SYSML14 — Addition of derived property notation

The derived property notation was originally included in SysML and removed. This notation is very helpful and should be restored. An example of how this is used can be found in Figure 7.2.1 of the 2nd edition of "A Practical Guide to SysML".

Several notations on features of blocks were left out of the original SysML
submission and addressed by subsequent issues. During the original SysML FTF,
Issue 10381 listed several of these additional notations to be considered. Following is
the original text of this issue originally received October 3, 2006:
Include examples of additional feature notations in the diagram elements table
for Blocks. Examples of UML notations that have not been excluded by SysML
include a "/" for derived features, underline for static features, and optional
visibility characters "+" "-" "#" "~".
Voting on a resolution of this issue was completed by the original SysML FTF on
February 23, 2007, as documented in the SysML FTF final report (OMG document
ptc/2007-03-19). This resolution added the underline notation for static features to
Table 8.1 in the Blocks chapter, but explicitly excluded the additional notations raised
by the issue. From the issue resolution in the FTF report, "After discussion by the
FTF, the “/” notation for derived features and visibility characters "+" "-" "#" "~" are not
being included in SysML V1.0."
This resolution was based on email discussion and a straw poll that occurred on the
original FTF mailing list, in which there was debate as to which of these notations
stemmed from software engineering practices and which belonged in a systems
engineering context.
Experience since then has clearly indicated that systems engineering modelers find
the derived notation useful to indicate properties that can be fully calculated based on
other properties. For example, they can indicate performance measures or other
objective criteria that can be rolled up from subsystems to a higher system level, or to
indicate dependent vs. independent values in a network of constraints. To reflect the uses of this UML notation in SysML models, and the expectation that it
be available even though it was excluded the last time it was directly considered, add
an example of the "/" derived property notation to Table 8.1 in the Blocks chapter.