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Uplink transmission design for crowded correlated cell-free massive MIMO-OFDM systems

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Science China(Information Sciences) 2021年第8期64卷 127-142页

作者： Junyuan GAO Yongpeng WU yongjian wang Wenjun ZHANG Fan WEI The Department of Electronic Engineering Shanghai Jiao Tong University The National Computer Network Emergency Response Technical Team/Coordination Center of China

In cell-free massive multiple-input multiple-output(MIMO) orthogonal frequency division multiplexing(OFDM) systems, user equipments(UEs) are served by many distributed access points(APs),where channels are correlated owing to finite angle-delay spread in realistic outdoor wireless propagation environments. Meanwhile, the number of UEs is growing rapidly for future fully networked society. In this paper, we focus on the uplink transmission design in crowded correlated cell-free massive MIMO-OFDM systems with a limited number of orthogonal pilots. For the pilot transmission phase, we identify active UEs based on non-orthogonal pilot phase shift hopping patterns and non-orthogonal adjustable phase shift pilots(APSP). We derive a closed-form expression of mean square error of channel estimation(MSE-CE) and obtain an optimal condition for minimizing MSE-CE. According to this condition, the APSP set allocation scheme is proposed. Furthermore, for the data transmission, the max-min power control algorithm is devised to maximize the minimum spectral efficiency(SE) lower bound among active UEs. Simulation results indicate significant performance gains in terms of MSE-CE for the proposed APSP set allocation scheme. The proposed power control scheme can further improve the minimum SE among active UEs. Hence, they are crucial for crowded correlated cell-free massive MIMO-OFDM systems.

关键词： APSP set allocation cell-free massive MIMO-OFDM correlated channels crowded scenarios power control

Microstructure and Thermal Conductivity of As-Cast and As-Solutionized Mg–Rare Earth Binary Alloys

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Journal of Materials Science & Technology 2017年第11期33卷 1240-1248页

作者： Liping Zhong Jian Peng Song Sun yongjian wang Yun Lu Fusheng Pan State Key Laboratory of Mechanical Transmission College of Materials Science and Engineering Chongqing University Chongqing 400044 China Chongqing Academy of Science and Technology Chongqing 401127 China Graduate School & Faculty of Engineering Chiba University Chiba 263-8522 Japan

The microstructure and thermal conductivity of four groups of Mg–rare earth（RE） binary alloys（Mg–Ce,Mg–Nd, Mg–Y and Mg–Gd） in as-cast and as-solutionized states were systematically studied. Thermal conductivity was measured on a Netzsch LFA457 using laser flash method at room temperature. Results indicated that for as-cast alloys, the volume fraction of second phases increased with the increase of alloying elements. After solutionizing treatment, a part or most of second phases were dissolved in α-Mg matrix, except for Mg–Ce alloys. The thermal conductivity of as-cast and as-solutionized Mg–RE alloys decreased with the increase of concentrations. The thermal conductivity of as-solutionized Mg–Nd,Mg–Y and Mg–Gd alloys was lower than that of as-cast alloys. Thermal conductivity of as-solutionized Mg–Ce alloys was higher than that of as-cast alloys, because of the elimination of lattice defects and fine dispersed particles during solutionizing treatment. Different RE elements have different influences on the thermal conductivity of Mg alloys in the following order： Ce 〈 Nd 〈 Y 〈 Gd. Ce has the minimum effect on thermal conductivity of Mg alloys, because of the very low solubility of Ce in the α-Mg matrix. The variations in the atomic radius of the solute elements with Mg atom（ r）, valence, configuration of extranuclear electron of the solute atoms, and the maximum solid solubility of elements in the α-Mg matrix were suggested to be the main reasons for the differences in thermal conductivity of resulting Mg–RE alloys.

关键词： Mg alloys Rare earth elements Microstructure Thermal conductivity

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Error exponent for concatenated codes in DNA data storage under substitution errors

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Science China(Information Sciences) 2022年第5期65卷 289-290页

作者： Yuxuan SHI Shuo SHAO Xiaohang ZHANG yongjian wang Yongpeng WU School of Cyber and Engineering Shanghai Jiao Tong University The National Computer Network Emergency Response Technical Team Coordination Center of China Department of Electronic Engineering Shanghai Jiao Tong University

Dear editor,The idea to store information on DNA has gained significant attention, due to the explosion of the demand for current data centers and storage techniques in recent years. DNA molecules are well known for t... 详细信息

关键词： DNA data storage substitution errors concatenated codes error exponent polar codes

New method for the preparation of adsorbent with high adsorption capacity

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Chinese Science Bulletin 2005年第21期50卷 2432-2435页

作者： wang yongjian LIU Jianfeng DUO Jia YU Yaoting Key Laboratory of Bioactive Materials Ministry of Education Nankai University Tianjin 300071 China

Polyamidoamine (PAMAM) is a type of macro- molecule having a definite chemical structure and a large number of terminal functional groups. The synthetic ap-proach of the adsorbent with high adsorption capacity in-volved arching of PAMAM onto cellulose beads by reaction with epichlorohydrin. The product thus prepared had a large number of amino groups of 2.94 mmol/g derived from 0.23 mmol/g epoxy groups on cellulose beads. This method pre-sents an effective method for the preparation of high-loading adsorbents.

关键词： PAMAM 高分子化合物化学结构吸附性纤维素

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Optimization of the cylindrical sieves for separating threshed rice mixture using EDEM

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International Journal of Agricultural and Biological Engineering 2022年第2期15卷 236-247页

作者： Jianbo Yuan Jufei wang Hua Li Xindan Qi yongjian wang Chao Li School of Mechanical Engineering University of Science and Technology BeijingBeijing 100083China School of Mechanical and Power Engineering Nanjing Tech UniversityNanjing 211816China Key Laboratory of Intelligent Agricultural Equipment in Jiangsu Province/Nanjing Agricultural University Nanjing 210031China

The design of the cylindrical sieve equipment used for the screening and separation of agricultural granular materials is mainly through the experimental method,which has the disadvantages of a long development cycle and high *** solve this problem,the discrete element method(DEM)was utilized to accurately build the particle models of threshed rice components(grains,shriveled grains,and short stalks),and simulated the separation of grains from the mixture in a cylindrical *** influences of rotational speed(A),cylindrical sieve diameter(B),cylindrical sieve aperture(C),and inclinational angle(D)on screening cleaning rate,screening loss rate,and screening efficiency were ***,the optimal parameters of the cylindrical sieve were obtained using a central composite design(CCD)under response surface methodology(RSM).The results of CCD showed that the quadratic multinomial model is credible and revealed that the cylindrical sieve aperture has a significant impact on the screening *** is predicted that the optimal values for screening cleaning rate,loss rate,and efficiency were 97.84%,0.27%,and 85.38%,respectively,while A,B,C,and D were 23.6 r/min,297 mm,8.7 mm,and 2°,*** experimental results using a real threshed rice mixture were found to be in good agreement with the optimal simulation *** study proved a reliable research method and provides a design reference for the cylinder sieving systems for threshed rice or separation of other bulk material.

关键词： cylindrical sieve threshed rice mixture discrete element method separation rice optimization

MVS-Pheno:A Portable and Low-Cost Phenotyping Platform for Maize Shoots Using Multiview Stereo 3D Reconstruction

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Plant Phenomics 2020年第1期2卷 40-56页

作者： Sheng Wu Weiliang Wen yongjian wang Jiangchuan Fan Chuanyu wang Wenbo Gou Xinyu Guo Beijing Research Center for Information Technology in Agriculture Beijing 100097China National Engineering Research Center for Information Technology in Agriculture Beijing 100097China Beijing Key Lab of Digital Plant Beijing 100097China

Plant phenotyping technologies play important roles in plant research and *** phenotypes of individual plants can guide the optimization of shoot architecture for plant breeding and are useful to analyze the morphological differences in response to environments for crop ***,high-throughput phenotyping technologies for individual plants grown in field conditions are urgently needed,and MVS-Pheno,a portable and low-cost phenotyping platform for individual plants,was *** platform is composed of four major components:a semiautomatic multiview stereo(MVS)image acquisition device,a data acquisition console,data processing and phenotype extraction software for maize shoots,and a data management *** platform’s device is detachable and adjustable according to the size of the target *** sequences for each maize shoot can be captured within 60-120 seconds,yielding 3D point clouds of shoots are reconstructed using MVS-based commercial software,and the phenotypic traits at the organ and individual plant levels are then extracted by the *** correlation coefficient(R^(2))between the extracted and manually measured plant height,leaf width,and leaf area values are 0.99,0.87,and 0.93,respectively.A data management system has also been developed to store and manage the acquired raw data,reconstructed point clouds,agronomic information,and resulting phenotypic *** platform offers an optional solution for high-throughput phenotyping of field-grown plants,which is especially useful for large populations or experiments across many different ecological regions.

关键词： breeding Stereo yielding

Response of clonal plasticity of Fargesia nitida to different canopy conditions of subalpine coniferous forest

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Frontiers in Biology 2008年第4期3卷 463-469页

作者： Jianping TAO Lixia SONG yongjian wang Weiyin ZHANG Key Laboratory of Eco-environments in Three Gorges Reservoir Region(Ministry of Education) School of Life ScienceSouthwest UniversityChongqing 400715China Institute of Forest Ecology Environment and ProtectionChinese Academy of ForestryBeijing 100091China

The aim of this study is to explore the effects of canopy conditions on clump and culm numbers,and the morphological plasticity and biomass distribution patterns of the dwarf bamboo species Fargesia ***,we investigated the effects of canopy conditions on the growth and morphological characteristics of ***,and the adaptive responses of *** to different canopy conditions and its ecological *** results indicate that forest canopy had a significant effect on the genet density and culm number per clump,while it did not affect the ramet *** tended to be few and large in gaps and forest edge plots,and small under forest understory *** ramets showed an even distribution under the closed canopy,and cluster distribution under gaps and forest edge *** forest canopy had a significant effect on both the ramets’biomass and biomass *** light conditions promoted ramet growth and biomass *** amounts of biomass in gaps and forest edge plots were shown by the higher number of culms per clump and the diameter of these *** closed canopy,the bamboos increased their branching angle,leaf biomass allocation,specific leaf area and leaf area ratio to exploit more favourable light conditions in these *** spacer length,specific spacer length and spacer branching angles all showed significant differences between gaps and closed canopy *** larger specific spacer length and spacer branching angle were beneficial for bamboo growth,scattering the ramets and exploiting more favourable light *** summary,this study shows that to varying degrees,*** exhibits both a wide ecological amplitude and high degree of morphological plasticity in response to differing forest canopy ***,the changes in plasticity enable the plants to optimize their light usage efficiency to promote growth and increase access to resources available in heterogeneous light environments.

关键词： Fargesia nitida clonal plant plasticity subalpine coniferous forest Wolong Nature Reserve

Effects of Region and Elevation on Adaptation of Leaf Functional Traits of an Invasive Plant Erigeron annuus in China

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Phyton-International Journal of Experimental Botany 2022年第1期91卷 115-128页

作者： Yuanyuan Liu Zhen Li Lie Xu Qiang Fu yongjian wang College of Horticulture&Forestry Sciences Hubei Engineering Technology Research Center for Forestry InformationHuazhong Agricultural UniversityWuhan430070China

A key scientific challenge relating to the threat of invasive plants on agriculture at the region level is to understand their adaptation and evolution in functional *** functional traits,related to growth and resource utilization,might lead to adaptation of invasive plants to the geographical barriers(region or elevation).In the field experiment,we discussed the effects of region and elevation on leaf functional traits on invasive plant Erigeron annuus in farmland habitats in *** compared leaf size,coefficient of variation(CV)of leaf traits,and fluctuating asymmetry(FA)of *** from three regions(east *** ***)and two leaf types(vegetative *** leaf),and from nine elevations(980-2100 m)in the west region of *** results indicated region and leaf type influenced leaf functional traits,and leaf size was significantly higher and CV of leaf traits and FA in reproductive leaves were significantly lower in the east region than in the west and center *** and leaf type affected leaf functional traits,and leaf size was significantly higher and CV of leaf traits in reproductive leaves were significantly lower in moderate *** has higher leaf size and developmental stability(lower CV and FA)in the eastern region due to the longer adaptation ***,leaf functional traits play an important role in the adaptation of different longitudes and *** can also facilitate the understanding of the invasiveness and adaptation of leaf traits of invasive plants in the agricultural ecosystem during their spread process in China.

关键词： Invasive alien plants(IAS) leaf traits coefficient of variation fluctuating asymmetry developmental stability

Distributed Key Management Scheme against Sybil Attacks of Wireless Sensor Network

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China Communications 2012年第5期9卷 55-63页

作者： Xu Junfeng wang yongjian Coordinat Ctr China Natl Comp Network Emergency Tech Team Beijing 100029 Peoples R China

Wireless sensor network nodes （WSN nodes） have limited computing power, storage ca-pacity, conmmunication capabilities and energy and WSN nodes are easy to be paralyzed by Sybil at- tack. In order to prevent Sybil attacks, a new key distribution scheme for wireless sensor networks is presented. In this scheme, the key inforrmtion and node ID are associated, and then the attacker is dif-ficult to forge identity ID and the key inforrmtion corresponding to ID can not be forged. This scheme can use low-power to resist the Syhil attack and give full play to the resource advantages of the cluster head. The computing, storage and corrn^ni- cation is rminly undertaken by the cluster head o- verhead to achieve the lowest energy consumption and resist against nodes capture attack. Theoretical analysis and experimental results show that com- pared with the traditional scheme presented in Ref. [14], the capture rate of general nodes of cluster re-duces 40%, and the capture rate of cluster heads reduces 50%. So the scheme presented in this pa-per can improve resilience against nodes capture at- tack and reduce node power consumption.

关键词： WSN sybil attack key distribution cluster

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