The immense popularity of today's social networks has lead to the availability and accessibility of vast amounts of data created by users on a daily basis. Various types of
information can be extracted from such data, for example, interactions among users, topics of user postings,
and geographic locations of users. While most of the existing works on social network analysis, in particular those focusing on social links and communities, rely on explicit and static link structures among users,
extracting knowledge from exploiting more features embedded in user-generated data is another important direction that only recently has gained more attention.
Initial studies employing this approach show good results in terms of a better understanding latent interactions among users.
In the context of this dissertation, multiple features embedded in user-generated data are investigated
to develop new models and algorithms for (1) revealing hidden social links between users and (2)
extracting and analyzing dynamic feature-based communities in social networks.
We introduce two approaches for extracting and measuring interpretable and meaningful
social links between users. One is based on the participation of users in threads
of discussions. The other one relies on the social characteristics of users as reflected in their postings.
A novel probabilistic model called rLinkTopic is developed to address the problem of extracting
a new type of feature-based community called regional LinkTopic: a community of users
that are geographically close to each other over time, have common interests indicated by the topical
similarity of their postings, and are contextually linked to each other.
Based on the rLinkTopic model, a comprehensive framework called ErLinkTopic is developed that allows
to extract and capture complex changes in the features describing regional LinkTopic communities, for example, the community membership of users and topics of communities.
Our framework provides a novel basis for important studies such as exploring social characteristics of users in geographic regions
and predicting the evolution of user communities.
For each approach developed in this dissertation, extensive comparative experiments are conducted using data from real-world social networks to validate
the proposed models and algorithms in terms of effectiveness and efficiency. The experimental results are further discussed in detail to show improvements over
existing approaches and the applicability and advantages of our models in terms of learning social links and communities from user-generated data