浅析ARP欺骗原理及解决方法

在局域网中,通信前必须通过ARP协议来完成IP地址与第二层物理地址（即MAC地址）的转换。由于ARP协议存在安全漏洞,使得ARP欺骗相应产生。从一个实例解析ARP欺骗的原理和其解决方案。     

数字移动通信接入信令分析

阐述了数字移动通信的关键技术——接入信令。对接入信令的格式、传输协议和传输方式等进行了具体分析。     

Providing Public Access to the Shore: The Role of Coastal Zone Management Programs

In many coastal states and territories, coastal zone management (CZM) programs have been the prime catalyst in leveraging public access initiatives among state and federal agencies, public organizations, and the private sector. A wide range of tools are used, including acquisition, regulations, technical assistance, and public education. The diversity of approaches is illustrated through a variety of case examples. Although hard numbers for measuring outcomes were not uniformly available, between 1985 and 1988, when federal and state CZM funding dedicated to public access was tracked, $141.5 million (unadjusted 1988 dollars) were spent on 455 public access-related projects. A policy shift occurred in the 1990s away from reliance on acquisition and regulation as the most effective means of providing access and toward technical assistance and public outreach-a response to the overall decrease in funds available for access. CZM programs have been able to balance the contradictory goals of the federal Coastal Zone Management Act of 1972 (CZMA), such as protecting coastal resources while providing for increased public access to those resources. It is recommended that CZM programs conduct assessments to determine the kind of access needed in the future and where it should be located. And, due to the creativity and innovation that states and territory coastal programs use to achieve access, it is recommended that a national clearinghouse be established for documenting and sharing information on innovative tools and programs.     

Sensitive analysis of emission rates in MOVES for developing site-specific emission database

With the rapid social and economic development, vehicle emissions have been identified as a major source of urban air pollutions in China. Therefore, the study on vehicle emission estimations is necessary. In light of the limitation of emission data for establishing a local comprehensive emission database, this paper analyzes the characteristics of emission rates in MOVES released by U.S. Environmental Protection Agency (EPA) to investigate the feasibility and to design a method for developing site-specific emission database. Sensitive analysis for model year, age group and speed interval is performed, and the regularity is concluded. The result shows that emission rates are almost constant with model year, but increase with age groups because of emission deterioration. With respect to speed intervals, the emission rates in 25–50 mph are higher than both those <25 mph and >50 mph in the same VSP (vehicle specific power) bins. In addition, an analysis of local emission data in Beijing is conducted to build the relationship between vehicle activities and emission rates. After that, a comparison of emission rates by VSP bins in MOVES and in local database is conducted in this study. The result shows that the absolute values are different because of regulatory emission standards, fuel quality, and other factors. However, the relative changes described by normalizing emission rates have a good consistency. Hence, the regularities of emission rates by VSP bins in MOVES can be used to develop local emission database in Beijing.     

LabVIEW在主机遥控系统中的应用

介绍基于LabVIEW的主机遥控系统的实现方法;通过基于MODBUS协议的网络将主机遥控系统的车令、报警等信息存储到监控系统数据库,通过访问数据库查看主机遥控系统的操作、报警信息,取代传统的车钟记录仪及报警信息存储单元,同时也可以进行远距离查询,提高了机舱自动化的水平。     

Foxpro菜单生成系统分析与应用

本文研究了Foxpro的菜单生成系统。首先讨论了菜单定义文件的结构、字段的含义，然后分拜了菜单生成器的处理流程、各函数和过程的作用，最后给出了一些应用。     

一种大型结构试验数据处理系统

以土木工程结构实验及结构现场检测系统为原型，抽象出数据库模型，用以存放实验或检测中所有获取的原始数据．根据处理数据的工序流程，定制了基于MATLAB软件的前端数据库管理程序，并结合MATLAB的强大科学计算功能，方便地实现了对实验数据的管理、查询、处理及可视化表现功能．     

通过OCI封装类实现数据库的快速访问

基于Oracle海量数据库的大型应用开发对系统响应时间提出了越来越高的要求,如何有效地提高Oracle数据库的访问效率,减少系统等待时间成为一个研究热点。介绍一种数据库访问方法OCI（Oracle Call Interface）,并通过分析和对比ODBC、JDBC和Pro＊C/C＋＋的实现原理,表明OCI在访问Oracle数据库上性能优越性。通过C＋＋类封装OCI,可实现多平台应用系统快速访问Oracle数据库。该类（接口）不仅克服了直接使用OCI过于复杂、不可重用等缺点,同时具有效率高,代码可读性、易维护性和可重用性增强等优点。     

计算机编制列车运行图分布式数据库系统规划与设计

基于对客户机／服务器分布式处理形式的分析,采用结构化设计和分布工ＰｏｗｅｒＢｕｉｌｄｅｒ程序设计的方法,在计算机编制列车运行图２．１版的基础上,对计算机编制列车运行图数据库系统的网络进行了规划与设计,为计算机编制列车运行图的研究拓展了新的空间。     

铁路客运信息查询算法

铁路客运信息查询算法是建立在数据库基础上的.为用户提供全国范围内任意两个车站之间合理的乘车方案,该算法需要建立的数据库包括:车次表、车站表、时刻表和相关局表,通过这些基本数据库,使用中转算法可以产生中转站表,从而构成铁路客运信息查询算法的基础.当用户任意给定两个车站时,查询算法能在短时间内给出合理的乘车路线、乘车车次、乘车时间以及中转位置等信息,用户可以利用这些信息指导自己的铁路旅行.