scholarly journals A Three-Phase Fundamental Diagram from Three-Dimensional Traffic Data

Axioms ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 17
Author(s):  
Maria Laura Delle Delle Monache ◽  
Karen Chi ◽  
Yong Chen ◽  
Paola Goatin ◽  
Ke Han ◽  
...  
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Time Estimation ◽  
Travel Time Estimation ◽  
Traffic Data ◽  
Fundamental Diagram ◽  
Model Based Clustering ◽  
Three Phase ◽  
Characterization Of Solutions ◽  
Two Phases

This paper uses empirical traffic data collected from three locations in Europe and the US to reveal a three-phase fundamental diagram with two phases located in the uncongested regime. Model-based clustering, hypothesis testing and regression analyses are applied to the speed–flow–occupancy relationship represented in the three-dimensional space to rigorously validate the three phases and identify their gaps. The finding is consistent across the aforementioned different geographical locations. Accordingly, we propose a three-phase macroscopic traffic flow model and a characterization of solutions to the Riemann problems. This work identifies critical structures in the fundamental diagram that are typically ignored in first- and higher-order models and could significantly impact travel time estimation on highways.

A Fast Digital 3D-SVPWM Algorithm for Four-Leg Converter

2014 ◽  
Vol 541-542 ◽  
pp. 494-497
Author(s):  
Peng Xian Song ◽  
Ping Wang ◽  
Yao Hua Li
Keyword(s):  
Mathematical Model ◽  
Computer Simulation ◽  
Coordinate Transformation ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Space Vector Pwm ◽  
Space Vector ◽  
Computational Burden ◽  
Three Phase ◽  
Three Dimensional Space

The three-phase four-leg converter can be obtained by adding a bridge into the traditional three-phase three-leg converter. The average mathematical model of three-phase four-leg converter is described in this paper. The three-dimensional space vector PWM (3D-SVPWM) is analyzed. For simplifying the modulation, a fast digital SVPWM algorithm which eliminates coordinate transformation and saves calculating time was proposed. The feasibility of the proposed modulation technique is verified by computer simulation. These results show that the proposed fast digital 3D-SVPWM technique can be easily implemented without conventional computational burden.

FUNDAMENTAL APPROACH TO THE COSMOLOGICAL CONSTANT ISSUE

2002 ◽  
Vol 17 (29) ◽  
pp. 4219-4228 ◽  
Author(s):  
MOSHE CARMELI
Keyword(s):  
Cosmological Constant ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Phase Evolution ◽  
Positive Pressure ◽  
Field Equations ◽  
Accelerating Expansion ◽  
Three Phase ◽  
The Universe ◽  
Three Dimensional Space

We use a Riemannian four-dimensional presentation for gravitation in which the coordinates are distances and velocity rather than the traditional space and time. We solve the field equations and show that there are three possibilities for the Universe to expand. The theory describes the Universe as having a three-phase evolution with a decelerating expansion, followed by a constant and an accelerating expansion, and it predicts that the Universe is now in the latter phase. It is shown, assuming Ωm = 0.245, that the time at which the Universe goes over from a decelerating to an accelerating expansion, occurs at 8.5 Gyr ago, at which time the cosmic radiation temperature was 146K. Recent observations show that the Universe's growth is accelerating. Our theory confirms these recent experimental results. The theory predicts also that now there is a positive pressure in the Universe. Although the theory has no cosmological constant, we extract from it its equivalence and show that Λ = 1.934 × 10-35 s-2. This value of Λ is in excellent agreement with measurements. It is also shown that the three-dimensional space of the Universe is Euclidean, as the Boomerang experiment shows.

An Method to Urban Road Travel Time Estimation through ITS Data Fusion Based on D-S Evidential Theory

2014 ◽  
Vol 488-489 ◽  
pp. 1419-1425 ◽  
Author(s):  
Jing Xin Xia ◽  
Wei Hua Zhang ◽  
Dang Sheng Ma
Keyword(s):  
Travel Time ◽  
Time Estimation ◽  
Estimation Methods ◽  
Estimation Accuracy ◽  
Identification System ◽  
Travel Time Estimation ◽  
Traffic Data ◽  
Data Resource ◽  
Evidential Theory ◽  
Link Travel Time

Focused on the current situations of the multiple traffic data collection efforts for urban roads, the link travel time estimation methods are respectively proposed based on two traffic data resources as station traffic data collected by microwave detectors and the vehicle plate data collected by the video vehicle plate identification system. Based on this, the link travel time estimation approach by fusing two data resources is presented using the Dempster-Shafer evidence reasoning theory, in which the probability distribution function is firstly used to construct the evidence function for each data resource, and then the weights for the two different data resources are estimated for link travel time fusion estimation through the combination rule of Dempster-Shafer evidence reasoning theory. Using the true link travel time collected by the test vehicles, the performance of the proposed method for link travel time estimation is evaluated. Evaluation results show that the proposed method can significantly improve the link travel time estimation accuracy when compared to the methods that merely uses single data resource.

scholarly journals Arterial travel time estimation method using SCATS traffic data based on KNN-LSSVR model

2019 ◽  
Vol 11 (5) ◽  
pp. 168781401984192 ◽  
Author(s):  
Qichun Bing ◽  
Dayi Qu ◽  
Xiufeng Chen ◽  
Fuquan Pan ◽  
Jinli Wei
Keyword(s):  
Travel Time ◽  
Estimation Method ◽  
Time Estimation ◽  
Travel Time Estimation ◽  
Traffic Data
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