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Optimal user scheduling and power control in multi-user cognitive broadcast systems

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Science china(information Sciences) 2012年第6期55卷 1402-1414页

作者： WANG QunHuan 1,2,3,WANG HuiMing 1,2,3 & YIN QinYe 1,3 1 School of Electronic and information Engineering,xi'an Jiaotong univ.rsity,xi'an 710049,china 2 State Key Lab for Integrated Services Networks,xidian univ.rsity,xi'an 710071,china 3 Ministry of Education Key Lab for intelligent Networks and Network Security,xi'an Jiaotong univ.rsity,xi'an 710071,china. 1. School of Electronic and information Engineering Xi’an Jiaotong University Xi’an 710049 China2. State Key Lab for Integrated Services Networks Xidian University Xi’an 710071 China3. Ministry of Education Key Lab for Intelligent Networks and Network Security Xi’an Jiaotong University Xi’an 710071 China

Cognitive radio systems should not only have the ability to sense and exploit "frequency spectrum holes",but also the ability to sense and utilize "spatial spectrum holes".In this paper,we consider the issue of maximizing the throughput of the cognitive systems by fully utilizing "spatial spectrum holes" brought in by multiple cognitive users,in the scenario where a pair of licensed users and a cognitive broadcast system share multiple spectrum *** exploiting the channel reciprocity under the premise that the licensed system adopts the time-division-duplexing (TDD) mode,we propose a more practical cognitive access scheme that can sense the interference at the licensed user caused by the cognitive transmitter,based on the existing feedback signals from the licensed user to the licensed base *** both interferences from the licensed base station to the cognitive receiver and from the cognitive transmitter to the licensed user into consideration,we investigate the optimal user scheduling and power allocation scheme that can maximize the ergodic sum rate of the cognitive *** show that scheduling the user whose channel gain to interference and noise ratio (CGINr) is the largest for each frequency band is *** also derive the dynamic power allocation scheme meeting the three practical constraints,i.e.,the transmitter's average transmission power constraint,the power amplifier's instantaneous transmission power constraint,and the interference power constraint at the licensed *** result shows that in different coherent time intervals and different frequency bands,the power allocation has a multi-level waterfilling *** analysis shows that the strategy scheduling user with the largest CGINr introduces significant performance improvement compared with the traditional strategy scheduling user with the largest channel gain to noise ratio (CGNr).We also illustrate the impact of power constraints and the number of users on system p

关键词： cognitive radio distributed spatial spectrum holes opportunistic scheduling power allocation

Double-characters detection of nonlinear frequency modulated signals based on FrFT

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Science china(information Sciences) 2011年第1期54卷 136-145页

作者： XU ShuWen,SHUI pengLang & YANG xiaoChao National Laboratory of radar Signal processing,xidian univ.rsity,xi’an 710071,china 1. National Laboratory of radar Signal processing Xidian University Xi’an 710071 China

In many practical applications,signals to be detected are unknown nonlinear frequency modulated (FM)and are corrupted by strong *** phase histories of the nonlinear FM signals are assumed to be unknown smooth functions of time,which are usually poorly modeled or cannot be modeled at all by a small number of *** of the lack of phase model,a nonparametric detection method is proposed based on successive fractional Fourier transform and double-characters *** detection process goes in three ***,an image is constructed by the fractional Fourier transforms of successive angles in one period. Then,the threshold procedure is utilized to transform the image into a binary *** the multiple median filtering,the binary image is refined where the isolated noise pixels are ***,two complementary features are extracted from the refined image,and a double-characters detector is proposed to decide whether the target is present or *** simulation experiments to three polynomial phase signals with different orders and a sinusoidal phase signal show that the proposed detection method is effective and robust.

关键词： fractional Fourier transform double-characters detector nonparametric detection multiple median filtering

An eigenstructure-based 2D DOA estimation method using dual-size spatial invariance array

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Science china(information Sciences) 2011年第1期54卷 163-171页

作者： YANG XueYa,CHEN Baixiao & CHEN YunHai National Key Lab of radar Signal processing,xidian univ.rsity,xi’an 710071,china 1. National Key Lab of radar Signal processing Xidian University Xi’an 710071 China

A sparse planar array vertically placed in y-z plane is proposed to improve the angle estimation accuracy of sources in low angle region with reflection *** two sizes of spatial invariances along both dimensions,the array estimates the azimuth and elevation angles using unitary ESprIT(estimation of signal parameters via rotational invariance techniques).The first spatial invariance with a displacement of half-wavelength yields unambiguous coarse estimates of high-variance,while the second spatial invariance with much larger a displacement of subarrays obtains cyclically ambiguous fine estimates of *** final estimates are obtained by disambiguating fine estimates with coarse estimates.A novel pairing scheme is proposed to pair both the azimuth and elevation,coarse and fine angle estimates of the same *** addition, a new method is presented to calculate 2D angles,which substitutes the estimated elevation angle into the sin relative to the y-axis to get the azimuth *** real-valued processing and array aperture extension, the new DOA measuring method de-correlates the multipath signals and enhances angle resolution with no extra antennas and computational *** results show the effectiveness of the proposed technique and its advantages over the conventional methods.

关键词： DOA estimation sparse array correlated signals unitary ESprIT dual-size spatial invariances

A novel algorithm of artificial immune system for high-dimensional function numerical optimization

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progress in Natural Science:Materials International 2005年第5期15卷 463-471页

作者： DU Haifeng 1,2*, GONG Maoguo1, JIAO Licheng1 and LIU ruochen1(1. institute of intelligent information processing and Key Laboratory of radar Signal processing, xidian univ.rsity, xi'an 710071, china 2. School of Mechanical Engineering, xi'an Jiaotong univ.rsity, xi'an 710049, china) institute of intelligent information processing and Key Laboratory of radar Signal processing Xidian University Xi''an 710071 China School of Mechanical Engineering Xi''an Jiaotong University Xi''an 710049 China

Based on the clonal selection theory and immune memory theory, a novel artificial immune system algorithm, immune memory clonal programming algorithm (IMCpA), is put forward. Using the theorem of Markov chain, it is proved that IMCpA is convergent. Compared with some other evolutionary programming algorithms (like Breeder genetic algorithm), IMCpA is shown to be an evolutionary strategy capable of solving complex machine learning tasks, like high-dimensional function optimization, which maintains the diversity of the population and avoids prematurity to some extent, and has a higher convergence speed.

关键词： clonal selection immune memory artificial immune system evolutionary algorithms Markov chain.

Correlation analysis of target echoes using distributed transmit array

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Science china(information Sciences) 2010年第9期53卷 1860-1868页

作者： JIN Ming*,LIAO GuiSheng & LI Jun National Laboratory of radar Signal processing,xidian univ.rsity,xi’an 710071,china 1. National Laboratory of radar Signal processing Xidian University Xi’an 710071 China

Transmit diversity multiple-input multiple-output(MIMO) radars decorrelate target echoes on distributed transmit array,and then through closely spaced receivers array estimate the angles of multiple targets using the received target echoes without separating transmitted *** this paper,the target echoes correlation is analyzed under Swerling I and Ⅱ target model *** results show that:(1) Target echoes are uncorrelated under Swerling II model;(2) under Swerling I model,in order to decrease the correlation of target echoes by increasing the number of transmitters,it is required that the normalized covariance matrices of the signals before and after the transmitter number increases should satisfy a relation given in this ***,the results are verified by computer simulations of the target echoes correlation and angles estimation performance.

关键词： multiple-input multiple-output(MIMO) radar transmit diversity target echoes decorrelation

Construction of almost optimal resilient Boolean functions via concatenating Maiorana-McFarland functions

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Science china(information Sciences) 2011年第4期54卷 909-912页

作者： ZHANG WeiGuo & xiAO GuoZhen ISN Laboratory,xidian univ.rsity,xi’an 710071,china 1. ISN Laboratory Xidian University Xi’an 710071 China

We describe a method to construct an n-variable (n even) almost optimal resilient Boolean function via concatenating 2 d properly chosen (n-d)-variable Maiorana-McFarland *** an example,a 5-resilient 42-variable Boole... 详细信息

关键词： Boolean functions nonlinearity resiliency stream ciphers

Variable structure multiple model for articulated human motion tracking from monocular video sequences

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Science china(information Sciences) 2012年第5期55卷 1138-1150页

作者： HAN Hong 1,TONG MingLei 2,CHEN ZhiChao 1 & FAN YouJian 1 1 Key Laboratory of intelligent perception and Image Understanding of Ministry of Education of china,institute of intelligent information processing,xidian univ.rsity,xi'an 710071,china 2 School of Computer and information Engineering,Shanghai univ.rsity of Electric power,Shanghai 200090,china 1. Key Laboratory of intelligent perception and Image Understanding of Ministry of Education of china Institute of Intelligent Information Processing Xidian University Xi’an 710071 China2. School of Computer and Information Engineering Shanghai University of Electric Power Shanghai 200090 China

A new model-based human body tracking framework with learning-based theory is introduced in this *** propose a variable structure multiple model (VSMM) framework to address challenging problems such as uncertainty of motion styles,imprecise detection of feature points,and ambiguity of joint *** human joint points are detected automatically and the undetected points are estimated with Kalman *** motion models are learned from motion capture data using a ridge regression *** model set that covers the total motion set is designed on the basis of topological and compatibility relationships,while the VSMM algorithm is used to estimate quaternion vectors of joint *** using real image sequences and simulation videos demonstrate the high efficiency of our proposed human tracking framework.

关键词： human motion tracking ridge regression model groups design variable structure multiple model (VSMM) motion model group adaptation

Timeliness evaluation of task-oriented networked space-based information system

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Journal of Systems Engineering and Electronics 2011年第4期22卷 621-627页

作者： Chen Chen 1,2,and Jie Chen 2,3 1.Department of Automation,Tsinghua univ.rsity,Beijing 100084,p.r.china 2.School of Automation,Beijing institute of Technology,Beijing 100081,p.r.china 3.Complex System intelligent Control and Decision,Ministry of Education,Beijing 100081,p.r.china Department of Automation Tsinghua University Beijing 100084 P. R. China School of Automation Beijing Institute of Technology Beijing 100081 P. R. China School of Automation Beijing Institute of Technology Beijing 100081 P. R. China Complex System intelligent Control and Decision Ministry of Education Beijing 100081 P. R. China

Task-oriented networked information system is an integrated information system which builds on multi-satellite networking to accomplish one or more tasks. In the background of emer- gency relief for applications, system working flow and response process are analyzed, and a timeliness effectiveness evaluation index system is constructed at multi-task level. The effectiveness is a measurement of promptness of information return. In evalua- tion process, system performance and tasks are associated, then an evaluation model based on efficacy function is established, and different evaluation criteria are selected for different tasks. A distributed simulation system is constructed, and the execution of task is decomposed. The simulation platform provides a comprehensive data source for evaluation. The results are easy to compare with each other, which reflects system time efficiency in different satellites networks and provides actual systems with basis and reference for design and application.

关键词： timeliness efficacy function space-based informationsystem simulation system.

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Neuronal population dynamic model: An analytic approach

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progress in Natural Science:Materials International 2009年第9期19卷 1159-1163页

作者： Wentao Huang a, Licheng Jiao a, Yuelei Xub, Shiping Ma b, Jianhua Jia a a institute of intelligent information processing, Key Laboratory of intelligent perception and Image Understanding of Ministry of Education, xidian univ.rsity, p.O. Box 224, xi’an 710071, china b Department of Avionics Engineering, Engineering College of Air Force Engineering univ.rsity, xi’an 710038, china [a]institute of intelligent information processing Key Laboratory of Intelligent Perception and Image Understanding of Ministry of Education Xidian University P.O. Box 224 Xi’an 710071 China [b]Department of Avionics Engineering Engineering College of Air Force Engineering University Xi’an 710038 China

A novel analytic approach is presented to study the population of excitatory and inhibitory spiking neurons in this paper. The evolution in time of the population dynamic equation is determined by a partial differential equation. A new function is proposed to characterize the population of excitatory and inhibitory spiking neurons, which is different from the population density function discussed by most researchers. And a novel evolution equation, which is a nonhomogeneous parabolic type equation, is derived. From this, the stationary solution and the firing rate of the stationary states are given. Last, by the Fourier transform, the time dependent solution is also obtained. This method can be used to analyze the various dynamic behaviors of neuronal populations.

关键词： Analytic approach Neuronal population Dynamic model Fourier transform