7,525 research outputs found
Efficiently reinforcing social networks over user engagement and tie strength
© 2018 IEEE. User engagement and tie strength are fundamental and important components in social networks. The model of k-Truss not only captures actively engaged users, but also ensures strong tie strength among these users. It motivates us to utilize the model of k-Truss in preventing network unraveling, which simultaneously considers both of the basic components. In this paper, we propose and investigate the anchored k-Truss problem to reinforce a network by anchoring critical users who can significantly stop the unraveling. We prove the problem is NP-hard for k ≥ 4. A fast edge deletion order based algorithm, named AKT, is proposed with efficient candidate exploration and pruning techniques based on the order. Comprehensive experiments on 10 real-life graphs demonstrate the effectiveness of our model and the efficiency of our methods
Cohesive subgraph mining on social networks
University of Technology Sydney. Faculty of Engineering and Information Technology.Graphs are widely used to represent the abundant information in social networks for discovering promising communities, reinforcing network stability, and finding critical users, to name a few. Cohesive subgraph mining, as one of the most fundamental problems in graphs, gains increasing popularity in social network study for its effectiveness. In this thesis, some basic social components are considered in cohesive subgraphs to better accommodate various real-life applications.
Firstly, we investigate the problem of (k,r)-core which intends to find cohesive subgraphs on social networks considering both user engagement and similarity. Efficient algorithms are proposed to enumerate all maximal (k,r)-cores and find the maximum (k,r)-core, where both problems are shown to be NP-hard. Effective pruning techniques and search orders substantially reduce the search space of two algorithms. A novel upper bound enhances performance of the maximum (k,r)-core computation. Comprehensive experiments on real-life data demonstrate that the algorithms efficiently find interesting communities.
Secondly, we study the problem of the anchored k-core, which was introduced by Bhawalkar and Kleinberg et al. in the context of user engagement in social networks. The problem has been shown to be NP-hard and inapproximable. We propose an efficient algorithm, namely OLAK, as the first to solve the problem on general graphs. An onion layer structure is designed together with efficient candidates exploration, early termination and pruning techniques to significantly simplify computation and greatly reduce the search space.
Besides considering user engagement, we further explore the unraveling phenomenon with tie strength, which leads us to the model of k-truss. We then investigate the anchored k-truss problem which is also NP-hard and propose an edge onion layer structure based algorithm, namely AKT. Efficient candidate exploration and pruning techniques are designed based on the edge onion layers. Comprehensive experiments on real-life graphs for the above two problems demonstrate the effectiveness and efficiency of our proposed methods.
Finally, we study the leave of critical users, which may greatly break network engagement. Accordingly, we propose the collapsed k-core problem to find the vertices whose leave can lead to the smallest k-core. We prove the problem is NP-hard. Then, an efficient algorithm is proposed, which significantly reduces the number of candidate vertices to speed up computation. Comprehensive experiments on real-life social networks demonstrate effectiveness of the model and efficiency of the proposed techniques
Exploring the efficacy of Facebook groups for collective occupant learning about using their homes
The need for quality learning about how to use a home has been an issue gradually emerging from building performance evaluation (BPE) studies carried out in occupied energy efficient homes (Brown & Cole, 2009; Day & Gunderson, 2014). The BPE gap between the internal environment control as intended by designers and the actual inhabitant practices is associated with unpredicted energy consumption and poor indoor air quality (Balvers et al., 2012). The key inhabitant related causes of the ‘performance gap’ are a discrepancy between user needs and design intentions, lack of user understanding and skills to interact with the available controls and insufficient maintenance. These findings indicate that modifying tacit home use practices, adjusting them to new, more technically advanced contexts, is still not sufficiently addressed by the current learning opportunities offered by the professional actors. This paper explores how self-organised closed Facebook Groups set up independently by the residents of two UK case study urban developments have become supportive environments for such learning
The antecedents of e-learning adoption within Italian corporate universities: A comparative case study
The implementation of Information and Communication Technologies (ICT) in business education appears to be influenced by a number of organizational issues, such as culture and technological sophistication. However, extant research has had very little to say about the antecedents that shape the adoption and diffusion of ICT across companies. In order to shed light on the phenomenon under investigation, this paper presents a comparative case study between five Italian companies that have instituted a corporate university. By distinguishing companies in typical cases and deviant cases with regard to the extensive use of e-learning technologies, our findings provide some useful insights about the antecedents that make companies more or less prone to employ the new frontiers of technology in their CUs
Doctor of Philosophy
dissertationThis project is an activity-based study of American teens (13-17 years of age) and their material engagement with new media. This study documents the participants' engagement with new media in networked spaces and the everyday practices that surround their participation. Study participants were asked to orally report what they are experiencing as they experience it. Reports and on-screen activities are recorded by a laptop computer. Theoretical findings emerged from the axial coding across four code categories and suggested a leitmotiv pattern of a complex but stable relationship between interpersonal communication channels, the relative immediacy and intimacy of the channel, and the social relationship between participants. This pattern appeared to have a structuring influence on communication practices of youth in networked publics, and led to some tensions, concerns, and strategies relating to controlling the flow of information in those spaces. Overall, 10 code patterns and themes emerged to provide insight into the everyday practices of young people as they negotiate and construct meaning and identity in networked publics. The implications of the findings are discussed in the context; of the research questions. To my wife, Esther, for her love and unwavering support. To my children, who have never known a father who was not in working on a PhD. To my mother and father, who never lost confidence. My family was and is my inspiration
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