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OntologiesandFolksonomies

SocialComputingClass2009

u ta ass eva

UniversityofSaskatchewan

SOFIA: http://picasaweb.google.ca/julitav/DropBox?authkey=Gv1sRgCK-3v5mB5a38Dg#5399921463445091762

HowtoorganizetheWebsothat

wecanfindstuff?

TheSemanticWeb:(T. Berners-Lee et al., 2001)... is an extension of the current web in which information is iven well-defined...

meaning, better enabling computers and people to work in co-operation.

RuleInterchang

Query language for RDF Format

Metadata: syntax

Metadata: semantics

Things/objects

Ontology:

Defines thvocabular

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Approachestoorganizeknowledge

ThePhilosophical/ArtificialIntelligenceapproach Ontologies (fromWikipedia): Ontology (fromthe Greek ,genitive : ofbeing (neuterparticiple

of: tobe)and , logia: science, study, theory)isthephilosophical studyofthenatureofbeing, existence or reality ingeneral,as

wellasofthebasic categoriesofbeing andtheirrelations.

In computerscience and informationscience,an ontology isaformal

representationofasetofconceptswithinadomain andtherelationships

betweenthoseconcepts.Itisusedto reason aboutthepropertiesofthat

domain,andmaybeusedtodefinethedomain.Anontologyisa"formal,

explicitspecificationofasharedconceptualization".[1] Anontologyprovidesa

sharedvocabulary,whichcanbeusedtomodeladomain

TheSocialWebapproach

TagsandFolksonomies

Ontologies

TaxonomiesLa ers la ers la ersofmetadataVariousmetadatastandards

WordNet

LetsplayastandardsAcronymtrivia:

XCBF,XKMS,SAML,XACML,WSML

,Sincethemid1970s,researchersinthefieldofartificialintelligence haverecognizedthatcapturingknowledgeisthekeytobuildinglargeandpowerfulAIsystems.AIresearchersarguedthattheycouldcreatenewontologiesas computationalmodels thatenablecertainkindsofautomatedreasoning.

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Metadata

HTML provides formatting

Social Com utin

RDF provides metadata about web resources

Teacher Name

Student Name

XML provides syntax

6086758

RDF Schema adds vocabulary for RDF.

Organizes the vocabulary in typed hierarchySocial Computing

Teacher Name

Student Name

- Class, subClassOf, type

- Property, subPropertyOf- Domain, range

RDF(resourcedescriptionframework)RDF is based on the idea of identifying things using Web identifiers(called Uniform Resource Identifiers, or URIs), and describing resources in terms of

simple properties and property values.

Eric Miller

Dr.

RDF Identifies:

individuals e Eric M iller, . ., ,

identified by http://www.w3.org/People/EM/contact#mekinds of things, e.g., Person,identified by http://www.w3.org/2000/10/swap/pim/contact#Person

properties of those things, e.g., mailbox,identified by http://www.w3.org/2000/10/swap/pim/contact#mailbox

values of those properties, e.g. mailto:em@w3.org as the value of the mailbox property

RDF Tutorial (30 min)

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Ontologies

OntologycomponentsandlanguagesCommon components of ontologies include (Wikipedia)

" "

Classes: sets, collections, concepts, types of objects, or kinds of things.[10]

Attributes: aspects, properties, features, characteristics, or parameters that objects

(and classes) can haveRelations: ways in which classes and individuals can be related to one another

Function terms: complex structures formed from certain relations that can be used

in place of an individual term in a statementRestrictions: formally stated descriptions of what must be true in order for some

assertion to be accepted as input

Rules: statements in the form of an if-then (antecedent-consequent) sentence thatdescribe the logical inferences that can be drawn from an assertion in a particular

formAxioms: assertions (including rules) in a logical form that together comprise the

overall theory that the ontology describes in its domain of application.Events: the changing of attributes or relations

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Ontologylanguages

An ontology language is a formal language used to encode the ontology.

IDEF5 is a software engineering method to develop and maintain usable,

accurate, domain ontologies.

KIF is a syntax for first-order logic that is based on S-expressions.

Rule Interchange Format (RIF) and F-Logic combine ontologies and rules.

OWL is a language for making ontological statements, developed as a

follow-on from RDF and RDFS, as well as earlier ontology language

projects including OIL, DAMLand DAML+OIL. OWL is intended to be used, ,

individuals) are defined as RDF resources, and identified by URIs.

Example:FOAFontologyforsocial

relationships

http://www.foafproject.org/ C asses:

| Agent | Document | Group | Image | OnlineAccount | OnlineChatAccou

nt | OnlineEcommerceAccount |OnlineGamingAccount | Organization | P

erson | PersonalProfileDocument | Project |

Properties:

| accountName | accountServiceHomepage| aimChatID | based_near | b

irthday | currentProject | depiction | depicts| dnaChecksum | family_nam

t | homepage | icqChatID |img | interest | isPrimaryTopicOf | jabberID | k

nows | logo | made | maker | mbox | mbox_sha1sum | member | memb

ershipClass| msnChatID | myersBriggs | name | nick | openid | page | pas

tProject | phone | plan | primaryTopic | publications |schoolHomepage |

sha1 | surname | theme | thumbnail | tipjar | title | topic | topic_interest

| weblog | workInfoHomepage |workplaceHomepage | yahooChatID |

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Attemptstoharvestontologypower

OntologySearchengineSwoogle:http://swoogle.umbc.eduhttp://ebiquity.umbc.edu/project/html/id/53/ (description)

Butitworksonlyforsemanticallyannotatedsites Humansannotatingcontent currentlythemost

commonapproach

Buthowtoannotatedynamicservicecontentefficiently?

,constructingdeepdatasignaturefordocsand

services,thenfrequencydistributionanalysesandclusteringactiveareaofresearch

HowdoYOUorganize

Yourkitchencupboards?

Yourclothesinthecloset?

Thefilesonyourcomputer?

Yourdigitalphotos?

The solution to overabundance of data is more data

David Weinberger

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Principlelimitationsofontologies

Anontologyalwaysreflectsaparticular,

E.g.librarycataloguesoptimizebookshelves physicallocationofbooksinlibrary(onebookinjustonecategory)

worldviewatthetimeofcataloguing Dewey, 200: Religion210 Natural theology220 Bible230 Christian theology240 Christian moral & devotional theology

250 Christian orders & local church260 Christian social theology270 Christian church histor

A: Marxism-LeninismA1: Classic works of Marxism-LeninismA3: Life and work of C.Marx, F.Engels, V.I.LeninA5: Marxism-Leninism PhilosophyA6: Marxist-Leninist Political Economics

280 Christian sects & denominations290 Other religions

DK: Former Soviet UnionDL: ScandinaviaDP: Iberian PeninsulaDQ: SwitzerlandDR: Balkan PeninsulaDS: AsiaDT: AfricaDU: OceaniaDX: Gypsies

A7/8: Scientific Communism

D: History (general)DA: Great BritainDB: AustriaDC: FranceDD: GermanyDE: MediterraneanDF: GreeceDG: ItalyDH: Low CountriesDJ: Netherlands

Hierarchiesandnonhierarchies

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Example Yahoo

Moreproblems Categorizinghasaspectsof

Mindreading(guessinghowotherswillinterpret)

Categorizingleadstoinformationloss

E.g.categoryofinterest:movies,films,cinema aretheyallthesamereally?

Smartpeoplethinkdifferently

Differentcommunitieshaveimplicitnamingagreements:hardtofindconsensus

Hardtoagreeuponthesemanticsofrelationships Evenifpeopleagreeformally,theymaystillinterpret

differently

Evensimplehierarchiesarehardtouse

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Useoftaxonomybasedannotation

17

Howtoimposeanontologyfordiverseandautonomoususers?

OnlythesimplestofthesimplehasachanceButatthatlevelofsimplicity,isitstilluseful?

SummaryWhendoesOntologicalClassificationworkwell?

Smallcor us

FormalcategoriesStableentitiesRestrictedentitiesClearedges

WhendoesOntologicalClassificationNOTworkwell?

Authoritative source of judgment

Coordinated users

Expert users

LargecorpusNoformalcategoriesUnstableentitiesUnrestrictedentitiesNoclearedges

Uncoordinated usersAmateur users

Naive catalogersNo Authority

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Folksonomies

19KeynoteITS'2008

Folksonomies(web2.0)

PositivesSelfishusersta forthemselvesEasytoaddTagscanexpressdifferentsemanticdimensions:content,

context,pedagogical,learnertype,mediatype, >similartometadata

Nostandards(just helpinavoidingmisspellings)Tagsharingleadstosocialqualitycontrol

,Tagcloudgivesasummaryofdocument(browsing)Allowseasysearchbytag(insteadofformingqueries)

20KeynoteITS'2008

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Folksonomies problems:

Themachinedoesnotknowthesemanticsoft e ocumentw t out now ng owt etags

relatetoeachother(i.e.anontologyoftags)

Cantsayhowtwodocumentsarerelatedorwhytheyaresimilar(notqualitatively)

Hardtosequenceapresentationfromtagged

materials

Butforaoneshotretrievaltagsareokay.

21KeynoteITS'2008

DATAMININGOFUSERCONTENTONTOLOGY

Snaptogrid(Gruber)

Contributetags

Suggesttags

Tagging

Ontologies /Semantic web

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Featuresofthesesolutions

Usercentered respectusersautonomy

Easyfortheuser justlikeafolksonomy

TheAIhappensinthebackground,theuserisnotawareofit

Simplicityandeaseofusepreserved,a van ageso on o ogya e

http://www.bazaarblog.com/2007/10/28/everythingismiscellaneousastoldbyvideo/