网络分析

Mobile agent has been an important means of managing distributed systems. With mobile agent, the traffic between PDP and network device is dramatically reduced. It analyzes the advantages and disadvantages of mobile agent based network management and policy-based network management, proposed architecture of network management with flexibility, intelligence and autoimmunization, and discussed the performance, to evaluate the feasibility of the architecture.

移动代理已经在分布式管理中得到应用，采用移动代理可大大减少策略决策点和网络设备之间的通信流量，通过对基于移动代理的网络管理和基于策略的网络管理的分析研究，结合两种技术的优点，提出了一种具有良好的适应性的自动化网络管理体系结构，并进行性能分析。

Moreover, with its help people can also evaluate the fault-tolerant performance of ANN. In this paper, Chebyshev Inequality method, as a kind of evaluating thought, was firstly concerned in the faulttolerance analysis of ANN; 4. The variation of faulty behaviors of ANNs during the course of learning was studied by taking the discrete Hopfield neural network and Hebb learning algorithm as examples.

这种方法首次将切比雪夫不等式引入人工神经网络容错性分析当中，从而提出了对人工神经网络容错性分析采用估算的思想； 4 以离散型Hopfield神经网络和Hebb学习算法为例，着重研究了在学习过程中人工神经网络故障性能的变化。

The research of this paper is began with the analysis the geographic spatial character of the UPTN, and designs the UPTN data mode based on GIS. Then, based on the good exhibiting all kinds of topology of the UPTN, and combined with the technology evaluation standards of the UPTN, this paper builds the UPTN planning mathematic model, and puts forward the quantitative calculation of the UPTN evaluation standards based on GIS; brings forward the arithmetic of the optimal path of the UPTN based on the public traffic network storage structure; designs the bus lines grouping management model, and realizes the contradistinctive evaluation of the UPTN planning projects based on GIS.

论文研究的重点内容是从分析城市公交网络中地理空间实体的特征开始，设计基于GIS的城市公交网络数据模型，在有效表现公交网络拓扑关系的基础上，根据公交线网技术评价指标，建立基于GIS的公交线网规划的数学模型，并给出公交线网评价指标的GIS量化计算方法；提出以公交线网数据存储结构为基础的公交网络最优路径算法；设计公交线路分组管理模型，实现公交线网规划方案对比分析。

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。

The thesis introduces the concept and evolution of NC at first, and analyzes the difference of between NC and PC, diskless workstation, and discusses emphatically the characteristics and applications of NC network architecture, then introduces the definition, the mission and the function area of network management, analyzes a few architecture of network management, and goes deep in to study Simple Network Management Protocol.

论文首先介绍了NC的概念及其发展过程，分析了NC与PC、无盘工作站的区别，重点讨论了NC网络体系结构的特点和应用。然后介绍了网络管理的定义、任务和功能域，分析了现有的几种网络管理的体系结构，并深入研究了简单网络管理协议。

For two examples, result testifies that it is feasible to use in nonlinear restriction optimization. Chapter 3 is important part in the paper. Analyze and research BP network, concealed node number of network former frame newly. Give new supplement and advice about How to select study velocity and activation function in BP algorithm.

第3章是论文中最重要的一章，通过实例分析研究了BP网络，对网络模型结构的隐层节点数进行分析和新的探讨；对BP算法中的学习速率和激活函数的选取进行了新的补充和建议；对网络的拓扑结构进行了新的构造；对人工神经网络收敛依据提出了新的判断原则。

We do research on the transitions between states of network protocol,the protocol misusage detection model based on Markov chain,the framework of the IDS technology and protocol anormity after we discuss the current technology. The main research contents of this paper include: research on transitions between states of network protocol and session process, protocol misuage and the anomaly detection model based on Markov chain, the research of intrusion detection framework, more accurately model based on the characteristic of the network traffic and so on.

在分析了现有入侵检测系统的基础上，本文围绕典型网络协议状态转换、基于马尔可夫链的检测模型、入侵检测技术框架、以及协议异常等几个方面展开深入研究，主要工作内容包括：典型网络协议转换状态的分析和会话过程的研究；基于马尔可夫链的网络异常检测模型；分布式的检测架构；针对网络流量特征而提出了精确的检测模型等。

The research is comprised mainly of four aspects: bounds of network reliability; performability of network reliability; lumpability problems of network reliability models; fuzzy analysis methods of network reliability.

研究内容主要包括四个部分：网络可靠性界的计算、网络综合可靠性分析方法的研究、马尔可夫型可修网络系统中聚合问题的研究以及网络的模糊可靠性分析方法的研究。

The dissertation includes the work as follows: Firstly, we present a random graph model with spatial reuse for a dense MANET which using directional antennas. The analytic formula of several important performance parameters for the MANET are obtained under the DSR routing protocol, such as the average flooding distance, the probability generating function of the flooding distance, the probability of a flooding route to be symmetrically valid, the average time to find a symmetrically valid route and the cost to successfully route a data packet to its destination. We compare the two models with spatial reuse and without spatial reuse by evaluating these parameters. It is shown that the spatial reuse model is much more effcctive in terms of the performance of the dense network with directional antenna, because the bigger is the degree of spatial reuse, the smaller is the average flooding distance.

在定向天线技术的支持下，建立了移动自组网络空间可重用的贝努利随机图模型，获得了DSR路由协议下平均泛洪距离的解析公式和泛洪距离的概率母函数：给出了有效对称路由概率、发现有效路由平均时间、成功路由代价等关键性能参数的解析分析；在网络性能参数定量分析的基础上，对空间可重用和无重用的网络进行了比较分析，结果显示空间重用度增大，则平均泛洪距离、路由发现时延、网络代价减少。

And we also succeed in inosculating the technic of multithreading、 multiple buffers、 windows socket、 IP multicast and RTP real time transmission by using Visual C++6.0 and MS Directshow SDK, and obtained a good result. At the same time, we carried on researching the robustness of this software. We made the research findings of digital video transmission based on network used in applications of banks, and got very good social effects and economic benefit.

本文主要在以下方面做了深入的工作： 1、结合数字视频监控应用的需求分析，对研究网络视频传输技术的意义做了阐述和分析，并就如何充分利用现有网络资源和成熟的多媒体计算机技术进行视频监控等领域的具体应用做了有益的探索； 2、对&数字视频的网络传输&应用中所涉及到的关键技术进行了深入的分析、比较，并进行了有机的融合。

And Pharaoh spoke to Joseph, saying, Your father and your brothers have come to you.

47：5 法老对约瑟说，你父亲和你弟兄们到你这里来了。

Additionally, the approximate flattening of surface strip using lines linking midpoints on perpendicular lines between geodesic curves and the unconditional extreme value method are discussed.

提出了用测地线方程、曲面上两点间短程线来计算膜结构曲面测地线的方法，同时，采用测地线间垂线的中点连线和用无约束极值法进行空间条状曲面近似展开的分析。