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OMG System Modeling Language — Open Issues

  • Acronym: SysML
  • Issues Count: 3
  • Description: Issues not resolved
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Issues not resolved

Issues Descriptions

Conform as a Generalization is Incorrect - A View is Not a Viewpoint / 'is a' Does Not Equate to Conform

  • Status: open  
  • Source: Eclectica Systems Ltd ( Nic Plum)
  • Summary:

    A Conform relationship is a generalization between a view and a viewpoint.

    This is semantically incorrect. Assuming that viewpoint is being used in ISO 42010 sense (no stated anywhere within the specification so this is an error if true as the common use of 'viewpoint' is not the same as that in the standard) - a viewpoint is a specification against which a view is prepared (and interpreted). A view is not a viewpoint. What's has effectively been said is that a design that conforms to a requirement document is a requirement document.

    In the reverse sense if I want to define that an oak (tree) is an oak I wouldn't then state an Oak (tree) conforms to a Tree.

    If you need to state the conformance relationship between view and viewpoint SysML provides somewhere a 'satisfy' stereotype.

    The history of the OMG misrepresenting or misunderstanding what a 42010::viewpoint is in their documents over the years is woeful.

  • Reported: SysML 1.5 — Sun, 4 Jun 2023 09:16 GMT
  • Updated: Fri, 14 Jul 2023 20:07 GMT

View is not a Viewpoint

  • Status: open  
  • Source: Eclectica Systems Ltd ( Nic Plum)
  • Summary:

    The View conform Viewpoint relationship is shown as a Generalization. This then states that a View is a Viewpoint which is incorrect. A Viewpoint in ISO/IEC/IEEE 42010 terms is a specification against which a View is prepared and interpreted.

    I suspect that this is another example of a long held error where View was described as an instance of a Viewpoint. It isn’t. This has never been true in the international standard.

  • Reported: SysML 1.5 — Tue, 20 Jun 2023 11:15 GMT
  • Updated: Fri, 14 Jul 2023 20:07 GMT

Risk, Source and Verification Method Are Attributes of Any / All Requirements Not Just an Extended Requirement

  • Status: open  
  • Source: Eclectica Systems Ltd ( Nic Plum)
  • Summary:

    The verifyMethod, source and risk attributes are only available for extended requirements i.e. a straight vanilla Requirement has no associated verification method or risk. This doesn't reflect reality / the actual taxonomy and has nothing to do with the sub-classification of a requirement as physical, functional etc. i.e. these are attributes of the parent Requirement not the child extended requirement. It also then requires that a SE has to subclassify before they can ascribe a risk level or verification method.

    Even looking at the definiton of extendedRequirements this definition has nothing to do differentiation in terms of an ontology - only the means to do things. 'A mix-in stereotype that contains generally useful attributes for requirements'

    It also means that if the SE has a requirement that doesn't fit into the OMG classification schema i.e. none of the existing categories then they cannot easily assign these attributes (e.g. a requirement to conform to a standard isn't a design constraint, isn't functional etc). These common attributes should be present without forcing the SE to subclassify before they are available.

  • Reported: SysML 1.5 — Fri, 26 May 2023 11:10 GMT
  • Updated: Thu, 15 Jun 2023 12:48 GMT