Semantic Web in Action

Slide 1: Digital Enterprise Research Institute www.deri.ie Semantic Web in Action Stefan Decker, Eyal Oren, Sebastian R. Kruk  Copyright 2007 Digital Enterprise Research Institute. All rights reserved. www.deri.org

Slide 2: Outline Digital Enterprise Research Institute www.deri.ie Introduction about DERI  Interlinking online communities: SIOC  Application development: ActiveRDF & BrowseRDF  Sharing and interconnecting knowledge: JeromeDL  Summary  2

Slide 3: DERI Galway – Mission Digital Enterprise Research Institute www.deri.ie DERI Galway’s mission is “to exploit semantics for helping – people – organisations – systems to better collaborate and interoperate”. 3

Slide 4: Some statistics Digital Enterprise Research Institute www.deri.ie Founded June 2003 with 1 fulltime member  Status May 2007: 98 members  Core fulltime research active members:  2 Professors  6 additional senior scientific researchers  9 PostDocs  5 Research Staff  58 PhD, Master Students & Interns  18 members are administration & management,  industry and community outreach, university liaison, subcontractors Still hiring aggressively  4

Slide 5: What is the Semantic Web? (beware the hype) Digital Enterprise Research Institute www.deri.ie  “An extension of the current Web in which information is given well-defined meaning, better enabling computers and people to work in cooperation.” – Sir Tim Berners-Lee et al., Scientific American, 2001: tinyurl.com/i59p  “…allowing the Web to reach its full potential…” with far-reaching consequences  “The next generation of the Web” 5

Slide 6: The Semantic Web (so far) Digital Enterprise Research Institute www.deri.ie 6

Slide 7: Social semantic information spaces: SW 2.0 Digital Enterprise Research Institute www.deri.ie Web 2.0 and social software 7

Slide 8: Digital Enterprise Research Institute www.deri.ie SIOC: Semantically Interlinked Community Sites Stefan Decker  Copyright 2007 Digital Enterprise Research Institute. All rights reserved. www.deri.org

Slide 9: What is SIOC? Digital Enterprise Research Institute www.deri.ie Semantically-Interlinked Online Communities (SIOC)  Connecting many types of online communities  (blogs, forums, mailing lists, etc.) Interesting possibilities:  Distributed linked conversations  Decentralised discussion channels and communities  “I […] think the concept is HOT” – Robert Douglass,  Drupal Developer 9

Slide 10: Digital Enterprise Research Institute www.deri.ie 10

Slide 20: SIOC Ontology Digital Enterprise Research Institute www.deri.ie 20

Slide 21: How can SIOC data be used? Digital Enterprise Research Institute www.deri.ie 21

Slide 22: Digital Enterprise Research Institute www.deri.ie Browsing SIOC with TimeLine (1) 22

Slide 23: Digital Enterprise Research Institute www.deri.ie Browsing SIOC with TimeLine (2) 23

Slide 24: How can SIOC disseminated? Digital Enterprise Research Institute www.deri.ie Create SIOC export modules for popular open-source  discussion systems Infecting the Web Infrastructure:  During next upgrade cycle gigabytes of community data  become available SIOC metadata exporters created for:  Content management system (Drupal)  Bulletin board system (phpBB)  Blogging system (WordPress)  French blogging system (DotClear)  24

Slide 26: Next steps: Add Onion Rings of Vocabularies Digital Enterprise Research Institute www.deri.ie RDF Calendar Microformats 26

Slide 27: Digital Enterprise Research Institute www.deri.ie Semantic Web application development: ActiveRDF and BrowseRDF Eyal Oren  Copyright 2007 Digital Enterprise Research Institute. All rights reserved. www.deri.org

Slide 28: Semantic Web applications: Digital Enterprise Research Institute www.deri.ie Database-driven web applications Semantic Web applications Centralised Decentralised One fixed schema Semi-structured One fixed vocabulary Arbitrary vocabulary Centralised publishing Publish anywhere One datasource Many distributed datasources Closed systems Open systems 28

Slide 29: Motivation Digital Enterprise Research Institute www.deri.ie relational web applications: web application framework object- relational mapping database 29

Slide 30: Motivation Digital Enterprise Research Institute www.deri.ie relational web applications: web application framework object- relational mapping database 30

Slide 31: Motivation Digital Enterprise Research Institute www.deri.ie relational web semantic web applications: applications: web application framework object- relational mapping database 31

Slide 32: Motivation Digital Enterprise Research Institute www.deri.ie relational web semantic web applications: applications: web application framework object- relational mapping database data source 32

Slide 33: Motivation Digital Enterprise Research Institute www.deri.ie relational web semantic web applications: applications: web application framework object- relational mapping database RDF store data source 33

Slide 34: Motivation Digital Enterprise Research Institute www.deri.ie relational web semantic web applications: applications: web application ??? framework ??? object- relational mapping database RDF store data source 34

Slide 35: Motivation Digital Enterprise Research Institute www.deri.ie relational web semantic web applications: applications: web application ??? Ruby on Rails framework ??? object- ActiveRDF relational mapping database RDF store data source 35

Slide 36: ActiveRDF: RDF(S) to OO mapping Digital Enterprise Research Institute www.deri.ie Intuitive mapping:  RDF(S) classes to OO classes  RDF resources to OO objects  RDF triples to OO attribute values  foaf:Person a rdfs:Class. john a foaf:Person. john foaf:name “John Breslin”. Person john: Person name:string name: “John Breslin” 36

Slide 37: ActiveRDF examples Digital Enterprise Research Institute www.deri.ie print names of john’s friends find all 30-year olds named John 37

Slide 38: ActiveRDF architecture Digital Enterprise Research Institute www.deri.ie proxy objects represent RDF resource, convert methods into queries abstract query API manages collection of data sources wraps RDF store with its own API 38

Slide 39: ActiveRDF object manager Digital Enterprise Research Institute www.deri.ie Represents RDF resources (including RDFS classes) through  proxy objects Intercepts each method call, converts method call into  read/write query Intercepts all dynamic finders calls, converts into query  print john.foaf::name  john.foaf::knows << jack  FOAF::Person.find_all  39

Slide 40: ActiveRDF adapters Digital Enterprise Research Institute www.deri.ie Abstract RDF (or other) data into homogeneous API  SPARQL endpoints, Sesame, Jena, YARS, Redland, ...  Application data (e.g. Evolution emails)  Desktop metadata (e.g. Apple Spotlight metadata)  Reuse ActiveRDF framework with arbitrary data sources  40

Slide 41: Problems with intuitive mapping Digital Enterprise Research Institute www.deri.ie RDF Schema ≠ OO class definition  OO: class membership determines instance behaviour  RDF(S): instance behaviour determines class membership  several consequences, e.g. RDF(S) properties propagate upwards  See (Oren et al., WWW2007) for details and solutions  41

Slide 43: Faceted browsing example: iTunes Digital Enterprise Research Institute www.deri.ie 43

Slide 44: Faceted browsing: limitations Digital Enterprise Research Institute www.deri.ie facets manually configured for a fixed domain  music: genre, artist, album, title  books: title, author, publisher  recipes: ingredients, cuisine, calories, preparation time  facets do not (fully) exploit interconnected data  assume data homogeneity  focus on one resource type (e.g. songs)  only facets of songs, not of singers, albums, publishers    44

Slide 45: Faceted browsing on the Semantic Web Digital Enterprise Research Institute www.deri.ie faceted browsing is query construction   SELECT ?x WHERE ?x author ?a and ?a age “30”. facets in semantic web data:  information space: set of triples  elements of interest: set of subjects  facets: set of properties  now identify operators ...  45

Slide 46: Selection operators Digital Enterprise Research Institute www.deri.ie all single people all thirty-year-olds all people who know somebody with a friend called Stefan 46

Slide 47: Intersection operator Digital Enterprise Research Institute www.deri.ie all single thirty-year-olds that know somebody who has a friend called Stefan 47

Slide 48: Inverse operators Digital Enterprise Research Institute www.deri.ie all working people all DERI employees all people working for an Irish company 48

Slide 49: Interface construction algorithm Digital Enterprise Research Institute www.deri.ie select resources select ?s where ... (constrain information space) select facets select ?p where ... (arcs in constrained space) rank facets (identify most interesting facets) 49

Slide 50: Facet browsing: decision tree Digital Enterprise Research Institute www.deri.ie faceted browsing: constructing & traversing decision  tree ... 50

Slide 51: Facet ranking: optimise decision tree Digital Enterprise Research Institute www.deri.ie decision tree affects navigation efficiency  cardinality  author: 300 values (all names unique)  publisher: 5 values (only few topics)  balance  publisher: Springer (82%), rest (18%)  topic: logic (30%), p2p (30%), web (40%)  frequency  location 5% (almost never given)  author 100% (no anonymous publications)  51

Slide 52: SIOC explorer Digital Enterprise Research Institute www.deri.ie Aggregate online community sources  Dynamic faceted navigation  Built on ActiveRDF and Ruby on Rails  52

Slide 53: Digital Enterprise Research Institute www.deri.ie JeromeDL the Semantic Digital Library Sharing and Interconnecting Knowledge Sebastian R. Kruk  Copyright 2007 Digital Enterprise Research Institute. All rights reserved. www.deri.org

Slide 54: Motivation Digital Enterprise Research Institute www.deri.ie How to integrate and search information from different  bibliographic sources? How to share and interconnect knowledge among  people? 54

Slide 55: Yesterday’s world of digital content Digital Enterprise Research Institute www.deri.ie Digital library  Database and archive (storage)  Digital bibliographic descriptions (metadata)  Full-text search (interface)  Pros:  Content accessible online  Federations of libraries – visit less places  Cons:  Lonely user  No one to talk to, we need to find the right keywords, what if we  do not know them (“man without an ear” paintings example) Still many problems with interconnecting (different) libraries  55

Slide 56: Tomorrow of interconnected, social media Digital Enterprise Research Institute www.deri.ie Social Semantic Information Spaces  Semantic description (interconnected metadata)  Annotations provided by users (social metadata)  Collaborative search and browsing (interface)  Features  Search and browsing based on semantics empowers users  Users contribute to the classification process  Users can understand community driven annotations  Users enhance digital content using blogs, wikis on the  side RDF provides bases for interconnection of digital libraries  56

Slide 57: JeromeDL - Properties Digital Enterprise Research Institute www.deri.ie Support for different kinds of metadata  (DublinCore, BibTeX, MARC21) Supporting users and communities:  users have control over their profile information;  community-aware profiles integrated with bibliographic  descriptions support for community-generated knowledge 

Slide 58: Metadata and Services in JeromeDL Digital Enterprise Research Institute www.deri.ie 58

Slide 59: Semantic Metadata and Services Digital Enterprise Research Institute www.deri.ie 59

Slide 60: Browsing the data graph – why? Digital Enterprise Research Institute www.deri.ie The search does not end on a (long) list of results  The results are not a list (!) but a graph  „Lost in hyperspace”  A need for unified UI and services for filter/narrow  and browse/expand services Share browsing experience – navigate  collaboratively 60

Slide 61: Browsing the data graph – how? Digital Enterprise Research Institute www.deri.ie Defines REST access to services and their  composition Basic services: access, search, filter, similar,  browse, combine Meta services: RDF serialization, subscription  channels, service ID generation, Context services: manage contexts, manage service  calls/compositions in the context, lists contexts Statistics services: properties, values,  tokens 61

Slide 62: Browsing the data graph Digital Enterprise Research Institute www.deri.ie JeromeDL exploits interconnected data  62

Slide 63: Browsing the data graph Digital Enterprise Research Institute www.deri.ie … to allow browsing  63

Slide 64: Semantic Metadata and Services Digital Enterprise Research Institute www.deri.ie 64

Slide 65: Social Semantic Collaborative Filtering Digital Enterprise Research Institute www.deri.ie Why?  The bottom-line of acquiring knowledge: informal  communication (“word of mouth”) How?  Everyone classifies (filters) the information in bookmark  folders (user-oriented taxonomy) Peers share (collaborate over) the information  (community-driven taxonomy) Result?  Knowledge “flows“ from the expert  through the social network to the user System amass a lot of information  on user/community profile (context) 65

Slide 66: Social Semantic Collaborative Filtering Digital Enterprise Research Institute www.deri.ie Problems?  The horizon of a social network (2-3 degrees of  separation) How to handle fine-grained information (blogs, wikis,  etc.) Solutions?  Inference engine to suggest knowledge from the  outskirts of the social network Support for SIOC metadata:  – SIOC browser in SSCF – Annotations and evaluations of “local” resources 66

Slide 67: Social Semantic Collaborative Filtering Digital Enterprise Research Institute www.deri.ie foaf:knows xfoaf:include xfoaf:bookmark 67

Slide 68: Summary Digital Enterprise Research Institute www.deri.ie Some of DERI’s open-source SemWeb technology:  Online communities metadata: SIOC  http://sioc-project.org Data mapping: ActiveRDF  http://activerdf.org Semantic Content Repository: JeromeDL  http://jeromedl.org Faceted navigation: BrowseRDF, MultiBeeBrowse  http://browserdf.org Social knowledge sharing: SSCF  http://s3b.corrib.org Much more: http://deri.ie  68

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