Re: License unknown

I concur. This is clear from the semantics of OWL. Understand the
difference between integrity constraints and OWL assertions.

If you want to say that there was an attempt to find a license and that it
couldn't be found, say that. You could do so as an annotation on the axiom,
or as a distinct property e.g.
:tried-to-determine-license "true"^xsd:Boolean

This can remain true, as a historical fact, even after a license is found.

For more about integrity constraints see http://clarkparsia.com/pellet/icv/

-Alan



On Monday, June 16, 2014, Jerven Bolleman <me@jerven.eu> wrote:

> Hi Alasdair,
>
> I think you are closing the world the wrong way. Both in limiting a
> dataset to have one license and secondly by having an "unknown" string
> to encode that you don't know something.
> Instead of using "unknown" you should use a blank node.
>
> cc:CC0 owl:sameAs "unknown"
>
> is plain wrong and can't be inferred
>
> cc:CC0 owl:sameAs _:1
>
> is fine and a nice way of allowing dataset from different sources
> descriptions to be combined and give more information.
>
> If you don't want a blank node, make a local node instead.
> cc:CC0 owl:sameAs <./#license>
>
> I implore you to change your mind on this. Choose semantics over special
> values!
>
> Regards,
> Jerven
>
>
> On Mon, Jun 16, 2014 at 5:44 PM, Gray, Alasdair J G <A.J.G.Gray@hw.ac.uk
> <javascript:;>> wrote:
> > Hi Jerven,
> >
> > We are trying to ensure that a license is provided for a dataset, and
> that
> > only one license is provided. (We are closing the world in certain
> areas.)
> >
> > Our proposed solution is written up at
> > https://github.com/joejimbo/HCLSDatasetDescriptions/issues/65
> >
> > Alasdair
> >
> > On 2 Jun 2014, at 16:47, Jerven Bolleman <me@jerven.eu <javascript:;>>
> wrote:
> >
> > Hi Alasdair,
> >
> > It is good practice in my opinion to not state unknown facts. If you
> > want to state there should be a license but you don't know it I think
> > some owl modelling is called for.
> >
> > e.g. roughly like this.
> >
> > dusty_data a dct:Dataset .
> > dusty_data rdfs:subClassOf [ a owl:Restriction ;
> >                                            owl:onProperty dct:license ;
> >                                            owl:minCardinality 1 ]
> >
> >
> > If anyone does something like
> >
> > dusty_data a dct:dataset .
> > dusty_data dct:license bad_example:unknown_license .
> >
> > and then someone figures out it has a license .
> >
> > dusty_data a dct:Dataset .
> > dusty_data dct:license cc:zero .
> >
> > And puts all those triples into one store/ontology then queries will
> > start to return wrong data.
> >
> > SELECT ?datasetWithALicense
> > WHERE {
> > ?datasetWithALicense dct:license ?license .
> > }
> >
> > Will give 2 bindings for ?dataset and ?license one of them being wrong
> now.
> >
> > If you ask the same question depending on the better modelling then
> > you get the correct answer in both cases.
> >
> > SELECT ?datasetWIthoutLicense
> > WHERE {
> > ?datasetWIthoutLicense a dct;Dataset .
> > MINUS ( ?datasetWIthoutLicense dct:license ?license )
> > }
> >
> > SELECT ?datasetWIthALicense
> > WHERE {
> > ?datasetWIthALicense a dct;Dataset .
> > ?datasetWIthALicense dct:license ?license .
> > }
> >
> > Both give the expected results.
> >
> >
> > In general in RDF just state what you know and describe what you don't
> know.
> >
> > Regards,
> > Jerven
> >
> > On Mon, Jun 2, 2014 at 5:25 PM, Gray, Alasdair J G <A.J.G.Gray@hw.ac.uk
> <javascript:;>>
> > wrote:
> >
> > Hi,
> >
> > I am working to help shape the Healthcare and Life Sciences community
> > profile for describing datasets, current version available from [1]
> >
> > One of our goals is that there is a minimal set of properties that are
> > available for all datasets, and we would like these properties to include
> > the license. However we have the problem that for several legacy datasets
> > the license is simply unknown. Does anyone know of a resource that can be
> > used to represent that the license is unknown as the value of a
> > dcterms:license predicate?
> >
> > Thanks
> >
> > Alasdair
> >
> > [1] https://github.com/joejimbo/HCLSDatasetDescriptions
> >
> > Alasdair J G Gray
> > Lecturer in Computer Science, Heriot-Watt University, UK.
> > Email: A.J.G.Gray@hw.ac.uk <javascript:;>
> > Web: MailScanner has detected a possible fraud attempt from
> > "www.macs.hw.ac.uk" claiming to be http://www.alasdairjggray.co.uk
> > ORCID: http://orcid.org/0000-0002-5711-4872
> > Telephone: +44 131 451 3429
> > Twitter: @gray_alasdair
> >
> >
> >
> >
> >
> >
> > ________________________________
> >
> > Sunday Times Scottish University of the Year 2011-2013
> > Top in the UK for student experience
> > Fourth university in the UK and top in Scotland (National Student Survey
> > 2012)
> >
> > We invite research leaders and ambitious early career researchers to
> join us
> > in leading and driving research in key inter-disciplinary themes. Please
> see
> > www.hw.ac.uk/researchleaders for further information and how to apply.
> >
> > Heriot-Watt University is a Scottish charity registered under charity
> number
> > SC000278.
> >
> >
> >
> >
> > --
> > Jerven Bolleman
> > me@jerven.eu <javascript:;>
> >
> >
> > Alasdair J G Gray
> > Lecturer in Computer Science, Heriot-Watt University, UK.
> > Email: A.J.G.Gray@hw.ac.uk <javascript:;>
> > Web: MailScanner has detected a possible fraud attempt from
> > "www.macs.hw.ac.uk" claiming to be http://www.alasdairjggray.co.uk
> > ORCID: http://orcid.org/0000-0002-5711-4872
> > Telephone: +44 131 451 3429
> > Twitter: @gray_alasdair
> >
> >
> >
> >
> >
> >
> > ________________________________
> >
> > Sunday Times Scottish University of the Year 2011-2013
> > Top in the UK for student experience
> > Fourth university in the UK and top in Scotland (National Student Survey
> > 2012)
> >
> > We invite research leaders and ambitious early career researchers to
> join us
> > in leading and driving research in key inter-disciplinary themes. Please
> see
> > www.hw.ac.uk/researchleaders for further information and how to apply.
> >
> > Heriot-Watt University is a Scottish charity registered under charity
> number
> > SC000278.
>
>
>
> --
> Jerven Bolleman
> me@jerven.eu <javascript:;>
>
>