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

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

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Study on the influences of ionization region material arrangement on Hall thruster channel discharge characteristics

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Plasma science and Technology 2018年第2期20卷 47-55页

作者：胡翔段萍宋继磊李文庆陈龙边兴宇 College of science Dalian Maritime University Transportation engineering postdoctoral research station Dalian Maritime University

There exists strong interaction between the plasma and channel wall in the Hall thruster,which greatly affects the discharge performance of the *** this paper,a two-dimensional physical model is established based on the actual size of an Aton P70 Hall thruster discharge *** particle-in-cell simulation method is applied to study the influences of segmented low emissive graphite electrode biased with anode voltage on the discharge characteristics of the Hall thruster *** influences of segmented electrode placed at the ionization region on electric potential,ion number density,electron temperature,ionization rate,discharge current and specific impulse are *** results show that,when segmented electrode is placed at the ionization region,the axial length of the acceleration region is shortened,the equipotential lines tend to be vertical with wall at the acceleration region,thus radial velocity of ions is reduced along with the wall *** axial position of the maximal electron temperature moves towards the exit with the expansion of ionization ***,the electron-wall collision frequency and ionization rate also increase,the discharge current decreases and the specific impulse of the Hall thruster is slightly enhanced.

关键词： Hall thruster segmented electrode particle-in-cell wall material

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Exploiting Pre-Trained Network Embeddings for Recommendations in Social Networks

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Journal of Computer science & Technology 2018年第4期33卷 682-696页

作者： Lei Guo Yu-Fei Wen Xin-Hua Wang postdoctoral research station of management science and engineering Shandong Normal University Jinan 250014 China School of management science and engineering Shandong Normal University Jinan 250014 China School of Information science and engineering Shandong Normal University Jinan 250014 China

Recommender systems as one of the most efficient information filtering techniques have been widely studied in recent years. However, traditional recommender systems only utilize user-item rating matrix for recommendations, and the social connections and item sequential patterns are ignored. But in our real life, we always turn to our friends for recommendations, and often select the items that have similar sequential patterns. In order to overcome these challenges, many studies have taken social connections and sequential information into account to enhance recommender systems. Although these existing studies have achieved good results, most of them regard social influence and sequential information as regularization terms, and the deep structure hidden in social networks and rating patterns has not been fully explored. On the other hand, neural network based embedding methods have shown their power in many recommendation tasks with their ability to extract high-level representations from raw data. Motivated by the above observations, we take the advantage of network embedding techniques and propose an embedding-based recommendation method, which is composed of the embedding model and the collaborative filtering model. Specifically, to exploit the deep structure hidden in social networks and rating patterns, a neural network based embedding model is first pre-trained, where the external user and item representations are extracted. Then, we incorporate these extracted factors into a collaborative filtering model by fusing them with latent factors linearly, where our method not only can leverage the external information to enhance recommendation, but also can exploit the advantage of collaborative filtering techniques. Experimental results on two real-world datasets demonstrate the effectiveness of our proposed method and the importance of these external extracted factors.

关键词： social recommendation network embedding matrix factorization item sequential pattern

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Two-Level Linear Relaxation Method for Generalized Linear Fractional Programming

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Journal of the Operations research Society of China 2023年第3期11卷 569-594页

作者： Hong-Wei Jiao You-Lin Shang postdoctoral research Base Henan Institute of Science and TechnologyXinxiang453003HenanChina postdoctoral research station of Control science and engineering Henan University of Science and TechnologyLuoyang471023HenanChina

This paper presents an efficient algorithm for globally solving a generalized linear fractional programming *** establishing this algorithm,we firstly construct a two-level linear relaxation method,and by utilizing the method,we can convert the initial generalized linear fractional programming problem and its subproblems into a series of linear programming relaxation *** on the branch-and-bound framework and linear programming relaxation problems,a branch-and-bound algorithm is presented for globally solving the generalized linear fractional programming problem,and the computational complexity of the algorithm is ***,numerical experimental results demonstrate the feasibility and efficiency of the proposed algorithm.

关键词： Generalized linear fractional programming Global optimization Two-level linear relaxation method Branch-and-bound

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RISK-SENSITIVE FIXED-POINT SMOOTHING ESTIMATION FOR LINEAR DISCRETE-TIME SYSTEMS WITH MULTIPLE OUTPUT DELAYS

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Journal of Systems science & Complexity 2013年第2期26卷 137-150页

作者： ZHAO Hongguo CUI Peng postdoctoral research station of School of Mathematics Shandong University School of Information science and Technology Taishan University School of Control science and engineering Shandong University

This paper investigates the risk-sensitive fixed-point smoothing estimation for hnear omcrete-time systems with multiple time-delay measurements. The problem considered can be converted into an optimization one in indefinite space. Then the risk-sensitive fixed-point smoother is obtained by solving the optimization problem via innovation analysis theory in indefinite space. Necessary and sufficient conditions guaranteeing the existence of the risk-sensitive smoother are also given when the risk-sensitive parameter is negative. Compared with the conventional approach, a significant advantage of presented approach is that it provides less computational cost.

关键词： Innovation Riccati equation risk-sensitive time-delay.

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Energy-Efficient User Association in Heterogeneous Networks with M2M/H2H Coexistence under QoS Guarantees

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China Communications 2015年第S1期12卷 93-103页

作者： TIAN Hui XU Youyun XU Kui JING Jun WU Kun Institute of Communication engineering PLA University of Science and Technology postdoctoral Scientific research station PLA Unit No.66393

In this paper, we propose an energy efficient user association scheme for uplink heterogeneous networks with machine-to-machine(M2M) and human-to-human(H2H) coexistence. A group based random access protocol is designed for massive number of machine-typecommunications(MTC) user equipments'(UEs) transmissions. A user association problem for UEs' energy efficiency maximization is formulated considering the HTC UEs' quality of service(QoS) guarantees and load balance among multiple BSs, simultaneously. A distributed iterative algorithm is developed to solve the optimization problem. In addition, the convergence of the proposed algorithm is proved. Simulation results show that our proposed scheme outperforms other schemes in terms of energy efficiency and QoS guarantees.

关键词： energy efficiency QoS user as sociation M2M communication heterogeneous networks

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Preparation and thixoforging of semisolid billet of AZ80 magnesium alloy

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Transactions of Nonferrous Metals Society of China 2010年第9期20卷 1731-1736页

作者：姜巨福王迎曲建俊杜之明罗守靖 School of Materials science and engineering Harbin Institute of Technology postdoctoral Mobile station of Mechanical engineering Harbin Institute of Technology School of Mechatronics engineering Harbin Institute of Technology postdoctoral Mobile station of Mechanics Harbin Institute of Technology

Semisolid billet of AZ80 magnesium alloy was prepared by new strain induced melt activated (new SIMA) process and thixoforging experiment was *** results show that after as-cast AZ80 magnesium alloy is processed by equal channel angular extrusion, microstructure is refined well due to heavy dynamic recrystallization occurring in severe plastic *** with semisolid isothermal treatment and conventional SIMA, semisolid billet with fine and spheroidal grains are achieved in new *** process of semisolid billet prepared by new SIMA has many advantages such as good surface quality of final component, high ability to fill cavity and *** fine and spheroidal grains and high mechanical properties such as tensile strength of 298 MPa and elongation of 28% can be developed in final part thixoforged.

关键词： AZ80 magnesium alloy semi-solid forming thixoforging semisolid billet strain induced melt activation

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Preparation of AZ91D magnesium alloy semi-solid billet by new strain induced melt activated method

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中国有色金属学会会刊：英文版 2006年第5期16卷 1080-1085页

作者：姜巨福罗守靖邹经湘 School of Materials science and engineering Harbin Institute of Technology postdoctoral Mobile station of Mechanics Harbin Institute of TechnologyHarbin 150001China postdoctoral Mobile station of Mechanics Harbin Institute of Technology

New strain induced melt activated (new SIMA) method for preparing AZ91D magnesium alloy semi-solid billet is introduced by applying equal channel angular extrusion into strain induced step in SIMA method, by which semi-solid billet with fine spheroidal grains and average grain size of 18 μm can be prepared. Furthermore, average grain size of semi-solid billet is reduced with increasing extrusion pass of AZ91D magnesium alloy obtained in ECAE process. By using semi-solid billet prepared by new SIMA, thixoforged magazine plates component with high mechanical properties such as yield strength of 201.4 MPa, ultimate tensile strength of 321.8 MPa and elongation of 15.3%, can be obtained.

关键词：等通道角挤压半固体坯料机械性能镁合金

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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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SYNDIOSPECIFIC POLYMERIZATION OF STYRENE WITH Ar[O,O/NH]Cp ~*TiCl ACTIVATED WITH MMAO

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Chinese Journal of Polymer science 2009年第5期27卷 659-665页

作者：陈劼 Haerbin Institute of Technology postdoctoral station of School of Materials science and engineering Daqing Oilfield Company Ltd. Exploration and Development of Research Institute

A series of titanium complexes Ar[O,E]Cp~*TiCl(Cp~*=C_5Me_5,Ar=1,2-phenylene,E=NH(1a);Ar=1,2- phenylene,E=O(1b);Ar=2.2'-diphenylene,E=O(1c);Ar=2,2'-dinaphthalene,E=O(1d)) has been prepared by the reaction of corresponding phenol derivatives with Cp~*TiCl_3 in the presence of excessive *** the conditions of low Al/Ti molar ratio(e.g.500) and high reaction temperatures(>70℃),all the titanium complexes display higher catalytic activities towards the syndiospecific polymerization of styrene,in t...

关键词： Ziegler-Natta polymerization Catalysts Syndiotactic Polystyrene.

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