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Robust cooperative spectrum sensing schemes for fading channels in cognitive radio networks

science china(Information sciences) 2011年第2期54卷 348-359页

作者： YUE WenJing1,2. ZHENG BaoYu1,2. MENG QingMin1, CUI JingWu1 & XIE PeiZhong1 1Institute of Signal Processing and Transmission, nanjing University of posts and {2., nanjing 2.0003, china 2.epartment of electronic engineering, Shanghai Jiaotong University, Shanghai 2.02.0, china 1. Institute of Signal Processing and Transmission Nanjing University of Posts and Telecommunications Nanjing 210003 China2. Department of Electronic Engineering Shanghai Jiaotong University Shanghai 200240 China

In cognitive radio systems, cooperative spectrum sensing can detect the presence of the primary user accurately. In practice, however, since the sensing observations are forwarded to a data collector through fading channels, the sensing performance is severely degraded. To deal with this problem, in this paper, we first propose a secondary user selection based cooperative spectrum sensing method to improve sensing performance by decreasing the reporting errors introduced by the fading channels. More specifically, only the secondary users with better signal-to-noise ratio (SNR) for reporting channels are allowed to send their local binary decisions (0 or 1) to the data collector while the others will send nothing. Additionally, we further propose a diversity based cooperative spectrum sensing method which applies existing space-time coding. By exploiting space diversity in CR network, the reporting errors introduced by the fading channel can be decreased and then the sensing performance is improved significantly. For either proposed cooperative spectrum sensing method, the sensing performance is derived and the analytical performance results are given. Our analysis and numerical results verify that proposed methods outperform the conventional cooperative spectrum sensing with OR-rule by taking into account the error effect on the reporting channels.

关键词： cognitive radio (CR) spectrum sensing energy detection diversity technique space-time coding

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Study on An Absolute Non-Collision Hash and Jumping Table IP Classification Algorithms

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Wuhan University Journal of Natural sciences 2004年第5期9卷 835-838页

作者： SHANG Feng-jun 1,2.,PAN Ying-jun 1 1. Key Laboratory of Opto-electronic Technology and System of Ministry of Education/college of Opto-electronic engineering,Chongqing University, Chongqing 400044,china 2. college of Computer science and Technology, Chongqing University of posts and telecommunications, Chongqing 400065,china Chongqing University Key Laboratory of Opto-Electronic Technology and System of Ministry of Education/College of Opto-Electronic Engineering Chongqing China (GRID:grid.190737.b) (ISNI:***) Chongqing University of posts and telecommunications College of Computer Science and Technology Chongqing China (GRID:grid.411587.e) (ISNI:***) Chongqing University Key Laboratory of Opto-Electronic Technology and System of Ministry of Education/College of Opto-Electronic Engineering Chongqing China (GRID:grid.190737.b) (ISNI:***)

In order to classify packet, we propose a novel IP classification based the non-collision hash and jumping table trie-tree (NHJTTT) algorithm, which is based on noncollision hash Trie-tree and Lakshman and Stiliadis proposing a 2.dimensional classification algorithm (LS algorithm). The core of algorithm consists of two parts: structure the non-collision hash function, which is constructed mainly based on destination/source port and protocol type field so that the hash function can avoid space explosion problem; introduce jumping table Trie-tree based LS algorithm in order to reduce time complexity. The test results show that the classification rate of NHJTTT algorithm is up to 1 million packets per second and the maximum memory consumed is 9 MB for 10 000 rules. Key words IP classification - lookup algorithm - trie-tree - non-collision hash - jumping table CLC number TN 393.06 Foundation item: Supported by the Chongqing of posts and telecommunications Younger Teacher Fundation (A2.03-03).Biography: SHANG Feng-jun (1972.), male, Ph.D. candidate, lecture, research direction: the smart instrument and network.

关键词： IP classification lookup algorithm trie-tree non-collision hash jumping table

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Low-complexity distributed differential spacetime coding scheme for amplify-and-forward cooperative networks

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science in china(Series F) 2009年第8期52卷 1418-1427页

作者： YU XiangBin1,2. BI GuangGuo3 & XU WeiYe4 1 college of Information science and Technology, {2. University of Aeronautics and Astronautics, {2. 2.0016, china 2.Department of electronic engineering, City University of Hong Kong, Hong Kong, china 3 National Mobile Communications Research Laboratory, Southeast University, {2. 2.0096, china 4 Department of Communication engineering, {2. Institute of Technology, {2. 2.1167, china college of Information science and Technology Nanjing University of Aeronautics and Astronautics Nanjing 210016 China Department of electronic engineering City University of Hong Kong Hong Kong China National Mobile Communications Research Laboratory Southeast University Nanjing 210096 China Department of Communication engineering Nanjing Institute of Technology Nanjing 211167 China

By introducing a space-time coding scheme based on amicable orthogonality, we develop a distributed differential space-time coding scheme with the amplify-and-forward （AF） method for wireless cooperative networks. The scheme requires no knowledge of the channel state information at both transmitters and receivers, and effectively decreases the realization complexity due to no channel estimation. Moreover, it has lower decoding complexity and higher coding advantage than the existing scheme, thus avoiding the shortcoming of exponential decoding complexity of some existing schemes. According to the pairwise error probability （PEP） analysis of the system, the power allocations of source and relay terminals are jointly optimized, and as a result, the PEP is minimized, which will provide a helpful guideline for system design. Numerical calculation and simulation results show that the developed scheme is superior to the existing scheme. Moreover, the scheme with optimal power allocation yields obvious performance improvement over that with equal power allocation.

关键词： differential space-time coding cooperative communication amplify-and-forward method power allocation

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A new policy to solve routing conflicts in shuffle-exchange networks

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science china(Information sciences) 2011年第7期54卷 1512-1523页

作者： GE FangBin 1,ZHAO Min 1,ZHANG Tao 1 & WANG JianXin 2.1 college of Command Automation PLA University of science and Technology,{2. 2.0007,china 2.Institute of china electronic System engineering,Beijing 100039,china 1. college of Command Automation PLA University of science and Technology Nanjing 210007 China2. Institute of China Electronic System Engineering Beijing 100039 China

Batch routing is an important approach for solving routing conflicts in SE (shuffle-exchange) ***,the complexity of batching and the uncertainty of batch size makes this approach *** on sequence division and routing coding concepts,we propose a method for detecting routing conflicts in an SE network,known as dividing detection that is more efficient than the method for window *** addition,a new conjecture relating to routing policies in SE networks is *** is proved using a constructive approach when n < *** on the conjecture,a new routing scheme for SE networks is *** this scheme,all the input signals can be transfered without conflicts and within two batches,while the efficiency of the batch routing is noticeably improved.

关键词： shuffle-exchange network sequence division routing coding transition sequence educed sequence

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Theoretical analysis of alloy multiplying factor by the empirical electron theory of solids and molecules

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science china(Technological sciences) 2007年第6期50卷 807-814页

作者： SONG YuePeng1,2. LIU GuoQuan2. LI ZhiLin3, FENG ChengMing1 1 Mechanical and electronic engineering {2., Shandong Agricultural University, Tai’an 2.1018, china 2.college of Materials science and engineering, University of science and Technology, Beijing 100083, china 3 {2. of Material science and engineering, Beijing University of Chemical Technology, Beijing 10002., china Mechanical electronic engineering {2. Shandong Agricultural University Tai’an 271018 China college of Materials science engineering University of Science Technology Beijing 100083 China college of Material science engineering Beijing University of Chemical Technology Beijing 100029 China

By introducing the distribution probability of structural units in austenite contain- ing alloying elements and considering its effects on phase transformation, this paper establishes a calculation model of distribution probability of structural units. A new valence electron structure (VES) parameter-transformation effect coefficient of alloying elements (HL), is defined and then studied both theoretically and ex- perimentally. The relationship between the parameter HL and the multiplying factor (the quenching capability factor) of alloying elements is studied. The results indi- cate that the two parameters (HL and the quenching capability factor) have the same variation characteristic and substance feature. Therefore, the multiplying factor virtually expresses the relative quantity of structural units in the alloying elements-containing austenite.

关键词： multiplying factor (the quenching capability factor), empirical electron theory of solids and molecules, transformation effect coefficient of alloying elements, structural units in austenite containing alloying elements

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Magnetron sputtering synthesis of large area well-ordered boron nanowire arrays

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science china(Physics,Mechanics & Astronomy) 2004年第4期47卷 403-415页

作者： CAO Limin1,2. ZHANG Ze2.& WANG Wenkui1,2.1. Key Laboratory of Metastable Materials science and Technology and college of Materials science and engineering, Yanshan University, Qinhuangdao 066004, china 2. Institute of Physics, Chinese Academy of sciences, Beijing 100080, china 1. Key Laboratory of Metastable Materials science and Technology and college of Materials science and engineering Yanshan University 066004 Qinhuangdao China 2. Institute of Physics Chinese Academy of Sciences 100080 Beijing China

One-dimensionally nanostructured materials, such as nanowires and nanotubes, are the smallest dimensional structures for efficient transport of electrons and excitons, and are therefore critical building blocks for nanoscale electronic and mechanical devices. In this paper, boron nanowires with uniform diameters from 2. to 80 nm were synthesized by radio-frequency magnetron sputtering of pure boron powder and B2.3 powder mixtures in argon atmosphere. The boron nanowires produced stand vertically on the substrate surface to form well-ordered arrays over large areas with self- organized arrangements without involvement of any template and patterned catalyst. The high-density boron nanowires are parallel to each other and well distributed, forming highly ordered and uniform arrays. A more interesting and unique feature of the boron nanowires is that most of their tips are flat rather than hemispherical in morphologies. Detailed studies on its structure and composition indicate that boron nanowires are amorphous. Boron nanowire appears as a new member in the family of one-dimensional nanostructures. Considering the unique properties of boron-rich solids and other nanostructures, it is reasonable to expect that the boron nanowires will display some exceptional and interesting properties. A vapor-cluster-solid (VCS) mechanism was proposed to explain the growth of boron nanowires based on our experimental observations.

关键词： boron nanowires, magnetron sputtering, arrays, self-assembly.

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Signal Blind Recover in Communication Systems using Support Vector Machines

Signal Blind Recover in Communication Systems using Support ...

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2.08年中国高校通信类院系学术研讨会

作者： Yin Li-he~1 Ruan Xiu-kai~2.1 college of electronic {2. and engineering,nanjing University of posts & telecommunications,nanjing,2.0003 2.college of telecommunications & Information engineering,nanjing University of posts & telecommunications,nanjing,2.0003

＜正＞This paper focuses on the applications of the support vector machine in solving the problem of blind recover in digital communication *** introduce the technique of support vector machine briefly,the development of blind equalization and analyze the problems which need to be resolved of the blind *** the applicability of support vector machine in blind problem is highlighted and ***,merit and shortage of blind equalization using support vector machine which is already exist to be discussed and the direction of further research is indicated.

关键词： Blind Equalization Support Vector Machines Lagrange Convex Quadratic programming BPSK

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Kinetics analysis of volume phase transition of intelligent neutral thermo-sensitive hydrogels

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science china(Physics,Mechanics & Astronomy) 2008年第5期51卷 532-540页

作者： WANG XiaoGui1 & LI YiQuan2.1 college of Mechanical engineering,Zhejiang University of Technology,Hangzhou 310032.{2. 2.School of Mechanical & electronic engineering,Changchun University of science and Technology,Changchun 13002.,{2. 1. college of Mechanical engineering Zhejiang University of Technology Hangzhou 310032 China 2. School of Mechanical & electronic engineering Changchun University of Science and Technology Changchun 130022 China

In this work,utilizing the first law of thermodynamics and the Flory mean-field theory,the kinetic deformation studies concerning the volume phase transition of the neutral thermo-sensitive hydrogels were performed *** hydrogel was assumed as a biphasic mixture medium in the framework of the continuum mixture *** the energy conservation of the thermodynamics system of the hydrogel,the governing equations for the kinetics of the nonlinear large deforma-tion were *** explicit analytical expressions of the effective stress tensor and the chemical potential of the fluid of the thermo-sensitive hydrogel PNIPA were also obtained from the Helmholtz free energy,which can model the steady-static volume phase transition quantitatively.

关键词： thermo-sensitive hydrogel volume phase transition effective stress energy conservation

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Improving the secrecy rate by turning foes to allies:An auction scheme

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Chinese Physics B 2015年第9期24卷 80-90页

作者：马亚燕王保云 college of Communication and Information engineering Nanjing University of Posts and Telecommunications

Security against eavesdroppers is a critical issue in cognitive radio networks（CRNs）. In this paper, a scenario consisting of one primary pair and multiple secondary pairs is considered. The secondary transmitters（STs） work in half-duplex mode and they are potential eavesdroppers on the primary transmission unless they are allowed to simultaneously transmit with the primary transmitter（PT）. A modified second-price sealed-bid auction scheme is employed to model the interaction between the PT and STs. With the proposed auction scheme, the hostile relationship between the PT and STs is transformed into a cooperative relationship. An iterative algorithm based on the max–min criteria is proposed to find the optimal bidding power of the STs for an access chance in the presence of multiple eavesdroppers. Numerical results show that the proposed auction scheme not only improves the PT＇s security but also increases the access opportunities of the STs.

关键词： security auction cooperation cognitive radio networks

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Electrophoretic Coating of Hydroxyapatite on Pyrolytic Carbon Using Glycol as Dispersion Medium

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Journal of Wuhan University of Technology(Materials science) 2008年第3期23卷 293-297页

作者：高林 college of Life science and Technology Huazhong University of Science and Technology college of Chemistry and Environmental engineering Yangtze UniversityJingzhou 434023China

Hydroxyapatite （HA） coatings on pyrolytic carbon were produced via electrophoretic deposition （EPD） using glycol and ethanol as dispersion medium respectively. The effect of the solubility of HA in the dispersion medium on crack occurrence and adherence of the coating was investigated by means of scanning electronic microscope （SEM） and atomic absorption spectrometer （AAS）. The results show that the solubility of HA in glycol is higher than that in ethanol. The usage of glycol as a dispersion medium can reduce the possibility of crack formation and enhance the adhesive strength between the coating and the carbon substrate. The green coatings can be sintered under vacuum at 1 000 ℃ whether the coatings are obtained using ethanol or glycol as dispersion medium. No HA decomposition was observed up to 1 000 ℃ by vacuum sintering by X-ray diffraction （XRD） analysis.

关键词： hydroxyapatite electrophoretic deposition coatings dispersion medium glycol

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