中文摘要：

以中国最大的交易型网站淘宝网为平台，选取不同活跃度的交易型社区作为研究对象，从社会网络分析视角探讨不同社区活跃度下交易型社区成员之间关系网络的闭包机制。基于一般网络闭包相关理论，进一步考虑关系的方向以及交易型社区本身的信息性和功能性特征对其成员之间关系构建的影响。借助以Selenium为核心工具编写的爬虫程序，获取淘宝帮派网页上在同一主题下规模相似的4个具有不同社区活跃度的社区成员相互之间关系构建（相互关注和成为粉丝）的数据，运用图布局算法的Gephi软件，将所有样本社区的整体关系网络结构进行可视化呈现，通过构建关系形成概率的风险模型和基于SAS9．2工具的参数检验得到研究结论。研究结果表明，活跃度较低的交易型社区内成员之间的关系网络闭包主要受选择性影响机制的驱动，而基于互惠性和传染性的社会性影响对成员的关系构建都具有负向的影响；活跃度较高的交易型社区内成员之间的关系网络闭包会同时受到社会性影响和选择性影响的驱动，并且社会性影响比选择性影响具有更强的作用；不论是在活跃度较低还是活跃度较高的交易社区，社会性影响和选择性影响的交互影响对社区成员的关系网络闭包具有显著的正向影响。这些研究结果可以帮助交易型社区的管理者和参与者从宏观角度观察社区的整体结构及其动态演化过程，同时也能从微观角度了解社区中成员之间相互关系构建的规律。

英文摘要：

This research, based on the most active communities in the largest platform of e-business in China （ Taobao. corn） , analyzed the differences of transactional community in the network closure mechanisms from different levels of community activities. Based on the network closure literatures, the authors take the directions of relationships and the informational and functional characteristics in transactional communities into considerations and explore their effects on the network closure among the members in transactional community. By using the Web-crawler tool and from the perspectives of social network analysis, the authors collect- ed the network data from four sampled transactional communities with the similar community size under the same community is- sue. The results show that the major differences among the sampled transactional communities rely on the levels of their community activities. The authors apply Selenium, open source software programmed, to collect the static online information from the sampled four transactional communities. After the authors visualized the general structures of all the sampled transactional communities, which is based on the software of Gephi, we build up the hazard model to account for the probabilities of established relationships from a dynamic view. Then, the authors apply the statistics tool of SAS 9.2 to test the hazard model built up previously. Hence, the authors get the major results as follows： （~）in the less active transactional communities, the network closure among the members in the communities is mainly driven by the mechanism of selection effect, while both the reciprocity and contagion in social influence have negative effects on network closure among the members in transactional communities; （1）in the more active transactional communities, the network closure among the members in the communities is mainly driven by the mechanisms of both selection effects and social influences, while the social influence, such as reciprocity and contagion, has