4,501 research outputs found
Using Deep Networks for Drone Detection
Drone detection is the problem of finding the smallest rectangle that
encloses the drone(s) in a video sequence. In this study, we propose a solution
using an end-to-end object detection model based on convolutional neural
networks. To solve the scarce data problem for training the network, we propose
an algorithm for creating an extensive artificial dataset by combining
background-subtracted real images. With this approach, we can achieve precision
and recall values both of which are high at the same time.Comment: To appear in International Workshop on Small-Drone Surveillance,
Detection and Counteraction Techniques organised within AVSS 201
Dynamics of stable viscous displacement in porous media
We investigate the stabilization mechanisms of the invasion front in
two-dimensional drainage displacement in porous media by using a network
simulator. We focus on the process when the front stabilizes due to the viscous
forces in the liquids. We find that the capillary pressure difference between
two different points along the front varies almost linearly as function of
height separation in the direction of the displacement. The numerical results
support arguments that differ from those suggested earlier for viscous
stabilization. Our arguments are based upon the observation that nonwetting
fluid flows in loopless strands (paths) and we conclude that earlier suggested
theories are not suitable to drainage when nonwetting strands dominate the
displacement process. We also show that the arguments might influence the
scaling behavior between the front width and the injection rate and compare
some of our results to experimental work.Comment: The paper has been substantially revised. 12 papes, 10 figure
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