What fUML can bring to MBSE?


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This presentation focus on advances on Model Based System Engineering that fUML [1] brings. fUML, better known has Executable UML, provide a formalization of a subset of UML. UML, and with some extensions and adaptations SysML, can now be analysed in a formal way. That was main grief made by researchers.

First part of the presentation illustrates what is now possible by picking ideas from existing tools, notably Alloy [1] and OWL [3]. Following this path will enlighten what still must be done from researchers. It also points out how UML/SysML editors and tools can be enhanced. Indeed in current tools you can modelize activities that are not executable, you can describe Class/Block that cannot be instantiated, and so on.

The second part is about current implementation of previous ideas. It starts with a panorama of tools that can be combined, reused or adapted for the new desired features. For instance, it is possible to generate random instances of a model. Doing so helps to be confident in the model constraints. Moreover details will be given on how Topcased ease or not the integration of such a tool in its suite. For instance, it will be shown how Acceleo and ATL are used, but further details will also be given on how it integrates deeply with Topcased Editors for warnings, quick-fixes and so on.

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What fUML can bring to MBSE?

  1. 1. What fUML can bring to MBSE? Loïc Fejoz
  2. 2. Real models are complex. Syntactical verifications are nice but not enough. More model semantics checking is needed.4th february 2011 Loïc Fejoz 2/19
  3. 3. Ok those are simple examples but you can imagine others...4th february 2011 Loïc Fejoz 3/19
  4. 4. This one could be very trickyas the Generalization is notdrawn on the diagram. 4th february 2011 Loïc Fejoz 4/19
  5. 5. Activities verification is the #1 priority of the group that has written the report called "Executable UML/SysML semantics project report"4th february 2011 Loïc Fejoz 5/19
  6. 6. Your models certainly contain less obvious examples (especially for cross-diagram elements)Remember that not allelements are visible ondiagram. Moreover they arecross-cutting concerns ofdiagrams.4th february 2011 Loïc Fejoz 6/19
  7. 7. fUML brings semantic checking possibility.4th february 2011 Loïc Fejoz 7/19
  8. 8. FUML does not axiomatize all UML. It does not axiomatize SysML, nor OCL. But it can be trivialy extended for those examples. Those formulae are written in Common Logic Format (CLIF) with Process Specification Language (PSL).(buml:Classifier “ZooPackage::SelfContentBlock“)(buml:Property “ZooPackage::SelfContentBlock::subpart“)(buml:ownedAttribute “ZooPackage::SelfContentBlock“ “ZooPackage::SelfContentBlock::subpart“)(buml:aggregation “ZooPackage::SelfContentBlock::subpart“ buml:composite)…(forall (o v f) (if (and (form:classifies “ZooPackage::SelfContentBlock“ o f) (form:property-value o “ZooPackage::SelfContentBlock::subpart“ v f)) (= o v))) 4th february 2011 Loïc Fejoz 8/19
  9. 9. fULM Axiomatization Boolean primitive types axiomatization: (forall (x) (if (buml:Boolean x) Obviously fUML provides (or (= x form:true) axiomatization for primitive (= x form:false)))) types, Classification, activity, etc. (not (= form:true form:false)) … Classification and generalization: (forall (csub csuper o f) (iff (buml:general csub csuper) (if (form:classifies csub o f) (form:classifies csuper o f))))4th february 2011 Loïc Fejoz 9/19
  10. 10. Those formulae may be verified automatically by some provers. Thus models can be formally verified (and shall be).4th february 2011 Loïc Fejoz 10/19
  11. 11. Following slides will list tools and difficulty we have to develop an fUML plugin for Topcased. Time for a plugin !4th february 2011 Loïc Fejoz 11/19
  12. 12. Acceleo MTL The generated Java is nor easy to (unit)test nor easy to call. To few documentations for programmatic use.[template class2clif(clz : Class)](buml:Classifier [clz.clifName()/])[for (gen : Generalization | clz.generalization)](buml:general [gen.specific.clifName()/][gen.general.clifName()/])[/for][for (prop : Property | clz.ownedAttribute)][property2clif(prop, clz)/][/for][/template]4th february 2011 Loïc Fejoz 12/19
  13. 13. We would prefer to use QVT but the ATL implementation is more advance. Not easy to write unit-tests especially when comparing with QVT. Usually we run ATL then MTL but it is not that easy to chain both tool without creating ATL intermediate files. vs QVT4th february 2011 Loïc Fejoz 13/19
  14. 14. This are getting better and easier from version to version. No documentation (again!) but the code of the simple verification made by TopCased editor is easy to read and reproduce. Warnings and errors as feedbacks4th february 2011 Loïc Fejoz 14/19
  15. 15. If we generate warnings it would be nice to propose quickfixes. We were not able to program some! There are stuff missing to do that... Moreover there are no documentation nor existing code. Quickfix? Which quickfix?4th february 2011 Loïc Fejoz 15/19
  16. 16. A little bit of topic but... At one point we tried to extends the SysML activity diagram editor so as to present (some) activities with a different looking. We manage to do it but we violate some access restriction. The code is not written for that purpose and reuse is not made easy. Lots of copyn paste. No documentation nor existing code. Diagram extension4th february 2011 Loïc Fejoz 16/19
  17. 17. As we generate files for external programs, we have build a special builder to generate files on model modification but we also tried to update the model from files content. It is a real nightmare... ResourceSet, Builder and model updates4th february 2011 Loïc Fejoz 17/19
  18. 18. Topcased evolves quite quickly so bugs are quickly corrected. BUT plugins also change to quickly and sometime (most of the time?) it involves incompatible changes. I have code from last summer that do not work anymore. Moreover the freeze period is to short for us to react and test our plugin. Fast! Too fast?4th february 2011 Loïc Fejoz 18/19
  19. 19. Conclusion ● Interesting platform ● Lots of plugins ● Models need more semantic checking ● To few documentation ● Not stable enough ● NIH syndrom (between EMF and core)4th february 2011 Loïc Fejoz 19/19