semantic web assignment 2

Semantic Web Assignment 2 Studentname: Barry Kollee Student number: 10349863 Student username: UvA student ([email protected]) Assignment name: WebKR Assignment 2

Developing an OWL ontology with Protege

1. Chose the domain of your ontology

My domain is ‘Apple devices specifications’. 2. Define two classes using restrictions as shown in lecture 3

• iPhone capacities (device is available in only 16, 32 and 64 gb.) o {16gb, 32gB, 64gB}

• iPod colors(device has only the colors red, blue, pink, green, gray, black) o {red, blue, pink, green, gray, black}

3. Imagine at least 3 instances of these classes. For each instance, write a triple in which you assign a value to one of the preoperties used in the restrictions above. (i.e subject = the instance, predicate = the property used in the restriction object = the value that you chose)

• The property for the iPod is hasColors. • The property for the iPhone is hasCapacity.

4. Load your ontology into Protege. My code written with turtle syntax: @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . @prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> . @prefix owl: <http://www.w3.org/2002/07/owl#> . @prefix xsd: <http://www.w3.org/2001/XMLSchema#> . @prefix ex: <http://www.example.org/> . :iPhone rdf:type owl:Class ;

rdfs:label "iPhone" ; rdfs:subClassOf :Specifications , [ rdf:type owl:Restriction ; owl:onProperty ex:hasCapacity ; owl:allValuesFrom ex:Capacity ; ] ; owl:disjointWith ex:Capacity. :iPod rdf:type owl:Class ; rdfs:label "iPod" ; rdfs:subClassOf :Specifications , [ rdf:type owl:Restriction ; owl:onProperty ex:hasColors ; owl:allValuesFrom ex:Colors . ] ; owl:disjointWith ex:Colors . ex:16gB rdf:type ex:Capacity . ex:32gB rdf:type ex:Capacity . ex:64gB rdf:type ex:Capacity . ex:red rdf:type ex:Colors . ex:blue rdf:type ex:Colors . ex:pink rdf:type ex:Colors . ex:green rdf:type ex:Colors . ex:gray rdf:type ex:Colors . ex:black rdf:type ex:Colors .

5. Show that Protege classifes your instances correctly.

Output of the Class Hierarchy (OntoGraf) with Protégé 4.1

6. Explain which type of restriction you used. owl:someValuesFrom, owl:allValuesFrom, owl:hasValue, owl:cardinality I’ve used owl: allValuesFrom for both of my classes. You would be unable to predict if an iPhone has a specific capacity or not. For that reason I’ve chosen for owl:allValuesFrom which results in all the possible results; in this case the iPhone capacities. On the other hand we have the iPod hasColors: property. The reason for choosing owl:allValuesFrom is equal as my explanation for choosing it with the iPhone. You would be unable to predict if iPod’s have one Color or more. With owl:allValuesFrom we cover the whole list. 7. Did you use necessary or necessary and sufficient conditions? I used sufficient conditions, because you can’t be sure what kind of Colors of Capacities you will find under Capacity and Colors.

SPARQL

Perform 3 queries on http://www.dbpedia.org. You can use one of their web interfaces to perform the queries either http://dbpedia.org/snorql/ or http://dbpedia.org/sparql . Alternatively, you can use ARQ. Hand in the 3 queries along with the results for each query. You should show examples of both schema queries and regular queries. Identify, which queries are schema queries and which ones are regular. Try at least one query that is not a select query (e.g a construct or ask query).

First Query: Select Query for the Semantic_Web (abstract) SELECT ?abstract WHERE { { <http://dbpedia.org/resource/Semantic_Web> <http://dbpedia.org/ontology/abstract> ?abstract } } Gives me several results (all kinds of languages). The English one gives: "The Semantic Web is a collaborative movement led by the World Wide Web Consortium (W3C) that promotes common formats for data on the World Wide Web. By encouraging the inclusion of semantic content in web pages, the Semantic Web aims at converting the current web of unstructured documents into a "web of data". It builds on the W3C's Resource Description Framework (RDF). According to the W3C, "The Semantic Web provides a common framework that allows data to be shared and reused across application, enterprise, and community boundaries. " The term was coined by Tim Berners-‐Lee, the inventor of the World Wide Web and director of the World Wide Web Consortium, which oversees the development of proposed Semantic Web standards. He defines the Semantic Web as "a web of data that can be processed directly and indirectly by machines. " While its critics have questioned its feasibility, proponents argue that applications in industry, biology and human sciences research have already proven the validity of the original concept. Scholars have explored the social potential of the semantic web in the business and health sectors, and for social networking. The original 2001 Scientific American article by Berners-‐Lee described an expected evolution of the existing Web to a Semantic Web, but this has yet to happen. In 2006, Berners-‐Lee and colleagues stated that: "This simple idea... remains largely unrealized.""@en1 Second Query: Select Query for Concepts of DBPedia (with a limit of 5 results)2 SELECT DISTINCT ?Concept where {?s a ?Concept} LIMIT 5 This Query gives me this result: Third Query: Comparing the height of the Eiffel Tower to the Rocky Mountains PREFIX prop: <http://dbpedia.org/property/> ASK { <http://dbpedia.org/resource/Eiffel_Tower> prop:height ?eiffel . <http://dbpedia.org/resource/Rocky_Mountains> prop:height ?rocky . FILTER(?eiffel > ?rocky) . } Gives me the result true.

1 http://dbpedia.org/sparql?default-‐graph-‐uri=http%3A%2F%2Fdbpedia.org&query=SELECT+%3Fabstract%0D%0AWHERE+{%0D%0A{+%3Chttp%3A%2F%2Fdbpedia.org%2Fresource%2FSemantic_Web%3E+%3Chttp%3A%2F%2Fdbpedia.org%2Fontology%2Fabstract%3E+%3Fabstract+}%0D%0A}%0D%0A&format=text%2Fhtml&timeout=0&debug=on; result of Quering http://dbpedia.org/resource/Semantic_Web 2 http://www.cambridgesemantics.com/semantic-‐university/sparql-‐by-‐example

PREFIX prop: <http://dbpedia.org/property/> ASK { <http://dbpedia.org/resource/Eiffel_Tower> prop:height ?eiffel . <http://dbpedia.org/resource/Rocky_Mountains> prop:height ?rocky . FILTER(?eiffel < ?rocky) . } Gives me the result false. The reults which I retrieved from the Select query of the concepts gave me a schema because I used a metaclass which identifies my query as a schema query.3

Joseki Set up Joseki (http://www.joseki.org/) You'll _nd instructions on black-‐ board. Load your ontology into Joseki. Write one sparql sparql query that you can run over your ontology. Show the results of running those queries against your ontology. Unfortunately I was unable to get Joseki running on my Mac. It could be because of compatibility issues. (I’ve got mountain Lyon installed). However I did some research on a possible query for querying the iPod color. Which I could not test unfortunately.4 PREFIX : <http://www.w3.org/2011/12/appledevicespecifications.owl#> PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> SELECT ?color FROM <http://www.w3.org/2011/12/appledevicespecifications.owl> WHERE { ?iPod rdf:type/rdfs:subClassOf* color:Colors . }

3 http://msdn.microsoft.com/en-‐us/library/windows/desktop/aa393278%28v=vs.85%29.aspx 4 http://www.cambridgesemantics.com/semantic-‐university/sparql-‐by-‐example

semantic web assignment 2

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