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This session is a hands-on technical course focused on building a Behavior Diagram (BDD) for a simulation context within a systems engineering modeling environment, likely using SysML or a similar tool. The instructor guides participants through the creation of a simulation context BDD, emphasizing block composition, generalization relationships, constraint block integration, and property inheritance with default values. The session includes live demonstration of modeling techniques, clarification of diagram elements (e.g., directed associations vs. composition), and troubleshooting of interface block typing and proxy port configuration for parametric diagrams. The goal is to reinforce modeling best practices and ensure alignment with component specifications and prior lab work.

Topic (Timeline)

1. Session Start and Break Announcement [00:00:04 - 00:05:09]

Instructor identifies participants (Alaina, Mark, Daniel) and acknowledges Daniel’s progress on prior tasks.
Noted that Daniel is working ahead; instructor decides to take a 10-minute break to allow time for completion and reset.
Screen sharing is stopped; participants are expected to return at 11:10.

2. Introduction to Simulation Context BDD and Diagram Structure [00:05:09 - 00:07:36]

Instructor reintroduces the task: constructing a Simulation Context BDD.
Mentions a provided random number generator script (shared via Zoom chat) as an optional challenge, with no expectation of completion during the session.
Outlines the diagram structure: six regular blocks and two interface blocks within the simulation package.
Emphasizes clean, organized block placement for clarity.

3. Block Relationships: Generalization and Composition [00:07:36 - 00:09:35]

Explains use of generalization (e.g., AMF3F preamplifier → preamplifier → amplifier) and composition relationships.
Highlights that the signal generator is not part of the imaging subsystem via composition, but connected via a directed association because it is a simulation-only tool.
Clarifies semantic distinction: directed association implies usage, not ownership or containment.

4. Constraint Block Integration and BSED Alignment [00:09:37 - 00:12:24]

Instructs participants to reuse constraint blocks created in prior lab work, not create new ones.
Demonstrates dragging and dropping existing constraint blocks onto the BDD to link them to the BSED (Block Structure Definition).
Identifies specific constraints: “generate signal,” “generate noise,” and “generate sine wave.”
Notes technical frustration with non-functional delete key; advises against deleting blocks from containment tree to avoid cascading issues.

5. Interface Block Creation and Property Inheritance [00:13:04 - 00:16:33]

Confirms interface blocks should be newly created, not reused.
Demonstrates how to view and redefine inherited properties via block specification → properties panel.
Shows use of the “redefine” option to override inherited attribute default values (e.g., gain = 15 dB, offset = 0.7).
Explains that default values are sourced from component spec sheets (e.g., AMF3F preamplifier datasheet).
Reinforces that inherited properties (marked with tick) should not be recreated—only overridden with new default values.

6. Proxy Port Typing and Flow Properties in Parametric Context [00:16:39 - 00:19:48]

Raises question about typing of proxy ports on BSED signal generator: currently typed as “real,” but this lacks flow direction.
Discusses that proxy ports on BDDs for parametric diagrams require flow properties to enable directional arrows (in/out).
Concludes that while typing as “real” is currently acceptable for display purposes, proper flow properties must be defined in the parametric diagram context.
Confirms that participants should not recreate inherited values; only redefine defaults for specific instances.

Appendix

Key Principles

Generalization: Use to model hierarchical relationships (e.g., AMF3F preamp → preamp → amplifier); inherit attributes, then redefine defaults.
Directed Association: Use for simulation-only dependencies (e.g., signal generator → imaging subsystem), not composition.
Constraint Reuse: Always reuse constraint blocks from prior labs; avoid duplicating equations or expressions.
Proxy Ports: For parametric diagrams, ensure flow properties are defined to enable directional signal representation, even if initially typed as “real.”

Tools and Techniques

Block Specification Panel: Used to access and redefine inherited properties (not attributes).
Containment Tree: Primary source for dragging/dropping blocks and constraints; avoid direct deletion from diagram if block is needed elsewhere.
Component Spec Sheets: Source for default values (e.g., gain, offset) to override inherited properties.

Common Pitfalls

Mistaking directed association for composition → leads to incorrect modeling of simulation dependencies.
Recreating inherited properties instead of redefining them → causes duplication and inconsistency.
Using untyped proxy ports → prevents proper flow representation in parametric diagrams.

Practice Suggestions

Rebuild the BDD from scratch using only constraint blocks from prior lab.
Verify all inherited properties are redefined with correct default values from component datasheets.
In parametric diagram, explicitly define flow properties for all proxy ports, even if they appear as “real” in BDD.

Ai Assisteed MBSE - greg-nw1v-20241219-025741

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Summary

Overview