Archivo - Ontology Rating

Archivo Star Rating

Automatic Ontology Discovery

Each week DBpedia Archivo follows links from the known part of the Semantic Web to discover more ontologies. For that Archivo uses different methods of finding Non-Information Resources (NIR) of vocabularies. NIRs act as the representation of the ontology on the web and should lead, either directly or by redirection to the RDF content of the ontology. Discovery source is shown either in the archive or the ontology view.

<$non-information-resource> rdf:type owl:Ontology .
# OR
<$non-information-resource> rdf:type skos:ConceptScheme .

NIR Discovery Sources:

LOV: A straightforward way of discovering ontology URIs is by crawling ontology repositories, in Archivos case it is Linked Open Vocabularies
prefix.cc: Often prefixes are non information resources, so crawling prefix.cc yields good results.
VOID mod: To discover the ontologies data on the DBpedia Databus uses, Archivo crawls the VoID from the databus for NIRs.
SPOs: To discover ontologies used by vocabularies, Archivo crawls all URIs from the Subjects, Predicates and Objects of Archivos ontologies for further potential non information resources.
user-suggestions: If neither of these methods can find a certain ontology, the NIR of the vocabulary can be added here and Archivo handles the rest.

All these ontologies get updated regularily three times a day (currently 02:00 am, 10:00 am and 06:00 pm).

Archivo Stars

The Archivo Stars provide additional tests to check the fitness of the vocabulary for the semantic web. This section explains how to quickly fix problems with a vocabulary to earn all four Archivo Stars.

★ Retrieval & Parsing

This star is granted if the ontology is retrievable from its non-information resource and parses correctly.

Retrieval: Archivo retrieves the RDF content of an ontology by testing different Accept Headers (currently supported: RDF+XML, Turtle and N-Triples) and takes the one which yields the most triples (see code).
Archivo processes the ontology, if it follows the recommendations of the W3C for publishing RDF vocabularies. Some rules are relaxed by Archivo, as long as it is deterministic.

Parsing: After retrieval succeeded, Archivo parses the syntax of the different formats of the ontology. Parsing is greedy, we extract all triples until an error is found (warnings are ignored, but should also be fixed). If an owl:Ontology or skos:ConceptScheme is found in the parsed triples, the ontology is added to Archivo, but no star is awarded, if errors were found. Otherwise, Archivo discards the Ontology. Archivo uses the Raptor RDF library for parsing.

Debugging

sudo apt-get install raptor2-utils
rapper -gc "$non-information-resource"
# example: rapper -gc http://mmoon.org/core#

See also the W3C RDF Validator (check by URI) or cygri's note on Debugging the Semantic Web with CURL.

Limitations & Discussion

Archivo does not (yet) fully support slash ontologies that often only contain the ontology stub at the Non-information URI. Further implementation might analyse links to its classes/properties via http://open.vocab.org/terms/defines an inverse of rdfs:definedBy (cf. http://dbpedia.org/ontology/)
Right now Archivo can only process three different RDF formats (RDF+XML, Turtle and N-Triples), but there are more, like the Manchester Syntax or RDFA

★ License (I & II)

The second and third star are granted for proper and clear license statements and are tested with the Archivo SHACL Library.

License I grants a star for a huge variety of license statements, i.e. when a license is given, but consumers need to spend extra integration effort to understand and use it (cf. License I SHACL test).

License II grants a star for a homogenized license statement: 1. using the property dct:license and a URI as object. (cf. License II SHACL test).

★★☆☆ Licenses
Count license-property license

190 <http://creativecommons.org/ns#license> <http://creativecommons.org/licenses/by/4.0/deed.en_US>
52 <http://creativecommons.org/ns#license> <http://creativecommons.org/licenses/by-sa/3.0/> 
40 <http://creativecommons.org/ns#license> <http://creativecommons.org/licenses/by/3.0/> 
27 <http://purl.org/dc/elements/1.1/license> <https://creativecommons.org/licenses/by-sa/4.0/> 
20 <http://creativecommons.org/ns#license> <http://creativecommons.org/licenses/by/4.0/>
8 <http://creativecommons.org/ns#license> <https://creativecommons.org/licenses/by-nc/4.0/> 
8 <http://creativecommons.org/ns#license> <http://creativecommons.org/publicdomain/zero/1.0/> 
7 <http://purl.org/dc/terms/license> "https://www.gleif.org/en/meta/lei-data-terms-of-use/"^^<http://www.w3.org/2001/XMLSchema#anyURI 
7 <http://creativecommons.org/ns#license> <http://www.data.gouv.fr/Licence-Ouverte-Open-Licence> 
6 <http://creativecommons.org/ns#license> <https://creativecommons.org/licenses/by/4.0/> 
6 <http://creativecommons.org/ns#license> <https://creativecommons.org/licenses/by/3.0/> 
6 <http://creativecommons.org/ns#license> "http://creativecommons.org/licenses/by/3.0/"^^<http://www.w3.org/2001/XMLSchema#anyURI
5 <http://www.w3.org/1999/xhtml/vocab#license> <http://creativecommons.org/licenses/by/4.0/deed.en_US> 
5 <http://purl.org/dc/terms/license> "http://creativecommons.org/licenses/by-nc-sa/2.0/" 
5 <http://creativecommons.org/ns#license> <http://opendatacommons.org/licenses/by/> 
5 <http://creativecommons.org/ns#license> <http://creativecommons.org/licenses/by/2.0/> 
4 <http://creativecommons.org/ns#license> <https://creativecommons.org/publicdomain/zero/1.0/>
3 <http://www.w3.org/1999/xhtml/vocab#license> <http://creativecommons.org/licenses/by-sa/2.0/uk/> 
3 <http://www.w3.org/1999/xhtml/vocab#license> <http://creativecommons.org/licenses/by/1.0/> 
3 <http://schema.org/license> <http://creativecommons.org/licenses/by-sa/3.0/> 
2 <http://purl.org/dc/terms/license> "https://creativecommons.org/licenses/by/4.0" 
2 <http://purl.org/dc/terms/license> "https://creativecommons.org/licenses/by/4.0/"
2 <http://purl.org/dc/elements/1.1/license> "http://creativecommons.org/publicdomain/zero/1.0/" 
2 <http://purl.org/dc/elements/1.1/license> <http://creativecommons.org/licenses/by/3.0/> 
2 <http://creativecommons.org/ns#license> <http://unlicense.org> 
2 <http://creativecommons.org/ns#license> <https://creativecommons.org/licenses/by-sa/4.0/> 
2 <http://creativecommons.org/ns#license> <https://creativecommons.org/licenses/by-nc-sa/2.0/>
2 <http://creativecommons.org/ns#license> "http://purl.org/NET/rdflicense/cc-by4.0"^^<http://www.w3.org/2001/XMLSchema#string 
2 <http://creativecommons.org/ns#license> <http://creativecommons.org/licenses/by-nc/4.0/>
1 <http://www.w3.org/1999/xhtml/vocab#license> <http://creativecommons.org/licenses/by/4.0/> 
1 <http://www.w3.org/1999/xhtml/vocab#license> <http://creativecommons.org/licenses/by/3.0/> 
1 <http://www.w3.org/1999/xhtml/vocab#license> <http://creativecommons.org/licenses/by/2.5/ca/> 
1 <http://www.ontologyrepository.com/CommonCoreOntologies/content_license> <https://creativecommons.org/licenses/by/3.0/> 
1 <http://www.ontologyrepository.com/CommonCoreOntologies/code_license> <https://opensource.org/licenses/BSD-3-Clause> 
1 <https://creativecommons.org/ns#license> <https://creativecommons.org/publicdomain/zero/1.0/> 
1 <https://creativecommons.org/ns#license> <https://creativecommons.org/licenses/by/4.0/>
1 <https://creativecommons.org/ns#licence> <https://creativecommons.org/licenses/by/3.0/> 
1 <http://schema.org/license> <http://creativecommons.org/licenses/by/4.0/deed.en_US> 
1 <http://purl.org/dc/terms/license> "www.apache.org/licenses/LICENSE-2.0"^^<http://www.w3.org/2001/XMLSchema#string 
1 <http://purl.org/dc/terms/license> "https://creativecommons.org/licenses/by/3.0/"^^<http://www.w3.org/2001/XMLSchema#string 
1 <http://purl.org/dc/terms/license> "https://creativecommons.org/licenses/by/3.0/" 
1 <http://purl.org/dc/terms/license> "https://creativecommons.org/licenses/by/1.0" 
1 <http://purl.org/dc/terms/license> "http://creativecommons.org/licenses/by-nc-sa/3.0/"^^<http://www.w3.org/2001/XMLSchema#string
1 <http://purl.org/dc/terms/license> "http://creativecommons.org/licenses/by/4.0/"^^<http://www.w3.org/2001/XMLSchema#string 
1 <http://purl.org/dc/terms/license> "http://creativecommons.org/licenses/by/4.0/" 
1 <http://purl.org/dc/terms/license> "http://creativecommons.org/licenses/by/3.0/"@en 
1 <http://purl.org/dc/terms/license> "CC-BY"^^<http://www.w3.org/2001/XMLSchema#string 
1 <http://purl.org/dc/elements/1.1/license> "This document is available under Creative
                        Common License. You are free to Share \u2014 to copy, distribute, display, and perform the work and to Remix \u2014 to make derivative works; under the condition of Attribution: You must attribute the work in the manner specified
                        by the author or licensor (but not in any way that suggests that they endorse you or your use of the work). The publisher does not accept any liability for the inaccuracies in this document."@en 1 <http://purl.org/dc/elements/1.1/license>
                        <https://creativecommons.org/licenses/by/4.0/> 1 <http://purl.org/dc/elements/1.1/license> <https://creativecommons.org/licenses/by/1.0/> 1 <http://purl.org/dc/elements/1.1/license> <http://creativecommons.org/licenses/by/3.0/it/>
                        1 <http://purl.org/dc/elements/1.1/license> "http://creativecommons.org/licenses/by/3.0/" 1 <http://purl.org/dc/elements/1.1/license> "<http://creativecommons.org/licenses/by/2.0/ 1 <http://creativecommons.org/ns#license>
                        <http://www.w3.org/Consortium/Legal/2002/copyright-software-20021231.html> 1 <http://creativecommons.org/ns#license> "http://www.apache.org/licenses/LICENSE-2.0"^^<http://www.w3.org/2001/XMLSchema#string 1 <http://creativecommons.org/ns#license>
                        <http://www.apache.org/licenses/LICENSE-2.0> 1 <http://creativecommons.org/ns#license> <https://www.gnu.org/licenses/agpl-3.0.en.html> 1 <http://creativecommons.org/ns#license> <https://www.apache.org/licenses/LICENSE-2.0>
                        1 <http://creativecommons.org/ns#license> <https://spdx.org/licenses/BSD-3-Clause> 1 <http://creativecommons.org/ns#license> <http://opendatacommons.org/licenses/odbl/1.0/> 1 <http://creativecommons.org/ns#license>
                        <http://creativecommons.org/publicdomain/mark/1.0/> 1 <http://creativecommons.org/ns#license> <http://creativecommons.org/licenses/by-sa/4.0/> 1 <http://creativecommons.org/ns#license> <http://creativecommons.org/licenses/by-sa/2.0/uk/deed.en_GB>
                        1 <http://creativecommons.org/ns#license> <http://creativecommons.org/licenses/by-nc-sa/3.0/> 1 <http://creativecommons.org/ns#license> "http://creativecommons.org/licenses/by/4.0/"^^<http://www.w3.org/2001/XMLSchema#string
                        1 <http://creativecommons.org/ns#license> "<http://creativecommons.org/licenses/by/4.0/ 1 <http://creativecommons.org/ns#license> <http://creativecommons.org/license/by/3.0/> 1 <http://creativecommons.org/ns#license>
                        "Copyright (c) 2016-2018 Monge Roffarello Alberto\n\n Licensed under the Apache License, Version 2.0 (the \"License\");\n you may not use this file except in compliance with the License.\n You may obtain a copy of the License at\n\n
                        http://www.apache.org/licenses/LICENSE-2.0\n\n Unless required by applicable law or agreed to in writing, software\n distributed under the License is distributed on an \"AS IS\" BASIS,\n WITHOUT WARRANTIES OR CONDITIONS OF ANY
                        KIND, either express or implied.\n See the License for the specific language governing permissions and\n limitations under the License" 1 <http://creativecommons.org/ns#license> "Copyright (c) 2008-2019 Dario Bonino\n\nLicensed
                        under the Apache License, Version 2.0 (the \"License\");\nyou may not use this file except in compliance with the License.\nYou may obtain a copy of the License at\n\n http://www.apache.org/licenses/LICENSE-2.0\n\nUnless required
                        by applicable law or agreed to in writing, software\ndistributed under the License is distributed on an \"AS IS\" BASIS,\nWITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\nSee the License for the specific
                        language governing permissions and\nlimitations under the License"^^<http://www.w3.org/2001/XMLSchema#string 1 <http://creativecommons.org/ns#license> "Attribution-NoDerivatives 4.0 International (CC BY-ND 4.0)" 1 <http://creativecommons.org/ns#license>
                        "Academic Free License (\"AFL\") 3.0" 1 <http://creativecommons.org/ns#licence> <http://www.datagouv.fr/Licence-Ouverte-Open-Licence> 1 <http://creativecommons.org/ns#licence> "http://creativecommons.org/licenses/by-sa/3.0/"
                        1 <http://creativecommons.org/ns#licence> <http://creativecommons.org/licenses/by-sa/3.0/>

★★★☆+ Licenses
Count license-property license

41 <http://purl.org/dc/terms/license> <http://purl.allotrope.org/voc/iupac-license>
35 <http://purl.org/dc/terms/license> <http://creativecommons.org/licenses/by/3.0/>
14 <http://purl.org/dc/terms/license> <https://www.apache.org/licenses/LICENSE-2.0>
13 <http://purl.org/dc/terms/license> <http://creativecommons.org/publicdomain/zero/1.0/> 
13 <http://purl.org/dc/terms/license> <http://creativecommons.org/licenses/by/4.0/> 
10 <http://purl.org/dc/terms/license> <https://forge.etsi.org/etsi-software-license> 
10 <http://purl.org/dc/terms/license> <https://creativecommons.org/licenses/by/4.0/> 
8 <http://purl.org/dc/terms/license> <http://www.opendatacommons.org/licenses/pddl/1.0/>
8 <http://purl.org/dc/terms/license> <https://creativecommons.org/licenses/by-sa/4.0/> 
7 <http://purl.org/dc/terms/license> <https://w3id.org/italia/controlled-vocabulary/licences/A31_CCBYSA40> 
7 <http://purl.org/dc/terms/license> <http://creativecommons.org/licenses/by-sa/4.0/> 
5 <http://purl.org/dc/terms/license> <https://overheid.vlaanderen.be/sites/default/files/documenten/ict-egov/licenties/hergebruik/modellicentie_gratis_hergebruik_v1_0.html>
5 <http://purl.org/dc/terms/license> <http://purl.org/NET/rdflicense/cc-by4.0> 
5 <http://purl.org/dc/terms/license> <http://purl.allotrope.org/voc/creative-commons-attribution-license> 
4 <http://purl.org/dc/terms/license> <http://www.apache.org/licenses/LICENSE-2.0> 
4 <http://purl.org/dc/terms/license> <https://joinup.ec.europa.eu/category/licence/isa-open-metadata-licence-v11> 
4 <http://purl.org/dc/terms/license> <https://creativecommons.org/publicdomain/zero/1.0/>
3 <http://purl.org/dc/terms/license> <https://creativecommons.org/licenses/by/1.0/> 
3 <http://purl.org/dc/terms/license> <http://creativecommons.org/licenses/by-sa/3.0/> 
3 <http://purl.org/dc/terms/license> <http://creativecommons.org/licenses/by-sa/2.0/uk/> 
3 <http://purl.org/dc/terms/license> <http://creativecommons.org/licenses/by/4.0> 
2 <http://purl.org/dc/terms/license> <http://www.w3.org/Consortium/Legal/2015/copyright-software-and-document>
2 <http://purl.org/dc/terms/license> <http://www.opengeospatial.org/ogc/Software> 
2 <http://purl.org/dc/terms/license> <http://creativecommons.org/licenses/by/4.0#id> 
2 <http://purl.org/dc/terms/license> <http://creativecommons.org/licenses/by/3.0/au/>
2 <http://purl.org/dc/terms/license> <http://creativecommons.org/licenses/by/2.0/> 
1 <http://purl.org/dc/terms/license> <http://www.omg.org/techprocess/ab/SpecificationMetadata/MITLicense> 
1 <http://purl.org/dc/terms/license> <http://www.gnu.org/licenses/lgpl.html> 
1 <http://purl.org/dc/terms/license> <https://www.w3.org/Consortium/Legal/2002/ipr-notice-20021231#Copyright/> 
1 <http://purl.org/dc/terms/license> <https://www.apache.org/licenses/LICENSE-2.0/>
1 <http://purl.org/dc/terms/license> <https://github.com/madhawap/human-device-gesture-interaction-ontology/blob/master/LICENSE> 
1 <http://purl.org/dc/terms/license> <https://creativecommons.org/licenses/by-sa/3.0/it/>
1 <http://purl.org/dc/terms/license> <https://creativecommons.org/licenses/by-nc/4.0/> 
1 <http://purl.org/dc/terms/license> <https://creativecommons.org/licenses/by/3.0/> 
1 <http://purl.org/dc/terms/license> <http://jazz.net/ns/license.html> 
1 <http://purl.org/dc/terms/license> <http://creativecommons.org/publicdomain/zero/1.0/legalcode.ja> 
1 <http://purl.org/dc/terms/license> <http://creativecommons.org/licenses/by-sa/4.0>
1 <http://purl.org/dc/terms/license> <http://creativecommons.org/licenses/by-nc-sa/3.0/> 
1 <http://purl.org/dc/terms/license> <http://creativecommons.org/licenses/by-nc-sa/2.0/> 
1 <http://purl.org/dc/terms/license> <http://creativecommons.org/licenses/by-nc/4.0/> 
1 <http://purl.org/dc/terms/license> <http://creativecommons.org/licenses/by/1.0#id> 
1 <http://purl.org/dc/terms/license> <http://creativecommons.org/licenses/by/1.0/>
1 <http://purl.org/dc/terms/license> <file:///tmp/workspace/ttl/http://example.com/TODO>

Debugging

We encountered these common problems:

Confusing dct (http://purl.org/dc/terms/) with dc (http://purl.org/dc/elements/1.1/), because there is no property named dc:license.
Misspelling of license, as licence in property
Note: If an ontology already has a license statement, there is no need to delete it, just add another one with dct:license.

# Pattern for accepted License II statement
@prefix owl: <http://www.w3.org/2002/07/owl#> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix dct: <http://purl.org/dc/terms/> .

<$non-information-resource> a owl:Ontology;
    dct:license <$license-uri> .

Limitations & Discussion

Future work will aim at improving underspecification. We are in close contact with the Dalicc project to employ clear, unambiguous, machine understandable licenses .

We are further investigation the legal consequences of having several license statements, which introduces ambiguity, i.e. can the user choose? can they be merged?
The criteria for the License II star might be more strict in the future, requiring a machine-readable, resolvable URI or a URI that can be owl:sameAs linked to a machine-readable, resolvable URI.

★ Consistency

The fourth star is granted for logical consistency of the ontology (tested with Stardog/Pellet).

Debugging

Test using Pellet CLI. Archivo also provides the Pellet report, available at the Archivo ontology view at the failed consistency check symbol ✘ where the logical inconsistencies can be seen and fixed.

Limitations & Discussions

Stardog's Pellet sometimes crashes (example) for unknown reasons. We are investigating.
We only integrated one reasoner implementation (Pellet) into Archivo at the moment. Ideally, several different reasoners should do a consistency check. This way, the interoperability of the ontology can e guaranteed.

Help improving the Web of Ontologies

SHACL tests

SHACL (https://www.w3.org/TR/shacl/, co-edited by DBpedia’s CTO D. Kontokostas) enables easy testing of ontologies. Archivo offers free SHACL continuous integration testing for ontologies. Anyone can implement their SHACL tests and add them to the SHACL library on Github. We believe that there are many synergies, i.e. SHACL tests for your ontology are helpful for others as well. Some ideas: Check for labels/comments, Check for multilinguality (i.e. labels in more than 5 languages), check for properties you consider essentiel. Add a file to github and we will run it.

Application compliance

Applications often pose certain requirements to the ontology. Archivo allows to SHACL them up and test for them. An example for such an compliance check is the LODE conformity check, which measures if an ontology can be documented well using the Live OWL Documentation Environment (LODE) service. If the LODE SHACL test fails, it shows that some of the features of LODE will not work.

Discuss Archivo's Future Features

We are open for feedback and are setting up a steering committee to further improve the overall integrity of the de-central web of ontologies.
Discussions: Github Issues
Questions: DBpedia Forum

Feedback and changes addressed:

Sep 2020: we would like to thank the reviewers of SEMANTiCS 2020 to explain the importance of including SKOS. We now allow skos:ConceptScheme on NIR's in Archivo.