Empirical Analysis of Indirect Network Effects in the Market for Personal Digital Assistants

We present a framework to measure empirically the size of indirect network effects in high-technology markets with competing incompatible technology standards. These indirect network effects arise due to inter-dependence in demand for hardware and compatible software. By modeling the joint determination of hardware sales and software availability in the market, we are able to describe the nature of demand inter-dependence and to measure the size of the indirect network effects. We apply the model to price and sales data from the industry for personal digital assistants (PDAs) along with the availability of software titles compatible with each PDA hardware standard. Our empirical results indicate significant indirect network effects. By July 2002, the network effect explains roughly 22% of the log-odds ratio of the sales of all Palm O/S compatible PDA-s to Microsoft O/S compatible PDA-s, where the remaining 78% reflects price and model features. We also use our model estimates to study the growth of the installed bases of Palm and Microsoft PDA hardware, with and without the availability of compatible third party software. We find that lack of third party software negatively impacts the evolution of the installed hardware bases of both formats. These results suggest PDA hardware firms would benefit from investing resources in increasing the provision of software for their products. We then compare the benefits of investments in software with investments in the quality of hardware technology. This exercise helps disentangle the potential for incremental hardware sales due to hardware quality improvement from that of positive feedback due to market software provision.     

On the optimal taxation of common-pool resources

Recent research developments in common-pool resource models emphasize the importance of links with ecological systems and the presence of non-linearities, thresholds and multiple steady states. In a recent paper Kossioris et al. (2008) develop a methodology for deriving feedback Nash equilibria for non-linear differential games and apply this methodology to a common-pool resource model of a lake where pollution corresponds to benefits and at the same time affects the ecosystem services. This paper studies the structure of optimal state-dependent taxes that steer the combined economic-ecological system towards the trajectory of optimal management, and provides an algorithm for calculating such taxes.     

浅谈建设工程合同形式对工程造价的影响

不同的合同结构形式对工程造价有不同影响,选择哪种合同结构形式需考虑影响造价的主要因素有,业主自身的管理团队、总包单位的能力、减免税费、项目开办费等。     

数控机床进给伺服系统的典型故障及诊断

数控机床是典型机电一体化产品,故障出现的种类和原因很多,其中进给伺服系统故障所占比重较大,文中主要以典型的进给伺服系统故障为例,总结、分析引起伺服系统故障的原因,并提出解决的思路和办法。     

网络经济正反馈系统动力学模型分析

随着计算机网络技术飞速发展,网络化和全球化已成为不可抗拒的世界潮流。网络经济正渐渐取代传统的工业经济,人类社会正在迈向网络经济时代。网络经济作为一种新经济形态,存在着与传统经济不同的新特点。本文从系统动力学观点出发,在分析网络经济基础上,提出了网络经济正反馈系统动力学模型,探讨了正反馈效应带来的网络经济新特点。     

How Online Product Reviews Affect Retail Sales: A Meta-analysis

A growing body of research has emerged on online product reviews and their ability to elicit performance outcomes desired by retailers; yet, a common understanding of the performance implications of online product reviews has eluded us. Scholars continue to navigate an array of studies assessing different design elements of online product reviews, and various research settings and data sources. We undertake a meta-analysis of 26 empirical studies yielding 443 sales elasticities to examine how these variables relate to retail sales. Building on well-established meta-analytical methods, we address the following questions: How does review valence influence the elasticity of retailer sales? What about review volume? For which product types and usage situations do online product reviews have a greater impact on retailer sales elasticity? Which types of online reviewers and websites exert the greatest influence on retailer sales elasticity? Our study answers these important questions and provides a much needed quantitative synthesis of this burgeoning stream of research.     

Facebook fan page: the effect of perceived socialness in consumer–brand communication

Facebook has become an important platform for a brand–consumer relationship channel. The current study investigates the influence of perceived socialness and its effect on consumers’ attitude toward brands. Participants (N = 404) were recruited in a large southeast university. A 2 (socialness: high vs. low)?×?2 (feedback control: high vs. low)?×?2 (brand image: high vs. low) between-subject design was conducted. The results of this study identified three important findings. First, high (vs. low) socialness elicited higher perceived relationship commitment, brand trust, and more favorable brand attitude. Second, the effect of socialness on brand attitude was moderated by brand image (positive vs. negative). Third, the mediation analysis showed that the effect of socialness (high vs. low) on brand attitude was fully mediated by perceived relationship commitment and brand trust.     

中国房地产泡沫与非泡沫--以投机理论为基础的实证分析

文章在对当前房地产泡沫若干观点作简单综述和对房地产泡沫定义辨析的基础上,建立了房地产投机泡沫检验模型,并对中国房地产业泡沫性与非泡沫性进行了实证研究,最后得出当前中国房地产业不存在投机泡沫的结论。     

Youth Poverty,Employment, and Leaving the Parental Home in Europe

This paper studies the nature of youth poverty dynamics in Europe. First, it analyzes to what extent experiencing poverty in a given period is in itself positively related to the probability of living below the poverty line again in the future. That is, we assess the degree of poverty genuine state dependence among young people. Second, we study the interrelationships between poverty, employment, and residential emancipation. The results show that youth poverty genuine state dependence is positive and highly significant, but this scarring effect is short‐lived in Scandinavia compared to Southern or Continental Europe. Moreover, although we find a strong association between poverty and leaving home in Nordic countries, time spent in economic hardship does not last long. On the contrary, in Spain and Italy, young adults tend to leave their parental home much later in order to avoid falling into a poverty state that is more persistent.     

Effects of teleconferencing technologies: An exploration of comprehension,feedback, satisfaction and role-related differences

Several theoretical approaches have been put forth to predict and explain the effects of teleconferencing technologies. One approach is to examine the functions of nonverbal signals and to make predictions based on the fact that different teleconferencing technologies allow nonverbal communication to different extents. One of the functions of nonverbal signals is to allow the listener to provide feedback to the speaker in a communication. Prior research has shown that such feedback enhances listener comprehension. In this study, it was hypothesized that different teleconferencing technologies would allow different levels of feedback based on their ability to accommodate nonverbal signals, and this in turn would affect comprehension. An experimental study was conducted to compare comprehension, feedback, and satisfaction in telephone and computer conferencing. The study confirmed that comprehension and speaker satisfaction are related to feedback, but failed to show a relationship between listener satisfaction and feedback. No difference in comprehension, listener, or speaker satisfaction was observed across teleconferencing technologies. Role-related differences were observed between the speaker and the listener. It is suggested that the effects of teleconferencing technologies can be mapped systematically by examining each of the functions of nonverbal signals, one at a time.