It checks for price changes every minute, and sends an update if the price change is greater than half a percent. If if fails to run (server down) I get an ale

It checks for price changes every minute, and sends an update if the price change is greater than half a percent. If if fails to run (server down) I get an alert. You could do arbitrate with the Unum Smart Contract the same way you could with an exchange, but true arbitrage opportunities are rare.