This paper presents an algebraic specification of net objects. By net objects we mean those that are defined in object-oriented paradigms and those defined with nested relations in complex database models. An algebrai...
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This paper presents an algebraic specification of net objects. By net objects we mean those that are defined in object-oriented paradigms and those defined with nested relations in complex database models. An algebraic specification is set up that involves structures of net objects, accesses of net objects, and some features of object-oriented programming, such as multiple inheritance and polymorphism. objects and their relationships are then characterized formally in the modeling, which utilizes the hierarchical approach in the algebraic theory of abstract data types, and is further developed by adding mechanisms from existing object systems. Categories of net objects are presented with the properties of accesses among them.
This paper reports a scalar implementation of a multi-dimensional direct simulation Monte Carlo (DSMC) package named "Generalized Rarefied gAs Simulation Package" (GRASP). This implementation adopts a concep...
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This paper reports a scalar implementation of a multi-dimensional direct simulation Monte Carlo (DSMC) package named "Generalized Rarefied gAs Simulation Package" (GRASP). This implementation adopts a concept of simulation engine and it utilizes many object-oriented programming features and software engineering design patterns. As a result, this implementation successfully resolves the problem of program functionality and interface conflictions for multi-dimensional DSMC implementations. The package has an open architecture which benefits further development and code maintenance. To reduce engineering time for three-dimensional simulations, one effective implementation is to adopt a hybrid grid scheme with a flexible data structure, which can automatically treat cubic cells adjacent to object surfaces. This package can utilize traditional structured, unstructured or hybrid grids to model multi-dimensional complex geometries and simulate rarefied non-equilibrium gas flows. Benchmark test cases indicate that this implementation has satisfactory accuracy for complex rarefied gas flow simulations. Published by Elsevier Ltd.
C++ [1, 2] extends a modern, general purpose programming language into the object-oriented programming paradigm. The language ameliorates disadvatanges of C while introducing new problems. Advantages and disadvantages...
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C++ [1, 2] extends a modern, general purpose programming language into the object-oriented programming paradigm. The language ameliorates disadvatanges of C while introducing new problems. Advantages and disadvantages of traditional C [3, 4] have been discussed in [5]. This paper assesses C++, examining why it is better general purpose programming langauge. Since C++ is “object-oriented” we consider how well it implements that metaphor. In this paper we assume the reader has a working knowledge of the C programming language. Section 1 briefly enumerates advantages and disadvantages of C to provide a context for assessing C++. In Section 2 we describe new C++ features and discuss ways they ameliorate shortcomings of C. Section 3 describes philosophical and practical problems with C++. The last section assesses C++ as a successor to C.
In this paper, we present a symbolic approach to automating the elaboration of numerical tools for the simulation of physical processes using the finite element method. We aim at developing a generic environment to au...
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In this paper, we present a symbolic approach to automating the elaboration of numerical tools for the simulation of physical processes using the finite element method. We aim at developing a generic environment to automate discretization schemes in the context of PDEs. The approach is implemented in a consistent object-oriented tool built in Java. We propose a symbolic environment to automatically build the symbolic forms of elemental contributions corresponding to a variational formulation. These contributions are automatically introduced into a classical simulation tool. The basic object-oriented framework covering the elaboration of the elemental contributions derived from the weak statement is briefly discussed. The approach can be naturally extended to any discretization model in space or time. This approach is illustrated by the example of hyperelasticity. (C) 2016 Elsevier Ltd. All rights reserved.
A general-purpose object-oriented fatigue tool set has been designed and implemented that can serve not only as a stand-alone code for preliminary design studies, but also as a foundation for highly complex industrial...
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A general-purpose object-oriented fatigue tool set has been designed and implemented that can serve not only as a stand-alone code for preliminary design studies, but also as a foundation for highly complex industrial 'in-house' fatigue codes. Due to their programming structure, these tools may easily be modified to include additional fatigue prediction methods. Three component libraries have been created to address three topics in fatigue analysis: (1) fatigue material property definition;(2) basic fatigue calculations;and (3) cumulative damage calculations. The initial programming framework has been supplemented, demonstrating the expandability of the libraries. The component libraries have been incorporated into three programs to verify their capabilities and demonstrate their use.
An object-oriented finite element/finite volume software, EasyFEM, has been developed. The software, with a fully interactive graphics interface, analyses heat transfer, solid mechanics, and fluids problems by the fin...
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An object-oriented finite element/finite volume software, EasyFEM, has been developed. The software, with a fully interactive graphics interface, analyses heat transfer, solid mechanics, and fluids problems by the finite element and the finite volume methods. The Coad and Yourdon methodology is used to describe the general structure of classes and objects implemented by the software. Details of the object-oriented classes for both the graphics pre- and post-processors, as well as for the analysis solutions, are described. Several case studies with graphical representations of numerical solutions are presented to illustrate some functionalities of the software. (C) 2006 Elsevier Ltd. All rights reserved.
Late binding and subtyping create run-time overhead for object-oriented languages, especially in the context of both multiple inheritance and dynamic loading, for instance for JAVA interfaces. In a previous article, w...
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Late binding and subtyping create run-time overhead for object-oriented languages, especially in the context of both multiple inheritance and dynamic loading, for instance for JAVA interfaces. In a previous article, we proposed a novel approach based on perfect hashing and truly constant-time hashtables for implementing subtype testing and method invocation in a dynamic loading setting. In this first study, we based our efficiency assessment on Driesen's abstract computational model for the time aspect, and on large-scale benchmarks for the space aspect. The conclusions were that the technique was promising but required further research in order to assess its scalability. This article presents some new results on perfect class hashing that enhance its interest. We propose and test both new hashing functions and an inverse problem that amounts to selecting the best class identifiers in order to minimize the overall hashtable size. This optimizing approach is proven to be optimal for single-inheritance hierarchies. Experiments within an extended testbed with random class loading and under cautious assumptions about what should be a sensible class-loading order show that perfect class hashing scales up gracefully, especially on JAVA-like multiple-subtyping hierarchies. Furthermore, perfect class hashing is implemented in the PRM compiler testbed, and compared here with the coloring technique, which amounts to maintaining the single-inheritance implementation in multiple inheritance. The overall conclusion is that the approach is efficient from both time and space standpoints with the bit-wise and hashing function. In contrast, the poor time efficiency of modulus hashing function on most processors is confirmed. Copyright (C) 2010 John Wiley & Sons, Ltd.
This research paper presents a prototype object-oriented and rule-based system for product cost modelling and design for automation at an early design stage. The developed system comprises a computer aided design (CAD...
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This research paper presents a prototype object-oriented and rule-based system for product cost modelling and design for automation at an early design stage. The developed system comprises a computer aided design (CAD) solid modelling system, a material selection module, a knowledge-based system (KBS), a process optimization module, a design for assembly module, a cost estimation module and a user interface. The system development process has passed through four major steps: constructing the knowledge-based and process optimization system;developing a design for assembly module;integrating the KBS with both a material selection database and the CAD system;developing and implementing a fuzzy logic approach to generate reliable estimation of cost and to handle the uncertainty in the cost estimation model that cannot be addressed by traditional analytical methods. Two manufacturing processes, namely machining and injection moulding processes, were considered in the developed system. The main function of the system, besides estimating the product cost, is to generate initial process planning, including the generation and selection of machining processes, their sequence and their machining parameters, and to recommend the most economical assembly technique for a product and provide design improvement suggestions based on a design feasibility technique. In addition, a feature-by-feature cost estimation report is generated using the proposed system to highlight the features of high manufacturing cost. Two case studies were used to validate the developed system.
The Trust4All project aims to define an open, component-based framework for the middleware layer in high-volume embedded appliances that enables robust and reliable operation, upgrading and extension. To improve the a...
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The Trust4All project aims to define an open, component-based framework for the middleware layer in high-volume embedded appliances that enables robust and reliable operation, upgrading and extension. To improve the availability of each individual application in a Trust4All system, a runtime configurable fault management mechanism (FMM) is proposed, which detects deviations from given service specifications by intercepting interface calls. When repair is necessary, FMM picks a repair action that incurs the best tradeoff between the success rate and the cost of repair. Considering that it is rather difficult to obtain sufficient information about third party components during their early stage of usage, FMM is designed to be able to accumulate knowledge and adapts its capability accordingly.
Cloud computing has paved the way for advance of IT-based on demand services. This technology helps decrease capital expenditure and operation costs, solve scalability issue and many more user and provider constraints...
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Cloud computing has paved the way for advance of IT-based on demand services. This technology helps decrease capital expenditure and operation costs, solve scalability issue and many more user and provider constraints. However, development and deployment of distributed applications on cloud environment becomes a more and more complex task. Cloud users must spend a lot of time to prepare, install and configure their applications on clouds. In addition, after development and deployment, the applications almost cannot move from one cloud to another due to the lack of interoperability between them. To address these problems, in this paper we present a novel development and deployment framework for cloud distributed applications/services. Our approach is based on abstraction and object-oriented programming technique, allowing users to easily and rapidly develop and deploy their services into cloud environment. The approach also enables service migration and interoperability among the clouds.
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