MARTE_ — The notion of value is missing the NFP_Declaration domain model Description

The current NFP_Declaration package of the NFP domain model introduces the notion of NFP and NFPType. However, it is missing a relation between these concepts of non-functional property and the concepts of physical quantity and value (expressed in SysML by Value Property / Value Type). One can consider a non-functional property as a kind of physical quantity. These links need to be explicitly stated, which will foster a future alignment with SysML concepts. Proposed resolution: Introduce the meta-classes: ValuePropery and ValueType in NFP_Declaration package and create inheritance links from ValueProperty to NFP and ValueType to NFPType. No impact on the current UML profile.

Proceed as suggested in the issue summary:
• Introduce two meta-classes ValuePropery and ValueType in the NFP_Declaration
package,
• Create an inheritance link from ValueProperty to NFP and ValueType to
NFP_Type,
• Document the meta-classes in Annex F.
The introduction of the ValueProperty and ValueType metaclasses will provide
intermediate definitions that bridge the notions of non-functional property (NFP)
and more general definitions of value and quantity. It is also an opportunity to
reference SysML notions of ValueProperty / ValueType as related concepts.