Moving From System Specification to Software Development

Systems engineering is not about developing electronics, mechanical, or software designs. Systems engineering is really about four things:

• Creation of system requirements that meet stakeholder needs;
• Identification of a system architecture;
  
• Allocation of requirements into the system architecture;
  
• Handing off subsystem-level specifications to teams responsible for their development.
  

Of course, creating the right requirements involves some deep analysis of safety, reliability, control theory, and often, physics. Identification of architecture usually involves trade studies to evaluate architectural alternatives against various measures of effectiveness.

In a traditional systems engineering environment, the primary medium of exchange is textual documentation, often encompassing hundreds to thousands of pages of text. Text, while wonderfully expressive, has some well-known problems for such specifications, including inherent ambiguity and difficulty in ensuring and maintaining consistency, accuracy, and the right level of fidelity.

Including model-based artifacts (UML or SysML) in the hand-off provides better understandability while simultaneously offering greater precision. It is possible to organize the systems engineering workflow to support both the systems engineering work and to support the hand-off to subsystem design teams.