Information technology and social cohesion : a tale of two villages

Acknowledgements This research was made possible by a grant from the EPSRC “Dot.Rural Digital Economy Hub” (EP/G066051/1) at the University of Aberdeen and EPSRC Communities and Culture Network+ (EP/K003585/1).Peer reviewedPostprin

Embedding Graphs under Centrality Constraints for Network Visualization

Visual rendering of graphs is a key task in the mapping of complex network data. Although most graph drawing algorithms emphasize aesthetic appeal, certain applications such as travel-time maps place more importance on visualization of structural network properties. The present paper advocates two graph embedding approaches with centrality considerations to comply with node hierarchy. The problem is formulated first as one of constrained multi-dimensional scaling (MDS), and it is solved via block coordinate descent iterations with successive approximations and guaranteed convergence to a KKT point. In addition, a regularization term enforcing graph smoothness is incorporated with the goal of reducing edge crossings. A second approach leverages the locally-linear embedding (LLE) algorithm which assumes that the graph encodes data sampled from a low-dimensional manifold. Closed-form solutions to the resulting centrality-constrained optimization problems are determined yielding meaningful embeddings. Experimental results demonstrate the efficacy of both approaches, especially for visualizing large networks on the order of thousands of nodes.Comment: Submitted to IEEE Transactions on Visualization and Computer Graphic

Cloudworks: social networking for learning design

Why do some social networking services work and others fail? Can we apply the best of Web 2.0 principles to an educational context? More specifically can we use this as a means of shifting teaching practice to a culture of sharing learning ideas and designs? Can we harness the potential of technologies to create more engaging learning experiences for students? These are the key questions this paper addresses. We describe how we are using the concept of 'object-orientated social networking' to underpin the creation of a social networking tool, Cloudworks, for sharing learning ideas and designs