scholarly journals Dynamic Shaping Method using SDN And NFV Paradigms

2021 ◽  
Vol 13 (2) ◽  
pp. 1-14
Author(s):  
Shin-ichi Kuribayashi
Keyword(s):  
Traffic Flow ◽  
Processing Capacity ◽  
Traffic Data ◽  
System Configuration ◽  
Traffic Shaping ◽  
Optimal Point ◽  
Network Functions ◽  
Communication Flow ◽  
Communication Traffic ◽  
Sdn Controller

Traffic shaping controls communication traffic flow to prevent a specified communication rate from being exceeded. In conventional networks, the traffic shaping device is implemented at a predetermined location and only a communication flow passing through the device is targeted. If the traffic can be shaped dynamically on any selected communication flows at the optimal point only when necessary, it could use network bandwidths and packet relay processing capacity more efficiently and flexibly. This paper proposes a dynamic shaping method using Software-Defined Networking (SDN) and Network Functions Virtualization (NFV) paradigms, which selects the optimal communication flows to be shaped, and the optimal shaping points dynamically. This paper also presented system configuration and functions for the proposed dynamic shaping, and the method to simplify the process of collecting the traffic data of each communication flow by SDN controller.

Impact of Rainfall Condition on Traffic Flow and Speed: A Case Study in Johor and Terengganu

2014 ◽  
Vol 70 (4) ◽  
Author(s):  
Nordiana Mashros ◽  
Johnnie Ben- Edigbe ◽  
Sitti Asmah Hassan ◽  
Norhidayah Abdul Hassan ◽  
Nor Zurairahetty Mohd Yunus
Keyword(s):  
Traffic Flow ◽  
Monsoon Season ◽  
Flow Speed ◽  
Free Flow ◽  
Road User ◽  
Traffic Data ◽  
Average Volume ◽  
Rainfall Condition ◽  
Free Flow Speed ◽  
The Impact

This paper explores the impact of various rainfall conditions on traffic flow and speed at selected location in Terengganu and Johor using data collected on two-lane highway. The study aims to quantify the effect of rainfall on average volume, capacity, mean speed, free-flow speed and speed at capacity. This study is important to come out with recommendation for managing traffic under rainfall condition. Traffic data were generated using automatic traffic counters for about three months during the monsoon season. Rainfall data were obtained from nearest surface rain gauge station. Detailed vehicular information logged by the counters were retrieved and processed into dry and various rainfall conditions. Only daylight traffic data have been used in this paper. The effect of rain on traffic flow and speed for each condition were then analysed separately and compared. The results indicated that average volumes shows no pronounce effect under rainfall condition compared to those under dry condition. Other parameters, however, show a decrease under rainfall condition. Capacity dropped by 2-32%, mean speed, free-flow speed and speed at capacity reduced by 3-14%, 1-14% and 3-17%, respectively. The paper recommends that findings from the study can be incorporated with variable message sign, local radio and television, and variable speed limit sign which should help traffic management to provide safer and more proactive driving experiences to the road user. The paper concluded that rainfall irrespective of their intensities have impact on traffic flow and speed except average volume.

Development of Multiregime Speed–Density Relationships by Cluster Analysis

2005 ◽  
Vol 1934 (1) ◽  
pp. 64-71 ◽  
Author(s):  
Lu Sun ◽  
Jie Zhou
Keyword(s):  
Cluster Analysis ◽  
Traffic Flow ◽  
Ad Hoc ◽  
Data Sets ◽  
Traffic Data ◽  
Microscopic Traffic Simulation ◽  
Car Following ◽  
Data Segmentation ◽  
Essential Components ◽  
Real Traffic

Empirical speed–density relationships are important not only because of the central role that they play in macroscopic traffic flow theory but also because of their connection to car-following models, which are essential components of microscopic traffic simulation. Multiregime traffic speed– density relationships are more plausible than single-regime models for representing traffic flow over the entire range of density. However, a major difficulty associated with multiregime models is that the breakpoints of regimes are determined in an ad hoc and subjective manner. This paper proposes the use of cluster analysis as a natural tool for the segmentation of speed–density data. After data segmentation, regression analysis can be used to fit each data subset individually. Numerical examples with three real traffic data sets are presented to illustrate such an approach. Using cluster analysis, modelers have the flexibility to specify the number of regimes. It is shown that the K-means algorithm (where K represents the number of clusters) with original (nonstandardized) data works well for this purpose and can be conveniently used in practice.

A Study of Loop Detectors Based on Vehicular Trajectories

2014 ◽  
Vol 505-506 ◽  
pp. 1118-1121
Author(s):  
Han Yang
Keyword(s):  
Traffic Flow ◽  
Traffic Data ◽  
Time And Space ◽  
Fundamental Diagram ◽  
Time Intervals ◽  
Loop Detectors ◽  
Data Collecting ◽  
Detector Location

Vehicular trajectories are firstly achieved on the basis of vehicle time and space information obtained from VISSIM simulation. Via simulating setting loop detectors at different locations and collecting traffic data in different time intervals, different traffic flow fundamental diagrams on the basis of the detect data are then generated. Finally, comparing these fundamental diagrams, two conclusions are achieved. The loop detective interval has a significant impact on fundamental diagrams while the detector location has an extremely limited influence. Particularly, fundamental diagram is more aggregated with longer data collecting interval and capacity is more easily to be obtained with longer distance between neighboring loop detectors.

scholarly journals THE IMPACT OF ACTUATED CONTROL ON THE ENVIRONMENT AND THE TRAFFIC FLOW

2021 ◽  
pp. 1-10
Author(s):  
Ambróz Hájnik ◽  
Alica Kalašová ◽  
Veronika Harantová ◽  
Ján Beňuš ◽  
Stanislav Kubaľák
Keyword(s):  
Environmental Pollution ◽  
Traffic Flow ◽  
Delay Time ◽  
Road Transport ◽  
Traffic Data ◽  
Basic Characteristics ◽  
The Impact ◽  
Positive Results

In our paper, we have analyzed and compared fixed and actuated control at a chosen intersection, where we pointed out the importance of actuated control and its benefits. We have used traffic data from sensors in the roadway. The intersection was modelled in Aimsun, where we performed simulations. The research focused mainly on the impact of actuated control on the basic characteristics of the traffic flow, delay time and emissions. The outputs of simulations showed positive results of actuated control in all compared values. The environmental pollution topic is up-to-date and road transport has a significant impact on it. Furthermore, we want to continue with our research to investigate the impact of speed changes on emission production and the smoothness of the traffic flow under fixed and actuated control.

scholarly journals Traffic Flow Characteristics mining of Time Series Data Based on Phase Space Reconstruction Using Complex Networks

CONVERTER ◽  
2021 ◽  
pp. 146-161
Author(s):  
Xue Xing, Yaqi Zhai, Zhongtai Jiang, Xiaoyu LI
Keyword(s):  
Time Series ◽  
Phase Space ◽  
Network Analysis ◽  
Traffic Flow ◽  
Complex Network ◽  
Degree Distribution ◽  
Data Flow ◽  
Flow Time ◽  
Phase Space Reconstruction ◽  
Traffic Data

Traffic flow time series is vital for mining the traditional statistical characteristics by using the theory of statistics and machine learning when its identity is a special time series. The network analysis of the traffic flow time series, who uses the complex network of time series analysis method, is designed to inquire into the special law of traffic flow time series which uses its visualization characteristics. Through the network analysis of traffic data flow, the connotation of traffic data flow can be revealed, and the relationship between all data and some data can be further studied. Therefore, it is constructed by combination with the phase space reconstruction theory. The phase space trajectory may be squeezed and the structure of attractor may change. We need to use C-C method to estimate the time delay according to the characteristics of integral parameters, and use G-P algorithm to estimate the embedding dimension to avoid it. This study can effectively reveal the motion law of the system. After constructing the complex network of traffic flow time series with various traffic parameters, the degree distribution, clustering coefficient and modularization of the representative critical threshold corresponding network are statistically analysed. The analysis results show that the new networked structure of traffic flow time series proposed in this study has strong advantages, and its core is phase space reconstruction, which can well reflect the information space of traffic dynamic fluctuation. The time series networking method based on phase space reconstruction has become a new approach to inquire into the characteristics of traffic flow time series. The degree distribution of the actual multi-traffic parameter time series construction network satisfies the characteristics of a Gaussian distribution. Their average clustering coefficients have attenuation characteristics, and their modularization degree is obvious.

scholarly journals Overview of emerging road traffic data collection methods

2021 ◽  
Author(s):  
Sandra Mihalinac ◽  
Maja Ahac ◽  
Saša Ahac ◽  
Miroslav Šimun
Keyword(s):  
Data Collection ◽  
Traffic Flow ◽  
Road Network ◽  
Road Traffic ◽  
Traffic Volume ◽  
Transport Systems ◽  
Traffic Data ◽  
Data Collection Methods ◽  
Traffic Data Collection ◽  
Collection Methods

It is a well-known fact that the data on road traffic flow characteristics is essential for sustainable road network management. First road traffic volume counts date back to the 1950s when short-term periodic road traffic counts were carried out in cities worldwide. Manual traffic counting is one of the oldest and most technologically simple methods to obtain data on road traffic volume and its composition. Today, because of the ever-growing road transport demand, it has become clear that the development of Intelligent Transport Systems (ITS) is vital to increase safety and tackle increasing emission and congestion problems. The introduction of ITS highly depends on the quality and quantity of traffic data. Under the growing requirement of long-term traffic flow information, various traffic data collection methods have evolved. They allow systematic recording of the traffic flow volume and composition but also vehicle speed, total gross weight, number of axles, axle load and travel destination. This data, which is collected continuously over longer periods, enables a detailed analysis of traffic flows, and represents the basis for decision making in planning, designing, construction and maintenance of road infrastructure. This paper gives an overview of traditional and emerging traffic data collection methods - both fixed and mobile - and the analysis of the current road traffic data collection methods used on the Croatian road network, in terms of their potential and limitations.

scholarly journals SELECTED ISSUES IN MODELLING OF TRAFFIC FLOWS IN CONGESTED URBAN

2014 ◽  
Vol 29 (1) ◽  
pp. 77-89 ◽  
Author(s):  
Renata Żochowska
Keyword(s):  
Traffic Flow ◽  
Traffic Management ◽  
Transportation Network ◽  
Traffic Flows ◽  
Traffic Shaping ◽  
Dynamic Traffic ◽  
Urban Network ◽  
Traffic Models ◽  
The Subject ◽  
The City

Making rational decisions about the planning and designing the traffic management in the city requires a proper description of traffic flows following through the various elements of the transportation network. This issue is the subject of many studies, resulting in a wide variety of models used in this field. Generally they can be divided into two main groups: models describing the distribution of traffic flows in the transportation network and models describing the transition of traffic flow by individual elements of the transportation network. This article reviews the models used to describe the traffic shaping in such an arrangement. Then the way of describing traffic flows, which may be used in the construction and calibration of dynamic traffic models has been formalized. The article also includes a calculation example with application of the proposed description of the components of traffic flows on the link of urban network.

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