From need to implementation: key aspects of systems engineering

This fact sheet presents the BEH (requirements by heuristic study) method, which assembles a series of classic systems engineering tools to achieve a precise and exhaustive definition, from requirements to functional decomposition, and culminates in project planning and implementation by component.

The method presented here breaks down the analysis into thirteen steps:

• brief description of the four aspects of the requirement;

• open and detailed analysis using seven questions (CQQCOQP for How?, Who?, What? How much?, Where?, When?, Why?) in a search for SMART answers;

• integration into a list of the strongest components;

• detailed description in CQQCOQP of components ;

• for each component, functional analysis in terms of main functions or objectives ;

• for each component, functional analysis in terms of constrained functions or constraints ;

• prioritization of objectives and constraints and extraction of representative project objectives and constraints ;

• drafting of the project scope memorandum ;

• project risk analysis on main objectives ;

• detailing objectives using the SMART approach and drafting the technical specification of requirements (STB) ;

• breaking down objectives and constraints into elementary tasks ;

• tree structure and drafting of OTT sheets for each elementary task ;

• breakdown of objectives and constraints into unit components, and links with the STB and qualification procedures for each design stage, from the component to the overall system.