> -------- Original Message --------
> Subject: [SysML Forum] Re: Lack of complete Instance semantics in SysML
> From: Laurent L Balmelli <balme
...@us.ibm.com>
> Date: Tue, October 20, 2009 8:49 pm
> To: sysmlforum@googlegroups.com
> Cc: edi
...@SysMLforum.com, sysmlforum@googlegroups.com
> I also would be interested to know more about why this is a huge "design
> flaw". Can you please elaborate Cris?
> The assertion in this thread that "you cannot assign value to constraint
> blocks because there is not instance semantics" is actually not correct.
> In this case, SysML replaces the need for instances by the concept of
> Context-Specific Properties. When this is supported by the tool
> environment, you can assign values to the parameters in constraint
> properties created from the constraint block that are specific (i..e
> local) to its usage. This is much simpler that the concept of creating
> instances and provides the same benefits. There always has been an
> ambiguity in UML between the concept of a role of a classifier and an
> instance. SysML provides a nice middle ground to it. IBM has an
> implementation that will be part of a future tool release, but that we
> already provide it as a service to our customers, in particular in the
> scope of parametric models simulation.
> There is certainly applications that make good usage of instances,
> especially in embedded systems design, but I have not seen so far in this
> thread an example that was not covered by the actual SysML specification.
> Please share your examples, that would be very interesting!
> ----
> Laurent Balmelli, Ph.D (春芽利 楼蘭）
> Manager, IBM's SysML Representative
> Systems and Product Lifecycle Research and Development
> Rational Development & Services, Yamato Software Lab
> 1623-14, Shimotsuruma, Yamato-shi, Kanagawa-ken
> 242-8502, Japan
> Phone: +81 46 215 4868, Cell +81 80 6597 0578
> nsowatsk <nsowa...@cisco.com>
> Sent by: sysmlforum@googlegroups.com
> 2009/10/19 22:10
> Please respond to
> sysmlforum@googlegroups.com
> To
> <sysmlforum@googlegroups.com>, <edi...@SysMLforum.com>
> cc
> Subject
> [SysML Forum] Re: Lack of complete Instance semantics in SysML
> Hi Cris
> Did you send a follow up on the details of the instance semantics in
> SysML?
> Many thanks
> Nathan
> On 15/10/2009 10:51, "Dragos DOBRE" <dobre.dra...@gmail.com> wrote:
> > Hello Cris,
> > I would like to have your opinion about the lack of complete Instance
> > semantics in SysML.
> > Regards,
> > Dragos DOBRE
> > Doctorant - Nancy Université - Université Henri Poincaré
> > Centre de Recherche en Automatique de Nancy - CRAN
> > Faculté des Sciences, BP 70239
> > 54506 Vandoeuvre-lès-Nancy
> > -----Original Message-----
> > From: sysmlforum@googlegroups.com [mailto:sysmlforum@googlegroups.com]
> On
> > Behalf Of edi...@SysMLforum.com
> > Sent: jeudi 15 octobre 2009 02:36
> > To: sysmlforum@googlegroups.com
> > Cc: UMLforum@googlegroups.com
> > Subject: [SysML Forum] Re: Multiple element instances in a deployment
> diagram
> > Hello Paul,
> > The questions you pose conflate modeling language and tool issues, so in
> > my reply I will endeavor to separate the two.
> >> I would like to be able to have multiple instances of an element
> >> (node, device, etc.) in a deployment diagram (for example, multiple
> >> client stations connected to a server).
> > First, we need to clarify that Deployment diagrams are part of the UML
> > language rather its SysML dialect, where SysML is defined as a UML
> > Profile. (For this reason I am cc-ing my response to the UML Forum, so
> > that other UML experts can also contribute to this thread.) In addition,
> > the lack of complete Instance semantics in SysML is a critical language
> > design flaw, which was noted before the language was formally adopted by
> > the OMG, but which has not yet been corrected. (If you want to
> > understand this critical design flaw better, please let me know and I
> > will be glad to elaborate.) On the other hand, the lack of Deployment
> > diagrams in SysML can be viewed as a design virtue rather than a flaw,
> > since deployment relationships (cf. structure-to-structure allocations)
> > can be easily defined in SysML by defining appropriate stereotypes for
> > selected SysML structural elements and allocation dependencies.
> > You are correct that, according to the UML specification, you should be
> > able to define multiple instances of Nodes, Components, or other
> > allowable Classifiers on a UML Deployment diagram.
> >> I am using EA and it, at least, will not let me do so. Is there a way
> to get
> >> around this or do
> >> what I want to do?
> > There is no need for a workaround in Enterprise Architect (EA) since for
> > the most part EA's Instance syntax and semantics comply with the UML
> > specification. I use most of the mainstream UML/SysML modeling tools
> > frequently, including EA, and I just double-checked this capability
> > using EA v. 7.5 Deployment diagrams. It works fine! I suspect you may be
> > confused by, or misusing, EA's "Paste Element" dialog. When
> > copy-and-pasting a Node or other allowable Classifier (non-instance)
> > Element from the Project Browser to the target Deployment diagram, you
> > need to click on the second radio button labeled "an Instance of Element
> > (Object)" rather than the first radio button labeled "as Simple Link".
> > The former will allow you to define multiple instances of a Node or
> > other Classifier, the other will not since it is a reference link, not a
> > bona fide Instance.
> >> I'd also like to represent two (or more) environments separated by
> >> time. These would represent sequential aspects of a workflow (from a
> >> deployment perspective). ...
> > You are correct that chronologically ordering Instance "snapshots" can
> > be a useful way to compare and contrast environments as they evolve over
> > time. Here, however, I suspect you may encounter problems with how EA
> > handles Instance semantics over time, since this is a relatively
> > sophisticated technique.
> > /Cris
> > __________________________________________________
> > Cris Kobryn
> > Editor, SysML Forum
> > mailto:edi...@SysMLforum.com
> > www.SysMLforum.com
> >> -------- Original Message --------
> >> Subject: [SysML Forum] Multiple element instances in a deployment
> >> diagram
> >> From: Paul Ebert <a2ex...@gmail.com>
> >> Date: Wed, October 14, 2009 6:36 am
> >> To: SysML Forum <sysmlforum@googlegroups.com>
> >> I would like to be able to have multiple instances of an element
> >> (node, device, etc.) in a deployment diagram (for example, multiple
> >> client stations connected to a server). I am using EA and it, at
> >> least, will not let me do so. Is there a way to get around this or do
> >> what I want to do?
> >> I'd also like to represent two (or more) environments separated by
> >> time. These would represent sequential aspects of a workflow (from a
> >> deployment perspective). An example might be a sales person on the
> >> road, giving presentations and gathering customer data at customer
> >> sites and then connecting to the home office network at the end of the
> >> day to load the data into an application or to access email. Again,
> >> in this situation, I'll
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