期刊文献+
共找到26,123篇文章
< 1 2 250 >
每页显示 20 50 100
Impact of the carbon market on investment benefits of power-grid enterprises in China: a system dynamics analysis
1
作者 Wanning Mao Liang Hu +3 位作者 Wenjuan Niu Xiaorong Sun Lili Hao Abimbola Susan Ajagun 《Global Energy Interconnection》 EI CSCD 2024年第4期402-414,共13页
The power grid,as the hub connecting the power supply and consumption sides,plays an important role in achieving carbon neutrality in China.In emerging carbon markets,assessing the investment benefits of power-grid en... The power grid,as the hub connecting the power supply and consumption sides,plays an important role in achieving carbon neutrality in China.In emerging carbon markets,assessing the investment benefits of power-grid enterprises is essential.Thus,studying the impact of the carbon market on the investment and operation of powergrid enterprises is key to ensuring their efficient operation.Notably,few studies have examined the interaction between the carbon and electricity markets using system dynamics models,highlighting a research gap in this area.This study investigates the impact of the carbon market on the investment of power-grid enterprises using a novel evaluation system based on a system dynamics model that considers carbon-emissions from an established carbon-emission accounting model.First,an index system for benefit evaluation was constructed from six aspects:financing ability,economic benefit,reliability,social responsibility,user satisfaction,and carbon-emissions.A system dynamics model was then developed to reflect the causal feedback relationship between the impact of the carbon market on the investment and operation of power-grid enterprises.The simulation results of a provincial power-grid enterprise analyze comprehensive investment evaluation benefits over a 10-year period and the impact of carbon emissions on the investment and operation of power-grid enterprises.This study provides guidelines for the benign development of power-grid enterprises within the context of the carbon market. 展开更多
关键词 Carbon market Power-grid enterprises Investment benefit evaluation System dynamics analysis
下载PDF
Dynamic Analysis of A Deepwater Drilling Riser with A New Hang-off System
2
作者 LI Yan-wei LIU Xiu-quan +3 位作者 WANG Jin-long CHEN Guo-ming CHANG Yuan-jiang SHENG Lei-xiang 《China Ocean Engineering》 SCIE EI CSCD 2024年第1期29-41,共13页
The safety of risers in hang-off states is a vital challenge in offshore oil and gas engineering.A new hang-off system installed on top of risers is proposed for improving the security of risers.This approach leads to... The safety of risers in hang-off states is a vital challenge in offshore oil and gas engineering.A new hang-off system installed on top of risers is proposed for improving the security of risers.This approach leads to a challenging problem:coupling the dynamics of risers with a new hang-off system combined with multiple structures and complex constraints.To accurately analyze the dynamic responses of the coupled system,a coupled dynamic model is established based on the Euler-Bernoulli beam-column theory and penalty function method.A comprehensive analysis method is proposed for coupled dynamic analysis by combining the finite element method and the Newmarkβmethod.An analysis program is also developed in MATLAB for dynamic simulation.The simulation results show that the dynamic performances of the risers at the top part are significantly improved by the new hang-off system,especially the novel design,which includes the centralizer and articulation joint.The bending moment and lateral deformation of the risers at the top part decrease,while the hang-off joint experiences a great bending moment at the bottom of the lateral restraint area which requires particular attention in design and application.The platform navigation speed range under the safety limits of risers expands with the new hang-off system in use. 展开更多
关键词 deepwater drilling riser new hang-off system dynamic analysis finite element method penalty function method
下载PDF
Artificial Intelligence-Based Sentiment Analysis of Dynamic Message Signs that Report Fatality Numbers Using Connected Vehicle Data
3
作者 Dorcas O. Okaidjah Jonathan Wood Christopher M. Day 《Journal of Transportation Technologies》 2024年第4期590-606,共17页
This study presents results from sentiment analysis of Dynamic message sign (DMS) message content, focusing on messages that include numbers of road fatalities. As a traffic management tool, DMS plays a role in influe... This study presents results from sentiment analysis of Dynamic message sign (DMS) message content, focusing on messages that include numbers of road fatalities. As a traffic management tool, DMS plays a role in influencing driver behavior and assisting transportation agencies in achieving safe and efficient traffic movement. However, the psychological and behavioral effects of displaying fatality numbers on DMS remain poorly understood;hence, it is important to know the potential impacts of displaying such messages. The Iowa Department of Transportation displays the number of fatalities on a first screen, followed by a supplemental message hoping to promote safe driving;an example is “19 TRAFFIC DEATHS THIS YEAR IF YOU HAVE A SUPER BOWL DON’T DRIVE HIGH.” We employ natural language processing to decode the sentiment and undertone of the supplementary message and investigate how they influence driving speeds. According to the results of a mixed effect model, drivers reduced speeds marginally upon encountering DMS fatality text with a positive sentiment with a neutral undertone. This category had the largest associated amount of speed reduction, while messages with negative sentiment with a negative undertone had the second largest amount of speed reduction, greater than other combinations, including positive sentiment with a positive undertone. 展开更多
关键词 Intelligent Transportation System Sentiment analysis dynamic Message Signs Large Language Models Traffic Safety Artificial Intelligence
下载PDF
Review on dynamic analysis of road pavements under moving vehicles and plane strain conditions
4
作者 Edmond V.Muho Niki D.Beskou 《Journal of Road Engineering》 2024年第1期54-68,共15页
This paper reviews works on the dynamic analysis of flexible and rigid pavements under moving vehicles on the basis of continuum-based plane strain models and linear theories.The purpose of this review is to provide i... This paper reviews works on the dynamic analysis of flexible and rigid pavements under moving vehicles on the basis of continuum-based plane strain models and linear theories.The purpose of this review is to provide in-formation about the existing works on the subject,critically discuss them and make suggestions for further research.The reviewed papers are presented on the basis of the various models for pavement-vehicle systems and the various methods for dynamically analyzing these systems.Flexible pavements are modeled by a homogeneous or layered half-plane with isotropic or anisotropic and linear elastic,viscoelastic or poroelastic material behavior.Rigid pavements are modeled by a beam or plate on a homogeneous or layered half-plane with material properties like the ones for flexible pavements.The vehicles are modeled as concentrated or distributed over a finite area loads moving with constant or time dependent speed.The above pavement-vehicle models are dynamically analyzed by analytical,analytical/numerical or purely numerical methods working in the time or frequency domain.Representative examples are presented to illustrate the models and methods of analysis,demonstrate their merits and assess the effects of the various parameters on pavement response.The paper closes with con-clusions and suggestions for further research in the area.The significance of this research effort has to do with the presentation of the existing literature on the subject in a critical and easy to understand way with the aid of representative examples and the identification of new research areas. 展开更多
关键词 Flexible pavements Rigid pavements Moving vehicles Plane strain models dynamic analysis
下载PDF
Dynamical Modeling and Dynamic Characteristics Analysisof a Coaxial Dual-Rotor System
5
作者 Yubin Yue Hongjun Wang Shenglun Zhang 《Journal of Dynamics, Monitoring and Diagnostics》 2024年第2期99-111,共13页
The dual-rotor structure serves as the primary source of vibration in aero-engines. Understanding itsdynamical model and analyzing dynamic characteristics, such as critical speed and unbalanced response, arecrucial fo... The dual-rotor structure serves as the primary source of vibration in aero-engines. Understanding itsdynamical model and analyzing dynamic characteristics, such as critical speed and unbalanced response, arecrucial for rotor system dynamics. Previous work introduced a coaxial dual-rotor-support scheme for aeroengines,and a physical model featuring a high-speed flexible inner rotor with a substantial length-to-diameter ratiowas designed. Then a finite element (FE) dynamic model based on the Timoshenko beam elements and rigid bodykinematics of the dual-rotor system is modeled, with the Newmark method and Newton–Raphson method used forthe numerical calculation to study the dynamic characteristics of the system. Three different simulation models,including beam-based FE (1D) model, solid-based FE (3D) model, and transfer matrix model, were designed tostudy the characteristics of mode and the critical speed characteristic of the dual-rotor system. The unbalancedresponse of the dual-rotor system was analyzed to study the influence of mass unbalance on the rotor system. Theeffect of different disk unbalance phases and different speed ratios on the dynamic characteristics of the dual-rotorsystem was investigated in detail. The experimental result shows that the beam-based FE model is effective andsuitable for studying the dual-rotor system. 展开更多
关键词 coaxial dual-rotor system dynamical modeling dynamic characteristics analysis rotor dynamics
下载PDF
Optimization and Performance Analysis of Intelligent Video AI Dynamic
6
作者 Yu Xing 《Journal of Electronic Research and Application》 2024年第3期142-147,共6页
In today’s information age,video data,as an important carrier of information,is growing explosively in terms of production volume.The quick and accurate extraction of useful information from massive video data has be... In today’s information age,video data,as an important carrier of information,is growing explosively in terms of production volume.The quick and accurate extraction of useful information from massive video data has become a focus of research in the field of computer vision.AI dynamic recognition technology has become one of the key technologies to address this issue due to its powerful data processing capabilities and intelligent recognition functions.Based on this,this paper first elaborates on the development of intelligent video AI dynamic recognition technology,then proposes several optimization strategies for intelligent video AI dynamic recognition technology,and finally analyzes the performance of intelligent video AI dynamic recognition technology for reference. 展开更多
关键词 Intelligent video AI dynamic recognition Technology optimization Performance analysis
下载PDF
Dynamic Analysis of Customer Demand Based on Intuitionistic Fuzzy Number in Product Planning
7
作者 Yongguang Yi Zengqiang Wang 《Proceedings of Business and Economic Studies》 2024年第5期127-131,共5页
To address the fuzziness and variability in determining customer demand importance,a dynamic analysis method based on intuitionistic fuzzy numbers is proposed.First,selected customers use intuitionistic fuzzy numbers ... To address the fuzziness and variability in determining customer demand importance,a dynamic analysis method based on intuitionistic fuzzy numbers is proposed.First,selected customers use intuitionistic fuzzy numbers to represent the importance of each demand.Then,the preference information is aggregated using customer weights and time period weights through the intuitionistic fuzzy ordered weighted average operator,yielding a dynamic vector of the subjective importance of the demand index.Finally,the feasibility of the proposed method is demonstrated through an application example of a vibrating sorting screen. 展开更多
关键词 Quality function deployment Customer demand Intuitionistic fuzzy number dynamic analysis method
下载PDF
Design and dynamic analysis of a scissors hoop-rib truss deployable antenna mechanism
8
作者 Bo Han Xiangkun Li +3 位作者 Jian Sun Yundou Xu Jiantao Yao Yongsheng Zhao 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第6期399-413,共15页
As the support mechanism of space-borne antennas,space deployable antenna mechanism belongs to complex multi-closed-loop coupling mechanism,configuration design and dynamic analysis are more difficult than general par... As the support mechanism of space-borne antennas,space deployable antenna mechanism belongs to complex multi-closed-loop coupling mechanism,configuration design and dynamic analysis are more difficult than general parallel mechanism.In this paper,an unequal-length scissors mechanism(ULSM)is proposed by changing the position of the internal rotational joint through a basic scissors mechanism.A scissors hoop-rib truss deployable antenna mechanism(SHRTDAM)is constructed by replacing the parabolic rib with the ULSM.Kinematic analysis of SHRTDAM is conducted,and the degree of freedom(DOF)of the whole antenna mechanism is analyzed based on screw theory,the result showed that it has only one DOF.Velocity and acceleration characteristics of SHRTDAM are obtained by the screw derivative and rotation transformation.Based on Lagrange equation,dynamic model of this mechanism is established,the torque required to drive the mechanism is simulated and verified by Adams and MATLAB software.In addition,a ground experiment prototype of 1.5-m diameter was fabricated and a deployment test is conducted,which demonstrated the mobility and deployment performance of the whole mechanism.The mechanism proposed in this paper can provide a good reference for the design and analysis of large aperture space deployable antennas. 展开更多
关键词 Scissors mechanism Deployable antenna Screw theory Kinematic analysis dynamic analysis
下载PDF
Nonlinear dynamic response and stability analysis of the stapes reconstruction in human middle ear
9
作者 Lele WANG Liang WANG +7 位作者 Yueting ZHU Zhanli LIU Yongtao SUN Jie WANG Hongge HAN Shuyi XIANG Huibin SHI Qian DING 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2023年第10期1739-1760,共22页
Stapes fracture causes hearing loss and instability in the middle ear hearing system(MEHS). The material used in the stapes reconstruction restores stapes, but the effects of the nonlinear material parameters on the s... Stapes fracture causes hearing loss and instability in the middle ear hearing system(MEHS). The material used in the stapes reconstruction restores stapes, but the effects of the nonlinear material parameters on the stability of the MEHS are still unknown. To address this challenge, the nonlinear dynamic response and stability of the stapes reconstruction are investigated using a multi-degree-of-freedom mechanical model. The material parameters of the implant are tentatively determined by analyzing the natural frequencies of the undamped system. The dynamical properties of the MEHS are characterized under different external excitations. The approximate solution of the MEHS near the resonant frequency is derived through the multiple-time-scale method(MTSM). The results show that the nonlinear stiffness of the material has little influence on the MEHS in the healthy state, but it causes resonant phenomena between the ossicle and the implant in the pathological state. 展开更多
关键词 crus fracture of stapes stapes reconstruction dynamic analysis bifurcation analysis multiple-time-scale method(MTSM)
下载PDF
Dynamic analysis of bio-inspired helicoid laminated composite plates resting on Pasternak foundation excited by explosive loading
10
作者 Ngoc-Tu Do Quoc-Hoa Pham 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第12期126-140,共15页
This paper uses isogeometric analysis(IGA)based on higher-order shear deformation theory(HSDT)to study the dynamic response of bio-inspired helicoid laminated composite(B-iHLC)plates resting on Pasternak foundation(PF... This paper uses isogeometric analysis(IGA)based on higher-order shear deformation theory(HSDT)to study the dynamic response of bio-inspired helicoid laminated composite(B-iHLC)plates resting on Pasternak foundation(PF)excited by explosive loading.IGA takes advantage of non-uniform rational Bspline(NURBS)basic functions to exactly represent the structure geometry models and the attainment of higher-order approximation conditions.This method also ensures a C1 continuous function in the analysis of transverse shear deformation via HSDT.Furthermore,IGA eliminates the requirement for correction factors and delivers accurate results.Pasternak foundation with two stiffness parameters:springer stiffness(k_(1))and shear stiffness(k_(2)).The derivation of the governing equations is based on Hamilton's principle.The proposed method is validated through numerical examples.A comprehensive analysis of the impact of geometrical parameters,material properties,boundary conditions(BCs),and foundation stiffness on dynamic response of B-i HLC plates is carried out. 展开更多
关键词 Isogeometric analysis Pasternak foundation dynamic response Laminated composite
下载PDF
Linear analysis of the dynamic response of a riser subject to internal solitary waves
11
作者 Dalin TAN Xu WANG +1 位作者 Jinlong DUAN Jifu ZHOU 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2023年第6期1023-1034,共12页
The flow field induced by internal solitary waves(ISWs)is peculiar wherein water motion occurs in the whole water depth,and the strong shear near the pycnocline can be generated due to the opposite flow direction betw... The flow field induced by internal solitary waves(ISWs)is peculiar wherein water motion occurs in the whole water depth,and the strong shear near the pycnocline can be generated due to the opposite flow direction between the upper and lower layers,which is a potential threat to marine risers.In this paper,the flow field of ISWs is obtained with the Korteweg-de Vries(Kd V)equation for a two-layer fluid system.Then,a linear analysis is performed for the dynamic response of a riser with its two ends simply supported under the action of ISWs.The explicit expressions of the deflection and the moment of the riser are deduced based on the modal superposition method.The applicable conditions of the theoretical expressions are discussed.Through comparisons with the finite element simulations for nonlinear dynamic responses,it is proved that the theoretical expressions can roughly reveal the nonlinear dynamic response of risers under ISWs when the approximation for the linear analysis is relaxed to some extent. 展开更多
关键词 internal solitary wave(ISW) RISER dynamic response linear analysis
下载PDF
Dynamic Analysis of A Deep-Water Compliant Vertical Access Riser with A Variable Length During Installation
12
作者 LIANG Wei-xing LOU Min +1 位作者 WANG Yu ZHANG Rui 《China Ocean Engineering》 SCIE EI CSCD 2023年第4期568-579,共12页
Compliant vertical access risers(CVAR)have broad application prospects in deep-water oil and gas transportation.However,the mechanical behaviors of the CVAR with a variable length during installation remains unclear.T... Compliant vertical access risers(CVAR)have broad application prospects in deep-water oil and gas transportation.However,the mechanical behaviors of the CVAR with a variable length during installation remains unclear.To address this issue,based on the flexible segment method,a model of CVAR with a variable length during installation is established in this study,which is verified by the comparison with commercial software.Then,the mechanical behaviors of CVAR during installation are investigated.The results reveal that the CVAR configuration is significantly affected by the buoyancy blocks.The streamwise displacement of CVAR increases with the increase of current velocity.When the BOP weight is insuffcient,obvious upbending is observed in the lower region and transition region,leading to local compression.When the platform moves in the opposite direction to the current,the maximum stress is larger than that of the scenario when the platform moves in the same direction as the current. 展开更多
关键词 compliant vertical access riser installation analysis dynamic performance variable length
下载PDF
Comparison Study and Forensic Analysis between Experiment and Coupled Dynamics Simulation for Submerged Floating Tunnel Segment with Free Ends under Wave Excitations
13
作者 Woo Chul Chung Chungkuk Jin +1 位作者 Moo Hyun Kim Ju-young Hwang 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第10期155-174,共20页
This paper presents dynamic-behavior comparisons and related forensic analyses of a submerged floating tunnel(SFT)between numerical simulation and physical experiment under regular and irregular waves.The experiments ... This paper presents dynamic-behavior comparisons and related forensic analyses of a submerged floating tunnel(SFT)between numerical simulation and physical experiment under regular and irregular waves.The experiments are conducted in the 3Dwave tank with 1:33.3 scale,and the corresponding coupled time-domain simulation tool is devised for comparison.The entire SFT systemconsists of a long concrete tunnel and 12 tubular aluminummooring lines.Two numerical simulation models,the Cummins equation with 3D potential theory including second-order wave-body interaction effects and the much simpler Morison-equation-based formula with the lumped-massbased line model,are designed and compared.Forensic analyses for mooring-line adjustments in the simulation are carried out in view of the best representation of the physical system.After that,the measured pre-tension distribution and systemstiffness of twelvemooring lines arewell reproduced in the numericalmodel.Subsequently,the dynamic responses and mooring tensions of the SFT are compared under regular and irregular waves.The measured and simulated results coincide reasonably well for both regular-and irregular-wave conditions. 展开更多
关键词 Submerged floating tunnel comparative study forensic analysis mooring-line modeling dynamic response mooring tension
下载PDF
Dynamic response analysis of liquefiable ground due to sinusoidal waves of different frequencies of shield construction
14
作者 Wang Jingyue Ge Xinsheng +4 位作者 Sun Jingyuan Liu Yasheng Shang Zhuo Wang Zhiqiang Tian Maoguo 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2023年第3期637-646,共10页
Vibration induced by shield construction can lead to liquefaction of saturated sand.Based on FLAC3D software,a numerical model of tunnel excavation is established and sinusoidal velocity loads with different frequenci... Vibration induced by shield construction can lead to liquefaction of saturated sand.Based on FLAC3D software,a numerical model of tunnel excavation is established and sinusoidal velocity loads with different frequencies are applied to the excavation face.The pattern of the excess pore pressure ratio with frequency,as well as the dynamic response of soil mass under different frequency loads before excavation,is analyzed.When the velocity sinusoidal wave acts on the excavation surface of the shield tunnel with a single sand layer,soil liquefaction occurs.However,the ranges and locations of soil liquefaction are different at different frequencies,which proves that the vibration frequency influences the liquefaction location of the stratum.For sand-clay composite strata with liquefiable layers,the influence of frequency on the liquefaction range is different from that of a single stratum.In the frequency range of 5-30 Hz,the liquefaction area and surface subsidence decrease with an increase in vibration frequency.The research results in this study can be used as a reference in engineering practice for tunneling liquefiable strata with a shield tunneling machine. 展开更多
关键词 shield tunnel liquefiable formation FLAC3D numerical simulation excess pore pressure ratio dynamic response analysis
下载PDF
Dynamic Modeling and Sensitivity Analysis for an MEA-Based CO_(2) Capture Absorber
15
作者 Hongwei Guan Lingjian Ye +2 位作者 Yurun Wang Feifan Shen Yuchen He 《Intelligent Automation & Soft Computing》 SCIE 2023年第6期3535-3550,共16页
The absorber is the key unit in the post-combustion monoethanolamine(MEA)-based carbon dioxide(CO_(2))capture process.A rate-based dynamic model for the absorber is developed and validated using steady-state experimen... The absorber is the key unit in the post-combustion monoethanolamine(MEA)-based carbon dioxide(CO_(2))capture process.A rate-based dynamic model for the absorber is developed and validated using steady-state experimental data reported in open literature.Sensitivity analysis is performed with respect to important model parameters associated with the reaction,mass transport and phy-sical property relationships.Then,a singular value decomposition(SVD)-based subspace parameter estimation method is proposed to improve the model accu-racy.Finally,dynamic simulations are carried out to investigate the effects of the feed rate of lean MEA solution and the flue inlet conditions.Simulation results indicate that the established dynamic model can reasonably reflect the physical behavior of the absorber.Some new insights are gained from the simulation results. 展开更多
关键词 CO_(2)capture dynamic modeling sensitivity analysis model validation
下载PDF
Mechanical analysis of the femoral neck dynamic intersection system with different nail angles and clinical applications
16
作者 Ying Wang Jian-Xiong Ma +4 位作者 Hao-Hao Bai Bin Lu Lei Sun Hong-Zhen Jin Xin-Long Ma 《World Journal of Clinical Cases》 SCIE 2023年第20期4814-4823,共10页
BACKGROUND The femoral neck dynamic intersection system(FNS)is mechanically more stable than other internal fixation techniques.Current studies have confirmed that the structural design of FNS has good biomechanical p... BACKGROUND The femoral neck dynamic intersection system(FNS)is mechanically more stable than other internal fixation techniques.Current studies have confirmed that the structural design of FNS has good biomechanical properties in European and American populations.However,whether the suitability of the FNS's 130°main nail angle design for Asian populations has been thoroughly investigated remains unclear.AIM To compare the biomechanical stability differences among different main nail angles of the FNS in the treatment of femoral neck fractures in Asian populations.METHODS Computed tomography data of the femur of healthy adult male volunteers were imported into Mimics software to create a three-dimensional model of the femur.The model was adapted to the curve using Geomagic software and imported into Solidworks software to construct the Pauwels I femoral neck fracture model and design the FNS internal fixation model using different main nail angles.Afterward,the models were assembled with the FNS fracture model and meshed using the preprocessing Hypermesh software.Subsequently,they were imported into Abaqus software to analyze and evaluate the biomechanical effects of different angles of the FNS main nail on the treatment of femoral neck fractures.RESULTS The peak displacement of the proximal femur under different angles of FNS fixation under stress was 7.446 millimeters in the 120°group and 7.416 millimeters in the 125°group;in the 130°,135°,and 140°FNS fixation groups,the peak displacement was 7.324 millimeters,8.138 millimeters,and 8.246 millimeters,respectively.In the 120°and 125°FNS fixation groups,the maximum stresses were concentrated at the main nail and the anti-rotation screw,which intersected the fracture line of the femur neck,resulting in peak stresses of 200.7 MPa and 138.8 MPa,respectively.Peak stresses of 208.8 MPa,219.8 MPa,and 239.3 MPa were observed on the angular locking plate distal to the locking screw in the 130°,135°,and 140°fixation groups.CONCLUSION FNS has significant stress distribution properties,a minimal proximal femoral displacement,and an optimal stability for treating femoral neck fractures in Asian populations when performed with a 130°main nail angle. 展开更多
关键词 Femoral neck dynamic intersection system BIOMECHANICS Three-dimensional reconstruction Nail angle Finite element analysis Stress
下载PDF
Time Series Analysis and Prediction of COVID-19 Pandemic Using Dynamic Harmonic Regression Models
17
作者 Lei Wang 《Open Journal of Statistics》 2023年第2期222-232,共11页
Rapidly spreading COVID-19 virus and its variants, especially in metropolitan areas around the world, became a major health public concern. The tendency of COVID-19 pandemic and statistical modelling represents an urg... Rapidly spreading COVID-19 virus and its variants, especially in metropolitan areas around the world, became a major health public concern. The tendency of COVID-19 pandemic and statistical modelling represents an urgent challenge in the United States for which there are few solutions. In this paper, we demonstrate combining Fourier terms for capturing seasonality with ARIMA errors and other dynamics in the data. Therefore, we have analyzed 156 weeks COVID-19 dataset on national level using Dynamic Harmonic Regression model, including simulation analysis and accuracy improvement from 2020 to 2023. Most importantly, we provide new advanced pathways which may serve as targets for developing new solutions and approaches. 展开更多
关键词 dynamic Harmonic Regression with ARIMA Errors COVID-19 Pandemic Forecasting Models Time Series analysis Weekly Seasonality
下载PDF
An Educational GUI-Based Software for Dynamic Analysis of Framed Structural Models
18
作者 Claudio H. B. Resende Pedro C. Lopes +2 位作者 Rafael L. Rangel Luis F. Paullo Muñoz Luiz F. Martha 《Journal of Software Engineering and Applications》 2023年第7期265-286,共22页
This paper introduces a new version of the open-source educational software, LESM (Linear Elements Structure Model), developed in MATLAB for structural analysis of one-dimensional models such as frames, trusses, and g... This paper introduces a new version of the open-source educational software, LESM (Linear Elements Structure Model), developed in MATLAB for structural analysis of one-dimensional models such as frames, trusses, and grillages. The updated program includes dynamic analysis, which incorporates inertial and damping effects, time-dependent load conditions, and a transient solver with multiple time integration schemes. The software assumes small displacements and linear-elastic material behavior. The paper briefly explains the theoretical basis for these developments and the reorganization of the source code using Object-Oriented Programming (OOP). The updated Graphical User Interface (GUI) allows interactive use of dynamic analysis features and displays new results such as animations, envelope diagrams of internal forces, phase portraits, and the response of degrees-of-freedom in time and frequency domain. The new version was used in a structural dynamics course, and new assignments were elaborated to improve students’ understanding of the subject. 展开更多
关键词 Structural analysis Structural dynamics Educational Software MATLAB Graphical User Interface
下载PDF
Rocky Desertification Dynamic Analysis and the Development of Management Information System 被引量:12
19
作者 颜学莉 谢世友 《Agricultural Science & Technology》 CAS 2008年第2期45-48,92,共5页
With the background of severe rocky desertification in the west of China and the ohjective of ecological environment construction and poverty elimination, the management information system of rocky desertification was... With the background of severe rocky desertification in the west of China and the ohjective of ecological environment construction and poverty elimination, the management information system of rocky desertification was designed according to the natural and humane characteristics in Nanchuan of Sichuan Province. The system was composed of data management module, information query module for rocky desertification, spatial analysis module and dynamic monitoring module. 展开更多
关键词 Rocky desertification Inforumtion system dynamic analysis Nanchuan
下载PDF
Dynamics Analysis of Close-coupling Multiple Helicopters System 被引量:9
20
作者 赵志刚 吕恬生 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2008年第1期71-78,共8页
The particularity and practicality of harmony operations of close-coupling multiple helicopters indicate that the researches on it are urgent and necessary, Using the model that describes two hovering helicopters carr... The particularity and practicality of harmony operations of close-coupling multiple helicopters indicate that the researches on it are urgent and necessary, Using the model that describes two hovering helicopters carrying one heavy load, an inertia coordinate system and body coordinate systems of each sub-system are established. A nonlinear force model is established too. The equilibrium computation results can be regarded as the reference control inputs of the flight control system under hovering or low-speed flight condition. After the establishment of a translation kinematics model and a posture kinematics model, a coupling dynamics model of the multiple helicopter system is set up. The results can also be regarded as the base to analyze stabilization and design a controller for a close-coupling multiple helicopters harmony operation system. 展开更多
关键词 close-coupling multiple helicopters harmony operation equilibrium computation kinematics analysis dynamics analysis
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部