Wavelet packet multicarrier system gains widespread concern because of its better resistance performance to Inter-Symbol Interference (ISI) and Inter-Carrier Interference (ICI), as well as the higher spectrum efficien...Wavelet packet multicarrier system gains widespread concern because of its better resistance performance to Inter-Symbol Interference (ISI) and Inter-Carrier Interference (ICI), as well as the higher spectrum efficiency. However, multicarrier system has a high Peak to Average Power Ratio (PAPR), which will lead to many problems such as lower system performance. In order to solve the problem, a kind of PAPR reduction method based on pruning Wavelet Packet Modulation (WPM) and Partial Transmit Sequences (PTS) technology is proposed in this paper, through proper pruning of the full-tree structure of wavelet packet modulation in the PTS technology to reduce the number of nodes in the system, and finally improve the reduction effect of PAPR. Simulation results show that when Complementary Cumulative Distribution Function (CCDF) is 10 -3 , PTS based on pruning WPM compared with PTS technique and pruning technique has improved about 1 dB and 1.5 dB, which will not affect the system's Bit Error Rate (BER) performance in the wavelet packet multicarrier system.展开更多
Prunusmumehas high ornamental value,and its maintenance and management should be more meticulous,with pruning being an important task.Pruning can make P.mume more robust,reduce the occurrence of diseases and pests,mai...Prunusmumehas high ornamental value,and its maintenance and management should be more meticulous,with pruning being an important task.Pruning can make P.mume more robust,reduce the occurrence of diseases and pests,maintain a good shape,and promote more flowering,further improving its ornamental value.The difficulty of pruning lies in flexibly adopting suitable pruning methods according to the time of the tree,which requires understanding the impact of pruning operations on the growth and flowering of P.mume,as well as some techniques in pruning operations.This paper introduces the botanical characteristics of P.mume,common pruning methods and achievable effects of P.mume,and suitable time for using various methods,and analyzes the possible consequences and reasons of some incorrect operations.Moreover,corresponding correct practices are provided,which can provide reference for standardized pruning of P.mume,thereby reducing or avoiding losses caused by improper operation.展开更多
针对无人机因目标较小而难以检测、检测速度慢、难于跟踪等问题,提出一种基于目标检测YOLOv5s算法和目标跟踪DeepSORT算法的无人机检测跟踪方法;采用自采数据集和公开数据集构建无人机检测数据集,使用针对小目标的数据增强方法以扩充数...针对无人机因目标较小而难以检测、检测速度慢、难于跟踪等问题,提出一种基于目标检测YOLOv5s算法和目标跟踪DeepSORT算法的无人机检测跟踪方法;采用自采数据集和公开数据集构建无人机检测数据集,使用针对小目标的数据增强方法以扩充数据集多样性;选择合适的YOLOv5算法模型实现无人机目标的精准、快速检测,引入基于批标准化层的模型剪枝方法进一步提高模型检测速度;利用DeepSORT算法实现无人机目标的实时追踪;通过对比YOLOv3、 YOLOv4、 Fast R-CNN以及改进前的YOLOv5算法,验证了本文方法在无人机检测方面的性能。结果表明:提出的无人机检测跟踪方法的全类平均精度达到0.947,每秒浮点运算次数达到2.93×10~9,在无人机检测的精度和速度方面均具有优势。展开更多
文摘Wavelet packet multicarrier system gains widespread concern because of its better resistance performance to Inter-Symbol Interference (ISI) and Inter-Carrier Interference (ICI), as well as the higher spectrum efficiency. However, multicarrier system has a high Peak to Average Power Ratio (PAPR), which will lead to many problems such as lower system performance. In order to solve the problem, a kind of PAPR reduction method based on pruning Wavelet Packet Modulation (WPM) and Partial Transmit Sequences (PTS) technology is proposed in this paper, through proper pruning of the full-tree structure of wavelet packet modulation in the PTS technology to reduce the number of nodes in the system, and finally improve the reduction effect of PAPR. Simulation results show that when Complementary Cumulative Distribution Function (CCDF) is 10 -3 , PTS based on pruning WPM compared with PTS technique and pruning technique has improved about 1 dB and 1.5 dB, which will not affect the system's Bit Error Rate (BER) performance in the wavelet packet multicarrier system.
文摘Prunusmumehas high ornamental value,and its maintenance and management should be more meticulous,with pruning being an important task.Pruning can make P.mume more robust,reduce the occurrence of diseases and pests,maintain a good shape,and promote more flowering,further improving its ornamental value.The difficulty of pruning lies in flexibly adopting suitable pruning methods according to the time of the tree,which requires understanding the impact of pruning operations on the growth and flowering of P.mume,as well as some techniques in pruning operations.This paper introduces the botanical characteristics of P.mume,common pruning methods and achievable effects of P.mume,and suitable time for using various methods,and analyzes the possible consequences and reasons of some incorrect operations.Moreover,corresponding correct practices are provided,which can provide reference for standardized pruning of P.mume,thereby reducing or avoiding losses caused by improper operation.
文摘针对无人机因目标较小而难以检测、检测速度慢、难于跟踪等问题,提出一种基于目标检测YOLOv5s算法和目标跟踪DeepSORT算法的无人机检测跟踪方法;采用自采数据集和公开数据集构建无人机检测数据集,使用针对小目标的数据增强方法以扩充数据集多样性;选择合适的YOLOv5算法模型实现无人机目标的精准、快速检测,引入基于批标准化层的模型剪枝方法进一步提高模型检测速度;利用DeepSORT算法实现无人机目标的实时追踪;通过对比YOLOv3、 YOLOv4、 Fast R-CNN以及改进前的YOLOv5算法,验证了本文方法在无人机检测方面的性能。结果表明:提出的无人机检测跟踪方法的全类平均精度达到0.947,每秒浮点运算次数达到2.93×10~9,在无人机检测的精度和速度方面均具有优势。
