The problem of crustal movement in the Qing-hai-Tibetan Plateau is a hotstopic of the present-day international geodetic world. GPS observations in 1993, 1995 and 1997 are used to survey the three-dimensional displace...The problem of crustal movement in the Qing-hai-Tibetan Plateau is a hotstopic of the present-day international geodetic world. GPS observations in 1993, 1995 and 1997 are used to survey the three-dimensional displacement of GPS monitoring station in the Qinghai-Tibetan Plateau, and to calculate and analyze the present-day crustal movement and strain in the Qinghai-Tibetan Plateau. The result of repeated campaign shows that the crustal movement in the Qinghai-Tibetan Plateau is still compressing in the north and south directions, extending in the west and east directions, and uplifting in the vertical direction. The relative convergence velocity of the Himalayan block is approximately (19.5±1.7)mm/a, the strain velocity is about (5.5±6.0) mm/a, and the uplifting velocity is some (7.6±5.2) mm/a. The compression velocity of the Tibet block relative to Golmud in the north and south directions is (9.3±4.6) mm/a, the strain velocity of the middle part in the west and east directions is (15.6±6.3) mm/a,展开更多
Side scan sonar imaging is one of the advanced methods for seabed study.In order to be utilized in other projects,such as ocean engineering,the image needs to be classified according to the distributions of different ...Side scan sonar imaging is one of the advanced methods for seabed study.In order to be utilized in other projects,such as ocean engineering,the image needs to be classified according to the distributions of different classes of seabed materials.In this paper,seabed image is classified according to BP neural network,and.Genetic Algorithm is adopted in train network in this paper.The feature vectors are average intensity,six statistics of texture and two dimensions of fractal.It considers not only the spatial correlation between different pixels,but also the terrain coarseness.The texture is denoted by the statistics of the co-occurrence matrix.Double Blanket algorithm is used to calculate dimension.Because a uniform fractal may not be sufficient to describe a seafloor,two dimensions are calculated respectively by the upper blanket and the lower blanket.However,in sonar image,fractal has directivity,i.e.there are different dimensions in different direction.Dimensions are different in acrosstrack and alongtrack,so the average of four directions is used to solve this problem.Finally,the real data verify the algorithm.In this paper,one hidden layer including six nodes is adopted.The BP network is rapidly and accurately convergent through GA.Correct classification rate is 92.5%in the result.展开更多
Multi-beam Sonar and Side-scan Sonar compensate each other. In order to fully utilize all information, it is necessary to fuse two kinds of image and data. And the image co-registration is an important and complicated...Multi-beam Sonar and Side-scan Sonar compensate each other. In order to fully utilize all information, it is necessary to fuse two kinds of image and data. And the image co-registration is an important and complicated job before fusion. This paper suggests combining bathymetric data with intensity image, obtaining the characteristic points through the minimal angles of lines, and then deciding the corresponding image points by the maximal correlate coefficient in searching space. Finally, the second order polynomial is applied to the deformation model. After the images have been co-registered, Wavelet is used to fuse the images. It is shown that this algorithm can be used in the flat seafloor or the isotropic seabed. Verification is made in the paper with the observed data.展开更多
In this paper,a dynamic flow-regulation algorithm-oriented network overload control is proposed.It can proportion-ally distribute the load between the high-degree nodes and the low-degree nodes.According to the theore...In this paper,a dynamic flow-regulation algorithm-oriented network overload control is proposed.It can proportion-ally distribute the load between the high-degree nodes and the low-degree nodes.According to the theoretical analysis,the net-work transmission performance of the proposed algorithm is in inverse proportion to the usage rate of the high-degree nodes.Simulations show that the new algorithm is more flexible and can enhance the network capability in most circumstances compared with the shortest path routing algorithm.Moreover,the compari-son with the efficient routing algorism also reveals the prominent performance of the new algorithm.展开更多
基金the National NaturalScience Foundation of China (Grant Nos. 49234070, 49974001 and 49904001) and the National Outstanding Youth Science Foundation (Grant No. 49725411).
文摘The problem of crustal movement in the Qing-hai-Tibetan Plateau is a hotstopic of the present-day international geodetic world. GPS observations in 1993, 1995 and 1997 are used to survey the three-dimensional displacement of GPS monitoring station in the Qinghai-Tibetan Plateau, and to calculate and analyze the present-day crustal movement and strain in the Qinghai-Tibetan Plateau. The result of repeated campaign shows that the crustal movement in the Qinghai-Tibetan Plateau is still compressing in the north and south directions, extending in the west and east directions, and uplifting in the vertical direction. The relative convergence velocity of the Himalayan block is approximately (19.5±1.7)mm/a, the strain velocity is about (5.5±6.0) mm/a, and the uplifting velocity is some (7.6±5.2) mm/a. The compression velocity of the Tibet block relative to Golmud in the north and south directions is (9.3±4.6) mm/a, the strain velocity of the middle part in the west and east directions is (15.6±6.3) mm/a,
文摘Side scan sonar imaging is one of the advanced methods for seabed study.In order to be utilized in other projects,such as ocean engineering,the image needs to be classified according to the distributions of different classes of seabed materials.In this paper,seabed image is classified according to BP neural network,and.Genetic Algorithm is adopted in train network in this paper.The feature vectors are average intensity,six statistics of texture and two dimensions of fractal.It considers not only the spatial correlation between different pixels,but also the terrain coarseness.The texture is denoted by the statistics of the co-occurrence matrix.Double Blanket algorithm is used to calculate dimension.Because a uniform fractal may not be sufficient to describe a seafloor,two dimensions are calculated respectively by the upper blanket and the lower blanket.However,in sonar image,fractal has directivity,i.e.there are different dimensions in different direction.Dimensions are different in acrosstrack and alongtrack,so the average of four directions is used to solve this problem.Finally,the real data verify the algorithm.In this paper,one hidden layer including six nodes is adopted.The BP network is rapidly and accurately convergent through GA.Correct classification rate is 92.5%in the result.
文摘Multi-beam Sonar and Side-scan Sonar compensate each other. In order to fully utilize all information, it is necessary to fuse two kinds of image and data. And the image co-registration is an important and complicated job before fusion. This paper suggests combining bathymetric data with intensity image, obtaining the characteristic points through the minimal angles of lines, and then deciding the corresponding image points by the maximal correlate coefficient in searching space. Finally, the second order polynomial is applied to the deformation model. After the images have been co-registered, Wavelet is used to fuse the images. It is shown that this algorithm can be used in the flat seafloor or the isotropic seabed. Verification is made in the paper with the observed data.
基金Supported by the National Natural Science Foundation of China (60970114 , 41104010)the National Natural Science Foundation of Hubei Province (ZRZ0041)+2 种基金the Science and Technology Project of Wuhan City (201110921292)the Open Fund of the Ministry of Public Security of the Information Network Security Key Laboratory (C10607)the Independent Scientific Research Projects of the Wuhan University Graduate Student (201121102020002)
文摘In this paper,a dynamic flow-regulation algorithm-oriented network overload control is proposed.It can proportion-ally distribute the load between the high-degree nodes and the low-degree nodes.According to the theoretical analysis,the net-work transmission performance of the proposed algorithm is in inverse proportion to the usage rate of the high-degree nodes.Simulations show that the new algorithm is more flexible and can enhance the network capability in most circumstances compared with the shortest path routing algorithm.Moreover,the compari-son with the efficient routing algorism also reveals the prominent performance of the new algorithm.
