ELISA Project Seminar Series focuses on hot topics related to ELISA’s mission to define and maintain a common set of elements, processes and tools that can be incorporated into Linux-based, safety-critical systems amenable to safety certification. Speakers are members, contributors and thought leaders from the ELISA Project and surrounding communities. Each seminar comprises a 45-minute presentation and a 15-minute Q&A, and it’s free to attend.
Title: WHAT-WHY-HOW: A practical model for understanding software requirements
Date: Thursday, July 23, 2026, 7:00-8:00 Pacific / 14:00-15:00 UTC / 16:00 – 17:00 CET
Speaker:
Stanislav Pankevich, Lead Software Engineer at Reflex Aerospace GmbH
How to Attend: Register here in advance to attend for free. And please add the webinar joining details to your calendar from the confirmation email you will receive upon registering
Description:
Software engineering discussions often blur intent, requirements, design, and implementation, reducing clarity and weakening traceability. This webinar introduces a simple but rigorous model, “What-Why-How”, for separating these concerns across the development lifecycle.
Starting from core systems engineering concepts such as users, needs, problems, solutions, systems, and environments, the session frames development as a progression from the problem space to requirements (contract) and then to the solution space. It explains how WHY (user needs), WHAT (formal requirements), HOW (design and implementation), and interface (system boundary) relate, and why mixing them leads to ambiguity.
One key property of the WHAT-WHY-HOW model is its recursive structure: at each level of abstraction, the WHAT-WHY of the next level becomes the HOW of the previous one. Recognizing this recursion helps maintain conceptual clarity, particularly in large, multi-tier projects involving multiple stakeholders and suppliers.
Through practical examples and heuristics, the webinar shows how to distinguish requirements from design, avoid mixed statements in technical writing, define minimal traceable requirements (identifier, statement, rationale), and apply the model consistently across documentation, code, testing, and reviews.
The approach is lightweight and broadly applicable, from system architecture to everyday engineering work. The session is suitable both as an introduction and as a refresher for engineers working with requirements and software systems.
