Fitbox - A Fault Isolation Toolbox★★Carlos Silvestre Is on Leave from Instituto Superior Técnico/University of Lisbon, 1049-001 Lisbon, Portugal. The Work of Pedro Casau Was Partially Supported by Grants Sfrh/Bd/70656/2010 and the Project Pest-Oe/Eei/La0009/2013 Both from the Fundação Para a Ciência e a Tecnologia. Research by Carlos Silvestre Has Been Supported by Projects Myrg118(Y1-L3)-Fst12-Ssw and Myrg117(Y1-L3)-Fst12-Mkm of the University of Macau.