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HWD-YOlO: A New Vision-Based Helmet Wearing Detection method

Computers, materials and Continua 2024年第3期80卷 4543-4560页

作者： Sun l. li H. Wang l. College of Information Science and Technology Beijing University of Technology Beijing 100124 China Chinese Institute of Coal Science Beijing 100013 China State Key laboratory for Intelligent Coal mining and Strata Control Beijing 100013 China Engineering Research Center of Digital Community of ministry of Education Beijing 100124 China

It is crucial to ensure workers wear safety helmets when working at a workplace with a high risk of safety accidents, such as construction sites and mine tunnels. Although existing methods can achieve helmet detection in images, their accuracy and speed still need improvements since complex, cluttered, and large-scale scenes of real workplaces cause server occlusion, illumination change, scale variation, and perspective distortion. So, a new safety helmet-wearing detection method based on deep learning is proposed. Firstly, a new multi-scale contextual aggregation module is proposed to aggregate multi-scale feature information globally and highlight the details of concerned objects in the backbone part of the deep neural network. Secondly, a new detection block combining the dilate convolution and attention mechanism is proposed and introduced into the prediction part. This block can effectively extract deep features while retaining information on fine-grained details, such as edges and small objects. moreover, some newly emerged modules are incorporated into the proposed network to improve safety helmet-wearing detection performance further. Extensive experiments on open dataset validate the proposed method. It reaches better performance on helmet-wearing detection and even outperforms the state-of-the-art method. To be more specific, the mAP increases by 3.4%, and the speed increases from 17 to 33 fps in comparison with the baseline, You Only look Once (YOlO) version 5X, and the mean average precision increases by 1.0% and the speed increases by 7 fps in comparison with the YOlO version 7. The generalization ability and portability experiment results show that the proposed improvements could serve as a springboard for deep neural network design to improve object detection performance in complex scenarios. Copyright © 2024 The Authors. Published by Tech Science Press.

关键词： attention mechanism deep learning feature extraction Object detection safety helmet wearing detection

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modelling dynamic pantograph loads with combined numerical analysis

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Railway Engineering Science 2024年第1期32卷 81-94页

作者： F.F.Jackson R.mishra J.m.Rebelo J.Santos P.Antunes J.Pombo H.magalhaes l.Wills m.Askill School of Computing and Engineering University of HuddersfieldHuddersfieldUK School of Computing and Engineering Institute of Railway ResearchUniversity of HuddersfieldHuddersfieldUK IDmEC Instituto Superior TecnicoUniversidade de LisboaLisbonPortugal ISEl Instituto Politecnico de LisboaLisbonPortugal Hitachi Rail Newton AycliffeUK Wabtec/Brecknell Willis ChardUK

Appropriate interaction between pantograph and catenary is imperative for smooth operation of electric *** heights of overhead lines to accommodate level crossings,overbridges,and tunnels pose significant challenges in maintaining consistent current collection performance as the pantograph aerodynamic profile,and thus aerodynamic load changes significantly with operational *** research aims to analyse the global flow characteristics and aerodynamic forces acting on individual components of an HSX pantograph operating in different configurations and orientations,such that the results can be combined with multibody simulations to obtain accurate dynamic insight into contact ***,computational fluid dynamics simulations are used to investigate the pantograph component loads in a representative setting,such as that of the recessed cavity on a Class 800 *** an aerodynamic perspective,this study indicates that the total drag force acting on non-fixed components of the pantograph is larger for the knuckle-leading orientation rather than the knuckle-trailing,although the difference between the two is found to reduce with increasing pantograph *** the aerodynamic loads acting on individual components with multibody tools allows for realistic dynamic insight into the pantograph *** results obtained show how considering aerodynamic forces enhance the realism of the models,leading to behaviour of the pantograph-catenary contact forces closely matching that seen in experimental tests.

关键词： Pantograph-catenary interaction Pantograph aerodynamics Computational fluid dynamics Pantograph loads Current collection performance

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measuring Impact of lean manufacturing Tools for Continuous Improvement on Economic Sustainability

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Journal of Systems Science and Systems Engineering 2024年第4期33卷 452-474页

作者： luis Javier márquez Figueroa Jorge luis García-Alcaraz Ahmed I.Osman Alfonso Jesús Gil lópez Yashar Aryanfar mika Sillanpää mamdouh El Haj Assad Department of Electrical Engineering and Computer Science Universidad Autónoma de Ciudad JuárezCiudad JuárezChihuahuaMéxico Department of Industrial Engineering and manufacturing Universidad Autónoma de Ciudad JuárezCiudad JuárezChihuahuaMéxico School of Chemistry and Chemical Engineering Queens UniversityBelfastNorthern IrelandUK Department of Economic and managerial Sciences University of La RiojaLa RiojaSpain Department of Chemical Engineering University of JohannesburgJohannesburgSouth Africa Department of Sustainable and Renewable Energy Engineering University of SharjahSharjahUAE

Using lean manufacturing(lm)tools in production processes is crucial for companies’economic,environmental,and social sustainability *** study shows a structural equation model(SEm)that shows the relationship between lm Tools like Kaizen(KAI),Gemba(GEm),Value Stream mapping(VSm)and Key Performance Indicator(KPI)with Economic Sustainability(ECS).Seven hypotheses were evaluated with data from 179 responses to a questionnaire about the mexican maquiladora industry,showing that these variables are *** a 95%confidence level,the model was evaluated using the partial least squares *** findings indicate that the relationships between KAI and GEm and KAI and VSm have the strongest relationship,followed by VSm and ECS;however,VSm has the strongest effect on *** on these findings,it is recommended that managers adopt a continuous improvement(KAI)approach based on working directly on the shop floor(GEm and VSm)to support their decisions regarding economic growth(ECS).

关键词： lean manufacturing economic sustainability structural equation model quality improvement

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Special Properties of morita Contexts

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Algebra Colloquium 2024年第2期31卷 309-322页

作者： Kamal Paykan l.A.Bokut Department of mathematics Tafresh UniversityTafreshIran 不详

In this paper we continue the study of various ring theoretic properties of morita *** and sufficient conditions are obtained for a general morita context or a trivial morita context or a formal triangular matrix ring to satisfy a certain ring property which is among being Kasch,completely primary,quasi-duo,2-primal,NI,semiprimitive,projective-free,*** also characterize when a general morita context is weakly principally quasi-Baer or strongly right mininjective.

关键词： morita context formal triangular matrix ring Kasch quasi-duo Köthe's conjecture weakly principally quasi-Baer

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Cognition and movement in neurodegenerative disorders:a dynamic duo

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Neural Regeneration Research 2024年第10期19卷 2101-2102页

作者： marit F.l.Ruitenberg Department of Health Medical and NeuropsychologyLeiden UniversityLeidenthe Netherlands leiden Institute for Brain and Cognition Leidenthe Netherlands

People with neurodegenerative disorders often experience problems across a variety of functional domains,including cognition,movement,and psychosocial *** classification of these disorders is based on the phenotypical manifestations that represent the most prominent clinical *** example,Parkinson's disease and Huntington's disease are typically regarded as movement disorders,whereas Alzheimer's disease(AD) and other dementias are regarded as cognitive disorders.

关键词： disorders Huntington degenerative

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Frequency-dependent viscoelasticity effects on the wave attenuation performance of multi-layered periodic foundations

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Applied mathematics and mechanics(English Edition) 2024年第3期45卷 407-424页

作者： m.SAFI m.VAKIlIFARD m.J.mAHmOODI Faculty of Civil Water&Environmental EngineeringShahid Beheshti UniversityTehran ***Iran Faculty of mechanical and Energy Engineering Shahid Beheshti UniversityTehran ***Iran

In this paper,layered periodic foundations(lPFs)are numerically examined for their responses to longitudinal and transverse modes in the time and frequency *** different unit-cells,i.e.,2-layer,4-layer,and 6-layer unit-cells,comprising concrete/rubber,concrete/rubber/steel/rubber,and concrete/rubber/steel/rubber/lead/rubber materials,respectively,are taken into ***,the viscoelasticity behavior of the rubber is modeled with two factors,i.e.,a frequency-independent(FI)loss factor and a linear frequency-dependent(FD)loss *** the extraction of the complex dispersion curves and the identification of the band gaps(BGs),the simulations of wave transmission in the time and frequency domains are performed using the COmSOl *** parametric studies evaluate the effects of the rubber viscoelasticity models on the dispersion curves and the wave transmission for the longitudinal and transverse *** results show that considering the rubber viscoelasticity enhances the wave attenuation ***,the transverse-mode damping is more sensitive to the viscoelasticity model than its longitudinal *** 6-layer unit-cell lPF exhibits the lowest BG,ranging from 4.8 Hz to 6.5 Hz.

关键词： layered metamaterial periodic foundation complex dispersion curve wave transmission diagram

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Analysis of the Impact of the Blazhko Effect Both on the Van Hoof Effect and Radial Velocity Amplitude in the Star RR lyr

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Research in Astronomy and Astrophysics 2024年第6期24卷 253-272页

作者： Y.El jariri F.l.Sefyani A.Benhida Z.Benkhaldoun K.Kolenberg K.Chafouai A.Habib m.Sabil Observatoire de l'Oukaimeden LPHEAFSSMUniversitéCadi AyyadMarrakech2390Morocco Observatoire de l'Oukaimeden LPHEAFSTGUniversitéCadi AyyadMarrakech549Morocco Département de physique Universitéd'Anvers Avenue Groenenborger 171Anvers2020Belgium lICPm ENSA-BMUniversitéSultan Moulay SlimaneBeni-Mellal23020Morocco

The Van Hoof effect is a phase shift existing between the radial velocity curves of hydrogen and metallic lines within the atmosphere of pulsating *** this article,we present a study of this phenomenon through the spectra of the brightest pulsating star RR lyr of RR lyrae stars recorded for 22 *** based ourselves,on the one hand,on 1268 spectra(41 nights of observation)recorded between the years 1994 and 1997 at the Observatory of Haute Provence(OHP,France)previously observed by Chadid and Gillet,and on the other hand on 1569 spectra(46nights of observation)recorded at our Oukaimeden Observatory(morocco)between 2015 and *** this study,we have detected information on atmospheric dynamics that had not previously been ***,the Van Hoof effect which results in a clear correlation between the radial velocities of hydrogen and those of the metallic lines has been observed and analyzed at different Blazhko phases.A correlation between the radial velocities of different metallic lines located in the lower atmosphere has been observed as *** the first time,we were able to show that the amplitude of the radial velocity curves deduced from the lines of hydrogen and that of FeⅡ(λ4923.921?)increases toward the minimum of the Blazhko cycle and decreases toward the maximum of the same Blazhko ***,we found that the Van Hoof effect is also modulated by the Blazhko ***,toward the minimum of the Blazhko cycle the Van Hoof effect is more visible and at the maximum of the Blazhko cycle,this effect is *** also observed the temporal evolution of the amplitudes of the radial velocities of the lower and upper *** observed over a long time,we can interpret it as a function of the Blazhko phases.

关键词： stars:atmospheres stars:variables:RR lyrae shock waves techniques:spectroscopic techniques:radial velocities stars:individual(RR lyr)

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Generation of millijoule-level sub-5 fs violet laser pulses

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High Power laser Science and Engineering 2024年第2期12卷 33-40页

作者： Xinhua Xie Yi Hung Yunpei Deng Adrian l.Cavalieri Andrius Baltuška Steven l.Johnson SwissFEl Paul Scherrer InstituteVilligen PSISwitzerland Photonics Institute Technische Universität WienViennaAustria Institute of Applied Physics University of BernBernSwitzerland Institute for Quantum Electronics Physics DepartmentETH ZurichZurichSwitzerland

We demonstrate the generation,spectral broadening and post-compression of second harmonic pulses using a thin beta barium borate(BBO)crystal on a fused-silica substrate as the nonlinear interaction *** combining second harmonic generation in the BBO crystal with self-phase modulation in the fused-silica substrate,we efficiently generate millijoule-level broadband violet pulses from a single optical *** second harmonic spectrum covers a range from long wave ultraviolet(down to 310 nm)to visible(up to 550 nm)with a bandwidth of 65 ***,we compress the second harmonic beam to a duration of 4.8 fs with a pulse energy of 0.64 mJ(5 fs with a pulse energy of 1.05 mJ)using chirped *** all-solid free-space apparatus is compact,robust and pulse energy scalable,making it highly advantageous for generating intense second harmonic pulses from near-infrared femtosecond lasers in the sub-5 fs regime.

关键词： post-compression second harmonic generation self-phase modulation supercontinuum generation

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Complex-frequency waves:beat loss and win sensitivity

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light(Science & Applications) 2024年第2期13卷 181-183页

作者： Qingqing Cheng Tao l School of Optical-Electrical and Computer Engineering University of Shanghai for Science and TechnologyShanghai200093China Department of Respiratory Diseases and Critical medicine Quzhou Hospital Affiliated to Wenzhou Medical UniversityQuzhou324000China National laboratory of Solid State microstructures College of Engineering and Applied SciencesNanjing UniversityNanjing210093China

Recent experiments have demonstrated that synthesized complex-frequency waves can impart a virtual gain to molecule sensing systems,which can effectively restore information lost due to intrinsic molecular *** enhancement notably amplifies the signal of trace molecular vibrational fingerprints,thereby substantially improving the upper limit of sensitivity.

关键词： thereby Complex limit

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mechanics and physics under supergravity conditions

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Acta mechanica Sinica 2024年第6期40卷 1-2页

作者： Chaofeng lü Chao Sun Shengqiang Cai Faculty of mechanical Engineering and mechanics Ningbo UniversityNingbo 315211China New Cornerstone Science laboratory Center for Combustion EnergyDepartment of Energy and Power EngineeringTsinghua UniversityBeijing 100084China Department of mechanical and Aerospace Engineering University of CaliforniaSan DiegoLa Jolla CA 92093USA

"Supergravity"refers to the conditions where the effective gravity is greater than that of *** conditions are generally relevant to stellar evolution,geophysical movement,astrophysical flows,and *** also frequently occur in various engineering scenarios involving acceleration,such as the launch of space shuttles,operation of rotor engines,impacts and explosions,chemical separation processes,and overloaded testing *** is already demonstrated in physiological experiments that living organisms of animals or plants could be damaged,either temporarily or permanently,when subjected to *** create supergravity conditions for scientific research on the Earth,centrifugal equipment or rapidly rotating devices are omnipresent in various fields,such as aerospace engineering,geophysical science,chemical and biomedical engineering,nuclear engineering,rotating flows,and physical modeling tests.

关键词： geophysical Earth stellar

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