网络型市场结构下企业Cournot均衡产量决策研究

本文提出的网络型市场结构不仅克服了传统市场结构分析中割裂产业问联系的缺陷,同时也修正了供应链中忽视同行业之间相互作用的弊端,并进一步提出了网络型市场结构一般模型。进而,构造了两个具有代表性的“一市场两产业三企业”网络型市场结构模型,从（竞争,竞争,竞争）、（竞争,合作,合作）、（合作,合作,竞争）及（合作,合作,合作）四种策略组合对网络型市场结构下Cournot均衡产量和传统市场结构下Cournot均衡产量决策进行了对比。得出,网络型市场结构下企业Cournot均衡产量小于传统市场结构下企业Cournot均衡产量的结论,并通过算例对该结论进行了验证。     

双寡头垄断市场的价格竞争与产品差异化策略——一个博弈论模型及其扩展

分析三阶段Bertrand-Stackelberg市场价格竞争与产品差异化选址策略,将之与Bertrand-Nash市场均衡进行静态比较;其次,构造一个具体的数字例子,演示随着产品差异化程度的提高,双寡头垄断市场中企业均衡利润的变动规律.在此基础上,识别经典的产品差异化定位博弈模型的各种假设条件,并在放松假设以讨论存在边际成本优势、消费者选择行为以及重复动态博弈的情形下,寡头垄断市场中的企业均衡利润和均衡价格的变化趋势及其稳定性问题.放松传统模型的假设条件有助于完整地理解和分析许多长期被孤立研究的产业竞争问题.     

政府市场规制、产品消费选择和企业绿色技术创新

本文通过构建由地方政府、企业和消费者组成的绿色技术创新系统演化博弈模型,分析了不同现实情形下系统的均衡策略演化过程,并借助系统动力学实验方法进一步研究了相关因素对系统均衡的影响。研究发现:(1)在绿色技术创新演化博弈系统所有可能的均衡策略中,只存在三个稳定的均衡策略,即地方政府、企业和消费者的策略分别为(市场规制,不绿色技术创新,购买传统产品)、(市场规制,绿色技术创新,购买传统产品)、(市场规制,绿色技术创新,购买绿色产品)。(2)企业绿色技术创新品牌收益和消费者绿色产品消费的经济收益是影响博弈演化系统最终向不同稳定均衡策略演进的主要因素。(3)在第一种均衡状态下,产品的基础价值、绿色偏好收益、绿色消费意识和产品价格等是影响消费者购买绿色产品的主要因素;在第二种均衡状态下,政策收益、规制成本及产品市场需求量是影响政府采取市场规制策略的主要因素;在第三种均衡状态下,绿色技术创新补贴系数、市场规制强度和企业绿色技术创新品牌收益是影响企业采取绿色技术创新策略的主要因素,且各影响因素对博弈主体策略选择的方向和边际的影响均存在较大差异。上述结论将为进一步完善绿色发展理论提供参考,也为构建市场导向的绿色技术创新体系提供借鉴。     

不完全需求信息下的寡头发电商报价学习模型

基于发电商主观推断得到的市场清除价与市场实际价格之差异,构建发电商报价学习模型,并对该模型的不动点及其稳定性进行了解析分析;在此基础上,针对存在2个发电商的报价市场,对学习模型的稳定域、分岔图和平均收益等复杂性现象进行了数值仿真分析.结果表明:学习模型唯一的不动点即为客观的市场需求曲线;在稳定域内发电商通过学习模型可发现客观的市场需求曲线,并得到Cournot均衡策略;在混沌状态下,有发电商获得超过Cournot均衡的平均收益,也有发电商获得少于Cournot均衡的平均收益,且可能形成一个新的Nash均衡.     

噪音交易、认知偏误与市场波动--基于一个状态可变经济

以世代交叠模型为基本框架,引入理性交易者与噪音交易者来考察股票市场的波动性.真实经济过程在两种状态之间转换,但由于噪音交易者存在认知偏误,他们对不同状态下的随机经济发生概率具有错误的主观信念,而且不同的信念也对期望方差有影响.在市场达到均衡时,根据不同状态的价格差发现首先,经济中的波动性均来自噪音交易者对真实经济的认知偏误,当市场只存在理性交易者时,市场均衡价格保持不变且与经济状态无关,也即市场不存在波动;其次,通过对模型进行的数值模拟可以发现,噪音交易者的认知偏误度、经济状态发生概率和各主体市场份额都对波动有不同影响,因此模型为资产的波动性提供了新的解释.还对进行经验检验的可行性进行了探讨.     

非均衡交通规划初探

传统交通规划以微观经济学瓦尔拉斯均衡原理作为理论基础 ,交通规划是针对市场均衡点进行展开的 ,不涉及非均衡区域 .实际上 ,均衡状态是一种特殊的非均衡 ,在一定的市场条件下才能实现 ,即使实现了 ,也是暂时的 ,它不能代表真实的市场情况 .鉴于运输市场非均衡的普遍存在性 ,本文根据非均衡理论及相关研究成果 ,提出了非均衡交通规划的思想 .通过对市场调控机制的分析 ,研究了运输市场非均衡的存在性 ;利用变分不等式对均衡与非均衡的统一性进行了等价描述 .提出了非均衡交通需求预测的思想 ,并将非均衡价格——数量调节行为原理引入到传统的用户路线选择行为之中     

最优网上拍卖机制模型研究

最优拍卖机制设计问题是拍卖人通过合理的设计一系列规则使得自己的收益最大化的过程,这一过程显然是追求"卖方剩余"最大化的.实际上,在拍卖人追求收益最大化的同时,竞标人同样会通过最优策略的分析,使自己的收益最大化.这种双方博弈的结果自然导致一种均衡状态的出现,这种均衡状态是一种纳什均衡状态,这种状态下的社会资源配置也是最优的.本文试图从传统的网上拍卖模型入手,将原有模型进行扩展研究,得出拍卖品数量和拍卖价值离差等对网上拍卖的影响,从而提出一个现有电子商务环境下的最优拍卖机制模型.     

基于不同预期报价决策的电力市场动态演化及其混沌控制

基于市场参与者不同预期的报价决策方式,提出了考虑输电网约束的电力市场动态模型,即内嵌市场清算优化问题的差分动态模型.该模型刻画出发电方和需求方同时报价的不用决策行为,并准确反映出独立系统调度员ISO的统一市场清算过程,考虑了输电网固有物理特性所赋予电力市场的复杂约束.借助非线性互补函数,对应不同的输电网运行状态:阻塞和不阻塞,分析比较了电力市场处于Nash均衡、周期和混沌的经济表现.针对经济表现差的市场混沌态,提出电力市场状态和参数时滞反馈控制方法,给出电力市场由混沌到Nash均衡的调控措施和手段,从而为有效提高电力市场的经济效益提供了理论依据.     

住房保障政策选择的动态分析模型

在中央计划者经济框架内,将无房户率引入效用函数,构建关于公共住房投资和租金补贴的最优增长模型.通过中央计划者的最优决策得到均衡状态,给出均衡状态下的模型最优解和鞍点路径,得出公共住房存量增长对无房户率的影响规律.结论显示,住房保障政策的选择与住宅市场发展阶段、住宅市场供给状况、政府偏好等因素密切相关.这为我国住房保障政策的制定与实施提供了依据.     

基于投资者观点的鲁棒性投资组合选择模型

Black-Litterman模型因其将投资者观点和市场均衡收益率结合分析的特点广受关注和应用,本文从均衡收益率和投资者观点的不确定性及参数的不确定性两方面对该模型进行鲁棒性建模。首先,本文对于投资者观点及资产均衡收益率进行鲁棒性建模,进而对资本市场均衡收益率进行深度分析,其次对风险厌恶系数进行鲁棒性建模,并基于运筹学理论将模型转化为有成熟算法的二阶锥规划问题。最后基于实际数据给出数值算例,佐证了模型的有效性。     

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.