Research

For the last 5 years my research interests have been focusing on Context-Aware Collaborative Filtering Recommender Systems. During the Ph.D. studies I built the new approaches based on the state of the art methods and extended them in many ways. I introduced and evaluated a methodology supporting the full cycle of building a Context Aware Collaborative Filtering system. It includes: two phases of data acquisition, a well tuned algorithm capable of generating explanations for the recommendations, and a graphical user interface. I created more scalable and more accurate algorithms compared to those previously known in the literature. These new algorithms can be used with larger data sets, having also more contextual dimensions. The proposed methods were showed to be more accurate than any other method previously tested. Moreover, they increased user satisfaction compared with context-free methods. In my work, I also analyzed the “companion” contextual dimension as a special case. Having rich user profiles of the companion(s) we were able to build accurate recommendations for groups. We have shown that sometimes these recommendations can be even more accurate than the ones build for a single person. Especially, if the person has a small profile and he is similar to the other group members. The full thesis can accessed here. At the moment I am continuing to work in the field of Recommender Systems, Personalization and User Modeling at Telefonica I+D.

 

Selected List of Publications

Full list of publications can be found here.

Yue Shi, Alexandros Karatzoglou, Linas Baltrunas, Martha Larson, Nuria Oliver and Alan Hanjalic. CLiMF: learning to maximize reciprocal rank with collaborative less-is-more filtering ( Best paper award ). In Padraig Cunningham, Neil J Hurley, Ido Guy and Sarabjot Singh Anand (eds.). RecSys. 2012, 139-146. PDF,   BibTeX

@inproceedings{Yue12-climf,
	author = "Yue Shi and Alexandros Karatzoglou and Linas Baltrunas and Martha Larson and Nuria Oliver and Alan Hanjalic",
	bibsource = "DBLP, http://dblp.uni-trier.de",
	booktitle = "RecSys",
	date-added = "2012-09-19 13:29:13 +0000",
	date-modified = "2012-09-19 13:30:27 +0000",
	editor = "Padraig Cunningham and Neil J. Hurley and Ido Guy and Sarabjot Singh Anand",
	pages = "139-146",
	title = "CLiMF: learning to maximize reciprocal rank with collaborative less-is-more filtering ( Best paper award )",
	url = "http://baltrunas.info/papers/Shi12-climf.pdf",
	year = 2012
}

Linas Baltrunas, Bernd Ludwig, Stefan Peer and Francesco Ricci. Context relevance assessment and exploitation in mobile recommender systems. Personal and Ubiquitous Computing 16(5):507-526, 2012. PDF,   BibTeX

@article{Baltrunas12-journal,
	author = "Linas Baltrunas and Bernd Ludwig and Stefan Peer and Francesco Ricci",
	bibsource = "DBLP, http://dblp.uni-trier.de",
	date-added = "2012-08-22 10:45:20 +0000",
	date-modified = "2012-08-22 10:45:40 +0000",
	ee = "http://dx.doi.org/10.1007/s00779-011-0417-x",
	journal = "Personal and Ubiquitous Computing",
	number = 5,
	pages = "507-526",
	title = "Context relevance assessment and exploitation in mobile recommender systems",
	volume = 16,
	url = "http://baltrunas.info/papers/Baltrunas12-journal.pdf",
	year = 2012
}

Yue Shi, Alexandros Karatzoglou, Linas Baltrunas, Martha Larson, Alan Hanjalic and Nuria Oliver. TFMAP: optimizing MAP for top-n context-aware recommendation. In William R Hersh, Jamie Callan, Yoelle Maarek and Mark Sanderson (eds.). The 35th International ACM SIGIR conference on research and development in Information Retrieval, SIGIR '12, Portland, OR, USA, August 12-16, 2012. 2012, 155-164. PDF,   BibTeX

@inproceedings{Shi12-tfmap,
	author = "Yue Shi and Alexandros Karatzoglou and Linas Baltrunas and Martha Larson and Alan Hanjalic and Nuria Oliver",
	bibsource = "DBLP, http://dblp.uni-trier.de",
	booktitle = "The 35th International ACM SIGIR conference on research and development in Information Retrieval, SIGIR '12, Portland, OR, USA, August 12-16, 2012",
	date-added = "2012-08-22 10:44:01 +0000",
	date-modified = "2012-08-22 10:51:11 +0000",
	editor = "William R. Hersh and Jamie Callan and Yoelle Maarek and Mark Sanderson",
	ee = "http://doi.acm.org/10.1145/2348283.2348308",
	pages = "155-164",
	publisher = "ACM",
	title = "TFMAP: optimizing MAP for top-n context-aware recommendation",
	url = "http://baltrunas.info/papers/Shi12-tfmap.pdf",
	year = 2012
}

Alexandros Karatzoglou, Xavier Amatriain, Linas Baltrunas and Nuria Oliver. Multiverse recommendation: n-dimensional tensor factorization for context-aware collaborative filtering. In Xavier Amatriain, Marc Torrens, Paul Resnick and Markus Zanker (eds.). RecSys. 2010, 79-86. PDF,   BibTeX

@inproceedings{Karatzoglou10-tf,
	author = "Alexandros Karatzoglou and Xavier Amatriain and Linas Baltrunas and Nuria Oliver",
	bibsource = "DBLP, http://dblp.uni-trier.de",
	booktitle = "RecSys",
	date-added = "2012-08-22 15:21:12 +0000",
	date-modified = "2012-08-22 15:22:18 +0000",
	editor = "Xavier Amatriain and Marc Torrens and Paul Resnick and Markus Zanker",
	pages = "79-86",
	publisher = "ACM",
	title = "Multiverse recommendation: n-dimensional tensor factorization for context-aware collaborative filtering",
	url = "http://baltrunas.info/papers/Karatzoglou10-tf.pdf",
	year = 2010
}

Linas Baltrunas, Tadas Makcinskas and Francesco Ricci. Group recommendations with rank aggregation and collaborative filtering. In Xavier Amatriain, Marc Torrens, Paul Resnick and Markus Zanker (eds.). Proceedings of the 2010 ACM Conference on Recommender Systems, RecSys 2010, Barcelona, Spain, September 26-30. 2010, 119-126. PDF,   BibTeX

@inproceedings{Baltrunas10-group,
	author = "Linas Baltrunas and Tadas Makcinskas and Francesco Ricci",
	bibsource = "DBLP, http://dblp.uni-trier.de",
	booktitle = "Proceedings of the 2010 ACM Conference on Recommender Systems, RecSys 2010, Barcelona, Spain, September 26-30",
	crossref = "DBLP:conf/recsys/2010",
	date-added = "2012-08-22 15:23:41 +0000",
	date-modified = "2012-08-22 15:24:36 +0000",
	editor = "Xavier Amatriain and Marc Torrens and Paul Resnick and Markus Zanker",
	pages = "119-126",
	title = "Group recommendations with rank aggregation and collaborative filtering",
	url = "http://baltrunas.info/papers/Baltrunas10-group.pdf",
	year = 2010
}