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Ming L.,Wuhan University | Ming L.,Key Laboratory of Watershed Ecology and Geographical Environment Monitoring | Ming L.,Jiangxi Provincial Geomatics Center | Fang P.Y.,Key Laboratory of Watershed Ecology and Geographical Environment Monitoring | Fang P.Y.,Jiangxi Provincial Geographical National Conditions Monitoring and Remote Sensing Institute
Cybernetics and Information Technologies | Year: 2015

Considering the prevention and management of the major emergencies in China and the increasingly severe environmental security situations, a visualization emergency solution, based on a mobile mapping system is proposed. This paper studies the key technologies of a mobile mapping system in emergency management. It considers the design of a total factor and full-texture real map, which is measurable and can be marked through the mobile mapping technology. It also proposes the application of a real map in emergency cases, which has large practical significance. Source


Liu D.-E.,Jiangxi University of Science and Technology | Liu D.-E.,Key Laboratory of Watershed Ecology and Geographical Environment Monitoring | Yuan X.-G.,Zhuhai Dahengqin Technology Development Co. | Shen J.-W.,Southwest University | And 2 more authors.
Chinese Journal of Engineering Design | Year: 2015

In view of the traditional rainwater pipe network planning and design, most rainwater catchments were classified by the road network not divided according to the terrain characteristics adaptively, which leading to the results that the hydrological parameters often differed from the actual situations. A method was proposed to automatically extract the hydrological parameters by GIS. First, the DEM was built. It took the road network into account, and integrated with city planning data and the condition of developed city bottom. Then, the hydrological analysis tools and spatial a-nalysis tools of GIS were employed to automatically extract the hydrological parameters based on the simulation terrain. Under the hydrological parameters and road weight, the geometric network tool of GIS was used to build directed network of rainwater drainage system. At last, SWMM was used to simulate the rainfall and analyze which pipe was being flooded, and then the best case of rainwater pipe network was given. The test results show that the rainfall pipe network designing scheme obtained from this method is clearly better than the traditional designing scheme. Source


Wang L.,East China Institute of Technology | Wang L.,Key Laboratory of Watershed Ecology and Geographical Environment Monitoring | Xu G.,East China Institute of Technology | Xu G.,Wuhan University
Wuhan Daxue Xuebao (Xinxi Kexue Ban)/Geomatics and Information Science of Wuhan University | Year: 2016

Considering the situation that the weight matrix of observation vector and coefficient matrix may be inaccurate, an available algorithm is introduced in this paper, which is derived on the basis of combining the Helmert variance component estimation with a kind of fast weighted total least squares algorithm in the errors-in-variables models. And the derivative process of the fast weighted total least squares is described in detail and the comparison with three other algorithms is implemented in this paper. Using the fast weighted total least squares algorithm combining Helmert variance component estimation derived in this paper, the stochastic model and the unknown parameters of the functional model can be solved simultaneously. Three empirical examples, two straight line fitting and one linear parameter estimation, are also used to investigate the application of posteriori estimation of stochastic model on weighted total least squares problem. Results show that the algorithm is very effective. © 2016, Wuhan University. All right reserved. Source


Liu D.,Jiangxi University of Science and Technology | Liu D.,Key Laboratory of Watershed Ecology and Geographical Environment Monitoring | Xiong Z.,Jiangxi University of Science and Technology | Shen J.,Southwest University | And 2 more authors.
Jisuanji Fuzhu Sheji Yu Tuxingxue Xuebao/Journal of Computer-Aided Design and Computer Graphics | Year: 2016

To take full advantage of the multi-core CPU to quickly create the vector terrain based on a large number of disperse points, this paper proposed a multi-core parallel algorithm to create the full topological D-TIN. Firstly, the quad-edge structure was chose to design the D-TIN data structure, and a series of function interfaces were developed to manipulate it; and given consideration to the data load balancing within threads and well-distributed in spatial, the method of coordinate sorting was used to divide the discrete points set into equal parts in logical; then, the serial construction algorithm of D-TIN was developed based on the periodicity of "creation-melting-creation" of the convex hull of the disperse point set and the divide-and-conquer algorithm; lastly, it was taken as the kernel of D-TIN parallel construction algorithm and OpenMP as the model of multi-core parallel programming, then the parallel construction of D-TIN was achieved based on the stand-alone multi-core CPU. The experimental results show that the efficiency of this algorithm is significantly higher than that of the serial algorithm when the data is lager, and the D-TINs created by them are completely consistent; and there is negative correlation between the number of threads used and the total elapsed time. © 2016, Institute of Computing Technology. All right reserved. Source


Wang L.,East China Institute of Technology | Wang L.,Jiangxi Province Key Laboratory for Digital Land | Wang L.,Key Laboratory of Watershed Ecology and Geographical Environment Monitoring | Yu D.,East China Institute of Technology | Lu K.,East China Institute of Technology
Cehui Xuebao/Acta Geodaetica et Cartographica Sinica | Year: 2015

On the basis of complex least squares adjustment method (CLSAM), the theory of complex total least squares adjustment method (CTLSAM) is proposed. The algorithms of complex total least squares and complex LS-TLS method are derived. Through two examples, the complex LS method under the adjustment criterions that minimize the sum of squares of the module of observation vector residual (adjustment criterion 1) and the sum of squares of the real part and imaginary part of the observation vector (adjustment criterion 2), the complex TLS method under the adjustment criterions that minimize the sum of squares of the module of observation vector and coefficient matrix residual (adjustment criterion 3) and the sum of squares of the real part and imaginary part of the observation vector and coefficient matrix residual (adjustment criterion 4) are compared and analyzed respectively. The results of two examples show that the CLSAM under the adjustment criterion 1 is more reasonable than the adjustment criterion 2; the CTLSAM under the adjustment criterion 3 is more accurate than the adjustment criterion 4; the CTLSAM under the adjustment criterion 3 is better than the CLSAM under the adjustment criterion 1 when the coefficient matrix contains stochastic noise. ©, 2015, SinoMaps Press. All right reserved. Source

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