基于图像纹理复杂度的小波域数字水印算法

针对水印信息嵌入量小、鲁棒性弱、遮蔽性差的问题,提出一种基于图像纹理复杂度的小波域人类视觉系统的水印算法。该算法将载体图像进行分块,计算每块的图像熵,并根据图像熵对载体图像的纹理特征区域进行分类,不同纹理特征水印的嵌入量不同。利用Logistic映射对水印信号进行置乱变换,将水印信号嵌入到二层离散小波变换的低频系数中,并利用小波域人类视觉模型控制水印的嵌入强度。在提取水印时,通过水印误码率和峰值信噪比评价水印质量。实验结果表明,该算法能抵抗噪声干扰、裁剪和密钥攻击,水印图像具有较强的鲁棒性和良好的遮蔽性。     

基于纹理特征定位的数字图像水印算法

提出一种基于图像纹理特征锁定水印嵌入位置的水印算法。利用Canny算子在非采样Contourlet变换最高阶方向子带内筛选图像的纹理特征,将强纹理特征的位置作为水印嵌入的索引点。对非采样Contourlet变换的低频子带进行一级小波分解,在小波细节子带上分割N个圆环(N为水印信息长度)区域,根据索引位置在每个圆环区域内自适应地重复嵌入水印。仿真实验表明,该算法不仅具有较好的透明性,而且对图像处理和几何攻击均具有较好的鲁棒性。     

基于IWT和广义差值扩展的可逆水印算法

针对传统差值扩展可逆水印算法的缺陷,提出了一种基于整数小波变换（IWT）和广义差值扩展的可逆水印算法。它将原始图像划分成4×4大小的互不重叠的像素块;计算各分块的近似平滑度值,该值在水印嵌入前后保持不变;将所有分块按平滑度值进行排序;根据水印信息量,依序选取适当数目的分块;对所选取分块进行整数小波变换,在变换后的低频部分利用广义差值扩展法嵌入水印信息,在高频部分通过数据压缩嵌入水印辅助信息。实验结果表明,该算法在减小图像失真的同时,提高了信息嵌入量,另外在同等水印嵌入量下,该算法的[PNSR]高于常见的一些算法。     

提升方案小波和HVS下的自适应视频水印算法研究

提出一种基于小波域与HVS特性的自适应视频水印盲提取算法.算法首先将视频流分割成一个个镜头,并通过密钥从中选取嵌入水印信息的若干镜头,镜头中的视频帧图像与灰度水印图像均被变换到小波域中,并将水印图像的小波域系数按照小波树结构重新进行分块并按位平面重要次序形成水印序列;水印的嵌入是按照子带到子带的顺序进行的,水印序列被嵌入到视频帧图像相应子带的重要系数中;此外,水印的嵌入充分考虑了HVS对图像纹理区域、运动区域的掩蔽特性,使得水印的嵌入强度具有自适应性,从而保证了所嵌入水印在不可见性前提下的极大鲁棒性.试验结果表明,所给出的算法对于诸如Gaussian噪声、丢帧、帧平均和MPEG-4压缩等常见攻击具有很好的鲁棒性.     

小波变换域均值调制的可读图像盲水印算法

提出了一种小波变换域均值调制的可读图像盲水印算法,利用图像经离散小波变换后细各细节子带系数均值近似为零的特点,根据细节子带系数的局部方差,自适应地修改图像小波分解后某些细节分量的局部均值,在满足水印不可感知性的条件下自适应地嵌入水印信息,实现水印不可感知性和鲁棒性之间的折衷。同时,在不借助原图像的前提下,实现水印的盲检测。水印信息是一幅有实际意义的二值图像。实验结果和攻击测试表明,提出的算法对常见的滤波、JPEG压缩、添加噪声、剪切等多种攻击有较强的鲁棒性。     

一种基于HVS的小波域抗JPEG压缩水印算法

提出一种小波域的用于图像内容认证的水印算法。该算法提取图像特征作为认证水印信息,利用分块图像的临界噪声阈值(JND)自适应的调整分块图像的细节子带小波系数大小关系来嵌入水印信息,从而提高了水印的透明性。实验结果表明该算法具有很好的抗JPEG压缩性能和篡改定位功能。     

一种小波域自适应数字水印算法

本文提出了一种基于连续子带量化(SSQ)和人类视觉系统(HVS)的小波域自适应数字水印算法。该算法中,水印嵌入到图像的视觉重要系数(PSCs)上,PSCs是从小波变换后低频子带和高频子带中选出来的。其中,低频子带中的PSCs是根据系数的幅值来选出的,高频子带中的PSCs是通过子带量化选出。为了更好的嵌入水印,该算法中利用了HVS模型,(?)模型基于噪声可见性函数(NVF)的计算来决定水印嵌入强度,使水印更多的嵌入到图像的纹理和边缘区域。     

一种改进的基于离散余弦变换的数字水印算法

以离散余弦变换(DCT)为基础,针对产品版权保护问题提出了一种改进的数字水印算法.其基本思想是根据宿主图像的特征,在不同区域分别嵌入可见水印和不可见水印,用canny算子对宿主图像进行边缘检测,并结合纹理和亮度特征,将可见水印图像分块嵌入宿主图像中.嵌入不可见水印时,首先对二值不可见水印图像进行混沌序列加密等预处理,再根据对宿主图像离散余弦变换(DCT)的结果,自适应地进行嵌入.实验结果表明,本算法生成的含水印图像既可保持宿主图像的质量,又能使可见水印细节可见.此外,不可见水印对宿主图像影响较小并具有较好的鲁棒性.     

具有人类视觉特性的可见水印算法

论文提出一种基于小波变换的可见水印算法,该算法利用人类视觉模型的亮度CSF和纹理敏感特性,根据主图像和水印图像的局部和全局特征,建立确定水印嵌入的拉伸系数数学模型。首先描述了人类视觉及小波分解系数分析,给出了小波系数视觉重要性权重值。把原图像和水印图像小波系数频率子带分成不同的块,基于视觉掩模对子块进行分类。利用人眼的纹理敏感特性,进一步增强了嵌入水印的图像视觉质量。仿真实验表明该算法结果良好。     

基于LWT-SVD的鲁棒自适应水印方案

为进一步提高水印抵抗攻击的能力,提出一种基于量化的混合提升小波变换和奇异值分解的自适应数字图像水印算法。对二值水印信号进行异或加密与置乱处理,以增强水印信号的安全性和鲁棒性;对原始载体图像进行互不重叠的分块,对随机选取的分块进行一级提升小波变换,对生成的低频子带进行奇异值分解;根据水印信号的取值,对每一分块低频子带的最大奇异值采用自适应量化的方法嵌入水印信号。仿真结果表明,该算法具有较好的透明性和抵抗常规信号处理攻击的能力。     

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.