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Digital AGC Based on Coherent Adjustment Cycle for DSSS Receiver

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China Communications 2015年第2期12卷 95-106页

作者： SHEN Yuyao WANG Yongqing SHENG Dewei WU Siliang School of information and Electronics Beijing Institute of Technology

In order to meet the requirements for zero value stability of direct sequence spread spectrum(DSSS) signal processing in high dynamic scenario,digital automatic gain control(AGC) is employed to regulate ***,conventional AGC causes degradation in the synchronization performance of DSSS *** on the theoretical analysis of the influence of digital AGC on DSSS signal synchronization,this paper proposes a new AGC algorithm,which is applicable to multi-channel digital DSSS signal *** making power adjustment cycle and synchronization cycle coherent with each other adaptively,the influence of digital AGC on subsequent synchronization processing has been *** analysis,simulation results and experimental data verify the validity of the proposed *** virtue of the proposed algorithm,the influence of digital AGC on DSSS signal synchronization is *** algorithm applies to an aerospace engineering project successfully.

关键词：数字AGC DSSS 扩频接收机整周期相干数字自动增益控制直接序列扩频同步性能

Properties of Linear Entropy in k-Photon Jaynes-Cummings Model with Stark Shift and Kerr-Like Medium

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Communications in Theoretical Physics 2010年第5期53卷 931-936页

作者：廖庆洪 Muhammad Ashfaq Ahmad 王月媛刘树田 Department of Physics Harbin Institute of Technology Department of Physics COMSATS Institute of Information Technology

The time evolution of the linear entropy of an atom in k-photon Jaynes-Cummings model is investigatedtaking into consideration Stark shift and Kerr-like medium. The effect of both the Stark shift and Kerr-like medium onthe linear entropy is analyzed using a numerical technique for the field initially in coherent state and in even coherentstate. The results show that the presence of the Kerr-like medium and Stark shift has an important effect on theproperties of the entropy and entanglement. It is also shown that the setting of the initial state plays a significant rolein the evolution of the linear entropy and entanglement.

关键词：斯塔克位移线性熵 Kerr介质 K光子 s模型 Stark效应属性时间演化

Improved eigenanalysis canceler based on data-independent clutter subspace estimation for space-time adaptive processing

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Science China(information Sciences) 2013年第10期56卷 1-10页

作者： LONG Teng LIU YongXu YANG XiaoPeng SUN YuZe School of information and Electronics Beijing Institute of Technology

The eigenanalysis canceler(EC)method which is suitable for nonhomogeneous clutter can suppress clutter efectively by discarding the eigenvectors of small eigenvalues,which is a well-known subspace-based space-time adaptive processing(STAP)***,the computational complexity of conventional EC STAP method is huge due to the eigenvalue ***,the corresponding performance would be degraded signifcantly by the subspace leakage phenomenon,since the clutter subspace is not strictly confned to a low-rank subspace any ***,an improved EC STAP method based on the data-independent clutter subspace estimation is proposed to reduce the computational complexity,where the clutter subspace is rapidly constructed by sampling the prolate spheroidal wave functions(PSWF)*** order to deal with the subspace leakage phenomenon,the proposed EC-PSWF STAP method is modifed based on the covariance matrix taper(CMT)to obtain the covariance matrix by re-establishing the noise *** corresponding performance of proposed method is evaluated by using the numerical simulation.

关键词： space-time adaptive processing airborne radar prolate spheroidal wave function eigenanalysis canceler clutter suppression

Energy-Efficient Transceiver Design for Multi-Pair Two-Way Relay Systems

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China Communications 2015年第9期12卷 133-140页

作者： Fei Zesong Li Na Xing Chengwen Gong Shiqi School of information and Electronics Beijing Institute of Technology

In this paper, we focus on energy-efficient transceiver and relay beamforming design for multi-pair two-way relay system. The multi-antenna users and the multi-antenna relay are considered in this work. Different from the existing works, the proposed algorithm is energy-efficient which is more applicable to the future green network. It considers both the sum-MSE problem and the power consumption problem for the users under the relay power constraint. Based on the optimal condition decomposition(OCD) method, the energy-efficient precoders at the users can be designed separately with limited information exchanged. The proposed relay beamforming algorithm is based on the alternative direction method of multipliers(ADMM) which has simpler iterative solution and enjoys good convergence. Simulation results demonstrate the performance of the proposed algorithms in terms of power consumption and MSE performance.

关键词：中继系统收发器设计波束形成算法多路高效节能交替方向法绿色网络

A new barycenter code discriminator for multi-access interference

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Science China(information Sciences) 2014年第2期57卷 113-121页

作者： WANG YongQing LI Cong XU Duo YANG Na School of information and Electronics Beijing Institute of Technology

The performance of code tracking loop in direct sequence spread spectrum system decreases because of multi-access *** order to solve this problem,this paper presents a new code discriminator based on barycenter *** calculating the barycenter of code phase by multiple PN code branches’correlation results,PN code phase error can be *** analysis of new discriminator’s performance is given,and it is indicated that the code tracking loop using this algorithm can also solve the problems of low ranging precision and large mean deviation caused by multi-access *** efciency of the proposed algorithm is verified by simulation and measurements and the new discriminator is used in an aerospace engineering project successfully.

关键词： direct sequence spread spectrum code tracking loop code discriminator barycenter tracking

Quantitative functionalization of biosynthetic caged protein materials

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Quantitative Biology 2023年第1期11卷 1-14页

作者： Quan Cheng Xuan Wang Xian-En Zhang Chengchen Xu Feng Li College of Life Sciences and Health Wuhan University of Science and TechnologyWuhan 430065China State Key Laboratory of Virology Wuhan Institute of VirologyCenter for Biosafety Mega-ScienceChinese Academy of SciencesWuhan 430071China Faculty of Synthetic Biology Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China National Laboratory of Biomacromolecules Institute of BiophysicsChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

Background:As one of the representative protein materials,protein nanocages(PNCs)are self-assembled supramolecular structures with multiple advantages,such as good monodispersity,biocompatibility,structural addressability,and facile *** quantitative functionalization is essential to the construction of PNCs with designed ***:With three modifiable interfaces,the interior surface,outer surface,and interfaces between building blocks,PNCs can serve as an ideal platform for precise multi-functionalization studies and *** review summarizes the currently available methods for precise quantitative functionalization of PNCs and highlights the significance of precise quantitative control in fabricating PNC-based materials or *** methods can be categorized into three groups,genetic,chemical,and combined ***:This review would be constructive for those who work with biosynthetic PNCs in diverse fields.

关键词： protein nanocages virus-like particles functionalization genetic modification chemical modification

Tensor-based blind signal recovery for multi-carrier amplify-and-forward relay networks

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Science China(information Sciences) 2014年第10期57卷 66-76页

作者： WANG Zuo WANG Jing XING ChengWen FEI ZeSong KUANG JingMing School of information and Electronics Beijing Institute of Technology

Cooperative communications have great potentials in performance enhancement via deploying relay nodes. However, these kinds of benefits usually come at the cost of more system parameters to be estimated. This fact definitely reduces the efficiency of wireless systems and then it motivates the research on the blind algorithms for cooperative communications that need fewer parameters. In this paper, we investigate the parallel factors(PARAFAC) decomposition-based blind signal recovery algorithm design for two-hop amplify-and-forward(AF)multi-carrier cooperative networks. In particular, the uniqueness of the PARAFAC decomposition used in the proposed algorithm is first investigated in detail, and then the performance of signal recovery is ***, the simulation results assess the performance of our proposed algorithm.

关键词： amplify-and-forward cooperative networks tensor PARAFAC decomposition signal recovery

Comments on “Distillability sudden death in qutrit qutrit systems under thermal reservoirs”

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Chinese Physics B 2014年第9期23卷 87-90页

作者： Mazhar Ali Department of Electrical Engineering COMSATS Institute of Information Technology

In a recent paper （2012 Chin. Phys. B 21 084205）, the authors studied the problem of distillability sudden death. We find that their equation of motion is incorrect and consequently the rest of the paper is wrong. Even apart from starting with a wrong equation of motion, their description of the phenomenon of distillability sudden death is totally misleading and needs to be rectified. To this aim, we show that certain initially prepared free-entangled states become bound-entangled in a finite time under thermal reservoirs. Moreover, in contrast with zero-temperature reservoirs, simple local unitary transformations cannot completely avoid distillability sudden death.

关键词： distillability thermal reservoirs bound entanglement

HAS Dynamic Buffer-Driven Resource Management to Enhance QoE in Mobile Network

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China Communications 2017年第7期14卷 11-24页

作者： Fei Wang Zesong Fei Jing Wang School of information and Electronics Beijing Institute of Technology

Hypertext transfer protocol(HTTP) adaptive streaming(HAS) plays a key role in mobile video transmission. Considering the multi-segment and multi-rate features of HAS, this paper proposes a buffer-driven resource management(BDRM) method to enhance HAS quality of experience(QoE) in mobile network. Different from the traditional methods only focusing on base station side without considering the buffer, the proposed method takes both station and client sides into account and end user's buffer plays as the drive of whole schedule process. The proposed HAS QoE influencing factors are composed of initial delay, rebuffering and quality level. The BDRM method decomposes the HAS QoE maximization problem into client and base station sides separately to solve it in multicell and multi-user video playing scene in mobile network. In client side, the decision is made based on buffer probe and rate request algorithm by each user separately. It guarantees the less rebuffering events and decides which HAS segment rate to fetch. While, in the base station side, the schedule of wireless resource is made to maximize the quality level of all access clients and decides the final rate pulled from HAS server. The drive of buffer and twice rate request schemes make BDRMtake full advantage of HAS's multi-segment and multi-rate features. As to the simulation results, compared with proportional fair(PF), Max C/I and traditional HAS schedule(THS) methods, the proposed BDRM method decreases rebuffering percent to 1.96% from 11.1% with PF and from 7.01% with THS and increases the mean MOS of all users to 3.94 from 3.42 with PF method and from 2.15 with Max C/I method. It also guarantees a high fairness with 0.98 from the view of objective and subjective assessment metrics.

关键词：动态缓冲区移动网络资源管理驱动超文本传输协议最大化问题终端用户平均方法