There was a YouTube video of it and I've been searching for it forever. Anyone know what I'm talking about? The technology in Africa wasn't ultrasonic but it worked and was compatible with people's phones and ATMs. You could make a mobile payment in the middle of nowhere and then play that payment back to the ATM and it would give you cash. The system at the time was amazing, especially since it was directed at the 3rd world. If you've seen what I'm talking about please post a link. I've been dying to show it to a friend in Cape Town.

I thought they were actually reviewing applications over there. What exactly does the approval process achieve?

Patent filed Feb 28th, 2007 by Facebook Announced November 8th, 2006 by Helio GFY Facebook

Miller-Rabin is OK for quick checks but if you're really desperate to prove that a number is prime there's a decently fast test (relatively) called the AKS primality test. http://en.wikipedia.org/wiki/AKS_primality_test

Don't regulate the peak volume, regulate the RMS volume or some other form of rolling average.