East European Symposium on Advanced Data Bases and Information Systems (ADBIS) (Varna 2007)

IFIP TC8 International Conference on Enterprise Information Systems (CONFESIS) (Beijing 2007)

International Workshop on "Dependability and Security in e-Government" (DeSeGov) (Vienna 2007)

International Conference on Enterprise Information Systems (ICEIS) (Madeira 2007)

International Symposium on Intelligent and Distributed Computing (IDC) (Craiova 2007)

ADBIS Workshop on Data Mining and Knowledge Discovery (Varna 2007)

Balkan Conference in Informatics (BCI) (Sofia 2007)

International Symposium on Spatiotemporal Databases (SSTD) (Boston MA 2007)

ACM International Conference on Knowledge Discovery and Data Mining (SIGKDD) (San Jose 2007)

ACM Workshop on Advances in Geographical Information Systems (ACM-GIS) (Arlington 2006)

Workshop on Spatiotemporal Database Management (STDBM) (Seoul 2006)

International Baltic Conference on Databases and Information Systems (Baltic DB&IS) (Vilnius 2006)

IFIP Conference on Artificial Intelligence Applications and Innovations (AIAI) (Athens 2006)

International Conference on Extending Database Conference (EDBT) (Munich 2006 )

European Conference on Machine Learning and European Conference on Principles and Practice of Knowledge Discovery (ECML/PKDD) (Berlin 2006)

International Conference on Somputer Systems and Technologies (CompSysTech) (Veliko Tarnovo/Bulgaria 2006)

IASTED International Conference on Databases and Applications (DBA) (Innsruck 2006)

International Conference on Information and Knowledge Management (CIKM) (Arlington 2006)

International Conference on Hybrid Information Technology (ICHIT) (Cheju Island/Korea 2006)

ACM Workshop on Advances in Geographical Information Systems (ACM-GIS) (Bremen 2005, )

East European Symposium on Advanced Data Bases and Information Systems (ADBIS) (Tallinn 2005)

International Conference on Enterprise Information Systems (ICEIS) (Miami 2005)

ACM Workshop on Data Engineering for Wireless and Mobile Access (MobiDE) (Baltimore 2005)

International Conference on Data Warehousing and Knowledge Discovery (DaWaK) (Copenhagen 2005)

International Conference on Information Systems Development: Methods and Tools, Theory and Practice (ISD) (Karlstad 2005)

ADBIS Workshop on Data Mining and Knowledge Discovery (Tallinn 2005)

IASTED International Conference on Databases and Applications (DBA) (Innsruck 2005)

International Conference on Somputer Systems and Technologies (CompSysTech) (Varna 2005)

International Conference of the Information Resources Management Association (IRMA) (San Jose 2005)

Balkan Conference in Informatics (BCI) (Ohrid 2005)

International Conference on Database Systems for Advanced Applications (DASFAA) (Beijing 2005)

IADIS Database Systems Conference (DS) in conjunction with the Virtual Multiconference on Computer Science and Information Systems (2005)

"Web Mining and Web Usage Analysis" (Seattle WA, 2004) in conjunction with the ACM SIGKDD Conference on Knowledge Discovery in Databases (KDD)

Information Systems Modeling Conference (ISM) (Roznov pod Radhostem 2004)

ACM Workshop on Advances in Geographical Information Systems (ACM-GIS) Washington DC 2004)

East European Symposium on Advanced Data Bases and Information Systems (ADBIS) (Budapest 2004)

Workshop on Spatiotemporal Database Management (STDBM) (Toronto 2004)

International Conference on Enterprise Information Systems (ICEIS) (Porto 2004)

International Conference on Information Systems and Innovative Technologies in Agriculture, Food and Environment (Thessaloniki 2004)

International Conference of the Information Resources Management Association (IRMA) (New Orleans 2004)

International Conference on Information Systems Development: Methods and Tools, Theory and Practice (ISD) (Vilnius 2004)

Workshop on Distributed Data and Structures (WDAS) (Laussane 2004)

International Conference on Extending Database Conference (EDBT) (Heraklion 2004)

Minitrack on Internet Data Management in conjunction with the 18th ACM Symposium on Applied Computing (SAC) (Nicosia 2004)

Information Systems Modeling Conference (ISM) (Brno 2003)

ACM Workshop on Advances in Geographical Information Systems (ACM-GIS) (New Orleans LO 2003)

East European Symposium on Advanced Data Bases and Information Systems (ADBIS) (Dresden 2003)

International Conference on Enterprise Information Systems (ICEIS) (Angers 2003)

IEEE International Conference on Data Engineering - Demo Session (ICDE) (Bangalore 2003)

Atlantic Conference on Web Intelligence (AWIC) (Madrid 2003)

International Workshop WebKDD on "Web Mining for Usage Patterns and User Profile" (Edmonton, Alberta 2002)

Information Systems Modeling Conference (ISM) (Roznov pod Radhostem 2002)

East European Symposium on Advanced Data Bases and Information Systems (ADBIS) (Bratislava 2002)

International Conference on Extending Database Conference (EDBT) (Prague 2002)

International Conference on Enterprise Information Systems (ICEIS) (Ciudad Real 2002)

Workshop on Distributed Data and Structures (WDAS) (Paris 2002)

International Workshop on Web Analytics in conjunction with International Conference on Data Mining (SDM) (Arlington VA 2002)

International Workshop WebKDD on "Mining Log Data across All Customer Touchpoints" (San Francisco CA, 2001)

Information Systems Modeling Conference (ISM) (Hradec 2001)

East European Symposium on Advanced Data Bases and Information Systems (ADBIS) (Vilnius 2001)

International Symposium on Spatiotemporal Databases (SSTD) (Los Angeles CA 2001)

International Workshop on Multimedia Information Retrieval (MIR) in conjunction with the International Conference on Multimedia (ACM MM) (Ottawa, Ontario 2001)

International Conference on Very Large Data Bases (VLDB) (Rome 2001)

Information Systems Modeling Conference (ISM) (Brno 1999, Brno 2000)

ACM Workshop on Advances in Geographical Information Systems (ACM-GIS) (Washington DC 2000)

International Conference on Extending Database Conference (EDBT) (Konstanz 2000)

ACM SIGIR Conference ( Athens 2000), Organizing Committee Member

East European Symposium on Advanced Data Bases and Information Systems (ADBIS) (Prague 2000)

International Workshop on Advanced Spatial Data Management (ASDM) in conjunction with the International Conference on Database and Expert Systems Applications (DEXA) (London 2000)

Ph.D. Consortium in conjunction with EDBT'2000 (Konstanz 2000)

Information Systems Modeling Conference (ISM) (Brno 1999)

ACM Workshop on Advances in Geographical Information Systems (ACM-GIS) (Kansas City MI 1999)

Workshop on Spatiotemporal Database Management (STDBM) (Edinburgh 1999)

ACM SIGMOD Conference (Philadelphia PA, 1999)

East European Symposium on Advanced Data Bases and Information Systems (ADBIS) (Maribor 1999)

International Workshop on Similarity Search (IWOSS) in conjunction with the International Conference on Database and Expert Systems Applications (DEXA) ( Florence 1999)

International Symposium on Spatial Databases (SSD) ( Hong Kong 1999)

ACM Workshop on Advances in Geographical Information Systems (ACM-GIS) (Washington DC 1998)

East European Symposium on Advanced Data Bases and Information Systems (ADBIS) (Poznan 1998)

ACM Workshop on Advances in Geographical Information Systems (ACM-GIS) (Las Vegas NV 1997)

International Conference for Geographical Information Systems in Urban, Environmental and Regional Planning (Athens 1997)

East European Symposium on Advanced Data Bases and Information Systems (ADBIS) (St. Petersburg 1997)

International Conference for Geographical Information Systems in Urban, Environmental and Regional Planning (Samos 1996)

Annual Computer Theory and Informatics Conference (Pinehurst NC, 1994)

Hellenic Computer Science Conference (Patra 2007)

Greek Symposium in Databases-HSDM (Athens 2005)

Hellenic Conference in Computer Science in Education (Thessaloniki 2004)

Greek Symposium in Databases-HSDM (Athens 2004)

Greek Symposium in Databases-HSDM (Athens 2003)

Greek Symposium in Databases-HSDM (Athens 2002)

Hellenic Conference in Computer Science in Education (Thessaloniki 2000)

Hellenic Computer Science Conference (Ioannina 1999)

Hellenic Conference in new Information Technologies (Athens 1998)

Hellenic Computer Science Conference (Athens 1997)

Ph.D. Consortium, 5th Hellenic Conference in Computer Science (Athens 1995)

Hellenic Computer Science Conference (Patra 1993)

Hellenic Computer Science Conference (Athens 1991)

Two-day Conference in "Databases" in memory of G.Kollias, Helexpo and Helenic Computer Science Conference (Thessaloniki 1990), Chair of Scientific and Organization Committee

Hellenic Computer Science Conference (Thessaloniki 1988)

One day Conference in "Use of Computer Science in Local Self-Administration, Helexpo (Thessaloniki 1984), Member of the Organization Committee