According to the World Health Organization,about 50 million people worldwide suffer from epilepsy.The detection and treatment of epilepsy face great challenges.Electroencephalogram(EEG)is a significant research object...According to the World Health Organization,about 50 million people worldwide suffer from epilepsy.The detection and treatment of epilepsy face great challenges.Electroencephalogram(EEG)is a significant research object widely used in diagnosis and treatment of epilepsy.In this paper,an adaptive feature learning model for EEG signals is proposed,which combines Huber loss function with adaptive weight penalty term.Firstly,each EEG signal is decomposed by intrinsic time-scale decomposition.Secondly,the statistical index values are calculated from the instantaneous amplitude and frequency of every component and fed into the proposed model.Finally,the discriminative features learned by the proposed model are used to detect seizures.Our main innovation is to consider a highly flexible penalization based on Huber loss function,which can set different weights according to the influence of different features on epilepsy detection.Besides,the new model can be solved by proximal alternating direction multiplier method,which can effectively ensure the convergence of the algorithm.The performance of the proposed method is evaluated on three public EEG datasets provided by the Bonn University,Childrens Hospital Boston-Massachusetts Institute of Technology,and Neurological and Sleep Center at Hauz Khas,New Delhi(New Delhi Epilepsy data).The recognition accuracy on these two datasets is 98%and 99.05%,respectively,indicating the application value of the new model.展开更多
为探究设施葡萄环境特征与光合速率间的相关性,实现多环境特征耦合下的设施葡萄光合速率精准预测,该研究提出一种基于灰狼算法优化BP的设施葡萄光合速率预测模型(grey wolf optimizer-back propagation,GWO-BP)。首先采集2024年6—9月...为探究设施葡萄环境特征与光合速率间的相关性,实现多环境特征耦合下的设施葡萄光合速率精准预测,该研究提出一种基于灰狼算法优化BP的设施葡萄光合速率预测模型(grey wolf optimizer-back propagation,GWO-BP)。首先采集2024年6—9月妮娜皇后葡萄光合作用数据,然后利用随机森林基尼重要性和最大信息系数筛选出影响光合速率的二氧化碳浓度、空气温度、空气湿度和光合有效辐射关键特征,构建结构为4-12-1的BP模型,使用泽维尔均匀初始化和零初始化算法分别对BP模型的权值和阈值进行初始化,并引入自适应矩估计(adaptive moment estimation,ADAM)算法动态调整学习率,最后通过灰狼算法(grey wolf optimizer,GWO)优化其初始权值和阈值。试验对比分析BP、支持向量回归(support vector regression,SVR)、随机森林(random forest,RF)、极限学习机(extreme learning machine,ELM)4种模型,确定效果最佳的基础模型,然后对比分析GWO-BP模型与基础模型。结果表明BP模型为最佳基础模型,在验证集和测试集的决定系数(R2)分别为0.832和0.834,性能优于其他3种模型;而GWO-BP模型相较于BP模型,其验证集R2提升至0.920,均方根误差下降31.2%,平均绝对误差下降25.1%;GWO-BP模型相较于BP模型,其测试集R2提升至0.918,均方根误差下降29.8%,平均绝对误差下降22.5%,Huber损失函数由0.01降低到0.006以下,有效避免BP模型易陷入局部最优的问题,灰狼算法提升BP模型的全局搜索能力和收敛稳定性,使GWO-BP模型在极端值区间的预测性能更优。该模型为准确捕捉设施葡萄光合速率与多环境特征的耦合关系,实现设施葡萄光合速率精准预测提供可靠的技术手段。展开更多
基金Supported by National Natural Science Foundation of China(Grant Nos.11701144,11971149)Henan Province Key and Promotion Special(Science and Technology)Project(Grant No.212102310305).
摘要According to the World Health Organization,about 50 million people worldwide suffer from epilepsy.The detection and treatment of epilepsy face great challenges.Electroencephalogram(EEG)is a significant research object widely used in diagnosis and treatment of epilepsy.In this paper,an adaptive feature learning model for EEG signals is proposed,which combines Huber loss function with adaptive weight penalty term.Firstly,each EEG signal is decomposed by intrinsic time-scale decomposition.Secondly,the statistical index values are calculated from the instantaneous amplitude and frequency of every component and fed into the proposed model.Finally,the discriminative features learned by the proposed model are used to detect seizures.Our main innovation is to consider a highly flexible penalization based on Huber loss function,which can set different weights according to the influence of different features on epilepsy detection.Besides,the new model can be solved by proximal alternating direction multiplier method,which can effectively ensure the convergence of the algorithm.The performance of the proposed method is evaluated on three public EEG datasets provided by the Bonn University,Childrens Hospital Boston-Massachusetts Institute of Technology,and Neurological and Sleep Center at Hauz Khas,New Delhi(New Delhi Epilepsy data).The recognition accuracy on these two datasets is 98%and 99.05%,respectively,indicating the application value of the new model.
摘要为探究设施葡萄环境特征与光合速率间的相关性,实现多环境特征耦合下的设施葡萄光合速率精准预测,该研究提出一种基于灰狼算法优化BP的设施葡萄光合速率预测模型(grey wolf optimizer-back propagation,GWO-BP)。首先采集2024年6—9月妮娜皇后葡萄光合作用数据,然后利用随机森林基尼重要性和最大信息系数筛选出影响光合速率的二氧化碳浓度、空气温度、空气湿度和光合有效辐射关键特征,构建结构为4-12-1的BP模型,使用泽维尔均匀初始化和零初始化算法分别对BP模型的权值和阈值进行初始化,并引入自适应矩估计(adaptive moment estimation,ADAM)算法动态调整学习率,最后通过灰狼算法(grey wolf optimizer,GWO)优化其初始权值和阈值。试验对比分析BP、支持向量回归(support vector regression,SVR)、随机森林(random forest,RF)、极限学习机(extreme learning machine,ELM)4种模型,确定效果最佳的基础模型,然后对比分析GWO-BP模型与基础模型。结果表明BP模型为最佳基础模型,在验证集和测试集的决定系数(R2)分别为0.832和0.834,性能优于其他3种模型;而GWO-BP模型相较于BP模型,其验证集R2提升至0.920,均方根误差下降31.2%,平均绝对误差下降25.1%;GWO-BP模型相较于BP模型,其测试集R2提升至0.918,均方根误差下降29.8%,平均绝对误差下降22.5%,Huber损失函数由0.01降低到0.006以下,有效避免BP模型易陷入局部最优的问题,灰狼算法提升BP模型的全局搜索能力和收敛稳定性,使GWO-BP模型在极端值区间的预测性能更优。该模型为准确捕捉设施葡萄光合速率与多环境特征的耦合关系,实现设施葡萄光合速率精准预测提供可靠的技术手段。
摘要为了抑制采样点中粗差对数字高程模型(digital elevation model,DEM)建模的影响,以较高精度的多面函数(multi-quadric,MQ)为基函数,由改进Huber损失函数和权重惩罚项组成目标函数,发展了MQ抗差插值算法(MQ-H)。通过优化MQ-H目标函数,采样点权重计算最终转换为方程组求解。以数学曲面为研究对象,将MQ-H计算结果与传统MQ及最小绝对偏差MQ(MQ-L)进行比较,结果表明:当采样误差服从正态分布时,MQ-H计算精度与传统MQ相当,而远高于MQ-L;当采样误差服从拉普拉斯分布时,MQ-H计算精度略高于MQ-L及传统MQ;当采样点被粗差污染时,MQ-H计算精度远高于传统MQ及MQ-L。在实例分析中,以无人遥测飞艇立体像对获取的地面离散高程点为基础数据,基于MQ-H构建测区DEM,并将计算结果与传统插值算法,如反距离加权(inverse distance weighting,IDW)、普通克里金(ordinary Kriging,OK)和专业DEM插值软件ANUDEM(Australian National University DEM)进行比较,结果表明,传统插值方法在不同程度上受采样点中异常值或偶然误差影响,而MQ-H受异常值影响较小,且能准确捕捉到地形细节信息。
摘要针对含有噪声和外点的三维点云刚体配准问题,由于迭代最近点(iterative closest point,ICP)算法的配准精度较低,为此,该文提出了一种基于改进ICP算法的三维点云刚体配准方法。考虑到伪Huber损失函数对噪声和外点不敏感、鲁棒性强,首先,建立了基于伪Huber损失函数的三维点云刚体配准模型。其次,利用RGB-D点云数据中颜色信息辅助建立点云对应关系,以提高改进ICP算法中对应点匹配的准确性。最后,结合奇异值分解(singular value decomposition,SVD)和Levenberg-Marquardt(LM)的优化算法对三维点云刚体配准模型进行优化求解。实验结果表明,该文所提三维点云刚体配准方法的配准精度高,能够有效抑制噪声和外点对配准精度的影响。