1. The Engineering Design of Systems: Models and Methods 3rd Edition
Chapter 3 – Modeling and Process Modeling
By Dennis Buede and Bill Miller
Innovative Decisions, Inc.
Chapter 3 - Modeling and Process Modeling

2. Chapter 3 - Modeling and Process Modeling
Models
Incomplete representation of reality
Answers questions
Types of questions
Definitional
Descriptive, predictive
Normative
Chapter 3 - Modeling and Process Modeling

3. Taxonomy of Models Model Categories Model Subcategories
Typical Systems Engineering Questions
Physical
Full-scale mock-up
Subscale mock-up
Breadboard
How much?
How often?
How good?
Do they match?
Quantitative
Analytic
Simulation
Judgmental
Qualitative
Symbolic
Textual
Graphic
What needs to be done?
How well?
By what?
Mental
Explanation
All of the above!
Chapter 3 - Modeling and Process Modeling

4. Chapter 3 - Modeling and Process Modeling
Modeling Languages
Semantics: signs and symbols
Syntax: way in which signs and symbols are put together
Chapter 3 - Modeling and Process Modeling

5. Chapter 3 - Modeling and Process Modeling
SysML Modeling
meta-system modeling with use case and associated sequence diagrams as well as requirements relations with requirements diagram,
behavior modeling of the system’s activities or processes (including both static and dynamic modeling) using activity and state machine diagrams,
structural modeling of the system’s components including block definition and internal block diagrams,
parametric modeling of performance characteristics of the system.
the process and structure of that the systems engineering team is taking using package diagrams.
Chapter 3 - Modeling and Process Modeling

6. Comparison of SysML to Traditional SE Modeling Techniques
Chapter 3 - Modeling and Process Modeling

7. Chapter 3 - Modeling and Process Modeling
Use Case Diagram
Chapter 3 - Modeling and Process Modeling

8. Chapter 3 - Modeling and Process Modeling
Sequence Diagram
Chapter 3 - Modeling and Process Modeling

9. Chapter 3 - Modeling and Process Modeling
IDEF0
Genesis: Air Force’s Integrated Computer-Aided Manufacturing (ICAM) program
Variation of Structured Analysis & Design Technique (SADT), SofTech - David Ross
ICAM Definition originally
Integrated Definition 0 in 2012
Chapter 3 - Modeling and Process Modeling

10. IDEF0 Semantics & Syntax
Model
Semantics: Collection of pages
Syntax: Hierarchical structure
Page
Semantics: Boxes and arrows
Boxes: Functions, processes, activities
Arrows: Flow of material or data
Inputs enter from left
Controls enter from top
Outputs leave from right
Mechanisms enter from bottom
Syntax: Interaction of functions via material & data
Transforms inputs into outputs
Using guidance of controls
As performed by mechanisms
Chapter 3 - Modeling and Process Modeling

11. Chapter 3 - Modeling and Process Modeling
IDEF0 Model
Answers definitive questions about the transformation of inputs into outputs by the system
Establishes the boundary of the system on the context page. This boundary is explicated, if needed, as a meta description.
Has one viewpoint; the viewpoint is the vantage or perspective from which the system is observed.
Is a coordinated set of diagrams, using both a graphical language and natural language.
Chapter 3 - Modeling and Process Modeling

12. IDEF0 Rules & Guidelines
Conservation of inputs, controls, outputs & mechanisms
Every function has a control and output
Guidelines
3 to 6 functions per page arranged diagonally
Control-oriented functions placed at top left
Major output functions placed on bottom right
Arcs & functions are decomposable
Feedback is defined by arcs moving from bottom right to top left
Chapter 3 - Modeling and Process Modeling

13. Chapter 3 - Modeling and Process Modeling
Arrow Semantics
Chapter 3 - Modeling and Process Modeling

14. Feedback Semantics of Functions
Chapter 3 - Modeling and Process Modeling

15. IDEF0 Page Structure Chapter 3 - Modeling and Process Modeling
Page Number(s)
Page Content
A - 1
Ancestor or external system diagram
A - 0
Context or system function diagram (contains A0) A0
Level 0 diagram with first tier functions specified
A1, A2, ...
Level 1 diagrams with second tier functions specified
A11, A12, ..., A21, ...
Level 2 diagrams with third tier functions specified
... …
Chapter 3 - Modeling and Process Modeling

16. IDEF0 Functional Decomposition
Chapter 3 - Modeling and Process Modeling

17. Function Flow Block Diagrams
Basic
Series
Concurrent
Selection
Multiple-exit function
Enhanced
Iteration
Looping
Replication
Series
Concurrent
Chapter 3 - Modeling and Process Modeling

18. Selection & Multiple-exit Functions, Iteration, Looping in FFBD
Chapter 3 - Modeling and Process Modeling

19. Chapter 3 - Modeling and Process Modeling
Selection, multiple-exit functions and inputs/outputs between functions in an EFFBD
Chapter 3 - Modeling and Process Modeling

20. Chapter 3 - Modeling and Process Modeling
Selection, multiple-exit activities and inputs/outputs between activities in an activity diagram
Chapter 3 - Modeling and Process Modeling

21. Semantic Elements of a Block Definition Diagram
Chapter 3 - Modeling and Process Modeling

22. Block Definition Diagram
Chapter 3 - Modeling and Process Modeling

23. Semantic Elements of Internal Block Diagram
Chapter 3 - Modeling and Process Modeling

24. Internal Block Diagram
Chapter 3 - Modeling and Process Modeling

25. Chapter 3 - Modeling and Process Modeling
Semantic elements for the block definition diagram used for performance modeling
Chapter 3 - Modeling and Process Modeling

26. Block Diagram for Fundamental Objectives
Chapter 3 - Modeling and Process Modeling