April 27, 2023. The paper Academic information retrieval using citation clusters: In-depth evaluation based on systematic reviews by Juan Pablo Bascur, Suzan Verberne, Nees Jan van Eck, and Ludo Waltman has been published in volume 128 of Scientometrics.
February 21, 2023. The blog post The preprint revolution - Implications for bibliographic databases by Ludo Waltman and Nees Jan van Eck has been published on Upstream.
January 23, 2023. VOSviewer version 1.6.19 has been released and is available for download. This new version offers a number of improvements in VOSviewer's support for creating maps based on OpenAlex data. It also fixes some problems in creating maps based on Web of Science data.
January 2, 2023. The paper Capillary electrophoresis - A bibliometric analysis by Magnus Palmblad, Nees Jan van Eck, and Jonas Bergquist has been published in volume 159 of TrAC Trends in Analytical Chemistry.
December 7, 2022. The blog post Take responsibility for social media by Vincent Traag, Jonathan Dudek, Eleonora Dagiene, Nees Jan van Eck, and Rodrigo Costas has been published on Leiden Madtrics.
November 1, 2022. The paper Funding COVID-19 research: Insights from an exploratory analysis using open data infrastructures by Alexis-Michel Mugabushaka, Nees Jan van Eck, and Ludo Waltman has been published in volume 3, issue 3 of Quantitative Science Studies.
October 25, 2022. VOSviewer Online version 1.2.0 has been released. This new version exposes VOSviewer Online as a React component. The VOSviewer Online React component package is available on npm and offers an easy way to integrate VOSviewer Online into web sites and applications.
August 29, 2022. networkanalysis-ts version 1.0.0 has been released. The networkanalysis-ts package is a TypeScript port of the Java networkanalysis package. The package provides algorithms and data structures for network analysis. It contains an implementation of the Leiden algorithm and the Louvain algorithm for network clustering and the VOS technique for network layout.
July 12, 2022. The slides of the online presentation The evolving landscape of scholarly metadata: Preprints and open peer reviews that Ludo Waltman and I gave today at the CWTS Research Seminar are available here.
July 7, 2022. The paper Crossref as a source of open bibliographic metadata by Nees Jan van Eck and Ludo Waltman has been published on MetaArXiv.
July 7, 2022. The paper Academic information retrieval using citation clusters: In-depth evaluation based on systematic reviews by Juan Pablo Bascur, Suzan Verberne, Nees Jan van Eck, and Ludo Waltman has been published on arXiv.
July 6, 2022. The blog post The growth of open peer review by Ludo Waltman and Nees Jan van Eck has been published on Leiden Madtrics.
June 22, 2022. The CWTS Leiden Ranking 2022 has been published. The number of universities included in the ranking has increased from 1225 to 1318.
February 25, 2022. The blog post Funding Covid-19 research: Insights from an open data infrastructure by Alexis-Michel Mugabushaka, Nees Jan van Eck, and Ludo Waltman has been published on Upstream.
January 24, 2022. VOSviewer version 1.6.18 has been released and is available for download. This new version of VOSviewer offers improved support for creating maps based on OpenAlex, Europe PMC, Semantic Scholar, and Crossref data.
January 19, 2022. The blog post A first step in quantifying disagreement across science by Wout Lamers, Kevin Boyack, Vincent Larivière, Cassidy Sugimoto, Nees Jan van Eck, Ludo Waltman, and Dakota Murray has been published on Leiden Madtrics.
January 4, 2022. VOSviewer Online version 1.1.0 has been released. This new version of VOSviewer Online offers improved support for sharing a visualization.
December 24, 2021. The paper Meta-Research: Investigating disagreement in the scientific literature by Wout Lamers, Kevin Boyack, Vincent Larivière, Cassidy Sugimoto, Nees Jan van Eck, Ludo Waltman, and Dakota Murray has been published in volume 10 of eLife.
October 21, 2021. The slides of the workshop that I gave today at the VOGIN-IP-lezing in Amsterdam are available here.
August 4, 2021. VOSviewer Online has been integrated in Digital Science's Dimensions platform, making it very easy for Dimensions users to create VOSviewer visualizations of co-authorship networks and citation networks. More information is available in this blog post.
July 30, 2021. The paper Measuring Disagreement in Science by Wout Lamers, Kevin Boyack, Vincent Larivière, Cassidy Sugimoto, Nees Jan van Eck, Ludo Waltman, and Dakota Murray has been published in arXiv.
July 22, 2021. VOSviewer version 1.6.17 has been released and is available for download. This new version of VOSviewer offers support for sharing maps online and for creating maps based on files exported from the Lens. More information can be found in this blog post.
July 16, 2021. VOSviewer Online has been released! VOSviewer Online is a web-based version of VOSviewer. It runs in a web browser and can be used to share interactive visualizations and to embed these visualizations in online platforms. More information can be found in this blog post.
July 12, 2021. The slides of my presentations at the 18th International Conference on Scientometrics & Informetrics are available here.
July 8, 2021. The CWTS Leiden Ranking 2021 has been published. The number of universities included in the ranking has increased from 1176 to 1225, and the number of countries with at least one university in the ranking has increased from 65 to 69. More information is available here.
April 8, 2021. The paper Large-scale comparison of bibliographic data sources: Scopus, Web of Science, Dimensions, Crossref, and Microsoft Academic by Martijn Visser, Nees Jan van Eck, and Ludo Waltman has been published in volume 2, issue 1 of Quantitative Science Studies.
February 8, 2021. I am very honored that I received the award for Best EGSH Teacher 2020. More information about the EGSH PhD Excellence Awards can be found here.
January 7, 2021. The paper A scientometric overview of CORD-19 by Giovanni Colavizza, Rodrigo Costas, Vincent Traag, Nees Jan van Eck, Thed van Leeuwen, and Ludo Waltman has been published in volume 16, issue 1 of PLOS ONE.
November 25, 2020. VOSviewer version 1.6.16 has been released and is available for download. It also offers new functionality for querying the Microsoft Academic API using author, affiliation, and journal IDs and for creating term co-occurrence maps based on Semantic Scholar data.
July 1, 2020. The slides of the keynote presentation that I gave today at the International Conference on ICT enhanced Social Sciences and Humanities 2020 are available here.
June 25, 2020. The paper Enhancing direct citations: A comparison of relatedness measures for community detection in a large set of PubMed publications by Per Ahlgren, Yunwei Chen, Cristian Colliander, and Nees Jan van Eck has been published in volume 1, issue 2 of Quantitative Science Studies.
June 25, 2020. The paper A principled methodology for comparing relatedness measures for clustering publications by Ludo Waltman, Kevin Boyack, Giovanni Colavizza, and Nees Jan van Eck has been published in volume 1, issue 2 of Quantitative Science Studies.
May 22, 2020. The paper Large-scale comparison of bibliographic data sources: Scopus, Web of Science, Dimensions, Crossref, and Microsoft Academic by Martijn Visser, Nees Jan van Eck, and Ludo Waltman has been published in arXiv.
May 19, 2020. The paper Collecting large-scale publication data at the level of individual researchers: A practical proposal for author name disambiguation by Ciriaco Andrea D'Angelo and Nees Jan van Eck has been published in volume 123, issue 2 of Scientometrics.
April 20, 2020. The paper A scientometric overview of CORD-19 by Giovanni Colavizza, Rodrigo Costas, Vincent A. Traag, Nees Jan van Eck, Thed van Leeuwen, and Ludo Waltman has been published in bioRxiv.
April 1, 2020. VOSviewer version 1.6.15 has been released and is available for download. This new version of VOSviewer offers improved support for querying the Microsoft Academic API.
February 20, 2020. The paper Comparing institutional-level bibliometric research performance indicator values based on different affiliation disambiguation systems by Paul Donner, Christine Rimmert, and Nees Jan van Eck has been published in the first issue of Quantitative Science Studies.
January 27, 2020. VOSviewer version 1.6.14 has been released and is available for download.
January 15, 2020. The paper Intermediacy of publications by Lovro Subelj, Ludo Waltman, Vincent Traag, and Nees Jan van Eck has been published in Royal Society Open Science.
September 30, 2019. The Research on Research Institute (RoRI), a collaboration of Wellcome Trust, Digital Science, University of Sheffield, and Leiden University, has been launched. The institute has made available an online tool for exploring research funding landscapes.
September 16, 2019. VOSviewer version 1.6.13 has been released and is available for download.
September 4, 2019. The slides of the presentations that I gave today at the 17th International Conference on Scientometrics & Informetrics in Rome are available here and here.
September 4, 2019. The slides of the presentation that I gave today at the Workshop on Open Citations: Opportunities and Ongoing Developments in Rome are available here.
August 31, 2019. VOSviewer version 1.6.12 has been released and is available for download. This new version of VOSviewer offers support for working with Microsoft Academic data.
May 15, 2019. The 2019 edition of the CWTS Leiden Ranking has been released. This edition includes new indicators of open access publishing and gender balance. Read more in this blog post.
April 15, 2019. The slides of the presentations that I gave today at Wuhan University in Beijing are available here and here.
April 12, 2019. The slides of the presentations that I gave today at Chinese Academy of Sciences in Beijing are available here and here.
April 3, 2019. VOSviewer version 1.6.11 has been released and is available for download.
March 26, 2019. The paper From Louvain to Leiden: Guaranteeing well-connected communities by Vincent Traag, Ludo Waltman, and Nees Jan van Eck has been published in Scientific Reports.
March 12, 2019. The slides of the presentation that I gave today at Uppsala University in Uppsala are available here.
March 1, 2019. The slides of the presentation that I gave today at the Workshop on Open Scientometric Data Infrastructures in Leiden are available here.
January 23, 2019. The paper A principled methodology for comparing relatedness measures for clustering publications by Ludo Waltman, Kevin Boyack, Giovanni Colavizza, and Nees Jan van Eck has been published in the arXiv.
January 10, 2019. VOSviewer version 1.6.10 has been released and is available at www.vosviewer.com. More information is available in a blog post.
December 21, 2018. The paper Intermediacy of publications by Lovro Subelj, Ludo Waltman, Vincent Traag, and Nees Jan van Eck has been published in the arXiv.
December 7, 2018. The slides of the presentation that I gave today at the Data Science seminar at the Faculty of Social and Behavioural Sciences of Leiden University in Leiden are available here.
December 5, 2018. The paper Analyzing the activities of visitors of the Leiden Ranking website by Nees Jan van Eck and Ludo Waltman has been published in volume 3, issue 3 of Journal of Data and Information Science.
November 28, 2018. The paper Exploring topics of interest of Mendeley users by Zohreh Zahedi and Nees Jan van Eck has been published in volume 1, issue 1 of Journal of Altmetrics.
November 14, 2018. The paper Framing psychology as a discipline (1950-1999): A large-scale term co-occurrence analysis of scientific literature in psychology by Ivan Flis and Nees Jan van Eck has been published in volume 21, issue 4 of History of Psychology.
November 5, 2018. The paper Analyzing the activities of visitors of the Leiden Ranking website by Nees Jan van Eck and Ludo Waltman has been accepted for publication in Journal of Data and Information Science.
November 7, 2018. The paper Where are the breaks in translation from theory to clinical practice (and back) in addressing depression? An empirical graph-theoretic approach by Greg Siegle1, Angélique Cramer, Nees Jan van Eck, Philip Spinhoven, Steven Hollon, Johan Ormel, Marlene Strege, and Claudi Bockting has been accepted for publication in Psychological Medicine.
October 22, 2018. The paper From Louvain to Leiden: Guaranteeing well-connected communities by Vincent Traag, Ludo Waltman, and Nees Jan van Eck has been published in the arXiv. The paper is also discussed in a blog post. The source code of the Leiden algorithm is available on GitHub.
October 20, 2018. The paper Exploring topics of interest of Mendeley users by Zohreh Zahedi and Nees Jan van Eck has been accepted for publication in Journal of Altmetrics.
September 28, 2018. The slides of the presentation that I gave today at the Colloquium Research Information Systems and Science Classifications: Revisiting the NARCIS Classification in The Hague are available here.
September 4, 2018. The slides of the presentation that I gave today at the Workshop on Open Citations in Bologna are available here.
September 1, 2018. The paper From dignity to security protocols: A scientometric analysis of digital ethics by René Mahieu, Nees Jan van Eck, David van Putten, and Jeroen van den Hoven has been published in volume 20, issue 3 of Ethics and Information Technology.
August 29, 2018. VOSviewer version 1.6.9 has been released and is available at www.vosviewer.com. More information is available in a blog post.
May 7, 2018. The paper From dignity to security protocols: A scientometric analysis of digital ethics by René Mahieu, Nees Jan van Eck, David van Putten, and Jeroen van den Hoven has been accepted for publication in Ethics and Information Technology.
May 16, 2018. The CWTS Leiden Ranking 2018 has been released and is available at www.leidenranking.com.
April 27, 2018. VOSviewer version 1.6.8 has been released and is available at www.vosviewer.com.
March 6, 2018. The paper The closer the better: Similarity of publication pairs at different co-citation levels by Giovanni Colavizza, Kevin Boyack, Nees Jan van Eck, and Ludo Waltman has been published in volume 69, issue 4 of the Journal of the Association for Information Science and Technology.
March 1, 2018. The paper Bibliometric analyses reveal patterns of collaboration between ASMS members by Magnus Palmblad and Nees Jan van Eck has been published in volume 29, issue 3 of the Journal of The American Society for Mass Spectrometry.
February 16, 2018. VOSviewer version 1.6.7 has been released and is available at www.vosviewer.com. More information is available here.
December 5, 2017. If you want to support open citations, then please consider signing this letter.
December 1, 2017. The paper Characterizing in-text citations in scientific articles: A large-scale analysis by Kevin Boyack, Nees Jan van Eck, Giovanni Colavizza, and Ludo Waltman has been published in volume 12, issue 1 of the Journal of Informetrics.
November 15, 2018. The paper Bibliometric analyses reveal patterns of collaboration between ASMS members by Magnus Palmblad and Nees Jan van Eck has been accepted for publication the Journal of The American Society for Mass Spectrometry.
October 23, 2017. VOSviewer version 1.6.6 has been released and is available at www.vosviewer.com. More information is available here.
October 19, 2017. The slides of the presentations that I gave today at the 16th International Conference on Scientometrics & Informetrics in Wuhan are available here and here.
October 8, 2017. The paper The closer the better: Similarity of publication pairs at different co-citation levels by Giovanni Colavizza, Kevin Boyack, Nees Jan van Eck, and Ludo Waltman has been accepted for publication in the Journal of the Association for Information Science and Technology.
September 14, 2017. The slides of the presentation that I gave today at the ALPSP 10th Annual Conference and Awards in Noordwijk are available here.
June 28, 2017. The slides of the presentation that I gave today at the 2017 BenchTech Seminar at the Technical University Munich in Munich are available here.
May 29, 2017. The slides of the presentation that I gave today at the Workshop: "University rankings: A challenge of a foe?" at the University of Milan in Milan are available here.
May 20, 2017. The paper Framing psychology as a discipline (1950-1999): A large-scale term co-occurrence analysis of scientific literature in psychology by Ivan Flis and Nees Jan van Eck has been accepted for publication in History of Psychology.
May 17, 2017. The CWTS Leiden Ranking 2017 has been released and is available at www.leidenranking.com. Ten principles for the responsible use of university rankings are presented in this blog post.
March 30, 2017. The slides of the presentation that I gave today at the EXCITE Workshop 2017: "Challenges in Extracting and Managing References" at GESIS - Leibniz Institute for the Social Sciences in Cologne are available here.
April 24, 2017. The paper Citation-based clustering of publications using CitNetExplorer and VOSviewer by Nees Jan van Eck and Ludo Waltman has been published in volume 111, issue 2 of Scientometrics.
October 28, 2016. The paper Constructing bibliometric networks: A comparison between full and fractional counting by Antonio Perianes-Rodriguez, Ludo Waltman, and Nees Jan van Eck has been published in volume 10, issue 4 of the Journal of Informetrics.
October 24, 2016. The paper Constructing bibliometric networks: A comparison between full and fractional counting by Antonio Perianes-Rodriguez, Ludo Waltman, and Nees Jan van Eck has been accepted for publication in the Journal of Informetrics.
September 28, 2016. VOSviewer version 1.6.5 has been released and is available at www.vosviewer.com. More information is available here.
September 16, 2016. The paper Evaluation of the citation matching algorithms of CWTS and iFQ in comparison to Web of Science by Marlies Olensky, Marion Schmidt, and Nees Jan van Eck has been published in volume 67, issue 10 of Journal of the Association for Information Science and Technology (JASIST).
August 29, 2016. The interactive version of the VOSviewer visualizations showing the focal areas in Chinese science published last Saturday in the Dutch newspaper Trouw is available here.
June 22, 2016. The slides of the presentation that I gave today at the Training Cource on "Big data and academic publication" at the National Library of the Chinese Academy of Sciences in Beijing are available here.
June 20, 2016. The slides of the presentation that I gave today at the International Conference on Data-driven Discovery: "When Data Science Meets Information Science" at the National Library of the Chinese Academy of Sciences in Beijing are available here.
May 18, 2016. The CWTS Leiden Ranking 2016 has been released and is available at www.leidenranking.com. More information on the improvements made in the 2016 edition of the CWTS Leiden Ranking is available in this blog post.
April 28, 2016. The paper Clustering scientific publications based on citation relations: A systematic comparison of different methods by Lovro Subelj, Nees Jan van Eck, and Ludo Waltman has been published in volume 10, issue 2 of PLOS ONE.
April 18, 2016. The paper Clustering scientific publications based on citation relations: A systematic comparison of different methods by Lovro Subelj, Nees Jan van Eck, and Ludo Waltman has been accepted for publication in PLOS ONE.
April 7, 2016. VOSviewer version 1.6.4 has been released and is available at www.vosviewer.com.
November 27, 2015. The slides of the presentation that I gave today at the LCN2 Seminar in Leiden are available here.
November 13, 2015. The slides of the presentation that I gave today at the 8th LCDS Meeting on Statistics & Data Science in Leiden are available here.
October 27, 2015. VOSviewer version 1.6.3 has been released and is available at www.vosviewer.com.
September 19, 2015. The paper Field-normalized citation impact indicators and the choice of an appropriate counting method by Ludo Waltman and Nees Jan van Eck has been published in volume 9, issue 4 of the Journal of Informetrics.
August 27, 2015. VOSviewer version 1.6.2 has been released and is available at www.vosviewer.com.
August 3, 2015. The paper Field-normalized citation impact indicators and the choice of an appropriate counting method by Ludo Waltman and Nees Jan van Eck has been accepted for publication in the Journal of Informetrics.
June 30, 2015. The slides of the presentation that I gave today at the 15th International Conference on Scientometrics & Informetrics in Istanbul are available here.
June 29, 2015. The slides of the VOSviewer and CitNetExplorer tutorial that I gave today at the 15th International Conference on Scientometrics & Informetrics in Istanbul are available here.
June 11, 2015. The paper Evaluation of the citation matching algorithms of CWTS and iFQ in comparison to Web of Science by Marlies Olensky, Marion Schmidt, and Nees Jan van Eck has been accepted for publication in the Journal of the Association for Information Science and Technology (JASIST).
May 20, 2015. The CWTS Leiden Ranking 2015 has been released and is available at www.leidenranking.com. This is a ranking of the 750 largest universities worldwide (in terms of publication output in the Web of Science database) based on bibliometric indicators.
May 7, 2015. The slides of the presentation that I gave today at the Translantis Digital Humanities Colloquium at Utrecht University are available here.
April 30, 2015. The slides of the presentation that I gave today at the Fifth International Workshop on Social Network Analysis in Capri are available here.
April 20, 2015. The slides of the presentation that I gave today at the workshop Comparison of Algorithms in Amsterdam are available here.
March 16, 2015. VOSviewer version 1.6.1 has been released and is available at www.vosviewer.com.
February 12, 2015. The slides of the presentation that I gave today at the International Workshop on Quantifying Scientific Impact: Networks, Measures, Insights? at ETH Zurich are available here.
January 12, 2015. VOSviewer version 1.6.0 has been released and is available at www.vosviewer.com.
November 5, 2014. The slides of the presentation that I gave today at the Annual Research Directors' Forum Meeting at Stellenbosch University are available here.
September 3, 2014. The slides of the presentation that I gave today at the Science and Technology Indicators Conference are available here.
September 2, 2014. The slides of the presentation that I gave today at the workshop Bibliometric Indicators at Leiden University are available here.
August 29, 2014. The slides of the presentation that I gave today at the workshop Topic Identification at Humboldt-Universität are available here.
August 28, 2014. The paper CitNetExplorer: A new software tool for analyzing and visualizing citation networks by Nees Jan van Eck and Ludo Waltman has been published in volume 8, issue 4 of the Journal of Informetrics.
July 22, 2014. The paper CitNetExplorer: A new software tool for analyzing and visualizing citation networks by Nees Jan van Eck and Ludo Waltman has been accepted for publication in the Journal of Informetrics.
June 2, 2014. VOSviewer version 1.5.7 has been released and is available at www.vosviewer.com.
May 15, 2014. VOSviewer version 1.5.6 has been released and is available at www.vosviewer.com.
May 7, 2014. The radio interview I did with the Dutch radio station SleutelStadFM about the CWTS Leiden Ranking 2014 is now available online.
April 30, 2014. The CWTS Leiden Ranking 2014 has been released and is available at www.leidenranking.com. This is a ranking of the 750 largest universities worldwide (in terms of publication output in the Web of Science database) based on bibliometric indicators.
March 13, 2014. The paper Mapping patient safety: A large-scale analysis of the literature using bibliometric visualization techniques by Sharon Rodrigues, Nees Jan van Eck, Ludo Waltman, and Frank Willem Jansen has been published in volume 4 of BMJ Open.
March 10, 2014. CitNetExplorer version 1.0.0 has been released and is available at www.citnetexplorer.nl. CitNetExplorer, developed together with Nees Jan van Eck, is a new software tool for visualizing and analyzing citation networks of scientific publications.
February 17, 2014. The paper Mapping patient safety: A large-scale analysis of the literature using bibliometric visualization techniques by Sharon Rodrigues, Nees Jan van Eck, Ludo Waltman, and Frank Willem Jansen has been accepted for publication in BMJ Open.
January 24, 2014. The slides of the presentation that I gave today at the Eurandom workshop Networks with community structure are available here.
December 9, 2013. The recently developed smart local moving algorithm for large-scale community detection has been included in version 1.1 of the Sci2 tool.
December 7, 2013. VOSviewer version 1.5.5 has been released and is available at www.vosviewer.com.
November 26, 2013. The science map Visualizing trends and dynamics: 30 years of scientific development by Nees Jan van Eck, Ludo Waltman, and Ferdy van Gool, which is included in the 9th iteration of the Places & Spaces: Mapping Science exhibit, has become available online.
November 13, 2013. The paper A smart local moving algorithm for large-scale modularity-based community detection by Ludo Waltman and Nees Jan van Eck has been published in volume 86 of the European Physical Journal B.
November 10, 2013. The paper An evolutionary model of price competition among spatially distributed firms by Ludo Waltman, Nees Jan van Eck, Rommert Dekker and Uzay Kaymak has been published in volume 42, issue 4 of Computational Economics.
October 23, 2013. The paper The production of scientific knowledge on renewable energies: Worldwide trends, dynamics and challenges and implications for management by Francesco Rizzi, Nees Jan van Eck, and Marco Frey has been published in volume 62 of Renewable Energy.
October 7, 2013. The paper A smart local moving algorithm for large-scale modularity-based community detection by Ludo Waltman and Nees Jan van Eck has been accepted for publication in the European Physical Journal B.
September 2, 2013. The slides of the presentation that I gave today at the workshop Measuring the diversity of research are available here.
August 31, 2013. The paper A systematic empirical comparison of different approaches for normalizing citation impact indicators by Ludo Waltman and Nees Jan van Eck has been published in volume 7, issue 4 of the Journal of Informetrics.
August 28, 2013. The paper The production of scientific knowledge on renewable energies: Worldwide trends, dynamics and challenges and implications for management by Francesco Rizzi and Nees Jan van Eck has been accepted for publication in Renewable Energy.
August 19, 2013. The paper Source normalized indicators of citation impact: An overview of different approaches and an empirical comparison by Ludo Waltman and Nees Jan van Eck has been published in volume 96, issue 3 of Scientometrics.
August 6, 2013. The paper A systematic empirical comparison of different approaches for normalizing citation impact indicators by Ludo Waltman and Nees Jan van Eck has been accepted for publication in the Journal of Informetrics.
April 30, 2013. The paper Counting publications and citations: Is more always better? by Ludo Waltman, Nees Jan van Eck, and Paul Wouters has been published in volume 7, issue 3 of the Journal of Informetrics.
April 25, 2013. The paper Citation analysis may severely underestimate the impact of clinical research as compared to basic research by Nees Jan van Eck, Ludo Waltman, Anthony van Raan, Robert Klautz, and Wilco Peul has been published in volume 8, issue 4 of PLoS ONE.
April 17, 2013. The CWTS Leiden Ranking 2013 has been released and is available at www.leidenranking.com. This is a ranking of the 500 largest universities worldwide (in terms of publication output in the Web of Science database) based on bibliometric indicators.
April 2, 2013. The paper Counting publications and citations: Is more always better? by Ludo Waltman, Nees Jan van Eck, and Paul Wouters has been accepted for publication in the Journal of Informetrics.
March 20, 2013. The paper Citation analysis may severely underestimate the impact of clinical research as compared to basic research by Nees Jan van Eck, Ludo Waltman, Anthony van Raan, Robert Klautz and Wilco Peul has been accepted for publication in PLoS ONE.
February 28, 2013. The science map Visualizing trends and dynamics: 30 years of scientific development by Nees Jan van Eck, Ludo Waltman, and Ferdy van Gool has been selected for display in the 9th iteration of Katy Börner's Places & Spaces: Mapping Science exhibit.
January 7, 2013. The paper Some modifications to the SNIP journal impact indicator by Ludo Waltman, Nees Jan van Eck, Thed van Leeuwen, and Martijn Visser has been published in volume 7, issue 2 of the Journal of Informetrics.
January 1, 2013. VOSviewer version 1.5.4 has been released and is available at www.vosviewer.com.
December 24, 2012. The paper An evolutionary model of price competition among spatially distributed firms by Ludo Waltman, Nees Jan van Eck, Rommert Dekker and Uzay Kaymak has been accepted for publication in Computational Economics.
December 5, 2012. VOSviewer version 1.5.3 has been released and is available at www.vosviewer.com.
November 29, 2012. The paper A new methodology for constructing a publication-level classification system of science by Ludo Waltman and Nees Jan van Eck has been published in volume 63, issue 12 of the Journal of the American Society for Information Science and Technology.
November 29, 2012. The paper The Leiden ranking 2011/2012: Data collection, indicators, and interpretation by Ludo Waltman, Clara Calero-Medina, Joost Kosten, Ed Noyons, Robbert Tijssen, Nees Jan van Eck, Thed van Leeuwen, Anthony van Raan, Martijn Visser, and Paul Wouters has been published in volume 63, issue 12 of the Journal of the American Society for Information Science and Technology.
November 20, 2012. The paper Some modifications to the SNIP journal impact indicator by Ludo Waltman, Nees Jan van Eck, Thed van Leeuwen, and Martijn Visser has been accepted for publication in the Journal of Informetrics.
November 8, 2012. The paper Source normalized indicators of citation impact: An overview of different approaches and an empirical comparison by Ludo Waltman and Nees Jan van Eck has been accepted for publication in Scientometrics.
October 18, 2012. The revised SNIP indicator has become available in Elsevier's Scopus database.
September 24, 2012. The paper Some limitations of the h-index: A commentary on Ruscio and colleagues' analysis of bibliometric indices by Ludo Waltman, Rodrigo Costas, and Nees Jan van Eck has been published in volume 10, issue 3 of Measurement: Interdisciplinary Research and Perspectives.
September 14, 2012. Calling VOSviewer with Pajek Networks, Partitions and/or Vectors has been implemented in Pajek version 3.06. Thanks again to Andrej Mrvar.
September 3, 2012. VOSviewer version 1.5.2 has been released and is available at www.vosviewer.com.
August 11, 2012. The paper An empirical analysis of the use of alphabetical authorship in scientific publishing by Ludo Waltman has been published in volume 6, issue 4 of the Journal of Informetrics.
August 2, 2012. The VOS clustering technique has been implemented in Pajek version 3.05. Thanks again to Andrej Mrvar.
July 5, 2012. The VOS mapping technique has been implemented in Pajek version 3.04. Thanks to Andrej Mrvar for his work on this.
June 13, 2012. VOSviewer version 1.5.1 has been released and is available at www.vosviewer.com.
May 26, 2012. The paper A new methodology for constructing a publication-level classification system of science by Ludo Waltman and Nees Jan van Eck has been accepted for publication in the Journal of the American Society for Information Science and Technology.
May 24, 2012. VOSviewer version 1.5.0 has been released and is available at www.vosviewer.com.
May 14, 2012. The paper A mathematical analysis of the long-run behavior of genetic algorithms for social modeling by Ludo Waltman and Nees Jan van Eck has been published in volume 16, issue 6 of Soft Computing.
March 27, 2012. The paper The Leiden Ranking 2011/2012: Data collection, indicators, and interpretation by Ludo Waltman, Clara Calero-Medina, Joost Kosten, Ed Noyons, Robbert Tijssen, Nees Jan van Eck, Thed van Leeuwen, Anthony van Raan, Martijn Visser, and Paul Wouters has been accepted for publication in the Journal of the American Society for Information Science and Technology.
March 14, 2012. VOSviewer version 1.4.3 has been released and is available at www.vosviewer.com.
February 23, 2012. VOSviewer version 1.4.2 has been released and is available at www.vosviewer.com.
January 18, 2012. VOSviewer version 1.4.1 has been released and is available at www.vosviewer.com.
December 14, 2011. The paper Universality of citation distributions revisited by Ludo Waltman, Nees Jan van Eck, and Anthony van Raan has been published in volume 63, issue 1 of the Journal of the American Society for Information Science and Technology.
December 5, 2011. The paper A mathematical analysis of the long-run behavior of genetic algorithms for social modeling by Ludo Waltman and Nees Jan van Eck has been accepted for publication in Soft Computing.
November 16, 2011. The paper Economic modeling using evolutionary algorithms: The effect of a binary encoding of strategies by Ludo Waltman, Nees Jan van Eck, Rommert Dekker, and Uzay Kaymak has been published in volume 21, issue 5 of the Journal of Evolutionary Economics.
November 3, 2011. The paper Text mining and visualization using VOSviewer by Nees Jan van Eck and Ludo Waltman has been published in volume 7, issue 3 of the ISSI Newsletter.
October 13, 2011. Today I have successfully defended my PhD thesis. The slides of my introductory presentation are available here (in Dutch).
October 13, 2011. The paper Globalisation of science in kilometres by Ludo Waltman, Robert Tijssen, and Nees Jan van Eck has been published in volume 5, issue 4 of the Journal of Informetrics.
September 13, 2011. The paper A recursive field-normalized bibliometric performance indicator: An application to the field of library and information science by Ludo Waltman, Erjia Yan, and Nees Jan van Eck has been published in volume 89, issue 1 of Scientometrics.
September 11, 2011. The paper The inconsistency of the h-index by Ludo Waltman and Nees Jan van Eck has been accepted for publication in the Journal of the American Society for Information Science and Technology.
September 10, 2011. VOSviewer version 1.4.0 has been released and is available at www.vosviewer.com.
September 1, 2011. The paper Universality of citation distributions revisited by Ludo Waltman, Nees Jan van Eck, and Anthony van Raan has been accepted for publication in the Journal of the American Society for Information Science and Technology.
August 10, 2011. The paper On the correlation between bibliometric indicators and peer review: Reply to Opthof and Leydesdorff by Ludo Waltman, Nees Jan van Eck, Thed van Leeuwen, Martijn Visser, and Anthony van Raan has been published in volume 88, issue 3 of Scientometrics.
August 1, 2011. The paper Bibliometric mapping of computer and information ethics by Richard Heersmink, Jeroen van den Hoven, Nees Jan van Eck, and Jan van den Berg has been published in volume 13, issue 3 of Ethics and Information Technology.
June 24, 2011. The paper A recursive field-normalized bibliometric performance indicator: An application to the field of library and information science by Ludo Waltman, Erjia Yan, and Nees Jan van Eck has been accepted for publication in Scientometrics.
June 13, 2011. VOSviewer version 1.3.2 has been released and is available at www.vosviewer.com.
May 30, 2011. The paper On the correlation between bibliometric indicators and peer review: Reply to Opthof and Leydesdorff by Ludo Waltman, Nees Jan van Eck, Thed van Leeuwen, Martijn Visser, and Anthony van Raan has been accepted for publication in Scientometrics.
May 17, 2011. The paper Globalisation of science in kilometres by Ludo Waltman, Robert Tijssen, and Nees Jan van Eck has been accepted for publication in the Journal of Informetrics.
May 11, 2011. The correspondence Collaborations span 1,553 kilometres by Robert Tijssen, Ludo Waltman, and Nees Jan van Eck has been published in volume 473, number 7346 of Nature. A preprint of the full paper is available in the arXiv.
May 5, 2011. The paper Text-mining and visualization using VOSviewer by Nees Jan van Eck and Ludo Waltman has been accepted for presentation at the 1st Global TechMining Conference.
April 23, 2011. The paper Towards a new crown indicator: An empirical analysis by Ludo Waltman, Nees Jan van Eck, Thed van Leeuwen, Martijn Visser, and Anthony van Raan has been published in volume 87, issue 3 of Scientometrics.
April 15, 2010. The paper Poverty research in a development policy context by Alesia Zuccala and Nees Jan van Eck has been published in volume 29, issue 3 of Development Policy Review.
April 7, 2010. The paper Bibliometric mapping of computer and information ethics by Richard Heersmink, Jeroen van den Hoven, Nees Jan van Eck, and Jan van den Berg has been accepted for publication in Ethics and Information Technology.
March 9, 2011. VOSviewer version 1.3.1 has been released and is available at www.vosviewer.com.
February 3, 2011. The paper Towards a new crown indicator: An empirical analysis by Ludo Waltman, Nees Jan van Eck, Thed van Leeuwen, Martijn Visser, and Anthony van Raan has been accepted for publication in Scientometrics.
January 24, 2011. VOSviewer version 1.3.0 has been released and is available at www.vosviewer.com.
December 24, 2010. The paper Towards a new crown indicator: Some theoretical considerations by Ludo Waltman, Nees Jan van Eck, Thed van Leeuwen, Martijn Visser, and Anthony van Raan has been published in volume 5, issue 1 of the Journal of Informetrics.
December 6, 2010. The paper On the map: Nature and Science editorials by Cathelijn Waaijer, Cornelis van Bochove, and Nees Jan van Eck has been published in volume 86, issue 1 of Scientometrics.
November 12, 2010. The paper A comparison of two techniques for bibliometric mapping: Multidimensional scaling and VOS by Nees Jan van Eck, Ludo Waltman, Rommert Dekker, and Jan van den Berg has been published in volume 61, issue 12 of the Journal of the American Society for Information Science and Technology.
November 3, 2010. The paper Poverty research in a development policy context by Alesia Zuccala and Nees Jan van Eck has been accepted for publication in Development Policy Review.
October 18, 2010. The paper Bibliometric mapping of computer and information ethics by Richard Heersmink, Jeroen van den Hoven, Nees Jan van Eck, and Jan van den Berg has been submitted.
September 23, 2010. The slides of the lecture that I gave today during the CWTS Course 'Measuring Science' are available here.
September 9, 2010. The slides of the presentation that I gave today at the 11th International Conference on Science and Technology Indicators are available here.
September 9, 2010. The paper A unified approach to mapping and clustering of bibliometric networks by Ludo Waltman, Nees Jan van Eck, and Ed Noyons has been published in volume 4, issue 4 of the Journal of Informetrics.
September 7, 2010. The paper Towards a new crown indicator: An empirical analysis by Ludo Waltman, Nees Jan van Eck, Thed van Leeuwen, Martijn Visser, and Anthony van Raan has been submitted.
August 25, 2010. The paper Towards a new crown indicator: Some theoretical considerations by Ludo Waltman, Nees Jan van Eck, Thed van Leeuwen, Martijn Visser, and Anthony van Raan has been accepted for publication in the Journal of Informetrics.
July 16, 2010. The paper A comparison of two techniques for bibliometric mapping: Multidimensional scaling and VOS by Nees Jan van Eck, Ludo Waltman, Rommert Dekker, and Jan van den Berg has been accepted for publication in the Journal of the American Society for Information Science and Technology.
July 15, 2010. The paper A unified approach to mapping and clustering of bibliometric networks by Ludo Waltman, Nees Jan van Eck, and Ed Noyons has been accepted for publication in the Journal of Informetrics.
June 15, 2010. VOSviewer version 1.2.1 has been released and is available at www.vosviewer.com.
June 15, 2010. The paper The relation between Eigenfactor, audience factor, and influence weight by Ludo Waltman and Nees Jan van Eck has been published in volume 61, issue 7 of the Journal of the American Society for Information Science and Technology.
June 13, 2010. The paper Software survey: VOSviewer, a computer program for bibliometric mapping by Nees Jan van Eck and Ludo Waltman has been published in volume 84, issue 2 of Scientometrics.
June 9, 2010. The paper Rivals for the crown: Reply to Opthof and Leydesdorff by Anthony van Raan, Thed van Leeuwen, Martijn Visser, Nees Jan van Eck, and Ludo Waltman has been published in volume 4, issue 3 of the Journal of Informetrics.
June 5, 2010. The paper A unified approach to mapping and clustering of bibliometric networks by Ludo Waltman, Nees Jan van Eck, and Ed Noyons has been submitted.
May 24, 2010. The paper Economic modeling using evolutionary algorithms: The effect of a binary encoding of strategies by Ludo Waltman, Nees Jan van Eck, Rommert Dekker, and Uzay Kaymak has been accepted for publication in the Journal of Evolutionary Economics.
May 18, 2010. VOSviewer version 1.2.0 has been released and is available at www.vosviewer.com.
March 31, 2010. The paper Rivals for the crown: Reply to Opthof and Leydesdorff by Anthony van Raan, Thed van Leeuwen, Martijn Visser, Nees Jan van Eck, and Ludo Waltman has been accepted for publication in the Journal of Informetrics.
March 15, 2010. The paper The relation between Eigenfactor, audience factor, and influence weight by Ludo Waltman and Nees Jan van Eck has been accepted for publication in the Journal of the American Society for Information Science and Technology.
March 4, 2010. The paper A comparison of two techniques for bibliometric mapping: Multidimensional scaling and VOS by Nees Jan van Eck, Ludo Waltman, Rommert Dekker, and Jan van den Berg has been submitted.
March 2, 2010. The paper Automatic term identification for bibliometric mapping by Nees Jan van Eck, Ludo Waltman, Ed Noyons, and Reindert Buter has been published in volume 82, issue 3 of Scientometrics.
February 25, 2009. The paper On the map: Nature and Science editorials by Cathelijn Waaijer, Cornelis van Bochove, and Nees Jan van Eck has been accepted for publication in Scientometrics.
February 22, 2009. The working paper On the map: Nature and Science editorials by Cathelijn Waaijer, Cornelis van Bochove, and Nees Jan van Eck has been published in the CWTS Working Paper Series and is available online.
February 9, 2009. The paper On the map: Nature and Science editorials by Cathelijn Waaijer, Cornelis van Bochove, and Nees Jan van Eck has been submitted.
January 14, 2010. The correspondence Journal Editorials give indication of driving science issues by Cathelijn Waaijer, Cornelis van Bochove, and Nees Jan van Eck has been published in volume 463, number 7278 of Nature. More information on our analysis can be found here.
January 6, 2010. VOSviewer version 1.1.0 has been released and is available at www.vosviewer.com.
December 30, 2009. The paper The relation between Eigenfactor, audience factor, and influence weight by Ludo Waltman and Nees Jan van Eck has been submitted.
December 10, 2009. The paper Software survey: VOSviewer, a computer program for bibliometric mapping by Nees Jan van Eck and Ludo Waltman has been accepted for publication in Scientometrics.
October 27, 2009. The paper A simple alternative to the h-index by Ludo Waltman and Nees Jan van Eck has been published in volume 5, issue 3 of the ISSI Newsletter.
October 8, 2009. The slides of the presentation that I gave today during the Modelling Science workshop in Amsterdam are available here.
August 26, 2009. The technical report A simple alternative to the h-index by Ludo Waltman and Nees Jan van Eck has been published in the ERIM Report Series Research in Management and is available online.
August 19, 2009. The letter to the editor On the proper understanding of the limiting behavior of generalizations of the h- and g-indices by Nees Jan van Eck and Ludo Waltman has been published in volume 3, issue 4 of the Journal of Informetrics. The letter is a rejoinder to a letter by Marek Gagolewski in which our paper Generalizing the h- and g-indices is criticized.
August 19, 2009. The paper Some comments on Egghe's derivation of the impact factor distribution by Ludo Waltman and Nees Jan van Eck has been published in volume 3, issue 4 of the Journal of Informetrics. The paper is a comment on the paper Mathematical derivation of the impact factor distribution by Leo Egghe.
July 31, 2009. The paper VOSviewer: A computer program for bibliometric mapping by Nees Jan van Eck and Ludo Waltman has been submitted.
July 17, 2009. The slides of the presentation that I gave today during the 12th International Conference on Scientometrics and Informetrics are available here.
July 15, 2009. The paper How to normalize co-occurrence data? An analysis of some well-known similarity measures by Nees Jan van Eck and Ludo Waltman has been published in volume 60, issue 8 of the Journal of the American Society for Information Science and Technology.
July 9, 2009. The new VOSviewer web site www.vosviewer.com has been launched.
June 9, 2009. The technical report Economic modeling using evolutionary algorithms: The effect of a binary encoding of strategies by Ludo Waltman, Nees Jan van Eck, Rommert Dekker, and Uzay Kaymak has been published in the ERIM Report Series Research in Management and is available online.
May 19, 2009. The paper Economic modeling using evolutionary algorithms: The effect of a binary encoding of strategies by Ludo Waltman, Nees Jan van Eck, Rommert Dekker, and Uzay Kaymak has been submitted.
May 6, 2009. The paper Some comments on Egghe's derivation of the impact factor distribution by Ludo Waltman and Nees Jan van Eck has been accepted for publication in the Journal of Informetrics. The paper is a comment on the paper Mathematical derivation of the impact factor distribution by Leo Egghe.
April 13, 2009. A map showing relations among 5000 major scientific journals has been constructed using the VOS mapping technique. The map is based on co-citation data. Click here to view the map.
March 19, 2009. The technical report Some comments on Egghe's derivation of the impact factor distribution by Ludo Waltman and Nees Jan van Eck has been published in the ERIM Report Series Research in Management and is available online.
March 19, 2009. The technical report A taxonomy of bibliometric performance indicators based on the property of consistency by Ludo Waltman and Nees Jan van Eck has been published in the ERIM Report Series Research in Management and is available online.
March 19, 2009. The technical report A mathematical analysis of the long-run behavior of genetic algorithms for social modeling by Ludo Waltman and Nees Jan van Eck has been published in the ERIM Report Series Research in Management and is available online.
March 17, 2009. The paper Some comments on Egghe's derivation of the impact factor distribution by Ludo Waltman and Nees Jan van Eck has been submitted.
February 27, 2009. The letter to the editor On the proper understanding of the limiting behavior of generalizations of the h- and g-indices by Nees Jan van Eck and Ludo Waltman has been accepted for publication in the Journal of Informetrics. The letter is a rejoinder to a letter by Marek Gagolewski in which our paper Generalizing the h- and g-indices is criticized.
February 20, 2008. The paper How to normalize co-occurrence data? An analysis of some well-known similarity measures by Nees Jan van Eck and Ludo Waltman has been accepted for publication in the Journal of the American Society for Information Science and Technology.
February 19, 2009. The technical report VOSviewer: A computer program for bibliometric mapping by Nees Jan van Eck and Ludo Waltman has been published in the ERIM Report Series Research in Management and is available online.
January 25, 2009. The paper VOSviewer: A computer program for bibliometric mapping by Nees Jan van Eck and Ludo Waltman has been submitted. VOSviewer is available here.
January 22, 2009. The technical report How to normalize co-occurrence data? An analysis of some well-known similarity measures by Nees Jan van Eck and Ludo Waltman has been published in the ERIM Report Series Research in Management and is available online.
January 7, 2009. The paper How to normalize co-occurrence data? An analysis of some well-known similarity measures by Nees Jan van Eck and Ludo Waltman has been submitted.
December 11, 2008. The paper Robust evolutionary algorithm design for socio-economic simulation: Some comments by Ludo Waltman and Nees Jan van Eck has been published in volume 33, issue 1 of Computational Economics.
December 5, 2008. The technical report Automatic term identification for bibliometric mapping by Nees Jan van Eck, Ludo Waltman, Ed Noyons, and Reindert Buter has been published in the ERIM Report Series Research in Management and is available online.
November 30, 2008. The paper Automatic term identification for bibliometric mapping by Nees Jan van Eck, Ludo Waltman, Ed Noyons, and Reindert Buter has been submitted.
November 12, 2008. The paper Some comments on the journal weighted impact factor proposed by Habibzadeh and Yadollahie by Ludo Waltman and Nees Jan van Eck has been published in volume 2, issue 4 of the Journal of Informetrics.
November 12, 2008. The paper Generalizing the h- and g-indices by Nees Jan van Eck and Ludo Waltman has been published in volume 2, issue 4 of the Journal of Informetrics.
September 18, 2008. The slides of the presentation that I gave today at the 10th International Conference on Science and Technology Indicators are available here. The maps that were shown in the presentation are available here. The VOS visualization software is available here.
September 18, 2008. The slides of the presentation that Ludo Waltman gave today at the 10th International Conference on Science and Technology Indicators are available here. The term map of the operations research field that was shown in the presentation is available here.
September 12, 2008. The technical report Generalizing the h- and g-indices by Nees Jan van Eck and Ludo Waltman has been published in the ERIM Report Series Research in Management and is available online.
September 9, 2008. The paper Generalizing the h- and g-indices by Nees Jan van Eck and Ludo Waltman has been accepted for publication in the Journal of Informetrics.
August 1, 2008. The paper Generalizing the h- and g-indices by Nees Jan van Eck and Ludo Waltman has been submitted.
July 17, 2008. The paper Appropriate similarity measures for author cocitation analysis by Nees Jan van Eck and Ludo Waltman has been published in volume 59, issue 10 of the Journal of the American Society for Information Science and Technology.
June 30, 2008. Two abstracts have been accepted for presentation at the 10th International Conference on Science and Technology Indicators. One abstract is entitled An experimental comparison of bibliometric mapping techniques and is written by Nees Jan van Eck, Ludo Waltman, Rommert Dekker, and Jan van den Berg. The other abstract is entitled Automatic term identification for bibliometric mapping and is written by Nees Jan van Eck, Ludo Waltman, Ed Noyons, and Renald Buter.
June 28, 2008. The slides of the presentation that I gave today at the 14th International Conference on Computing in Economics and Finance are available here. The slides of the presentation that Ludo Waltman gave today at the 14th International Conference on Computing in Economics and Finance are available here.
June 12, 2008. The paper Some comments on the journal weighted impact factor proposed by Habibzadeh and Yadollahie by Ludo Waltman and Nees Jan van Eck has been accepted for publication in the Journal of Informetrics. The paper is a comment on a paper by Farrokh Habibzadeh and Mahboobeh Yadollahie recently published in the Journal of Informetrics.
May 26, 2008. The paper Robust evolutionary algorithm design for socio-economic simulation: Some comments by Ludo Waltman and Nees Jan van Eck has been accepted for publication in Computational Economics. The paper is a comment on two papers by Floortje Alkemade, Han La Poutré, and Hans Amman (published in Computational Economics and Computational Intelligence) and on a correction of these papers (to be published in Computational Economics).
April 10, 2008. The paper Cluster-based visualization of concept associations by Nees Jan van Eck, Flavius Frasincar, and Dwain Chang has been accepted for presentation at the 12th International Conference on Information Visualisation to be held in London, United Kingdom on July 8-11, 2008.
March 10, 2008. The papers An algorithm for calculating the long-run behavior of genetic algorithms in economic modeling and Equilibria in first-price sealed-bid auctions of multiple heterogeneous objects: a numerical approach, both by Ludo Waltman and Nees Jan van Eck, have been accepted for presentation at the 14th International Conference on Computing in Economics and Finance to be held in Paris, France on June 26-28, 2008.
February 24, 2008. The paper Appropriate similarity measures for author cocitation analysis by Nees Jan van Eck and Ludo Waltman has been accepted for publication in the Journal of the American Society for Information Science and Technology.
February 16, 2008. A revised version of the paper Appropriate similarity measures for author cocitation analysis by Nees Jan van Eck and Ludo Waltman has been submitted to the Journal of the American Society for Information Science and Technology.
January 16, 2008. The technical report Appropriate similarity measures for author cocitation analysis by Nees Jan van Eck and Ludo Waltman has been published in the ERIM Report Series Research in Management and is available online.
December 12, 2007. The brief communication Appropriate similarity measures for author cocitation analysis by Nees Jan van Eck and Ludo Waltman has been submitted to the Journal of the American Society for Information Science and Technology.
November 20, 2007. The paper Application of reinforcement learning to the game of Othello by Nees Jan van Eck and Michiel van Wezel will be published in volume 35, issue 6 of the Computers & Operations Research.
October 15, 2007. The paper Bibliometric mapping of the computational intelligence field by Nees Jan van Eck and Ludo Waltman has been published in volume 15, issue 5 of the International Journal of Uncertainty, Fuzziness and Knowledge-Based Systems.
August 27, 2007. The brief communication Some comments on the question whether co-occurrence data should be normalized by Ludo Waltman and Nees Jan van Eck has been published in volume 58, issue 11 of the Journal of the American Society for Information Science and Technology.
June 24, 2007. The slides of the presentation Applying ideas from homogeneity analysis to visualize similarity data, which I will give at the Correspondence Analysis and Related Methods (CARME) conference on June 26, are available online. The CARME conference takes place at Erasmus University Rotterdam from July 25 to July 27.
June 7, 2007. The paper Predicting stock price movements using concept maps by Ankit Soni, Nees Jan van Eck, and Uzay Kaymak has been accepted for publication in the International Journal of Information Technology and Intelligent Computing.
June 4, 2007. A MATLAB implementation and a C implementation of VOS have been made available online. VOS is a method for visualizing similarities between objects that I developed together with Ludo Waltman. The method has been used in a number of our publications.
May 10, 2007. The technical report Bibliometric mapping of the computational intelligence field by Nees Jan van Eck and Ludo Waltman has been published in the ERIM Report Series Research in Management and is available online.
May 1, 2007. The camera-ready version of the invited paper The role of soft computing in intelligent data analysis by Rudolf Kruse, Christian Borgelt, Detlef Nauck, Nees Jan van Eck, and Matthias Steinbrecher has been completed. The paper will be published in Proceedings of the 2007 IEEE International Conference on Fuzzy Systems.
March 28, 2007. The brief communication Some comments on the question whether co-occurrence data should be normalized by Ludo Waltman and Nees Jan van Eck, which is forthcoming in the Journal of the American Society for Information Science and Technology, has been published as a technical report in the ERIM Report Series Research in Management and is available online.
March 20, 2007. The paper Bibliometric mapping of the computational intelligence field by Nees Jan van Eck and Ludo Waltman has been conditionally accepted for publication in a special issue of the International Journal of Uncertainty, Fuzziness and Knowledge-Based Systems.
March 10, 2007. I will give a presentation entitled Bibliometric mapping of the field of economics using a new visualization method at the Tinbergen Institute PhD lunch seminar on March 15. The abstract of the presentation is available here.
March 4, 2007. Loet Leydesdorff has written a reply to our brief communication Some comments on the question whether co-occurrence data should be normalized. Both our brief communication and Leydesdorff's reply are available at Leydesdorff's website.
December 31, 2006. The paper Bibliometric mapping of the computational intelligence field by Nees Jan van Eck and Ludo Waltman has been submitted for publication in a special issue of the International Journal of Uncertainty, Fuzziness and Knowledge-Based Systems. The concept (density) maps and the concept map viewer are available here.
December 22, 2006. The brief communication Some comments on the question whether co-occurrence data should be normalized by Ludo Waltman and Nees Jan van Eck has been accepted for publication in the Journal of the American Society for Information Science and Technology.
November 3, 2006. The paper Visualizing the computational intelligence field by Nees Jan van Eck, Ludo Waltman, Jan van den Berg, and Uzay Kaymak has been published in IEEE Computational Intelligence Magazine. The concept (density) maps and the concept map viewer are available here.
September 27, 2006. The extended abstract On the visualization of the soft computing knowledge domain by Nees Jan van Eck, Ludo Waltman, Jan van den Berg, and Uzay Kaymak has been published in Proceedings of the Symposium on Fuzzy Systems in Computer Science 2006.
August 22, 2006. The paper Visualizing the computational intelligence field by Nees Jan van Eck, Ludo Waltman, Jan van den Berg, and Uzay Kaymak has been submitted to IEEE Computational Intelligence Magazine.
August 19, 2006. The paper VOS: a new method for visualizing similarities between objects by Nees Jan van Eck and Ludo Waltman has been accepted for publication in Proceedings of the 30th Annual Conference of the German Classification Society.
August 17, 2006. I am back from holiday.
August 3, 2006. I am going on holiday from August 4 to August 16.
August 3, 2006. The extended abstract On the visualization of the soft computing knowledge domain by Nees Jan van Eck, Ludo Waltman, Jan van den Berg, and Uzay Kaymak has been accepted for presentation at the Symposium on Fuzzy Systems in Computer Science 2006 to be held in Magdeburg, Germany on September 27-28, 2006.
July 20, 2006. I won the best session presentation award at the 2006 IEEE World Congress on Computational Intelligence held in Vancouver, Canada, for my presentation of the paper Visualizing the WCCI 2006 knowledge domain.
June 30, 2006. The paper Application of reinforcement learning to the game of Othello by Nees Jan van Eck and Michiel van Wezel has been accepted for publication in Computers & Operations Research.
June 12, 2006. I received a travel grant award from the IEEE Computational Intelligence Society to support my travel to the 2006 IEEE World Congress on Computational Intelligence to be held in Vancouver, Canada on July 16-21, 2006.
May 31, 2006. I have completed my PhD research proposal. The proposed research is concerned with extracting and visualizing information from scientific literature.
May 16, 2006. The abstract A comparison of knowledge domain visualization approaches has been accepted for presentation in the poster session at the conference 50 Years of Econometrics to be held in Rotterdam, the Netherlands on June 9-10, 2006.
April 27, 2006. The paper VOS: a new method for visualizing similarities between objects by Nees Jan van Eck and Ludo Waltman has been submitted for publication in Proceedings of the 30th Annual Conference of the German Classification Society.
April 15, 2006. The paper Visualizing the WCCI 2006 knowledge domain by Nees Jan van Eck, Ludo Waltman, Jan van den Berg, and Uzay Kaymak has been accepted for presentation at the 2006 IEEE World Congres on Computational Intelligence to be held in Vancouver, Canada on July 16-21, 2006. The concept map based on the abstracts of the WCCI 2006 can be viewed here.
April 5, 2006. The technical report VOS: a new method for visualizing similarities between objects by Nees Jan van Eck and Ludo Waltman has been completed. The report has been published in the ERIM Report Series Research in Management and is available online.
April 1, 2006. The paper Visualizing concept associations using concept density maps by Nees Jan van Eck, Flavius Frasincar, and Jan van den Berg has been accepted for presentation at the 10th International Conference on Information Visualisation to be held in London, United Kingdom on July 5-7, 2006.
January 10, 2006. The abstract A new method for visualizing associations between concepts by Nees Jan van Eck, Ludo Waltman, and Jan van den Berg has been accepted for presentation at the 30th Annual Conference of the German Classification Society to be held in Berlin, Germany on March 8-10, 2006.
December 6, 2005. The technical report Reinforcement learning and its application to Othello by Nees Jan van Eck and Michiel van Wezel has appeared as Econometric Institute Report and is available online.
September 9, 2005. The final version of an extended abstract of the paper A novel algorithm for visualizing concept associations by Nees Jan van Eck, Ludo Waltman, and Jan van den Berg has been completed. The abstract will be published in Proceedings of the 17th Belgian-Dutch Conference on Artificial Intelligence.
August 24, 2005. I have moved from room H16-26 to room H9-7.
August 22, 2005. An extended abstract of the paper A novel algorithm for visualizing concept associations by Nees Jan van Eck, Ludo Waltman, and Jan van den Berg has been accepted for presentation in the poster session at the 17th Belgian-Dutch Conference on Artificial Intelligence.
July 11, 2005. I am back from holiday. Some pictures are available here.
June 24, 2005. I am going on holiday from June 25 to July 10.
June 14, 2005. An extended abstract of the paper A novel algorithm for visualizing concept associations by Nees Jan van Eck, Ludo Waltman, and Jan van den Berg has been submitted to the 17th Belgian-Dutch Conference on Artificial Intelligence.
June 1, 2005. I have started as a PhD student at the Faculty of Economics of Erasmus University Rotterdam. The name of my research project is Visualization of concept relations (VICORE).
May 24, 2005. I have finished the master program Informatics & Economics at Erasmus University Rotterdam.
May 15, 2005. The final version of the paper A novel algorithm for visualizing concept associations by Nees Jan van Eck, Ludo Waltman, and Jan van den Berg has been completed. The paper will be published in Proceedings of the 6th International Workshop on Theory and Applications of Knowledge Management.