Design Practices in the Beginning
How to Get Started and What Questions to Ask Leadership and Your Team
Deciding What You Want
How to Get Started
"We don't really know the goal when we start. The most serious model shortcoming is that the designer often has a vague, incompletely specified goal, or primary objective. The hardest part of a design is deciding what to design." ..."I came to realize that the most useful service I was preforming for my client was helping him decide what he really wanted." (pg 22-23, The Design of Design: Essays from a Computer Scientist)
"to state why as well as what- causes quicker perception of one's own fallacies and quicker recognition of other viable design alternatives" (pg 82, The Design of Design: Essays from a Computer Scientist)
"Experienced designers often begin by writing down exactly what they know about the user, the user’s purposes of use, and the modes of use. Wise designers also write down explicitly what they don’t know but assume about the user and users." (pg114 , The Design of Design: Essays from a Computer Scientist)
Why Are We Modeling?
Oftentimes the answer from leadership is "we are modeling because there was a requirement for us to have a model". This is not a specific enough answer to guide the team in the right direction and create the right model. If there is no guidance, a good specific fallback would be the scorecard from the Air Force's Memorandum For The Acquisition Enterprise: Guidance for e-Program Designations. While this scorecard is overwhelming and will not be completed by the end of Phase III, your team will understand specific goals to march towards.
This scorecard can be brought into meetings with leadership to hopefully pair down the list of questions and determine where leaderships priorities lie.
Cart Before The Horse: What To Ask Before Beginning MBSE
"Why make the journey at all?
The first question we must ask ourselves concerns what we hope to accomplish by adopting MBSE. The answer to this question has numerous ramifications for how we will choose to make the journey. Answering it involves knowing what we are doing. Are we engaged in process design/improvement, or are we designing products? The answer to that will help us decide whether our journey needs to include developing the ability to connect the model to physics-based analytic models.
Are our designs “clean-sheet” unprecedented efforts? Or are we engaged in the redesign or replacement of existing systems? The answers to those questions impact the way we will gather data and construct our models. These questions bear on why we choose to engage with MBSE at all, and impact the path we will choose for that journey." -Zane Scott
"How will we implement MBSE?
Once we know what we want to do, we can then—and only then—begin to ask how we will implement MBSE. Here, we will want to know how complex the problems and solutions that make up our design space will be. Complexity will make demands on the MBSE process and tooling. Those demands must be met by our process and tools in order to obtain a useful model of our design." -Zane Scott
Evaluating Project Scope
It is generally easy to think about the system in terms of the biggest doll but that is rarely the case.
It is important to communicate with the other model developers creating the adjacent system models to ensure you are using the same framework (model package structure and shared common libraries)
Takeaway: “There is always a bigger doll” so ensure your systems model can be integrated into a larger system-of-systems model.
Cameo/MagicDraw Model Intent
Cameo & MagicDraw softwares are meant to act as the single source of truth for the system.
It is meant to act as a tool used by system engineers to connect data from lower level engineering domains up to leadership.
It is also meant to help aid communication between lower level engineering domains.
When Are We "Done"
How Precise is Good Enough? There comes a point in which there is diminishing return for adding fidelity. The more fidelity is added to the model, the slower the calculations, the more complex the model is to understand, and the model inherently more difficult to use because it becomes cluttered with complex parameters.
Cameo is meant to be simple so leadership can follow along. It is important to define "what is done" so your team doesn't spin their wheels adding unnecesary fidelity.
Modeling The Goldilocks Level of Abstraction
In architecture, it is important to go into the right amount of depth into each topic. Too low fidelity means a poor solution, too high fidelity takes too much time and doesn't necessarily mean a more precise solution.
Start with a low fidelity simulation with only a few inputs and outputs. If a high fidelity simulation is available then only connect a few variables to it and assume the rest of the inputs as default values.
While this may limit the ability of the simulation, it is often more important to keep things simple.
