A finite element method, with the adaptive Delaunay triangulation as mesh generator, is used to analyze two-dimensional crack propagation problems. This paper describes the Delaunay triangulation procedure consisting ...
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A finite element method, with the adaptive Delaunay triangulation as mesh generator, is used to analyze two-dimensional crack propagation problems. This paper describes the Delaunay triangulation procedure consisting of mesh generation, node creation, mesh smoothing, and adaptive remeshing, all with object-oriented programming. The adaptive remeshing technique generates small elements around crack tips and large elements in other regions. The resulting stress intensity factors and simulated crack propagation behavior are used to evaluate the effectiveness of the combined method. The accuracy of the stress intensity factor prediction is evaluated in three test cases, a center cracked plate, a single edge cracked plate and a compact tension specimen. Then, crack growth trajectories in a single edge cracked plate with three holes and a single edge cracked plate under mixed-mode loading are simulated and results assessed. (C) 2004 Elsevier B.V. All rights reserved.
Incremental changes add new functionality and new properties to software. They are the basis of software maintenance, evolution, incremental development, agile development, and other important software engineering pro...
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Incremental changes add new functionality and new properties to software. They are the basis of software maintenance, evolution, incremental development, agile development, and other important software engineering processes. This article presents selected incremental change activities-change request, concept extraction, concept location, impact analysis, actualization, incorporation, change propagation, refactoring, and role splitting-in which programming concepts and program dependencies play a key role. The authors provide an example that illustrates an incremental change in the open source software Drawlets.
This work presents an object-oriented numerical framework for the development of computer programs based on the boundary element method (BEM). The proposed design provides a large set of classes developed specially to...
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This work presents an object-oriented numerical framework for the development of computer programs based on the boundary element method (BEM). The proposed design provides a large set of classes developed specially to handle those entities most commonly found in BEM solution procedures. The framework is divided into three basic sets of classes that enable the analyst to build the code accordingly to the type of problem to be solved. The design also allows the use of an arbitrary number of subregions, which are connected automatically by imposing compatibility conditions on the interfaces. Code fragments illustrate how the use of the proposed framework can simplify the development cycle of research software based on the BEM. (C) 2004 Elsevier Ltd. All rights reserved.
The embedding of a small but expressive language of multidimensional functional programming in a well known and widely used language of object-oriented programming leads to the combination of two radically different p...
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The embedding of a small but expressive language of multidimensional functional programming in a well known and widely used language of object-oriented programming leads to the combination of two radically different programming models. In this paper, we formally define the syntax and semantics of GLU, which can be thought of as the multidimensional core of Lucid and GLU, and we describe its implementation as a language embedded in C++. With the aid of a few examples, we argue that the marriage of the two programming models is not only compatible and natural, but also that it produces a new and interesting hybrid language. Copyright (C) 2004 John Wiley Sons, Ltd.
This paper presents a framework which implements the common software functionalities. By using this framework, software designers focus on their activity on developing efficient data structures and algorithms. The log...
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This paper presents a framework which implements the common software functionalities. By using this framework, software designers focus on their activity on developing efficient data structures and algorithms. The logic programming introduced in this framework is an efficient technology for object Constraint Language expressions. Errors made by the user when modeling a device are detected and prevented by the modeling guide.
A new system of library code is proposed and initiated. It is emphasized that the same terminologies as we find in our textbooks should be used for class names in the library code. This proposal is inspired by .NET of...
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A new system of library code is proposed and initiated. It is emphasized that the same terminologies as we find in our textbooks should be used for class names in the library code. This proposal is inspired by .NET of Microsoft. Several rules of thumb are suggested in order to obtain easy-readable coherent codes. As a first step, we present the library code for exact diagonalization in physics. When we build codes, we distinguish between model independent and dependent parts. For the model independent parts, we use the familiar terminologies like Hamiltonian, HilbertSpace, GroundState, etc as class names. As an explicit example, we calculate ground state energy of a quantum dot, showing the triplet-singlet transition.
Este trabalho tem por objetivo contribuir para o desenvolvimento de técnicas de Educação em Engenharia apresentando uma ferramenta de apoio ao Ensino/Aprendizagem de Sistemas Elétricos de Potê...
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Este trabalho tem por objetivo contribuir para o desenvolvimento de técnicas de Educação em Engenharia apresentando uma ferramenta de apoio ao Ensino/Aprendizagem de Sistemas Elétricos de Potência na forma de um software de interface amigável e baixo custo. O software desenvolvido em linguagem C++ segue os padrões de programação orientada a objetos e oferece ao usuário a resolução de fluxos de potência e simulações de casos de contingências transitórias com possibilidade de interatividade, apresentando resultados em ambiente gráfico. Desenvolvido para aplicação na área de Dinâmica e Estabilidade de Sistemas de Potência, suporta sistemas-exemplos clássicos do IEEE e também disponibiliza ao usuário ferramentas para personalização de arquivos de dados de entrada, tornando-se flexível e de fácil acesso aos casos já inseridos no sistema. O usuário também pode criar novos sistemas de acordo com suas necessidades. Os resultados são exibidos em forma numérica e também através de gráficos tridimensionais e animação, possibilitando fácil visualização de resultados, entendimento de fenômenos e análise de influências sobre o *** work presents a contribution to the development of Engineering Education techniques by means of a Teaching/Learning support tool for Electrical Power System studies resulting in a friendly low cost interface software. It was developed in C++ language and follows the pattern of objectorientedprogramming, offering to the user the resolution of load flow and digital simulations of transient stability with the possibility of interactivity, showing the results in a graphic environment. It was developed for use in applications of Static and Transient Power Systems Stability and it has enclosed classic sample-systems of IEEE and others and also allows the user to customize input data files. Then the tool is flexible and enables easy access to cases formerly inserted in the system. The user also can create new systems according to his needs. The m
A CAD system for Multi and Tall Steel Frame based on objectArx and the features of Engineering Project Design is developed on AutoCAD API with the objectoriented technique. The method of developing Multi and Tall Ste...
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A CAD system for Multi and Tall Steel Frame based on objectArx and the features of Engineering Project Design is developed on AutoCAD API with the objectoriented technique. The method of developing Multi and Tall Steel Frame CAD system based on objectArx is presented in detail in this paper. Some key elements such as the main framework of CAD system, interface control technology, the analysis of model objects and achieving of class, the graphic display of definition entity, the separation of data and user interface are included. The practicability of these technologies is verified.
One key to several quality factors of software is the way components are connected. Software coupling can be used to estimate a number of quality factors, including maintainability, complexity, and reliability. object...
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One key to several quality factors of software is the way components are connected. Software coupling can be used to estimate a number of quality factors, including maintainability, complexity, and reliability. object-oriented languages are designed to reduce the number of dependencies among classes, which encourages separation of concerns and should reduce the amount of coupling. At the same time, the object-oriented language features change the way the connections are made, how they must be analyzed, and how they are measured. This paper discusses software couplings based on object-oriented relationships between classes, specifically focusing on types of couplings that are not available until after the implementation is completed, and presents a static analysis tool that measures couplings among classes in Java packages. Data from evaluating the tool on several open-source projects are provided. The coupling measurement is based on source code, which has the advantage of being quantitative and more precise than previous measures, but the disadvantage of not being available before implementation, and thus not useful for some predictive efforts.
Multiphysics applications are real world problems with a large number of different shape components that obey different physical laws and manufacturing constraints and interact with each other through geometric and ph...
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Multiphysics applications are real world problems with a large number of different shape components that obey different physical laws and manufacturing constraints and interact with each other through geometric and physical interfaces. They demand accurate and efficient solutions and a modern type of computational modeling, which designs the whole physical system with as much detail as possible. The simulation of gas turbine engine is such a multiphysics application and is realized with GasTurbnLab, an agent-based Multiphysics Problem Solving Environment (MPSE). Its performance and evaluation study is presented in this paper. For this, a short description of the software components and hardware infrastructure is given. The performance and the scalability of the parallelism are depicted, and the communication overhead between agents is studied with respect to the number of agents and their location in the "computational grid." The execution time is recorded, and its analysis verifies the complexity of the solvers in use and the performance of the available hardware. Three different clusters of INTEL Pentium processors were used for experimentation to study how the communication time was affected by processor's homogeneity/heterogeneity and the different connections between the processors. The study of the numerical experiments shows that the domain decomposition and interface relaxation methodology, along with the usage of agent platforms, does not increase the complexity of the simulation problem, and the communication cost is too low, compared with the computations, to reflect on the total simulation time. Therefore, GasTurbnLab is an efficient example of a complex physical phenomena simulation.
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