Ground elevation estimation is vital for numerous applications in autonomous vehicles and intelligent robotics including three-dimensional object detection,navigable space detection,point cloud matching for localizati...Ground elevation estimation is vital for numerous applications in autonomous vehicles and intelligent robotics including three-dimensional object detection,navigable space detection,point cloud matching for localization,and registration for mapping.However,most works regard the ground as a plane without height information,which causes inaccurate manipulation in these applications.In this work,we propose GeeNet,a novel end-to-end,lightweight method that completes the ground in nearly real time and simultaneously estimates the ground elevation in a grid-based representation.GeeNet leverages the mixing of two-and three-dimensional convolutions to preserve a lightweight architecture to regress ground elevation information for each cell of the grid.For the first time,GeeNet has fulfilled ground elevation estimation from semantic scene completion.We use the SemanticKITTI and SemanticPOSS datasets to validate the proposed GeeNet,demonstrating the qualitative and quantitative performances of GeeNet on ground elevation estimation and semantic scene completion of the point cloud.Moreover,the crossdataset generalization capability of GeeNet is experimentally proven.GeeNet achieves state-of-the-art performance in terms of point cloud completion and ground elevation estimation,with a runtime of 0.88 ms.展开更多
The expressions for nucleation rate in metallic melt on the ground and under elevated gravity have been derived theoretically and the effects of gravity and elevated gravity on nucleation rate have been discussed. A c...The expressions for nucleation rate in metallic melt on the ground and under elevated gravity have been derived theoretically and the effects of gravity and elevated gravity on nucleation rate have been discussed. A comparison of nucleation rate under microgravity with those on the ground and under elevated gravity has also been made展开更多
When water resource or quality problems associated with phreatic water in geological settings are studied, information about water table elevations is often crucial. In those cases where the water table is a subdued r...When water resource or quality problems associated with phreatic water in geological settings are studied, information about water table elevations is often crucial. In those cases where the water table is a subdued replica of the ground surface, universal cokriging can be used to estimate water table elevations at un-sampled locations on the basis of water table and ground surface elevation measurements obtained at well locations. In this paper, universal cokriging, with ground surface elevation considered as a co-variate, was used to estimate water table elevations. Universal cokriging equations were derived, an iterative method for obtaining experimental variograms was established, and a case study of an initial groundwater flow simulation in the Xiuwu County, Henan Province, China, was presented. In the case study, the initial groundwater flow regime was represented both by universal cokriging with the ground surface elevation serving as a covariate and by universal kriging without the inclusion of ground surface elevation as a covariate. A comparison of the results from these two approaches shows that groundwater levels of phreatic water at locations without measurements in regions with unconsolidated porous media can be estimated more accurately by universal cokriging.展开更多
基金the National Natural Science Foundation of China(No.U2033209)。
文摘Ground elevation estimation is vital for numerous applications in autonomous vehicles and intelligent robotics including three-dimensional object detection,navigable space detection,point cloud matching for localization,and registration for mapping.However,most works regard the ground as a plane without height information,which causes inaccurate manipulation in these applications.In this work,we propose GeeNet,a novel end-to-end,lightweight method that completes the ground in nearly real time and simultaneously estimates the ground elevation in a grid-based representation.GeeNet leverages the mixing of two-and three-dimensional convolutions to preserve a lightweight architecture to regress ground elevation information for each cell of the grid.For the first time,GeeNet has fulfilled ground elevation estimation from semantic scene completion.We use the SemanticKITTI and SemanticPOSS datasets to validate the proposed GeeNet,demonstrating the qualitative and quantitative performances of GeeNet on ground elevation estimation and semantic scene completion of the point cloud.Moreover,the crossdataset generalization capability of GeeNet is experimentally proven.GeeNet achieves state-of-the-art performance in terms of point cloud completion and ground elevation estimation,with a runtime of 0.88 ms.
文摘The expressions for nucleation rate in metallic melt on the ground and under elevated gravity have been derived theoretically and the effects of gravity and elevated gravity on nucleation rate have been discussed. A comparison of nucleation rate under microgravity with those on the ground and under elevated gravity has also been made
基金the National Development Plan for Basic Studies (973 Project: G1999043606), the National Natural Science Foundation of China (Grant No: 40272107) and the Key Grant Project of Chinese Ministry of Education (GrantNo: 104012)
文摘When water resource or quality problems associated with phreatic water in geological settings are studied, information about water table elevations is often crucial. In those cases where the water table is a subdued replica of the ground surface, universal cokriging can be used to estimate water table elevations at un-sampled locations on the basis of water table and ground surface elevation measurements obtained at well locations. In this paper, universal cokriging, with ground surface elevation considered as a co-variate, was used to estimate water table elevations. Universal cokriging equations were derived, an iterative method for obtaining experimental variograms was established, and a case study of an initial groundwater flow simulation in the Xiuwu County, Henan Province, China, was presented. In the case study, the initial groundwater flow regime was represented both by universal cokriging with the ground surface elevation serving as a covariate and by universal kriging without the inclusion of ground surface elevation as a covariate. A comparison of the results from these two approaches shows that groundwater levels of phreatic water at locations without measurements in regions with unconsolidated porous media can be estimated more accurately by universal cokriging.
