Distributed Systems Research

Department of Informatics and Telecommunications
University of Athens

The Distributed Systems Research Group at UoA investigates topics in the areas of distributed systems, networking, mobile computing, and digital preservation. We are particularly interested in building large reliable systems using inexpensive, unreliable, and mutually suspicious nodes. Such systems are essential for problems where participants cannot individually afford a solution and do not trust third parties to provide the solution.

Research Projects   |   People   |   Publications   |   Undergraduate and Master's thesis topics   |   Funding Sources   |  

Research Projects

Some of our current projects include:

  • PPP (Protecting and Preserving Human Knowledge for Posterity): Several tens of exabytes of human knowledge are generated in digital form every year. This project aims to investigate, understand, design, and build preservation systems for digital human knowledge that are both secure and reliable. A key challenge is to understand the salient characteristics of important human knowledge, i.e., data whose preservation is deemed valuable. Some data (academic journals) is static. Some data (online news sites) undergoes frequent changes. Some data (large scientific data collections) is so large in volume, one cannot make many "backup" copies easily to preserve it. Still other data (medical data) is sensitive and needs to be preserved in a manner that respects individual privacy. This project investigates this large spectrum of data and the challenges in building preservation systems for this data.
  • BFT in the Wild: Byzantine Fault Tolerant Systems (BFT) are considered state of the art technology for building reliable distributed systems capable of withstanding arbitrary, albeit limited in number, malicious and faulty behaviors of participating nodes, but have yet to see wide deployment in real-world systems. This project aims to understand the feasibility of applying BFT technqiues to real-world systems. One main thrust of this work is to take a real application and try to "BFT-ize" it. That is, design, implement, and test real-world applications using BFT technologies. Our application muses include digital preservation and distributed electronic voting.
  • Nefeli: This project investigates algorithms and mechanisms for efficient allocation, deployment, and management of computing resources in clouds. A main thrust of the project has been the construction of Nefeli, virtual infrastructure gateway capable of handling diverse workloads of jobs in cloud environments. Users provide hints to Nefeli for the handling of their workload jobs while remaining agnostic to and being relieved of dealing with low-level details of cloud internals. At the same time, Nefeli is able to adapt cloud resource assignment as users' workloads change in nature, while achieving significant improvement in response time and energy consumption.
  • FINER: This project investigates the development and evaluation via real pilot studies of an Internet-voting system that is distributed at multiple levels of operation including the cryptographic, network, storage, and human (administrative) levels. The project has built the world's first suite of state-of-the-art end-to-end verifiable, distributed internet voting systems with no single point of failure (besides setup). The systems allow voters to verify their vote was tallied-as-intended without the assistance of special software or trusted devices, and external auditors to verify the correction of the election process. Additionally, the systems allow voters to delegate auditing to a third party auditor, without sacrificing their privacy. An earlier version of the systems has been used to conduct exit polls at three large voting sites for two national-level elections and is being adopted for use by the largest civil union of workers in Greece, consisting of over a half million members.

  • Current and Affiliated Lab Members:

    • Prof. Mema Roussopoulos

    • Nikos Chondros, PhD student.
    • Panagiotis Diamantopoulous, Master's student.
    • Michalis Konstantopoulos.
    • Stathis (Sotirios-Efstathios) Maneas, Master's student.
    • Evaggelos Papastavros, Master's student.
    • Christos Patsonakis, PhD student.
    • Vassilis Poulimenos.


    • Konstantinos Kokordelis.
    • Stelios Stylianou.
    • Konstantinos Tsakalozos.

    Master's and Undergraduate Thesis topics

    Selected Publications


    We gratefully acknowledge the support of the European Research Council, which is funding activities of our group via a European Starting Grant (no 279237) from the European Community's Seventh Framework Programme. We also gratefully acknowledge funding via a Greek Research and Technology "Aristeia" (Excellence) award.