[IEEE Fourth Workshop on Model-Based Development of Computer-Based Systems and Third International Workshop on Model-Based Methodologies for Pervasive and Embedded Software (MBD-MOMPES'06) - Potsdam, Germany (30-30 March 2006)] Fourth Workshop on Model-Based Development of Computer-Based Systems and Third International Workshop on Model-Based Methodologies for Pervasive and Embedded Software (MBD-MOMPES'06) - Concepts for Abstracting away Object Reification at the level of Platform Independent Models (PIMs)