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Traffic replay can effectively improve the fidelity of network emulation and support emerging network verification and network security evaluation. A distributed traffic replay system based on cloud platform is designed for large-scale, high-speed and highly concurrent network traffic emulation, named DTRS. Aiming at the diverse network traffic, a scalable multi-stream replay method is proposed to realize the flexible reproduction of multiple protocol traffic. A traffic replay strategy based on DPDK is proposed to achieve accurate control of the replay process and improve the timing fidelity of replay. To solve the problem of insufficient traffic replay speed, a vector packet processing strategy based on VPP is proposed to improve the throughput. The experimental results show that DTRS can realize the scalable loading of diverse network traffic, and support the flexible, realistic and controllable reproduction of massive heterogeneous network scenarios. In high- speed traffic emulation, DTRS can ensure the timing fidelity of replay. Compared with traditional methods, the traffic replay throughput of DTRS has increased by 3.71 times. [ABSTRACT FROM AUTHOR]

Copyright of Railway Construction Technology is the property of Railway Construction Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Chongqing University of Technology (Natural Science) is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Computer Engineering & Applications is the property of Beijing Journal of Computer Engineering & Applications Journal Co Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of South China University of Technology (Natural Science Edition) is the property of South China University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The problem of ineffective coordination between adjacent intersections of urban trunk roads due to the lack of information interaction, which leads to inefficient operation of trunk roads, this paper proposed a multi-objective collaborative optimization model of adjacent intersections of urban trunk roads under V2 X environment. The entry point was to obtain traffic volume and speed characteristics in real-time with V2 X technology. This paper took the traffic load as the key parameter. Weighting measurement based on different lane functions. At the same time, this paper introduced comfort and travel time as the synergistic regional optimization parameters, and used their weighted amounts as the comprehensive evaluation indexes of the model. Then this paper constructed a multi-objective collaborative optimization model for adjacent intersections of urban trunk roads. Finally, in order to verify the effectiveness of the model, using the NSGA-II algorithm simulated the examples to obtain the Pareto frontier of the optimization objective. The analysis results show that: The combined traffic load of key areas is reduced by about 19.9%, and the speed variation rate of synergistic regional trunk road traffic is reduced by about 28.37% and the travel time is reduced by about 3.46%, which can effectively improve the efficiency of urban trunk road traffic. [ABSTRACT FROM AUTHOR]

Copyright of Experimental Technology & Management is the property of Experimental Technology & Management Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To solve the car-following problem of intelligent and connected vehicle (ICV), a car-following model of ICV was proposed, and the model properties were analyzed. Considering the car-following property of variable headway, the ICV car-following model was proposed to maintain simple model structure and clear physical meaning of model parameters. Based on the function of spacing and speed at equilibrium state, the flow-density function curve of the proposed ICV car-following model was calculated. The mechanism of improving traffic capacity by the proposed ICV car-following model was also analyzed. From the perspective of microcosmic kinematics, the stability criterion of the proposed ICV car-following model was theoretically derived. The results show that according to the proposed ICV carfollowing model, the maximum capacity can be obtained with the density of 66. 887 2 car · km -1 and the speed of 63. 576 0 km ·h -1. The model stability criterion is related with traffic flow speed and can be stable at any speed, which shows that the model has good model stability condition. [ABSTRACT FROM AUTHOR]

Copyright of Railway Signalling & Communication Engineering is the property of Railway Signalling & Communication Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Beijing University of Technology is the property of Journal of Beijing University of Technology, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Railway Investigation & Surveying is the property of Railway Investigation & Surveying Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Telecommunication Engineering is the property of Telecommunication Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Tracked undercarriage is considered as a technical solution to reduce the soil compaction as compared to the tire due to its large contact area between track and soil. However, the interaction between track and soil is complex, resulting in uneven distributed stress at track/soil interface. Uneven distributed stress may reduce the ability that track decreases the soil compaction and will also lead to the increases of track sinkage depth, which may reduce the vehicle's traffic-ability. Therefore, we can better understanding of the soil compaction process with the help of investigating the distribution of soil stress beneath the tracked undercarriage. The objectives of this study were to estimate the distribution of soil vertical and horizontal stresses under the tracked undercarriage in the track length direction, and to investigate the effect of track tensions on the distribution of soil stress. The test was conducted on the sandy loam soil and combine harvester equipped with rubber tracks was used in the test. The rubber tracked undercarriage system is comprised of a front wheel and a rear wheel with two support wheels. During measurement, the harvester was unloaded and without its header. The soil stress was measured by embedding the pressure sensors under the centerline of the track at depth of 0.35m. In total four pressure sensors were installed: two sensors for vertical stress, and two sensors for horizontal stress (piston facing the vehicle’s driving direction). A laser position sensor fixed on the ground was employed to track the positions of the axle of track wheels. Three repeated measurements were performed with different track tensions (i.e. 1.6×104, 1.7×104, and 1.8×104 kPa) at same traffic speed. The results showed that the measured vertical stress presented three peak points along the track length, with two peaks beneath each axle of track drive wheel and guide wheel, and one peak between two support wheels. The horizontal stress presented two peaks before and after each wheel axle, with the minimum stress on the axle. Moreover, the magnitude of soil stress beneath each of track wheel were different, with the largest vertical stress beneath the guide wheel, and the largest horizontal stress between guide wheel and rear support wheel. The maximum stress and mean maximum stress under the track were decreased with the decreasing of track tension, when the track tension was reduced from 1.8 × 104 kPa to 1.6 × 104 kPa, the maximum vertical and horizontal stresses were reduced by 37.3% and 21.7% respectively, and the mean maximum vertical and horizontal stresses were reduced by 26.4% and 20.4% respectively, which indicated that decreasing the track tension could improve the uniformity of the soil stress. However, too small track tension will lead to relaxation of track, resulting in track failure and affecting the ride comfort of the vehicle. Therefore, it has limitations in improving the uniformity of stress by reducing track tension. Some other methods, such as optimizing the configuration of track wheels along the track length, may also improve the uniformity of the soil stress under the tracked undercarriage. More investigation about the effect of track wheel configuration on the soil stress distribution is needed in the future work. This study can provide preliminary guidance on optimizing the structure of tracked undercarriage to improve the uniformity of soil stress. [ABSTRACT FROM AUTHOR]

Aiming at the problem that the existing traffic flow velocity prediction model used a unique data set and a single model, this paper proposed a prediction model combining time series and artificial neural network. The model predicted real-time data and historical data by time series, and used artificial neural network to adjust the predicted values of real-time data and historical data. The experimental results show that the prediction model can control the prediction error within 7 % and can effectively predict the short-term traffic flow speed under different input parameters. [ABSTRACT FROM AUTHOR]

Based on the powerful nonlinear mapping ability of kernel learning, this paper proposed a class of kernel learning method for the short-term traffic flow forecasting. Kernel recursive least squares( KRLS) method using approximate linear dependence( ALD) technique could reduce the computational complexity and storage capacity, the KRLS method was an online kernel learning method and was suitable for training on large-scale data sets. Kernel partial least square( KPLS) method utilized the covariance between input and output variables to extract latent features. Kernel extreme learning machine( KELM)method used the kernel function to substitute for the unknown nonlinear feature mapping of the hidden layer, in addition, the output weights of the networks could also be analytically determined by using regularization least square algorithm, hence KELM method provided better generalization performance at a much faster learning speed. In order to verify the validity of the proposed kernel learning method, this paper respectively applied the employed KELM, KPLS and ALD-KRLS methods to different traffic flow forecasting instances in different area, compared to the other methods under the same conditions. Experimental results show that the proposed kernel-based learning methods have higher forecasting accuracy and improves training speed in the short-term traffic flow forecasting. [ABSTRACT FROM AUTHOR]

To clear the best limiting speed strategy in urban expressway ramp merging area, based on the principle of limiting speed on ramp merging area, the effects of speed distribution, relationship between volume and speed, speed distribution in various lane position, vehicle type and lane width on the appropriate speed of ramp vehicles were studied by actual measured data of expressway and mathematical statistics. The result shows that the speed from inside to outside is decreased, and mainly affected by the traffic flow. Traffic speed characteristics are different between ramp merging area and basic road section, and different speed limit strategy should be formulated, the value should be determined according to the location of lanes, lane width and traffic situation integrated. [ABSTRACT FROM AUTHOR]

In order to reduce the conflict between right -- turn vehicles and through bicycles, o enhance the operational efficiency, we analyze the conflict mechanism between right -- turn vehicles and through bicycles and running characteristics of bicycles on two -- phase intersection, and determine the critical value of through bicycle flow for setting right -- turn vehicle signal. For the sake of reducing the conflict and enhancing the intersectional operational efficiency, we determine the start -- up of green time and its length, and then establish a relevant model of parameters demarcated. Based on collected data in field, the simulated verification is completed by VISSIM. The results indicate that the delay of right -- turn vehicles and the conflict are reduced obviously. [ABSTRACT FROM AUTHOR]