Modeling and Querying Moving Objects in Networks

Modeling and Querying Moving Objects in Networks - Modeling...

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(*) This work was partially supported by a grant Gu 293/8-1 from the Deutsche Forschungsgemeinschaft (DFG), project “Datenbanken für bewegte Objekte” (Databases for Moving Objects). Modeling and Querying Moving Objects in Networks* Ralf Hartmut Güting Victor Teixeira de Almeida Zhiming Ding LG Datenbanksysteme für neue Anwendungen FernUniversität Hagen, D-58084 Hagen, Germany Abstract : Moving Objects Databases have become an important research issue in recent years. For modeling and querying moving objects, there exists a comprehensive framework of abstract data types to describe objects moving freely in the 2D plane, providing data types such as moving point or moving region . However, in many applications people or vehicles move along transportation net- works. It makes a lot of sense to model the network explicitly and to describe movements relative to the network rather than unconstrained space, because then it is much easier to formulate in queries relationships between moving objects and the network. Moreover, such models can be better sup- ported in indexing and query processing. In this paper, we extend the ADT approach by modeling networks explicitly and providing data types for static and moving network positions and regions. In a highway network, example entities corresponding to these data types are motels, construction areas, cars, and traffic jams. The network model is not too simplistic; it allows one to distinguish simple roads and divided highways and to describe the possible traversals of junctions precisely. The new types and operations are integrated seamlessly into the ADT framework to achieve a rela- tively simple, consistent and powerful overall model and query language for constrained and unconstrained movement. 1 Introduction The field of moving objects databases has received a lot of research interest in recent years. This tech- nology allows one to model in a database the movements of entities and to ask queries about such movements. In some cases only time-dependent locations need to be managed, leading to the moving point abstraction, in other cases also the time-dependent shape or extent is of interest and we speak of moving regions . Examples of moving points are cars, aircraft, ships, mobile phone users, terrorists, or polar bears. Examples of moving regions are hurricanes, oil spills, forest fires, armies, tribes of people in history, or the spread of vegetation or of an illness. Some of the interest is spurred by current trends in consumer electronics. Wireless networking enabled and position-aware (i.e. GPS equipped) devices such as PDAs, on-board units in vehicles, or even mobile phones have become relatively cheap and are predicted to be in widespread use in the near future. This will lead to many new kinds of applications such as location-based services. At the same time a huge volume of movement information (sometimes called trajectories) will become available and need to be managed and analyzed in database systems.
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This note was uploaded on 10/19/2009 for the course CIS 6930 taught by Professor Staff during the Fall '08 term at University of Florida.

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Modeling and Querying Moving Objects in Networks - Modeling...

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