376 questions
2
votes
0
answers
57
views
Why does this query timeout while this similar one does not?
I wanted to know for each president, in what state were they born, so I wrote this Wikidata query:
SELECT * WHERE {
# P31 = instance of
# Q5 = human (excludes fictional characters)
?president ...
- 5,583
0
votes
0
answers
28
views
Linked data: relative URIs of fragments
I am working on an Linked Data / RDF implementation. Following https://www.w3.org/TR/ldp-bp/#use-relative-uris I would like to use relative URIs in sub-graphs. (NOTE that while the referenced best ...
- 980
0
votes
1
answer
63
views
Using RDF nodes from W3C standards in Linked Data ontologies
Is it good/tolerable practice to use elements from W3C standards in a (wannabe five-star) Linked Open Data Ontology?
For example, there is fo:region-body, which is an element of the XSL-FO standard (...
- 938
1
vote
0
answers
58
views
BPMN process engine which consumes data from KGs
I am involved in a project and I would like to ask for some advice, opinion, ideas...
The thing is that we have some data stored in a triple-store (GraphDB), with some related ontologies, SHACL rules ...
- 41
1
vote
1
answer
170
views
Import object properties in OWL ontology
I am a beginner in Linked Data and ontologies. I import CIDOC ontology to mine, in order to use some of its classes and properties. I have an owl file and in ttl syntax, I do
@prefix cidoc: <http://...
- 3,976
0
votes
0
answers
32
views
Which geometry serializations to include in GeoSPARQL RDF?
I am generating RDF triples for a dataset, and want to support GeoSPARQL. Given a geo:Geometry, multiple geometry serializations can be attached. Some of the options include geo:asGeoJSON, geo:asWKT, ...
- 1,588
0
votes
0
answers
65
views
Generate OWL from RDF generated data
I have simple relational database tables
drugs (drug_id(PK), traditional_name, category, factory_id(FK) ....)
chemical composition (Id(PK), scientific_name, ... )
drugs_compositions (Id(pk), drug_id, ...
- 6,566
1
vote
0
answers
129
views
Is there a way to prevent WebVOWL creating undefined union classes?
I'm working on a digital humanities project where I'm trying to use WebVowl to visualise an ontology I made in Protégé. When I import the ontology into WebVowl it generates a lot of undefined union ...
- 11
1
vote
1
answer
104
views
How to set up the ID of a json element in rdflib
Context
I am loading a rdf file in rdflib, and am trying to export it in json-ld.
The original rdf looks like:
<cim:Substation rdf:ID="_1234">
<cim:IdentifiedObject.name>A ...
- 3,081
1
vote
0
answers
82
views
With multiple SERVICE clauses and large numbers of relationships in the path, how to execute SPARQL federated query statement?
Regarding the following SPARQL federated query statements:
There are over 10000 ?s2 related to ?s1
There are over 10000 ?s3 related to the previously found ?s2
There are over 10000 ?s4 related to the ...
- 75
1
vote
0
answers
211
views
What's the principle of SPARQL `SERVICE` clause query?
I know that SPARQL federated query engine (such as Jena) decomposes it into individual SPARQL based on Service, then sends it to the specified SPARQL endpoint for execution, and finally combines the ...
- 75
0
votes
0
answers
37
views
DBPedia Query not returning All I need
I want to retrieve from DBpedia all the states and territories in India as well as all the cities contained in them. I have a long query that does a UNION and returns the territories but not any ...
- 139
1
vote
1
answer
80
views
What is the logic of the SPARQL CONSTRUCT LIMIT?
What is the logic of LIMIT when using CONSTRUCT queries in SPARQL?
When I use CONSTRUCT to query DBpedia, I find that the results sometimes don't match the LIMIT
Example
SPARQL:
CONSTRUCT {
?s a ?...
- 75
1
vote
1
answer
116
views
Specify subframe for elements of id-value property map in a JSON-LD frame
I am trying to write a JSON-LD frame that serializes some RDF documents in a consistent way. Currently, the RDF is being parsed out from JSON-LD that is correctly structured and I would like the frame ...
- 1,440
1
vote
1
answer
613
views
Is the Knowledge Graph and the Linked Open Data the same thing?
I started to dive into the topic "Knowledge Graph" and I get the feeling that this is the same as the "Linked Open Data". I have some questions 1) If so, why did they need to ...
- 458
0
votes
0
answers
93
views
Are there some Linked data websites use distributed sparql Endpoints and provide cross-domain data search services?
Is there a website x:
Searching rdf resources from distributed sparql Endpoints.
Rdf resources come from multiple subject areas and are related .
Provide some semantic services such as QA, route ...
- 75
1
vote
0
answers
67
views
Rdflib and activitystreams
so I'm investigating rdflib to use with ActivityStreams. My current main goal is to input an Object and get the same one back!
My current try looks like this
import rdflib
G = rdflib.Graph()
G.parse('...
- 111
4
votes
1
answer
430
views
SHACL - Attribute is optional, but if it exists, it has to have once a specific value
a class has an optional attribute. If you use this attribute, you have to set it once to a specific value. All other uses of this attribute are not restricted.
The real world example is dcat:...
- 41
0
votes
1
answer
57
views
Wikidata SPARL query by generic property return object instead of statement
I want to disseminate the query by spreading the nodes like in the below query.
SELECT ?item ?itemLabel ?prop ?object ?objectLabel ?prop2 ?object2
WHERE
{
VALUES (?item) { (wd:Q12418)}
?item ?...
- 1,395
0
votes
2
answers
699
views
Using shacl to validate a property that has at most one value in its properties
I'm trying to create a shacl based on the ontology that my organization is developing (in dutch): https://wegenenverkeer.data.vlaanderen.be/
The objects described have attributes (properties), that ...
0
votes
2
answers
135
views
How does SPARQL queries automatically read namespaces for abbreviations in virtuoso?
I've set up some namespaces in virtuoso, but when I used jena to do sparql queries in virtuoso, some namespaces were not abbreviated:
@prefix sio: http://semanticscience.org/resource/SIO_ .
@...
- 75
1
vote
2
answers
2k
views
The process of creating knowledge graphs [closed]
So I am new to the world of the semantic web, RDF's and Ontologies
How does the process of creating knowledge graphs work?
Say I want to create knowledge graphs about a specific team and link ...
user15793405
2
votes
1
answer
592
views
How do I define a custom @context for a verifiable credential?
Here is an example of a verifiable credential I want to create
{
"@context": ["https://www.w3.org/2018/credentials/v1"],
"credentialSubject": {
"id": &...
- 308
0
votes
1
answer
66
views
Whether cross-domain URIs are supported by rdflib.js? [duplicate]
Whether cross-domain URIs are supported by rdflib.js?
The following URIs are not parsed by fetcher.nowOrWhenFetched:
https://www.w3.org/2000/01/rdf-schema#
https://www.dublincore.org/specifications/...
- 75
1
vote
1
answer
209
views
How to get RDF data returned by remote HTTP IRI through linux curl (e.g. DBpedia, GENEPIO ...)?
I know that the following remote HTTP IRI can be parsed directly with 'curl http://xxx' because they return RDF data directly:
https://www.w3.org/1999/02/22-rdf-syntax-ns#
http://www.w3.org/2000/01/...
- 75
-1
votes
2
answers
316
views
How to parse arbitrary RDF IRI through javascript?
RDF IRI such as:
https://www.w3.org/1999/02/22-rdf-syntax-ns
https://www.dublincore.org/specifications/dublin-core/dcmi-terms/dublin_core_terms.ttl
http://dbpedia.org/resource/...
- 75
0
votes
1
answer
193
views
How do linked open data datasets linked together?
I'm learning about RDF databases and the concept of "Linked Open Data (LOD)". According to what Wiki saids about LOD, many open-accessible datasets are published online and some of the ...
- 421
0
votes
0
answers
54
views
How to discover the paths of two nodes in an endpoint or different endpoints
How to discover the paths of two nodes in an endpoint, preferably the paths of different endpoints. Can sparql be implemented , or is there any other way to do it
- 1
0
votes
1
answer
730
views
How can I only download the individuals that I have created in Protégé?
I like to download the individuals that I have created in Protégé and upload them in GraphDB as a file. When I downloaded the whole ontology, I saw that the individuals were also downloaded in the XML/...
- 145
0
votes
2
answers
100
views
How to show "2022-09-12T00:00:01"^^xsd:dateTime only as 2022-09-12 or at least without ^^xsd:dateTime in my SPARQL results?
How to show "2022-09-12T00:00:01"^^xsd:dateTime only as 2022-09-12 or at least without ^^xsd:dateTime in my SPARQL results?
- 145
0
votes
0
answers
88
views
Sequence with conditional nodes in OWL
I want to represent a sequence of action in OWL using protege. What I want to be able to represent is statement like : "if this action is true, then the next action is X. If it's false, then the ...
- 3
0
votes
0
answers
346
views
Adding and storing json-ld to an existing website / database
I've seen that there is a vote for a close request because the question is too broad. Let me rewrite the question:
There is a need to add metadata to different database tables (and thus records) which ...
- 18.7k
2
votes
1
answer
435
views
retrieving the countries details from geonames using a sparql query
I am trying to get specific countries informations from geonames using "Linked Data HTW Chur sparql endpoint" (url: http://linkeddata.fh-htwchur.ch/lodestar/sparql ):
PREFIX gn: <http://...
- 99
0
votes
1
answer
61
views
Cannot create blank nodes from D2RQ mapping
I have one table (FCT_POPULATION) with the following structure, representing a quantity of a range over the years for a single city. So, in the same year, I have two quantities, varying according to a ...
- 87
1
vote
2
answers
591
views
skos:related vs skos:relatedMatch
Can someone explain to me the difference between skos:related and skos:relatedMatch predicates? My current understanding is that skos:related applies to concepts that are related "within" a ...
- 569
0
votes
1
answer
213
views
Sequence in OWL using protege
I'm trying to define a sequence of action in OWL using protege. I have read the following topics:
Modelling sequence order in OWL-DL ontology
Assigning sequence in OWL using Protege
The problem I ...
- 3
0
votes
1
answer
174
views
JSON schema nesting based on linked data
I've dataset pulled from a linked data platform.
The dataset looks like this:
label
relationClass
Organization
Department
Department
Employee
I want to create a JSON Schema based on this data where ...
- 81
2
votes
1
answer
242
views
Why does Activity Pub make servers wrap "Note" objects into "Create" activities?
What I've gathered is that new posts are published by POSTing a JSON-LD Activity Streams object of type Note to an actor's outbox.
{"@context": "https://www.w3.org/ns/activitystreams&...
- 357
1
vote
1
answer
201
views
SPARQL Federated Query takes too long to respond
I have a SPARQL federated query where I join data from wikidata and dbpedia. When I run the first two queries it takes reasonable time. However, when I add the 3rd service it takes too much time. In ...
- 1,395
-1
votes
1
answer
425
views
How to import multiple ontologies into neo4j with multiple labels for the owl:Class
I have 3 ontologies and I want to import them in the same graph in neo4j, but I would like to import each owl:Class of each ontology under a different label.
Any guidance or suggestions are greatly ...
- 177
0
votes
0
answers
90
views
Sparql Querty to DBpedia endpoint
I am new to SPARQL, and I need to write Sparql query to retrieve all the entities and links that DBpedia use from the Ordnance Survey ontologies.
In words, I need to find out, how DBpedia is linked ...
- 53
1
vote
1
answer
239
views
Alias a JSON-LD keyword and simultaneously provide a @context for it
I have the following JSON document (based on GitHub API output):
{
"@id": "https://github.com/octadocs/octadocs",
"license": {
"key": "mit",
...
- 1,772
0
votes
1
answer
49
views
Realizing and Retrieving information from a producer-consumer OWL model
I have the following scenario modelled in OWL:
Producer ----producesResource---> Resource <------consumesResource ---- Consumer
Producer, Resource and Consumer are OWL Classes, while ...
- 346
3
votes
1
answer
4k
views
URI to identify certificates
Are there some commonly used or standardized URI schemes or patterns that are used to identify SSL certificates, for example for description in linked data applications? The URI does not necessarily ...
- 13.5k
1
vote
0
answers
126
views
How to import the OWL classes as a Node in Neo4j?
I am working on Neo4j, and I imported my ontology, but I didn't understand how Neo4j import the class owl:NamedIndividual or the other class other than owl:Class, because it gives me just one node ...
- 177
0
votes
2
answers
646
views
Title Case Conversion in SPARQL Query with REGEX
I am one inch away from the solution to my problem. I am attempting title case conversion of strings retrieved via SPARQL. I am using the REPLACE function in combination with LCASE and REGEX:
BIND (...
- 15
0
votes
1
answer
212
views
How to match on non-existence of property and not output a default value in JSON-LD framing?
I have a graph of schema:ProductGroup and schema:ProductModel nodes, and I've written a frame to output it in a nested structure, conceptually similar to the library-book-chapter examples. Everything ...
- 5,694
1
vote
0
answers
144
views
How best to describe material of parts of a schema.org/Product in JSON-LD?
The schema.org/Product type has a material property for “[the] material that something is made from.” I'd like to describe the materials that each part of a product is made from.
For example, suppose ...
- 5,694
0
votes
0
answers
176
views
Sparql: Query DBPedia and follow redirects
I'm trying to query DBPedia for some animal pictures.
The species I'm querying for is Pan_troglodytes. When one visits https://en.wikipedia.org/wiki/Pan_troglodytes in a browser, one gets redirected ...
- 27.9k
1
vote
1
answer
66
views
How to compact an @id?
Is it possbile to compact iris in @id via the context?
I didn't found a solution for that, without using @base.
{
"@context": {
"MaxMustermann": "http://...
- 35