基于网络效应的竞争性产品微观扩散研究

竞争性产品扩散是成熟市场的重要表现,网络效应的存在不仅改变了传统的扩散模式, 而且对个体采纳行为有重要影响． 但是以往研究竞争性产品扩散侧重于宏观层面的扩散速度和扩散效果,忽略了微观层面个体的个性以及社会交互等特点对产品扩散的影响,因此需要基于网络效应从个体微观层面研究竞争性产品扩散的特点． 首先构建了基于个体间交往关系的直接网络效应函数和基于多种互补产品协同作用下的间接网络效应函数,然后,个体将计算自己当前时刻的收益以及下一时刻的预期收益,并根据预期社会化效益满意决策机制确定下一时刻的产品选择． 通过仿真对扩散系统进行研究,结果表明: 直接网络效应和间接网络效应对竞争性产品扩散具有阶段性影响; 在小世界网络的社会交往结构中竞争性产品扩散效果最好; 个体人数分布、偏好、对环境的判断都对竞争性产品扩散有重要影响．     

服务的空间扩散: 基于上海迪士尼的实证

体验经济是当代企业服务营销的重要组成,由于服务体验的扩散具有明显的空间效应,本研究通过建立服务扩散的空间溢出模型,在其中定义区域间的相对影响力和易感性,从而准确分离了本地区服务体验扩散和其他地区溢出扩散这两种空间影响效果.研究基于上海迪士尼乐园游客的移动数据,实证测量了迪士尼服务群体的空间扩散效应、省份和区域层次服务扩散的影响力、易感性与溢出效应.结果发现,迪士尼乐园服务群体的扩散效果主要受到本地游客的直接影响(占比38.6%)和来自其他地区游客的溢出影响(占比52.4%),受到的时间效应和媒体效应为8.7%和0.3%.此外,该模型还给出了各省游客对迪士尼服务效果传播的不同影响力,以及各省游客对该服务传播的易感性.本研究证实了服务扩散过程中地区空间影响的不对称性,开发的定量模型也为服务业营销人员进行以空间地理为导向的干预措施提供了精准参考.     

间接网络效应下的产品扩散——基于复杂网络和计算经济学的研究

借鉴复杂性理论,基于个体交往关系的复杂网络结构,该文采用计算经济学建模方法和行为博弈学习算法对间接网络效应下的产品扩散现象进行建模.在该文模型中,间接网络效应下"软件"数量为厂商策略行动内生决定,并根据用户数量而变化,因此个体的决策和全局变量之间存在双向交互复杂作用.研究结果揭示了个体邻域结构在产品扩散中的影响,直接网络效应和间接网络效应在产品扩散中的区别和产品锁定发生的条件等.结果也较好地解释了产品扩散中的很多现象如不同产品的共存,产品扩散中的"涌现",产品扩散中的路径依赖,产品兼容性的选择以及新旧产品的更新换代等.     

社会群体多维剥夺感模型及应用

相对剥夺感研究对于构建和谐社会具有重要的理论和现实意义。本文首先综述分析了社会个体单维剥夺感模型(SISDM)、社会个体多维剥夺感模型(SIMDM)和社会群体单维剥夺感模型(SGSDM)等社会剥夺感研究领域的三大模型;然后,本文在Betti和Verma提出的社会个体多维剥夺感模型以及Elena和Lius等人提出的社会群体单维剥夺感模型基础上,建立了综合考虑横向和纵向剥夺感的社会群体多维剥夺感模型。最后,本文通过实证表明,新模型能够客观全面地反映社会群体的实际状况,可以为和谐社会建设提供客观的决策依据。     

我国动态利率期限结构的实证研究——基于离散时间的三因子QTSM模型的应用

本文在扩展的卡尔曼滤波法及拟极大似然估计法的基础上,首次把离散时间下三因子二次方形式的动态利率期限结构模型应用于上交所国债期限的研究,并在二次方利率期限结构框架内比较了常数型、仿射型和二次方型市场风险函数对不同利率期限结构的拟合效果.我们发现二次方市场风险对1年期利率拟合的最好;对2年期利率的拟合,常数型和仿射型市场风险比二次方市场风险表现更佳;而对3、4、5年期利率的拟合,仿射型市场风险表现最好.     

适应性预期、复杂网络与标准扩散动力学——基于计算经济学的研究

标准扩散是现代产业经济中的重要问题.主要采用复杂网络的小世界网络模型和基于agent的计算机建模技术,结合行为博弈学习理论中的EWA算法,对网络外部性下标准扩散过程中的适应性预期进行研究.基于个体在局部网络中的交互作用和个体行为的学习演化与预期自适应调整,通过计算机仿真就适应性预期对标准扩散的影响从多方面进行分析.研究结果揭示了个体适应性预期在标准扩散中的重要作用,发现扩散中的"涌现"现象,个体邻域结构的随机性对标准扩散结果及其最终分布状态有很大的影响,个体预期能够逆转标准扩散中的先发优势,预期速度调整因子在不同预期强度下有完全不同的影响,个体对新标准的较高预期也是新标准得以扩散的必要条件.     

SSTs情境下顾客技术准备的结果模型

已有研究探讨了顾客技术准备对顾客采用、尝试自助服务技术(SSTs)的影响,而忽视了其引发的结果。研究借鉴人力资源管理当中相关概念和成果,构建自助服务技术情境下顾客技术准备的结果模型,并通过收集248名网上银行使用者的数据,利用偏最小二乘法(PLS)进行结构方程建模来验证假说。研究结果表明在自助服务技术情境下,顾客技术准备对顾客感知的SSTs服务质量、感知价值、顾客满意有显著的正向作用;而对感知风险则有负向影响。各个结果变量之间的关系也都符合传统服务营销领域中的研究结果,除了感知价值和感知风险之间的关系。由于受到性别的调节作用,感知价值与感知风险没有出现研究所期望的负向关系。研究结论为未来自助服务技术研究和实施有效的自助服务技术管理提供借鉴。     

在线到移动环境下消费接受行为的演化研究:基于计算实验方法

构建实证数据驱动下的多智能体计算实验平台,用于研究从在线到移动环境下消费转移行为的动态演化机理。实验结果表明,所收集的实验数据与经典扩散方程拟合程度高,说明计算模型能反映真实系统的演化过程。广告在产品/服务的市场投放初期效果明显,随着广告强度的增加,消费接受效果并非明显。当市场中出现高消费休眠时,即便采用高唤醒策略,其移动服务消费接受水平也低。当休眠率远大于唤醒率时,市场成熟期后,移动产品/服务接受量下降,而在线产品/服务接受量回升。当唤醒率远大于休眠率时,移动产品/服务接受量水平可达到最大,并维持稳定。该计算模型和实验结果能为管理者提供电子商务行为决策方面的支持。     

组织网络隐性知识扩散及学习策略分析

知识主要以显性知识和隐性知识两种方式存在,隐性知识是组织获得竞争优势的主要源泉.隐性知识为组织个体所拥有,这种私有性的特征使其在组织内部的扩散需要通过组织个体之间的交互才能完成.组织网络连接强度对扩散具有影响,可利用具有边权重的组织网络研究隐性知识的扩散行为.在分析隐性知识和相关扩散特点的基础上,基于组织成员之间的关系网络和小世界网络模型,建立组织网络上的知识扩散模型.根据认识论的观点,提出个体3种知识学习策略,结合知识扩散模型进行计算仿真实验.仿真结果显示,综合考虑关系和知识差别的知识学习策略最有效,不考虑连接强度下的各种策略都具有较快的知识学习速率,并且连接强度对组织内隐性知识扩散具有明显的作用.     

广告媒介下两种产品竞争与扩散模型研究

本文基于巴斯模型在非垄断情形所遇到的产品扩散问题,提出了在广告媒介下两种产品的竞争与扩散模型,并对不同情况下产品竞争扩散过程进行了经济分析,推广了单产品巴斯扩散模型.为模拟和预测动态市场结构演变提供了理论依据.     

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.     

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.     

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.