Semantic Web                                               Technologies                                                   ...
Semantic Web Technologies    Content2    1. Introduction    2. Semantic Web - Basic Architecture             Languages of ...
2. Semantic Web - Basic Architecture             Languages of the Semantic Web - Part 13             Semantic Web Technolo...
Semantic Web Technologies    Content4    2. Semantic Web Basic Architecture       The Languages of the Semantic Web - Part...
What is this?5             Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienst...
What`s the difference?6             Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Pots...
Semiotic Triangle7                                                             shared concept                             ...
The Designator in the Web8     Uniform                                                                                    ...
Uniform Resource Identifier9        ■ A Uniform Resource Identifier (URI) defines a simple and extensible schema          fo...
URI, Resource and                                                                                                     Reso...
Representation and     Presentation11     Metadata:      Content-type: text/html     Data:                                ...
HTTP Request / Response12                                                                                                 ...
HTTP Request / Response13                                                   Browser sends HTTP Request                    ...
Designator and Designatum                                                                                  Designatum14   ...
2. Semantic Web Basisarchitektur     2.1 Uniform Resource Identifier - URI15       Bezeichner und Bezeichnetes             ...
16             Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Okto...
Designator and Designatum17                   The distinguishing characteristic of [information] resources                ...
18                                               Metadata             Semantic Web Technologies , Dr. Harald Sack, Hasso-P...
Metadata19                   • „Metadata are data that contain information about other                       data“ and „Me...
URI, Ressource and     Metadata20                       URI                           http://www.tour-eiffel.fr/index.html...
Uniform Resource Identifier21     ■ URI combines      Address             □ Address (Locator)                      □ Unifor...
URI - Generic Syntax22        ■ US-ASCII Encoding        ■ Percent Encoding for reserved characters, or characters that do...
URI - Generic Syntax23              URI = schema"://"[userinfo"@"]host[:port][path]["?"query]["#"fragment]         ■ schem...
URI - Generic Syntax24             Media Fragment Identifier                ■ Multimedia Data cover temporal and spatial di...
URIs im Semantic Web25       ■ What if a URI for a resource does not exist?       ■ Define a URI by yourself:              ...
Semantic Web Technologies     Content26     2. Semantic Web Basic Architecture        The Languages of the Semantic Web - ...
2. Semantic Web Basic Architecture             The Languages of the Semantic Web - Part 127             Semantic Web Techn...
Semantic Web Technologies     Content28     2. Semantic Web Basic Architecture        The Languages of the Semantic Web - ...
To a computer, then, the web is a flat, boring world devoid                                          of meaning. This is a...
Knowledge Representation ... a simple example        ■ How do I represent:          „Harald Sack has the phone number ++49...
Knowledge Representation ... a simple example        ■ How do I represent:          „Harald Sack has the phone number ++49...
Knowledge Representation ... a simple example        ■ How do I represent:          „Harald Sack has the phone number ++49...
Knowledge Representation and Communication                                                                           Conce...
Knowledge Representation and Communication         ■ Problem: 	                  new communication partners will not under...
Knowledge Representation and Communication           ■ Schemata have to be translated                                     ...
Knowledge Representation and Communication           ■ Schemata have to be translated           ■ Problems:              □...
Knowledge Representation and Communication         Level 3                                                                ...
38                                                                             D F                                        ...
Resource39                                             Description                                             Framework  ...
Resource40                                             Description                                             Framework  ...
Resource41                                             Description                                             Framework  ...
Resource42                                             Description                                             Framework  ...
Resource43                                             Description                                             Framework  ...
Resource44                                             Description                                             Framework  ...
Resource45                                             Description                                             Framework  ...
Resource46                                             Description                                             Framework  ...
Resource47                                             Description                                             Framework  ...
Resource48                                             Description                                             Framework  ...
Resource49                                             Description                                             Framework  ...
Resource50                                             Description                                             Framework  ...
Resource51                                             Description                                             Framework  ...
Resource52                                             Description                                             Framework  ...
Resource53                                             Description                                             Framework  ...
Resource54                                             Description                                             Framework  ...
Resource55                                             Description                                             Framework  ...
Resource                                    Description                                    Framework56          RDF Repres...
Resource                                Description                                Framework57                            ...
Resource                                Description                                Framework58                            ...
Resource                                Description                                Framework59                            ...
Resource                                Description                                Framework60                            ...
Resource                                Description                                Framework61                            ...
Resource                                Description                                Framework62                            ...
Resource                                Description                                Framework63                            ...
Resource                                Description                                Framework64                            ...
Resource                                Description                                Framework65                            ...
Resource                                Description                                Framework66             Multi Valued Re...
Resource                                Description                                Framework67        Multi Valued Relatio...
Resource                                  Description                                  Framework68             Blank Nodes...
Resource                                Description                                Framework69     Anonymous Blank Nodes  ...
Resource                                Description                                Framework70     Anonymous Blank Nodes  ...
Resource                                Description                                Framework71     Dereferencable Blank No...
Resource                                Description                                Framework72     Dereferencable Blank No...
Resource                                Description                                Framework73              Lists         ...
Resource                                    Description                                    Framework74              RDF Co...
Resource                                Description                                Framework75              RDF Container ...
Resource                                Description                                Framework76          RDF-Container     ...
Resource                                Description                                Framework77              RDF Container ...
Resource                                         Description                                         Framework78          ...
Resource                              Description                              Framework79        RDF-Collection          ...
Resource                              Description                              Framework80        RDF-Collection          ...
Resource                               Description                               Framework81        RDF-Collection        ...
What can we model with RDF?82             Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universitä...
Resource                                Description                                Framework83                            ...
Resource                                Description                                Framework84             RDF-Reification ...
Resource                                Description                                Framework85           RDF-Reification   ...
Resource                                Description                                Framework86         RDF-Reification     ...
Resource                                 Description                                 Framework87             RDF-Reificatio...
Resource                                 Description                                 Framework88             RDF-Reificatio...
Resource                                Description                                Framework89          RDF-Reification    ...
RDF and Data Integration90             Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität P...
RDF and Data Integration91            • Simple Example: Bibliography Database                                      ID     ...
RDF and Data Integration92                   •       Database export into a set of relations                              ...
RDF and Data Integration93                       Harald Sack                 u:name                                       ...
RDF and Data Integration94                       Harald Sack                 u:name                                       ...
RDF and Data Integration95                                       Harald Sack           a:publishername                 Spr...
RDF - a Resume96                  RDF Model -- Summary                  • An RDF Model is a set of RDF statements         ...
Semantic Web Technologies     Content97     2. Semantic Web Basic Architecture        The Languages of the Semantic Web - ...
S  Next lecture98           D                                    F         R                                              ...
2. Semantic Web Basic Architecture     2.1 Uniform Resource Identifier     2.2 XML und XMLSchema     2.3 Resource Descripti...
2. Semantic Web Basic Architecture      2.1 Uniform Resource Identifier      2.2 XML und XMLSchema      2.3 Resource Descri...
2. Semantic Web Basic Architecture      2.1 Uniform Resource Identifier      2.2 XML und XMLSchema      2.3 Resource Descri...
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02 - Semantic Web Technologien - URI and RDF

  1. 1. Semantic Web Technologies Lecture Dr. Harald Sack Hasso-Plattner-Institut für IT Systems Engineering University of Potsdam Winter Semester 2012/13 Lecture Blog: http://semweb2013.blogspot.com/ This file is licensed under the Creative Commons Attribution-NonCommercial 3.0 (CC BY-NC 3.0)Dienstag, 23. Oktober 12
  2. 2. Semantic Web Technologies Content2 1. Introduction 2. Semantic Web - Basic Architecture Languages of the Semantic Web - Part 1 3. Knowledge Representation and Logics Languages of the Semantic Web - Part 2 4. Applications in the ,Web of Data‘ Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  3. 3. 2. Semantic Web - Basic Architecture Languages of the Semantic Web - Part 13 Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  4. 4. Semantic Web Technologies Content4 2. Semantic Web Basic Architecture The Languages of the Semantic Web - Part 1 • Uniform Resource Identifier - URI • Recapitulation: XML and XMLSchema • Resource Description Framework - RDF • RDF Schema • How Do We Get Semantics into WWW? • µFormats, schema.org, RDFa and GRDDL • Query Language SPARQL • Why RDF(S) is not enough Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  5. 5. What is this?5 Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  6. 6. What`s the difference?6 Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  7. 7. Semiotic Triangle7 shared concept Concept symbolizes refers to Symbol Object stands for „apple“ Ogden, Richards, Semiotic Triangle, 1923 Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  8. 8. The Designator in the Web8 Uniform □ different types of resource identifiers all constructed according to a uniform schema Resource □ whatever may be identified via URI Identifier □ to distinguish one resource from another Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  9. 9. Uniform Resource Identifier9 ■ A Uniform Resource Identifier (URI) defines a simple and extensible schema for worldwide unique identification of abstract or physical resources (RFC 3986). ■ Resource can be every object with a clear identity (according to the context of the application) □ as e.g., web pages, books, locations, persons, relations among objects, abstract concepts, etc. ■ The concept of URI is already established in various domains, as e.g., □ the Web (URL, PRN, pURL), □ Books and publications (ISBN, ISSN), □ Digital Object Identifier (DOI) Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  10. 10. URI, Resource and Resource Representation10 URI http://www.tour-eiffel.fr/index.html identifies representation represents (stands for) Metadata: Content-type: text/html Data: <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <title>Le site officiel de la Tour Eiffel</title> ... </html> Eiffel Tower Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  11. 11. Representation and Presentation11 Metadata: Content-type: text/html Data: defines <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> Presentation <head> <title>Le site officiel de la Tour Eiffel</title> ... </html> Representation Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  12. 12. HTTP Request / Response12 Browser sends HTTP Request GET http://www.tour-eiffel.fr/index.html HTTP/1.1 Host: www.tour-eiffel.fr Accept: text/htmlUser clicks Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  13. 13. HTTP Request / Response13 Browser sends HTTP Request Web Server processes request GET http://www.tour-eiffel.fr/index.html HTTP/1.1 Host: www.tour-eiffel.fr Accept: text/html Browser interprets representation and displays presentation Web Server sends HTTP Response HTTP/1.1 200 OK Content-Length: 3134 Web Server of Content-Type: text/html; charset=utf-8 www.tour-eiffel.fr <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <title>Le site officiel de la Tour Eiffel</title> ... </html> Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  14. 14. Designator and Designatum Designatum14 Designator ≠ The web page describes (designates) the Eiffel Tower The Eiffel Tower is described (designated) by the web page Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  15. 15. 2. Semantic Web Basisarchitektur 2.1 Uniform Resource Identifier - URI15 Bezeichner und Bezeichnetes René Magritte: Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam La trahison des images (1928)Dienstag, 23. Oktober 12
  16. 16. 16 Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  17. 17. Designator and Designatum17 The distinguishing characteristic of [information] resources is that all of their essential characteristics can be conveyed in a message. W3C: Architecture of the World Wide Web, Volume One □ A resource can be described (designated) via Metadata □ Even if the resource itself cannot be delivered from the web server, probably its representation might be available that describes the resource sufficiently. Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  18. 18. 18 Metadata Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  19. 19. Metadata19 • „Metadata are data that contain information about other data“ and „Metadata are required to fulfill a specific purpose or to achieve a specific result“ (informal definition, Wikipedia) • „Metadata are structures, encoded data that describe the characteristics of information bearing entities for the Metadaten purpose of identification, retrieval, evaluation and administration of the described entities.“ (W. R. Durrell: Data Administration: A practical Guide to Data Administration. McGraw – Hill, 1985) • „Metadata is machine understandable information about web resources or other things“ (Tim Berners-Lee: Axioms of Web Architecture: Metadata, 1997) Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  20. 20. URI, Ressource and Metadata20 URI http://www.tour-eiffel.fr/index.html identifies Resource: Eiffel Tower Representation describes (designates) Metadata: Content-type: text/html Data: <!DOCTYPE HTML PUBLIC "-//W3C//DTD represents HTML 4.01 Transitional//EN" Information about Resource: "http://www.w3.org/TR/html4/loose.dtd"> the Eiffel Tower Eiffel Tower <html> (stands for) <head> Metadata <title>Le site officiel de la Tour Eiffel</title> ... </html> Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  21. 21. Uniform Resource Identifier21 ■ URI combines Address □ Address (Locator) □ Uniform Resource Locator (URL, RFC 1738) □ denotes, where a resource can be found in the Web by stating its primary access mechanism □ might change during life cycle □ Identity (Name) Name □ Uniform Resource Name (URN, RFC 2141) □ persistent identifier for a Web resource □ remains unchanged during life cycle Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  22. 22. URI - Generic Syntax22 ■ US-ASCII Encoding ■ Percent Encoding for reserved characters, or characters that do not exist in US-ASCII encoding existieren pct-encoded = "%" HEXDIG HEXDIG ■ Reserved characters with special function reserved = gen-delims / sub-delims gen-delims = ":" / "/" / "?" / "#" / "[" / "]" / "@“ sub-delims = "!" / "$" / "&" / "" / "(" / ")" / "*" / "+" / "," / ";" / "=" ■ Permitted characters unreserved = ALPHA / DIGIT / "-" / "." / "_" / "~" ■ Extension to Universal Character Code (Unicode/ISO 10646) □ Internationalized Resource Identifier (IRI, RFC 3987) e.g.: Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  23. 23. URI - Generic Syntax23 URI = schema"://"[userinfo"@"]host[:port][path]["?"query]["#"fragment] ■ schema: e.g. http, ftp, mailto,... ■ userinfo: e.g. username:password ■ host: e.g. Domain-Name, IPv4/IPv6 Address ■ port: e.g. :80 for standard http port ■ path: e.g. path in file system of WWW server ■ query: e.g. parameters to be passed over to applications ■ fragment: e.g. determines a specific fragment of a document Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  24. 24. URI - Generic Syntax24 Media Fragment Identifier ■ Multimedia Data cover temporal and spatial dimension ■ pinpoint acces to multimedia resources via URI Media Fragment Identifier (W3C Media Fragments URI 1.0, 25. September 2012, W3C Recommendation) ■ Example: http://www.example.com/example.ogg#track=‘audio‘ http://www.example.com/example.ogg#track=‘audio‘&t=10s,20s http://www.example.com/example.ogg#track=‘video‘&xywh=160,120,320,240 ■ WWW Client and WWW Server have to take care for handling media fragments correctly, i.e. consequences for http protocol Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  25. 25. URIs im Semantic Web25 ■ What if a URI for a resource does not exist? ■ Define a URI by yourself: □ avoid overlaps  use your own website □ enables documentation at the same place ( Content Negotiation) ■ Separate URI for resource (Designatum) and its documentation (Designator) via URI references (i.e. via "#" fragments) or Content Negotiation z.B.: http://hpi.uni-potsdam.de/harald_foaf.rdf#me Sauermann, Cyganiak: Cool URIs for the Semantic Web, W3C Interest Group Note 03 December 2008, http://www.w3.org/TR/cooluris/ Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  26. 26. Semantic Web Technologies Content26 2. Semantic Web Basic Architecture The Languages of the Semantic Web - Part 1 • Uniform Resource Identifier - URI • Recapitulation: XML and XMLSchema • Resource Description Framework - RDF • RDF Schema • How Do We Get Semantics into WWW? • µFormats, schema.org, RDFa and GRDDL • Query Language SPARQL • Why RDF(S) is not enough Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  27. 27. 2. Semantic Web Basic Architecture The Languages of the Semantic Web - Part 127 Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  28. 28. Semantic Web Technologies Content28 2. Semantic Web Basic Architecture The Languages of the Semantic Web - Part 1 • Uniform Resource Identifier - URI • Recapitulation: XML and XMLSchema • Resource Description Framework - RDF • RDF Schema • How Do We Get Semantics into WWW? • µFormats, schema.org, RDFa and GRDDL • Query Language SPARQL • Why RDF(S) is not enough Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  29. 29. To a computer, then, the web is a flat, boring world devoid of meaning. This is a pity, as in fact documents on the web describe real objects and imaginary concepts, and give particular relationships between them. For example, a document might describe a person. The title document to a house describes a house and also the ownership relation with a person. [...] Tim Berners-Lee: W3 future directions, Plenary at 1st WWW Conference, 1994, Geneva (Switzerland) Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  30. 30. Knowledge Representation ... a simple example ■ How do I represent: „Harald Sack has the phone number ++49 (331) 5509-527“ <phonenr> <owner>Harald Sack</owner> <number>++49 (331) 5509-527</number> </phonenr> <person name=“Harald Sack“> <phonenr>49 (331) 5509-527</phonenr> </person> <person name=“Harald Sack“ phone=“49 (331) 5509-527“ /> is there a unique (intuitive) way to model knowledge? Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  31. 31. Knowledge Representation ... a simple example ■ How do I represent: „Harald Sack has the phone number ++49 (331) 5509-527“ Harald Sack has the phone number ++49 (331) 5509-527 Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  32. 32. Knowledge Representation ... a simple example ■ How do I represent: „Harald Sack has the phone number ++49 (331) 5509-527“ ■ Intuitive knowledge representation with directed graphs Harald Sack ++49 (331) 5509-527 has phone number Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  33. 33. Knowledge Representation and Communication Conceptual Domain Model Objects and Relations is translated into <xsd:schema xmlns:xsd="http://..."> <xsd:annotation> Schema A </xsd:... </xsd:schema> XML Schema Deployment XML- XML-based communication Parser via schema A Sender Receiver uses schema A uses schema A Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  34. 34. Knowledge Representation and Communication ■ Problem: new communication partners will not understand new communication partner new communication uses Schema B partner uses Schema C ??? ??? ??? XML- XML-based communication Parser via schema A Sender Receiver uses schema A uses schema A Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  35. 35. Knowledge Representation and Communication ■ Schemata have to be translated Schema A Schema B Reengineering of <xsd:schema xmlns:xsd="http://..."> <xsd:annotation> A-Schema <xsd:schema xmlns:xsd="http://..."> <xsd:annotation> B-Schema conceptual model </xsd:... </xsd:... </xsd:schema> </xsd:schema> Matching XML Document Translation Generation (XSLT) <xsl:stylesheet version="1.0” <xsl:stylesheet version="1.0” xmlns:xsl="http://....Transform" xmlns:xsl="http://....Transform" XML Document <xsl:template match="/"> <xsl:template match="/"> .... .... Translation </xsl:template> </xsl:template> Schemata A <-> B </xsl:stylesheet> </xsl:stylesheet> Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  36. 36. Knowledge Representation and Communication ■ Schemata have to be translated ■ Problems: □ Reengineering is expensive and complicated □ Reengineering would not be necessary with a conceptual knowledge representation languagh □ Schema translations (XSLT) are expensive and not necessary use abstract level above XML Resource Description Framework (RDF) • simple and extensible Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  37. 37. Knowledge Representation and Communication Level 3 OWL (abgeschlossene Welten) RDF RDFSchema Level 2 (Wissen über XML Objekte) XMLSchema Level 1 (Objekte) Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  38. 38. 38 D F R Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  39. 39. Resource39 Description Framework Resource ■ can be everything (in principle)... ■ must be uniquely identified and be referencable ■ ...simply via URI Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  40. 40. Resource40 Description Framework Description ■ = Descriptions of resources ■ ...via representing their relationships among each other ■ ...relationships can be represented as graphs Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  41. 41. Resource41 Description Framework Framework ■ = Combination of web based protocols (URI, HTTP, XML,...) ■ based on formal model (semantics) ■ defines all allowed relationships among resources Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  42. 42. Resource42 Description Framework ■ Originally developed to define metadata for web resources ■ 1995-1997: proprietary Meta Content Framework (Netscape) ■ 1997 RDF as general description language for metadata, W3C Draft ■ 1998 first RDF W3C recommendation (http://www.w3c.org/RDF) ■ Definition of an XML subset (machine readable) with predefined (fixed) semantics (machine understandable) ■ Simple, universal semantic data model ■ RDF enables high interoperability Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  43. 43. Resource43 Description Framework Harald Sack Subject has phone number Property ++49 (331) 5509-527Object Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  44. 44. Resource44 Description Framework Harald Sack has phone number ++49 (331) 5509-527 ■ Knowledge in RDF is expressed as a list of statements ■ all RDF statements follow the same simple schema Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  45. 45. Resource45 Description Framework Harald Sack Subject has phone number Property ++49 (331) 5509-527Object Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  46. 46. Resource46 Description Framework • Resources: Objects that can be addressed via URI • Properties: Attributes for the description of resources • Statements (RDF-Triple): Resource + Property + Object / Value URI URI URI / Literal Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  47. 47. Resource47 Description Framework Constituents of the RDF-Graphen • URI: • to reference resources uniquely http://hpi-web.de/HaraldSack http://swt1213.blogspot.com/ S O http://hpi-web.de/Personal#writesBlog P Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  48. 48. Resource48 Description Framework Constituents of the RDF-Graphen • Literals: • describe data values that do not have a separate existence • strings, interpretation via datatype http://hpi-web.de/HaraldSack ++49-331-5509-527 S O http://hpi-web.de/Personal#hasPhoneNumber P Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  49. 49. Resource49 Description Framework Constituents of the RDF-Graphen • Literals: • typed literals can be expressed via XML Schema datatypes • Namespace for typed literals: http://www.w3.org/2001/XMLSchema# • Example: “Semantics“^^<http://www.w3.org/2001/XMLSchema#string> • Language Tags denote the (natural) language of the text: • Example: “Semantik“@de , “Semantics“@en Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  50. 50. Resource50 Description Framework Constituents of the RDF-Graphen • Blank Nodes: • Denotes existence of an individual with specific attributes, but without providing an identification or reference htttp://www.hpi-web.de/personal#person S O rfds:type P Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  51. 51. Resource51 Description Framework RDF Representations • Node-Edge-Node Triple http://hpi-web.de/HaraldSack http://swt1213.blogspot.com/ S O http://hpi-web.de/Personal#writesBlog P Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  52. 52. Resource52 Description Framework RDF Representations • N3 Notation • Simple listing of triples • { http://hpi-web.de/HaraldSack, http://hpi-web.de/Personal#writesBlog, http://swt1213.blogspot.com/ } Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  53. 53. Resource53 Description Framework RDF Representations • Turtle (Terse RDF Tripel Language) • Extension of N3 • URIs in angle brackets <Subject> <Prop erty> <Object> <Subject> <Prop . • Literals in quotation marks erty> “Object“ . • Triple ends with a period • Whitespaces will be ignored Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  54. 54. Resource54 Description Framework RDF Representations • Turtle (Terse RDF Tripel Language) <http://hpi-web.de/HaraldSack> <http://hpi-web.de/Personal#writesBlog> <http://swt1213.blogspot.com/>. <http://hpi-web.de/HaraldSack> <http://hpi-web.de/Personal#hasPhoneNumber> “++49-331-5509-527“. Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  55. 55. Resource55 Description Framework RDF Representations • Turtle (Terse RDF Tripel Language) @prefix xsd: <http://www.w3.org/2001/XMLSchema#> . @prefix dc: <http://purl.org/dc/elements/1.1/> . @prefix ex: <http://example.org/stuff/1.0/> . <http://www.w3.org/TR/rdf-syntax-grammar> dc:title "RDF/XML Syntax Specification (Revised)"@en ; ex:editor [ ex:fullname "Dave Beckett"^^xsd:string ; ex:homePage <http://purl.org/net/dajobe/> ]. Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  56. 56. Resource Description Framework56 RDF Representations • RDF XML-Serialization <xml version=“1.0“ encoding=“utf-8“> <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#“ xmlns:pers=“http://hpi-web.de/Personal#“> <rdf:Description rdf:about=“http://hpi-web.de/HaraldSack“> <pers:hasPhoneNr>++49-331-5509-527</pers:hasPhoneNumber> </rdf:Description> <rdf:Description rdf:about=“http://hpi-web.de/HaraldSack“> <pers:writesBlog> <rdf:Description rdf:about=“http://swt1213.blogspot.com/“></rdf:Description> </pers:writesBlog> </rdf:Description> </rdf:RDF> Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  57. 57. Resource Description Framework57 hasPhoneNumber ++49-331-5509-527 Literal http://hpi-web.de/HaraldSack Resource writesBlog http://swt1213.blogspot.com/ Resource <xml version=“1.0“ encoding=“utf-8“> <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#“ xmlns:pers=“http://hpi-web.de/Personal#“> <rdf:Description rdf:about=“http://hpi-web.de/HaraldSack“> <pers:hasPhoneNumber>++49-331-5509-527</pers:hasPhoneNumber> <rdf:Description> <rdf:Description rdf:about=“http://hpi-web.de/HaraldSack“> <pers:writesBlog rdf:resource=“http://swt1213.blogspot.com/“ /> </rdf:Description> </rdf:RDF> Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  58. 58. Resource Description Framework58 hasPhoneNumber ++49-331-5509-527 Literal http://hpi-web.de/HaraldSack Resource writesBlog http://swt1213.blogspot.com/ Resource <xml version=“1.0“ encoding=“utf-8“> <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#“ xmlns:pers=“http://hpi-web.de/Personal#“> <rdf:Description rdf:about=“http://hpi-web.de/HaraldSack“> <pers:hasPhoneNumber>++49-331-5509-527</pers:hasPhoneNumber> <rdf:Description> <rdf:Description rdf:about=“http://hpi-web.de/HaraldSack“> <pers:writesBlog rdf:resource=“http://swt1213.blogspot.com/“ /> </rdf:Description> </rdf:RDF> Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  59. 59. Resource Description Framework59 hasPhoneNumber ++49-331-5509-527 Literal http://hpi-web.de/HaraldSack Resource writesBlog http://swt1213.blogspot.com/ Resource <xml version=“1.0“ encoding=“utf-8“> <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#“ xmlns:pers=“http://hpi-web.de/Personal#“> <rdf:Description rdf:about=“http://hpi-web.de/HaraldSack“ pers:hasPhoneNumber=“++49-331-5509-527“> <pers:writesBlog rdf:resource=“http://swt1213.blogspot.com/“/> </rdf:Description> </rdf:RDF> Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  60. 60. Resource Description Framework60 hasPhoneNumber ++49-331-5509-527 Literal http://hpi-web.de/Dozenten#HaraldSack Resource writesBlog http://swt1213.blogspot.com/ Resource <xml version=“1.0“ encoding=“utf-8“> <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#“ xmlns:pers=“http://hpi-web.de/Personal#“ xml:base=“http://hpi-web.de/Dozenten“> <rdf:Description rdf:about=“#HaraldSack“ pers:hasPhoneNumber=“++49-331-5509-527“> <pers:writesBlog rdf:resource=“http://swt1213.blogspot.com/“/> </rdf:Description> </rdf:RDF> Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  61. 61. Resource Description Framework61 hasPhoneNumber ++49-331-5509-527 Literal http://hpi-web.de/Dozenten#HaraldSack Resource writesBlog http://swt1213.blogspot.com/ Resource @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . @prefix pers: <http://hpi-web.de/Personal#> . @base <http://hpi-web.de/Dozenten> . @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . :HaraldSack pers:hasphoneNumber “++49-331-5509-527“ . @prefix pers: <http://hpi-web.de/Personal#> . :HaraldSack pers:writesBlog <http://swt1213.blogspot.com/> . Short Cut @base <http://hpi-web.de/Dozenten> . :HaraldSack pers:hasPhoneNumber “++49-331-5509-527“ ; pers:writesBlog <http://swt1213.blogspot.com/> . Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  62. 62. Resource Description Framework62 hasPhoneNumber ++49-331-5509-527 Literal http://hpi-web.de/Dozenten#HaraldSack Resource writesBlog http://swt1213.blogspot.com/ Resource <xml version=“1.0“ encoding=“utf-8“> <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#“ xmlns:pers=“http://hpi-web.de/Personal#“ xml:base=“http://hpi-web.de/Dozenten“ <rdf:Description rdf:ID=“HaraldSack“ pers:hasPhoneNumber=“++49-331-5509-527“> <pers:writesBlog rdf:resource=“http://swt1213.blogspot.com/“/> </rdf:Description> </rdf:RDF> Datei http://hpi-web.de/Dozenten.rdf Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  63. 63. Resource Description Framework63 hasPhoneNumber ++49-331-5509-527 Literal http://hpi-web.de/Dozenten#HaraldSack Resource writesBlog http://swt1213.blogspot.com/ Resource @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . @prefix pers: <http://hpi-web.de/Personal#> . :HaraldSack pers:hasPhoneNumber “++49-31-5509-527“ ; pers:writesBlog <http://swt1213.blogspot.com/> . Datei http://hpi-web.de/Dozenten.rdf Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  64. 64. Resource Description Framework64 http://hpi-web.de/Lecture#Name Semantic Web Technologies http://hpi-web.de/ws1213#swt 4 http://hpi-web.de/Lecture#SWS <xml version=“1.0“ encoding=“utf-8“> <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#“ xmlns:lv=“http://hpi-web.de/Lecture#“ > <rdf:Description rdf:about=“http://hpi-web.de/ws1213#swt“> <lv:Name rdf:datatype=“http://www.w3c.org/2001/XMLSchema#string“> Semantic Web Technologies </lv:Name> <lv:SWS rdf:datatype= “http://www.w3c.org/2001/XMLSchema#integer“> 4 </lv:SWS> </rdf:Description> </rdf:RDF> Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  65. 65. Resource Description Framework65 Semantic Web http://hpi-web.de/Lecture#Name Technologies http://hpi-web.de/ws1213#swt 4 http://hpi-web.de/Lecture#SWS @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . @prefix lv: <http://hpi-web.de/Lecture#> . <http://hpi.web.de/ws1213#swt> @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . lv:Name “Semantic Web Technologies“^^<http://www.w3c.org/2001/XMLSchema#string> ; @prefix lv: <http://hpi-web.de/Lecture#> . lv:SWS “4“^^<http://www.w3c.org/2001/XMLSchema#integer> . <http://hpi.web.de/ws1213#swt> lv:Name “Semantic Web Technologies“; lv:SWS 4 . Abgekürzte Schreibweise Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  66. 66. Resource Description Framework66 Multi Valued Relations and Blank Nodes • Example: • A lecture takes place twice a week in two different rooms • How to model this in RDF? http://hpi-web.de/Lecture#hasName Semantic Web Technologies http://hpi-web.de/ws1213#swt http://hpi-web.de/Lecture#hasRoom HS3 http://hpi-web.de/Lecture#hasDate http://hpi-web.de/Lecture#hasRoom Die 13.30-15.00 H-1.52 http://hpi-web.de/Lecture#hasDate Mi 13.30-15.00 Problem: not unique Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  67. 67. Resource Description Framework67 Multi Valued Relations and Blank Nodes • Example: • A lecture takes place twice a week in two different rooms • How to model this in RDF? Semantic Web hpi-lv:hasName Technologies http://hpi-web.de/ws1213#swt hpi-lv:takesPlace hpi-lv:hasRoom HS3 hpi-lv:takesPlace hpi-lv:hasDate hpi-lv:hasRoom Die 13.30-15.00 H-1.52 hpi-lv:hasDate Mi 13.30-15.00 Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  68. 68. Resource Description Framework68 Blank Nodes • Blank Nodes (Bnodes) can be introduced to represend multi valued relationships • Blank Nodes can be introduced for resources that don‘t need a name (auxiliary nodes) Semantic Web hpi-lv:hasName Technologies http://hpi-web.de/ws1213#swt hpi-lv:takesPlace hpi-lv:hasRoom HS3 hpi-lv:hasDate Die 13.30-15.00 Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  69. 69. Resource Description Framework69 Anonymous Blank Nodes hpi-lv:hasName Semantic Web Technologies http://hpi-web.de/ws1213#swt hpi-lv:takesPlace hpi-lv:hasRoom HS3 hpi-lv:hasDate Die 13.30-15.00 <xml version=“1.0“ encoding=“utf-8“> <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#“ xmlns:hpi-lv=“http://hpi-web.de/Lecture#“ > <rdf:Description rdf:about=“http://hpi-web.de/ws1213#swt“> <hpi-lv:takesPlace rdf:parseType=“Resource“/> <hpi-lv:hasDate>Die, 13.30-15.00</hpi-lv:hasDate> <hpi-lv:hasRoom>HS3</hpi-lv:hasRoom> </hpi-lv:takesPlace> </rdf:Description> Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  70. 70. Resource Description Framework70 Anonymous Blank Nodes hpi-lv:hasName Semantic Web Technologies http://hpi-web.de/ws1213#swt hpi-lv:takesPlace hpi-lv:hasRoom HS3 hpi-lv:hasDate Die 13.30-15.00 @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . @prefix hpi-lv: <http://hpi-web.de/Lecture#> . <http://hpi-web.de/ws1213#swt> hpi-lv:takesPlace [ hpi-lv:hasDate “Die 13.30-15.00“; hpi-lv:hasRoom “HS3“ ] . Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  71. 71. Resource Description Framework71 Dereferencable Blank Nodes Semantic Web Technologies hpi-lv:hasName http://hpi-web.de/ws1213#swt hpi-lv:takesPlace hpi-lv:hasRoom ID1 HS3 hpi-lv:hasDate Die 13.30-15.00 <rdf:Description rdf:about=“http://hpi-web.de/ws1213#swt“> <hpi-lv:takesPlace rdf:nodeID=“ID1“/> <rdf:Description> <rdf:Description rdf:nodeID=“ID1“> <hpi-lv:hasDate>Die 13.30-15.00</hpi-lv:hasDate> <hi-lv:hasRoom>HS3<hpi-lv:hasRoom> </rdf:Description> </rdf:RDF> Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  72. 72. Resource Description Framework72 Dereferencable Blank Nodes Semantic Web Technologies hpi-lv:hasName http://hpi-web.de/ws1213#swt hpi-lv:takesPlace hpi-lv:hasRoom ID1 HS3 hpi-lv:hasDate Die 13.30-15.00 @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . @prefix hpi-lv: <http://hpi-web.de/Lecture#> . <http://hpi-web.de/ws1213#swt> hpi-lv:takesPlace _:ID1 . _:ID1 hpi-lv:hasDate “Die 13.30-15.00“; hpi-lv:hasRoom “HS3“ . Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  73. 73. Resource Description Framework73 Lists • General Data structure to enumerate any resoures or literals • Only shortcuts, no additional semantic expressivity • Distinguish between • Container open list, i.e. extension (new entries) possible • Collections closed list, i.e. no extension possible Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  74. 74. Resource Description Framework74 RDF Container http://hpi-web.de/ws1213#swt rdf:_1 http://hpi-web.de/BurgerAnton hpi-lv:hasParticipants rdf:_2 http://hpi-web.de/MuellerFranz rdf:_3 http://hpi-web.de/SchmidtJoseph rdf:type rdf:_4 http://hpi-web.de/SchulzeEgon rdf:Seq @prefix hpi-lv: <http://hpi-web.de/Lecture#> . @prefix rdf: http://www.w3.org/1999/02/22-rdf-syntax-ns#> . Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  75. 75. Resource Description Framework75 RDF Container <rdf:Description rdf:about=“http://hpi-web.de/ws1213#swt“> <lv:hasParticipants> <rdf:Seq> <rdf:li rdf:resource=“http://hpi-web.de/BurgerAnton“ /> <rdf:li rdf:resource=“http://hpi-web.de/MuellerFranz“ /> <rdf:li rdf:resource=“http://hpi-web.de/SchmidtJoseph“ /> <rdf:li rdf:resource=“http://hpi-web.de/SchulzeEgon“ /> </rdf:Seq> </lv:hasParticipants> </rdf:Description> @prefix hpi-lv: <http://hpi-web.de/Lecture#> . @prefix rdf: http://www.w3.org/1999/02/22-rdf-syntax-ns#> . Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  76. 76. Resource Description Framework76 RDF-Container • the root node of the container is assigned a container-typ via rdf:type • rdf:Bag unordered set of elements, there is no given order of elements • rdf:Seq ordered set of elements, • rdf:Alt defines alternatives of elements only one element of the given alternatives is relevant for the application Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  77. 77. Resource Description Framework77 RDF Container @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . @prefix lv: <http://hpi-web.de/Lecture#> . @base <http://hpi-web.de/> :swt lv:hasParticipants [ a rdf:Seq; rdf:_1 <BurgerAnton>; rdf:_2 <MuellerFranz>; rdf:_3 <SchmidtJoseph>; rdf:_4 <SchulzeEgon> . ]. Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  78. 78. Resource Description Framework78 @prefix hpi-lv: <http://hpi-web.de/Lecture#> . RDF-Collection @prefix rdf: http://www.w3.org/1999/02/22-rdf-syntax-ns#> . http://hpi-web.de/ws1213#swt lv:hasParticipants rdf:first http://hpi-web.de/BurgerAnton rdf:rest rdf:first http://hpi-web.de/MuellerFranz rdf:rest rdf:first http://hpi-web.de/SchmidtJoseph rdf:rest rdf:first http://hpi-web.de/SchulzeEgon rdf:rest rdf:nil List is splitted recursively in Head (first) and Tail (rest). Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  79. 79. Resource Description Framework79 RDF-Collection <rdf:Description rdf:about=“http://hpi-web.de/ws1213#swt“> <lv:hasParticipant rdf:parseType=“Collection“> <rdf:Description rdf:about=“http://hpi-web.de/BurgerAnton“ /> <rdf:Description rdf:about=“http://hpi-web.de/MuellerFranz“ /> <rdf:Description rdf:about=“http://hpi-web.de/SchmidtJoseph“ /> <rdf:Description rdf:rabout=“http://hpi-web.de/SchulzeEgon“ /> </lv:hasParticipant> </rdf:Description> Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  80. 80. Resource Description Framework80 RDF-Collection @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . @prefix lv: <http://hpi-web.de/Lecture#> . @base <http://hpi-web.de/> :swt lv:hasParticipant [ rdf:first <BurgerAnton>; rdf:rest [ rdf:first <MuellerFranz>; rdf:rest [ rdf:first <SchmidtJoseph>; rdf:rest [ rdf:first <SchulzeEgon>; rdf:rest rdf:nil . ]]]]. Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  81. 81. Resource Description Framework81 RDF-Collection @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . @prefix lv: <http://hpi-web.de/Lecture#> . @base <http://hpi-web.de/> :swt lv:hasParticipant ( <BurgerAnton> <MuellerFranz> <SchmidtJoseph> <SchulzeEgon>) . Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  82. 82. What can we model with RDF?82 Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  83. 83. Resource Description Framework83 „My dear Watson, ...I suppose that the Gardener has killed the Butler!“ Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  84. 84. Resource Description Framework84 RDF-Reification • RDF permits interleaving of statements, i.e. to make statements about statements • Example: „My dear Watson, ...I suppose that the Gardener has killed the Butler!“ Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  85. 85. Resource Description Framework85 RDF-Reification • RDF permits interleaving of statements, i.e. to make statements about statements • Example: • Sherlock Holmes supposes that the Gardener has killed the Butler •Part 1: The Gardener has killed the Butler exv:Gardener exv:hasKilled exv:Butler . •Part 2: Sherlock Holmes supposes exv:SherlockHolmes exv:supposes ???? . Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  86. 86. Resource Description Framework86 RDF-Reification • rdf:Statement defines an RDF Statement, consisting of Subject, Predicate and Object • rdf:subject - the described resource • rdf:predicate - the original property • rdf:object - the value of the property <rdf:Description rdf:about=“http://example.org/StatementOnGaertner“> <rdf:subject rdf:resource=“http://example.org/Gardener“ /> <rdf:predicate rdf:resource=“http://example.org/Crime#hasKilled“ /> <rdf:object rdf:resource=“http://example.org/Butler“ /> <rdf:type rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#Statement" /> </rdf:Description> Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  87. 87. Resource Description Framework87 RDF-Reification rdf:subject Gardener SherlockHolmes exv:supposes exv:hasKilled rdf:predicate StatementOnGardener Butler rdf:object <rdf:Description rdf:about=“http://example.org/StatementOnGardener“> <rdf:subject rdf:resource=“http://example.org/Gardener“ /> <rdf:predicate rdf:resource=“http://example.org/Crime#hasKilled“ /> <rdf:object rdf:resource=“http://example.org/Butler“ /> <rdf:type rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#Statement" /> </rdf:Description> <rdf:Description rdf:about=“http://example.org/SherlockHolmes“> <exv:supposes rdf:resource=“http://example.org/StatementOnGaertner“ /> </rdf:Description> Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  88. 88. Resource Description Framework88 RDF-Reification rdf:subject Gardener SherlockHolmes exv:supposes exv:hasKilled rdf:predicate StatementOnGardener Butler rdf:object @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . @exv <http://example.org/Crime#> <SherlockHolmes> exv:supposes <StatementOnGardener> . <StatementOnGardener> a rdf:Statement ; rdf:subject <Gardener> ; rdf:predicate exv:hasKilled ; rdf:object <Butler> . Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  89. 89. Resource Description Framework89 RDF-Reification • Is Reification really necessary? • Modeling data provenance • Formalizing statements about Reliability (Trust) • Definition of Metadata about Statements (Assertions, Statements) • for (general) knowledge representation (Ontologie Construction): • Transformation of Relations into Classes Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  90. 90. RDF and Data Integration90 Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  91. 91. RDF and Data Integration91 • Simple Example: Bibliography Database ID Author Title Publisher Year ISBN 0-00-651409-X HS-123 WWW S-001 2004 ID Name Homepage HS-123 Harald Sack http://hpi-web.de/HaraldSack.html ID Publisher Location S-001 Springer Heidelberg Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  92. 92. RDF and Data Integration92 • Database export into a set of relations a:publishername Springer Heidelberg a:publisherlocation a:title a:publisher WWW ISBN 0-00-651409-X a:year 2004 a:author a:authorname Harald Sack http://hpi-web.de/HaraldSack.html a:authorhomepage Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  93. 93. RDF and Data Integration93 Harald Sack u:name a:publishername Springer Heidelberg u:author a:publisherlocation ISBN 0-00-651409-X a:title a:publisher WWW ISBN 0-00-651409-X u:cites a:year 2004 a:author http://.../paper a:authorname Harald Sack u:title http://hpi-web.de/HaraldSack.html Very important paper a:authorhomepage Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  94. 94. RDF and Data Integration94 Harald Sack u:name a:publishername Springer Heidelberg u:author a:publisherlocation ISBN 0-00-651409-X a:title a:publisher WWW ISBN 0-00-651409-X u:cites a:year 2004 a:author http://.../paper a:authorname Harald Sack u:title http://hpi-web.de/HaraldSack.html Very important paper a:authorhomepage Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  95. 95. RDF and Data Integration95 Harald Sack a:publishername Springer u:name Heidelberg a:publisherlocation u:author a:publisher WWW a:title ISBN 0-00-651409-X u:cites a:year 2004 http://.../paper a:authorname Harald Sack u:title a:author http://hpi-web.de/HaraldSack.html Very important paper a:authorhomepage Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  96. 96. RDF - a Resume96 RDF Model -- Summary • An RDF Model is a set of RDF statements • Statement := (subject, property, object) • Subject is a resource • Property is a resource • Object is ether a resource or a literal Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  97. 97. Semantic Web Technologies Content97 2. Semantic Web Basic Architecture The Languages of the Semantic Web - Part 1 • Uniform Resource Identifier - URI • Recapitulation: XML and XMLSchema • Resource Description Framework - RDF • RDF Schema • How Do We Get Semantics into WWW? • µFormats, schema.org, RDFa and GRDDL • Query Language SPARQL • Why RDF(S) is not enough Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  98. 98. S Next lecture98 D F R SO ... WE NEED A WAY TO DEFINE RDF SCHEMATA FOR CLASSES AND RELATIONS ?! Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  99. 99. 2. Semantic Web Basic Architecture 2.1 Uniform Resource Identifier 2.2 XML und XMLSchema 2.3 Resource Description Framework99 Bibliography • Ch. Meinel, H. Sack: WWW - Kommunikation, Internetworking, Webtechnologien, Springer, 2004. • D. R. Hofstadter: Gödel, Escher, Bach - ein endlos geflochtenes Band, Dtv, 1992. Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDienstag, 23. Oktober 12
  100. 100. 2. Semantic Web Basic Architecture 2.1 Uniform Resource Identifier 2.2 XML und XMLSchema 2.3 Resource Description Framework100 Bibliography • P. Hitzler, S. Roschke, Y. Sure: Semantic Web Grundlagen, Springer, 2007. • P. Hitzler, M. Krötzsch, S. Rudolph: Foundations of Semantic Web Technologies, CRC Press, 2009. Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam Dienstag, 23. Oktober 12
  101. 101. 2. Semantic Web Basic Architecture 2.1 Uniform Resource Identifier 2.2 XML und XMLSchema 2.3 Resource Description Framework101 □Blog http://semweb2013.blogspot.com/ □Webseite http://www.hpi.uni-potsdam.de/studium/ lehrangebot/itse/veranstaltung/ semantic_web_technologien-3.html □bibsonomy - Bookmarks http://www.bibsonomy.org/user/lysander07/ swt1213_02 Lecture Semantic Web Technologies, Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam Dienstag, 23. Oktober 12

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