[seek-kr] ontology figure from abq

[Matt Jones]

Bertram,

Yes, dimensional analysis is the correct term for the manipulation of 
unit types from STMML.  Its all simple algebra, and is generally taught 
early on (I think I first learned it in high school in chemistry). I 
don't understand how you plan on 'extending' what Shawn did because what 
he did is already dimensional analysis.  What am I missing here?

One important area that we have only superficialy considered is the area 
of 'dimensionless' numbers.  I think this exposes a lot of the 
distinction between 'UnitType' and 'SemanticType', but its pretty muddy 
for me.  The problem boils down to this:  dimensionless numbers are 
often ratios of two quantities that are measured in the same units.  For 
example, grams of Carbon per grams of Nitrogen (the C/N ratio) is 
dimensionless because the unit grams cancel.  However, there is 
important information that still needs to be captured (e.g., that we are 
measuring Carbon and Nitrogen, not Carbon and Oxygen).  This part, the 
'what' that is being measured, is somehow part of the semantic type -- I 
think it fits nicely into the diagram I posted to CVS yesterday.  The 
problem really crops up when considering 'counts' of things, which is 
incredibly common in ecology.  I wrote a bit of a treatise on this topic 
with respect to its impact on EML [1], and several people followed up 
with some excellent commentary [2] [3] [4].  In [4] Tim Bergsma presents 
some interesting ideas about just what a "dimension" is and how it 
relates to counts.  In [3] Peter McCartney follows up with ideas about 
what might be in a semantic type in EML.  You might find those to be 
interesting reading, as I stated that SEEK would be dealing with these 
issues head on in that email ;-)

Matt

[1]http://www.ecoinformatics.org/pipermail/eml-dev/2003-March/000738.html
[2]http://www.ecoinformatics.org/pipermail/eml-dev/2003-March/000744.html
[3]http://www.ecoinformatics.org/pipermail/eml-dev/2003-March/000745.html
[4]http://www.ecoinformatics.org/pipermail/eml-dev/2003-March/000747.html

Bertram Ludaescher wrote:
> 
> Hi Matt:
> 
> Thanks! 
> 
> Shawn and I had discussed units, unit types, quantities, dimensions
> and the likes today.
> 
> I found some interesting papers on "dimensional analysis" and was
> wondering whether that could be a natural extension to the simple
> "reasoning with units" that Shawn has implemented in Prolog.
> 
> I found this simple intro quite readable:
> 	http://www.physics.uoguelph.ca/tutorials/dimanaly/index.html
> 
> The next level seems this:
> 	http://www.wikipedia.org/wiki/Dimensional_analysis
> 
> which also has a pointer to Buckingham's \pi-theorem
> 
> This guy seems to be really ino dim.-analysis:
> 	http://www.isd.uni-stuttgart.de/~rudolph/
> 
> Also: this book includes a chapter on applying dimensional analysis to 
> ecology:
> 	http://www.amazon.com/exec/obidos/tg/detail/-/0444892508/104-2454972-2037526?v=glance
> 
> What do the Eco-folks say? Is this worth investigating further for
> adding not only unit conversion but more general reasoning and in
> particular dimensional analysis to SMS?
> 
> Bertram
> 
> 
> 
> 
>>>>>>"MJ" == Matt Jones <jones at nceas.ucsb.edu> writes:
> 
> MJ> 
> MJ> Mark, Bertram, Shawn, and Rich,
> MJ> I checked in the diagram that we made in ABQ regarding the carbon flow 
> MJ> ontology.  It is in CVS:
> MJ>    seek/docs/figures/seek-cf-measure-ontology.ai
> MJ> and in case you don't have Adobe Illustrator:
> MJ>    seek/docs/figures/seek-cf-measure-ontology.png
> MJ> 
> MJ> 
> MJ> The major change is the addition of "UnitType" to the properties of 
> MJ> MeasurementType.  I was thinking where "unit" went (as opposed to 
> MJ> UnitType) and decided it was a property of a particular attribute rather 
> MJ> than a MeasurementType.
> MJ> 
> MJ> This whole thing doesn't really consider nominal and ordinal scale 
> MJ> things, so we need to determine how MeasurementScale fits in to the 
> MJ> picture.  But I thought my updated version would be of use to you.
> MJ> 
> MJ> 
> MJ> Matt
> MJ> 
> MJ> -- 
> MJ> -------------------------------------------------------------------
> MJ> Matt Jones                                     jones at nceas.ucsb.edu
> MJ> http://www.nceas.ucsb.edu/    Fax: 425-920-2439    Ph: 907-789-0496
> MJ> National Center for Ecological Analysis and Synthesis (NCEAS)
> MJ> University of California Santa Barbara
> MJ> Interested in ecological informatics? http://www.ecoinformatics.org
> MJ> -------------------------------------------------------------------
> MJ> 
> MJ> _______________________________________________
> MJ> seek-kr mailing list
> MJ> seek-kr at ecoinformatics.org
> MJ> http://www.ecoinformatics.org/mailman/listinfo/seek-kr

-- 
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Matt Jones                                     jones at nceas.ucsb.edu
http://www.nceas.ucsb.edu/    Fax: 425-920-2439    Ph: 907-789-0496
National Center for Ecological Analysis and Synthesis (NCEAS)
University of California Santa Barbara
Interested in ecological informatics? http://www.ecoinformatics.org
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