 | G. Ossimitz: Teaching System Dynamics and Systems Thinking |
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System Dynamics (SD) is a method for describing, modelling and simulating dynamical systems. It was invented by J. Forrester at about 1960 at the Massachussetts Institute of Technology. Main elements of the system dynamics method are:
- distinction between stocks and flows. in system models.
- a special method of notation of systems in "stock-and flow-diagrams"
- a computer language for numerical simulation of dynamical systems on a computer.
The group around Forrester developed the simulation software Dynamo, which is the ancestor of a number of modern simulation languages. Modern system dynamics software products allow the design of system models in a graphical mode as flow diagrams.
"Industrial Dynamics" was the first successful system dynamics modelling and simulation project. In the early 70ies the system dynamics method gained international attention by the world models of Meadows et. al., which were made for the Club of Rome). Today the system dynamics method has an established role in the description and understanding of complex dynamical systems. The system dynamics method is very often used in non-technical contexts (eg. for modelling social or economical systemes etc.)
Moreover, the system dynamics method has become closely related to ideas of systemic thinking. Sometimes "systemic thinking" and "system dynamics modelling" are used almost synonymous. E.G. the system dynamics Software STELLA is an acronym for Systems Thinking Experimental Learning Laboratory with Animation.
SD-education is concerned with issues of modelling and simulation of dynamical systems in different fields of our life.
- For some researchers certain thematical topics are in the core of interest.Schecker et al (Bremen, Germany) deal with system dynamics models in physics education.
- Especially in the USA there are efforts to establish systemic thinking as an cross-curricular teaching principle. (e.g. in theSTACIN-Project or theCC-STADUS-Project).
- Most of the educational issues are focussed around a certain system-dynamics softwar product; like the Collection of STELLA-Models of B. Gotwals.
- A more psychologically oriented approach is being undertaken by a group of German cognitive psychologists (like Dietrich Dörner). They deal with the question, whether working with computer simulations of dynamical systems can give clues about our thinking and learning of complex situations.
"Systems thinking" (or "systemic thinking") is a very popular phrase - but how can it be defined or measured? It is used
in various contexts:
- System Dynamics modeling and simulation is often the background of a systemic thinking apporach - especially in educational projects.
- Systems thinking has become a manangement and organizational developemement paradigm.
Barry Richmond discusses in his paper "Systems thinking: critical thinking skills for the 1990s and beyond" seven systems thinking skills:
- dynamic thinking: seeing patterns, not only events
- closed-loop thinking: interrelated processes instead of of one-way relations;
- generic thinking: seeing generic structures beyond specific symptoms;
- structural thinking: thinking in stock and flow structures;
- operational thinking: "a milk production systems should include cows";
- continuum thinking: finding ways between the "black and white" extremes;
- scientific thinking: making things quantifyable and testable.
For my empirical investigations about the developement of systemic thinking I have tried to give a workable definition of "systemic thinking". "Systemic thinking has four main dimensions":
- thinking in (explicit) models: Model-building and distinguishing between reality and models is a central dimension of systems thinking.
- thinking in feedback loops and interrelated structures: This dimension of systemic thinking goes beyond one-way cause - effect relations.
- dynamic thinking: recognizing patterns over time (oscillations, delays), not just events.
- practical steering of systems: the right action at the right time in the right place.
From the very beginning the System Dynamics Method is closely associated with numerical computer simulation. The simulation language DYNAMO was developed in the late 50ies by a group around Jay Forrester at the MIT. DYNAMO was a key factor of the success of the system dynamics method. Modern, structural-diagram-oriented descendants of DYNAMO are:
- STELLA from High Performance Systems was the first system dynamics software which allowed graphical model input on the level of structural diagrams (stock-flow-diagrams). STELLA was first developed for APPLE Mac, later also Windows-Versions were released.
- Dynasys - is a cheap German shareware-product with a functionality similar to early STELLA versions.
- POWERSIM for Windows is a modelling tool primarely designed for the developement of management flight simulators. (Newer) POWERSIM-Models have the same data-format as STELLA.
- VENSIM Personal Learning Edition is for educational purposes free! It is a limited, yet very powerful version of a top-ranking system dynamics simulation environment.
Simple systemdynamical models can also being calculated using a simple spreadsheet program. The variables are arranged in
columns, each time-step is represented in a single row. Spreadsheet models can be very helpful for understanding the basic arithmetic of system dynamics models.
German Papers and Ressources
SD: English Papers and Ressources
See my System Dynamics Mega Link List with over 100 SD-related links!
Biosphere 2 Center
Projects about evaluation of data of our biosphere
Modeling Physical Systems.
Physics Models in STELLA (Schecker)
Road Maps
introductory course materials to system dynamics (collected by SDEP, MIT)
STELLA Models
