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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 university,xi'an 710049,China 2 State Key Lab for Integrated Services Networks,xidian university,xi'an 710071,China 3 Ministry of Education Key Lab for Intelligent Networks and Network Security,xi'an Jiaotong university,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

A new kind of superimposing morphology for enhancing the light scattering in thin film silicon solar cells： Combining random and periodic structure

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Chinese Physics B 2014年第8期23卷 350-356页

作者： Huang Zhen-Hua Institute of Photo-electronics Thin Film Devices and Technique of Nankai university Tianjin 300071 China Key Laboratory of Photo-electronics Thin Film Devices and Technique of Tianjin Tianjin 300071 China Key Laboratory of Photo-electronic Information science and technology of Ministry of Education (Nankai university) Tianjin 300071 China

In this article, a new type of superimposing morphology comprised of a periodic nanostructure and a random structure is proposed for the first time to enhance the light scattering in silicon-based thin film solar cells. According to the framework of the Reyleigh-Sommerfeld diffraction algorithm and the experimental results of random morphologies, we analyze the light-scattering properties of four superimposing morphologies and compare them with the individual morphologies in detail. The results indicate that the superimposing morphology can offer a better light trapping capacity, owing to the coexistence of the random scattering mechanism and the periodic scattering mechanism. Its scattering property will be dominated by the individual nanostructures whose geometrical features play the leading role.

关键词： light scattering superimposing morphology random periodic

A NEW DIGITAL MODULATION RECOGNITION METHOD USING FEATURES EXTRACTED FROM GAR MODEL PARAMETERS

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Journal of Electronics(China) 1999年第3期16卷 244-250页

作者： Lu Mingquan xiao xianci Li Lemin (university of Electronic science and technology of China, Chengdu 610054)

Based on the features extracted from generalized autoregressive (GAR) model parameters of the received waveform, and the use of multilayer perceptron(MLP) neural network classifier, a new digital modulation recognition method is proposed in this paper. Because of the better noise suppression ability of the GAR model and the powerful pattern classification capacity of the MLP neural network classifier, the new method can significantly improve the recognition performance in lower SNR with better robustness. To assess the performance of the new method, computer simulations are also performed.

关键词： Modulation recognition GAR model Feature extraction Neural network classifier

MAPPS: A Framework of Peer-to-Peer Systems Based on JXTA and Mobile Agents

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计算机工程 2002年第S1期28卷 129-132页

作者： LI Yun1,LI Weihua2(Department of Computer science and Engineering, Northwestern Polytechnical university, xi’an 710072, China, ly@*** liweihua@***) Department of Computer science and Engineering Northwestern Polytechnical University Xi'an 710072 China lyhenu.edu. Cn liweihua@nwpu. Edu. Cn

Due to the success of Napster, Gnutella and Freenet, peer to peer (P2P) computing has suddenly emerged at the forefront of Internet computing. And a lot of problems including security, reliability and routing are urgent to be solved. Unfortunately, traditional techniques are not directly applicable to P2P systems. This paper presents a new framework called MAPPS for designing P2P applications based on JXTA and mobile agents. The MAPPS framework is structured as three layers: the MAPPS infrastructure based on mobile agents, MAPPS services and MAPPS applications. In this way, MAPPS not only follows the outstanding architecture of JXTA, but also enhances the mobility and flexibility of P2P systems. Using MAPPS, developers of new P2P systems can design and implement P2P systems more efficiently.

关键词： Peer-to-peer computing JXTA Mobile agent

Analysis on cohesive crack opening displacement considering the strain softening effect

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science China(Physics,Mechanics & Astronomy) 2006年第1期49卷 88-101页

作者： WANG Limin1, XU Shilang2 & ZHAO xiqiang3 1. Mechanics Department, Shandong university of technology, Zibo 255049, China 2. Civil Engineering Department, Dalian university of technology, Dalian 116024, China 3. Mathematics Department, Ocean university of China, Qingdao 266071, China Mechanics Department Shandong University of Technology Zibo 255049 China Civil Engineering Department Dalian University of Technology Dalian 116024 China Mathematics Department Ocean University of China Qingdao 266071 China

In order to investigate the crack propagation in quasi-brittle materials like rock, ceramic and concrete, Hillerborg and his co-researchers abstracted the fracture process zone in front of a stress free crack in terms of a “fictitious crack zone”. On the fictitious crack zone, cohesive stresses distribute following a given softening relationship of stress vs. crack opening. Based on the polynomial or power series expression of cohesive crack opening displacement, the relationship of the cohesive stress vs. the crack opening displacement is established using elastic theory and integral equation, and some unknown physics variables are obtained using variation approach. The calculation results gained in this paper are close to the experimentally test ones.

关键词： cohesive crack, softening, dissipation work, variation approach.

Geo-Agents: Design and Implement

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Wuhan university Journal of Natural sciences 2001年第Z1期6卷 451-459页

作者： Ding Li, Qu Lei, Zhang Ying, Luo Ying wei, Wang xiao lin, Xu Zhuo qun Department of Computer science & technology,Peking university, Beijing 100871, China Department of Computer science & technology Peking University Beijing 100871 China

Geo Agents, a multi agent system that processes distributed geospatial information and geospatial service was presented. Firstly, the requirement for distributed geographical information process was discussed, and the architecture of Geo Agents was introduced. Then in depth discussions were raised on agent system implementation, such as the basic agent, agent advertising, message passing, and collaborating. An example was also given to explain the problem solving process.

关键词： geographical information system (GIS) multi agent system (MAS) Geo Ggents communication collaboration

The Base Distribution Patterns of Protein Coding Sequences, Noncoding ORFs, and Intergenic Sequences in Pseudomonas aeruginosa PA01Genome and Its Implication

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The Base Distribution Patterns of Protein Coding Sequences, ...

PLASMA-FILLED DIELECTRIC CHERENKOV MASER WITH A LONGITUDINAL MAGNETIC FIELD

中国遗传学会功能基因组学研讨会

作者： Feng-Biao Guo School of Life science and technology, university of Electronic science and technology of China, Chengdu, 610054,China

The base distribution patterns of DNA fragments in different regions in P. aeruginosa genome are analyzed in this paper. It’s astonishingly shown that 5565 protein coding sequences, 17315 noncoding ORFs and 1104 intergenic sequences can be divided into several clusters according to their base distribution patterns. And almost all the protein coding sequences are contained in one cluster of them. The significantly different base frequencies at three codon positions, which

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Journal of Electronics(China) 1996年第3期13卷 249-256页

作者： Wu Jianqiang Song Liqun Liu Shenggang (university of Electronic science and technology of China, Chengdu 610054)

The use of a background plasma in a dielectric Cherenkov maser can effectively increase the efficiency and the microwave output power of the device. Here, the effect of the longitudinal uniform magnetic field on the wave-beam interaction of the plasma-filled dielectric Cherenkov maser is examined by solving the beam-plasma, dielectric lined waveguide dispersion equation. And the effects of the longitudinal magnetic field, plasma density and dielectric parameters on the linear spatial growth rate and the energy ratio are presented.

关键词： Longitudinal magnetic field Plasma Dielectric Cherenkov maser

Progress in Robustness Designs for Cellular Neural Network

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Progress in Robustness Designs for Cellular Neural Network