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Synchronization of MIMO OFDM systems by perfect complete generalized complementary orthogonal loosely synchronous code groups

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The Journal of china.Universities of posts and Telecommunications 2009年第2期16卷 1-7页

作者： wang Jian YANG Xun LI Dao-ben school of Information Engineering,beijing {3. of posts and Telecommunications,beijing 100876,china [a]school of Information Engineering beijing university of posts and Telecommunications beijing 100876 china

This article proposes a time/frequency synchronization algorithm in the multiple input multiple output （MIMO） systems, in which the perfect complete generalized complementary orthogonal loosely synchronous code groups are used as the synchronization sequence. The synchronization algorithm is divided into four stages： 1） synchronization in time domain by signal autocorrelation; 2） synchronization in frequency domain by fast Fourier transform （FFT）; 3. multipath dissociation using coherent detection and fine time synchronization; 4） fine frequency offset estimation by phase rotation. As per the perfect complete generalized complementary orthogonal loosely synchronous code groups, the cross-correlation and out-of-phase auto-correlation for any relative shift between any two codes is always zero. This ideal property makes the time/frequency synchronization algorithm simple and efficient. The simulation results show that even in the multipath fast fading channel with low signal noise ratio （SNR）, the MIMO system can get synchronized both in the time domain and frequency domain with high stability and reliability.

关键词： MIMO OFDM synchronization complementary orthogonal code loosely synchronous (LS) code

Generalized quantum state sharing of the arbitrary two particles state

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science china.Physics,Mechanics & Astronomy) 2010年第11期53卷 2064-2068页

作者： wang Chuan 1,2,ZHANG Yong 1,2 & JIN GuangSheng 1,2 1 school of science,{3. university of posts and Telecommunications,beijing 100876,china.2 Key Laboratory of Optical Communication and Lightwave Technologies,{3. university of posts and Telecommunications,beijing 100876,china 1. school of science Beijing University of Posts and Telecommunications Beijing 100876 China2. Key Laboratory of Optical Communication and Lightwave Technologies Beijing University of Posts and Telecommunications Beijing 100876 China

This paper has proposed a generalized quantum state sharing protocol of an arbitrary two-particle state using non-maximally GHZ states and generalized Bell state *** sender Alice performs two-particle generalized Bell state measurements on her two particles in the state sharing process and the controller takes measurements on his particles and transfers the quantum information to the receiver with entanglement swapping by the cooperation of the other *** is found that the use of nonmaximally entangled state in quantum state sharing has enabled the secure sharing of the quantum state.

关键词： quantum state sharing quantum entanglement arbitrary two particles state

Error exponents for two-hop Gaussian multiple source-destination relay channels

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science china.Information sciences) 2012年第2期55卷 348-359页

作者： DENG PanLiang1,3.LIU YuanAn1,3.XIE Gang2,3.wang XiaoYu1,3.TANG BiHua1,3.& SUN JianFeng1,3.1school of Electronic Engineering,beijing {3. of posts and Telecommunications,beijing 100876,china.2school of Information and Communication Engineering,beijing {3. of posts and Telecommunications,beijing 100876,china.3.ey Laboratory of Universal Wireless Communication,Ministry of Education,beijing 100876,china 1. school of Electronic Engineering Beijing University of Posts and Telecommunications Beijing 100876 China3. Key Laboratory of Universal Wireless Communication Ministry of Education Beijing 100876 China2. School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing 100876 China

We investigate the two-hop multiple source-destination relay channels using the rate splitting trans-mission scheme where each source can split its message into private and public *** determine the system error probability via integrated exponent function under amplify-and-forward(AF)and decode-and-forward(DF)relay *** most significant difference between AF and DF system error probability evaluations lies in a minimized cut-set bound of transmission rate under the DF *** are many cases among transmission rate intervals for different system parameters(*** power)and it is extremely complex to derive the system error probability for the DF *** obtain a relatively simple result,which unifies various cases by a few *** results show that the system error probability decreases with the increase of the public ***,in order to draw deep insight into the reliability requirement of each source node in this network,we provide the error exponent region(EER)for different source nodes to show the trade-off of error probability among source nodes.

关键词： error exponent error exponent region rate splitting multiple source-destination relay channel

Microstructure and Hot Tearing Sensitivity Simulation and Parameters Optimization for the Centrifugal Casting of Al-Cu Alloy

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Computers, Materials & Continua 2024年第8期80卷 2873-2895页

作者： xueli He Shengkun Lv Ruifeng Dou Yanying Zhang Junsheng wang Xunliang Liu Zhi Wen school of Energy and Environmental Engineering(SEEE) University of Science and Technology Beijing(USTB)Beijing100083China Advanced Research Institute of Multidisciplinary science(ARIM) Beijing Institute of Technology(BIT)Beijing100081China

Four typical theories on the formation of thermal tears:strength,liquid film,intergranular bridging,and solidifica-tion shrinkage compensation *** these theories,a number of criteria have been derived for predicting the formation of thermal cracks,such as the stress-based Niyama,Clyne,and RDG(Rapaz-Dreiser-Grimaud)*** this paper,a mathematical model of horizontal centrifugal casting was established,and numerical simulation analysis was conducted for the centrifugal casting process of cylindrical Al-Cu alloy castings to investigate the effect of the centrifugal casting process conditions on the microstructure and hot tearing sensitivity of alloy castings by using the modified RDG hot tearing *** show that increasing the centrifugal rotation and pouring speeds can refine the microstructure of the alloy but increasing the pouring and mold preheating temperatures can lead to an increase in grain *** grain size gradually transitions from fine grain on the outer layer to coarse grain on the inner ***,combined with the modified RDG hot tearing criterion,the overall distribution of the castings’hot tearing sensitivity was *** analysis results indicate that the porosity in the middle region of the casting was large,and hot tearing defects were prone to *** hot tearing tendency on the inner side of the casting was greater than that on the outer *** effects of centrifugal rotation speed,pouring temperature,and preheating temperature on the thermal sensitivity of Al-Cu alloy castings are summarized in this *** study revealed that the tendency of alloy hot cracking decreases with the increase of the centrifugal speed,and the maximum porosity of castings decreases first and then increases with the pouring *** the preheating temperature increases,the overall maximum porosity of castings shows a decreasing trend.

关键词： Centrifugal casting Al-Cu alloy microstructure hot tearing simulation

The band structures of BSb and B_xGa_(1-x)Sb alloys

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science china.Physics,Mechanics & Astronomy) 2009年第6期52卷 843-847页

作者： XIONG DePing1, ZHOU ShouLi2, wang Qi3. LUO Li1, HUANG YongQing3.& REN XiaoMin3.1 school of Physics and Optoelectronic Engineering, Guangdong university of Technology, Guangzhou 510006, {3.2 College of Information Engineering, Zhejiang university of Technology, Hangzhou 3.003., {3.3.Key Laboratory of Optical Communication and Lightwave Technologies Ministry of Education, beijing university of posts and Telecommunications, beijing 100876, china 1. school of Physics and Optoelectronic Engineering Guangdong University of Technology Guangzhou 510006 China 2. College of Information Engineering Zhejiang University of Technology Hangzhou 310032 China 3. Key Laboratory of Optical Communication and Lightwave Technologies Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China

The band structures of BSb and BxGa1-xSb alloys are studied using first-principles calculations in the generalized gradient approximation. By SQS-8 supercells to model a random alloy, the direct transition energy-gap (Γ15v- Γ1c) bowing of 3.0 eV is obtained for BxGa1-xSb alloys in x = 0-50%, in x = 0-11% the energy-gap is the band-gap and increases by 7 meV/%B with boron composition increasing; by SQS-16 supercells the bowing parameter is about 1.9 eV in x = 0-12.5%. The formation enthalpies of mixing, ΔH, are calculated for BxGa1-xAs and BxGa1-xSb alloys. A comparison of enthalpies indicates that BxGa1-xSb films with boron composition of 7% may be possible.

关键词： band-gap bowing parameter boride alloys

Power functions with low uniformity on odd characteristic finite fields

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science china.Mathematics 2010年第8期53卷 1931-1940页

作者： ZHA ZhengBang 1,3.& wang xueli 2 1 school of Mathematical {3.s,Luoyang Normal university,Luoyang 471022,china.2 school of Mathematical {3.s,South china.Normal university,Guangzhou 51063.,china.3.State Key Laboratory of Information Security,Graduate university of Chinese Academy of {3.s,{13. 100049,china 1. school of Mathematical sciences Luoyang Normal University Luoyang 471022 China3. State Key Laboratory of Information Security Graduate University of Chinese Academy of Sciences Beijing 100049 China2. School of Mathematical Sciences South China Normal University Guangzhou 510631 China

In this paper,we give some new low differential uniformity of some power functions defined on finite fields with odd *** corollaries of the uniformity,we obtain two families of almost perfect nonlinear functions in GF... 详细信息

关键词： almost perfect nonlinear function differential uniform function finite field

Investing and Pricing with Supply Uncertainty in Electricity Market:A General View Combining Wholesale and Retail Market

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china.Communications 2015年第3期12卷 20-34页

作者： LI Xiaobo GAO Li wang Gongpu GAO Feifei WU Qingwei beijing university of posts and Telecommunications school of Digital Media and Design Arts Beijing University of Posts and Telecommunications school of Computer and Information Technology Beijing Jiaotong University Department of Automation Tsinghua UniversityState Key Lab of Intelligent Technologies and SystemsTsinghua National Laboratory for Information Science and Technology(TNList)

Renewable energy,such as wind and solar energy,may vary signifi cantly over time and locations depending on the weather and the climate *** leads to the supply uncertainty in the electricity(power) market with renewable energy integrated to power *** this paper,electricity in the market is classified into two types:stablesupply electricity(SSE) and unstablesupply electricity(USE).We investigate the investment and pricing strategies under the electricity supply uncertainty in wholesale and retail electricity *** particular,our model combines the wholesale and retail market and capture the dominant players,i.e.,consumers,power plant(power operator),and electricity *** derive the market behaviors of these players,we formulate the market decision problems as a multistage Stackelberg *** solving the game model,we obtain the optimal,with closedform,wholesale investment and retail pricing strategy for the *** also obtain the energy supplier's best price mechanism numerically under certain *** fi nd the price of SSE being about 1.4 times higher than that of USE will benefi t energy supplieroptimally,under which power plant's optimal strategy of investing is to purchase USE about 4.5 times much more than SSE.

关键词： electricity supply with uncertainty electricity investment electricity pricing wholesale market retail market Stackelberg game

Joint Optimization of Satisfaction Index and Spectrum Efficiency with Cache Restricted for Resource Allocation in Multi-Beam Satellite Systems

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china.Communications 2019年第2期16卷 189-201页

作者： Pei Zhang Xiaohui wang Zhiguo Ma Junde Song school of Computer science Beijing University of Posts and Telecommunications china.Academy of Information and Communications Technology

Dynamic resource allocation(DRA) is a key technology to improve system performances in GEO multi-beam satellite systems. And, since the cache resource on the satellite is very valuable and limited, DRA problem under restricted cache resources is also an important issue to be studied. This paper mainly investigates the DRA problem of carrier resources under certain cache constraints. What's more, with the aim to satisfy all users' traffic demands as more as possible, and to maximize the utilization of the bandwidth, we formulate a multi-objective optimization problem(MOP) where the satisfaction index and the spectrum efficiency are jointly optimized. A modified strategy SA-NSGAII which combines simulated annealing(SA) and non-dominated sorted genetic algorithm-II(NSGAII) is proposed to approximate the Pareto solution to this MOP problem. Simulation results show the effectiveness of the proposed algorithm in terms of satisfaction index, spectrum efficiency, occupied cache, and etc.

关键词： GEO multi-beam satellite system dynamic resource allocation SA-NSGAII cache satisfaction index spectrum efficiency

Formation and causes of NOx pollution on the east side of the Taihang Mountains in china

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science Bulletin 2011年第19期 2046-2051页

作者： TIAN HeZhong 1 , wang Yan 1 , ZHAO Dan 1 , CHAI FaHe 2 , XING ZiShan 3.& CHENG Ke 1 1 State Key Joint Laboratory of Environmental Simulation & Pollution Control, school of Environment, beijing Normal {3., beijing 100875, china.2 Chinese Research Academy of Environmental sciences, beijing 100012, china.3.school of Computer science and Technology, beijing {3. of {13. and Telecommunications, beijing 100876, china

Tropospheric column amounts of NO 2 from OMI/Aura products were applied to investigate the seasonal variation of NO x on the east side of the Taihang Mountains (ESTM) in china. The NO 2 concentration varied seasonally, with winter maxima and summer minima. To explore the causes of the heavy NO 2 pollution in this region, wind field simulations were conducted by using the Fifth-Generation NCAR/Penn State Mesoscale Model (MM5). MM5 simulations showed that wind directions in the ESTM region were dominated by northeasterly and northwesterly winds throughout the year and to a lesser degree by southwesterlies. Elevated NO 2 concentrations (higher than 50×10 15 molec/cm 2 ) occurred in three meteorological situations: convergent wind fields (5 days), northeasterly winds (2 days), and calm days (1 day) in January. Although the local anthropogenic NO x emission strength was not so high as that in other developed areas, the calms and frequent occurrence of convergent wind fields, as well as unfavorable terrains for diffusion, resulted in the accumulation of atmospheric pollutants and hence heavy NO x pollution. Furthermore, long-distance NO x transportation from the beijing-Tianjin-Tangshan region to the ESTM area could be seen when the wind was from a northeasterly direction, especially under high wind speeds.

关键词： east side of the Taihang Mountains (ESTM) remote sensing of air pollution satellite data tropospheric NO 2 pollution wind field china