Posted by ""Alan Graham"" <
Alan.Graham@paconsulting.com>
Hi Ali,
There are many models of physiological and metabolic systems, a few explicitly by System Dynamicists, and many many more that are dynamic models differing mostly in nomenclature from ""standard SD"".
System Dynamics modeling of medical systems started in the 1970s with Richard O. Foster's MIT thesis on glucose regulation and diabetes, and my MIT thesis on endocrine regulation of the onset of puberty. Both of these are available online through MIT. Erik Mosekilde has done continuing work on dynamics of nephrons in the kidneys, at least one publication appearing in the System Dynamics Review. PA Consulting did an extensive model of immune response, capable of recreating viral and bacterial attack, and onset and treatment of rheumatoid arthritis. (Due to commercial circumstances, this work was never published.) Jack Homer did an excellent ISDC conference paper on drug resistance adaptation in bacteria. Doubtless I'm not recalling or missing several.
Beyond these, a significant portion of metabolic and physiological models in the medical literature are based on rather simplified (by SD
standards) differential equations. Given that such models aren't using the SD skills in understanding decision-making, it's difficult to say that they're definitely not SD models. (Editorial: Of course, many such models are academic, and have the only apparent usefulness or purpose of getting published, but truth be told, we in SD, at least in the publications side, aren't entirely free of that particular lacuna.)
Beyond these, there's a loosely-organized movement called The Physiome Project, whose aim is to model the entire body, in the same way that the Genome Project mapped the entire human genome. Google it.
Beyond these, there's a newer movement called Systems Biology, whose goal is more comprehensive examination of most traditional topics. And guess what, many of the models are remarkably System Dynamics like.
Bottom line is, there's a lot done and being done with philosophy, aims and tools very much like SD, and a small fraction of that is ""SD-branded"".
Cheers,
Alan
Alan K. Graham, PhD
Federal and Defense Services
PA Consulting Group
Posted by ""Alan Graham"" <
Alan.Graham@paconsulting.com> posting date Tue, 16 Jan 2007 12:50:44 -0500 _______________________________________________