65 research outputs found
Tripwire Detection for Landmines
Pre-processed Radon transform-based detection methods were identified as the most viable technique. There are some issues that arose when testing the various methods. A) The 'log' edge detection in Matlab seemed better than the default 'sobel' method, but is still worth considering other edge detection algorithms that might deal more effectively with noisy or grainy image. B) The algorithm works best when the wire is horizontal and spans the length of the image. If constrained to thin-strip type images then a simple solution is to run the algorithm twice, once with the image and a second time with the same image rotated through 45 degrees
An inverse Gaussian plume approach for estimating atmospheric pollutant emissions from multiple point sources
A method is developed for estimating the emission rates of contaminants into
the atmosphere from multiple point sources using measurements of particulate
material deposited at ground level. The approach is based on a Gaussian plume
type solution for the advection-diffusion equation with ground-level deposition
and given emission sources. This solution to the forward problem is
incorporated into an inverse algorithm for estimating the emission rates by
means of a linear least squares approach. The results are validated using
measured deposition and meteorological data from a large lead-zinc smelting
operation in Trail, British Columbia. The algorithm is demonstrated to be
robust and capable of generating reasonably accurate estimates of total
contaminant emissions over the relatively short distances of interest in this
study
An efficient parallel immersed boundary algorithm using a pseudo-compressible fluid solver
We propose an efficient algorithm for the immersed boundary method on
distributed-memory architectures, with the computational complexity of a
completely explicit method and excellent parallel scaling. The algorithm
utilizes the pseudo-compressibility method recently proposed by Guermond and
Minev [Comptes Rendus Mathematique, 348:581-585, 2010] that uses a directional
splitting strategy to discretize the incompressible Navier-Stokes equations,
thereby reducing the linear systems to a series of one-dimensional tridiagonal
systems. We perform numerical simulations of several fluid-structure
interaction problems in two and three dimensions and study the accuracy and
convergence rates of the proposed algorithm. For these problems, we compare the
proposed algorithm against other second-order projection-based fluid solvers.
Lastly, the strong and weak scaling properties of the proposed algorithm are
investigated
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