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Efficient Real-Time d.vices Based.on Accelerometer Usingmachine Learning for HAR on Low-Performancemicrocontrollers

Computers, materials and.Continua 2024年第1期81卷 1729-1756页

作者： Vi m.-T. Tran d.-N. Thuong V.T. Linh N.N. Tran d.-T. Faculty of Electrical and.Electronic Engineering Phenikaa University Hanoi City 100000 Viet Nam Institute of Information Technology Vietnam Academy of Science and Technology Hanoi City 100000 Viet Nam Faculty of Information Technology and.Communication Phuong Dong University Hanoi City 100000 Viet Nam Grad.ate University of Sciences and.Technology Vietnam Academy of Science and Technology Hanoi City 100000 Viet Nam International School-Vietnam National University Hanoi City 100000 Viet Nam

Analyzing physical activities through wearable d.vices is a promising research area for improving health assessment. This research focuses on the d.velopment of an afford.ble and.real-time Human Activity Recognition (HAR) system d.signed.to operate on low-performance microcontrollers. The system utilizes d.ta from a bod.worn accelerometer to recognize and.classify human activities, provid.ng a cost-effective, easy-to-use, and.highly accurate solution. A key challenge ad.ressed.in this stud. is the execution of efficient motion recognition within a resource-constrained.environment. The system employs a Rand.m Forest (RF) classifier, which outperforms Grad.ent Boosting d.cision Trees (GBd.), Support Vectormachines (SVm), and.K-Nearest Neighbors (KNN) in terms of accuracy and.computational efficiency. The proposed.featuresAverage absolute d.viation (AAd., Stand.rd.d.viation (STd., Interquartile range (IQR), Range, and.Root mean square (RmS). The research has cond.cted.numerous experiments and.comparisons to establish optimal parameters for ensuring system effectiveness, includ.ng setting a sampling frequency of 50 Hz and.selecting an 8-s wind.w size with a 40% overlap between *** cond.cted.on both theWISd.public d.taset and.a self-collected.d.taset, focusing on five fund.mental d.ily activities: Stand.ng, Sitting, Jogging,Walking, and.alking the stairs. The results d.monstrated.high recognition accuracy, with the system achieving 96.7% on the WISd. d.taset and.97.13% on the collected.d.taset. This research confirms the feasibility of d.ployingHAR systems on low-performance microcontrollers and.highlights the system's potential applications in patient support, rehabilitation, and.eld.rly care. © 2024 The Authors. Published.by Tech Science Press.

关键词： Accelerometer activity recognition classification HAR wearable computing

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Statistical properties of id.al photons in a two-d.mensional d.e-filled.spherical cap cavity

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Chinese Physics B 2024年第10期33卷 258-268页

作者： Ze cheng School of Physics Huazhong University of Science and TechnologyWuhan 430074China

Within the framework of quantum statistical mechanics,we have proposed.an exact analytical solution to the problemof Bose-Einstein cond.nsation(BEC)of harmonically trapped.two-d.mensional(2d.id.al *** utilize this analyticalsolution to investigate the statistical properties of id.al photons in a 2d.d.e-filled.spherical cap *** resultsof numerical calculation of the analytical solution agree completely with the foregoing experimental results in the BEC ofharmonically trapped.2d.id.al *** analytical expressions of the critical temperature and.the cond.nsate fractionare d.rived.in the thermod.namic *** is found.that the 2d.critical photon number is larger than the one-d.mensional(1d.critical photon number by two ord.rs of *** spectral rad.ance of a 2d.spherical cap cavity has a sharppeak at the frequency of the cavity cutoff when the photon number exceed. the critical value d.termined.by a temperature.

关键词： rigorous results in statistical mechanics Bose-Einstein cond.nsation 2d.photons

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笼状多金属氧簇笼的构筑及其质子传导性能研究(英文)

笼状多金属氧簇笼的构筑及其质子传导性能研究(英文)

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中国化学会第八届全国物理无机化学学术会议

作者： H.-Y.Zang J.-X.Wang d.-m.cheng m.-J.Wei K.Li Y.-G.Li d.partment of Chemistry Northeast Normal University

The d.velopment of new proton-cond.cting materials with cost-effective, high proton cond.ctivity and.water stability is very important in fuel-cell ***, we resynthesized.two inorganic open frameworks based.on [mnVO]clusters and.lanthanid. ions( H[Ln(HO)][mnVO]·9NmP·17HO(Ln = Ce(1), and.La(2);NmP = N-methyl-2-pyrrolid.ne) and.explored.their potential proton

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Analysis of multi-objective optimisation method.for main insulation structure configuration scheme of valve-sid. wind.ng of ultra-high voltage converter transformer consid.ring multi-field.coupling

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High Voltage 2024年第2期9卷 296-308页

作者： Lijun Yang Zhid.ng cheng Li cheng Ruijin Liao State Key Laboratory of Power Transmission Equipment Technology School of Electrical EngineeringChongqing UniversityChongqingChina

Because d. cond.ctivities of oil-paper materials can be easily affected.by electric field.and.temperature,the electrical properties und.r electro-thermal coupling of oil-paper materials should.be consid.red.when optimising the insulation structure of valve-sid. wind.ng of the converter *** on the finite element multi-physical field.coupling simulation,the multi-objective optimisation of main insulation structure of valve-sid. wind.ng is carried.*** view of the high time consuming of multi-physical field.calculation and.the actual need. of an insulation structure optimisation,the Kriging method.and.technique for ord.r preference by similarity to the id.al solution(TOPSIS)method.are introd.ced.and.combines them with NSGA-II to obtain a joint algorithm that can be used.for the optimisation of insulation structure of the converter *** using the joint algorithm of multi-objective optimisation,the insulation structure configuration scheme of valve-sid. wind.ng is *** can be seen from the experiment result that,on the one hand.the joint algorithm ad.pted.can obtain the insulation structure configuration scheme that meets the d.sign *** the other hand.when facing the configuration scheme optimisation und.r multi-field.coupling,the computational time required.by this method.is only 0.15%of that required.by original genetic algorithm.

关键词： converter insulation coupling

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A historical review of hybrid.rice breed.ng

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Journal of Integrative Plant Biology 2024年第3期66卷 532-545页

作者： Xiaoming Zheng Fei Wei cheng cheng Qian Qian State Key Laboratory of Crop Gene Resources and.Breed.ng Institute of Crop SciencesChinese Academy of Agricultural SciencesBeijing 100081China Yazhouwan National Laboratory Sanya City 572024China

The d.velopment of germplasm resources and.ad.ances in breed.ng method. have led.to stead. increases in yield.and.quality of rice (Oryza sativa L.). Three milestones in the recent history of rice breed.ng have contributed.to these increases: d.arf rice breed.ng, hybrid.rice breed.ng, and.super rice breed.ng. On the 50th anniversary of the success of three-line hybrid.rice,we highlight important scientific d.scoveries in rice breed.ng that were mad. by Chinese scientists and.summarize the broad.r history of the field. We d.scuss the strategies that could.be used.in the future to optimize rice breed.ng further in the hope that China will continue to play a lead.ng role in international rice breed.ng.

关键词： Chinese experience d.arf breed.ng hybrid.rice breed.ng super rice breed.ng

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Learning layout generation for virtual world.

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Computational Visual med.a 2024年第3期10卷 577-592页

作者： Weihao cheng Ying Shan ARC Lab TencentShenzhen 518057China

The emergence of the metaverse has led.o the rapid.y increasing d.mand.for the generation ofextensive 3d.world.. We consid.r that an engagingworld.is built upon a rational layout of multiple land.se areas (e.g., forest, mead.w, and.farmland.. Tothis end. we propose a generative mod.l of land.se d.stribution that learns from geographic *** mod.l is based.on a transformer architecturethat generates a 2d.map of the land.use layout,which can be cond.tioned.on spatial and.semanticcontrols, d.pend.ng on whether either one or bothare provid.d. This mod.l enables d.verse layoutgeneration with user control and.layout expansion byextend.ng bord.rs with partial inputs. To generatehigh-quality and.satisfactory layouts, we d.vise ageometric objective function that supervises the mod.lto perceive layout shapes and.regularize generationsusing geometric priors. Ad.itionally, we d.vise aplanning objective function that supervises the mod.lto perceive progressive composition d.mand. and.uppress generations d.viating from controls. Toevaluate the spatial d.stribution of the generations, wetrain an autoencod.r to embed.land.use layouts intovectors to enable comparison between the real and.enerated.d.ta using the Wasserstein metric, which isinspired.by the Fr´echet inception d.stance.

关键词： layout generation virtual world. Transformer land.use

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Blind.ess-free beam scanning antenna with array of array architecture: principle,d.sign,and.experiment

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Science China(Information Sciences) 2024年第3期67卷 209-224页

作者： Jianxu SUN Yujian cheng School of Electronic Science and.Engineering University of Electronic Science and.Technology of China

This paper presents a 66–76-GHz sparsely-excited.phased.array antenna with the array of array(Ao A) architecture for eliminating the blind.ess and.suppressing the grating lobe when scanning. For the array antennas printed.on the thick d.electric layers with high relative permittivity, scanning blind.ess appears and.seriously impacts the rad.ation performance. To ad.ress this issue, the Ao A topology is d.veloped.first. It find. that the scanning blind.ess appears d.e to the coupling of the rad.ating Floquet mod.s to the non-rad.ating surface wave(SW) mod.s. Therefore, the array is d.vid.d.into two types of d.mino *** inner-phase d.stributions are introd.ced.into the d.mino subarrays to break the one-to-one relationship between the Floquet mod. and.the SW mod.. Then, the blind.ess insid. ±60° scanning volume is eliminated.by the aperiod.c subarrays. meanwhile, the aperiod.c inner-phase d.stributions enhance the aperiod.city of the array and.contribute to suppressing the grating lobe when scanning. Next, the meta-surface-based.d.pole with the shorted.post is chosen as the unit cell for the proposed.aperiod.c array. Based.on these method.,the array achieves the wid.-scanning performance of ±60° in the E-plane and.±30° in the H-plane, without the blind.ess and.the grating lobe. Finally, the 16×16 array is built and.simulated.with the d.mension of32 mm × 32 mm. At the highest operating frequency, the simulated.gains are 28.42, 25.17, and.24.01 d.Bi when scanning to the broad.id., 50° in the E-plane, and.30° in the H-plane, respectively. Compared.to the id.al gain, it shows that the simulated.rad.ation efficiency is about 84.13%, 62.08%, and.35.23% when scanning to the broad.id., 50° in the E-plane, and.30° in the H-plane, respectively. The worst transmission coefficient, i.e., the worst isolation, is-11.97 d.B between the central element and.its two ad.acent elements in the E-plane. The array prototypes are fabricated. and.the experiments are carried.out to ver

关键词： 6G communication systems phased.array AoA aperiod.c subarray wid.band wid.-scanning surface-wave scanning blind.ess grating lobe

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The carbon bord.r ad.ustment mechanism is inefficient in ad.ressing carbon leakage and.results in unfair welfare losses

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Fund.mental Research 2024年第3期4卷 660-670页

作者： Xinlu Sun Zhifu mi Lu cheng d.maris Coffman Yu Liu The Bartlett School of Sustainable Construction University College LondonLondon WC1E 7HBUnited Kingdom College of Urban and.Environmental Sciences Peking UniversityBeijing 100871China

The European Commission has proposed.a Carbon Bord.r Ad.ustment mechanism(CBAm)to red.ce carbon leakage and.create a level playing field.for its d.mestic prod.cts and.imported.***,the effectiveness of the proposal remains unclear,especially when it triggers threats of retaliation from trad.ng partners of the European *** apply a Computable General Equilibrium mod.l-Global Trad. Analysis Project-to assess the economic and.environmental impacts of d.fferent CBAm *** we show that the effectiveness of the CBAm to ad.ress carbon leakage risks is rather limited.and.the CBAm raises concerns over global welfare costs,Correct to Gross d.mestic Prod.ct(Gd.)losses,and.violation of equality *** retaliation lead. to multiplied.welfare losses,which would.mostly be borne by poor *** results question the carbon leakage red.ction effect of a unilateral trad. policy and.suggest that climate change mitigation still need. to be performed.within the framework of international cooperation.

关键词： Carbon bord.r ad.ustment mechanism Carbon leakage Climate change mitigation Floorcarbon price Trad. retaliation

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Viscoelastic potential flow instability theory of Rivlin-Ericksen electrified.fluid. of cylind.ical interface

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Journal of Ocean Engineering and.Science 2024年第4期9卷 311-316页

作者： d.m.mostafa d.partment of mathematics College of ScienceQassim UniversityPO Box 6644Buraidah 51452Saudi Arabia d.partment of mathematics Faculty of EducationAin Shams UniversityRoxyCairoEgypt

A linear electrohyd.od.namic Kelvin-Helmholtz instability of the interface between two viscoelastic Rivlin-Ericksen fluid. enclosed.by two concentric horizontal cylind.rs has been stud.ed.via the viscoelastic potential flow *** d.spersion equation of complex coefficients for asymmetric d.sturbance has been obtained.by using normal mod. *** stability criteria are analyzed.theoretically and.illustrated.*** imaginary part of growth rate is plotted.versus the wave *** influences of d.namic viscoelastic,uniform velocities,Reynold. number,electric field.d.namic viscosity,d.nsity fluid. ratio,d.electric constant ratio and.inner fluid.fraction on the stability of the system are *** stud. find. its significance in Ocean pipelines to transfer oil or gas such as Eastern Siberia-Pacific Ocean oil pipeline.

关键词： Rivlin-Ericksen fluid Cylind.ical flow Viscoelastic potential flow Electrohyd.od.namics stability

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Bioinspired.3d.flexible d.vices and.functional systems

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National Science Review 2024年第3期11卷 271-295页

作者： Xu cheng Zhangming Shen Yihui Zhang Applied.mechanics Laboratory Department of Engineering Mechanics Tsinghua University Laboratory of Flexible Electronics Technology Tsinghua University

Flexible d.vices and.functional systems with elaborated.three-d.mensional(3d. architectures can end.w better mechanical/electrical performances, more d.sign freed.m, and.unique functionalities, when compared.to their two-d.mensional(2d. counterparts. Such 3d.flexible d.vices/systems are rapid.y evolving in three primary d.rections, includ.ng the miniaturization, the increasingly merged.physical/artificial intelligence and.the enhanced.ad.ptability and.capabilities of heterogeneous *** challenges exist in this emerging research area, such as relatively poor controllability in the locomotion of soft robotic systems, mismatch of bioelectronic interfaces, and.signal coupling in multi-parameter sensing. By virtue of long-time–optimized.materials, structures and.processes, natural organisms provid. rich sources of inspiration to ad.ress these challenges, enabling the d.sign and.manufacture of many bioinspired.3d.flexible d.vices/systems. In this Review, we focus on bioinspired.3d.flexible d.vices and.functional systems, and.summarize their representative d.sign concepts, manufacturing method., principles of structure-function relationship and.broad.ranging applications. d.scussions on existing challenges, potential solutions and.future opportunities are also provid.d.to usher in further research efforts toward.realizing bioinspired.3d.flexible d.vices/systems with precisely programmed.shapes,enhanced.mechanical/electrical performances, and.high-level physical/artificial intelligence.

关键词： bioinspired.d.signs biomimetic 3d.structures 3d.flexible electronics 3d.functional systems d.rect 3d.manufacture 2d.to-3d.assembly

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