ERCIM News No.29 - April 1997

Chorochronos - A Research Network for Spatiotemporal Database Systems

by Timos Sellis

CHOROCHRONOS is a three-year research program funded by the European Commission under the Training and Mobility for Researchers (TMR) program. The project commenced in August 1996. A major goal of Training and Mobility for Researchers networks is to provide an excellent environment for the training of young researchers. The CHOROCHRONOS sites will offer, during the three years of the project, grants for a total of about 30 years to young researchers having interests in topics related to Spatial and Temporal Database Systems.

Spatial and temporal databases have been important sub-areas of database research for a long time. Researchers in both areas have always felt that there are important connections in the problems addressed by each area, and the techniques and tools utilized for their solution. There are many publications in temporal databases which conclude with the phrase the ideas in this paper can be extended to spatial data management. But up to now, little has been done, particularly in Europe, for the systematic interaction and synergy of these two areas so that the respective claims can be formally verified, refuted or appropriately qualified. CHOROCHRONOS aims to achieve exactly this kind of interaction and synergy between European researchers. The main objective of CHOROCHRONOS is to allow European researchers working on spatial and temporal databases to achieve a higher understanding of each other's work, integrate their results and methodologies, and advance the state of the art in this area through an intensive three-year research programme. This will culminate in the design and partial implementation of an architecture for Spatiotemporal Database Systems (STDBMS). CHOROCHRONOS will cover issues related to the ontology, structure and representation for space and time, models and languages for STDBMS, graphical user interfaces for spatiotemporal information, query processing algorithms, storage structures and indexing techniques for spatiotemporal databases, and, based on results on these issues, will propose a reference architecture for Spatiotemporal Database Systems. The participants will also cooperate, through intensive workshops, with researchers from other disciplines who are dealing with temporal and spatial information in their research, and would benefit from the development of an STDBMS. Finally, the network will stimulate training and mobility of young researchers working in the areas of spatial and temporal databases through an extensive training program.


All participating nodes have an expertise either in spatial or in temporal database systems, with a long and reputable research record. The groups in Athens, Thessaloniki and L'Aquila have specialized on spatial data indexing techniques and the analysis of spatial data structures. INRIA and Hagen have a strong background in spatial query languages, graphical interfaces and visual spatial query languages, multi-scale representation and transportation networks, while ETH has a long experience with efficient algorithms, system architectures and implementation. Vienna has been involved for a long time with the definition of ontologies for space and time and formal models of spatio-temporal geographic objects, while NTUA has a similar experience with spatial knowledge representation and reasoning. In the field of temporal databases, Aalborg has been involved in building methodologies for temporal database design, as well as temporal data models and query languages; similarly the UMIST team has been working on temporal relational database implementations and more recently on temporal object databases, temporal data mining, building ontologies for conceptual models and temporal relational constraint databases. To complement these activities in temporal databases, the group at Milano has been working on temporal reasoning, time granularity and on enhancing existing commercial database management systems with functionalities for time management.

Potential Applications

Spatiotemporal databases are an important technology for a number of applications, such as Geographic Information Systems, remote sensing, environmental information systems and CAD/CAM, and developments in this area are expected to be highly relevant to industry. This is demonstrated by the number of industrial cooperations that nodes of the network already have. Several of these companies have already expressed their strong support for CHOROCHRONOS, and it is expected that industrial cooperations will continue and will be strengthened during the lifetime of this network.

Training Aspects

A total of 366 man-months of young researcher (ie doctoral and post-doctoral researchers) effort will be funded by CHOROCHRONOS allowing talented young researchers (especially recent PhDs) to remain in Europe and contribute to the research area of spatiotemporal databases. At the same time it will allow young researchers from network nodes to visit other nodes, learn from their expertise and transfer this knowledge back to their home nodes.

Participants of the CHOROCHRONOS network are National Technical University of Athens, Greece (coordinator); Aalborg University, Denmark; FernUniversität Hagen, Germany; Università di L'Aquila, Italy; University of Manchester Institute of Science and Technology (UMIST), UK; Politecnico di Milano, Italy; INRIA, France; Aristotle Univ. of Thessaloniki, Greece; Technical University of Vienna, Austria; and SGFI-ETH, Switzerland.

For more information about CHOROCHRONOS and the positions available at various network nodes, please visit the CHOROCHRONOS home page

Please contact:
Timos Sellis ­ National Technical University of Athens
Tel: +30 1 7721601

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