基于变换域的纹理防伪标签自动鉴别算法

研究纹理防伪标签自动识别问题,由于纹理防伪标签人眼鉴别比较困难、耗时较长,不能实现自动鉴别的问题,提出一种基于变换域的纹理防伪标签自动鉴别算法,用于实现纹理防伪标签的自动鉴别,可自动鉴别标签真伪.首先对纹理防伪标签图像进行DWT和DFT,在变换域中提取一个视觉特征向量,并存入数据库,最后通过特征向量之间的归一化相关系数来鉴别.如何提取一个抗几何攻击的特征向量是算法的难点.实验结果表明,改进方法可以有效抵抗几何攻击,可实现纹理防伪标签的自动鉴别.与现有的纹理防伪技术相比,改进算法可减小占据的数据库存储空间,缩小鉴别时间,有更好的灵活性和实用性.     

一种基于DCT和NCG的数字视频水印算法

随着计算机和网络技术的快速发展,数字水印技术正成为一种数字媒体知识产权保护的有效手段.提出一种基于DCT和NCG的数字视频水印算法.它根据NCG,对视频帧进行分类,选择具有复杂纹理特性的帧,进行分块DCT,然后比较DCT后的一对中频系数而嵌入水印.仿真实验表明,该算法具有较好的透明性,能实现水印盲检测,可抵抗常见的视频处理及攻击,如压缩、滤波、添加噪声、裁剪等.     

基于Watson视觉感知模型的能量调制水印算法

提出一种具有大容量、低复杂性的鲁棒水印算法,主要适合于(但不局限于)JPEG图像和MPEG视频流的实时水印嵌入与检测,因为该算法直接运行于DCT(discrete cosine transform)块数据上.算法主要通过在感知范围内修改DCT块的中低频系数来调制块能量.在能量调制过程中,利用Watson视觉感知模型推导出一条准则,用于限制DCT系数的修改幅度.该系统具有较大的水印容量,可实现在512×512图像中嵌入2 048比特.实验表明,算法不仅具有较好的透明性,而且对一些常见的攻击(如高斯噪声、低通滤波、JPEG压缩、增减亮度等)和部分几何攻击(如线性偏移、剪切等)具有较好的鲁棒性.     

抗裁剪和平移攻击的图像拷贝检测算法

有效判定经拷贝攻击之后图像的版权归属是当今图像拷贝检测研究的热点和难点之一.现有的检测算法对于噪声、拉伸、旋转、等比缩放等常见攻击具有较好的鲁棒性,而对于裁剪、平移攻击则比较脆弱.针对上述问题,提出一种基于SIFT局部特征和整体DCT系数顺序测度的图像拷贝检测算法.该算法首先通过匹配的SIFT特征划定内容保持不变的区域,然后对内容不变区域的亮度分量作整体DCT变换,并将DCT系数低频交流成分的顺序测度作为图像特征,最后通过该特征判定拷贝是否存在.由于匹配的SIFT特征可以精确定位拷贝发生区域,因而对裁剪、平移攻击具有较好的抵抗能力,又由于引入整体DCT系数顺序测度作为特征,因而可以很好地抵抗其他常见攻击.同时提出翻转补偿策略,使本算法能抵抗水平翻转和垂直翻转攻击.实验结果证明,在抵抗裁剪和平移攻击方面,给出的算法相对于已有算法具有较高的查准率和查全率.     

基于混沌特征的运动模式分割和动态纹理分类

采用混沌理论对动态纹理中的像素值序列建模,提取动态纹理中的像素值序列的相关特征量,将视频用特征向量矩阵表示. 通过均值漂移（Mean shift）算法对矩阵中的特征向量聚类,实现对视频中的运动模式分割. 然后,采用地球移动距离（Earth mover’s distance,EMD）度量不同视频的差异,对动态纹理视频分类. 本文对多个数据库测试表明:1）分割算法可以分割出视频中不同的运动模式;2）提出的特征向量可以很好地描述动态纹理系统;3）分类算法可以对动态纹理视频分类,且对视频中噪声干扰具有一定的鲁棒性.     

基于FPGA的防伪阅读器

分析现有防伪技术的缺陷,结合射频识别和信息安全理论,提出符合国际标准的RFID防伪阅读器,讨论应用于防伪系统的防伪认证机制和加密算法,在此基础上实现基于现场可编程门阵列的防伪阅读器的原型系统。该原型系统集成了标签防伪的加密算法、阅读器身份防伪的认证算法以及IP核技术,有效实现了商品真伪的鉴别。     

抗局部攻击的最优块提取水印算法

基于提高水印算法鲁棒性的目的,在分块DCT变换的基础上,利用水印图像各DCT块像素之间的相关性,提出了一种提取最优块的数字水印算法,同时采用Watson的感知水印模型,满足了水印算法不可感知性的要求.试验结果证明算法对抗局部攻击极为有效,几乎可以实现水印的完全提取,抗全局攻击能力也有一定的提高.试验验证采用了Stirmark 4.0水印基准测试软件,保证了试验的真实性和准确性.     

基于DCT与DWT的音频水印算法

采用DCT和DWT两种方法相结合的抗同步攻击的鲁棒性数字音频水印算法,利用DWT的多分辨率特性以及DCT的解相关能力和聚能作用,并且在音频分段后引入同步技术,在保证不可感知性和稳健性的良好平衡下实现了水印的盲检测。使用纠错码技术进行水印的嵌入,以此来降低水印的检测错误率。在接收端进行盲提取。实验结果表明,该算法具有很强的鲁棒性和不可感知性。     

一种基于DWT抗几何攻击数字水印鲁棒算法

针对大部分数字水印算法抗几何攻击能力差这一难题,提出了一种基于小波变换可抗击几何攻击算法.在水印嵌入部分:首先对宿主图像进行小波分解、嵌入水印,再通过余弦变换求得该水印图像的一个特征向量,利用该特征向量和水印信息通过HASH函数生成一个二值逻辑系列,将该序列作为密钥;水印提取部分为:对待测的图像进行小波变换,再通过余弦变换求得待测图像的一个特征向量,利用该特征向量和密钥通过HASH函数提取出水印.文章最后对水印图像进行了旋转、缩放和扭曲等几何攻击试验.试验表明,该算法有理想的抗几何攻击能力.旋转攻击的旋转角度可达40°,缩放攻击的缩放比例可达0.2,旋转扭曲攻击的扭曲角度可达100°.     

基于分块DCT变换的抗旋转,缩放攻击零水印算法

大多数基于DCT、变换域的零水印算法没有抵抗几何攻击的能力,例如将图像旋转微小角度即可导致水印检测的失败.为了提高基于DCT变换域的零水印算法抵抗图像抗旋转,缩放攻击的能力,本文提出了一种基于分块DCT变换的抗旋转,缩放攻击零水印算法.对于旋转,缩放造成的几何攻击,我们可以通过对数极坐标系将笛卡尔坐标系中的旋转,缩放变换转换为循环平移的性质,对于循环平移后的图像,在水印检测时我们可以使用穷举遍历的方法来检测测试图像是否包含水印信息.实验结果证明,该方法可以获得良好的图象视觉效果,同时对于加噪,滤波,JPEG压缩,剪切攻击也具有有很好的鲁棒性.     

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。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

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.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

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.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

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。