Many biodynamic models have been derived using trial and error curve-fitting technique, such that the error between the computed and measured biodynamic response functions is minimum. This study developed a biomechani...Many biodynamic models have been derived using trial and error curve-fitting technique, such that the error between the computed and measured biodynamic response functions is minimum. This study developed a biomechanical model of the human body in a sitting posture without backrest for evaluating the vibration transmissibility and dynamic response to vertical vibration direction. In describing the human body motion, a three biomechanical models are discussed (two models are 4-DOF and one model 7-DOF). Optimization software based on stochastic techniques search methods, Genetic Algorithms (GAs), is employed to determine the human model parameters imposing some limit constraints on the model parameters. In addition, an objective function is formulated comprising the sum of errors between the computed and actual values (experimental data). The studied functions are the driving-point mechanical impedance, apparent mass and seat- to-head transmissibility functions. The optimization process increased the average goodness of fit and the results of studied functions became much closer to the target values (Experimental data). From the optimized model, the resonant frequencies of the driver parts computed on the basis of biodynamic response functions are found to be within close bounds to that expected for the human body.展开更多
农村建筑物作为地震灾害中最重要的承灾对象,对其类型、分布等信息的快速获取在抗震减灾等方面具有重要意义。基于GF-2高分辨率遥感数据,利用ESP(Estimation of Scale Parameter)算法和SeaTH(Seperability and Thresholds)算法分别确定...农村建筑物作为地震灾害中最重要的承灾对象,对其类型、分布等信息的快速获取在抗震减灾等方面具有重要意义。基于GF-2高分辨率遥感数据,利用ESP(Estimation of Scale Parameter)算法和SeaTH(Seperability and Thresholds)算法分别确定影像最佳分割尺度及构建最优特征学习空间,选用决策树分类法和随机森林机器学习分类法,分别对2021年5月初甘肃省襄南镇的农村建筑物结构进行提取分类,并使用无人机航测和现场调查统计数据进行分类结果的准确度检验和修正。结果表明:①两种方法都能较好地识别空间分布均匀、面积大、颜色鲜明的砖混建筑物,但对于分布杂乱且相对集中、颜色灰暗、面积小的土木(砖木)建筑物难以有效识别出其边界轮廓并准确分类。②两种方法对研究区建筑物分类的精度分别是82.42%、86.82%,且基于随机森林的方法在提取建筑物信息时出现的错分漏分现象较少,因此,随机森林方法进行农村建筑物分类更适用。展开更多
文摘Many biodynamic models have been derived using trial and error curve-fitting technique, such that the error between the computed and measured biodynamic response functions is minimum. This study developed a biomechanical model of the human body in a sitting posture without backrest for evaluating the vibration transmissibility and dynamic response to vertical vibration direction. In describing the human body motion, a three biomechanical models are discussed (two models are 4-DOF and one model 7-DOF). Optimization software based on stochastic techniques search methods, Genetic Algorithms (GAs), is employed to determine the human model parameters imposing some limit constraints on the model parameters. In addition, an objective function is formulated comprising the sum of errors between the computed and actual values (experimental data). The studied functions are the driving-point mechanical impedance, apparent mass and seat- to-head transmissibility functions. The optimization process increased the average goodness of fit and the results of studied functions became much closer to the target values (Experimental data). From the optimized model, the resonant frequencies of the driver parts computed on the basis of biodynamic response functions are found to be within close bounds to that expected for the human body.
文摘农村建筑物作为地震灾害中最重要的承灾对象,对其类型、分布等信息的快速获取在抗震减灾等方面具有重要意义。基于GF-2高分辨率遥感数据,利用ESP(Estimation of Scale Parameter)算法和SeaTH(Seperability and Thresholds)算法分别确定影像最佳分割尺度及构建最优特征学习空间,选用决策树分类法和随机森林机器学习分类法,分别对2021年5月初甘肃省襄南镇的农村建筑物结构进行提取分类,并使用无人机航测和现场调查统计数据进行分类结果的准确度检验和修正。结果表明:①两种方法都能较好地识别空间分布均匀、面积大、颜色鲜明的砖混建筑物,但对于分布杂乱且相对集中、颜色灰暗、面积小的土木(砖木)建筑物难以有效识别出其边界轮廓并准确分类。②两种方法对研究区建筑物分类的精度分别是82.42%、86.82%,且基于随机森林的方法在提取建筑物信息时出现的错分漏分现象较少,因此,随机森林方法进行农村建筑物分类更适用。
