Structure of Complex Systems (Types of Environmental Interactions …
Structure of Complex Systems
It describes the different ways in which a system interacts with other systems and its environment in general. it helps to:
communicate the boundaries of systems.
A context diagram consists of three basic elements
Interactions between the external entities and the system are represented by arrows. Arrowheads represent the direction or flow of a particular interaction.
It is an oval, circle, or rectangle in the middle of the context diagram
Only the name of the system is written within.
This is the single geographic figure.
These constitute all entities the system will interact with.
mainly sources for inputs and
destinations of outputs from the system
External and Internal Interfaces
at the boundaries between the system and other external entites
between individual components within the system
A major theme of systems engineering is management of interfaces through:
Identification and description
concept definition phase
coordination and control
engineering development, production
Communication between two or more elements in a system. Interactions are effected through the interface connecting the interacting entities.
Physical interface/interaction initiates functional interaction e.g.
[Traction rate/Velocity] Vs [tires of the car on the road]
[Car's travel directions] Vs [driver's hands on the steering]
Functional interactions and physical interfaces
Isolaters: Inhibit such interactions; and
Converters: Alter the form of the interaction medium
Connectors: Facilitate transmission of electricity, fluid, force etc between components
Basic Interaction media
Types of Environmental Interactions
Indirect non-functional interactions such as:
ambient temperature, Pressure, wind
external sound etc
Direct interaction with the system's primary functions
controls (human control interface/autonomous control)
Functional Interaction (Primary) Environmental
[A passenger aircraft]
[Inputs and Outputs]
Primary function: to transport passengers and their belongings
Passengers and their luggage
Flight Control and guidance
Inputs and Outputs
Primary function: to cater for academic related activities
Guest Lecturers etc
Operational Maintenance: System readiness and operational reliability during the operating life.
access for monitoring
Secondary Interaction/Non-functional Environmental
Infrastructure to support system's mission
provides protection from temperature, humidity, and other external factors.
can occasionally constrain performance if not compatible
Shipping and Handling Environment. Transportation from the manufacturing site to the operating site
Shocks and vibrations
Threats: This class of external entities can be man-made or natural.
Corrosive salt water environment for offshore engineering systems, naval fleets
System threats need to be identified early to design counter measures into the system.