基于DCT系数符号的音频零水印算法

为了解决现有音频水印算法透明性与鲁棒性之间的矛盾,提出了一种基于DCT系数符号的音频零水印算法。算法按水印尺寸对时域音频数据做等长分帧,求取每帧数据的绝对值平均值,依次按时序做离散余弦变换（ DCT）。算法选取数值最大的DCT系数,利用水印属性与最大DCT系数符号做异或运算,得到水印密钥,实现了零水印的嵌入。实验结果表明该算法可以很好地抵抗各类常规的信号处理破坏,水印鲁棒性较强。     

一种基于量化DCT域音频水印新算法

提出一种新的基于量化DCT域的音频水印算法,根据DC分量和AC分量在水印的鲁棒性和不可听性中起着不同的影响来设计水印算法,使水印的鲁棒性和不可听性得到更好的权衡。首先,把音频数据分成含有8个数据的不重叠块,然后,对每个数据块进行DCT变换;通过对DCT系数中DC分量和第四AC分量进行轮流调制来完成水印嵌入,每个数据块嵌入1 bit信息。实验表明该水印算法对于叠加噪声,有损压缩,重量化等常见的数字信号处理具有较好的鲁棒性,同时,水印系统具有很好的不可听性。     

一种基于双重加密的DWT-DCT域音频公开水印算法

提出了一种新的基于DWT和DCT音频公开水印算法。算法应用图像置乱与混沌原理对水印图像进行双重加密,并充分利用DWT的多分辨率特性与DCT的聚能特性对选取的多段音频进行处理,然后再把加密后的水印嵌入到各段的DCT低中频系数的量化中。仿真实验表明,该算法高效、安全性能好,且具有较好的不可感知性,对常见的音频处理具有较好的鲁棒性。     

基于量化的DCT域数字音频水印方法

数字水印的主要研究目的是版权保护。依据DCT域系数的特点,提出了一种DCT域的音频水印算法,先将音频数据按固定长度分段,然后对每段进行DCT变换,利用当前水印调制DCT直流系数,达到嵌入目的。实验表明,算法具有较好的透明性,并经Stirmark软件攻击测试具有较强的鲁棒性。     

一种基于段分类的音频水印技术

提出了一种利用“段分类”的 DCT域自适应音频水印方法 ,可应用于音频信息的版权保护。首先将原始音频信号分为长度为 N的段 ,利用听觉系统 (HAS)的掩蔽效应 ,将音频段分为三类 ,然后对所有的段进行DCT变换。根据音频段的分类效果 ,不同强度的水印分量被嵌入到不同音频段中的部分 DCT低频系数中。实验结果表明了该方法具有良好的隐秘性和鲁棒性     

改进的DCT域音频水印算法

水印的稳健性、透明性是影响水印鲁棒性的重要指标。大多数的DCT(discrete cosine transform)域音频水印算法是通过量化系数的方法嵌入水印,但是算法选取的嵌入策略、嵌入强度和嵌入位置不能达到一个满意的效果。针对这些不足,提出一种改进的DCT域量化算法。采用数据分段后隔段嵌入的嵌入策略,可以明显地改善水印的透明性;根据所分段的段能量和,采取分等级的方式确定嵌入强度,这样减少了计算复杂度;嵌入时选取高、中、低频3个系数重复嵌入;最后采用三次样条插值方法进行攻击恢复数据量。对该算法进行了Matlab仿真,通过主观和客观标准的评价,实验结果表明了该算法具有更好的稳健性和透明性。     

一种基于DCT和SVD的音频水印算法

提出一种基于离散余弦变换(DCT)和奇异值分解(SVD)的音频水印算法.该算法将原始音频进行分段后再分块,对每一块进行DCT 变换,利用Zig-Zag算法将变换后的系数分成4个象限,通过对每个象限进行SVD变换得到对角阵,并在对角阵的第1个元素内嵌入水印.实验结果证明,该算法具有良好的透明性,在嵌入强度为0.2时峰值信噪比较高,同时可以抵抗重采样、回声、噪声等攻击,具有较高的鲁棒性.     

基于音频特征的自嵌入数字水印技术

论文提出一种用于音频数据内容认证与恢复的数字水印算法。该算法基于音频主要特征生成水印,并自嵌入到原始音频数据,使得水印能检测和定位对音频的篡改,并能对篡改部分进行近似恢复。其基本思路是把音频分段,每段的主要DCT系数经过量化和加密后,作为水印嵌入另一个音频段的LSB最低位之中。这样能保证音频恢复时有较好的质量。水印是使用音频的主要特征DCT系数及其位置,故能实现盲提取。     

一种DCT域自适应音频水印算法*

数字水印技术中水印强度是影响水印鲁棒性的重要参数。当前大多数的水印算法均利用实验来确定水印强度,但实验具有很大的随机性,得到合适的水印强度需要大量的实验。提出了一种DCT(discrete cosine transform)域基于信噪比(signal noise ratio,SNR)水印强度自适应的音频水印。首先将载体音频分帧,然后根据对嵌入水印后音频品质要求的SNR计算各帧的水印强度,选择可嵌入强度大的帧,将一个水印比特信息嵌入一帧的DCT的直流系数,水印强度将自适应于各帧。实验结果证明了该算法具有较好     

一种基于D CT的序列分组水印算法

在保证鲁棒性前提下,为了进一步提高水印的不可感知性,提出了一种基于DCT变换的二值序列分组数字水印算法。该算法选择载体图像的部分中频系数作为可嵌入的位置空间,同时将水印的分组数值映射到该空间中的一个具体系数作为实际内嵌位置。算法利用一个DCT系数嵌入多比特水印信息,减少了水印嵌入过程中需要修改的系数量,提高了水印算法的感觉容量。实验结果表明,该算法能够实现水印嵌入位置的随机选取,并对典型攻击具有鲁棒性。     

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.     

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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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