DCT频域选块分组多重数字盲水印嵌入算法

对宿主图像频域进行二维DCT变换,采用灰度图像JND门限值和多数字基底对宿主图像的DCT频域构造了选块分组技术,对中频分量的DCT交流系数分组嵌入水印比特,对高低频分量的DCT系数随机嵌入水印比特,嵌入了多个灰度数字盲水印.该算法预估了水印嵌入量,提取水印无需宿主图像和水印图像,仿真实验表明能有效抵抗滤波、加噪、剪切、JPEG有损压缩,具有较好的鲁棒性.     

基于DCT的半脆弱水印算法

数字水印技术成为多媒体信息安全研究领域的一个热点问题.对变换域DCT(discrete cosine transform)域的半脆弱性的数字水印算法进行了研究.该算法首先生成数字水印:水印图像是灰度图,根据特定的分组表及公式将所有系数进行分组,进而生成二进制水印信息;然后将宿主图像进行基于分块DCT变换,最后将水印信息嵌入到各分块DCT域的中低频系数中.该算法对一些常见的图像处理具有一定的鲁棒性,同时具有一定的检测篡改的能力,可以定位到空间域的8*8块.试验结果验证了该方法的有效性.     

HSV颜色空间的彩色图像数字水印算法

提出了一种新的基于HSV颜色空间的彩色图像数字水印算法.该算法采用彩色图像作为水印嵌入到原始彩色图像中.算法根据HSV颜色空间的特点,首先将RGB格式的彩色水印图像转换到HSV颜色空间内,然后分别将水印图像的H、S、V三层进行分块DCT变换,对每一个子块保留左上角的系数,将其它的系数替换为0,得到嵌入矩阵,使得嵌入的有效信息大为减少.再将原始彩色图像转换到HSV域内,对原始图像的H、S和V平面进行分块DCT变换后,将变换后的H、S、V层水印信息分别嵌入到原始图像的H、S和V层变换后的中频和低频系数中,最后通过DCT逆变换和颜色空间转换,将嵌入水印的图像转换成RGB的图像,得到嵌入水印的图像,完成水印的嵌入过程.水印图像小于载体图像,利用冗余嵌入提高了水印的鲁棒性.     

基于系数关系的DCT域数字图像水印

提出了一种DCT域的数字图像盲水印算法,该算法将图像进行8*8分块后对各块图像进行DCT变换。之后将水印信息嵌入到选取的中频系数之间的关系中;提取水印时不需要原始图像,实现了盲检测;而且水印嵌入位置可由密码控制,增强了算法的保密性和灵活性;不可感知性和鲁棒性可调。仿真实验结果表明该算法在保证水印不可感知性的情况下,对一些常见的恶意攻击具有良好的鲁棒性。     

一种抗JPEG压缩的彩色图像半脆弱水印算法

提出了一种抗JPEG有损压缩的真彩图像半脆弱水印算法.采用YCbCr颜色空间,水印的生成和嵌入均在亮度分量进行.由图像基本特征生成水印,嵌入时对亮度分量进行分块DCT变换,选择每个分块的中频系数作为水印的嵌入位置.实验表明,该算法透明性好,而且对JPEG有损压缩具有较强的鲁棒性,对剪切、替换等恶意篡改做出报警并确定篡改位置.水印检测不需要原始图像,水印系统的安全性依赖于图像的特征及其置乱函数,因此,具有较高的安全性.     

基于混叠DCT频域灰度级盲水印多重嵌入算法

基于扩展频谱通信技术，对宿主图像的频域进行2维DCT变换，采用保持图像亮度的JND（just noticeable distortion）门限值和多数字基底对宿主图像DCT频域进行选块，对中频分量的DCT交流系数分组嵌入水印比特，以随机二值序列对高低频分量的DCT系数的水印比特嵌入进行控制，使多个数字盲水印信号载波传输于混叠的DCT频带。该算法可预估水印嵌入量，提取水印无需宿主图像和水印图像，仿真测试实例表明，该算法能有效抵抗滤波、加噪、剪切、JPEG有损压缩，具有较强的顽健性和鲁棒性。     

一种新的三维模型水印频域算法

从提高三维模型数字水印的鲁棒性和效率出发,提出一种新的频域水印算法。该算法利用网格拓扑结构,构建出目标顶点所处的局部几何空间,进而提取出适用于DCT变换的信息序列,修改频域系数嵌入水印;然后通过逆向DCT转回空域信号,修改目标顶点在局部几何空间中的位置得到含水印模型。算法实现简单,水印检测无需预处理,且能有效抵抗平移、旋转、缩放、剪切、网格简化等攻击。实验结果表明,该算法具有很好的鲁棒性、水印的不可感知性、水印检测高效准确的优势。     

一种新的三维模型水印频域算法

从提高三维模型数字水印的鲁棒性和效率出发．提出一种新的频域水印算法。该算法利用网格拓扑结构．构建出目标顶点所处的局部几何空间．进而提取出适用于DCT变换的信息序列,修改频域系数嵌入水印：然后通过逆向DCT转回空域信号,修改目标顶点在局部几何空间中的位置得到含水印模型。算法实现简单．水印检测无需预处理．且能有效抵抗平移、旋转、缩放、剪切、网格简化等攻击。实验结果表明,该算法具有很好的鲁棒性、水印的不可感知性、水印检测高效准确的优势。     

基于DCT变换的数字水印算法研究

提出了一种基于DCT变换嵌入到图像的中频带水印改进算法。该算法在DCT变换水印算法的基础上,调整DCT对应系数,然后将其嵌入到原始图像的中频系数中。从实验结果来看,该算法真正做到水印的盲监测,实现水印能够抵抗常见的噪声、裁剪、JPEG压缩等攻击,使水印具有较好的不可见性和鲁棒性。     

一种新的基于DCT系数置换的鲁棒水印算法

针对水印算法中存在的不可见性和鲁棒性之间的矛盾,提出了一种新的水印算法.该算法一方面综合考虑人类视觉特性和JPEG压缩原理选择恰当的嵌入位置,利用所选系数对的大小关系嵌入水印;另一方面自适应地对嵌入水印后相应位置的DCT系数进行增强处理,从而使水印具有良好的不可见性,又大大增强了水印的鲁棒性,且可实现盲检测.具体分析了不可见性和抗JPEG压缩性能与水印嵌入强度的关系,理论分析及实验表明该算法能够有效的抵抗JPEG压缩、噪声、滤波、剪切等各种攻击,具有较好的实用价值.     

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.