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Adaptive stochastic resonance method for weak signal detection based on particle swarm optimization

Instrumentation 2015年第2期2卷 3-10页

作者： XING Hongyan ZHANG Qiang LU Chunxia Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science & Technology Key Laboratory of Meteorological Observation and Information Processing of Jiangsu Province Nanjing University of Information Science & Technology

In order to solve the parameter adjustment problems of adaptive stochastic resonance system in the areas of weak signal detection,this article presents a new method to enhance the detection efficiency and availability in the system of two-dimensional Duffing based on particle swarm ***,the influence of different parameters on the detection performance is analyzed *** correlation between parameter adjustment and stochastic resonance effect is also discussed and converted to the problem of multi-parameter ***,the experiments including typical system and sea clutter data are conducted to verify the effect of the proposed *** show that the proposed method is highly effective to detect weak signal from chaotic background,and enhance the output SNR greatly.

关键词： Adaptive stochastic resonance two-dimensional Duffing oscillator weak signal detection particle swarm optimization

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Hybrid inversion method for equivalent electric charge of thunder cloud based on multi-station atmospheric electric field

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Instrumentation 2015年第3期2卷 3-11页

作者： XING Hongyan ZHANG Qiang JI Xinyuan XU wei Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science & Technology Key Laboratory of Meteorological Observation and Information Processing of Jiangsu Province Nanjing University of Information Science & Technology

This article proposes the hybrid method to inverse the equivalent electric charge of thunder cloud based on the data of multi-station atmospheric electric field. Firstly,the method combines the genetic algorithm( GA) and New ton method through the mosaic hybrid structure. In addition,the thunder cloud equivalent charge is inversed based on the forw ard modeling results by giving the parameters of the thunder cloud charge structure. Then an ideal model is built to examine the performance compared to the nonlinear least squares method. Finally,a typical thunderstorms process in Nanjing is analyzed by Genetic-New ton algorithm with the help of weather radar. The results show the proposed method has the strong global searching capability so that the problem of initial value selection can be solved effectively,as well as gets the better inversion results. Furthermore,the mosaic hybrid structure can absorb the advantages of tw o algorithms better,and the inversion position is consistent with the strongest radar *** inversion results find the upper negative charge is small and can be ignored,w hich means the triple-polarity charge structure is relatively scientific,w hich could give some references to the research like lightning forecasting,location tracking.

关键词： inversion of thunder cloud equivalent charge atmospheric electric field genetic algorithm new ton method

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Flooding and node-wise RBP sequentially concatenated decoder for LDPC codes

Flooding and node-wise RBP sequentially concatenated decoder...

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IEEE International Conference on Communications in China (ICCC)

作者： Hua Zhou Peng Li Jiao Feng Bo Ni Jiangsu Key Laboratory of Meteorological Observation and Information Processing Nanjing University of Information Science and Technology Nanjing China

A new strategy of belief propagation (BP) decoder for LDPC codes is presented by sequentially concatenating the scheduling algorithms of flooding and node-wise residual belief propagation (NW RBP) without increasing the complexity of hardware implementation. Compared to NW RBP, the concatenated BP decoder significantly decreases the decoding latency caused by computing and sorting the residual of each message in the factor graph of an LDPC code. As the signal-to-noise ratio (SNR) increases, the decoding performance of the concatenated BP decoder outperforms that of purely applying flooding or NW RBP, and the average number of decoding iterations required for the concatenated decoder decreases and tends to be approximately the same as the other two.

关键词： Iterative decoding Decoding Bit error rate Belief propagation Signal to noise ratio Convergence

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Influence of defects on the young's modulus of silicon nanowires with different cross sections

Influence of defects on the young's modulus of silicon nano...

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16th Annual Conference and 5th International Conference on Chinese Society of Micro-Nano Technology, CSMNT 2014

作者： Gu, Fang Zhang, Jiahong Li, Min Liu, Linyan Su, Jing School of Physics and Optoelectronic Engineering Nanjing University of Information Science and Technology Nanjing China Jiangsu Collaborative Innovation Center on Atmospheric Environment and Equipment Technology Nanjing University of Information Science and Technology Nanjing210044 China Jiangsu Key Laboratory of Meteorological Observation and Information Processing Nanjing University of Information Science and Technology Nanjing China

ISBN: (纸本)9783038354628

The size dependence becomes more significant as the devices scale down from micro- to nano-dimensions, which is generally attributed to surface effects due to the very high surface-to-bulk ratios in nanoscale structures. However, significant discrepancies between experimental measurements and computational studies indicate that there could be other influences besides surface effects, such as the influences of native oxide layer, fabrication-induced defects and boundary conditions. In this paper, our purpose is to investigate mainly the influence of fabrication-induced defects on the elasticity of [110] silicon nanowires (SiNWs) with different cross sections. We accomplish this by using the molecular dynamics (MD) simulation. Our MD results show that the H-passivated [110] SiNWs without surface defects is slightly elastically softer than bulk, which is in good agreement with other literature MD values. However, the effective Young's modulus of SiNWs with surface defects can significantly decreases as the defects increase. This softening behavior of [110] SiNWs is severe, which indicates the importance of surface defects. It is noted that the influence of defects on the Young's Modulus of SiNWs strongly depended on the distribution and morphology of defects as well as the cross-sectional shapes of SiNWs. It is observed that the influence of defects on square SiNWs is significantly different from those of hexagonal and triangle SiNWs. Our work reveals that fabrication-induced surface defects could be one of the important origins of the reduced effective Young's modulus experimentally observed in ultra-thin SiNWs. Therefore, the effect of defects on the characterization of the mechanical properties of nanowire must be carefully considered. © (2015) Trans Tech Publications, Switzerland.

关键词： Elastic moduli

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Effect of undercut on the characterization of the mechanical properties of silicon nanocantilevers with dynamic and static test

Effect of undercut on the characterization of the mechanical...

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16th Annual Conference and 5th International Conference on Chinese Society of Micro-Nano Technology, CSMNT 2014

作者： Zhang, Jiahong Gu, Fang Zhang, Xianling Li, Min Ge, Yixian Mao, Xiaoli Jiangsu Key Laboratory of Meteorological Observation and Information Processing Nanjing University of Information Science and Technology Nanjing210044 China Jiangsu Collaborative Innovation Center on Atmospheric Environment and Equipment Technology Nanjing University of Information Science and Technology Nanjing210044 China School of Physics and Optoelectronic Engineering Nanjing University of Information Science and Technology Nanjing210044 China

ISBN: (纸本)9783038354628

The elastic mechanical properties of silicon nanocantilevers are of prime importance in biotechnology and nanoelectromechanical system (NEMS) applications. In order to make these applications reliable, the exact evaluation of the effect of the undercut on the mechanical properties of silicon nanocantilevers is essential and critical. In this paper, a numerical-experimental method for determining the effect of the undercut on resonant frequencies and Young's modulus of silicon nanocantilevers is proposed by combining finite element (FE) analysis and dynamic frequency response tests by using laser Doppler vibrometer (LDV) as well as static force-displacement curve test by using an atomic force microscope (AFM). Silicon nanocantilevers test structures are fabricated from silicon-on-insulator (SOI) wafers by using the standard complementary metal-oxide-semiconductor (CMOS) lithography process and anisotropic wet-etch release process based on the critical point drying, which inevitably generating the undercut of the nanocantilever clamping. Combining with three-dimensional FE numerical simulations incorporating the geometric undercut, the dynamic resonance tests demonstrate that the undercut obviously reduces resonant frequencies of nanocantilevers due to the fact that the undercut effectively increases the nanocantilever length by a correct value ΔL. According to a least-square fit expression including ΔL, we extract Young's modulus from the measured resonance frequency versus the effective length dependency and find that Young's modulus of a silicon nanocantilever with 200-nm thickness is close to that of bulk silicon. However, when we do not consider the undercut ΔL, the obtained Young's modulus is decreased 39.3%. Based on the linear force-displacement response of 12μm long and 200nm thick silicon nanocantilever obtained by using AFM, our extracted Young's modulus of the [110] nanocantilever with and without undercut is 169.1GPa and 133.0GPa, respectively. This error

关键词： Finite element method

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Four-element dual-band MIMO antenna system for mobile phones

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Progress In Electromagnetics Research C 2015年 60卷 47-56页

作者： Yang, Lingsheng Xu, Hongling Fang, Jianping Li, Tao The Jiangsu Key Laboratory of Meteorological Observation and Information Processing and Research Center of Applied Electromagnetics of NUIST Nanjing University of Information Science and Technology NingLiu Road Nanjing210044 China

Adual-band multiple-input-multiple-output (MIMO) antenna system for LTE 700/2300/2500, UMTS2100, GSM 1800/1900 mobile phone applications is presented. The whole system consists of four identical 3-D IFAs (inverted F antenna) loaded with lumped inductors and folded on FR4 cuboids. Without any special designed decoupling structures, the measured isolation among antenna elements is higher than 13 dB. Return loss characteristics, correlation coefficient, gain and radiation performance are also presented. © 2015, Electromagnetics Academy. All rights reserved.

关键词： Cellular telephones

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Short text classification algorithm based on semi-supervised learning and SVM

International Journal of Multimedia and Ubiquitous Engineeri...

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International Journal of Multimedia and Ubiquitous Engineering 2015年第12期10卷 195-206页

作者： Yin, Chunyong Xiang, Jun Zhang, Hui Yin, Zhichao Wang, Jin Jiangsu Key Laboratory of Meteorological Observation and Information Processing School of Computer and Software Jiangsu Engineering Center of Network Monitoring Nanjing University of Information Science and Technology Nanjing China Nanjing No.1 Middle School NanjingJiangsu China

Short text is a popular text form, which is widely used in real-time network news, short commentary, micro-blog and many other fields. With the development of the application such as QQ, mobile phone text messages and movie websites, the size of data is also becoming larger and larger. Most data is useless for us while other data is significant for us. Therefore, it is necessary for us to extract the useful short text from the big data. However, there are many problems with the short text classification, such as fewer features, irregularity and so on. To solve these problems, we should pretreat the short text set first, and then choose the significant features. This paper use semi-supervised learning method and SVM classifier to improve the traditional methods and it can classify a large number of short texts to mining the useful massage from the short text. The experimental results in this paper also show a good promotion. © 2015 SERSC.

关键词： Supervised learning

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A feature selection algorithm towards efficient intrusion detection

International Journal of Multimedia and Ubiquitous Engineeri...

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International Journal of Multimedia and Ubiquitous Engineering 2015年第11期10卷 253-264页

作者： Yin, Chunyong Ma, Luyu Feng, Lu Yin, Zhichao Wang, Jin School of Computer and Software Jiangsu Key Laboratory of Meteorological Observation and Information Processing Jiangsu Engineering Center of Network Monitoring Nanjing University of Information Science and Technology Nanjing China Nanjing No.1 Middle School Nanjing China

Feature selection algorithm plays a crucial role in intrusion detection, data mining and pattern recognition. According to some evaluation criteria, it gets optimal feature subset by deleting unrelated and redundant features of the original data set. Aiming at solving the problems about the low accuracy, the high false positive rate and the long detection time of the existing feature selection algorithm. In this paper, we come up with a feature selection algorithm towards efficient intrusion detection, this algorithm combines the correlation algorithm and redundancy algorithm to chooses the optimal feature subset. Experimental results show that the algorithm shows almost and even better than the traditional feature selection algorithm on the different classifiers. © 2015 SERSC.

关键词： Redundancy

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Linearization method of carrier catalytic gas sensor characteristics using high-order polynomial

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Open Automation and Control Systems Journal 2015年第1期7卷 415-420页

作者： Weiyong, Huang Yuqing, Gao Xiuling, Tian Xuzhou Key Laboratory of Virtual Reality and Multi-dimensional Information Processing Xuzhou Institute of Technology Xuzhou Jiangsu221111 China Jiangsu Key Laboratory of Large Engineering Equipment Detection and Control Xuzhou Institute of Technology Xuzhou Jiangsu221111 China School of Information and Electrical Engineering Xuzhou Institute of Technology Xuzhou Jiangsu221111 China

To improve detecting performance of gas concentration in coal-mine, a new linearization method of carrier catalytic gas sensor characteristics based on high-order polynomials was introduced. Firstly, the calibration data of sensor was used to establish the training sample set. Then, the high-order polynomial was employed to establish nonlinear regression inverse model of sensor characteristics. Finally, the polynomial coefficients were intelligently tuned by improved clone selection algorithm (ICSA) and the criteria of mean absolute error (MAE) minimization. Experimental results showed the the method proposed in this paper is effective, and the performance of inearization model is superior to that of the traditional least square method. © Weiyong et al.;Licensee Bentham Open.

关键词： Coal mines

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Experimental investigations on new characterization method for giant piezoresistance effect and silicon nanowire piezoresistive detection

Experimental investigations on new characterization method f...

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16th Annual Conference and 5th International Conference on Chinese Society of Micro-Nano Technology, CSMNT 2014

作者： Zhang, Jiahong Yang, Min Liu, Qingquan Gu, Fang Li, Min Ge, Yixian Jiangsu Key Laboratory of Meteorological Observation and Information Processing Nanjing University of Information Science and Technology Nanjing210044 China Jiangsu Collaborative Innovation Center on Atmospheric Environment and Equipment Technology Nanjing University of Information Science and Technology Nanjing210044 China School of Electronic and Information Engineering Nanjing University of Information Science and Technology Nanjing210044 China School of Physics and Optoelectronic Engineering Nanjing University of Information Science and Technology Nanjing210044 China

ISBN: (纸本)9783038354628

This paper presents a novel and effective characterization method for giant piezoresistive properties of silicon nanowires by using the reference structures. This contrast detection approach investigates the influences of quantum size effect and surface defects effect on piezoresistive coefficients of silicon nanowires by direct comparison of the resistivity change ratio of silicon wires with nanoscale-to-microscale width under the same applied stress conditions. The characterization experiments based on four-point bending tensile test demonstrate that piezoresistive coefficient of small nano-width silicon nanowire can be significantly increased to about five times higher levels than that of bulk silicon under the same impurity concentration, which indicates that the silicon nanowire can have giant piezoresistive effect. On the other hand, to solve the problem on nanowires pick-up, we proposed a nanowire piezoresistive detection approach, whose validity is confirmed by the dynamic LDV resonance test. Meanwhile, to investigate the influence of undercut arising from the wet chemical release process of the suspended silicon nanowire, a three-dimensional finite element simulation is also carried out for the fundamental resonant frequency using ANSYS software. The numerical and experimental results show that our piezoresistive detection is accurate and effective and the undercut should be carefully considered in the design of the high frequency resonator and mixer. The findings of this paper provide some useful references for the piezoresistive effect measurement and the piezoresistive pick-up in nanoelectromechanical system. © (2015) Trans Tech Publications, Switzerland.

关键词： Nanowires

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