View MODAF:SV-4 Functionality Description View
Overview
The SV-4 Functionality Description View is part of the MODAF System Viewpoint and one of the 46 MODAF views*.
Version & Date
p>Version 1.2.004.
+ = new at 1.2.004
The change history is derived from the definition of each MODAF view within the The MODAF System Viewpoint
viewpoint defining document from www.mod.uk/modaf.
Purpose*
From The MODAF System Viewpoint (SV)
p24:
An SV-4 specifies the functions carried out by all types of Resource, including organisational resources.
Subject to Crown Copyright
Background
From The MODAF System Viewpoint (SV)
p24:
The primary purposes of the SV-4 are to:
- Develop a clear description of the necessary data flows that are input (consumed) by and output (produced) by each resource.
- Ensure that the functional connectivity is complete (i.e. that a resource’s required inputs are all satisfied).
- Ensure that the functional decomposition reaches an appropriate level of detail.
The Functionality Description provides detailed information regarding the:
The SV-4 is the systems view counterpart to the Activity Model (OV-5).
Subject to Crown Copyright
Description
From The MODAF System Viewpoint (SV)
p25:
The SV-4 is used to specify the functionality of resources in the architecture. SV-4 is the functional counterpart to the structures specified in SV-1, Resource Interaction Specification, (in the same way that OV-5 is the functional counterpart to OV-2, Operational Node Connectivity Description).
The scope of this view may be capability wide, without regard to which resources perform which functions, or it may be resource-specific (usually with the resources depicted as swimlanes). There are two basic ways to depict SV-4:
- The functional hierarchy shows a decomposition of functions depicted in a tree structure and is typically used where tasks are concurrent but dependent, for example, on a production line.
- The functional flow diagram that shows functions connected by data and control flow arrows.
The functional hierarchy approach may be particularly useful in capability-based acquisition where it is necessary to model the functions that are associated with particular capability configurations depicted in the SV-1.
Subject to Crown Copyright
Data Objects
From The MODAF System Viewpoint (SV)
p24:
The data in an SV-4 can include:
Subject to Crown Copyright
Presentation*
From The MODAF System Viewpoint (SV)
p24:
- Topological (connected shapes)
- UML activity diagram
- UML activity diagram (with swimlanes)
- Class / block definition diagram+
- Composite structure / internal block diagram+
- SysML activity diagram
- N-squared table
A graphical variant of the SV-4 data flow view may be used with
swimlanes. A system swimlane may be associated with a resource, for example a system, a capability configuration (usually based on a physical asset) or a role.Swimlanes are presented either vertically or horizontally. A function is placed in the swimlane associated with the resource that it is allocated to in the solution architecture. This provides a graphical means of presenting the interactions between systems or capability configurations (shown through system connections on SV-1) in functional terms. This is a powerful technique for visualising the differences between alternative solution options (which may have a common set of functions).
Subject to Crown Copyright
Configuration History
- 1.2.004 adds class/Block definition diagram and composite structure/internal block diagram as presentation methods
Comments
For something that focusses on function it is odd that the description focusses on necessary data flows
. This perhaps reflects the priorities of the originating body which manages procurement rather than a needs of a systems engineer - an interface/supplier dependency rather than a design motive.
References
- The MODAF System Viewpoint (SV). 26th April 2010. https://www.mod.uk/DefenceInternet/AboutDefence/CorporatePublications/InformationManagement/MODAF/TheSystemViewpointsv.htm
Other Frameworks
See also:
- DNDAF::SV-4 Systems Functionality Description Subview
- DODAF::SV-4 Systems Functionality Description Model (deprecated in favour of DODAF::SvcV-4 Services Functionality Description Model)
- NAF::NSV-4 System Functionality Description Subview
- NAF::SVp-04 Solution Function Viewpoint
Category:Framework -> View
Category:MODAF -> View
Category:Solution