Navair Systems Engineering Guide

The developer should plan and do appropriate tasks to complete this sub-process. Tasks to consider include the
following:

a) Transformation rules, priorities, inputs, outputs, states, modes, and configurations that will influence and affect the other tasks for definition of system technical requirements are identified and defined, as appropriate to each system product. Review concept of operations and elaborate where necessary on describing system behavior, starting
with outputs generated by external systems (modified as appropriate by passing through the natural system environment) which act as stimuli to the system, causing it to take specified actions and produce outputs which are absorbed by external systems. These single threads of behavior are traced from source document statements and cover every aspect of operational performance, including logistical modes of operation, operation under designated conditions, and behavior required when experiencing mutual interference with multi-object systems.

Aggregation of these single threads of behavior is a more or less mechanical process depending on the level of sophistication of tool support supplied with the design decision database. When aggregated, the logical sum of these single threads of behavior represent a dynamic statement of what the system is required to do. In some cases, the word "scenario" is used to describe a single thread of behavior and in other cases it describes a superset of many single threads operating concurrently (INCOSE 1998, 4.2.2.A).

In defining the requisite system behavior within the operating environment(s), transformation rules are important in characterizing a system. A transformation rule is anything that tells a product how to transform one or more inputs into one or more outputs (transform inputs to outputs), or change fro one mode/state/configuration to another given certain conditions to be true (transform from state X to state Y, for example). For example:
- given inputs A and B, produce output C (inputs/outputs)
- do the above only when in XYZ mode (mode/state)
- do the above only when in configuration LMN (configuration)
- convert A to A-prime by using the JKL algorithm (transformation rule)
- when both A and B received at same time, process A first (priority)