Suicide ideation of individuals in online social networks

Suicide explains the largest number of death tolls among Japanese adolescents in their twenties and thirties. Suicide is also a major cause of death for adolescents in many other countries. Although social isolation has been implicated to influence the tendency to suicidal behavior, the impact of social isolation on suicide in the context of explicit social networks of individuals is scarcely explored. To address this question, we examined a large data set obtained from a social networking service dominant in Japan. The social network is composed of a set of friendship ties between pairs of users created by mutual endorsement. We carried out the logistic regression to identify users' characteristics, both related and unrelated to social networks, which contribute to suicide ideation. We defined suicide ideation of a user as the membership to at least one active user-defined community related to suicide. We found that the number of communities to which a user belongs to, the intransitivity (i.e., paucity of triangles including the user), and the fraction of suicidal neighbors in the social network, contributed the most to suicide ideation in this order. Other characteristics including the age and gender contributed little to suicide ideation. We also found qualitatively the same results for depressive symptoms.Comment: 4 figures, 9 table

Acceptance and Actual Use of "Facebook": The Role Social Identity and Altruism as Antecedent

The aims of this study are twofold. First, empirically examine how individual characteristics affect actual user acceptance of facebook. To examine these individual characteristics, this study apply a Technology Acceptance Model (TAM) to construct an amended model that focuses on two individual differences: social identity and altruism as antecedent of user acceptance. Next, examine the role users’ perception on intention to reuse. The result show that altruism significantly effect on acceptance of “facebook” whereas social identity partially effect on “facebook” acceptance. Perceived usefulness and perceived ease of use effect on intention to reuse.

Structural Micro Forces in Flickr Social Network

Previous studies on network structure of large online social networks focused almost exclusively on exploring the global network descriptive statistics. Few of the studies that have researched how these networks evolve from the micro forces at the local level have fallen short of modeling reciprocity and different ways triangle closure. By focusing on the denser areas of the Flickr network (user groups) and with the help of recently extended biased net modeling framework, we specified and fitted models and estimated parameters for all possible purely structural dyadic and triadic network effects: reciprocity, transitivity, structural similarity, closure and cyclicality. Our results showed that the reciprocity is by far the most strongest force acting in the network, followed by transitivity, closure and structural similarity. Cyclicality has been, surprisingly, proven not to exist at all. Furthermore, we have found that the size of the groups corresponds negatively with the magnitude of each of the micro forces. Keywords: Flickr, online networks, network structure, online social network

Competition Between Homophily and Information Entropy Maximization in Social Networks

In social networks, it is conventionally thought that two individuals with more overlapped friends tend to establish a new friendship, which could be stated as homophily breeding new connections. While the recent hypothesis of maximum information entropy is presented as the possible origin of effective navigation in small-world networks. We find there exists a competition between information entropy maximization and homophily in local structure through both theoretical and experimental analysis. This competition means that a newly built relationship between two individuals with more common friends would lead to less information entropy gain for them. We conjecture that in the evolution of the social network, both of the two assumptions coexist. The rule of maximum information entropy produces weak ties in the network, while the law of homophily makes the network highly clustered locally and the individuals would obtain strong and trust ties. Our findings shed light on the social network modeling from a new perspective

MOBILE SOCIAL NETWORK SERVICES: CHINESE USERS’ ADOPTION PATTERNS

Recent technological advancement in Telecommunications industry has enabled service providers and application developers to offer some of their services which used to be solely PC based for mobile devices as well. Given the prevalence of mobile data services, specifically mobile social network services, and application-stores such as Market (Andriod) and AppStore (Apple), it is crucial to understand user behaviour toward mobile service diffusion. The present study aims to investigate Chinese users’ behaviour toward mobile social network services, based on a sample of 212 respondents who used the most popular mobile social network services such as Tencent QQ in China. Our analysis suggests that each construct, perceived enjoyment, social influence, critical mass and mobile accessibility of social network service makes a unique contribution to our understanding of mobile social network service usage behaviour