Process Inputs, Outputs and Loops are part of teh steps that are included in the Systems Engineering Process.

Process Inputs 

The customer’s/User’s needs, objectives and requirements in terms of capabilities, measures of effectiveness, environments, and constraints initiate the systems engineering process. A few of the inputs include:

• Customer Needs/Objectives/Requirements
• Measures of Effectiveness (MoE),
• Environments,
• Constraints
• Technology Base
• Output Requirements from Prior Development Effort
• Program Decision Requirements
• Requirements from Specs and Standards
• Laws and Regulations

Requirements Loops
The Requirements Loop serves to refine the requirements and initiate re-evaluation to determine how firm the requirements are for items that prove to be major cost, schedule, performance or risk drivers. Later in the overall process, detailed system characteristics are compared against the established requirements to verify that they are being met. Requirements analysis links with the Functional Analysis and Allocation to form the Requirements Loop of the System Engineering Process.

Design Loop
The Design Loop operates in parallel with the Requirements Loop. Functional interfaces are established and Functional Architectures defined so that physical system configurations can be developed. As concepts are transformed to hardware and software designs, the design characteristics are analyzed against the allocated requirements. Functional architectures and allocations are re-examined and modified if necessary. Some results of the Design Loop may even reflect into the Requirements Analysis necessitating further re-evaluation.

Process Outputs
The output of the System Engineering Process includes a decision database and a balanced system solution. The database documents include:

• the design,
• all the decisions made to arrive at the design,
• defining specifications,
• verification requirements
• traceability of design features to imposed requirements
• constraints
• specifications
• standards

AcqLinks and References:

• SMC Systems Engineering Primer & Guide – Chapter 2
• Military-Standard 499B “Systems Engineering Management” – 23 Aug 1993

Updated: 7/17/2017