View MODAF:SV-4 Functionality Description View

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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.

* =  changed at 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.

See MODAF Release History.

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‚Äôs 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:

MODAF_SV4_simplifiedmm_data_objects_430.gif

Full size:File:MODAF SV4 simplifiedmm data objects.gif

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

 

Other Frameworks

See also:

 

Category:Framework -> View
Category:MODAF -> View
Category:Solution

Categories:

 

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