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。     

供应链收入共享契约协调的随机期望值模型

本文研究了供应链契约协调中的收入共享契约.建立了具有缺货成本的供应链收入共享契约协调的随机期望值模型,推导了实现分散供应链协调的收入共享契约参数之间的关系,分析了收入共享机制在改进供应链整体运作绩效方面的作用.设计了求解随机期望值模型的混合智能算法,进行了收入共享契约协调模型仿真实验,探讨了收入共享契约参数变化对供应链成员绩效的影响.结果表明,本文建立的收入共享契约协调的随机期望值模型具有实际意义,并在随机需求条件下协调了供应链运作.     

考虑顾客行为与零售商公平关切的易逝品定价与供应链协调研究

本文在公平中性的供应商、公平关切的零售商和策略型与短视型顾客并存的供应链下,研究了零售商的最优定价与订货量及供应链的协调.研究发现,公平关切的零售商有提高产品价格和压低订货量的倾向;批发价契约难以实现供应链的协调;收益共享契约能实现供应链的完美协调.论文还讨论了零售商的公平关切程度和利润分享比例对供应商利润、零售商效用及供应链效用的影响.     

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.     

考虑损失厌恶一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 － 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．     

不确定性环境下不同补货策略的供应链契约协调研究

针对产出和需求不确定性导致的残值或补货问题,考虑单个制造商和零售商所组成的双边随机供应链,双方采取事前订单形式,构建两种不同现货市场补货策略模型,研究随机环境下最优原材料投入量-成品订货量决策行为及供应链协调。研究表明：零售商自行补货时,收益共享合同不能分担上游产出不确定性风险,制造商为避免产出过剩会减小投入量导致合同失效,但融合了缺货惩罚-余货补偿双向机制的收益共享契约能够进行有效协调。当由制造商补货时,现货市场降低了产出不确定性风险且提高了系统产出投入比,并能重新使收益共享契约生效。此外,有效契约协调后的各方收益均为系统最优收益的仿射函数,并由协商后的收益共享比例控制着分配系数。理论分析和数值仿真说明了合同协调的有效性。算例分析还发现,设计的收益共享风险共担契约相比单一的收益共享契约能够更好地降低不确定性对收益的影响。     

零售商的资金约束对协调契约的影响分析

在零售商促销下,探讨了零售商的资金约束对使用收益共享契约和回购契约协调供应链的影响。分析了零售商拥有不同运营资金下供应链的契约协调问题,研究表明：在运营资金相对充裕下,收益共享契约不仅能协调供应链,且能实现渠道收益的任意分配,但回购契约不能实现渠道收益的任意分配,除非运营资金非常充裕;在运营资金不足下,收益共享契约仍有可能协调供应链,但回购契约不能协调供应链。讨论了资金的时间价值对两个契约协调供应链的影响,结果表明：在回购契约下,资金利率越大,具有资金约束零售商的供应链被协调的可能性越大,但资金利率对收益共享契约没有影响。最后提供了数值分析。研究中得到一些管理启示,可为资金约束供应链的协调管理提供理论借鉴。     

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。     

两阶段价格和需求变动产品的供应链协调

通过建立两阶段动态模型研究了价格和需求变动产品的供应链协调问题。首先建立了集中协调、分散无协调和分散收入共享协调三种模式下供应链的动态规划模型;证明价格和需求变动时供应链在不同模式下存在最优解,应用改进的收入共享契约可以协调供应链系统并取得集中协调供应链系统的绩效,并可实现供应链利润的任意分配;给出了协调契约参数的确定方法;讨论了价格、市场需求风险变化对供应链协调绩效及最优契约参数的影响;通过数值实验分析证明了改进的收入共享契约可以使系统各方共同承担风险及分享利润,使各方绩效达到Pareto最优。     

基于双重努力因素的供应链销量担保期权模型

对于一个单期两级简单供应链,引入供应商的生产努力因素,并在需求随机并与供应商和销售商的努力水平相关的条件下,研究供应链节点企业的努力投入与供应链激励问题.为此,论文首先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,分析了在该契约下供应商的生产努力和销售商的销售努力对供应链决策的影响.研究发现,在考虑努力因素时,由于努力投入的外部性,单纯的期权销量担保模型缺乏对节点企业努力行为的激励,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,对原契约进行修正,当收益共享比例、努力成本共担比例满足一定条件时,修正契约可以实现供应链协调.最后,对论文的研究结论进行了拓展,并通过算例分析说明了研究结论的有效性.     

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.