Publications | Pablo Castells

2021

E. Mena-Maldonado, R. Cañamares, P. Castells, Y. Ren, M. Sanderson. Popularity Bias in False-Positive Metrics for Recommender Systems Evaluation. ACM Transactions in Information Systems, 2021, pp. in press.

(BibTeX | Tags: recommender systems, evaluation, bias, false positives)

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)

J. Sanz-Cruzado, P. Castells, C. Macdonald, I. Ounis. Effective Contact Recommendation in Social Networks by Adaptation of Information Retrieval Models. Information Processing & Management 57(5), September 2020.

(BibTeX | Tags: recommender systems, information retrieval models, social networks, contact recommendation, learning to rank)

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)

J. Sanz-Cruzado, C. Macdonald, I. Ounis, P. Castells. Axiomatic Analysis of Contact Recommendation Methods in Social Networks: an IR perspective. 42th European Conference on Information Retrieval (ECIR 2020), Springer Verlag Lecture Notes in Computer Science, Vol. 12035. Lisbon, Portugal, April 2020, ISBN: 978-3-030-45439-5, pp. 175-90.

(BibTeX | Tags: recommender systems, social networks, information retrieval, contact recommendation, axiomatic information retrieval)

2019

J. Sanz-Cruzado, P. Castells, E. López. A Simple Multi-Armed Nearest-Neighbor Bandit for Interactive Recommendation. 13th ACM Conference on Recommender Systems (RecSys 2019). Copenhagen, Denmark, September 2019, pp. 358-362.
Poster

(BibTeX | Tags: recommender systems, knn, multi-armed bandits, thompson sampling, interactive recommendation)

R. Cañamares, M. Redondo, P. Castells. Multi-Armed Recommender System Bandit Ensembles. 13th ACM Conference on Recommender Systems (RecSys 2019). Copenhagen, Denmark, September 2019, pp. 432-436.
Poster

(BibTeX | Tags: recommender systems, multi-armed bandits, ensembles, hybrid recommender systems, feedback loop, interactive re)

J. Sanz-Cruzado, P. Castells. Information Retrieval Models for Contact Recommendation in Social Networks. 41st European Conference on Information Retrieval (ECIR 2019), Springer Verlag Lecture Notes in Computer Science, Vol. 11437. Cologne, Germany, April 2019, ISBN: 978-3-030-15711-1, pp. 148-163.
Slides

(BibTeX | Tags: recommender systems, information retrieval models, social networks, information retrieval, contact recommendation)

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)

2017

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)

S. Vargas, P. Castells. Improving Sales Diversity by Recommending Users to Items. 8th ACM Conference on Recommender Systems (RecSys 2014). Foster City, CA, USA, October 2014, pp. 145-152.
Slides | Poster

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

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)

A. Bellogín, P. Castells, I. Cantador. Neighbor Selection and Weighting in User-Based Collaborative Filtering: A Performance Prediction Approach. ACM Transactions on the Web 8(2), March 2014.

(BibTeX | Tags: recommender systems, collaborative filtering, performance prediction, information retrieval)

2013

A. Bellogín, J. Wang, P. Castells. Bridging Memory-Based Collaborative Filtering and Text Retrieval. Information Retrieval 16(6), December 2013, pp. 697-724.

(BibTeX | Tags: recommender systems, collaborative filtering, information retrieval models, information retrieval)

A. Bellogín, J. Parapar, P. Castells. Probabilistic Collaborative Filtering with Negative Cross Entropy. 7th ACM Conference on Recommender Systems (RecSys 2013). Hong Kong, China, October 2013, pp. 387-390.

(BibTeX | Tags: recommender systems, collaborative filtering, information retrieval models, information retrieval)

J. Parapar, A. Bellogín, P. Castells, A. Barreiro. Relevance-Based Language Modelling for Recommender Systems. Information Processing & Management 49(4), July 2013.

(BibTeX | Tags: recommender systems, collaborative filtering, information retrieval models, information retrieval)

S. Vargas, P. Castells. Exploiting the Diversity of User Preferences for Recommendation. 10th International Conference in the RIAO series (OAIR 2013). Lisbon, Portugal, May 2013.
Slides

(BibTeX | Tags: diversity, recommender systems, web services, user profile)

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, F. Díez, P. Castells, E. Chavarriaga. An Empirical Comparison of Social, Collaborative Filtering, and Hybrid Recommenders. ACM Transactions on Intelligent Systems and Technology 4(1), special issue on Context-Aware Movie Recommendations, February 2013.

(BibTeX | Tags: recommender systems, social networks, hybrid recommendation)

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. Explicit Relevance Models in Intent-Oriented Information Retrieval Diversification. 35th Annual International ACM SIGIR Conference on Research and Development in Information Retrieval (SIGIR 2012). Portland, OR, USA, August 2012, pp. 75-84.
Slides

(BibTeX | Tags: diversity, information retrieval models, personalization, information retrieval)

D. Vallet, P. Castells. Personalized Diversification of Search Results. 35th Annual International ACM SIGIR Conference on Research and Development in Information Retrieval (SIGIR 2012). Portland, OR, USA, August 2012, pp. 841-850.

(BibTeX | Tags: diversity, information retrieval models, personalization, information retrieval)

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)

I. Cantador, P. Castells. Group Recommender Systems: New Perspectives in the Social Web. In J. J. Pazos Arias, A. Fernández Vilas, R. P. Díaz Redondo (Eds.): Recommender Systems for the Social Web. Springer Verlag, Intelligent Systems Reference Library, Vol. 32, 2012, ISBN: 978-3-642-25693-6, pp. 139-157.

(BibTeX | Tags: recommender systems, social web, group recommendation)

2011

M. Fernández, I. Cantador, V. López, D. Vallet, P. Castells, E. Motta. Semantically enhanced Information Retrieval: an ontology-based approach. Journal of Web Semantics 9(4), special issue on Semantic Search, December 2011, pp. 434-452.

(BibTeX | Tags: semantic search, information retrieval)

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)

A. Bellogín, J. Wang, P. Castells. Structured Collaborative Filtering. 20th ACM International Conference on Information and Knowledge Management (CIKM 2011). Glasgow, UK, October 2011, pp. 2257-2260.

(BibTeX | Tags: recommender systems, collaborative filtering, information retrieval models, information retrieval)

A. Bellogín, P. Castells, I. Cantador. Predicting the Performance of Recommender Systems: An Information Theoretic Approach. 3rd International Conference on the Theory of Information Retrieval (ICTIR 2011) - Springer Verlag Lecture Notes in Computer Science, Vol. 6931. Bertinoro, Italy, September 2011, ISBN: 978-3-642-23317-3, pp. 27-39.

(BibTeX | Tags: recommender systems, performance prediction, information retrieval)

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)

D. Vallet, P. Castells. On Diversifying and Personalizing Web Search. 34th Annual International ACM SIGIR Conference on Research and Development in Information Retrieval (SIGIR 2011). Beijing, China, July 2011, pp. 1157-1158.

(BibTeX | Tags: diversity, personalization, web search, information retrieval)

A. Bellogín, P. Castells, I. Cantador. Self-adjusting Hybrid Recommenders Based on Social Network Analysis. 34th Annual International ACM SIGIR Conference on Research and Development in Information Retrieval (SIGIR 2011). Beijing, China, July 2011, pp. 1147-1148.

(BibTeX | Tags: recommender systems, performance prediction, social networks, hybrid recommendation)

I. Cantador, P. Castells. Extracting Multilayered Communities of Interest from Semantic User Profiles: Application to Group Modeling and Hybrid Recommendations. Computers in Human Behavior 27(4), special issue on Social and Humanistic Computing for the Knowledge Society, July 2011, pp. 1321-1336.

(BibTeX | Tags: recommender systems, hybrid recommendation, semantics, community detection, group recommendation)

D. Vallet, M. Halvey, J. Jose, P. Castells. Applying Soft Links to Diversify Video Recommendations. 9th International Workshop on Content-Based Multimedia Indexing (CBMI 2011). Madrid, Spain, June 2011.

(BibTeX | Tags: diversity, soft links, video recommendation, information retrieval, multimedia 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)

A. Bellogín, J. Wang, P. Castells. Text Retrieval Methods for Item Ranking in Collaborative Filtering. 33rd European Conference on Information Retrieval (ECIR 2011), Springer Verlag Lecture Notes in Computer Science, Vol. 6611. Dublin, Ireland, April 2011, ISBN: 978-3642201608, pp. 301-306.

(BibTeX | Tags: collaborative filtering, information retrieval models, information retrieval)

D. Vallet, F. Hopfgartner, J. M. Jose, P. Castells. Effects of Usage-Based Feedback on Video Retrieval: A Simulation-Based Study. ACM Transactions on Information Systems 29(2), April 2011.

(BibTeX | Tags: implicit feedback, recommendation, multimedia retrieval)

A. Bellogín, I. Cantador, P. Castells, Á. Ortigosa. Discerning Relevant Model Features in a Content-based Collaborative Recommender System. In J. Fürnkranz, E. Hüllermeier (Eds.): Preference Learning. Springer Verlag, 2011, ISBN: 978-3-642-14124-9, pp. 429-456.

(BibTeX | Tags: recommender systems, collaborative filtering, content-based recommendation)

I. Cantador, P. Castells, A. Bellogín. An Enhanced Semantic Layer for Hybrid Recommender Systems: Application to News Recommendation. International Journal on Semantic Web and Information Systems 7(1), 2011, pp. 44-78.

(BibTeX | Tags: recommender systems, hybrid recommendation, semantics, news retrieval)

2010

A. Bellogín, P. Castells. A Performance Prediction Approach to Enhance Collaborative Filtering Performance. 32nd European Conference on Information Retrieval (ECIR 2010), Springer Verlag Lecture Notes in Computer Science, Vol. 5993. Milton Keynes, UK, May 2010, ISBN: 978-3642122743, pp. 382-393.

(BibTeX | Tags: recommender systems, collaborative filtering, performance prediction)

2009

A. Bellogín, P. Castells. Predicting Neighbor Goodness in Collaborative Filtering. 8th International Conference on Flexible Query Answering Systems (FQAS 2009), Springer Verlag Lecture Notes in Computer Science, Vol. 5822. Roskilde, Denmark, October 2009, ISBN: 978-3-642-04956-9, pp. 605-616.

(BibTeX | Tags: recommender systems, collaborative filtering, performance prediction)

I. Cantador, P. Castells. Semantic Contextualisation in a News Recommender Systems. Workshop on Context-Aware Recommender Systems (CARS 2009) at the 3rd ACM Conference on Recommender Systems (RecSys 2009). New York, NY, USA, October 2009.

(BibTeX | Tags: recommender systems, context, news retrieval)

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

I. Cantador, A. Bellogín, P. Castells. Ontology-based Personalised and Context-aware Recommendations of News Items. IEEE/WIC/ACM International Conference on Web Intelligence (WI 2008). Sydney, Australia, December 2008.

(BibTeX | Tags: recommender systems, context, semantics, news retrieval)

A. Bellogín, I. Cantador, P. Castells, A. Ortigosa. Discovering Relevant Preferences in a Personalised Recommender System using Machine Learning Techniques. Preference Learning Workshop (PL 2008), at the 8th European Conference on Machine Learning and Principles and Practice of Knowledge Discovery in Databases (ECML PKDD 2008). Antwerp, Belgium, September 2008, pp. 82-96.

(BibTeX | Tags: recommender systems, machine learning)

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)

I. Cantador, A. Bellogín, P. Castells. News@hand: A Semantic Web Approach to Recommending News. 5th International Conference on Adaptative Hypermedia (AH 2008), Springer Verlag Lecture Notes in Computer Science, Vol. 5149. Hannover, Germany, July 2008, ISBN: 978-3-540-70984-8, pp. 279-283.

(BibTeX | Tags: recommender systems, semantics, news retrieval)

I. Cantador, M. Szomszor, H. Alani, M. Fernández, P. Castells. Enriching Ontological User Profiles with Tagging History for Multi-Domain Recommendations. 1st International Workshop on Collective Semantics: Collective Intelligence and the Semantic Web (CISWeb 2008), at the 5th European Semantic Web Conference (ESWC 2008). Tenerife, Spain, June 2008, pp. 5-19.

(BibTeX | Tags: recommender systems, personalization, semantics)

I. Cantador, A. Bellogín, P. Castells. A Multilayer Ontology-based Hybrid Recommendation Model. AI Communications 21(2-3), special issue on Recommender Systems, April 2008, pp. 203-210.

(BibTeX | Tags: recommender systems, hybrid recommendation, semantics)

Ph. Mylonas, D. Vallet, P. Castells, M. Fernández, and Y. Avrithis. Personalized information retrieval based on context and ontological knowledge. Knowledge Engineering Review 23(1), special issue on Contexts and Ontologies, March 2008, pp. 73-100.

(BibTeX | Tags: personalization, context, information retrieval, semantics)

C. Dolbear, P. Hobson, D. Vallet, M. Fernández, I. Cantador, P. Castells. Personalised Multimedia Summaries. In Y. Kompatsiaris, P. Hobson (Eds.): Semantic Multimedia and Ontologies. Springer Verlag, March 2008, ISBN: 978-1-84800-075-9, pp. 165-184.

(BibTeX | Tags: personalization, information retrieval, automatic summarization, multimedia retrieval)

I. Cantador, M. Fernández, D. Vallet, P. Castells, J. Picault, M. Ribière. A Multi-Purpose Ontology-Based Approach for Personalised Content Filtering and Retrieval. In M. Wallace, M. Angelides, Ph. Mylonas (Eds.): Advances in Semantic Media Adaptation and Personalization. Springer Verlag Studies in Computational Intelligence, Vol. 93, February 2008, ISBN: 978-3-540-76359-8, pp. 25-52.

(BibTeX | Tags: information retrieval models, personalization, information retrieval, semantics)

R. Lara, M. Corella, P. Castells. A flexible model for the location of services. International Journal of Electronic Commerce 12(2), special issue on Semantic Matchmaking and Resource Retrieval, January 2008, pp. 11-40.

(BibTeX | Tags: web services)

2007

J. Tejedor, R. García, M. Fernández, F. J. López, F. Perdrix, J. A. Macías, R. M. Gil, M. Oliva, D. Moya, J. Colás, P. Castells. Ontology-Based Retrieval of Human Speech. 6th International Workshop on Web Semantics (WebS 2007) at the 18th International Conference on Database and Expert Systems Applications (DEXA 2007). Regensburg, Germany, September 2007.

(BibTeX | Tags: information retrieval, semantics, speech recognition)

J. A. Macías, P. Castells. Providing end-user facilities to simplify ontology-driven web application authoring. Interacting with Computers 19(4), July 2007, pp. 563-585.

(BibTeX | Tags: semantics, hci)

M. Ruiz-Casado, E. Alfonseca, P. Castells. Automatising the Learning of Lexical Patterns: an Application to the Enrichment of WordNet by Extracting Semantic Relationships from Wikipedia. Data and Knowledge Engineering 61(3), June 2007, pp. 484-499.

(BibTeX | Tags: nlp, semantics, relation extraction, information extraction)

I. Cantador, P. Castells, A. Bellogín. Modelling Ontology-based Multilayered Communities of Interest for Hybrid Recommendations. 1st Workshop on Adaptation and Personalization in Social Systems: Groups, Teams, Communities (SociUM 2007) at the 11th International Conference on User Modeling (UM 2007). Corfu, Greece, June 2007.

(BibTeX | Tags: recommender systems, hybrid recommendation, semantics)

I. Cantador, M. Fernández, P. Castells. Improving Ontology Recommendation and Reuse in WebCORE by Collaborative Assessments. Workshop on Social and Collaborative Construction of Structured Knowledge at the 16th International World Wide Web Conference (WWW 2007). Banff, Canada, May 2007.

(BibTeX | Tags: recommender systems, collaborative filtering, semantics, collaborative systems)

D. Vallet, P. Castells, M. Fernández, P. Mylonas, Y. Avrithis. Personalized Content Retrieval in Context Using Ontological Knowledge. IEEE Transactions on Circuits and Systems for Video Technology 17(3), special issue on the convergence of knowledge engineering, semantics and signal processing in audiovisual information retrieval, March 2007, pp. 336-346.

(BibTeX | Tags: personalization, context, information retrieval, semantics)

P. Castells, M. Fernández, D. Vallet. An Adaptation of the Vector-Space Model for Ontology-Based Information Retrieval. IEEE Transactions on Knowledge and Data Engineering 19(2), special issue on Knowledge and Data Engineering in the Semantic Web Era, February 2007, pp. 261-272.

(BibTeX | Tags: semantic search, information retrieval)

R. Lara, I. Cantador, P. Castells. Semantic Web Technologies for the Financial Domain. In J. Cardoso, M. Hepp, M. D. Lytras (Eds.): Real-world Applications of Semantic Web Technology and Ontologies. Springer Verlag, 2007, ISSN: 0387485309, pp. 41-74.

(BibTeX | Tags: semantics, finance)

2006

D. Vallet, I. Cantador, M. Fernández, P. Castells. A Multi-Purpose Ontology-Based Approach for Personalized Content Filtering and Retrieval. 1st International Workshop on Semantic Media Adaptation and Personalization (SMAP 2006). Athens, Greece, December 2006.

(BibTeX | Tags: personalization, information retrieval, semantics)

R. Lara, I. Cantador, P. Castells. XBRL taxonomies and OWL ontologies for investment funds. 1st International Workshop on Ontologizing Industrial Standards (OIS 2006), at the 25th International Conference on Conceptual Modeling (ER 2006). Springer Verlag Lecture Notes in Computer Science, Vo. Tucson, AZ, USA, November 2006, ISSN: 978-3-540-47703-7, pp. 271-280.

(BibTeX | Tags: semantics, finance, xbrl)

I. Cantador, P. Castells. Multilayered Semantic Social Network Modeling by Ontology-Based User Profiles Clustering: Application to Collaborative Filtering. 15th International Conference on Knowledge Engineering and Knowledge Management (EKAW 2006). Springer Verlag Lecture Notes in Computer Science, Vol. 4248. Podebrady, Czech Republic, October 2006, ISSN: 3-540-46363-1, pp. 334-349.

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

M. A. Corella, P. Castells. A Heuristic Approach to Semantic Web Services Classification. 10th International Conference on Knowledge-Based & Intelligent Information & Engineering Systems (KES 2006). Springer Verlag Lecture Notes in Computer Science, Vol. 4253. Bournemouth, UK, October 2006, ISSN: 978-3-540-46542-3, pp. 598-605.

(BibTeX | Tags: semantics, web services)

J. M. Fuentes, J. E. López de Vergara, P. Castells. An Ontology-Based Approach to the Description and Execution of Composite Network Management Processes for Network Monitoring. 17th IFIP/IEEE International Workshop on Distributed Systems: Operations and Management Large Scale Management (DSOM 2006). Springer Verlag Lecture Notes in Computer Science, Vol. 4269. Dublin, Ireland, October 2006, ISSN: 978-3-540-47659-7, pp. 86-97.

(BibTeX | Tags: semantics, network management, network monitoring)

R. Lara, M. A. Corella, P. Castells. A Flexible Model for Web Service Discovery. 1st International Workshop on Semantic Matchmaking and Resource Retrieval: Issues and Perspectives (SMR 2006) at the 32nd International Conference on Very Large Data Bases (VLDB 2006). Seoul, Korea, September 2006.

(BibTeX | Tags: web services, web service discovery)

M. A. Corella, P. Castells. Semantic-based Taxonomic Categorization of Web Services. 1st International Workshop on Semantic Matchmaking and Resource Retrieval: Issues and Perspectives (SMR 2006) at the 32nd International Conference on Very Large Data Bases (VLDB 2006). Seoul, Korea, September 2006.

(BibTeX | Tags: semantics, web services)

M. A. Corella, P. Castells. Semi-Automatic Semantic-Based Web Service Classification. Int. Workshop on Advances in Semantics for Web Services (semantics4ws 2006) at the 4th Int. Conf. on Business Process Mangement (BPM 2006). Springer Verlag Lecture Notes in Computer Science, Vol. 4013. Vienna, Austria, September 2006, ISSN: 978-3-540-38444-1, pp. 459-470.

(BibTeX | Tags: semantics, web services)

M. Fernández, D. Vallet, P. Castells. Using Historical Data to Enhance Rank Aggregation. 29th Annual International ACM Conference on Research and Development in Information Retrieval (SIGIR 2006). Seattle, WA, USA, August 2006, pp. 643-644.

(BibTeX | Tags: rank fusion, information retrieval, rank aggregation, metasearch)

D. Vallet, M. Fernández, P. Castells, P. Mylonas, Y. Avrithis. A contextual personalization approach based on ontological knowledge. International Workshop on Context and Ontologies: Theory, Practice and Applications (C&O 2006) at the 17th European Conference on Artificial Intelligence (ECAI 2006). Riva del Garda, Italy, August 2006.

(BibTeX | Tags: personalization, context, information retrieval, semantics)

I. Cantador, M. Fernández, P. Castells. A Collaborative Recommendation Framework for Ontology Evaluation and Reuse. International Workshop on Recommender Systems at the 17th European Conference on Artificial Intelligence (ECAI 2006). Riva del Garda, Italy, August 2006.

(BibTeX | Tags: recommender systems, collaborative filtering, semantics, collaborative systems)

D. Vallet, M. Fernández, P. Castells, P. Mylonas, Y. Avrithis. Personalized Information Retrieval in Context. 3rd International Workshop on Modeling and Retrieval of Context (MRC 2006) at the 21st National Conference on Artificial Intelligence (AAAI 2006). Boston, MA, USA, July 2006.

(BibTeX | Tags: personalization, context, information retrieval, semantics)

M. Ruiz-Casado, E. Alfonseca, P. Castells. From Wikipedia to Semantic Relationships: a Semi-automated Annotation Approach. 1st Workshop on Semantic Wikis: From Wiki to Semantics, at the 3rd European Semantic Web Conference (ESWC 2006). Budva, Montenegro, June 2006.

(BibTeX | Tags: nlp, semantic annotation)

I. Cantador, P. Castells, D. Vallet. Enriching Group Profiles with Ontologies for Knowledge-Driven Collaborative Content Retrieval. 1st Int. Workshop on Semantic Technologies in Collaborative Applications (STICA 2006), at the 15th IEEE Workshops on Enabling Technologies: Infrastructures for Collaborative Enterprises (WETICE 2006). Manchester, UK, June 2006.

(BibTeX | Tags: recommender systems, collaborative filtering, information retrieval, semantics, group recommendation)

I. Cantador, P. Castells. Multilayered Ontology-Based User Profiles and Semantic Social Networks for Recommender Systems. 2nd Int. Workshop on Web Personalisation, Recommender Systems and Intelligent User Interfaces (WPRSIUI 2006) at the 4th Int. Conf. on Adaptive Hypermedia and Adaptive Web-Based Systems (AH 2006). Dublin, Ireland, June 2006.

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

I. Cantador, P. Castells. Building Emergent Social Networks and Group Profiles by Semantic User Preference Clustering. International Workshop on Semantic Network Analysis (SNA 2006) at the 3rd European Semantic Web Conference (ESWC 2006). Budva, Montenegro, June 2006.

(BibTeX | Tags: social networks, semantics, group recommendation)

M. Fernández I. Cantador, P. Castells. CORE: A Tool for Collaborative Ontology Reuse and Evaluation. 4th International Workshop on Evaluation of Ontologies for the Web (EON 2006) at the 15th International World Wide Web Conference (WWW 2006). Edinburgh, UK, May 2006.

(BibTeX | Tags: collaborative filtering, semantics, collaborative systems)

A. Evans, M. Fernández, D. Vallet, P. Castells. Adaptive Multimedia Access: From User Needs to Semantic Personalisation. IEEE International Symposium on Circuits and Systems (ISCAS 2006). Kos, Greece, May 2006.

(BibTeX | Tags: personalization, information retrieval, multimedia retrieval)

M. Fernández, D. Vallet, P. Castells. Probabilistic Score Normalization for Rank Aggregation. 28th European Conference on Information Retrieval (ECIR 2006), Springer Verlag Lecture Notes in Computer Science, Vol. 3936, ISBN 3-540-33347-9. London, UK, April 2006, pp. 553-556.
Poster

(BibTeX | Tags: rank fusion, information retrieval, rank aggregation, metasearch)

E. Alfonseca, M. Ruiz-Casado, M. Okumura, P. Castells. Towards Large-scale Non-taxonomic Relation Extraction: Estimating the Precision of Rote Extractors. 2nd Workshop on Ontology Learning and Population (OLP2) at the joint conf. of the Int. Committee on Computational Linguistics and the Association for Computational Linguistics (COLING / ACL 2006). Sydney, Australia, 2006.

(BibTeX | Tags: nlp, relation extraction, information extraction)

P. Castells, F. Perdrix, E. Pulido, M. Rico, J. M. Fuentes, V. R. Benjamins, J. Contreras, E. Piqué, J. Cal, J. Lorés, T. Granollers. Newspaper Archives on the Semantic Web. In R. Navarro-Prieto, J. Lorés-Vidal (Eds.): HCI related papers of Interacción 2004. Springer Verlag, 2006, ISSN: 1-4020-4204-3, pp. 267-276.

(BibTeX | Tags: semantics, news retrieval)

2005

D. Vallet, M. Fernández, P. Castells. The Quest for Information Retrieval on The Semantic Web. Upgrade 6 (6), Monograph: The Semantic Web, December 2005, pp. 19-23.

(BibTeX | Tags: semantic search, information retrieval)

P. Castells, M. Fernández, D. Vallet, P. Mylonas, Y. Avrithis. Self-Tuning Personalized Information Retrieval in an Ontology-Based Framework. 1st IFIP WG 2.12 & WG 12.4 International Workshop on Web Semantics (SWWS 2005). Springer Verlag Lecture Notes in Computer Science, Vol. 3762. Agia Napa, Cyprus, November 2005, ISSN: 3-540-29739-1, pp. 977-986.

(BibTeX | Tags: personalization, rank fusion, information retrieval, semantics, rank aggregation)

J. M. Fuentes, M. A. Corella, P. Castells, M. Rico. Semi-automatic Web Service Generation. IADIS WWW/Internet Conference (ICWI 2005). Lisbon, Portugal, October 2005, pp. 3-10.

(BibTeX | Tags: semantics, web services)

D. Vallet, P. Mylonas, M. A. Corella, J. M. Fuentes, P. Castells, Y. Avrithis. A Semantically-Enhanced Personalization Framework for Knowledge-Driven Media Services. IADIS WWW/Internet 2005 Conference (ICWI 2005). Lisbon, Portugal, October 2005, pp. 11-18.

(BibTeX | Tags: personalization, information retrieval)

M. Ruiz-Casado, E. Alfonseca, P. Castells. Using Context-window Overlapping in Synonym Discovery and Ontology Extension. International Conference on Recent Advances in Natural Language Processing (RANLP 2005). Borovets, Bulgaria, September 2005.

(BibTeX | Tags: nlp, information extraction)

M. A. Corella, J. M. Fuentes, P. Castells. Semi-automatic Web Service Generation and Classification. 2nd International Workshop on Semantic and Dynamic Web Processes (SDWP 2005). Orlando, Florida, July 2005, ISSN: 3-540-27996-2.

(BibTeX | Tags: web services)

M. Ruiz-Casado, E. Alfonseca, P. Castells. Automatic Assignment of Wikipedia Encyclopedic Entries to WordNet Synsets. 3rd Atlantic Web Intelligence Conference (AWIC 2005). Springer Verlag Lecture Notes in Computer Science, Vol. 3528. Lodz, Poland, June 2005, pp. 380-386.

(BibTeX | Tags: automatic disambiguation, nlp)

M. Ruiz-Casado, E. Alfonseca, P. Castells. Automatic Extraction of Semantic Relationships for WordNet by means of Pattern Learning from Wikipedia. 10th International Conference on Application of Natural Language to Information Systems (NLDB 2005). Springer Verlag Lecture Notes in Computer Science, Vol 3513. Alicante, Spain, June 2005, ISSN: 3-540-26031-5, pp. 67-79.

(BibTeX | Tags: nlp, relation extraction)

D. Vallet, M. Fernández, P. Castells. An Ontology-Based Information Retrieval Model. 2nd European Semantic Web Conference (ESWC 2005). Springer Verlag Lecture Notes in Computer Science, Vol. 3532. Heraklion, Greece, May 2005, ISSN: 3-540-26124-9, pp. 455-470.

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

2004

P. Castells, F. Perdrix, E. Pulido, M. Rico, R. Benjamins, J. Contreras, J. Lorés. Neptuno: Semantic Web Technologies for a Digital Newspaper Archive. 1st European Semantic Web Symposium (ESWS 2004). Springer Verlag Lecture Notes in Computer Science, Vol. 3053. Heraklion, Greece, May 2004, ISSN: 3-540-21999-4, pp. 445-458.

(BibTeX | Tags: semantics, news retrieval)

P. Castells, B. Foncillas, R. Lara, M. Rico, J. L. Alonso. Semantic Web Technologies for Economic and Financial Information Management. 1st European Semantic Web Symposium (ESWS 2004). Springer Verlag Lecture Notes in Computer Science, Vol. 3053. Heraklion, Greece, May 2004, ISSN: 3-540-21999-4, pp. 473-487.

(BibTeX | Tags: semantics, finance)