DBLab School of Computer and Electrical Engineering KDBSL NTUA
Wednesday, October 20, 2021


1. Introduction

The vast volumes of information produced nowadays, makes the handling and storing of data increasingly harder. It is obvious that the huge volumes of data do not constitute knowledge per se, but special extraction methods have to be employed in order to produce knowledge artefacts. We call these artefacts, patterns. Till now, patterns had not been treated as primary citizens in most data models. The challenge from the database perspective is to develop models and tools for storing, querying and linking patterns with the underlying data.

2. Research Issues

-Pattern Modeling.
T. Sellis, M. Terrovitis,P. Vassiliadis
({timos,mter}@dblab.ntua.gr, pvassil@cs.uoi.gr)

Patterns are usually quite heterogeneous and require ad-hoc processing techniques. So far little emphasis has been given on developing an overall integrated environment for uniformly representing and querying different types of patterns. We propose such an environments the Pattern Warehouse, constituted from the Pattern-Base and the Database modules. In the context of modelling, storing and querying we study languages for representing and managing patterns.

-Indexing Patterns and Data.
T. Sellis, M. Terrovitis,P. Vassiliadis
({timos,mter}@dblab.ntua.gr, pvassil@cs.uoi.gr)


We study ways of navigating efficiently from the pattern to the data space. We focus on indices which organize data based on the patterns that represent them. We use these indices to answer queries on the relations between the data and the patterns. Such queries enable the verification of hypothesises or even they demonstrate how properties of the patterns are reflected in the data space.

-Spatiotemporal Patterns.
T. Sellis, M. Terrovitis


Trajectories are usually represented by sample positions of the moving objects. Still, we are often interested in general properties of the trajectories, and not in exact positions. Such queries can involve topological and navigational relations between the moving objects. In this framework we study trajectories as functional patterns. We are interested in modelling and storing such patterns, as well as optimizing query execution on them. Selected References

3. Selected Publications

S. Rizzi, E. Bertino, B. Catania, M. Golfarelli, M. Halkidi, M. Terrovitis, P. Vassiliadis, M. Vazirgiannis, and E.Vrachnos. Towards a logical model for patterns. In Proc. of the 22nd International Conference on Conceptual Modeling (ER'03), Chicago Illinois, October 2003.

M. Terrovitis, P. Vassiliadis, S. Skiadopoulos, E. Bertino, B. Catania, and A. Maddalena. Modeling and Language Support for the Management of Pattern-Bases. In Proc. of the 16th International Conference on Scientific and Statistical Database Management (SSDBM'04), Santorini, Greece, 2004.

4. Funding

PANDA (Patterns for Next-Generation Database Systems), European Commission, IST programme, IST-2001-33058 , 2001-2004.

5. Contacts

Prof. Timos Sellis
Phone: +30-1-772-1601, Fax: +30-1-772-1442
e-mail: timos@dblab.ece.ntua.gr

Manolis Terrovitis
Phone: +30-1-772-1402, Fax: +30-1-772-1442
e-mail: mter@dblab.ece.ntua.gr

School of Electr. and Comp. Engineering
Computer Science Division
National Techn. Univ. of Athens
Zographou, 157 73 Athens, Greece

[ Back ]