Sichuan Normal University is the oldest normal university located in Chengdu, Sichuan, China. It is the largest provincial key university with the most complete courses offered among the provincial universities and colleges in Sichuan province. It has about 35,000 students with 32,000 full-time undergraduates and 3,000 graduate students. There are about 3,000 faculty and staff, of whom 770 are professors and associate professors, and 150 have Doctorates. 17 academicians of the Chinese Academy of science and the Chinese Academy of Engineering have accepted SNU positions as chief, part-time or emeritus professors. Wikipedia.
Ji X.,Sichuan Normal University
Applied Physics B: Lasers and Optics | Year: 2010
The effective radius of curvature of hyperbolic and sinusoidal Gaussian beams in free space and turbulent atmosphere is studied analytically and numerically. It is shown that the radius of curvature rises with growing source size, and changes slowly with wavelength. In general, given the same source and propagation settings, the beams can be listed in descending order of radius of curvature magnitudes as sinh Gaussian, cosh Gaussian, sine Gaussian, pure Gaussian and cos Gaussian beams. However, the radius of curvature and the difference of the radius of curvature between the different beams reduce with growing strength of turbulence because the beam's spatial phase distribution is destroyed by turbulence. © Springer-Verlag 2010.
Ji X.-L.,Sichuan Normal University
Wuli Xuebao/Acta Physica Sinica | Year: 2010
The analytical expressions for the mean-squared beam width and the far-field divergence angle of radial Gaussian array beams in atmospheric turbulence are derived. The influence of turbulence on the spreading and directionality is studied in detail. It is shown that for the coherent combination, the radial Gaussian array beams with smaller beam number N and larger radial radius r0 are less affected by the turbulence. The spreading of radial Gaussian array beams for the coherent combination is smaller than that for the incoherent case. However, the spreading of radial Gaussian array beams for the coherent combination is more affected by turbulence than that for the incoherent case. Specially, the mean-squared beam width in the far-field for the coherent combination is the same as that for the incoherent case when N is small enough or r0 is large enough. On the other hand, the condition under which radial Gaussian array beams for both coherent and incoherent combinations have the same far-field divergence angle as a single Gaussian beam is also given. The main results are interpreted physically. © Chin.Phys.Soc.
Liao Z.,Sichuan Normal University
Advances in Mathematical Physics | Year: 2013
Existing fractional-order Perona-Malik Diffusion (FOPMD) algorithms used in noise suppressing suffer from undesired artifacts and speckle effect, which hamper FOPMD used in low-dosed X-ray computed tomography (LDCT) imaging. In this paper, we propose a new FOPMD method for low-dose computed tomography (LDCT) imaging, which is called regularized fully spatial FOPMD (RFS-FOPMD), whose numerical scheme is also given based on Grünwald-Letnikov derivative (G-L derivative). Here, fully spatial FOPMD represents all the integer-order derivatives (IODs) in the right hand of Perona-Malik Diffusion (PMD) which are replaced by fractional-order derivatives (FODs). Since the new scheme has advantages of both regularization and FOPMD, it has good abilities in singularities preserving while suppressing noise. Some real sinogram of LDCT are used to compare the different performances not only for some classical but also for some state-of-art diffusion schemes. These schemes include PMD, regularized PMD (RPMD), and FOPMD in (Hu et al. 2012). Experimental results show that besides good ability in edge preserving, the new scheme also has good stability for iteration number and can avoid artifacts and speckle effect with suitable parameters. © 2013 Zhiwu Liao.
Chang S.,Sichuan Normal University
International Journal of Advancements in Computing Technology | Year: 2012
This article through the use of data sets KDDCup99 data set on the intrusion detection, and simulation data pretreatment, attribute reduction, invasion, finally, generating rules test data set, through the test test rate and by mistake examining rate of the experimental results are analyzed and compared, in the whole process of intrusion detection, attribute reduction algorithm generated invasion rules to play a key role, it also determines the intrusion detection performance, so, choose a good effect is particularly important attribute reduction algorithm is proposed. Based on this, the paper analyzes the current attribute reduction algorithm, and proposes an improved attribute reduction algorithm is proposed.
Ding X.P.,Sichuan Normal University
Journal of Global Optimization | Year: 2012
A new class of bilevel generalized mixed equilibrium problems involving set-valued mappings is introduced and studied in Banach spaces. First, an auxiliary generalized mixed equilibrium problem (AGMEP) to compute the approximate solutions of the generalized mixed equilibrium problems (GMEP) and bilevel generalized mixed equilibrium problems (BGMEP) involving set-valued mappings is introduced. By using a minimax inequality, the existence and uniqueness of solutions of the AGMEP is proved under quite mild conditions. By using auxiliary principle technique, new iterative algorithm to compute the approximate solutions of the GMEP and the BGMEP are suggested and analyzed. The strong convergence of the iterative sequences generated by the algorithms are proved under quite mild assumptions. These results are new and generalize some recent results in this field. © Springer Science+Business Media, LLC 2012.