基于NetFlow的蠕虫病毒监控系统设计与实现

NetFlow是Cisco公司在其交换、路由体系中采用的一种三层交换技术。NetFlow服务能够提供包括地址、协议、端口和服务类型等详细的数据流统计信息。由于蠕虫病毒传播过程中会发起大量的扫描连接,使用Flow-tools等工具统计分析NetFlow数据流,可以很容易地找出染毒计算机IP地址,再利用SNMP准确地定位该IP的位置并关闭其所连交换机端口,就可以将染毒计算机与网络隔离。同时对染毒计算机相关信息的详细记录,为网络管理员对染毒计算机的处理提供了准确的信息。     

基于NetFlow的网络异常流量检测

NetFlow可以提供网络中IP流的信息。这些流的信息有多种用途，包括网管、网络规划、ISP计费等。在网络安全领域，NetFlow提供的IP流信息可以用来分析网络中的异常流量，这是对现有的基于特征的NIDS的很好的补充。本文介绍了Net—Flow—based Anomaly Traffic Analyzer，一个基于NetFlow的网络异常流量检测系统，并通过一些实验证明了该系统的有效性。     

IP地址全力大搜查

与好友在网络上相互传输资料时，有时先要知道对方计算机的IP地址，才能与对方建立信息传输通道；那么对方的IP地址该如何搜查得到呢?这样的问题你也许会嗤之以鼻，的确，查询对方计算机的IP地址，实在简单得不值得一提；可是，要让你列举出多种IP地址搜查方法时，你可能就感到勉为其难了。下面，本文就对如何快速、准确地搜查出对方好友的计算机IP地址。提出如下几种方法，相信能对大家有所帮助!     

基于NAT的混合型防火墙

传统防火墙分析 包过滤防火墙位于协议网络层,按照网络安全策略对IP包进行选择,允许或拒绝特定的报文通过。过滤一般是基于一个IP分组的有关域(IP源地址、IP目的地址、TCP/UDP源端口或服务类型和TCP/UDP目的端口或服务类型)进行的。基于IP源/目的地址的过滤,即根据特定组织机构的网络安全策略,过滤掉具有特定IP地址的分组,从而保护内部网络;基于TCP/UDP源/目的端口的过滤,因为端口号区分了不同的服务类型或连接类型(如SMTP使用端口25,Telnet使用端口23等),所以为包过滤提供了更大的灵活性。同时由于它是位于协议的网络层,所以效率较高;但是该防火墙所依靠的安全参数仅为IP报头的地址和端口信息,若要增加安全     

IP地址的管理及绑定技术的应用

阐述了局域网地址使用中的常见问题,详细描述了TCP/IP协议的工作原理,提供了管理IP地址的两种方案:静态地址协议解析ARP表绑定和交换机端口绑定,并对方案做了详细的阐述,给出了具体的配置方法,为有效地管理局域网的IP地址提供了实用的参考方案.     

基于端口隔离静态IP地址冲突防范策略

校园网络中不可避免会出现IP地址冲突.通过分析ARP协议,提出基于VLAN端口隔离利用二层协议重定向策略和DHCP RELAY安全绑定建立一种高效静态IP和MAC管理策略.解决在VLAN和接入交换比较多情况下IP-MAC绑定的繁杂重复工作,避免启用DHCP SERVER不能准确定位接入主机IP地址缺点.经过实验和实际应用实现了静态IP地址冲突防范.     

ARP欺骗/MITM攻击在二层交换机上的防范

本文主要针对目前非常典型的二层攻击和欺骗说明如何在思科交换机上组合运用和部署Dynamic ARP Inspection(DAI)技术,从而实现防止在交换环境中实施"中间人"攻击、地址欺骗等,更具意义的是通过Dynamic ARP Inspection(DAI)技术的部署可以简化地址管理,直接跟踪用户IP和对应的交换机端口;防止IP地址冲突。同时对于大多数对二层网络造成很大危害的具有地址扫描、欺骗等特征的病毒可以有效的报警和隔离。     

查找对方IP地址经典技巧汇总

与好友在网络上相互传输资料时,有时先要知道对方计算机的IP地址,才能与对方建立信息传输通道。那么对方的IP地址该如何搜查得到呢?这样的问题你也许会嗤之以鼻,的确,查询对方计算机的IP地址,实在简单得不值得一提;可是,要让你列举出多种IP地址搜查方法时,你可能就感到勉为其难了。下面,本文就对如何快速、准确地搜查出对方好友的计算机IP地址,提出如下几种方法,相信能对大家有所帮助!     

IP地址全力大搜查

与好友在网络上相互传输资料时,有时先要知道对方计算机的IP地址,才能与对方建立信息传输通道;那么对方的IP地址该如何搜查得到呢?这样的问题你也许会嗤之以鼻,的确,查询对方计算机的IP地址,实在简单得不值得一提;可是,要让你列举出多种IP地址搜查方法时,你可能就感到勉为其难了。下面,本文就对如何快速、准确地搜查出对方好友的计算机IP地址,提出如下几种方法,相信能对大家有所帮助!     

快速搭建Linux防火墙

Windows中可以通过IP安全策略,来对进出本机的网络数据包进行过滤,进而可以自由控制指定端口的开合状态,这实际上起到了简易的包过滤防火墙的作用,因为IP数据包具有一定的特性,例如其包含源地址、目标地址、源端口和目标端口、协议号等属性。     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.