The dropping off of data during information transmission and the storage device’s damage etc.often leads the sampled data to be non-uniform.The paper, based on the stability theory of irregular wavelet frame and the ...The dropping off of data during information transmission and the storage device’s damage etc.often leads the sampled data to be non-uniform.The paper, based on the stability theory of irregular wavelet frame and the irregular weighted wavelet frame operator,proposed an irregular weighted wavelet fame conjugate gradient iterative algorithm for the reconstruction of non-uniformly sampling signal. Compared the experiment results with the iterative algorithm of the Ref.[5],the new algorithm has remarkable advantages in approximation error,running time and so on.展开更多
Aiming at the problem of video key frame extraction, a density peak clustering algorithm is proposed, which uses the HSV histogram to transform high-dimensional abstract video image data into quantifiable low-dimensio...Aiming at the problem of video key frame extraction, a density peak clustering algorithm is proposed, which uses the HSV histogram to transform high-dimensional abstract video image data into quantifiable low-dimensional data, and reduces the computational complexity while capturing image features. On this basis, the density peak clustering algorithm is used to cluster these low-dimensional data and find the cluster centers. Combining the clustering results, the final key frames are obtained. A large number of key frame extraction experiments for different types of videos show that the algorithm can extract different number of key frames by combining video content, overcome the shortcoming of traditional key frame extraction algorithm which can only extract a fixed number of key frames, and the extracted key frames can represent the main content of video accurately.展开更多
In order toovercomethe poor local search ability of genetic algorithm, resulting in the basic genetic algorithm is time-consuming, and low search abilityin the late evolutionary, we use thegray coding instead ofbinary...In order toovercomethe poor local search ability of genetic algorithm, resulting in the basic genetic algorithm is time-consuming, and low search abilityin the late evolutionary, we use thegray coding instead ofbinary codingatthebeginning of the coding;we use multi-point crossoverto replace the originalsingle-point crossoveroperation.Finally, theexperimentshows that the improved genetic algorithmnot only has a strong search capability, but also thestability has been effectively improved.展开更多
在雷达目标跟踪领域,当目标与雷达传感器存在相对运动时,多普勒(Doppler)效应致使接收信号产生频率偏移。这种频率变化与目标距离测量存在耦合关系,即多普勒距离耦合问题。在相控阵雷达采用线性调频(Linear Frequency Modulation,LFM)...在雷达目标跟踪领域,当目标与雷达传感器存在相对运动时,多普勒(Doppler)效应致使接收信号产生频率偏移。这种频率变化与目标距离测量存在耦合关系,即多普勒距离耦合问题。在相控阵雷达采用线性调频(Linear Frequency Modulation,LFM)信号进行常规跟踪时,虽然能获取大时宽带宽积提升距离分辨率,但脉冲压缩后产生的强距离多普勒耦合效应使传统的距离速度测量算法出现收敛速度慢、精度低的问题,尤其在航迹起始阶段对高速目标的跟踪极为不利,严重影响了雷达系统对目标的实时、精准监测。提出一种多普勒距离耦合下的三帧快速收敛算法。该算法利用3帧具有不同耦合系数的波形,构建多元约束方程,通过联合解算实现多目标速度和位置参数的同步获取。在验证处理流程中,采用迭代优化机制,对测量结果进行动态校准,有效降低距离与速度参数间的相互干扰,逐步逼近最优的距离和速度测量结果,从而实现快速、精准的目标跟踪。通过理论分析、蒙特卡罗仿真和外场实测数据验证,该三帧快速收敛算法展现出优异性能。在航迹起始阶段,对目标距离和速度测量解算的收敛速度是传统算法的4倍以上。所提出的多普勒距离耦合下的三帧快速收敛算法成功地解决了传统算法在处理多普勒距离耦合问题时存在的收敛慢、精度低等难题。该算法具有创新的波形设计和迭代优化策略,显著提升了相控阵雷达在复杂条件下的目标跟踪性能,为雷达目标跟踪技术的发展提供了新的思路和方法,具有较高的理论价值和实际应用前景。展开更多
Security mechanism detection is not only an important content of vulnerabilities evaluation but also the foundation of key strength test for wireless local area network （WLAN）. This paper analyzes the specifications...Security mechanism detection is not only an important content of vulnerabilities evaluation but also the foundation of key strength test for wireless local area network （WLAN）. This paper analyzes the specifications of WLAN security mechanisms and points out the defects in design of security mechanisms detection algorithm based on the standards. By capturing and analyzing a large number of Beacon frames from different vendor＇s access points （APs）, we summarize the relevant fields and information elements in a Beacon frame, and present their values or status when an AP is set to every specific security mechanism. A detection algorithm of WLAN security mechanisms is proposed based on the experimental study result and the pseudo code of a reference implementation for the algorithm is designed. The validity of the algorithm is illustrated by examples, which shows it can detect every WLAN security mechanism accurately.展开更多
针对在实际场景中,人体与背景之间存在相似的颜色和纹理,且人体运动涉及姿态的多样性,在其复杂多变的背景下运动,使分割出人体轨迹较为困难的问题,提出对称差分算法下人体运动轨迹图像分割技术。采用七帧对称差分算法提取人体运动图像...针对在实际场景中,人体与背景之间存在相似的颜色和纹理,且人体运动涉及姿态的多样性,在其复杂多变的背景下运动,使分割出人体轨迹较为困难的问题,提出对称差分算法下人体运动轨迹图像分割技术。采用七帧对称差分算法提取人体运动图像序列的前3帧和后3帧图像,计算其绝对差分图像,获取人体运动目标区域;采用非参数的统计迭代(Mean Shift)算法提取像素模值点分布情况,生成超像素,利用非参数贝叶斯聚类模型融合超像素提取人体运动目标轮廓;利用高斯混合模型建立人体运动轨迹模型,采用极限学习机求解模型识别人体运动轨迹,实现人体运动轨迹图像分割。实验结果表明,所提方法IOU(Intersection Over Union)值最高可达97%,提取运动目标区域和识别运动轨迹精度较高、分割性能较好,适用于人体运动轨迹图像分割。展开更多
基金supported by Hunan Education Office Foundation under Grant 06C260
文摘The dropping off of data during information transmission and the storage device’s damage etc.often leads the sampled data to be non-uniform.The paper, based on the stability theory of irregular wavelet frame and the irregular weighted wavelet frame operator,proposed an irregular weighted wavelet fame conjugate gradient iterative algorithm for the reconstruction of non-uniformly sampling signal. Compared the experiment results with the iterative algorithm of the Ref.[5],the new algorithm has remarkable advantages in approximation error,running time and so on.
文摘Aiming at the problem of video key frame extraction, a density peak clustering algorithm is proposed, which uses the HSV histogram to transform high-dimensional abstract video image data into quantifiable low-dimensional data, and reduces the computational complexity while capturing image features. On this basis, the density peak clustering algorithm is used to cluster these low-dimensional data and find the cluster centers. Combining the clustering results, the final key frames are obtained. A large number of key frame extraction experiments for different types of videos show that the algorithm can extract different number of key frames by combining video content, overcome the shortcoming of traditional key frame extraction algorithm which can only extract a fixed number of key frames, and the extracted key frames can represent the main content of video accurately.
文摘In order toovercomethe poor local search ability of genetic algorithm, resulting in the basic genetic algorithm is time-consuming, and low search abilityin the late evolutionary, we use thegray coding instead ofbinary codingatthebeginning of the coding;we use multi-point crossoverto replace the originalsingle-point crossoveroperation.Finally, theexperimentshows that the improved genetic algorithmnot only has a strong search capability, but also thestability has been effectively improved.
文摘在雷达目标跟踪领域,当目标与雷达传感器存在相对运动时,多普勒(Doppler)效应致使接收信号产生频率偏移。这种频率变化与目标距离测量存在耦合关系,即多普勒距离耦合问题。在相控阵雷达采用线性调频(Linear Frequency Modulation,LFM)信号进行常规跟踪时,虽然能获取大时宽带宽积提升距离分辨率,但脉冲压缩后产生的强距离多普勒耦合效应使传统的距离速度测量算法出现收敛速度慢、精度低的问题,尤其在航迹起始阶段对高速目标的跟踪极为不利,严重影响了雷达系统对目标的实时、精准监测。提出一种多普勒距离耦合下的三帧快速收敛算法。该算法利用3帧具有不同耦合系数的波形,构建多元约束方程,通过联合解算实现多目标速度和位置参数的同步获取。在验证处理流程中,采用迭代优化机制,对测量结果进行动态校准,有效降低距离与速度参数间的相互干扰,逐步逼近最优的距离和速度测量结果,从而实现快速、精准的目标跟踪。通过理论分析、蒙特卡罗仿真和外场实测数据验证,该三帧快速收敛算法展现出优异性能。在航迹起始阶段,对目标距离和速度测量解算的收敛速度是传统算法的4倍以上。所提出的多普勒距离耦合下的三帧快速收敛算法成功地解决了传统算法在处理多普勒距离耦合问题时存在的收敛慢、精度低等难题。该算法具有创新的波形设计和迭代优化策略,显著提升了相控阵雷达在复杂条件下的目标跟踪性能,为雷达目标跟踪技术的发展提供了新的思路和方法,具有较高的理论价值和实际应用前景。
基金Supported by the National Natural Science Foundation of China(51377122)
文摘Security mechanism detection is not only an important content of vulnerabilities evaluation but also the foundation of key strength test for wireless local area network （WLAN）. This paper analyzes the specifications of WLAN security mechanisms and points out the defects in design of security mechanisms detection algorithm based on the standards. By capturing and analyzing a large number of Beacon frames from different vendor＇s access points （APs）, we summarize the relevant fields and information elements in a Beacon frame, and present their values or status when an AP is set to every specific security mechanism. A detection algorithm of WLAN security mechanisms is proposed based on the experimental study result and the pseudo code of a reference implementation for the algorithm is designed. The validity of the algorithm is illustrated by examples, which shows it can detect every WLAN security mechanism accurately.
文摘针对在实际场景中,人体与背景之间存在相似的颜色和纹理,且人体运动涉及姿态的多样性,在其复杂多变的背景下运动,使分割出人体轨迹较为困难的问题,提出对称差分算法下人体运动轨迹图像分割技术。采用七帧对称差分算法提取人体运动图像序列的前3帧和后3帧图像,计算其绝对差分图像,获取人体运动目标区域;采用非参数的统计迭代(Mean Shift)算法提取像素模值点分布情况,生成超像素,利用非参数贝叶斯聚类模型融合超像素提取人体运动目标轮廓;利用高斯混合模型建立人体运动轨迹模型,采用极限学习机求解模型识别人体运动轨迹,实现人体运动轨迹图像分割。实验结果表明,所提方法IOU(Intersection Over Union)值最高可达97%,提取运动目标区域和识别运动轨迹精度较高、分割性能较好,适用于人体运动轨迹图像分割。
