基于离散小波变换的数字音频水印

该文根据小波变换的时频分析特性,提出了一种在数字音频信号中加入二值标志图像的水印嵌入方法。该方法结合人的听觉特性,将水印和原始音频数据分别进行小波变换,将变换后水印和音频小波系数更好地融合,使水印不可感知。实验结果表明,利用该方法嵌入的二值标志图像水印对一般的信号处理具有较好的不可感知性和鲁棒性。所提出的方法在数字音频的版权保护和身份验证方面具有特殊的保密性。     

基于LabVIEW平台的数字音频水印系统

用LabVIEW实现了在数字音频中嵌入二值图像水印。系统主要由水印的嵌入与水印的提取两部分组成。由LabVIEW的"简易读取声音文件"节点,将音频信号读取进来。首先对音频信号进行离散小波分解,根据人耳听觉特性选择嵌入点,然后修改原始音频信号小波系数小数点后有效位的奇偶性进行水印数据的嵌入,在提取水印时,检测小波系数小数点后有效位的奇偶性进行水印提取。使用LabVIEW实现了既有嵌入程序又有提取程序的数字音频水印系统。     

基于小波包分析的数字音频双水印算法

针对以往双水印算法鲁棒性不高和定位不准确的问题,提出一种基于小波包分析的数字音频双水印算法。算法对原始音频信号进行小波包分解,在得到的低频系数和中低频系数中嵌入零水印和半脆弱水印。改进的零水印算法鲁棒性有了很大的提高,能更好地完成音频信号的版权保护;对中低频系数采用量化的方法嵌入二值水印图像,有别于以往算法需将二维图像转换为一维序列,不会对零水印的提取产生影响。该方法对一系列常规处理和幅度缩放都有较好的鲁棒性,不但能确定水印图像遭恶意篡改的位置,而且能够定位原始载体音频的篡改位置,真正实现了对音频信号的内容认证。     

增强鲁棒性的音频水印算法

提出了一种基于离散小波变换的数字音频水印盲检算法.算法选择在小波系数中嵌入水印,将同步化位元码引入到音频水印的研究中,针对切割或插入额外音频段的攻击有较好的抵抗能力,并且通过重复地将水印嵌入到音频信号中,增强了鲁棒性,提取水印时不需要原始音频信号.实验结果表明,该方法具有良好的鲁棒性和不可听见性.     

一种基于小波域的盲检测音频水印算法

该文提出了一种基于离散小波变换的数字音频水印盲检算法。本算法选择在小波系数的偶数点嵌入水印,将混沌理论引入到音频水印系统的研究中,利用混沌序列将一幅有意义的二值图像加密后嵌入到原始音频的DWT域中,提取时不需要原始音频信号。仿真实验证明了算法的鲁棒性和不可感知性。     

数字音频信号的脆弱水印嵌入算法

该文给出了量化系数嵌入水印比特信息的基本原理，在此基础上提出了数字音频信号的脆弱水印嵌入算法。该算法充分利用离散子波变换的多分辨率特性，通过等概率随机量化音频信号不同子带的子波系数嵌入视觉可辨别的水印－二值图像。仿真实验结果表明，该文提出的数字音频信号脆弱水印嵌入算法对有损压缩、滤波和重新采样等操作具有很强的敏感性。     

基于小波域的均值量化数字音频水印算法*

提出了一种均值量化的小波域数字音频水印算法。均值量化可以减少攻击对水印的影响,算法选择合适的小波基对音频信号进行小波分解,对其中的中、低频系数进行均值量化,嵌入水印,水印提取过程不需要原始音频信号。实验结果表明,与一般水印量化算法相比,该算法对MP3、重量化、重采样、低通滤波和噪声干扰等信息处理型攻击具有更好的鲁棒性。     

多重水印嵌入的DWT-SVD音频公开水印算法

提出了一种基于离散小波变换（Discrete Wavelet Transform,DWT）域与奇异值分解（Singular Value Decomposition,SVD）的多重嵌入数字音频水印算法.算法在嵌入水印前采用混沌加密与图像置乱对水印进行双重加密,在选取音频载体的多段数据中,利用DWT的多分辨率特性与SVD值稳定特性的特点,先对各段数据进行多级DWT变换,然后在低频部分选取连续的若干个系数组成矩阵,并对矩阵进行SVD分解,再把加密后的每位水印信息采用量化方法嵌入到SVD值中,实现了水印的多重嵌入.实验表明,该水印方法效率高,透明性好,对常见的音频信号处理具有较强的鲁棒性.     

基于小波变换和倒谱变换的音频水印技术

提出了一种基于小波变换和倒谱变换的数字音频水印算法。该算法将音频信号进行小波分解,选取低频系数。对低频系数进行倒谱变换,并根据统计均值思想,把水印嵌入到倒谱域中,实现了在音频信号中嵌入二值图像。实验结果表明该算法具有比较好的鲁棒性,能抵抗常见信号的攻击,如低通滤波、重采样、重量化、有损压缩、音量变化、添加白噪声等。     

基于小波变换和倒谱变换的音频水印技术

提出了一种基于小波变换和倒谱变换的数字音频水印算法。该算法将音频信号进行小波分解,选取低频系数。对低频系数进行倒谱变换,并根据统计均值思想,把水印嵌入到倒谱域中,实现了在音频信号中嵌入二值图像。实验结果表明该算法具有比较好的鲁棒性,能抵抗常见信号的攻击,如低通滤波、重采样、重量化、有损压缩、音量变化、添加白噪声等。     

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.     

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.     

Editorial: Special issue on recent advances in hybrid control theory and applications

正The demands of a rapidly advancing technology for faster and more accurate controllers have always had a strong influence on the progress of automatic control theory.In recent years control problems have been arising with increasing frequency in widely different areas,which cannot be addressed using conventional control techniques.The principal reason for this is the fact that a highly competitive economy is forcing systems to operate in regimes where     

Information for Authors

正Aim The Journals of Zhejiang University-SCIENCE(A/B/C)areedited by the international board of distinguished Chinese andforeign scientists,and are aimed to present the latest devel-opments and achievements in scientific research in China andoverseas to the world’s scientific circles,especially to stimulateand promote academic exchange between Chinese and for-eign scientists everywhere.     

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.