Re: Temporal validity: alternative for dcterms:valid?

Oops, please ignore my previous message. It was intended for
public-lod@w3.org. I made an addressing mistake.

Frans

2015-12-24 16:55 GMT+01:00 Frans Knibbe <frans.knibbe@geodan.nl>:

> Hello again,
>
> The DCMI Metadata Terms vocabulary
> <http://dublincore.org/documents/2012/06/14/dcmi-terms/> seems to have
> all the basic ingredients for building a versioning mechanism in to a
> dataset (which is or should be a very common requirement). Objects in a
> dataset can have life spans (temporal validity), be versions (
> dcterms:hasVersion
> <http://dublincore.org/documents/2012/06/14/dcmi-terms/#terms-hasVersion>/
> dcterms:isVersionOf
> <http://dublincore.org/documents/2012/06/14/dcmi-terms/#terms-isVersionOf>)
> of another resource and replace each other (dcterms:replaces
> <http://dublincore.org/documents/2012/06/14/dcmi-terms/#terms-replaces>/
> dcterms:isReplacedBy
> <http://dublincore.org/documents/2012/06/14/dcmi-terms/#terms-isReplacedBy>
> ).
>
> But as Jeni Tennison has noted some time ago
> <http://www.jenitennison.com/2010/02/27/versioning-uk-government-linked-data.html> (see
> final section 'Unanswered Questions'), a versioning scheme based on DCMI
> has a weak spot: the property for denoting temporal validity (
> dcterms:valid
> <http://dublincore.org/documents/2012/06/14/dcmi-terms/#terms-valid>) is
> impractical to the point of being unusable. Dcterms:valid only takes
> literals (rdfs:Literal) as value, which makes it hard to use it for
> practical expressions of time intervals. Time intervals should be compound
> objects that are based on useful datatypes. For instance, xsd:dateTime (for
> dates) or xsd:integer (for years or seconds (e.g. in UNIX time)) could be
> used in SPARQL queries to filter or order temporal data. In a versioned
> dataset queries like 'give me all changes between time T1 and time T2' or
> 'give me the state of the dataset at time T3' should be easy to create and
> to resolve. It seems to me that this requires proper and well supported
> data types. A text string notation for time intervals is recommended by
> DCMI: dcmi-period <http://dublincore.org/documents/dcmi-period/>. It is
> easy and versatile enough, but the average triple store probably does not
> recognize this notation as temporal or numerical data. So I wonder if there
> is a good alternative for dcterms:valid somewhere that can be used to
> indicate temporal validity.
>
> I did find http://www.w3.org/ns/prov#invalidatedAtTime in PROV-O, which
> could be considered applicable, but a matching property to indicate the
> start of the time period of validity does not seem to exist in PROV-O.
> Also, its range is xsd:dateTime, which I think is too restrictive because
> the time needs to be known up to the level of seconds.
>
> Does this gap still need to be plugged? Or is the solution out there?
>
> Greetings,
>
> Frans
>
>
>
>