Systems Engineering Defined

Systems Engineering is an interdisciplinary process that ensures that the customer's needs are satisfied throughout a system's entire life cycle. This process is comprised of the following seven tasks.

1. State the problem. Stating the problem is the most important systems engineering task. It entails identifying customers, understanding customer needs, establishing the need for change, discovering requirements and defining system functions.
2. Investigate alternatives. Alternatives are investigated and evaluated based on performance, cost and risk.
3. Model the system. Running models clarifies requirements, reveals bottlenecks and fragmented activities, reduces cost and exposes duplication of efforts.
4. Integrate. Integration means designing interfaces and bringing system elements together so they work as a whole. This requires extensive communication and coordination.
5. Launch the system. Launching the system means running the system and producing outputs -- making the system do what it was intended to do.
6. Assess performance. Performance is assessed using evaluation criteria, technical performance measures and measures -- measurement is the key. If you cannot measure it, you cannot control it. If you cannot control it, you cannot improve it.
7. Re-evaluation. Re-evaluation should be a continual and iterative process with many parallel loops.

This process can be summarized with the acronym SIMILAR (Bahill and Gissing, 1998).
Source: http://www.sie.arizona.edu/sysengr/whatis/whatis.html