检索结果-内蒙古大学图书馆

7th IEEE International Conference on transportation Information and Safety, ICTIS 2023

作者： Li, Xinyuan Zhang, Di Chen, Chen Wan, Chengpeng Cao, Jingjing Wuhan University of Technology Sanya Science and Education Innovation Park Wuhan China Wuhan University of Technology Intelligent Transportation Systems Research Center Wuhan China Wuhan University of Technology State Key Laboratory of Maritime Technology and Safety Wuhan China Wuhan University of Technology School of Transportation and Logistics Engineering Wuhan China Wuhan Business University School of Business Administration Wuhan China Inland Port and Shipping Industry Research Co. Ltd. of Guangdong Province Wuhan China

ISBN: (纸本)9798350308532

Accurate forecasting of container freight volume demand at ports is crucial to the social production and investment decisions of businesses. When dealing with complex, nonlinear fluctuations and ambiguous demand time series, the current methods for forecasting freight volume have demonstrated poor accuracy. In view of this, this study proposes a container freight volume forecasting model using Particle Swarm optimization (PSO)-based Variational Mode Decomposition (VMD) and Gated Recurrent Units (GRU). Within the proposed design. In particular, VMD is used to decompose the original time series, which reduces the prediction error caused by disturbances and abrupt changes in the original series. In the meantime, PSO is utilized to optimize the parameter selection of VMD in order to attain the optimal decomposition effect. After decomposition, GRU is utilized to accurately predict each intrinsic mode function (IMF). The final prediction result is obtained by superimposing the predictions of each IMF component. Compared to a BP neural network, a single GRU model, and a support vector machine (SVM), the root mean square error (RMSE), the mean absolute error (MAE), and the mean absolute percent error (MAPE) of the proposed model are smaller, and its prediction accuracy is greater than that of the comparison model. © 2023 IEEE.

关键词： Variational mode decomposition

来源：评论

学校读者我要写书评

暂无评论

Energy flow characteristics of friction-induced nonlinear vibrations in a water-lubricated bearing-shaft coupled system

引用

Acta Mechanica Sinica 2021年第4期37卷 679-704,I0003页

作者： Li Qin Hongling Qin Jing Tang Xing Key Laboratory of Metallurgical Equipment and Control Technology School of Machinery&AutomationWuhan University of Science and TechnologyWuhan 430081China Hubei Key Laboratory of Hydroelectric Machinery Design&Maintenance Three Gorges UniversityYichang 443002China Maritime Engineering Group CMEESchool of EngineeringFaculty of Engineering&Physical SciencesUniversity of SouthamptonSouthampton SO 171BJUK

Based on the energy flow theory of nonlinear dynamical system,the stabilities,bifurcations,possible periodical/chaotic motions of nonlinear water-lubricated bearing-shaft coupled systems are investigated in this *** is revealed that the energy flow characteristics around the equlibrium point of system behaving in the three types with different friction-para-mters.(a)Energy flow matrix has two negative and one positive energy flow factors,constructing an attractive local zero-energy flow surface,in which free vibrations by initial disturbances show damped modulated oscillations with the system tending its equlibrium state,while forced vibrations by external forces show stable oscillations,(b)Energy flow matrix has one negative and two positive energy flow factors,spaning a divergence local zero-energy flow surface,so that the both free and forced vibrations are divergence oscillations with the system being unstable,(c)Energy flow matrix has a zero-energy flow factor and two opposite factors,which constructes a local zero-energy flow surface dividing the local phase space into stable,unstable and central subspace,and the simulation shows friction self-induced unstable vibrations for both free and forced *** a set of friction parameters,the system behaves a periodical oscillation,where the bearing motion tends zero and the shaft motion reaches a stable limit circle in phase space with the instant energy flow tending a constant and the time averaged one tending *** simulations have not found any possible chaotic motions of the *** is discovered that the damping matrices of cases(a),(b)and(c)respectively have positive,negative and zero diagonal elements,resulting in the different dynamic behavour of system,which gives a giderline to design the water-lubricated bearing unit with expected performance by adjusting the friction parameters for applications.

关键词： Nonlinear friction-induced vibrations Nonlinear energy flows Nonlinear water-lubricated bearing-shaft systems Bifucation friction parameters Energy flow matrices Periodical oscilation

来源：评论

学校读者我要写书评

暂无评论

Uncertainties of landslide susceptibility prediction:Influences of different spatial resolutions,machine learning models and proportions of training and testing dataset

Rock Mechanics Bulletin

引用

Rock Mechanics Bulletin 2023年第1期2卷 65-81页

作者： Faming Huang Zuokui Teng Zizheng Guo Filippo Catani Jinsong Huang Jiangxi Provincial Key Laboratory of Interdisciplinary Science Nanchang UniversityNanchang330031China School of Infrastructure Engineering Nanchang UniversityNanchang330031China School of Civil and Transportation Engineering Hebei University of TechnologyTianjin300401China Department of Geosciences University of PadovaPadovaItaly Discipline of Civil Surveying and Environmental EngineeringPriority Research Centre for Geotechnical Science and EngineeringUniversity of NewcastleNSWAustralia

This study aims to reveal the impacts of three important uncertainty issues in landslide susceptibility prediction(LSP),namely the spatial resolution,proportion of model training and testing datasets and selection of machine learning *** Yanchang County of China as example,the landslide inventory and 12 important conditioning factors were *** frequency ratios of each conditioning factor were calculated under five spatial resolutions(15,30,60,90 and 120 m).Landslide and non-landslide samples obtained under each spatial resolution were further divided into five proportions of training and testing datasets(9:1,8:2,7:3,6:4 and 5:5),and four typical machine learning models were applied for LSP *** results demonstrated that different spatial resolution and training and testing dataset proportions induce basically similar influences on the modeling *** a decrease in the spatial resolution from 15 m to 120 m and a change in the proportions of the training and testing datasets from 9:1 to 5:5,the modelling accuracy gradually decreased,while the mean values of predicted landslide susceptibility indexes increased and their standard deviations *** sensitivities of the three uncertainty issues to LSP modeling were,in order,the spatial resolution,the choice of machine learning model and the proportions of training/testing datasets.

关键词： Landslide susceptibility prediction Uncertainty analysis Machine learning models Conditioning factors Spatial resolution Proportions of training and testing dataset

来源：评论

学校读者我要写书评

暂无评论

Rapid Conjunction Screening Based Collision Avoidance for Mega-constellations with Coverage and Thrust Constraints 73

Rapid Conjunction Screening Based Collision Avoidance for Me...

引用

73rd International Astronautical Congress, IAC 2022

作者： Guo, Hao Long, Jiateng Cui, Pingyuan Zhu, Shengying Nie, Tao School of Aerospace Engineering Beijing Institute of Technology Beijing100081 China Key Laboratory of Autonomous Navigation and Control for Deep Space Exploration Ministry of Industry and Information Technology Beijing100081 China

In recent years, low Earth orbit (LEO) mega-constellations, composed of hundreds to thousands of satellites to provide global broadband even including the most rural areas, have been designed and launched by commercial aerospace companies, such as OneWeb and SpaceX. For these mega-constellations, however, one of the most significant threats to the safe operation is the collision of constellation to the active/inactive satellites, rocket bodies, debris, etc. Such collisions may result in catastrophic damage to the spacecraft operating environment. Therefore, the collision avoidance maneuver (CAM) strategy must be considered for the safe operation of the constellation. In order to properly conduct the CAM, conjunction screening is the first and essential step, which is to distinguish the satellite that need to be maneuvered. However, compared with the conventional CAM strategy of a single satellite, that of the mega-constellations is much more complicated, mainly because of the enormous quantity of satellites. This leads to conjunction screening incredibly slow even infeasible for online purpose application. What is worse is that mega-constellations have limited maneuverability, and the coverage of the satellite is sensitive to its position, compared with traditional navigation satellite constellations. To this end, a rapid conjunction screening based collision avoidance method considering coverage and thrust constraints is proposed. In view of global coverage, constellations are generally distributed in several orbital planes with dozens of satellites. To expedite the conjunction screening step, the threatened orbital planes are screened out firstly by evaluating the minimum miss distance between the danger space object and the orbital planes. Then, the satellites in the plane that need to perform CAM can be determined by the orbital period and the time of closest approach. Consequently, the computational complexity is related to the number of orbital planes rather t

关键词： Satellites

来源：评论

学校读者我要写书评

暂无评论

Surface-enhanced Raman scattering for mixing state characterization of individual fine particles during a haze episode in Beijing,China

引用

Journal of Environmental Sciences 2021年第6期33卷 216-224页

作者： Hui Chen Fengkui Duan Jingjing Du Ranhao Yin Lidan Zhu Jinlu Dong Kebin He Zhenli Sun Suhua Wang MOE Key Laboratory of Resources and Environmental System Optimization College of Environmental Science and EngineeringNorth China Electric Power UniversityBeijing 102206China State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084China State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China Guangdong Provincial Key Laboratory of Petrochemcial Pollution Processes and Control School of Environmental Science and EngineeringGuangdong University of Petrochemical TechnologyMaoming 525000China

The nondestructive characterization of the mixing state of individual fine particles using the traditional single particle analysis technique remains a *** this study,fine particles were collected during haze events under different pollution levels from September 5 to 112017 in Beijing,China.A nondestructive surface-enhanced Raman scattering(SERS)technique was employed to investigate the morphology,chemical composition,and mixing state of the multiple components in the individual fine *** image and SERS spectral analysis results show that soot existing in the form of opaque material was predominant during clear periods(PM_(2.5)≤75μg/m^(3)).During polluted periods(PM_(2.5)>75μg/m^(3)),opaque particles mixed with transparent particles(nitrates and sulfates)were generally *** classical least squares analysis further identified the relative abundances of the three major components of the single particles:soot(69.18%),nitrates(28.71%),and sulfates(2.11%).A negative correlation was observed between the abundance of soot and the mass concentration of PM_(2.5).Furthermore,mapping analysis revealed that on hazy days,PM_(2.5)existed as a core-shell structure with soot surrounded by nitrates and *** mixing state analysis method for individual PM_(2.5)particles provides information regarding chemical composition and haze formation mechanisms,and has the potential to facilitate the formulation of haze prevention and control policies.

关键词： PM_(2.5) Surface-enhanced Raman scattering Individual fine particle Nitrate Sulfate Soot

来源：评论

学校读者我要写书评

暂无评论

Design of broadband and low-profile polarization artificial structure for the application of low scattering control 15

Design of broadband and low-profile polarization artificial ...

引用

15th International Conference on Microwave and Millimeter Wave technology, ICMMT 2023

作者： Li, Fengxia Chen, Haiyan Deng, Jing-Ya Xidian University School of Physics Xi'an710071 China University of Electronic Science and Technology of China National Engineering Research Center of Electromagnetic Radiation Control Materials Key Laboratory of Multi-Spectral Absorbing Materials and Structures of Ministry of Education State Key Laboratory of Electronic Thin Film and Integrated Device Chengdu610054 China

ISBN: (纸本)9798350338874

here, we proposed a broadband and low-profile polarization artificial structure which based on SRR resonant rings, this structure also has the property of high-efficiency and wide-angle. The polarization conversion ratio is over 90% from 8.6 GHz to 23.9 GHz. The low-scattering metasurface for radar cross section (RCS) reduction is designed by arranging the polarization conversion unit and its mirror unit as the checkerboard type according to the phase cancellation principle. The relative bandwidth of 10dB RCS reduction is up to 93%, and the maximum reduction value reaches to 43.7dB. Such a low-scattering metasurface scheme has applications in scattering control, stealth, and security. © 2023 IEEE.

关键词： Polarization

来源：评论

学校读者我要写书评

暂无评论

Diversification of flavonoid accumulation among ecotypes of Agriophyllum squarrosum(L.)*** response to drought stress

引用

Journal of Arid Land 2025年第4期17卷 538-559页

作者： ZHAO Pengshu YAN Xia QIAN Chaoju MA Guorong FANG Tingzhou YIN Xiaoyue ZHOU Shanshan LIAO Yuqiu SHI Liang FAN Xingke Awuku IBRAHIM MA Xiaofei Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions of Gansu Province Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Inland River Ecohydrology Cold and Arid Regions Environmental and Engineering ResearchNorthwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China Gulang County Sand Prevention and Control Technology Promotion Center Wuwei 733100China

Agriophyllum squarrosum(L.)Moq.,commonly known as sandrice,is an annual medicinal plant prevalent in the dunes across China's deserts.A garden trial revealed that flavonoid content varies among sandrice ecotypes due to long-term local adaptation to water *** investigate how sandrice responds to drought stress through the molecular metabolic regulation of flavonoids,we employed transcriptomic and metabolomic analyses during a 9-d ambient drought stress,examining three ecotypes along a precipitation *** three ecotypes located in Dengkou(DK)County,Dulan(DL)County,and Aerxiang(AEX)village of northern China,which had 137,263,and 485 mm precipitation,*** moisture content was 4.04%after drought stress,causing seedlings of the three sandrice ecotypes to display collapsed structures,yellowing leaves,wilting,and *** these,DL exhibited superior drought tolerance,in which plant height increase(PHI)and leaf area(LA)were significantly higher than those of DK and ***-targeted metabolomics identified that rutin,isoquercitrin,and astragalin constituted over 95.00%of the 15 flavonoid metabolites detected.A total of 12 differentially accumulated flavonoids(DAFs)were found,with rutin being the most abundant(1231.57-2859.34 ng/100 mg fresh weight(FW)),showing a gradual increase along the precipitation *** analysis revealed 14 common differentially expressed genes(DEGs)associated with flavonoid synthesis among the three *** analysis of DEGs and DAFs indicated that sandrice adapts to drought stress by activating different flavonoid synthesis *** DK,the dihydrokaempferol-dihydroquercetin pathway,regulated by flavonoid 3'-monooxygenase(CYP75B1),likely enhances drought *** AEX,transcriptional repression by O-methylatransferase(OMT)shifts the metabolic flux from the quercetin-isorhamnetin pathway to the quercetin-isoquercetin-rutin pathway in response to ***,the most droughttole

关键词： drought tolerance ecotype flavonoid medicinal plant rutin

来源：评论

学校读者我要写书评

暂无评论

Development and Optimization of a WebGL-Based Mechanical Model Simulation Platform 4th

Development and Optimization of a WebGL-Based Mechanical Mod...

引用

4th International Conference on Mechanical Design and Simulation, MDS 2024

作者： Wang, Xintong Tian, Hao Fang, Jingzhe Zhang, Hualiang Zhang, Tao Software College Shenyang University of Technology Liaoning Shenyang China Shenyang Institute of Automation Chinese Academy of Sciences Shenyang China School of Electrical Engineering Shenyang University of Technology Shenyang China Institutes for Robotics and Intelligent Manufacturing Chinese Academy of Sciences Shenyang China Key Laboratory of Networked Control Systems Chinese Academy of Sciences Shenyang China

ISBN: (纸本)9789819778867

The need for mechanical model simulation platforms is growing as a result of the ongoing advancements in digital technology and the mechanical manufacturing sector. The application scope and efficacy of simulation platforms are severely limited by the issue of sluggish rendering performance, which frequently arises when obtaining high-quality rendering. When drawing high demand mechanical models, a lot of processing power is frequently needed, which makes real-time rendering speed unsatisfactory for practical purposes. In order to achieve real-time rendering and simulation of 3D robots, this experiment built and implemented a WebGL-based 3D simulation platform. Additionally, the simulation platform can be optimized by increasing frame rate and rendering speed without sacrificing rendering effect by building a mixed bounding box. © The Author(s) 2025.

关键词： Digital elevation model

来源：评论

学校读者我要写书评

暂无评论

Research on the Solution of the Thermo-Hydro-Mechanical-Chemical Coupling Model Based on the Unified Finite Volume Method Framework

SSRN

引用

SSRN 2024年

作者： Zhang, Weitao Han, Dongxu Wang, Bohong Chen, Yu-Jie Jiao, Kaituo Gong, Liang Yu, Bo Qingdao266580 China School of Mechanical Engineering Beijing Key Laboratory of Pipeline Critical Technology and Equipment for Deepwater Oil and Gas Development Beijing Institute of Petrochemical Technology Beijing102617 China National-Local Joint Engineering Laboratory of Harbour Oil and Gas Storage and Transportation Technology Zhejiang Key Laboratory of Petrochemical Environmental Pollution Control Zhejiang Ocean University No.1 Haida South Road Zhoushan316022 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

Most existing thermo-hydro-chemical-mechanical (THMC) coupling models for enhanced geothermal systems (EGS) employ a combination of finite volume method (FVM) and extended finite element method (XFEM), facing challenges in framework integration, programming complexity, and solution efficiency. To overcome these limitations, this study develops an innovative FVM-XFVM model based on the embedded discrete fracture model (EDFM) that significantly enhances the THMC coupling modeling process for fractured reservoirs with simplicity and efficiency. Rigorous comparative verification demonstrates the new model maintains accuracy while improving computational performance. For EGS applications, this model effectively captures spatiotemporal dynamics of coupled THMC processes with multi-component water-rock reactions. The approximately 3°C temperature deviation between multi-component and single-component models after long-term operation demonstrates the necessity of incorporating multi-component reactions into THMC models for accurate forecasts. This work substantially improves the predictability and efficiency of long-term heat production forecasts for EGS reservoirs. © 2024, The Authors. All rights reserved.

关键词： Finite volume method

来源：评论

学校读者我要写书评

暂无评论

A machine learning based solver for pressure Poisson equations

引用

Theoretical & Applied Mechanics Letters 2022年第5期12卷 315-321页

作者： Ruilin Chen Xiaowei Jin Hui Li Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of Industry and Information Technology Harbin Institute of TechnologyHarbin 150090China Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education Harbin Institute of TechnologyHarbin 150090China Guangdong-Hong Kong-Macao Joint Laboratory for Data-Driven Fluid Mechanics and Engineering Applications Harbin Institute of Technology(Shenzhen)Shenzhen 518055China

When using the projection method(or fractional step method)to solve the incompressible Navier-Stokes equations,the projection step involves solving a large-scale pressure Poisson equation(PPE),which is computationally expensive and *** this study,a machine learning based method is proposed to solve the large-scale *** machine learning(ML)-block is used to completely or partially(if not sufficiently accurate)replace the traditional PPE iterative solver thus accelerating the solution of the incompressible Navier-Stokes *** ML-block is designed as a multi-scale graph neural network(GNN)framework,in which the original high-resolution graph corresponds to the discrete grids of the solution domain,graphs with the same resolution are connected by graph convolution operation,and graphs with different resolutions are connected by down/up prolongation *** well trained MLblock will act as a general-purpose PPE solver for a certain kind of flow *** proposed method is verified via solving two-dimensional Kolmogorov flows(Re=1000 and Re=5000)with different source *** the premise of achieving a specified high precision(ML-block partially replaces the traditional iterative solver),the ML-block provides a better initial iteration value for the traditional iterative solver,which greatly reduces the number of iterations of the traditional iterative solver and speeds up the solution of the *** experiments show that the ML-block has great advantages in accelerating the solving of the Navier-Stokes equations while ensuring high accuracy.

关键词： Pressure Poisson equation Machine learning Projection method Multi-scale GNN

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：