解扩解调技术应用研究和新近展

对解扩解调和技术实现的发展状况作了比较全面的回顾。分类介绍了传统的解扩解调及其改进技术,并分析了这些解扩解调技术的优缺点,最后简要阐述了新出现的解扩解调技术。     

校园网内WEB服务器容错及负载平衡的实现

利用Windows 2000中的DNS服务器组件,实现校园网内部的WEB服务器容错和平衡负载的功能。     

Out-of-Bounds Array Access Fault Model and Automatic Testing Method Study

Out-of-bounds array access(OOB) is one of the fault models commonly employed in the objectoriented programming language. At present, the technology of code insertion and optimization is widely used in the world to detect and fix this kind of fault. Although this method can examine some of the faults in OOB programs, it cannot test programs thoroughly, neither to find the faults correctly. The way of code insertion makes the test procedures so inefficient that the test becomes costly and time-consuming. This paper, uses a kind of special static test technology to realize the fault detection in OOB programs. We first establish the fault models in OOB program, and then develop an automatic test tool to detect the faults. Some experiments have exercised and the results show that the method proposed in the paper is efficient and feasible in practical applications.     

多异构电信信息集成系统中的动态数据同构与同步技术

多异构电信信息集成系统涉及到多个不同结构的信息系统数据库之间的数据交换.为了保证数据的一致性,往往需要在某一子系统数据更新时进行动态数据复制,将该子系统数据库的新增数据及时同步到异构集成系统的数据库中.针对这一问题,提出了基于.NET面向对象的数据库编程技术,以实现数据库同构;用Oracle透明网关和SQL Server连接服务器实现异构数据库的同步解决方案.     

一种新的用于WCDMA基站布局规划的移动台分配方法

提出了一种新的用于WCDMA基站布局规划的移动台分配方法,在基站布局规划的上、下行链路计算中基于链路发射功率与小区负载进行移动台分配.通过一组基站布局规划实例,将该移动台分配方法与当前WCDMA基站布局规划中常用的基于链路衰减的移动台分配方法进行了比较.实验结果表明,所提出的移动台分配方法可以在基站布局规划中对移动台进行更为合理的分配,减少业务分布不均匀时规划结果中选择的基站数目.     

Fitness Landscape Analysis for Optimum Multiuser Detection Problem

Optimum multiuser detection （OMD） for CDMA systems is an NP-complete combinatorial optimization problem. Fitness landscape has been proven to be very useful for understanding the behavior of combinatorial optimization algorithms and can help in predicting their performance. This paper analyzes the statistic properties of the fitness landscape of the OMD problem by performing autocorrelation analysis, fitness distance correlation test and epistasis measure. The analysis results explain why some random search algorithms are effective methods for OMD problem and give hints how to design more efficient randomized search heuristic algorithms for OMD.     

Urban Railway Accessibility

Effective use of urban rapid railway systems requires that the railway systems be effectively con-nected with other transportation modes so that they are accessible. This paper uses the logit model and data to analyze the factors influencing railway access choices in a railway choice access model. The results indicate that access time, access cost, and access distance are factors significantly affecting railway access choices. The user’s income significantly affects the probability of choosing to walk rather than to take a taxi, but is not related to choosing buses or bicycles. Vehicle ownership significantly affects the probability of choosing a taxi, but is not significantly related to the other modes. The conclusions provide an analysis tool for urban railway planning and construction.     

基于Internet的代理缓存技术的研究

讨论基于Internet的代理缓存的目标、性质和工作原理,从而论述了代理缓存技术成为解决Web访问速度慢、服务器负载重和网络阻塞等问题的主流技术的原因.最后,指出基于Internet的代理缓存技术仍存在的一些问题和研究前沿.     

基于现场总线的OPC接口技术的研究

在对OPC技术及其数据访问规范研究的基础上，分析了OPC的对象与接口模型，给出了基于OPC自动化接口的OPC同步数据访问应用程序的设计，对OPC技术的应用前景进行了展望。     

VPN技术框架研究

讨论了用户对VPN的普遍需求、隧道技术机制对构建VPN的重要作用，以及为提供VPN的通用安全业务，隧道机制应该满足的功能和性能基本要求，按VPN的构建原理讨论了VPN的分类。