scholarly journals Research on the Traffic Flow Control of Urban Occasional Congestion Based on Catastrophe Theory

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Yang Xu ◽  
Duo Jia Zhang ◽  
Xin Zhang ◽  
Kin Keung Lai ◽  
Bing Su
Keyword(s):  
Congestion Control ◽  
Traffic Flow ◽  
Catastrophe Theory ◽  
Control Method ◽  
Cusp Catastrophe ◽  
Urban Road ◽  
The Road ◽  
Catastrophe Model ◽  
Cusp Catastrophe Theory ◽  
Road System

Aimed at the problem of occasional congestion control, the cusp catastrophe theory is used to establish the catastrophe model of the urban road system under occasional congestion, finding breakpoints and analyzing stability after urban road system catastrophes by constructing the energetic function; based on the catastrophe characteristics of the urban road system, the feasibility method of congestion control is discussed. The results show that the control method of traffic flow based on catastrophe characteristics of the urban road system can effectively improve the efficiency of the road system in theory. Finally, the applicability of the control method based on catastrophe characteristics is analyzed by examples under different occasional congestion situations.

scholarly journals An Analysis of the Catastrophe Model and Catastrophe Characteristics of Traffic Flow Based on Cusp Catastrophe Theory

2022 ◽  
Vol 2022 ◽  
pp. 1-11
Author(s):  
Yanguo Huang ◽  
Huiming Zhang ◽  
Hongjun Liu ◽  
Shengsheng Zhang
Keyword(s):  
Traffic Flow ◽  
Catastrophe Theory ◽  
Wave Speed ◽  
Road Traffic ◽  
Traffic Density ◽  
Cusp Catastrophe ◽  
Flow State ◽  
Analysis Method ◽  
Urban Road ◽  
Catastrophe Model

—The state of urban road traffic flow shows discontinuity and jumping phenomenon in the process of running. There was a data gap in the collected traffic flow data. Through the data analysis, it was found that the traffic flow state had the characteristics of multimode, mutation, inaccessibility, divergence and hysteresis, which were similar to the mutation characteristics of the basic model of catastrophe theory when the system state changed. The cusp catastrophe model of traffic flow based on traffic wave theory was established by analyzing the movement process of traffic flow. In this model, the traffic density was taken as the state variable, and traffic flow and wave speed were taken as the control variable. Referring to the basic idea of catastrophe theory, the solution method of the model was given, and the structural stability of the traffic flow state was analyzed. Through the critical equilibrium surface equation, the stability of the extreme value of the system potential function can be analyzed, and the bifurcation set equation when the traffic flow state changed can be obtained, which can be used to determine the critical range of the structural stability of the system. This paper discussed and analyzed the changing trend and constraint relationship among the wave speed, traffic density and traffic flow when the traffic flow state changed suddenly in different running environments. The analysis results were consistent with the actual road traffic flow state. A case was given, and the results showed that the cusp catastrophe model could describe the relationship among the three parameters of traffic flow from three-dimensional space, and could effectively analyze the internal relationship of the parameters when the traffic flow state changed. The validity of the model and analysis method was verified. The goal of this paper is to provide an analysis method for the judgment of urban road traffic state.

scholarly journals Traffic Flow Catastrophe Border Identification for Urban High-density Area Based on Cusp Catastrophe Theory: A Case Study under Sudden Fire Disaster

2020 ◽  
Author(s):  
Ciyun Lin ◽  
Yongli Yu ◽  
Dayong Wu ◽  
Bowen Gong
Keyword(s):  
Data Collection ◽  
Traffic Flow ◽  
Catastrophe Theory ◽  
Traffic Congestion ◽  
High Density ◽  
Cusp Catastrophe ◽  
High Density Area ◽  
Density Area ◽  
Fire Disaster ◽  
Cusp Catastrophe Theory

For traffic management under sudden disaster in high-density areas, the first and foremost step is to prevent traffic congestion in the disaster-affected area by traffic flow control, as to provide enough and flexible traffic capacity for emergency evacuation and emergency rescue. Catastrophe border identification is the foundation and the key to traffic congestion prediction under sudden disaster. This paper uses a mathematical model to study the regional traffic flow in the high-density area under sudden fire disaster based on the Cusp Catastrophe Theory (CCT). The catastrophe border is identified by fitting the CCT-based regional traffic flow model to explore the stable traffic flow changing to the instable state, as to provide a theoretical basis for traffic flow manage and control in disaster-affected areas, and to prevent the traffic flow being caught into disorder and congestion. Based on VISSIM simulator data by building simulation scenarios with and without sudden fire disaster in a Sudoku traffic network, the catastrophe border is identified as 439pcu/lane/h, 529pcu/lane/h, 377pcu/lane/h at 5s, 10s, 15s data collection interval respectively. The corresponding relative precision, which compares to the method of Capacity Assessment Approach (CAA), is 89.1%, 92.7% and 76.5% respectively. It means that 10s data collection interval would be the suitable data collection interval in catastrophe border identification and regional traffic flow control in high-density area under sudden fire disaster.

Analysis of Global Safety Degree of Arch Dam Based on Catastrophe Theory

2014 ◽  
Vol 1065-1069 ◽  
pp. 547-551 ◽  
Author(s):  
Lin Song Sun ◽  
Yun Peng He
Keyword(s):  
Catastrophe Theory ◽  
Strain Energy ◽  
Fe Analysis ◽  
Arch Dam ◽  
Instability Criterion ◽  
Cusp Catastrophe ◽  
Catastrophe Model ◽  
Plastic Yield ◽  
Plastic Strain Energy ◽  
Cusp Catastrophe Theory

The cusp catastrophe theory was introduced to the evaluation of the global safety of a system of an arch dam and its foundation, and the relevant quantitative instability criterion was established. Based on the overload nonlinear FE analysis of a planned arch dam, the global safety degree of this arch dam was 2.75 according to the instability criterion of the cusp catastrophe model of plastic strain energy, and the evaluation result was in agreement with the transfixion criterion of the plastic yield area.

Make More Connections: Urban Traffic Flow Forecasting with Spatiotemporal Adaptive Gated Graph Convolution Network

2022 ◽  
Vol 13 (2) ◽  
pp. 1-25
Author(s):  
Bin Lu ◽  
Xiaoying Gan ◽  
Haiming Jin ◽  
Luoyi Fu ◽  
Xinbing Wang ◽  
...  
Keyword(s):  
Traffic Flow ◽  
Road Network ◽  
Large Scale ◽  
Transportation Systems ◽  
Urban Traffic ◽  
Propagation Mechanism ◽  
Urban Road ◽  
The Road ◽  
Traffic Flow Forecasting ◽  
Gating Mechanism

Urban traffic flow forecasting is a critical issue in intelligent transportation systems. Due to the complexity and uncertainty of urban road conditions, how to capture the dynamic spatiotemporal correlation and make accurate predictions is very challenging. In most of existing works, urban road network is often modeled as a fixed graph based on local proximity. However, such modeling is not sufficient to describe the dynamics of the road network and capture the global contextual information. In this paper, we consider constructing the road network as a dynamic weighted graph through attention mechanism. Furthermore, we propose to seek both spatial neighbors and semantic neighbors to make more connections between road nodes. We propose a novel Spatiotemporal Adaptive Gated Graph Convolution Network ( STAG-GCN ) to predict traffic conditions for several time steps ahead. STAG-GCN mainly consists of two major components: (1) multivariate self-attention Temporal Convolution Network ( TCN ) is utilized to capture local and long-range temporal dependencies across recent, daily-periodic and weekly-periodic observations; (2) mix-hop AG-GCN extracts selective spatial and semantic dependencies within multi-layer stacking through adaptive graph gating mechanism and mix-hop propagation mechanism. The output of different components are weighted fused to generate the final prediction results. Extensive experiments on two real-world large scale urban traffic dataset have verified the effectiveness, and the multi-step forecasting performance of our proposed models outperforms the state-of-the-art baselines.

Study of Setting of Bus Bay Stop Based on VISSIM

2014 ◽  
Vol 641-642 ◽  
pp. 906-909
Author(s):  
Jian Jun Wang ◽  
Xin Ting Huang ◽  
Ning Zhao
Keyword(s):  
Traffic Flow ◽  
Delay Time ◽  
Road Traffic ◽  
Microscopic Simulation ◽  
Total Delay ◽  
Urban Road ◽  
Bus Stop ◽  
Road Design ◽  
Bus Station ◽  
Road System

Setting state of bus stop affects the efficiency of the entire road system. Through discussing bus bay stop’s width, length and distance to intersection, a microscopic simulation was conducted in this paper. With a certain bus frequency, the total delay time of vehicles was analyzed under different road traffic in different forms of Da Yanta Bus Station in Xi’an. The results show that setting bus bay stops on the secondary roads which have large traffic flow can significantly reduce delay time, and can provide references for urban road design.

A novel index based on the cusp catastrophe theory for predicting harmful algae blooms

2019 ◽  
Vol 102 ◽  
pp. 746-751 ◽  
Author(s):  
Yimei Tian ◽  
Bo Zheng ◽  
Hailiang Shen ◽  
Shengnan Zhang ◽  
Yaru Wang
Keyword(s):  
Catastrophe Theory ◽  
Harmful Algae ◽  
Cusp Catastrophe ◽  
Harmful Algae Blooms ◽  
Algae Blooms ◽  
Cusp Catastrophe Theory

Study on the Slope Stability Based on Catastrophe Theory

2011 ◽  
Vol 261-263 ◽  
pp. 1489-1493 ◽  
Author(s):  
Jun Zheng He ◽  
Ke Qiang He ◽  
Yong Shan Yan ◽  
Wei Hao
Keyword(s):  
Catastrophe Theory ◽  
Slope Failure ◽  
Yield Criterion ◽  
Control Variable ◽  
Reduction Factor ◽  
Cusp Catastrophe ◽  
Strength Reduction Factor ◽  
Catastrophe Model ◽  
Cusp Catastrophe Model ◽  
Vertical Displacements

Based on the Drucker-Prager yield criterion which matches with the Mohr-Coulomb yield criterion under the plane strain condition, this paper sets up a cusp catastrophe model of maximum horizontal and vertical displacements to strength reduction factor by using the cusp catastrophe theory. And the catastrophe criterion of slope failure is quantified to the control variable (u) and discriminant (△) which are evaluated by comparing with zero. Taking the above study as the foundation, the cusp catastrophe model is applied to solve one of the standard test ACADS examples. On the two criterions for slope failure of horizontal and vertical displacements catastrophe model, the safety factor of the slope is 0.988 which is consistent with those by ACAS. It shows that the cusp catastrophe model in slope failure analysis is feasible and practical.

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