3. Queries Applied Artificial Intelligence Prof. Dr. Bernhard Humm Faculty of Computer Science Hochschule Darmstadt University of Applied Sciences

Transcription

1 3. Queries Applied Artificial Intelligence Prof. Dr. Bernhard Humm Faculty of Computer Science Hochschule Darmstadt University of Applied Sciences 1

2 Retrospective Knowledge Representation (1/2) What is the purpose of knowledge representation? Give examples for classes, individuals, relationships, and rules What is an ontology? Name different knowledge representation approaches What does reasoning mean? Give an example. How does it work? Explain open word assumption and closed world assumption. What are the differences? What are implications of the assumption made? (tbc ) 2

3 Retrospective Knowledge Representation (2/2) What is a resource in RDF? How are namespaces used? What is an RDF triple? How are classes declared in RDF(S)? How are individuals (instances) assigned to classes? What are differences between classes / instances in RDF(S) and in object-orientation? How are properties declared in RDF(S)? How are properties used? Name the Semantic Web principle. What are the implications? Which serialization syntaxes exist for RDF? 3

4 Agenda SPARQL Services / Products Map 4

5 SPARQL Query Language Query Language for RDF Standardized by W3C Current Version: 1.1 Specification: 5

6 Namespaces Namespace prefix definition (slightly different from RDF) Example: PREFIX dbpedia: < PREFIX yago: < PREFIX rdf: < PREFIX rdfs: < PREFIX dbpedia-owl: < PREFIX dbpprop: < PREFIX foaf: < PREFIX xsd: < 6

7 Simple SELECT query: What is Raphael s nationality? PREFIX dbpedia: < PREFIX Keywords dbpedia-owl: SELECT, < WHERE PREFIX dbpprop: < PREFIX simliar yago: to SQL < Variable prefixed by? SELECT?n WHERE { dbpedia:raphael dbpedia-owl:nationality?n. Result when executed in Protegé: dbpedia:italy 7

8 Find all Italian Artists SELECT?p WHERE {?p rdf:type dbpedia-owl:person ; dbpedia-owl:nationality dbpedia:italy. No Abbreviated Notation as in RDF 8

9 Multiple result variables: Artists with their nationality SELECT?p?n WHERE {?p rdf:type dbpedia-owl:person ; dbpedia-owl:nationality?n. No If all used Variables shall be returned then SELECT * may be used 9

10 SELECT DISTINCT: What nationalities do Artists have? SELECT DISTINCT?n WHERE {?p rdf:type dbpedia-owl:person ; dbpedia-owl:nationality?n. No Abbreviated Notation as in RDF 10

11 Path expressions: Paintings by Italian artists SELECT?a WHERE {?a rdf:type yago:painting ; dbpprop:artist/dbpedia-owl:nationality dbpedia:italy. No Path expression using /. Abbreviation for:?a dbpprop:artist?p.?p dbpedia-owl:nationality dbpedia:italy. 11

12 Transitive closures: Artists who were born in Spain No SELECT DISTINCT?p WHERE {?p dbpedia-owl:birthplace?l.?l dbpedia-owl:ispartof* dbpedia:spain. * : Zero to n predicates dbpedia-owl:ispartof, e.g. dbpedia:barcelona dbpedia-owl:ispartof dbpedia:catalonia. dbpedia:catalonia dbpedia-owl:ispartof dbpedia:spain. 12

13 More SPARQL concepts ASK queries: checks for a condition and returns a boolean result CONSTRUCT queries: generate new RDF statements like production rules FILTER: allows to formulate additional conditions, e.g., on datatypes OPTIONAL: specifies optional values EXISTS / NOT EXISTS: negation GROUP BY, HAVING: aggregation ORDER BY: sorting Subqueries 13

14 Construct paintings, sculptures, artists, museums, artistic movements (1/2) To be executed on Dbpedia SPARQL endpoint CONSTRUCT {?artwork rdf:type?type ; dbpprop:artist?artist ; rdfs:label?label ; dbpprop:year?year ; dbpedia-owl:abstract?abstract ; foaf:depiction?depiction ; dbpprop:museum?museum. PREFIX dbpedia: < PREFIX yago: < PREFIX rdf: < PREFIX rdfs: < PREFIX dbpedia-owl: < PREFIX dbpprop: < PREFIX foaf: < PREFIX dbp-res: < PREFIX xsd: < rdf:type dbpedia-owl:person ; rdfs:label?artistlabel ; dbpedia-owl:birthdate?birthdate ; dbpedia-owl:deathdate?deathdate ; dbpedia-owl:birthplace?birthplace ; dbpedia-owl:deathplace?deathplace ; dbpedia-owl:nationality?nationality ; dbpedia-owl:abstract?artistabstract ; dbpedia-owl:movement?movement ; dbpedia-owl:influencedby?influence ; foaf:depiction?artistdepiction.?movement rdf:type yago:artisticmovement ; rdfs:label?movementlabel ; dbpedia-owl:abstract?movementabstract.?museum rdf:type yago:museum ; rdfs:label?museumlabel ; dbpedia-owl:abstract?museumabstract ; dbpprop:website?museumwebsite ; foaf:depiction?museumdepiction ; dbpedia-owl:location?museumlocation ; dbpprop:latitude?lat ; dbpprop:longitude?long. WHERE... 14

15 Construct paintings, sculptures, artists, museums, artistic movements (2/2)... WHERE {?artwork rdf:type?type ; dbpprop:artist?artist ; rdfs:label?label ; dbpedia-owl:abstract?abstract ; foaf:depiction?depiction. FILTER (?type = yago:painting ?type = yago:sculpture ) FILTER ( lang(?label) = "en" ) FILTER ( lang(?abstract ) = "en" ) OPTIONAL {?artwork dbpprop:year?year. FILTER ( datatype(?year ) = xsd:integer )?artist rdf:type dbpedia-owl:person ; rdfs:label?artistlabel ; dbpedia-owl:abstract?artistabstract. FILTER ( lang(?artistlabel) = "en" ) FILTER ( lang(?artistabstract ) = "en" ) OPTIONAL {?artist dbpedia-owl:birthdate?birthdate. FILTER ( datatype(?birthdate ) = xsd:date ) OPTIONAL {?artist dbpedia-owl:deathdate?deathdate. FILTER ( datatype(?deathdate ) = xsd:date ) OPTIONAL {?artist dbpedia-owl:birthplace?birthplace.?birthplace rdf:type yago:location OPTIONAL {?artist dbpedia-owl:deathplace?deathplace.?deathplace rdf:type yago:location OPTIONAL {?artist dbpedia-owl:nationality?nationality.?nationality rdf:type yago:location OPTIONAL {?artist dbpedia-owl:influencedby?influence.?influence rdf:type dbpedia-owl:person. OPTIONAL {?artist foaf:depiction?artistdepiction OPTIONAL {?artist dbpedia-owl:movement?movement. as yago:artisticmovement ?movement rdfs:label?movementlabel ; dbpedia-owl:abstract?movementabstract. FILTER ( lang(?movementlabel ) = "en" ) FILTER ( lang(?movementabstract ) = "en" ) OPTIONAL {?artwork dbpprop:museum?museum.?museum rdf:type yago:museum ; rdfs:label?museumlabel ; dbpedia-owl:abstract?museumabstract. FILTER ( lang(?museumlabel ) = "en" ) FILTER ( lang(?museumabstract ) = "en" ) OPTIONAL {?museum dbpprop:website?museumwebsite. OPTIONAL {?museum foaf:depiction?museumdepiction. OPTIONAL {?museum dbpedia-owl:location?museumlocation.?museumlocation rdf:type yago:location OPTIONAL {?museum dbpprop:latitude?lat ; dbpprop:longitude?long. FILTER ( datatype(?lat) = xsd:double) FILTER ( datatype(?long) = xsd:double) 15

16 Construct location hierarchies for artists PREFIX dbpedia: < PREFIX yago: < PREFIX rdf: < PREFIX rdfs: < PREFIX dbpedia-owl: < PREFIX dbpprop: < PREFIX foaf: < PREFIX dbp-res: < PREFIX xsd: < CONSTRUCT {?location2 rdf:type yago:location ; rdfs:label?label ; dbpedia-owl:abstract?abstract ; geo:lat?lat ; geo:long?long.?location2 dbpedia-owl:ispartof?location3. WHERE { {?artwork rdf:type yago:painting UNION {?artwork rdf:type yago:sculpture {?artwork dbpprop:artist/(dbpedia-owl:birthplace dbpedia-owl:deathplace dbpedia-owl:nationality)?location. UNION {?artwork dbpprop:museum/dbpedia-owl:location?location.?location (dbpedia-owl:ispartof dbpedia-owl:city dbpedia-owl:country)*?location2.?location2 rdf:type yago:location ; rdfs:label?label. FILTER ( lang(?label ) = "en" ) OPTIONAL {?location2 dbpedia-owl:abstract?abstract ; geo:lat?lat ; geo:long?long. FILTER ( lang(?abstract ) = "en" ) OPTIONAL {?location2(dbpedia-owl:ispartof dbpedia-owl:city dbpedia-owl:country)?location3. 16

17 Construct ontology classes PREFIX yago: < PREFIX rdf: < PREFIX rdfs: < PREFIX dbpedia-owl: < PREFIX dbpprop: < PREFIX foaf: < PREFIX dbp-res: < PREFIX xsd: < CONSTRUCT {?c3 rdfs:subclassof?c4 ; rdf:type?t ; rdfs:label?l ; rdfs:comment?c. WHERE {?c1 rdfs:subclassof?c2. FILTER (?c1 = yago:painting ?c1 = yago:sculpture ?c1 = dbpedia-owl:person?c1 = yago:artisticmovement ?c1 = yago:museum ?c1 = yago:location )?c1 rdfs:subclassof*?c3.?c3 rdfs:subclassof?c4. OPTIONAL {?c3 rdf:type?t. OPTIONAL {?c3 rdfs:label?l. FILTER ( lang(?l ) = "en" ) OPTIONAL {?c3 rdfs:comment?c. FILTER ( lang(?c ) = "en" ) 17

18 Agenda SPARQL Services / Products Map 18

19 Services and product maps A services map depicts groups of functionality that products offer in a certain area like knowledge representation. Eamples: - Knowledge editor - Reasoning engine A product map maps the services to specific products (tools and tool suites; commercial and open source) Examples: - Protégé - Pellet 19

20 Method for selecting products in a project 1. Mark the services which are relevant in this project. 2. Retrieve products that cover the relevant services from the product map product candidates 3. Select a product or a set of products 1. Determine evaluation criteria, e.g., programming language, operating system, performance, price, etc. 2. Remove product candidates that fail on a criterion product short list (2-5 products) 3. Determine criteria for each candidate on the short list 4. Select candidate(s) with best fit. 4. If more than one product was chosen (best-of-breed approach) integrate the products for your solution. 20

21 Knowledge Editor Data Integration / Semantic Enrichment Knowledge Resources Knowledge Representation Services Map Product bundle for many knowledge representation services KB access via programming language Off-the-shelf ontologies Integrated Environment API Query Engine Reasoner Knowledge Base 21 Editing ontologies Storing ontologies Inferencing Integrating knowledge resources

22 Knowledge Editor Data Integration / Semantic Enrichment Knowledge Resources Knowledge Representation Product Map Topbraid Suite, OntoStudio, Virtuoso, GraphDB, AllegroGraph, Sesame, JENA, Integrated Environment API Query Engine Reasoner Knowledge Base 22 Protégé, Topbraid Composer, Pellet, FaCT++, HermiT,.. Dbpedia, YAGO, CYC, WikiData, GND,

23 Product Map as a table 23