Thank you! Can you suggest any texts that teach how to effectively write
inference rules for Jena? Also, I have made good progress on the Roster
example, but I'm stuck on the new node URI:
I'm successfully creating a new bNode from my rule now, but I'm having
trouble defining the node's URI.
When I use this rule:
[r1: (?x rdf:type ro:RosterEntry), (?x ro:hasSignature ?sig), regex(?sig,
> '(.*) (.*)', ?first, ?last), makeSkolem(?y, ?x) -> (?y ro:hasFirstName
> ?first), (?y ro:hasLastName ?last), (?y rdf:type ro:Person)]
Jena infers two new nodes like I was hoping for:
1PXx9jabIZ6w9mfO0GygJA== type Person .
> 1PXx9jabIZ6w9mfO0GygJA== hasLastName "Jones" .
> 1PXx9jabIZ6w9mfO0GygJA== hasFirstName "Sally" .
> lOqL7Rx2Lwv5OK6BWD/jSA== type Person .
> lOqL7Rx2Lwv5OK6BWD/jSA== hasLastName "Smith" .
> lOqL7Rx2Lwv5OK6BWD/jSA== hasFirstName "Bob" .
However, I'm not having success changing the node URIs. When I change the
rule to this:
[r1: (?x rdf:type ro:RosterEntry), (?x ro:hasSignature ?sig), regex(?sig,
> '(.*) (.*)', ?first, ?last), makeSkolem(?y, ?x), uriConcat('
> http://example.com/ont/roster/people/', ?first, ?last, ?y) -> (?y
> ro:hasFirstName ?first), (?y ro:hasLastName ?last), (?y rdf:type
> ro:Person)]
Jena doesn't seem to infer any new nodes.
I tried separating it into another rule:
[r1: (?x rdf:type ro:RosterEntry), (?x ro:hasSignature ?sig), regex(?sig,
> '(.*) (.*)', ?first, ?last), makeSkolem(?y, ?x) -> (?y ro:hasFirstName
> ?first), (?y ro:hasLastName ?last), (?y rdf:type ro:Person)]
> [r2: (?x rdf:type ro:Person), (?x ro:hasFirstName ?first), (?x
> ro:hasLastName ?last), uriConcat('http://example.com/ont/roster/people/',
> ?first, ?last, ?y) -> print('woot', ?y)]
What is strange is that with the second rule, the inference engine prints
out:
'woot' <http://example.com/ont/roster/people/BobSmith>
'woot' <http://example.com/ont/roster/people/SallyJones>
But, when I listStatements and print out the InfModel,
I get the same node URIs:
1PXx9jabIZ6w9mfO0GygJA== type Person .
> 1PXx9jabIZ6w9mfO0GygJA== hasLastName "Jones" .
> 1PXx9jabIZ6w9mfO0GygJA== hasFirstName "Sally" .
> lOqL7Rx2Lwv5OK6BWD/jSA== type Person .
> lOqL7Rx2Lwv5OK6BWD/jSA== hasLastName "Smith" .
> lOqL7Rx2Lwv5OK6BWD/jSA== hasFirstName "Bob" .
So, does uriConcat not set the node's uri permanently?
On Sun, May 24, 2020 at 6:03 AM Dave Reynolds <[email protected]>
wrote:
> Sorry, only just noticed this question. Responses below:
>
> On 20/05/2020 10:41, Kenneth Keefe wrote:
> > Thanks for all the help so far! I've made some good progress on this
> > example I'm trying to forge. Here are the files for this example:
> >
> > Ontology: https://cioi.iti.illinois.edu/ont/examples/roster.owl
> > Rules: https://cioi.iti.illinois.edu/ont/examples/roster.rules
> >
> > Using this code:
> >
> > OntModel model =
> ModelFactory.*createOntologyModel*(OntModelSpec.*OWL_MEM*);
> >
> > model.read("file:roster.owl");
> >
> > List<Rule> rules = Rule.*rulesFromURL*("file:roster.rules");
> >
> > Reasoner reasoner = new GenericRuleReasoner(rules);
> >
> > InfModel inf = ModelFactory.*createInfModel*(reasoner, model);
> >
> >
> > printAllStatements(inf);
> >
> > I get this output (I use the LocalName for the predicates and objects for
> > readability):
> >
> > b04230c7-55dc-4e08-92d7-26559c0c478f hasLastName "Smith" .
> > c33de24f-82f1-4aa2-a78e-73201341b274 type Person .
> > c812ff54-30bf-49e7-8e35-3544dad096b7 hasFirstName "Sally" .
> > 16b7a887-2fb9-4bdb-a529-34ca8b3137e4 hasFirstName "Bob" .
> > b31eb7d5-a8ad-469e-ae83-366bdf46fd72 hasLastName "Jones" .
> > 8b46f0c7-4eb2-41e2-8789-8967e8f63eec type Person .
> > http://example.com/ont/roster/ versionIRI .
> > http://example.com/ont/roster/ type Ontology .
> > http://example.com/ont/roster/RosterEntry type Class .
> > http://example.com/ont/roster/bobEntry hasSignature "Bob Smith" .
> > http://example.com/ont/roster/bobEntry type RosterEntry .
> > http://example.com/ont/roster/bobEntry type NamedIndividual .
> > http://example.com/ont/roster/Person type Class .
> > http://example.com/ont/roster/hasLastName range string .
> > http://example.com/ont/roster/hasLastName domain Person .
> > http://example.com/ont/roster/hasLastName type DatatypeProperty .
> > http://example.com/ont/roster/sallyEntry hasSignature "Sally Jones" .
> > http://example.com/ont/roster/sallyEntry type RosterEntry .
> > http://example.com/ont/roster/sallyEntry type NamedIndividual .
> > http://example.com/ont/roster/hasSignature range string .
> > http://example.com/ont/roster/hasSignature domain RosterEntry .
> > http://example.com/ont/roster/hasSignature type DatatypeProperty .
> > http://example.com/ont/roster/hasFirstName range string .
> > http://example.com/ont/roster/hasFirstName domain Person .
> > http://example.com/ont/roster/hasFirstName type DatatypeProperty .
> >
> > Here are my questions:
> >
> > Focusing on just the Bob Smith entry:
> >
> > b04230c7-55dc-4e08-92d7-26559c0c478f hasLastName "Smith" .
> > c33de24f-82f1-4aa2-a78e-73201341b274 type Person .
> > 16b7a887-2fb9-4bdb-a529-34ca8b3137e4 hasFirstName "Bob" .
> >
> > 1. Are these unique ids of anonymous nodes?
>
> Yes.
>
> > 2. Why are they not identical across these three lines?
>
> Because your ?y variable hasn't been bound in the rule body, each triple
> pattern finds there's no value for ?y and separately treats it as a bNode.
>
> If you want a shared bNode then use makeTemp(?y) in the body (or
> makeSoklem).
>
> > 3. Is there a way to name these new nodes in the rule? For example, make
> > the new node http://example.com/ont/roster/people/BobSmith.
>
> Sure, use uriConcat, something like (untested):
>
> uriConcat('http://example.com/ont/roster/people/', ?first, ?last,
> ?y) -> ...
>
> Dave
>
> >
> > Thank you!
> >
> > Ken
> >
> >
> >
> >
> >
> > On Tue, May 12, 2020 at 1:44 AM Lorenz Buehmann <
> > [email protected]> wrote:
> >
> >> Hi,
> >>
> >> I think the rule would be basically
> >>
> >> [r1: (?x rdf:type ex:RosterEntry), (?x ex:hasSignature ?sig),
> >> regex(?sig, '(.*) (.*)', ?first, ?last) -> (?x ex:hasFirstName
> >> ?first), (?x ex:hasLastName ?last), (?x rdf:type ex:Person) ) ]
> >>
> >> Note, it's untested and you have to define your prefix ex: in the rules
> >> file. You might also have to adapt the regex pattern to cover different
> >> white space chars.
> >>
> >> On 12.05.20 00:56, Kenneth Keefe wrote:
> >>> I am pretty new to using Jena and OWL. I have read many great tutorials
> >>> regarding RDF and OWL. The focus of those tutorials has largely been
> how
> >> to
> >>> structure the ontology and define restrictions on properties and such.
> >>> However, I have not been able to find good tutorials that explain how
> >>> inference is done and how I can define my own inference rules. I'm
> >>> wondering if I am simply not searching for the right thing.
> >>>
> >>> Regardless, here is a significant example that I think will really help
> >> me
> >>> get started with inference using Jena. I created a minimal example to
> >>> enable discussion. Here is a pastebin: https://pastebin.com/ScTGcbcZ
> >>>
> >>> The ontology has two classes, RosterEntry and Person and three data
> >>> properties, Signature (associated with RosterEntry), and FirstName and
> >>> LastName (both associated with Person). The example also has two
> >>> RosterEntry individuals with signatures of "Bob Smith" and "Sally
> Jones."
> >>>
> >>> I would like to write a rule that causes Jena to infer the following
> new
> >>> facts:
> >>>
> >>> <owl:Individual>
> >>>> <rdf:type
> >>>> rdf:resource="http://example.com/ont/roster/Person"; />
> >>>> <hasFirstName>Bob</hasFirstName>
> >>> <hasLastName>Smith</hasLastName>
> >>>
> >>> </owl:Individual>
> >>>
> >>>
> >>> <owl:Individual>
> >>>> <rdf:type
> >>>> rdf:resource="http://example.com/ont/roster/Person"; />
> >>>> <hasFirstName>Sally</hasFirstName>
> >>> <hasLastName>Jones</hasLastName>
> >>>
> >>> </owl:Individual>
> >>>
> >>>
> >>> How do I do that? Full answers or nudges in the right direction are
> both
> >>> very welcome. Thank you!
> >>>
> >>> Ken
> >>>
> >>
> >>
> >
>
--
-------
Ken Keefe
Senior Software Engineer
Information Trust Institute
University of Illinois at Urbana-Champaign
1308 W. Main St.
CSL 225
Urbana, Illinois 61801, USA
Phone: 217-244-3203
Web: https://www.perform.illinois.edu/~kjkeefe
Email: [email protected]
