jena

问题 I'm having trouble expressing the following situation in my Ontology: Suppose I have four people voting and four votes (so there is a one-to-one mapping between vote and voter). People can either vote yes or no. If I know the outcome of three people's votes, I ought to be able to deduce the fourth person's vote. So to reiterate: John, Bob, Mary, and Carol each vote. Since there are four people there are four votes. The outcome of the vote is a tie (2 yes, and 2 no). Later on the reasoner

问题 I am stuck in the middle of ontology creation. I want to create an OWL file using Java which is my objective. I have created the hierarchical clusters but now I have to use those clusters in ontology creation. Thanks in advance. I have tried this so far. I got Dickinson's point. Now this is my code and I am getting an Exception as Exception in thread "main" com.hp.hpl.jena.shared.BadURIException: Only well-formed absolute URIrefs can be included in RDF/XML output: Code: 57/REQUIRED_COMPONENT

问题 I am trying to create a SPARQL query that performs the logarithm function on the returned results. I have implemented the Jena SPARQL engine in my java program, but have only been able to find these available functions : http://jena.sourceforge.net/ARQ/library-function.html Does anybody know of a way to take the logarithm (preferably the natural log) of a SPARQL return variable? Example query that works: SELECT DISTINCT ((?Transactions_Num) AS ?BusinessValue) WHERE {{?BusinessProcess relation

问题 It is a follow up question to : How to list and count the different types of node and edge entities in the graph data using SPARQL query? So assuming I have the different node entities and edge entities of a given graph, how do I go about listing all triples, given a node-edge-node pattern? And how do I generate ALL node-edge-node patterns given the node and edge entities? Example: If there is a network consisting of papers(nodes), authors(nodes), conferences(nodes), iswrittenby(edge),

问题 I am trying to write propreties into a model and then query it.This part of mycode: String directory = "EMAILADDRESS" ; //create the dataset for the tdb store Dataset ds = TDBFactory.createDataset(directory) ; //create default rdf model ds.begin(ReadWrite.WRITE); Model model = ds.getDefaultModel() ; //write to the tdb dataset When I write this and then query the query shows no result ...but when I interchange the order of model and begin i.e. Model model = ds.getDefaultModel() ; //write to

问题 I am executing the SPARQL query below with Jena, where uriNode is a String representing a URI , but this query doesn't give me any results. I've already checked the database and this URI does exist there. What's the problem? String queryString2 = "PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> " + "PREFIX dc: <http://purl.org/dc/elements/1.1/> SELECT ?author WHERE { " + "?document dc:creator ?author." + "FILTER (?document = \"" + uriNode + "\" ). }"; 回答1: AndyS's answer is right,

问题 Hi I am new to the Semantic Web domain and Apache Jena enviroments too, which is why I am posting this question. I have a project that makes use of Jena API. And when I run it, it shows output in the console. I did run Fuseki server from cmd line and it ran as a local server and I could do some playing around with queries and all that. My question is, is it possible to run the project on the server through my project that makes use of the API, and if so, why it should be done? I am confused

问题 I'm using Jena and Sparql to query the ontology file. I have class Tag with two subclasses : C++ and Java. class Subject with several subclasses, which stand for particular University subjects: "C++ programming","System programming", "Java programming" etc. ObjectProperty "hasTags" domain:Subject range:Tag. Each class subject has some tag like "Java", "C++" When executing query SELECT ?subject WHERE { ?subject owl:equivalentClass ?restriction . ?restriction owl:onProperty ont:hasTags .

问题 If I have classes ABC and CDE defined as intersections of classes A,B,C,D,E as follows: <Class rdf:about="&blah;ABC"> <equivalentClass> <Class> <intersectionOf rdf:parseType="Collection"> <Restriction> <onProperty rdf:resource="&blah;hasMarker"/> <someValuesFrom rdf:resource="&blah;A"/> </Restriction> <Restriction> <onProperty rdf:resource="&blah;hasMarker"/> <someValuesFrom rdf:resource="&blah;B"/> </Restriction> <Restriction> <onProperty rdf:resource="&blah;hasMarker"/> <someValuesFrom rdf

问题 I am working on a project which need to save multiple ontologies in one TDB. I tried to do it in my own way, but it didn't work. Help me please..If you know how to use TDB , could you post the code applied to my code? String directory = "./111"; Dataset dataset = TDBFactory.createDataset(directory); Model tdb = dataset.getNamedModel("test1"); String source = "file:///e:/Course.rdf"; System.out.println(tdb.toString()); tdb.commit(); tdb.close(); String source2 = "file:///e:/lyx/resouces