In this paper, we applied the rough sets to the point cluster and river network selection. In order to meet the requirements of rough sets, first, we structuralize and quantify the spatial information of objects by co...In this paper, we applied the rough sets to the point cluster and river network selection. In order to meet the requirements of rough sets, first, we structuralize and quantify the spatial information of objects by convex hull, triangulated irregular network (TIN), Voronoi diagram, etc.;second, we manually assign decisional attributes to the information table according to conditional attributes. In doing so, the spatial information and attribute information are integrated together to evaluate the importance of points and rivers by rough sets theory. Finally, we select the point cluster and the river network in a progressive manner. The experimental results show that our method is valid and effective. In comparison with previous work, our method has the advantage to adaptively consider the spatial and attribute information at the same time without any a priori knowledge.展开更多
Reduced order models(ROMs) based on the snapshots on the CFD high-fidelity simulations have been paid great attention recently due to their capability of capturing the features of the complex geometries and flow confi...Reduced order models(ROMs) based on the snapshots on the CFD high-fidelity simulations have been paid great attention recently due to their capability of capturing the features of the complex geometries and flow configurations. To improve the efficiency and precision of the ROMs, it is indispensable to add extra sampling points to the initial snapshots, since the number of sampling points to achieve an adequately accurate ROM is generally unknown in prior, but a large number of initial sampling points reduces the parsimony of the ROMs. A fuzzy-clustering-based adding-point strategy is proposed and the fuzzy clustering acts an indicator of the region in which the precision of ROMs is relatively low. The proposed method is applied to construct the ROMs for the benchmark mathematical examples and a numerical example of hypersonic aerothermodynamics prediction for a typical control surface. The proposed method can achieve a 34.5% improvement on the efficiency than the estimated mean squared error prediction algorithm and shows same-level prediction accuracy.展开更多
为减少因船舶偏离航道而造成的搁浅、碰撞航标或桥墩等水上交通事故,提出了一种基于多目相机自动识别航道的桥区航行异常船舶预警方法。基于YOLOv5(You Only Look Once version 5)目标检测算法,联动变、定焦相机识别并定位航标和船舶,...为减少因船舶偏离航道而造成的搁浅、碰撞航标或桥墩等水上交通事故,提出了一种基于多目相机自动识别航道的桥区航行异常船舶预警方法。基于YOLOv5(You Only Look Once version 5)目标检测算法,联动变、定焦相机识别并定位航标和船舶,跟踪并记录船舶航迹点,计算船舶的速度和航向并推算船位。提出了一种基于视频船舶航迹点的密度聚类识别航道两侧航标的方法,实现航道自适应可视化。基于船位推算识别并预警航行状态异常的船舶。实验结果表明:航标、船舶的检测正确率分别达84.8%、90.3%,相较单一相机检测模型,正确率分别提高了32.1%、5.5%;能够自适应可视化航道并识别、预警航行异常船舶。展开更多
道路点云数据的障碍物检测技术在智能交通系统和自动驾驶中至关重要.传统的基于密度的空间聚类(DensityBased Spatial Clustering of Applications with Noise,DBSCAN)算法在处理高维或不同密度区域数据时,由于距离度量低效、参数组合...道路点云数据的障碍物检测技术在智能交通系统和自动驾驶中至关重要.传统的基于密度的空间聚类(DensityBased Spatial Clustering of Applications with Noise,DBSCAN)算法在处理高维或不同密度区域数据时,由于距离度量低效、参数组合确定困难导致聚类效果欠佳,因此,提出了一种基于改进DBSCAN的道路障碍物点云聚类方法 .首先,在确定Eps领域时利用孤立核函数来改进传统的距离度量方式,提高了DBSCAN聚类对不同密度区域的适应性和准确性.其次,针对猎豹优化算法(Cheetah Optimizer,CO)在信息共享和迭代更新方面的不足,提出了一种基于及时更新机制与兼容度量策略的CO优化算法(Timely Updating Mechanisms and Compatible Metric Strategies for CO Algorithms,TCCO),通过实时更新操作确保每次迭代的优秀信息得到及时沟通共享,并在全局更新时基于非支配排序与拥挤距离优化淘汰机制,平衡全局搜索和局部开发能力,提高了收敛速度和收敛精度.最后,利用孤立度量改进Eps领域,并利用TCCO优化DBSCAN聚类,自适应确定参数,提高了聚类精度和效率.在八个UCI数据集上进行测试,仿真结果表明,提出的TCCO-DBSCAN算法与CO-DBSCAN,SSA-DBSCAN,DBSCAN,KMC方法相比,F-Measure,ARI,NMI指标均有明显提升,且聚类精度更优.通过激光雷达点云数据障碍物聚类的实验验证,证明TCCO-DBSCAN能够有效地适应点云数据密度变化,获得更好的道路障碍物聚类效果,为辅助驾驶中障碍物检测提供支持.展开更多
文摘In this paper, we applied the rough sets to the point cluster and river network selection. In order to meet the requirements of rough sets, first, we structuralize and quantify the spatial information of objects by convex hull, triangulated irregular network (TIN), Voronoi diagram, etc.;second, we manually assign decisional attributes to the information table according to conditional attributes. In doing so, the spatial information and attribute information are integrated together to evaluate the importance of points and rivers by rough sets theory. Finally, we select the point cluster and the river network in a progressive manner. The experimental results show that our method is valid and effective. In comparison with previous work, our method has the advantage to adaptively consider the spatial and attribute information at the same time without any a priori knowledge.
基金Supported by National Natural Science Foundation of China(Grant No.11372036)
文摘Reduced order models(ROMs) based on the snapshots on the CFD high-fidelity simulations have been paid great attention recently due to their capability of capturing the features of the complex geometries and flow configurations. To improve the efficiency and precision of the ROMs, it is indispensable to add extra sampling points to the initial snapshots, since the number of sampling points to achieve an adequately accurate ROM is generally unknown in prior, but a large number of initial sampling points reduces the parsimony of the ROMs. A fuzzy-clustering-based adding-point strategy is proposed and the fuzzy clustering acts an indicator of the region in which the precision of ROMs is relatively low. The proposed method is applied to construct the ROMs for the benchmark mathematical examples and a numerical example of hypersonic aerothermodynamics prediction for a typical control surface. The proposed method can achieve a 34.5% improvement on the efficiency than the estimated mean squared error prediction algorithm and shows same-level prediction accuracy.
文摘为减少因船舶偏离航道而造成的搁浅、碰撞航标或桥墩等水上交通事故,提出了一种基于多目相机自动识别航道的桥区航行异常船舶预警方法。基于YOLOv5(You Only Look Once version 5)目标检测算法,联动变、定焦相机识别并定位航标和船舶,跟踪并记录船舶航迹点,计算船舶的速度和航向并推算船位。提出了一种基于视频船舶航迹点的密度聚类识别航道两侧航标的方法,实现航道自适应可视化。基于船位推算识别并预警航行状态异常的船舶。实验结果表明:航标、船舶的检测正确率分别达84.8%、90.3%,相较单一相机检测模型,正确率分别提高了32.1%、5.5%;能够自适应可视化航道并识别、预警航行异常船舶。
文摘道路点云数据的障碍物检测技术在智能交通系统和自动驾驶中至关重要.传统的基于密度的空间聚类(DensityBased Spatial Clustering of Applications with Noise,DBSCAN)算法在处理高维或不同密度区域数据时,由于距离度量低效、参数组合确定困难导致聚类效果欠佳,因此,提出了一种基于改进DBSCAN的道路障碍物点云聚类方法 .首先,在确定Eps领域时利用孤立核函数来改进传统的距离度量方式,提高了DBSCAN聚类对不同密度区域的适应性和准确性.其次,针对猎豹优化算法(Cheetah Optimizer,CO)在信息共享和迭代更新方面的不足,提出了一种基于及时更新机制与兼容度量策略的CO优化算法(Timely Updating Mechanisms and Compatible Metric Strategies for CO Algorithms,TCCO),通过实时更新操作确保每次迭代的优秀信息得到及时沟通共享,并在全局更新时基于非支配排序与拥挤距离优化淘汰机制,平衡全局搜索和局部开发能力,提高了收敛速度和收敛精度.最后,利用孤立度量改进Eps领域,并利用TCCO优化DBSCAN聚类,自适应确定参数,提高了聚类精度和效率.在八个UCI数据集上进行测试,仿真结果表明,提出的TCCO-DBSCAN算法与CO-DBSCAN,SSA-DBSCAN,DBSCAN,KMC方法相比,F-Measure,ARI,NMI指标均有明显提升,且聚类精度更优.通过激光雷达点云数据障碍物聚类的实验验证,证明TCCO-DBSCAN能够有效地适应点云数据密度变化,获得更好的道路障碍物聚类效果,为辅助驾驶中障碍物检测提供支持.
