A Study on Inter-region Flow Control of Urban Traffic: A Modification of the Greedy Control Strategy

2019 ◽  
Author(s):  
Sunghoon Kim ◽  
Hwapyeong Yu ◽  
Hwasoo Yeo
Keyword(s):  
Flow Control ◽  
Control Strategy ◽  
Urban Traffic ◽  
Region Flow

Methodology to Increase Flexibility in Inter-Region Flow Control for Urban Traffic

2021 ◽  
pp. 036119812199742
Author(s):  
Sunghoon Kim ◽  
Monica Menendez ◽  
Hwasoo Yeo
Keyword(s):  
Flow Control ◽  
Real Time ◽  
Urban Traffic ◽  
Test Results ◽  
Flow Restriction ◽  
Region Flow ◽  
The Subject ◽  
Negative Impacts ◽  
Transfer Flow ◽  
Supply Level

Perimeter control is used to regulate transfer flows between urban regions. The greedy control (GC) method takes either the minimum or the maximum for the control inputs. Although it has the advantage of simplicity for real-time feasibility, a few existing studies have shown that it can sometimes have negative impacts because of unnecessary transfer flow restrictions. To reduce unnecessary restrictions, this study provides a method that gives flexibility to ease the strict conditions of the conventional GC. First, we propose a modification as a way of granting exceptions to the flow restriction under specific conditions. Second, we develop an algorithm to determine the threshold dynamically for accepting the exception, by comparing the possible outflow loss of the subject region and the possible outflow gain of its neighboring regions. The test results show that this flexible greedy control can handle the balance between the transfer demands and the greed of regions for securing the supply level, while increasing the performance in both vehicle hours traveled and trip completion.

Collaborative passenger flow control of urban rail transit network considering balanced distribution of passengers

2021 ◽  
pp. 2150461
Author(s):  
Xiang Li ◽  
Yan Bai ◽  
Kaixiong Su
Keyword(s):  
Flow Control ◽  
Programming Model ◽  
Flow Characteristics ◽  
Service Level ◽  
Urban Traffic ◽  
Urban Rail Transit ◽  
Control Measures ◽  
Rail Transit ◽  
Passenger Flow ◽  
Urban Rail

The increase of urban traffic demands has directly affected some large cities that are now dealing with more serious urban rail transit congestion. In order to ensure the travel efficiency of passengers and improve the service level of urban rail transit, we proposed a multi-line collaborative passenger flow control model for urban rail transit networks. The model constructed here is based on passenger flow characteristics and congestion propagation rules. Considering the passenger demand constraints, as well as section transport and station capacity constraints, a linear programming model is established with the aim of minimizing total delayed time of passengers and minimizing control intensities at each station. The network constructed by Line 2, Line 6 and Line 8 of the Beijing metro is the study case used in this research to analyze control stations, control durations and control intensities. The results show that the number of delayed passengers is significantly reduced and the average flow control ratio is relatively balanced at each station, which indicates that the model can effectively relieve congestion and provide quantitative references for urban rail transit operators to come up with new and more effective passenger flow control measures.

Modeling and Designing of Urban Traffic Control Systems by Statecharts

2011 ◽  
Vol 308-310 ◽  
pp. 1582-1585
Author(s):  
Yi Sheng Huang ◽  
Tso Hsien Liao
Keyword(s):  
Boolean Function ◽  
Control Systems ◽  
Dynamic Model ◽  
Control Strategy ◽  
Traffic Control ◽  
Propositional Logic ◽  
Urban Traffic ◽  
Hierarchical Tree ◽  
Tree Diagram ◽  
Urban Traffic Control

Statechart has been utilized as a visual formalism for the modeling of complex systems. It illuminates the features on describing properties of causality, concurrency and synchronization. The reachability structure is used to represented dynamic model by a Boolean function. In this paper, we try to describe State invariant method and equation function for hierarchical tree diagram. Finally, we used them to analyze the urban traffic control systems which are modeled by using Statecharts. Their formalism provides a concept of propositional logic for presenting control strategy.

Control Strategies for Multistage Solar Collector Systems

1988 ◽  
Vol 110 (3) ◽  
pp. 230-232
Author(s):  
C. Saltiel
Keyword(s):  
Comparative Study ◽  
Flow Control ◽  
Numerical Simulations ◽  
Control Strategy ◽  
System Performance ◽  
Solar Collector ◽  
Control Strategies ◽  
Climatic Conditions ◽  
High Threshold ◽  
Threshold Values

A comparative study of the yearly performance of multistage solar collector systems, (comprised of more than one collector type) with a single on/off flow control strategy for all the collectors and separate on/off controls for each collector stage, is performed. Detailed numerical simulations under a range of climatic conditions showed that there is little advantage in using individual collector controls over a single on/off control strategy when the systems operate at low collector thresholds, but differences in system performance can be quite significant at high threshold values. In addition, the choice of the single control strategy (i.e., which collector the strategy is based on) at low thresholds is not critical in terms of system performance.

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