The recent trend in distributed automation and control systems has been towards event-triggered system architectures such as UML and IEC 61499. Although existing communication protocols (e.g., Ethernet) can support hi...
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The recent trend in distributed automation and control systems has been towards event-triggered system architectures such as UML and IEC 61499. Although existing communication protocols (e.g., Ethernet) can support high-level communication within these systems, there is contention as to which low-level protocol to use, or if any exist that meet the requirements of being event-triggered and hard real-time. This paper proposes a new way to measure communication performance. The goal of the new measurement method is to stress the necessity that a real-time communication protocol needs to be both efficient and fair. This is illustrated by comparing three communication strategies: Controller Area Network (CAN), Time-Triggered CAN (TTCAN) and Escalating Priority CAN (EPCAN). The first two represent the extremes between event-triggered and time-triggered communication strategies;the third is introduced to illustrate the benefits of a new event-based communication protocol proposed by the authors. (c) 2010 Elsevier Ltd. All rights reserved.
The paper describes a detailed study into the object-oriented implementation of distributed finite element analysis on desktop computers using the NET framework. The software design aspects are described in some detai...
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The paper describes a detailed study into the object-oriented implementation of distributed finite element analysis on desktop computers using the NET framework. The software design aspects are described in some detail for both direct and iterative solution algorithms. The use of interfaces played an important role in the software design. This, together with the NET framework, enabled remote objects to be implemented in a relatively seamless fashion. The solution routines were "blind" to whether the objects were local or remote. Numerical tests were carried out and reasonable speed-up was achieved, particularly for direct solution methods. It is concluded that NET provides a viable framework for implementing distributed computing on networks of personal computers. (c) 2006 Elsevier Ltd. and Civil-Comp Ltd. All rights reserved.
The aim of the paper is to investigate applicability of object-oriented software design patterns in the context of aspect-oriented design. The paper analyses which of the GoF 23 patterns have a meaning in this context...
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The aim of the paper is to investigate applicability of object-oriented software design patterns in the context of aspect-oriented design. The paper analyses which of the GoF 23 patterns have a meaning in this context and how they are affected by it. The main assumption is that there exist design patterns that solve software engineering paradigm independent design problems and that such patterns, in the contrast to the patterns solving paradigm-specific design problems, can be expressed in terms of any software engineering paradigm. However, the paper deals only with two paradigms: aspect-oriented (AO) paradigm and object-oriented (OO) paradigm. It proposes a classification of design problems based on this assumption and a technique for redesigning object-oriented patterns into pure aspect-oriented ones. It presents a number of examples how to apply this technique and discusses the results obtained. The results show that 20 of the GoF 23 design patterns solve such design problems that are common at least for both mentioned paradigms and demonstrate in which way these patterns can be adapted for the needs of aspect-oriented design.
作者：
Deng, LiangZeng, QingkaiNanjing Univ
State Key Lab Novel Software Technol Nanjing 210023 Jiangsu Peoples R China Nanjing Univ
Dept Comp Sci & Technol Nanjing 210023 Jiangsu Peoples R China
Commodity operating system kernels are vulnerable to a wide range of attacks due to the large code base and broad attack surface. Mitigation mechanisms such as code signing, W circle plus X, and code integrity protect...
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Commodity operating system kernels are vulnerable to a wide range of attacks due to the large code base and broad attack surface. Mitigation mechanisms such as code signing, W circle plus X, and code integrity protection have raised the bar for kernel security. In turn, attack mechanisms have also become increasingly advanced. They have evolved from simple injection of malicious code into more sophisticated code-reuse attacks [e.g. return-orientedprogramming (ROP)]. In this study, the authors describe exception-orientedprogramming (EOP), a novel code-reuse method to construct kernel malware. Unlike previous ROP that can only reuse a limited part of existing code (gadgets), EOP is able to reuse any instruction in existing code and chain the instructions in any order to generate malicious programmes. As a result, EOP can provide the attackers with more powerful capabilities and less complexity for building kernel malware.
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.
Simulation-based optimization for industrial process lines is discussed in this paper. Our approach combines multidisciplinary modeling, modern sensitivity analysis methodology as well as multiobjective optimization b...
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Simulation-based optimization for industrial process lines is discussed in this paper. Our approach combines multidisciplinary modeling, modern sensitivity analysis methodology as well as multiobjective optimization by means of object-oriented software design principles. As a result, a simulation and optimization approach that can be extended and modified due to users' needs can be developed. Our approach is illustrated by a real-world example from papermaking industry.
We describe implementation of a modular system of computer codes for inversion of electromagnetic geophysical data, referred to as ModEM. The system is constructed with a fine level of modular granularity, with basic ...
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We describe implementation of a modular system of computer codes for inversion of electromagnetic geophysical data, referred to as ModEM. The system is constructed with a fine level of modular granularity, with basic components of the inversion - forward modeling, sensitivity computations, inversion search algorithms, model parametrization and regularization, data functionals - interchangeable, reusable and readily extensible. Modular sensitivity computations and generic interfaces to parallelized inversion algorithms provide a ready framework for rapid implementation of new applications or inversion algorithms. We illustrate the code's versatility and capabilities for code reuse through implementation of 3D magnetotelluric (MT) and controlled-source EM (CSEM) inversions, using essentially the same components. (C) 2014 Elsevier Ltd. All rights reserved.
The aim of this paper is to describe an efficient method to connect two independent softwares so as to jointly use best qualities of each software around a complex problem solved by the finite element emethod (FEM). T...
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The aim of this paper is to describe an efficient method to connect two independent softwares so as to jointly use best qualities of each software around a complex problem solved by the finite element emethod (FEM). This connection makes it possible to extend quickly and easily the applicability of new models developed in academic softwares, by their simultaneous use with commercial softwares. This is particularly interesting when these models are vey difficult to implement directly in commercial softwares. Most of the commercial FEM applications allow users to add additional features, physical models or boundary conditions via a programing interface. Within these user routines, access to internal data structures is possible, either through subroutine parameters and global variables, or via internal modules for reading and storing data. We use these capabilities to link the commercial software ABAQUS and an academic object-oriented C++ software HEREZH++, via the user-defined mechanical material behaviour (Umat). In this interface, HEREZH++ computes the mechanical behaviour of material and the code coupling performs a communication procedure between ABAQUS and HEREZH++. This paper describes this architecture which allows to implement easily original behaviour law and an interface written in c/C++. Several test samples are presented to show the efficiency and accuracy of the proposed implementations concernning the computational time. In particular, an industrial test is carried out with an original behaviour model of clasto-viscohysteresis which would have been very difficult to implement directly in ABAQUS. (c) 2008 Elsevier Ltd. All rights reserved.
Semantic Web applications share a large portion of development effort with database-driven Web applications. Existing approaches for development of these database-driven applications cannot be directly applied to Sema...
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Semantic Web applications share a large portion of development effort with database-driven Web applications. Existing approaches for development of these database-driven applications cannot be directly applied to Semantic Web data due to differences in the underlying data model. We develop a mapping approach that embeds Semantic Web data into object-oriented languages and thereby enables reuse of existing Web application frameworks. We analyse the relation between the Semantic Web and the Web, and survey the typical data access patterns in Semantic Web applications. We discuss the mismatch between object-oriented programming languages and Semantic Web data, for example in the semantics of class membership, inheritance relations, and object conformance to schemas. We present ActiveRDF, an object-oriented API for managing RDF data that offers full manipulation and querying of RDF data, does not rely on a schema and fully conforms to RDF( S) semantics. ActiveRDF can be used with different RDF data stores: adapters have been implemented to generic SPARQL endpoints, Sesame, Jena, Redland and YARS and new adapters can be added easily. We demonstrate the usage of ActiveRDF and its integration with the popular Ruby on Rails framework which enables rapid development of Semantic Web applications. (c) 2008 Elsevier B. V. All rights reserved.
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.
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