George Papastefanatos

Research Associate
Institute for the Management of Information Systems
Research Center "Athena"
Artemidos 6 & Epidavrou Athens Greece


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I am a research associate at the Institute for the Management of Information Systems (IMIS) of the Research and Innovation Centre in Information, Communication and Knowledge Technologies "Athena". I am involved in several R&D EU and national projects. Check my LinkedIn profile for more info.

My research interests are in the area of big data management and analytics: more speficically I am working on issues related to the data web and linked data, data evolution and preservation, data integration, data quality, data visualization and visual analytics. I obtained my Diploma on Electrical and Computer Engineering and my PhD in Computer Science from the Department of Electrical and Computer Engineering of the National Technical University of Athens (NTUA) in 2000 and 2009, respectively.


  • 2020: New Book Published Our new book entitled "Linked Data Visualization: Techniques, Tools and Big Data" by Laura Po, Nikos Bikakis, Federico Desimoni & George Papastefanatos is published by Morgan & Claypool 2020. You can find more details in the linked data visualization website .

    A few words about the book: This book covers a wide spectrum of visualization topics, providing an overview of the recent advances in this area, focusing on techniques, tools, and use cases of visualization and visual analysis of Data (LD). It presents the core concepts related to data visualization and LD technologies, techniques employed for data visualization based on the characteristics of data, techniques for Big Data visualization, tools and use cases in the LD context, and, finally, a thorough assessment of the usability of these tools under different scenarios. It offers a complete guide to the evolution of LD visualization for interested readers from any background and empowers them to get started with the visual analysis of such data. The book can serve as a course textbook or as a primer for everyone who wants to explore and analyze LD, whether undergraduate and post-graduate students, data scientists, semantic technology developers, or UI & UX designers who wish to gain some practical experience with LD tools. Previous knowledge of Semantic Web technologies such as RDF, OWL, SPARQL, or programming skills is not required.

  • 2020: Best Paper Award: For the first time, DOLAP 2020 considered the best paper award. Our paper entitled "Hierarchical Property Set Merging for SPARQL Query Optimization" by Marios Meimaris, George Papastefanatos and Panos Vassiliadis was selected for this award.
  • 2018: Best Paper Award: Our paper entitled "RawVis: Visual Exploration over Raw Data" by Nikos Bikakis, Stavros Maroulis, George Papastefanatos, and Panos Vassiliadis was granted the ADBIS 2018 Best Paper Award.

Research Interests & Projects

  • Data Web
    • Web Data dynamics has been a primary focus of my research, involving problems related to Linked Data Evolution & Archiving, Temporal & Change Modelling, Change Propagation and Synchronization, Proactive design, and Benchmarking. I was actively involved in the DIACHRON project, which addressed many of the above issues.
    • Multidimensional modeling & Statistical Linked Data. I have coordinated , a project that makes available in the form of Linked Data, socio-economic and socio-demographic data, from the Hellenic Statistical Authority (ELSTAT).
    • Another line of ongoing work is in the area of RDF Indexing and Query Processing in RDF stores. We have developed a scalable approach for query processing of large RDF stores, based on a novel indexing technique, called Extended Characteristic Sets. See our recent vision paper.
    • Using data web technologies for creating and managing Personal dataspaces is an active research work. We have developed, a web-based, linked data enabled tool that supports collaborative management of information resources, enabling users to create and manage diverse types of resources into common spaces such as files, web documents, people, datasets and calendar events.
    • A recent project I have coordinated deals with the Semantic Representation of Legal Documents. We have developed a framework for automatic Structuring and Semantic Indexing of Legal Documents, used in the electronic library of the Greek General Secretariat of Public Revenue (in Greek).
  • Big Data Integration
    • A second area of interest concerns Entity resolution in Big Data Integration settings, such as duplicate detection and entity interlinking. I have worked on Blocking \ Meta-blocking techniques as well as on Entity Resolution Parallelization techniques for improving the performance and quality of the process. In this context, I have been involved in OpenAire project, where we have developed a scalable framework for interlinking scholarly data.
  • Data analytics
    • An active direction in my research concerns the areas of Data visualization and Visual Analytics. We have developed a visual analysis tool, used for visualization and exploration of social and political data.
    • Also, I am interested in Data Exploration techniques, with a focus on very large graph data. GraphVizDB is a tool that enables the visualization and exploration of very large graphs. 
    • I have also worked on OLAP analytics on the Web. We have developed an approach that analyzes and detects relationships in OLAP data published on the web. See our results in our paper @EDBT16.
  • Data-Centric Ecosystems, Database Quality Metrics
    • A long standing research interest is on Data-Centric Information Systems, and issues related to their schema evolution, the representation of dependencies and automatic repairing of syntactic and semantic inconsistencies due to maintenance operations. I am also interested in the evaluation of design quality metrics and the construction of design patterns for these environments. There is an UoI-IMIS joint project, called Hecataeus, which combines the representation and management of evolution processes into a powerful tool.

Here is a list of my publications and my bio.

  • 1995-2000: Undergraduate Student, National Technical University of Athens, Greece
    • Diploma Thesis: A Quality Assurance Framework for Educational Software
  • 2000 - 2008: PhD Candidate, National Technical University of Athens, Greece
    • Ph.D. Thesis: Policy Regulated Management of Schema Evolution in Database-centric Environments

Teaching Experience and Supervision

Contact Info
Institute for the Management of Information Systems
Research Center "Athena"
Artemidos 6 & Epidavrou,
Marousi 15125, Greece
tel: +30 210 6875446