16884861
Design and implementation of finite resolution crisp and fuzzy spatial objects
Uncertainty management for geometric data is currently an important problem in spatial databases, image databases, and geographic information systems. Spatial entities do not always have homogeneous interiors and sharply defined boundaries but frequently their interiors and boundaries are partially or totally indeterminate and vague. For an important kind of spatial vagueness called spatial fuzziness this paper provides a conceptual and an implementation model of fuzzy spatial objects that also incorporates fuzzy geometric union, intersection, and difference operations as well as fuzzy topological predicates. In particular, this model is not based on Euclidean space and not on an infinite-precision arithmetic which lead to lacking numerical robustness and to topological inconsistency of implementations on a computer; it rests on a finite, discrete geometric domain called grid partition which takes into account finite-precision number systems available in computers. Last but not least, this paper is a contribution to achieve a uniform treatment of vector and raster data.
12688384
Query-By-Trace: Visual Predicate Specification in Spatio-Temporal Databases
In this paper we propose a visual interface for the specification of predicates to be used in queries on spatio-temporal databases. The approach is based on a visual specification method for temporally changing spatial situations. This extends existing concepts for visual spatial query languages, which are only capable of querying static spatial situations. We outline a preliminary user interface that supports the specification on an intuitive and easily manageable level, and we describe the design of the underlying visual language. The visual notation can be used directly as a visual query interface to spatio-temporal databases, or it can provide predicate specifications that can be integrated into textual query languages leading to heterogeneous languages.
1455658
Temporal Objects for Spatio-Temporal Data Models and a Comparison of Their Representations
We present anew approach to temporal data modeling based on the very general notion of temporal object. Moreover, we propose the database embedding of temporal objects by means of the abstract data type (ADT) approach. We consider the expressiveness of different temporal database embeddings, and we discuss the combination of temporal and spatial objects into spatio-temporal objects in (relational) databases. We explain various alternatives for spatio-temporal data models and databases and compare their expressiveness.
12411101
Topological Relationships Between Complex Lines and Complex Regions
Topological relationships between spatial objects in the two-dimensional space have been investigated for a long time in a number of disciplines like artificial intelligence, cognitive science, linguistics, and robotics. In the context of spatial databases and geographical information systems, as predicates they especially support the design of suitable query languages for spatial data retrieval and analysis. But so far, they have only been defined for simplified abstractions of spatial objects like continuous lines and simple regions. With the introduction of complex spatial data types in spatial data models and extensions of commercial database systems, an issue arises regarding the design, definition, and number of topological relationships operating on these complex types. This paper first introduces a formally defined, conceptual model of general and versatile spatial data types for complex lines and complex regions. Based on the well known 9-intersection model, it then formally determines the complete set of mutually exclusive topological relationships between complex lines and complex regions. Completeness and mutual exclusion are shown by a proof technique called proof-by-constraint-and-drawing.
4468582
Genomics Algebra: A New, Integrating Data Model, Language, and Tool for Processing and Querying Genomic Information
The dramatic increase of mostly semi-structured genomic data, their heterogeneity and high variety, and the increasing complexity of biological applications and methods mean that many and very important challenges in biology are now challenges in computing and here especially in databases. In contrast to the many query-driven approaches advocated in the literature, we propose a new integrating approach that is based on two fundamental pillars. The Genomics Algebra provides an extensible set of high-level genomic data types ( GDTs) (e.g., genome, gene, chromosome, protein, nucleotide) together with a comprehensive collection of appropriate genomic functions (e.g., translate, transcribe, decode). The Unifying Database allows us to manage the semi-structured contents of publicly available genomic repositories and to transfer these data into GDT values. These values then serve as arguments of Genomics Algebra operations, which can be embedded into a DBMS query language.
8927520
Vague Spatial Data Types, Set Operations, and Predicates
Many geographical applications deal with spatial objects that cannot be adequately described by determinate, crisp concepts because of their intrinsically indeterminate and vague nature. Current geographical information systems and spatial database systems are unable to cope with this kind of data. To support such data and applications, we introduce vague spatial data types for vague points, vague lines, and vague regions. These data types cover and extend previous approaches and are part of a data model called VASA (Vague Spatial Algebra). Their formal framework is based on already existing, general exact models of crisp spatial data types, which simplifies the definition of the vague spatial model. In addition, we obtain executable specifications for the operations which can be immediately used as implementations. This paper gives a formal definition of the three vague spatial data types as well as some basic operations and predicates. A few example queries illustrate the embedding and expressiveness of these new data types in query languages.
10276591
Multiscale methods for the segmentation and reconstruction of signals and images
This paper addresses the problem of both segmenting and reconstructing a noisy signal or image. The work is motivated by large problems arising in certain scientific applications, such as medical imaging. Two objectives for a segmentation and denoising algorithm are laid out: it should be computationally efficient and capable of generating statistics for the errors in the reconstruction and estimates of the boundary locations. The starting point for the development of a suitable algorithm is a variational approach to segmentation (Shah 1992). This paper then develops a precise statistical interpretation of a one dimensional (1-D) version of this variational approach to segmentation. The 1-D algorithm that arises as a result of this analysis is computationally efficient and capable of generating error statistics. A straightforward extension of this algorithm to two dimensions would incorporate recursive procedures for computing estimates of inhomogeneous Gaussian Markov random fields. Such procedures require an unacceptably large number of operations. To meet the objective of developing a computationally efficient algorithm, the use of previously developed multiscale statistical methods is investigated. This results in the development of an algorithm for segmenting and denoising which is not only computationally efficient but also capable of generating error statistics, as desired.
14259556
SearchLight - A Lightweight Search Function for Pervasive Environments
We present a lightweight search function for physical objects in instrumented environments. Objects are tagged with optical markers which are scanned by a steerable camera and projector unit on the ceiling. The same projector can then highlight the objects when given the corresponding marker ID. The process is very robust regarding calibration, and no 3D model of the environment is needed. We discuss the scenario of finding books in a library or office environment and several extensions currently under development.