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A Foundation for Representing and Querying Moving Objects
, 2000
"... Spatiotemporal databases deal with geometries changing over time. The goal of our work is to provide a DBMS data model and query language capable of handling such timedependent geometries, including those changing continuously which describe moving objects. Two fundamental abstractions are moving ..."
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Cited by 197 (38 self)
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Spatiotemporal databases deal with geometries changing over time. The goal of our work is to provide a DBMS data model and query language capable of handling such timedependent geometries, including those changing continuously which describe moving objects. Two fundamental abstractions are moving point and moving region, describing objects for which only the timedependent position, or position and extent, are of interest, respectively. We propose to represent such timedependent geometries as attribute data types with suitable operations, that is, to provide an abstract data type extension to a DBMS data model and query language. This paper presents a design of such a system of abstract data types. It turns out that besides the main types of interest, moving point and moving region, a relatively large number of auxiliary data types is needed. For example, one needs a line type to represent the projection of a moving point into the plane, or a "moving real" to represent the timedependent distance of two moving points. It then becomes crucial to achieve (i) orthogonality in the design of the type system, i.e., type constructors can be applied uniformly, (ii) genericity and consistency of operations, i.e., operations range over as many types as possible and behave consistently, and (iii) closure and consistency between structure and operations of nontemporal and related temporal types. Satisfying these goals leads to a simple and expressive system of abstract data types that may be integrated into a query language to yield apowerful language for querying spatiotemporal data, including moving objects. The paper formally defines the types and operations, offers detailed insight into the considerations that went into the design, and exempli es the use of the abstract data types using SQL. The paper o ers a precise and conceptually clean foundation for implementing a spatiotemporal DBMS extension.
SpatioTemporal Data Types: An Approach to Modeling and Querying Moving Objects in Databases
, 1999
"... Spatiotemporal databases deal with geometries changing over time. In general, geometries cannot only change in discrete steps, but continuously, and we are talking about moving objects. If only the position in space of an object is relevant, then moving point is a basic abstraction; if also the ext ..."
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Cited by 169 (38 self)
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Spatiotemporal databases deal with geometries changing over time. In general, geometries cannot only change in discrete steps, but continuously, and we are talking about moving objects. If only the position in space of an object is relevant, then moving point is a basic abstraction; if also the extent is of interest, then the moving region abstraction captures moving as well as growing or shrinking regions. We propose a new line of research where moving points and moving regions are viewed as threedimensional (2D space + time) or higherdimensional entities whose structure and behavior is captured by modeling them as abstract data types. Such types can be integrated as base (attribute) data types into relational, objectoriented, or other DBMS data models; they can be implemented as data blades, cartridges, etc. for extensible DBMSs. We expect these spatiotemporal data types to play a similarly fundamental role for spatiotemporal databases as spatial data types have played for sp...
A Data Model and Data Structures for Moving Objects Databases
, 1999
"... We consider spatiotemporal databases supporting spatial objects with continuously changing position and extent, termed moving objects databases. We formally define a data model for such databases that includes complex evolving spatial structures such as line networks or multicomponent regions w ..."
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Cited by 150 (30 self)
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We consider spatiotemporal databases supporting spatial objects with continuously changing position and extent, termed moving objects databases. We formally define a data model for such databases that includes complex evolving spatial structures such as line networks or multicomponent regions with holes. The data model is given as a collection of data types and operations which can be plugged as attribute types into any DBMS data model (e.g. relational, or objectoriented) to obtain a complete model and query language. A particular novel concept is the sliced representation which represents a temporal development as a set of units, where unit types for spatial and other data types represent certain "simple" functions of time. We also show how the model can be mapped into concrete physical data structures in a DBMS environment. 1 Introduction A wide and increasing range of database applications has to deal with spatial objects whose position and/or extent changes over time...
Backtracking Algorithms for Disjunctions of Temporal Constraints
 Artificial Intelligence
, 1998
"... We extend the framework of simple temporal problems studied originally by Dechter, Meiri and Pearl to consider constraints of the form x1 \Gamma y1 r1 : : : xn \Gamma yn rn , where x1 : : : xn ; y1 : : : yn are variables ranging over the real numbers, r1 : : : rn are real constants, and n 1. W ..."
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Cited by 117 (2 self)
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We extend the framework of simple temporal problems studied originally by Dechter, Meiri and Pearl to consider constraints of the form x1 \Gamma y1 r1 : : : xn \Gamma yn rn , where x1 : : : xn ; y1 : : : yn are variables ranging over the real numbers, r1 : : : rn are real constants, and n 1. We have implemented four progressively more efficient algorithms for the consistency checking problem for this class of temporal constraints. We have partially ordered those algorithms according to the number of visited search nodes and the number of performed consistency checks. Finally, we have carried out a series of experimental results on the location of the hard region. The results show that hard problems occur at a critical value of the ratio of disjunctions to variables. This value is between 6 and 7. Introduction Reasoning with temporal constraints has been a hot research topic for the last fifteen years. The importance of this problem has been demonstrated in many areas of artifici...
A spatiotemporal model and language for moving objects on road networks
 In Proc. SSTD
, 2001
"... Abstract. Moving object databases are becoming more popular due to the increasing number of application domains that deal with moving entities and need to pose queries. So far implementations of such systems have been rather weak and certainly not at industrial strength level. In this paper we defin ..."
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Cited by 67 (1 self)
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Abstract. Moving object databases are becoming more popular due to the increasing number of application domains that deal with moving entities and need to pose queries. So far implementations of such systems have been rather weak and certainly not at industrial strength level. In this paper we define a concise data model and a set of powerful query predicates for moving objects. Moreover, we propose an implementation design based on offtheshelf industrial solutions enhancing thus the applicability and robustness of our approach.
Making space for time: issues in spacetime data representation
 GeoInformatica
, 2001
"... Even with much activity over the past decade, including organized efforts on both sides of the Atlantic, the representation of both space and time in digital databases is still problematic and functional spacetime systems have not gone beyond the limited prototype stage. Why is this the case? Why d ..."
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Cited by 54 (1 self)
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Even with much activity over the past decade, including organized efforts on both sides of the Atlantic, the representation of both space and time in digital databases is still problematic and functional spacetime systems have not gone beyond the limited prototype stage. Why is this the case? Why did it take twenty years from the ®rst GIS for the for representation and analysis in the temporal, as well as the spatial dimension, to begin? I explore the answers to these questions by giving a historical overview of the development of spacetime representation in the geographic information systems and database communities and a review of the most recent research. Within the context of this perspective, I also question what seems to be a spirit of selfaccusation in which the lack of functional spacetime systems has been discussed in the literature and in meetings of GIS researchers. I close by offering my own interpretation of current research issues on spacetime data models and languages.
Modeling and Querying Moving Objects in Networks
 VLDB J
, 2004
"... 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. ..."
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Cited by 48 (11 self)
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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 networks.
Algorithms for Moving Objects Databases
"... Whereas earlier work on spatiotemporal databases generally focused on geometries changing in discrete steps, the emerging area of moving objects databases supports geometries changing continuously. Two important abstractions are moving point and moving region, modeling objects for which only the ti ..."
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Cited by 46 (12 self)
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Whereas earlier work on spatiotemporal databases generally focused on geometries changing in discrete steps, the emerging area of moving objects databases supports geometries changing continuously. Two important abstractions are moving point and moving region, modeling objects for which only the timedependent position, or also the shape and extent are relevant, respectively. Examples of the first kind of moving entity are all kinds of vehicles, aircraft, people, or animals; of the latter hurricanes, forest res, forest growth, or oil spills in the sea. The goal is to develop data models and query languages as well as DBMS implementations supporting such entities, enabling new kinds of database applications. In earlier work we have proposed an approach based on abstract data types. Hence, moving point or moving region are viewed as data types with suitable operations. For example, a moving point might be projected into the plane, yielding a curve, or a moving region be mapped to a function describing the development of its size, yielding a realvalued function. A careful design of a system of types and operations (an algebra) has been presented, emphasizing completeness, closure, consistency and genericity. This design was given at an abstract level, defining, for example, geometries in terms of infinite point sets. In the next step, a discrete model was presented, o ering nite representations and data structures for all the types of the abstract model. The present paper provides the final step towards implementation by studying and developing systematically algorithms for (a large subset of) the operations. Some of them are relatively straightforward; others are quite complex. Algorithms are meant to be used in a database context; we also address...
A Geometric Framework for Specifying Spatiotemporal Objects
 In Proc. 6th Int. Workshop on Temporal Representation and Reasoning (TIME
, 1999
"... We present a framework for specifying spatiotemporal objects using spatial and temporal objects, and a geometric transformation. We define a number of classes of spatiotemporal objects and study their closure properties. 1 Introduction Many natural or manmade phenomena have both a spatial and a t ..."
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Cited by 42 (4 self)
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We present a framework for specifying spatiotemporal objects using spatial and temporal objects, and a geometric transformation. We define a number of classes of spatiotemporal objects and study their closure properties. 1 Introduction Many natural or manmade phenomena have both a spatial and a temporal extent. Consider for example, a forest fire or property histories in a city. To store information about such phenomena in a database one needs appropriate data modeling constructs. We claim that a new concept, spatiotemporal object, is necessary. In this paper, we introduce a very general framework for specifying spatiotemporal objects. To define a spatiotemporal object we need a spatial object, a temporal object, and a continuous geometric transformation (specified using a parametric representation) that determines the image of the spatial object at different time instants belonging to the temporal object. In this framework, a number of classes of spatiotemporal objects arise quite ...
Abstract and discrete modeling of spatiotemporal data types
 Geoinformatica
, 1999
"... Spatiotemporal databases deal with geometries changing over time. In general, geometries cannot only change in discrete steps, but continuously, and we are talking about moving objects. If only the position in space of an object i s relevant, then moving point is a basic abstraction; if also the e ..."
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Cited by 40 (10 self)
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Spatiotemporal databases deal with geometries changing over time. In general, geometries cannot only change in discrete steps, but continuously, and we are talking about moving objects. If only the position in space of an object i s relevant, then moving point is a basic abstraction; if also the extent is of interest, then the moving region abstraction captures moving as well as growing or shrinking regions. We propose a new line of research where moving points and moving regions are viewed as threedimensional (2D space + time) or higherdimensional entities whose structure and behavior is captured by modeling them as abstract data types. Such types can be integrated as base (attribute) data types into relational, objectoriented, or other DBMS data models; they can be implemented as data blades, cartridges, etc. for extensible DBMSs. We expect these spatiotemporal data types to play a similarly fundamental role for spatiotemporal databases as spatial data types have played for spatial databases. In this paper we consider the need for modeling spatiotemporal data types on two different levels of abstraction. 1