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A novel radio resource allocation scheme for IEEE 802.16e multicell networks

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Science china(information Sciences) 2011年第7期54卷 1444-1455页

作者： LIU Jian ,LONG KePing & XU Jie School of communication and information engineering,university of Electronic Science and technology,chengdu 611731,china School of communication and information engineering University of Electronic Science and Technology Chengdu China

In this paper,we propose a new media access control (MAC) protocol,which is compatible with the IEEE 802.16e-2005 Orthogonal Frequency Division Multiple Access (OFDMA) wireless *** this protocol,the same radio resource can be shared by neighboring cells in the wireless mesh network (WMN) and collisions can be reduced in the overlapping *** protocol consists of two schemes: a downlink transmission and an uplink *** downlink transmission we use a cross layer adaptive radio resource allocation (CL-ARRA) scheme,which consists of two steps: a dynamic subcarrier allocation (DSA) and a dynamic power allocation (DPA).For uplink transmission we propose a new subcarrier backoff scheme and use the Markov chain model to analyze this *** this protocol,we analyze the performance of the downlink and the uplink operation in the OFDMA *** analytical results are well matched to the simulation *** then extend our model to a star-mesh topology with multiple overlapped *** results show that the performance can be improved with the application of the superior capability of our proposed MAC protocol to deal with collisions in the overlapped regions.

关键词： orthogonal frequency division multiple access (OFDMA) 802.16e overlapping area wireless mesh network (WMN) cross layer design dynamic subcarrier allocation (DSA) dynamic power allocation (DPA) Markov chain

Photonic band gap from periodic structures containing anisotropic nonmagnetic left-handed metamaterial

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Chinese Optics Letters 2010年第4期8卷 431-434页

作者：唐婷婷陈福深孙豹 Key Laboratory of Broadband Optical Fiber Transmission and communication Networks in university of Electronic Science and technology of china Ministry of Education department of Optoelectronic technology Chengdu University of Information Technology Key Laboratory of Broadband Optical Fiber Transmission and communication Networks in university of Electronic Science and technology of china Ministry of Education

We demonstrate a photonic band gap（PBG） from one-dimensional（1D） periodic structures created by a double-layer unit cell with an air layer and an anisotropic nonmagnetic left-handed metamaterial（LHM） layer whose permittivity elements are partially *** requirements imposed on the materials and structures to realize a PBG are derived when the frequency is above or below the cutoff frequency,and the transmission properties of the PBG are discussed by utilizing 4×4 transfer-matrix method with dispersive semiconductor metamaterial.

关键词： Anisotropy Cutoff frequency Energy gap Metamaterials Photonic band gap Transfer matrix method

Construction of a multidimensional plane network-on-chip architecture based on the hypercube structure

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Progress in Natural Science:Materials International 2009年第5期19卷 635-641页

作者： Chang Wu, Yubai Li, Qicong Peng, Song Chai, Zhongming Yang DSP Lab, School of communication and information engineering, university of Electronic Science and technology of china, chengdu 610054, china DSP Lab School of Communication and Information Engineering University of Electronic Science and Technology of China Chengdu 610054 China

In current network-on-chip (NOC) studies and in practical applications, the mesh structure is the most widely used and deeply researched structure. However, the hypercube structure is more symmetrical and regular than the mesh or torus structures. This paper compares the network characteristics of these three direct topologies and proposes a method to compress the hypercube into a plane structure. This structure, which has the multidimensional property based on the hypercube, is called the multidimensional plane (MDP) NOC. The compression process is divided into two steps: the transformation of router denotations and the connection of channels. Then, SystemC is used to implement the MDP NOC and it is compared with the mesh and torus NOCs in terms of four aspects of performance, including average latency time, normalization throughput, energy consumption and area cost.

关键词： NOC Hypercube Dimension SystemC Simulation

ON F-z-SUPPLEMENTED SUBGROUPS OF FINITE GROUPS

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Acta Mathematica Scientia 2011年第1期31卷 22-28页

作者：郭文彬唐娜李保军 department of Mathematics University of Science and Technology of China department of Mathematics Xuzhou Normal University department of Mathematics Huaiyin Teachers College School of Mathematics Chengdu University of Information Technology

A subgroup H of a group G is called F-z-supplemented in G if there exists a subgroup K of G, such that G = HK and H∩K≤ Z∞F（G）, where Z∞F（G） is the F-hypercenter of G. We obtain some results about the F-z-suppl... 详细信息

关键词： Finite groups local formations F-z-supplemented subgroups supersoluble groups p-nilpotent groups

Two-dimensional water-filling power allocation algorithm for MIMO-OFDM systems

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Science china(information Sciences) 2010年第6期53卷 1242-1250页

作者： JIANG YongQuan 1 , SHEN MinFen 1 & ZHOU YuanPing 2 1 department of Electronic engineering, Shantou university, Shantou 515063, china 2.department of Electronic engineering, Sichuan university, chengdu 610064, china department of Electronic engineering Shantou University Shantou China department of Electronic engineering Sichuan University Chengdu China

Departing from the narrowband channel model, more and more researchers have recently considered the application of multiple-input multiple-output(MIMO) systems over frequency-selective fading channels in combination with the orthogonal frequency-division multiplexing(OFDM) *** this paper, we focus on the capacity of MIMO-OFDM systems and how to increase the *** has been proved that the capacity of a MIMO system with space-dimensional water-filling power allocation is greater than that of the system with uniform power *** MIMO-OFDM systems, there is an additional degree of freedom to allocate power with respect to MIMO systems:the OFDM sub-channels in *** the singular value decomposition(SVD) applied to the channel frequency response matrix, the two-dimensional water-filling power allocation algorithm for MIMO-OFDM systems is proposed based on the Lagrange method, and the corresponding capacity analysis formula is *** results show that the capacity of a MIMO-OFDM system with the proposed two-dimensional water-filling power allocation is greater than that of the system with uniform power allocation and also greater than that of the system with the one-dimensional water-filling power allocation.

关键词： MIMO-OFDM two-dimensional water-filling power allocation capacity analysis singular value decomposition(SVD)

Bell violation for the thermal states of an XXZ spin chain with Dzialoshiski-Moriya interaction

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Science china(Physics,Mechanics & Astronomy) 2010年第11期53卷 2074-2079页

作者： MA XiaoSan 1 & WANG AnMin 2 1 School of Electric engineering and information,Anhui university of technology,Maanshan 243002,china 2.department of Modern Physics,university of Science and technology of china,Hefei 230026,china School of Electric engineering and information Anhui University of Technology Maanshan China department of Modern Physics University of Science and Technology of China Hefei China

The effect of Dzialoshiski-Moriya (DM) interaction on the violation of Bell inequality for thermal states of interacting qubits via a two-qubit XXZ spin chain is *** results imply that the DM interaction and anisotropy taking a large positive value can enhance the Bell violation and improve the threshold temperatures of *** the comparison between the Bell violation and thermal entanglement,we find that the threshold temperatures of thermal entanglement are higher than those of the Bell *** implies that some states are entangled but the Bell inequality is not violated.

关键词： Bell violation threshold temperatures DM interaction

Frequency/time hopping sequence sets with optimal partial Hamming correlation properties

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Science china(information Sciences) 2012年第10期55卷 2207-2215页

作者： NIU XianHua 1,2,PENG DaiYuan 1 & ZHOU ZhengChun 3 1 The Provincial Key Laboratory of information Coding and Transmission,Institute of Mobile communications,Southwest Jiaotong university,chengdu 610031,china 2 The School of Mathematics and Computer engineering,Xihua university,chengdu 610039,china 3 The College of Maths,Southwest Jiaotong university,chengdu 610031,china The Provincial Key Laboratory of information Coding and Transmission Institute of Mobile Communications Southwest Jiaotong University Chengdu China The School of Mathematics and Computer engineering Xihua University Chengdu China The College of Maths Southwest Jiaotong University Chengdu China

Frequency hopping/time hopping(FH/TH) sequences have found wide applications in various modern FH/TH spread spectrum communications,such as digital cellular mobile communication,short-range wireless communication,personal communication,and multi-user radar,sonar *** order to evaluate the goodness of FH/TH sequences design,the periodic Hamming correlation function is used as an important ***,the length of correlation window is shorter than the period of the chosen FH/TH sequence,so the study of the partial Hamming correlation of FH/TH sequence is particularly *** this paper,a new class of FH/TH sequence sets with good partial Hamming correlation properties is proposed and *** construction of new FH/TH sequence sets is based upon the generalized m-sequence and generalized Gordon-Mills-Welch sequence over a polynomial residue class *** is shown that new FH/TH sequence sets are optimal with respect to the partial Hamming correlation bound.

关键词： frequency hopping/time hopping(FH/TH) sequence partial Hamming correlation optimal FH/TH sequence set

Image space analysis for variational inequalities with cone constraints and applications to traffic equilibria

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Science china Mathematics 2012年第4期55卷 851-868页

作者： LI Jun 1,& HUANG NanJing 2 1 College of Mathematics and information,china West Normal university,Nanchong 637009,china 2.department of Mathematics,Sichuan university,chengdu 610064,china College of Mathematics and information China West Normal University Nanchong China department of Mathematics Sichuan University Chengdu China

In this paper,the image space analysis (for short,ISA) is employed to investigate variational in- equalities (for short,VI) with cone *** separation for VI with cone constraints is characterized by using the normal cone to a regularization of the image,and saddle points of the generalized Lagrangian func- ***-type necessary and sufficient optimality conditions for VI with cone constraints are presented by using a separation *** functions and weak sharpness for VI with cone constraints are also investi- ***,the obtained results are applied to standard and time-dependent traffic equilibria introduced by Daniele,Maugeri and Oettli.

关键词： variational inequality image space analysis linear separation necessary and sufficient optimalitycondition traffic equilibrium

Land Use of the Three Gorges Reservoir Area and the Effect on Its Landscape Pattern in the Recent 50 Years

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Wuhan university Journal of Natural Sciences 2006年第4期11卷 910-914页

作者： HUANG Zhiqin 1,2,3 , ZHOU Wancun 1 ,ZHOU Jieming 4 , ZHU Mingcang 3,5 1. Institute of Mountain Hazards and Environment, Chinese Academy of Sciences , chengdu 610041, Sichuan, china 2. Graduate university of Chinese Academy of Sciences, Beijing 100049, china 3. Sichuan Institute of Land Resource Management, chengdu 610041, Sichuan , china 4. department of Resources and Environment Science, Sichuan Normal university , chengdu 610061, Sichuan, china 5. College of information engineering, chengdu university of technology, chengdu 610059, Sichuan, china Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu Sichuan China Graduate university of Chinese Academy of Sciences Beijing China Sichuan Institute of Land Resource Management Chengdu Sichuan China department of Resources and Environment Science Sichuan Normal University Chengdu Sichuan China College of information engineering Chengdu University of Technology Chengdu Sichuan China

The paper makes detailed analysis on the changing processes of the main types of land use in Three Gorges Reservoir Area through the techniques of RS （Remote Sense） and GIS （Geography information System）. Based on the theory of landscape ecology, many types of landscape pattern indexes are calculated and made correlation analysis. The results indicate that： in 1995 the ecological environment of Three Gorges Reservoir Area was the most vulnerable in the recent 50 years, but resumed in 2002; the landscape pattern diversity index, fractal dimension index and fragmentation index has close correlation with the area of land use/cover change （LUCC）. The research also releases that the increase of the cultivated land, grassland and construction land deteriorates the landscape ecological pattern, while the increase of forest land area will help restore the landscape ecological pattern to its original state. The rapid change of grassland is an important index of the change of landscape pattern, because it has the most effect on change of landscape pattern index.

关键词： the Three Gorges Reservoir Area land use/cover change landscape pattern.