Background and activities

I'm working as a professor in the Department of Computer and Information Science here at NTNU. I'm affiliated with the Data and Information Management Group, where my main research interests include distributed and parallel database systems, query processing, information retrieval,  and Big Data in general.

Teaching

I'm currently involved in the following courses:

  • Big Data architcture
  • Data warehousing and data mining
  • Advanced database systems

In addition, I also give PhD courses (run as seminars) on the following topics:

  • Temporal infomation retrieval
  • Advanced topics in database systems
  • Web mining

Previous teching has been on a wide range of topics, including Information retrieval, Distributed systems, Data modelling and database systems, Operating Systems, Algorithms and data structures, Computer architecture, and Computer systems.

Research Projects

I have been involved in a number of projects during recent years, including:

As a Principal Investigator:

As a project member:

As participant:

Publications

Below are some selected publications from recent years. For a complete list, including links to preprints of the papers, please check out my CV.

 

Scientific, academic and artistic work

Displaying a selection of activities. See all publications in the database

Journal publications

Part of book/report

  • Gkorgkas, Orestis; Vlachou, Akrivi; Doulkeridis, Christos; Nørvåg, Kjetil. (2015) Finding the Most Diverse Products using Preference Queries. Advances in Database Technology - EDBT 2015, 18th International Conference on Extending Database Technology, Brussels, Belgium, March 23-27, Proceedings.
  • Gkorgkas, Orestis; Vlachou, Akrivi; Doulkeridis, Christos; Nørvåg, Kjetil. (2014) Efficient processing of exploratory top-k joins. Conference on Scientific and Statistical Database Management, SSDBM '14, Aalborg, Denmark, June 30 - July 02, 2014.
  • Kotsakos, Dimitrios; Lappas, Theodoros; Kotzias, Dimitrios; Gunopulos, Dimitrios; Kanhabua, Nattiya; Nørvåg, Kjetil. (2014) A burstiness-aware approach for document dating. The 37th International ACM SIGIR Conference on Research and Development in Information Retrieval, SIGIR '14, Gold Coast , QLD, Australia - July 06 - 11, 2014.
  • Ciglan, Marek; Laclavik, Michal; Nørvåg, Kjetil. (2013) On community detection in real-world networks and the importance of degree assortativity. The 19th ACM SIGKDD International Conference on Knowledge Discovery and Data Mining, KDD 2013, Chicago, IL, USA, August 11-14, 2013.
  • Vlachou, Akrivi; Doulkeridis, Christos; Nørvåg, Kjetil; Kotidis, Yannis. (2013) Branch-and-bound algorithm for reverse top-k queries. Proceedings of the ACM SIGMOD International Conference on Management of Data, SIGMOD 2013, New York, NY, USA, June 22-27, 2013.
  • Ciglan, Marek; Nørvåg, Kjetil; Hluchy, Ladislav. (2012) The SemSets model for ad-hoc semantic list search. Proceedings of the 21st World Wide Web Conference 2012, WWW 2012, Lyon, France, April 16-20, 2012.
  • Kanhabua, Nattiya; Berberich, Klaus; Nørvåg, Kjetil. (2012) Learning to select a time-aware retrieval model. The 35th International ACM SIGIR conference on research and development in Information Retrieval, SIGIR '12, Portland, OR, USA, August 12-16, 2012.
  • Kanhabua, Nattiya; Nørvåg, Kjetil. (2012) Estimating query difficulty for news prediction retrieval. 21st ACM International Conference on Information and Knowledge Management, CIKM'12, Maui, HI, USA, October 29 - November 02, 2012.
  • Kanhabua, Nattiya; Nørvåg, Kjetil. (2012) Learning to rank search results for time-sensitive queries. 21st ACM International Conference on Information and Knowledge Management, CIKM'12, Maui, HI, USA, October 29 - November 02, 2012.
  • Rocha-Junior, Joao B.; Nørvåg, Kjetil. (2012) Top-k spatial keyword queries on road networks. 15th International Conference on Extending Database Technology, EDBT '12, Berlin, Germany, March 27-30, 2012, Proceedings.
  • Tsatsaronis, George; Varlamis, Iraklis; Nørvåg, Kjetil. (2012) SemaFor: semantic document indexing using semantic forests. 21st ACM International Conference on Information and Knowledge Management, CIKM'12, Maui, HI, USA, October 29 - November 02, 2012.
  • Kanhabua, Nattiya; Nørvåg, Kjetil. (2011) A comparison of time-aware ranking methods. Proceeding of the 34th International ACM SIGIR Conference on Research and Development in Information Retrieval, SIGIR 2011.
  • Kanhabua, Nattiya; Nørvåg, Kjetil. (2011) Time-based query performance predictors. Proceeding of the 34th International ACM SIGIR Conference on Research and Development in Information Retrieval, SIGIR 2011.
  • Rocha-Junior, Joao B.; Vlachou, Akrivi; Doulkeridis, Christos; Nørvåg, Kjetil. (2011) Efficient Execution Plans for Distributed Skyline Query Processing. EDBT/ICDT 2011 Joint Conference.
  • Ciglan, Marek; Nørvåg, Kjetil. (2010) WikiPop: personalized event detection system based on Wikipedia page view statistics. Proceedings of the 19th ACM international conference on Information and knowledge management.
  • Vlachou, Akrivi; Doulkeridis, Christos; Kotidis, Yannis; Nørvåg, Kjetil. (2010) Reverse Top-k Queries. 26th International Conference on Data Engineering. Conference Proceedings.
  • Zhang, Xiangliang; Wang, Wei; Nørvåg, Kjetil; Sebag, Michele. (2010) K-AP: Generating Specified K Clusters by Efficient Affinity Propagation. 10th IEEE International Conference on Data Mining, Proceedings.
  • Doulkeridis, Christos; Vlachou, Akrivi; Nørvåg, Kjetil; Kotidis, Yannis; Vazirgiannis, Michalis. (2009) Multidimensional Routing Indices for Efficient Distributed Query Processing. Proceedings of 18th ACM Conference on Information and Knowledge Management (CIKM'09).
  • Vlachou, Akrivi; Doulkeridis, Christos; Nørvåg, Kjetil; Vazirgiannis, Michalis. (2008) Skyline-based Peer-to-Peer Top-k Query Processing. Proceedings of the 2008 IEEE 24th International Conference on Data Engineering.
  • Hauglid, Jon Olav; Nørvåg, Kjetil. (2008) PROQID: Partial Restarts of Queries in Distributed Databases. Proceedings of ACM 17th Conference on Information and Knowledge Management (CIKM 08).
  • Vlachou, Akrivi; Doulkeiridis, Christos; Nørvåg, Kjetil; Vazirgiannis, Michalis. (2008) On efficient top-k query processing in highly distributed environments. Proceedings of the ACM SIGMOD International Conference on Management of Data, SIGMOD 2008, Vancouver, BC, Canada.