The quality of hot-rolled steel strip is directly affected by the strip crown.Traditional machine learning models have shown limitations in accurately predicting the strip crown,particularly when dealing with imbalanc...The quality of hot-rolled steel strip is directly affected by the strip crown.Traditional machine learning models have shown limitations in accurately predicting the strip crown,particularly when dealing with imbalanced data.This limitation results in poor production quality and efficiency,leading to increased production costs.Thus,a novel strip crown prediction model that uses the Boruta and extremely randomized trees(Boruta-ERT)algorithms to address this issue was proposed.To improve the accuracy of our model,we utilized the synthetic minority over-sampling technique to balance the imbalance data sets.The Boruta-ERT prediction model was then used to select features and predict the strip crown.With the 2160 mm hot rolling production lines of a steel plant serving as the research object,the experimental results showed that 97.01% of prediction data have an absolute error of less than 8 lm.This level of accuracy met the control requirements for strip crown and demonstrated significant benefits for the improvement in production quality of steel strip.展开更多
森林生态系统作为陆地上最大的碳汇,其碳储量估算的准确性直接影响碳循环模型构建及碳中和政策制定,传统的森林碳储量动态估测主要基于林分尺度,难以反映单株树木的碳储量变化。该研究以12块不同株行距配置和无性系的杨树人工林为研究对...森林生态系统作为陆地上最大的碳汇,其碳储量估算的准确性直接影响碳循环模型构建及碳中和政策制定,传统的森林碳储量动态估测主要基于林分尺度,难以反映单株树木的碳储量变化。该研究以12块不同株行距配置和无性系的杨树人工林为研究对象,基于2019年和2021年的地基激光雷达(terrestrial laser scanning,TLS)数据利用非完全模拟树木水分养分传输的骨架提取算法(a novel algorithm of the incomplete simulation of tree transmitting water and nutrients,ISTTWN)提取多项基本测树因子,经相关性与共线性分析、Boruta算法实现变量筛选后构建线性和非线性以及4种机器学习模型(随机森林、K最近邻、支持向量机、CatBoost)经Optuna框架参数调优后选取最佳模型,通过直接与间接的方法估测单木地上碳储量增量,探究研究区杨树的最优单木地上碳储量增量估测方法以及最佳种植配置。结果表明,基于Boruta算法筛选变量的随机森林模型在研究区杨树单木地上碳储量(R2=0.944)以及碳储量增量(R2=0.798)的估测中展现出优势;以单木地上碳储量增量为因变量构建随机森林模型的直接法是研究区内杨树单木地上碳储量增量的较优估测方案(R2为0.821,均方根误差为0.920 kg和平均绝对误差为0.733 kg);研究期内,株行距配置为6 m×6 m的‘南林797杨’单木地上碳储量增量最大,单木地上碳储量增长率也处于较高水平,表明该配置比较有利于杨树的碳积累。该研究提供了一种估算单株杨树地上碳储量增量的非破坏性方法,对优化碳导向型杨树人工林的管理具有一定参考意义。展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.52074085,U21A20117 and U21A20475)the Fundamental Research Funds for the Central Universities(Grant No.N2004010)the Liaoning Revitalization Talents Program(XLYC1907065).
摘要The quality of hot-rolled steel strip is directly affected by the strip crown.Traditional machine learning models have shown limitations in accurately predicting the strip crown,particularly when dealing with imbalanced data.This limitation results in poor production quality and efficiency,leading to increased production costs.Thus,a novel strip crown prediction model that uses the Boruta and extremely randomized trees(Boruta-ERT)algorithms to address this issue was proposed.To improve the accuracy of our model,we utilized the synthetic minority over-sampling technique to balance the imbalance data sets.The Boruta-ERT prediction model was then used to select features and predict the strip crown.With the 2160 mm hot rolling production lines of a steel plant serving as the research object,the experimental results showed that 97.01% of prediction data have an absolute error of less than 8 lm.This level of accuracy met the control requirements for strip crown and demonstrated significant benefits for the improvement in production quality of steel strip.
摘要森林生态系统作为陆地上最大的碳汇,其碳储量估算的准确性直接影响碳循环模型构建及碳中和政策制定,传统的森林碳储量动态估测主要基于林分尺度,难以反映单株树木的碳储量变化。该研究以12块不同株行距配置和无性系的杨树人工林为研究对象,基于2019年和2021年的地基激光雷达(terrestrial laser scanning,TLS)数据利用非完全模拟树木水分养分传输的骨架提取算法(a novel algorithm of the incomplete simulation of tree transmitting water and nutrients,ISTTWN)提取多项基本测树因子,经相关性与共线性分析、Boruta算法实现变量筛选后构建线性和非线性以及4种机器学习模型(随机森林、K最近邻、支持向量机、CatBoost)经Optuna框架参数调优后选取最佳模型,通过直接与间接的方法估测单木地上碳储量增量,探究研究区杨树的最优单木地上碳储量增量估测方法以及最佳种植配置。结果表明,基于Boruta算法筛选变量的随机森林模型在研究区杨树单木地上碳储量(R2=0.944)以及碳储量增量(R2=0.798)的估测中展现出优势;以单木地上碳储量增量为因变量构建随机森林模型的直接法是研究区内杨树单木地上碳储量增量的较优估测方案(R2为0.821,均方根误差为0.920 kg和平均绝对误差为0.733 kg);研究期内,株行距配置为6 m×6 m的‘南林797杨’单木地上碳储量增量最大,单木地上碳储量增长率也处于较高水平,表明该配置比较有利于杨树的碳积累。该研究提供了一种估算单株杨树地上碳储量增量的非破坏性方法,对优化碳导向型杨树人工林的管理具有一定参考意义。