Towards Time-Aware Context-Aware Deep Trust Prediction in Online Social Networks

Trust can be defined as a measure to determine which source of information is reliable and with whom we should share or from whom we should accept information. There are several applications for trust in Online Social Networks (OSNs), including social spammer detection, fake news detection, retweet behaviour detection and recommender systems. Trust prediction is the process of predicting a new trust relation between two users who are not currently connected. In applications of trust, trust relations among users need to be predicted. This process faces many challenges, such as the sparsity of user-specified trust relations, the context-awareness of trust and changes in trust values over time. In this dissertation, we analyse the state-of-the-art in pair-wise trust prediction models in OSNs. We discuss three main challenges in this domain and present novel trust prediction approaches to address them. We first focus on proposing a low-rank representation of users that incorporates users' personality traits as additional information. Then, we propose a set of context-aware trust prediction models. Finally, by considering the time-dependency of trust relations, we propose a dynamic deep trust prediction approach. We design and implement five pair-wise trust prediction approaches and evaluate them with real-world datasets collected from OSNs. The experimental results demonstrate the effectiveness of our approaches compared to other state-of-the-art pair-wise trust prediction models.Comment: 158 pages, 20 figures, and 19 tables. This is my PhD thesis in Macquarie University, Sydney, Australi

How social media is changing political representation in the United Kingdom

Since the introduction of social media into everyday communication, a series of claims andcounterclaims have been made about its potential to either rectify or exacerbate the so-calledcrisis within representative democracy. Theoretical arguments suggest that social media mayincrease the closeness between representatives and citizens through more direct andcommunicative forms of representation. Based on these assumptions, this thesis seeks to assessthe ways social media has changed the conduct of political representation in the United Kingdom.It does this through an original methodological approach to answer research questions from theperspective of MPs (interviews), citizens (surveys), and social media data from three socialnetworks. This approach goes past previous literature on the use of social media that does notprovide either multi-platform analysis or encapsulate data from citizens to offer a bottom-upapproach.The results show that in many ways, MPs do not fully utilise Facebook, Twitter, or Instagram totheir expected potential. They seldom seek interpersonal dialogue with citizens, with onlymarginal increases in two-way communication attributable to social media. Instead, MPs arepursuing a strategy of broadcasting, limiting interactions to citizens who display positivesentiment towards the MP or their party: rejecting the notion that social media might foster theconcept of direct representation. Concurrently, the evidence suggests citizens might not beseeking to interact with MPs, as only a limited number of participants pursued communicationwith them. Instead, citizens seem to follow representatives for information gathering, news, orto show support. This implies that the crisis within representative democracy cannot be overcomeby interactive communication platforms alone.However, findings indicate that social media increases feelings of representation by citizens whenthey follow MPs. From this, social media is found not to provide representative benefits inexpected ways, but as a communication platform for a process of informational convergencewhich shapes the way citizens interpret the MPs they follow. This highlights a new way ofapproaching the benefits of representative communication towards a model in which what MPspost is of greater importance than levels of interactivity.Keywords: Political Communication; Political Representation; Social Media; Deliberative Representatio