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Showing 4 results for Gsi


Volume 11, Issue 1 (4-2011)
Abstract

Abstract: Car-Following models are integral parts of capacity analysis, safety research, traffic simulation, and developing advanced vehicle control systems. During the past six decades, various car following models have been developed. GHR is the most well-known stimulus based model, in which the stimulus is the relative velocity of vehicles. In this research, timeto- collision (TTC), as the stimulus, is proposed as a substitute for relative velocity in the GHR model. GHR model is calibrated based on the comprehensive and detailed data gathered in the NGSIM project on I-80 freeway. The Results of GHR model calibration based on the data obtained for the two stimuli indicated that coefficient of determination (R2) increased from 0.233 in the base model to 0.638 in the proposed model. In all, the results indicated that the application of TTC as the stimulus in the GHR model would improve the model's outcome.

Volume 11, Issue 2 (3-2020)
Abstract

In Pahlavi II period, Iranian cinema flourished and domestic cinematographic films rose. Until then, there were many Indian, Arabic and Western films. With regard to the manner of the community and the sale of the film, the process of producing Iranian films went to "film Farsi". It was made at a low level for the general public. an audience that was the result of incomplete economic reforms, cultural and social changes, and the transformation of society into modernity unfinished. In the 1970s, critical films were also made about the situation of the community. Movies like Secrets of the Jenny valley treasure (1973) Ebrahim Golestan, Tangsir (1974) Amir Nadri, Rock trip (1976) Masud Kimiai. in this research, with a content analysis approach, Three sample films, from critical films in the 1970s were reviewed. selected critical films since the 1970s, the critique of modernization, the conflict between tradition and modernity, crisis and identity conflicts reflecting these conflicts in the form of Islamism and inviting and provoking popular upheaval against oppression. The content and elements of storytelling and illustration in these films, as if the incidents of social uprising and rebellion were anticipated before the Islamic Revolution, was predicted.

Volume 16, Issue 5 (11-2016)
Abstract

Different reasons cause traffic oscillation such as: sudden speed drop of leader vehicle. Stop and go traffic commonly observed in congested freeway traffic result in traffic oscillation. When follower driver of platoon receives the last released wave of downstream to upstream in the traffic oscillation, driver makes different reactions proportional to released wave. They result in forming different behavioral patterns and behavior diversion from equilibrium driver. Follower vehicle drivers of platoon make different reactions to receiving wave based on behavior patterns. In this paper, this study employs vehicle trajectory data from Next Generation Simulation (NGSIM) program. Platoons of vehicles identified through a traffic disturbance classify in deceleration and acceleration phase based on driver behavior and hysteresis in traffic oscillation. Driver behavior in deceleration phase lead to congestion classify into four behavioral patterns: under reaction, under constant reaction, over reaction, over constant reaction based on maneuvering errors of follower driver. And also, in acceleration phase based on traffic hysteresis it classifies into two categories: aggressive and timid behavior. In this search, we can study only three driver behaviors: Over Reaction-Timid, Over Constant Reaction-Timid, Under Reaction-Timid because of vehicle trajectories data failure. When follower vehicle in traffic oscillation receives the last deceleration wave lead to congestion, follower vehicle deviates with equilibrium behavior, Newell trajectory, based on driver behavioral patterns. Every car-following model is used to explain the dependency of the follower vehicle trajectory, and its position at time t, to leader vehicle. According to fig.4, if leader vehicle (n-1), moves with constant speed (v), the follower vehicle must move with constant speed (v), too. Spacing between follower and leader vehicles at the time (t) can be changed, but if the freeway was homogenous, the spacing must be constant at approximately Sn; however, it can be varied for different types of vehicles. In this case, all the vehicles are considered as the same type. According to fig 5.a, in the Newell`s model, when a leader vehicle changes its speed from v to v`, the disturbance wave by speed of d^i/τ^i , will be sent to follower vehicle. This process results in an increase in acceleration of follower vehicle. In this model, di, τi are considered constant and independent of speed. According to fig.5.b, these characteristics result in linear relationship between speed and spacing s^i=d^i+τ^iv. Next, neural network models are developed to analyze the relationship between the microscopic parameters and time of two phases. Neural Networks are kinds of mathematical models characterized by a huge parametric space and flexible structure, and also, inspired by human brain neurons. In this article Multi-Layer Perception (MLP) related to free-Forward neural network is used by following the backward error propagation regulation, including 3 different Layers, namely, input layer, hidden layer and output layer. In comparison to more complex neural network structures, the advantage of Multi-Layer perception is its procedure according to universal function approximation. Although by choosing the suitable active Multi-Layer perception function, the direct relationship with the statistical equal model is available, Multi-Layer perception with the active mathematical function may be considered as a general sample of mathematical regression model. There is some progress in different methods that enable the neural network to identify the impacts of input on the changes of output, more precisely, i.e., information measurement theory, partial derivative and etc. Based on three behavior patterns, analysis results present that are most effective two parameters: deceleration wave lead to congestion and stop phase time. increasing deceleration wave results in reducing time between two phases based on over reaction-timid, and results in increasing it based on under reaction-timid and pattern and over constant up reaction – timid. And also, results of stop phase lead to congestion present based on three behavior patterns that increasing stop phase results in increasing time between two phases.
Sh. Heidari, R. Azizinezhad, R. Haghparast,
Volume 19, Issue 6 (11-2017)
Abstract

Tests were done to determine high-yielding and stable durum wheat genotypes. An experiment was set up as a RCBD (Randomized Complete Block Design) with three replications on 17 advanced durum wheat genotypes under rainfed and supplementary irrigation conditions in the cropping seasons of 2011-13. Combined analysis of variance indicated that environment main effect accounted for 70.09% of total yield variation; and effects of genotype and Genotype×Environment Interaction (GEI) accounted for 2.95 and 10.71%, respectively. Results indicated remarkable difference in genotypes response across environments. G×E interaction was analyzed following Additive Main effects and Multiplicative Interaction (AMMI) model. The first two interaction Principal Component Axes (IPCA1 and IPCA2) explained 53.75 and 36.99% of total interaction effects, respectively. Based on the AMMI model, AMMI Stability Value (ASV) and Genotype Selection Index (GSI), genotypes G11, G8, and G14 were selected for all environments. According to the AMMI2 biplot, the G15, G16 and G17 exhibited specific adaptation with rainfed (E1) and irrigation (E2) environments. G3 and G4 displayed specific adaptation with rainfed (E3) environment and G10, G9, G1, and G12 indicated specific adaptability with irrigation (E4) environment. The E3 had high discrimination ability, so, this environment was considered sufficient for making genotypes recommendation. Results of this investigation illustrate that the AMMI stability parameters are suitable for characterizing stable genotypes and that the GSI parameter can detect genotypes with high grain yield and good stability for plant breeding research in durum wheat.

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