The main objective of this paper is to report on unsafe actions of motor vehicle drivers at railroadhighway grade crossings and drivers’ response to installation of a centerline barrier that prevented them from driving around the gates. A comparison of unsafe driver actions in the preand post-barrier periods provided an idea about the effectiveness of the barrier in reducing unsafe driver actio...

Numerous approaches to verifying the safety of vehicles in the AHS architecture of PATH have been proposed (see 1] and 2]). One approach involves nding a boundary between safe and unsafe initial conditions. This task is signiicantly easier if we can guarantee that the severity of an accident is monotonic in the initial conditions. Simulation results are presented in which it is shown that this ...

BACKGROUND Abortions performed by persons lacking the requisite skills or in environments lacking minimal medical standards or both are considered unsafe. It is estimated that over 20 million unsafe abortions are performed annually and about 70 000 women die globally as a result, with the majority occurring in the developing world. This study aims to determine the sociodemographic factors invol...

We give a presentation of Pure type systems where contexts need not be well-formed and show that this is equivalent to the usual one. The main motivation for that, when we extend with computation rules, like in logical framework Dedukti, want declare constants before rules are needed check well-typedness their type.