水平差异产品的内生定价策略选择

本文分析了一个存在定价策略选择下的三阶段Hotelling双头垄断模型,其中厂商可以选择采用单一定价策略或者歧视定价策略。模型的子博弈精炼纳什均衡表明厂商或者同时采用单一定价策略,或者同时采用歧视一价策略。当歧视定价的边际成本相对单一定价的边际成本不太高,或者消费乾注重产品特性差异时,厂商会同时选择歧视定价策略,尽管单一定价下厂商的利润要明显高于歧视定价下的利润;当歧视定价的边际成本相对较高或者消费者不太注重产品特性差异时,单一定价将成为厂商的最优选择。最后本文从社会最优的角度分析比较了两种这价策略下的社会净福利水平。     

运输成本内生化的三阶段Hotelling模型

本文分析了运输成本可由厂商内生决定的一个三阶段双头垄断的Hotelling模型,在[0,1]线性城市模型中,两个寡头垄断厂商在第一阶段进行选址决策,第二阶段改变线性运输成本,第三阶段进行价格竞争.并得到了与外生运输成本的二阶段模型不同的子博弈精炼纳什均衡结果.     

零售商水平竞争下二层供应链协调策略设计

研究一个生产商和两个零售商组成的二层供应链,生产商首先决定批发价和零售商选址约束,然后两个零售商进行选址和定价二阶段动态博弈。利用Hotelling模型得到了零售商价格竞争均衡的存在性条件,分析了集中式控制下供应链的最优选址和定价决策,提出了带转移支付的批发价合同和选址约束来协调零售商选取供应链最优决策。同时,带转移支付的批发价合同能激励零售商降低销售成本。     

寡头市场信息产品与服务的最优定价策略

在信息产品与服务竞争性市场中,信息产品及附加服务的定价策略日渐成为信息产品提供商关心的首要问题.而以往的研究多集中于单一信息产品的定价策略,没有统一考虑产品的后续服务,且假设消费者的网络外部性强度相同.分析了异质消费者和双寡头垄断市场,针对基础信息产品和附加服务的定价策略选择问题,建立了双寡头垄断市场中两个企业的捆绑销售和分别销售策略的博弈模型,使得双寡头企业通过4种局势下的策略选择实现收益最大化的定价策略.同时,将差异化网络外部性强度系数引入Hotelling模型,计算企业的需求函数和收益函数,并采用两阶段Bertrand博弈分析两个企业的定价策略和竞争行为.通过模型求解,得到4种局势下两家企业的最优定价解析解.通过数值模拟分析了潜在消费者的构成比例及市场规模对企业定价、市场占有率和最优收益产生的影响,以及不同成本和市场规模组合下企业的最优定价策略.     

策略型消费者创新感知与产品定价换代策略研究

科学技术迅猛发展促使厂商频繁推出创新型产品以抢占市场份额,产品定价和换代策略成为厂商经营成败的重要因素。本文在产品技术创新视角下构建双寡头厂商三阶段产品最优定价与换代决策模型,结合效用函数和博弈分析方法从同质产品市场拓展为异质产品市场,求解出单品换代策略及共生换代策略下新品上市时点和旧产品退出市场时点的显示解,并通过仿真模拟探讨产品技术创新水平、消费者创新感知度对最优产品定价和换代策略的影响。研究表明产品技术创新水平和消费者创新感知度对厂商产品定价和换代策略有重要影响。同质产品市场下,市场潜在需求越大,产品初始定价越高。厂商面临内外部产品竞争时,市场潜在需求较小且两代产品处于共生状态下,为减弱内部竞争新旧产品最优定价差距不大;当市场潜在需求较大,厂商新品定价由技术创新水平决定,消费者技术创新感知值越高,新品定价越高,反之越低。当厂商技术创新水平处于劣势时,两厂商技术创新水平差距越大,劣势厂商越应提早退出市场。     

社会地位效用及城市交通状况对私家车厂商市场策略的影响

私家车作为一种身份的象征,对私家车的消费能够体现消费者的社会地位,在私家车消费过程中一定程度上存在着对私家车所体现的社会地位的关注。这种炫耀性消费的存在,一定程度上说明了在交通拥堵带来不便的同时,为何我国的私家车销量却在逐年递增。从私家车的社会地位效用及城市交通拥堵对私家车使用的影响角度出发,通过构建微分博弈模型,分析社会地位效用及城市交通状况对私家车厂商市场策略的影响。研究结果表明：私家车厂商的最优动态定价及厂商的利润均随着社会地位效用的增加而增加,随着交通拥堵状况的增加而下降,并且社会地位效用及交通拥堵状况对高质量私家车厂商的影响大于对低质量私家车厂商的影响;随着两个厂商生产的私家车之间的质量差异不断增大,这种影响差异不断增大;厂商私家车的最优动态定价随时间的变化取决于社会地位效用及城市交通状况二者变动的关系。本文所得结论,对于私家车厂商制定正确的销售策略,以及地方政府部门制定合理的治理交通堵塞的措施,具有一定的借鉴意义。     

消费者策略行为视角下短生命周期产品的定价机制研究

本文从消费者策略行为出发,通过运用经典的Stackelberg博弈模型,讨论面对消费者策略行为时,短生命周期产品厂商如何有效进行收益管理.结论表明,在短生命周期产品收益管理过程中,忽视消费者策略行为会导致利润的严重损失,厂商应根据库存和消费者的理性预期制定相应的价格决策.当库存较少时,厂商基本可以忽略消费者策略行为而制定较高价格;当库存相对较多,厂商的最优定价决策依赖于理性预期均衡;当库存非常充裕时,最优定价决策与消费者折扣因子紧密相关.厂商可通过适当的库存数量增加产品缺货风险,而减少消费者策略行为的不利影响.这对短生命周期产品的收益管理具有一定的现实意义.     

双寡头垄断市场的信息安全投资模型研究

为考虑最优化信息安全投资对电子商务企业的市场竞争行为的影响,本文构建了一个双寡头垄断竞争两阶段博弈的信息安全投资收益模型,第一阶段厂商决定最优的信息安全投资及其收益,第二阶段厂商决定竞争价格.利用本文的最优化信息投资的决策方法分析了具有较高安全性的厂商具有较高的期望收益,证明了信息安全投资可以扩大市场需求和增加利润,并得出在寡占市场条件下的企业最优信息安全投资和均衡的市场价格,证明了率先进行信息安全投资的厂商可以成为市场的领导者的结论,这一理论结果符合现实的电子商务市场竞争结果.本文的信息安全投资模型与方法对在线厂商的信息安全投资决策的制定具有积极的指导作用.     

具有网络外部性特征的企业定价策略研究

随着信息技术的发展,传统经济中普遍采用的单一定价策略采用者正在逐渐减少,尤其在具有网络外部性特征的产业中,更多地采用歧视定价策略.针对具有网络外部性的产业中双寡头垄断厂商的定价策略选择行为,将传统Hotelling模型中外生的定价策略作为内生变量,分析了厂商对单一定价和歧视定价的战略选择.模型的子博弈精炼Nash均衡表明:当网络效应不存在时,厂商或者同时采用单一定价,或者同时采用歧视定价;当网络效应存在时,由于网络效应的影响,厂商选择歧视定价的均衡条件放宽,导致厂商采用歧视定价比单一定价更具有成本优势,从而增强了厂商选择歧视定价的趋向.另一方面,若消费者对产品特征的敏感程度加强,也促使厂商选择歧视定价.     

具有网络外部性的扩展Hotelling模型

将网络外部性引入线性运输成本下的Hotelling模型,研究了两家网络产品厂商首先选址,然后进行价格竞争的两阶段完全信息动态博弈问题,得到了厂商价格竞争均衡的存在性条件,推广了一般Hotelling模型的结论.由于网络外部性的存在,消费者效用是相互依赖的.网络产品的市场份额既是消费者选择的结果,又是消费者选择的依据.文章将交通流量分配技术和无穷维变分方法相结合,建立了刻画网络产品市场划分的模型——无穷维变分不等式,并研究了市场划分的存在性和唯一性问题.最后假定厂商定位在两端,分析了产品的网络外部性特征及单位运输成本对两个厂商竞争均衡情况的影响.     

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.