Cohn A. (1995), The Challenge of Qualitative Spatial Reasoning, Division of Artificial Intelligence, School of Computer Studies, University of Leeds, England.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....to find out a solution path in terms of time and memory. Particularly, in the qualitative spatial reasoning area, where the authors have done the study of topological interactions among and their causes and effects, it raises very complex problems in terms of branching and solution depth[2]. We have developed the N Best algorithm (see figure 1) aiming at finding out a solution path without a complete successor generation in order to cope with high branching factors and solution depths which are always found in this kind of problems. 1. Add(Open, si, Fo) 2. If Open=cI) then ....

Cohn A. (1995), The Challenge of Qualitative Spatial Reasoning, Division of Artificial Intelligence, School of Computer Studies, University of Leeds, England.

....are used in many inferences in forest management are spatial concepts such as measuring point, continuance, district and more. These objects, relations between them and inferences that may be concluded between them are a kind of commonsense knowledge. There are theories in artificial intelligence (Cohn 1995), Kautz 1995) that support these inferences however they are computationally very expensive and it must be investigated further whether explicit inferences are sufficient for the domain. In the scientific theory of the whole domain one typical inference structure are determination keys. These ....

Cohn, A.G. (1995) The Challenge of Qualitative Spatial Reasoning, Computing Surveys 27 (3) pp. 323-327.

....always has exponential complexity, mainly because real world problems produce models with high branching factors and solution depths. Therefore, the study and implementation of control strategies and cooperation among them are essential to meet the challenge of search complexity reduction [1]. In particular, improvements on two fundamental steps of the process successor generation and state completion can reduce drastically the search effort. In this paper, some search strategies are introduced, such as the utilization factor and the use of several lists of open nodes. Some ....

Cohn A. (1995), The Challenge of Qualitative Spatial Reasoning, Division of Artificial Intelligence, School of Computer Studies, University of Leeds, England.

....A.I. problems since that they can be represented in terms of states and operators. However, when we try to modeling and solving certain real world problems, where the number of operators grows up exponentially with the number of elements in the domain (e.g. qualitative spatial reasoning area [4]) special search approaches are needed to find out practical solutions. As though, this kind of problems and mainly their search space dimension raise practical difficulties, which are incomparable bigger than the NP complete problems that usually appear in A.I. bibliography (e.g. chess problem) ....

....whether the center tile is not correct) to measuring the distance from the current state to the final state. The Rotating sequence function makes this heuristic function not admissible but it is much more informative. The search algorithms used in this performance analysis are the RTA [3] the WA [4], the N Best algorithm (with N=1) and the Pruned N Best algorithm (see figure 1) with different values of N. The WA algorithm uses a weighted version of ( s f , namely ( s h W s g W 1 s f = for 1 W 0 , and in this test the value of W is fixed at 0,5. All search algorithms ....

Cohn A. (1995), The Challenge of Qualitative Spatial Reasoning, Division of Artificial Intelligence, School of Computer Studies, University of Leeds, England.

....features of common sense reasoning. Defaults are values or propositions that are supposed to be true unless there is information that says otherwise. 2.1. 2 QUALITATIVE REASONING Instead of doing exact calculations, people most often apply qualitative methods of spatial reasoning (Frank 1996, Cohn 1995, Frank 1992, Freksa 1992) that rely on magnitudes and relative, instead of absolute, values. When people perceive space through different channels they arrive at various kinds of information that are usually qualitative in nature. People rarely move through the environment using rulers or tape ....

A. Cohn (1995) The Challenge of Qualitative Spatial Reasoning. ACM Computing Surveys 27(3): 323-325.

....standard concepts of space are not always appropriate (Frank 1992) People s reasoning is mainly based on common sense and they often do not think mathematically in everyday affairs. Instead of doing exact calculations, people most often apply methods of qualitative spatial reasoning (Frank 1996, Cohn 1995, Frank 1992, Freksa 1992) which rely on magnitudes and relative, instead of absolute, values. People also usually use topological instead of metrical information. Topological properties of objects stay invariant under such transformations as translations, rotations, and scalings. By using ....

A. Cohn (1995) The Challenge of Qualitative Spatial Reasoning. ACM Computing Surveys 27(3): 323-325.

.... qualitative arithmetic algebras have been devised (Weld and de Kleer 1990; Williams and de Kleer 1991) Qualitative reasoning has been applied mainly to scalar quantities and only recently to space, which is multidimensional in nature, giving rise to the subfield of qualitative spatial reasoning (Cohn 1995, 1996; Hern andez 1994) The delay in the development of qualitative models and reasoning techniques for spatial domains is partly due to the convincement that it seems unlikely that such inference schemes will be useful for tasks that require full higher dimensional manipulations (Forbus, ....

Cohn, A. G. (1995). The challenge of qualitative spatial reasoning. Computing Surveys, 27 (3), 323--327.

.... (e.g. south, northwest) 13] topological relations that describe concepts of neighbourhood and incidence (e.g. overlap, disjoint) 8] and distances (e.g. near, far) 17] The above types of relations have been used in a wide range of topics, such as Spatial Query Languages [12, 26] Reasoning [5, 17] and Consistency Checking Mechanisms [9, 14] This paper describes implementations of direction relations in Spatial Database Management Systems (SDBMS) and Geographical Information Systems (GIS) Despite the fact that directions constitute an important class of user queries, they have not been ....

A.G. Cohn, The Challenge of Qualitative Spatial Reasoning, ACM Computing Surveys, 27 (1995) 323-325.

....can be used for representing and reasoning about the motion of rigid bodies within a confining environment. 1 Introduction Many researchers in the field of Qualitative Spatial Reasoning (QSR) have argued that it is useful to have representations in which spatial regions are the basic entities (Cohn 1995, Davis 1988, Cohn 1997) This ontology contrasts with the approach of classical geometry, where lines, surfaces and regions are typically thought of as sets of points. To meet this need several region based theories have been proposed (Randell, Cui and Cohn 1992, Asher and Vieu 1995) 1 However, ....

Cohn, A. G.: 1995, The challenge of qualitative spatial reasoning, Computing Surveys.

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Cohn, A., "The Challenge of Qualitative Spatial Reasoning". ACM Computing Surveys, vol. 27, pp. 323-325, 1995.

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