Capturing User Interests for Content-based Recommendations Frank Hopfgartner frank.hopfgartner@glasgow.ac.uk 0 University of Glasgow Glasgow , UK

Nowadays, most recommender systems provide recommendations by either exploiting feedback given by similar users, referred to as collaborative filtering, or by identifying items with similar properties, referred to as content-based recommendation. Focusing on the latter, this keynote presents various examples and case studies that illustrate both strengths and weaknesses of content-based recommendation. 1http://clef-newsreel.org/

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OUTLINE campaign that allows researchers to benchmark news article recommendation algorithms in an offline [ 9 ] and an online [ 1, 5 ] setting. Given the content rich nature of news articles, as well as the large numbers of users within NewsREEL who access news online [ 8 ], the lab can serve as a training ground to improve both contentbased and collaborative filtering techniques. 2.

[1] T. Brodt and F. Hopfgartner . Shedding light on a living lab: the CLEF NewsREEL open recommendation platform . In Proceedings of IIiX'14 , pages 223 - 226 , 2014 . [2] F. Hopfgartner and J. M. Jose . Semantic user modelling for personal news video retrieval . In Proceedings of MMM'10 , pages 336 - 346 , 2010 . [3] F. Hopfgartner and J. M. Jose . Semantic user profiling techniques for personalised multimedia recommendation . Multimedia Syst ., 16 ( 4-5 ): 255 - 274 , 2010 . [4] F. Hopfgartner and J. M. Jose . An experimental evaluation of ontology-based user profiles . Multimedia Tools Appl. , 73 ( 2 ): 1029 - 1051 , 2014 . [5] F. Hopfgartner , B. Kille , A. Lommatzsch , T. Plumbaum , T. Brodt , and T. Heintz . Benchmarking news recommendations in a living lab . In Proceedings of CLEF'14 , pages 250 - 267 , 2014 . [6] F. Hopfgartner , J. Urban , R. Villa , and J. M. Jose . Simulated testing of an adaptive multimedia information retrieval system . In Proceedings of CBMI'07 , pages 328 - 335 , 2007 . [7] F. Hopfgartner , D. Vallet , M. Halvey , and J. M. Jose . Search trails using user feedback to improve video search . In Proceedings of Multimedia'08 , pages 339 - 348 , 2008 . [8] B. Kille , F. Hopfgartner , T. Brodt , and T. Heintz . The plista dataset . In Proc. of NRS'13 , pages 14 - 21 . ACM, 10 2013 . [9] B. Kille , A. Lommatzsch , R. Turrin , A. Sereny , M. Larson , T. Brodt , J. Seiler , and F. Hopfgartner . Stream-based recommendations: Online and offline evaluation as a service . In Proceedings of CLEF'15 , pages 497 - 517 , 2015 . [10] D. Vallet , F. Hopfgartner , and J. M. Jose . Use of implicit graph for recommending relevant videos: A simulated evaluation . In Proc. of ECIR'08 , pages 199 - 210 , 2008 . [11] D. Vallet , F. Hopfgartner , J. M. Jose , and P. Castells . Effects of usage-based feedback on video retrieval: A simulation-based study . ACM Trans. Inf . Syst., 29 ( 2 ): 11 , 2011 . [12] J. Yuan , F. Sivrikaya , F. Hopfgartner , A. Lommatzsch , and M. Mu . Context-aware LDA : Balancing Relevance and Diversity in TV Content Recommenders . In Proceedings of RecSysTV'15 , 2015 .