Guilin, China
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Xie C.-M.,Beihang University | Xie C.-M.,Guilin Air Force Academy | Zhao Y.,Beihang University | Yang C.-C.,Air Defense Force Command Academy
Xi Tong Gong Cheng Yu Dian Zi Ji Shu/Systems Engineering and Electronics | Year: 2011

Aiming at the remarkable influence of wing flexure noise on transfer alignment (TA) filtering, an online compensation algorithm is proposed on the assumption that the wing flexure noise is a time varying multi-order colored measurement noise from its character analysis. On the basis of typical Kalman filtering equations, new filtering equations capable of compensating multi-order colored noise without dimension extension are derived. According to the series measuring data and aided by a model estimating error F testing method, the algorithm is used to iteratively estimate auto-regressive orders, auto-regressive coefficients and white noise of wing flexure noise online which are thus taken advantage of to construct the measurement data, measurement matrix and measurement noise to perform compensating filtering. Finally, the algorithm is applied to a velocity plus attitude TA matching plan and compared with the method substituting wing flexure noise by pouring white measurement noise and extending system states. Simulation results show that the algorithm is of strong adaptability to new measurement data under time varying wing flexure noise as well as steady convergence and high accuracy estimating performance, which is feasible to achieve rapid and high accuracy airborne missile TA under hard air environment.

Ni Y.,Tsinghua University | Ni Y.,Guilin Air Force Academy | Fan Y.,Tsinghua University
Advances in Engineering Software | Year: 2010

Web services composition is becoming more and more important in today's service oriented business environment. We need to compose services from different providers together to fulfill the business goals that cannot be satisfied by any single service. However, different services often have semantic inconsistencies which may lead to the failure of the services composition. In order to verify the correctness of the Semantic Web Services composition, this paper proposed a composition model of Coloured Petri Nets which is transformed from OWL-S model. This model can express the logical relations among the sub-processes of the services composition explicitly, and verify the correctness of the services composition using formalized methods of Coloured Petri Nets. This paper presented the verification algorithms for the reachability, boundness and semantic consistency of composed services. Furthermore, an example of collaborating design process was given to simulate and execute the model. © 2010 Elsevier Ltd. All rights reserved.

Ni Y.,Tsinghua University | Ni Y.,Guilin Air Force Academy | Fan Y.-S.,Tsinghua University
Jisuanji Jicheng Zhizao Xitong/Computer Integrated Manufacturing Systems, CIMS | Year: 2011

To resolve the semantic inconsistency of multi-domain business process collaboration in Service Oriented Architecture, a multi-domain business process collaboration architecture based on model transformation was proposed. Collaborative ontology transforming into the Web Services composition model was realized by meta modeling framework of meta-object facility. This method remained the original semantic information in processes and Web Services, provided a flexible method for model transformation so as to ensure the semantic consistency of collaborative business processes. The framework and transformation method were implemented in project ImportNET which was funded by European Commission, and the effectiveness was illustrated.

Liao S.,Guilin Air Force Academy | Gong M.,Tsinghua University
Optics Communications | Year: 2011

Predicting mode-dependent bending loss is important for large-mode-area (LMA) fibers to strip out unwanted modes. In order to seek a reasonable calculation method, a new bending loss formula that allows for both mode field distortion and weaker mode confinement was derived in detail. Based on the formula, a semi-analytical method was introduced to calculate the mode bending loss for LMA fibers. By combining the applications of the finite element method, discrete Fourier transforms and numerical integral, the method is valid for LMA fibers with arbitrary refractive index profile. The obtained loss characteristics are basically consistent with the previous results. This accordance demonstrates the feasibility and generality of the semi-analytical method. © 2011 Elsevier B.V. All rights reserved.

Liao S.,Guilin Air Force Academy | Gong M.,Tsinghua University
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering | Year: 2011

In order to overcome the limitations of the nonlinear effects and optical damage, the high power active fibers usually have large mode areas. The current main technical means used in large mode area fibers were reviewed, which include the fiber structural design, mode control and selection, and mode transform. Then the basic idea of the various technical means and the primary characteristics of the relevant large mode area fibers were described. On the basis, it was pointed that the difficult problems like mode distortion as well as the high order mode suppression, the integration analysis for laser systems and the fiber fabrications when they were applied in the actual applications. Finally, by comparing the fiber performance characteristic, processing ease, and the study level of the theoretical and experimental aspects, the mode transform with the higher order mode fiber and the gain guiding, index anti-guiding approach are considered to be the two most effective ways to achieve the large mode area fiber lasers. It is possible to improve the mode areas.

Le X.,University of Electronic Science and Technology of China | Cheng J.,University of Electronic Science and Technology of China | Li M.,University of Electronic Science and Technology of China | Li M.,Guilin Air Force Academy
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering | Year: 2011

Motion blur is one of the most common blurs that degrades images. The restoration of motion- blurred images is highly dependent on accurate estimation of the point spread function. For uniform linear motion blurred images, the motion direction and blur extent are two key parameters determining the point spread function. The mathematic principle of Radon transform and procedures of using it to identify the motion direction were introduced. Aiming at the dominant cross-shaped bright lines showing up in the Fourier spectra of the real blurred images taken by digital camera, the cause of formation was analyzed and an improved algorithm was proposed. According to the properties of the bright lines, sub-blocks method was adopted to avoid detection interference. Experimental results show the validity and effectiveness of the presented method.

Xia J.,Hunan University of Science and Technology | Xiong J.-L.,Hunan University of Science and Technology | Xu X.,Hunan University of Science and Technology | Qin H.,Guilin Air Force Academy
2010 International Conference on Intelligent Computation Technology and Automation, ICICTA 2010 | Year: 2010

Hessian matrix is an important tool to analysis local characters of images, and detectors based on it are used widely in camera calibration.This paper derives a new representation of Hessian matrix by wavelet transform modulus and furtherer proposed a multiscale sub-pixel corner detector based on Hessian matrix and wavelet. It is expected to detect the corners at different scales and overcome the drawback of the singlescale detectors, which may usually either miss significant corners or detect false corners due to noise. For other kinds of corners besides X-corners mentioned in this paper, relative multiscale detectors based on Hessian matrix can be easily designed in the same way as this article. Computer simulation experiments show that at low noise level our algorithm is slightly more accurate than traditional single scale algorithm, and that at high noise level our algorithm is still robust enough to detect most corners when the traditional detector fails. © 2010 IEEE.

Lin Y.,Guilin Air Force Academy
Binggong Xuebao/Acta Armamentarii | Year: 2010

A method of determining optimum aperture distributions of Cassegrain reflector antennas was presented. The necessity of seeking optimum aperture distribution of Cassegrain reflector antennas was illustrated by comparison of the sidelobe levels between Cassegrain reflector antennas and parabolic reflector antennas of the same aperture distributions as that of the former; optimum aperture distributions of Cassegrain reflector antennas is determined by means of simultaneous equations of constraint conditions of sidelobe level and aperture efficiency; other possible applications of the method of determining optimum aperture distributions of Cassegrain reflector antennas were enumerated. The investigated result demonstrates that compared with common aperture distribution, the optimum aperture distribution has better sidelobe level and aperture efficiency, i.e. the optimum aperture distribution has higher aperture efficiency at the same sidelobe level or lower sidelobe level at the same aperture efficiency.

Chen J.,Guilin Air Force Academy | Yuan Y.,Guilin Air Force Academy | Yang J.,Guilin Air Force Academy
2010 The 2nd International Conference on Computer and Automation Engineering, ICCAE 2010 | Year: 2010

The shader in the GPU increases flexibility and enables customizations of vertex and fragment processing, and it also provides the programmer with various special effects essential in development of realistic 3D virtual scene. Compared to a CPU based simulation of the ocean water, the shader-based simulation in this paper reduces the complexity of the model by eliminating most fixed function parameters while giving access to the latest functionalities of graphics cards. Our water simulation is divided into four stages: wave generation, surface tessellation, optical simulation, and water surface rendering. We are satisfied with the result from implementing the respective stages's shader. ©2010 IEEE.

Luo H.,Guilin Air Force Academy | Tang Y.,Guilin Air Force Academy | Shen J.,Guilin Air Force Academy
Advanced Materials Research | Year: 2013

A mathematic model of capstan drive stiffness is presented. The influence of preload force, coefficient of friction, wraps of cable and load on the transmission stiffness of a differential cable-driven picking manipulator is analyzed. It is shown that capability of transmission, loads and precision can be considered comprehensively in the design of drive capstan. © (2013) Trans Tech Publications, Switzerland.

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