is there any tool that can create RDF statements using the resources of ontologies ?
Yes, the usual suspects: Jena and the Manchester OWLAPI or Rowlex if you're more into Microsofty and .net stuff or even the Redland libraries. If you're more into Python, take a look at RDFLib.
Hope that helps.
Related
How can Jena be used to save triples in a SPARQL endpoint?
I could use SPARQL RestFul API but I wonder if this is also doable using Jena classes.
For SPARQL Update you can do the following:
UpdateRequest update = UpdateFactory.create("# Your SPARQL Updates");
UpdateProcessor processor = UpdateExecutionFactory.createRemote(update, "http://your-domain/update");
processor.execute();
If you are talking about the graph store protocol i.e. uploading entire graphs at once then you can use the DatasetAccessor API e.g.
DatasetAccessor accessor = DatasetAccessorFactory.createHTTP("http://your-domain/ds");
accessor.putModel(m);
If you are talking about MarkLogic specifically (you tagged the question with marklogic), then this github project will likely interest you:
https://github.com/marklogic/marklogic-jena
This library integrates MarkLogic Semantics feature into the Jena RDF
Framework as a persistence and query layer.
Note: not officially released yet currently, but close. Might be worth a look..
HTH!
I'm new in "ontology world". I've been practicing Protegé and ontologies for 2 months and now I would like to understand (and if it is possible to create) a reasoner. But I don't know what is its structure, the language used by it and so on.
Can you please me provide me a piece of information and something to read? Thank you.
The task of a reasoner is to produce inferences. Standard reasoning tasks are consistency check, realization, instance check and satisfiability. You can find all these defined in a number of books and articles about description logic.
Protege uses the OWL API to interface to reasoners so they are implementations of OWLReasoner. Not all of them are written in Java (e.g., FaCT++ is written in C++).
They are quite complex systems, so describing how to implement one takes chapters - too big for an answer here.
I'd recommend exploring the source code of a few of them. Open Source ones, off the top of my head: HermiT, FaCT++, Pellet, JFact, ELK.
I'm working on an OWL ontology and I need some specific issues
I only need ontology schema (TBox) and I got lost, what are the operations that can be
completed using reasoning and sparql and OWL API?
More specifically, I need the following:
1- check cardinalities between classes and properties.
2- find subsumption relationships for a specific class.
3- check whether specific facts hold (e.g. are two classes are disjoint)
4- find the paths (a class-property series) between a set of classes.
What each of reasoning, sparql and OWL API used for? and which one is suitable for my situation?
Actually I don't know how to start and what technique to use.
In addition. Would you please refer me to some reference?
Thanks.
Number 1 is not clear: do you want to know which cardinality axioms are asserted? This can be done without a reasoner. Number 4 is a bit vague as well, can you provide an example?
2, 3 and 5 require a reasoner to be perform accurately.
A reasoner is a program that will explicit implicit information: subsumption, realisation, consistency checks are all operations for which a reasoner is needed. In your tasks, subsumption is clearly needed.
OWLAPI is a Java API to manipulate OWL ontologies; in your case, it could be useful to write the connecting code to use a reasoner for your tasks. Compatible reasoners are Pellet, HermiT, FaCT++, and a few more.
SPARQL is an RDF query language. OWLAPI does not support it. You could use it for your tasks, but they look more OWL oriented than RDF oriented to me. Jena is a Java library supporting RDF, OWL, SPARQL and interfaces with reasoners such as Pellet. Depending on how you decide to solve the above tasks, it might fit more of your requirements than the OWLAPI.
Jena tutorials:
https://jena.apache.org/tutorials/index.html
OWLAPI documentation:
https://github.com/owlcs/owlapi/wiki/Documentation
Is there a way to convert java source directly to equivalent RDF? I am aware of manually creating and java object to RDF/OWL object mapping by Jena API, but I need the automation of the mapping of java source code to RDF/OWL object. Is there any available tool for that?
Thanks in advance
You might check out Empire, which is integration between JPA and SPARQL letting you build an application around standard POJOs which are stored in an RDF triplestore. It handles round-tripping between RDF and Java for you and abstracts most of the details of RDF -- though some SPARQL knowledge is ideal.
I am building an ontology-processing tool and need lots of examples of various owl ontologies, as people are building and using them in the real world. I'm not talking about foundational ontologies such as Cyc, I'm talking about smaller, domain-specific ones.
There's no definitive collection afaik, but these links all have useful collections of OWL and RDFS ontologies:
schemaweb.info
vocab.org
owlseek
linking open data constellation
RDF schema registry (rather old now)
In addition, there are some general-purpose RDF/RDFS/OWL search engines you may find helpful:
sindice
swoogle
Ian
My go-to site for this probably didn't exist at the time of the question. For latecomers like me:
Linked Open Vocabularies
I wish I'd found it much sooner!
It's well-groomed, maintained, has all the most-popular ontologies, and has a good search engine. However, it doesn't include some specialized collections, most notably, (most of?) the stuff in OBO Foundry.
Thanks! A couple more I found:
OntoSelect - browsable ontology repository
Protege Ontology Library
CO-ODE Ontologies
Within the life-science domain, the publically abvailable ontologies can be found listed on the OBO Foundry site. These ontologies can be queried via the ontology lookup service or the NCBO's Bioportal, which also contains additional resources.
One more concept search tool: falcons
There is also one good web engine for searching for ontologies. It is called Watson Semantic Web Search and you can try it here.