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.
HyperReal is an object-based programming paradigm which introduces a time-driven control model as a primitive mechanism. A system consists of a collection of actors which are not aware of timing issues. Timing is spec...
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HyperReal is an object-based programming paradigm which introduces a time-driven control model as a primitive mechanism. A system consists of a collection of actors which are not aware of timing issues. Timing is specified at a programming-in-the-large level, thus improving modularity and re-usability. The paper discusses the rationale for this approach;introduces HR2, an Oberon-based subset of HyperReal;and presents a set of examples which highlight how HR2 can be used for supporting different control disciplines.
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.
This paper will describe one approach to the design and implementation of a multibody systems analysis code using an object-oriented architecture. The principal objective is to show the adequacy between object-oriente...
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This paper will describe one approach to the design and implementation of a multibody systems analysis code using an object-oriented architecture. The principal objective is to show the adequacy between object-oriented programming and the finite element method used for the treatment of three-dimensional multibody flexible mechanisms. It will show that object-oriented programming greatly simplifies the choice and the implementation of other formalisms concerning polyarticulated systems, thus conferring high flexibility and adaptability to the developed software. (C) 2004 Elsevier Ltd. All rights reserved.
Class constructors play an indispensable role in the Java language as a mechanism for object creation. However, little empirical evidence exists on constructors, trends in their composition and how a class with too ma...
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Class constructors play an indispensable role in the Java language as a mechanism for object creation. However, little empirical evidence exists on constructors, trends in their composition and how a class with too many constructors might influence its understandability by developers. Herein, the authors investigate the applicability of the 'replace constructors with creation methods' (RCwCM) refactoring of Kerievsky in five Java systems. The RCwCM was manually applied to a set of classes from each of the five systems in classes containing three or more constructors. The benefits of this refactoring include improved code readability and encapsulation, program understanding and to a lesser extent possible elimination of code duplication. Within each of the five systems, evidence of scope for applying the RCwCM refactoring based on the number of classes with multiple constructors was found. However, problems were encountered that limited its application. These are the nature of inheritance and the different styles of accessing class constructors. In the former, account has to be taken of multiple dependencies if the class is not a leaf class;in the latter, the 'super' construct requires careful handling. When considered against the benefits that the RCwCM provides, care needs to be exercised. As with any refactoring effort, the short and long-term benefits need to be compared with the expense outlay (developer time and effort) as well as the opportunity cost.
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.
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