云计算环境下用户行为安全认证机制的研究

云计算环境中用户对云数据的安全负有重大责任.用户行为安全认证是确保云服务系统安全运行的有效技术途径,借助安全认证技术可以及时发现用户非法操作、恶意攻击行为或潜在的安全漏洞.对现有用户安全认证机制进行了深入研究,分析安全认证机制的类别和各种认证技术的特点,提出云计算环境中应用安全认证机制中存在的问题.     

基于硬件虚拟化的内核同层多域隔离模型

为了解决内核不可信带来的问题,很多工作提出了同层可信基的架构,即在内核同一硬件特权水平构建可部署安全机制的唯一保护域.但是,实际过程中往往面临多样化的安全需求,将多种对应的安全机制集中于唯一的保护域必然导致只要其中任何一个安全机制被攻陷,同一个保护域内其它所有安全机制都可能被攻击者恶意篡改或者破坏.为了解决上述问题,本文提出了内核同层多域隔离模型,即在内核同一硬件特权水平构建多个保护域实现了不同安全机制的内部隔离,缓解了传统方法将所有安全机制绑定在唯一保护域带来的安全风险.本文实现了内核同层多域隔离模型的原型系统Decentralized-KPD,其利用硬件虚拟化技术和地址重映射技术,将不同安全机制部署在与内核同一特权水平的多个保护域中,并不会引起较大的性能开销.总体而言,实验结果展示了内核同层多域隔离模型的安全性和实用性.     

Android应用能耗漏洞分析技术综述

随着移动互联网技术的迅速发展,Android手机以其强大的功能为人们的日常生活提供便捷的服务。然而Android手机的电池能源非常有限,应用耗电行为将直接影响其电池的使用寿命,因此Android应用的能耗漏洞问题受到研究者的广泛关注。研究者们已经提出并实现了很多分析技术和相关工具。针对Android应用能耗漏洞分析,对相关研究方法和工具作了综述,概括了现有研究工作中的问题,讨论了未来研究方向。     

基于SVM的Android应用程序安全检测综述

当前基于SVM的Android应用程序安全检测技术主要是通过将SVM算法与动静态分析方法相结合,应用于Android应用程序的漏洞和恶意软件的检测中,而恶意软件的检测又可分为恶意行为的检测和恶意代码的检测。故本文按SVM算法应用到的检测领域分类,分别对其应用于Android应用程序中的恶意行为检测、恶意代码检测和漏洞检测方面的研究进行分析与讨论,并总结了当前该领域中仍然存在的一些问题,给出了SVM算法和其应用于Android安全检测中的改进之处,最后对未来的发展进行了展望。     

基于硬件虚拟化的内核同层多域隔离模型

为了解决内核不可信带来的问题,很多工作提出了同层可信基的架构,即,在内核同一硬件特权水平构建可部署安全机制的唯一保护域.但是,实际过程中往往面临多样化的安全需求,将多种对应的安全机制集中于唯一的保护域必然导致只要其中任何一个安全机制被攻陷,同一个保护域内其他所有安全机制都可能被攻击者恶意篡改或者破坏.为了解决上述问题,...     

基于Toast重复绘制机制的口令攻击技术

移动终端在飞速发展的同时也带来了安全问题,其中,口令是用户信息的第一道安全防线,因此针对用户口令的窃取攻击是主要的安全威胁之一.利用Android系统中Toast机制设计的缺陷,实现了一种基于Toast重复绘制机制的新型口令攻击.通过分析Android Toast机制的实现原理和功能特点,发现恶意应用可利用Java反射技术定制可获取用户点击事件的Toast钓鱼键盘.虽然Toast会自动定时消亡,但是由于Toast淡入淡出动画效果的设计缺陷,恶意应用可优化Toast绘制策略,通过重复绘制Toast钓鱼键盘使其长时间驻留并覆盖于系统键盘之上,从而实现对用户屏幕输入的隐蔽劫持.最后,攻击者可以通过分析用户点击在Toast钓鱼键盘上的坐标信息,结合实际键盘布局推测出用户输入的口令.在移动终端上实现该攻击并进行了用户实验,验证了该攻击的有效性、准确性和隐蔽性,结果表明:当口令长度为8时,攻击成功率为89%.发现的口令漏洞已在Android最新版本中得到修复.     

基于Android虚拟化框架的隐私保护方案

Android插件，是在Android系统中一个全新的应用级虚拟化技术。这种虚拟化技术已经广泛应用于热门应用的开发，因为宿主系统对于宿主系统中的被多开的应用具有不弱于Root权限的权限，能够方便地、快捷有效地介入应用的运行过程，也能够实时动态检测宿主系统中应用的运行状况。应用级虚拟化框架的引入，打破了Android原有的安全机制，引入了一定威胁，例如特权提升攻击、代码注入攻击、勒索软件攻击、系统服务漏洞和网络钓鱼攻击，恶意应用软件可以利用虚拟化框架的漏洞进行隐私数据的获取。因此，本文针对以上漏洞在虚拟化框架中进行修复，通过本文中的方案，提供了一个比较安全可靠的虚拟化框架供应用在其中运行，并且不会对Android原生系统进行修改，保证用户的隐私数据能够免受恶意APP的窃取。     

浏览器WEB安全威胁检测技术研究与实现

WEB浏览器是一种常见的客户端应用程序,是用户与网络交互的最主要平台之一,WEB应用已经广泛应用到新闻资讯、电子商务、社交网络等多个领域,然而由于WEB应用程序功能性和交互性的不断增强,对应的WEB漏洞和恶意攻击层出不穷,现有的WEB安全措施主要集中于服务端,然而客户端的安全机制相对比较薄弱,因此,对于如何保证WEB应用的安全己成为安全界广泛关注的重点。本文主要研究浏览器端的WEB安全威胁检测技术与实现。     

Android平台数据安全保密机制探析

Android操作系统数据安全是为数据处理系统建立技术和管理安全保护,保护用户的数据不因偶然和恶意的原因而遭到破坏、更改和泄漏。为了更好地保护Android手机用户的信息安全,可以通过动态安全口令认证、SQLite数据库安全设计机制、使用密钥将明文转化成密文等方式来实现。     

针对安卓手机提权漏洞的新型防范模型设计与验证

目前,智能手机安全问题引起了人们高度的重视。木马作为一种隐蔽性、欺骗性很高的攻击手段,在该平台上不断蔓延,虽然受到广泛关注,但却没有很好的防范手段。在各种漏洞中,提权漏洞对于Android系统的安全威胁巨大,一旦攻击者有机会获得内核的内存地址,就能够通过关闭内核内存的写保护获得向内核内存写入恶意指令的权限,并实现下载木马病毒的目的。为应对这一漏洞,首先分析SEAndroid机制,并基于此机制提出一种新型的将内核加强和数据包过滤2种方法结合的提权漏洞防范模块,并通过实验对所提出的防范模块的有效性进行验证。     

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.