汉源县滑坡地质灾害频发,对于未来不同气候情景下的滑坡地质灾害易发性情况的预测研究,可为未来气候变化下的防灾减灾工作提供参考依据。文中基于EC-Earth3模式下的3种未来不同气候情景(SSP1-2.6、SSP2-4.5、SSP5-8.5)数据,在Pearson相...汉源县滑坡地质灾害频发,对于未来不同气候情景下的滑坡地质灾害易发性情况的预测研究,可为未来气候变化下的防灾减灾工作提供参考依据。文中基于EC-Earth3模式下的3种未来不同气候情景(SSP1-2.6、SSP2-4.5、SSP5-8.5)数据,在Pearson相关性分析与多重共线性分析的基础上,最终选取坡度、坡向、剖面曲率、地形湿度、土地利用、距断层距离、降雨量和径流量共8个影响因子作为滑坡易发性评估指标,采用信息量-熵指数模型与支持向量机模型开展不同气候情景下滑坡易发性评估。结果表明:在SSP1-2.6、SSP2-4.5以及SSP5-8.5情景下,信息量-熵指数模型的曲线下面积(area under curve,AUC)值均为0.928,在SSP1-2.6、SSP2-4.5以及SSP5-8.5情景下,支持向量机模型的AUC值分别为0.957、0.967、0.969。支持向量机模型在未来不同气候情景下的滑坡易发性预测精度方面具有更强的鲁棒性,在SSP1-2.6、SSP2-4.5以及SSP5-8.5情景下发生滑坡灾害的区域面积分别为23.02%、21.09%、26.39%,表明在高排放、高发展的情景下,滑坡灾害发生的可能性将会更大。展开更多
An optimized detection model based on weighted entropy for multiple input multiple output (MIMO) radar in multipath environment is presented. After defining the multipath distance difference (MDD), the multipath recei...An optimized detection model based on weighted entropy for multiple input multiple output (MIMO) radar in multipath environment is presented. After defining the multipath distance difference (MDD), the multipath received signal model with four paths is built systematically. Both the variance and correlation coefficient of multipath scattering coefficient with MDD are analyzed, which indicates that the multipath variable can decrease the detection performance by reducing the echo power. By making use of the likelihood ratio test (LRT), a new method based on weighted entropy is introduced to use the positive multipath echo power and suppress the negative echo power, which results in better performance. Simulation results show that, compared with non-multipath environment or other recently developed methods, the proposed method can achieve detection performance improvement with the increase of sensors.展开更多
Thermal transport in porous media has stimulated substantial interest in engineering sciences due to increasing applications in filtration systems,porous bearings,porous layer insulation,biomechanics,geomechanics etc....Thermal transport in porous media has stimulated substantial interest in engineering sciences due to increasing applications in filtration systems,porous bearings,porous layer insulation,biomechanics,geomechanics etc.Motivated by such applications,in this article,a numerical study of entropy generation impacts on the heat and momentum transfer in time-dependent laminar incompressible boundary layer flow of a Casson viscoplastic fluid over a uniformly heated vertical cylinder embedded in a porous medium is presented.Darcy’s law is used to simulate bulk drag effects at low Reynolds number for an isotropic,homogenous porous medium.Heat line visualization is also included.The mathematical model is derived and normalized using appropriate transformation variables.The resulting non-linear time-dependent coupled governing equations with associated boundary conditions are solved via an implicit finite difference method which is efficient and unconditionally stable.The outcomes show that entropy generation and Bejan number are both elevated with increasing values of Darcy number,Casson fluid parameter,group parameter and Grashof number.To analyze the heat transfer process in a two-dimensional domain,plotting heat lines provides an excellent approach in addition to streamlines and isotherms.It is remarked that as the Darcy number increases,the deviations of heat lines from the hot wall are reduced.展开更多
文摘汉源县滑坡地质灾害频发,对于未来不同气候情景下的滑坡地质灾害易发性情况的预测研究,可为未来气候变化下的防灾减灾工作提供参考依据。文中基于EC-Earth3模式下的3种未来不同气候情景(SSP1-2.6、SSP2-4.5、SSP5-8.5)数据,在Pearson相关性分析与多重共线性分析的基础上,最终选取坡度、坡向、剖面曲率、地形湿度、土地利用、距断层距离、降雨量和径流量共8个影响因子作为滑坡易发性评估指标,采用信息量-熵指数模型与支持向量机模型开展不同气候情景下滑坡易发性评估。结果表明:在SSP1-2.6、SSP2-4.5以及SSP5-8.5情景下,信息量-熵指数模型的曲线下面积(area under curve,AUC)值均为0.928,在SSP1-2.6、SSP2-4.5以及SSP5-8.5情景下,支持向量机模型的AUC值分别为0.957、0.967、0.969。支持向量机模型在未来不同气候情景下的滑坡易发性预测精度方面具有更强的鲁棒性,在SSP1-2.6、SSP2-4.5以及SSP5-8.5情景下发生滑坡灾害的区域面积分别为23.02%、21.09%、26.39%,表明在高排放、高发展的情景下,滑坡灾害发生的可能性将会更大。
基金supported by the Natural Science Foundation Research Project of Shaanxi Province(2016JQ6020)
文摘An optimized detection model based on weighted entropy for multiple input multiple output (MIMO) radar in multipath environment is presented. After defining the multipath distance difference (MDD), the multipath received signal model with four paths is built systematically. Both the variance and correlation coefficient of multipath scattering coefficient with MDD are analyzed, which indicates that the multipath variable can decrease the detection performance by reducing the echo power. By making use of the likelihood ratio test (LRT), a new method based on weighted entropy is introduced to use the positive multipath echo power and suppress the negative echo power, which results in better performance. Simulation results show that, compared with non-multipath environment or other recently developed methods, the proposed method can achieve detection performance improvement with the increase of sensors.
基金DST-INSPIRE (Code No. IF160028) for the grant of research fellowship
文摘Thermal transport in porous media has stimulated substantial interest in engineering sciences due to increasing applications in filtration systems,porous bearings,porous layer insulation,biomechanics,geomechanics etc.Motivated by such applications,in this article,a numerical study of entropy generation impacts on the heat and momentum transfer in time-dependent laminar incompressible boundary layer flow of a Casson viscoplastic fluid over a uniformly heated vertical cylinder embedded in a porous medium is presented.Darcy’s law is used to simulate bulk drag effects at low Reynolds number for an isotropic,homogenous porous medium.Heat line visualization is also included.The mathematical model is derived and normalized using appropriate transformation variables.The resulting non-linear time-dependent coupled governing equations with associated boundary conditions are solved via an implicit finite difference method which is efficient and unconditionally stable.The outcomes show that entropy generation and Bejan number are both elevated with increasing values of Darcy number,Casson fluid parameter,group parameter and Grashof number.To analyze the heat transfer process in a two-dimensional domain,plotting heat lines provides an excellent approach in addition to streamlines and isotherms.It is remarked that as the Darcy number increases,the deviations of heat lines from the hot wall are reduced.
