Re: How to express nominal dqv:values?

Hi Vladimir,


>
> A small mistake in
> http://w3c.github.io/dwbp/vocab-dqg.html#expressQualityDerivation:
>
> :measurement3  prov:wasDerivedFrom measurement2, measurement3 ;
> should be
> :measurement3  prov:wasDerivedFrom measurement1, measurement2 ;
>


Thanks, this is now fixed!


>
> Now back to the subject. So in effect instead of this:
> /------------
> ms:accuracy a dqv:Metric;
[...]
>
> ms-content:b3f35 dqv:hasQualityMeasurement ms-content:b3f35-quality.
> ms-content:b3f35-quality a dqv:QualityMeasurement ;
>     dqv:isMeasurementOf ms:accuracy; dqv:value ms:accuracy-curated.
> \-------------
>
> You suggest to use that:
> /-------------
> ms:Accuracy a skos:ConceptScheme;
>    rdfs:label "Accuracy values"@en.
> ms:accuracy-low a skos:Concept; skos:inScheme ms:Accuracy;
>    skos:prefLabel "Low accuracy"@en.
> ms:accuracy-medium a skos:Concept; skos:inScheme ms:Accuracy;
>    skos:prefLabel "Medium accuracy"@en.
> ms:accuracy-high a skos:Concept; skos:inScheme ms:Accuracy;
>    skos:prefLabel "High accuracy"@en.
> ms:accuracy-curated a skos:Concept; skos:inScheme ms:Accuracy;
>    skos:prefLabel "Manually curated"@en;
>    skos:note "Highest accuracy"@en.
>
> ms-content:b3f35 dqv:hasQualityAnnotation  ms-content:b3f35-quality.
>
> ms-content:b3f35-quality a dqv:QualityAnnotation;
>    dqv:inDimension ldqd:semanticAccuracy;
>    oa:motivatedBy dqv:qualityAssessment;
>    oa:hasTarget ms-content:b3f35;
>    oa:hasBody ms:accuracy-curated.
> \-------------


Yes, maybe lowering the case for ms:Accurary, and maybe typing is as scheme to make the distinction between other types of accuracy resources clearer. Something like ms:accuracyScheme.


>
> I can definitely live with that.


Great!


> It has a redundant link
> (dqv:hasQualityAnnotation  inverse oa:hasTarget)
> but it saves me the need to define "ms:accuracy a dqv:Metric".


NB: dqv:hasQualityAnnotation is not the inverse oa:hasTarget, it's a subproperty of the inverse. I.e. not every oa:hasTarget between A and T implies a dqv:hasQualityAnnotation between T and A.


>
> I think that to the casual reader, the purpose of QualityMeasurement vs
> QualityAnnotation is not obvious.
> Please write some clarification about the difference between the two,
> and emphasize that QualityMeasurement is used with literal values, while
> QualityAnnotation is typically used with resource values.
> It would also be great to give an example with using nominal (resource)
> values for clarification.
>


We can try to add this clarification more prominently. But it's tricky. In the vocabulary overview (section 3) we already have
"The value of a metric can be numeric (e.g., for the metric “human-readable labeling of classes, properties and entities”, the percentage of entities having an rdfs:label or rdfs:comment) or boolean (e.g. whether or not a SPARQL endpoint is accessible)."

Do you think we could add the clarification there, for example changing
[
Besides quality measurements, DQV considers certificates, standards, and quality policies, which can also be organized according to dimensions.
]
into
[
Besides quality measurements, DQV considers annotations (including certificates and user feedback), standards, and quality policies, which can also be organized according to dimensions. As already said, quality measurements are expected to have numeric or boolean values. Annotations and other types of quality assessments listed above can be used with any value, including nominal ones represented as RDF resources, as in section 5.8.
]
Would this be ok? Do you think more should be done? Or something done in another part of the DQV spec?

Especially, about your last comment asking for an example using nominal values. The example in section 5.8 with :three_star is nominal. Isn't this good enough?

Cheers,

Antoine

Received on Sunday, 31 July 2016 23:09:49 UTC