基于合作博弈的易腐性产品运输设施选择的费用分配

易腐性产品的价值会随着时间而损失,运输易腐性产品时,客户除了支付运输费用外还需要承担产品的价值损失。本文把易腐性产品的价值损失和运输费用之和作为总费用,应用合作博弈理论,把易腐性产品的运输设施选择的费用分配问题构造成费用分配博弈,证明了在易腐性产品线性价值损失的情况下,运输设施选择博弈的核心非空,且为子模博弈,并讨论核仁、夏普利值、τ-值等解。论文最后讨论了有约束运输的设施选择的费用分配博弈的解的情况,说明其核心也许为空,并提出了进一步研究的方向。     

易腐性产品运输设施选择博弈

易腐性产品的价值会随着时间的流逝而逐渐损失,多个客户可以联合使用某种运输设施时,如何对费用进行公平且稳定的分摊是合作能否进行的基础.把易腐性产品的损失价值和运输费用之和作为总费用,进而将易腐性产品的运输设施选择的费用分配问题构造成运输设施选择合作博弈,证明了在易腐性产品负指数价值损失的情况下,运输设施选择博弈的核心非空,且为凹博弈,并讨论了解的特征.论文还证明具有附加运输费用的运输设施选择博弈的核心非空,分析了核心与线性规划松弛的对偶最优解之间的关系.论文对有约束设施选择博弈进行了分析,并提出了进一步研究的方向.     

考虑质量与数量损耗控制的生鲜农产品保鲜策略研究

生鲜农产品具有质量和数量双重损耗特性，零售商需采取合理的保鲜控制策略降低损耗带来的损失。对此，建立了同时控制生鲜农产品质量和数量损耗、显著控制数量损耗和显著控制质量损耗三种保鲜策略下，考虑质量损耗和数量损耗的生鲜农产品库存模型和零售商利润模型，对比分析了零售商的最优保鲜策略选择以及对应的订货和定价策略。研究发现：当质量损耗和数量损耗控制效果一定时，随着价格和新鲜度敏感系数之比或批发价格逐渐增大，零售商的保鲜策略选择由显著控制数量损耗转变为双重损耗控制，进而转变为质量损耗控制。而当保鲜成本和保鲜效果敏感系数较低时，零售商只会在两种具有单一损耗控制效果的保鲜策略中进行选择；但当保鲜成本和保鲜效果敏感系数增大时，零售商选择双重损耗控制保鲜策略的可能性越大。     

基于产品新鲜度要求的保鲜成本投资与数量集配策略联合决策研究

文章以提供生鲜产品运输配送服务的物流企业为研究对象,考虑生鲜产品质量腐蚀特性,应用随机更新理论建立基于下游零售商产品新鲜度水平要求的保鲜投资与物流集配联合决策随机模型。模型分析指出单位时间的运输成本、集配惩罚成本与保鲜投入成本随保鲜投资决策与物流集配决策变化的内在规律。数值分析指出保鲜投资、物流集配及其联合决策的有效性和产品、成本、需求环境等参数与这些环境参数同时变化对保鲜投资决策、集配决策与企业运营成本的影响。     

改良技术共享下改良品联合采购联盟的竞合博弈研究

改良技术共享与联合采购在一定程度上能够降低改良品采购联盟的运作成本。但是，是否选择进行改良技术创新，改良率提高到什么程度，是否进行改良技术共享，形成改良技术共享与联合采购联盟之后如何进行运作成本分摊可以保持其稳定性，是零售商进行改良技术共享后改良品联合采购联盟所需要解决的关键问题。本文基于经典的EOQ模型，建立了改良技术共享下改良品联合采购联盟成员间既有竞争又有合作的竞合博弈模型。首先，当零售商各自进行改良技术创新并在联盟内共享改良技术时，确定了改良技术共享下改良品联合采购联盟的运作策略与总成本；随后，给出了一种分配方案证明改良技术共享下改良品联合采购合作博弈的核是非空的；最后，指出平均分配方案所得到的改良率将低于集中化决策时零售商的最优改良率，并指出在该合作博弈核的极点的成本分摊规则下，此联合采购联盟的总成本是最低的。本文的研究表明，采用平均分摊成本的方案将不能达到系统最优，而采用核的极点的成本分摊方案将可以使成本降低至系统集中化决策时的水平。     

考虑消费者效用的生鲜农产品供应链保鲜激励机制研究

针对消费者对生鲜农产品新鲜度要求较高但供应商独自保鲜动力不足的问题,在构建消费者时变效用函数的基础上建立了由零售商和供应商组成的两级生鲜农产品供应链利润模型,设计了“基于生鲜农产品新鲜度的采购价”契约和“批发价+保鲜成本分担”契约两种促进供应商提高保鲜努力的激励机制.研究发现,两种激励机制均能提高供应商保鲜努力水平,并且在一定程度上实现供应链协调.当零售商具有强势地位时,其在“基于生鲜农产品新鲜度的采购价”契约下比“批发价+保鲜成本分担”契约下能够获得更高的利润.最后通过数值算例分析了不同消费者偏好对供应链最优决策的影响.     

具公平行为的零售商回收闭环供应链动态均衡策略研究

本文研究了一主导制造商（再制造商）和一"嫉妒/自豪"公平关切行为的零售商（回收商）组成的闭环供应链系统的成员动态均衡策略。利用伊藤过程，刻画了闭环供应链系统的废旧品回收率的随机演化过程。基于利润结构，给出了制造商的期望利润目标泛函。基于零售商的"嫉妒/自豪"型模式，构建了零售商的期望效用目标泛函，进而建立了闭环供应链系统的随机微分博弈模型。利用随机微分博弈理论，给出了制造商和零售商最优值函数应满足的偏微分方程组。通过求解该偏微分方程组，获得了制造商和零售商最优值函数，据此得到了制造商的动态均衡批发价格策略以及零售商的动态均衡销售价格与回收投入努力策略。为了掌握废旧品回收率的统计特征，揭示了废旧品回收率的随机演进性质。结合算例，研究了零售商公平关切程度对成员均衡策略以及绩效的影响。结果表明：零售商公平关切程度越高，制造商的均衡批发价格越低，进而导致其最优值函数将减少。与制造商不同，零售商公平关切程度将增加其最优值函数。另外，零售商公平关切程度越高，系统回收率越低。     

基于消费者效用的生鲜农产品供应链生鲜度激励机制研究

生鲜供应链整体生鲜度的提升对减少浪费、提高供应链整体盈利水平及社会福利有重要意义。本文基于消费者效用理论研究了两供应商和单一零售商组成的供应链系统，构建了单周期下生鲜农产品生鲜度激励模型，模型以供应商为领导者，采用Stackelberg博弈方法求解得到了均衡状态下供应商、零售商的最优定价策略及供应商新鲜度努力选择。研究结果表明，供应商和零售商利润与消费者价格敏感系数呈反向变化，与新鲜度敏感系数呈同向变化。在价格竞争市场，供应商保鲜努力程度和利润与价格替代率呈反向变化；在生鲜度竞争市场，供应商保鲜努力程度和利润与新鲜度替代率呈同向变化。基于研究结论，厂商及政府应当联手引导消费者的消费观念，尽可能减少由于信息不对称引致的道德风险，在市场价格替代率不变甚至降低的情形下，提高生鲜度替代率，使得消费者的意愿支付价格上升，提高自身讨价还价能力，获取更多利润。     

考虑权力结构及供应商竞争的生鲜供应链决策

考虑消费者新鲜度偏好,研究了两竞争性供应商和单零售商组成的生鲜农产品供应链决策问题.针对供应链的3种权力结构：供应商领导(SS)、无领导(VN)和零售商领导(RS),构建生鲜农产品供应链的两阶段博弈模型.结果表明：1)SS情形下,当两竞争性供应商的产品品质差异值高于临界值时,零售商会向低品质供应商订货;否则,零售商会向高品质供应商订货;2)VN情形下,生鲜农产品品质提升导致批发价格上升,但不一定伴随着销售价格的上升,且产品品质提高导致批发价格上升的阈值大于产品品质导致销售价格上升的阈值;两供应商之间的竞争越激烈,均衡时的批发价也就越低,但零售商边际利润越高;3)RS情形下,供应商提供的生鲜农产品新鲜度越高,零售商获取的该生鲜农产品边际利润也就越高,但竞争供应商边际利润不变.4)3种情形下,当生鲜农产品的品质较低且低于临界值时,VN情形时供应商利润最低,SS情形下供应商获得的利润高于RS情形.     

基于Stackelberg博弈的变质物品分销网络设计模型

研究了一类短销售期的变质物品的分销网络设计问题.假定零售商的缺货成本依赖于分配给为其提供服务的分销中心的库存成本,供应商在销售期末给零售商提供第二次订货机会,供应商根据零售商的订货决策确定分销中心的最优选址和确定每个分销中心为哪些零售商提供服务,从而最小化总的运作成本(选址成本,运输成本,库存成本和变质成本),其中分销中心的运输成本和库存成本依赖于零售商确定的订货数量;而零售商则根据供应商的决策确定自身的最优订货决策,利用Stackelberg博弈分析的方法,建立了一类变质物品的分销网络设计模型,并使用拉格朗日松弛算法求解,最后通过数值算例分析了模型最优解对于参数的敏感性.     

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.     

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.     

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.     

Dermal Uptake of 18 Dilute Aqueous Chemicals: In Vivo Disappearance‐Method Measures Greatly Exceed In Vitro‐Based Predictions

Average rates of total dermal uptake (K_up) from short‐term (e.g., bathing) contact with dilute aqueous organic chemicals (DAOCs) are typically estimated from steady‐state in vitro diffusion‐cell measures of chemical permeability (K_p) through skin into receptor solution. Widely used (“PCR‐vitro”) methods estimate K_up by applying diffusion theory to increase K_p predictions made by a physico‐chemical regression (PCR) model that was fit to a large set of K_p measures. Here, K_up predictions for 18 DAOCs made by three PCR‐vitro models (EPA, NIOSH, and MH) were compared to previous in vivo measures obtained by methods unlikely to underestimate K_up. A new PCR model fit to all 18 measures is accurate to within approximately threefold (r = 0.91, p < 10^?5), but the PCR‐vitro predictions (r > 0.63) all tend to underestimate the K_up measures by mean factors (UF, and p value for testing UF = 1) of 10 (EPA, p < 10^?6), 11 (NIOSH, p < 10^?8), and 6.2 (MH, p = 0.018). For all three PCR‐vitro models, log(UF) correlates negatively with molecular weight (r² = 0.31 to 0.84, p = 0.017 to < 10^?6) but not with log(vapor pressure) as an additional predictor (p > 0.05), so vapor pressure appears not to explain the significant in vivo/PCR‐vitro discrepancy. Until this discrepancy is explained, careful in vivo measures of K_up should be obtained for more chemicals, the expanded in vivo database should be compared to in vitro‐based predictions, and in vivo data should be considered in assessing aqueous dermal exposure and its uncertainty.     

Systems Resilience for Multihazard Environments: Definition,Metrics, and Valuation for Decision Making

The United Nations Office for Disaster Risk Reduction reported that the 2011 natural disasters, including the earthquake and tsunami that struck Japan, resulted in $366 billion in direct damages and 29,782 fatalities worldwide. Storms and floods accounted for up to 70% of the 302 natural disasters worldwide in 2011, with earthquakes producing the greatest number of fatalities. Average annual losses in the United States amount to about $55 billion. Enhancing community and system resilience could lead to massive savings through risk reduction and expeditious recovery. The rational management of such reduction and recovery is facilitated by an appropriate definition of resilience and associated metrics. In this article, a resilience definition is provided that meets a set of requirements with clear relationships to the metrics of the relevant abstract notions of reliability and risk. Those metrics also meet logically consistent requirements drawn from measure theory, and provide a sound basis for the development of effective decision‐making tools for multihazard environments. Improving the resiliency of a system to meet target levels requires the examination of system enhancement alternatives in economic terms, within a decision‐making framework. Relevant decision analysis methods would typically require the examination of resilience based on its valuation by society at large. The article provides methods for valuation and benefit‐cost analysis based on concepts from risk analysis and management.     

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.     

UNIX系统性能监控简述及shell系统资源统计程序

本文简要阐述了unix系统中(主要以IBM的AIX为例)进行系统性能管理的几种命令行工具,并通过编写shell实例程序,运用其中提到的工具实现系统资源利用率的统计程序,为做好unix系统管理和调优提供参考.