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共找到4条结果
  • 基于像素对平均预测的可逆信息隐藏

    可逆信息隐藏之所以可逆是因为现存方案都以图像中某种不变的特性为准来完成可逆操作.基于此原理,区别于现存方案,选择两像素间的平均值作为不变特性,再借助于直方图平移的思想提出了一种基于像素对平均预测的直方图平移的可逆信息隐藏方案.它是在保证每次操作时两像素间平均值保持不变的前提下利用差分直方图思想完成嵌入和提取信息并无损恢复原始图像的操作.实验结果证明本方案在保证良好的图像质量前提下嵌入容量也得到提高,同时产生较少的辅助信息,与相关研究方案相比具有良好的优越性.
    郑淑丽,章佳佳,胡东辉,张云玲,郑森 - 系统仿真学报
    文章来源: 万方数据
  • 基于表情符号的信息伪装算法设计与实现

    针对文本中冗余的欠缺,造成在文本中隐藏信息量少而难以实现隐密信息的传输,提出了一种基于聊天表情符号的信息伪装新方法,应用于网络聊天中以增加隐蔽性.该方法简单实用、可操作性强,实验证明,该算法具有良好的不可见性和安全性,容量也较为理想,达到信息伪装的目的.
    陈萍,孙利 - 太原理工大学学报
    文章来源: 万方数据
  • To forage or hide? Threat-sensitive foraging behaviour in wild, non-reproductive passerine birds

    Because antipredator behaviours are costly, the threat-sensitive predator avoidance hypothesis predicts that individual animals should express predator-avoidance behaviour proportionally to the perceived threat posed by the predator. Here, we experimentally tested this hypothesis by providing wild passerine birds supplemental food (on a raised feeding platform) at either 1 or 4 m from the edge of forest cover (potential refuge), in either the presence or absence of a nearby simulated predation threat (a sharp-shinned hawk Accipiter striatus model). Compared with the control treatment, we observed proportionally fewer bird visits to the food patch, and the birds took longer to re-emerge from forest refuge and return to feed at the food patch, after the hawk presentation than before it. The observed threat-sensitive latency-to-return response was stronger when the food patch was further away from the nearest refuge. Overall, our results are consistent with the predictions of the threat-sensitive predator avoidance hypothesis in that wild passerine birds (primarily black-capped chickadees Poecile atricapillus) exhibited more intense antipre- dator behavioural responses with increasing level of apparent threat. The birds were thus sensitive to their local perceived threat of predation and traded-off safety from predation (by refuging) and foraging gains in open habitat in a graded, threat-sensitive manner [Current Zoology 60 (6): 719-728, 2014].
    Shaun TURNEY,Jean-Guy J. GODIN - 动物学报(英文版)
    文章来源: 万方数据
  • 移动应用亟待加强安全监管

    2014年8月2日全国爆发的超级手机病毒,据专家分析并不属于技术性很高、隐藏性好的病毒软件,而且属于半成品.然而它通过蠕虫似的传播,在短短几小时转发病毒短信1280万余条,感染手机用户11万~12万.由此,引发了社会对移动应用软件的安全、移动终端系统的安全防护以及用户对软
    杨丰瑞,潘泉宏,许建雷 - 中国电信业
    文章来源: 万方数据
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