Verifiability

  1. Verifying authenticity of the dataset
  2. Verifying publisher information
  3. Verifying usage of digital signatures

Verifying authenticity of the dataset

For recover the vocabularies used in the KG we can use two different approach. The first is try to parse the VoID file if available and we have to search the triples with the $void:vocabulary$ triples. The second method is to use the following query on the SPARQL endpoint.

PREFIX void: <http://rdfs.org/ns/void#>
SELECT DISTINCT ?o
WHERE{?s void:vocabulary ?o }

To quantize this metric we need to recover all terms used in the KG. We use the query illustred here, then we determine the vocabulary from which each term comes and we put the number into the $namespaces$ variable. Lastly, to quantize the metric we use the following formula, where $vocabs$ is the output of the first query:

\[m_{vocabs} = \frac{vocabs}{namespace}\]

Verifying publisher information

Authors

Also the authors can be recovered via the VoID file or the SPARQL endpoint. In the VoID file we have to search the triples with the predicate equals to $dcterms:creator$. As alternative, we execute the following query on the SPARQL endpoint.

PREFIX dc: <http://purl.org/dc/elements/1.1/>
PREFIX dcterms: <http://purl.org/dc/terms/>
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
PREFIX dct: <http://purl.org/dc/terms/>
SELECT DISTINCT ?o
WHERE{
{?s dc:creator ?o }
UNION
{?s dcterms:creator ?o}
UNION
{?s foaf:maker ?o}
UNION
{?s dct:creator ?o}
}

To quantize this metric, we assign 1 if authors are indicated, 0 otherwise.

Contributors

This metric is recoverable by searching the $dcterms:contributor$ predicate in the VoID file or by executing the following query on the SPARQL endpoint:

PREFIX dcterms:<http://purl.org/dc/terms/>
SELECT DISTINCT ?o
WHERE {?s dcterms:contributor ?o.}

To quantize this metric, we assign 1 if contributors are indicated, 0 otherwise.

Publishers

The metric is calculated by searching the $dcterms:publisher$ predicate in the VoID file or by executing the following query on the SPARQL endpoint:

PREFIX dc: <http://purl.org/dc/elements/1.1/>
PREFIX dct: <http://purl.org/dc/terms/>
SELECT DISTINCT ?o
WHERE {
{?s dc:publisher ?o}
UNION
{?s dct:publisher ?o}
}

To quantize this metric, we assign 1 if publichers are indicated, 0 otherwise.

Sources

For this metric we analyze the KG metadata and in particular we get the value from the field that has as key $sources$ . To quantize this metric, we assign 1 if sources is indicated, 0 otherwise.

Verifying usage of digital signatures

To check and retrieve the signature on the KG if present, the following query is executed:

PREFIX swp:<http://www.w3.org/2004/03/trix/swp-2/>
SELECT ?s ?o
WHERE{
{?s swp:signature ?o}
UNION
{?s swp:authority ?o}
UNION
{?s swp:certificate ?o}
UNION
{?s swp:quotedBy ?o}
UNION
{?s swp:assertedBy ?o}
}

To quantize this metric, we assign 1 if there is a signature, 0 otherwise.