Colored timed Petri nets for modeling and analysis of cluser tools

In this paper, a colored timed resource‐oriented Petri net (CTROPN) is developed to model the cluster tools in semiconductor fabrication. It is structurally simple and concise, since each module in a cluster tool corresponds to a unique place in CTROPN. It is also powerful in modeling the qualitative and temporal behavior of the cluster tools with a single‐blade or dual‐blade robot. The initial transient behavior, steady‐state behavior and the final transient behavior can all be investigated through a single model. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society     

基于推荐完整性的电子商务推荐系统架构的设计

针对个性化推荐完整性欠佳的问题,设计一种基于第三方的电子商务推荐架构。使用聚合内容获取信息源,运用多代理实现推荐流程,借助面向对象存储技术在第三方平台扩充备选项集。通过对上述技术方法的组合应用,使推荐的完整性得以提升,克服了传统推荐系统忽略用户站外行为影响推荐完整性的缺陷。     

Finite‐time attitude‐tracking control for rigid spacecraft with actuator failures and saturation constraints

In this article, the problem of finite‐time attitude‐tracking control for rigid spacecraft is addressed. Uncertainties caused by external disturbances, unknown inertial matrix, actuator failures, and saturation constraints are tackled simultaneously. First, a smooth function that is more qualified to approximate the standard saturation characteristics is presented to deal with the actuator saturation constraints. Second, a fast nonsingular terminal sliding mode (FNTSM) manifold is constructed as a foundation of controllers design. By incorporating the fuzzy logic system into FNTSM technique, a less demanding solution of coping with model uncertainties is provided because the requirement of a prior knowledge of unknown inertial parameters and external disturbances in many existing achievements is removed. To reduce the number of parameters to be estimated, the norm approximation approach is exploited. Subsequently, an antichattering attitude controller is presented such that all the tracking errors converge into arbitrary small domains around the origin in finite time. The result is further extended to obtain a fault‐tolerant controller against completely failed actuators. Finally, numerical simulation is conducted to verify the effectiveness of the proposed control scheme and comparison with relevant literature demonstrates its high performance. Furthermore, an experiment for the large satellite Hubble Space Telescope is carried out to validate the practical feasibility.     

轨道交通集中告警系统的集成设计

目前,在国内包括北京、上海、广州、深圳、南京、成都等各大城市,轨道交通综合监控系统项目的建设正在快速地增长,轨道交通通信专业的集中告警系统是其必须集成的一个子系统,可对其集成的方法却缺乏统一的标准和规范。给出了轨道交通集中系统的接口集成设计的一种十分可行的方法,目前,该方法已经在北京地铁五号线、南京地铁二号线中得以应用。简要地介绍了目前轨道交通综合监控系统的概况,给出了轨道交通综合监控系统与集中告警TEL／ALM系统的接口设计方案,并根据实际需求,提出了综合监控系统与集中告警TEL／ALM系统的接口软件实现流程。     

A sensor-driven approach to Web-based machining

The objective of this research is to develop a framework named Wise-ShopFloor and the enabling technologies for collaborative manufacturing in a decentralized environment. Particularly, this paper presents our latest development on Web-based and sensor-driven remote machining. Once a product design is given, its process plan and NC codes are generated by using a distributed process planning (DPP) system. The NC codes are then used for remote machining via a standard Web browser and a Java GUI interface running inside the browser. In this paper, the focus is given to the concept, architecture and a prototype implementation of the enabling technology. A case study of a test part machining on a 5-axis milling machine is also completed for testing and validation. It is expected that the developed technology can be applied to design verification via remote machining as well as real part production in a distributed manufacturing environment.     

基于T-S模型的网络控制系统故障诊断

针对一类参数不确定并具有时延和丢包情况的非线性网络控制系统,为达到快速准确的进行故障诊断的目的,提出了一种基于T-S模糊模型的故障诊断方法.通过建立此系统的T-S模糊模型,利用平行分布补偿时延的思想设计了满足系统稳定性条件的状态反馈控制器,以及通过引入随机切换系统表示数据有无丢失情况下的基于模糊观测器的鲁棒故障诊断方法,然后基于 Lyapunov函数和线性矩阵不等式方法给出了该闭环网络控制系统渐近稳定的充分条件,最后通过仿真例子验证了该方法能够使闭环控制系统渐进稳定以及能够准确的进行故障诊断,验证了所设计方法的有效性.     

双向中继系统中断概率下界优化及分集增益

主要研究了瑞利衰落信道下基于放大转发策略的双向中继系统的中断性能及分集性能。首先利用信源节点信噪比间的关系和调和不等式对信噪比的范围进行优化,得到新的中断概率下界,仿真结果表明Monte Carlo仿真得到的中断概率接近新得到的中断概率下界;同时证明了多中继存在时,基于最大最小互信息准则的双向中继系统仍然取得全分集增益且能够优化中断概率下界。     

层析成像技术在网络属性估算中的应用研究

网络层析成像技术在网络属性估算中的应用主要分为网络拓扑判定和链路属性估算两个重要应用.主要讨论通过对网络上的主机进行单播的测量来获得网络的逻辑拓扑及链路属性,并提出进行网络属性估算的新方案.首先介绍基于延时的"三明治"测量方案和相关网络拓扑判定算法,随后通过实验对网络拓扑判定的系统聚类树算法进行了分析,在此基础上提出进行网络属性估算的新方案.     

动态不确定非线性系统直接自适应模糊backstepping控制

对一类单输入单输出动态不确定非线性系统,提出一种直接自适应模糊backstepping和小增益相结合的控制方法.设计中,首先用模糊逻辑系统逼近虚拟控制器:其次把自适应模糊控制和backstepping控制设计技术相结合.给出了直接自适应模糊控制设计方法.最后基于Lyapunov函数和小增益方法证明了整个闭环系统的稳定性.仿真实例进一步验证了所提方法的有效性.     

基于Virtools的虚拟小区漫游系统的设计与实现

虚拟建筑小区漫游系统是虚拟现实技术的综合应用,作者使用三维建模软件-3DMAX软件和多功能三维开发工具软件-Virtooh软件,设计实现了南堡盐场西苑小区虚拟漫游系统.此系统可以为用户提供多视点、多场景的浏览,使人有身临其境之感.