Systems Engineering

After finishing my 15 page marathon take-home exam in Intro to Systems Engineering you would think I've had enough of it -- and you would be wrong! I thought that now that my brain is full of systems engineering that it would a great time to write up exactly what I think it is.

The big caveat is that I am not a practicing systems engineer. I've spent almost my entire career as a consultant working on small team software projects. I started this degree program (technical management) as a stepping stone ffor working on larger scale projects, culminating in creating my own software product. I'm obviously half way through my class so I think now is a great time to gather my thoughts which I'm sure will evolve greatly as I start applying them when I return to work in May.

A complex system is one with diverse elements having intricate interrelationships. (Kossiakoff pg. 3) The text provides a three point criteria for a system that would need systems engineering:

1. Engineered product that satisfies a specific need
2. Contains diverse components with intricate interrelationships requiring multiple engineering disciplines.
3. Advanced technologies are used in fundamental ways to meet the system goal

SpaceShipOne, winner of the Ansari X PRIZE, is a perfect example of a complex system. I could probably write a whole post on that but this one is getting long so take my word for now.

In order to understand what systems engineering is we also need a conceptual framework for how a complex system is developed. Kossiakoff and Sweet presents a conceptualized systems engineering lifecycle that shares transitions with DoD 5000 phases, ISO/IEC 15288 stages, and NSPE stages.

Concept Development	Needs Analysis	Concept Exploration	Concept Definition
Engineering Development	Advanced Development	Engineering Design	Integration & Evaluation
Post Development	Production	Operation & Support

He divides the life cycle into 3 stages, each comprised of phases. The names indicate the primary activities performed in that part of the process. In the concept development stage the focus is on conceptually defining the system to meet validated customer needs. In engineering development this concept system is translated into a validated physical system design that satisfies the triple constraints of cost, schedule and scope (requirements). Post development stage is the actual construction of the deliverable system and its operation/support. Each of these phases are usually formal decision points for the development of the system with costs and risk impact increasing in each phase reaching a peak resource commitment during production. At each phase the documentation and design representations become more detailed and complete.

The system engineering method is the “systematic application of the scientific method to the engineering of a complex system.” (Kossiakoff pg. 69) Kossiakoff proposes a four step process that conceptualizes the set of activities that repeat from one life cycle phase to the next.

The first step is Requirements Analysis or problem definition. Functional Analysis and Allocation as the second step helps ensure a disciplined approach to effectively organizing functions while allowing for a configuration of functions that best balances the desired characteristics of the system. Third, Physical Definition is “the translation of the functional design into hardware and software components, and the integration of these components into the total system.” (Kossiakoff pg. 75) The final step is Design Validation (also called verification or evaluation) which is an explicit validation of the design through modeling, testing and test data analysis.

Each of these four steps are applied over each phase of the system life cycle. While the steps are the same, the focus shifts in the phases as the system materializes from system-level in the needs analysis to component and parts level in the engineering design phase.

Applying the systematic approach of the system engineering method to each phase in the system life cycle results in a process that takes abstract needs and maps them to a set of actual components. These components are integrated into a system to perform complex functions to realize those needs. This process is called System Materialization.

System Materialization starts at the highest level called the system level. All the subsystems are visualized and the operational objectives of the system are defined in the needs analysis phase. Each phase visualizes the next level down in terms of the system design hierarchy as depicted in Table 3-1 from the book with the shaded areas indicated the primary focus of that phase.The current state of system definition at any point in the life cycle is the current system model.3 Even early on a general vision of the physical embodiment of the system is essential, though this vision may differ radically from the fully materialized system.

This process of systematically bringing a complex system from customer need to delivered product requires a disciplined approach in order to meet cost, time and requirements. Systems engineering provides a systematic method for managing the complex technical issues involved. Closely related is the project planning and control aspect (but since I haven't had that class I will not comment for now).