网络入侵检测系统NIDS的Snort工具的研究

随着互联网的迅速普及,其安全技术的重要性已经日益突出,IDS(IntrusionDetectionSystem)是网络安全技术的重要组成部分之一。NIDS是基于审计的IDS,通过被动地分析网络的流通信息包括数据包的报头和数据信息以达到检测网络异常行为的发生。Snort是一个基于libpcap的数据包嗅探器并可以作为一个轻量级的网络入侵检测系统(NIDS)。本论文通过介绍NIDS中Snort工具的检测规则、功能结构、程序结构以及与其它NIDS工具的比较,讨论了Snort的不足之处,并对其的改进提出了一些建议性的思路,以期能在进一步的研究中起到抛砖引玉的作用。     

利用Netfilter实现NIDS集群的研究和实践

目前基于网络的入侵检测系统(NIDS)面临普通单机检测设备的数据包处理能力不能适应网络带宽发展需求的问题，该文介绍了利用NIDS集群在高速网络环境下实现入侵检测的方法。根据NIDS集群的特点利用Linux内核中Netfilter模块实现了数据包基于分流转发和会话的动态负载均衡。并通过使用基于Linux操作系统的IDS负载均衡器实现了NIDS集群在高速网络环境下的入侵检测。     

基于Snort的边界数据包安全性检测

无论是蠕虫病毒、木马或是其他的网络攻击行为,无不向目标网络发送恶意数据包,以达到恶意攻击的目的.网络监控成为检测来自外部网络的数据包安全性的重要手段,Snort作为防火墙的补充广泛应用于网络内部,监控网络流量、数据包安全等.将Snort IDS部署在网络边界,基于CVE漏洞库建立本地Snort特征库,以检测所有通过边界的数据包,保护内网安全.     

基于Netfilter框架的分布式网络入侵检测系统

针对网络入侵检测系统（NIDS）的处理速度无法跟上网络通讯及其数量的增长速度,提出了基于Netfilter的分布式NIDS系统和负载均衡算法,在Netfilter上实现了数据包的分流,使得分配到每一个NIDS的数据包的集合是一个特定攻击的特征集合。实验表明,分布式NIDS中每个NIDS的负载基本相等,漏检率减少到了单个NIDS的1/4。     

基于GPU的高速网络入侵检测系统设计

随着网络带宽的不断增加,以及处理能力的限制,传统的网络入侵检测系统（Network Intrusion Detecting System,NIDS）面临挑战,如何提高NIDS的处理能力备受关注。通过专用设备提高检测速度,不但价格昂贵且无法大规模普及。通过对Linux网络协议栈的优化,以及常用入侵检测系统Snort的多线程化,结合了图形处理器（Graphic Processing Unit,GPU）的高性能并行计算能力,设计了一种高性能的软件入侵检测架构,突破现有NIDS使用普通CPU的计算瓶颈,以应对高速链路对入侵检测性能的要求。实验结果表明,高速网络中的数据包可以采用GPU来处理。     

一种入侵检测系统的规则描述语言

入侵检测系统(IDS)是保护信息系统安全的重要方式。而新一代IDS的一个最主要的特点就是IDS入侵检测规则描述语言。该文通过对Snort规则的分析与比较，提出了一种基于网络的IDS规则描述语言，它具有直观易定义、描述精确等特点。     

Snort中规则匹配机制的改进

Snort是一个基于libpcap的数据包嗅探器并可作为一个轻量级的网络入侵检测系统,它属于误用检测。该文通过介绍Snort的基本原理,系统结构,规则分析,匹配机制等,讨论了其在规则匹配机制方面的不足,并提出了一些改进的意见和方法,来提高Snort规则匹配的速度,从而提高Snort的整体性能。     

用于网络入侵检测的模式匹配新方法

针对新一代网络入侵检测系统(NIDS)的创建需要先进的模式匹配引擎,提出一种模式匹配的新方案,利用基于硬件的可编程状态机技术(B-FSM)来实现确定性处理过程。该技术可以在一个输入流中同时获取大量模式,并高效地映射成转换规则。通过对网络入侵检测系统中普遍采用的规则集(Snort)进行实验,实验结果表明该方法具有存储高效、执行速度快、动态可更新等特点,可以满足NIDS的需要。     

HIDS渐成主流

当前的网络IDS系统可以分为基于网络数据包分析的系统(NIDS)和基于主机分析的系统(HIDS)两种基本方式。简单地讲,HIDS产品主要对主机的网络实时连接以及系统审计日志进行智能分析和判断,在宿主系统审计日志文件中寻找攻击特征,然后给出统计分析报告;NIDS产品在网络通信中寻找符合网络入侵模板的数据包,并立即作出相应反应。     

Linux下小型网络入侵防御系统的设计与实现

针对目前小型网络的安全防御问题,在Linux环境下利用开源firewall—iptables和IDS—Snort设计了一种IDS告警的融合、过滤机制,实现了IDS和防火墙的智能化联动,并且利用PHP提供了一个远程管理工具．通过将入侵检测技术、防火墙技术和PHP技术三者融合在一起．本文构建出一种适用于小型网络的入侵防御系统．     

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.