Knowledge Management Department, German Research Center for Artificial Intelligence (DFKI) GmbH, Trippstadter Straße 122, Kaiserslautern, Germany;Max-Planck Institut für Eisenforschung, Trippstadter Straße 122, Kaiserslautern, Germany;Computer Science Department, Indiana University, Trippstadter Straße 122, Bloomington, IN