Dynamics in online social networks

An increasing number of today's social interactions occurs using online social media as communication channels. Some online social networks have become extremely popular in the last decade. They differ among themselves in the character of the service they provide to online users. For instance, Facebook can be seen mainly as a platform for keeping in touch with close friends and relatives, Twitter is used to propagate and receive news, LinkedIn facilitates the maintenance of professional contacts, Flickr gathers amateurs and professionals of photography, etc. Albeit different, all these online platforms share an ingredient that pervades all their applications. There exists an underlying social network that allows their users to keep in touch with each other and helps to engage them in common activities or interactions leading to a better fulfillment of the service's purposes. This is the reason why these platforms share a good number of functionalities, e.g., personal communication channels, broadcasted status updates, easy one-step information sharing, news feeds exposing broadcasted content, etc. As a result, online social networks are an interesting field to study an online social behavior that seems to be generic among the different online services. Since at the bottom of these services lays a network of declared relations and the basic interactions in these platforms tend to be pairwise, a natural methodology for studying these systems is provided by network science. In this chapter we describe some of the results of research studies on the structure, dynamics and social activity in online social networks. We present them in the interdisciplinary context of network science, sociological studies and computer science.Comment: 17 pages, 4 figures, book chapte

Large-scale Social Network Analysis

Social Network Analysis (SNA) is an established discipline for the study of groups of individuals with applications in several areas like economics, information science, organizational studies and psychology. In the last fifteen years the exponential growth of on-line Social Network Sites like Facebook, QQ and Twitter has provided a new challenging application context for SNA methods. However, with respect to traditional SNA application domains these systems are characterized by very large volumes of data, and this has recently led to the development of parallel network analysis algorithms and libraries. In this chapter we provide an overview of the state of the art in the field of large scale social network analysis; in particular we focus on parallel algorithms and libraries for the computation of network centrality metrics

Dynamics of the coastal zone

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