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Dynamics of electron in a surface quantum well

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Chinese Physics B 2009年第6期18卷 2523-2528页

作者：王立飞杨光参 School of Physics and Electronic Information Wenzhou University

This paper studies the quantum dynamics of electrons in a surface quantum well in the time domain with auto- correlation of wave packet. The evolution of the wave packet for different manifold eigenstates with finite and infinite lifetimes is investigated analytically. It is found that the quantum coherence and evolution of the surface electronic wave packet can be controlled by the laser central energy and electric field. The results show that the finite lifetime of excited states expedites the dephasing of the coherent electronic wave packet significantly. The correspondence between classical and quantum mechanica is shown explicitly in the system.

关键词： quantum well electronic wavepacket autocorrelation function

LONG-RANGE CORRELATIONS IN DNA SEQUENCES USING TWO-DIMENSIONAL DNA WALKS

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Chinese Journal of Polymer Science 2005年第1期23卷 11-16页

作者： JinChena Lin-xiZhanga De-luZhaob DepartmentofPhysics WenzhouNormalCollegeWenzhou325027China PolymerPhysicsLaboratory CenterofMolecularScienceInstituteofChemistryChineseAcademyofSciencesBeijing100080China

The characterization of long-range correlations and fractal properties of DNA sequences has proved to be adifficult though rewarding task mainly due to the mosaic character of DNA consisting of many patches of various lengthswith different nucleotide *** this paper we investigate statistical correlations among different positions in DNAsequences using the two-dimensional DNA *** root-mean-square fluctuation F(l)is described by a power *** function C(l),which is used to measure the linear dependence and periodicity,exists a power law ofC(l)-l^(-μ).We also calculate the mean-square distancealong the DNA chain,and it may be expressed as-l^(?)with 2>γ>*** investigations can provide some insights into long-range correlations in DNA sequences.

关键词： autocorrelation function DNA sequence Long-range correlation.

Chaos game representation walk model for the protein sequences

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Chinese Physics B 2009年第10期18卷 4571-4579页

作者：高洁蒋丽丽徐振源 School of Science Jiangnan University School of Information Technology Jiangnan University

A new chaos game representation of protein sequences based on the detailed hydrophobic-hydrophilic （HP） model has been proposed by Yu et al （Physica A 337（2004） 171）. A CGR-walk model is proposed based on the new CGR coordinates for the protein sequences from complete genomes in the present paper. The new CCR coordinates based on the detailed HP model are converted into a time series, and a long-memory ARFIMA（p, d, q） model is introduced into the protein sequence analysis. This model is applied to simulating real CCR-walk sequence data of twelve protein sequences. Remarkably long-range correlations are uncovered in the data and the results obtained from these models are reasonably consistent with those available from the ARFIMA（p, d, q） model.

关键词： chaos game representation CGR-walk model protein sequence long-memory ARFIMA(p d q) model autocorrelation function

De-noising of radiation pressure signal generated by bubble oscillation based on ensemble empirical mode decomposition

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Journal of Hydrodynamics 2022年第5期34卷 849-863页

作者： Xiang-hao Zheng Yu-ning Zhang Key Laboratory of Power Station Energy Transfer Conversion and System(Ministry of Education) School of EnergyPower and Mechanical EngineeringNorth China Electric Power UniversityBeijing102206China

The radiation pressure signals generated by the bubble oscillation are often utilized to recognize the characteristics of the target objects in many ***,these signals are easily contaminated by complex background *** order to accurately extract the effective components of the radiation pressure signal generated by the bubble oscillation,this paper proposes a de-noising procedure for the radiation pressure signal,based on the ensemble empirical mode decomposition(EEMD),the autocorrelation function and the modified wavelet soft-threshold de-noising *** order to verify the effectiveness of the procedure,the typical radiation pressure signal generated based on the Keller-Miksis model under the acoustic excitation is employed for the subsequent de-noising *** results of the qualitative analysis show that the amplitude and the period of the bubble oscillation can be clearly observed in the time-domain diagram of the de-noised signal based on the *** the quantitative analysis,the de-noised signal based on the EEMD has better performance with higher signal-to-noise ratio(SNR),smaller root-mean-square error,and larger correlation coefficient than that based on the wavelet transform(WT)and the empirical mode decomposition(EMD).Furthermore,with the increase of the complexity of the radiation pressure signal(e.g.,the increase of the dimensionless pressure amplitude of the acoustic wave and the decrease of the SNR of the input signal),the above three evaluation indexes of the de-noised signal based on the EEMD are all better than those based on the other two *** the signal is more complex,the de-noising capabilities of the WT,the EMD are greatly reduced,but the EEMD can still maintain the good de-noising capability,which shows the superiority of the signal de-noising procedure proposed in the present paper.

关键词： Radiation pressure cavitation bubble oscillation signal de-noising ensemble empirical mode decomposition(EEMD) autocorrelation function wavelet soft-threshold de-noising

Detecting P2P bots by mining the regional periodicity

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Journal of Zhejiang University-Science C(Computers and Electronics) 2013年第9期14卷 682-700页

作者： Yong QIAO Yue-xiang YANG Jie HE Chuan TANG Ying-zhi ZENG College of Computer National University of Defense Technology Information Center National University of Defense Technology

Peer-to-peer (P2P) botnets outperform the traditional Internet relay chat (IRC) botnets in evading detection and they have become a prevailing type of threat to the Internet *** methods for detecting P2P botnets,such as similarity analysis of network behavior and machine-learning based classification,cannot handle the challenges brought about by different network scenarios and botnet *** noticed that one important but neglected characteristic of P2P bots is that they periodically send requests to update their peer lists or receive commands from botmasters in the command-and-control (C&C) *** this paper,we propose a novel detection model named detection by mining regional periodicity (DMRP),including capturing the event time series,mining the hidden periodicity of host behaviors,and evaluating the mined periodic patterns to identify P2P bot *** our detection model is built based on the basic properties of P2P protocols,it is difficult for P2P bots to avoid being detected as long as P2P protocols are employed in their C&*** hidden periodicity mining,we introduce the so-called regional periodic pattern mining in a time series and present our algorithms to solve the mining *** experimental evaluation on public datasets demonstrates that the algorithms are promising for efficient P2P bot detection in the C&C phase.

关键词： P2P botnet detection Regional periodicity Apriori autocorrelation function Evaluation function

Constructions of Balanced Quaternary Sequences

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Chinese Journal of Electronics 2020年第3期29卷 463-467页

作者： WANG Jingjing ZHAO Min YANG Zhiyao GUO Yuyan ZHUO Zepeng School of Mathematical Sciences Huaibei Normal University School of Computer Science and Technology Huaibei Normal University

Binary and quaternary sequences have received a lot of attention since they are easy to be implemented as multiple-access sequence in practical communication systems, radar, and cryptography. In this paper, the two complete binary sequence of period N are analyzed. For odd prime N, new balanced quaternaruy sequences of even period 2 N are constructed using Gary mapping. Furthermore, we computer the complete autocorrelation distributions of this sequence.

关键词： Binary sequence Balance Quaternary sequence autocorrelation function

Effect of chip rate on the ranging accuracy in a regenerative pseudo-noise ranging system

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Journal of Zhejiang University-Science C(Computers and Electronics) 2011年第2期12卷 132-139页

作者： Jian-wen JIANG Wei-jun YANG Chao-jie ZHANG Xiao-jun JIN Zhong-he JIN Department of Information Science and Electronic Engineering Zhejiang University Hangzhou 310027 China

The ranging accuracy of a pseudo-noise ranging system is mainly decided by range jitter and time delay discrimination. Many factors can affect the ranging accuracy, one of which is the chip rate. In digital signal processing, the time delay discrimination and autocorrelation function of sampled ranging sequences of different chip rates are very different. An approximation simulation model is established according to an in-phase quadrature (I/Q) correlator which is used to evaluate the time delay. Simulation results of the range jitter and time delay discrimination show that the chip rate which provides a non-integer sample-to-chip rate ratio can achieve a higher ranging accuracy, and some test results validate the simulation model. In some design missions, the simulation results may help to select an optimum sample-to-chip rate ratio to satisfy the design requirement on the ranging accuracy.

关键词： Ranging accuracy Range jitter Time delay discrimination Sample-to-chip rate ratio Integration time autocorrelation function Fractional chip period delay

Frequency invariability of acoustic field and passive source range estimation in shallow water

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Science China(Physics,Mechanics & Astronomy) 2014年第2期57卷 225-232页

作者： ZHOU ShiHong QI YuBo REN Yun State Key Laboratory of Acoustics Institute of AcousticsChinese Academy of Sciences

The frequency invariability of the warped modal signal and the warped signal autocorrelation function in shallow water is discussed.A method is proposed for passive source-range estimation based on the frequency invariability and warping transform of signal autocorrelation function received by a single hydrophone in a range-independent or weak range-dependent shallow water *** the method,a guided source with a known range is employed to provide the crucial and relative invariant scaled *** experimental data in shallow water with an iso-speed profile and a fluctuated thermocline are used to verify this *** relative errors of the source range estimation are basically less than 10%.

关键词： frequency invariability warping transform autocorrelation function passive range estimation single hydrophone

IDFT Numerical Simulation Method for Gaussian Rough Surface with Relatively Large Correlation Length

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Transactions of Tianjin University 2015年第3期21卷 216-222页

作者：王廷剑王黎钦赵小力 School of Mechatronics Engineering Harbin Institute of Technology

A numerical simulation method based on inverse discrete Fourier transform(IDFT)is presented for generating Gaussian rough surface with a desired autocorrelation function(ACF). The probability density function of the height distribution of the generated Gaussian surface and the root-mean-square height of the rough surface are also considered. It is found that the height distribution of the generated surface follows the Gaussian distribution, the deviation of the root-mean-square height of the modeled rough surface from the desired value is smaller than that of Patir's method, and the autocorrelation function of the modeled surface is also in good agreement with the desired autocorrelation function. Compared with Patir's method, the modeled surface generated by the IDFT method is in better agreement with the desired autocorrelation function, especially when the correlation length is relatively large.

关键词： numerical simulation Gaussian rough surface autocorrelation function root-mean-square height IDFT