Syntactic Requirements Uniform syntactic interpretation Everyone looking at a SysML diagram should describe it the same way (using SysML terminology) , including whether it is “legal” SysML (well-formed). Includes SysML: Specification writers Teachers and consultants Model builders Modeling tool builders (terminology = metamodel, translation = instantiating metmodel)

Semantic Requirements Uniform semantic interpretation Everyone looking at a SysML model should get the same idea of how the system is built according to how the model will behave. Includes SysML: Specification writers Teachers and consultants Model builders Analysis tool builders (might overlap modeling tool builders).

Specific Requirements RFP can specify language architecture, eg: Use UML without changing: Anything: Profile + equivalent MOF model + mapping. Replace XMI (MOF interchange) with OWL or RDF (maybe via MOF2RDF). Metamodel: eg, add model theoretic semantics to UML as it is. Concrete classes: Specialize UML (metamodel) from formal language, eg, OWL (eg, “onto behavior”). Some: “Branch” off UML, reusing some, not all of UML. The non-MOF subset: Replace MOF subset of UML with OWL.