考虑努力水平和决策风险偏好的供应链期权销量担保模型

对销售商和供应商组成的简单两级供应链,在供应链参与企业的风险偏好影响其决策选择,以及在需求随机并受销售商营销努力水平影响的市场环境下,建立了基于销量担保期权的供应链契约模型。提供了一种基于期望损失的期权定价方法,分析了努力水平和决策风险偏好双重因素对参与企业的决策及其供应链协调的影响。研究表明在考虑努力水平和决策风险偏好差异时,单纯的期权销量契约无法实现供应链协调。为此,引入收益共享和努力成本共担策略,对原契约模型加以修正。在修正契约中,当收益共享比例和努力成本共担比例满足一定条件时,修正的期权销量担保契约可以实现供应链协调。最后,提供了一种模型优化分析方法,并通过案例分析说明了研究结论的有效性。     

基于收益共享与努力成本共担的供应链期权销量担保契约

对销售商和供应商组成的两级供应链,在需求为随机且与努力水平相关的市场环境下,建立了供应链期权销量担保契约模型,提供了一种基于期望损失的期权定价方法,分析了努力因素对供应链协调的影响。研究得出在考虑努力因素时单纯的期权销量契约无法实现供应链协调,为此,引入收益共享和努力成本共担策略,对原契约加以修正,当收益共享和努力成本共担比例满足一定条件时,则可以实现供应链协调,并进一步讨论了使修正契约具有帕累托优势的条件。最后,提供了一种模型优化分析方法,并通过算例分析验证了研究结论的有效性。     

考虑决策风险偏好的期权销量担保模型

针对供应链合作的新模式,构建基于担保销量的单期两级供应链期权契约模型,并将决策者风险偏好引入决策模型,利用Pratt-Arrow绝对风险厌恶度对合作中所转移的风险成本进行了刻画,以此修正供应商和销售商的决策效用函数。研究得出了供应商购买的最优担保销量以及最优生产批量,并分析了最优担保销量存在的条件和销售商的最优风险溢价系数所满足的条件。论证了考虑决策风险偏好的期权销量担保契约在产品的生产批量安排上能够实现供应链协调。最后通过案例验证了本文的研究结论。     

考虑努力因素的供应链收益共享演化契约

在需求随机、努力水平影响需求的供应链环境里,在传统供应链收益共享契约基础上构建了一种演化契约.并在委托代理框架下,对该演化契约进行了研究.首先分析了销售商的努力因素对收益共享契约的影响,得出了销售商努力水平反应函数及最优投入值;其次,研究得出了供应商在收益共享契约中,向销售商所提供的最优收益共享比例,以及最优的分担销售商的努力成本比例;再次,论证了本文所研究的收益共享演化契约可以实现供应链协调;最后,通过算例分析验证本文研究结论的有效性.     

基于期权的销售量担保模型

针对需求不确定性大、生产提前期长、销售季节短的这类产品的合作问题,构建了基于担保销售量的单期两级供应链期权契约模型.在这种机制下,销售商出售基于担保销售量的期权.供应商通过向销售商购买期权可将部分风险转移给销售商,而销售商也因出售期权获得相应的风险补偿,这种契约安排能够实现供应链的协调.而且如果供应商向销售商提供一定的转移支付,这种契约安排能够激励销售商加大营销宣传的投入,改善产品的市场需求状况.从而提高整个供应链的绩效.     

节点企业地位相当时供应链双向激励及协调

在节点企业地位相当的二级供应链中,销售商隐藏努力行动、供应商隐藏成本信息,从而导致供应链效率低下。为此,运用委托代理理论,引入虚拟第三方为协调主体,从供应链整体利益最大化出发,对供应链进行集中控制、利润分配,对供应商和销售商实施双向激励。结果表明,与供应商主导供应链时的情形相比,当销售利润共享比例α*和成本共担比例β*满足更为苛刻的关系时,供应链才能实现协调。但是,此时的虚拟第三方承认了供应商的信息租金,其决策的角度是供应链期望利润的α*倍。最后,通过一个算例对研究结果进行了说明。     

基于双向期权的供应链柔性契约模型

对需求不确定性大、生产提前期长、销售季节短的产品的供应链合作问题,建立了基于双向期权的单期两级供应链数量柔性契约模型,研究得出了销售商最优初始订货量和期权购买量,而且与单向看涨期权契约相比,销售商的期权购买量减小,初始订货量增加,但总的预期订货量减小.供应商的最优产量需综合考虑产品的正常生产模式和快速生产模式的成本,以及销售商执行期权的预期.供应商的生产不确定受销售商执行期权的相关性影响,降低相关性可以降低生产风险.双向期权契约能够提高销售商的采购柔性、降低市场风险,但也减少了部分收益.供应商增加了部分风险,同时也获得收益补偿.最后.通过数值算例分析了论文中的研究结论.     

盟员行为偏好下生鲜农产品供应链生鲜努力激励机制与协调研究

本文建立了"合作社+核心企业"模式下两阶段折扣定价的二级生鲜农产品供应链，基于消费者生鲜偏好、价格敏感度对市场需求的影响，选取Nash谈判解作为公平参考点，引入合作社公平偏好理论，研究供应链盟员保鲜投入决策。针对合作社保鲜努力激励，探讨供应链盟员偏好对保鲜努力水平以及收益共享契约激励协调效果的影响。研究发现，消费者生鲜偏好的提高能够促进收益共享契约的激励效果，并且提高合作社公平效用。同时，收益共享契约在第一阶段对保鲜努力水平的激励效果优于第二阶段，而在第二阶段联合使用收益共享和成本分摊能够显著提高该阶段的保鲜投入。     

不同权力结构下供应链企业社会责任激励

本文以单个供应商和单个零售商组成的两级供应链为对象,假设仅考虑供应商对产品安全方面的社会责任,研究了在供应商主导和零售商主导两种权力配置模式下,供应商履行社会责任程度的差异,以及如何在供应商和零售商间建立合理的契约以激励供应商社会责任的履行。研究发现,相对供应商主导,在零售商主导下供应商会更多地履行社会责任。引入收入共享的事后契约和成本共担的事前契约后,在供应商主导下,两种契约在一定条件下均能有效地激励供应商更好地履行社会责任,但在留存比例与分担比例相等的条件下,成本共担契约的激励效应更强。在零售商主导下,收入共享契约虽能激励供应商的社会责任履行,但因导致零售商的利润下降,故无法达成,而成本共担契约只有在分担足够大时才有激励效应。     

考虑零售商风险规避的生鲜供应链区块链技术投资决策及协调

鲜活度信息具有供应商私有性,实际供应链中可能存在谎报现象,投资区块链技术可以抑制供应商的谎报行为。本文分析该技术投入前后供应链均衡解的变化,寻求不同情形下区块链技术成本投资阈值,并设计收入共享契约、回购补偿契约进行供应链协调,提出非对称纳什均衡谈判来分配盈余收益。研究表明:合作博弈下,区块链的成本投资阈值、供应链系统收益大小取决于单位产品区块链技术投入成本、交易缩短后的时间及单位产品交易节约成本,与供应链成员的风险规避度无关;三种Stackelberg博弈都存在一个技术投资临界值,且供应商和零售商所能接受的投资阈值不同,是否投资区块链取决于供应商,信息共享度越高越倾向于投资,且投资成本分担比例只影响批发价格。收入共享契约、回购补偿契约协调均使供应链成员收益达到双赢效果,通过非对称纳什均衡谈判能够实现契约协调后动态盈余收益的分配。最后,本研究给出算例分析验证了相关结论。     

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.     

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.     

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.