"I'm glad you recognize the importance of the Semantic Model. I have been a user of the semantic modeling approach for more than twenty years now, and have even created a specialized semantic modeling language, the Constellation Query Language…"
I have developed a Semantic Modeling Language called the Constellation Query Language. It derives from NIAM, ORM2, and related fact-based languages. The language is powerful enough to replace UML class diagrams, OCL, and SQL, but is readable without training (a restricted natural language). Being fact-oriented, it's also attribute-free, so avoids the most common modelling pitfalls of O-O and ER modeling.
My experience of Model Driven Software Development: