The ambiguity function of Chinese standard Digital Television Terrestrial Broadcasting (DTTB) signals for passive radar contains one main peak and many side peaks. The side peaks may cause the false alarms. The relati...The ambiguity function of Chinese standard Digital Television Terrestrial Broadcasting (DTTB) signals for passive radar contains one main peak and many side peaks. The side peaks may cause the false alarms. The relative positions and the reasons for the side peaks are analyzed and a new algorithm for side peaks suppression is proposed in this paper. The algorithm, in consideration of the characteristics of the structure of the frame, can eliminate the side peaks completely in the valid Doppler observation interval by setting the reference signals to zero at equal intervals. Both the simulative and experimental results show that this algorithm can improve the performance of target detection of the passive radar based on DTTB signal.展开更多
为了提升传统行人徘徊检测方法的准确性,提出了一种结合行人检测与峰值密度聚类的行人多次徘徊检测算法(Multiple Wander Detection Combining Pedestrian Detection and Peak Density ClusteringMWD_PD_DPC)。首先,在行人检测算法的特...为了提升传统行人徘徊检测方法的准确性,提出了一种结合行人检测与峰值密度聚类的行人多次徘徊检测算法(Multiple Wander Detection Combining Pedestrian Detection and Peak Density ClusteringMWD_PD_DPC)。首先,在行人检测算法的特征提取网络与FPN层之间加入自适应卷积注意力机制(SKNet),提升模型在多尺度场景下行人检测精度。然后,提出了柔性非极大值抑制(DIOU-Soft-NMS)来缓解行人在密集场景下错误抑制的现象,提升行人检测算法在密集场景下的检测精度。最后,使用峰值密度聚类算法(DPC)对行人的轨迹进行分析,来判断是否发生徘徊行为。并通过AdaFace人脸识别算法对徘徊的行人进行人脸匹配,来判断行人是否在不同时间段多次发生徘徊行为。实验表明,该方法单次徘徊检测的准确率到达了94.6%。行人多次徘徊检测的准确率到达了78.7%。展开更多
为了研究荷电细水雾对瓦斯爆炸火焰传播速度的抑制效果及抑爆机理,基于静电感应原理,设计荷电细水雾发生及其瓦斯抑爆装置,并开展一系列荷电细水雾抑制瓦斯爆炸的实验研究。分析在不同荷电极性、荷电电压及雾通量下,荷电细水雾对爆炸火...为了研究荷电细水雾对瓦斯爆炸火焰传播速度的抑制效果及抑爆机理,基于静电感应原理,设计荷电细水雾发生及其瓦斯抑爆装置,并开展一系列荷电细水雾抑制瓦斯爆炸的实验研究。分析在不同荷电极性、荷电电压及雾通量下,荷电细水雾对爆炸火焰传播速度的影响。研究结果表明:与普通细水雾相比,荷电细水雾能更有效地降低瓦斯爆炸火焰传播速度,且随着荷电电压的增大,荷电细水雾对火焰传播速度的抑制效果显著增强;同时荷负电荷的细水雾抑爆效果比荷正电荷的细水雾更好。当细水雾加载电压为8 k V时,火焰平均传播速度下降62.12%,火焰瞬时速度下降45.67%。展开更多
文摘The ambiguity function of Chinese standard Digital Television Terrestrial Broadcasting (DTTB) signals for passive radar contains one main peak and many side peaks. The side peaks may cause the false alarms. The relative positions and the reasons for the side peaks are analyzed and a new algorithm for side peaks suppression is proposed in this paper. The algorithm, in consideration of the characteristics of the structure of the frame, can eliminate the side peaks completely in the valid Doppler observation interval by setting the reference signals to zero at equal intervals. Both the simulative and experimental results show that this algorithm can improve the performance of target detection of the passive radar based on DTTB signal.
文摘为了提升传统行人徘徊检测方法的准确性,提出了一种结合行人检测与峰值密度聚类的行人多次徘徊检测算法(Multiple Wander Detection Combining Pedestrian Detection and Peak Density ClusteringMWD_PD_DPC)。首先,在行人检测算法的特征提取网络与FPN层之间加入自适应卷积注意力机制(SKNet),提升模型在多尺度场景下行人检测精度。然后,提出了柔性非极大值抑制(DIOU-Soft-NMS)来缓解行人在密集场景下错误抑制的现象,提升行人检测算法在密集场景下的检测精度。最后,使用峰值密度聚类算法(DPC)对行人的轨迹进行分析,来判断是否发生徘徊行为。并通过AdaFace人脸识别算法对徘徊的行人进行人脸匹配,来判断行人是否在不同时间段多次发生徘徊行为。实验表明,该方法单次徘徊检测的准确率到达了94.6%。行人多次徘徊检测的准确率到达了78.7%。
文摘为了研究荷电细水雾对瓦斯爆炸火焰传播速度的抑制效果及抑爆机理,基于静电感应原理,设计荷电细水雾发生及其瓦斯抑爆装置,并开展一系列荷电细水雾抑制瓦斯爆炸的实验研究。分析在不同荷电极性、荷电电压及雾通量下,荷电细水雾对爆炸火焰传播速度的影响。研究结果表明:与普通细水雾相比,荷电细水雾能更有效地降低瓦斯爆炸火焰传播速度,且随着荷电电压的增大,荷电细水雾对火焰传播速度的抑制效果显著增强;同时荷负电荷的细水雾抑爆效果比荷正电荷的细水雾更好。当细水雾加载电压为8 k V时,火焰平均传播速度下降62.12%,火焰瞬时速度下降45.67%。
