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FEA-Sketch: flow entries assisted sketch for heavy flow detection in software-defined networking

science China(Information sciences) 2025年第3期68卷 80-94页

作者： Xiaocan WU He HUANG Yang DU Yu-E SUN Yifan HAN School of Computer Science and Technology Soochow University School of Rail Transportation Soochow University

Software-defined networking decouples the control plane from the data plane to enable centralized flow-level network management, while requiring periodically collecting traffic statistics from the data plane to enforce optimal management. As one of the most important traffic measurement tasks, heavy flow detection has received wide attention for its providing fundamental statistics in various practical applications. Existing studies have proposed sketch-based detection solutions to address the mismatch problem between massive traffic and limited high-speed memory resources for measurement in the data plane. However,they overlook the potential of integrating the flow table, where each entry simultaneously enforces forwarding rules for specific flows and records flow statistics into the sketch design, leading to redundant measurement between the flow table and sketch and being unable to utilize their statistics to jointly enhance estimation accuracy. We propose flow entries assisted sketch(FEA-Sketch) in this work, which employs a differentiated flow recording strategy to record flow statistics jointly using the flow table and sketch for memory-efficient and computationally efficient heavy flow detection. We also propose an optimization-based estimation algorithm to accurately recover per-flow sizes for the flows that only have aggregated statistics due to the sharing of entries in the table(or counters in the sketch). We extend the FEA-Sketch to the distributed measurement setting with a hop-based collaborative measurement strategy, which reduces the measurement workload on switches across the network by avoiding redundant measurements. The experimental results on real Internet traces show that the accuracy of heavy flow detection is improved up to 1.95 times, and the bias of flow size estimation is improved up to 2.99 times, demonstrating that integrating flow entries can significantly improve the performance of heavy flow detection.

关键词： software-defined networking traffic measurement heavy flow flow table sketch

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Microstructures and Properties of Modified Magnesium Phosphate Cement Mortar Prepared at Low Temperatures and Subjected to Freeze-Thaw Cycling at Early Ages

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Journal of Wuhan University of technology(Materials science) 2025年第2期40卷 427-438页

作者： YUAN Jie ZHANG Zipeng CHEN Xin HUANG Xin School of Transportation Science and Engineering Harbin Institute of TechnologyHarbin 150090China

Microstructures and properties of mortar using ammonium phosphate and potassium phosphate were tested and compared in this ***,two cementitious additions and two lightweight aggregates,including fly ash,redispersible latex powder,ceramsite sand,and rubber powder,were respectively tried to be applied in magnesium ammonium phosphate cement mortar in order to modify the microstructures and *** experimental results show that potassium phosphate is not suitable for magnesium phosphate cement mortar for cold region construction *** fly ash can bring positive modification in the condition of normal temperature curing,it brings negative effects in the condition of sub-zero temperature *** redispersible latex powder or ceramsite sand can improve the freeze-thaw cycling resistance of magnesium phosphate cement mortar in the conditions of low temperature coupled with freeze-thaw cycling,but only the ceramsite sand can improve both mechanical properties and freeze-thaw cycling *** modification caused by ceramsite sand is mainly due to the exceptional bonding strength between hardened cement paste and the porous surface of ceramsite and the porous structure of ceramsite for the release of frost heave stress.

关键词： magnesium phosphate cement sub-zero temperature freeze-thaw cycling early age

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Study on performance and microscopic mechanism of hydrogen peroxide treated waste crumb rubber modified asphalt

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Journal of Traffic and transportation Engineering(English Edition) 2025年第2期12卷 331-343页

作者： Xinjun Feng Hao Fu Zijian Dai Wang Li School of Transportation Changsha University of Science&TechnologyChangsha 410114China

The application of waste crumb rubber to modified asphalt can not only improve pavement performance,but also make full use of renewable resources,which is of great significance to environmental ***,the waste crumb rubber modified asphalt has some disadvantages such as poor storage stability,high viscosity and high construction temperature requirement,which restricts the application of crumb rubber modified asphalt in road *** order to improve the storage stability and construction workability of waste crumb rubber modified asphalt,in this paper hydrogen peroxide is adopted for the surface oxidation treatment of waste crumb rubber,to prepare five kinds of hydrogen peroxide treated waste crumb rubber modified asphalt with waste crumb rubber dosage of15%,20%,25%,30%,and 35%(wt%).The pavement performance was studied by conventional performance tests and rheological properties ***,the microscopic mechanism was studied by scanning electron microscopy,infrared spectroscopy and thermogravimetric *** results show that the waste crumb rubber becomes fluffy and has a richer pore structure on the surface after hydrogen peroxide treatment,which makes it easier for the light components in the asphalt to penetrate into the waste crumb rubber,and thus promotes its dissolution in asphalt,thereby improving the storage stability,construction workability,and low temperature performance of waste crumb rubber modified asphalt,but reduces the high temperature and elastic *** the same time,the surface polarity of activated waste crumb rubber is enhanced,and esterification reaction occurs with carboxyl groups,sulfoxides and acid anhydrides in asphalt,which effectively increases the interface bonding between asphalt and the waste crumb rubber,and further improves the storage stability,construction workability and low temperature performance of the waste crumb rubber modified *** optimum dosage of waste crumb rubber modified asphalt

关键词： Waste crumb rubber Hydrogen peroxide treatment Modified asphalt Storage stability Microscopic mechanism

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RAP agglomeration and partial blending of recycled hot mix asphalt: A literature review

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Journal of Road Engineering 2025年第2期5卷 230-243页

作者： Xinman Ai Zhongshi Pei Ke Xu Wenyi Zhou Ying Wang Decheng Feng Junyan Yi School of Transportation Science and Engineering Harbin Institute of TechnologyHarbin 150090China

Current mix design practices typically assume total blending and use the white curve of reclaimed asphalt pavement(RAP)to determine the gradation and optimum asphalt content(OAC)of recycled hot mix asphalt(HMA),often overlooking the effects of RAP agglomeration and partial *** oversight can result in unsatisfactory performance,particularly when higher RAP content is ***,this paper reviews and discusses strategies for adjusting the mix design of recycled HMA to enhance its in-service *** discussion begins with RAP particle agglomeration,a significant phenomenon that significantly impacts the aggregate gradation of recycled ***,detection methods to clarify the blending between virgin and RAP binders are *** blending between RAP and virgin binders is common,and various indexes have been proposed to quantify the blending ***,the adjusted mix design method of recycled HMA is presented,emphasizing gradation optimization and corrected *** optimization should account for RAP agglomeration,while the corrected OAC should consider particle *** HMA using the adjusted mix design exhibits improved crack resistance and fatigue life without substantially impairing rutting *** review aims to help both academics and highway agencies maximize the utilization of RAP materials within sustainable pavement frameworks.

关键词： Recycled HMA Adjusted mix design RAP agglomeration Blending between RAP binder and virgin binder Gradation optimization Corrected optimum asphalt content(OAC)

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Research on Cooperative Control Feasibility of Methanol Internal Combustion Engine with Dual Electric Turbo Compound System

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Engineering Letters 2025年第2期33卷 253-264页

作者： Song, Yong Sun, Jianghao Zhang, Xiqing Li, Zhanlong Xu, Tuo Wang, Yao School of Vehicle and Transportation Engineering Taiyuan University of Science and Technology Taiyuan030024 China

To address the problem that cooperative control both power performance and economy of the methanol internal combustion engine (ICE), a dual electric turbo compound (dual-ETC) system is proposed. And the external characteristics of the methanol ICE with the dual-ETC system under typical characteristic speed conditions were investigate. Taking the methanol ICE developed and improved based on a certain type of natural gas ICE as the research object, a one-dimensional thermo-dynamic simulation model is established and calibrated by simulation software GT-Power. The speed influences of the turbine and the compressor on the main performance parameters of the methanol ICE are studied. It is found that the turbine speeds of the dual-ETC system have little influences on the main performance parameters, whereas the compressor speeds exert more significant influences. Additionally, the turbine efficiencies demonstrate a trend of initially increasing and then decreasing as turbine speed rises. For the external characteristics of the methanol ICE with the dual-ETC system, it is found that the torque increase and the torque increase rate are larger, and the economy and the power performance are better under the maximum speed condition of the compressor at the upper and the lower boundary speeds of the peak net torque range. Compared to the comparison engine, by adjusting the compressor speed, the power performance at the low speed (the torque increases by about 7.24%) and the economy at the high speed (the comprehensive fuel consumption decreases by about 6.26 kg/h) are increased. These findings suggest the possible approach for the cooperative control of the external characteristics of the methanol ICE with the dual-ETC system. The above research results verify the correctness and the effectiveness of the proposed system, and the cooperative control feasibility of methanol ICE with dual-ETC system. © 2025, International Association of Engineers. All rights reserved.

关键词： Internal combustion engines

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Research on Hybrid Control Methods for the Path Tracking of Driverless Vehicles

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Engineering Letters 2025年第2期33卷 476-489页

作者： Li, Jingyuan Xi, Jianguo Xie, Chengwei Gao, Jianping School of Vehicle and Transportation Engineering Henan University of Science and Technology Luoyang471000 China

This paper presents a hybrid control strategy that utilizes fuzzy control theory to tackle the issue of suboptimal path tracking performance in autonomous vehicles operating at different speeds. The proposed method integrates an enhanced pure pursuit control approach, with a model predictive control strategy rooted in vehicle dynamics. The method selects different control algorithms depending on the vehicle's speed range, optimizing path tracking performance across different operational conditions. Simulations conducted using the Carsim/Simulink platform demonstrate that, under double-shifted line condition, the peak lateral error is diminished by 18.5%, and the maximum front wheel angle is diminished by 12.3%. In lane-changing curve condition, the peak lateral error is diminished by 17.8%, and the highest front wheel angle is decreased by 17.3%. Under continuous lane-changing curve condition, the peak lateral error decreases by 18.4%, and the peak front wheel angle is reduced by 20%. The experimental findings validate that the proposed hybrid control approach considerably enhances both path tracking precision and vehicle stability under various driving conditions. © 2025, International Association of Engineers. All rights reserved.

关键词： Predictive control systems

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Vehicle Height Control of Active Hydropneumatic Suspension Considering Ride Comfort

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IAENG International Journal of Applied Mathematics 2025年第4期55卷 861-867页

作者： Duan, Yizhuang Dong, Zhenle Bai, Dongjie Zhou, Zhigang Li, Geqiang Wang, Shuai School of Vehicle and Transportation Engineering Henan University of Science and Technology Luoyang471000 China School of Mechatronics Engineering Henan University of Science and Technology Luoyang471000 China

Active hydro-pneumatic suspension has been widely used in heavy vehicles for its extraordinary merits, such as non-linear stiffness and damping, adjustable body height, etc. This paper proposes a vehicle height control method for active hydro-pneumatic suspension considering ride-comfort, a mathematical model of the hydro-pneumatic suspension integrating the dynamics of gas spring (accumulator) and valve-controlled hydraulic system is established, and the control strategy containing model compensation and robust feedback is designed based on backstepping, and the stability of the system is proved via Lyapunov analysis, which shows that the proposed control strategy can theoretically realize the accurate control of vehicle height and limit the acceleration amplitude of the frame. The MATLAB/Simulink platform is used for simulation. The simulation results under the two working conditions show that compared with PID control, the proposed control strategy can achieve higher vehicle height adjustment accuracy and improve vehicle ride comfort. © 2025 IAENG International Journal of Applied Mathematics

关键词： Backstepping

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A Diffusion Model for Traffic Data Imputation

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IEEE/CAA Journal of Automatica Sinica 2025年第3期12卷 606-617页

作者： Bo Lu Qinghai Miao Yahui Liu Tariku Sinshaw Tamir Hongxia Zhao Xiqiao Zhang Yisheng Lv Fei-Yue Wang the School of Artificial Intelligence University of Chinese Academy of Sciences Baidu Inc. IEEE the State Key Laboratory for Multimodal Artificial Intelligence Systems Institute of Automation Chinese Academy of Sciences Meituan Guangdong University of Technology the Department of Transportation Engineering School of Transportation Science and Technology Harbin Institute of Technology

Imputation of missing data has long been an important topic and an essential application for intelligent transportation systems(ITS) in the real world. As a state-of-the-art generative model, the diffusion model has proven highly successful in image generation, speech generation, time series modelling *** now opens a new avenue for traffic data imputation. In this paper, we propose a conditional diffusion model, called the implicit-explicit diffusion model, for traffic data imputation. This model exploits both the implicit and explicit feature of the data simultaneously. More specifically, we design two types of feature extraction modules, one to capture the implicit dependencies hidden in the raw data at multiple time scales and the other to obtain the long-term temporal dependencies of the time series. This approach not only inherits the advantages of the diffusion model for estimating missing data, but also takes into account the multiscale correlation inherent in traffic data. To illustrate the performance of the model, extensive experiments are conducted on three real-world time series datasets using different missing *** experimental results demonstrate that the model improves imputation accuracy and generalization capability.

关键词： Data imputation diffusion model implicit feature time series traffic data

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High-Superelasticity NiTi Shape Memory Alloy by Directed Energy Deposition-Arc and Solution Heat Treatment

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Acta Metallurgica Sinica(English Letters) 2024年第1期37卷 132-144页

作者： Junyi Ma Lin Yu Qing Yang Jie Liu Lei Yang State Key Laboratory of Materials Processing and Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan430070China School of Transportation and Logistics Engineering Wuhan University of TechnologyWuhan430074China

Directed energy deposition-arc(DED-Arc)technology has the advantages of simple equipment,low manufacturing cost and high deposition rate,while the use of DED-Arc has problems of microstructure inhomogeneity,position dependence of macroscopic mechanical properties and ***,it is necessary to carry out a subsequent heat treatment to improve its microstructure uniformity,mechanical properties and *** this investigation,the DED-Arc 15-layer NiTi alloy thin-walled parts with the solution treatment at different process parameters were studied to analyze the effects of solution heat treatment on microstructure,phase composition,phase transformation,microhardness,tensile and *** temperature range of solution treatment is 800-1050℃,and the treatment time range is 1-5.5 *** results show that after solution treatment at 800℃/1 h,the content of precipitated phase decreases,the grain is refined,the microhardness increases,and the mechanical properties in the 0°direction are *** strain recovery rate after 10 tensile cycles has increased from 37.13%(as-built)to 49.25%(solid solution treatment).This research provides an effective post treatment method for high-performance DED-Arc NiTi shape memory alloys.

关键词： Directed energy deposition-arc(DED-Arc) Cold metal transfer(CMT) NiTi shape memory alloys Microstructure Phase transformation Solution heat treatment

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Impacts of bus holding strategy on the performance and pollutant emissions of a two-lane mixed traffic system

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Chinese Physics B 2024年第11期33卷 236-248页

作者： Yanfeng Qiao Ronghan Yao Baofeng Pan Yu Xue School of Infrastructure Engineering Dalian University of TechnologyDalian 116024China School of Transportation and Vehicle Engineering Shandong University of TechnologyZibo 255049China School of Physical Science and Technology Guangxi UniversityNanning 530004China

This paper investigates the impacts of a bus holding strategy on the mutual interference between buses and passenger cars in a non-dedicated bus route,as well as the impacts on the characteristics of pollutant emissions of passenger *** dynamic behaviors of these two types of vehicles are described using cellular automata(CA)models under open boundary *** simulations are carried out to obtain the phase diagrams of the bus system and the trajectories of buses and passenger cars before and after the implementation of the bus holding strategy under different probabilities of passenger cars entering a two-lane mixed traffic ***,we analyze the flow rate,satisfaction rate,and pollutant emission rates of passenger cars together with the performance of a mixed traffic *** results show that the bus holding strategy can effectively alleviate bus bunching,whereas it has no significant impact on the flow rate and pollutant emission rates of passenger cars;the flow rate,satisfaction rate,and pollutant emission rates of passenger cars for either the traffic system or for each lane are influenced by the bus departure interval and the number of passengers arriving at bus stops.

关键词： mixed traffic flow bus holding strategy cellular automata traffic emissions

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