I started a small github repo to organize all the logos I've been using in my work lately, mainly in conference posters. As it takes a few minutes to extract a vector logo from a pdf, I though other people might benefit too from the result.
You can find them here: https://github.com/steven2358/vectorlogos
As an example, here goes the ICASSP 2013 logo in vector format. Click the image for the SVG file, use Inkscape or any other software to edit/convert.