Objective The western Qinling belongs to the western part of the Qinling-Dabie-Sulu orogen between the North China Block and South China Block. Multiple orogenic events might be responsible for different types of gold...Objective The western Qinling belongs to the western part of the Qinling-Dabie-Sulu orogen between the North China Block and South China Block. Multiple orogenic events might be responsible for different types of gold mineralization, making the western Qinling gold region one of the most important gold metallogenic belts in China. This region has demonstrated a total gold resource of 〉500 t and more than ten gold deposits with gold resource of 〉20 t. Almost all gold deposits in the western Qinling gold region can be classified into two distinct genetic types as orogenic （such as the Shuangwang,展开更多
A multi-objective optimization approach for the roll shifting strategy in cross rolling campaigns of hot strip mills is presented. The effect of different roll shifting strategies on roll wear contour is studied by nu...A multi-objective optimization approach for the roll shifting strategy in cross rolling campaigns of hot strip mills is presented. The effect of different roll shifting strategies on roll wear contour is studied by numerical simulation, and two evaluation indexes ,namely body smoothness and edge smoothness, are proposed. The average body smoothness and average rolling edge smoothness of all strips in a rolling campaign are taken as the objective functions, the shifting positions of all wide strips as the decision variables, and the multi-objective method of NSGA-II as the optimizer. Thus a multi-objective optimization model for the roll shifting strategy is built. The simulation results show that work roll shifting can make wear contour smooth,and a dish-shaped wear contour without severe local wear can be achieved by the roll shifting strategy with varying stroke. Optimization experimentation shows that by means of NSGA-II,a good Pareto-optimal front can be obtained, which suggests a series of alternative solutions for roll shifting strategy optimization. The experimentation also shows that there is a conflict between the two objectives. Finally, application cases confirm the feasibility of the multi-objective approach, which can improve the strip profile ,reduce edge waves and extend the rolling miles of a rolling campaign.展开更多
激光雷达在扫描周围环境时会产生部分杂乱且稀疏的点云,该类点云会在配准过程中产生过大的分布拟合误差和关联距离,进而影响配准算法的精度及同步定位与建图(simultaneous localization and mapping,SLAM)的效果。针对以上问题,提出了...激光雷达在扫描周围环境时会产生部分杂乱且稀疏的点云,该类点云会在配准过程中产生过大的分布拟合误差和关联距离,进而影响配准算法的精度及同步定位与建图(simultaneous localization and mapping,SLAM)的效果。针对以上问题,提出了一种基于分布优化配准的实时激光SLAM算法。设计了一个特征谱滤波器,该滤波器以归一化最小特征值为滤波对象,去除不符合设定分布的点云以减小分布拟合误差;提出了一个点云配准损失函数,对源点云和目标点云构成的联合协方差矩阵和误差项进行复合归一化,以减小关联距离过大的点在迭代求解过程中的干扰;设计了一个SLAM算法框架,该框架包含前端里程计、回环检测和后端优化等环节,兼容纯激光建图和激光/惯性融合建图,进而保证建图的精确性和一致性,并提高了算法的适应性。在公开数据集上进行了多组实验,实验结果表明,相较于现有SLAM算法,所提算法在精度和速度指标方面均具有较大优势。展开更多
基金financially supported by the National Natural Science Foundation of China(grants No. 41573036 and 41030423)the Xiangtanzi Gold Deposit Prospecting Program of the Zhaojin Mining Industry Company Limited(3-4-2016-061)
文摘Objective The western Qinling belongs to the western part of the Qinling-Dabie-Sulu orogen between the North China Block and South China Block. Multiple orogenic events might be responsible for different types of gold mineralization, making the western Qinling gold region one of the most important gold metallogenic belts in China. This region has demonstrated a total gold resource of 〉500 t and more than ten gold deposits with gold resource of 〉20 t. Almost all gold deposits in the western Qinling gold region can be classified into two distinct genetic types as orogenic （such as the Shuangwang,
文摘A multi-objective optimization approach for the roll shifting strategy in cross rolling campaigns of hot strip mills is presented. The effect of different roll shifting strategies on roll wear contour is studied by numerical simulation, and two evaluation indexes ,namely body smoothness and edge smoothness, are proposed. The average body smoothness and average rolling edge smoothness of all strips in a rolling campaign are taken as the objective functions, the shifting positions of all wide strips as the decision variables, and the multi-objective method of NSGA-II as the optimizer. Thus a multi-objective optimization model for the roll shifting strategy is built. The simulation results show that work roll shifting can make wear contour smooth,and a dish-shaped wear contour without severe local wear can be achieved by the roll shifting strategy with varying stroke. Optimization experimentation shows that by means of NSGA-II,a good Pareto-optimal front can be obtained, which suggests a series of alternative solutions for roll shifting strategy optimization. The experimentation also shows that there is a conflict between the two objectives. Finally, application cases confirm the feasibility of the multi-objective approach, which can improve the strip profile ,reduce edge waves and extend the rolling miles of a rolling campaign.
文摘激光雷达在扫描周围环境时会产生部分杂乱且稀疏的点云,该类点云会在配准过程中产生过大的分布拟合误差和关联距离,进而影响配准算法的精度及同步定位与建图(simultaneous localization and mapping,SLAM)的效果。针对以上问题,提出了一种基于分布优化配准的实时激光SLAM算法。设计了一个特征谱滤波器,该滤波器以归一化最小特征值为滤波对象,去除不符合设定分布的点云以减小分布拟合误差;提出了一个点云配准损失函数,对源点云和目标点云构成的联合协方差矩阵和误差项进行复合归一化,以减小关联距离过大的点在迭代求解过程中的干扰;设计了一个SLAM算法框架,该框架包含前端里程计、回环检测和后端优化等环节,兼容纯激光建图和激光/惯性融合建图,进而保证建图的精确性和一致性,并提高了算法的适应性。在公开数据集上进行了多组实验,实验结果表明,相较于现有SLAM算法,所提算法在精度和速度指标方面均具有较大优势。
