Computer Science Department, Humboldt-Universität zu Berlin, Berlin, Germany.|Computer Science Department, Humboldt-Universität zu Berlin, Berlin, Germany.|Enterprise Platform and Integration Concepts, Hasso-Plattner-Institute, Potsdam, Germany.|Computer Science Department, Humboldt-Universität zu Berlin, Berlin, Germany.|Computer Science Department, Humboldt-Universität zu Berlin, Berlin, Germany.