- From: Mark Harrison <mark.harrison@cantab.net>
- Date: Thu, 7 May 2015 10:10:31 +0100
- To: Bernard Vatant <bernard.vatant@mondeca.com>
- Cc: W3C Web Schemas Task Force <public-vocabs@w3.org>
Dear Bernard, Just to respond to your example, that is probably an acceptable approach provided that both resources sharing that string code do so via a well-defined property that has an inverse-functional relationship (i.e. only one Subject is allowed to have that Value), much like a social security number. In that case, it's reasonable to infer that the two resources are the same. However, there are several 5-character codes in circulation, whether CAGE / NCAGE codes, US 5-digit zip codes or INSEE codes - so it's essential to unambiguously specify explicitly what the code represents - and whether the relationship is inverse functional. If that is not specified in a machine-interpretable manner, we all lose efficiency because each responsible developer must verify that relationship manually before making that assumption. The major downside of bare code strings vs URIs is that it's not immediately obvious where to go to find information - you can't simply make a web request and reasonably hope to find a definition or other relationships. Of course, as Martin points out, we need a stable foundation, which for Linked Data means stable URIs and a commitment to maintain resources and web vocabularies for the common good, within a framework that does not allow them to collapse or wither if one committed individual leaves or is run over by a bus. Best wishes, - Mark On 7 May 2015, at 09:36, Bernard Vatant <bernard.vatant@mondeca.com> wrote: > Dear all > > This issue has been surfacing again and again lately, and I would like to support Martin. I've already pushed this viewpoint here and there, I understand the reaction of "orthodox" linked data supporters for whom "things must be identified by URIs", period. But to put in bluntly, in many cases, well-maintained codes for standardized identities (languages, countries, towns, units ...) are more sustainable ways to share identities than URIs, for the obvious reasons given by Martin (URIs are volatile) plus three other ones at least. > > - Codes are not tied to any technical architecture, they can be used and exchanged across any information system, not only the Web (semantic or not). They allow to "weave beyond the Web" [1] any kind of data using them. > > - Codes have minimal semantics (if any), they just carry shared identities, and that's great. Different data publishers can propose different representations, identified by different URIs, and sharing the same standard code. The sharing of a code via a common property/value pair is the best way to provide loose coupling between those entities without engaging into the neverending ontological and technical debate of knowing if those representations represent the same/similar/equivalent thing(s), and catastrophic chaining triggered by such hazardous equivalences. > > Let me take just one example. Is not it safer to tie http://id.insee.fr/geo/commune/21231 to http://dbpedia.org/resource/Dijon by the common value of INSEE code "21231" (standardized by INSEE) than to rely on cascading sameAs leading to the stupid semantic black hole at > http://sameas.org/html?uri=http%3A%2F%2Fdbpedia.org%2Fresource%2FDijon which is the patent proof of the failure of a dogmatic and positivist use of URIs. > > [1] http://bvatant.blogspot.fr/2015/04/weaving-beyond-web.html > > > 2015-05-07 0:31 GMT+02:00 martin.hepp@ebusiness-unibw.org <martin.hepp@ebusiness-unibw.org>: > The problem is not the one time generation. The problems are as follows: > > 1. Copyright - Are you allowed to republish the code set as RDF? > 2. Sustainability - Are you commited to keep the URIs dereferencable, or will some domain grabber take the domain name once the creator has completed his/her PhD and lost interest. > 3. Updates - Will you keep the RDF version in sync whenever the standard changes? > > Unless there is a clear "yes" to all three questions, it is better to use the official codes than derived URIs. > > Martin > > > > > On 06 May 2015, at 23:56, Wes Turner <wes.turner@gmail.com> wrote: > > > > How much time do you think it would take to generate RDF (and namespaced URIs) from the linked spreadsheet? > > > > Mappings to/from UN/CEFACT codes (as owl:sameAs mappings to strings) could certainly be useful. > > > > On May 6, 2015 4:31 PM, "martin.hepp@ebusiness-unibw.org" <martin.hepp@ebusiness-unibw.org> wrote: > > I think a validator should simply use the list of valid codes from the most recent UN/CEFACT document (available as MS Excel from http://www.unece.org/cefact/codesfortrade/codes_index.html). > > > > There might be unit of measurement ontologies out there that hold the UN/CEFACT Common Code string for a subset of all units as a literal value. But for validation, one should use the authoritative list from the Excel files (since they are updated from time to time). > > > > URIs are not better than strings for validation, because URIs are strings. > > > > Best wishes / Mit freundlichen Grüßen > > > > Martin Hepp > > > > ------------------------------------------------------- > > martin hepp > > e-business & web science research group > > universitaet der bundeswehr muenchen > > > > e-mail: martin.hepp@unibw.de > > phone: +49-(0)89-6004-4217 > > fax: +49-(0)89-6004-4620 > > www: http://www.unibw.de/ebusiness/ (group) > > http://www.heppnetz.de/ (personal) > > skype: mfhepp > > twitter: mfhepp > > > > Check out GoodRelations for E-Commerce on the Web of Linked Data! > > ================================================================= > > * Project Main Page: http://purl.org/goodrelations/ > > > > > > > > > > > On 06 May 2015, at 20:34, Wes Turner <wes.turner@gmail.com> wrote: > > > > > > Thanks! > > > > > > I notice that with QUDT there are SI conversion factors and complete URIs for each unit. > > > > > > Is there a schema for validation of "schema:QuantativeValues supports all UN/CEFACT Common Codes"? > > > > > > (A similar quandry as with MedicalCode; where URI namespaces (like icd10:) would be more helpful for terminological validation and disambiguation than plain string keys) > > > > > > On May 6, 2015 4:26 AM, "martin.hepp@ebusiness-unibw.org" <martin.hepp@ebusiness-unibw.org> wrote: > > > > > > > > Hi Wes, > > > > sorry for a very late reply: > > > > > > > > Actually you could easily use schema:QuantitativeValue for both time and volume, with SEC as the unit code for t and LTR as the unit code for liters, and link both via schema:valueReference, or better, and owl:subProperty thereof. > > > > > > > > For the principle, see > > > > > > > > http://wiki.goodrelations-vocabulary.org/Documentation/Structured_values_and_value_references > > > > > > > > > > > > schema:QuantativeValues supports all UN/CEFACT Common Codes for units, which should cover all you need: > > > > > > > > > > > > http://wiki.goodrelations-vocabulary.org/Documentation/UN/CEFACT_Common_Codes > > > > > > > > (Mind the full list in the public Excel files, the page just highlights a small subset.) > > > > > > > > Best wishes / Mit freundlichen Grüßen > > > > > > > > Martin Hepp > > > > > > > > ------------------------------------------------------- > > > > martin hepp > > > > e-business & web science research group > > > > universitaet der bundeswehr muenchen > > > > > > > > e-mail: martin.hepp@unibw.de > > > > phone: +49-(0)89-6004-4217 > > > > fax: +49-(0)89-6004-4620 > > > > www: http://www.unibw.de/ebusiness/ (group) > > > > http://www.heppnetz.de/ (personal) > > > > skype: mfhepp > > > > twitter: mfhepp > > > > > > > > Check out GoodRelations for E-Commerce on the Web of Linked Data! > > > > ================================================================= > > > > * Project Main Page: http://purl.org/goodrelations/ > > > > > > > > > > > > > > > > > > > > > On 01 May 2015, at 13:45, ☮ elf Pavlik ☮ <perpetual-tripper@wwelves.org> wrote: > > > > > > > > > > Hi Wes, > > > > > > > > > > On 01/26/2014 07:20 AM, Wes Turner wrote: > > > > >> Say I am trying to share a tabular dataset. [1] There's metadata for > > > > >> the Dataset, and there's metadata for the particular columns (which > > > > >> applies to the particular data items). > > > > >> > > > > >> For example: > > > > >> > > > > >> t volume (liters) > > > > >> ----------------- > > > > >> 1 1 > > > > >> 2 0.7 > > > > >> 3 0.5 > > > > >> 4 0.3 > > > > >> 5 0.1 > > > > >> > > > > >> Questions > > > > >> =========== > > > > >> # Is there (a good) way to specify these units and quantities (in > > > > >> addition to XSD datatypes)? > > > > > You might like to check out > > > > > * https://iotdb.org/pub/iot-unit.html > > > > > > > > > > Cheers! > > > > > > > > > > > > > > > > > > > > > > -- > Bernard Vatant > Vocabularies & Data Engineering > Tel : + 33 (0)9 71 48 84 59 > Skype : bernard.vatant > http://google.com/+BernardVatant > -------------------------------------------------------- > Mondeca > 35 boulevard de Strasbourg 75010 Paris > www.mondeca.com > Follow us on Twitter : @mondecanews > ----------------------------------------------------------
Received on Thursday, 7 May 2015 09:11:01 UTC