2130066
Fuzzy topological predicates, their properties, and their integration into query languages
For a long time topological relationships between spatial objects have been a main focus of research on spatial data handling and reasoning. They have especially been integrated into query languages of spatial database systems and geographical information systems. One of their fundamental features is that they operate on spatial objects with precisely defined, sharp boundaries. But in many geometric and geographic applications there is a need to model spatial phenomena and their topological relationships rather through vague or fuzzy concepts due to indeterminate boundaries. This paper presents a model of fuzzy regions and focuses on the definition of topological predicates between them. Moreover, some properties of these predicates are shown, and we demonstrate how the predicates can be integrated into a query language.
17108573
Topological Relationships of Complex Points and Complex Regions
Topological relationships between spatial objects have been a focus of research on spatial data handling and reasoning for a long time. Especially as predicates they support the design of suitable query languages for spatial data retrieval and analysis in databases. Unfortunately, they are so far only applicable to simplified abstractions of spatial objects like single points, continuous lines, and simple regions, as they occur in systems like current geographical information systems and spatial database systems. Since these abstractions are usually not sufficient to cope with the complexity of geographic reality, their generalization is needed which especially has influence on the nature, definition, and number of their topological relationships. This paper partially closes this gap and first introduces very general spatial data types for complex points and complex regions. It then defines the corresponding complete sets of mutually exclusive, topological relationships.
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.
2300554
An abstract model of three-dimensional spatial data types
Although spatial objects of our world have an intrinsic three-dimensional (3D) nature, <i>3D data modeling</i> and <i>3D data management</i> have so far been neglected in spatial database systems and Geographical Information Systems, which map geometric data mainly to two-dimensional abstractions. But increasingly the third dimension becomes more and more relevant for application domains like pollution control, water supply, soil engineering, urban planning, and aviation. Large volumes of 3D data require a treatment in a database context for representing, querying, and manipulating them efficiently. This paper aims at investigating the complex inherent features of 3D data and presents an abstract, formal data model called <i>SPAL3D</i> <i>Spatial Algebra 3D</i>). The data model comprises a set of <i>three-dimensional spatial data types</i> together with a collection of geometric set operations.
420948
Developments in spatio-temporal query languages
Integrating spatio-temporal data as abstract data types into already existing data models is a promising approach to creating spatio-temporal query languages. In this context, an important new class of queries can be identified which is concerned with developments of spatial objects over time, that is, queries ask especially for changes in spatial relationships. Based on a definition of the notion of spatio-temporal predicate we provide a framework which allows to build more and more complex predicates starting with a small set of elementary ones. These predicates can be well used to characterize developments. We show how these concepts can be realized within the relational data model. In particular, we demonstrate how SQL can be extended to enable the querying of developments.
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.
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.
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.
14013704
Ambient Intelligence in Edutainment: Tangible Interaction with Life-Like Exhibit Guides
We present COHIBIT, an edutainment exhibit for theme parks in an ambient intelligence environment. It combines ultimate robustness and simplicity with creativity and fun. The visitors can use instrumented 3D puzzle pieces to assemble a car. The key idea of our edutainment framework is that all actions of a visitor are tracked and commented by two life-like guides. Visitors get the feeling that the anthropomorphic characters observe, follow and understand their actions and provide guidance and motivation for them. Our mixed-reality installation provides a tangible, (via the graspable car pieces), multimodal, (via the coordinated speech, gestures and body language of the virtual character team) and immersive (via the large-size projection of the life-like characters) experience for a single visitor or a group of visitors. The paper describes the context-aware behavior of the virtual guides, the domain modeling and context classification as well as the event recognition in the instrumented environment.