Publications | Information Retrieval Group

2020

R. Cañamares, P. Castells. On Target Item Sampling in Offline Recommender System Evaluation. 14th ACM Conference on Recommender Systems (RecSys 2020). Virtual Event, Brazil, September 2020, pp. 259–268.

(BibTeX | Tags: recommender systems, evaluation, bias, discriminative power)

R. Cañamares, P. Castells, A. Moffat. Offline Evaluation Options for Recommender Systems. Information Retrieval 23(4), August 2020, pp. 387-410.

(BibTeX | Tags: recommender systems, evaluation)

D. Valcarce, A. Bellogín, J. Parapar, P. Castells. Assessing ranking metrics in top-N recommendation. Information Retrieval 23(4), August 2020, pp. 411-448.

(BibTeX | Tags: recommender systems, metrics, evaluation)

E. Mena-Maldonado, R. Cañamares, P. Castells, Y. Ren, M. Sanderson. Agreement and Disagreement between True and False-Positive Metrics in Recommender Systems Evaluation. 43rd International ACM SIGIR Conference on Research and Development in Information Retrieval (SIGIR 2020). Virtual Event, China, July 2020, pp. 841-850.

(BibTeX | Tags: recommender systems, metrics, evaluation, popularity, bias, non-random missing data, false positive)

2019

J. Sanz-Cruzado, P. Castells. Beyond Accuracy in Link Prediction. 3rd Workshop on Social Media for Personalization And Search (SoMePeAS 2019) at the 41st European Conference on Information Retrieval (ECIR 2019). Cologne, Germany, April 2019.

(BibTeX | Tags: novelty, diversity, recommender systems, evaluation, social networks, link prediction, contact recommendation)

2018

J. Sanz-Cruzado, P. Castells. Contact Recommendations in Social Networks. In S. Berkovsky, I. Cantador, D. Tikk (Eds.): Collaborative Recommendations: Algorithms, Practical Challenges and Applications. World Scientific Publishing, November 2018, ISBN: 978-981-3275-35-5, pp. 519-569.

(BibTeX | Tags: recommender systems, evaluation, social networks, link prediction, contact recommendation)

P. Castells, R. Cañamares. Characterization of Fair Experiments for Recommender System Evaluation – A Formal Analysis. Workshop on Offline Evaluation for Recommender Systems (REVEAL 2018) at the 12th ACM Conference on Recommender Systems (RecSys 2018). Vancouver, Canada, October 2018.
Poster

(BibTeX | Tags: recommender systems, evaluation, popularity, information retrieval theory, bias, non-random missing data)

J. Sanz-Cruzado, P. Castells. Enhancing Structural Diversity in Social Networks by Recommending Weak Ties. 12th ACM Conference on Recommender Systems (RecSys 2018). Vancouver, Canada, October 2018, pp. 233-241.
Slides | Poster

(BibTeX | Tags: novelty, diversity, recommender systems, evaluation, social networks, contact recommendation)

D. Valcarce, A. Bellogín, J. Parapar, P. Castells. On the Robustness and Discriminative Power of IR Metrics for Top-N Recommendation. 12th ACM Conference on Recommender Systems (RecSys 2018). Vancouver, Canada, October 2018, pp. 260-268.

(BibTeX | Tags: recommender systems, metrics, evaluation)

R. Cañamares, P. Castells. Should I Follow the Crowd? A Probabilistic Analysis of the Effectiveness of Popularity in Recommender Systems. 41st Annual International ACM SIGIR Conference on Research and Development in Information Retrieval (SIGIR 2018). Ann Arbor, Michigan, USA, July 2018, pp. 415-424 — best paper award.
Slides

(BibTeX | Tags: recommender systems, evaluation, information retrieval, popularity, information retrieval theory, bias, non-random missing data)

R. Cañamares, P. Castells. From the PRP to the Low Prior Discovery Recall Principle for Recommender Systems. 41st Annual International ACM SIGIR Conference on Research and Development in Information Retrieval (SIGIR 2018). Ann Arbor, Michigan, USA. July 2018, pp. 1081-1084.
Poster

(BibTeX | Tags: novelty, recommender systems, metrics, evaluation, information retrieval, popularity, information retrieval theory)

J. Sanz-Cruzado, S. M. Pepa, P. Castells. Structural Novelty and Diversity in Link Prediction. 9th International Workshop on Modeling Social Media (MSM 2018) at The Web Conference (TheWebConf 2018). Lyon, France, April 2018.

(BibTeX | Tags: novelty, diversity, recommender systems, evaluation, social networks, link prediction)

P. Sánchez, A. Bellogín. Time-Aware Novelty Metrics for Recommender Systems. 40th European Conference on Information Retrieval (ECIR 2018). Grenoble, France, Springer, March 2018, ISBN: 978-3-319-76941-7, pp. 357-370.

(BibTeX | Tags: novelty, recommender systems, evaluation)

2017

R. Mesas, A. Bellogín. Evaluating Decision-Aware Recommender Systems. 11th ACM Conference on Recommender Systems (RecSys 2017). Como, Italy, August 2017, ISBN: 978-1-4503-4652-8, pp. 74-78.

(BibTeX | Tags: recommender systems, evaluation)

R. Cañamares, P. Castells. On the Optimal Non-Personalized Recommendation: From the PRP to the Discovery False Negative Principle. ACM SIGIR 2017 Workshop on Axiomatic Thinking for Information Retrieval and Related Tasks (ATIR 2017). Tokyo, Japan, August 2017.

(BibTeX | Tags: recommender systems, evaluation, popularity, information retrieval theory, probability ranking principle)

R. Cañamares, P. Castells. A Probabilistic Reformulation of Memory-Based Collaborative Filtering – Implications on Popularity Biases. 40th Annual International ACM SIGIR Conference on Research and Development in Information Retrieval (SIGIR 2017). Tokyo, Japan, August 2017, pp. 215-224.
Slides

(BibTeX | Tags: evaluation, collaborative filtering, knn, popularity, probabilistic models)

A. Bellogín, P. Castells, I. Cantador. Statistical Biases in Information Retrieval Metrics for Recommender Systems. Information Retrieval 20(6), July 2017, pp. 606-634.

(BibTeX | Tags: recommender systems, evaluation, popularity)

2015

P. Castells, N. J. Hurley, S. Vargas. Novelty and Diversity in Recommender Systems. In Francesco Ricci, Lior Rokach, Bracha Shapira (Eds.): Recommender Systems Handbook, 2nd edition. Springer, 2015, ISBN: 978-1-4899-7637-6, pp. 881-918.

(BibTeX | Tags: novelty, diversity, recommender systems, evaluation, information retrieval)

2014

S. Vargas, L. Baltrunas, A. Karatzoglou, P. Castells. Coverage, Redundancy and Size-Awareness in Genre Diversity for Recommender Systems. 8th ACM Conference on Recommender Systems (RecSys 2014). Foster City, CA, USA, October 2014, pp. 209-216.
Slides | Poster

(BibTeX | Tags: novelty, diversity, recommender systems, evaluation)

R. Cañamares, P. Castells. Exploring social network effects on popularity biases in recommender systems. 6th Workshop on Recommender Systems and the Social Web (RSWeb 2014) at the 8th ACM Conference on Recommender Systems (RecSys 2014). Foster City, CA, USA, October 2014.

(BibTeX | Tags: recommender systems, evaluation, social networks)

2013

A. Bellogín, I. Cantador, P. Castells, F. Díez. Exploiting Social Networks in Recommendation: a Multi-Domain Comparison. 13th Dutch-Belgian Information Retrieval Workshop (DIR 2013). Delft, Netherlands, April 2013.

(BibTeX | Tags: recommender systems, evaluation, collaborative filtering, social networks, context)

A. Bellogín, I. Cantador, P. Castells. A Comparative Study of Heterogeneous Item Recommendations in Social Systems. Information Sciences 221(1), February 2013, pp. 142-169.

(BibTeX | Tags: novelty, diversity, recommender systems, evaluation, collaborative filtering, social networks)

2012

S. Vargas, P. Castells, D. Vallet. On the Suitability of Intent Spaces for IR Diversification. International Workshop on Diversity in Document Retrieval (DDR 2012) at the 5th ACM International Conference on Web Search and Data Mining (WSDM 2012). Seattle, Washington, USA, February 2012.

(BibTeX | Tags: diversity, evaluation, query aspect, information retrieval)

2011

A. Bellogín, P. Castells, I. Cantador. Precision-Oriented Evaluation of Recommender Systems: An Algorithmic Comparison. 5th ACM Conference on Recommender Systems (RecSys 2011). Chicago, Illinois, October 2011, pp. 333-336.

(BibTeX | Tags: recommender systems, metrics, evaluation, experimental methodology)

S. Vargas, P. Castells. Rank and Relevance in Novelty and Diversity Metrics for Recommender Systems. 5th ACM Conference on Recommender Systems (RecSys 2011). Chicago, Illinois, October 2011, pp. 109-116.
Slides

(BibTeX | Tags: novelty, diversity, recommender systems, metrics, evaluation)

P. G. Campos, F. Díez, M. Sánchez-Montañés. Towards a More Realistic Evaluation: Testing the Ability to Predict Future Tastes of Matrix Factorization-based Recommenders. 5th ACM Conference on Recommender Systems (RecSys-2011). October 2011, pp. 309-312.
Poster

(BibTeX | Tags: recommender systems, evaluation, time)

S. Vargas, P. Castells, D. Vallet. Intent-Oriented Diversity in Recommender Systems. 34th Annual International ACM SIGIR Conference on Research and Development in Information Retrieval (SIGIR 2011). Beijing, China, July 2011, pp. 1211-1212.
Poster

(BibTeX | Tags: diversity, recommender systems, metrics, evaluation, information retrieval)

P. Castells, S. Vargas, J. Wang. Novelty and Diversity Metrics for Recommender Systems: Choice, Discovery and Relevance. International Workshop on Diversity in Document Retrieval (DDR 2011) at the 33rd European Conference on Information Retrieval (ECIR 2011). Dublin, Ireland, April 2011.

(BibTeX | Tags: novelty, diversity, recommender systems, metrics, evaluation, information retrieval)

2009

M. Fernández, V. López, M. Sabou, V. Uren, D. Vallet, E. Motta, P. Castells. Using TREC for cross-comparison between classic IR and ontology-based search models at a Web scale. Workshop on Semantic Search (SemSearch 2009), at the 18th International World Wide Web Conference (WWW 2009). Madrid, Spain, April 2009.

(BibTeX | Tags: evaluation, expermiental methodology, semantic search, information retrieval)

2008

M. Fernández, V. López, M. Sabou, V. Uren, D. Vallet, E. Motta, P. Castells. Semantic Search meets the Web. 2nd IEEE International Conference on Semantic Computing (ICSC 2008). Santa Clara, CA, USA, August 2008.

(BibTeX | Tags: evaluation, semantic search, information retrieval)