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介绍了数字图像水印技术的原理、主要特征,阐述了目前图像水印信号的产生方法,分析了图像水印技术的处理算法,探讨了图像水印技术面临的挑战及其发展趋势。 相似文献
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High-School Students' Attitudes Regarding Procedural Abstraction 总被引:1,自引:0,他引:1
Bruria Haberman 《Education and Information Technologies》2004,9(2):131-145
During the last decade a new computer science curriculum has been taught in Israeli high schools. This curriculum introduces CS concepts and problem-solving methods independently of specific computers and programming languages, along with the practical implementation of those concepts and methods encountered in actual programming languages. The advanced study unit of the curriculum, Software Design, introduces the students to various aspects of software systems design through the use of abstract data types (ADTs). One main goal of the unit is to develop abstract thinking skills and problem-solving abilities. More specifically, the unit presents principles such as procedural abstraction, data abstraction, information hiding, modularity, efficiency, and reuse of code.We present the results of a preliminary study whose aim was to assess students' attitudes regarding procedural abstraction. The research population consisted of high-school students who attended the Software Design course (beginners), and a control group of undergraduate CS students (advanced). The results of the study clearly indicated a significant difference between the attitudes of the two groups. We found that the advanced students preferred algorithms that were formulated to some extent with high-level abstraction; however, they encountered a cognitive barrier when dealing with algorithms that they had evaluated as too abstract for them. However, beginners felt more comfortable with algorithms with low-level abstraction. Nevertheless they showed open-mindedness toward some degree of procedural abstraction. The results of the study were used to design scaffolding problem-solving tools for algorithm development, utilizing procedural abstraction techniques that can be adapted to various student populations (Haberman, B. (2002) SIGCSE Bulletin, 34(4), 60–64). 相似文献
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信息隐藏技术及其在数字图书馆版权保护中的应用 总被引:4,自引:0,他引:4
简要介绍了信息隐藏技术的定义、特性、分类和隐藏方式。结合数字图书馆的实际,论述了信息隐藏技术在数字图书馆版权保护中的应用。 相似文献
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基于资源保存理论,探究"以团队成员为领导来源"的共享型领导和"组织正式任命"的服务型领导如何共同助推团队创新.采用"多来源和多时点"的数据收集方式,获得88个知识团队的配对数据(n=418).研究结果表明,共享型领导正向影响团队创新绩效,服务型领导在二者之间发挥有中介的调节作用;当服务型领导水平高时,共享型领导通过减少团队知识隐藏进而提升团队创新绩效的作用更强.上述结果有助于深入认识共享型领导与团队创新绩效之间的潜在中介机制和边界条件,并为团队领导模式变革与创新管理提供有益的启示. 相似文献
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柳玲 《鹭江职业大学学报》2014,(5):67-71
针对数据隐藏算法嵌入容量有限的问题,提出一种新的插值方法,将其应用到数据隐藏领域中,并给出一种基于改进插值的可逆数据隐藏算法.该算法在信息嵌入时,先用文中提出的插值方法对原始宿主图像进行扩展,扩展时,每个扩展像素以4个宿主像素点作为参考,通过计算得出均值,再将其分配到待扩展的位置上,信息嵌入后可以无损地进行信息提取和图像的恢复.实验结果表明,该数据隐藏算法在嵌入容量、图像视觉质量方面均取得很好的效果,相比其他的数据隐藏算法,最大嵌入容量提高了24.78%-39.29%,最大藏量下的信噪比均保持在39 dB以上. 相似文献
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基于Qt库设计并实现了一个基于静止图像的信息隐藏算法及对应的提取算法。算法以基于空域隐藏算法的最低有效位替换算法为核心思想,为需要隐藏的信息设计了一个特有的格式,以该格式输出的信息作为被隐藏的信息的主体,嵌入到载体图像中,实现了信息隐藏的目的;同时根据信息隐藏的过程,实现了一个信息提取的算法,从而将隐藏信息提取出来。实验结果表明,该算法达到了将文本和文件隐藏到静止图像中的目的。 相似文献