News

Research Interests

I am currently a postdoc with Dan Suciu at the University of Washington, focusing on provenance and causality. I am currently working on extending the capabilities of database systems to support business decisions and strategy planning queries, which commonly involve optimization problems over large datasets.

I enjoy problems that challenge my theoretical thinking, and combine elements from different areas. In general my research derives methods and techniques from database systems, graph and approximation algorithms, distributed algorithms and analysis of distributed systems, probabilistic inference, and query processing.

Education

University of California Berkeley

August 2003 - August 2009: Ph.D in Computer Science
Advisors: Joseph Hellerstein and Carlos Guestrin

University of California Berkeley

December 2005: M.S. in Computer Science

National Technical University of Athens

September 1998 - June 2003: B.S. in Electrical Engineering and Computer Science
Advisor: Timos Sellis

CV: [pdf]

Current Projects

Causality Causality in Databases
When queries return unexpected results, users require explanations for their observations. In this project we explore what constitutes a cause for a query answer, or non-answer, and augment databases with support for causal queries. We demonstrate how causality can be used to provide explanations, as well as identify and correct data errors in a process called post-factum data cleaning.

RDM Reverse Data Management
Reverse Data Management encompasses an array of problems in database research where an action needs to be performed on the input data, on behalf of desired outcomes in the output data. Some examples include updates through views, data generation, data cleaning and repair. Today, as increasingly more of the available data is derived from other data, there is an increased need to be able to modify the input in order to achieve a desired effect on the output, motivating a systematic study of RDM.

Tiresias The Tiresias System
The goal of this project is to seamlessly integrate databases with constrained problem solving in a fully-fledged system. We are building a system that allows the user to specify an optimization problem over their data declaratively. The system then translates the declarative input into a mixed integer program that is sent to a dedicated solver.