如何准确对岩体分级是深埋地下工程的一个难题。针对单一岩体评价模型存在误判的问题,提出了Random Over Sampler (ROS)改进机器学习算法集成权重岩体质量评价方法。采用ROS算法对类别非均衡样本进行采样处理,经SVM、KNN、NB、DT、RBF...如何准确对岩体分级是深埋地下工程的一个难题。针对单一岩体评价模型存在误判的问题,提出了Random Over Sampler (ROS)改进机器学习算法集成权重岩体质量评价方法。采用ROS算法对类别非均衡样本进行采样处理,经SVM、KNN、NB、DT、RBF、RF、LDA、LightGBM、XGBoost和GradientBoosting计算得到初步分级结果。将每一个分类器作为一个指标,确定每一个分类器的权重,建立ROS与机器学习算法的集成权重岩体质量评价模型,得到综合判别结果,大大降低了单一模型误判率。基于ROS改进机器学习算法集成权重提高了岩体质量评价模型的准确率,为岩体质量评价提供一种新的方法。展开更多
Lateral type n-channel 4H-SiC metal–oxide–semiconductor field effect transistors(MOSFETs),fabricated using a current industrial process,are irradiated with gamma rays at different irradiation doses in this paper to ...Lateral type n-channel 4H-SiC metal–oxide–semiconductor field effect transistors(MOSFETs),fabricated using a current industrial process,are irradiated with gamma rays at different irradiation doses in this paper to carry out a profound study on the generation mechanism of radiation-induced interface traps and oxide trapped charges.Electrical parameters(e.g.,threshold voltage,subthreshold swing and channel mobility)of the device before and after irradiation are investigated,and the influence of the channel orientation([1100]and[1120])on the radiation effect is discussed for the first time.A positive threshold voltage shift is observed at very low irradiation doses(<100 krad(Si));the threshold voltage then shifts negatively as the dose increases.It is found that the dependence of interface trap generation on the radiation dose is not the same for doses below and above 100 krad.For irradiation doses<100 krad,the radiation-induced interface traps with relatively high generation speeds dominate the competition with radiation-induced oxide trapped charges,contributing to the positive threshold voltage shift correspondingly.All these results provide additional insight into the radiation-induced charge trapping mechanism in the SiO_(2)/SiC interface.展开更多
文摘如何准确对岩体分级是深埋地下工程的一个难题。针对单一岩体评价模型存在误判的问题,提出了Random Over Sampler (ROS)改进机器学习算法集成权重岩体质量评价方法。采用ROS算法对类别非均衡样本进行采样处理,经SVM、KNN、NB、DT、RBF、RF、LDA、LightGBM、XGBoost和GradientBoosting计算得到初步分级结果。将每一个分类器作为一个指标,确定每一个分类器的权重,建立ROS与机器学习算法的集成权重岩体质量评价模型,得到综合判别结果,大大降低了单一模型误判率。基于ROS改进机器学习算法集成权重提高了岩体质量评价模型的准确率,为岩体质量评价提供一种新的方法。
基金the National Natural Science Foundation of China(Grant Nos.52107190 and 62101181)China Postdoctoral Science Foundation(Grant No.2021M700203)。
文摘Lateral type n-channel 4H-SiC metal–oxide–semiconductor field effect transistors(MOSFETs),fabricated using a current industrial process,are irradiated with gamma rays at different irradiation doses in this paper to carry out a profound study on the generation mechanism of radiation-induced interface traps and oxide trapped charges.Electrical parameters(e.g.,threshold voltage,subthreshold swing and channel mobility)of the device before and after irradiation are investigated,and the influence of the channel orientation([1100]and[1120])on the radiation effect is discussed for the first time.A positive threshold voltage shift is observed at very low irradiation doses(<100 krad(Si));the threshold voltage then shifts negatively as the dose increases.It is found that the dependence of interface trap generation on the radiation dose is not the same for doses below and above 100 krad.For irradiation doses<100 krad,the radiation-induced interface traps with relatively high generation speeds dominate the competition with radiation-induced oxide trapped charges,contributing to the positive threshold voltage shift correspondingly.All these results provide additional insight into the radiation-induced charge trapping mechanism in the SiO_(2)/SiC interface.
