基于支持向量方法和击键序列的主机入侵检测

击键特征是一种能反映用户行为的动态特征,可作为识别用户的信息源。传统方法不仅要求收集大量击键样本来建立识别模型,并且同时需要正例样本与反例样本。但在实际应用中,需要用户提供大量的训练样本是不现实的,并且反例样本收集比正例样本收集困难。为此,提出一种新的以击键序列为信息源的主机入侵检测模型。在小样本和仅有正例的情况下,通过One-Class支持向量机（OCSVM）来训练检测模型,通过对用户的击键行为是否偏离正常模型来检测入侵。仿真实验结果表明该模型具有较好的检测效果。     

基于支持向量数据描述的击键生物特征认证

由于计算机用户对键盘的熟悉程度、击键习惯等不尽相同,每个用户都具有自己独特的击键生物特征,对于某个用户来说,其击键特征为正常类,其他所有用户为异常类,这可以利用模式识别中的单类分类器来解决,本文设计基于支持向量数据描述(SVDD)的击键生物特征身份认证系统模型,将该方法与BP、RBF和SOM方法进行对比,证实SVDD具有较好的识别效果,它可将非法用户误接受率从28.9%降低到0.28%,最后给出一个嵌入Windows用户登录中的口令+击键特征身份认证的实现技术.     

基于键盘行为数据的用户身份识别

用户击键行为作为一种生物特征,具有采集成本低、安全性高的特点。然而,现有的研究方法和实验环境都是基于实验室数据,并不适用于极度不平衡的真实数据。比如,在实验室数据上效果出色的分类算法在真实数据上却无法应用。针对此问题,提出了基于真实击键行为数据的用户识别算法。该方法将聚类算法和距离算法结合起来,通过比较新来的击键行为和历史击键行为相似度以实现用户识别。实验结果表明,该算法在100名用户的3015条真实击键记录组成的数据集上准确率达到88.22%,在投入实际应用后,随着样本集的增大算法的准确率还可以进一步提升。     

基于分析Unix命令击键特征检测系统冒用

提出了一种检测入侵者冒充其他用户对系统进行操作的方法。统计表明，每个人在进行键盘录入时，其击键特点与其他人互不相同，通过分析当前用户Unix命令的击键特征与其历史击键特征比较，判定两者是否相符，以此检测当前用户是否是合法用户。实验结果显示，这种方法能比较好地鉴别假冒用户。     

基于击键特征的用户身份校验

基于用户所特有的击键节奏特征,提出了一种判别某一击键序列是否为某特定用户的行为的方案.该方案利用非参数方法中的Spearman相关分析来确定计算cityblock距离所需的权值,进而利用预存样本与新输入样本之间的距离来判定用户的身份.所以此方案不受各种可能击键的概率分布限制.一个基于击键特征的用户身份校验系统已经使用Java语言成功地实现.     

基于击键压力和时间匹配的异常检测方法

为了有效利用用户的生物特征进行入侵者身份识别,提出了一种基于用户击键特征进行异常检测的新方法.该方法根据人们在击键时所产生的按键压力和时间间隔的惟一性,利用正态分布的特性控制模式库生成方式,构造出能够描述每个用户独有特征的击键特征向量库,然后利用模式匹配算法对新登陆用户进行检测.相关实验验证了该方法具有较高的用户识别能力.     

解决Windows 7不能玩《穿越火线》的方法

腾讯启动游戏时会添加一个驱动(比如腾讯的Tenprotect),但有时Windows 7系统会因为兼容性会认为安装的这个驱动不稳定,会自动阻止该驱动安装,让用户无法正常玩游戏。     

基于实时击键序列的主机入侵检测

基于主机的入侵检测是保障计算机网络信息安全的重要手段之一．该文在介绍击键特性及其识别算法的基础上,根据大量试验结果,确定将具体键的击键序列作为信息源,提出了一种改进的贝叶斯统计方法,实现了主机入侵检测．该方法既能独立于用户名和口令之外对用户进行身份认证,又能动态监控用户击键的整个过程,文中对系统实现的关键问题和检测结果进行了详细的分析和讨论．     

基于键盘行为进行用户识别的方法与应用

基于键盘行为的已有研究大多限制在实验环境下,并限定用户的输入为特定字符串,或只在有限实验参与者中进行识别,从而导致其无法应用在真实的环境中。为了克服已有研究的局限,解决真实环境中正负样本不均衡和负样本缺失的问题,对真实环境下一千万条用户击键行为进行分析,提出了一种基于键盘行为进行用户识别的方法。该方法使用击键持续时间和击键间隔时间描述用户的击键行为,通过实验选择马氏距离进行用户击键行为相似度的对比,并对未知击键行为进行预测。实验结果表明,该方法可获得80%的预测准确率。     

基于差别子空间的用户击键特征识别

根据用户的击键行为特征，提出了一种基于差别子空间的识别算法，该算法仅依据用户前几次成功登录的击键特征计算出能够代表用户击键的共性特征向量，进而利用当前用户击键特征向量与共性特征向量的欧几里德距离作为判别依据来判定用户的身份。该算法主要进行内积运算，实现简单且识别速度快，实验结果表明该算法误报率较低，鲁棒性较强。     

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.