随着我国城市交通的不断发展,非机动电动车的数量不断上升,绿色出行的同时,交通事故也日益增多。为了保证非机动电动车骑行人在道路上的安全,国家逐步制定法规,要求出行需佩戴头盔,各地交通部门执行检查与处罚,对骑行人佩戴头盔的自动...随着我国城市交通的不断发展,非机动电动车的数量不断上升,绿色出行的同时,交通事故也日益增多。为了保证非机动电动车骑行人在道路上的安全,国家逐步制定法规,要求出行需佩戴头盔,各地交通部门执行检查与处罚,对骑行人佩戴头盔的自动检测也提上了日程。提出用改进YOLOv5算法视频识别头盔佩戴情况,通过自组织非机动电动车骑行人头盔佩戴情况的数据集,选取聚类算法修改初始锚定框参数。然后,改进算法来适应样本集合,利用聚合输出网络提高判别的准确率。其中,采用迁移学习来减少训练资源的消耗。经各种场景实验测试的结果表明,在每秒30帧视频流下,检测的均值平均精度(mean average precision,mAP)达到了94.53%,满足对头盔佩戴检测精度和速度的要求。展开更多
The cutting burr is one of the common phenomena occurring in metal cutting.In this paper,the forming processes,main effect factors and change law of the cutting direction burr in orthogonal cutting have been studied a...The cutting burr is one of the common phenomena occurring in metal cutting.In this paper,the forming processes,main effect factors and change law of the cutting direction burr in orthogonal cutting have been studied and related theories are analyzed based on the cutting experiments.The result shows that:(1)the forming processes of cutting direction burr consist of normal cutting,flexure deformation of end surface of workpiece,plastic effect,continuous cutting and shear break separating in orthogonal cutting;(2)a new phenomenon is found that cutting direction burr is formed with the shear break separation of the chip and workpiece machined surfaces;(3)the size of cutting direction burr varies with workpiece materials,cutting parameters and geometric parameters of the cutting tool.展开更多
文摘随着我国城市交通的不断发展,非机动电动车的数量不断上升,绿色出行的同时,交通事故也日益增多。为了保证非机动电动车骑行人在道路上的安全,国家逐步制定法规,要求出行需佩戴头盔,各地交通部门执行检查与处罚,对骑行人佩戴头盔的自动检测也提上了日程。提出用改进YOLOv5算法视频识别头盔佩戴情况,通过自组织非机动电动车骑行人头盔佩戴情况的数据集,选取聚类算法修改初始锚定框参数。然后,改进算法来适应样本集合,利用聚合输出网络提高判别的准确率。其中,采用迁移学习来减少训练资源的消耗。经各种场景实验测试的结果表明,在每秒30帧视频流下,检测的均值平均精度(mean average precision,mAP)达到了94.53%,满足对头盔佩戴检测精度和速度的要求。
基金Supported by National Natural Science Foundation of China (No.59775071).
文摘The cutting burr is one of the common phenomena occurring in metal cutting.In this paper,the forming processes,main effect factors and change law of the cutting direction burr in orthogonal cutting have been studied and related theories are analyzed based on the cutting experiments.The result shows that:(1)the forming processes of cutting direction burr consist of normal cutting,flexure deformation of end surface of workpiece,plastic effect,continuous cutting and shear break separating in orthogonal cutting;(2)a new phenomenon is found that cutting direction burr is formed with the shear break separation of the chip and workpiece machined surfaces;(3)the size of cutting direction burr varies with workpiece materials,cutting parameters and geometric parameters of the cutting tool.
