An attribute from the associated PowerSystemResource is used.   This is like reflection into the UML model as one must name the paramter the same as the CIM name of the desired attribute. Such parameters are not important for completely standard models as the relation to the CIM attributes is fixed.  This object is required for user defined models that use attributes already existing on the PowerSystemResource or its derived classes.   Using this class avoids creating new paramter instances (with values) when we already have the values as class attributes of the associated PowerSystemResource.   Standard block models might optinally use objects of this class to convey information about the internals of the standard block.