The problem of the unmanned surface vessel (USV) path planning in static and dynamic obstacle environments is addressed in this paper. Multi-behavior fusion based potential field method is proposed, which contains thr...The problem of the unmanned surface vessel (USV) path planning in static and dynamic obstacle environments is addressed in this paper. Multi-behavior fusion based potential field method is proposed, which contains three behaviors: goal-seeking, boundary-memory following and dynamic-obstacle avoidance. Then, different activation conditions are designed to determine the current behavior. Meanwhile, information on the positions, velocities and the equation of motion for obstacles are detected and calculated by sensor data. Besides, memory information is introduced into the boundary following behavior to enhance cognition capability for the obstacles, and avoid local minima problem caused by the potential field method. Finally, the results of theoretical analysis and simulation show that the collision-free path can be generated for USV within different obstacle environments, and further validated the performance and effectiveness of the presented strategy.展开更多
为解决在光线昏暗、声音与视觉噪声干扰等复杂条件下,单模态鱼类行为识别准确率和召回率低的问题,提出了基于声音和视觉特征多级融合的鱼类行为识别模型U-FusionNet-ResNet50+SENet,该方法采用ResNet50模型提取视觉模态特征,通过MFCC+Re...为解决在光线昏暗、声音与视觉噪声干扰等复杂条件下,单模态鱼类行为识别准确率和召回率低的问题,提出了基于声音和视觉特征多级融合的鱼类行为识别模型U-FusionNet-ResNet50+SENet,该方法采用ResNet50模型提取视觉模态特征,通过MFCC+RestNet50模型提取声音模态特征,并在此基础上设计一种U型融合架构,使不同维度的鱼类视觉和声音特征充分交互,在特征提取的各阶段实现特征融合,最后引入SENet构成关注通道信息特征融合网络,并通过对比试验,采用多模态鱼类行为的合成加噪试验数据验证算法的有效性。结果表明:U-FusionNet-ResNet50+SENet对鱼类行为识别准确率达到93.71%,F1值达到93.43%,召回率达到92.56%,与效果较好的已有模型Intermediate-feature-level deep model相比,召回率、F1值和准确率分别提升了2.35%、3.45%和3.48%。研究表明,所提出的U-FusionNet-ResNet50+SENet识别方法,可有效解决单模态鱼类行为识别准确率低的问题,提升了鱼类行为识别的整体效果,可以有效识别复杂条件下鱼类的游泳、摄食等行为,为真实生产条件下的鱼类行为识别研究提供了新思路和新方法。展开更多
A hierarchical peer-to-peer（P2P）model and a data fusion method for network security situation awareness system are proposed to improve the efficiency of distributed security behavior monitoring network.The single po...A hierarchical peer-to-peer（P2P）model and a data fusion method for network security situation awareness system are proposed to improve the efficiency of distributed security behavior monitoring network.The single point failure of data analysis nodes is avoided by this P2P model,in which a greedy data forwarding method based on node priority and link delay is devised to promote the efficiency of data analysis nodes.And the data fusion method based on repulsive theory-Dumpster/Shafer（PSORT-DS）is used to deal with the challenge of multi-source alarm information.This data fusion method debases the false alarm rate.Compared with improved Dumpster/Shafer（DS）theoretical method based on particle swarm optimization（PSO）and classical DS evidence theoretical method,the proposed model reduces false alarm rate by 3%and 7%,respectively,whereas their detection rate increases by 4%and 16%,respectively.展开更多
激光粉末床熔融(laser powder bed fusion,LPBF)成形悬垂结构的应力与变形是实现复杂金属构件高质量、高精度制造的关键问题之一。通过基体预埋应变片的方式实现了悬垂结构LPBF成形过程应变数据的实时测量。基于原位应变测量系统研究了...激光粉末床熔融(laser powder bed fusion,LPBF)成形悬垂结构的应力与变形是实现复杂金属构件高质量、高精度制造的关键问题之一。通过基体预埋应变片的方式实现了悬垂结构LPBF成形过程应变数据的实时测量。基于原位应变测量系统研究了T形悬垂结构、低角度悬垂结构(5°和10°)LPBF过程的原位应变行为。深入研究了不同悬臂长度、不同成形工艺参数对T形悬垂结构原位应变行为的影响,并进一步分析了不同悬垂角度、支撑类型对低角度悬垂结构原位应变行为的影响。结果表明,T形悬垂结构的悬空长度越长,结构的变形越大;采用激光能量梯度、棋盘扫描策略可有效降低T形悬垂结构的变形。支撑结构设计可显著影响低角度悬垂结构的应变行为和成形质量,采用H1支撑设计策略(块体支撑间距0.8 mm+锥体支撑间距0.6 mm)的成形质量最佳。上述结果可为深入理解LPBF成形悬垂结构的变形行为和调控提供有效参考。展开更多
基金financially supported by the National Natural Science Foundation of China(Grant No.51879049)DK-I Dynamic Positioning System Console Project
文摘The problem of the unmanned surface vessel (USV) path planning in static and dynamic obstacle environments is addressed in this paper. Multi-behavior fusion based potential field method is proposed, which contains three behaviors: goal-seeking, boundary-memory following and dynamic-obstacle avoidance. Then, different activation conditions are designed to determine the current behavior. Meanwhile, information on the positions, velocities and the equation of motion for obstacles are detected and calculated by sensor data. Besides, memory information is introduced into the boundary following behavior to enhance cognition capability for the obstacles, and avoid local minima problem caused by the potential field method. Finally, the results of theoretical analysis and simulation show that the collision-free path can be generated for USV within different obstacle environments, and further validated the performance and effectiveness of the presented strategy.
文摘为解决在光线昏暗、声音与视觉噪声干扰等复杂条件下,单模态鱼类行为识别准确率和召回率低的问题,提出了基于声音和视觉特征多级融合的鱼类行为识别模型U-FusionNet-ResNet50+SENet,该方法采用ResNet50模型提取视觉模态特征,通过MFCC+RestNet50模型提取声音模态特征,并在此基础上设计一种U型融合架构,使不同维度的鱼类视觉和声音特征充分交互,在特征提取的各阶段实现特征融合,最后引入SENet构成关注通道信息特征融合网络,并通过对比试验,采用多模态鱼类行为的合成加噪试验数据验证算法的有效性。结果表明:U-FusionNet-ResNet50+SENet对鱼类行为识别准确率达到93.71%,F1值达到93.43%,召回率达到92.56%,与效果较好的已有模型Intermediate-feature-level deep model相比,召回率、F1值和准确率分别提升了2.35%、3.45%和3.48%。研究表明,所提出的U-FusionNet-ResNet50+SENet识别方法,可有效解决单模态鱼类行为识别准确率低的问题,提升了鱼类行为识别的整体效果,可以有效识别复杂条件下鱼类的游泳、摄食等行为,为真实生产条件下的鱼类行为识别研究提供了新思路和新方法。
基金Supported by the National Natural Science Foundation of China(61370212)the Research Fund for the Doctoral Program of Higher Education of China(20122304130002)+1 种基金the Natural Science Foundation of Heilongjiang Province(ZD 201102)the Fundamental Research Fund for the Central Universities(HEUCFZ1213,HEUCF100601)
文摘A hierarchical peer-to-peer（P2P）model and a data fusion method for network security situation awareness system are proposed to improve the efficiency of distributed security behavior monitoring network.The single point failure of data analysis nodes is avoided by this P2P model,in which a greedy data forwarding method based on node priority and link delay is devised to promote the efficiency of data analysis nodes.And the data fusion method based on repulsive theory-Dumpster/Shafer（PSORT-DS）is used to deal with the challenge of multi-source alarm information.This data fusion method debases the false alarm rate.Compared with improved Dumpster/Shafer（DS）theoretical method based on particle swarm optimization（PSO）and classical DS evidence theoretical method,the proposed model reduces false alarm rate by 3%and 7%,respectively,whereas their detection rate increases by 4%and 16%,respectively.
