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鲁棒性是水印的重要特性之一,水印鲁棒性强度恰当与否决定着水印的好坏。因此,水印鲁棒性衡量至关重要。文中提出了新的衡量水印算法,新算法将被攻击后的水印作为函数变量。首先对水印被攻击后给水印所造成的损坏进行分类,之后以原始水印作为衡量水印鲁棒性的基准,通过计算提取水印偏离原始水印程度的值,将所得到的值使用中介真值程度度量的方法对水印鲁棒性进行衡量。中介真值程度度量的方法在数字水印上的应用尚属首次。最后进行了算法分析。 相似文献
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基于离散小波变换的盲水印研究与仿真 总被引:1,自引:1,他引:0
研究优化水印安全性问题.由于水印图像应具备版权信息和密钥条件,针对目前音频水印算法中水印容易被提取,且检测水印时均需要原始水印图像,导致水印安全性,鲁棒性无法保证.提出了基于离散小波变换的混沌加密的音频数字水印盲算法.将混沌原理引入音频水印中,改善了水印的安全性,同时根据信号的能量对水印进行了量化嵌入,改善了水印的鲁棒性.首先利用密钥对二值水印图像进行随机置乱;然后将经过随机置乱处理的含有版权信息的二值水印图像嵌入到原始音频信号中.在水印检测过程中利用已知的密钥对水印进行重构.仿真证明,在不知道密钥的情况下,无法得出水印图像,为设计提供了依据. 相似文献
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根据可见水印性质和载体图像的噪声掩蔽性在小波域进行可见水印算法的研究。提出了一种根据载体图像视觉掩蔽性进行水印嵌入强度的方案。在此基础上又结合水印图像的纹理特性对于高频系数水印嵌入强度进行重新调制。另外还对水印可见性质量评估进行了探讨。实验表明,改进后的算法水印可见性质量更好。 相似文献
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以鲁棒性为目标的数字多水印研究 总被引:3,自引:0,他引:3
单个的数字水印算法或方案难以应付多种攻击方法的攻击,为此,文章对应用多水印方法提高水印抗攻击鲁棒性问题进行探讨,根据水印抵抗攻击的能力,给出了水印抗攻击鲁棒性的分类定义,同时根据这种能力提高的程度对多水印进行了分类,并由此引申出相关的命题.深入探讨了多水印带来的主要问题,并提出了解决多水印问题的多目标优化数学模型.以视频水印为例,对抗几何变换攻击和帧同步攻山的视频水印联合进行了实验,实验结果表明多目标优化模型能够有效解决多水印带来的问题,且多水印方法能够提高水印抵抗攻击的能力. 相似文献
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提出了一种新的图像数字盲水印算法。在水印嵌入过程中,用一个单元模板表示一个水印图像像素;在检测过程中,计算单元模板和嵌入水印后图像的小波变换系数的相关值,进行适当的门限处理就能提取出水印。水印检测不需要原始图像数据和水印位置信息,实现了水印图像的自同步盲检测。为了进一步提高该水印算法的鲁棒性和改善检测结果,在水印检测前使用拉普拉斯算子对图像进行锐化处理,使得所嵌入水印能抗击更多攻击种类,并使检测结果更清晰。在检测前加入锐化处理步骤,可以减小水印嵌入强度,而能得到同样的检测效果,因此也增强了水印的隐蔽性。实验表明,该算法具有较好的水印隐蔽性和鲁棒性。 相似文献
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提出了利用遗传算法在关系数据库海量的元组中选择最优元组进行水印嵌入,实现了水印短时间内的优化嵌入,大大提高了水印嵌入的效率。同时,采用纠错编码技术和投票选取机制来增加水印的鲁棒性。实验结果表明,这种关系数据库水印优化方案大大提高了水印嵌入的效率,并可以较好地协调水印的鲁棒性和数据库可用性之间的矛盾,实现了关系数据库水印的优化。 相似文献
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杨林娟 《计算机光盘软件与应用》2014,(10):199-201
本文针对水印的嵌入方法提出一种综合的技术,即在变换了的水印载图上再嵌入水印这样经反变换后得到的嵌有水印的图像不能被人眼感知明显的变化,而对水印图像进行基于混沌序列的加密则进一步增加了水印的安全性并同时提高了水印的鲁棒性。 相似文献
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数字水印是实现版权保护的有效技术,视频水印研究是目前水印技术领域的一个热点。该文综合国内外的视频水印技术的发展,对水印的特点、技术分类、嵌入提取算法和攻击技术进行了全面的介绍,指出了典型算法,并对视频水印技术的发展趋势进行了展望。 相似文献
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Julie J.S. Parker 《International Journal on Digital Libraries》2004,4(2):124-136
Publications such as consumer magazines rely heavily on image libraries as sources for the images they use in their issues. Traditionally, magazine editorial staff have discussed their image requirements over the telephone with library staff and the library has conducted the search. Many libraries have now developed Web sites and their customers search them for images themselves. A minority have e-commerce capabilities, and enable customers to purchase and download digital images from their sites. This survey found that magazine staff do not often choose to search digital libraries, preferring instead to continue to contact the library by telephone. Most also choose not to buy the use of digital images, but prefer to continue to work with conventional transparencies and slides. The reasons for these preferences, and the reasons they are unlikely to change in the short term, are explored. 相似文献
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Jeffrey Pomerantz June Abbas Javed Mostafa 《International Journal on Digital Libraries》2009,10(1):1-13
Many digital library topics may be taught using digital library applications, in the context of project-based digital library
courses. Several digital library applications exist, and these applications are used as teaching tools to illustrate the functionality
of digital libraries as well as the design decisions that go into them. Using digital library applications as teaching tools
provides a valuable learning experience for students, and may provide useful feedback to the developers of DL applications.
This paper identifies and explores DL topics that may most effectively be taught using DL applications, in the context of
project-based DL courses. 相似文献
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A digital twin (DT) is an effective means of achieving physical and information fusion and has great potential for achieving a new paradigm of cutting process (CP) intelligence. This paper traces the relevant studies of digital technology in manufacturing and proposes a bionic digital brain (BDB) as the intelligent core of a digital twin-cutting process (DTCP) framework. The BDB was built with digital neurons (DN) as the basic functional unit, and the reaction mechanism between the DN stimulated the BDB to compute intelligently in real time (RT). The left brain obtains the prophetic theoretical processing information through the DN. The right brain receives actual perceptive processing information through the DN. After the corpus callosum fuses the left and right brain information, the DN outputs the optimal control solutions in RT to ensure demand. The details of monitoring, predicting, optimizing, and controlling the CP based on this framework are described in detail through a case study, demonstrating the powerful information processing capability of the BDB and the RT precision intelligent machining effects. The developed DTCP system confirmed the feasibility and effectiveness of the proposed framework. It provided a theoretical and technical reference for applying and promoting DT technology in the CP. 相似文献
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现代社会以手机和个人数字助理为代表的小型手持电子设备已经成为人们不可或缺的日常工具。随着信息和通信技术的发展,这些手持设备功能越来越增强,普及度越来越高,在各类案件中都可以见到这类数字手持设备的身影。因而对于这一类小型数字电子设备取证成为紧迫性的新研究领域。对这一类数字取证现状和相应工具作一综述。 相似文献
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We investigate the performance and the scalability metrics of a Digital Information Service framework that is used for unifying and federating online digital entities by retrieving and managing information located on the web. The Digital Information Service consists of tools and web services for supporting Cyberinfrastructure based scientific research. This system supports a number of existing online Web 2.0 research tools (social bookmarking, academic search, scientific databases, journal and conference content management systems) and aims to develop added-value community building tools that leverage the management and federation of digital entities and their metadata obtained from multiple services. We introduce a prototype implementation and present its evaluation. As the results indicate, the proposed system achieves federation and unification of digital entities coming from different sources with negligible processing overheads. 相似文献
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This paper interrogates the currently pervasive discourse of the ‘net generation’ finding the concept of the ‘digital native’ especially problematic, both empirically and conceptually. We draw on a research project of South African higher education students' access to and use of Information and Communication Technologies (ICTs) to show that age is not a determining factor in students' digital lives; rather, their familiarity and experience using ICTs is more relevant. We also demonstrate that the notion of a generation of ‘digital natives’ is inaccurate: those with such attributes are effectively a digital elite. Instead of a new net generation growing up to replace an older analogue generation, there is a deepening digital divide in South Africa characterized not by age but by access and opportunity; indeed, digital apartheid is alive and well. We suggest that the possibility for digital democracy does exist in the form of a mobile society which is not age specific, and which is ubiquitous. Finally, we propose redefining the concepts ‘digital’, ‘net’, ‘native’, and ‘generation’ in favour of reclaiming the term ‘digitizen’. 相似文献
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Definitions of 3-D digital surface and plane are introduced. Many geometric properties of these objects are examined. In particular, it is shown that digital convexity is neither a necessary nor a sufficient condition for a digital surface element to be a convex digital plane element, but it is both necessary and sufficient for a digital surface to be a digital plane. Also algorithms are presented to determine whether or not a finite set of digital points is a (convex) digital plane element. 相似文献
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In this paper, a new fabrication method for digital microfluidics is proposed. In which, paper, graphite, and adhesive tape are used as substrate, electrodes, and dielectric layer, respectively. The graphite is sprayed over a template on the paper substrate. Two different water repellants are used as the hydrophobic layer, which replace with expensive materials such as Teflon-AF®. The paper substrate is low cost, available, and flexible. The proposed device is disposable, and its fabrication procedure is simple, fast, and low cost which allows creation of a new device for each individual experiment. Therefore, problems such as adsorption and dielectric breakdown will not occur in this type of digital microfluidics. This device can perform two types of droplet operations, merging and moving on droplets in volumes of 15–50 μL. 相似文献
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This paper provides a review of recent developments in multirate digital filters and attempts to fill a long existing gap between multirate digital filters and multirate sampled-data feedback control systems. 相似文献