FOAF 1272020 1 Introduction l Metadata is data

FOAF 12/7/2020 1

Introduction l Metadata is data about data l l The terms refer to data used to identify, describe, or locate information resources Metadata helps manage and use large collections of information l 12/7/2020 Library card catalogs are example of metadata 2

Popular Schemas l l l l Dublin Core FOAF FRBR Creative Commons SKOS Geo See http: //www. schemaweb. info/ 12/7/2020 3

FOAF: Friend of a friend “The Friend of a Friend (FOAF) project is about creating a Web of machinereadable homepages describing people, the links between them and the things they create and do. ” (http: //www. foaf-project. org/) l Annotation vocabulary for linking semantic information about people to achieve a social network l Everybody can provide/link his/her own Foa. F file on his/her own webpage. l Related to the success of “social networks”: friendster, orkut, ryze, Linked. In etc. But: these use disclosed applications/databases/portals instead whereas Foaf is intended to work decentralized and based on RDF. Reference: FOAF Vocabulary Specification 0. 91: http: //xmlns. com/foaf/spec/ 12/7/2020 4

FOAF Vocabulary: See details at http: //xmlns. com/foaf/0. 1/ 12/7/2020 5

Basic example <foaf: Person rdf: about="#me" xmlns: foaf="http: //xmlns. com/foaf/0. 1/"> <foaf: name>Dan Brickley</foaf: name> <foaf: mbox_sha 1 sum>241021 fb 0 e 6289 f 92815 fc 210 f 9 e 9137262 c 252 e</foaf: mbox_sha 1 sum> <foaf: homepage rdf: resource="http: //danbri. org/" /> <foaf: img rdf: resource="/images/me. jpg" /> </foaf: Person> 12/7/2020 6

FOAF: Basic Idea l To a computer, 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. Adding semantics to the Web involves two things: allowing documents which have information in machine-readable forms, and allowing links to be created with relationship values. Only when we have this extra level of semantics will we be able to use computer power to help us exploit the information to a greater extent than our own reading. - Tim Berners-Lee "W 3 future directions" keynote, 1 st World Wide Web Conference Geneva, May 1994 12/7/2020 7

FOAF: Basic Idea l l FOAF aims to create a linked information system about people, groups, companies and other kinds of thing. If people publish information in FOAF document format, machines will be able to make use of that information. If those files contain “see also” references to other such documents in the Web, we will have a machine -friendly version of today’s hypertext web FOAF documents are usually represented in RDF. 12/7/2020 8

FOAF basic concepts l foaf: Agent l l l foaf: Document l l Sublcass: foaf: Image foaf: Person l l An agent (eg. , person, group, software or physical artifact) Subclass: foaf: Person, foaf: Organization, foaf: Group A person foaf: Project l 12/7/2020 A project 9

FOAF basic properties l l foaf: family_name foaf: first. Name foaf: homepage foaf: knows l l A person known by this person foaf: mbox_sha 1 sum foaf: title l 12/7/2020 Personal title (Mr, Mrs, Ms, Dr, etc. ) 10

Create your own FOAF l l l http: //www. ldodds. co m/foafa-matic Fill in the detail of yourself It will create FOAF in RDF 12/7/2020 <rdf: RDF xmlns: rdf="http: //www. w 3. org/1999/02/22 -rdf-syntax-ns#" xmlns: rdfs="http: //www. w 3. org/2000/01/rdf-schema#" xmlns: foaf="http: //xmlns. com/foaf/0. 1/" xmlns: admin="http: //webns. net/mvcb/"> <foaf: Person rdf: ID="me"> <foaf: name>Ying Ding</foaf: name> <foaf: title>Mrs. </foaf: title> <foaf: givenname>Ying</foaf: givenname> <foaf: family_name>Ding</foaf: family_name> <foaf: mbox_sha 1 sum>f 782 acba 4 fc 1 c 1 bbecefc 41 fe 2696 fa 62 a 84 dfe 5</foaf: mbox_sha 1 sum> <foaf: homepage rdf: resource="www. yingding. com"/> <foaf: depiction rdf: resource="me. jpg"/> <foaf: phone rdf: resource="tel: 0043 -512 -5076488"/> <foaf: workplace. Homepage rdf: resource="www. iu. edu"/> <foaf: work. Info. Homepage rdf: resource="www. iu. edu/ying"/> <foaf: school. Homepage rdf: resource="www. uibk. ac. at"/> <foaf: knows> <foaf: Person> <foaf: name>Stefan Decker</foaf: name> <foaf: mbox_sha 1 sum>1 bc 1 f 862 b 688 a 45 b 7 e 0 c 8 d 4 a 8467 c 23177 c 53 fad</foaf: mbox_sha 1 sum> <rdfs: see. Also rdf: resource="www. semanticweb. org"/></foaf: Person></foaf: knows> <foaf: Person> <foaf: name>Ioan Toma</foaf: name> <foaf: mbox_sha 1 sum>1 e 9 f 327 c 5 c 745341 ad 13710805961 aa 739861904</foaf: mbox_sha 1 sum> <rdfs: see. Also rdf: resource="www. ubik. ac. at/Ioan"/></foaf: Person></foaf: knows></foaf: Person> 11 </rdf: RDF>

Publish your FOAF description l Save your FOAF RDF file into your website somewhere and name it usually as “foaf. rdf” 12/7/2020 12

FOAF Example in RDF/XML <rdf: RDF xmlns: rdf="http: //www. w 3. org/1999/02/22 -rdf-syntax-ns#" xmlns: foaf="http: //xmlns. com/foaf/0. 1/"> <foaf: Person> <foaf: name>John Breslin</foaf: name> <foaf: mbox rdf: resource="mailto: John. Breslin@deri. org"/> <foaf: knows> <foaf: Person> <foaf: name>Stefan Decker</foaf: name> <foaf: mbox rdf: resource="mailto: stefan. decker@deri. org"/> </foaf: Person> </foaf: knows> </foaf: Person> </rdf: RDF> foaf: Person rdf: type foaf: knows foaf: name John Breslin 07. 12. 2020 foaf: mbox foaf: name mailto: John. Breslin@deri. org Stefan Decker mailto: Stefan. Decker@deri. org 13

FOAF Conclusions l l Vocabulary for machine-processable personal homepages currently some preliminary tools available not yet as successful as social networks such as friendster, which use proprietary central data advantage of foaf: decentralized, could serve as exchange format between those existing networks and exists on its own 12/7/2020 14