Session: Emerging Recommendation Domains

Chair: Pearl Pu
Date: Wednesday, October 26, 16:15-18:00

  • Yahoo! music recommendations: modeling music ratings with temporal dynamics and item taxonomy

    by Noam Koenigstein, Gideon Dror, Yehuda Koren

    In the past decade large scale recommendation datasets were published and extensively studied. In this work we describe a detailed analysis of a sparse, large scale dataset, specifically designed to push the envelope of recommender system models. The Yahoo! Music dataset consists of more than a million users, 600 thousand musical items and more than 250 million ratings, collected over a decade. It is characterized by three unique features: First, rated items are multi-typed, including tracks, albums, artists and genres; Second, items are arranged within a four level taxonomy, proving itself effective in coping with a severe sparsity problem that originates from the unusually large number of items (compared to, e.g., movie ratings datasets). Finally, fine resolution timestamps associated with the ratings enable a comprehensive temporal and session analysis. We further present a matrix factorization model exploiting the special characteristics of this dataset. In particular, the model incorporates a rich bias model with terms that capture information from the taxonomy of items and different temporal dynamics of music ratings. To gain additional insights of its properties, we organized the KddCup-2011 competition about this dataset. As the competition drew thousands of participants, we expect the dataset to attract considerable research activity in the future.

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  • CrimeWalker: a recommendation model for suspect investigation

    by Mohammad A. Tayebi, Mohsen Jamali, Martin Ester, Uwe Glässer, Richard Frank

    Law enforcement and intelligence agencies have long realized that analysis of co-offending networks, networks of offenders who have committed crimes together, is invaluable for crime investigation, crime reduction and prevention. Investigating crime can be a challenging and difficult task, especially in cases with many potential suspects and inconsistent witness accounts or inconsistencies between witness accounts and physical evidence. We present here a novel approach to crime suspect recommendation based on partial knowledge of offenders involved in a crime incident and a known co-offending network. To solve this problem, we propose a random walk based method for recommending the top-K potential suspects. By evaluating the proposed method on a large crime dataset for the Province of British Columbia, Canada, we show experimentally that this method outperforms baseline random walk and association rule-based methods. Additionally, results obtained for public domain data from experiments for co-author recommendation on a DBLP co-authorship network are consistent with those on the crime dataset. Compared to the crime dataset, the performance of all competitors is much better on the DBLP dataset, confirming that crime suspect recommendation is an inherently harder task.

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  • Personalized activity streams: sifting through the ‘river of news’

    by Ido Guy, Inbal Ronen, Ariel Raviv

    Activity streams have emerged as a means to syndicate updates about a user or a group of users within a social network site or a set of sites. As the flood of updates becomes highly intensive and noisy, users are faced with a “needle in a haystack” challenge when they wish to read the news most interesting to them. In this work, we study activity stream personalization as a means of coping with this challenge. We experiment with an enterprise activity stream that includes status updates and news across a variety of social media applications. We examine an entity-based user profile and a stream-based profile across three dimensions: people, terms, and places, and provide a rich set of results through a user study that combines direct rating of the objects in the profile with rating of the news items it produces.

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