Type WYZ 97 eighteen information noninsulate frequency shift automatic blocking system is the most advanced railroad signaling system in China nowadays.The article introduced its principles,technical targets,features ...Type WYZ 97 eighteen information noninsulate frequency shift automatic blocking system is the most advanced railroad signaling system in China nowadays.The article introduced its principles,technical targets,features and the applications.展开更多
In order to enhance the accuracy of Air Traffic Control(ATC)cybersecurity attack detection,in this paper,a new clustering detection method is designed for air traffic control network security attacks.The feature set f...In order to enhance the accuracy of Air Traffic Control(ATC)cybersecurity attack detection,in this paper,a new clustering detection method is designed for air traffic control network security attacks.The feature set for ATC cybersecurity attacks is constructed by setting the feature states,adding recursive features,and determining the feature criticality.The expected information gain and entropy of the feature data are computed to determine the information gain of the feature data and reduce the interference of similar feature data.An autoencoder is introduced into the AI(artificial intelligence)algorithm to encode and decode the characteristics of ATC network security attack behavior to reduce the dimensionality of the ATC network security attack behavior data.Based on the above processing,an unsupervised learning algorithm for clustering detection of ATC network security attacks is designed.First,determine the distance between the clustering clusters of ATC network security attack behavior characteristics,calculate the clustering threshold,and construct the initial clustering center.Then,the new average value of all feature objects in each cluster is recalculated as the new cluster center.Second,it traverses all objects in a cluster of ATC network security attack behavior feature data.Finally,the cluster detection of ATC network security attack behavior is completed by the computation of objective functions.The experiment took three groups of experimental attack behavior data sets as the test object,and took the detection rate,false detection rate and recall rate as the test indicators,and selected three similar methods for comparative test.The experimental results show that the detection rate of this method is about 98%,the false positive rate is below 1%,and the recall rate is above 97%.Research shows that this method can improve the detection performance of security attacks in air traffic control network.展开更多
为提高隐写算法的安全性,提出一种基于MME(modified matrix encoding)和IRB(iterative random blocking)的信息隐写算法。通过分析基于IRB的隐写算法流程,找到了其载密图像质量下降的主要原因,使用MME改进了该算法。实验结果表明,相比于...为提高隐写算法的安全性,提出一种基于MME(modified matrix encoding)和IRB(iterative random blocking)的信息隐写算法。通过分析基于IRB的隐写算法流程,找到了其载密图像质量下降的主要原因,使用MME改进了该算法。实验结果表明,相比于IRB隐写算法,改进算法提高了载密图像质量,同时提高了抵抗盲检测的能力。改进算法表明了使用隐写编码可提高嵌入效率,从而提高隐写算法的安全性。展开更多
针对当前加密图像可逆信息隐藏方法中存在的嵌入率低,标记图像直接解密后视觉质量差的问题,提出一种位平面分块编码的加密图像可逆信息隐藏方法。算法通过2D sine logistic混沌映射对图像分块加密,保留块内像素的相关性。将加密后的图...针对当前加密图像可逆信息隐藏方法中存在的嵌入率低,标记图像直接解密后视觉质量差的问题,提出一种位平面分块编码的加密图像可逆信息隐藏方法。算法通过2D sine logistic混沌映射对图像分块加密,保留块内像素的相关性。将加密后的图像块化分成8个位平面,在低阶位平面中,根据块平面内0元素和1元素的分布情况,进行编码压缩,利用压缩后块平面内生成冗余空间进行机密信息的嵌入,图像的其余位平面部分则保持不变。在接收端,接收者获取密钥后可以进行信息提取,图像解密和图像的无损恢复。利用标准图像库中图像进行仿真实验,结果表明:随着可嵌入低位平面数的增加,算法的嵌入容量逐渐增大,在低阶平面数取3时,该算法保持较高的嵌入率时,仍然使得直接解密后的图像仍具有较高的PSNR值。展开更多
针对高效视频编码(HEVC)帧间预测过程所引入较高的复杂度,分别提出提前决策skip模式,编码单元(CU)提前终止分割以及变换单元(TU)提前终止分割。首先,根据自然视频序列多采用skip模式,利用当前块和空间相邻块的已编码信息提前决定skip模...针对高效视频编码(HEVC)帧间预测过程所引入较高的复杂度,分别提出提前决策skip模式,编码单元(CU)提前终止分割以及变换单元(TU)提前终止分割。首先,根据自然视频序列多采用skip模式,利用当前块和空间相邻块的已编码信息提前决定skip模式;其次,为了避免编码不必要的深度,利用先前已编码块的率失真代价(rdcost)决策CU提前终止分割;最后,利用当前预测残差块的纹理复杂度决策TU的提前终止分割。实验结果表明,提出的算法最终可以节省编码时间43.78%,同时造成bj?ntegaard delta bit rate(BDBR)的损失为1.675%。通过实验数据的比较,在对视频质量的影响忽略不计的情况下,能够很大程度上减少复杂度。展开更多
闭环检测是同步定位与建图(simultaneous localization and mapping,SLAM)中的一个重要组成部分,用于减少移动机器人在位置估计和构建环境地图时产生的累计误差。传统方法采用人工设计的特征,但在外界环境中容易受到光照、天气和视点变...闭环检测是同步定位与建图(simultaneous localization and mapping,SLAM)中的一个重要组成部分,用于减少移动机器人在位置估计和构建环境地图时产生的累计误差。传统方法采用人工设计的特征,但在外界环境中容易受到光照、天气和视点变化等因素所带来的影响。随着深度学习技术的发展,闭环检测得到广泛的探索,且在复杂环境中基于深度学习的闭环检测具有较强的鲁棒性。通过梳理闭环检测的背景和发展现状,从基于深度卷积神经网络、自动编码器和语义信息三个方面,对目前视觉SLAM(visual-SLAM,V-SLAM)闭环检测方法的基本原理、算法特点进行了对比分析,并从视觉应用层面上总结了三类方法所适用的场景,最后讨论了闭环检测未来在自然环境变化、多移动目标和实时动态三个方面所存在的挑战和研究展望。展开更多
文摘Type WYZ 97 eighteen information noninsulate frequency shift automatic blocking system is the most advanced railroad signaling system in China nowadays.The article introduced its principles,technical targets,features and the applications.
基金National Natural Science Foundation of China(U2133208,U20A20161)National Natural Science Foundation of China(No.62273244)Sichuan Science and Technology Program(No.2022YFG0180).
文摘In order to enhance the accuracy of Air Traffic Control(ATC)cybersecurity attack detection,in this paper,a new clustering detection method is designed for air traffic control network security attacks.The feature set for ATC cybersecurity attacks is constructed by setting the feature states,adding recursive features,and determining the feature criticality.The expected information gain and entropy of the feature data are computed to determine the information gain of the feature data and reduce the interference of similar feature data.An autoencoder is introduced into the AI(artificial intelligence)algorithm to encode and decode the characteristics of ATC network security attack behavior to reduce the dimensionality of the ATC network security attack behavior data.Based on the above processing,an unsupervised learning algorithm for clustering detection of ATC network security attacks is designed.First,determine the distance between the clustering clusters of ATC network security attack behavior characteristics,calculate the clustering threshold,and construct the initial clustering center.Then,the new average value of all feature objects in each cluster is recalculated as the new cluster center.Second,it traverses all objects in a cluster of ATC network security attack behavior feature data.Finally,the cluster detection of ATC network security attack behavior is completed by the computation of objective functions.The experiment took three groups of experimental attack behavior data sets as the test object,and took the detection rate,false detection rate and recall rate as the test indicators,and selected three similar methods for comparative test.The experimental results show that the detection rate of this method is about 98%,the false positive rate is below 1%,and the recall rate is above 97%.Research shows that this method can improve the detection performance of security attacks in air traffic control network.
文摘为提高隐写算法的安全性,提出一种基于MME(modified matrix encoding)和IRB(iterative random blocking)的信息隐写算法。通过分析基于IRB的隐写算法流程,找到了其载密图像质量下降的主要原因,使用MME改进了该算法。实验结果表明,相比于IRB隐写算法,改进算法提高了载密图像质量,同时提高了抵抗盲检测的能力。改进算法表明了使用隐写编码可提高嵌入效率,从而提高隐写算法的安全性。
文摘针对当前加密图像可逆信息隐藏方法中存在的嵌入率低,标记图像直接解密后视觉质量差的问题,提出一种位平面分块编码的加密图像可逆信息隐藏方法。算法通过2D sine logistic混沌映射对图像分块加密,保留块内像素的相关性。将加密后的图像块化分成8个位平面,在低阶位平面中,根据块平面内0元素和1元素的分布情况,进行编码压缩,利用压缩后块平面内生成冗余空间进行机密信息的嵌入,图像的其余位平面部分则保持不变。在接收端,接收者获取密钥后可以进行信息提取,图像解密和图像的无损恢复。利用标准图像库中图像进行仿真实验,结果表明:随着可嵌入低位平面数的增加,算法的嵌入容量逐渐增大,在低阶平面数取3时,该算法保持较高的嵌入率时,仍然使得直接解密后的图像仍具有较高的PSNR值。
文摘针对高效视频编码(HEVC)帧间预测过程所引入较高的复杂度,分别提出提前决策skip模式,编码单元(CU)提前终止分割以及变换单元(TU)提前终止分割。首先,根据自然视频序列多采用skip模式,利用当前块和空间相邻块的已编码信息提前决定skip模式;其次,为了避免编码不必要的深度,利用先前已编码块的率失真代价(rdcost)决策CU提前终止分割;最后,利用当前预测残差块的纹理复杂度决策TU的提前终止分割。实验结果表明,提出的算法最终可以节省编码时间43.78%,同时造成bj?ntegaard delta bit rate(BDBR)的损失为1.675%。通过实验数据的比较,在对视频质量的影响忽略不计的情况下,能够很大程度上减少复杂度。
文摘闭环检测是同步定位与建图(simultaneous localization and mapping,SLAM)中的一个重要组成部分,用于减少移动机器人在位置估计和构建环境地图时产生的累计误差。传统方法采用人工设计的特征,但在外界环境中容易受到光照、天气和视点变化等因素所带来的影响。随着深度学习技术的发展,闭环检测得到广泛的探索,且在复杂环境中基于深度学习的闭环检测具有较强的鲁棒性。通过梳理闭环检测的背景和发展现状,从基于深度卷积神经网络、自动编码器和语义信息三个方面,对目前视觉SLAM(visual-SLAM,V-SLAM)闭环检测方法的基本原理、算法特点进行了对比分析,并从视觉应用层面上总结了三类方法所适用的场景,最后讨论了闭环检测未来在自然环境变化、多移动目标和实时动态三个方面所存在的挑战和研究展望。
