Systems Theory Flashcards
Define Systems Theory (in an organisational context)
A powerful means of analysing and improving business processes (systems), identifying system behaviour, and what/whom needs to be controlled.
By modelling the world around us we can start to reason about the behaviour of systems
Reductionism/Analysis and Synthesis
Reductionism/Analysis
— focus on components
— describes the system just by the sum of its parts (excludes interconnectivity)
— hence, is only good for low interdependency, low interconnectivity
Synthesis
— includes the interconnectivity (holistic)
— good for high interdependency (social constructions, ecosystems, computer networks, etc.)
7 system characteristics
- interrelated components working towards a collective goal
- interconnected (no complete isolation)
- can be complex — (sub-systems, supra-systems)
- sub-systems interact by exchanging information via well-defined interfaces
- linkage or coupling between systems varies
- transform inputs into outputs (the system’s function)
- emergent properties
tight and loose coupling
tightly coupled — strong interdependencies (e.g. machinery)
loosely coupled — more independent, less reliance on other components (e.g. postal service)
5 system components
- Input
- Transformation process
- Output
- Feedback mechanism (sensor)
- Control mechanism
More and more technical systems arise because …
(A) cheapening, more capable sensors and
B) increasing ability to network things (Internet, faster computation
What is the STAMP method and why is it useful
Systems Theoretic Accident Model and Processes
- Nowadays, many systems are socio-technical, where many errors occur on both sides.
- An accident or loss is very rarely caused by a single error or failure.
- Systems theory can help us identify what or whom needs to be controlled.
A useful way to analyze accidents, particularly system accidents. In STAMP, systems are viewed as interrelated components that are kept in a state of dynamic equilibrium by feedback loops of information and control.
positive and negative feedback
Positive feedback
• self-reinforcing feedback
• unsustainable (e.g. mass-panic)
Negative feedback
• The act of reversing the discrepancy between desired and actual output. (e.g. central heating system)
• Delays in the feedback can cause oscillations.
What are non-linear sensitivities? + example
Butterfly Effect: serious failures can occur if there are unplanned or uncontrolled interactions between the parts (non-linear sensitivities).
An example is Computer Based Trading (CBT) !!
What are overriding priorities in systems?
- transport system which must be safe
* satellite system which must be reliable
source of constraints
emergent properties
Six Principles for Integrated System Design
- Debate, define, and revise the purpose
- build the business case - Think holistic
- look at all parts + environment + tools and methods
- manage entire timeline - Follow a systematic procedure (aka. the project management guidelines)
- Be creative
- from simple to complex
- success metrics measure how closely the candidate design meets the goal
- trade-offs between requirements and system architecture may occur - Take people into account
- motivation, competence, quality, ergonomics, ethics and trust - Manage the project and the relationships
- design the project, not just the system
- project management
- be agile; collaboration
define a hazard and accident
a hazard can be controlled (food poisoning)
an accident/loss may be outside of our control (food products containing pathogens are sold)
Use the constraints to …
- Design the system (constraints are system requirements)
- Determine what information is needed by the controller
- Write the system tests
draw a simple (closed-loop) feedback loop diagram
input–>controller–>process–>output–>sensor sends back output information to input
(e.g., human seeing car speed, central heating system)
