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155 results on '"Kong, Weihua"'

47. Quickly Planning TF/TA2 Trajectory by Artificial Immune Algorithm

Author

LIU Lifeng, YANG Fei, ZHANG Shuqing, KONG Weihua, and WANG Yinxing

Subjects
artificial immune algorithm, GA, TF/TA2, ComputerApplications_COMPUTERSINOTHERSYSTEMS, lcsh:Mathematical geography. Cartography, lcsh:GA1-1776, path planning
Abstract

Flight path planning by artificial immune algorithm approach met the requirements of aircraft's flyability and operation is proposed for the problem of single and double TF/TA2 flight path planning. Punishment function (affinity function) with comprehensive 3D threat information is designed. A comprehensive threat model is formed including dynamic and static threats and no-fly-zone. Accordingly, single and dual flight paths are planned by AIA, which have been compared with the paths by GA. The results show that, GA's planned a quick and longer path compared under simple threat environment; in complex environments, GA has high failure rate (greater than 95%) for single aircraft, but it is failed for double aircrafts. For the single and double aircrafts, AIA can provides one optimal and more candidate optimal flight paths.

Published
2015

48. RaPC:A Rasterization-based Polygon Clipping Algorithm and Its Error Analysis

Author

FAN Junfu, KONG Weihua, MA Ting, ZHOU Chenghu, JI Min, and ZHOU Yuke

Subjects
rasterization, area error, point in polygon, polygon clipping, lcsh:Mathematical geography. Cartography, winding and tracing, lcsh:GA1-1776, ComputingMethodologies_COMPUTERGRAPHICS
Abstract

Computational efficiencies of traditional vector computing-based polygon clipping algorithms will decrease rapidly when handling polygons contain large amount of vertices. The computing flows of traditional polygon clipping algorithms are tightly coupled with special data structures, which difficult to be optimized in the underlying of them. Under the premise of meeting a certain degree of area errors, the polygon clipping problem can be solved by introducing the idea of rasterization processing. In this research, we proposed a new rasterization processing-based polygon clipping algorithm: the RaPC algorithm, on the basis of analyzing the characteristics of existing algorithms. The area errors of results of the new algorithm are also analyzed and discussed. Experimental results show that the efficiencies of the RaPC algorithm can be enhanced significantly when using large grid cells, and it shows a linear trend growth with the increase of amount of polygon vertices. Compared with the Vatti algorithm, the RaPC algorithm represents more efficiencies on dealing clipping issues between polygons with large amount of vertices, the former shows lower time costs when handling polygons with less vertices. The area error of computing results of the RaPC algorithm is closely related with the grid size, and errors can be reduced using smaller grid sizes. Therefore the RaPC algorithm showed higher efficiencies on processing polygons with large amount of vertices than the Vatti algorithm and presented practical values to some degree.

Published
2015

49. Electrochemical Mg2+ Displacement Driven Reversible Copper Extrusion/Intrusion Reactions for High‐Rate Rechargeable Magnesium Batteries.

Author

Xue, Xiaolan, Chen, Renpeng, Song, Xinmei, Tao, Anyang, Yan, Wen, Kong, Weihua, and Jin, Zhong

Subjects
MAGNESIUM ions, STORAGE batteries, COPPER, COPPER ions, ACTIVATION energy, ELECTRON transport, MAGNESIUM
Abstract

Rechargeable magnesium batteries (RMBs) based on metal Mg anodes have shown great potential owing to the abundant natural resources, high volumetric capacity, and low safety hazard. Nevertheless, the development of RMBs is hampered by the sluggish kinetics of Mg2+ diffusion and the limited cyclability of cathode materials. Herein, nonstoichiometric copper selenide (Cu2–xSe) are synthesized via a solution‐based method and exploited as a durable cathode material based on ionic displacement mechanism for RMBs. The copper ions in the Se2− based sub‐lattices are reversibly exchanged by Mg2+ ions without causing lattice collapse. Owing to the same face‐centered cubic Se2− sub‐lattices and similar unit cell size of Cu2–xSe and MgSe, the energy barrier for lattice reconstruction during cycling processes is very low, significantly improving the rate performance, structural stability, and cycle life of the Cu2–xSe cathode. Moreover, metal Cu is in situ generated during discharging, thus greatly facilitating electron transport. Comprehensive characterizations confirm that the Cu2–xSe cathode undergoes reversible copper ion extrusion/reinjection during the discharge−charge steps. This work suggests the great potential for exploring high‐performance electrode materials based on ionic displacement mechanism for advanced multivalent‐ion secondary batteries. [ABSTRACT FROM AUTHOR]

Published
2021
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