Beihang University

Petrochina Company Limited

China Institute of Water Resources and Hydropower Research

Beijing Jishi Huitong Technology Co., Ltd.

Xuejun Zhang

Yin Zhang

Xiaoliang Yuan

Pingyi Wu

Yuandong Hou

Xueyuan Li

Yuanhao Tan

Yan Li

Li Ni Zhang

Shengjie Wang

Lihua Zhao

An Ma

Hongjie Liu

Yizhu Lu

Juan Lv

Wenlong Song

Yuanyuan Duan

Rui Tang

Qinfeng Zhao

Shuqin Wang

Kunhong Liu

Honglei Sun

Jiarui Piao

Jingxuan Lu

Getu Zhaoer

Jie Ouyang

Yuanjun Zhu

Zhicheng Su

Guanjing Wu

The present invention discloses a multi-beamforming optimization method for space-based ADS-B based on a coverage matrix. The method includes: calculating signal-to-noise ratios of received signals based on an ADS-B signal model and an air-space channel model; deriving the correct reception probability of ADS-B signals by a satellite with different signal-to-noise ratios and with different numbers of aircraft on the basis of analyzing a correct decoding probability and a collision probability; and in the case that the constraint of satellite coverage metric is satisfied, aiming at minimizing the update interval of position messages at the update probability of 95%, establishing a digital multi-beamforming optimization model for space-based ADS-B.

Multi-beamforming optimization method for space-based ADS-B based on coverage matrix

The present invention discloses a coevolution-based multi-beamforming optimizing method for space-based ADS-B, which belongs to the field of aviation technologies. According to this method, after initializing population and acquiring an initial optimal solution, optimization parameters are firstly grouped randomly so that all beams form several significant uncovered regions. Then, grouping is performed by an adaptive grouping strategy based on the relative orientation between the mean center of the largest uncovered region and the direction of each beam, so that the parameters quickly converge to a full-coverage state within the half angle of the satellite. Finally, grouping is performed by a grouping strategy based on the aircraft density covered by each beam to obtain optimally the minimal update time interval under a full-coverage constraint. The method of the present invention adopts an adaptive dynamic grouping strategy based on the beam pointing, the orientation of uncovered region and the aircraft density covered by each beam, such that the algorithm performance and optimization efficiency can both be improved.

Coevolution-based multi-beamforming optimizing method for space-based ADS-B

The present invention discloses a method for UAV path planning in urban airspace based on a safe reinforcement learning (RL) algorithm called shield-DDPG, which combines a shield model with a DDPG algorithm and pertains to the field of UAV technologies. The method takes an attractive force from the destination point into account when an action is selected, which improves the convergence speed of the algorithm and also improve the efficiency of UAV path planning. More importantly, the method provided by the present invention can effectively verify safety of an action in terms of the air collision risk and the ground impact risk, and ensure that a final output of the algorithm is a safe optimal solution. Therefore, the present invention can effectively solve the problem that when the RL algorithm is used for UAV path planning, it is difficult to ensure the safety of the learning or execution process due to the lack of hard constraints.

Method for UAV path planning in urban airspace based on safe reinforcement learning

A Region Merging image segmentation algorithm based on boundary extraction is disclosed, comprising the steps of calculating a gradient image, extracting a boundary and carrying out initial segmentation and Region Merging, wherein each pixel is regarded as one region when initial segmentation is not conducted. In the Region Merging process, the portion of the common boundary of two adjacent regions that lies on the boundary image is taken as the merging cost, the regions are merged according to the ascending order of the mean gradient value inside the region, and a texture difference evaluation mechanism is introduced to reduce the wrong segmentation. The algorithm solves the problems of the other current segmentation algorithms, such as over-segmentation, easy to be influenced by noise and illumination, large in computation and memory consumption, in need of a large number of samples being marked manually and the like. Besides, all regions or all categories achieve the best segmentation result on one final segmentation result. These advantageous features can reduce the computational resource consumption of subsequent tasks and improve their results.

Region merging image segmentation algorithm based on boundary extraction

The present disclosure relates to a multimedia network data processing system, comprising: a head-end switch, which transmits multimedia network data of the data that is sent from a server to a terminal device to a head-end network processor, wherein the multimedia network data is multimedia network data based on the TCP/HTTP protocol; a head-end network processor, which encapsulates the multimedia network data to form a UDP packet and sends the UDP packet to a unidirectional broadcasting optical fiber network; and a data processing module, which receives the UDP packet from the unidirectional broadcasting optical fiber network and decapsulates the UDP packet to obtain the multimedia network data based on the TCP/HTTP protocol for the terminal device to play. A video-on-demand service based on the TCP/HTTP protocol can be realized on the basis of the existing network systems in which the unidirectional channel and the bidirectional channel are separated. And the programs transmitted by radios and TVs can be enriched while the requirements for bandwidth of uplink transmission and bandwidth of downlink transmission can be satisfied.

Multimedia network data processing system

The present invention relates to a method for the selective hydrogenation of an unsaturated compound, particularly a method in an unsaturated compound or a mixture containing unsaturated compounds for increase of the light sulphides weight, hydrogenation of a polyunsaturated compound and isomerization of a monounsaturated compound. The method uses a supported catalyst. The supported catalyst contains at least one Group VIB non-noble metal oxide and at least one Group VIII non-noble metal oxide deposited on a carrier; and the catalyst has an optimized acid distribution on the surface of the catalyst, and more preferably has an optimized Group VIII/VIB metal ratio and a Group VIII non-noble metal density per unit of catalyst surface area.

Method for selective hydrogenation of unsaturated compound

The present invention relates to a selective hydrogenation catalyst for an unsaturated compound. The supported catalyst contains at least one Group VIB non-noble metal oxide and at least one Group VIII non-noble metal oxide deposited on a carrier; and the catalyst has an optimized acid distribution on the surface of the catalyst, and more preferably has an optimized Group VIII/VIB metal ratio and a Group VIII non-noble metal density per unit of catalyst surface area. Using the catalyst of the present invention can have the following advantages: the weight increase of light sulphides in an unsaturated compound or a mixture containing unsaturated compounds, the hydrogenation of a polyunsaturated compound, the isomerization of a monounsaturated compound, high operation flexibility and a significant improvement in the effects of a hydrogenation treatment.

Selective hydrogenation catalyst for unsaturated compound

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Beijing, China

Xuejun Zhang