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Scenario of Passive grid connecting two VSC-HVDC transmission systems has been investigated in this paper. A control method with hierarchy is proposed. VSCs have been grouped into a hierarchy of various categories. Distance which denotes the number of connections with strong grid of VSC stations is used to define the hierarchy used in this paper. Different control methods are used in different categories to regulate different variables. This method can be used in DC grids with many VSCs grouped into a hierarchy of various categories. This paper presents a multilayer DC system with a passive AC grid inside the DC grid. The control principle of VSCs connected with the passive grid is investigated. The AC voltage control and active power control is assigned to different VSC based on its power flow in the inside passive AC grid. Also a DC voltage control is integrated in the hierarchy control system to improve the dynamic instability.

The traditional classification and extraction of information about remote sensing is based on spectral information of remote sensing images with man-made interpretation method. Because of the existence of the same objects with different spectrums and different things with same spectrums and the subjectivity of the man-made interpretation, the classification accuracy of this method is low and inefficient. However, the classification technology based on objects adopts the method of multi-scale segmentation to produce the image objects, using the spectral characteristics of remote sensing images. Then, based on the geometric features and topological relations of images objects, the rules of classification are established which are used to extract the information of the images. Studies have shown that this method has better results. In this paper, extraction of water baby information in XiaoTangShan area, as an example, confirms the truth of this method.

Geometric distortion is important in the research of image geometric processing. This paper introduces a unique technique for image processing based on low-altitude UAV (Unmanned Aerial Vehicle) and accordingly generating the DEM and Digital Orthophoto. Through the UAV image Orthorectification and the regional network of radio beam method for adjustment of the whole deal, and then analyzes the impact of accuracy of geometric correction factors. Experiments proved the scheme is reliable which arrange ground control points more dense around the peripheral field.

The normalized constant modulus blind equalization algorithm with adaptive adjustment of the dispersion constant is proposed. The drawback of no convergence of the weight vector due to the improper choice of the dispersion constant in the normalized constant modulus algorithms (NCMA) is overcome.