officers) that revealed three factors: exposure to death and disaster; violence and injury; sexual crime. These were demonstrated to be reliable scales and were included in logistic regression models together with a range of demographic and psychological variables. Models were applied to men and women separately, which showed there to be different predictors of the likelihood of suffering distress (measured by the General Health Questionnaire, GHQ) in terms of the officer's gender and operational role. Overall the model for women officers was better at predicting psychological distress than that for men. These findings are related to aspects of the police occupational culture. Further discussion is offered that conceptualizes police operational stressors as traumatic, routine and vicarious. Finally, some implications are drawn for the provision of stress intervention in the light of this differentiation.     

Criteria for selecting a production control philosophy

Logistic objectives constitute a compromise between having short leadtimes and a low volume of work in progress on the one hand and a high resource loading and due date obligation on the other. Miscellaneous production planning approaches offered today provide different combinations of logistic objectives for satisfying a manufacturing strategy. To combine the strength of the various approaches into a unified system, a new approach based on a dynamic and distributed production planning methodology is proposed. To customize the approach, various analyses and specifications have to be made and for that reason some important characteristics and criteria for analysing production control philosophies will be given.     

The social construction of the meaning of acute stressors: a qualitative study of the personal accounts of police officers using a stress counselling service

The police profession is one in which acute stressors are encountered more frequently than in other occupations. Using the personal accounts of 35 police officers attending an in-house stress counselling clinic, the aim of the present study was to provide a qualitative examination of how the institutional context of policing influenced the ways in which acute stressors signified to individual police officers experiencing felt distress. Using the framework of Rational Emotive Behaviour Therapy as an analytical tool, it is argued that beliefs contributing to the experience of felt distress are related to the way in which policing as both an identity and an activity is constructed through the police organizational culture. Not only do these constructions influence the ways in which officers perceive themselves and their environments, but they also operate at the collective level to 'normalize' some emotional responses and to 'pathologize' others which, it is argued, could impact upon the outcomes of interventions such as stress counselling.     

The moderating role of social support in Karasek's job strain model

This paper examines whether social support is a boundary-determining criterion in the job strain model of Karasek (1979). The particular focus is the extent to which different sources of social support, work overload and task control influence job satisfaction, depersonalization and supervisor assessments of work performance. Hypotheses are tested using prospective survey data from 80 clerical staff in a university setting. Results revealed 3-way interactions among levels of support (supervisor, co-worker, non-work), perceived task control and work overload on levels of work performance and employee adjustment (self-report). After controlling for levels of negative affect in all analyses, there was evidence that high levels of supervisor support mitigated against the negative effects of high strain jobs on levels of job satisfaction and reduced reported levels of depersonalization. Moreover, high levels of non-work support and co-worker support also mitigated against the negative effects of high strain jobs on levels of work performance. The results are discussed in terms of the importance of social support networks both at, and beyond, the work context.     

Job insecurity, coping resources and personality dispositions in occupational strain

This paper presents research on the relationships between the work-related stressor of perceived job insecurity and various indicators of occupational strain, taking into account employees' personality dispositions (trait negative and positive affectivity) and coping resources. Respondents were 222 Australian public servants surveyed during organizational restructuring that involved downsizing and threat to job certainty. The research was formulated within an adaptation of Osipow, Doty, and Spokane's (1985) framework of stress-strain-coping that included the possible direct as well as moderating effects of personality dispositions in reporting occupational strain (Parkes, 1990). Findings from hierarchical regression analyses indicate consistent significant independent effects of personality dispositions, coping resources and perceived job insecurity on various indicators of strain. There was also support for the moderating roles of negative affectivity and self-care in the relation between perceived job insecurity and physical strain. Implications for the role of dispositional factors, especially negative affectivity, and the utility of various coping resources in accounting for occupational strain in times of threatened job security are discussed.     

Job stress, job strain, and psychological withdrawal among Dutch university staff: towards a dualprocess model for the effects of occupational stress

This study examined the antecedents of job strain (emotional exhaustion, health complaints) and withdrawal behaviour (e.g. lowered organizational commitment) among a cross-sectional sample of 131 academic staff members of the law department of a large Dutch university. Conservation of resources theory (Hobfoll, 1989) provided the theoretical background for this study. Strains and withdrawal behaviours were expected to be most prominent among those who reported having few resources and/or who reported high job demands. Structural equation modelling revealed that this was indeed the case. As predicted, differential patterns of effects emerged for job demands and job resources. Analysis of the effects of four job-specific stressors revealed that especially the structural aspects of a staff member's teaching task (e.g. the number of students in their classes) contributed strongly to perceived job demands. Theoretical and practical implications of the study are discussed.     

Employees' perceptions of organizational restructuring: the role of social support

Organizational change and restructuring is often perceived as leading to increased occupational stress, impacting negatively on the psychological well-being of employees. This pragmatic study investigates the role of social support and dispositional affect as moderators of role stress post-restructuring for employees in a public utility company. A total of 176 employees, including 37 managers, 60 graded staff and 78 industrial staff completed a self-report questionnaire, approximately 1 year postrestructuring, retrospectively assessing role conflict, ambiguity, overload and positive and negative feedback pre- and post-restructuring. Results suggested that overall role stress increased for managers/ senior officers and graded staff, but not for industrial staff. Social support was linked with lower role stress, more positive feedback and less negative feedback at post-restructuring. For certain role stressors this impact was moderated by dispositional affect, but the effect was not consistent across occupational groups. Positive affect enhanced the effect of manager support in reducing role conflict for graded staff, and the effect of co-worker support in increasing positive feedback and reducing negative feedback for industrial staff. Findings suggest that managers should pay particular attention to support and feedback for employees during periods of chronic occupational stress following organizational restructuring.     

The Danish psychosocial work environment and symptoms of stress: the main, mediating and moderating role of sense of coherence

The aim of this cross-sectional study was to explore the main, mediating and moderating role of sense of coherence (SOC) on stress symptoms and on the association between perceived psychosocial work environment and stress symptoms. The sample includes 2053 Danish employees from 52 workplaces. Hierarchical regression models were applied for each measure of stress. The results strongly supported the presence of a main effect for SOC. People with high levels of SOC experienced fewer stress symptoms. A mediating effect of SOC was also supported. Thus, SOC in part explained the association between work environment and stress symptoms. In addition, some support for a moderating effect of SOC was found, suggesting that people with higher SOC coped more efficiently with work environmental strain that people with lower SOC. Taken together the regression models explained 11-32% of the variance in stress symptoms. The results suggest that measures of individual factors such as SOC should be included in analyses of the effects of work environmental factors on stress and well-being.     

Control at work: a generalized resource factor for the prevention of musculoskeletal symptoms?

During the last two decades two potent groups of predictors for work-related musculoskeletal problems have been identified: physical work load and poor psychosocial working conditions. However, little is known about their combined effects. In this study the buffering effect of control at work with respect to the negative effects of psychological demands and physical work load on musculoskeletal problems is examined. All study variables were sampled from 431 people working in geriatric nursing homes in Germany by means of questionnaires. Main effects and interactions were tested with multiple regression analysis. The results showed that control buffered the effects of high psychological demands, but not of high physical work load; the buffering effect of control was observed only when physical work load was low. The combined effects of demands and physical work load were over-additive. Thus, the power of different predictors for musculoskeletal symptoms depended on the level of other predictors. This suggests that the efficiency of certain strategies for the prevention of musculoskeletal problems is likely to depend on the level of risk factors, with different strategies being appropriate for different levels of risk.