SSH匿名流量网站指纹攻击方法

SSH匿名通信系统是保护信息安全和用户隐私的一种有效手段,但SSH匿名通信也有可能被用于网络犯罪活动,针对SSH匿名通信被滥用难以监管的问题,提出一种基于一维卷积神经网络的SSH匿名流量网站指纹攻击方法。该方法将特征工程与预测分类步骤整合,避免了传统指纹攻击方法中的特征提取、选择与组合的手工过程,将下行网络流按字节转换为相应数值并归一化,然后使用深度一维卷积神经网络提取高维流量指纹特征并预测分类,通过实验对100个网站目标进行指纹攻击,准确率达到92.03%,表明该方法能够对SSH匿名通信进行有效指纹攻击。     

基于深度神经网络burst特征分析的网站指纹攻击方法

以Tor为代表的匿名网络是一种隐匿用户数据传输行为的通信中介网络.不法分子利用匿名网络从事网络犯罪,对网络监管造成了极大的困难.网站指纹攻击技术是破解匿名通信的可行技术,可用于发现基于匿名网络秘密访问敏感网站的内网用户行为,是网络监管的重要手段.神经网络在网站指纹攻击技术上的应用突破了传统方法的性能瓶颈,但现有的研究未充分考虑根据突发流量(burst)特征等Tor流量特征对神经网络结构进行设计,存在网络过于复杂和分析模块冗余导致特征提取和分析不彻底、运行缓慢等问题.在对Tor流量特征进行研究和分析的基础上,设计了轻便的基于一维卷积网络的burst特征提取和分析模块,提出了基于深度神经网络分析burst特征的网站指纹攻击方法.进一步,针对在开放世界场景中仅使用阈值法简单分析指纹向量的不足,设计了基于随机森林算法的指纹向量分析模型.改进后的模型分类准确率达到了99.87%,在缓解概念漂移、绕过网站指纹攻击防御机制、识别Tor隐藏网站、小样本训练模型和运行速度等方面均有优异的性能表现,提高了网站指纹攻击技术应用到真实网络的可实践性.     

基于图像纹理的网站指纹技术

网站指纹技术能够让本地监听者通过审查用户与Tor入口节点之间的匿名流量从而追踪到该用户访问的具体网站。现有的研究方法只提取了匿名流量中的部分元数据来进行网站指纹的刻画，忽视了大量隐含的指纹信息。为此，提出了基于图像纹理和深度卷积神经网络的网站指纹技术Image-FP。首先，将匿名通信流量映射成RGB彩色图；然后，使用残差神经网络(ResNet)构造出能进行自主特征学习的网站指纹分类模型。在50个网站构成的封闭世界场景下，Image-FP能够取得97.2%的分类准确率，相较于最前沿的网站指纹攻击技术提高了0.4个百分点。而在更接近真实环境的开放世界场景中，Image-FP能够以100%的准确率识别出监控网站的流量，其准确性和鲁棒性更是远远高于其他指纹技术。实验结果表明，匿名流量图像化的技术能够更多地保留网站指纹的相关特征，并且在避免复杂特征工程的同时，能够进一步提高分类精度。     

基于ARF的Tor网站指纹识别技术

不法分子通过Tor等匿名通信系统构建暗网隐匿其不法行为,给网络监管带来了严峻挑战.网站指纹识别技术能根据加密流量来推测用户访问的站点,是一种有效的监管手段.已有的网站指纹识别技术采用的多为基于批处理的静态模型,无法有效解决概念漂移问题.针对Tor网站指纹,文章提出一种基于自适应随机森林(ARF)算法的动态网站指纹识别模...     

基于.NET的Web安全机制

默认情况下大多数Web站点都允许匿名访问,任何用户通过Internet连接都可以进入该站点并查看其中的页面,用户无须身份验证便可以访问站点上的任何文件.但是,对于大多数Web站点来说,并不是所有的页面都让人匿名访问,Web安全就是为限制只有特定用户群才可以访问某些文件而设计的.     

基于Web行为轨迹的应用层DDoS攻击防御模型

为了有效防御应用层分布式拒绝服务攻击（DDoS）,定义了一种搭建在Web应用服务器上的基于Web行为轨迹的防御模型。把用户的访问行为抽象为Web行为轨迹,根据攻击请求的生成方式与用户访问Web页面的行为特征,定义了四种异常因素,分别为访问依赖异常、行为速率异常、轨迹重复异常、轨迹偏离异常。采用行为轨迹化简算法简化行为轨迹的计算,然后计算用户正常访问网站时和攻击访问时产生的异常因素的偏离值,来检测针对Web网站的分布式拒绝服务攻击,在检测出某用户产生攻击请求时,防御模型禁止该用户访问来防御DDoS。实验采用真实数据当作训练集,在模拟不同种类攻击请求下,防御模型短时间识别出攻击并且采取防御机制抵制。实验结果表明,Web行为轨迹的防御模型能够有效防御针对Web网站的分布式拒绝服务攻击。     

站点指纹模型训练系统FMTS的设计与实现

基于指纹识别的匿名攻击原型系统用于度量攻击的复杂程度,定量评估匿名Web浏览系统的匿名性,提供实验平台。作为其重要组成部分,站点指纹模型训练系统(FingerprintModelTrainingSystem,FMTS)用于遍历目标站点的网页,抽取页面指纹及链接关系构造形成站点指纹模型。文中介绍了指纹模型训练系统的总体设计方案以及关键实现技术。并针对系统的一个实际运行结果———中南大学网站(www.csu.edu.cn)的指纹模型,分析了其“指纹”分布情况。     

基于Web日志挖掘的信息无障碍网站设计研究

针对当前一些实现信息无障碍网站存在的问题,该文设计了一个网站设计架构,利用Web日志挖掘技术提取用户兴趣和访问优先序列,采取网站页面信息动态填充至网站主页通用框架模块中,实现智能化、个性化无障碍访问。     

网络用户浏览行为的分析

近年来,Web使用挖掘成为数据挖掘领域中一个新的研究热点,Web使用挖掘是从记录了大量网络用户行为信息的Web日志中发现用户访问行为特征和潜在规律.本文结合某高校主页的真实运行数据,通过Web使用挖掘对于网站的运行日志文件进行全面的挖掘分析,分析用户对信息内容的兴趣度,并通过用户对网页的访问数据推算出各个页面受众的兴趣度高低,借此改良网站的内容和布局.     

基于非对称资源消耗的应用层攻击方法

通过网络爬虫技术分析目标Web网站页面信息,提取其中消耗Web服务器资源较大网页的URL特征,并据此生成攻击URL集;利用正常用户访问行为训练得到访问行为模型参数,根据参数模拟用户访问,并实现攻击总强度弱、但单次攻击请求即能引起目标服务器较大资源消耗的攻击。实验结果显示了该方法的可行性。     

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.