Complex Systems Modeling in fmdtools

Agenda and Format

• Introduce characteristics of more complex models

• Overview of how fmdtools modeling classes let us represent these characteristics

  • Classes that represent this complexity

  • Example usages

What makes a system complex? {.smaller}

The broader socio-technical system:

• Interactions between Operators, the physical system, and the Environment

• Example: Pilot (operator) controls the aircraft (physical system) through the airspace (environment)

• Safety is a result of safe interactions!

How fmdtools can represent complexity

Some Notes on Architectures {.smaller}

• Architectures are an extension of the FunctionArchitecture idea covered in Intro_to_fmdtools.md

• Architectures are just agglomerations of Blocks (Functions, Flows, or Components) and can include:

  • FunctionArchitecture: Functional behaviors and their interactions

  • ComponentArchitecture: Physical Components fulfilling function(s)

  • ActionArchitecture: Logical sequence of operational tasks

  • GeomArchitecture: Physical geometries in a shared space

These all have different use-cases–not all work as top-level models.

Example: ComponentArchitecture

Can be used to represent different sets of components fulfilling a given function.

Code Templates: See src/fmdtools/define/block/component.py and src/fmdtools/define/architecture/component.py

Example: Different Propulsion Architectures in a Drone, see: examples/human_hazard_mitigation.model_main.py

Human Actions, Perceptions, and Communications

• Important aspects of operator behavior

• Also relevant to Autonomous Systems

Action Architectures {.smaller}

Can be used to represent different sets of actions performed in sequence or under different conditions, creating a structure like:

Code Templates: See src/fmdtools/define/block/action.py and src/fmdtools/define/architecture/action.py

Examples:

• Human operator choosing to mitigate hazards: examples/human_hazard_mitigation/model_main.py

• Human-operated rover: examples/navigating_rover/model_human.py

• Human-operated cooling tank: examples/cooling_tank/model_main.py

Perceptions - MultiFlow {.smaller}

• Extends concept of flow with multiplicity - meaning local copies of shared variables can be created to represent perceptions of these variables.

• See: src/fmdtools/define/flow/multiflow.py

Example: State communication demo model: examples/state_communication.model_main.py

Communications - CommsFlow {.smaller}

• Provides communications “network” for passing information between agents

• See: src/fmdtools/define/flow/commsflow.py

Example: State communication demo model: examples/state_communication.model_main.py

Characteristics of Environments

• Needs to be broadly shared and perceived/communicated (note that Environment class is descendent of CommsFlow)

• External dynamic conditions (can be represented with a Function)

• Geospatial static and dynamic properties such as:

  • Terrain, temperature, pressure, etc. (See Coords). See code tempaltes at src/fmdtools/define/object/coords.py

  • Usable infrastructure like roads or runways and airports for airplanes (See GeomArchitecture). See code templates at src/fmdtools.define/object/geom.py and src/fmdtools/define/architecture/geom.py

Put together into a single Environment class, see src/fmdtools/define/environment.py

Integrated Architecture Examples

• airspacelib Contingency Management Model (Coords+GeomArchitecture): examples/airspacelib/contingency_management/model_environment.py

• Line-following rover (GeomArchitecture): examples/airspacelib/navigating_rover/model_main.py

• airspacelib Water Rescue Model (Coords): examples/airspacelib/water_rescue/model_environment.py

• Multirotor Drone (Coords): examples/multirotor_drone/model_urban.py

• Rover representing exploration (Coords): - Line-following rover (GeomArchitecture): examples/airspacelib/navigating_rover/model_troupe.py

Conclusions and Tips

• Not every “complex system” model needs every construct

• The goal of a simulation should always be representing what is needed for analysis, not every conceivable aspect

• The fmdtools library has many different modeling constructs for this!

As models become more complex, it becomes more and more important to follow our Best Practices