New Release (1.1) of Molecules
Posted: Fri Sep 13, 1996 4:46 pm
A new version (1.1) of the molecules is available for free download
(http://www.std.com/vensim/molecules.html). This version
contains additional structures and some reworked connections between molecules.
Also new is an 80-page document describing each molecule.
Again, we hope you find the molecules useful. As usual, please send any
comments or additional molecules to me at:
JimHines@Interserv.Com
This version is still to be considered an "Alpha" stage. Molecules are language
neutral. But, the current software version still only works with Vensim. Our
intention remains that when the software is officially released, it will work
with all major system dynamics platforms. (The 80-page description is a
stand-alone document).
For those who may have missed the discussions on molecules, a brief description
follows.
DESCRIPTION: Molecules are building-blocks for SD models. They are small
stock-and-flow structures that are solutions to little modeling problems.
Molecules have always been with our field: Smooths and delays qualify. In
addition there are structures for representing prices, productivity, etc.
Very experienced modelers carry in their heads a warehouse of molecules. We
are trying to make these moelcules explicit, easy to discuss, easy to
refine, and easy to access for experienced and inexperienced modelers alike.
Molecules are not to be confused with Archetypes or Generic Structures.
Archetypes are complete dynamic lessons, really best captured as loops or in
words. Archetypes represent system dynamics wisdom. In contrast, molecules
represent modeling wisdom and are best represented as stock and flow diagrams or
equations. Finally, "Generic Structures" is a blanket term referring to
recurring or valuable structures -- both stock and flow and causal loop. The
term "Generic Structures" covers archetypes, molecules, and even certain classic
models such as Jay Forresters Market Growth as Influenced By Capital
Investment.
Regards,
Jim Hines
LeapTec and MIT
(http://www.std.com/vensim/molecules.html). This version
contains additional structures and some reworked connections between molecules.
Also new is an 80-page document describing each molecule.
Again, we hope you find the molecules useful. As usual, please send any
comments or additional molecules to me at:
JimHines@Interserv.Com
This version is still to be considered an "Alpha" stage. Molecules are language
neutral. But, the current software version still only works with Vensim. Our
intention remains that when the software is officially released, it will work
with all major system dynamics platforms. (The 80-page description is a
stand-alone document).
For those who may have missed the discussions on molecules, a brief description
follows.
DESCRIPTION: Molecules are building-blocks for SD models. They are small
stock-and-flow structures that are solutions to little modeling problems.
Molecules have always been with our field: Smooths and delays qualify. In
addition there are structures for representing prices, productivity, etc.
Very experienced modelers carry in their heads a warehouse of molecules. We
are trying to make these moelcules explicit, easy to discuss, easy to
refine, and easy to access for experienced and inexperienced modelers alike.
Molecules are not to be confused with Archetypes or Generic Structures.
Archetypes are complete dynamic lessons, really best captured as loops or in
words. Archetypes represent system dynamics wisdom. In contrast, molecules
represent modeling wisdom and are best represented as stock and flow diagrams or
equations. Finally, "Generic Structures" is a blanket term referring to
recurring or valuable structures -- both stock and flow and causal loop. The
term "Generic Structures" covers archetypes, molecules, and even certain classic
models such as Jay Forresters Market Growth as Influenced By Capital
Investment.
Regards,
Jim Hines
LeapTec and MIT