The authors' technique for process definition demonstrates practical value beyond direct project planning and risk mitigation: using object-oriented technology metaphors, it can express responsibilities and collab...
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The authors' technique for process definition demonstrates practical value beyond direct project planning and risk mitigation: using object-oriented technology metaphors, it can express responsibilities and collaborations among work units as classes. The technique yields a detailed Mark breakdown structure, accelerates development of more concise contrast language for follow-up work, improves level-of-effort estimates for future work, and enables continuous process improvement. The process definition technique also introduces team members to OOT principles and concepts.
The paper describes the structure of an environment for a design system based on a design plan, which represents a design process. The approach presented establishes a flexible structure, which improves and integrates...
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The paper describes the structure of an environment for a design system based on a design plan, which represents a design process. The approach presented establishes a flexible structure, which improves and integrates the usage of software tools available in the design process. Possible design plan topologies, the plan generation and exploitation issues are discussed. The structure of the prototype model has been realized in a relational database environment. The potentials of an object-oriented approach to design process planning are analysed, as well as the possible strategies for improving the prototype procedure. Proposals for structuring a design plan with objects and classes are presented.
This paper presents an extensible object model for gas turbine engine performance simulation. The extension method for gas path balancing is analyzed and a new design rationale is developed to overcome deficiencies of...
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This paper presents an extensible object model for gas turbine engine performance simulation. The extension method for gas path balancing is analyzed and a new design rationale is developed to overcome deficiencies of the traditional component-based object modeling method. A class framework implementing this rationale is described and the dynamic performance of a three-shaft gas turbine engine is simulated to evaluate the model's effectiveness. (C) 2000 Elsevier Science Ltd. All rights reserved.
The objectorientedprogramming technique can greatly improve the implementation efficiency, extendibility and ease of maintenance of large engineering software. In this paper, an object-oriented framework for impleme...
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The objectorientedprogramming technique can greatly improve the implementation efficiency, extendibility and ease of maintenance of large engineering software. In this paper, an object-oriented framework for implementing the finite element method is presented. The framework was designed to exploit the commonalties in the methodology between the numerous types of analysis, applied loads, constraints and equation solving algorithms so that duplication is minimized and software reuse is maximized when new capabilities are added to the software. Furthermore, the framework ensures that minimal or no modifications are required to previously implemented functions and classes when the software is extended. (C) 2001 Elsevier Science Ltd. All rights reserved.
This research work aims to develop an intelligent knowledge-based system that accomplishes an environment to assist inexperienced users to estimate the manufacturing cost modelling of a product at the conceptual desig...
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This research work aims to develop an intelligent knowledge-based system that accomplishes an environment to assist inexperienced users to estimate the manufacturing cost modelling of a product at the conceptual design stage of the product life cycle. Therefore, a quicker response to customers' expectations is generated. This paper discusses the development process of the proposed system for cost modelling of machining processes. Tt embodies a CAD solid modelling system, user interface, material selection, process/machine selection, and cost estimation techniques. The main function of the system, besides estimating the product cost, is to generate initial process planning includes generation and selection of machining processes, their sequence and their machining parameters. Therefore, the developed system differs from conventional product cost estimating systems, in that it is structured to support concurrent engineering. Manufacturing knowledge is represented by hybrid knowledge representation techniques, such as production rules, frames and objectoriented. To handle the uncertainty in cost estimation model that cannot be addressed by traditional analytical methods, a fuzzy logic-based knowledge representation is implemented in the developed system. Based on the analysis of product life cycle, the estimated cost included material, processing, machine set-up and non-productive costs. A case study is discussed and demonstrated to validate the proposed system. (C) 2001 Elsevier Science Ltd. All rights reserved.
Traceability ensures that software artifacts of subsequent phases of the development cycle are consistent. Few works have so far addressed the problem of automatically recovering traceability links between object-orie...
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Traceability ensures that software artifacts of subsequent phases of the development cycle are consistent. Few works have so far addressed the problem of automatically recovering traceability links between object-oriented (OO) design and code entities. Such a recovery process is required whenever there is no explicit support of traceability from the development process. The recovered information can drive the evolution of the available design so that it corresponds to the code, thus providing a still useful and updated high-level view of the system. Automatic recovery of traceability links can be achieved by determining the similarity of paired elements from design and code. The choice of the properties involved in the similarity computation is crucial for the success of the recovery process. In fact, design and code objects are complex artifacts with several properties attached. The basic anchors of the recovered traceability links should be chosen as those properties (or property combinations) which are expected to be maintained during the transformation of design into code. This may depend on specific practices and/or the development environment, which should therefore be properly accounted for. In this paper different categories of basic properties of design and code entities will be analyzed with respect to the contribution they give to traceability recovery. Several industrial software components will be employed as a benchmark on which the performances of the alternatives are measured. (C) 2001 Elsevier Science B.V. All rights reserved.
We describe an object-oriented MATLAB toolbox for solving differential equations on manifolds. The software reflects recent development within the area of geometric integration. Through the use of elements from differ...
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We describe an object-oriented MATLAB toolbox for solving differential equations on manifolds. The software reflects recent development within the area of geometric integration. Through the use of elements from differential geometry, in particular Lie groups and homogeneous spaces, coordinate free formulations of numerical integrators are developed. The strict mathematical definitions and results are well suited for implementation in an object-oriented language, and, due to its simplicity, the authors have chosen MATLAB as the working environment. The basic ideas of DiffMan are presented, along with particular examples that illustrate the working of and the theory behind the software package. (C) 2001 IMACS. Published by Elsevier Science B.V. All rights reserved.
The object-oriented programming (OOP) language systems tend to perform object creation and deletion prolifically. An empirical study has shown that C++ programs can have 10 times more memory allocation and deallocatio...
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The object-oriented programming (OOP) language systems tend to perform object creation and deletion prolifically. An empirical study has shown that C++ programs can have 10 times more memory allocation and deallocation than comparable C programs. However, the allocation behavior of C++ programs is rarely reported. This paper attempts to locate where the dynamic memory allocations are coming from and report an empirical study of the allocation behavior of C++ programs. Firstly, this paper summarizes the hypothesis of situations that invoke the dynamic memory management explicitly and implicitly. They are: constructors, copy constructors, overloading assignment operator=, type conversions and application-specific member functions. Secondly, the development of a source code level tracing tool is reported as a procedure to investigate the hypothesis. Most of the five C++ programs traced are real-world applications. Thirdly, allocation patterns, object size and age distribution are summarized. Among other things, we found that objects tend to have a very short life-span, and most of them are created through constructors and copy constructors. With these findings, we may improve the performance of dynamic memory management through, a profile-based strategy or reusing objects. (C) 2001 Elsevier Science Inc. All rights reserved.
The role of stress analysis in design is limited by the batch processing of single design geometries when subjected to prescribed load cases. While this approach is reasonable for detailed design, it limits the engine...
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The role of stress analysis in design is limited by the batch processing of single design geometries when subjected to prescribed load cases. While this approach is reasonable for detailed design, it limits the engineer in early stage design, when rapid availability of stress information for different geometries is perhaps more important than geometric precision. This paper presents structural re-analysis in a boundary element context, providing information on a suitable object-oriented structure, and giving details on the operations required when processing various types of re-analysis. Computational performance improvements (over a full analysis) of 50-80% are found, depending on the degree of perturbation to a pre-existing boundary element method model. An illustration, in which multiple modifications are made to different parts of a design geometry, shows how stress reduction and weight reduction may be achieved as analysis results guide the design in the concept stage. (C) 2001 Elsevier Science Ltd. All rights reserved.
object-oriented programming has already shown to provide numerical scientists with adequate means for improving modularity in basic linear finite element codes. It is demonstrated here that this holds for nonlinear an...
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object-oriented programming has already shown to provide numerical scientists with adequate means for improving modularity in basic linear finite element codes. It is demonstrated here that this holds for nonlinear analysis, provided that the right types of objects with adequate capabilities are defined for handling nonlinear behaviours. In order to implement nonlinear models together with alternative methods for solution control, for nonlinear equation solving and for linear equation solving, a set of three classes is introduced: Problem, Nonlinear-Solver and LinearSolver. C++ examples implementing advanced algorithms indicate that these classes achieve a fair degree of programming flexibility and reusability. They thus provide an appropriate basis for modular nonlinear finite element programming. (C) 1998 Elsevier Science Ltd. All rights reserved.
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