网页文本分类中的特征选择研究

由于超链接语言结构本身所提供的信息,网页分类问题不同于一般的文本分类。本文分析了网页内部特征,并在1000篇网页规模语料库的基础上,通过试验对比了三种特征选择方法对高维特征向量空间进行降维的效果。文章还提出了一种新方法,根据特征项所处的位置赋予不同权重的方法,实验表明这种由文本结构导出的权重计算方法能够取得很好的分类效果。     

网格及网格体系结构的研究

介绍了网格的基本概念、特点和功能分类,阐述了一种重要的网格体系结构——五层沙漏结构,同时对网格技术在国内外的发展现状作了分析。     

基于集群系统的导弹流场并行数值模拟

采用36颗安腾2处理器和Infiniband网络设备构建了一套18节点的高性能计算集群系统,经过性能调优,其Linpack值达到每秒可执行1 886亿次浮点运算(188.6 GFlops)的水平.然后,将集群系统扩展为适用于计算流体力学并行应用的数值模拟平台.建立了约为783万结构化网格的战术导弹三维流场仿真模型,通过网格分区算法将模型移植到集群系统上并行求解,并测试了集群系统的性能.结果表明,构建的CFD数值模拟平台硬、软件资源配置合理,能够适用于中等规模的CFD并行仿真.     

应用移动代理技术实现矩阵的并行计算

本文结合移动代理技术给出了一种矩阵并行计算的算法及其在Aglet移动平台中的实现。     

Grid GIS and its application in digital city

Digital city is a synthetic project in which large geographic and trade data are involved in, thus data sharing becomes a key problem. Grid GIS is an outcome of integrating GIS and network techniques, it has a lot of characteristic of network technique such as heterogeneous, extensible, dynamic autoadaptable, the multistage management, etc. The advantages of parallel processing of grid computing are obvious when it is used in basic data platform construction of digital city. The architecture and core techniques of Grid GIS which suitable for constructing basic data platform of digital city was discussed, it has some guidance effects to the city information building.      

Security Architecture of Trusted Virtual Machine Monitor for Trusted Computing

With analysis of limitations Trusted Computing Group （TCG） has encountered, we argued that virtual machine monitor （VMM） is the appropriate architecture for implementing TCG specification. Putting together the VMM architecture, TCG hardware and application-oriented ＂thin＂ virtual machine （VM）, Trusted VMM-based security architecture is present in this paper with the character of reduced and distributed trusted computing base （TCB）. It provides isolation and integrity guarantees based on which general security requirements can be satisfied.     

A Method to Implement Full Anonymous Attestation for Trusted Computing Platform

Trusted computing （TC） technology is brought out by trusted computing group （TCG） to make computing as safe and reliable as people expect. Attestation is one main function specified by TCG, which is the means by which a trusted computer assures a remote computer whose platform is not tampered with. There are two protocols that implement attestation without disclosing the platform＇s real identity, which are Privacy CA-based protocol and direct anonymous attestation （DAA） protocol. However, in the first protocol the privacy CA is the bottleneck and the platform＇s identity will be disclosed if the privacy CA is compromise, while DAA protocol can do profiling when dealing with rogue hardware device. In this paper, we propose a DAA-extended new approach to ensure full anonymous attestation that can not only detect a rogue TPM, but also reveal rogue TPM＇s real identity.     

支持移动IP的无线接入点研究与设计

分析了现行无线局域网的不足和应采取的相应对策，给出了支持移动IP的无线局域网基本体系结构。研究了支持移动IP的无线接入点的扩展功能和协议栈，提出了新的子层－IP关口层。分析无线接入点在IP关口层和数据链路层对移动IP的支持，并给出了支持移动IP的无线接入点软件设计方案。     

移动网络环境中的平滑切换与TCP优化

对移动网络环境中的平滑切换和TCP优化进行了研究.介绍了平滑切换的有关概念，分析了平滑切换的实现方法，指出了现有TCP协议应用于无线移动通信的不足之处，为进一步提高移动计算的服务质量，提出了一种新的无线TCP优化策略.     

基于仿真的铁路旅客列车提速潜力分析

介绍了我国铁路近年来在提高旅客列车运行速度中的措施,提出了旅客列车运行过程中采用目标速度策略对其进行控制的思路及算法.通过对该策略的详细分析,从列车牵引计算的角度出发,利用作者开发的计算机仿真系统,对京广线旅客列车再提速的可行性进行了具体研究,得出当前条件下京广线部分区段内旅客列车存在一定的提速空间的结论.