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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 151 (35 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.
Flattening an Object Algebra to Provide Performance
 In Fourteenth International Conference on Data Engineering
, 1998
"... Algebraic transformation and optimization techniques have been the method of choice in relational query execution, but applying them in OODBMS has been difficult due to the complexity of objectoriented query languages. This paper demonstrates that the problem can be simplified by mapping a complex ..."
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Cited by 58 (15 self)
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Algebraic transformation and optimization techniques have been the method of choice in relational query execution, but applying them in OODBMS has been difficult due to the complexity of objectoriented query languages. This paper demonstrates that the problem can be simplified by mapping a complex storage model to the flat binary model implemented by Monet, a stateoftheart database kernel. We present a generic mapping scheme to flatten data models and study the case of a straightforward objectoriented model. We show how flattening enabled us to implement a fullfledged query algebra on it, using only a very limited set of simple operations. The required primitives and query execution strategies are discussed, and their performance is evaluated on the 1GB TPCD benchmark, showing that our divideandconquer approach yields excellent results. 1 Introduction During the last decade, relational database technology has grown towards industrial maturity, and the attention of the research...
SpatioTemporal Data Handling with Constraints
, 1998
"... Most spatial information systems are limited to a fixed dimension (generally 2) which is not extensible. On the other hand, the emerging paradigm of constraint databases allows the representation of data of arbitrary dimension, together with abstract query languages. The complexity of evaluating que ..."
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Cited by 42 (6 self)
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Most spatial information systems are limited to a fixed dimension (generally 2) which is not extensible. On the other hand, the emerging paradigm of constraint databases allows the representation of data of arbitrary dimension, together with abstract query languages. The complexity of evaluating queries though might be costly if the dimension of the objects is really arbitrary. In this paper, we present a data model, based on linear constraints, dedicated to the representation and manipulation of multidimensional data. In order to preserve a low complexity for query evaluation, we restrict the orthographic dimension of an object O, defined as the dimension of the components O1 ; :::; On such that O = O1 \Theta \Delta \Delta \Delta \Theta On . This allows to process queries independently on each component, therefore achieving a satisfying tradeoff between design simplicity, expressive power of the query language and efficiency of query evaluation. We illustrate these concepts in the co...
Implementation of the ROSE Algebra: Efficient Algorithms for RealmBased Spatial Data Types
 PROC. OF THE 4TH INTL. SYMPOSIUM ON LARGE SPATIAL DATABASES
, 1995
"... The ROSE algebra, defined earlier, is a system of spatial data types for use in spatial database systems. It offers data types to represent points, lines, and regions in the plane together with a comprehensive set of operations; semantics of types and operations have been formally defined. Values ..."
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Cited by 37 (14 self)
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The ROSE algebra, defined earlier, is a system of spatial data types for use in spatial database systems. It offers data types to represent points, lines, and regions in the plane together with a comprehensive set of operations; semantics of types and operations have been formally defined. Values of these data types have a quite general structure, e.g. an object of type regions may consist of several polygons with holes. All ROSE objects are realmbased which means all points and vertices of objects lie on an integer grid and no two distinct line segments of any two objects intersect in their interior. In this paper we describe the implementation of the ROSE algebra, providing data structures for the types and new realmbased geometric algorithms for the operations. The main techniques used are (parallel) traversal of objects, planesweep, and graph algorithms. All algorithms are analyzed with respect to their worst case time and space requirements. Due to the realm properties, these algorithms are relatively simple, efficient, and numerically completely robust. All data structures and algorithms have indeed been implemented in the ROSE system; the Modula2 source code is freely available from the authors for study or use.
Requirements, Definitions and Notations for Spatiotemporal Application Environments
"... Modeling spatiotemporal applications is a complex task, involving intricate issues, such as the representation of objects'position in time, and spatial attributes that change values depending on specific locations in time periods. Due to this complexity, the analysis of users' requirementsas the fi ..."
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Cited by 26 (8 self)
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Modeling spatiotemporal applications is a complex task, involving intricate issues, such as the representation of objects'position in time, and spatial attributes that change values depending on specific locations in time periods. Due to this complexity, the analysis of users' requirementsas the first phase of an application development methodologyis often neglected, focusing, mainly, on physical design aspects. In this paper, we address the set of spatial, temporal and spatiotemporal concepts as they are drawn from users' needs. The goal is to support the developer's better understanding about spatiotemporal applications, by providing the concepts and the notations needed in such environments; these concepts, will later be translated into specific constructs and implementation issues. More specifically, space, spatial objects, spatial attributes, fields, time and models of time are presented and then combined to accommodate spatiotemporal peculiarities, resulting into the new, spatiotemporal, concepts of snapshots, changes, and versions of objects and maps, motion and phenomena. Examples taken from two real largescale applications show the necessity and adequacy of the presented concepts.
Spatial Databases, The Final Frontier
, 1995
"... This paper is divided into two parts. In Section 1 we discuss five different geomatic data models. All of them are intentional, i.e. they give a finite representation of the mostly infinite and even nonenumerable 2 set of points of the spatial objects that are described by the database. In the Ras ..."
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Cited by 22 (1 self)
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This paper is divided into two parts. In Section 1 we discuss five different geomatic data models. All of them are intentional, i.e. they give a finite representation of the mostly infinite and even nonenumerable 2 set of points of the spatial objects that are described by the database. In the Raster Model an object is given by a finite number of its points. These points are equally distributed following an easy geometric pattern, which is normally a square. In the Spaghetti Model an object is intentionally deduced from its contour, which is a polyline. The Peano Model also uses a finite number of objectpoints, but here these points are distributed nonuniformally, according to the form of the object. This distribution method is based on the wellknown Peano curve. In the Polynomial Model we use a calculus, extended with comparisons between polynomials. In the PLAModel, finally, only some kind of topological information is handled without dealing with the exact position and form of the spatial objects. In Section 2 we try to focus on the typical geomatic operations and we introduce different kinds of spatial queries. Therefore we generalize the wellknown concept of genericity of Chandra and Harel [Cha80]. A taxonomy of genericityclasses is given. We end with investigating two of these classes more deeply: the isometrygeneric queries and the topologygeneric queries. On many occasions we will introduce open problems, open areas or topics that have to be studied. We are convinced that a lot of research has to be done in the field of geomatic data types and geomatic operations and we hope that this text can motivate some of the young and intelligent researchers to pay more attention in the future to this unexplored forest that is irrigated by three main rivers: geo...
SQLST: A SpatioTemporal Data Model and Query Language
 Language,” Proceedings of the 19th International Conference on Conceptual Modeling, (ER’00
, 2000
"... In this paper, we propose a query language and data model for spatiotemporal information, including objects of timechanging geometry. ..."
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Cited by 21 (3 self)
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In this paper, we propose a query language and data model for spatiotemporal information, including objects of timechanging geometry.
An Extended Algebra for Constraint Databases
 IEEE Transactions on Knowledge and Data Engineering
, 1999
"... Constraint relational databases use constraints to both model and query data. A constraint relation contains a finite set of generalized tuples. Each generalized tuple is represented by a conjunction of constraints on a given logical theory and, depending on the logical theory and the specific conju ..."
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Cited by 20 (3 self)
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Constraint relational databases use constraints to both model and query data. A constraint relation contains a finite set of generalized tuples. Each generalized tuple is represented by a conjunction of constraints on a given logical theory and, depending on the logical theory and the specific conjunction of constraints, it may possibly represent an infinite set of relational tuples. For their characteristics, constraint databases are well suited to model multidimensional and structured data, like spatial and temporal data. The definition of an algebra for constraint relational databases is important in order to make constraint databases a practical technology. In this paper, we extend the previously defined constraint algebra (called generalized relational algebra). First, we show that the relational model is not the only possible semantic reference model for constraint relational databases and we show how constraint relations can be interpreted under the nested relational model. Then...
Logical Data Modeling of SpatioTemporal Applications: Definitions and a Model
 IDEAS, International Database Engineering and Applications Symposium
, 1998
"... Dealing with spatiotemporal applications at the logical phase of database design reveals a set of data peculiarities which the already existing models can not serve satisfactorily. In this paper, the ontologies of a spatiotemporal environment namely the basic concepts of objects, attributes and rel ..."
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Cited by 13 (3 self)
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Dealing with spatiotemporal applications at the logical phase of database design reveals a set of data peculiarities which the already existing models can not serve satisfactorily. In this paper, the ontologies of a spatiotemporal environment namely the basic concepts of objects, attributes and relationships with spatial and temporal extent, as well as operations on them are defined. Based on these, specifications of modeling tools for the design of spatiotemporal information at the logical phase are given. A formal, yet practical, SpatioTemporal Relational data Model (STRM) is presented as part of a full automatable application design methodology; it provides a small set of representational constructs (relations, layers, virtual layers, object classes, and constraintsall with spatial and temporal extent) on top of wellestablished models. The power of modeling and easeofuse of the discussed approach is demonstrated by an example taken from a real application. 1 Introduction The...
Data models and query languages for spatial databases
 Data Knowledge Engineering
, 1998
"... The main purpose of this paper is to investigate the characteristics that distinguish spatial databases systems from traditional ones. Hereto, we give an overview of some wellknown data models and query languages of spatial database systems. We also investigate the concept of genericity, as introdu ..."
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Cited by 10 (0 self)
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The main purpose of this paper is to investigate the characteristics that distinguish spatial databases systems from traditional ones. Hereto, we give an overview of some wellknown data models and query languages of spatial database systems. We also investigate the concept of genericity, as introduced by Chandra and Harel for classical databases [6], for spatial databases. Paredaens, Van den Bussche and Van Gucht [34] have shown that the concept of genericity breaks up in a hierarchy of genericity classes. In this respect, we classify data models and query languages according to the type of generic operations they are designed to support [33]. 1