Ludo Waltman, PhD

Ludo Waltman is a researcher at the Centre for Science and Technology Studies (CWTS) of Leiden University. At CWTS, Ludo coordinates the advanced bibliometric methods (ABM) working group. Ludo's research interests focus on methodological topics in the fields of bibliometrics and scientometrics, in particular the analysis and visualization of bibliometric networks and the development of bibliometric indicators. Together with his colleague Nees Jan van Eck, Ludo has developed two software tools for the analysis and visualization of bibliometric networks: VOSviewer and CitNetExplorer. Ludo also serves as Editor-in-Chief of Journal of Informetrics. In addition to his research activities, Ludo is involved in numerous contract research projects. Ludo also performs various ICT tasks at CWTS.

See also Ludo's personal website.

 

Publications

Journal publications (52)

Conference publications (18)

  • Waltman, L., & Van Eck, N.J. (2015). Field-normalized citation impact indicators and the choice of an appropriate counting method. In Proceedings of the 15th International Conference of the International Society for Scientometrics and Informetrics (pp. 328-339).
  • Van Eck, N.J., & Waltman, L. (2014). CitNetExplorer: A new software tool for analyzing and visualizing citation networks. In Proceedings of the 19th International Conference on Science and Technology Indicators (pp. 181-192).
  • Costas, R., Calero-Medina, C.M., Waltman, L., & Wouters, P. (2013). The relationship between the performance of editorial board members and the impact of scientific journals: an exploratory analysis. In Proceedings of 18th International Conference on Science and Technology Indicators (pp. 87-95).
  • Waltman, L., & Van Eck, N.J. (2013). A systematic empirical comparison of different approaches for normalizing citation impact indicators. In Proceedings of the 14th International Conference of the International Society for Scientometrics and Informetrics (pp. 1649-1664).
  • Waltman, L., Wouters, P., & Van Eck, N.J. (2013). Counting publications and citations: Is more always better? 14th International Conference of the International Society for Scientometrics and Informetrics, Vienna. In Proceedings of the 14th International Conference of the International Society for Scientometrics and Informetrics (pp. 455-467).
  • Tijssen, R.J.W., Waltman, L., & Van Eck, N.J. (2012). Research collaboration and the expanding science grid: Measuring globalization processes worldwide. In Proceedings of the 17th International Conference on Science and Technology Indicators (pp. 779-790).
  • Waltman, L., & Van Eck, N.J. (2012). Constructing a publication-level classification system of science. In Proceedings of the 17th International Conference on Science and Technology Indicators (pp. 803-814).
  • Waltman, L., Calero-Medina, C.M., Kosten, M.J.F., Noyons, E.C.M., Tijssen, R.J.W., Van Eck, N.J., Van Leeuwen, T.N., Van Raan, A.F.J., Visser, M.S., & Wouters, P. (2012). The Leiden Ranking 2011/2012: Data collection, indicators, and interpretation. In Proceedings of the 17th International Conference on Science and Technology Indicators (pp. 791-802).
  • Van Eck, N.J., Tijssen, R.J.W., & Waltman, L. (2011). Globalization of public-private research in worldwide science: co-publication trends and geographical distances between research partners . In Proceedings of the 2011 Atlanta Conference on Science and Innovation Policy.
  • Van Eck, N.J., Waltman, L., & Tijssen, R.J.W. (2011). Globalization of science: Geographical distance measurements of research collaboration. In Proceedings of the 13th International Conference of the International Society for Scientometrics and Informetrics (pp. 181-186).
  • Waltman, L., & Bornmann, L. (2011). The detection of "hot regions" in the geography of science - A visualization approach by using density maps. The13th Conference of the International Society for Scientometrics and Informetrics. In Proceedings of the 13th International Conference of the International Society for Scientometrics and Informetrics (pp. 1076-1078).
  • Van Eck, N.J., & Waltman, L. (2009). VOSviewer: A computer program for bibliometric mapping. In Proceedings of the 12th International Conference on Scientometrics and Informetrics (pp. 886-897).
  • Waltman, L., & Van Eck, N.J. (2009). A Taxonomy of Bibliometric Performance Indicators Based on the Property of Consistency. In Proceedings of the 12th International Conference of the International Society for Scientometrics and Informetrics (pp. 1002-1003).
  • Waltman, L., & Kaymak, U. (2007). A theoretical analysis of cooperative behaviorin multi-agent Q-learning. In Proceedings of the 2007 IEEE International Symposium on Approximate Dynamic Programming and Reinforcement Learning (pp. 84-91). doi:10.1109/ADPRL.2007.368173.
  • Van Eck, N.J., Waltman, L., Van den Berg, J., & Kaymak, U. (2006). Visualizing the WCCI 2006 knowledge domain. In Proceedings of the 2006 IEEE International Conference on Fuzzy Systems (pp. 1671-1678). doi:10.1109/FUZZY.2006.1681931.
  • Van Eck, N.J., Waltman, L., & Van den Berg, J. (2005). A novel algorithm for visualizing concept associations. In Proceedings of the 16th International Workshop on Database and Expert Systems Applications (pp. 405-409). doi:10.1109/DEXA.2005.23.
  • Waltman, L., Kaymak, U., & Van den Berg, J. (2005). Maximum likelihood parameter estimation in probabilistic fuzzy classifiers. In Proceedings of the 2005 IEEE International Conference on Fuzzy Systems (pp. 1098-1103). doi:10.1109/FUZZY.2005.1452548.
  • Van den Berg, J., Van Eck, N.J., Waltman, L., & Kaymak, U. (2004). A VICORE architecture for intelligent knowledge management. In Proceedings of the KDNet Symposium on Knowledge-Based Services for the Public Sector (pp. 63-74).

Book chapters (2)

Researcher and Deputy Director of CWTS

T: +31 71 527 5806

E: waltmanlr@cwts.leidenuniv.nl

W: www.ludowaltman.nl


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