基于不确定条件下的供应商参与协同设计决策分析

以供应商参与协同设计所承担任务比例,作为其参与程度的定量指标,考虑研发不确定性,从供应商角度出发寻求其最适合的参与程度。研究结果表明,对于供应商而言,其参与受双方相对边际利润和开发能力,以及新产品市场不确定性的限制。供应商参与分担制造商部分设计任务有一个最适当的比例,该比例与其自身边际利润及技术开发能力正相关,与制造商边际利润以及技术开发能力负相关,与产品市场成功概率负相关。     

外包环境下考虑产品质量的OEM采购战略决策

产品质量是业务外包中的关键问题,同时也是决定企业采购战略选择的重要变量。研究了生产两种替代性产品的制造商的采购战略选择问题,并讨论了不同采购战略对于供应商产品质量决策的影响。考虑制造商可以选择单源策略或者双源策略,并讨论了在四种情形下供应商和制造商的战略互动: 单源策略下,制造商可以选择分享供应商的质量投资或不分享供应商的质量投资; 双源策略下,两个供应商可以选择合作质量决策或者竞争质量决策。研究发现,一个合适的质量投资分享比例能使得与单个供应商合作战略成为制造商的占优选择; 如果制造商不愿意分享或者不愿意分享足够多的质量投资,当双源采购成本足够小时,开发两个竞争性供应商成为制造商的占优策略。对于双源采购策略,还讨论了制造商分享两个供应商质量投资的采购战略,并验证了当分享比例和双源采购成本足够小时,该战略成为制造商的唯一占优选择。另外,当制造商选择双源采购战略时,应避免供应商合作质量决策,因为供应商的质量合谋将会通过提供劣质产品而抽取更多的制造商利润。     

基于决策优先权的闭环供应链运作效益研究

针对由一个制造商和两个零售商组成由制造商直接回收旧品的闭环供应链系统,利用博弈论方法,研究了零售商决策权均衡的"E"情形和其中一个零售商具有决策优先权的"A"情形对于运作效益的影响.通过结果比较分析,可知"A"情形相对于"E"情形,制造商的边际利润增大而最优利润均下降,但两个零售商的边际利润和最优利润均有所增加.所以"A"情形中,制造商的最优利润降低,主要是由于回收努力系数的降低所致,但边际利润增加了,同时,回收努力系数较小,所以对于刚刚涉足产品回收和再制造的制造商来说,"A"情形不失为一种较好的选择;但"E"情形是制造商积累了闭环供应链管理经验后的终极选择.     

共性技术VS专用性技术:基于三阶段非合作博弈的供应商研发决策

本文针对面向多制造商的供应商研发决策问题,分别构造了供应商在选择共性技术和专用性技术研发决策情形下与两个制造商组成的三阶段非合作博弈模型,得到了供应商在这两种情形下各自的最优研发决策,通过对这两种最优决策情形下供应商最优研发程度比较,给出了这两种情形下供应商研发程度相等的条件和各自的占优区间。论文进一步讨论了供应商单位成本、制造商单位成本、最终产品替代率、单位研发成本变动对这两种情形下供应商最优研发决策的影响,并给出了相应的数值解,表明采用不同技术研发决策时供应商最优研发程度与制造商单位成本存在显著差异,即:采用共技术性研发决策时,与两个制造商单位成本负相关;采用专用性技术研发决策时,与面向专用性的制造商单位成本正相关,无专用性面向的制造商单位成本负相关。     

不确定交货条件下两供应商-单制造商协同供货模型

研究了不确定交货条件下两供应商-单制造商系统基于惩罚策略的协同供货模型。首先建立了基于惩罚策略的供应商和制造商模型,接着对模型中供应商和制造商的最优决策进行了分析,得出两供应商的最优生产批量决策存在唯一纳什均衡,且最优期望利润间接地受其单位缺货成本的影响,而制造商最优订货批量大于等于市场需求。其次建立了集中决策下供应链利润函数模型,并证明了该函数是决策变量的联合凹函数,存在唯一的最优解。为了达到集中决策下的供应链利润最大化,推导出基于惩罚策略的供应链协同机制。制造商通过调整订货批量和零件单位缺货惩罚成本,在供应链利润最大化前提下获得最大的剩余利润。最后数例分析说明制造商如何通过控制该惩罚成本系数使得供应链协同并获得最大的剩余利润。     

考虑消费者低碳偏好的供应链减排微分博弈模型研究

针对由一个供应商和一个制造商构成的两级供应链,考虑消费者的低碳偏好和碳交易政策,建立分散决策和集中决策两种情形下的微分博弈模型解决供应链动态优化问题,比较两种情形下的最优均衡反馈策略、减排量的最优轨迹及最优利润,提出减排策略。通过数值仿真,进一步验证了命题的有效性;通过对消费者低碳偏好及碳交易价格进行灵敏度分析发现：随着低碳偏好的增加,供应商和制造商的减排量和供应链系统的利润均增加,并且政府在规划期内应及时调整碳交易政策,达到激励企业减排的效果。     

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.     

政府补贴方式对绿色供应链制造商减排决策的影响机制

考虑制造商自主研发减排与外包减排任务两种情形,研究政府分别依据减排研发和单位产品减排量进行补贴下供应链的最优决策问题。从供应链制造商的角度,对给定政府补贴方式下,制造商的两种减排决策进行了对比,同时从政府的角度,在制造商特定的减排情形下,两种政府补贴方式的减排效果进行比较。进一步,通过数值仿真分析两种补贴方式下补贴系数对供应链决策的影响。研究结果表明,当政府采取依据减排研发的补贴方式进行补贴时,自主研发减排情形下制造商利润大于外包减排任务情形的利润;当政府采取依据单位产品减排量的补贴方式时,相比外包减排任务,制造商选择自主研发减排均能得到更多的减排量和利润。当制造商自主研发减排时,政府依据减排研发补贴方式比单位产品减排量补贴方式的减排效果更好,但利润较低;当制造商外包减排任务时,两种政府补贴方式的减排效果和利润均相等。通过数值仿真验证了以上结果,同时表明补贴系数对减排效果和利润具有显著影响。以上结论为政府制定合理的补贴方式及企业减排策略的选择提供了理论支撑。     

需求不确定条件下的制造商订单分配模型

制造商的订单分配作为供应链模型微观层面的重要组成部分,对提升整个供应链效率有很大影响,但需求层面的不确定因素加大了订单分配的难度。以按比例分配为原则,讨论在需求不确定条件下完全信息与不完全信息两类多供应商-单制造商的订单分配模型。重点研究完全信息条件下各方的分散决策和集中决策,由于后者能避免各参与方对其他决策方的边际影响,所以能够实现供应链总利润的最大化;其次又将不完全信息引入模型,讨论制造商如何通过折算因子结合已有信息对供应商的私人信息进行估计,进而做出决策。最后以需求服从正态分布为例对两类模型进行验证。     

基于产品责任的零售商主导供应链质量成本分担合同研究

基于以零售商为主导的两级供应链，在供应商产品质量缺陷对消费者造成效用损失，并导致零售商承担产品责任的情形下，考虑了如何设计质量成本分担合同以激励产品质量水平的提升。基于此，考虑了两种质量成本分担比例(合同)决策模式(即零售商决策和纳什讨价还价决策),构建了供应链动态博弈模型，考察了责任成本对供应链质量决策和企业利润的影响机理，并揭示了不同质量成本分担比例决策模式对供应链均衡结果差异的策略性机理。结果表明：(1)在分散化下，当供应商质量投资效率较高(较低)时，其产品质量随责任成本的增加而增加(减小);而在质量成本分担合同下，随着责任成本的增加，最优质量成本分担比例随之增加，而产品质量随之先提高后降低。(2)质量成本分担有助于产品质量、零售商利润和供应链系统利润的提高，而供应商利润在纳什讨价还价决策模式下将提高，但在零售商决策模式下，当责任成本较小时其反而将降低。(3)相对于零售商决策模式而言，在纳什讨价还价决策模式下，最优质量成本分担比例、产品质量和零售商利润均相对较低，但供应商利润和供应链系统利润均相对较高。     

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.     

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.     

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.     

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.