DERA Systems Engineering Practices: reference model

This preface is an invitation. It is an invitation to those of us who work in DERA to add to the quality of ideas that are important to the wellbeing of our
organization. It is also an invitation to those outside DERA who read this document and are motivated to assist in its improvement.

The document presents a widely applicable, tailorable system life cycle model that can assist the quality and the success of systems engineering practices
throughout DERA. The model is used as the basis for defining systems engineering practices within the DERA Business Management System.

There are many examples of system life cycle models. They are drawn from experiences in numerous system creation and utilization domains. Many of these
life cycles are formulated to satisfy particular needs, as perceived from particular business or organization viewpoints. In varying degrees they are most
probably correct and effective representations, each serving a distinct purpose.

This document, however, tries to take a step closer to a meta-model, one that can be mapped to many existing system life cycle representations, irrespective
of the system’s nature or intended application. Nevertheless, the non-defence reader may sense unwelcome biases in this document, these are
unintentional (though in a document for DERA they may ultimately be acceptable, even necessary). Identifying these biases could be important and lead to a
better appreciation of, and to improvements in, the field of defence systems.

The model described here contains much that is familiar. Such novelty as is presented relates to the generality of the point of view taken, coupled with the
recognition that systems are mostly created and used in commercially competitive environments in which projects are an important influence.

Nomenclature has presented a problem. The terminology used here is used differently elsewhere; different models, different types of system and different
countries employ the same terms with a wide variation of meaning. Alternatives to the terminology and glossary definitions used in this document are
welcomed.