Abstract: Identifying and classifying intersections according to
severity is very important for implementation of safety related
counter measures and effective models are needed to compare and
assess the severity. Highway safety organizations have considered
intersection safety among their priorities. In spite of significant
advances in highways safety, the large numbers of crashes with high
severities still occur in the highways. Investigation of influential
factors on crashes enables engineers to carry out calculations in order
to reduce crash severity. Previous studies lacked a model capable of
simultaneous illustration of the influence of human factors, road,
vehicle, weather conditions and traffic features including traffic
volume and flow speed on the crash severity. Thus, this paper is
aimed at developing the models to illustrate the simultaneous
influence of these variables on the crash severity in urban highways.
The models represented in this study have been developed using
binary Logit Models. SPSS software has been used to calibrate the
models. It must be mentioned that backward regression method in
SPSS was used to identify the significant variables in the model.
Consider to obtained results it can be concluded that the main
factor in increasing of crash severity in urban highways are driver
age, movement with reverse gear, technical defect of the vehicle,
vehicle collision with motorcycle and bicycle, bridge, frontal impact
collisions, frontal-lateral collisions and multi-vehicle crashes in
urban highways which always increase the crash severity in urban
highways.
Abstract: Many computational techniques were applied to
solution of heat conduction problem. Those techniques were the
finite difference (FD), finite element (FE) and recently meshless
methods. FE is commonly used in solution of equation of heat
conduction problem based on the summation of stiffness matrix of
elements and the solution of the final system of equations. Because
of summation process of finite element, convergence rate was
decreased. Hence in the present paper Cellular Automata (CA)
approach is presented for the solution of heat conduction problem.
Each cell considered as a fixed point in a regular grid lead to the
solution of a system of equations is substituted by discrete systems of
equations with small dimensions. Results show that CA can be used
for solution of heat conduction problem.