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TransCrowd: weakly-supervised crowd counting with transformers

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Science China(Information Sciences) 2022年第6期65卷 48-61页

作者： Dingkang LIANG Xiwu CHEN Wei XU Yu zhou Xiang BAI School of Artificial Intelligence and Automation Huazhong University of Science and Technology School of Electronic Information and Communication Huazhong University of Science and Technology School of Artificial Intelligence Beijing University of Posts and Telecommunications

The mainstream crowd counting methods usually utilize the convolution neural network(CNN)to regress a density map, requiring point-level annotations. However, annotating each person with a point is an expensive and laborious process. During the testing phase, the point-level annotations are not considered to evaluate the counting accuracy, which means the point-level annotations are redundant. Hence,it is desirable to develop weakly-supervised counting methods that just rely on count-level annotations, a more economical way of labeling. Current weakly-supervised counting methods adopt the CNN to regress a total count of the crowd by an image-to-count paradigm. However, having limited receptive fields for context modeling is an intrinsic limitation of these weakly-supervised CNN-based methods. These methods thus cannot achieve satisfactory performance, with limited applications in the real world. The transformer is a popular sequence-to-sequence prediction model in natural language processing(NLP), which contains a global receptive field. In this paper, we propose TransCrowd, which reformulates the weakly-supervised crowd counting problem from the perspective of sequence-to-count based on transformers. We observe that the proposed TransCrowd can effectively extract the semantic crowd information by using the self-attention mechanism of transformer. To the best of our knowledge, this is the first work to adopt a pure transformer for crowd counting research. Experiments on five benchmark datasets demonstrate that the proposed TransCrowd achieves superior performance compared with all the weakly-supervised CNN-based counting methods and gains highly competitive counting performance compared with some popular fully-supervised counting methods.

关键词： crowd counting visual transformer weakly supervised crowd analysis transformer

Urea electrooxidation-boosted hydrogen production on nitrogen-doped porous carbon nanorod-supported nickel phosphide nanoparticles

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Journal of Energy Chemistry 2022年第9期31卷 88-96,I0003页

作者： Xiaoyu Zhang Ge Ma Lingling Shui Guofu zhou Xin Wang South China Academy of Advanced Optoelectronics&International Academy of Optoelectronics at Zhaoqing South China Normal UniversityGuangzhou 510631GuangdongChina

Urea electro-oxidation reaction(UEOR)-boosted water electrolysis can supplant the kinetics-restricted oxygen evolution reaction(OER)and provide an energy-saving method of hydrogen ***,low UEOR activity and the poisoning issue of the catalyst limit its practical ***,a simple coordination reaction is used to synthesize the dimethylglyoxime-NiⅡcomplex(DMGNiⅡ),which efficiently serves as the initial precursor to synthesize nitrogen-doped carbon nanorodsupported nickel phosphide nanoparticle(Ni_(2)P/N-C)*** density functional theory calculations and electrochemical results reveal that nitrogen doping can weaken the adsorption of hydrogen and the generated CO_(2)resulting in an enhancement of hydrogen evolution reaction(HER)and UEOR *** addition,N-doping can also promote the generation of Ni,which can further promote the UEOR and HER ***,the overpotential for the HER on Ni_(2)P/N-C-2h nanocomposites is only 201 m V at 10 mA cm,and the onset potential of the UEOR on NiP/NC-2h nanocomposites is only 1.34 ***,the Ni_(2)P/N-Cnanocomposites also show excellent long-term stability due to the introduction of nitrogen-doped carbon ***,the symmetric Ni_(2)P/N-C-2h||Ni_(2)P/N-C-2h urea electrolyzer requires 1.41 V of electrolysis voltage for urea electrolysis,which can be applied in energy-saving H_(2) production and environment purification.

关键词： Electrochemical water splitting Nitrogen-doped carbon Nickel phosphide nanoparticles Urea oxidation reaction Electrolysis voltage

Coupled relationships among anammox,denitrification, and dissimilatory nitrate reduction to ammonium along salinity gradients in a Chinese estuarine wetland

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Journal of Environmental Sciences 2021年第8期33卷 39-46页

作者： Zijun zhou Lei Ge Yufang Huang Yuqian Liu Siyang Wang Institute of Yellow River Water Resources Protection Zhengzhou 450003China Yellow River Institute of Hydraulic Research Zhengzhou 450003China

Salinization in estuarine wetlands significantly alters the balance between their nitrogen(N)removal and retention abilities but these processes have not yet been characterized *** the present study,the potential rates of sediment denitrification,anaerobic ammonium oxidation(anammox),and dissimilatory nitrate reduction to ammonium(DNRA)were mapped using N isotope tracing methods along salinity gradients across the Yellow River Delta wetland(YRDW)in *** contribution of anammox to total dissimilatory N transformations in YRDW was merely 6.8%,whereas denitrification and DNRA contributed 52.3%and 40.9%,*** potential rate of denitrification(5.82μmol/kg/h)decreased significantly along salinity gradients and markedly exceeded DNRA potential rate(2.7μmol/kg/h)in fresh wetlands,but was lower than that of DNRA in oligohaline wetlands(3.06 and 3.18μmol/kg/h,respectively).Moreover,a significantly positive relationship between salinity and DNRA/denitrification was obeserved,indicating that increased salinity may favor DNRA over ***,total sulfur(TS)content and ratio of total organic carbon to total nitrogen(C/N)increased with the salinity gradient and showed evident positive relationships with the DNRA/denitrification *** this study,we proved that increased salinization resulted in the dominance of DNRA over denitrification,possible through the addition of S and alteration of the C/N in estuarine wetlands,leading to increased N retention in estuarine wetlands during salinization,which would enhance the eutrophication potential within wetlands and in downstream ecosystems.

关键词： Denitrification Anammox DNRA Salinity C/N ratio

Mechanical Properties and Deformation Mechanisms of Metallic Glasses Under Hydrostatic Pressure

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Acta Mechanica Solida Sinica 2023年第3期36卷 390-404页

作者： Haiming Lu Yao Tang Fanheng Jiang Panpan Wan Haofei zhou Center for X-Mechanics Department of Engineering MechanicsZhejiang UniversityHangzhou 310027China

Metallic glasses(MGs)are promising structural materials with high strength,large elastic strain limit and enhanced wear *** the way to tune the mechanical performance of MGs,numerous efforts have been devoted to investigating the effect of hydrostatic pressure(σh)on the mechanical properties and deformation mechanisms of *** application of sufficiently large magnitudes ofσh to MGs has been considered a feasible way to improve strength and delocalize plastic deformation in *** this paper,we review recent studies on pressure-dependent thermodynamic properties,mechanical strength and hardness,as well as elevated ductility of MGs due to the pressure-induced change of deformation and failure *** of intriguing mechanical behaviors of MGs,and the corresponding theoretical modeling and atomistic understanding of plastic deformation in MGs under pure hydrostatic pressure and more general stress states are *** findings not only deepen the understanding of pressure-dependent mechanical behaviors of MGs,but also point out the potential of tuning mechanical behaviors of MGs through stress engineering.

关键词： Metallic glass Hydrostatic pressure Mechanical property Deformation mechanism Microstructure

An Adaptive Many-objective Robust Optimization Model of Dynamic Reactive Power Sources for Voltage Stability Enhancement

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Journal of Modern Power Systems and Clean Energy 2023年第6期11卷 1756-1769页

作者： Yuan Chi Anqi Tao Xiaolong Xu Qianggang Wang Niancheng zhou IEEE State Key Laboratory of Power Transmission Equipment and System Security and New Technology Chongqing UniversityChongqing 400044China

The deployment of dynamic reactive power sourcecan effectively improve the voltage performance after a disturbance for a power system with increasing wind power penetration level and ubiquitous induction *** improve the voltage stability of the power system,this paper proposes an adaptive many-objective robust optimization model to deal with thedeployment issue of dynamic reactive power ***,two metrics are adopted to assess the voltage stability of the system at two different stages,and one metric is proposed to assess the tie-line reactive power ***,a robustness index isdeveloped to assess the sensitivity of a solution when subjectedto operational uncertainties,using the estimation of acceptablesensitivity region(ASR)and D-vine *** objectives areoptimized simultaneously:①total equipment investment;②adaptive short-term voltage stability evaluation;③tie-line power flow evaluation;④prioritized steady-state voltage stabilityevaluation;and⑤robustness ***,an anglebased adaptive many-objective evolutionary algorithm(MaOEA)is developed with two improvements designed for the application in a practical engineering problem:①adaptive mutationrate;and②elimination procedure without a requirement for athreshold *** proposed model is verified on a modifiedNordic 74-bus system and a real-world power *** results demonstrate the effectiveness and efficiency of theproposed model.

关键词： Voltage stability reactive power planning robust many-objective optimization tie-line correlated uncertainty

Manipulating d-d orbital hybridization induced by Mo-doped Co_(9)S_(8) nanorod arrays for high-efficiency water electrolysis

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Journal of Energy Chemistry 2024年第6期93卷 592-600,I0015页

作者： Xue zhou Jing Li Guangyao zhou Weiran Huang Yucan Zhang Jun Yang Huan Pang Mingyi Zhang Dongmei Sun Yawen Tang Lin Xu Jiangsu Key Laboratory of New Power Batteries Jiangsu Collaborative Innovation Centre of Biomedical Functional MaterialsSchool of Chemistry and Materials ScienceNanjing Normal UniversityNanjing 210023JiangsuChina 'College of Science Jinling Institute of TechnologyNanjing 211169JiangsuChina State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China Nanjing IPE Institute of Green Manufacturing Industry Nanjing 211100JiangsuChina School of Chemistry and Chemical Engineering Yangzhou UniversityYangzhou 225009JiangsuChina Key Laboratory for Photonic and Electronic Bandgap Materials Ministry of EducationSchool of Physics and Electronic EngineeringHarbin Normal UniversityHarbin 150025HeilongjiangChina

Precisely refining the electronic structure of electrocatalysts represents a powerful approach to further optimize the electrocatalytic ***,we demonstrate an ingenious d-d orbital hybridization concept to construct Mo-doped Co_(9)S_(8) nanorod arrays aligned on carbon cloth(CC)substrate(abbreviated as Mo-Co_(9)S_(8)@CC hereafter)as a high-efficiency bifunctional electrocatalyst toward water *** has experimentally and theoretically validated that the 4d-3d orbital coupling between Mo dopant and Co site can effectively optimize the H_(2)O activation energy and lower H^(*)adsorption energy barrier,thereby leading to enhanced hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)*** to the unique electronic and geometrical advantages,the optimized Mo-Co_(9)S_(8)@CC with appropriate Mo content exhibits outstanding bifunctional performance in alkaline solution,with the overpotentials of 75 and 234 mV for the delivery of a current density of 10 mA cm^(-2),small Tafel slopes of 53.8 and 39.9 mV dec~(-1)and long-term stabilities for at least 32 and 30 h for HER and OER,*** impressively,a water splitting electrolylzer assembled by the self-supported Mo-Co_(9)S_(8)@CC electrode requires a low cell voltage of 1.53 V at 10 mA cm^(-2)and shows excellent stability and splendid reversibility,demonstrating a huge potential for affordable and scalable electrochemical H_(2) *** innovational orbital hybridization strategy for electronic regulation herein provides an inspirable avenue for developing progressive electrocatalysts toward new energy systems.

关键词： d-d orbital hybridization Transition metal sulfides Nanorods arrays Water electrolysis

Whole-infrared-band camouflage with dual-band radiative heat dissipation

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Light(Science & Applications) 2023年第11期12卷 2391-2401页

作者： Bing Qin Yining Zhu Yiwei zhou Min Qiu Qiang Li State Key Laboratory of Modern Optical Instrumentation College of Optical Science and EngineeringZhejiang UniversityHangzhou 310027China Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province School of EngineeringWestlake University18 Shilongshan RoadHangzhou 310024 ZhejiangChina Institute of Advanced Technology Westlake Institute for Advanced Study18 Shilongshan RoadHangzhou 310024 ZhejiangChina

Advanced multispectral detection technologies have emerged as a significant threat to objects,necessitating the use of multiband ***,achieving effective camouflage and thermal management across the entire infrared spectrum,especially the short-wave infrared(SWIR)band,remains *** paper proposes a multilayer wavelength-selective emitter that achieves effective camouflage across the entire infrared spectrum,including the near-infrared(NIR),SWIR,mid-wave infrared(MWIR),and long-wave infrared(LWIR)bands,as well as the visible(VIS)***,the emitter enables radiative heat dissipation in two non-atmospheric windows(2.5-3μm and 5-8μm).The emitter’s properties are characterized by low emittance of 0.270/0.042/0.218 in the SWIR/MWIR/LWIR bands,and low reflectance of 0.129/0.281 in the VIS/NIR ***,the high emittance of 0.742/0.473 in the two non-atmospheric windows ensures efficient radiative heat dissipation,which results in a temperature decrement of 14.4℃ compared to the Cr reference at 2000Wm^(−2) input power *** work highlights the role of solar radiance in camouflage,and provides a comprehensive guideline for developing multiband camouflage compatible with radiative heat dissipation,from the visible to LWIR.

关键词： dissipation visible radiative

A multifunctional osteogenic system of ultrasonically spray deposited bone-active coatings on plasma-activated magnesium

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Journal of Magnesium and Alloys 2023年第8期11卷 2719-2739页

作者： Hui Fang Shicheng zhou Xiaoyun Qi Chenxi Wang Yanhong Tian State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China

Biomimetic bone-active coatings composed of inorganic nano-hydroxyapatite(i.e.,nHA)and organic silk fibroin(i.e.,SF)are layer-by-layer deposited on Mg-Zn-Ca alloy by a controllable ultrasonic spray ***,plasma activation is developed as a promising strategy to pretreat magnesium surfaces,which facilitates the direct adhesion of coatings with enhanced bonding *** this work,we engineer the nHA/SF composite coatings with excellent mechanical properties and adhesion *** optimized parameters of ultrasonic spray bring significant influence on the surface morphologies of *** by hybrid plasma of oxygen and nitrogen(i.e.,O_(2)/N_(2) plasma),the activated Mg-Zn-Ca surfaces are uniformly covered by a robust and compact nHA/SF composite coating,establishing a multifunctional system with superior corrosion resistance and biological ***,secondary oxygen plasma treatment of nHA/SF coatings(A-nHA/SF)promotes the hydrophilicity,leading to a rapid self-repair effect from surface *** improvement of anti-corrosion and self-repair provides a dependable platform for better cell adhesion,proliferation,spreading and *** favorable factors contribute to the preferable in vivo biocompatibility and the promotion of newly formed bones for the A-nHA/SF-coated Mg *** study lays important foundations for coating strategy on biomedical magnesium alloy as multifunctional osteogenic system in bioactive implantable applications.

关键词： Magnesium alloy Hydroxyapatite Silk fibroin Biocompatibility Self-repair

New measurements on hydrodynamics in a gas-liquid-solid expanded bed

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Particuology 2021年第5期19卷 276-284页

作者： Xiuhong zhou Yongli Ma Mingyan Liu Yixian Zhu Jiaming Zhang School of Chemical Engineering and Technology Tianjin UniversityTianjin 300350China State Key Laboratory of Chemical Engineering Tianjin UniversityTianjin 300350China China Energy Longyuan Environmental Protection Co. Ltd.Beijing 100039China

The solid holdup,in a 150 mm-ID×2460 mm-height gas-liquid-solid expanded bed with air,water and glass beads(the diameter of particles is 0.6-0.8 mm)was firstly investigated based on the immersion-type online multiphase measuring instrument,and bubble behavior was studied via the BVW-2 double electrical conductivity *** effect of the superficial gas velocity and liquid velocity on the expanded ratio,the transition ratio,the bubble rising velocity,the gas holdup and the solid holdup was *** is discovered that compared with the gas velocity,the liquid velocity has stronger impact on the expanded ratio,but it is opposite for the transition *** average gas holdup and solid holdup increase linearly as the superficial gas velocity goes *** it,the gas holdup increases greater in the center,while the solid holdup increases greater near the *** with it,when the superficial liquid velocity rises,the average gas holdup hardly changes,but the average solid holdup keeps decreasing,especially the solid holdup distributes flatter with the increase of the superficial liquid velocity.

关键词： Phase holdup Gas-liquid-solid expanded bed Immersion-type online multiphase measuring instrument BVW-2 double electrical conductivity probe