Guys, can you elaborate on two-level modeling a little bit?
Is it the same as “model-driven architecture” or not?
By model-driven architecture, I mean systems that could be configured with model metadata. Or there are more than this in “two-level modeling”?
I read couple of papers by Thomas about two-level methodology and still didn’t get it. I have some background in semantic web/ descriptive logic, fhir and v3/rim, ddd, model-driven arch, oop and fp etc 
I probably can repeat claims from papers, but i really didn’t get it. Help me 
I think this section within the openEHR specifications provide some good information on this question: Architecture Overview
Read on Object Constraint Language and its use cases in addition to Birger’s suggestion, then take a look at ADL specifications.