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Wang M.,Xian Yang Normal College | Li Y.L.,Xian Yang Normal College | Wang Y.,Beijing Institute of Environmental Characteristics | Xiang N.,Xian Yang Normal College | Xiang N.,Xidian University
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2013

It has used the two-frequency mutual coherent function to study pulse scattering from one dimensional perfectly conducting rough surface. So this paper is mainly focused on that the analytical expressions for incoherent mutual function (MCF) for pulse scattering from one-dimensional random rough surface are obtained based on the Kirchhoff's approximation. According to the analytical solutions, numerical methods are shown that coherent and incoherent mutual function (MCF) change with the coherence bandwidth frequency difference and scattering angles in different incident angles incidence on laser (1.06μm) according to the mean of fluctuating heights and correlation length of the rough surfaces. And some important scattering characteristics of the coherent and incoherent mutual function (MCF) are be obtained in details. Our works is helpful when investigating the statistical characteristics of laser scattering fields of objects with rough surface. © 2013 SPIE. Source

Yuan X.-J.,Beijing Institute of Environmental Characteristics
Chinese Physics Letters | Year: 2012

In comparison with the phenomenon of negative index refraction observed in artificial meta-materials, it is interesting to ask if this type of behavior also exists or not in reaction-diffusion systems that support nonlinear chemical waves. Previous studies indicate that the negative index refraction could occur on a interface between a medium of a normal wave and a medium that supports anti-waves. Here we investigate the phenomenon in the complex Ginzburg - Landau equation (CGLE) in a close relationship with the quantitative model for the chloriteiodide-malonic acid (CIMA) reaction. The amplitude equation CGLE is deduced from the CIMA reaction, and simulations with mapped parameters from the reaction-diffusion equation reveal that the competition between normal waves and anti-waves on the interface determines whether the negative index refraction occurs or not. © 2012 Chinese Physical Society and IOP Publishing Ltd. Source

Hu L.P.,Beijing Institute of Environmental Characteristics
Proceedings of 2011 IEEE CIE International Conference on Radar, RADAR 2011 | Year: 2011

An image feature extraction technique, two-directional two-dimensional k-nearest neighbour discriminant analysis ((2D) 2k-NNDA), is presented from the viewpoint of the k-nearest neighbour (k-NN) classification, which is an extension of 2DNNDA based the idea of the nearest neighbour (1-NN) classification. Similar to 2DNNDA, (2D) 2k-NNDA makes use of the matrix representation of images and does not assume the class densities belong to any particular parametric family. (2D) 2k-NNDA is applied to target recognition and the results demonstrate that (2D) 2k-NNDA achieves at least the same or even higher recognition accuracy than the existing 2D subspace methods. © 2011 IEEE. Source

Liu J.,Science and Technology on Optical Radiation Laboratory | Deng R.,Science and Technology on Optical Radiation Laboratory | Wei A.,Beijing Institute of Environmental Characteristics | Yu Z.,Beijing Institute of Environmental Characteristics
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering | Year: 2014

For the miniaturization and portability demands of solar simulator, a portable solar simulator was designed. Illumination in 1.2 m×1.2 m rectangular irradiated area not less than 0.02 solar constant was required; furthermore, the un-uniformity of irradiated surface less than 5% was also needed. The system mainly consisted of short-arc xenon lamp, ellipsoidal reflector, fiber optic beams, and a group of collimating lens. Through software simulation and experimental verification, the results met all the requirements. Experimental results show that the method that designing a portable solar simulator with short-arc xenon lamp, ellipsoidal reflector, fiber optic beams, integral stick, and projection collimator lens group is effective and feasible. ©, 2014, Chinese Society of Astronautics. All right reserved. Source

Hu L.,Beijing Institute of Environmental Characteristics | Liu H.,Xidian University | Zhou P.,Beijing Institute of Environmental Characteristics
Lecture Notes in Electrical Engineering | Year: 2010

An image feature extraction method, generalized 2-dimensional clustering-based discriminant analysis (G2DCDA), is proposed. This method can compress images along both rows and columns, and thus overcoming the drawbacks of too large feature matrices of 2DCDA. In addition, similar to 2DCDA, G2DCDA not only has the computational advantages of the 2D subspace methods available, but can deal with the multimodal distribution problems. Experiments conducted on the moving and stationary target acquisition and recognition (MSTAR) public database demonstrate that G2DCDA is more efficient than some 2D existing subspace methods, such as 2D principal component analysis (2DPCA), 2D linear discriminant analysis (2DLDA) and 2DCDA. Moreover, G2DCDA achieves higher recognition rates and lesser memory requirements. © 2010 Springer-Verlag Berlin Heidelberg. Source

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