Housing vacancy can reflect the destocking degree of the real estate market.Based on the data of 57 opened residential quarters(46,622 units)from 2015 to 2018,this paper constructs a calculation formula of the sales v...Housing vacancy can reflect the destocking degree of the real estate market.Based on the data of 57 opened residential quarters(46,622 units)from 2015 to 2018,this paper constructs a calculation formula of the sales vacancy rate and then analyzes the spatial pattern in Guangzhou’s urban district.The results show that there is obvious differentiation in the spatial pattern of housing sales vacancy in Guangzhou’s urban district,showing a higher spatial pattern in the old area and urban district and a lower spatial pattern in the core area.Subdistricts with high vacancy rates are mainly located in the east of the old area,the south and east of the urban district and near Baiyun Mountain in the north.展开更多
Strike and dip are essential to the description of geological features and therefore play important roles in 3D geological modeling.Unevenly and sparsely measured orientations from geological field mapping pose proble...Strike and dip are essential to the description of geological features and therefore play important roles in 3D geological modeling.Unevenly and sparsely measured orientations from geological field mapping pose problems for the geological modeling,especially for covered and deep areas.This study developed a new method for estimating strike and dip based on structural expansion orientation,which can be automatically extracted from both geological and geophysical maps or profiles.Specifically,strike and dip can be estimated by minimizing an objective function composed of the included angle between the strike and dip and the leave-one-out cross-validation strike and dip.We used angle parameterization to reduce dimensionality and proposed a quasi-gradient descent(QGD)method to rapidly obtain a near-optimal solution,improving the time-efficiency and accuracy of objective function optimization with the particle swarm method.A synthetic basin fold model was subsequently used to test the proposed method,and the results showed that the strike and dip estimates were close to the true values.Finally,the proposed method was applied to a real fold structure largely covered by Cainozoic sediments in Australia.The strikes and dips estimated by the proposed method conformed to the actual geological structures more than those of the vector interpolation method did.As expected,the results of 3D geological implicit interface modeling and the strike and dip vector field were much improved by the addition of estimated strikes and dips.展开更多
基金This research was funded by the National Natural Science Foundation of China(No.41871150,No.42101186)GDAS Special Project of Science and Technology Development(No.2020GDASYL-20200104001)National Key Research and Development Program(No.2019YFB2103101),Natural Science Foundation of Guangdong Province(No.2019A1515011653).
文摘Housing vacancy can reflect the destocking degree of the real estate market.Based on the data of 57 opened residential quarters(46,622 units)from 2015 to 2018,this paper constructs a calculation formula of the sales vacancy rate and then analyzes the spatial pattern in Guangzhou’s urban district.The results show that there is obvious differentiation in the spatial pattern of housing sales vacancy in Guangzhou’s urban district,showing a higher spatial pattern in the old area and urban district and a lower spatial pattern in the core area.Subdistricts with high vacancy rates are mainly located in the east of the old area,the south and east of the urban district and near Baiyun Mountain in the north.
基金supported by the National Key Research and Development Program of China(No.2019YFC0605102)the National Natural Science Foundation of China(Grant No.41972307).
文摘Strike and dip are essential to the description of geological features and therefore play important roles in 3D geological modeling.Unevenly and sparsely measured orientations from geological field mapping pose problems for the geological modeling,especially for covered and deep areas.This study developed a new method for estimating strike and dip based on structural expansion orientation,which can be automatically extracted from both geological and geophysical maps or profiles.Specifically,strike and dip can be estimated by minimizing an objective function composed of the included angle between the strike and dip and the leave-one-out cross-validation strike and dip.We used angle parameterization to reduce dimensionality and proposed a quasi-gradient descent(QGD)method to rapidly obtain a near-optimal solution,improving the time-efficiency and accuracy of objective function optimization with the particle swarm method.A synthetic basin fold model was subsequently used to test the proposed method,and the results showed that the strike and dip estimates were close to the true values.Finally,the proposed method was applied to a real fold structure largely covered by Cainozoic sediments in Australia.The strikes and dips estimated by the proposed method conformed to the actual geological structures more than those of the vector interpolation method did.As expected,the results of 3D geological implicit interface modeling and the strike and dip vector field were much improved by the addition of estimated strikes and dips.
