竞合供应链的采购与质量决策研究

研究由原始设备制造商、竞争供应商与非竞争供应商构成的竞合供应链中原始设备制造商的采购决策,并分析了品牌效应、竞争供应商的模仿能力、非竞争供应商的原材料供应能力对采购模式选择与质量决策的影响。结果表明,双源采购对原始设备制造商而言是最优的采购策略;竞争供应商模仿能力较小时,原始设备制造商决策的产品质量随竞争供应商模仿能力的增大而提高,而当竞争供应商的模仿能力较大时,其模仿能力的增强会导致原始设备制造商降低产品的质量;原始设备制造商的品牌效应可以降低竞争供应商的竞争程度;非竞争供应商提高原材料供应能力并不一定能为自己带来更高的利润。本文考虑品牌效应和竞争供应商模仿能力等对原始设备制造商质量和采购决策的影响,扩展了现有的研究。     

制造商对供方缺陷改善投资的双源采购决策研究

研究在供需均随机的情况下，面对供应原料存在质量差异的两个供应商，制造商考虑对供方进行缺陷改善投资的双源采购决策问题． 构建了制造商将高质量( 缺陷率低) 供应商作为缺陷改善低质量( 缺陷率高) 供应商的标杆，以求两供应商质量一致的双源采购决策模型． 获得了制造商在先改善投资后订货与同时改善投资和订货两种策略下最优订货量，供应商最优生产量与他们的最优利润． 分析了改善投资成功率对制造商订货量与利润的影响． 研究发现:当改善投资成功率小于1 时，先改善投资再订货时制造商利润比同时改善投资和订货时高; 而改善投资成功率为1 时，两种订货策略没有差异．     

基于质量意识的复杂产品质量控制激励策略

激励在复杂产品供应链中对主供协同合作关系及质量控制发挥了重要作用。本文研究基于主制造商在复杂产品生产研发前按照客户要求形成的质量意识的激励策略是否可以实现复杂产品质量控制问题。考虑具有质量意识的主制造商和其系统供应商组成的两级供应链,建立以主制造商为领导者的Stackelberg博弈模型,分别讨论无激励和存在激励时的主供生产最优决策。基于激励方式的不同,将激励策略分为根据供应商产品质量水平激励以及根据主制造商质量意识水平激励两种方式。研究结果表明激励是供应商加强协同合作、改进产品质量的内在动力,主制造商根据质量意识激励供应商可以进一步促使双方协同合作,提高产品质量,使双方获得更高的利润从而实现供应链整体利润最大化。此外用灵敏度分析发现提高主制造商质量意识水平可以增加双方协同合作努力程度,有效提升产品质量水平并实现帕累托改进。     

存在信息更新时的双源采购和后备生产结合策略研究

在现实的采购运作中，双源采购和后备生产是两种最常见的风险应对策略。本文在考虑信息更新的情况下，探讨了一个两阶段动态采购决策模型：第一阶段，制造商向存在供应风险的一个或两个主供应商订货；第二阶段，制造商根据主供应商风险信息的更新，决定是否向供应可靠但价格较高的后备供应商订货。本文得到了两阶段的最优采购策略，分析发现，当固定采购成本较低时：若潜在市场需求较小，双源采购将排斥后备生产；若潜在市场需求较大，双源采购和后备生产共存；若潜在市场需求适中，后备生产可能排斥双源采购，两者也可能共存。特别地，在潜在市场需求适中时，可靠性改进概率的增大或后备供应商生产成本的降低，将使后备生产趋于排斥双源采购；反之，可靠性改进概率的减小、固定采购成本的降低或后备生产成本的增加，将使两者趋于共存。     

产品定价及质量投资决策序列对两级装配系统的影响研究

为研究供应链结构对供应链绩效的影响,构建了两级装配系统中质量投资与价格决策模型。分析了3种不同决策序列的纳什均衡,并从各参与方的角度讨论了其最优决策序列,即供应商先同时进行质量决策后再同时进行批发价格决策、供应商同时进行质量决策和批发价格决策以及供应商1先进行质量和批发价格决策。研究发现,集中决策优于独立决策,且价格敏感系数越低、质量敏感系数越高集中决策的优势越显著;第1种决策序列下供应链总利润最高;第2种决策序列是制造商的占优策略,但是供应商1的最差策略;第3种决策序列下供应商2的利润最低。     

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。     

供应链中具有产能限制的竞争企业中的信息共享研究

本文研究由一个供货商和两个制造商组成的二级供应链中，制造商之间的横向信息共享策略和供应商的定价问题。在模型中，上游供应商同时为下游两家制造商提供价格相同的原材料，下游制造商生产具有替代性的商品进行数量竞争，并受到相同的产能限制。以Cournot博弈为研究手段，求解了制造商的均衡订货决策和信息共享策略，分析比较了在不同的信息共享策略下制造商的利润、供应商的利润和批发价格。本文在研究制造商的信息共享策略时考虑了上游供应商的批发价格的影响。研究表明，当均衡解受到产能约束时，制造商的信息共享策略会反向。在某些情况下，完全信息共享和完全信息不共享都可能成为博弈的占优策略。上游供应商通过调整批发价格可以影响制造商的信息共享决策。该模型为上游供应商提供了一种最优定价策略，也为下游制造商提供了求解自身最优订货量和信息共享决策的方法。     

工艺设计质量信息不对称环境下质量激励合同设计

工艺设计质量决定了产品可制造性，从而对产品质量产生重要影响。在生产外包环境下，不仅供应商的质量努力难以合同化，而且工艺设计质量可能是设计者的私人信息，因此在供应商和制造商之间往往是不对称的，从而为质量激励合同设计带来挑战。本文考虑一个制造商和一个供应商构成的两级供应链。制造商可能自己设计产品，然后将生产外包给供应商，也可能将设计和生产都外包给供应商。本文分析了在这两种外包策略下，制造商的质量激励合同设计。研究发现：1）当工艺设计质量是对称信息时，制造商可以通过质量合同设计实现全局最优质量和利润；2）当工艺设计质量是制造商的私人信息时，工艺设计质量高的制造商可以通过降低对供应商的质量惩罚强度以及增加采购价格来传递工艺设计质量的信号；3）当工艺设计质量是供应商的私人信息时，制造商可以通过质量合同菜单来甄别工艺设计质量信息。与工艺设计质量是对称信息时的均衡合同相比，在针对低工艺设计水平供应商的合同中，制造商降低质量惩罚强度和采购价格；在针对高工艺设计水平供应商的合同中，质量惩罚强度不变，但采购价格提高。     

竞争供应链基于下游企业主导的纵向研发联盟研究

从博弈论的视角,构建2个强势制造商和2个排他性供应商组成的链与链价格竞争模型,研究竞争供应链基于利润分享合同的纵向研发联盟选择策略。研究表明,当市场竞争强度较低,或者市场竞争强度相对适中且研发效率较高时,形成纵向联盟结构链与链竞争均衡,该均衡为实现制造商和供应商利润Pareto改进的占优均衡。数值分析表明,随着竞争强度的减弱或者研发效率的提高,联盟的有效利润分享比例范围逐渐缩减。     

三级装备制造业供应链质量管理行为研究

作为我国工业化建设和国民经济发展的根本保证，供应链环境下装备制造企业的产品质量问题受到了广泛关注。本文重点考虑产品质量对供应链收益的影响，运用微分对策理论研究由单一制造商、单一部件供应商和单一零件供应商构成的三级装备制造业供应链质量管理行为的协调问题。通过对比Nash非合作博弈和Stackelberg主从博弈两种分散式决策模式及集中式决策模式下协同合作博弈的均衡结果，得到相关结论，并利用算例进行验证。研究表明，①分散式决策下，制造商的质量管理行为相同，但相比于Nash非合作博弈，Stackelberg主从博弈能够改善部件供应商和零件供应商的质量管理行为，提升供应链成员的收益水平；②集中式决策下，供应链成员的质量管理行为达到最优，系统整体收益实现最大。研究结论为装备制造业供应链成员间质量管理战略联盟的构建提供了理论依据。     

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.     

Power,authority and legitimacy

Management, human resources, organization, control, leadership, etc., all seem to be just so many euphemisms for power, and this suggests a discourse of management and organization that calls things by their proper name. This paper on the contrary stresses the need to resolve the concept of ‘power’ itself into more differentiated notions, and proposes that clarification may be derived from distinctions once explicit in the vocabulary of Classical antiquity, but lost in modern European languages. It argues that nothing but confusion in thinking about organizations, management and legitimation can result from the failure to recognize that the phenomena this vocabulary identifies and distinguishes are irreducibly different.     

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.     

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.     

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.