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Fractional Fourier domain equalization for single carrier broadband wireless systems

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Science china(Information Sciences) 2012年第10期55卷 2257-2268页

作者： HUANG KeWu 1,2,TAO Ran 1 & WANG Yue 1 1 Department of electronic engineering,beijing institute of technology,beijing 100081,china 2 institute of Manned Space System engineering,china Academy of Space technology,beijing 100094,china Department of electronic engineering Beijing Institute of Technology Beijing China institute of Manned Space System engineering China Academy of Space Technology Beijing China

In this paper,a novel single carrier equalization approach in the fractional Fourier domain(FRFD) is *** can remove all the inter-symbol interference(ISI) and avoid the considerable noise enhancement of the frequency domain-zero forcing(FD-ZF) *** the fractional Fourier transform makes a chirp spread,the impulse response of the deep fading channel may be flattened in some orders of the FRFD while it would be greatly attenuated in the *** searching for an optimal order under certain criterion,we take advantages of the ZF algorithm to mitigate the effects of the ISI *** approach can overcome the contradiction between the ISI mitigation and the noise enhancement of the FD-ZF *** analysis and simulation results show that the proposed FRFD-ZF equalizer can achieve a significant performance and have the same computation cost O(N log N) as the conventional FD linear equalizer,especially in the frequencyselective deep-fading channels.

关键词： fractional Fourier transform single carrier systems zero-forcing equalizer frequency domain linear equalizer

The discrete multiple-parameter fractional Fourier transform

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Science china(Information Sciences) 2010年第11期53卷 2287-2299页

作者： LANG Jun, TAO Ran& WANG Yue Department of electronic engineering, beijing institute of technology, beijing 100081, china Department of electronic engineering Beijing Institute of Technology Beijing China

As a generalization of the Fourier transform (FT), the fractional Fourier transform (FRFT) has many applications in the areas of optics, signal processing, information security, etc. Therefore, the efficient discrete computational method is the vital fundament for the application of the fractional Fourier transform. The multiple-parameter fractional Fourier transform (MPFRFT) is a generalized fractional Fourier transform, which not only includes FRFT as special cases, but also provides a unified framework for the study of FRFT. In this paper, we present in detail the discretization method of the MPFRFT and define the discrete multiple-parameter fractional Fourier transform (DMPFRFT). Then, we utilize the tensor product to define two-dimensional multiple-parameter fractional Fourier transform (2D-MPFRFT) and the corresponding two-dimensional discrete multiple-parameter fractional Fourier transform (2D-DMPFRFT). Finally, as an application, a novel image encryption method based on 2D-DMPFRFT is proposed. Numerical simulations are performed to demonstrate that the proposed method is reliable and more robust to blind decryption than several existing methods.

关键词： multiple-parameter fractional Fourier transform fractional Fourier transform image encryption information security

Research on distributed intrusion detection system based on multi-living agent

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Science china(Information Sciences) 2010年第5期53卷 1067-1077页

作者： WANG Yue, TAO Ran & ZHANG Hao Department of Information and electronic engineering, beijing institute of technology, beijing 100081, china Department of Information and electronic engineering Beijing Institute of Technology Beijing China

In this paper, we propose a novel distributed intrusion detection system based on multi-living agent inspired by the research method of multi-living agent complex information system for improving the security of distributed intrusion detection system using mobile agent. The previous two-layer distributed intrusion detection system has been expanded into a three-layer structure, the new layer of which can monitor the livelihood of each detection agent and utilize the negotiation-coordination mechanism to adjust the working way of each agent for protecting the security of system. In this paper, we propose a quantitative analysis method of agent livelihood in distributed intrusion detection system and further present the design method of living agent. Finally, through the analysis of system working flow and the detection effect of distributed denial of service attack, we have shown that the security and stability of the novel distributed intrusion detection system is effectively enhanced and the agent can work normally in strict restraint strong countermeasure environment.

关键词： multi-living mobile agent living agent lifecycle

On the TOPS mode spaceborne SAR

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Science china(Information Sciences) 2010年第2期53卷 367-378页

作者： BAI Xia 1 , SUN JinPing 2 , HONG Wen 3 & MAO ShiYi 2 1 Department of electronic engineering, beijing institute of technology, beijing 100081, china 2..epartment of electronic engineering, Beihang University , beijing 100191, china 3 institute of electronics,Chinese Academy of Sciences, beijing 100190, china Department of electronic engineering Beijing Institute of Technology Beijing China Department of electronic engineering Beihang University Beijing China institute of electronics Chinese Academy of Sciences Beijing China

TOPS (terrain observation by progressive scans) is a recently proposed SAR mode for wide swath acquisition, which aims at achieving the same coverage and resolution as the SCAN mode besides creating scalloping-free images. In this paper, a general SAR imaging model used in TOPS and other SAR modes is introduced, where the antenna sweep rate, Doppler centroid rate, illumination time and azimuth resolution are described by a parameter defined as the "mode factor". After analyzing the characteristics of TOPS signal, an algorithm based on chirp-z transform is proposed, in which a new de-rotation function is used. Simulation results validate the proposed algorithm.

关键词： synthetic aperture radar acquisition mode TOPS

Reconfigurable design and implementation of the MD6 Hash function

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The Journal of china Universities of Posts and Telecommunications 2010年第2期17卷 109-115页

作者： GAO Xian-wei Department of electronic and Information engineering,beijing electronic Science and technology institute,beijing 100070,china Department of electronic and Information engineering Beijing Electronic Science and Technology Institute Beijing 100070 China

Efficient reconfigurable field programmable gate array （FPGA） architectures for the MD6-224/256/384/512 Hash algorithm are proposed in this article. The basic iterative compact design requires 923 ALMs and achieves a throughput ranging from 225 Mbit/s to 394 Mbit/s at a maximum frequency of 198 MHz. The 32-step-urtrolled high-throughput design requires 7 090 ALMs and achieves a throughput ranges from 5 776 Mbit/s to 9 490 Mbit/s at a maximum frequency of 173 MHz. The simulation results show that high flexibility and efficient FPGA implementation of the MD6 Hash function is achieved.

关键词： SHA-3 MD6 reconfigurable iterative loop-unrolling

Theoretical observation of hexaatomic molecules containing pentacoordinate planar carbon

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Science china Chemistry 2008年第11期51卷 1030-1035页

作者： LUO Qiong State Key Laboratory of Explosion Science and technology, beijing institute of technology, beijing 100081, china State Key Laboratory of Explosion Science and technology Beijing Institute of Technology Beijing China

The smallest molecules up to date containing a D5h pentacoordinate planar carbon (PPC) atom, CBe5 and CBe54-, are presented by means of ab initio calculations. To gain a better understanding about which electronic factors contribute to their stabilization, natural bond orbital (NBO) analysis and the nucleus independent chemical shifts (NICS) were calculated. The data reported here suggest that D5h CBe5 is σ aromaticity in nature, while in D5h CBe54- π aromaticity is dominating. The classical octet rule is well satisfied in both molecules, and is one of the fundamental reasons to understand the stability of the pentagon structures. The Be5 ring serves as σ donor in D5h CBe5, and π-acceptor in D5h CBe54-. The D5h CBe54- possessing 18 valence electrons with a closed-shell electron configuration is the most plau-sible candidate for experimental detection.

关键词： pentacoordinate planar carbon Be5 ring ab initio

Statistic characteristic analysis of forward scattering surface clutter in bistatic radar

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Science china(Information Sciences) 2010年第12期53卷 2675-2686页

作者： HU Cheng ,LONG Teng & ZENG Tao Radar Research Lab,Department of electronic engineering,beijing institute of technology,beijing 100081,china Radar Research Lab Department of Electronic Engineering Beijing Institute of Technology Beijing China

In this paper,based on the processing results of measured forward scattering clutter data in bistatic radar,using the Gaussian distribution model,Exponential distribution model,Power-Law distribution model,high order Auto-Regressive model and so on,the probability density distribution and power spectrum mathematical model are obtained,and the impact of clutter statistic models on target detection performance is analytically derived from statistic *** to the estimated clutter probability distribution,power spectrum model and generalized matching filter theory,the forward scattering clutter in bistatic radar is effectively suppressed and the target motion parameters are accurately estimated from the measured clutter data.

关键词： bistatic radar forward scattering surface clutter clutter probability density function clutter power spectrum model target detection performance

Application of asymptotic waveform approximation technique to hybrid FE/BI method for 3D scattering

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Science in china(Series F) 2007年第1期50卷 124-134页

作者： PENG Zhen1,2,3 & SHENG XinQing2 1 institute of electronics, Chinese Academy of Sciences, beijing 100080, china 2..epartment of electronic engineering, beijing institute of technology, beijing 100081, china 3 Graduated University of Chinese Academy of Sciences, beijing 100039, china institute of electronics Chinese Academy of Sciences Beijing China Department of electronic engineering Beijing Institute of Technology Beijing China Graduated University of Chinese Academy of Sciences Beijing China

The asymptotic waveform evaluation （AWE） technique is a rational function approximation method in computational mathemetics, which is used in many appllcations in computational electromagnetlca. In this paper, the performance of the AWE technique in conjunction with hybrid finite element/boundary integral （FE/BI） method is firstly Inveetlgeted. The formuletlon of the AWE applied in hybrid FE/BI method is given in detail. The characteristic implementation of the application of the AWE to the hybrid FE/BI method is discussed. Numarlcel results demonstrate that the AWE technique can greatly speed up the hybrid FE/BI method to acquire wide-band and wide-angle backecatter radar-cross-section （RCS） by complex targets.

关键词： hybrid FE/BI AWE electromagnetic scattering RCS

Modeling and characteristic analysis of underwater acoustic signal of the accelerating propeller

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Science china(Information Sciences) 2012年第2期55卷 270-280页

作者： FENG Yuan1,2,TAO Ran1 & WANG Yue11Department of electronic engineering,beijing institute of technology,beijing 100081,china 2Science Research institute of china North Industries Group Corporation,beijing 100081,china Department of electronic engineering Beijing Institute of Technology Beijing China Science Research institute of china North Industries Group Corporation Beijing China

The signal feature of propeller cavitation noise during acceleration or deceleration procedure can be used to passively detect and classify moving vessels and underwater vehicles in the port *** analyzing the chirp periodicity of the variation of propeller wake velocity under acceleration situation,this paper presents a time domain expression of the modulation envelope signal of the accelerating propeller noise,treating the signal as a Gaussian-shaped chirp periodic pulse train with increasing trend and fluctuating pulse *** paper investigates the characteristics of simplified fractional Fourier transform(SFRFT)spectrum of the chirp periodic signal,and thus obtains the relation between the chirp periodic signal and its chirp harmonics under the conditions of underwater passive ***,the experimental data of the cavitation tunnel satisfy the results obtained by simulation,which verifies the correctness of the proposed signal model.

关键词： accelerating propeller modeling of underwater acoustic signal chirp periodic signal simplified fractional Fourier transform