In Model-Driven Engineering (MDE), the Unified Modeling Language (UML) 2.0 specification includes a metamodel that defines the language concepts and a user model that defines how the language concepts are represented. In UML 2.0, an important use of metamodel is to provide an integrated semantic framework that every diagram in the user model can be projected as a view of the metamodel. However, most existing UML 2.0 metamodels lack the ability to serve as the basis for unifying different views of a software system. To overcome the shortcomings of the current UML 2.0 metamodel approaches, we developed Operation-Based Multi-Queue Structure-Behavior Coalescence Process Algebra (O-M-SBC-PA), which provides an integrated semantic framework that is able to integrate structural and behavioral constructs. Using O-M-SBC-PA as the metamodel of UML 2.0, each diagram in the user model can be projected as a view of the MDE metamodel.