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Tech Report kmi-97-03 Abstract


Efficient Parameter Learning in Bayesian Networks from Incomplete Databases
Techreport ID: kmi-97-03
Date: 1997
Author(s): Marco Ramoni and Paola Sebastiani
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Current methods to learn conditional probabilities from incomplete databases use a common strategy: they complete the database by inferring somehow the missing data from the available information and then learn from the completed database. This paper introduces a new method - called bound and collapse (BC) - which does not follow this strategy. BC starts by bounding the set of estimates consistent with the available information and then collapses the resulting set to a point estimate via a convex combination of the extreme points, with weights depending on the assumed pattern of missing data. Experiments comparing c to the Gibbs Samplings are also provided. 1. Knowledge Media Institute, The Open University. 2. Department of Actuarial Science and Statistics, City University.
 
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Social Software is...


Social Software
Social Software can be thought of as "software which extends, or derives added value from, human social behaviour - message boards, musical taste-sharing, photo-sharing, instant messaging, mailing lists, social networking."

Interacting with other people not only forms the core of human social and psychological experience, but also lies at the centre of what makes the internet such a rich, powerful and exciting collection of knowledge media. We are especially interested in what happens when such interactions take place on a very large scale -- not only because we work regularly with tens of thousands of distance learners at the Open University, but also because it is evident that being part of a crowd in real life possesses a certain 'buzz' of its own, and poses a natural challenge. Different nuances emerge in different user contexts, so we choose to investigate the contexts of work, learning and play to better understand the trade-offs involved in designing effective large-scale social software for multiple purposes.