Automatic evaluation of drawing-to-CAD conversion performance is addressed. The generating model of artificial images in the domain of cadastral maps was built. The proposed model was close to the authentic drawings o...
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Automatic evaluation of drawing-to-CAD conversion performance is addressed. The generating model of artificial images in the domain of cadastral maps was built. The proposed model was close to the authentic drawings on the level of graphic primitives and on the level of map understanding. The shape of the parcel was characterized by the number of corners, line lengths and respective angles. The model of a house consists of 12 random variables, while the 13th variable describes the location of the house in a parcel. The parameters of probability distributions have been estimated from the sample of 115 parcels and 127 houses. The goodness-of-fit for all distributions was very high.< >
A major limitation of the boundary element method (BEM) for the solution of electrical potential problems is the long computational time required. However, a large portion of the calculations involved can be viewed as...
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A major limitation of the boundary element method (BEM) for the solution of electrical potential problems is the long computational time required. However, a large portion of the calculations involved can be viewed as being parallel in nature and can therefore be computed concurrently. This paper makes an effort to increase the efficiency of the BEM process using transputer-based multiprocessor computing techniques. The algorithms developed may equally well be applied to any multiprocessor system. The application selected to demonstrate the technique is the solution of an electrostatic problem governed by a two-dimensional Laplace equation. A parallel algorithm for problem setup and field extraction using BEM is designed and implemented on a transputer array. Special attention is directed to the utilization of the parallel processors to achieve maximum efficiency. The analysis in this work concentrates on the communication strategies for passing data between processors as well as a consideration of the workload attributed to each processor. The parallel algorithms were implemented using 3L Parallel Fortran;however, the choice of topology for the overall BEM implementation was limited by the fact that certain parts of the algorithm could only utilize a pipeline configuration of processors. Comprehensive results for the parallel BEM algorithm are given and they are encouraging, indicating that parallel processing has much to offer when applied to the boundary element method.
A major limitation of the transmission-line matrix (TLM) method used to solve Maxwell's equations is the long computation time required. The TLM scattering calculations involved can, however, be viewed as parallel...
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A major limitation of the transmission-line matrix (TLM) method used to solve Maxwell's equations is the long computation time required. The TLM scattering calculations involved can, however, be viewed as parallel in nature. This paper describes an effort to reduce computational time by using an SIMD, DAP multiprocessor computer employed to solve a two-dimensional TLM electromagnetic field formulation. A parallel algorithm based on the TLM scattering algorithm is designed and implemented using FORTRAN-PLUS Enhanced on an AMT DAP 510 machine. Here the connectivity of the DAP is exploited to simulate the intrinsic scattering behaviour on which the TLM algorithm relies. The results show that parallel processing on an SIMD machine such as the DAP is advantageous, especially for higher-order mesh sizes.
There have been active work to extend the Prolog style Horn Clause logic programming to non-Horn *** this paper,we will analyze the complexities of several such *** purpose is to understand the computational complexit...
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There have been active work to extend the Prolog style Horn Clause logic programming to non-Horn *** this paper,we will analyze the complexities of several such *** purpose is to understand the computational complexity of these inference *** analyses do not prove that any one system is better than the others all the *** they do suggest that one system may be better than the others for some particular *** also discuss the effect of caching.
Lazy functional languages have non-strict semantics and are purely declarative, i.e. they support the notion of referential transparency and are devoid of side effects. Traditional debugging techniques are, however, n...
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The unification problem for terms containing associative and commutative functions is of importance in theorem provers based on term rewriting and resolution methods as well as in logic programming. The complexity of ...
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This paper proposes a new system for feature- based modelling- ISFBM with built in strategy for defining details by their features, realizing design process over the computational model of rule- based systems paradigm...
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In this paper we present the ObjectMath language, a hybrid language integrating object-oriented constructs with features for symbolic and numeric computation. Complex mathematical models may be implemented in a natura...
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作者:
Jones, Mark P.Programming Research Group
Oxford University UK Department of Computer Science Yale University Yale Station New Haven CT 06520-2158 PO Box 2158 United Kingdom
This paper presents a simple framework for performing calculations with the elements of (finite) lattices. A particular feature of this work is the use of type classes to enable the use of overloaded function symbols ...
An algorithm for computing a complete set of unifiers for two terms involving associative-commutative function symbols is presented. It is based on a nondeterministic algorithm given by the authors in 1986 to show the...
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An algorithm for computing a complete set of unifiers for two terms involving associative-commutative function symbols is presented. It is based on a nondeterministic algorithm given by the authors in 1986 to show the NP-completeness of associative-commutative unifiability. The algorithm is easy to understand, and its termination can be easily established. Its complexity is easily analyzed and shown to be doubly exponential in the size of the input terms. The analysis also shows that there is a double-exponential upper bound on the size of a complete set of unifiers of two input terms. Since there is a family of simple associative-commutative unification problems which have complete sets of unifiers whose size is doubly exponential, the algorithm is optimal in its order of complexity in this sense.< >
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