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39
Time Responsive Indexing Schemes for Moving Points
- In Proc. Workshop on Algorithms and Data Structures
, 2001
"... We develop new indexing schemes for storing a set of points in one or two dimensions, each moving along a linear trajectory, so that a range query at a given future time t q can be answered efficiently. The novel feature of our indexing schemes is that the number of I/Os required to answer a quer ..."
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We develop new indexing schemes for storing a set of points in one or two dimensions, each moving along a linear trajectory, so that a range query at a given future time t q can be answered efficiently. The novel feature of our indexing schemes is that the number of I/Os required to answer a query depends not only on the size of the data set and on the number of points in the answer but also on the difference between t q and the current time; queries close to the current time are answered fast, while queries that are far away in the future or in the past may take more time. Center for Geometric Computing, Department of Computer Science, Duke University, Durham, NC 27708, USA. Supported in part by Army Research Office MURI grant DAAH04-96-1-0013, by a Sloan fellowship, by NSF grants EIA--9870724, EIA--997287, and CCR--9732787, and by grant from the U.S.-Israeli Binational Science Foundation. Email: pankaj@cs.duke.edu. y Center for Geometric Computing, Department of Computer Sci...
A Universal Abstract Model for Future Movements of Moving Objects
- In AGILE International Conference on Geographical Information Systems
, 2007
"... Summary. Recently, with the advances in mobile technology and emerging mobile applications, moving objects databases have become the focus of much research. A number of models have been proposed to handle the continuously changing geometries and positions of moving objects. While most of these model ..."
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Summary. Recently, with the advances in mobile technology and emerging mobile applications, moving objects databases have become the focus of much research. A number of models have been proposed to handle the continuously changing geometries and positions of moving objects. While most of these models focus on managing the historical and current motion of moving objects, only a few of them have been proposed to deal with their future movements. Due to the complexity of handling the uncertainty aspect associated with future movements, these models are often restricted to a specific type of constrained movement and tailored to a certain application domain by integrating specific prediction techniques. These predictions are often based only on the past and current movements and neglect external domainspecific information which may significantly affect the future movements of moving objects. In this paper, we emphasize the separation of moving object models and prediction methods and propose a universal abstract model for future movements of moving objects. This abstract model serves as a conceptual basis for all future movement models as well as poses object requirements for the output of all prediction methods. 1
Modeling Historical and Future Movements of Spatio-Temporal Objects in Moving Objects Databases
"... Spatio-temporal databases deal with geometries changing over time. In general, geometries do not only change discretely but continuously; hence we are dealing with moving objects. In the past, a few moving object data models and query languages have been proposed. Each of them supports either histor ..."
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Spatio-temporal databases deal with geometries changing over time. In general, geometries do not only change discretely but continuously; hence we are dealing with moving objects. In the past, a few moving object data models and query languages have been proposed. Each of them supports either historical movements or future movements but not both together. Consequently, queries that start in the past and extend into the future cannot be supported. To model both historical and future movements of an object, two separate concepts with different properties are required, and extra attention is necessary to avoid their conflicts. Furthermore, current definitions of moving objects are too general and vague. It is unclear how a moving object is allowed to move through space and time. For instance, the continuity or discontinuity of motion is not specified. In this paper, we propose a new moving object data model called Balloon model which provides integrated support for both historical and future movements of moving objects. As part of the model, we provide formal definitions of moving objects with respect to their past and future movements. All kinds of queries including past queries, future queries, and queries that start in the past and end in the future are supported in our model. 1.
Uncertainty in Spatiotemporal Databases
- Proc. 2nd Biennial Int. Conf. on Advances in Information Systems (ADVIS
, 2002
"... Several different models for spatial indeterminacy have been presented. ..."
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Several different models for spatial indeterminacy have been presented.
Toward Spatiotemporal Patterns
"... Existing spatiotemporal data models and query languages offer only basic support to query changes of data. In particular, although these systems often allow the formulation of queries that ask for changes at particular time points, they fall short of expressing queries for sequences of such changes. ..."
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Existing spatiotemporal data models and query languages offer only basic support to query changes of data. In particular, although these systems often allow the formulation of queries that ask for changes at particular time points, they fall short of expressing queries for sequences of such changes. In this chapter we propose the concept of spatiotemporal patterns as a systematic and scalable concept to query developments of objects and their relationships. Based on our previous work on spatiotemporal predicates, we outline the design of spatiotemporal patterns as a query mechanism to characterize complex object behaviors in space and time. We will not present a fully-fledged design. Instead, we will focus on deriving constraints that will allow spatiotemporal patterns to become well-designed composable abstractions that can be smoothly integrated into spatiotemporal query languages. Spatiotemporal patterns can be applied in many different areas of science, for example, in geosciences, geophysics, meteorology, ecology, and environmental studies. Since users in these areas typically do not have extended formal computer training, it is often difficult for them to use advanced query languages. A visual notation for spatiotemporal patterns can help solving this problem. In particular, since spatial objects and their relationships have a natural graphical representation, a visual notation can express relationships in many cases implicitly where textual notations require the explicit application of operations and predicates. Based on our work on the visualization of spatiotemporal predicates, we will sketch the design of a visual language to formulate spatiotemporal patterns.
Chorochronos: research on spatiotemporal database systems
- Proceedings of the 10th International Workshop on Database and Expert Systems Applications, DEXA’99, 452–456
, 1999
"... Spatiotemporal database management systems can be-come an enabling technology for important applications such as Geographic Information Systems (GIS), environ-mental information systems, and multimedia. In this paper we address research issues in spatiotemporal databases, by providing an analysis of ..."
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Spatiotemporal database management systems can be-come an enabling technology for important applications such as Geographic Information Systems (GIS), environ-mental information systems, and multimedia. In this paper we address research issues in spatiotemporal databases, by providing an analysis of the challenges set, the prob-lems encountered, as well as the proposed solutions and the envisioned research areas open to investigation in the EU funded project CHOROCHRONOS. 1.
Spatiotemporal Data Modeling and Management: A Survey
- In Proceedings of the 36 th International Conference on Technology of Object-Oriented Languages and Systems
, 2000
"... Many data objects in the real world have attributes about location and time. Such spatiotemporal objects can be found in applications such as Geographic Information Systems (CIS), environmental data management and multimedia databases. Traditional relational database technology is not suitable for m ..."
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Many data objects in the real world have attributes about location and time. Such spatiotemporal objects can be found in applications such as Geographic Information Systems (CIS), environmental data management and multimedia databases. Traditional relational database technology is not suitable for managing spatiotemporal data, which are multi-dimensional with complex structures and behaviours. Spatiotemporal data can only be managed by new generation of data management technologies such as object-oriented and object-relational databases. In this paper, we present a comprehensive survey covering aspects from fundamental user requirements for spatiotemporal applications, spatiotemporal object modelling, object storage structures and techniques for manipulation of spatiotemporal objects such as multidimensional indexing, data structures, query evaluation strategies and architectures for Spatiotemporal Database Management Systems. 1.
Modeling Historical and Future Spatio-Temporal Relationships of Moving Objects in Databases
"... Abstract. Moving object databases have recently found large interest in the database community, geographical information systems, and geosciences. So far, moving object models have focused exclusively either on past or future movements. The so-called Balloon Model is the first attempt to treat past ..."
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Abstract. Moving object databases have recently found large interest in the database community, geographical information systems, and geosciences. So far, moving object models have focused exclusively either on past or future movements. The so-called Balloon Model is the first attempt to treat past and future movements of moving objects in a consistent and integrated manner. Based on a new set of spatio-temporal data types and operations as well as former research, in this paper, we propose a design of spatio-temporal predicates on Balloon objects. These predicates explore the topological relationships of Balloon objects over time and take into account both past and future movements. We present new kinds of queries to demonstrate the use of these predicates. 1
An Object-Relational Approach to the Representation of Multi-granular Spatio-Temporal Data
"... Abstract. The notion of spatio-temporal multi-granularity is fundamental when modeling objects in GIS applications in that it supports the representation of the temporal evolutions of these objects. Concepts and issues in multi-granular spatio-temporal representations have been widely investigated b ..."
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Abstract. The notion of spatio-temporal multi-granularity is fundamental when modeling objects in GIS applications in that it supports the representation of the temporal evolutions of these objects. Concepts and issues in multi-granular spatio-temporal representations have been widely investigated by the research community. However, despite the large number of theoretical investigations, no comprehensive approaches, have been proposed dealing with the representation of multi-granular spatio-temporal objects in commercially available DBMSs. The goal of the work that we report in this paper is to address this gap. To achieve it, the paper first introduces an object-relational model based on OpenGis specifications described in SQL3. Several extensions are developed in order to improve the semantics and behavior for spatio-temporal data types introducing an approach to represent the temporal dimension in this model and the multi-representation of spatio-temporal granularities. 1
