Suggest how an engineer responsible for drawing up a system requirements specification might keep track of the relationships between functional and non-functional requirements?

Answer 1

In software development, these relationships you're trying to make are almost certainly never going to be one-to-one. Without knowing more about your project, I'd say your best bet would be to start by systematically separating your project into sections and to developing the requirements lists around each of those modules.

For each section, once you've got requirements lists drawn out, go through each and decide where (if any) there are any conflicts or dependencies between and within the lists, even if they are minor. Document each extensively, on *both* sides of the conflict/dependency. Redundancy is okay here.

If you need something to present to bosses/professors, displaying the functional and non-functional key points in two columns for each section with directional conflict/dependency arrows between each should be sufficiently simple.