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Analysing taxi customer-search behaviour using Copula-based joint model

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Transportation Safety and Environment 2022年第1期4卷 49-62页

作者： Helai Huang Zhenyuan Fang Yiwei Wang Jinjun Tang Xin Fu Smart Transportation Key Laboratory of Hunan Province School of Traffic and Transportation EngineeringCentral South UniversityChangsha 410075China School of Transportation engineering Chang’an UniversityXi’an 710064China engineering research center of highway infrastructure digitalization Ministry of EducationXi’an 710064China

The drivers of vacant taxis tend to cruise the road network searching new passengers,which leads to additional traffic congestion,air pollution and other *** study introduces a Copula-based joint model to analyse destination selection and route choice behaviour in the customer-search process.A multinomial logit model is used to analyse the destination selection behaviour,and a path size logit model is used to explore the routes choice ***,the joint model applied Copula function is then established to analyse the correlation between these two *** destination customer generation rate,destination distance,route customer generation rate,path travel time,cumulative intersection delay,path size and route length are selected as explanatory *** taxis trajectory data were collected by global positioning system in Xidan District of Beijing City from September 2014 to February *** the log-likelihood,Bayesian information criterion as evaluation indexes to measure the fitting result,the joint model applied Copula function has the highest *** effect of explanatory variables on customer search behaviour is discussed based on the parameter estimation *** results of this study are helpful to understand the customer-search behaviour of taxi drivers to reduce operating costs and improve the efficiency of the taxi operation system.

关键词： customer-search behaviour destination selection route choice model Copula function taxi trajectory data

Lessons in bridge damage learned from the Wenchuan earthquake

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Earthquake engineering and engineering Vibration 2009年第2期8卷 275-285页

作者： W. Phillip Yen Genda Chen Mark Yashinski Youssef Hashash Curtis Holu Wang Kehai GuoXiaodong Turner-Fairbank highway research center of Federal highway Administration （FWHA） center for Transportation infrastructure and Safety （CTIS） a National University Transportation Center at Missouri University of Science and Technology California Department of Transportation Representing the Earthquake engineering research Institute （EERI） University of Illinois at Urbana Champaign and Representing Geo-engineering Earthquake Reconnaissance （GEER） Mid-America Earthquake center （MAE） University of Illinois at Urbana Champaign research Institute of highway the Ministry of Communication of China Sichuan Province highway Planning Survey Design and Research Institute China

A strong earthquake occurred in Wenchuan County, Sichuan Province, China, on May 12, 2008. Shortly after the earthquake, the Turner-Fairbank highway research center of the Federal highway Administration, in partnership with the research Institute of highways, the Ministry of Communication of China, led a reconnaissance team to conduct a post-earthquake bridge performance investigation of the transportation system in the earthquake affected areas. The U.S. transportation system reconnaissance team visited the area during July 20 24, 2008. This paper presents the findings and lessons learned by the team.

关键词： earthquake engineering bridge engineering post earthquake investigation

GPR Wave Propagation Model in a Complex Geoelectric Structure Using Conformal First-Order Symplectic Euler Algorithm

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Computers, Materials & Continua 2019年第8期61卷 793-816页

作者： Man Yang Hongyuan Fang Juan Zhang Fuming Wang Jianwei Lei Heyang Jia College of Water Conservancy&Environmental engineering Zhengzhou UniversityZhengzhou450001China National Local Joint engineering Laboratory of Major infrastructure Testing and Rehabilitation Technology Zhengzhou450001China Collaborative Innovation center of Water Conservancy and Transportation infrastructure Safety Zhengzhou450001China CCCC First highway Consultants Co. LTDShanxi ProvinceXi’an710065China

Possessing advantages such as high computing efficiency and ease of programming,the Symplectic Euler algorithm can be applied to construct a groundpenetrating radar(GPR)wave propagation numerical model for complex geoelectric ***,the Symplectic Euler algorithm is still a difference algorithm,and for a complicated boundary,ladder grids are needed to perform an approximation process,which results in a certain amount of ***,grids that are too dense will seriously decrease computing *** paper proposes a conformal Symplectic Euler algorithm based on the conformal grid technique,amends the electric/magnetic fieldupdating equations of the Symplectic Euler algorithm by introducing the effective dielectric constant and effective permeability coefficient,and reduces the computing error caused by the ladder approximation of rectangular ***,three surface boundary models(the underground circular void model,the undulating stratum model,and actual measurement model)are *** comparing reflection waveforms simulated by the traditional Symplectic Euler algorithm,the conformal Symplectic Euler algorithm and the conformal finite difference time domain(CFDTD),the conformal Symplectic Euler algorithm achieves almost the same level of accuracy as the CFDTD method,but the conformal Symplectic Euler algorithm improves the computational efficiency compared with the CFDTD method *** the dielectric constants of the two materials vary greatly,the conformal Symplectic Euler algorithm can reduce the pseudo-waves almost by 80% compared with the traditional Symplectic Euler algorithm on average.

关键词： Symplectic Euler algorithm conformal grid complex geoelectric model ground-penetrating radar pseudo-reflection wave

Quantitative Risk Analysis of a Rainfall-Induced Complex Landslide in Wanzhou County,Three Gorges Reservoir,China

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International Journal of Disaster Risk Science 2020年第3期11卷 347-363页

作者： Lili Xiao Jiajia Wang Yanbo Zhu Jun Zhang School of highway Chang'an UniversityXi'an 710064China School of Geological engineering and Geomatics Chang'an UniversityXi’an 710064China Tunnel and Underground engineering research center of Jiangsu Province Nanjing 210041China

On 4 April 2013,a 1.5 million cubic meter landslide occurred in Sunjia Town,Wanzhou County,Three Gorges Reservoir,*** initiation,the Sunjia landslide traveled about 30 m toward the northeast and destroyed most of the infrastructure in its *** landslide was triggered by heavy rainfall and previous slope excavations,but this slope also displayed a complicated failure process:the overlying earth slope first deformed and then induced sliding along underlying rock *** displacements that resulted from continuous creeping of the post-event slope were observed by an emergency monitoring system that revealed the disequilibrium state of the *** discuss the stability and future movements of the remaining unstable debris deposits,we developed a geotechnical model of the post-slide slope,calculated how it can slide again in an extreme rainfall scenario,and estimated the potential runout distance using the Tsunami Squares *** then estimated the number of people and the value of the infrastructure threatened by this potential ***,we analyzed the vulnerability of elements at risk and quantitatively evaluated the hazard risk associated with the most dangerous *** quantitative risk analysis provides a better understanding of,and technical routes for,hazard mitigation of rainfallinduced complex landslides.

关键词： China Hazard mitigation Quantitative risk analysis Rainfall-induced landslides Runout simulation Slope stability Three Gorges Reservoir

Flow resistance in the channel-bar landscape of large alluvial rivers

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Frontiers of Earth Science 2024年第2期18卷 412-421页

作者： Yong HU Congcong LIU Jinyun DENG Wei ZHANG Yitian LI State Key Laboratory of Water Resources and Hydropower engineering Science Wuhan UniversityWuhan 430072China CCCC Second Harbor engineering Company Ltd Wuhan 430040China Key Laboratory of Large-span Bridge Construction Technology Wuhan 430040China research and Development center of Transport Industry of Intelligent Manufacturing Technologies of Transport infrastructure Wuhan 430040China CCCC highway Bridge National engineering research Centre Co.Ltd Wuhan 430040China

Accurate approaches for estimating flow resistance in large alluvial rivers are fundamental for simulating discharge,sediment transport,and flood ***,methods for estimating riverbed resistance and additional resistance in the channel-bar landscapes remain poorly *** this study,we used in situ river bathymetry,sediment,and hydraulic data from the Shashi Reach in the Yangtze River to develop a semi-empirical approach for calculating flow *** method quantitatively separates flow resistance into riverbed resistance and additional resistance and shows high accuracy in terms of deviation ratio(~20%),root-mean-square error(~0.008),and geometric standard deviation(~3).Additional resistance plays a dominant role under low-flow conditions but a secondary role under high flows,primarily due to the reduction in momentum exchange in channel-bar regions as discharge *** resistance first decreases and then increases,which might be attributed to bedform changes in the lower and transitional flow regimes as flow velocity ***,our findings further the understanding of dynamic changes in flow resistance in the channel-bar landscapes of large river systems and have important implications for riverine ecology and flood management.

关键词： flow resistance channel-bar landscape interaction region large river bedform

CFD Investigations of Interaction Between Freak Wave and Bottom-Mounted Vertical Cylinder

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Journal of Shanghai Jiaotong university(Science) 2024年第5期29卷 809-816页

作者： GAO Ningbo ZHANG Yongtao ZHANG Hong CCCC Second Harbor engineering Co. Ltd.Wuhan430040China Key Laboratory of Large-Span Bridge Construction Technology Wuhan430040China research and Development center of Transport Industry of Intelligent Manufacturing Technologies of Transport infrastructure Wuhan430040China CCCC highway Bridges National engineering research Centre Co. Ltd.Beijing100088China

We studied the interactions between freak wave and bottom-mounted vertical *** freak wave is generated through linear superposition method which satisfies the definition that the wave height is at least two times the significant wave height.A numerical wave tank is developed based on FLUENT software in which the finite volume method is used for the spatial *** sensitivity is conducted in 2D model,and then the freak wave is simulated in 3D *** freak wave loads on the vertical cylinder are calculated and compared with the results obtained through Morison *** numerical results present larger peak and shallower trough compared with the prediction of Morison ***,the free surface wave elevation within a radius distance around the vertical cylinder is *** lowest wave run-up around vertical cylinder caused by freak wave is about 55%of the highest wave run-up,and the direction is about 45°of the wave propagation.

关键词： Navier-Stokes equations freak wave wave run-up wave force

Dynamic Response Solution of Multi-Layered Pavement Structure Under FWD Load Appling the Precise Integration Algorithm

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Computers, Materials & Continua 2019年第6期59卷 853-871页

作者： Zejun Han Hongyuan Fang Juan Zhang Fuming Wang School of Civil engineering and Transportation South China University of TechnologyGuangzhou510640China College of Water Conservancy&Environmental engineering Zhengzhou University.Zhengzhou450001China National Local Joint engineering Laboratory of Major infrastructure Testing and Rehabilitation Technology Zhengzhou450001China Collaborative Innovation center of Water Conservancy and Transportation infrastructure Safety Henan ProvinceZhengzhou450001China CCCC First highway Consultants Co. LTDShanxi ProvinceXi’an710065China

The pavement layered structures are composed of surface layer,road base and multi-layered soil *** can be undermined over time by repeated vehicle *** this study,a hybrid numerical method which can evaluate the displacement responses of pavement structures under dynamic falling weight deflectometer(FWD)*** proposed method consists of two parts:(a)the dynamic stiffness matrices of the points at the surface in the frequency domain which is based on the domain-transformation and dual vector form equation,and(b)interpolates the dynamic stiffness matrices by a continues rational function of *** mixed variables formulation(MVF)can treat multiple degree of freedom systems with considering the coupling term between degree of *** accuracy of the developed method has been demonstrated by comparison between the proposed method and published results from the other *** the proposed method can be applied as a forward calculation technique to emulate the falling weight deflectometer test for multi-layered pavement structures.

关键词： Falling weight deflectometer dynamic stiffness mixed-variable formulation forward calculation model time-domain

Bridge Pressure Flow Scour at Clear Water Threshold Condition

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Transactions of Tianjin University 2009年第2期15卷 79-94页

作者：郭俊克 KERENYI Kornel PAGAN-ORTIZ Jorge E FLORA Kevin Department of Civil engineering University of Nebraska-Lincoln PKI 204D 1110 S 67th ST Omaha NE 68182-0178 USA Office of infrastructure R&D Turner-Fairbank Highway Research Center Federal Highway Administration 6300 Georgetown Pike McLean VA 22101 USA Office of Bridge Technology Federal Highway Administration 1200 New JerSey Avenue SE Washington DC 20590 USA California Department of Transportation (Caltrans) P. O. Box 942873 Sacramento CA 94273-0001 USA

Bridge pressure flow scour at clear water threshold condition is studied theoretically and *** flume experiments reveal that the measured scour profiles under a bridge are more or less 2-dimensional;all the measured scour profiles can be described by two similarity equations,where the horizontal distance is scaled by the deck width while the local scour by the maximum scour depth;the maximum scour position is located just under the bridge about 15% deck width from the downstream deck edge;the scour begins at about one deck width upstream the bridge while the deposition occurs at about 2.5 deck widths downstream the bridge;and the maximum scour depth decreases with increas-ing sediment size,but increases with deck *** theoretical analysis shows that:bridge scour can be divided into three cases,*** unsubmerged,partially submerged,and totally *** downstream unsubmerged flows,the maximum bridge scour depth is an open-channel problem where the conventional methods in terms of critical velocity or bed shear stress can be applied;for partially and totally submerged flows,the equilibrium maximum scour depth can be described by a scour and an inundation similarity number,which has been confirmed by experiments with two decks and two sediment *** application,a design and field evaluation procedure with examples is presented,including the maximum scour depth and scour profile.

关键词： bridge decks bridge design bridge foundations bridge hydraulics bridge inundation bridge scour pressure flows pressure scour submerged flows.

Adaptive Handover Decision Inspired By Biological Mechanism in Vehicle Ad-hoc Networks

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Computers, Materials & Continua 2019年第9期61卷 1117-1128页

作者： Xuting Duan Jingyi Wei Daxin Tian Jianshan Zhou Haiying Xia Xin Li Kunxian Zheng Beijing Advanced Innovation center for Big Data and Brain Computing Beijing100191China Beijing Key Laboratory for Cooperative Vehicle infrastructure Systems&SafetyControl Beijing100191China School of Transportation Science and engineering Beihang UniversityBeijing100191China Department of engineering and Design University of SussexBrightonBN19RHUK research Institute of highway Ministry Transport Beijing100088China Department of Computer Science and Technology Tsinghua UniversityHaidian DistrictBeijing100088China

In vehicle ad-hoc networks(VANETs),the proliferation of wireless communication will give rise to the heterogeneous access environment where network selection becomes *** by the self-adaptive paradigm of cellular attractors,this paper regards an individual communication as a cell,so that we can apply the revised attractor selection model to induce each connected *** at improving the Quality of Service(QoS),we presented the bio-inspired handover decision-making *** addition,we employ the Technique for Order Preference by Similarity to an Ideal Solution(TOPSIS)for any vehicle to choose an access *** paper proposes a novel framework where the bio-inspired mechanism is combined with *** a dynamic and random mobility environment,our method achieves the coordination of performance of heterogeneous networks by guaranteeing the efficient utilization and fair distribution of network resources in a global *** experimental results confirm that the proposed method performs better when compared with conventional schemes.

关键词： Revised attraction selection model TOPSIS VANETs QoS