检索结果-南通市图书馆

Digital Communications and Networks 2024年第1期10卷 53-62页

作者： Zhipeng Cheng Minghui liwang ning Chen Lianfen Huang Nadra Guizani Xiaojiang Du Department of Information and Communication Engineering Xiamen UniversityXiamen361005China School of Electrical and Computer Engineering University of Texas at ArlingtonArlingtonTX76019USA Department of Electrical and Computer Engineering Stevens Institute of TechnologyHobokenNJ07030USA

Unmanned Aerial Vehicles(UAvs)as aerial base stations to provide communication services for ground users is a flexible and cost-effective paradigm in ***,dynamic resource allocation and multi-connectivity can be adopted to further harness the potentials of UAVs in improving communication capacity,in such situations such that the interference among users becomes a pivotal disincentive requiring effective *** this end,we investigate the Joint UAV-User Association,Channel Allocation,and transmission Power Control(J-UACAPC)problem in a multi-connectivity-enabled UAV network with constrained backhaul links,where each UAV can determine the reusable channels and transmission power to serve the selected ground *** goal was to mitigate co-channel interference while maximizing long-term system *** problem was modeled as a cooperative stochastic game with hybrid discrete-continuous action space.A Multi-Agent Hybrid Deep Reinforcement Learning(MAHDRL)algorithm was proposed to address this *** simulation results demonstrated the effectiveness of the proposed algorithm and showed that it has a higher system utility than the baseline methods.

关键词： UAV-user association Multi-connectivity Resource allocation Power control Multi-agent deep reinforcement learning

Current Research of Chlamydial Infection Diseases in China

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Medical Journal 2018年第4期131卷 486-489页

作者： Xue Li Qing-Feng Liang Guan-Yu Su Li-Yuan Wu Xin-Xin Lu ning-liwang Department of Laboratory Medicine Beijing Tongren Hospital Capital Medical University Beijing 100730 China Beijing Institute of Ophthalmology Beijing Tongren Eye Center Beijing Tongren Hospital Capital Medical University Beijing Key Laboratory of Ophthalmology and Visual Sciences Beijing 100005 China

To the Editor： Cblam.~zti^t organisms belong to intracellular bacterial pathogens which are responsible for a range of human diseases, including trachoma, sexually transmitted disease, pneumonia, and other diseases. Some Chlamydia-infected diseases were old and had long time impacted on the people＇s health in China and worldwide, but people cannot put enough emphasis on it in local areas.

关键词： COMMUNITY-ACQUIRED PNEUMONIA SEXUALLY-TRANSMITTED INFECTIONS TRACHOMA PREVALENCE MYCOPLASMA-PNEUMONIAE RURAL-AREAS CONJUNCTIVITIS CHILDREN WOMEN RISK EVOLUTION

Effect of intermittent joint distribution on the mechanical and acoustic behavior of rock masses

在线全文

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2024年第4期16卷 1231-1244页

作者： Shuaiyang Fu Haibo Li liwang Liu Di Wu Ben Wang State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China

The mechanical characteristics and acoustic behavior of rock masses are greatly influenced by stochastic *** this study,numerical models of rock masses incorporating intermittent joints with different numbers and dip angles were produced using the finite element method(FEM)with the intrinsic cohesive zone model(ICZM).Then,the uniaxial compressive and wave propagation simulations were *** results indicate that the joint number and dip angle can affect the mechanical and acoustic properties of the *** uniaxial compressive strength(UCS)and wave velocity of rock masses decrease monotonically as the joint number ***,the wave velocity grows monotonically as the joint dip angle *** the joint dip angle is 45°–60°,the UCS of the rock mass is lower than that of other dip *** wave velocity parallel to the joints is greater than that perpendicular to the *** the dip angle of joints remains unchanged,the UCS and wave velocity are positively *** the joint dip angle increases,the variation amplitude of the UCS regarding the wave velocity *** reveal the effect of the joint distribution on the velocity,a theoretical model was also *** to the theoretical wave velocity,the change in wave velocity of models with various joint numbers and dip angles was consistent with the simulation ***,a theoretical indicator(*** tensor)was adopted to analyze the variation of the wave velocity and UCS.

关键词： Stochastic joints Intrinsic cohesive zone model Uniaxial compressive strength(UCS) Wave propagation Fabric tensor

Time trends and disparities of obesity and related national policies and programs in Nepal:a systematic review

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Global Health Journal 2024年第2期8卷 46-57页

作者： Junxiang Wei Peng Nie liwang Gao Yang Mi Youfa Wang Department of Obstetrics Northwest Women's and Children's HospitalXi'anShaanxiChina School of Economics and Finance Xi'an Jiaotong UniversityXi'anShaanxiChina Center for Non-Communicable Disease Management Beijing Children's HospitalCapital Medical UniversityNational Center for Children's HealthBeijingChina Global Health Institute No.21 Hongren BuildingWest China Science and Technology lnnovation Harbour(iHarbour)Xi'anShaanxiChina School of Public Health Xi'an Jiaotong UniversityXi'anShaanxiChina

Objective Overweight and obesity prevalence has increased in low-income *** study systematically reviewed the obesity trend,disparities,and prevention and control efforts in *** We searched PubMed and Google Scholar for articles and reports published between January 1,2004 and December 31,*** information on National policies and programs related to obesity prevention was retrieved from governmental websites and consultation with relevant *** and obesity were defined using the World Health Organization body mass index cut ***-two studies and reports were *** Overall,overweight and obesity rates increased in all groups in Nepal although nationally representative data remained *** combined overweight and obesity(OW/OB)and obesity rates in women aged 15-49 years increased from 8.5%to 22.2%and from 0.9%to 5.1%between 2006 and 2016,***/OB and obesity rates in men were 17.1%and 2.5%based on data from the 2016 Demographic and Health ***/OB rate in under-five children increased from 0.6%to 2.8%between 2006 and *** rates for school-age(5-9 years)boys and girls in 2016 were 2.4%and 2.8%,respectively,and were 1.1%and 1.4%for male and female adolescents aged 10-19 years,***/OB prevalence was much higher among women,residents in urban areas and central provinces,and in higher socioeconomic status *** prevalence of OW/OB and obesity for 2030 in adults aged 15-49 was 44.7%and 8.3%,respectively,while it was 2.2%for OW/OB in preschool *** and direct interventions that specifically focused on obesity prevention and control are *** OW/OB prevalence in Nepal has increased during the past 1.8 decades,disproportionately affecting population *** interventions mostly focused on undernutrition with some indirect implications for obesity *** the future,Nepal needs to develop population-based programs for obesity

关键词： Nutrition transition Overweight Obesity Obesity prevention Systematic review Nepal

Reproducibility of Perfusion Parameters of Optic Disc and Macula in Rhesus Monkeys by Optical Coherence Tomography Angiography

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Medical Journal 2016年第9期129卷 1087-1090页

作者： Jing Li Yi-Quan Yang Di-Ya Yang Xiang-Xiang Liu Yun-Xiao Sun Shi-Fei Wei ning-liwang Beijing Tongren Eye Center Beijing Tongren Hospital Capital Medical University Beijing Ophthalmology and Visual Sciences Key Laboratory Beijing 100730 China Beijing Institute of Ophthalmology Beijing Tongren Hospitai Capital Medical University Beijing 100005 China

Background： Optical coherence tomography （OCT） angiography is a novel technique by which we can detect the local perfusion of fundus directly. The aim of this study was to evaluate the reproducibility of optic disc and macular flow perfusion parameters in rhesus monkeys using OCT angiography. Methods： Eighteen healthy monkeys （18 eyes） were subjected to optic disc and macula flow index measurements via a high-speed and high-resolution spectral-domain OCT XR Avanti with a split-spectrum amplitude de-correlation angiography algorithm. Right eye was imaged 3 times during the first examination and once during each of the two following examinations. The intra-visit and inter-visit intraclass correlation coefficients （ICCs） were both determined. Results： The average flow indices of the four optic disc area layers were 0.171 ± 0.009 （optic nerve head）, 0.015 ± 0.004 （vitreous）, 0.052 ±0.009 （radial peripapillary capillary）, and 0.167 ± 0.011 （choroid）. Average flow indices of the four macula area layers were 0,044 ± 0.011 （superficial retina）, 0.036 ± 0.011 （deep retina）, 0.016 ± 0.009 （outer retina）, and 0.155 ± 0.013 （choroid）. Intra-visit （1CC value： 0.821-0.954） and inter-visit （ICC value： 0.844±0.899） repeatability were both high. Conclusions： The study is about the reproducibility of optic disc and macular perfusion parameters as measured by OCT angiography in healthy rhesus monkeys. Flow index measurement reproducibility is high for both the optic disc and macula of normal monkey eyes. OCT angiography might be a useful technique to assess changes when examining monkeys with experimental ocular diseases.

关键词： Flow Index Macula Optic Disc Optical Coherence Tomography Angiography

Autonomous Recommendation of Fault Detection Algorithms for Spacecraft

在线全文

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2024年第1期11卷 273-275页

作者： Wenbo Li Baoling ning the National Key Laboratory of Science and Technology on Space Intelligent Control Beijing Institute of Control EngineeringBeijing 100094China the School of Data Science and Technology Heilongjiang UniversityHarbin 150001China

Dear Editor, This letter deals with the problem of algorithm recommendation for online fault detection of spacecraft. By transforming the time series data into distributions and introducing a distribution-aware measure, a principal method is designed for quantifying the detectabilities of fault detection algorithms over special datasets.

关键词： fault introducing letter

Performance enhancement of perovskite solar cells:surface is the key

在线全文

学校读者我要写书评

暂无评论

Science China Materials 2024年第1期67卷 375-376页

作者： Wenzhuo Li Zhijun ning School of Physical Science and Technology Shanghaitech UniversityShanghai 201210China

Metal halide perovskite solar cells(PSCs)stand out as one of the most promising contenders among photovoltaic technologies for the *** the past decade,PSCs with high power conversion efficiency(PCE)predominantly adopted the normal(ni-p)device ***,a common p-type organic small molecule,Spiro-OMe TAD,which is widely employed at the top layer of n-i-p devices[1],faces issues such as susceptibility to water absorption and poor thermal stability.

关键词： structure stability perovskite

Impact of non-ideal UE hardware on cell-free massive MIMO network with centralized operation

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2024年第4期67卷 255-271页

作者： ning LI Pingzhi FAN Institute of Mobile Communications Southwest Jiaotong University

This paper investigates the impact of non-ideal user equipment(UE) hardware on a cell-free(CF) massive MIMO(mMIMO) network with centralized operation under spatially correlated channels. The minimum mean-squared error(MMSE) estimator can be derived with the help of the generic non-ideal UE hardware model. It is demonstrated that even if the effective signal-to-noise ratio approaches infinity, pilot contamination and imperfect hardware can cause a non-zero estimation error floor. After that, a lower bound is determined for the ergodic uplink capacity of the centralized CF mMIMO network under non-ideal UE hardware. Moreover, the optimal receive combining vector is obtained to maximize the uplink spectral efficiency(SE). The maximum ratio(MR) and regularized zero-forcing(RZF) combining schemes are offered as alternatives in light of the computational complexity of the MMSE receiver. Comparing the RZF to the MMSE scheme under different levels of hardware impairments, our findings indicate that the RZF receiver suffers a negligible loss in total SE. For MR combining, a novel closed-form uplink achievable SE expression is obtained based on the MMSE estimator and the use-and-then-forget bounding technique. This expression gives vital insights into the achievable uplink performance with UE hardware impairments. Besides, for various hardware impairment factors, the impact of pilot sequence length on average sum SE is disclosed for different receive combining schemes. To increase the overall SE of the max-min fairness scheme, a heuristic fractional power control scheme with UE hardware impairments is developed, which can essentially avoid sacrificing the SE of other UEs while maximizing the SE of the unluckiest UE in the whole network. Finally,our theoretical performance analysis and power control algorithm are validated by simulation results, and fundamental design guidelines are provided for selecting hardware satisfying the practical UE requirements.

关键词： cell-free massive MIMO centralized operation spatially correlated channels hardware impairments channel estimation uplink spectral efficiency optimal receive combining pilot length design fractional power control

Imprints of ultralight axions on the gravitational wave and pulsar timing measurement

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2024年第1期67卷 23-29页

作者： ning Xie Fa Peng Huang MOE Key Laboratory of TianQin Mission TianQin Research Center for Gravitational Physics&School of Physics and AstronomyFrontiers Science Center for TianQinGravitational Wave Research Center of CNSASun Yat-sen University(Zhuhai Campus)Zhuhai 519082China

The axion or axion-like particle motivated from a natural solution of strong CP problem or string theory is a promising dark matter *** study the new observational effects of ultralight axion-like particles by the space-borne gravitational wave detector and the radio *** the neutron star-black hole binary as an example,we demonstrate that the gravitational waveform could be obviously modified by the slow depletion of the axion cloud around the black hole formed through the superradiance *** compare these new effects on the binary with the well-studied effects from dynamical friction with dark matter and dipole radiation in model-independent ***,we discuss the constraints from LIGO/Virgo and study the detectability of the ultralight axion particles at LISA and TianQin.

关键词： gravitational wave axion dark matter

Flocking Effects of the Stochastic Cucker-Smale System with Noise

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2024年第5期37卷 1978-1994页

作者： HAN ning GE Bin LI Lin School of Mathematical Sciences Harbin Engineering University

In this paper, the flocking behavior of a Cucker-Smale model with a leader and noise is studied in a finite time. The authors present a Cucker-Smale system with two nonlinear controls for a complex network with stochastic synchronization in probability. Based on the finite-time stability theory of stochastic differential equations, the sufficient conditions for the flocking of stochastic systems in a finite time are obtained by using the Lyapunov function method. Finally, the numerical simulation of the particle system is carried out for the leader and noise, and the correctness of the results is verified.

关键词： Cucker-Smale model flocking behavior leader noise