Final Report: Integrating Systems and Software Engineering Project

The study found that the DAG Chapter 4 and the SEP Preparation Guide were significant advances over previous DoD guidance such as MIL-STD-499. They were less fixed on sequential requirements-first processes, and more accommodating of early and thorough verification and validation of requirements before proceeding into development. They had more explicit support of risk management, of achieving appropriate technology readiness levels, and of addressing the full range of system stakeholders. They explicitly addressed system of systems and family of systems considerations, and emphasized event-based rather than schedule-based milestone commitment points.
However, both documents contain many residues from traditional approaches to systems engineering that confine themselves to physical systems engineering and cause significant difficulties in integration with effective software engineering and human factors engineering practices. Their use of one-to-many “part-of” and “owned-by” relationships in decomposing systems conflicts strongly with the many-to-many “used-by” and service-oriented system decompositions natural to systems with distributed, mobile, and rapidly-evolving software and human elements of systems. Their hardware-oriented approach to reliability, availability, and maintainability leaves serious shortfalls of emphasis with respect to their software and human factors counterparts. Their emphasis on event-based milestones is a step forward from schedule-based milestones, but usually leads to decision events that are heavy on PowerPoint charts and Unified Modeling Language (UML) diagrams and weak on evidence that a system built to these diagrams would satisfy the system’s requirements and be buildable within its budgets and schedules.