Preface Systems engineering is a multidisciplinary approach for developing solutions to complex engineering problems. The continuing increase in system complexity is demanding more rigorous and formalized systems engineering practices. In response to this demand, along with advancements in computer technology, the practice of systems engineering is undergoing a fundamental transition from a docu- ment-based approach to a model-based approach. In a model-based approach, the emphasis shifts from producing and controlling documentation about the system, to producing and controlling a coherent model of the system. Model-based systems engineering (MBSE) can help to manage complexity, while at the same time improve design quality and cycle time, improve communications among a diverse development team, and facilitate knowledge capture and design evolution. A standardized and robust modeling language is considered a critical enabler for MBSE. The Systems Modeling Language (OMG SysMLÔ) is one such general-purpose modeling language that supports the specification, design, analysis, and verification of systems that may include hardware, software, data, personnel, procedures, and facilities. SysML is a graphical modeling language with a semantic foundation for representing requirements, behavior, structure, and properties of the system and its components. It is intended to model systems from a broad range of industry domains such as aerospace, automotive, health care, and so on. SysML is an extension of the Unified Modeling Language (UML), version 2, which has become the de facto standard software modeling language. Requirements were issued by the Object Management Group (OMG) in March 2003 to extend UML to support systems modeling. UML 2 was selected as the basis for