Adam, (01)
That's also the lesson that car makers learned: you
can't mix and match parts from a Ford, a Toyota, and
a Volkswagen. (02)
AP> ... the details of the formal definitions, and then
> all the connections to other definitions are so complex
> and intertwined it seems clear to me that the return on
> investment for merging isn't there. It's much easier
> to pick one. Trying to merge formal ontologies seems
> to me to be harder even than creating a new ontology
> from scratch. (03)
The solution that Herb Simon was trying to get across
in his "Architecture for Complexity" was to modularize. (04)
Every car major manufacturer starts with the goal of
maximizing the number of interchangeable modules among
the various models in their product line. And to a
large extent, they succeed. (05)
The same thing is true of ontologies. You don't have
to start completely from scratch, but you do have to
tailor each module with the goal of making it easy to
fit with other modules. Analyze the interdependencies,
generalize, modularize, cut the ontologies at the
"joints", and define clear interfaces. (06)
Below is Simon's parable of the two watchmakers. (07)
John
_________________________________________________________ (08)
There once were two watchmakers, named Hora and Tempus, who manufactured
very fine watches. Both of them were highly regarded, and the phones in
their workshops rang frequently -- new customers were constantly calling
them. However, Hora prospered, while Tempus became poorer and poorer and
finally lost his shop. What was the reason? (09)
The watches the men made consisted of about 1000 parts each. Tempus had
so constructed his that if he had one partially assembled and had to put
it down -- to answer the phone, say -- it immediately fell to pieces and
had to be reassembled from the elements. The better the customers liked
his watches, the more they phoned him and the more difficult it became
for him to find enough uninterrupted time to finish a watch. (010)
The watches that Hora made were no less complex than those of Tempus,
but he had designed them so that he could put together subassemblies of
about ten elements each. Ten of these subassemblies, again, could be put
together into a larger subassembly and a system of ten of the latter
constituted the whole watch. Hence, when Hora had to put down a partly
assembled watch in order to answer the phone, he lost only a small part
of his work, and he assembled his watches in only a fraction of the
man-hours it took Tempus. (011)
Herbert A. Simon, 1997, Sciences of the Artificial, 3rd Ed.,
MIT Press, Cambridge, Mass., pp. 188ff. (012)
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