SysML Functional Requirement -- <<satisfy>>

[Luca Luca]

Hello to everyone,

I have a doubt about FunctionalRequirement.

I don't understand why  FunctionalRequirement  has the constraint: "satisfied by an operation or behavior"  (see Table D.3 - Additional Requirement Stereotypes, pag. 216, OMG Systems Modeling Language (OMG SysML™) ).

I would like to link a "use case" with a FunctionalRequirement by the <<satisfy>> relation.   (  "use case" --------- <<satisfy>>----->  FunctionalRequirement).

I can't do that because "use case" is not a behavioral model element.!!!!

I think one can say that  "use case" has to "satisfy"  a particolar "requirement", because a "use case" is a functionality of the system.

Anyone can explain  me where I am wrong?

Is  "satisfied by an operation or behavior"   a strict constraint (of  FunctionalRequirement) or I can't care about it?

Sorry for my bad english.

Thak you in advance.

[Loyd Baker]

Dear friend

I know some folks talk about a usecase as describing system
functionality. i.e., the functions the system must perform. A better way
to think about a Use Case is that it is a tool the 'end-user', not the
'system developer', use to describe the operational activities they want
the proposed system to perform.

The 'system developer' then looks at each use case, and the defined
operational activities for each use case, and defines the top level
system requirements. Next the 'system developer derives the 'system
components" (i.e., hardware, software, man-in-the-loop) that best
accomplish the set of functional requirements'

Therefore, a usecase is related to one or more derived system
requirements (e.g., a functional requirements) using the <<refine>>
relationship.

"use case" --------- <<refine>>-----> "functional requirement"

and

"system component" --------- <<satisfy>> -------------->
"functional requirement"

I hope this help

Best Regards

Loyd

Loyd Baker
3SL, Inc.
1500 Perimeter Parkway
Suite 123
Huntsville, AL 35806
Phone: 256-971-9500
Fax: 256-971-9800
Cell: 256-714-5428

On 10/25/2013 5:42 AM, Luca Luca wrote:
> Hello to everyone,
>
> I have a doubt about FunctionalRequirement.
>
> I don't understand why FunctionalRequirement has the constraint:
> "satisfied by an operation or behavior" (see Table D.3 - Additional
> Requirement Stereotypes, pag. 216, OMG Systems Modeling Language (OMG

> SysML�) ).

>
>
> I would like to link a "use case" with a FunctionalRequirement by the
> <<satisfy>> relation. ( "use case" --------- <<satisfy>>----->
> FunctionalRequirement).
> I can't do that because "use case" is not a behavioral model element.!!!!
>
> I think one can say that "use case" has to "satisfy" a particolar
> "requirement", because a "use case" is a functionality of the system.
>
>
> Anyone can explain me where I am wrong?
>
> Is "satisfied by an operation or behavior" a strict constraint (of
> FunctionalRequirement) or I can't care about it?
>
>
> Sorry for my bad english.
>
>
> Thak you in advance.

> --
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[Remy Fannader]

A taxonomy of requirements should not depend on languages or tools. It would be as if the understanding of systems would be different in English or French.
http://caminao.wordpress.com/how-to-implement-symbolic-representations/requirements/requirements-taxonomy/
Rémy.

[James Towers]

Lloyd,
This approach may include an unnecessary step,as it's possible to derive the 'system components' directly from the Use Cases (or rather allocate the required functionality onto a previously determined architecture of 'system components') since the Use Cases are 'a set of functional requirements'
Regards

James

On 25 Oct 2013, at 16:06, Loyd Baker <loyd....@threesl.com> wrote:

> Dear friend
>
> I know some folks talk about a usecase as describing system functionality. i.e., the functions the system must perform. A better way to think about a Use Case is that it is a tool the 'end-user', not the 'system developer', use to describe the operational activities they want the proposed system to perform.
>
> The 'system developer' then looks at each use case, and the defined operational activities for each use case, and defines the top level system requirements. Next the 'system developer derives the 'system components" (i.e., hardware, software, man-in-the-loop) that best accomplish the set of functional requirements'
>
> Therefore, a usecase is related to one or more derived system requirements (e.g., a functional requirements) using the <<refine>> relationship.
>
> "use case" --------- <<refine>>-----> "functional requirement"
>
> and
>
> "system component" --------- <<satisfy>> --------------> "functional requirement"
>
> I hope this help
>
> Best Regards
>
> Loyd
>
> Loyd Baker
> 3SL, Inc.
> 1500 Perimeter Parkway
> Suite 123
> Huntsville, AL 35806
> Phone: 256-971-9500
> Fax: 256-971-9800
> Cell: 256-714-5428
>
> On 10/25/2013 5:42 AM, Luca Luca wrote:
>> Hello to everyone,
>>
>> I have a doubt about FunctionalRequirement.
>>

>> I don't understand why FunctionalRequirement has the constraint: "satisfied by an operation or behavior" (see Table D.3 - Additional Requirement Stereotypes, pag. 216, OMG Systems Modeling Language (OMG SysML™) ).

[Jack Ring]

As usual Loyd is right on.
What needs to be said as well is that Use Cases should be written regarding the Capabilities the envisioned system must exhibit in order to cause the Effects it is supposed to have on its context and itself. These Capabilities must reflect a necessary and sufficient intervention strategy which, in turn identifies how many of what kinds of Users there are likely to be (yet to be V&V'd).
Accordingly, not until Users are decided can a Use Case be authored on their behalf.
Otherwise you get Use(less) Cases that lead the project down the wrong path.

On Oct 25, 2013, at 8:06 AM, Loyd Baker wrote:

> Dear friend
>
> I know some folks talk about a usecase as describing system functionality. i.e., the functions the system must perform. A better way to think about a Use Case is that it is a tool the 'end-user', not the 'system developer', use to describe the operational activities they want the proposed system to perform.
>
> The 'system developer' then looks at each use case, and the defined operational activities for each use case, and defines the top level system requirements. Next the 'system developer derives the 'system components" (i.e., hardware, software, man-in-the-loop) that best accomplish the set of functional requirements'
>
> Therefore, a usecase is related to one or more derived system requirements (e.g., a functional requirements) using the <<refine>> relationship.
>
> "use case" --------- <<refine>>-----> "functional requirement"
>
> and
>
> "system component" --------- <<satisfy>> --------------> "functional requirement"
>
> I hope this help
>
> Best Regards
>
> Loyd
>
> Loyd Baker
> 3SL, Inc.
> 1500 Perimeter Parkway
> Suite 123
> Huntsville, AL 35806
> Phone: 256-971-9500
> Fax: 256-971-9800
> Cell: 256-714-5428
>
> On 10/25/2013 5:42 AM, Luca Luca wrote:
>> Hello to everyone,
>>
>> I have a doubt about FunctionalRequirement.
>>

>> I don't understand why FunctionalRequirement has the constraint: "satisfied by an operation or behavior" (see Table D.3 - Additional Requirement Stereotypes, pag. 216, OMG Systems Modeling Language (OMG SysML™) ).

[Monte L Porter Jr]

I too have a problem with the spec in that the test case stereotype and its satisfy relationships are only related to activity, sequence and state diagrams.  The use case is a method we use to build our functional requirements.  In a white box mode I want to detail the steps of a test case (much like we are able to do with use cases).  Not considering a use case as a requirement makes me have to crete yet another non-standard stereotype in order to get my model to autogen a test case.

 

VR

Monte Porter

310 The Bridge Street, Huntsville, AL 35806
CSC | phone: 256-799-3408| cell: 256:874-5894 |mpo...@csc.com | monte.p...@us.army.mil

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To: sysml...@googlegroups.com
From: Remy Fannader
Sent by: sysml...@googlegroups.com
Date: 10/29/2013 10:51PM
Subject: [SysML Forum] Re: SysML Functional Requirement -- <<satisfy>>

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[Jack Ring]

Monte, Is your test case about an external stimulus generator as in a piece of test equipment or is it about what the user wants the system to do to certify its own readiness for Fit For Purpose?

As systems get larger and more complex then self-test becomes preferable to test bays, test cases, regression testing, etc. 

In fact it is now possible to include in any system the ability to determine whether the configuration of software code throughout the system is fault-free.

[garyd...@gmail.com]

Monte

The testcase will <<verify>> the requirements so use that connector rather than the <<satisfy>>. If you think about it that seems more logical. An element is created to <<satisfy>> something in the problem space bounded by requirements, the testcase will then <<verify>> that the element fits in the problem space.

 

Gary

[Monte L Porter Jr]

My problem is that I am working at integrating a system of systems - I want to use SysML to design and execute tests and collect artifacts that a group of more than 100 services are working well together from a users perspective.  (command and control systems tend to fail at scale - as do websites:) ).  I want to use a mission thread but like the white box use case as a starting point for my threads.  In SysML speak, my understanding is that the test case is an "add-on" stereotype that can be used to link requirements to activity diagrams, sequence diagrams, and state diagrams but will not help when tryinfg to link use cases to requirements.

 

Thanks in advance

 

310 The Bridge Street, Huntsville, AL 35806
CSC | phone: 256-799-3408| cell: 256:874-5894 |mpo...@csc.com | monte.p...@us.army.mil

-----sysml...@googlegroups.com wrote: -----

To: sysml...@googlegroups.com
From: Jack Ring
Sent by: sysml...@googlegroups.com
Date: 10/31/2013 09:58PM
Subject: Re: [SysML Forum] Re: SysML Functional Requirement -- <<satisfy>>

[Lawrence Mcgovern]

The requirement needs to be an operational requirement because the system function must be based on an operational requirement. Hope this helps.

--

[Darold]

Use Case can be thought of as the cases (ways) that a user interacts with a system to achieve a desired operational result (e.g., use case).  Each is developed by either customers or people experienced with interviewing customers.  Each use case describes what the user (not necessarily human) does (stimulus, can be a set of actions) and how the system responds.  The expectations described by use cases are then used to develop (derive) the system functional requirements and a functional architecture.

 

So your confusion is the order of dependency. e.g., the functional requirements depend on the use cases, e.g., can be derived from use cases.

 

Hope this helps.

 

Regards,

 

Darold K. Smith

PE (Software, Computer, & Electrical Engineering - Inactive)

CSEP (Certified Systems Engineering Professional, INCOSE)

 

903 217-8259

dsmit...@waldar.com

---