Huang H.,Ordnance Engineering College |
Du Q.,Xi'an Research Institute of High Technology |
Kang X.,Ordnance Engineering College
ISA Transactions | Year: 2013
In this paper, a class of neutral high-order stochastic Hopfield neural networks with Markovian jump parameters and mixed time delays is investigated. The jumping parameters are modeled as a continuous-time finite-state Markov chain. At first, the existence of equilibrium point for the addressed neural networks is studied. By utilizing the Lyapunov stability theory, stochastic analysis theory and linear matrix inequality (LMI) technique, new delay-dependent stability criteria are presented in terms of linear matrix inequalities to guarantee the neural networks to be globally exponentially stable in the mean square. Numerical simulations are carried out to illustrate the main results. © 2013 ISA. Published by ISA. All rights reserved. Research Article.
Li H.,Shijiazhuang Railway Institute |
Zheng H.,Ordnance Engineering College |
Tang L.,Ordnance Engineering College
Zhendong Ceshi Yu Zhenduan/Journal of Vibration, Measurement and Diagnosis | Year: 2013
According to the shortcomings of traditional dual-tree complex wavelet transform which has spectral aliasing, a novel approach to multi-faults diagnosis of bearing based on improved dual-tree complex wavelet transform is presented. Firstly, the bearing fault vibration signals are decomposed into various frequency band signals. Then the band signals are decomposed using empirical mode decomposition technique, and the maximum energy component is found. In the end, the envelope spectrum of maximum energy components is computed. Therefore, the characteristics of the bearing faults can be recognized according to the envelope spectrum. The simulative and experimental results show that not only the spectral aliasing is eliminated, but also the frequency band selection accuracy and signal noise ratio are improved, the multi-faults of the bearing can be effectively detected.
Li H.,Shijiazhuang Railway Institute |
Zheng H.-Q.,Ordnance Engineering College |
Tang L.-W.,Ordnance Engineering College
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2012
Morphological component analysis (MCA) is a signal-or image-processing method based on signal morphological diversity and sparse representation. MCA takes advantage of the sparse representation of the analyzed data in over-complete dictionaries to separate features of the data based on their morphology. Aiming at shortcomings of traditional morphological component analysis about dictionary selection and threshold selection, an improved approach to MCA combining adaptive dictionary selection and hard threshold MOM strategy was proposed. The simulation and experimental results showed that with the proposed method, not only a signal with morphological diversity can be separated, but also the signal noise ratio of the separated signal can be improved, the multi-fault of the bearing of a gearbox can be effectively detected.
Gao H.C.,Ordnance Engineering College
Advanced Materials Research | Year: 2013
Due to the emergence of more and more composite armor target, the research related with interval has real application background. The target board with interval structure form attenuates jet penetration effectively. If the interval target and homogeneous target can build equivalent relations, with a certain thickness of the interval target equivalent instead of a homogeneous target board, it will slash test cost and save money. After the target principle and research method, the jet penetration interval target for energy consumption, the jet penetration depth interval target researches are simple introduced, finally the research direction of interval target is put forward with own suggestions. © (2013) Trans Tech Publications, Switzerland.
Li J.,Ordnance Engineering College
Guangdian Gongcheng/Opto-Electronic Engineering | Year: 2010
The mechanism of precision tracking turntable was designed. The entity model of the precision optoelectronic tracking turntable frame was established and the static and dynamic analysis of the precision turntable was done by using the software ANSYS. The static analysis results show that the intensity and rigid requirements of tracking turntable frame were satisfied. The mode analysis indicated that the precision optoelectronic tracking turntable frame had good dynamic characteristics, and synonym did not occur. The rationality of turntable frame was validated by analysis results, and it provided the important evidence for the optimization design of precision optoelectronic tracking turntable.
Zhang K.,Ordnance Engineering College |
Shan G.,Ordnance Engineering College
Yi Qi Yi Biao Xue Bao/Chinese Journal of Scientific Instrument | Year: 2014
To improve filtering result of square-root cubature Kalman filter (SCKF) under non-Gaussian condition, a Gaussian sum square-root cubature Kalman filter (GSSCKF) algorithm is developed based on analyzing SCKF and Gaussian sum filter (GSF). The new algorithm uses the form of Gaussian sum to approximate the non-Gaussian posterior probability density, takes SCKF as the Gaussian sub-filter to realize time and measurement update for each Gaussian component, the algorithm can effectively deal with nonlinear non-Gaussian filtering problem. Simulation results show that the accuracy of GSSCKF is higher than particle filter (PF) and Gaussian sum extended Kalman filter (GSEKF). Compared with cubature particle filter (CPF), the precision is similar, but the consuming time of GSSCKF is about 15% of CPF. GSSCKF performs well in term of the balance between the tracking accuracy and the real-time. ©, 2014, Science Press. All right reserved.
Kong D.,Ordnance Engineering College |
Shen X.,Ordnance Engineering College
Optics and Laser Technology | Year: 2014
A multiple-image encryption scheme based on the optical wavelet transform (OWT) and the multichannel fractional Fourier transform (MFrFT) is proposed. The scheme can make full use of multi-resolution decomposition of wavelet transform (WT) and multichannel processing of MFrFT. The mentioned properties can achieve the encryption of multi-image and the encryption of single image. When encryption finished, each image gets its own fractional order and independent keys. Analysis of encrypted effects has been completed. Furthermore, the influence of WT type and order are analyzed, and the application and analysis of MFrFT are accomplished as well. Numerical simulation verifies the feasibility of the scheme and shows that the problem of insufficient capacity is better solved, and the flexibility of scheme increases. A simple opto-electronic mixed device to realize the scheme is proposed. © 2013 Published by Elsevier Ltd. All rights reserved.
Lv B.,Ordnance Engineering College
2010 International Conference on Computer Design and Applications, ICCDA 2010 | Year: 2010
A new active jamming technique to synthetic aperture radar (SAR) is analyzed, which is called noise convolution jamming technique, or smart noise jamming technique. This technique can receive part of the SAR's process gains, so it is superior to current noise blanketing styles. It can reduce the jamming energy and improve the utility of jamming power greatly. By selecting the noise signal's initial time and terminal time, we can control the position and width of the jamming region in order to suppress distributed targets. Theoretical analysis and computer simulation justify the validity and efficiency of the new jamming technique. © 2010 IEEE.
Lu C.-H.,Ordnance Engineering College |
Bai H.-B.,Ordnance Engineering College
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2011
By means of analyzing vibration isolation mechanism of combined positive stiffness and negative one, a new type ultra-low passive vibration isolation system was designed here. The combination of negative stiffness mechanism and positive stiffness spring was used in this isolator so that it possessed higher supporting stiffness and ultra-low vibration stiffness, and its stiffness revealed nonlinear characteristics. This system solved the problem of ultra-low frequency vibration isolation in traditional passive vibration isolators. By analyzing the mechanical characteristics of this system, the expressions for the stiffness of the system and the zero stiffness condition of the system at the equilibrium position were deduced, they offered theoretical guides for designing new type nonlinear ultra-low frequency vibration isolators.
Lu B.,Ordnance Engineering College
Dianbo Kexue Xuebao/Chinese Journal of Radio Science | Year: 2013
Aiming at the problem of target effect in sidelobe canceller, polarization filtering technique based on oblique projection operator is introduced into sidelobe cancellation system, and a new method to eliminate target effect is presented. This new method estimates jamming signal polarization parameters, and calculates oblique projection operator; The calculated oblique projection operator acts on accessory channel echo, as a result, the jamming signal extracted from the echo and target signal is entirely rejected. Compared with normal polarization filtering methods, this new method can reject target signal entirely and improve cancellation ratio greatly, only jamming signal polarization parameters needed. Theory analysis and computer simulation prove the validity of this method. © 2013 by Editorial Department of Chinese Journal of Radio Science.