Newbie question regarding SysML flows in EA

[stereotype]

Sorry about an EA/SysML newbie question:

I have defined a number og SysML blocks, and a number of flows (ItemFlow) between the blocks. For each flow, I want to specify a number of "attributes" - frequency, item size, and a few more, specific to my project. Same set of attributes for all flows, but different values.

I guess that I should somehow use FlowProperty and/or FlowSpecification, but I don't realize quite how to do it...?

Thanks in advance!

[«Midnight»]

Perhaps tagged values?

If this works well perhaps you could create a profile to extend SysML. [I really don't know if you can extend one profile with another. Perhaps someone will enlighten us on this point.]

[Dave.B]

A Flow Specification specifies what data flows between SysML's flow ports, it does not specify when it flows (as far as I have understood it). The behavioural specification of each block should make that clear.

Whilst you could use tags to add extra meta-data to your model, I'm not convinced from what you have said that this would be the right thing to do. For example sequence diagrams can be used to capture timing constraints.

Regards
Dave B.

[stereotype]

Whilst you could use tags to add extra meta-data to your model, I'm not convinced from what you have said that this would be the right thing to do. For example sequence diagrams can be used to capture timing constraints.

Here is some background information: I am modeling a system according to MoDAF*, and in the view "OV-2" I define the operational nodes and their information exchange (on a high level).

In the view "OV-3", there should be a table with details for the information exchanges in "OV-2" - e.g. type of information, frequency/size, security classification, etc.

I was hoping to be able to generate the OV-3 table from the attributes/tagged values of the flows specified in the OV-2.


*) Ministry of Defense Architecture Framework, www.modaf.org.uk

[Dave.B]

Whilst I'm not familiar with MoDAF, my advice would be:

• Describe the data of the flow with a flow specification,
  
• Only add meta-data to describe the characteristics of the flow (e.g. frequency) and/or the flow specification (security classification) that cannot be mined from other parts of the model (since this leads to model maintenance problems that EA cannot help you with).
  

Element tags can be used to capture meta-data (as opposed to transform directives), but I haven't found a direct way of applying a template set of tags to an element, and they do suffer from being second class citizens in the model, which implies that they have an model opacity that can lead to maintenance problems. (You can of course make visible the each element's tag compartment.)

Other techniques for the capture of meta-data include:

• Associated meta-data classes (which can be excluded from the software solution as you wish);
• Sub-classing; which can work in either direction depending upon the modelling approach that you wish to have; e.g. the super class describes some important aspect that you wish to model (e.g. security classification, message type, etc.) and sub-classes add specific data, or the super class has the data and sub-classes constrain the usage (message type, security classification etc.)
• additional class/block/flow-spec. (meta) attributes, which can marked as such with a stereotype (and excluded from the software solution as you wish).

Hope this helps. Any one one got any better ideas?

Regards
Dave B.