Research team on Data & Web Mining

Latest News

  • Prof Vazirgiannis presents in the European Summer School in Information Retrieval (ESSIR) tutorial entitled "Graph-of-words: boosting text mining with graphs"

  • Παρουσίαση: Αρχειοθέτηση ιστοπεριεχομένου και διατήρηση ψηφιακής μνήμης: "η εμπειρία του ΟΠΑ"-Μ. Βαζιργιάννης, Επιστημονική Ημερίδα: Η συμβολή των οικονομικών βιβλιοθηκών στην έρευνα και στην ανάπτυξη, Τράπεζα της Ελλάδος, Παρασκευή 6 Μαρτίου 2015, Περισσότερα: εδώ.

  • Margarita Karkali defended successfully her PhD thesis “Efficient Novelty Detection in Document Streams” on 7/7/2014.


The Data & Web Mining group was founded in 1998. Since then there is a continuous line of research in the areas of data mining and machine learning. More specifically in unsupervised learning (clustering algorithms and validity measures), advanced data management and indexing (P2P systems, distributed indexing, distributed dimensionality reduction), ranking algorithms (extensions to PageRank), More recently we are working in graph mining (degeneracy based community detection and evaluation), text mining (word disambiguation for classification, graph of words), web advertising/marketing and recommendations, machine learning for graphs(kernels, node/graph embeddings).

We have introduced “Data Mining” and “Machine Learning” as taught subjects in the Greek University system syllabi. Our research group has hosted more than ten competed Ph.D. theses. See details

Our members have published chapters in books and encyclopedias, two international books and more than a hundred twenty (150) papers in international refereed journals and conferences. Also we have co-authored three patents and attracted significant R&D funding including national and international research & development projects. Members of our team have has received the ERCIM and Marie Curie EU fellowships.

Our group has co-organized the ECML PKDD 2011 conference in Athens. Members of the group participate in the editorial board of the Intelligent Data Analysis Journal and served as guest editors for special issues of the “Machine Learning” and “Data Mining & Knowledge Discovery” journals. Also co-chaired the PC committee of ECML/PKDD 2011 conference, served the Data Mining Track chair of the IEEE - ICDE 2011 conference and has participated as a conference committee member for more than forty international conferences, in the areas: Data Bases, Data Mining/Machine learning and the Web.

We have a long experience in real-world industrial level software projects in the area of Data Mining Text Mining and Web Service/commerce. The director of the group has been invited and participated in Google faculty EMEA summits in Zurich and London, in 2008, 2011 and 2012.

Currently Prof. Vazirgiannis is on leave at Ecole Polytechnique in France where he has established the “Data Science and Mining” group @ the Laboratory of Informatics

Greek Word2Vec (Greek Word Embeddings)

Check our Word2Vec embeddings for the Greek Language, based on a very large recent collection of Greek text (Greek Web). Based on the produced model, several word similarity and analogy tasks can be performed that reveal semantic and syntactic properties of Greek words.


Greek Language Resources

Capitalizing on the Greek Web content, about 20 million URIs, which consists of approximately 10 trillion characters, using state of the art technologies and open source software we produced various language resources.

It is a work in progress:

  • More info and download links here