Influence of the Primary Suspension Damping on the Ride Comfort in the Railway Vehicles

The paper features the results of a numerical study regarding the influence that the damping reduction in the primary suspension of the rail vehicle, due to the defect in a damper, has on the ride comfort. The study is based on model of rigid-flexible coupled vehicle, with seven degrees of freedom, where the carbody is modelled as an Euler-Bernoulli type equivalent beam. The results of the numerical simulations show the power spectral density of carbody vertical accceleration and the ride index comfort calculated in three carbody reference points - at the centre and against the bogies, for various cases of reduction in the damping constant of the primay suspension in the axle, compared to the reference value. As a function of velocity, due to the geometric filtering effect, the damping reduction has contrary effects upon the level of vibrations in the carbody and upon the ride comfort.

Pedestrian Crowd Detection Based Unmanned Aerial Vehicle Infrared Imagery

Human detection is a keyproblem in computer vision. Recently, some research has been focusing on the detection ofpedestrianusing infrared images. The infrared images have outstanding merit. It depends only on object's temperature, but not on color or texture. In this paper, the pedestrian crowd detection approach is proposed. The approach is compose of ROI blocks extraction and crowd block recognition. ROI blocks can be extracted with circle gradient operator and weighted geometric filtering. Crowd blocks are recognized by support vector machine, which combines histogram of oriented gradient and circle gradient. The experimental results show thatthe approach works effectively in different scenes.