Transcript 슬라이드 1
Towards Semantically-Interlinked Online Communities John G. Breslin, Andreas Harth, Uldis Bojars, and Stefan Decker Digital Enterprise Research Institute (DERI) Galway, Ireland 2008. 11. 26 Summarized and presented by Seungseok Kang Introduction • SIOC (pronounced “shock”) – Semantically-Interlinked Online Communities – Interconnect online communities on the web • Bulletin boards • Weblogs • Mailing lists – Facilitate the location of related and relevant information • Cross-site querying • Topic-related searches • Importing of SIOC data into other systems • By the way, why do we discuss about SIOC? – It’s an example of Semantic Web 2.0 • Semantic Web efforts is mainly towards interlinking application • Web 2.0 is about providing user application – These are not mutually exclusive! – Successful example? What is Web 2.0? • http://en.wikipedia.org/wiki/Web_2.0 – “Web 2.0 … has … come to refer to what some people describe as a second phase of architecture and application development for the World Wide Web.” • Web 2.0 focuses include : – – – – The Web as a platform for social and collaborative exchange Reusable community contributions Subscriptions to information, news, data flows, services Mass-publishing using web-based social software For Communication and Collaboration What is Semantic Web? • Tim Berners-Lee (2001) – “An extension of the current Web in which information is given well-defined meaning, better enabling computers and people to work in cooperation.” – Allowing the Web to reach its full potential – The next generation of the Web W3C’s Semantic Web Stack Commonly quoted problems • Ontologies are difficult to create and are not used – Not worth the effort • Annotation is expensive – Regular user won’t bother • Metadata provides no benefits – No consumers • Standards are too complicated – Developers don’t understand Description Logics One of the Answer is… • Metaweb – Combination of Web 2.0 and Semantic Web – Social semantic information spaces Source : John Breslin, Stefan Decker, “Semantic Web 2.0: Creating Social Semantic Information Spaces”, 2006, DERI Social Semantic Information Spaces Creating Semantic Web Data: Semantic Interlinking of Online Community Sites Source : Stefan Decker’s talk, “Towards Semantic Web 2.0 – Creating Social Semantic Information Spaces”, 2006, DERI Evolution of Online Communities • Online community sites: – Provide a valuable source of information – May contain rich meta-information – But are isolated from one another: • Many sites discussing complementary topics • Next steps: – Connect sites together – Add more value: • Let other sites know more about the structure and contents • Make more use of tagging and semantic metadata • So, we need SIOC! What is SIOC? • Semantically-Interlinked Online Communities – Connecting forums, posts from many types of online communities ( blogs, forums, mailing lists, etc.) – Interesting possibilities: • Distributed linked conversations • Decentralised discussion channels and communities • Typical Usage Scenario – A user is searching for information on installing broadband on a Linux-based PC • Post A discusses local ISPs in bulletin board • Post B compares broadband models on Usenet • Post C details how to install broadband on Linux in mailing list post – Previously the user had to traverse three sites to find the relevant information – By using SIOC, a search for broadband on bulletin board will also yield the relevant text from interlinked Usenet and mailing list post Challenges of SIOC • Adoption SIOC by community sites – By using concepts that can be easily understood by site admin – By providing properties that are automatically created by enduser • How best to use SIOC with existing ontologies – By mapping and interfacing to commonly-used ontologies • Dublin Core • FOAF • How SIOC will scale – Keep the scaling challenge in mind (……) 11 12 13 14 15 16 17 18 19 20 Source : Stefan Decker’s talk, “Towards Semantic Web 2.0 – Creating Social Semantic Information Spaces”, 2006, DERI SIOC Ontology • Main concepts in online communities SIOC Ontology (cont’d) • Main classes – Site • Location of an online community – Forum • A channel or discussion area on which posts are made – Post • An article or message posted by a user to a forum – Event • A virtual or real-world event with a single or multiple participants – Group • A set of members or users of a community site who have a common role – User • A person who is a member of an online community Overview of classes and properties used in SIOC SIOC Ontology (cont’d) • Important properties – Topic • Assigning topics to SIOC primitives • Applies to most of the concepts defined – Views • The number of times a particular post of user profile has been viewed – Has_sibling • Copied posts from one forum to another relevant forum • Non-identical twins that share most characteristics but differ in some manner – Closed • The date and time that the post or forum was closed – Has_creator • A post to the user profile of its author • Used in following the link from the post to the creator and locate the other posts by the same person – Knows • Showing the structure of social networks inside the community sites Mapping • For exchanging community instance data – Leveraging the instance data that is already available – SIOC provide mappings in RDFS and OWL • To allow the import and export of SIOC instance in different vocabularies Selected SIOC mappings • Mappings in SIOC is not only restricted to ontologies – Mapping from XML documents, RSS format, or Email into the SIOC ontology using XSL stylesheets Exchanging Instances • Core use of SIOC – Exchange of instance data between sites – Wrappers to existing tools • Legacy systems • Web-based systems – Document-based wrapping • Mirror data in RDF store – Disseminating solution for newly-developed applications • Native RDF store How can SIOC disseminated? • Legacy systems – Email, IRC, Usenet, and so on… – Need to employ protocol wrappers for legacy protocols to HTTP – Example : Email wrapper • Export – Accepts a conjunctive query over HTTP GET and returns the results in SIOC – The query is parsed and translated into IMAP4 to send to the original data store – Original data store returns the result in RFC822 format – It translated back into RDF and returned to the original caller via HTTP • Import – Receives sioc:Posts via HTTP put – Posts are translated into the RFC822 format – Wrapper returns a status code indicating that the addition of data was completely correctly How can SIOC disseminated? (cont’d) • Web-based systems – Bulletin boards, weblogs, social networking sites, and so on… – Create SIOC export modules for popular open-source discussion systems – Infecting the Web Infrastructure: • During next upgrade cycle gigabytes of community data become available – Initial versions of SIOC metadata exporters created for: • Content management system (Drupal) – http://sioc-project.org/drupal • Bulletin board system (phpBB) [in progress] • Blogging system (WordPress) – http://sioc-project.org/wordpress • French blogging system (DotClear) – http://sioc-project.org/dotclear How can SIOC disseminated? (cont’d) • Sample SIOC exports from WordPress How can SIOC disseminated? (cont’d) • Mirror data in RDF store – Allowing querying of the information that sites publish in flat files – Replicate the information in a data store that can process queries – Queries are answered from the replica – The replica is updated either a crawler or original site • Native RDF store – For newly architected sites that can make use of a native RDF repository to store their data • Jena2, Sesame, Redland, and so on – Just use their APIs for importing and exporting straightforwardly! Using SIOC Data • Then, How can SIOC data be used? Source : Stefan Decker’s talk, “Towards Semantic Web 2.0 – Creating Social Semantic Information Spaces”, 2006, DERI Browsing • Navigating the SIOC Data – Use a mapping from SIOC to a data format – Use existing RDF browser Querying • Posing structural queries against the collected data – SIOC considered querying one community site in isolation until now – Queries can be routed across similar community sites into the different site management by using the infrastructure for distributing queries Querying (cont’d) • An example of SIOC querying Locating Related Information • For preparing the data in advance at creation time of a post • SIOC queries the network of community sites to find related posts when – New post is created in a community site – SIOC information is available • After the related resources is received – Community site stores resulted information using a related_to property – Information about the resources the article links to is also extracted from a post body and stored in a links_to property Conclusion • Presenting the SIOC ontology and mapping to and from other vocabularies • Providing an upgrade path that allows a gradual migration from existing systems to semantically-enabled sites • Developing a prototype SIOC exporter and browser • In the future… – Exploiting the characteristics of intra- and inter-site to guide query routing in a P2P-like environment Discussion • Some technical problems – We have to consider the types of SIOC exporter • Naver blog’s service format is differ from Tistory.com • We need to build each SIOC exporter according to service format of its original service type (whether they are all kinds of blog service or not) • In addition, it costs lots of resource while translating each crawled data from original sources into SIOC data format • At the bottom… – They said that SIOC is the one of successful case of merging Web 2.0 and Semantic Web… – SIOC project is started in Oct. 2004 • It is still being developed now – and it still do not give any attractive contributions to social community services or blog service providers practically – Where’s the problem? • • • • SIOC? Service vendors the vision of “Semantic Web 2.0”? Semantic Web?