面向对象的空中交通流量管理系统建模与仿真

针对我国空中交通流量日益增长的空中交通管理的现状,研究建立空中交通流量管理系统,通过监视一定范围的空中交通状况,进行交通流量的预测和控制。面向对象理论已成为复杂系统设计和分析中一种必不可缺的工具,这种技术为交通流量管理系统的研究提供了重要的平台。利用抽象、分类、封装、继承、关联、消息通讯等概念建立的交通流量管理系统的模型结构清晰,更好的反映了系统的工作流程和各模块间的交互关系。     

实用内存数据库核心及其在VLR系统中的应用

从实际应用的角度出发,引出内存数据库的定义及其系统特点,采用面向对象的软件设计方法设计内存数据库的内存组织结构,介绍内存数据库的核心对象并简单说明表对象操作方法的实现过程。结合移动网络中的VLR实体,简单阐述实用内存数据库在通讯领域的应用。     

基于对象的并发模型

为了研究和发展分布式人工智能,探讨一种新的计算模型,利用面向对象技术提出了一个基于对象的并发模型（OBCM）。讨论了它的两种通讯机制,即同步和异步通讯方式,异步通讯方式又分为过去型消息传递和将来型消息传递,而同步通讯方式则包括现在型消息传递和等待方式。证明了它们可归约为过去型消息传递和等待状态。另外,OBCM为了增强其表达能力,提供了响应目的地机制。在OBCM中,对象的独立自治特点对模拟分布式问题求解尤为适用。最后以一个分布式问题求解的具体实例说明了OBCM的思想。     

A semantics of introspection in a reflective prototype-based language

In Malenfant et al. [19], we have described a reflective model for a prototype-based language based on thelookup o apply reflective introspection protocol. In this paper, we augment our previous protocol by converting it to handle continuations reified as first-class objects. First-class continuations provide much more control over the current computation; during the introspection phase fired by message sending, they make it possible not only to change the behavior of the program for that message but also for the entire future computation. In this paper, we provide this introspection protocol with a formal semantics. This result is obtained by exhibiting a mapping from program configurations to priority rewrite systems (PRS) as well as a mapping from message expressions to ground first-order terms used to query the PRS. Other advantages of this approach are: to ensure the termination of the introspection using the smallest set of formally justified conditions and to provide a clear declarative account of this reflective protocol. The PRS also appears as a meta-level to the base language, independent of the implementation, but from which we derive fundamental clues to obtain an efficient language processor. By our new model, we finally highlight the link between reflection in object-oriented languages and the one originally proposed by 3-Lisp [24], although object-orientation provides reusability to reflection, making it easier to use.     

UPE: Utah prototyping environment for robot manipulators

Developing an environment that enables optimal and flexible design of robot manipulators using reconfigurable links, joints, actuators, and sensors is an essential step for efficient robot design and prototyping. Such an environment should have the right mix of software and hardware components for designing the physical parts and the controllers, and for the algorithmic control of the robot modules (kinematics, inverse kinematics, dynamics, trajectory planning, analog control and digital computer control). Specifying object-based communications and catalog mechanisms between the software modules, controllers, physical parts, CAD designs, and actuator and sensor components is a necessary step in the prototyping activities.In this paper, we propose a flexible prototyping environment for robot manipulators with the required subsystems and interfaces between the different components of this environment. This environment provides a close tie between the design parameters of the robot manipulator by the different subsystems involved in the design process. The design and implementation of this environment along with the implementation of some of the subsystems are presented, and some examples that demonstrate the functionality of the environment are discussed. This work was supported in part by DARPA grant N00014-91-J-4123, NSF grant CDA 9024721, and a University of Utah Research Committee grant. All opinions, findings, conclusions or recommendations expressed in this document are those of the author and do not necessarily reflect the views of the sponsoring agencies.     

以实例贯穿课堂的面向对象程序设计课程教学改革

面向对象程序设计课程是当前计算机专业学生的一门必修专业课。课程本身的复杂性与实践性,使学生无法完全理解消化并有效应用所学知识点。针对这种情况,本文研究如何设计简短精悍、适于课堂演练的实例,并将这些实例与理论学习在课堂上有机结合,使学生易于领会知识点、充分参与课堂教学,最终达到学生积极主动学习,对知识点融会贯通的目的。     

基于A-Star算法警用地图查询系统的设计与实现

介绍了一种基于A-Star算法的警用地图查询系统的设计与实现。系统采用了面向对象技术进行程序设计思想,运用A-Star算法实现了对警用地图的数据进行检索和路径分析,为人民警察工作及时出警、精确打击、高效抓捕提供了技术保证。     

特征权重优化高分辨率遥感影像模糊分类研究

在针对SPOT5等高分辨率遥感影像的面向对象模糊分类过程中,一般对影像对象的特征赋予相同的权重。为了体现不同特征对分类作用的差异,本文在分类时根据特征的重要与否,对参与分类的特征赋予不同的权重,提高重要的、区分度好的特征的权重,降低次要特征的权重。以北京市昌平区的SPOT5影像为例,利用多特征模糊分类和经过权重优化的多特征模糊分类进行分类对比实验。实验结果表明,经过特征权重优化的分类与权重相同的分类结果相比,分类总精度由原来的86.3%提高到了92.6%,Kappa系数由原来的0.8096提高到了0.8947。结果表明,经过权重优化的多特征模糊分类有助于提高模糊分类法的分类精度和适用性。     

基于Java的对象模型消息机制实现

Java语言标准不提供消息,使得面向对象模型中消息机制的实现十分不便。针对上述问题,利用Java的接口、继承及多态机制,实现一种风格与微软基础类库中framework的消息机制相似的对象模型消息机制,将其应用于一款基于LEGO机器人的协同式智能化多机器人系统,结果证明该消息机制具有合理性、有效性和易实现性。     

一种类间测试顺序改进算法

确定类的测试顺序是面向对象程序测试中的关键步骤。描述对象关系图模型,提出一种基于对象关系图的类间集成测试顺序改进算法,与Tai和Traon等人提出的算法相比,该算法需要的测试桩较少、效率较高。在Redflag4系统下用Kylix3(C++)对算法进行实现。理论分析和初步实验证明了该算法的可行性和有效性。