为了解决无电、无网络情况下井下人员逃生定位和救援导航的难题,架构了井下地磁与RFID射频结合的井下定位方法 GRPM(Geomagnetic and Radio Positioning Method)。分析了井下巷道地磁数据带状连续、区域易突变的特点,选取地磁平均值、...为了解决无电、无网络情况下井下人员逃生定位和救援导航的难题,架构了井下地磁与RFID射频结合的井下定位方法 GRPM(Geomagnetic and Radio Positioning Method)。分析了井下巷道地磁数据带状连续、区域易突变的特点,选取地磁平均值、标准差、峰态系数、粗糙度适配性指标,进行典型巷道区域的适配性评价。在适配区内开展均方差相关(MSD)、归一化积相关(NPROD),以及基于Hausdorff距离相关(HD)的定位匹配对比试验和基于等值域匹配的效果分析。试验结果表明:标准差、粗糙度指标适合巷道定位适配性评价,分析准确。基于1~2倍等值域的NPROD匹配模型适合井下人员动态行走定位,匹配速度较快,满足精确定位要求。展开更多
The uniaxial perfectly matched layer (PML) method uses rectangular domain to define the PML problem and thus provides greater flexibility and efficiency in deal- ing with problems involving anisotropic scatterers.In t...The uniaxial perfectly matched layer (PML) method uses rectangular domain to define the PML problem and thus provides greater flexibility and efficiency in deal- ing with problems involving anisotropic scatterers.In this paper an adaptive uniaxial PML technique for solving the time harmonic Helmholtz scattering problem is devel- oped.The PML parameters such as the thickness of the layer and the fictitious medium property are determined through sharp a posteriori error estimates.The adaptive finite element method based on a posteriori error estimate is proposed to solve the PML equa- tion which produces automatically a coarse mesh size away from the fixed domain and thus makes the total computational costs insensitive to the thickness of the PML absorb- ing layer.Numerical experiments are included to illustrate the competitive behavior of the proposed adaptive method.In particular,it is demonstrated that the PML layer can be chosen as close to one wave-length from the scatterer and still yields good accuracy and efficiency in approximating the far fields.展开更多
文摘为了解决无电、无网络情况下井下人员逃生定位和救援导航的难题,架构了井下地磁与RFID射频结合的井下定位方法 GRPM(Geomagnetic and Radio Positioning Method)。分析了井下巷道地磁数据带状连续、区域易突变的特点,选取地磁平均值、标准差、峰态系数、粗糙度适配性指标,进行典型巷道区域的适配性评价。在适配区内开展均方差相关(MSD)、归一化积相关(NPROD),以及基于Hausdorff距离相关(HD)的定位匹配对比试验和基于等值域匹配的效果分析。试验结果表明:标准差、粗糙度指标适合巷道定位适配性评价,分析准确。基于1~2倍等值域的NPROD匹配模型适合井下人员动态行走定位,匹配速度较快,满足精确定位要求。
文摘The uniaxial perfectly matched layer (PML) method uses rectangular domain to define the PML problem and thus provides greater flexibility and efficiency in deal- ing with problems involving anisotropic scatterers.In this paper an adaptive uniaxial PML technique for solving the time harmonic Helmholtz scattering problem is devel- oped.The PML parameters such as the thickness of the layer and the fictitious medium property are determined through sharp a posteriori error estimates.The adaptive finite element method based on a posteriori error estimate is proposed to solve the PML equa- tion which produces automatically a coarse mesh size away from the fixed domain and thus makes the total computational costs insensitive to the thickness of the PML absorb- ing layer.Numerical experiments are included to illustrate the competitive behavior of the proposed adaptive method.In particular,it is demonstrated that the PML layer can be chosen as close to one wave-length from the scatterer and still yields good accuracy and efficiency in approximating the far fields.
