I am a senior researcher at the Computing Systems Laboratory of the Department of Electrical and Computer Engineering of the National Technical University of Athens (NTUA). I received my Diploma in Electrical and Computer Engineering in 2005 and my Ph.D. in 2011 from NTUA. My research lies in the field of Large Scale Distributed Systems, Peer - to - Peer Technologies and Cloud Computing.

Large Scale Distributed Systems

Peer - to - Peer Technologies

Grid/Cloud Computing

ARCOMEM - From Collect-All Archives to Community Memories - Leveraging the Wisdom of the Crowds for Intelligent Preservation, FP7-ICT-2009.4.1.

GREDIA - Grid Enabled Access to Rich media Content (FP6-34363): The vision of the project is the creation of a reliable Grid application development platform with high level support for the design, implementation and operational deployment of secure Grid business applications and the development of a generic Grid middleware for accessing distributed, annotated content.

GreeD (GSRT, EHG-89): The project's objective is the development of a system for the retrieval of heterogeneous content concerning the history and culture of Greek Diaspora. The project will develop a search engine, which will operate on a grid infrastructure based on Web Services technology. Searching will be supported by a meta-thesaurus, which will constitute a conceptual super-structure containing the concepts relevant to the providers' content, as well as the relations holding between them.

HiPPIS: Concept hierarchies greatly help in the organization and reuse of information. Multidimensional, hierarchy-organized data are widely used in a variety of applications, such as data warehousing, mining network data, etc. In the HiPPIS (Hierarchical Peer-to-Peer Indexing System) project, we investigate methods for efficiently storing and querying multidimensional data organized into concept hierarchies and dispersed over a network.

Brown Dwarf: The Brown Dwarf is a distributed system designed to efficiently store, query and update multidimensional data over a Peer-to-Peer overlay. It manages to distribute a highly effective centralized structure among peers on-the-fly. Both point and aggregate queries are then naturally answered on-line through cooperating nodes that hold parts of a fully or partially materialized data cube. Updates are also performed on-line, eliminating the usually costly over-night process.

GridTorrent: GridTorrent is an implementation of the popular BitTorrent protocol designed to interface and integrate with well-defined and deployed Data Grid components and protocols (e.g. GridFTP, RLS). Just like BitTorrent, GridTorrent is based on peer-to-peer techniques, that allow clients to download files from multiple sources while uploading them to other users at the same time, rather than obtaining them from a central server.

International Journals

K. Doka and D. Tsoumakos and N. Koziris: Brown Dwarf: A Fully-Distributed, Fault-Tolerant Data Warehousing System Journal of Parallel and Distributed Computing, Accepted manuscript, 2011.

K. Doka and D. Tsoumakos and N. Koziris: Online Querying of d-Dimensional Hierarchies. Journal of Parallel and Distributed Computing, 71(3): pp. 424-437, 2011, doi:10.1016/j.jpdc.2010.10.005.

A. Assiki and K. Doka and I. Konstantinou and A. Zissimos and D. Tsoumakos and N. Koziris and P. Tsanakas: A Grid middleware for data management exploiting Peer-to-Peer techniques.. In FUTURE GENERATION COMPUTER SYSTEMS, 25 (2009) 426-435.

International Conferences

K. Doka and D. Tsoumakos and N. Koziris:KANIS: Preserving k-Anonymity Over Distributed Data. To appear in the Proceedings of the 5th International Workshop on Personalized Access, Profile Management and Context Awareness in Databases (PersDB 2011), Seatle, WA, September 2, 2011.

K. Doka and D. Tsoumakos and N. Koziris: Brown Dwarf: A P2P Data-Warehousing System. In Proceedings of the 19th ACM International Conference on Information and Knowledge Management (CIKM' 10 demo track), Toronto, Canada, October 26-30, 2010.

K. Doka and D. Tsoumakos and N. Koziris: Distributing the Power of OLAP. In Proceedings of the 19th ACM International Symposium on High Performance Distributed Computing (HPDC'10), Chicago, Illinois, USA, June 23-25, 2010.

K. Doka and D. Tsoumakos and N. Koziris: Efficient Updates for a Shared Nothing Analytics Platform. In Proceedings of the International Workshop on Massive Data Analytics over the Cloud (MDAC '10 - in conjunction with WWW 2010), Raleigh, North Carolina, 26 April 2010.

A. Zisimos and K. Doka and A. Chazapis and D. Tsoumakos and N. Koziris: Optimizing Data Management in Grid Environments. In Proceedings of the 11th International Symposium on Distributed Objects, Middleware, and Applications (DOA'09), Vilamoura, Algarve-Portugal, Nov 01 - 03, 2009.

K. Doka and A. Asiki and D. Tsoumakos and N. Koziris: Online Querying of Concept Hierarchies in P2P Systems. In Proceedings of the 16th International Conference on Cooperative Information Systems (CooPIS'08), Monterrey, Mexico, 12-14 November 2008.

K. Doka and D. Tsoumakos and N. Koziris: HiPPIS: An Online P2P System for Efficient Lookups on d-Dimensional Hierarchies. In Proceedings of the 10th International Workshop on Web Information and Data Management (WIDM'08), Napa Valley, California, 26-30 October 2008.

A. Asiki and K. Doka and D. Tsoumakos and N. Koziris: Support for Concept Hierarchies in DHTs. In Proceedings of 8th International Conference on Peer-to-Peer Computing (P2P'08), Aachen University , Germany , 8-11 September 2008.

A. Asiki and K. Doka and I. Konstantinou and A. Zissimos and N. Koziris: A Distributed Architecture for Multi-Dimensional Indexing and Data Retrieval in Grid Environments. In Proceedings of the Cracow 2007 Grid Workshop (CGW'07), Krakow, Poland, October 16-17, 2007.

I. Konstantinou and K. Doka and A. Asiki, A. Zissimos and N. Koziris: Gredia Middleware Architecture. In Proceedings of the Cracow 2007 Grid Workshop (CGW'07), Krakow, Poland, October 16-17, 2007.

A. Zissimos and K. Doka and A. Chazapis and N. Koziris: GridTorrent: Optimizing data transfers in the Grid with collaborative sharing. In Proceedings of the 11th Panhellenic Conference on Informatics (PCI'07), Patras, Greece, May 2007.