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Cross-subcarrier precoder design for massive MIMO-OFDM downlink with symplectic optimization

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Science China(Information Sciences) 2025年第2期68卷 216-229页

作者： Yuxuan ZHANG An-An LU Xiang-Gen XIA Xiqi GAO national Mobile Communications research Laboratory Southeast University Purple Mountain Laboratories Department of Electrical and Computer Engineering University of Delaware

We propose a cross-subcarrier precoder design(CSPD) for massive multiple-input multiple-output(MIMO) orthogonal frequency division multiplexing(OFDM) downlink. This work aims to significantly improve the channel estimation and signal detection performance by enhancing the smoothness of the frequency domain effective channel. This is accomplished by designing a few vectors known as the transform domain precoding vectors(TDPVs), which are then transformed into the frequency domain to generate the precoders for a set of subcarriers. To combat the effect of channel aging, the TDPVs are optimized under imperfect channel state information(CSI). The optimal precoder structure is derived by maximizing an upper bound of the ergodic weighted sum-rate(WSR) and utilizing the a posteriori beam-based statistical channel model(BSCM). To avoid the large-dimensional matrix inversion, we propose an algorithm with symplectic optimization. Simulation results indicate that the proposed cross-subcarrier precoder design significantly outperforms conventional methods.

关键词： massive MIMO-OFDM cross subcarrier precoder design transform domain precoding vectors effective channel symplectic optimization

Software-defined process-near-memory architecture using 3D hybrid bonding integration

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Science China(Information Sciences) 2025年第1期68卷 366-378页

作者： Anlin XU Chenchen DENG Jianfeng ZHU Yao WANG Shaojun WEI Leibo LIU School of Integrated Circuits Tsinghua University Beijing Institution of Tracking and Communication Technology Beijing national research Center for Information Science and Technology Tsinghua University

With the unprecedented explosive growing amount of global data, the development of computing chips, which encounter bottlenecks such as power wall and memory wall, cannot satisfy the demanding requirement. This work proposes a software-defined process-near-memory(SDPNM) computing architecture implemented using 3D hybrid bonding *** software-defined chip architecture, featuring spatial computations and dynamic reconfiguration, innovates in a top-down manner to achieve high energy efficiency while maintaining flexibility after fabrication. The process-near-memory integration further advances the SDNPM chip in a bottom-up way to reduce the energy consumption of data movement while improving the bandwidth. Utilizing a relatively mature fabrication and bonding process can result in feasible solutions for both data-intensive and compute-intensive applications including digital signal processing and artificial intelligence. The logic die is fabricated in the SMIC 40 nm process and the DRAM die is fabricated in the PSMC 25 nm process. The hybrid bonding is implemented by XMC. The experimental results show that the energy efficiency of the proposed SDPNM chip is 33.1× better than the state-of-the-art FPGA ranging from 8.2× to 104.1×.

关键词： software-defined chips process near memory energy efficiency dynamic reconfiguration domain specific

Substrate bias effects in p-channel GaN-on-Si transistors

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Science China(Information Sciences) 2025年第1期68卷 404-405页

作者： Mengyao ZHAO Jie MA Lanlan YANG Chuanqi PAN Denggui WANG Jianjun ZHOU Sheng LI Jiaxing WEI Long ZHANG Siyang LIU Weifeng SUN national ASIC System Engineering research Center School of Integrated Circuits Southeast University national Center of Technology Innovation for Electronic Design Automation Southeast University national Key Laboratory of Solid-State Microwave Devices and Circuits

The drain current （ID） of the n-channel GaN field-effecttransistor （n-FET） is influenced by the substrate-to-source bias voltage (VBS)（substrate bias effect）[1].Actually,nonzero VBSis also likely to occur in p-FET in real application,because the source electrode of p-FET is usually connected to high *** study reports the dependency between IDand VBSin p-FET for the first time,and analyzes the underlying mechanisms from the perspective of vertical electric field （EF） distribution.

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Secure beamforming and deployment design for rate-splitting multiple access-based UAV communications

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Science China(Information Sciences) 2025年第1期68卷 342-356页

作者： Bing WANG Xiaofeng TAO Shujun HAN Huici WU Kai YANG Zhu HAN national Engineering research Center of Mobile Network Technologies Beijing University of Posts and Telecommunications Peng Cheng Laboratory Department of Electrical and Computer Engineering University of Houston

Rate-splitting multiple access(RSMA) has recently gained attention as a potential robust multiple access(MA)scheme for upcoming wireless networks. Given its ability to efficiently utilize wireless resources and design interference management strategies, it can be applied to unmanned aerial vehicle(UAV) networks to provide convenient services for large-scale access ground users. However, due to the line-of-sight(LoS) broadcast nature of UAV transmission, information is susceptible to eavesdropping in RSMA-based UAV networks. Moreover, the superposition of signals at the receiver in such networks becomes complicated. To cope with the challenge, we propose a two-user multi-input single-output(MISO) RSMA-based UAV secure transmission framework in downlink communication networks. In a passive eavesdropping scenario, our goal is to maximize the sum secrecy rate by optimizing the transmit beamforming and deployment location of the UAV-base station(UAV-BS),while considering quality-of-service(QoS) constraints, maximum transmit power, and flight space limitations. To address the non-convexity of the proposed problem, the optimization problem is first decoupled into two subproblems. Then, the successive convex approximation(SCA) method is employed to solve each subproblem using different propositions. In addition, an alternating optimization(AO)-based location RSMA(L-RSMA) beamforming algorithm is developed to implement joint optimization to obtain the suboptimal solution. Numerical results demonstrate that(1) the proposed L-RSMA scheme yields a28.97% higher sum secrecy rate than the baseline L-space division multiple access(SDMA) scheme;(2) the proposed L-RSMA scheme improves the security performance by 42.61% compared to the L-non-orthogonal multiple access(NOMA) scheme.

关键词： rate-splitting multiple access UAV communication precoding optimization deployment location physical layer security

Personalized federated few-shot node classification

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Science China(Information Sciences) 2025年第1期68卷 204-218页

作者： Yunfeng ZHAO Xintong HE Guoxian YU Jun WANG Yongqing ZHENG Carlotta DOMENICONI School of Software Shandong University Joint SDU-NTU Centre for Artificial Intelligence research Shandong University Department of Mathematics National University of Singapore Department of Computer Science George Mason University

Personalized federated learning(PFL) aims to train customized models for individual clients in a decentralized setting, with the account of non-independent and identically distributed data across clients. However, most PFL methods adopt uniform classification layers for diverse clients and give rise to error-prone predictions, due to the task heterogeneity notably prominent in decentralized graph data scenarios. Although some PFL solutions setup client-specific classification layers for each client and optimize them only locally, they are corrupted with limited local training data. We propose an innovative solution called federated parameter decoupling and node augmentation(Fed PANo) to address these problems and to achieve personalized federated few-shot node classification, which is a prevalent and challenging but unexplored topic. Specifically, Fed PANo first separates the local model into the GNN and classifier to handle unique client-specific task variations. The GNN is trained through federated learning to capture shared knowledge of graph nodes across clients, while the classifier is custom-designed and trained individually for each client. Additionally, a generic classifier shared among clients is adopted to encourage the GNN's grasp of shared information. Then Fed PANo further proposes the node generator along with its local and collaborative training strategies to deal with the node scarcity of clients. Extensive experimental results on benchmark datasets confirm that Fed PANo outperforms eight competitive baselines across different settings.

关键词： personalized federated learning few-shot learning node classification task heterogeneity parameter decoupling node augmentation

Leveraging ROTI map derived from Indonesian GNSS receiver network for advancing study of Equatorial Plasma Bubble in Southeast/East Asia

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Earth and Planetary Physics 2025年第1期9卷 101-116页

作者： Prayitno Abadi Ihsan N.Muafiry Teguh N.Pratama Angga Y.Putra Suraina Gatot H.Pramono Sidik T.Wibowo Febrylian F.Chabibi Umar A.Ahmad Wildan P.Tresna Asnawi research Center for Climate and Atmosphere Indonesian National Research and Innovation Agency(BRIN)BandungIndonesia School of Electrical Engineering Telkom UniversityBandungIndonesia Directorate of Laboratory Management Facilities and Science and Technology Park Indonesian National Research and Innovation Agency(BRIN)PontianakIndonesia Geophysics Laboratory Master Program in PhysicsUniversitas Gadjah Mada(UGM)YogyakartaIndonesia research Center for Space Indonesian National Research and Innovation Agency(BRIN)BandungIndonesia Indonesian Geospatial Information Agency(BIG) JakartaIndonesia research Center for Photonics Indonesian National Research and Innovation Agency(BRIN)Tangerang SelatanIndonesia Department of Earth and Planetary Sciences Hokkaido UniversitySapporoJapan

This paper highlights the crucial role of Indonesia’s GNSS receiver network in advancing Equatorial Plasma Bubble(EPB)studies in Southeast and East Asia,as ionospheric irregularities within EPB can disrupt GNSS signals and degrade positioning *** by the Indonesian Geospatial Information Agency(BIG),the Indonesia Continuously Operating Reference Station(Ina-CORS)network comprises over 300 GNSS receivers spanning equatorial to southern low-latitude ***-CORS is uniquely situated to monitor EPB generation,zonal drift,and dissipation across Southeast *** provide a practical tool for EPB research,by sharing two-dimensional rate of Total Electron Content(TEC)change index(ROTI)derived from this *** generate ROTI maps with a 10-minute resolution,and samples from May 2024 are publicly available for further scientific *** preliminary findings from the ROTI maps of Ina-CORS are ***,the Ina-CORS ROTI maps reveal that the irregularities within a broader EPB structure persist longer,increasing the potential for these irregularities to migrate farther ***,we demonstrate that combined ROTI maps from Ina-CORS and GNSS receivers in East Asia and Australia can be used to monitor the development of ionospheric irregularities in Southeast and East *** have demonstrated the combined ROTI maps to capture the development of ionospheric irregularities in the Southeast/East Asian sector during the G5 Geomagnetic Storm on May 11,*** observed simultaneous ionospheric irregularities in Japan and Australia,respectively propagating northwestward and southwestward,before midnight,whereas Southeast Asia’s equatorial and low-latitude regions exhibited irregularities *** sharing ROTI maps from Indonesia and integrating them with regional GNSS networks,researchers can conduct comprehensive EPB studies,enhancing the understanding of EPB behavior across Southeast and East Asia and contributing significantly to ionosphe

关键词： Equatorial Plasma Bubble(EPB) GNSS receivers’network Indonesia Continuously Operating Reference Station(Ina-CORS) ionospheric map Rate of TEC change index(ROTI)map

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Managing virus diseases in citrus:Leveraging high-throughput sequencing for versatile applications

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Horticultural Plant Journal 2025年第1期11卷 57-68页

作者： Hongming Chen Zhiyou Xuan Lu Yang Song Zhang Mengji Cao Integrative Science Center of Germplasm Creation in Western China(Chongqing)Science City Citrus Research InstituteSouthwest UniversityChongqing 400712China national Citrus Engineering research Center Citrus Research InstituteSouthwest UniversityChongqing 400712China

In this review,the advantages and advances in applying high-throughput sequencing(HTS)in the management of viral diseases in citrus,along with some challenges,are discussed to provide perspectives on future *** the initial implementation of HTS in citrus virology,a substantial number of citrus viruses have been identified,with a notable increase in the last 7 *** acquisition of viral genomes and various HTS-based omics analyses serve as crucial pillars for advancing research in the etiology,epidemiology,pathology,evolution,ecology,and biotechnology of citrus *** has notably contributed to disease diagnosis,such as the diagnoses of concave gum and impietratura,as well as to the surveillance of new virus risks and the preparation of virus-free ***,certain inherent defects in HTS and coupled bioinformatics analysis,such as challenges with sequence assembly and the detection of viral dark matter,require improvement to enhance practical *** addition,the utilization of HTS for the systematic management of citrus viral diseases remains limited,and drawing insights from other virus-plant pathosystems while integrating emerging compatible techniques and ideas may broaden its specific applications.

关键词： Deep sequencing Virus epidemics Functional genomics CRISPR/Cas Virus-host interactions

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Subsection cooling system of hot rolling silicon steel and its industrial application

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Journal of Iron and Steel research International 2025年第1期32卷 159-170页

作者： Qiu-na Wang Ji-quan Sun Li-po Yang Hai-shen Wang Li-jie Dong Jie-ming Li Zhen-yang Zhi Yan-wen Bi national Engineering research Center of Flat Rolling Equipment University of Science and Technology BeijingBeijing100083China Hot Rolling Department of Qian’an Iron and Steel Corporation Shougang Company LimitedTangshan064404HebeiChina national Engineering research Center for Equipment and Technology of Cold Strip Rolling Yanshan UniversityQinhuangdao066004HebeiChina

An online subsection cooling method for hot rolling silicon steel was designed to achieve local adjustment of transverse roll ***,it was able to meet the requirements of edge drop of the strip by using the features of online thermal ***,after the new subsection spray beam was installed at the exit of mill,the special local cooling rules were analyzed for altering the thermal crown of roll according to rolling process ***,the dynamic impact of subsection cooling on the local thermal crown could just be obtained according to the measured ***,the heat transfer coefficient was determined by different subsection cooling curves under varied rolling ***,the rolling rhythm and variable conditions were important dynamic factors of transient roll temperature in practical rolling ***,real-time calculation and presetting of the thermal crown were carried out to maximize special requirements of load roll gap on local strip *** this new method,the transient temperature and the thermal crown of roll could be quantitatively controlled *** the practical results showed that the predicted temperature was able to match the measured value by more than 95%.Meanwhile,the adjustable range of thermal crown increased by more than 2.5 ***,the qualification rate of strip edge crown has increased from the original 30%to over 70%.

关键词： Subsection cooling Thermal roll crown Multi-parameter coupling Hot rolling Silicon steel

Influence of phytoplankton,bacteria and viruses on nutrient supply in tropical waters

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Journal of Environmental Sciences 2025年第5期151卷 174-186页

作者： Zhi Yang Sim Kwan Chien Goh Nur Hanisah binte Sukarji Feijian Mao Yiliang He Karina Yew-Hoong Gin national university of Singapore Environmental research Institute National University of Singapore1 Create Way#15-02Singapore 138602Singapore Institute of Tibetan Plateau research Chinese Academy of Sciences(CAS)Beijing 100101China School of Environmental Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China Department of Civil and Environmental Engineering National University of SingaporeBlk E1A-07-031 Engineering Drive 2Singapore 117576Singapore

Diel investigations of water environments are one means to holistically understand the dynamics and functional roles of phytoplankton,bacteria and viruses in these *** have the potential to substantially impact carbon(C),nitrogen(N)and phosphorus(P)biogeochemistry through their respective *** study characterizes the phytoplankton,bacteria and virus communities and the elemental composition of various C,N and P nutrients flow over three diel cycles in tropical urban *** results show that ratios of C:N:P fluctuated strongly from the lack of dissolved organic phosphorus(DOP)and PO_(4).Specifically,green algae peaked during day time and exudate dissolved organic matter(DOM)that strongly modulate dissolved organic carbon(DOC):DOP ratio to diel DOP *** linear regression and Stella modelling emphasize the roles of viruses together with Synechococcus as important nutrient recyclers of NH_(4)and PO_(4)in nutrients-limited *** normalised surface PO_(4)and combined surface and bottom NH_(4)concentration selected both viruses and Synechococcus as important *** model of N and P biogeochemical cycles can achieve 69%and 57%similar to observed concentration of NH_(4)and PO_(4),respectively.A short latent period of 9 hr was calculated,in addition to the calibrated high infectivity of viruses to *** together,the rapid turn-over between Synechococcus and viruses has biogeochemical significance,where the rapid recycling of essential nutrients allows for shortcuts in the N and P cycle,supporting a wide range of microbes.

关键词： Diel Phytoplankton Bacteria Virus Nutrients Element ratios