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  • 1
    Monographie ausleihbar
    Monographie ausleihbar
    Foundations of multidimensional and metric data structures (2006)
    Amsterdam [u.a.] : Elsevier
    Details Verfügbarkeit
    Signatur: 18/M 06.0569
    Beschreibung / Inhaltsverzeichnis: Multidimensional data is data that exists and changes in more than one dimension, by time, or spatially, or both, sometimes dynamically. Thinkhere of tracking hurricane data in order to project the storm's path,for just one example. As spatial and other multidimensional datastructures become increasingly important for the applications in gameprogramming, data mining, bioinformatics, and many other areas--including astronomy, geographic information systems, physics,etc., the need for a comprehensive book on the subject is paramount.
    Materialart: Monographie ausleihbar
    Seiten: xxvii, 993 S.
    ISBN: 0123694469
    Klassifikation:
    Informatik
    Standort: Lesesaal
    Zweigbibliothek: GFZ Bibliothek
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  • 2
    Digitale Medien
    Digitale Medien
    MAGELLAN: Map Acquisition of GEographic Labels by Legend ANalysis (1998)
    Springer
    International journal on document analysis and recognition 1 (1998), S. 89-101 
    Details
    ISSN: 1433-2825
    Schlagwort(e): Key words:Map recognition – Document analysis – Object recognition – Image databases – Geographic information systems (GIS)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik
    Notizen: Abstract. A system named MAGELLAN (denoting Map Acquisition of GEographic Labels by Legend ANalysis) is described that utilizes the symbolic knowledge found in the legend of the map to drive geographic symbol (or label) recognition. MAGELLAN first scans the geographic symbol layer(s) of the map. The legend of the map is located and segmented. The geographic symbols (i.e., labels) are identified, and their semantic meaning is attached. An initial training set library is constructed based on this information. The training set library is subsequently used to classify geographic symbols in input maps using statistical pattern recognition. User interaction is required at first to assist in constructing the training set library to account for variability in the symbols. The training set library is built dynamically by entering only instances that add information to it. MAGELLAN then proceeds to identify the geographic symbols in the input maps automatically. MAGELLAN can be fine-tuned by the user to suit specific needs. Recognition rates of over 93% were achieved in an experimental study on a large amount of data.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s100320050009
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  • 3
    Digitale Medien
    Digitale Medien
    A comparison of the space requirements of multi-dimensional quadtree-based file structures (1989)
    Springer
    The visual computer 5 (1989), S. 349-359 
    Details
    ISSN: 1432-2315
    Schlagwort(e): Image databases ; Quadtrees ; Octrees ; Image compression
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik
    Notizen: Abstract A comparison is made of the space requirements of pointer and a number of pointer-less implementations of multidimensional quadtree-based file structures. The database is assumed to be static. In order to make the comparison realistic, considerations such as computer byte sizes are taken into account, and fields are constrained to start on bit and byte boundaries where appropriate. In many practical cases, the pointer quadtree requires less space than the pointer-less quadtree. This effect is more pronounced for octrees and data of higher dimension. Empirical data from a cartographic batabase are used to support the analysis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01999102
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  • 4
    Digitale Medien
    Digitale Medien
    Vertex representations and their applications in computer graphics (1998)
    Springer
    The visual computer 14 (1998), S. 240-256 
    Details
    ISSN: 1432-2315
    Schlagwort(e): Key words: Shape representation ; Orthogonal polygons ; Vertex lists ; Constructive solid geometry (CSG) ; Solid modeling
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s003710050138
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  • 5
    Digitale Medien
    Digitale Medien
    Approximating CSG trees of moving objects (1990)
    Springer
    The visual computer 6 (1990), S. 182-209 
    Details
    ISSN: 1432-2315
    Schlagwort(e): CSG ; Solid modeling ; Bintrees ; Hierarchical data structures ; Time ; Motion ; Interference detection
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik
    Notizen: Abstract A discussion of the relationship between two solid representation schemes is presented: CSG trees and recursive spatial subdivision exemplified by the bintree, a generalization of the quadtree and octree. Detailed algorithms are developed and analyzed for evaluating CSG trees by bintree conversion. These techniques are shown to enable the addition of the time dimension and motion to the approximate analysis of CSG trees. This facilitates the solution of problems such as static and dynamic interference detection. A technique for projecting across any dimension is also shown. For “well-behaved” CSG trees the execution time of the conversion algorithm is directly related to the spatial complexity of the object represented by the CSG tree (i.e., as the resolution increases, it is asymptotically proportional to the number of bintree nodes and does not depend on the size or form of the CSG tree representation). The set of well-behaved CSG trees include all trees that define multidimensional polyhedra in a manner that does not give rise to tangential intersections at CSG tree nodes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02341044
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  • 6
    Digitale Medien
    Digitale Medien
    Planning a time-minimal motion among moving obstacles (1993)
    Springer
    Algorithmica 10 (1993), S. 41-63 
    Details
    ISSN: 1432-0541
    Schlagwort(e): Time-varying environments ; Visibility graphs ; Accessibility graphs ; Motion planning
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik , Mathematik
    Notizen: Abstract Motion planning for a point robot is studied in a time-varying environment. Each obstacle is a convex polygon that moves in a fixed direction at a constant speed. The point to be reached (referred to as the destination point) also moves along a known trajectory. The concept of “accessibility” from a point to a moving object is introduced, and is used to define a graph on a set of moving obstacles. If the point robot is able to move faster than any of the obstacles, then the graph exhibits an important property: a time-minimal motion is given as a sequence of edges in the graph. An algorithm is described for generating a time-minimal motion and its execution time is analyzed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01908631
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  • 7
    Digitale Medien
    Digitale Medien
    Linear-time border-tracing algorithms for quadtrees (1992)
    Springer
    Algorithmica 8 (1992), S. 39-54 
    Details
    ISSN: 1432-0541
    Schlagwort(e): Quadtrees ; Chain codes ; Worst-case analysis ; Connected component labeling
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik , Mathematik
    Notizen: Abstract In applications where the quadtree is used as an underlying object representation, a number of basic operations are implemented as a trace along the border of the object's region. A technique is presented that determines a way to shift any given scene (as well as its quadtree), so that the border of all the objects in the scene can be traversed in time proportional to the length of all the borders in the scene (or the number of blocks when the scene is represented as a quadtree). This determination is shown to be performed in time proportional to the length of all the borders in the scene. This allows the direct translation of a number of chain-code algorithms into quadtree algorithms without loss of asymptotic worst-case efficiency. This results in improved worst-case analyses of algorithms that convert chain codes into quadtrees and that perform connected component labeling of images represented as quadtrees.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01758835
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  • 8
    Digitale Medien
    Digitale Medien
    Integrating symbolic images into a multimedia database system using classification and abstraction approaches (1998)
    Springer
    The VLDB journal 7 (1998), S. 253-274 
    Details
    ISSN: 0949-877X
    Schlagwort(e): Key words:Symbolic-image databases – Multimedia databases – Retrieval by content – Spatial databases – Image indexing – Query optimization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik
    Notizen: Abstract. Symbolic images are composed of a finite set of symbols that have a semantic meaning. Examples of symbolic images include maps (where the semantic meaning of the symbols is given in the legend), engineering drawings, and floor plans. Two approaches for supporting queries on symbolic-image databases that are based on image content are studied. The classification approach preprocesses all symbolic images and attaches a semantic classification and an associated certainty factor to each object that it finds in the image. The abstraction approach describes each object in the symbolic image by using a vector consisting of the values of some of its features (e.g., shape, genus, etc.). The approaches differ in the way in which responses to queries are computed. In the classification approach, images are retrieved on the basis of whether or not they contain objects that have the same classification as the objects in the query. On the other hand, in the abstraction approach, retrieval is on the basis of similarity of feature vector values of these objects. Methods of integrating these two approaches into a relational multimedia database management system so that symbolic images can be stored and retrieved based on their content are described. Schema definitions and indices that support query specifications involving spatial as well as contextual constraints are presented. Spatial constraints may be based on both locational information (e.g., distance) and relational information (e.g., north of). Different strategies for image retrieval for a number of typical queries using these approaches are described. Estimated costs are derived for these strategies. Results are reported of a comparative study of the two approaches in terms of image insertion time, storage space, retrieval accuracy, and retrieval time.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s007780050068
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  • 9
    Digitale Medien
    Digitale Medien
    Efficient Window Block Retrieval in Quadtree-Based Spatial Databases (1997)
    Springer
    Geoinformatica 1 (1997), S. 59-91 
    Details
    ISSN: 1573-7624
    Schlagwort(e): databases ; design of algorithms ; data structures ; spatial databases ; range query ; quadtree space decomposition ; active border ; window block retrieval ; clipping
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geographie
    Notizen: Abstract An algorithm is presented to answer window queries in a quadtree-based spatial database environment by retrieving all of the quadtree blocks in the underlying spatial database that cover the quadtree blocks that comprise the window. It works by decomposing the window operation into sub-operations over smaller window partitions. These partitions are the quadtree blocks corresponding to the window. Although a block b in the underlying spatial database may cover several of the smaller window partitions, b is only retrieved once rather than multiple times. This is achieved by using an auxiliary main memory data structure called the active border which requires O(n) additional storage for a window query of size n×n. As a result, the algorithm generates an optimal number of disk I/O requests to answer a window query (i.e., one request per covering quadtree block). A proof of correctness and an analysis of the algorithm's execution time and space requirements are given, as are some experimental results.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1009760201355
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  • 10
    Digitale Medien
    Digitale Medien
    Decomposing a window into maximal quadtree blocks (1993)
    Springer
    Acta informatica 30 (1993), S. 425-439 
    Details
    ISSN: 1432-0525
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik
    Notizen: Abstract Window operations serve as the basis of a number of queries that can be posed in a spatial database. Examples of window-based queries include the exist query (i.e., determining whether or not a spatial feature exists inside a window), the report query (i.e., report the identity of all the features that exist inside a window), and the select query (i.e., determine the locations covered by a given feature inside a window). Often spatial databases make use of a quadtree decomposition, which yields a set of maximal blocks, to enable the features to be accessed quickly without having to search the entire database. One way to perform a window query is to decompose the window into its maximal quadtree blocks. An algorithm is described for decomposing a two-dimensional window into its maximal quadtree blocks inO(nlog logT) time for a window of sizen×n in a feature space (e.g., an image) of sizeT×T (e.g., pixel elements).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01210594
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