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CWA Formalizations in Multi-Valued Logics

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Journal of Computer Science & Technology 2001年第3期16卷 263-269页

作者：吴尽昭 Max-Planck-Institut für informatik Saarbrücken Germany

To enhance the expressive power and the declarative ability of a deductive database, various CWA (Closed World Assumption) formalizations including the naive CWA, the generalized CWA and the careful CWA are extended to multi-valued logics. The basic idea is to embed logic formulas into some polynomial ring. The extensions can be applied in a uniform manner to any finitely multi-valued logics. Therefore they are also of computational significance.

关键词： CWA formalization multi-valued logic polynomial form query evaluation

An Open Platform for Processing IFC Model Versions

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Tsinghua Science and Technology 2008年第S1期13卷 126-131页

作者： Mohamed Nour Karl Beucke informatik im Bauwesen Bauhaus-University Weimar

The IFC initiative from the International Alliance of Interoperability has been developing since the mid-nineties through several versions. This paper addresses the problem of binding the growing number of IFC versions and their EXPRESS definitions to programming environments (Java and .NET). The solution developed in this paper automates the process of generating early binding classes, whenever a new version of the IFC model is released. Furthermore, a runtime instantiation of the generated early binding classes takes place by importing IFC-STEP ISO 10303-P21 models. The user can navigate the IFC STEP model with relevance to the defining EXPRESS-schema, modify, delete, and create new instances. These functionalities are considered to be a basis for any IFC based implementation. It enables researchers to experiment the IFC model independently from any software application.

关键词： IFC EXPRESS STEP, bindings .NET Java

ON ADAPTIVE WAVELET BOUNDARY ELEMENT METHODS

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Journal of Computational Mathematics 2018年第1期36卷 90-109页

作者： H. Harbrecht M. Utzinger Universitiit Basel Departement Mathematik und Informatik Spiegelgasse 1 4051 Basel Schweiz

The present article is concerned with the numerical solution of boundary integral e- quations by an adaptive wavelet boundary element method. This method approximates the solution with a computational complexity that is proportional to the solution＇s best N-term approximation. The focus of this article is on algorithmic issues which includes the crucial building blocks and details about the efficient implementation. By numerical examples for the Laplace equation and the Helmholtz equation, solved for different geome- tries and right-hand sides, we validate the feasibility and efficiency of the adaptive wavelet boundary element method.

关键词： Boundary element method Wavelets Adaptivity.

Modified Lagrangian and Least Root Approaches for General Nonlinear Optimization Problems

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维普期刊数据库

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Acta Mathematicae Applicatae Sinica 2002年第1期18卷 147-152页

作者： W.Oettli Fakultat fur Mathematik und informatik Universitat Mannheim68131 MannheimGermany

In this paper we study nonlinear Lagrangian methods for optimization problems with side constraints. Nonlinear Lagrangian dual problems are introduced and their relations with the original problem are established. Mor... 详细信息

关键词： Generalized Lagrangian Zero duality gap least root approach

Surfel-based surface modeling for robotic belt grinding simulation

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第7期7卷 1215-1224页

作者： REN Xiang-yang MUELLER Heinrich KUHLENKOETTER Bernd Robotics Research Institute University of Dortmund Dortmund 44227 Germany informatik VII University of Dortmund Dortmund 44227 Germany

The new flee-form surface modelling technology for robotic belt grinding simulation presented in this paper is based on discrete surfel elements generated from the surface approximation point set and can facilitate the simulation implementation. A local process model exploits the advantage of surfel representation to compute the material removal rate and the final surface grinding error can be easily carried out. With the help of this system, robot programmers can improve the path planning and predict potential problems by visualizing the manufacturing process.

关键词： Surface modelling Surfel Belt-grinding simulation

A Prototype Expert System for Automatic Generation of Image Processing Programs

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Journal of Computer Science & Technology 1991年第3期6卷 296-300页

作者：宋茂强 FelixGrimm HorstBunke Beijing University of Posts and Telecommunications Beijing 100088 Institut fuer informatik Universitaet BernSwitzerland

A prototype expert system for generating image processing programs using the subroutine pack- age SPIDER is described in this *** on an interactive dialog,the system can generate a complete application program using S... 详细信息

关键词： A Prototype Expert System for Automatic Generation of Image Processing Programs

The Dichotomy Between Traces on d-sets Г in R^n and the Density of D(R^n\Г) in Function Spaces

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Acta Mathematica Sinica,English Series 2008年第4期24卷 539-554页

作者： Hans TRIEBEL Mathematisches Institut Fakultt fr Mathematik und InformatikFriedrich-Schiller-Universitt JenaD-07737 JenaGermany

A space Apq^s （R^n） with A ： B or A = F and s ∈R, 0 〈 p, q 〈 ∞ either has a trace in Lp（Г）, where Г is a compact d-set in R^n with 0 〈 d 〈 n, or D（R^n／Г） is dense in it. Related dichotomy numbers are ... 详细信息

A space Apq^s （R^n） with A ： B or A = F and s ∈R, 0 〈 p, q 〈 ∞ either has a trace in Lp（Г）, where Г is a compact d-set in R^n with 0 〈 d 〈 n, or D（R^n／Г） is dense in it. Related dichotomy numbers are introduced and calculated.

关键词： function spaces d-sets fractals traces

Approximation Algorithms for 3D Orthogonal Knapsack

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Journal of Computer Science & Technology 2008年第5期23卷 749-762页

作者： Florian Diedrich Rolf Harren Klaus Jansen Ralf Thle Henning Thomas Institute of Computer Science University of Kiel Max-Planck-Institut für informatik Campus E1466123 Saarbrücken Germany Department of Computer Science ETH ZurichZurich Switzerland

We study non-overlapping axis-parallel packings of 3D boxes with profits into a dedicated bigger box where rotation is either forbidden or permitted, and we wish to maximize the total profit. Since this optimization problem is NP-hard, we focus on approximation algorithms. We obtain fast and simple algorithms for the non-rotational scenario with approximation ratios 9 ＋ ε and 8 ＋ ε, as well as an algorithm with approximation ratio 7 ＋ ε that uses more sophisticated techniques; these are the smallest approximation ratios known for this problem. Furthermore, we show how the used techniques can be adapted to the case where rotation by 90° either around the z-axis or around all axes is permitted, where we obtain algorithms with approximation ratios 6 ＋ ε and 5 ＋ ε, respectively. Finally our methods yield a 3D generalization of a packability criterion and a strip packing algorithm with absolute approximation ratio 29/4, improving the previously best known result of 45/4.

关键词： approximation algorithm computational and structural complexity geometric configurations

Supporting Consistency in Linked Specialized Engineering Models Through Bindings and Updating

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Tsinghua Science and Technology 2008年第S1期13卷 165-170页

作者： Albertus H. Olivier Gert C. van Rooyen Berthold Firmenich Karl E. Beucke CAD in der Bauinformatik Department of Civil Engineering Bauhaus-University Weimar Civil Engineering Informatics Department of Civil Engineering University of Stellenbosch informatik im Bauwesen Department of Civil Engineering Bauhaus-University Weimar

Currently, some commercial software applications support users to work in an integrated environment. However, this is limited to the suite of models provided by the software vendor and consequently it forces all the parties to use the same software. In contrast, the research described in this paper investigates ways of using standard software applications, which may be specialized for different professional domains. These are linked for effective transfer of information and a binding mechanism is provided to support consistency. The proposed solution was implemented using a CAD application and an independent finite element application in order to verify the theoretical aspects of this work.

关键词： CAD/FEM integration structural engineering model consistency support binding mechanism