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Xi X.,National University of Defense Technology | Chen Z.,National University of Defense Technology | Sun G.,National University of Defense Technology | Sun G.,Chinese Naval Aeronautical Engineering Academy | Hou J.,National University of Defense Technology
Applied Optics | Year: 2011

We propose two novel methods to make mode-field expanders using photonic crystal fibers (PCFs). By heating and collapsing the center rings of airholes around the core using the selective airhole collapse technique, we enlarge the core of the fibers and get mode-field expanders. Meanwhile, by heating and controlled shrinking all airholes of the PCFs, power confinement in the core will decrease and the mode-field diameter of the fibers will be enlarged, too. Both methods are studied in theory and experiment. © 2011 Optical Society of America. Source

Guang H.,Yantai University | Shengzhi Y.,Chinese Naval Aeronautical Engineering Academy
Journal of Software | Year: 2011

Infrared imaging guidance is a research hotspot in accurate terminal guidance field now. An idea on automatic extraction of region (ROI) of interest in infrared serial images is proposed in order to treat intelligently infrared serial images which are captured. The target detection algorithm of target is researched and the applying scene of the target detection algorithm is confirmed based on analysis for the features of infrared serial images. According to differences of detection algorithm for infrared serial images between static and dynamic scenes, the corresponding detection and extraction algorithm of ROI is discussed respectively. The algorithms are all simulated in real scene. A new stepwise approaching and recurring threshold search algorithm based on two-dimensional maximum entropy principle was proposed by studying recurring formulation optimized of two-dimensional maximum entropy in order to realize to detect target and extract ROI of serial images under complex background. The algorithm above realizes automatic extraction of ROI in Infrared serial images. The results improve the efficiency of accurate terminal guidance and they have good application value by practicing. © 2011 ACADEMY PUBLISHER. Source

Chu X.,Chinese Naval Aeronautical Engineering Academy
Xitong Fangzhen Xuebao / Journal of System Simulation | Year: 2015

Three are two bottlenecks during training: irregular form display simulation of weather target and display simulation of electromagnetic interference in AEW radar training simulator. The weather target display was realized by building weather controlling model and irregular form of weather target based on Bezier Curve and path developed was simulated by VC++. Interference display of AEW radar was realized by building model of various interference patterns and rejecting operation was simulated by building operating model. A lot of difficulties of PPI for AEW radar training simulator were settled: such as random distribution of weather target, irregular form of weather target, adjusting of parameters of weather target display, interference setting and display randomness. Simulation results are effective in practice, which could provide realistic display of weather target, interference for radar operator and good effect in battle ©, 2015, Chinese Association for System Simulation. All right reserved. Source

Shao X.,Chinese Naval Aeronautical Engineering Academy
Jisuanji Fuzhu Sheji Yu Tuxingxue Xuebao/Journal of Computer-Aided Design and Computer Graphics | Year: 2015

This paper we put forward an orientation histogram based algorithm for estimating local orientation angles after summarizing the existing orientation estimation methods and pointing out the problems of quadrature filters. The method computes the vector sum of all neighboring ball voting vectors for an object image pixel to get its orientation angle's histogram and search out the peak value of the histogram as its orientation angle. These orientation angles are used for later tensor voting process as orientation information. Four groups of experiments are performed on typical contours to compare the contour inpainting effect and the precision. Experimental results on edge map of city road and noisy images show that the proposed algorithm works well as basic orientation estimation method for more intact contour, less clutter pixels and robust to noises. ©, 2015, Institute of Computing Technology. All right reserved. Source

Zhang W.,Naval Arming Academy | Zhang W.,Chinese Naval Aeronautical Engineering Academy
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2010

Heavyweight shipboard equipments must be tested on a floating shock platform(FSP), however, the shock test is time-consuming, laborious and expensive. The finite element modeling and simulation can provide a viable and cost effective alternative to shock tests. The objective of the paper is to examine the response of shipboard equipment on a floating shock platform(FSP) using nonlinear ABAQUS finite element software. The results can provide a reference for the evaluation of shipboard equipment's shock resistivity and the design of large FSP. Source

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