1. systems archetypes

a system dynamics structure that is common to many systems.

2. systems thinking

thought process that involves 1) seeing interrelationships (feedback loops) instead of linear cause-effect chains and 2) seeking processes of change over time rather than snapshots. Systems thinking involves understanding many concepts of system dynamics, most notably, feedback. it helps thinkers see things on three levels: events, patterns of behavior, and system structure

3. table function

feature used to formulate a non-linear relationship when it is necessary to use an auxiliary variable that is not simple algebraic function of other variables. the function is a graph that can be sketched to capture the relationship at hand. a table function can be represented with a graphical function diagram

4. tragedy of common

the structure in which each person pursues action beneficial only to oneself, then eventually the system cannot support all the activity and everyone experiences diminishing results. the commons is the resources everyone calls upon, but does not take care to replenish. it is a systems archetype that surfaces in many socioeconomic systems. the Fish Banks Game is an excellent example of a tragedy of commons behavior

5. transient

a dynamic response that does not persist

6. unit-conversion

a modeling function that allows for units of a certain variable to change as that variable is altered. example: cloth (square meters) is made into clothing (articles)

7. validity

judgment of a model's suitability for a particular purpose. a model is valid when it accomplishes what is expected of it

8. VENSIM

modeling software for system dynamics. It offers a "workbench" featuring simulation tools for tracing sources of behavior in a model

9. vicious cycle

reinforcing, amplifying process that yields undesirable results

10. virtuous cycle

process that reinforces in desired directions