面向对象的地理遥感信息模型——建模过程

地理遥感信息模型是在地形模型、物理模型、数学模型的基础上提出的一种新型模型。面向对象技术是一种新型的系统建模技术。着重论述了面向对象技术应用于地理遥感信息模型建模的可行性,提出以面向对象技术基本理论为指导,构建面向对象的地理遥感信息模型的建模方法、数据结构以及建模优势。     

智能抄表管理系统软件模型的建模

提出了一种新的智能抄表数据管理方法。依据该方法的思想建立系统的体系结构。进而将面向对象方法学应用于智能抄表管理系统软件的研究和开发。通过面向对象建模技术(OMT)建立该管理系统的软件模型,即面向对象软件的三个子模型———对象模型、动态模型和功能模型。管理系统软件模型的建模过程分为面向对象分析(OOA)和面向对象设计(OOD)两个阶段进行。     

基于改进RBAC模型的访问控制方法

为了解决信息系统访问控制在实际应用中暴露出的授权繁琐、权限控制粒度不足等问题,提出一种改进的RBAC模型;该模型通过增加访问主体的组成粒度并应用面向对象的建模技术对模型中客体对象进行建模描述,提高了系统授权效率并实现了数据级的权限控制;最后给出了该模型的形式化描述和控制算法,并通过在CAPP系统的应用实例验证了该模型的有效性.     

UML在实时系统中的应用研究

UML是最广泛使用的面向对象建模语言,是可视化面向对象系统的建模方法。针对嵌入式系统设计和开发的特点,文中描述了一种将时间组件融入到UML建模中的方法,把时间特性从系统中分离出来。用UML对嵌入式实时系统进行面向对象分析与设计,并以冰箱温度平衡器系统为例,建立了需求分析、静态结构模型和动态行为模型,该方法能够有效地捷高开发效率、改善设计质量。     

UML在实时系统中的应用研究

UML是最广泛使用的面向对象建模语言,是可视化面向对象系统的建模方法.针对嵌入式系统设计和开发的特点,文中描述了一种将时间组件融入到UML建模中的方法,把时间特性从系统中分离出来.用UML对嵌入式实时系统进行面向对象分析与设计,并以冰箱温度平衡器系统为例,建立了需求分析、静态结构模型和动态行为模型,该方法能够有效地提高开发效率、改善设计质量.     

基于分层思想的基本通信系统CPN建模

针对通信系统建模复杂度高、可靠性差、模型缺乏形式化验证方法以及可重用性差的问题,提出一种基于分层思想,并结合面向对象的概念,利用着色Petri网(CPN)对基本通信系统进行建模的方法。该方法融合CPN和面向对象技术的优点,从形式化、可视化的角度描述基本通信系统的运行过程。以一个简单的基本通信系统为例进行建模,证明该模型与实际系统中的对象可以相互对应,易于理解和实现。     

基于Petri Nets的BDI Agent模型

Petri nets是一种图形和数学的建模工具,广泛应用于各种系统。它们主要描述和研究信息处理系统一些特点,如并发、异步、分布、并行、非确定和随机过程。为了更容易、方便、自然地描述agent系统,该文提出了面向agent的Petri nets分析方法。该方法主要对面向对象的Petri nets分析方法作了一些改进。最后给出了基于Petri nets的BDI agent实现模型。     

一种表单驱动的面向对象的逆向建模方法

本文提出一种表单驱动的面向对象的逆向工程建模方法,该方法由五个阶段组成：表单使用分析、表单对象切片、对象结构建模、脚本设计以及模型集成。该方法利用表单结构知识和用户接口信息提取应用的系统的语义。     

一种面向对象的生产系统模拟工具-OSim的开发

介绍了一种面向对象的生产系统模拟工具OSim的体系结构和特点，以及应用Osim进行生产系统建模的方法和过程。面向对象的生产系统模拟模型的开发分为5个步骤：面向过程的建模，面向被动资源的建模，面向主动资源的建模，面向产品／物料的建模，层次化模型的建立。其中，面向对象的技术、基于活动网络的建模和层次化建模在生产系统建模中是非常重要的。     

一种表单驱动的面向对象的逆向建模方法

本文提出一种表单驱动的面向对象的逆向工程建模方法. 该方法由五个阶段组成:表单使用分析、表单对象切片、对象结构建模、脚本设计以及模型集成.该方法利用表单结构知识和用户接口信息提取应用系统的语义.     

3D object model reconstruction from image sequence based on photometric consistency in volume space

This paper presents a system that can reconstruct a photorealistic 3D object model from an image sequence captured at arbitrary viewpoints. The whole system consists of four steps: camera calibration, volumetric modeling, polygonal model formation and texture mapping. We adopt the shape-from-silhouette approach for volumetric modeling. There are two common types of object surface that are difficult to reconstruct—textureless surface and concave surface. To tackle the problems, we propose to perform the volumetric modeling based on the constraints of viewpoint proximity and photometric consistency in the volume space. The volumetric model is converted to the mesh model for efficient manipulation. Finally, the texture map is generated from the image sequence to give the 3D model a photorealistic appearance. Some reconstructed object models are presented to demonstrate the superior performance of our system as compared with the conventional modeling technique based on the photo-consistency in the image space.     

面向软件行为和多视点的需求建模方法

提出一种面向软件行为和多视点的需求建模方法,包括建模步骤和建模语言.其中目标系统根据问题域以及视点源被划分成视点.视点在需求模型中以实体的方式存在,每个视点通过从需求规格说明中提取的场景来描述,作为需求模型基本组成单位的场景模型则通过基本的行为复合而成.分析了基于行为和多视点的需求建模过程,讨论了需求建模语言:行为描述语言的语法和语义,并给出相关实例分析以及所实现的建模工具简介.     

Host-based intrusion detection using dynamic and static behavioral models

Intrusion detection has emerged as an important approach to network security. In this paper, we adopt an anomaly detection approach by detecting possible intrusions based on program or user profiles built from normal usage data. In particular, program profiles based on Unix system calls and user profiles based on Unix shell commands are modeled using two different types of behavioral models for data mining. The dynamic modeling approach is based on hidden Markov models (HMM) and the principle of maximum likelihood, while the static modeling approach is based on event occurrence frequency distributions and the principle of minimum cross entropy. The novelty detection approach is adopted to estimate the model parameters using normal training data only, as opposed to the classification approach which has to use both normal and intrusion data for training. To determine whether or not a certain behavior is similar enough to the normal model and hence should be classified as normal, we use a scheme that can be justified from the perspective of hypothesis testing. Our experimental results show that the dynamic modeling approach is better than the static modeling approach for the system call datasets, while the dynamic modeling approach is worse for the shell command datasets. Moreover, the static modeling approach is similar in performance to instance-based learning reported previously by others for the same shell command database but with much higher computational and storage requirements than our method.     

基于图像序列的虚拟场景重建和漫游

基于图像的建模和绘制方法与基于传统的几何绘制方法相比有很多优点,但是在场景几何参数未知的情况下,要实现单幅图片和图像序列的漫游,难度很大.TIP（tour into a picture）技术使得在一幅图像中漫游成为可能.为了实现场景几何参数未知情况下的场景漫游,在对TIP技术进行扩展的基础上,提出了一种能够在未知视点路径的图像序列中实现场景漫游的方法.这种算法在相机未定标的情况下,不仅解决了图像序列建模和场景漫游过程中前后图像场景不能平滑过渡的问题,并且扩大了TIP中视线方向变化的动态范围,从而在保证图像质量的情况下,实现了由图像序列到场景的无限制漫游.实际图像序列的实验结果表明,该算法是有效的,具有实际应用价值.     

Principle of frequency-domain balanced structure in linear systems and model reduction

In this paper a novel model reduction technique for linear time-invariant systems is presented. The proposed technique is based on a conceptual viewpoint regarding the balancing of the controllability and observability Gramians of a multivariable system in a given range of frequency. The conditions for the stability of the reduced model are also provided. From a real-time applicability viewpoint, the frequency-domain balanced structure provides an attractive approach to the model reduction of large scaled systems. The simulation results establish the effectiveness of this proposed method compared to the effectiveness of existing techniques.     

Object-oriented software modeling of a Flexible Manufacturing System

Flexible Manufacturing Systems play an important role in improving our manufacturing productivity. Simulation is emerging as a popular tool in modeling FMS for analyzing its performance in the area of production planning/scheduling. In this paper, we illustrate how to model a Flexible Manufacturing System in the object-oriented paradigm using an example. We present a systemtic approach to the design of object-oriented programming systems based on a combination of data modeling and event analysis techniques.An entity relationship approach is used as the basis for an initial decomposition of the system into objects. The design is refined by an analysis of the events the objects participate in. The design is implemented in Objective-C. Finally, we describe ways in which this model of an FMS can be extended to explore popular research questions in production planning and scheduling.     

一种支持MDA的模型转换方法

平台无关模型(PIM)到平台有关模型(PSM)的转换是模型驱动体系结构(MDA)中的关键技术，但目前还没有针对该转换的有效的解决方案。从软件工程的实施出发，以抽象代数理论为基础，同时考虑建模元素的语法结构和语义特性，该文提出了一种基于体系结构映射的、可支持模型间自动转换的方法。该方法充分利用软件体系结构在软件开发各阶段间保持的良好可追踪性，使其同时成为系统分析和模型转换的基础。以J2EE目标平台为例说明了该方法的应用。     

Learning probabilistic models for model checking: an evolutionary approach and an empirical study

Many automated system analysis techniques (e.g., model checking, model-based testing) rely on first obtaining a model of the system under analysis. System modeling is often done manually, which is often considered as a hindrance to adopt model-based system analysis and development techniques. To overcome this problem, researchers have proposed to automatically “learn” models based on sample system executions and shown that the learned models can be useful sometimes. There are however many questions to be answered. For instance, how much shall we generalize from the observed samples and how fast would learning converge? Or, would the analysis result based on the learned model be more accurate than the estimation we could have obtained by sampling many system executions within the same amount of time? Moreover, how well does learning scale to real-world applications? If the answer is negative, what are the potential methods to improve the efficiency of learning? In this work, we first investigate existing algorithms for learning probabilistic models for model checking and propose an evolution-based approach for better controlling the degree of generalization. Then, we present existing approaches to learn abstract models to improve the efficiency of learning for scalability reasons. Lastly, we conduct an empirical study in order to answer the above questions. Our findings include that the effectiveness of learning may sometimes be limited and it is worth investigating how abstraction should be done properly in order to learn abstract models.     

INTELLIGENT SYNTAX-DIRECTED EDITOR THAT MODELS USER PROFICIENCY

Current interactive software systems try to offer many features and a user-friendly interface to aid the user. However, where one system may suit one user, another user may find it difficult to use, because each user is different. User modeling techniques have been applied to make a system suitable for different users. This paper surveys research works for developing interactive systems that use user modeling techniques. After presenting the systems and techniques, we introduce a system called the Intelligent Syntax-Directed Editor (ISE) as an example to show how this approach can benefit the user as an intelligent tool. The ISE assists the user in (1) using the editor more efficiently through ISE's active suggestions and on-line help and (2) program development through the syntax-directed editor. In applying user modeling techniques, ISE builds a profile/model of the user and, based on this model, ISE offers a suitable amount of help and advice depending on the proficiency of the user toward the system. The ISE is implemented on a VAX/780 computer to demonstrate its ability to volunteer advice