A Beginner�s Guide to the Semantic Web

UKMW 2005: The future of the Digital Object: A Beginner’s Guide to the Semantic Web Mike Lowndes, Interactive Media Manager, Natural History Museum, London (Right-click or click-hold (Mac) and press k or select Speaker Notes) Contents • Web futures. • Digital objects. • The semantic web: Definitions, goals and components. • Steps along the way, short, medium and long term. • Examples from Museums. • Is it actually going to happen? • Conclusions for Museums and a call to action. Web Futures • The future web is an unknown country. Whatever we propose today, the reality will very likely be different. • Technology progresses and conceptual thought keeps playing catch-up with it. New ideas supplant old. • The future „web‟ will be as messy as the past. • So… • For Museum purposes, we should strive toward a greater signal to noise ratio. Web futures: Other Developments • Convergence – The web becomes TV-like, but remains interactive and always available. – More and deeper layers of information. – It will become optionally immersive: degrees of immersion depending on how you interact with it. • Internet 2 www.Internet2.org – Infrastructure, for massive bandwidth. • Grid computing www.gridcomputing.com – Shared processing: increasing available power when connected. – Computing power becoming a utility like electricity. – Towards instant processing of everyday tasks (in the human timeframe). Web Futures: Internet Ubiquity. • All technological devices connected. – The intelligent fridge, RFID, mobiles with GSM, GPRS, G3. – Future mobile device: operate your bank account, hifi and front door lock, turn the car heater on before you get to it – these things are not that far away. • The „web‟ is already old-school. – We don‟t yet have a simple word for the continuum between digital radio, TV, the web, mobile internet, sms and multimedia kiosk interactions, though internet technology underpins it all. – We can no longer limit our thinking to the needs of the desktop browserbased „web‟. Back to the Digital Object • Digital object. • Named Anomalocaris. • Did that help? •If we need help to make sense of many digital objects, Google etc need even more. •A digital object should include or connect to the supporting data that allows both humans and machines to understand it. •The semantic web will: –Provide standards and tools for attaching, extending and making available the „meaning‟ of digital objects. –Make the digital medium self-explaining. (right click/click-hold (Mac) for notes) What are the worst things about today’s web? • Its „manual‟ – a „pull technology‟. – Google is currently the most popular way to begin exploring a topic. – It relies on humans to link sensibly to interesting and relevant content. • Hyperlinks. They are mostly dumb. – – – – They do not explain themselves. Can you trust them? When you create them, you need to keep validating them. Searching for new links to make requires a search engine. • Metadata can improve this, but metadata is poorly used. • Answer: The semantic web Web Issues For Museums • People trust museums and their links more than others, perhaps. • But our knowledge and collections are not available easily for the public, as a single ‘collection’ relevant to their needs. • We all see this „interoperability‟ as a difficult thing. It is. • Our metadata is easy to publish, but nothing „out there‟ uses it to improve searching. • Attempts are being made (e.g. OAI-PMH- see notes) • Answer: The semantic web. (right click/click-hold (Mac) for notes) The Semantic Web Tim Berners-Lee – Visionary. Leading W3C, he‟s ahead of the game. Goal is the solution to information overload. Via global use of metadata., leading to vastly improved „browsing‟ and agents which may seem intelligent, because they can process a web that describes itself. • „Adding logic to the web‟ – If you‟re 38 and some available content is aimed at six year-olds, then its not appropriate to prioritise display (unless you‟re searching for your kids). This kind of logic is built into the semantic web. • • • • • „Turning the web into a global database‟ – Semantic web software should be able to find, sort, classify, interpret, and present relevant content in context. W3C Definition • TBL: – „The Semantic Web is an extension of the current Web in which information is given well-defined meaning, better enabling computers and people to work in cooperation.‟ • For the Web to become a truly machine-readable resource, the information it contains must be structured in a logical, comprehensible and transparent fashion. • This is the primary work required to ‘enable’ the semantic web. What the Semantic Web Will Require • DigiCULT (Themed issue 3, 2003): – Adoption of metadata standards. – The development of tools for automatic and semiautomatic multilingual knowledge mark-up. – Modelling relationships. E.g between types of metadata. – Construction of „ontologies‟ (and mappings between them). • Stay awake! (right click/click-hold (Mac) for notes) Boxes and arrows – no clouds! Context Other ontologies Maps to User query, or query generated by user behaviour User profile Maps to and is constrained by Identified ontologies Semantic Web Agent Accurate, meaningful •Answers •Actions •Views of information A digital object Associated metadata (right click/click-hold (Mac) for notes) The Building Blocks How do we get to the semantic web? XML • XML underpins the next step. • It can describe the 'data' on the web by wrapping that data in tags that explain it. – E.g.orange20 • XML is a framework. – Ad-hoc files can be created in it for specific uses, using any tags you like. – There is no need to formally describe them unless you want them to be understood outside your particular use. XML Languages for Describing Content • You can formalise a tag set written in XML by creating a „config file‟ for it, known as a Document Type Definition, or more recently, a Schema. – e.g. • Summary Metadata: Dublin Core and its derivatives. • Rich Metadata: Encoded Archival Description. • XML can also format and transform itself with XML „stylesheets‟: XSL/XLSt. • Formal XML „languages‟ for structuring, communicating and understanding data will underpin the semantic web. • “Web Services” will enable machine-to–machine communications using these XML languages. Current Semantic Web Work of W3C (2005) 1. A roadmap. Two „formal‟ technologies now part of the first generation semantic web: 2. RDF for holding the information. 3. OWL for describing relationships and inferring meaning. • There is a lot more in development… – E.g. FOAF – friend of a friend. 1. W3C Semantic Web RoadMap (right click/click-hold (Mac) for notes) 2. RDF: Resource Description Framework • W3C supports the development of the “Resource Description Framework ”. – RDF is the „official‟ current encoding format for semantic web data. • Can contain data, metadata and relationships. – E.g. Dublin Core, RSS. – Makes web resources self-describing. • RDF-S (a more recent development) – „Schema‟ provides some ontology support to RDF. 3. Ontologies - OWL • W3C supports the development of the Web Ontology Language,usually abbreviated as OWL. • What is an „ontology‟? – A dictionary defines the meaning of words. – A taxonomy or classification system describes hierarchical relationships between things but not usually other kinds of relationships. – In a faceted taxonomy things exist on more than one branch of the hierarchical „tree‟. • E.g Nature ‘contains’ Life (biology etc) and Earth (geology etc): Dinosaurs: Life > Reptiles > Dinosaurs, or Earth > Fossils > Dinosaurs – A thesaurus deals with wider relationships between words but meaning by inference only. • Ontologies join these together and can derive logic and inference. • OWL is the latest iteration of this idea. – (partly based on yet another – DAML+OIL) • It is a ‘vocabulary extension’ of RDF – not something „different‟. FenFire Ouch, my brain hurts. (right click/click-hold (Mac) for notes) Definitions and Properties of an Ontology • James Hendler: – „a set of knowledge terms, including the vocabulary, the interconnections in meaning, and some simple rules of inference and logic for some particular topic.‟ • „Standards for describing and showing relationships between data.‟ • DigiCULT: – “The most typical kind of ontology for the Web has a taxonomy and a set of „inference rules‟.” • TBL: – An ontology may express the rule "If a city code is associated with a state code, and an address uses that city code, then that address has the associated state code.” = the functionality of a database (query) and a thesaurus (meaning by context). How Will Ontologies Be Used In The Semantic Web? • Ontologies can be domain-oriented, task-oriented, application-oriented or general purpose. Also called „class taxonomies‟. • „Upper Ontologies‟ are more general and can tie more specific ones together by „mapping‟ them. • e.g. – – – – „watercolour‟ links to a definition URL. „watercolour is a type of painting.‟ „a necklace is a type of jewellery‟. „painting‟ and „jewellery‟ are both types of „art‟. • Someone needs to build these relationships. • They will be built in RDF/OWL (at least, for now). • Now, do it all again in multiple languages. Visual navigation of ontology (Sculpteur) • • Visualising RDF metadata: An aid for Museum professionals, not the public. Addis, M., et al., New Ways to Search, Navigate and Use Multimedia Museum Collections over the Web, Figure 3, in J. Trant and D. Bearman (eds.). Museums and the Web 2005: Proceedings, [CD-ROM: ISBN 1-885626-31-2] Toronto: Archives & Museum Informatics, March 31, 2005 (right click/click-hold (Mac) for notes) Boxes, arrows – and Acronyms OWL Maps to User query, or query generated by user behaviour Context Other ontologies User profile FOAF RDF-S/ OWL (CIDOCCRM) Maps to and is constrained by Identified ontology RDF Semantic Web Agent Accurate, meaningful •Answers •Actions •Views of information A digital object Associated metadata (right click/click-hold (Mac) for notes) Building blocks 2 Steps on the way to the semantic web Short Term: some current applications • Making digital resources self-describing… • RSS – – – rich site summary, making simple summary information self-describing. • Mobile devices: CC/PP. called Composite Capability/Preference Profile (CC/PP). will let cell phones and other non- standard Web clients describe their characteristics to other software and agents. • Business: XBRL. – – – – – – – – – describes/classifies content of financial statements. makes report generation easier. • FOAF Friend of a Friend. Describes people and their interests, plus network of peers. www.foaf-project.org/ • Topic Maps. A framework for creating and browsing relationships. Works within and between between systems and disciplines. Works with RDF. Human friendly; relatively easy to grasp how it works -browsers in development. (Omnigator) (right click/click-hold (Mac) for notes) Medium Term: e.g. 'smart links' As „semantic‟ content appears browsers can be modified to use it. On mouseover…. • Metadata of target. – [More information on evolution]. Author: the natural history museum. Date published: May 2005. Description: A website exploring evolution by natural selection. Audience: 12 years plus. Language: English (international). • Multiple targets. – [More information on evolution]. Link: definition of evolution. Link: evolution at the Natural History Museum. Link: evolution at the American Museum of Natural History. Link: evolution at New Scientist magazine. Definition: Evolution: part of natural history. Browse evolution. • • • These do not even need to be defined as ‘links’ – simply highlighting words could initiate the ‘semantic web browser’. Its ‘automatic for the people’. As well as ‘smart links’ more and more ‘local domains’ of knowledge will be related by their linking ontologies. (right click/click-hold (Mac) for notes) Long Term: Agents • DigiCULT: – Agents are the final „product‟ of the semantic web – automatic, even artificially intelligent software that does all your searching for you (the process of narrowing down) and much more. However, this is a very long term goal and there are many steps on the way, each of which can help. • Examples: – The agent attached to your diary automatically organises travel etc, and can change your travel tickets when you alter your diary. – The agent attached to your house automatically organises food purchasing, bill payment, lighting, heating, alarms etc. What is the cultural sector doing? We Have A Role. • Were are the holders of knowledge and authority, and can help to define the semantic web. – Thesauri owned and created by Museums could become ontologies and act as part of the backbone. • Museums are currently behind and will remain behind as other areas see competitive advantage: business, commerce, even research. • DigiCULT Thematic issue 3, 2003 – museums need to take a lead. We need to do a big project together; Standardise thesauri, develop ontologies. Examples : The CIDOC Conceptual Reference Model • A common language and extensible semantic framework to which any cultural heritage information can be mapped. The „interoperability glue‟. • Provides the „words‟ and „relationships‟ we can use to map our stuff together. • Proposed as an international standard. • Exposed in RDF already – RDF-S/OWL to follow? • http://cidoc.ics.forth.gr/ • For an introduction, download: http://www.rlg.org/en/downloads/2002metadata/gill/gill.PPT Example: Sculpteur • Several collections brought together into one place, one meta – database or portal. • Content from the V&A among others. • Visual display of relationships. • A published „ontology‟ in RDF. • Concept-based searching based on a semantic network. • Content-based searching of images and 3d models. – http://www.sculpteurweb.org/ (Browser needs downloading) Museum thesauri in Topic Maps • Ontology framework written to thesaurus standards. • Museum thesauri turned into ontologies in Topic Map format. • Topic Map browser provides a visual environment (Omnigator) for checking. • Aims to provide „meaning‟ – an authoritative reference that software can use when searching the web for Museum objects. • Can become part of the future semantic web „backbone‟. – MCG Newsletter, April 2004. Richard Light VICODI – „Visual Contextualization of Digital Content‟ • „semi-automatic creation of contextual semantic metadata for digital historical resources, by users‟. • „Visualisation of richly structured, contextualised content‟. • Interface uses historical maps and colour-coded links. • Felt to be not generally usable in hindsight by the developers but still in development. – http://www.vicodi.org/ – http://www.eurohistory.net/Index.do (right click/click-hold (Mac) for notes) VICODI - powered Finnish Museums on the Semantic Web • • • • The most ambitious and realised attempt. Uses RDF encoded Dublin Core metadata. Brings 15+ Museum collections together. Appears as a basic, text based search and browse interface – a bit like an automated Yahoo directory. • Difficult to assess as it is in Finnish, but has good critical reports from users. • A semantic web HTML generator is in development. – http://museosuomi.cs.helsinki.fi/ Finnish Museums on the Semantic Web All the right buzzwords in all the right places. (right click/click-hold (Mac) for notes) Finnish Museums on the Semantic Web Finnish Museums on the Semantic Web (right click/click-hold (Mac) for notes) Coda: Reality Check Is the semantic web the right approach to information overload? Problems with structuring knowledge • All knowledge codified? –The web will always be chaotic. • Its hard to do, not easy like the current web. • Initially it will be used by the „formal web.‟ – – – – – commerce academia b2b education institutions • The informal web (most blogs/wikis, personal pages, link sets etc) will benefit from the work, and will get tools eventually. • Consider the speed of technological advance: – by the time we get close to it, something better will come along. Nay-sayers? DigiCULT: Janneke Van Kersen, Dutch Digital Heritage Association. – “I do not believe in developing a fundamental ontology to give meaning to information on the Net. It looks to me like the 18th-century endeavour to write an encyclopaedia that contains all the knowledge in the world. I am afraid it does not work that way. A lot of knowledge, even scientific knowledge, cannot be described in a logical way. Especially in the arts a lot of “knowledge” is the result of heuristics and associative thinking.” Patel-Schneider and Siméon, Bell Labs Research. – „…there is a semantic discontinuity at the very bottom of the Semantic Web, interfering with the stated goal of the Semantic Web: If semantic languages do not respect World-Wide Web data, then how can the semantic web be an extension of the World-Wide Web at all?‟ Then it’s impossible? TBL sees the Semantic Web as based upon a whole bunch of ontologies mapped together. ‘Instead of asking machines to understand people’s language, ask people to make the extra effort’ – It is acknowledged that this is a vast and difficult thing to do. – The tools are not yet there. The consensus. • Its utopian – but the main goals are achievable. – It will be a part of the future web, but never all of it. – Any movement towards it increases the „signal to noise ratio‟ of the web. – It should and will be done where it can be. Conclusions for Museums DigiCULT : „The Semantic Web is a direction, it is like North. You go North but you never arrive and say “here it is.”‟ – Its going to be a large scale, collaborative, community thing. – Requires leadership and opportunity from the State. – We can and should make more starts now. – There are many valuable steps on the way. Further Reading • Tim Berners-Lee – BERNERS-LEE,T., J. HENDLER, O. LASSILA “The Semantic Web: A new form of Web content that is meaningful to computers will unleash a revolution of new possibilities” Scientific American, 17 May 2001. – http://www.sciam.com/article.cfm?articleID=00048144-10D2-1C7084A9809EC588EF21 • DigiCULT – Themed Issue 3: Towards a Semantic Web for Heritage Resources, May 2003. [PDF] – http://www.digicult.info/pages/themiss.php • Brian Kelly, Introduction to the Semantic Web [Powerpoint] – More examples and a good introduction to the nuts and bolts of RDF (originally for local government) – http://www.ukoln.ac.uk/web-focus/events/conferences/lga-2002/ Thank You