This question refers to concepts described in the following papers by Peak et al (2007):
Simulation-Based Design Using SysML Part 1: A Parametrics Primer
http://eislab.gatech.edu/pubs/conferences/2007-incose-is-1-peak-primer/2007-incose-is-1-peak-primer.pdfSimulation-Based Design Using SysML Part 2: Celebrating Diversity by Example
http://eislab.gatech.edu/pubs/conferences/2007-incose-is-2-peak-diversity/2007-incose-is-2-peak-diversity.pdf
A Definition View is a representation of a recipe for construction, initialisation, and initial connection ("wiring up") of a hierarchical system of holons (or in the language of the above papers, Composable Objects (COBs) with constraints or - in SysML - Blocks with Ports and FlowPorts, ConstraintBlocks with Parameters, and ValueTypes).
An Instance View is a representation of the value state of a system within a given (additional) value context or at a specific moment in time, consistent with a Definition View, where the additional value context can be explicitly supplied by a Block that includes the Definition as a usage, or it can be implied notationally.
These concepts are similar whether applied to an Internal Block Diagram (IBD) or a Parametric Diagram (PD) (which is a restricted form of IBD).
For examples of the concepts applied to Parametrics diagrams please visit:
In SysML1.0 the Instance View concept was not explicitly supported, although it was indicated through the Figure B.38 - Special Case of Internal Block Diagram Showing Reference to Specific Properties (serial numbers), which leveraged the PropertySpecificType concept in combination with a special additional values compartment in an IBD used to reveal the Property.defaultValue of the attributes of the Blocks of parts, as redefined in the PropertySpecificType to evoke the impression of values specific to a context.
In SysML1.1 the IBD 'values' compartment as been renamed ':values' (with a colon) to better indicate that it shows feature-level information from the type of a Property:
NEWS: MD SysML16 will support the IBD ':values' compartment (see example diagram below) !
SysML1.0 also specified something similar to the Instance View under the concept of a "diagram usage":
'SysML also introduces the concept of a diagram usage. This represents a unique usage of a particular diagram type, such as a context diagram as a usage of an block definition diagram, internal block diagram, or use case diagram.'
The refinement of support in SysML for an Instance View related to a Definition View is a topic under consideration by the OMG's SysML Revision Task Force (RTF).
I explore briefly the pros and cons just some of the ways that offer themselves as possible ways to represent an Instance View. I will attempt to represent Instance Views corresponding to the Definition View shown, namely a children's birthday party with some children blowing up balloons. We want to be able to represent the volume of air in the room, in a child's lungs, and in the balloons at different times (without any detailed physics or anatomy of course).
