Multiple aspect testing for case-control designs

When testing for the equality of two distributions in a case-control design with treatment effects presumed to act possibly on more than one aspect, different tests may be properly considered for testing for different features of a null hypothesis, leading to the multiple aspect testing issue. Two different aspects are therefore of interest: the location-aspect, based on the comparison of location indexes, and the distributional-aspect, based on the comparison of the empirical distribution functions. A simulation study shows that the combined testing procedure exhibits a good robust overall performance, and an application in biomedical research is also presented.     

The evolution of the intellectual structure of operations management—1980–2006: A citation/co-citation analysis

Citation analysis combined with a network analysis of co-citation data from three major operations management (OM) journals is used to reveal the evolution of the intellectual structure of the OM field between 1980 and 2006. This spans the entire time since the beginning of research journals specific to the field. Employing a bibliometric citation/co-citation analysis to investigate the foundations of the discipline enables a robust, quantitative approach to uncovering the evolution of research in OM. The study finds that the intellectual structure of the field made statistically significant changes between the 1980s, the 1990s, and the 2000s and evolved from a pre-occupation with narrow, tactical topics toward more strategic, macrotopics, including new research methods and techniques. A factor analysis identifies the 12 top knowledge groups in the field and how they change over the decades. Illustrations of the structure of the co-citations representing the field are generated from a spring-embedded algorithm that is an improvement over the standard multi-dimensional scaling (MDS) approach to illustrating the knowledge groups.     

Heterogeneity and centrality of “dark personality” within teams,shared leadership,and team performance: A conceptual moderated-mediation model

Shifting from the much-studied five-factor model of personality, this paper focuses on dark personality (i.e. the “Dark Triad”: Machiavellianism, psychopathy, and narcissism) to advance understanding of team composition, processes, and performance. The research responds to a call to explore dark personality's manifestation within – and impact on – teams. Specifically, this paper will examine the impact of within-team heterogeneity in dark personality on team performance, with shared leadership as mediator of this relationship. Additionally, I propose two moderators of the relationship between within-team dark triad heterogeneity and shared leadership – team network centrality of the team member scoring highest on the Dark Triad, and team mean Dark Triad score. This research aims to make a uniquely valuable contribution to scholarship on leadership within teams through bridging literatures on social network analysis, teams, leadership, and the dark triad and should have implications for team selection and performance.     

Hierarchical structures of communication in a network organization

We analyze the intranet communication behavior of members of a company that was deeply committed to the principles of non-hierarchical communication structures and of post-bureaucratic organization. We observe a split between the symbolic activities for creating a non-hierarchical network organization and the actual intranet communication behavior of the organization members. In their daily communication on the intranet, they persistently reproduced hierarchical structures and official channels—elements typically associated with bureaucratic organizations. Further, we find many signals in the content of the intranet messages, reflecting a social hierarchy that has evolved within the organization. Thus, despite rhetoric to the contrary, our findings regarding this communication behavior show that, to all intents and purposes, this particular organization displayed characteristics similar to those of a traditional bureaucratic organization.     

Job matching, social network and word-of-mouth communication

Workers can find a job either directly or through personal contacts. From this micro scenario, we derive an aggregate matching function that has the standard properties but fails to be homogeneous of degree one. We show that, when the network size increases, on average, the unemployed workers hear about more vacancies through their social network. However, above a certain critical value, job matches decrease with network size. We then establish existence and uniqueness of the labor market equilibrium and study its properties. Finally, we demonstrate that the decentralized market equilibrium is not efficient because of both search and network externalities.     

Link analysis: Hyperlink patterns and social structure on politicians’ Web sites in South Korea

This paper presents results of an investigation into political communication expressed by links connecting politicians’ web sites with the sites of other political actors in South Korea. Additionally, this study examines whether a set of socio-demographic variables for web site producers is associated with linking behavior. Both traditional methods and social network analytical techniques are employed to investigate linking patterns between sites. Perhaps unsurprisingly, members of the South Korean National Assembly linked most to party web sites, and linking patterns did not change between 2003 and 2004. Out of a range of demographic variables investigated, the only ones that related significantly to linking practices were party affiliations and friendship networks.     

Understanding supplier structural embeddedness: A social network perspective

Despite a significant amount of attention, the potential of supplier structural embeddedness (i.e., the value of the structural position in an extended network) to improve the performance of a buying firm remains poorly understood. This study drew on the social network theory to empirically examine a conceptual framework specifying a relationship between the efforts of a buying firm to understand supplier structural configuration and operational and financial performance. This study also examines how the comprehension of structural embeddedness is transformed into performance for a buying firm through relational embeddedness (i.e., the strength of a dyadic relationship). Survey data collected from companies in the U.S. were analyzed using hierarchical regression analysis. The results indicate that the understanding of the structural dimension does help to enhance operational performance of a buying firm, but it does not lead to better financial performance. Empirical evidence shows that a buying firm does improve the quality of a dyadic relationship between the buying firm and a supplier by understanding how the supplier is connected to other firms and what positional values are produced. Further, relational embeddedness is found to mediate the influence of the enhanced understanding of the structural configuration on operational performance.     

Structural investigation of supply networks: A social network analysis approach

A system of interconnected buyers and suppliers is better modeled as a network than as a linear chain. In this paper we demonstrate how to use social network analysis to investigate the structural characteristics of supply networks. Our theoretical framework relates key social network analysis metrics to supply network constructs. We apply this framework to the three automotive supply networks reported in Choi and Hong (2002). Each of the supply networks is analyzed in terms of both materials flow and contractual relationships. We compare the social network analysis results with the case-based interpretations in Choi and Hong (2002) and conclude that our framework can both supplement and complement case-based analysis of supply networks.     

可信软件分析与测试研究现状及发展趋势

本文通过对可信软件的现状和发展趋势研究,从可信软件可靠性分析技术、软件可信性评估技术、软件可信性测试与验证技术等方面详细分析了软件可信的国内外研究现状和发展趋势。     

极端波动情景中的压力测试和极值理论方法研究

VaR描述的是市场正常波动情况下的资产组合最大可能损失,指出了不利事件发生的概率,但没有说明不利事件发生时的实际损失到底有多大。为了测量在这些小概率极端情况下的风险,本文对当前测量极端波动情景中较为先进的情景分析、系统化压力测试和极值分析方法进行较为全面的研究。