Re: URIs / Ontology for Physical Units and Quantities

Dear Martin,

I understand your very valid concerns about Linked Data resources that are not supported and maintained and end us wasting time for developers.  However, from this thread it also seems that there is quite some interest in having a well recognised ontology for units of measure in which units have corresponding stable URIs that link to definitions, UN ECE codes, conversion factors and offsets, etc.  QUDT 1.1 made a very good start on this, although it had one or two inaccurate cross-references.  For example, I found within http://qudt.org/vocab/unit#Grain the following nonsensical triple:

 <http://qudt.org/vocab/unit#Grain>  skos:exactMatch  <http://dbpedia.org/resource/Cereal> .

There are some other gaps in QUDT 1.1, such as missing resources for units such as milligram, microgram - and because the SI base unit of mass is the kilogram, it is not sufficient to simply define the multipliers such as 'milli', 'micro', because we don't usually talk about milligrams as microkilograms, for example.

Having said that, if QUDT 1.1 were updated, corrected, supported a more complete set of units and provided cross-references to the corresponding UN ECE Common Code values as strings, I think it (or something very like it) could be an extremely valuable resource for everyone, especially because of the conversion factors and offsets.

The QUDT.org website appears to be last updated in March 2014 and there is some information and a presentation by Ralph Hodgson (copied) about the plans for release 2.0 of QUDT.  However, I'm not sure whether that work has stalled or is under-resourced or is spending a long time in careful internal review.  Maybe those of us who are interested in making this happen could offer to share the workload and accelerate the progress.  In case NASA / TopQuadrant is no longer the place to host it, then perhaps we could reasonably ask W3C to host it in perpetuity and maintain a liaison with the UN, ISO and other relevant bodies to ensure that we're aware of their changes that should be reflected through maintenance updates to such a vocabulary.

We're soon hoping to see much more structured data about products being published openly on the web as linked data, potentially including details about ingredients, nutrition and allergens.  GS1 has already prepared begun drafting a web vocabulary [ see http://www.gs1.org/gtin_plus_public_review ] to help manufacturers and retailers express such information in much richer detail than they can currently using schema.org alone - and efforts are underway to harmonise this effort with schema.org to make life easier for developers.  I expect that a stable supported ontology with URIs and Linked Data for units of measure along the lines of a QUDT 2.0 could be far more useful to software developers than simply denoting a unit of measure by its UN ECE Common Code string.  We can certainly do better than that.  It could almost certainly avoid a large amount of duplicated effort in coding conversion factors and offsets and would also help to ensure that whether the product specifications are provided in SI units or non-SI units (as they are in different regions of the world), the same quantitative information is readily available so software applications, without ambiguity or unnecessary duplication of effort by developers.

I hope that Ralph Hodgson can chime in with a brief status update on QUDT 2.0 - and also that those of us who would be interested in helping to accelerate this (or something similar) can step forward and offer to help with reviewing it or beta testing it - or filling in the gaps for the missing features.

Best wishes,

- Mark Harrison




On 7 May 2015, at 09:08, martin.hepp@ebusiness-unibw.org wrote:

> Dear Kingsley:
> Technically, as we agree, this is no big deal. 
> 
> But there are so many abandoned RDF / Semantic Web efforts rottening on the Web and wasting the time of developers who try to built something on top of it -- until they find out that the project is way out of date -- that I do not see any gain in such a quick fix.
> 
> Martin
> 
> 
>> On 07 May 2015, at 01:25, Kingsley Idehen <kidehen@openlinksw.com> wrote:
>> 
>> On 5/6/15 6:31 PM, martin.hepp@ebusiness-unibw.org wrote:
>>> 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
>> 
>> Martin,
>> 
>> What's wrong with:
>> 
>> <#someResolvableVariantOfIdentifier>
>> a owl:Thing ;
>> dcterms:identifier "{literal-variant-of-standard-identifier}" .
>> 
>> Which can be further embellished by Linked Data publisher in their ontology/vocabulary by adding the following:
>> 
>> dcterms:identifier
>> a owl:InverseFunctionalProperty .
>> 
>> Productive workflow:
>> 
>> 1. Get the data dump in a spreadsheet
>> 2. Save as CSV
>> 3. Load into LOD or Google Refine
>> 4. Map to relevant ontology (existing, or new)
>> 5. Dump data into an RDF document
>> 6. Publish (note: using # as indexical mechanism makes the publication Linked Open Data prinicples compliant off-the bat).
>> 
>> 
>> It can be done quite easily. I deliberatly opted not to do it :)
>> 
>> 
>> Kingsley
>>> 
>>> 
>>> 
>>>> 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!
>>>>>>> 
>>>>>>> 
>>> 
>>> 
>> 
>> 
>> -- 
>> Regards,
>> 
>> Kingsley Idehen 
>> Founder & CEO
>> OpenLink Software
>> Company Web: http://www.openlinksw.com
>> Personal Weblog 1: http://kidehen.blogspot.com
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>> 
>> 
> 
>

Received on Thursday, 7 May 2015 08:57:21 UTC