scholarly journals The Influence of Geometry on Operational Performance of Signal-Controlled Junctions

2010 ◽  
Author(s):  
Dimitris Sermpis
Keyword(s):  
Traffic Flow ◽  
Significant Role ◽  
Linear Models ◽  
Fixed Time ◽  
Operational Performance ◽  
Signal Control ◽  
Light Traffic ◽  
Geometric Characteristics ◽  
Lane Width ◽  
Log Linear

The aim of this study is to investigate the influence of geometry on the performance of signal-controlled road junctions under fixed-time and system D traffic responsive signal control by using 16 experimental scenarios with several different traffic and geometric characteristics. In the estimated log-linear models for delay per unit of time, the principal effects of lane width and turning radii were as expected. The effect on delay of the interaction between lane width and turning radii was found to be of substantial importance at light traffic flow, while the interaction between turning radii and signal control was found to play a significant role at medium traffic flow.

scholarly journals Self-organisation in traffic signal control algorithms under light traffic conditions

ORiON ◽  
2019 ◽  
Vol 35 (1) ◽  
pp. 57-87
Author(s):  
SJ Movius ◽  
JH Van Vuuren
Keyword(s):  
Simulation Model ◽  
Traffic Simulation ◽  
Control Method ◽  
Fixed Time ◽  
Traffic Signal ◽  
Signal Control ◽  
Traffic Signal Control ◽  
Light Traffic ◽  
Traffic Conditions ◽  
Self Organisation

Fixed-time control and vehicle-actuated control are two distinct types of traffic signal control. The latter control method involves switching traffic signals based on detected traffic flows and thus offers more flexibility (appropriate for lighter traffic conditions) than the former, which relies solely on cyclic, predetermined signal phases that are better suited for heavier traffic conditions. The notion of self-organisation has relatively recently been proposed as an alternative approach towards improving traffic signal control, particularly under light traffic conditions, due to its flexible nature and its potential to result in emergent behaviour. The effectiveness of five existing self-organising traffic signal control strategies from the literature and a fixed-control strategy are compared in this paper within a newly designed agent-based, microscopic traffic simulation model. Various shortcomings of three of these algorithms are identified and algorithmic improvements are suggested to remedy these deficiencies. The relative performance improvements resulting from these algorithmic modifications are then quantified by their implementation in the aforementioned traffic simulation model. Finally, a new self-organising algorithm is proposed that is particularly effective under lighter traffic conditions.

scholarly journals Optimization design of traffic flow under security based on cellular automata model

2015 ◽  
Vol 12 (2) ◽  
pp. 427-443 ◽  
Author(s):  
Fan Zhang ◽  
Zhike Han ◽  
Hanyu Ge ◽  
Yingping Zhu
Keyword(s):  
Cellular Automata ◽  
Traffic Flow ◽  
Significant Role ◽  
Heavy Traffic ◽  
Real Life ◽  
Actual Data ◽  
Speed Limit ◽  
Light Traffic ◽  
Cellular Automata Model ◽  
Collision Model

Cellular Automata is a discrete model studied in computability theory, mathematics, physics, complexity science, theoretical biology and microstructure modeling. This paper proposes a model to balance the flux and safety, to maximize the flux on each road whilst ensuring work well with safety based on the Cellular Automata. In order to analyze the flow of traffic, the traffic of three-lane freeway and four-lane freeway are simulated based on the cellular automata model with the factors of velocity and density in the first step. For safety, a rear-end collision model and overtaking lateral collision model were employed to analyze the relation among safety. Reaction time and distance are introduced in the model, and different vehicles are considered. Safety-related factors are also chosen based on back propagation neural network. At last, this paper establishes a model to examine the performance of the traffic flow under the multi-lane freeway in light and heavy traffic. It simulates the situation in real life based on actual data. The optimal relation and optimal value has worked out between flux and safety through simulating the situation in real life based on actual data. To achieve a better model, further discussion, is made on how to adapt to different situations with the keep-left, the unrestricted, and the intelligent system controlled. The experimental result shows that the number of lanes is not an influential factor under any circumstances. The maximum speed limit plays a significant role in light traffic while it is of no importance in heavy traffic. However, the minimum speed limit plays a significant role in heavy traffic while it is of no importance in light traffic.

Effect of recombinant bovine somatotropin on pregnancy rates of Nellore cows resynchronized with the use of new DIB and third use, and inseminated at fixed-time

2015 ◽  
Vol 4 (1) ◽  
pp. 356-362
Author(s):  
Josemara Silva Santos ◽  
Tania Cavalcante ◽  
Francisca Elda Ferreira Dias ◽  
Domenica Palomaris Mariano de Souza ◽  
Alencariano J.S. Falcão ◽  
...  
Keyword(s):  
Artificial Insemination ◽  
Linear Models ◽  
Plasma Concentrations ◽  
Fixed Time ◽  
Estradiol Benzoate ◽  
Pregnancy Rates ◽  
Recombinant Bovine Somatotropin ◽  
Equine Chorionic Gonadotropin ◽  
Rectal Palpation ◽  
Intravaginal Device

The objective of the experiment was to evaluate the effects of recombinant bovine somatropin (rbST), and the reuse of the progesterone (P4) releasing devices in resynchronization, on the pregnancy rates of Nellore cows submitted to fixed-time artificial insemination. A group of 123 multiparae Nellore cows, was submitted to a resynchronization protocol: on day 0 a Bovine Intravaginal Device (DIB® ) with 1,0g of P4 was implanted, associated with intramuscular administration of 2,0mg of estradiol benzoate (IM); on day 8 DIB was removed; and 1,0mg of estradiol cypionate, 0,15mg of prostaglandin F2? and 300 UI of equine chorionic gonadotropin were administered; on day 10, fixed-time artificial insemination was conducted (FTAI). The cows were randomized into G1 (n=12) – without rbST / with used Bovine Intravaginal Device, G2 (n=50) – without rbST / with new DIB, G3 (n=11) - with rbST / with used DIB and G4 (n=50) – with rbST/ with new DIB. rbST was introduced on the eighth day of the protocol. Sixty days after TAI, pregnancy diagnoses were conducted, via rectal palpation. Blood samples were taken on day 0, 8 and 10 of the protocol, in order to assess P4 plasma concentrations. Pregnancy rates were statistically evaluated through Generalized Linear Models Theory and their significance was tested with Analysis of Deviance. Pregnancy rates were 58%, 40%, 81% and 48% for G1, G2, G3 and G4, respectively, with significant statistical difference for G3. Plasma concentrations of P4 were not statistically different among groups, or collections. In view of the results obtained, we concluded that the administration of rbST in association with P4 DIB, used for the third time, improves pregnancy rates. Estrus resynchronization and re-insemination positively impacted pregnancy rates.

When and why are log-linear models self-normalizing?

2015 ◽  
Author(s):  
Jacob Andreas ◽  
Dan Klein
Keyword(s):  
Linear Models ◽  
Log Linear

Log-Linear Models with Dependent Spatial Data

1983 ◽  
Vol 15 (6) ◽  
pp. 801-813 ◽  
Author(s):  
B Fingleton
Keyword(s):  
Spatial Data ◽  
Statistical Models ◽  
Linear Models ◽  
Square Lattice ◽  
Categorical Variables ◽  
Systematic Sampling ◽  
Pairwise Correlations ◽  
Independent Observations ◽  
Intersection Points ◽  
Log Linear

Log-linear models are an appropriate means of determining the magnitude and direction of interactions between categorical variables that in common with other statistical models assume independent observations. Spatial data are often dependent rather than independent and thus the analysis of spatial data by log-linear models may erroneously detect interactions between variables that are spurious and are the consequence of pairwise correlations between observations. A procedure is described in this paper to accommodate these effects that requires only very minimal assumptions about the nature of the autocorrelation process given systematic sampling at intersection points on a square lattice.

Research and Improvement of the Keep-Right-Except-to-Pass Rule

2014 ◽  
Vol 915-916 ◽  
pp. 459-463
Author(s):  
He Quan Zhang
Keyword(s):  
Fluid Mechanics ◽  
Traffic Flow ◽  
Influence Factors ◽  
Traffic Model ◽  
Light Traffic ◽  
The Road ◽  
Model Based ◽  
Light Passing ◽  
Improved Model ◽  
The Impact

In order to deal with the impact on traffic flow of the rule, we compare the influence factors of traffic flow (passing, etc.) into viscous resistance of fluid mechanics, and establish a traffic model based on fluid mechanics. First, in heavy and light traffic, we respectively use this model to simulate the actual segment of the road and find that when the traffic is heavy, the rule hinder the further increase in traffic. For this reason, we make further improvements to the model to obtain a fluid traffic model based on no passing and find that the improved model makes traffic flow increase significantly. Then, the improved model is applied to the light traffic, we find there are no significant changes in traffic flow .In this regard we propose a new rule: when the traffic is light, passing is allowed, but when the traffic is heavy, passing is not allowed.

Educational Homogamy Among Married and Unmarried Couples in Europe

2008 ◽  
Vol 30 (1) ◽  
pp. 28-52 ◽  
Author(s):  
Dana Hamplova
Keyword(s):  
Linear Models ◽  
Married Couples ◽  
European Social Survey ◽  
Social Survey ◽  
Educational Homogamy ◽  
Educational Barriers ◽  
Educational Groups ◽  
Institutional Contexts ◽  
Using Data ◽  
Log Linear

In this article, educational homogamy among married and cohabiting couples in selected European countries is examined. Using data from two waves (2002 and 2004) of the European Social Survey, this article compares three cultural and institutional contexts that differ in terms of institutionalization of cohabitation. Evidence from log-linear models yields two main conclusions. First, as cohabitation becomes more common in society, marriage and cohabitation become more similar with respect to partner selection. Second, where married and unmarried unions differ in terms of educational homogamy, married couples have higher odds of overcoming educational barriers (i.e., intermarrying with other educational groups).

Sign in / Sign up

Export Citation Format

Share Document