Object-oriented task analysis

The object-oriented approach has recently received much attention in MIS development. However, as yet little research has been reported on task analysis in the object-oriented paradigm. This paper describes an object-oriented method for task analysis. Three fundamental types of objects (task, user, and interface) engaged in task analysis are described. The association between these objects is then built through identifying the messages between the objects. A practical application of this method shows that it is useful for the analysis and design of a human-computer interface.     

Object-oriented analysis-synthesis coding based on moving two-dimensional objects

An object-oriented analysis-synthesis coder is presented which encodes arbitrarily shaped objects instead of rectangular blocks. The objects are described by three parameter sets defining their motion, shape and colour. Throughout this contribution, the colour parameters denote the luminance and chrominance values of the object surface. The parameter sets of each object are obtained by image analysis based on source models of moving 2D-objects and coded by an object-dependent parameter coding. Using the coded parameter sets an image can be reconstructed by model-based image synthesis. In order to cut down the generated bit-rate of the parameter coding, the colour updating of an object is suppressed if the modelling of the object by the source model is sufficiently exact, i.e., if only a relatively small colour update information would be needed for an errorless image synthesis. Omitting colour update information, small position errors of objects denoted as geometrical distortions are allowed for image synthesis instead of quantization error distortions. Tolerating geometrical distortions, the image area to be updated by colour coding can be decreased to 4% of the image size without introducing annoying distortions. As motion and shape parameters can efficiently be coded, about 1 bit per pel remains for colour updating in a 64 kbit/s coder compared to about 0.1 bit per pel in the standard reference coder (RM8) of the CCITT. Experimental results concerning the efficient coding of motion and shape parameters are given and discussed. The coding of the colour information will be dealt with in further research.     

基于面向对象的模具产品数据管理系统信息模型研究

在深入分析模具制造过程及其信息结构特点的基础上 ,运用面向对象建模技术 ,研究模具产品数据管理系统基本对象模型和对象属性模型的结构及其相互关系 ;并根据集成模具产品数据管理系统的功能需求 ,构建了模具产品数据管理系统的信息模型 ,为模具产品数据管理系统的结构设计与功能规划及进一步的系统开发提供了技术支持。     

An open source, parallel DSMC code for rarefied gas flows in arbitrary geometries

This paper presents the results of validation of an open source Direct Simulation Monte Carlo (DSMC) code for general application to rarefied gas flows. The new DSMC code, called dsmcFoam, has been written within the framework of the open source C++ CFD toolbox OpenFOAM. The main features of dsmcFoam code include the capability to perform both steady and transient solutions, to model arbitrary 2D/3D geometries, and unlimited parallel processing. Test cases have been selected to cover a wide range of benchmark examples from 1D to 3D. These include relaxation to equilibrium, 2D flow over a flat plate and a cylinder, and 3D supersonic flows over complex geometries. In all cases, dsmcFoam shows very good agreement with data provided by both analytical solutions and other contemporary DSMC codes.     

基于面向对象遗传算法的柔性车间调度研究

针对柔性车间作业调度问题,基于面向对象思想设计了一种遗传算法。该算法将实际操作封装成基因类,工件封装成工件类,机床封装成机床类,调度方案封装成染色体类,基于堆栈思想设计了染色体的创建方式,提出了全新的染色体解码方式及变异方式。通过仿真实例证明了该算法的有效性和实用性。     

Security requirement analysis of business processes

Economic globalization leads to complex decentralized company structures calling for the extensive use of distributed IT-systems. The business processes of a company have to reflect these changes of infrastructure. In particular, due to new electronic applications and the inclusion of a higher number of—potentially unknown—persons, the business processes are more vulnerable against malicious attacks than traditional processes. Thus, a business should undergo a security analysis. Here, the vulnerabilities of the business process are recognized, the risks resulting from the vulnerabilities are calculated, and suitable safeguards reducing the vulnerabilities are selected. Unfortunately, a security analysis tends to be complex and affords expensive security expert support. In order to reduce the expense and to enable domain experts with in-depth insight in business processes but with limited knowledge about security to develop secure business processes, we developed the framework MoSS_BP facilitating the handling of business process security requirements from their specification to their realization. In particular, MoSS _BP provides graphical concepts to specify security requirements, repositories of various mechanisms enforcing the security requirements, and a collection of reference models and case studies enabling the modification of the business processes. In this paper, the MoSS _BP -framework is presented. Additionally, we introduce a tool supporting the MoSS_BP-related security analysis of business processes and the incorporation of safeguards. This tool is based on object-oriented process models and acts with graph rewrite systems. Finally, we clarify the application of the MoSS_BP-framework by means of a business process for tender-handling which is provided by anonymity-preserving safeguards. Peter Herrmann studied computer science at the University of Karlsruhe, Germany (diploma in 1990). Afterwards, he worked as a Ph.D. student (doctorate in 1997) and postdoctoral researcher in the Computer Networks and Distributed Systems Group of the Computer Science Department at the University of Dortmund, Germany. Since 2005 he is a full professor for formal methods at the Department for Telematics of the Norwegian University of Science and Technology (NTNU) in Trondheim, Norway. His research interests include the formal-based development of networked systems and the engineering of distributed services. Moreover, he is interested in security and trust aspects of component structured distributed software. Gaby Herrmann studied computer science at the University of Karlsruhe, Germany (diploma in 1991). Afterwards, she worked as a researcher in the Communication Group and the Information Systems Group at University of Duisburg-Essen (Doctorate in 2001, topic: security of business processes). Since 2000 she works as executive secretary at the Department of Economics, Business Studies and Computer Sciences at the same university.     

Identification of defect-prone classes in telecommunication software systems using design metrics

The goal of this paper is to investigate the relation between object-oriented design choices and defects in software systems, with focus on a real-time telecommunication domain. The design choices are measured using the widely accepted metrics suite proposed by Chidamber and Kemerer for object oriented languages [S.R. Chidamber, C.F. Kemerer, A metrics suite for object oriented design, IEEE Transactions on Software Engineering 20 (6) (1994) 476-493].This paper reports the results of an extensive case study, which strongly reinforces earlier, mainly anecdotal, evidence that design aspects related to communication between classes can be used as indicators of the most defect-prone classes.Statistical models applicable for the non-normally distributed count data are used, such as Poisson regression, negative binomial regression, and zero-inflated negative binomial regression. The performances of the models are assessed using correlations, dispersion coefficients and Alberg diagrams.The zero-inflated negative binomial regression model based on response for a class shows the best overall ability to describe the variability of the number of defects in classes.     

应用MVC模式开发商务网站的研究

面向对象软件开发方法是当前软件开发领域的主流技术。将此技术应用到开发电子商务系统中 ,用面向对象的开发方法促使软件开发人员按对象是应用领域的观点去思考问题 ,是开发电子商务系统的一种尝试 ,也是必然趋势。在介绍SmalltalkMVC模式之后 ,着重讨论了将MVC模式应用于基于J2EE开发电子商务系统中 ,进行系统设计和对象设计与实现。将整个系统分为 5类对象处理 :View、Controller、Model、DB类对象和例外类对象。具体实现时 ,View类由JSP实现 ,Controller类由Servlet实现 ,Model类由EJB/JavaBean组成 ,DB类由Input ,Data ,Value 3个类处理。一般情况下 ,Controller类操作比较固定 ,其他类针对不同操作对象又进行了类的划分与继承 ,以达到复用性好、易维护、开发高效的要求。最后给出一个示例加以说明     

基于面向对象空间数据库的三维地景可视化研究

该文设计了一个基于面向对象空间数据库的三维地景(terrain)可视化系统,并依据人们对地图的理解角度提出了面向对象的四级数据模型,研究了场景生成技术,开发了底层的面向对象的空间数据库。系统具有良好的通用性和可扩展性,在飞行模拟、实时动态仿真及虚拟现实等领域有较广泛的应用前景。     

面向对象空间数据组织方法与应用研究

文章在空间对象类的组织和管理、空间对象高效的索引方式以及分离空间数据与空间数据应用等方面提出了一些新的观点。