动态角色体系结构与算法研究

引入新一代动态角色系统概念构建VR仿真场景.首先提出了动态角色层概念,解决了传统方法中存在的接口混乱,资源浪费等问题;然后,通过虚拟环境编辑器管理和构建虚拟角色,将其摆放到合适的位置.并具体介绍了动态角色体系结构(动态角色库管理器、动态角色代理器以及工程项目)和工作流程,系统中属性库更新通过OSG(Open Scene Graph)编程实现(给出了实例飞机飞行计划模拟的方法和流程图),软件研发成果可以通过这样的动态角色系统得到很好的保障.     

一种电子邮件网络的加权演化模型与仿真

本文中提出了一种电子邮件网络加权动态演化模型,它通过生成和删除两种机制来模拟用户定期整理其地址簿的行为,模拟了真实电子邮件网络拓扑结构的动态演化.并通过仿真实验研究了不同演化机制对该网络中3个重要的属性的影响.     

主要用能产品和设备能效信息数据库管理系统的设计

为了解决在信息管理系统中要求数据库表结构可动态修改的问题,结合数据表结构和面向对象编程的技术特点,提出了一种动态数据库表结构设计思路.首先定义了一个可视化的控件类,利用该类型控件与数据表结构字段属性建立关联,通过调整该控件属性,动态生成SQL语句,最后借助一个界面设计工具,实现了动态维护数据库表结构的功能,详细阐述了其在能效信息数据库管理系统中的实现过程,着重介绍了该系统实现过程中解决的关键技术点,为主要用能产品和设备能效技术的研究提供了一个有效的管理工具和技术手段.     

动态战场电磁环境分布式仿真试验系统

该文通过分析电子情报侦察机的仿真试验需求,选择“实物在回路中”的仿真试验模式,介绍基于此模式而设计的动态战场电磁环境分布式仿真试验系统的框架结构,阐述了各分系统的功能和内涵,文中重点说明同步仿真各分系统的方法和动态场景编辑的软件结构。该系统具有模拟近似实战条件下的动态战场电磁环境功能,可用于定量检验基于多种平台的电子情报侦察机的战术技术性能和作战适应能力。     

基于角色访问控制的动态建模

基于角色的访问控制（RBAC）技术随着网络的迅速发展而发展，在RBAC中，角色是重要概念，它根据用户在组织内所处的角色进行访问授权与控制，通过角色沟通主体与客体，已有的RBAC模型往往忽略了角色的动态特征，介绍了一种动态模型，提出角色登台（Role-PLAYing)以实现特定语境中激活角色的动态特征和用户的交互，该模型适合分布式交互式应用系统，并能提高系统的访问控制效率。     

基于分形几何的动态云模拟

云是一种重要的自然景观。对云彩的模拟在视景仿真系统、计算机游戏、三维动画中有着广泛的应用。该文针对目前一些云彩模拟方法中存在的实现复杂、计算耗时、图像分辨力不高且只能生成静态云等问题,提出了一种在分形几何的Diamond—Square算法中采用改良的随机数发生器和顶点扰动、纹理运动结合模拟实现动态云的方法。基本思想是通过运用二次随机法构造改良的随机数发生器,并把它应用到分形几何的Diamond—Square算法中生成逼真的静态云图,然后通过顶点扰动、纹理运动结合模拟实现动态云。最后运用VC＋＋和OpenGL开发工具实现了云的动态模拟。结果表明,该方法实现简单,可获得实时、逼真的动态云效果。     

基于非线性工艺规划思想的车间动态调度系统

描述了一种基于非线性工艺规划思想的车间动态调度系统的集成框架结构，其核心模块为计划调度模块，该模块调用由遗传算法和启发式调度相结合的调度算法生成动态调度方案。其中所提出的遗传编码的设计充分考虑工艺路径的柔性，并根据此编码提出调度方案的构造方法，同时相应地改进了遗传操作，从而实现了调度的全局最优性和可行性。     

面向用户属性的RBAC模型

在传统的RBAC模型中,用户与角色间的关系是静态对应的.针对这一缺点,提出了一种面向用户属性的RBAC模型,在原有RBAC模型的基础上添加了属性集合和约束.在该模型中,根据用户属性动态构造用户与角色的关系,重点讨论了该模型的特征与约束,最后说明了该模型的访问控制实现过程.与普通RBAC模型相比,该模型可以动态根据用户属性分配角色.     

基于Windows 平台的动态取证系统

针对目前一些动态取证模型的不足,在分布式网络取证模型的基础上设计了一个基于Windows平台的动态取证系统,能够实现网络中的计算机作为作案目标和作案工具双重角色时的取证,具有实时获取多种数据源、取证过程隐秘、取证分析算法可扩展等特点。介绍了动态取证系统中各功能模块设计,并阐述了系统设计中涉及到的关键技术,最后通过模拟测试表明该系统能够在Windows网络下实现动态取证。     

带属性策略的RBAC权限访问控制模型

传统基于角色的访问控制(RBAC)不能很好地解决多方访问控制下信任等级的细粒度区分.本文对多种角色访问控制模型及属性特征进行了研究,提出基于属性策略的RBAC模型,对模型进行了形式化定义.在基于属性策略的RBAC模型中,扩展了RBAC中角色的概念,对角色的属性进行了定义并提供基于属性策略的验证方式,进而给出了多方精确访问控制的实现,提高了访问控制的灵活性和对数据对象粒度控制的精确性.在云计算平台上,设计并实现了SaaS模式下的细粒度对象管理服务,实验验证了该模型对动态权限变化的适应能力及多方访问的权限控制能力.     

基于非功能性特征的软件动态自演化框架

针对软件系统的动态自适应演化要求,提出一个基于非功能性特征的软件动态自演化框架。该框架将非功能性特征与不同目标的方面实现相关联,刻画它们之间的正负影响及权衡关系,并通过对方面实现的动态编织实现动态自演化。实验结果表明,该框架是有效可行的。     

一种快速构建Web动态查询系统新型平台的设计与实现

研究了查询构建平台的当今发展现状,设计和实现了一个新型的平台,该平台可以快速构建Web动态查询系统.在设计过程中,组合运用了多种设计方法,其中又以面向对象为主;充分利用流行架构支持不同功能层次,实现在系统的分层实现;系统的实现采用了面向对象的编程方法.该平台可以灵活快速地构建可移植、可定制、高可用性的Web动态查询系统,极大地减少了Web查询系统的开发与维护工作.     

A Dynamic Integrated Framework for Software Process Improvement

Current software process models (CMM, SPICE, etc.) strongly recommend the application of statistical control and measure guides to define, implement, and evaluate the effects of different process improvements. However, whilst quantitative modeling has been widely used in other fields, it has not been considered enough in the field of software process improvement. During the last decade software process simulation has been used to address a wide diversity of management problems. Some of these problems are related to strategic management, technology adoption, understanding, training and learning, and risk management, among others. In this work a dynamic integrated framework for software process improvement is presented. This framework combines traditional estimation models with an intensive utilization of dynamic simulation models of the software process. The aim of this framework is to support a qualitative and quantitative assessment for software process improvement and decision making to achieve a higher software development process capability according to the Capability Maturity Model. The concepts underlying this framework have been implemented in a software process improvement tool that has been used in a local software organization. The results obtained and the lessons learned are also presented in this paper.     

A Foundation of Solution Methods for Constraint Hierarchies

Constraint hierarchies provide a framework for soft constraints, and have been applied to areas such as artificial intelligence, logic programming, and user interfaces. In this framework, constraints are associated with hierarchical preferences or priorities called strengths, and may be relaxed if they conflict with stronger constraints. To utilize constraint hierarchies, researchers have designed and implemented various practical constraint satisfaction algorithms. Although existing algorithms can be categorized into several approaches, what kinds of algorithms are possible has been unclear from a more general viewpoint. In this paper, we propose a novel theory called generalized local propagation as a foundation of algorithms for solving constraint hierarchies. This theory formalizes a way to express algorithms as constraint scheduling, and presents theorems that support possible approaches. A benefit of this theory is that it covers algorithms using constraint hierarchy solution criteria known as global comparators, for which only a small number of algorithms have been implemented. With this theory, we provide a new classification of solution criteria based on their difficulties in constraint satisfaction. We also discuss how existing algorithms are related to our theory, which will be helpful in designing new algorithms.     

基于动态描述逻辑的作物系统模拟框架本体研究

作物系统模拟框架是构建作物生长模型和设计可重用的作物模拟软件的基础框架。作物系统模拟是一个动态过程,传统的本体表示方法无法准确描述。本文对作物系统模拟框架进行形式化的表示,通过分析不同作物模拟过程的作物、子模型和算法之间的关系,给出了动态描述逻辑的逻辑表示,有利于模型之间交流、互操作和重用。     

基于虚拟仪器的车辆零部件应力测试及疲劳强度分析系统

通过对试验测试、计算机仿真以及试验与计算机仿真混合模拟的方法比较分析确定动应力时间历程的选择,利用多数据采集卡的协同工作实现多通道数据采集,以虚拟仪器为基础,LabVIEW软件为开发平台,结合NI的硬件实现了动应力信号数据采集分析,利用LabVIEW的振动疲劳分析包FatigueStartUpKit,搭建了基于虚拟仪器的轨道车辆零部件动应力测试及疲劳强度分析系统,为轨道车辆零部件的相关试验测试提供便捷、准确、可靠的测量方法。     

一种支持动态演化的防火墙软件的设计与实现

对于软件防火墙,如果具备了动态更新的能力,会使被保护的系统更安全,即使在更新时也能对被保护系统进行保护.为达到这一目的,在分析ncffihcr和OSGi框架的原理的基础上,提出采用这两种框架分别处理防火墙安全策略和功能模块更新的方案,实现了一种基于这两种框架的支持动态演化的防火墙系统.     

Perfect class hashing and numbering for object‐oriented implementation

Late binding and subtyping create run‐time overhead for object‐oriented languages, especially in the context of both multiple inheritance and dynamic loading, for instance for JAVA interfaces. In a previous article, we proposed a novel approach based on perfect hashing and truly constant‐time hashtables for implementing subtype testing and method invocation in a dynamic loading setting. In this first study, we based our efficiency assessment on Driesen's abstract computational model for the time aspect, and on large‐scale benchmarks for the space aspect. The conclusions were that the technique was promising but required further research in order to assess its scalability. This article presents some new results on perfect class hashing that enhance its interest. We propose and test both new hashing functions and an inverse problem that amounts to selecting the best class identifiers in order to minimize the overall hashtable size. This optimizing approach is proven to be optimal for single‐inheritance hierarchies. Experiments within an extended testbed with random class loading and under cautious assumptions about what should be a sensible class‐loading order show that perfect class hashing scales up gracefully, especially on JAVA ‐like multiple‐subtyping hierarchies. Furthermore, perfect class hashing is implemented in the PRM compiler testbed, and compared here with the coloring technique, which amounts to maintaining the single‐inheritance implementation in multiple inheritance. The overall conclusion is that the approach is efficient from both time and space standpoints with the bit‐wise and hashing function. In contrast, the poor time efficiency of modulus hashing function on most processors is confirmed. Copyright © 2010 John Wiley & Sons, Ltd.     

Dynamic intermittent Q‐learning–based model‐free suboptimal co‐design of ‐stabilization

This paper proposes an intermittent model‐free learning algorithm for linear time‐invariant systems, where the control policy and transmission decisions are co‐designed simultaneously while also being subjected to worst‐case disturbances. The control policy is designed by introducing an internal dynamical system to further reduce the transmission rate and provide bandwidth flexibility in cyber‐physical systems. Moreover, a Q‐learning algorithm with two actors and a single critic structure is developed to learn the optimal parameters of a Q‐function. It is shown by using an impulsive system approach that the closed‐loop system has an asymptotically stable equilibrium and that no Zeno behavior occurs. Furthermore, a qualitative performance analysis of the model‐free dynamic intermittent framework is given and shows the degree of suboptimality concerning the optimal continuous updated controller. Finally, a numerical simulation of an unknown system is carried out to highlight the efficacy of the proposed framework.     

Developing dynamic‐reconfigurable communication protocol stacks using Java

This paper proposes the development of a dynamic‐reconfigurable protocol stack, which allows the programmer to create, to remove, and to replace protocol modules during their operation. Moreover, this protocol stack also aims to preserve the module state, such as the data structures that manage the existing connections. To achieve these goals, a Java‐based component framework is developed so that the programmers are able to implement their components under the proposed framework. This framework can dynamically reconfigure the components at a safe period and can help the components transfer their states, and the dynamic reconfiguration is transparent to the user application running on top of the stack. To demonstrate the component framework, a TCP component is implemented. While maintaining active connections for the user application, the TCP component is able to be dynamically replaced by another version. Copyright © 2005 John Wiley & Sons, Ltd.