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CPSO-XGBoost segmented regression model for asphalt pavement deflection basin area prediction

science China(Technological sciences) 2022年第7期65卷 1470-1481页

作者： LI ZhuoXuan SHI XinLi CAO JinDe WANG XuDong HUANG Wei School of Mathematics Southeast UniversityNanjing 210096China School of Cyber Science&Engineering Southeast UniversityNanjing 210096China Yonsei Frontier Lab Yonsei UniversitySeoul 120-749Korea Research Institute of Highway Ministry of TransportBeijing 100088China Intelligent Transportation System Research Center Southeast UniversityNanjing 210096China

The use of non-destructive testing(NDT) equipment, such as the falling weight deflectometer(FWD), provides important estimates of road health and helps to optimize road management regimes. However, periodic road testing and post-processing of the collected data are cumbersome and require much expertise, a considerable amount of time, money, and other resources. This study attempts to develop a reliable prediction method for estimating the deflection basin area of different asphalt pavements using road temperature, load time, and load pressure as main characteristics. The data are obtained from 19 kinds of asphalt pavements on a 2.038-km-long full-scale fleld accelerated pavement testing track named RIOHTrack(Research institute of Highway Track) in Tongzhou, Beijing. In addition, a chaotic particle swarm algorithm(CPSO) and a segmented regression strategy are proposed in this paper to optimize the XGBoost model. The experiment results of the proposed method are compared with those of classical machine learning algorithms and achieve an average of mean square error and mean absolute error respectively by 5.80 and *** experiments demonstrate the superiority of the XGBoost algorithm over classical machine learning methods in dealing with nonlinear problems in road engineering. Signiflcantly, the method can reduce the frequency of deflection tests without affecting its estimation accuracy, which is a promising alternative way to facilitate the rapid assessment of pavement conditions.

关键词： FWD pavement management systems RIOHTrack deflection basin area CPSO XGBoost segmented regression model

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A Dynamic Load Balancing Algorithm for Stable Pushing of Docker Images in Nginx 6

A Dynamic Load Balancing Algorithm for Stable Pushing of Doc...

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6th International Conference on Machine Learning, Big Data and Business Intelligence, MLBDBI 2024

作者： Xi, Hajie Hu, Song Zhang, He Zhang, Shuang Weng, Jingnong Huang, Jian School of Computer Science and Engineering Beihang University Beijing China Research Institute of Highway Ministry of Transport State Key Lab of Transportation System Beijing China Transportation Comprehensive Enforcement Corps Beijing China School of Software Beihang University Beijing China

ISBN: (纸本)9798331541798

With the rapid development of artificial intelligence, a wide variety of deep learning models have emerged across various fields. Nevertheless, the quality of these models varies significantly, making the effective evaluation of model performance a pressing issue. In some open data competitions, remote evaluation based on Docker images has increasingly become a novel and reliable approach, providing a consistent environment to ensure the fairness of model evaluations. However, it imposes high demands on hardware resources, typically requiring dedicated resources for each participant to serve as Docker Registries for the pushing and management of Docker images. In this paper, we extend the load balancing module of the Nginx server by integrating Lua scripts and propose a Cache-based Dynamic Smooth Weighted Round-robin (CDSWRR) algorithm to optimize the pushing process of Docker images. By constructing a unified load balancing entry, the proposed approach simplifies the deployment of Docker Registry clusters. Experiments show that compared to weighted round-robin and IP hash algorithms of Nginx, the CDSWRR algorithm is able to ensure stable pushing of Docker images and reduce both response error rate and response time. © 2024 IEEE.

关键词： Deep learning

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Development of database of real-world diesel vehicle emission factors for China

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Journal of Environmental sciences 2015年第5期27卷 209-220页

作者： Xianbao Shen Zhiliang Yao Qiang Zhang David Vance Wagner Hong Huo Yingzhi Zhang Bo Zheng Kebin He State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University School of Food and Chemical Engineering Beijing Technology and Business University Ministry of Education Key Laboratory for Earth System Modeling Center for Earth System Science Tsinghua University International Council on Clean Transportation (ICCT) Institute of Energy Environment and Economy Tsinghua University State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex Tsinghua University

A database of real-world diesel vehicle emission factors, based on type and technology, has been developed following tests on more than 300 diesel vehicles in China using a portable emission measurement system. The database provides better understanding of diesel vehicle emissions under actual driving conditions. We found that although new regulations have reduced real-world emission levels of diesel trucks and buses significantly for most pollutants in China, NOx emissions have been inadequately controlled by the current standards, especially for diesel buses, because of bad driving conditions in the real world. We also compared the emission factors in the database with those calculated by emission factor models and used in inventory studies. The emission factors derived from COPERT（Computer Programmer to calculate Emissions from Road Transport） and MOBILE may both underestimate real emission factors, whereas the updated COPERT and PART5（Highway Vehicle Particulate Emission Modeling Software） models may overestimate emission factors in China. Real-world measurement results and emission factors used in recent emission inventory studies are inconsistent,which has led to inaccurate estimates of emissions from diesel trucks and buses over recent years. This suggests that emission factors derived from European or US-based models will not truly represent real-world emissions in China. Therefore, it is useful and necessary to conduct systematic real-world measurements of vehicle emissions in China in order to obtain the optimum inputs for emission inventory models.

关键词： Diesel vehicle Emission factor Portable emission measurement system Database China

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Synthesis and Performance Characterization of a Low Adsorption Clay-resistant Polycarboxylate Superplasticizer

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Journal of Wuhan University of Technology(Materials science) 2021年第3期36卷 446-455页

作者： ZHANG Ying WANG Pengshuo SUN Guowen YANG Jianming GAO Rui School of Materials Science and Engineering Shijiazhuang Tiedao UniversityShijiazhuang 050043China College of Civil Engineer-ing Yancheng Institute of TechnologyYancheng 224051China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang050043China Heibei Key Laboratory of Advanced Materials for Transportation Engineering and Environment Shijiazhuang Tiedao UniversityShijiazhuang050043China

A low adsorption clay-resistant polycarboxylate superplasticizer(KN-PC)was synthesized using acrylic acid and isopentenol polyoxyethylene ether as the main reaction *** structural characterization and clay-resistant mechanism of the KN-PC were explored using Fourier transform infrared spectroscopy and X-ray diffraction,and the effect of the KN-PC on the performance of composite paste with various montmorillonite(MMT)contents was *** with ordinary polycarboxylate superplasticizer(PC),the KN-PC has a low sensitivity to the *** the action of the MMT,the adsorption dosage of the KN-PC on the MMT is much smaller than that of the PC.

关键词： polycarboxylate superplasticizer clay-resistant montmorillonite performance synthesis

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RESEARCH ON THE OVERALL DESIGN OF A HIGH-SPEED MORPHING UAV 33

RESEARCH ON THE OVERALL DESIGN OF A HIGH-SPEED MORPHING UAV

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33rd Congress of the International Council of the Aeronautical sciences, ICAS 2022

作者： Ding, Chao Ma, Tielin Fu, Jingcheng Wang, Xiangsheng School of Aeronautic Science and Engineering Beihang University Beijing100191 China Key Laboratory of Advanced Technology of Intelligent Unmanned Flight System Ministry of Industry and Information Technology Beijing100191 China Institute of Unmanned System Beihang University Beijing100191 China School of Transportation Science and Engineering Beihang University Beijing100191 China

ISBN: (纸本)9781713871163

Due to its broad application prospects in the military and civilian fields, air-launch high-speed aircraft is an important direction for the development of high-speed aircraft in the future. However, air-launch supersonic vehicles face the characteristics of limited volume, small lift-to-drag ratio, difficult trimming, and poor handling characteristics. A supersonic vehicle with morphing wing can flexibly change its aerodynamic shape according to different flight environments, which can improve the weakness of supersonic flight. This paper takes the air-launch high-speed aircraft with the outer wing folded as the research object and carries out the overall design research according to the proposed task requirements. The tailless aerodynamic layout combined with the strake wing and the multi-section swept wing was proposed. Aiming at the difficult problem of longitudinal moment trimming, a combined analysis method of pressure center position and pressure map is proposed. The research results show that the aircraft designed in this study has good aerodynamic performance in different speed domains, and it can maintain the longitudinal moment trim at the cruise angle of attack(AOA). © 2022 ICAS. All Rights Reserved.

关键词： Angle of attack

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Fairness in online vehicle-cargo matching: An intuitionistic fuzzy set theory and tripartite evolutionary game approach

arXiv

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arXiv 2023年

作者： Yang, Binzhou Han, Ke Tu, Wenrui Ge, Qian Institute of System Science and Engineering School of Transportation and Logistics Southwest Jiaotong University China

This paper explores the concept of fairness and equitable matching in an on-line vehicle-cargo matching setting, addressing the varying degrees of satisfaction experienced by shippers and carriers. Relevant indicators for shippers and carriers in the on-line matching process are categorized as attributes, expectations, and reliability, which are subsequent quantified to form satisfaction indicators. Employing the intuitionistic fuzzy set theory, we devise a transformed vehicle-cargo matching optimization model by combining the fuzzy set’s membership, non-membership, and uncertainty information. Through an adaptive interactive algorithm, the matching scheme with fairness concerns is solved using CPLEX. The effectiveness of the proposed matching mechanism in securing high levels of satisfaction is established by comparison with three benchmark methods. To further investigate the impact of considering fairness in vehicle-cargo matching, a shipper-carrier-platform tripartite evolutionary game framework is developed under the waiting response time cost (WRTC) sharing mechanism. Simulation results show that with fairness concerns in vehicle-cargo matching, all stakeholders are better off: The platform achieves positive revenue growth, and shippers and carriers receive positive subsidy. This study offers both theoretical insights and practical guidance for the long-term and stable operation of the on-line freight stowage industry. Copyright © 2023, The Authors. All rights reserved.

关键词： Fuzzy set theory

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L1 augmentations for a fixed gain controller on a large transport aircraft

L1 augmentations for a fixed gain controller on a large tran...

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AIAA Guidance, Navigation, and Control Conference, 2017

作者： Wang, Mengmeng Zhang, Shuguang Holzapfel, Florian Hong, Haichao School of Transportation Science and Technology Beihang University Beijing100191 China Technische Universität München Institute for Flight System Dynamics Garching85748 Germany School of Aerospace Engineering Beijing Institute of Technology Beijing100181 China

ISBN: (数字)9781624104503

ISBN: (纸本)9781624104503

This paper presents a sequential synthesis controller design process, integrating quantitative feedback theory and L1piecewise constant output-feedback control theory. Quantitative Feedback Technique is used to generate a baseline fixed gain controller, to avoid velocity or dynamic pressure based gain scheduling and provide satisfying performance under nominal conditions. In case of off-nominal conditions, the baseline controller is augmented by L1piecewise constant output-feedback control laws. Both baseline plant augmentation and the closed-loop augmentation are introduced to eliminate the performance degradation caused by a off-normal dynamics, such as a pitch-up nonlinearity. These two augmentation strategies are compared regarding performance metrics and robust metrics along the entire envelope. Furthermore, actuator dynamics and time delays are taking into account. © 2017, American institute of Aeronautics and Astronautics. All rights reserved.

关键词： Controllers

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Technologies and studies of gas exchange in two-stroke aircraft piston engine:A review

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Chinese Journal of Aeronautics 2024年第1期37卷 24-50页

作者： Yu ZHOU Xueyu LI Shuiting DING Shuai ZHAO Kun ZHU Longtao SHAO Farong DU Gerui WANG Zheng XU Research Institute of Aero-Engine Beihang UniversityBeijing 100191China Aircraft/Engine Integrated System Safety Beijing Key Laboratory Beijing 100191China School of Transportation Science and Engineering Beihang UniversityBeijing 100191China Civil Aviation University of China Tianjin 300300China Aero Engine Academy of China Beijing 101304China School of Energy and Power Engineering Beihang UniversityBeijing 100191China Beihang Hangzhou Innovation Institute Yuhang Hangzhou 310052China

The in-cylinder gas exchange process is crucial to the power performance of two-stroke aircraft piston engines,which is easily influenced by complex factors such as high-altitude performance variation and in-cylinder flow *** paper reviews the development history and characteristics of gas exchange types,as well as the current state of theory and the validation methods of gas exchange technology,while also discusses the trends of cutting-edge technologies in the *** paper provides a theoretical foundation for the optimization and engineering design of gas exchange systems and,more importantly,points out that the innovation of gas exchange types,the modification of theoretical models,and the technology of variable airflow organization are the key future research directions in this field.

关键词： Aircraft piston engine Aircraft power systems Gas exchange High-altitude performance In-cylinder flow Two-stroke Unmanned Aerial Vehicles(UAVs)

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A comprehensive aerodynamic-thermalmechanical design method for fast response turbocharger applied in aviation piston engines

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Propulsion and Power Research 2024年第2期13卷 145-165页

作者： Yu Zhou Yue Song Shuai Zhao Xueyu Li Longtao Shao Huansong Yan Zheng Xu Shuiting Ding Research Institute of Aero-Engine Beihang UniversityBeijing 100083China Aircraft/Engine Integrated System Safety Beijing Key Laboratory Beijing 100083China School of Energy and Power Engineering Beihang UniversityBeijing 100083China School of Transportation Science and Engineering Beihang UniversityBeijing 100083China AVIC Nanjing Engineering Institute of Aircraft Systems Nanjing 210000China Hangzhou International Innovation Institute Beihang UniversityHangzhou 311115China Civil Aviation University of China Tianjin 300300China

Limited by the poor transient response performance of turbochargers,the dynamic performance of aviation piston engines tends to *** a bid to enhance the turbocharger’s acceleration capabilities,this study scrutinizes various factors impacting its *** on the operational principles and transient response process of the turbocharger,three types of in-ertiadnamely,aerodynamic inertia(ADI),thermal inertia(TI),and mechanical inertia(MI)d are identified and addressed for *** begin,this paper pioneers the innovative definition of a method for evaluating the transient response performance of the *** method incor-porates the introduction of an ADI parameter,inspired by the definition of ***,a thin-walled volute design with a low Biot number and a lightweight turbine impeller is introduced to reduce the turbocharger’s TI and *** simulation results of theflowfield distribution within the volute and diffuser demonstrate the comprehensive design method’s effectiveness in improving gas pressure and temperature distributions in these ***,the pressure distributionfluctuation in the constant moment-of-momentum volute(CMV)is 62.8%lower than that in the constant velocity moment volute(CVMV).The low-TI thin-walled volute not only en-hances the turbocharger’s response speed but also reduces its weight by approximately 40%.The impact of three types of inertia on the engine’s response speed is quantified as follows:ADI(94%)>MI(5%)>TI(1%).This conclusion has been verified through test results of both the turbocharger and the *** design method not only significantly improves the turbo-charger’s response performance but also offers valuable insights for the optimal design of other blade mechanical systems.

关键词： Turbocharger Fast response design method Aerodynamic inertia Thermal inertia Mechanical inertia

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Cooperative Local Path Planning for Multi-unmanned Vehicles Formation Using the Enhanced Artificial Potential Field 3rd

Cooperative Local Path Planning for Multi-unmanned Vehicles...

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3rd International Conference on Autonomous Unmanned systems, ICAUS 2023

作者： Zhang, Xin Duan, Xuting Zhou, Jianshan Zhang, Long Opening Project of Key Laboratory of Operation Safety Technology on Transport Vehicles Ministry of Transport PRC Beijing China School of Transportation Science and Engineering Beihang University Beijing China State Key Lab of Intelligent Transportation System Beijing China Beijing Key Laboratory for Cooperative Vehicle Infrastructure Systems and Safety Control Beijing China Zhongguancun Laboratory Beijing China National Key Laboratory of Science and Technology on Information System Security Institute of Systems Engineering Beijing China

ISBN: (纸本)9789819711024

An enhanced approach utilizing APF(artificial potential field) method is introduced in this paper. By adopting this approach, the challenge of local minima that may occur when dealing with local path planning for unmanned vehicles is tackled. When the unmanned vehicle approaches an obstacle, a virtual attractive potential field is implemented, utilizing the deviation in the heading angle of the vehicle to control the steering angle. Consequently, the vehicle can avoid obstacles, resolving the issue of local minima and enabling its application in path planning for multi-unmanned vehicles. The ROS with Gazebo simulation platform is used to verify the enhanced algorithm’s effectiveness in multi-unmanned vehicle path planning in an unknown environment. © Beijing HIWING Scientific and Technological Information institute 2024.

关键词： Motion planning

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