Task: Identify Key System Functions
This task defines the key system functions.
Purpose
The purpose of this task is to group the system functions into sub-sets to support the analysis of alternatives during architectural analysis.
Relationships
RolesPrimary: Additional: Assisting:
InputsMandatory: Optional:
  • None
External:
  • None
Outputs
Main Description

The use-case black-box activity diagrams created during functional analysis are reviewed to group the action nodes into key system functions. Possible criteria for grouping system functions are:

  • the system functions are cohesive and/or tightly coupled;
  • the system functions may be realized by a single architectural component;
  • the system functions will be realized by reuse of an existing component (HW/SW);
  • the system functions will be reused within the system; or
  • the system functions address a specific design constraint.
Steps
Select Use-Case Black-Box Activity Diagram
This task will be performed for each use-case black-box activity diagram. Select a use-case black-box activity diagram and perform the following steps.
Identify related system functions
Review the subject activity diagram and identify action nodes that are related. Define a set of key system functions that describe the set of action nodes and establish traceability from each action node to one or more key system functions.
Repeat steps for each use-case black-box activity diagram
Repeat the previous steps for each use-case black-box activity diagram. For each new activity diagram review and refine the list of key system functions and associated action nodes if needed.  Update the traceability record as required, capturing the relationships between action nodes and key system functions.
Capture the Key System Functions
Capture the results of the work completed in the Trade Study Report.
More Information
Guidelines
Tool Mentors

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