查询词典 introduced

In this paper, the concept of network security and security structures of OSI and Internet is introduced, and various threats confronting the computer network are also discussed. Several kinds of network information security technologies, including firewall technology, virtual private network, intrusion detection system, data encryption technology, identity authentication and security protocol etc. are also examined. The security of internal network is the biggest problem in the construction of each network. The solution to this problem lies in setting up a firewall. The theory of a firewall and the approach to its actualization is studied. Intrusion detection system, an important part of the computer network security system, has gained extensive attention. IDS monitors the computer and network traffic for intrusion and suspicious activities. It not only detects the intrusion from the extranet hacker, but also the intranet users. The emergence of virtual private network paves the way for realizing secure connection of LAN quickly and at a relatively low cost. The concept, function, key techniques, including the tunnel technology, and the ways to realize VPN are expounded in this paper. Also introduced is the data encrypt network technology, which is called the soul of computer network security, such as digital digest, digital signature, digital certificate, digital encrypt arithmetic and so on. At the same time, the principle and the process of implementing network security by digital certificate and digital signature, the basic principle and characters of security protocols, and finally, three of the security protocols, concerning the security problems in network, IPsec, SLL and SET are analyzed in detail Computer network system should be a system of dynamic defence, both dynamic and static, passive as well as active, and even offensive, combined with management and technology.

本文系统地介绍了网络安全的概念、OSI及Internet的安全体系结构，并讨论了计算机网络面临的各种安全威胁；内部网络的安全问题是每个建网单位面临的最大问题，可以认为防火墙技术是解决网络安全的一个主要手段，本文研究了防火墙的原理及其实现手段；作为一种主动的防御措施，入侵检测系统作为网络系统安全的重要组成部分，得到了广泛的重视，TDS对计算机和网络资源上的恶意使用行为进行识别和响应，不仅检测来自外部的入侵行为，也监督内部用户的未授权活动；虚拟专用网技术的出现，为实现网络间的连接提供了快速安全但又相对便宜的手段，本文较深入的探讨了实现VPN的隧道技术，并对VPN的概念、功能、实现途径、基本构成、关键技术及发展前景等问题进行了全面论述；数据加密技术是网络安全核心技术之一，本文从数据加密算法、数字摘要、数字签名及数字证书等几方面简要介绍了数据加密技术，并分析用数字证书和数字签名实现网络安全的原理和过程；对安全协议的基本原理、主要特点进行了较为深入的研究，并就网络的安全性问题剖析了三种安全协议：IPsec协议、SLL协议和SET协议。

In this paper, a carrier frequency synchronization algorithm based on autocorrelation has been introduced and realized in FPGA firstly, especially the Cordic algorithm and its realization. Secondly, two symbol synchronization algorithm based on crosscorrelation and autocorrelation are introduced and implemented in FPGA, then the comparison between them is made in the view of realization. Besides, the methods of area diplex and pipelining are embodied in implementation scheme of FPGA.

本文首先介绍了一种基于自相关的载波频率同步算法，给出了它的FPGA实现方案，重点讲述了其中用到的Cordic算法及其实现；然后介绍了分别基于互相关和自相关的两种符号同步算法，给出了各自的FPGA实现方案，从实现的角度比较了两种算法的优缺点，并且在FPGA设计中体现了面积复用和流水线操作的设计思想。

Following such study clue, I gradually introduced the factors that should be taken into account in discretionary disclosure and integrated all the theories in a frame. Firstly, I introduced the concept of "proprietary cost" and analyzed the level and strategies of disclosure which were taken by firms.

本文按照逐步引入影响因素的方法将现有的理论串成一线：首先引入"专有性成本"这一因素，分析了专有性成本理论框架下公司选择性披露水平及决策问题；在此基础上，引入了产品市场竞争因素，分析了不同产品市场竞争环境下公司的选择性披露决策；接着，笔者又将金融市场竞争因素引入，解释了为什么上市公司事实上并非完全遵循产品市场竞争环境下的披露策略，而会出现披露的"羊群行为"。

In this paper, a new medical impedance imaging modality (Magnetic resonance electrical impedance tomography-MREIT) is first introduced, including its mathematical theories and the reconstruction algorithms. Then its application in early breast cancer detection research is introduced in detail. Finally, its future research direction and major problems are summarized.

本文在此前提下介绍了一种高分辨率的医学电阻抗成像技术－磁共振电阻抗成像技术的成像原理与成像算法，然后介绍了MREIT技术在早期乳腺癌检测方向的应用，最后分析了该研究方向的发展前景以及目前存在的问题。

In chapter 2, basic knowledge of the rough set theory, such as indiscernibilityrelation, elementary set, approximate space, upper approximation, lower approximation, negative region, boundary region, rough set, etc., and algebraic properties of rough set are introduced. At the same time, the feature of the rough, set theory is also introduced.

第二章介绍了粗糙集理论基本知识，如不可分辨关系、基本集、近似空间、上近似、下近似、负域、边界域、粗糙集等概念，以及粗糙集的代数性质，同时还介绍了粗糙集理论的特点。

In this paper,the Elmo Servo motion control system made in Israel based on CAN bus is introduced.Each part of the system and its modules are introduced in detail.

本文介绍了运用以色列Elmo伺服及其CAN总线技术实现的交流伺服运动控制系统，具体设计了整个控制系统的各个部分及其内部模块。

This article introduced a test principle and emendation technology of automatic test system of motorcycle governor fork are introduced.

介绍了目前摩托车换档拨叉自动检测系统的测试原理及其校正技术，探讨了该校正技术在应用中存在的一些问题。

This article introduced a test principle and emendation technology of automatic test system of motorcycle governor fork are introduced. Some of the problems existed in practice are explored.

介绍了目前摩托车换档拨叉自动检测系统的测试原理及其校正技术，探讨了该校正技术在应用中存在的一些问题。

Some common used channel codes are introduced, and emphasis is placed on linear block codes, cyclic codes, BCH codes, RS codes, convolutional codes and the promising turbo codes, which is planned to be implemented in the third locomotive communication systems. Their performance is analysed and compared. And some method to reduce errancy is submitted, also the interleaved technique is introduced.

文章介绍了几种常用的信道编译码方案，如线性分组码，循环码，BCH码，RS码，卷积码等，分析和比较了它们的性能，并对第三代移动通信系统的选用码Turbo码作了简要介绍，对提高纠错性能提出了若干改进方案，同时介绍了交织技术减少差错的作用。

In view of situation that existing controller and networking communication of low-voltage breaker adopt user-defined protocol, which has shortcomings of poor reliability and exchangeability in communication, the paper introduced a design scheme of a new type of intelligent controller for low-voltage breaker based on DeviceNet protocol and introduced its design of hardware and software in details.

针对现有低压断路器控制器与控制网络通信因采用自定义协议而存在通信可靠性低和互换性差的缺点，介绍了一种基于DeviceNet协议的新型低压断路器智能控制器的设计方案，详细介绍了控制器软、硬件设计。

If you are unfortunate enough to the lovelorn, please tell me, I will help you out, really, please contact me!

如果你不幸失恋了，请告诉我，我会帮助你摆脱困境，真的，请联系我啦！

China's plan to cut energy intensity by 20 percent and pollutant discharges by 10 percent between 2006 and 2010 is a case in point.

中国计划在2006年到2010间降低20%的能源强度和减少10%的主要污染物排放，就是一个这样的例子。