In the declarer play section there is an article titled " Pattern recognition #1 RSID ", Ruff stuff in dummy. This article is about identifying that same type of dummy (ruffing dummy), but this time from defenders point of view. In several ways it echoes the same concepts, and its a good idea to read that short article as well as this one.
Defence against ruffs in dummy
Get an email with my two biggest secrets for being a better player. — Paul