We present an object-oriented framework, named DOOLINES , for non-linear static and dynamic analyses of slender marine structures which often appear in offshore structures employed in the petroleum and gas industries ...
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We present an object-oriented framework, named DOOLINES , for non-linear static and dynamic analyses of slender marine structures which often appear in offshore structures employed in the petroleum and gas industries as, among others, flexible risers, steel catenary risers, umbilicals, floating hoses, and mooring lines. DOOLINES allows the rapid development of tailored, modular, reusable and extensible large-size systems, being itself extensible. These properties, along with the ease of use of our framework, are assessed by means of case studies. Code examples are provided.
At the conceptual design stage, automobile body is evaluated by simplified frame structure, consisting of thin-walled beams (TWBs). In the automobile practice, design engineers mostly rely on their experience and intu...
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At the conceptual design stage, automobile body is evaluated by simplified frame structure, consisting of thin-walled beams (TWBs). In the automobile practice, design engineers mostly rely on their experience and intuition when making decisions on cross-sectional shape of TWBs. So this paper presents a cross-sectional shape optimization method in order to achieve a high stiffness and lightweight TWB. Firstly, cross-sectional property formulations is summarized and reviewed. Secondly, we build up a shape optimization model to minimize the cross-sectional area and satisfy the stiffness and manufacturing demands. The objective and constraints are nonlinear polynomial functions of the point coordinates defining the cross-sectional shape. Genetic algorithm is introduced to solve this nonlinear optimization problem. Thirdly, object-oriented programming and design patterns are adopted to design and implement the software framework. Lastly, numerical example is used to verify the presented method. This software, "SuperBeam" for short, is released for free and does speed up the conceptual design of automobile body. (C) 2013 Elsevier Ltd. All rights reserved.
作者：
Xu, DXNanjing Univ
Dept Comp Sci & Technol State Key Lab Novel Software Technol Nanjing 210093 Peoples R China
This article presents an object-oriented logic framework, I,KO, for the dependable development of knowledge based systems. Based on logical objects which are viewed as abstractions with states, constraints, behaviors ...
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This article presents an object-oriented logic framework, I,KO, for the dependable development of knowledge based systems. Based on logical objects which are viewed as abstractions with states, constraints, behaviors and nonmonotonic inheritance, a hybrid knowledge representation amalgamating rule, frame, semantics network and blackboard is available for both most structured end flat knowledge and requirements of knowledge based systems. After the iterations of specification modification and verification in terms of knowledge acquisition activities, prototypes are correctly formed. The LKO methodology, applying the concepts of rapid prototyping, top-down design and object-orientation, is designed to deal with changing and incomplete requirements and to provide multiple abstract models of the domain, where formal methods might be used at each abstract level. (C) 1998 Elsevier Science B.V. All rights reserved.
Developing interactive software systems with complex user interfaces has become increasingly common. Given this trend, it is important that new technology be based on flexible architectures that do not require develop...
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Developing interactive software systems with complex user interfaces has become increasingly common. Given this trend, it is important that new technology be based on flexible architectures that do not require developers to understand all the complexities inherent in a system. object-oriented frameworks provide an important enabling technology for reusing both the architecture and the functionality of software components. But frameworks typically have a steep learning curve since the user must understand the abstract design of the underlying framework as well as the object collaboration rules or contracts-which are often not apparent in the framework interface-prior to using the framework. In this article, the author describes her experience with developing an object-oriented framework for speech recognition applications that use IBM's ViaVoice speech recognition technology. Design patterns help to effectively communicate the internal framework design and reduce dependence on the documentation.
This paper presents techniques for solving systems of equations arising in finite element applications using a localized, tensor-based approach. The approach is localized in that a major part of the solution responsib...
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This paper presents techniques for solving systems of equations arising in finite element applications using a localized, tensor-based approach. The approach is localized in that a major part of the solution responsibility is delegated to vector degree-of-freedom objects, rather than residing solely in a global solver working on a monolithic data structure. The approach is tensor-based in that the fundamental quantities used for computation are considered to be second-order tensors. The localized data structure strategy provides the benefits of an efficient sparse and symmetric storage scheme without requiring complex implementation code. The tensor-based aspect of the approach can bring substantial performance benefits by increasing the granularity at which solution algorithms deal with their data. Java and C++ implementations of interactive finite element programs are used to demonstrate performance that is competitive with other available solvers, especially in the case of problems for which interactive analysis is feasible on commonly available hardware. (C) 2003 Elsevier Science Ltd. All rights reserved.
Alarm processing is a traditional feature of energy-management systems (EMS), and has not changed significantly over several generations of SCADA design. This paper describes two parts of a project between the Univers...
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Alarm processing is a traditional feature of energy-management systems (EMS), and has not changed significantly over several generations of SCADA design. This paper describes two parts of a project between the University of Dundee and Scottish Hydro-Electric pie (HE) on the use of an Artificial Intelligence system for alarm processing and fault diagnosis. The first part of the project was an overview and comparison study of three real-time object-oriented toolkits: Muse, Kappa and Nexpert object. The study is based on the capabilities of such toolkits to handle the power system alarm processing, integration with external programs and real-time databases, portability, price and execution speed. Some advantages and drawbacks of each toolkit are also pointed out. The second part of the project was the implementation of an object-oriented expert system using the KappaPC toolkit operating on a 486 IBM compatable PC under Microsoft Windows 3.1. The toolkit was chosen in the first part of the project, for the initial development of a prototype real-time alarm-processing and fault-diagnosis system. The structure of the object-oriented expert system captures the heuristic knowledge used for power system operation. The knowledge-base is automatically updated by the existing SCADA system as the power system's status changes. The paper also describes the features of the real-time object-oriented expert system;these include the need for fast, deep-level reasoning, easy maintainability of the object-oriented programming and the end user's interface.
At the conceptual design stage, simplified finite element (FE) model of body-in-white (BIW) structure focuses on its specific merit to provide early-stage predictions for detailed FE model of that. This paper exploits...
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At the conceptual design stage, simplified finite element (FE) model of body-in-white (BIW) structure focuses on its specific merit to provide early-stage predictions for detailed FE model of that. This paper exploits a semi-rigid beam element (SRBE) that consists of a beam element with two semi-rigid connections at the ends to simulate the flexibility of joint. Guyan reduction method condenses the SRBE as a super element. A special finite element software for structural modeling and analysis of BIW (SMAB) is developed in .NET framework. The Unified Modeling Language is employed to depict the classes and their relationship. The design patterns are identified and applied in the framework design to facilitate communication and system expansion. Microsoft DirectX and GDI+ implement graphics display of spatial BIW frame and planar thin-walled cross section. Based on multi-threaded technology in .NET, subspace iteration method is paralleled to speed up the mode analysis. As a result, the efficiency of the SRBE is demonstrated by a benchmarking automotive body. Multi-threaded parallel is effective and useful, especially for frequency optimization. (C) 2011 Elsevier Ltd. All rights reserved.
An agent-based object-oriented model for the fuel distribution network in coastal British Columbia in Canada is presented. objects representing infrastructure components with varied attributes and behaviors are descri...
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An agent-based object-oriented model for the fuel distribution network in coastal British Columbia in Canada is presented. objects representing infrastructure components with varied attributes and behaviors are described together with objects representing transportation modes on land and on water. A novel feature of the modeling approach is its capacity to represent the diverse nature of the objects in a network. Another novelty of the approach is its capacity to simulate discrete deliveries based on requests, which is a requirement in the modeling of the considered fuel distribution network. This paper presents the software architecture and applies it to assess the probability of fuel shortages following an earthquake for six storage facilities in coastal British Columbia. The results of this assessment can be used to inform emergency response plans.
Purpose The purpose of this paper is to evaluate the capabilities of the generalized finite element method (GFEM) under the context of the geometrically nonlinear analysis. The effect of large displacements and deform...
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Purpose The purpose of this paper is to evaluate the capabilities of the generalized finite element method (GFEM) under the context of the geometrically nonlinear analysis. The effect of large displacements and deformations, typical of such analysis, induces a significant distortion of the element mesh, penalizing the quality of the standard finite element method approximation. The main concern here is to identify how the enrichment strategy from GFEM, that usually makes this method less susceptible to the mesh distortion, may be used under the total and updated Lagrangian formulations. Design/methodology/approach An existing computational environment that allows linear and nonlinear analysis, has been used to implement the analysis with geometric nonlinearity by GFEM, using different polynomial enrichments. Findings The geometrically nonlinear analysis using total and updated Lagrangian formulations are considered in GFEM. Classical problems are numerically simulated and the accuracy and robustness of the GFEM are highlighted. Originality/value This study shows a novel study about GFEM analysis using a complete polynomial space to enrich the approximation of the geometrically nonlinear analysis adopting the total and updated Lagrangian formulations. This strategy guarantees the good precision of the analysis for higher level of mesh distortion in the case of the total Lagrangian formulation. On the other hand, in the updated Lagrangian approach, the need of updating the degrees of freedom during the incremental and iterative solution are for the first time identified and discussed here.
Empirical validation of code metrics has a long history of success. Many metrics have been shown to be good predictors of external features, such as correlation to bugs. Our study provides an alternative explanation t...
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Empirical validation of code metrics has a long history of success. Many metrics have been shown to be good predictors of external features, such as correlation to bugs. Our study provides an alternative explanation to such validation, attributing it to the confounding effect of size. In contradiction to received wisdom, we argue that the validity of a metric can be explained by its correlation to the size of the code artifact. In fact, this work came about in view of our failure in the quest of finding a metric that is both valid and free of this confounding effect. Our main discovery is that, with the appropriate (non-parametric) transformations, the validity of a metric can be accurately (with R-squared values being at times as high as 0.97) predicted from its correlation with size. The reported results are with respect to a suite of 26 metrics, that includes the famous Chidamber and Kemerer metrics. Concretely, it is shown that the more a metric is correlated with size, the more able it is to predict external features values, and vice-versa. We consider two methods for controlling for size, by linear transformations. As it turns out, metrics controlled for size, tend to eliminate their predictive capabilities. We also show that the famous Chidamber and Kemerer metrics are no better than other metrics in our suite. Overall, our results suggest code size is the only "unique" valid metric.
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