Application of Catastrophe Theory in Traffic Flow of Highway Tunnel Group

2013 ◽  
Vol 734-737 ◽  
pp. 1609-1612
Author(s):  
Wei Zhan ◽  
Yue Quan Shang ◽  
Feng Xia Chi
Keyword(s):  
Traffic Flow ◽  
Traffic Control ◽  
Catastrophe Theory ◽  
Critical Density ◽  
Flow Characteristics ◽  
Control Measures ◽  
Highway Tunnel ◽  
Relationship Of ◽  
The Relationship ◽  
Highway Management

Based on the investigation of traffic flow in a typical highway tunnel group, the traffic flow characteristics were analyzed by catastrophe theory with the relationship of the speed, volume and density. The discontinuous leaping change phenomenon of the traffic data under large traffic volume is better explained by the catastrophe model than the traditional ways. The value of critical density can be obtained by analyzing the critical state of traffic flow. Then the traffic flow warning can be realized in highway tunnel group region. The data and results can be used for the reference of taking traffic control measures by highway management.

scholarly journals Developing a New Spatial Unit for Macroscopic Safety Evaluation Based on Traffic Density Homogeneity

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Chen Wang ◽  
Lin Liu ◽  
Chengcheng Xu
Keyword(s):  
Traffic Flow ◽  
Traffic Control ◽  
Flow Characteristics ◽  
Traffic Density ◽  
Minimization Method ◽  
Spatial Unit ◽  
Flow Parameters ◽  
Safety Knowledge ◽  
Traffic Operation ◽  
Crash Modeling

Macrolevel crash modeling has been extensively applied to investigate the safety effects of demographic, socioeconomic, and land use factors, in order to add safety knowledge into traffic planning and policy-making. In recent years, with the increasing attention to regional traffic management and control, the safety effects of macrolevel traffic flow parameters may also be of interest, in order to provide useful safety knowledge for regional traffic operation. In this paper, a new spatial unit was developed using a recursive half-cut partitioning procedure based on a normalized cut (NC) minimization method and traffic density homogeneity. Two Bayesian lognormal models with different conditional autoregressive (CAR) priors were applied to examine the safety effects of traffic flow characteristics at the NC level. It was found that safety effects of traffic flow exist at such macrolevel, indicating the necessity of considering safety for regional traffic control and management. Furthermore, traffic flow effects were also examined for another two spatial units: Traffic Analysis Zone (TAZ) and Census Tract (CT). It was found that ecological fallacy and atomic fallacy could exist without considering traffic flow parameters at those planning-based levels. In general, safety needs to be considered for regional traffic operation and the effects of traffic flow need to be considered for spatial crash modeling at various spatial levels.

scholarly journals The Dynamical Decision Model of Intersection Congestion Based on Risk Identification

2020 ◽  
Vol 12 (15) ◽  
pp. 5923 ◽  
Author(s):  
Xu Sun ◽  
Kun Lin ◽  
Pengpeng Jiao ◽  
Huapu Lu
Keyword(s):  
Traffic Flow ◽  
Traffic Control ◽  
Traffic Congestion ◽  
Decision Model ◽  
Risk Identification ◽  
Control Measures ◽  
Evaluation Index System ◽  
Actual Condition ◽  
Basic Model ◽  
Risk Degree

The paper focuses on the problem of traffic congestion at intersection based on the mechanism of risk identification. The main goal of this study is to explore a new methodology for identifying and predicting the intersection congestion. Considering all the factors influencing the traffic status of intersection congestion, an integrated evaluation index system is constructed. Then, a detailed dynamic decision model is proposed for identifying the risk degree of the traffic congestion and predicting its influence on future traffic flow, which combines the traffic flow intrinsic properties with the basic model of the Risking Dynamic Multi-Attribute Decision-Making theory. A case study based on a real-world road network in Baoji, China, is implemented to test the efficiency and applicability of the proposed modeling. The evaluation result is in accord with the actual condition and shows that the approach proposed can determine the likelihood and risk degree of the traffic congestion occurring in the intersection, which can be used as a tool to help transport managers make some traffic control measures in advance.

scholarly journals Avirulence gene based RFLP and rep-PCR distinguish the genetic variation of Xanthomonas oryzae pv. oryzae pathotypes in Bangladesh

2022 ◽  
Vol 9 (1) ◽  
pp. 29-40
Author(s):  
Mohammad Mahbubul Haque ◽  
Md. Mostafa Masud ◽  
Samrin Bashar ◽  
Mohammad Iqbal Hossain ◽  
Md. Zahangir Alam ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Bacterial Blight ◽  
Phylogenetic Analyses ◽  
Control Measures ◽  
Avirulence Gene ◽  
Effective Control ◽  
Repeat Domain ◽  
Relationship Of ◽  
The Relationship ◽  
Pcr Techniques

Bacterial blight (BB) caused by X. oryzae pv. oryzae is one of the devastating diseases of rice mostly in Asia. Genomes of X. oryzae pv. oryzae is highly variable due to rearrangement of the large contents of transposable elements and dynamic changes of X. oryzae pv. oryzae population regulated efficiency of the control measures used for BB management of rice worldwide. In this study, genetic variation of X. oryzae pv. oryzae pathotypes of Bangladesh was studied using aviruelnce gene based RFLP and rep-PCR techniques aimed to formulate pathogen targeted effective control measures against BB of rice. Eight pathotypes of X. oryzae pv. oryzae field isolates were identified based on their reactions against 10 Near Isogenic Lines (NILs). Among eight pathotypes, pathotypes IV and V contained higher number of isolates which were 30.13% and 23.01% respectively while pathotype VIII revealed as minimum containing only 2.51% of total isolates. These eight pathotypes were studied for their genetic variation by RFLP using avrBs3 repeat domain as probe. The results conceded that Bangladeshi X. oryzae pv. oryzae strains seem carrying a minimum of two and maximum of nine avrBs3 family genes homologs. The resistance phenotype on IRBB7 and IRBB10 NILs also indicated presence of two major avrBs3 family genes viz. avrxa7 and avrXa10 in some pathotypes. Relationship of phylogenicity exhibited that X. oryzae pv. oryzae pathotypes assorted into two RFLP haplotypes as well as these haplotypes are largely distributed in Bangladesh. Phylogenetic analyses carried out by (REP, ERIC), rep-PCR and BOX depicted the presence of two main molecular haplotypes of X. oryzae pv. oryzae pathotypes. The relationship between pathotypes and molecular haplotypes of X. oryzae pv. oryzae in Bangladesh indicated that the same lineage possesses different pathotypes and different lineage possesses different pathotypes. The results indicated that eight different pathotypes might have originated from common inherited haplotypes with a wide genetic variation.

Influence of fiber laminated thickness on the hygrothermal property of HNT-GFRP nanocomposites for the RFI process-based structures

2019 ◽  
Vol 33 (14n15) ◽  
pp. 1940051
Author(s):  
Soo-Jeong Park ◽  
Yun-Hae Kim
Keyword(s):  
Moisture Absorption ◽  
Water Environment ◽  
Flow Characteristics ◽  
External Pressure ◽  
Curing Process ◽  
High Temperature Water ◽  
Relationship Of ◽  
The Relationship ◽  
Temperature Water

Glass fiber–halloysite nanotube (GF/HNT) nanocomposites were fabricated with different numbers of fiber layers and were exposed to a high-temperature water environment to analyze the role of the HNTs regarding the relationship of interface between the fibers and the moisture absorption behavior. The sections of the GF/HNT nanocomposite plates were divided, and the change in the moisture absorption rate was measured. As a result, the ratio of the HNT to epoxy resin was not related to the water deterioration phenomenon according to the fiber-laminated thickness. However, in the curing process after the vacuum bag molding, the external pressure that was applied to each interface influences the flow characteristics and promotes the occurrence of HNT agglomeration, which interferes with interfacial crosslinking.

scholarly journals Left-Side On-Ramp Metering for Improving Safety and Efficiency in Underground Expressway Systems

2019 ◽  
Vol 11 (12) ◽  
pp. 3247 ◽  
Author(s):  
Minhua Shao ◽  
Congcong Xie ◽  
Lijun Sun ◽  
Xiaomin Wan ◽  
Zhang Chen
Keyword(s):  
Traffic Flow ◽  
Traffic Safety ◽  
Traffic Control ◽  
Flow Characteristics ◽  
Ramp Metering ◽  
Accident Risk ◽  
Data Traffic ◽  
Traffic Efficiency ◽  
Traffic Characteristics ◽  
Two Parameter

As one of the effective measures of intelligent traffic control, on-ramp metering is often used to improve the traffic efficiency of expressways. Existing on-ramp metering research mainly discusses expressways with right-side on-ramps. However, for underground expressway systems (UESs), left-side on-ramps are frequently adopted to reduce the ground space occupied by ramp construction. Since traffic entering from the left and right sides of the mainline may have different traffic characteristics, on-ramp metering for UESs with left-side on-ramps should be explored specifically. This study examines the impacts of left-side on-ramps on the traffic safety and efficiency of UESs and proposes an effective on-ramp metering strategy. Firstly, using field data, traffic flow fundamental diagrams and speed dispersion are discussed to explore the traffic flow characteristics of the “left-in” UES. The results show that the capacity and critical occupancy are both reduced in left-side on-ramp compared to right-side on-ramp expressways. Meanwhile, the speed dispersion is higher in left-side on-ramp UESs, which means a higher accident risk. Based on this, considering traffic safety and efficiency, a novel two-parameter left-side on-ramp metering strategy for UESs is proposed, in which occupancy and speed are used as the control indicators simultaneously. Additionally, the mechanism of the metering strategy is explained. Finally, the proposed on-ramp metering strategy is simulated on a real UES. The results demonstrate the advantages of the proposed two-parameter on-ramp metering strategy for improving the traffic safety and efficiency of UESs.

EFFECT OF RAINFALL ON TRAFFIC FLOW CHARACTERISTICS DURING NIGHT TIME

2016 ◽  
Vol 78 (7-2) ◽  
Author(s):  
Nurul ‘Azizah Mukhlas ◽  
Nordiana Mashros ◽  
Othman Che Puan ◽  
Sitti Asmah Hassan ◽  
Norhidayah Abdul Hassan ◽  
...  
Keyword(s):  
Traffic Flow ◽  
Flow Characteristics ◽  
Mean Flow ◽  
Night Time ◽  
Lighting Condition ◽  
Adverse Weather ◽  
Traffic Flow Characteristics ◽  
Rural Highway ◽  
The Impact ◽  
The Relationship

Understanding traffic behavior for obtaining a smooth, safe and economical traffic operation requires a thorough knowledge of traffic flow parameters and their mutual relationships.Eventhough adverse weather can reduce traffic efficiencies, there are still questions to answer regarding the relationship between weather conditions and traffic flow at night. This paper presents an investigation of the rainfall effects to the traffic flow characteristics on atwo-lane rural highway during night time. The traffic data and corresponding rainfall data for uninterrupted road segment of Federal route 3 at Dungun, Terengganu were collected under road lighting condition during the north-east monsoon season. The effect of good weather condition, light rain, moderate rain and heavy rain conditions on speed, flow and density were quantified and compared. Results from the analysis indicate that mean speed, mean flow and mean density are reduced under various rainfall conditions. In general, the impact of good weather and various rainfall conditions on Greenshield’s fundamental traffic flow relationship have weak correlations except for the relationship between flow and density. The important points in the fundamental diagram derived from flow-density relationships indicated that critical density, maximum flow, critical speed, jam density and free flow speed of roadway all decrease as rainfall intensity increases. It can be concluded that traffic flow characteristics of two-lane rural highway in Terengganu are affected by rainfall conditions.

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