I loved the paper! The technique its authors present is more elaborated, though: they mix different sounds extracted from nature, such as birds and wind, and allow mixing different streams to create something pleasant to a sysadmin's ears. I liked this paragraph in special:

"Due to copyright limitations on existing natural sound collections, Prof. Couch has spent many hours with a Telinga parabolic nature microphone and Sony DAT or digital minidisc recorder in search of the perfect bird."

Thanks for sharing this paper!