- From: Pat Hayes <phayes@ihmc.us>
- Date: Mon, 18 Jan 2010 11:00:39 -0600
- To: Harry Halpin <hhalpin@ibiblio.org>
- Cc: Kjetil Kjernsmo <kjetil@kjernsmo.net>, semantic-web@w3.org
On Jan 18, 2010, at 8:18 AM, Harry Halpin wrote: > Re adoption, basically I can't really point most hackers or > implementers at the RDF specs without terrifying them (yes, syntax > matters). A lot of them get overwhelmed - so when explaining RDF for > the first time, to be honest I tend to point them at TimBL's N3 > tutorial [1] and *then* the specs. > > A simplification of the current specs is needed, with the things > everyone uses (i.e. named graphs) added into the spec, with things > like bags and list dropped. I also would like to have a decent way to > express ordered lists in RDF and a clearly blessed (i.e. Turtle) > syntax, along with JSON and Atom serializations. I think this is > important for the future of RDF - new apps are great, but we need more > programmers, and giving the specs a spring-cleaning would help. Well, you need tutorials/ introductions/ RDF-for-Dummies stuff. That is being written, but it s not what should be in a spec, right? Pat > > On Thu, Jan 14, 2010 at 9:43 PM, Kjetil Kjernsmo > <kjetil@kjernsmo.net> wrote: >> All, >> >> Like some others, I think the adoption problem is not solved by >> another >> spec, but by actually writing useful stuff. Still, I think there >> are things >> that should be fixed, but relatively minor things. I'm +1 on stuff >> like >> graph naming, kill bag, rec on serialisations, etc, but let me also >> bring >> forward one little thing that is of major importance: Units. >> > > +1. This is a major problem - one that also haunts XML Schema > Data-types. Jen Tennison has some excellent work in this area [1]. > Perhaps extensible data-typing is what is needed? > > [1] http://www.w3.org/2000/10/swap/Primer.html > [2] http://www.jenitennison.com/datatypes/ > >> There are no good ways to express the units of numbers in RDF. Yet, >> most >> numbers out there are expressed with units. You could do it with >> datatype >> URIs, but datatypes are orthogonal to units. You could do it with >> some >> hacks, people have been doing that, but it quickly gets complicated >> and far >> from ideal. We really need a simple way to express units, and ways >> to make >> it possible for agents to convert numbers between different units. >> >> Concrete example: Lets use DBPedia to find aircrafts with a certain >> maximum >> take-off-weight that can take off from airfields with a certain >> maximum >> runway length. All the data is on Wikipedia, and writing the SPARQL >> query >> should be easy (actually doing it is left as an exercise to the >> reader ;-) >> ). >> >> But it can't be done, at least not without a lot of painful hacking >> on the >> client side, partly because not all the data is in DBPedia >> (notably, the >> take-off-run when the aircraft is fully loaded i.e. at MTOW), but >> importantly because of the units used, see e.g.: >> http://dbpedia.org/page/Stockholm-Arlanda_Airport >> where the numbers are dimensionless, and the unit is in the >> property, e.g.: >> dbpprop:r1LengthF, while the MTOW is expressed like this: >> dbpprop:maxTakeoffWeightMain "20,200 lb"@en ; >> for http://dbpedia.org/page/Cessna_Citation_Excel >> >> So, this is actually pretty useless. You cannot do the stuff that >> Linked >> Data should be good at with this. >> >> So, you could say that this could be done Right and Consistently, >> whatever >> Right may be, but when we, as a community (DBPedia is our community >> project, right) has failed to do it Right, I would blame it on that >> it is >> too hard to do Right. >> >> Not only is this important for everyday applications, it is also >> indispensable for most scientific applications. So, that's my main >> requirement. >> >> Cheers, >> >> Kjetil >> -- >> Kjetil Kjernsmo >> kjetil@kjernsmo.net >> http://www.kjetil.kjernsmo.net/ >> >> > > ------------------------------------------------------------ IHMC (850)434 8903 or (650)494 3973 40 South Alcaniz St. (850)202 4416 office Pensacola (850)202 4440 fax FL 32502 (850)291 0667 mobile phayesAT-SIGNihmc.us http://www.ihmc.us/users/phayes
Received on Monday, 18 January 2010 17:01:42 UTC