IAU thesaurus in RDF (an update)

Wed Oct 10 02:55:59 PDT 2007

The issue of using singular or plural terms is not a trivial one and one which we should consider carefully. The major issue to consider is what are the terms in the vocabulary going to be used for? If they are merely going to be used for tagging an object then singular is fine. However, if they are going to be used for searching for objects then plural terms should be used as this is the mind set of a searcher.

Section 7.2 of L Willpower, Thesaurus principles and practice http://willpowerinfo.co.uk/thesprin.htm#7.2:Singular is worth a read on this subject. Also note that the British Standard for thesaurus construction recommends that plural terms should be used.

Cheers,

Alasdair

Alasdair J G Gray <http://www.dcs.gla.ac.uk/~agray/> 

Research Associate: Explicator Project

Computer Science, University of Glasgow

0141 330 6292

From: owner-semantics at eso.org [mailto:owner-semantics at eso.org] On Behalf Of Frederic V. Hessman
Sent: 8 October 2007 15:42
To: Ed Shaya
Cc: IVOA semantics
Subject: Re: IAU thesaurus in RDF (an update)

	            I suggest that the vocabulary contains only singular terms.  Right now it is inconsistent on this.  All of the star things are _stars, but many terms are singular like abundance, Alven_surface, age.

	Perhaps there was some initial idea of having singular subject headings

	and plural object classes, but this gets very muddy fast.  I don't see any real benefit in plural over singular, it is just an extra character or two.

This is what we used in the SV proposal, thinking that singular was simpler.   I don't know what Shobbrook^2 were thinking about: maybe plural was intended to indicate some sense of generality.  Their usage suggests that abstract concepts were kept singular (e.g. "convections" doesn't make any sense) but things which are instantiable were made plural (e.g. "convective flows").  It wouldn't be too hard to convert everything to singular, but....

#Stars only has bright_stars and Sun as narrower.  There should be much

more.

Wasn't me!

"#Kelvin related temperature_scale", but it is a temperature_scale.

More exactly, it is an absolute_temperature_scale which is a

temperature_scale.

Hey, there is no Fahrenheit at all.  Was this an intentional slight?

You're right.  We also forgot furlongs, stones, bushels, fluid ounces, pecks, miles, nautical miles, knots, ....

"#terrestrial_radiation narrower atmospheric_radiation", but one now

sees atmospheric radiation on Jupiter etc, so I would say the relation

is reversed.

"#turbulence_Earth_atmosphere narrower microturbulence" and

"#turbulence_Earth_atmosphere narrower macroturbulence".

Not really.

"emission_line_star narrower shell_star".

Not really.  Shell stars have absorption lines from a shell of gas.

They could have emission lines as well, but that is not in the definition.

I'm only responsible for a zillionth of the BT's, NT's, and RT's, so don't blame me for most of this.

I'm frankly not very interested in the ontological info just yet (I'm still trying to check for the right tokens), but I'll be happy to correct any concrete example submitted by anyone as long as you indicate 1) the present entry; and 2) proposed corrected entry, and not just one BT/NT/RT at a time!

Too bad we can't get the list onto a good Wiki site..... (hint, hint, hint): I'm happy to do more than my share of editorial work, but if ya'll start to mess with the ontological info, the job will get gigantic.  The present goal should be to remove egregious errors only.

Someone asked if there needs to be Individuals.  This already has Sun,

Moon, Earth, Mars and others.  It turns out that there are a few that are needed because other terms are so related to them.  Although one

probably could substitute #spicules skos:related #stars for #spicules

skos:related #Sun, etc.  But, maybe we should have both.  But it is clear that one should have at least a few Individuals.

Absolutely.  The original IAU thesaurus just had the Sun and the Milky Way, not even the Solar System planets.  For lack of time, I only went as far as Pluto & Ceres, Moon, and Solar System.

Talking about individuals.  There is a #velocity_of_light.  Do we need

velocity_of_light_in_vacuum to distinguish from in_medium?

Good question.   My gut response is no, thinking that the speed will be appropriately derivable from the situation, but I might be wrong.  Do we then need "frequency_in_a_medium"?  Ugh!

infrared_radiation should have broader electromagnetic_radiation, as

ultraviolet_radiation has.  

Indeed.  In fact, although I have been through the SV tokens on the search for missing things, someone should go through the UCD list and do the same:  the final official IAU list should at least be able to cover the UCD concepts.

Is infrared_radiation synonymous with infrared_emission?  

A good example of how Shobbrook^2 put in more casual terms which librarians might encounter in astronomical texts but without any formal physical need.  On the other hand, "infrared_emission" implies not only "infrared_radiation" but also some source, and we don't yet have a standardized means of combining tokens.   In any case, for pure reasons of compatibility,  we should keep the original IAU list at least in the form of ALT's if they make any sense whatever.

I don't see a way for SKOS to say SameAs.  How does one say iau:stars sameas cds:stars?

A question for the pundits, not me :-)

Rick

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