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Atomically dispersed Mn-N_(x) catalysts derived from Mn-hexamine coordination frameworks for oxygen reduction reaction
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作者 Guoyu Zhong Liuyong Zou +10 位作者 Xiao Chi Zhen Meng Zehong Chen Tingzhen Li Yongfa Huang Xiaobo Fu Wenbo Liao Shaona Zheng yongjun xu Feng Peng Xinwen Peng 《Carbon Energy》 SCIE EI CAS CSCD 2024年第5期114-126,共13页
Metal-organic frameworks recently have been burgeoning and used as precursors to obtain various metal-nitrogen-carbon catalysts for oxygen reduction reaction(ORR).Although rarely studied,Mn-N-C is a promising catalyst... Metal-organic frameworks recently have been burgeoning and used as precursors to obtain various metal-nitrogen-carbon catalysts for oxygen reduction reaction(ORR).Although rarely studied,Mn-N-C is a promising catalyst for ORR due to its weak Fenton reaction activity and strong graphitization catalysis.Here,we developed a facile strategy for anchoring the atomically dispersed nitrogen-coordinated single Mn sites on carbon nanosheets(MnNCS)from an Mn-hexamine coordination framework.The atomically dispersed Mn-N_(4) sites were dispersed on ultrathin carbon nanosheets with a hierarchically porous structure.The optimized MnNCS displayed an excellent ORR performance in half-cells(0.89 V vs.reversible hydrogen electrode(RHE)in base and 0.76 V vs.RHE in acid in half-wave potential)and Zn-air batteries(233 mW cm^(−2)in peak power density),along with significantly enhanced stability.Density functional theory calculations further corroborated that the Mn-N_(4)-C(12)site has favorable adsorption of*OH as the rate-determining step.These findings demonstrate that the metal-hexamine coordination framework can be used as a model system for the rational design of highly active atomic metal catalysts for energy applications. 展开更多
关键词 carbon nanosheets ELECTROCATALYST metal-organic frameworks Mn-N_(4) oxygen reduction reaction Zn-air batteries
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奥运文献遗产研究进展 被引量:3
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作者 徐拥军 王馨艺 《北京档案》 北大核心 2019年第8期6-10,共5页
文章通过文献检索和统计结果,分析了奥运文献遗产的源流、内涵与范围、特点与价值、利用与发展,提出加强奥运文献遗产基础理论研究,把握北京冬奥会文献遗产研究方向,注重多学科多方法综合研究等方面的内容,以期为北京2022年冬奥会文献... 文章通过文献检索和统计结果,分析了奥运文献遗产的源流、内涵与范围、特点与价值、利用与发展,提出加强奥运文献遗产基础理论研究,把握北京冬奥会文献遗产研究方向,注重多学科多方法综合研究等方面的内容,以期为北京2022年冬奥会文献遗产的保护与传承提供指导与借鉴。 展开更多
关键词 奥运会 文献遗产 奥运遗产
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The Differences in Alcohol Use between Urban and Rural Students of Inner Mongolia Medical University, China
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作者 Zhihui Hao Peng Qin +6 位作者 yongjun xu Qingxia Wang Hairong Zhang Yun Li Yueling Hu Xiaodong Bi Juan Sun 《Open Journal of Epidemiology》 2016年第2期140-145,共6页
Objective: The purpose of this study was to evaluate the difference in alcohol use between urban and rural students of Inner Mongolia Medical University. Methods: A cross-sectional census was conducted on medical stud... Objective: The purpose of this study was to evaluate the difference in alcohol use between urban and rural students of Inner Mongolia Medical University. Methods: A cross-sectional census was conducted on medical students on campus in 2013. We use multivariate logistic regression models to assess the factors associated with alcohol use. We further use chi-square test assess on differences in alcohol use between urban and rural people among significance factors in logistic regression models. Results: The prevalence of alcohol use among students in rural area was higher than that in urban area (p = 0.016). Alcohol use was associated with Gender, monthly expenses, residence, ethnic and faculty. The odds of alcohol use for Mongolia students were 1.139 times higher than that for Han students. The prevalence of alcohol consumption among students from pharmacy or Traditional Chinese Medicine and Mongolian Medicine faculties in rural area was higher than that among student in urban area (p = 0.03;p = 0.001). The prevalence of alcohol use among female students in rural area was higher than that among female students in urban area (p < 0.043). The proportion of alcohol use among students with <600 in rural area was higher than that among students in urban area (p < 0.001). Conclusion: Considering the differences in the prevalence of alcohol use between rural area and urban area, university administrators aiming at students from various regions develop various approaches. 展开更多
关键词 Alcohol Use URBAN RURAL Medical Students
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Optimal Power Allocation for Multiuser OFDM-Based Cognitive Heterogeneous Networks 被引量:6
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作者 yongjun xu Yuan Hu +1 位作者 Qianbin Chen Shun Zhang 《China Communications》 SCIE CSCD 2017年第9期52-61,共10页
Heterogeneous network(HetNet) as a promising technology to improve spectrum efficiency and system capacity has been concerned by many scholars, which brings huge challenges for power allocation and interference manage... Heterogeneous network(HetNet) as a promising technology to improve spectrum efficiency and system capacity has been concerned by many scholars, which brings huge challenges for power allocation and interference management in multicell network structures. Although some works have been done for power allocation in heterogeneous femtocell networks, most of them focus centralized schemes for single-cell network under interference constraint of macrocell user. In this paper, a sum-rate maximization based power allocation algorithm is proposed for a downlink cognitive Het Net with one macrocell network and multiple microcell networks. The original power allocation optimization problem with the consideration of cross-tier interference constraint, maximum transmit power constraint of microcell base station and inter-cell interference of microcell networks is converted into a geometric programming problem which can be solved by Lagrange dual method in a distributed way. Simulation results demonstrate the performance and effectiveness of the proposed algorithm by comparing with the equal power allocation scheme. 展开更多
关键词 COGNITIVE HETEROGENEOUS net-works power ALLOCATION GEOMETRIC program-ming LAGRANGE dual method
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Linear Pulse-Coupled Oscillators Model¬—A New Approach for Time Synchronization in Wireless Sensor Networks 被引量:4
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作者 Zhulin An Hongsong Zhu +3 位作者 Meilin Zhang Chaonong xu yongjun xu Xiaowei Li 《Wireless Sensor Network》 2010年第2期108-114,共7页
Mutual synchronization is a ubiquitous phenomenon that exists in various natural systems. The individual participants in this process can be modeled as oscillators, which interact by discrete pulses. In this paper, we... Mutual synchronization is a ubiquitous phenomenon that exists in various natural systems. The individual participants in this process can be modeled as oscillators, which interact by discrete pulses. In this paper, we analyze the synchronization condition of two- and multi-oscillators system, and propose a linear pulse-coupled oscillators model. We prove that the proposed model can achieve synchronization for almost all conditions. Numerical simulations are also included to investigate how different model parameters affect the synchronization. We also discuss the implementation of the model as a new approach for time synchronization in wireless sensor networks. 展开更多
关键词 SYNCHRONIZATION Biologically Inspired ALGORITHMS Pulse-Coupled Oscillators WIRELESS Sensor Networks
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Resource allocation for sum-rate maximization in NOMA-based generalized spatial modulation 被引量:1
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作者 Guoquan Li Zijie Hong +2 位作者 Yu Pang yongjun xu Zhengwen Huang 《Digital Communications and Networks》 SCIE CSCD 2022年第6期1077-1084,共8页
The Multiple-Input Multiple-Output(MIMO)Non-Orthogonal Multiple Access(NOMA)based on Spatial Modulation(SM-MIMO-NOMA)system has been proposed to achieve better spectral efficiency with reduced radio frequency chains c... The Multiple-Input Multiple-Output(MIMO)Non-Orthogonal Multiple Access(NOMA)based on Spatial Modulation(SM-MIMO-NOMA)system has been proposed to achieve better spectral efficiency with reduced radio frequency chains comparing to the traditional MIMO-NOMA system.To improve the performance of SM-MIMO-NOMA systems,we extend them to generalized spatial modulation scenarios while maintaining moderate complexity and fairness.In this paper,system spectral efficiency and transmission quality improvements are proposed by investigating a sum-rate maximization resource allocation problem that is subject to the total transmitted power,user grouping,and resource block constraints.To solve this non-convex and difficult problem,a graph-based user grouping strategy is proposed initially to maximize the mutual gains of intragroup users.An auxiliary-variable approach is then adopted to transform the power allocation subproblem into a convex one.Simulation results demonstrate that the proposed algorithm has better performance in terms of bit error rate and sum rates. 展开更多
关键词 Resource allocati on NOMA Spatial modulati on Power allocation User grouping
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Osteoinduction and Osteoconduction with Porous Beta-Tricalcium Phosphate Implanted after Fibular Resection in Humans 被引量:1
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作者 Takashi Ariizumi Hiroyuki Kawashima +7 位作者 Hiroshi Hatano Tetsuro Yamagishi Naoki Oike Taro Sasaki Hajime Umezu yongjun xu Naoto Endo Akira Ogose 《Journal of Biomaterials and Nanobiotechnology》 2019年第3期159-173,共15页
Osteoinductive properties of β-TCP remain unknown in humans. It is important to improve the bone grafts which have been the standard treatment for bone defect due to their biocompatibility and bone-healing properties... Osteoinductive properties of β-TCP remain unknown in humans. It is important to improve the bone grafts which have been the standard treatment for bone defect due to their biocompatibility and bone-healing properties. The purpose of this study was to radiologically clarify the bone forming property of β-TCP by evaluating the replacement of β-TCP by newly formed bone in the defect after fibular resection and to examine the histological features of a β-TCP specimen three months after grafting. Radiographs of 17 patients who underwent β-TCP grafting were evaluated. Osteoinductive and osteoconductive properties were assessed by examining bone formation from the remnant fibula, periosteum, and β-TCP alone. In one case, β-TCP was removed later because of postoperative complications and was evaluated histologically. Twenty two of 34 sites between the remnant fibula and β-TCP had achieved good bone regeneration. Five of 14 sites between the periosteum and β-TCP had achieved good bone regeneration. We found immature but evident bone formation in three cases with no osseous and periosteal sites. Histological analysis revealed bone formation on the outer macropore surface of β-TCP. Some blood vessels formed in the macropores expressed CD31 and CD34, while a few lymphatic vessels expressed CD34 and podoplanin. Thus, the osteoinductive ability of β-TCP alone was demonstrated in humans radiographically for the first time. The histological morphology of β-TCP was demonstrated at an early stage after grafting in humans. 展开更多
关键词 OSTEOINDUCTION OSTEOCONDUCTION Beta-Tricalcium Phosphate Bioactive
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RIS辅助认知反向散射通信网络吞吐量最大化算法
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作者 徐勇军 田秦语 +2 位作者 陈前斌 王公仆 杨刚 《中国科学:信息科学》 CSCD 北大核心 2024年第8期1970-1982,共13页
为了提高频谱利用率与解决反向散射通信存在障碍物阻挡导致通信质量急剧下降的问题,基于实际非线性能量收集模型,本文研究了智能超表面(reconfigurable intelligent surface,RIS)辅助的认知反向散射通信网络吞吐量最大化问题.考虑最大... 为了提高频谱利用率与解决反向散射通信存在障碍物阻挡导致通信质量急剧下降的问题,基于实际非线性能量收集模型,本文研究了智能超表面(reconfigurable intelligent surface,RIS)辅助的认知反向散射通信网络吞吐量最大化问题.考虑最大干扰功率、最小能量收集与RIS相移约束,建立了一个联合优化传输时间、发射功率、反射系数与RIS相移的多变量耦合资源分配模型。利用变量替换、二次变换和半正定松弛方法,将原问题转换为凸优化问题求解,并提出一种基于迭代的吞吐量最大化资源分配算法.仿真结果表明,与传统线性能量收集算法相比,所提算法平均吞吐量提升了15.0%;与传统无RIS辅助算法相比,所提算法平均吞吐量提升了22.7%. 展开更多
关键词 智能超表面 认知无线电 反向散射通信 吞吐量最大化 非线性能量收集
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Robust resource allocation for NOMA-assisted heterogeneous networks
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作者 Hao Xie yongjun xu 《Digital Communications and Networks》 SCIE CSCD 2022年第2期208-214,共7页
As a promising technology to improve spectrum efficiency and transmission coverage,Heterogeneous Network(HetNet)has attracted the attention of many scholars in recent years.Additionally,with the introduction of the No... As a promising technology to improve spectrum efficiency and transmission coverage,Heterogeneous Network(HetNet)has attracted the attention of many scholars in recent years.Additionally,with the introduction of the Non-Orthogonal Multiple Access(NOMA)technology,the NOMA-assisted HetNet cannot only improve the system capacity but also allow more users to utilize the same frequency band resource,which makes the NOMA-assisted HetNet a hot topic.However,traditional resource allocation schemes assume that base stations can exactly estimate direct link gains and cross-tier link gains,which is impractical for practical HetNets due to the impact of channel delays and random perturbation.To further improve energy utilization and system robustness,in this paper,we investigate a robust resource allocation problem to maximize the total Energy Efficiency(EE)of Small-Cell Users(SCUs)in NOMA-assisted HetNets under imperfect channel state information.By considering bounded channel uncertainties,the robust resource optimization problem is formulated as a mixed-integer and nonlinear programming problem under the constraints of the cross-tier interference power of macrocell users,the maximum transmit power of small base station,the Resource Block(RB)assignment,and the quality of service requirement of each SCU.The original problem is converted into an equivalent convex optimization problem by using Dinkelbach's method and the successive convex approximation method.A robust Dinkelbach-based iteration algorithm is designed by jointly optimizing the transmit power and the RB allocation.Simulation results verify that the proposed algorithm has better EE and robustness than the existing algorithms. 展开更多
关键词 Heterogeneous network Imperfect channel state information Non-orthogonal multiple access Robust resource allocation Energy efficiency maximization
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Passive Loss Inference in Wireless Sensor Networks Using EM Algorithm
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作者 Yu Yang Zhulin An +2 位作者 yongjun xu Xiaowei Li Canfeng Che 《Wireless Sensor Network》 2010年第7期512-519,共8页
Wireless Sensor Networks (WSNs) are mainly deployed for data acquisition, thus, the network performance can be passively measured by exploiting whether application data from various sensor nodes reach the sink. In thi... Wireless Sensor Networks (WSNs) are mainly deployed for data acquisition, thus, the network performance can be passively measured by exploiting whether application data from various sensor nodes reach the sink. In this paper, therefore, we take into account the unique data aggregation communication paradigm of WSNs and model the problem of link loss rates inference as a Maximum-Likelihood Estimation problem. And we propose an inference algorithm based on the standard Expectation-Maximization (EM) techniques. Our algorithm is applicable not only to periodic data collection scenarios but to event detection scenarios. Finally, we validate the algorithm through simulations and it exhibits good performance and scalability. 展开更多
关键词 Wireless Sensor Networks PASSIVE Measurement Network TOMOGRAPHY Data AGGREGATION EM Algorithm
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In-Plane Elastic Stability of Arches under a Radial Concentrated Load
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作者 yongjun xu Xiaoming Gui +1 位作者 Bin Zhao Ruiqi Zhou 《Engineering(科研)》 2014年第9期572-583,共12页
This paper is concerned with the in-plane elastic stability of arches subjected to a radial concentrated load. The equilibrium equation for pin-ended circular arches is established by using energy method, and it is pr... This paper is concerned with the in-plane elastic stability of arches subjected to a radial concentrated load. The equilibrium equation for pin-ended circular arches is established by using energy method, and it is proved that the axial force is nearly a constant along the circumference of the circular arches. Based on force method, the equation for the primary eigen function is derived and solved, and the approximate analytical solution of critical instability load is obtained. Numerical examples are given and discussed. 展开更多
关键词 IN-PLANE ELASTIC Stability BUCKLING Critical Load Circular ARCH Force Method
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Experimental and Numerical Study of the Effect of Surround Protection Technique on the Strain Measurement for Offshore Jacket Platform
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作者 yongjun xu 《Engineering(科研)》 2011年第5期485-490,共6页
For strain measurement on offshore jacket platform in deep water, waterproof of strain foil is always an important issue, especially, due to the high pressure in deep water. The waterproof is difficult in two places, ... For strain measurement on offshore jacket platform in deep water, waterproof of strain foil is always an important issue, especially, due to the high pressure in deep water. The waterproof is difficult in two places, one is between the matrix structure and the protection structure, and another is between the lead wires and the protection structure. The surround protection technique discussed in this paper is conventional and ideal, and can be operative for a long time, up to five years. In this method, a metal case and tube is added on the local position, which increases the local rigidity, but the effect on the measurement of strain is not well studied. In this paper, the effect of the surround protection technique on the strain measurement is studied by using numerical and experimental methods, and the results show that the measurement error is well in the range permitted by engineering practice. 展开更多
关键词 OFFSHORE JACKET Platform STRAIN Measurement STRAIN Foil SURROUND Protect/Waterproof TECHNIQUE
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非完美CSI条件下IRS辅助的NOMA系统安全速率最大化算法
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作者 王正强 何鲁娜 +3 位作者 樊自甫 万晓榆 徐勇军 多滨 《中国科学:信息科学》 CSCD 北大核心 2024年第6期1487-1501,共15页
本文针对智能反射面(intelligent reflecting surface,IRS)辅助的非正交多址接入系统的物理层安全问题,考虑窃听信道为非完美信道状态信息,基站在IRS的辅助下给合法用户传输数据.在基站最大发射功率、IRS相移和连续干扰消除解码顺序约束... 本文针对智能反射面(intelligent reflecting surface,IRS)辅助的非正交多址接入系统的物理层安全问题,考虑窃听信道为非完美信道状态信息,基站在IRS的辅助下给合法用户传输数据.在基站最大发射功率、IRS相移和连续干扰消除解码顺序约束下,建立了一个联合优化基站波束形成向量、IRS相移的系统安全速率最大化问题.首先,基于合法用户的组合信道增益来确定连续干扰消除解码顺序,然后将优化问题解耦为两个子问题交替优化,利用基于惩罚的连续凸逼近、松弛变量、一阶泰勒展开等方法将目标函数和约束进行转化,再利用S-procedure方法处理窃听信道的不确定性,将子问题转化为凸优化问题并求解.仿真结果表明,本文所提方案与集中部署IRS、随机相移、无IRS方案对比,能够有效提高系统的安全速率. 展开更多
关键词 智能反射面 非正交多址接入 物理层安全 非完美信道状态信息 波束成形
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A survey on causal inference for recommendation 被引量:1
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作者 Huishi Luo Fuzhen Zhuang +4 位作者 Ruobing Xie Hengshu Zhu Deqing Wang Zhulin An yongjun xu 《The Innovation》 EI 2024年第2期130-144,共15页
Causal inference has recently garnered significant interest among recommender system(RS)researchers due to its ability to dissect cause-and-effect relationships and its broad applicability across multiple fields.It of... Causal inference has recently garnered significant interest among recommender system(RS)researchers due to its ability to dissect cause-and-effect relationships and its broad applicability across multiple fields.It offers a framework to model the causality in RSs such as confounding effects and deal with counterfactual problems such as offline policy evaluation and data augmentation.Although there are already some valuable surveys on causal recommendations,they typically classify approaches based on the practical issues faced in RS,a classification that may disperse and fragment the uni-fied causal theories.Considering RS researchers’unfamiliarity with causality,it is necessary yet challenging to comprehensively review relevant studies from a coherent causal theoretical perspective,thereby facilitating a deeper integration of causal inference in RS.This survey provides a systematic review of up-to-date papers in this area from a causal theory standpoint and traces the evolutionary development of RS methods within the same causal strategy.First,we introduce the fundamental concepts of causal inference as the basis of the following review.Subsequently,we propose a novel theory-driven taxonomy,categorizing existing methods based on the causal theory employed,namely those based on the potential outcome framework,the structural causal model,and general counterfactuals.The review then delves into the technical details of how existing methods apply causal inference to address particular recommender issues.Finally,we highlight some promising directions for future research in this field.Representative papers and open-source resources will be progressively available at https://github.com/Chrissie-Law/Causal-Inference-forRecommendation. 展开更多
关键词 SURVEY DETAILS CAUSAL
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Artificial intelligence is restructuring a new world
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作者 yongjun xu Fei Wang Tangtang Zhang 《The Innovation》 EI 2024年第6期5-6,共2页
Recently,the 2024 Nobel Prizes in Physics and Chemistry were awarded to artificial intelligence(AI)scientists for their groundbreaking contributions.John J.Hopfield and Geoffrey E.Hinton received the Physics Prize for... Recently,the 2024 Nobel Prizes in Physics and Chemistry were awarded to artificial intelligence(AI)scientists for their groundbreaking contributions.John J.Hopfield and Geoffrey E.Hinton received the Physics Prize for their foundational discoveries and inventions that enabled machine learning through artificial neural networks.David Baker was awarded the Chemistry Prize for his work in computational protein design,while Demis Hassabis and John M.Jumper were recognized for their work in protein structure prediction. 展开更多
关键词 prediction. artificial BREAKING
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Artificial intelligence for science-bridging data to wisdom 被引量:2
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作者 yongjun xu Fei Wang +2 位作者 Zhulin An Qi Wang Zhao Zhang 《The Innovation》 EI 2023年第6期21-22,共2页
INTRODUCTION.Throughout the scientific discoveries of human history,research paradigms have undergone profound changes.'As shown in Figure 1,from the empirical paradigm,which relies on experimental observation,to ... INTRODUCTION.Throughout the scientific discoveries of human history,research paradigms have undergone profound changes.'As shown in Figure 1,from the empirical paradigm,which relies on experimental observation,to the theoretical paradigm,which is based on theoretical deduction,and further to the computational para-digm,which is associated with simulation and emulation,and finally to the data-driven paradigm,which is grounded in human-machine object integration,every transformation of scientific paradigm has brought about a major leap in science and technology. 展开更多
关键词 technology. FIGURE BRIDGING
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Deep Learning for Secure Transmission in Reconfigurable Intelligent Surface-Assisted Communications
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作者 Junhao Fang Xiangyu Zou +5 位作者 Chongwen Huang Zhaohui Yang yongjun xu Xiao Chen Jianfeng Shi Mohammad Shikh-Bahaei 《Journal of Communications and Information Networks》 EI CSCD 2023年第2期122-132,共11页
This paper investigates the secure transmission for reconfigurable intelligent surface(RIS)-assisted wireless communication systems.In the studied model,one user connects to the access point via a RIS while an eavesdr... This paper investigates the secure transmission for reconfigurable intelligent surface(RIS)-assisted wireless communication systems.In the studied model,one user connects to the access point via a RIS while an eavesdropper eavesdrops on the signal sent from the user to the access point.Therefore,it is necessary to design an appropriate RIS reflection vector to solve the eavesdropping problem.This problem is formulated as an optimization problem whose goal is to maximize the secure energy efficiency which is defined as the ratio of the secure rate to the total energy consumption of the system via jointly optimizing the RIS reflection reflector as well as the number of RIS elements,which results in a non-convex optimization problem that is intractable to solve by traditional methods.To tackle this issue,a new algorithm by leveraging the advance of the established deep learning(DL)technique is proposed so as to find the optimal RIS reflection vector and determine the optimal number of RIS reflection elements.Simulation results show that the proposed method reaches 96%of the optimal secure energy efficiency of the genie-aided algorithm. 展开更多
关键词 RISs physical layer security DL secure energy efficiency
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How to prevent malicious use of intelligent unmanned swarms?
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作者 Qi Wang Tingting Li +4 位作者 yongjun xu Fei Wang Boyu Diao Lei Zheng Jincai Huang 《The Innovation》 EI 2023年第2期37-39,共3页
With advancements in swarm intelligence,artificial intelligence,and wireless mobile network technology,unmanned swarms such as unmanned aerial vehicles,ground vehicles,ships,and other unmanned systems are becoming inc... With advancements in swarm intelligence,artificial intelligence,and wireless mobile network technology,unmanned swarms such as unmanned aerial vehicles,ground vehicles,ships,and other unmanned systems are becoming increasingly autonomous and intelligent.Benefiting from these technologies,intelligent unmanned swarms are able to efficiently perform complex tasks through collaboration in various fields.However,malicious use of intelligent unmanned swarms raises concerns about the potential for significant damage to national infrastructures such as airports and power facilities.Defending against malicious activities is essential but challenging due to the swarms’abilities to perceive,understand complex environments. 展开更多
关键词 AUTONOMOUS complex INTELLIGENT
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基于数能同传的D2D网络鲁棒资源分配算法 被引量:1
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作者 徐勇军 杨蒙 +1 位作者 周继华 陈前斌 《中国科学:信息科学》 CSCD 北大核心 2022年第10期1883-1899,共17页
为了提高终端直通(device-to-device,D2D)网络设备运行寿命和复杂电磁环境下的抗干扰能力,提出了一种基于数能同传的D2D网络系统能效最大化的鲁棒资源分配算法.考虑用户最小速率约束、最小收集能量约束、功率分流和信道分配因子约束,建... 为了提高终端直通(device-to-device,D2D)网络设备运行寿命和复杂电磁环境下的抗干扰能力,提出了一种基于数能同传的D2D网络系统能效最大化的鲁棒资源分配算法.考虑用户最小速率约束、最小收集能量约束、功率分流和信道分配因子约束,建立了联合优化传输功率、子信道和功率分流因子的鲁棒能效资源分配模型.基于Dinkelbach方法和Worst-case方法,将原NP-hard问题转换为确定性的凸优化问题,利用匹配理论和拉格朗日对偶理论获得解析解.仿真结果表明所提算法具有较好的鲁棒性和较高的能效. 展开更多
关键词 D2D通信 无线信息与功率同传技术 匹配理论 能效 鲁棒资源分配
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Double transition metal atoms anchored on Graphdiyne as promising catalyst for electrochemical nitrogen reduction reaction 被引量:5
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作者 Lakshitha Jasin Arachchige yongjun xu +3 位作者 Zhongxu Dai Xiao Li Zhang Feng Wang Chenghua Sun 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2021年第18期244-251,共8页
Ammonia synthesis by electrochemical nitrogen reduction technique is an attractive alternative to traditional Haber-Bosch process.Currently,development of an efficient and effective electrocatalyst is one of the remai... Ammonia synthesis by electrochemical nitrogen reduction technique is an attractive alternative to traditional Haber-Bosch process.Currently,development of an efficient and effective electrocatalyst is one of the remaining key challenges.In this work,density functional theory(DFT)computations were systematically employed on double transition metal atoms(Fe,Co,Ni,Cu and Mo)anchored Graphdiyne(GDY)for nitrogen reduction reaction(NRR).The Co-Ni heteronuclear complex and Mo-Mo homonuclear complex showed the highest NRR activity while demonstrating synergistic effect of double atomic catalytic sites towards the promising NRR activity. 展开更多
关键词 Double atom catalyst Graphdiyne NRR First-principles calculation
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