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Improved PSO-Extreme Learning Machine Algorithm for Indoor Localization

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china Communications 2024年第5期21卷 113-122页

作者： Qiu Wanqing Zhang Qingmiao Zhao junhui yang Lihua School of Information Engineering East China Jiaotong UniversityNanchang 330013China School of Electronic and Information Engineering Beijing Jiaotong UniversityBeijing 100044China

Wi Fi and fingerprinting localization method have been a hot topic in indoor positioning because of their universality and location-related *** basic assumption of fingerprinting localization is that the received signal strength indication(RSSI)distance is accord with the location ***,how to efficiently match the current RSSI of the user with the RSSI in the fingerprint database is the key to achieve high-accuracy *** this paper,a particle swarm optimization-extreme learning machine(PSO-ELM)algorithm is proposed on the basis of the original fingerprinting ***,we collect the RSSI of the experimental area to construct the fingerprint database,and the ELM algorithm is applied to the online stages to determine the corresponding relation between the location of the terminal and the RSSI it ***,PSO algorithm is used to improve the bias and weight of ELM neural network,and the global optimal results are ***,extensive simulation results are *** is shown that the proposed algorithm can effectively reduce mean error of localization and improve positioning accuracy when compared with K-Nearest Neighbor(KNN),Kmeans and Back-propagation(BP)algorithms.

关键词： extreme learning machine fingerprinting localization indoor localization machine learning particle swarm optimization

Robotic compliant assembly for complex-shaped composite aircraft frame based on Gaussian process considering uncertainties

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chinese Journal of Aeronautics 2024年第10期37卷 471-482页

作者： Yingke yang Dongsheng LI Yunong zhai Jie WANG Lei XUE Zhiyong yang School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China Ningbo Institute of Technology Beihang UniversityNingbo 3158002China COMAC Shanghai Aircraft Manufacturing Co. Ltd.Shanghai 201324China

Robots are finding increasing application in aircraft composite structure assembly due to their flexibility and the growing demand of aircraft manufacturers for high production *** contact force of the composite frame in a robotic assembly of the aircraft composite fuselage panel can hardly be controlled due to the multi-surface variable contact stiffness caused by compliance and complex shape with multiple mating *** paper proposes a robotic assembly system for the aircraft composite fuselage frame with a compliant contact force control strategy using the Gaussian process surrogate ***,a robotic assembly system is introduced,and the global coordinate system transformation model is ***,a compliant force control architecture is designed to generate the desired output ***,a Gaussian process surrogate model with uncertainties is utilized to model the complicated relationship between the robot’s output force and the normal contact force acting on the mating surface of the composite ***,an optimal contact force control strategy is implemented to improve the contact ***,an experiment demonstrates that the proposed methodology can ensure that the contact force on each surface is within the limit of the engineering specification and uniformly distributed,improving the quality compared to the traditional assembly process.

关键词： Aircraft Composite structure assembly Multi-surface contact Compliant control Gaussian process Uncertainty

Extraordinary hot extreme in summer 2.2. over the yangtze River basin modulated by the La Nina condition under global warming

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Advances in Climate Change Research 2024年第1期15卷 21-30页

作者： Zhen LIAO Yu-Feng YUAN yang CHEN Pan-Mao zhai State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China

A widespread and prolonged hot extreme hit the yangtze River basin in summer 2.2.,with 300 sites established new temperature records and nearly 96%stations endured more than 40 hot *** the perspective of the combination effect of the global warming and La Nina condition,potential mechanisms of the hot extreme were *** a record-breaking hot extreme was caused by an extremely strong and westward-shifted western Pacific subtropical high(WPSH).The global warming effect contributed primarily to the abnormal hot days in the yangtze River basin,coupled with the modulation of the La Nina *** sea surface temperature anomaly pattern under La Nina condition favored more convection activities over the western Pacific,encouraging an enhanced and westward-extended *** addition,an observation-based attribution analysis indicates that anthropogenic warming may increase the probability of such extensively persistent hot extremeby1.8 times.

关键词： Hot extreme The yangtze River basin Global warming Tropical Pacific forcing

Airflow Analytical Toolkit(AAT):A MATLAB-based analyzer for holistic studies on the dynamic characteristics of airflows

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Building Simulation 2024年第7期17卷 1137-1159页

作者： Zuoyu Xie junhui Fan Bin Cao Yingxin Zhu Department of Building Science School of ArchitectureTsinghua UniversityBeijingChina Key Laboratory of Eco Planning&Green Building Ministry of Education(Tsinghua University)BeijingChina

The dynamic characteristics of different airflows on micro-scales have been explored from many perspectives since the late *** the one hand,most analytical tools and research subjects in previous contributions vary significantly:some only focus on fluctuant velocity features,while others pay attention to directional *** the other hand,despite the wide variety of existing analytical methods,they are not systematically classified and *** paper aims to establish a system including state-of-the-art tools for airflow analysis and to further design a holistic toolkit named Airflow Analytical Toolkit(AAT).The AAT contains two tools,responsible for analyzing the velocity and direction characteristics of airflows,each of which is integrated with multiple analytical *** assess the performance of the developed toolkit,we further take typical natural and mechanical winds as cases to show its excellent analytical *** the help of this toolkit,the great differences in velocity and directional characteristics among different airflows are *** comparative results reveal that not only is the velocity of natural wind more fluctuating than that of mechanical wind,but its incoming flow direction is also more *** AAT,serving as a powerful and user-friendly instrument,will hopefully offer great convenience in data analysis and guidance for a deeper understanding of the dynamic characteristics of airflows,and further remedy the gap in airflow analytical tools.

关键词： airflow analysis dynamic characteristic wind velocity wind direction thermal comfort wind comfort

A four-band index for both liquid and solid water and its applications in the Aral Sea Basin

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Science china Earth sciences 2024年第3期67卷 769-788页

作者： Bing YUE Xi CHEN Saibo LI Zhengping DU John WILSON junhui yang Yimen JIAO Shuangyan HUANG Chenghu ZHOU Xinjiang Institute of Ecology and Geography Chinese Academy of SciencesUrumqi 830011China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China Institute of Geographical sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China Spatial sciences Institute University of Southern CaliforniaLos AngelesCA 90089-0374USA

Various investigations have been conducted to analyze the water-coverage area of the Aral Sea and the Aral Sea Basin(ASB). However, the investigations incorporated considerable uncertainty and the used water indices had misclassification problem, which made different research groups present different results. Thus we first ascertain the boundaries of the ASB, the Syr and Amu river basins as well as their upper, middle and lower reaches. Then a four-band index for both liquid and solid water(ILSW) is proposed to address the misclassification problems of the classic water indices. ILSW is calculated by using the reflectance values of the green, red, near infrared, and thermal infrared bands, which combines the normalized difference water index(NDWI) and land surface temperature(LST) together. Validation results show that the ILSW water index has the highest accuracy by far in the Aral Sea Basin. Our results indicate that annual average decline of the water-coverage area was 963 km^(2. in the southern Aral Sea, whereas the northern Aral Sea has experienced little change. In the meanwhile, permanent ice and snow in upper reach of ASB has retreated considerably. Annual retreating rates of the permanent ice and snow were respectively 62.3and 3841 km^(2. in upper reaches of Amu river basin(UARB) and Syr river basin(USRB). One of major reasons is that climate has become warmer in ASB. The climate change has caused serious water deficit problem. The water deficit had an increasing trend since the 1990s and its increasing rates was 3.778 billion m^(3) yearly on average. The total water deficit was 76.967 billion m^(3) on average in the whole area of ASB in the 2.10s. However, up reaches of Syr river basin(USRB), a component area of ASB, had water surplus of 2..461 billion m^(3). These conclusions are useful for setting out a sustainable development strategy in ASB.

关键词： Aral Sea Basin Syr river basin Amu river basin Water indices Water-coverage area Water deficit Climate change

Energy Storage Operation Modes in Typical Electricity Market and Their Implications for china

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Energy Engineering 2024年第9期121卷 2409-2434页

作者： junhui Liu Yihan Zhang Zijian Meng Meng yang Yao Lu Zhe Chai Zhaoyuan Wu State Grid Henan Economic Research Institute Zhengzhou450052China School of Electrical and Electronic Engineering North China Electric Power UniversityBeijing102206China

As the chinese government proposes ambitious plans to promote low-carbon transition,energy storage will play a pivotal role in china’s future power ***,due to the lack of a mature electricity market environment and corresponding mechanisms,current energy storage in china faces problems such as unclear operational models,insufficient cost recovery mechanisms,and a single investment entity,making it difficult to support the rapid development of the energy storage *** contrast,European and American countries have already embarked on certain practices in energy storage operation *** exploration of key issues such as investment entities,market participation forms,and cost recovery channels in both front and back markets,a wealth of mature experiences has been ***,this paper first summarizes the existing practices of energy storage operation models in North America,Europe,and Australia’s electricity markets separately from front and back markets,finding that perfect market mechanisms and reasonable subsidy policies are among the main drivers for promoting the rapid development of energy storage ***,combined with the actual development of china’s electricity market,it explores three key issues affecting the construction of costsharing mechanisms for energy storage under market conditions:Market participation forms,investment and operation modes,and cost recovery ***,in line with the development expectations of china’s future electricitymarket,suggestions are proposed fromfour aspects:Market environment construction,electricity price formation mechanism,cost sharing path,and policy subsidy mechanism,to promote the healthy and rapid development of china’s energy storage industry.

关键词： Electricity market energy storage operational mode cost-sharing mechanism

Optimization of Center of Gravity Position and Anti-Wave Plate Angle of Amphibious Unmanned Vehicle Based on Orthogonal Experimental Method

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Computer Modeling in Engineering & sciences 2024年第5期139卷 2027-2041页

作者： Deyong Shang Xi Zhang Fengqi Liang Chunde zhai Hang yang Yanqi Niu School of Mechanical Electronic&Information EngineeringChina University of Mining and Technology(Beijing)Beijing100083China Institute of Intelligent Mining&Robotics China University of Mining and Technology(Beijing)Beijing100083China

When the amphibious vehicle navigates in water,the angle of the anti-wave plate and the position of the center of gravity greatly influence the navigation *** the relevant research on reducing the navigation resistance of amphibious vehicles by adjusting the angle of the anti-wave plate,there is a lack of scientific selection of parameters and reasonable research of simulation results by using mathematical methods,and the influence of the center of gravity position on navigation characteristics is not considered at the same *** study the influence of the combinations of the angle of the anti-wave plate and the position of the center of gravity on the resistance reduction characteristics,a numerical calculation model of the amphibious unmanned vehicle was established by using the theory of computational fluid dynamics,and the experimental data verified the correctness of the numerical *** on this numerical model,the navigation characteristics of the amphibious unmanned vehicle were studied when the center of gravity was located at different positions,and the orthogonal experimental design method was used to optimize the parameters of the angle of the anti-wave plate and the position of the center of *** results show that through the parameter optimization analysis based on the orthogonal experimental method,the combination of the optimal angle of the anti-wave plate and the position of the center of gravity is *** the numerical simulation result of resistance is consistent with the predicted optimal *** with the maximum navigational resistance,the parameter optimization reduces the navigational resistance of the amphibious unmanned vehicle by 2.%.

关键词： Amphibious unmanned vehicle orthogonal experimental design anti-wave plate center of gravity resistance characteristic

A columnar multi-layer sliding triboelectric nanogenerator for water wave energy harvesting independent of wave height and direction

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Nano Research 2024年第4期17卷 3029-3034页

作者： Xue Miao Hanxiao yang Zekun Li Meifei Cheng Yilin Zhao Lingyu Wan Aifang Yu Junyi zhai Center on NanoEnergy Research School of Physical Science and TechnologyGuangxi UniversityNanning 530004China beijing Institute of Nano Energy and Nano Systems Chinese Academy of SciencesBeijing 101400China School of Nanoscience and Engineering University of Chinese Academy of ScienceBeijing 101408China

The ocean,with its highly variable and complex meteorological conditions,harbors enormous renewable *** nanogenerators(TENGs),which possess unique advantages,show exciting prospects in water wave energy *** to design and optimize TENGs to cover all characteristic water wave energies and achieve efficient energy utilization is *** this paper,we carefully designed and fabricated a columnar multi-layer sliding TENG(CMLS-TENG)that can harvest water wave energy independent of wave height and *** rods with a hollow acrylic spherical shell were introduced to deliver wave energy,ensuring that the CMLS-TENG can work in all directions from 0°to 360°.Based on the sliding structure,switching the optimized CMLS-TENG is independent of wave *** optimized CMLS-TENG can achieve a total power density of 730 mW/m^(3) at a wave height of only 4.8 cm regardless of wave direction,which can illuminate multiple light-emitting diodes(LEDs)to provide lighting and provide power to a watch and a hygrometer for temperature and humidity *** work provides new choices and hopes for the effective collection of full-range water wave energy.

关键词： triboelectric nanogenerator wave energy multi-direction columnar slide

High performance receiving and processing technology in satellite beam hopping communication

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Journal of Systems Engineering and Electronics 2024年第4期35卷 815-828页

作者： zhai Shenghua HUI Tengfei GONG Xianfeng ZHANG Zehui GAO Xiaozheng yang Kai School of Communication Engineering Xi’Dian UniversityXian 710126China CAST(china Academy of Space Technology)-Xi’an Institute of Space Radio Technology Xi’an 710010China School of Cyberspace Science and Technology Beijing Institute of TechnologyBeijing 100081China School of Information and Electronics Beijing Institute of TechnologyBeijing 100081China

Beam-hopping technology has become one of the major research hotspots for satellite communication in order to enhance their communication capacity and ***,beam hopping causes the traditional continuous time-division multiplexing signal in the forward downlink to become a burst signal,satellite terminal receivers need to solve multiple key issues such as burst signal rapid synchronization and high-per-formance ***,this paper analyzes the key issues of burst communication for traffic signals in beam hopping sys-tems,and then compares and studies typical carrier synchro-nization algorithms for burst ***,combining the requirements of beam-hopping communication systems for effi-cient burst and low signal-to-noise ratio reception of downlink signals in forward links,a decoding assisted bidirectional vari-able parameter iterative carrier synchronization technique is pro-posed,which introduces the idea of iterative processing into car-rier *** at the technical characteristics of communication signal carrier synchronization,a new technical approach of bidirectional variable parameter iteration is adopted,breaking through the traditional understanding that loop struc-tures cannot adapt to low signal-to-noise ratio burst ***,combining the DVB-S2. standard physical layer frame format used in high throughput satellite communication systems,the research and performance simulation are *** results show that the new technology proposed in this paper can significantly shorten the carrier synchronization time of burst signals,achieve fast synchronization of low signal-to-noise ratio burst signals,and have the unique advantage of flexible and adjustable parameters.

关键词： beam-hopping high throughput satellite high per-formance reception processing