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Benefits Analysis of Beam Hopping in Satellite Mobile System with Unevenly Distributed Traffic 被引量:4
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作者 Yitao Li Zhongqiang Luo +1 位作者 Wuyang Zhou Jinkang Zhu 《China Communications》 SCIE CSCD 2021年第9期11-23,共13页
Satellite mobile system and space-airground integrated network have a prominent superiority in global coverage which plays a critical role in remote and non-land regions, as well as emergency communications. However, ... Satellite mobile system and space-airground integrated network have a prominent superiority in global coverage which plays a critical role in remote and non-land regions, as well as emergency communications. However, due to the gradual angle attenuations of the satellite antennas, it is difficult to achieve full frequency multiplex among different beams as terrestrial 5G network. Multi-color frequency reuse is widely adopted in both academic and industry. Beam hopping scheme has attracted the attention of researchers recently due to the allocation flexibility. In this paper, we focus on analyzing the performance benefits of beam hopping compared with multi-color frequency reuse scheme in non-uniform user and traffic distributions in satellite system. Aerial networks are also introduced to form a space-airground integrated network for coverage enhancement,and the capacity improvement is analyzed. Besides,additional improved techniques are provided to make comprehensive analysis and comparisons. Theoretical analysis and simulation results indicate that the beam hopping scheme has a prominent superiority in the system capacity compared with the traditional multicolor frequency reuse scheme in both satellite mobile system and future space-air-ground integrated network. 展开更多
关键词 satellite communication space-air-ground integrated network beam hopping unevenly distributed traffic performance analysis
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Microfluidic chips for the endothelial biomechanics and mechanobiology of the vascular system 被引量:3
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作者 HAORAN SU KEXIN LI +4 位作者 XIAO LIU JING DU LI WANG XIAOYAN DENG YUBO FAN 《BIOCELL》 SCIE 2021年第4期797-811,共15页
Endothelial cells arranged on the vessel lumen are constantly stimulated by blood flow,blood pressure and pressureinduced cyclic stretch.These stimuli are sensed through mechanical sensory structures and converted int... Endothelial cells arranged on the vessel lumen are constantly stimulated by blood flow,blood pressure and pressureinduced cyclic stretch.These stimuli are sensed through mechanical sensory structures and converted into a series of functional responses through mechanotransduction pathways.The process will eventually affect vascular health.Therefore,there has been an urgent need to establish in vitro endothelial biomechanics and mechanobiology of models,which reproduce three-dimensional structure vascular system.In recent years,the rapid development in microfluidic technology makes it possible to replicate the key structural and functionally biomechanical characteristics of vessels.Here,we summarized the progress of microfluidic chips used for the investigation of endothelial biomechanics and mechanobiology of the vascular system.Firstly,we elucidated the contribution of shear stress and circumferential stress,to vascular physiology.Then,we reviewed some applications using microfluidic technology in angiogenesis and vasculogenesis,endothelial permeability and mechanotransduction,as well as the blood-brain barrier under these physical forces.Finally,we discussed the future obstacles in terms of the development and application of microfluidic vascular chips. 展开更多
关键词 Endothelial cells Vascular system MECHANOTRANSDUCTION Microfluidic chip
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A photometric-spectroscopic study of the infrared-excess eclipsing binary V2364 Cyg
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作者 Hui-Yu Yuan Lin-Qiao Jiang +2 位作者 Hai-Feng Dai Shuang Wang Yuan-Gui Yang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2020年第12期307-316,共10页
The eclipsing binary V2364 Cyg is an A7 V-type contact binary with a period of 0.5921 d.We present six spectra from LAMOST and BVRc light curves(LCs),which are simultaneously analyzed to obtain the absolute physical p... The eclipsing binary V2364 Cyg is an A7 V-type contact binary with a period of 0.5921 d.We present six spectra from LAMOST and BVRc light curves(LCs),which are simultaneously analyzed to obtain the absolute physical parameters.The first light maxima are brighter than the second ones by up to 0.m038,0.m036 and 0.m024 for BVRc bands,respectively.These distorted LCs are modeled by a cool spot on the less massive component.Its mass ratio and over-contact degree are q=0.319(±0.004) and f=28.4%(±1.0) % respectively.From the mass-luminosity diagram,the primary component is a normal main-sequence star,while the secondary one is a subgiant star.From the(O-C) curve,the orbital period secularly decreases at a rate dP/dt=-1.62(±0.03) × 10^-7 dyr^-1,which is mainly attributed to mass loss via stellar wind from the binary system.This may result in the observed infrared excess in the W4 band. 展开更多
关键词 stars:circumstellar matter stars:binaries:close stars:individual(V2364 Cyg) mass loss infrared excess
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The first photometric investigation of the contact binary OQ Cam
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作者 Ya-Ni Guo Kai Li +3 位作者 Qi-Qi Xia Xing Gao Lin-Qiao Jiang Yuan Liu 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2020年第11期252-258,共7页
The first charge-coupled device photometric light curves in B,V,Rc,and Ic bands of the short-period contact binary star OQ Cam are presented.Through analyzing the light curves with the WilsonDevinney code,it is found ... The first charge-coupled device photometric light curves in B,V,Rc,and Ic bands of the short-period contact binary star OQ Cam are presented.Through analyzing the light curves with the WilsonDevinney code,it is found that OQ Cam is a W-type shallow contact binary star with a contact degree of f=20.2%.Based on the O-C analyzing,the orbit period displays a long term increasing with a rate of d P/dt=4.40×10^-7 d yr-1.The increasing in orbit period can be interpreted by mass transfer from the less massive component to the more massive one.As the orbit period increases,OQ Cam would evolve from the present shallow contact configuration to a non-contact stage.So it may be a potential candidate to confirm the thermal relaxation oscillation theory. 展开更多
关键词 STARS BINARIES CLOSE STARS BINARIES ECLIPSING STARS evolution STARS individual(OQ Cam)
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Some Chaotic Properties of a Kind of Coupled Map Lattices
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作者 Xiaofang Yang Tianxiu Lu Guo Liu 《Journal of Applied Mathematics and Physics》 2020年第6期968-975,共8页
This paper is concerned with some chaotic properties of a kind of coupled map lattices, which is proposed by Kaneko. First, this research discussed the sensitivity, infinite sensitivity, transitivity, accessibility, d... This paper is concerned with some chaotic properties of a kind of coupled map lattices, which is proposed by Kaneko. First, this research discussed the sensitivity, infinite sensitivity, transitivity, accessibility, densely Li-Yorke sensitivity and exact of coupled map lattices. Then, some sufficient conditions under which <img src="Edit_c0fc315a-d176-4c9e-9e41-5cb6bc6d679d.bmp" alt="" /> is Kato chaotic, positive entropy chaotic and Ruelle-Takens chaos are obtained. 展开更多
关键词 Coupled Map Lattices Sensitivity CHAOS ACCESSIBILITY
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Characterization of ultraviolet communication in a mixed aerosol environment
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作者 ZHAO Taifei SUN Yuxin +3 位作者 WANG Wuxin ZHANG Haijun PAN Feixiang WU Hao 《Optoelectronics Letters》 2025年第2期77-84,共8页
Wireless ultraviolet (UV) has strong scattering characteristics and can communicate through non-direct vision.When UV signals are transmitted in the atmosphere,they are affected by the absorption and scattering effect... Wireless ultraviolet (UV) has strong scattering characteristics and can communicate through non-direct vision.When UV signals are transmitted in the atmosphere,they are affected by the absorption and scattering effects of atmospheric particles and atmospheric turbulence,resulting in attenuation of UV signal energy and reduced reliability of the communication system.This paper focuses on the channel model of UV non-direct-view single scattering communication,and simulates and analyzes the communication characteristics of UV light in atmospheric turbulence and mixed aerosol environment under horizontal,vertical and oblique range communication scenarios.The results show that at equal relative humidity,the wireless UV non-directive scattering communication performance for vertical communication scenarios is more affected by the mixed aerosol environment and the communication performance is worse. 展开更多
关键词 COMMUNICATION SCATTERING ULTRAVIOLET
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Traveling Salesman Problem Using an Enhanced Hybrid Swarm Optimization Algorithm 被引量:2
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作者 郑建国 伍大清 周亮 《Journal of Donghua University(English Edition)》 EI CAS 2014年第3期362-367,共6页
The traveling salesman problem( TSP) is a well-known combinatorial optimization problem as well as an NP-complete problem. A dynamic multi-swarm particle swarm optimization and ant colony optimization( DMPSO-ACO) was ... The traveling salesman problem( TSP) is a well-known combinatorial optimization problem as well as an NP-complete problem. A dynamic multi-swarm particle swarm optimization and ant colony optimization( DMPSO-ACO) was presented for TSP.The DMPSO-ACO combined the exploration capabilities of the dynamic multi-swarm particle swarm optimizer( DMPSO) and the stochastic exploitation of the ant colony optimization( ACO) for solving the traveling salesman problem. In the proposed hybrid algorithm,firstly,the dynamic swarms,rapidity of the PSO was used to obtain a series of sub-optimal solutions through certain iterative times for adjusting the initial allocation of pheromone in ACO. Secondly,the positive feedback and high accuracy of the ACO were employed to solving whole problem. Finally,to verify the effectiveness and efficiency of the proposed hybrid algorithm,various scale benchmark problems were tested to demonstrate the potential of the proposed DMPSO-ACO algorithm. The results show that DMPSO-ACO is better in the search precision,convergence property and has strong ability to escape from the local sub-optima when compared with several other peer algorithms. 展开更多
关键词 particle SWARM optimization(PSO) ant COLONY optimization(ACO) SWARM intelligence TRAVELING SALESMAN problem(TSP) hybrid algorithm
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A Data Transmission Path Optimization Protocol for Heterogeneous Wireless Sensor Networks Based on Deep Reinforcement Learning 被引量:1
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作者 Yu Song Zhigui Liu Xiaoli He 《Journal of Computer and Communications》 2023年第8期165-180,共16页
Wireless sensor networks had become a hot research topic in Information science because of their ability to collect and process target information periodically in a harsh or remote environment. However, wireless senso... Wireless sensor networks had become a hot research topic in Information science because of their ability to collect and process target information periodically in a harsh or remote environment. However, wireless sensor networks were inherently limited in various software and hardware resources, especially the lack of energy resources, which is the biggest bottleneck restricting their further development. A large amount of research had been conducted to implement various optimization techniques for the problem of data transmission path selection in homogeneous wireless sensor networks. However, there is still great room for improvement in the optimization of data transmission path selection in heterogeneous wireless sensor networks (HWSNs). This paper proposes a data transmission path selection (HDQNs) protocol based on Deep reinforcement learning. In order to solve the energy consumption balance problem of heterogeneous nodes in the data transmission path selection process of HWSNs and shorten the communication distance from nodes to convergence, the protocol proposes a data collection algorithm based on Deep reinforcement learning DQN. The algorithm uses energy heterogeneous super nodes as AGent to take a series of actions against different states of HWSNs and obtain corresponding rewards to find the best data collection route. Simulation analysis shows that the HDQN protocol outperforms mainstream HWSN data transmission path selection protocols such as DEEC and SEP in key performance indicators such as overall energy efficiency, network lifetime, and system robustness. 展开更多
关键词 HWSNs Clusting Deep Reinforcement Learning DQN
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Independent Vector Analysis Based Blind Interference Reduction and Signal Recovery for MIMO IoT Green Communications
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作者 Zhongqiang Luo Mingchun Li Chengjie Li 《China Communications》 SCIE CSCD 2022年第7期79-88,共10页
In application to time convolutive mixing model or frequency domain blind separation model for wireless receiving applications,frequency domain independent component analysis(FDICA)has been a very popular method but w... In application to time convolutive mixing model or frequency domain blind separation model for wireless receiving applications,frequency domain independent component analysis(FDICA)has been a very popular method but with adverse random permutation ambiguity influence.In order to solve this inherent problem in FDICA assisted multiple-input multiple-output orthogonal frequency-division multiplexing(MIMO-OFDM)based the Internet of Thing(IoT)systems,this paper proposes an new detection mechanism,named independent vector analysis(IVA),for realizing blind adaptive signal recovery in MIMO IoT green communication to reduce inter-carrier interference(ICI)and multiple access interference(MAI).IVA jointly implements separation work for different frequency bin data while the FDICA deals with it separately.In IVA,the dependencies of frequency bins can be exploited in mitigating the random permutation problem.In addition,multivariate prior distributions are employed to preserve the inter-frequency dependencies for individual sources,which can result in separation performance enhancement.Simulation results and analysis corroborate the effectiveness of the proposed method. 展开更多
关键词 independent vector analysis blind source separation MIMO green communications
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Study on Synchronous Generator Excitation Control Based on FLC
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作者 Zhiting Guo Hong Song +1 位作者 Penggao Wen Zhizheng Fan 《World Journal of Engineering and Technology》 2015年第4期232-239,共8页
With the development of the national economy, the demand of electric power market has become higher than before. The stable and reliable power system is one of the important national economic securities. Reliability o... With the development of the national economy, the demand of electric power market has become higher than before. The stable and reliable power system is one of the important national economic securities. Reliability of generator excitation system is one of the important elements to determine the stability of the power system. Traditional PID cannot meet the requirements of the increasingly complex power system due to some defects. This essay introduces FLC control, combining with the traditional PID control. Using Matlab software, we analyze the curve and FLC is better than that by comparing with the traditional PID. 展开更多
关键词 Power System STABILITY EXCITATION CONTROL TRADITIONAL PID CONTROL FLC
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Path following of underactuated vehicles via integral line of sight guidance and fixed‐time heading control
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作者 Pengfei Zhang Qiyuan Chen Ping He 《IET Cyber-Systems and Robotics》 EI 2022年第1期51-60,共10页
This study investigates the integral line of sight(ILOS)path‐following control problem of surface vehicles whose dynamics feature external disturbances,model uncertainties,and actuator dead zones.First,introducing th... This study investigates the integral line of sight(ILOS)path‐following control problem of surface vehicles whose dynamics feature external disturbances,model uncertainties,and actuator dead zones.First,introducing the ILOS guidance law,the path‐following control problem is converted to stabilising a 2nd order nonlinear system.Subsequently,the fixed‐time observer is designed to estimate and compensate for the uncertainties and unknown external disturbances while overcoming the actuator dead zones.Finally,the trajectory tracking control strategy is designed based on the fixed‐time observer.Numerical ex-amples are given to illustrate the effectiveness of the proposed approaches. 展开更多
关键词 control dynamic model Unmanned Aerial Vehicle
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Correlation analysis between lung ultrasound scores and pulmonary arterial systolic pressure in patients with acute heart failure admitted to the emergency intensive care unit
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作者 Ping Xu Basma Nasr +3 位作者 Liang Li Wenbin Huang Wei Liu Xuelian Wang 《Journal of Intensive Medicine》 CSCD 2024年第1期125-132,共8页
Background:No convenient,inexpensive,and non-invasive screening tools exist to identify pulmonary hypertension(PH)-left heart disease(LHD)patients during the early stages of the disease course.This study investigated ... Background:No convenient,inexpensive,and non-invasive screening tools exist to identify pulmonary hypertension(PH)-left heart disease(LHD)patients during the early stages of the disease course.This study investigated whether different methods of lung ultrasound(LUS)could be used for the initial investigation of PH-LHD.Methods:This was a single-center prospective observational study which was performed in the Zigong Fourth People’s Hospital.We consecutively enrolled patients with heart failure(HF)admitted to the emergency intensive care unit from January 2018 to May 2020.Transthoracic echocardiography and LUS were performed within 24 h before discharge.We used the Spearman coefficient for correlation analysis between ultrasound scores and pulmonary arterial systolic pressure(PASP).Bland-Altman plots were generated to inspect possible bias,and receiver operating characteristic(ROC)curves were calculated to assess the relationship between ultrasound scores and an intermediate and high echocardiographic probability of PH-LHD.Results:Seventy-one patients were enrolled in this study,with an overall median age of 79(interquartile range:71.5–84.0)years.Among the 71 patients,36(50.7%)cases were male,and 26(36.6%)had an intermediate and high echocardiographic probability of PH.All four LUS scores in patients with an intermediate and high probability of PH were significantly higher than in patients with a low probability of PH(P<0.05).The correlation coefficient(r)between different LUS scoring methods and PASP was moderate for the 6-zone(r=0.455,P<0.001),8-zone(r=0.385,P=0.001),12-zone(r=0.587,P<0.001),and 28-zone(r=0.535,P<0.001)methods.In Bland-Altman plots,each of the four LUS scoring methods had a good agreement with PASP(P<0.001).The 8-zone and 12-zone methods showed moderately accurate discriminative values in differentiating patients with an intermediate and high echocardiographic probability of PH(P<0.05). 展开更多
关键词 Acute heart failure Pulmonary arterial systolic pressure Pulmonary hypertension Left heart disease Lung ultrasound
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Tolerance-based multigranulation rough sets in incomplete systems 被引量:5
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作者 Zaiyue ZHANG Xibei YANG 《Frontiers of Computer Science》 SCIE EI CSCD 2014年第5期753-762,共10页
Presently, the notion of multigranulation has been brought to our attention. In this paper, the multigranulation technique is introduced into incomplete information systems. Both tolerance relations and maximal consis... Presently, the notion of multigranulation has been brought to our attention. In this paper, the multigranulation technique is introduced into incomplete information systems. Both tolerance relations and maximal consistent blocks are used to construct multigranulation rough sets. Not only are the basic properties about these models studied, but also the relationships between different multigranulation rough sets are explored. It is shown that by using maximal consistent blocks, the greater lower approximation and the same upper approximation as from tolerance relations can be obtained. Such a result is consistent with that of a single-granulation framework. 展开更多
关键词 incomplete information system maximal con-sistent block multigranulation rough sets tolerance relation
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