数字网络体系结构

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。

It includes four parts: 1 Part I, it introduces the basic knowledge of computer viruses such as computer virus definition, history and important viruses events, features, behavior phenomena, difference with computer software and hardware troubles, damage behavior and capability, classification, naming, future trend, etc; 2 Part II, it introduces the corresponding knowledge of computer systems related to computer viruses such as the composing of software and hardware of the computer system, storage media and its working mechanism, interrupt technologies,.com/.exe/.pe file formats and their working mechanism, etc; 3 Part III, it introduces computer virus mechanism and theory such as computer virus structure, work flow, working mechanism of key modules, typical technologies used to design computer viruses including the corresponding traditional technologies (interrupt filching, memory resident, etc.), the corresponding new routine technologies (self-encrypting, Mutation Engine, etc.), and the corresponding new technologies used by some prevalence computer viruses such as macro viruses, e-mail viruses, worm, hacker, Trojan, mobile phone viruses, the working mechanism analysis of some kinds of typical and prevalence computer viruses such as file-type viruses, macro viruses, e-mail viruses, worm viruses, hacker, Trojan, mobile phone viruses, the analysis of some typical and prevalence computer viruses examples including BALL viruses, WORD macro viruses, WantJob viruses, Code Red viruses, BO Trojan, etc; 4 Part IV, it introduces the defense and killing technologies of computer viruses such as the aim and criterion of computer viruses defense and killing, prevention methods and corresponding technologies, detection technologies (comparison method, character code scanning method, behavior inspecting method, analysis method, etc.), manual and automatic killing technologies, immunity technologies such as IBM digital immunity system, new anti-viruses technology trends (real-time anti-viruses technologies, 32 kernel technologies, active kernel technologies, etc.), some typical virus defense and killing softwares (Symantec AntiVirus product, PC-Cillin AntiVirus product, etc.), the defense and killing method analysis of some kinds of typical and prevalence computer viruses (file-type viruses, macro viruses, worm viruses, hacker, etc.), for example, firewall and intrusion detection technologies for anti-hacker, the defense and killing of some typical and prevalence computer viruses examples including WORD macro viruses, Code Red viruses, BO Trojan, etc.

课程内容具体包括四大部分：1）第一部分，介绍计算机病毒基本知识，包括：计算机病毒定义、病毒发展史及重大事件、病毒特点、病毒表现现象及与软硬件故障的区别、病毒破坏行为及危害性、病毒的传播途径及媒介、病毒分类、病毒的命名及计算机病毒技术发展趋势等内容；2）第二部分，介绍与计算机病毒有关的计算机系统相关知识，包括：计算机系统软硬件组成、存储介质结构及工作原理、计算机系统引导机理及流程、中断技术、。com/。exe/。pe等文件格式及工作机理等内容；3）第三部分，讲解计算机病毒机理，包括：计算机病毒的组成结构、病毒工作流程、病毒引导/触发/感染/破坏等模块的工作机理、计算机病毒所采取的编制技术（包括中断窃取/内存驻留等传统编制技术、自加密/隐形/变形机等新的常规编制技术、宏病毒/电子邮件病毒/网络蠕虫/特洛伊木马/黑客/手机病毒等一些新的流行病毒所采取的编制技术等）、一些类型的典型或流行计算机病毒的工作机理分析（包括：引导型病毒、文件型病毒、宏病毒、电子邮件病毒、蠕虫病毒、黑客、特洛伊木马、手机病毒等）、一些典型或流行的计算机病毒实例剖析（包括：小球病毒、WORD宏病毒、求职信病毒、红色代码病毒、冰河木马等）等内容；4）第四部分，讲解计算机病毒防治技术，包括：计算机病毒防治目的、病毒防治策略及规范、病毒在管理和技术上的预防措施、病毒检查技术（包括：比较法/病毒特征码扫描法/行为监测法/虚拟执行法/分析法等）、手工和自动病毒清杀技术、病毒免疫技术（包括：针对某种一次性感染病毒的基于病毒标签的免疫方法/基于自我完整性检查的计算机病毒免疫方法/IBM的数字免疫系统等）、反病毒技术的新发展（包括：实时反病毒技术/32位内核技术/主动内核技术/以毒攻毒技术等）、诺顿/趋势/金山等公司的病毒防治软件产品、一些类型的典型或流行的计算机病毒（包括：引导型病毒、文件型病毒、宏病毒、蠕虫病毒、电子邮件病毒、手机病毒、黑客、特洛伊木马）的防治措施（其中，也包括介绍面向防范黑客攻击的防火墙、入侵检测技术）、一些典型或流行的计算机病毒防治实例剖析（包括：WORD宏病毒、红色代码病毒、冰河木马v1.1/v2.2等）、多层次病毒防护体系等内容。

The main contents of the thesis include: the requirements analysis of neural computation to neurochip; the architecture of digital general-purpose neurochip; the design and implementation of neurochip hardware; the architectures of neurocomputer that can be built out of the neurochip; the neural network mapping algorithms; the user integrated developing environment with friendly interface; and the study of algorithms for neural network models.

本文的主要研究内容有：神经计算对神经芯片的需求分析；通用数字神经芯片体系结构；芯片硬件的设计与实现；基于神经芯片的神经机系统结构；神经网络映射算法；友好的用户开发环境；神经网络算法，等等。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。