基于音频特征的抗去同步攻击数字水印算法

抗去同步攻击的强鲁棒数字音频水印方法研究是一项富有挑战性的工作.本文结合数字音频自身特征,提出了一种基于音频内容的抗去同步攻击数字水印算法.该算法首先根据数字音频的局部能量特征,从原始载体中提取出稳定的特征点;然后以音频特征点为标识,确定用于水印嵌入的候选音频段;最后采纳量化调制策略,将数字水印嵌入到音频载体内.进行数字水印检测时,系统通过分析音频内容提取特征点,再以特征点为标识提取水印信息,水印检测无需原始音频信号参与.仿真实验结果表明,本文算法不仅具有较好的不可感知性,而且对常规信号处理(MP3压缩、低通滤波、添加噪声等)和去同步攻击(随机剪切、幅度缩放、时间延展、抖动等)均具有较好的鲁棒性.     

一种基于特征点检测的音频数字水印算法

对音频数字水印系统,提出了一种基于特征点检测的水印算法.利用特征点的检测进行水印嵌入点的准确定位,应用离散余弦变换进行水印的嵌入,水印的检测过程中不需要原始信号的参与,实现了水印信号的盲检测,并较好地解决了音频数字水印检测中的同步问题.仿真实验表明该算法对低通滤波、重采样、压缩编码等信号处理和破坏水印检测同步特性的恶意攻击有较强的稳健性.     

基于支持向量机的鲁棒盲水印算法

提出了一种基于支持向量机的鲁棒盲水印算法.该算法首先用多尺度Harris-Laplace检测算子从载体图像中提取出稳定的特征点,然后根据特征自适应确定局部特征区域,在特征区域选择一些点作为嵌入水印的点,结合图像的邻域相关性,根据灰度图像特点,选取特征向量作为SVR训练模型,进而利用SVR进行预测,调节嵌入点的像素值进行水印的嵌入和提取.实验结果表明,用该技术嵌入水印后的图像具有很好的图像感知质量,时常规信号处理乖去同步攻击特别是JPEG压缩具有较强的鲁棒性.     

基于第二代Bandelet变换的抗几何攻击图像水印

抗几何攻击的鲁棒图像水印设计是目前水印技术研究的难点和热点之一. 文中分析了图像的Bandelet变换特性, 提出了一种以图像特征点矢量集为特征向量的回归支持向量机(Support vector regression, SVR)和第二代 Bandelet变换的抗几何攻击图像水印算法,采取的主要方法包括: 1)在Bandelet变换提取的刻画图像局部特征的几何流系数上, 采用奇偶量化嵌入水印; 2)利用Harris-Laplace算子从归一化的含水印图像中提取具有几何形变鲁棒性的图像特征点,构造特征点矢量集 作为特征向量,应用回归支持向量机对几何变换参数进行训练学习; 3)水印检测时, 先利用SVR训练模型得到待检测图像所受几何攻击的参数并作几何校正,然后通过奇偶检测器盲提取水印.仿真实验表明,所提出的水印算 法不仅具有良好的透明性,而且对常规图像处理、一般性几何攻击和组合攻击均具有良好的鲁棒性.     

基于音频特征的多小波域水印算法

基于对音频特征的分析,提出了一种多小波域的水印算法.结合人类听觉系统的时频掩蔽特性,该算法分析音频帧的过零率及时域能量,确定用于嵌入水印的帧.利用音频的分抽样特征和多小波变换在信号处理中的优势,将每一个音频帧进行分抽样为两个子音频帧并分别将其变换到多小波域.利用两个子音频帧在多小波域的能量来估计所嵌入水印的容量,并根据它们的能量大小关系完成水印的嵌入.水印的提取过程转为一个使用支持向量机进行处理的二分类问题.实验结果验证了所提出的水印算法能根椐音频自身的特点寻找到适合用于嵌入水印的音频帧,且能动态调整水印的嵌入强度,在保证听觉质量的同时提高了水印的鲁棒性.     

基于音频内容与维特比解码的音频数字水印算法

利用音频自身特征作为水印的同步信号有利于提高音频水印的鲁棒性。提出了一种基于音频内容分析的算法,算法先经过音频内容分析得到一组特征点,在特征点后面的音频中嵌入水印。水印检测时,同样先分析待测音频得到特征点,利用特征点后面的音频提取出有意义的水印。为了提高水印的检测速度,提出采用维特比（Vitebi）解码技术判决水印。实验结果表明,算法对加噪、低通滤波等具有一定的鲁棒性。     

基于Contourlet域特征点的抗几何攻击水印方法

有效抵抗几何攻击的水印算法是目前水印技术研究的难点之一,很小的几何变形就可能使大多数水印算法失效.对图像Contourlet变换和Harris-Affine算子的特性进行了分析和讨论,在此基础上提出了一种以仿射不变特征点的基于Contourlet的抗几何攻击水印算法.首先,用Contourlet变换提取出多尺度、多方向的纹理信息;再用Harris-Affine检测算子从变换域的中、低频方向子带中提取出仿射不变特征点,结合自适应局部结构的特征尺度确定特征区域,并用U变换对其归一化处理,水印就自适应地嵌入到归一化后的区域中;水印嵌入采纳矢量量化的策略,将水印信息重复嵌入到不同方向子带、多个不相交的局部仿射不变特征区域.检测时,利用特征点实现水印的重同步,采用多数原则来提取水印的位信息,无需求助于原始图像.仿真结果表明,算法不仅具有较好的透明性,而且对常规信号处理和去仿射攻击均具有较好的鲁棒性     

基于对象传播神经网络的抗TSM攻击音频水印算法*

提出了一种基于对象传播神经网络的抗TSM攻击音频水印算法。利用CPN自学习和自适应的特征,通过自适应改变段长的分段算法,选用具有较强稳定性的小波低频系数方差作为输入向量训练CPN,建立音频特征与水印信号的对应关系,以达到嵌入水印的目的。实验结果表明,该算法对常规音频信号处理和TSM等同步攻击具有很强的鲁棒性。     

可有效抵抗一般性几何攻击的数字水印检测方法

以回归型支持向量机理论为基础, 结合性能稳定的伪Zernike矩和Krawtchouk矩, 提出了一种可有效抵抗一般性几何攻击的强鲁棒数字图像水印检测算法. 该算法首先选取图像的低阶Krawtchouk矩作为特征向量, 然后利用SVR对几何变换参数进行训练学习并对待检测图像进行数据预测, 最后对其进行几何校正并提取水印信息. 仿真实验结果表明, 该数字图像水印检测算法不仅具有较好的不可感知性, 而且对常规信号处理和一般性几何攻击均具有较好的鲁棒性.     

基于Blakley方案的音频水印分存算法

提出了一种基于Blakley密钥共享方案的音频水印分存算法。算法将密钥分存的思想引入到音频水印算法中,将水印分存到音频数据的不同段中,检测时只需提取出部分水印信息就可以恢复出原始水印。算法同时采用了Bark码来解决剪切攻击带来的同步问题,并利用逼近信号统计特征和纠错码技术来提高算法的鲁棒性。实验证明,算法具有较强的抗剪切攻击能力。     

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.     

Call for Papers The 6^th International Conference on Grid and Cooperative Computing

Recent years have seen rapid advances in various grid-related technologies, middleware, and applications. The GCC conference has become one of the largest scientific events worldwide in grid and cooperative computing. The 6th international conference on grid and cooperative computing (GCC2007) Sponsored by China Computer Federation (CCF),Institute of Computing Technology, Chinese Academy of Sciences (ICT) and Xinjiang University ,and in Cooperation with IEEE Computer Soceity ,is to be held from August 16 to 18, 2007 in Urumchi, Xinjiang, China.     

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.     

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.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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