PeopleofSuperintelligence

Researcher

Constantine Spyropoulos

Also known as Constantine D. Spyropoulos

Constantine Spyropoulos is an AI researcher whose work includes machine learning, email filtering and online content analysis. He earned degrees in applied mathematics and computing, joined Demokritos's AI team in 1984, and founded SKEL in 1989. His work includes a 2000 study of email spam filters and a 2001 paper on machine learning for named-entity recognition; he became an ECCAI Fellow in 2002. He co-founded i-sieve in 2004 and directed Demokritos's Institute of Informatics and Telecommunications from 2004 to 2013. As of October 2026, he is a Collaborating Researcher in Content Analysis and Knowledge Technologies at IIT of NCSR Demokritos.

Now at
National Centre for Scientific Research Demokritos
Works
89
Citations
3,451
h-index
24
Badges

Publication numbers from OpenAlex, as of 19 October 2026.

Timeline

  1. 1974–1975

    Degrees in mathematics and computing

    In 1974, he earns a BSc in Applied Mathematics from the University of Ioannina; in 1975, he earns an MSc in Computing with Applications at Loughborough University of Technology.

  2. 1979–1984

    Engineering for the armed forces

    From 1979 to 1984, he works as a software engineer consultant in the R&D departments of the Greek Air Forces and Army on Command & Control Information Systems.

  3. 1984–1989

    Joining Demokritos's AI team

    In 1984, he joins the Artificial Intelligence team at Demokritos. He founds the Software and Knowledge Engineering Laboratory (SKEL) in 1989.

  4. 2000–2001

    Spam filtering and machine learning

    In 2000, he coauthors a study that compares Naive Bayesian filtering with a keyword-based spam filter on personal email messages. In 2001, he coauthors a paper on using machine learning to maintain rule-based named-entity recognition and classification systems.

  5. 2002

    An ECCAI fellowship

    In 2002, he becomes a Fellow of the European Coordination Committee of Artificial Intelligence (ECCAI).

  6. 2004

    Co-founding i-sieve

    In 2004, he co-founds i-sieve to explore online content-analysis technology developed at SKEL.

  7. 2004–2013

    Directing the institute

    From 2004 to 2013, he directs the Institute of Informatics and Telecommunications at NCSR Demokritos.

  8. As of October 2026

    Collaborating researcher at Demokritos

    As of October 2026, he is a Collaborating Researcher in Content Analysis and Knowledge Technologies at the Institute of Informatics and Telecommunications of NCSR Demokritos.

Career

  1. Since 1984National Centre for Scientific Research DemokritosTeam member, Founder
  2. From 2004i-sieveCo-founder
  3. 1991–2023National Centre of Scientific Research "Demokritos"
  4. 1979–1984Hellenic Air ForceSoftware engineer consultant
  5. 1979–1984Hellenic ArmySoftware engineer consultant

Education

  1. 1975Loughborough University of TechnologyMSc in Computing with Applications
  2. 1974University of IoanninaBSc in Applied Mathematics

From the biography and OpenAlex affiliations (the years of papers that list the organization), so some years are approximate.

Most-cited works

  1. An evaluation of Naive Bayesian anti-spam filtering2000 · 532 citations
  2. An experimental comparison of naive Bayesian and keyword-based anti-spam filtering with personal e-mail messages2000 · International ACM SIGIR Conference on Research and Development in Information Retrieval (SIGIR) · 465 citations
  3. Web Usage Mining as a Tool for Personalization: A Survey2003 · User Modeling and User-Adapted Interaction · 348 citations
  4. Learning to Filter Spam E-Mail: A Comparison of a Naive Bayesian and a Memory-Based Approach2000 · 292 citations
  5. A Memory-Based Approach to Anti-Spam Filtering for Mailing Lists2003 · Information Retrieval · 207 citations

From OpenAlex, as of 19 October 2026.

  1. Google had the most people shaping AI every year from 2014 to 2025Our estimates of which organizations employed the most people shaping AI from 1961 to 2025, with a year-by-year chart.
  2. The United States employs an estimated 53% of people in our data with a known employment countryOur estimates of where AI careers are concentrated now and how countries’ shares of dated positions changed over time.
  3. 47% of living people in our data with known birth and employment countries work outside their birth countryOur estimate of cross-border careers in AI, from country of birth and the country of each current organization.
  4. More people shaping AI studied at Massachusetts Institute of Technology than at any other institutionOur estimates of where the people shaping AI studied and where their careers led, from education records in cited biographies.

Colleagues

People with dated positions at the same organization in the same years.

Sources and credits

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  1. Dr Constantine D. Spyropoulos users.iit.demokritos.gr. Checked 19 October 2026.
  2. Our History skel.ai. Checked 19 October 2026.
  3. An Experimental Comparison of Naive Bayesian and Keyword-Based Anti-Spam Filtering with Personal E-mail Messages arxiv.org. Checked 19 October 2026.
  4. Publications | Institute of Informatics & Telecommunications iit.demokritos.gr. Checked 19 October 2026.
  5. Awards | European Association for Artificial Intelligence eurai.org. Checked 19 October 2026.
  6. Constantine Spyropoulos - Institute of Informatics & Telecommunications iit.demokritos.gr. Checked 19 October 2026.