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LOM = Words / RDF = Grammar? Nahum Korda. “One Standard for All: Why We Don't Want It, Why We Don't Need It” o Paraphrase from a presentation by Stephen.

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Presentation on theme: "LOM = Words / RDF = Grammar? Nahum Korda. “One Standard for All: Why We Don't Want It, Why We Don't Need It” o Paraphrase from a presentation by Stephen."— Presentation transcript:

1 LOM = Words / RDF = Grammar? Nahum Korda

2 “One Standard for All: Why We Don't Want It, Why We Don't Need It” o Paraphrase from a presentation by Stephen Downes (Researcher at National Research Council, Alberta, Canada) o Presentation delivered at the Athabasca University's Edmonton office o The original argument: RDF is better because it is not restricted vocabulary (like LOM)

3 Semantic Web and Learning Objects o Could LOM be formulated (presented) in RDF? o Cold LOM be integrated with the Semantic Web? o How useful is Semantic Web for LOM?

4 Semantic Web o What is Semantic Web? o What is RDF and how is it related to XML? o What are ontologies? o Demonstration

5 World Wide Web o Markup Languages (HTML primarily) o Meta-information (tags) o Links to other files o Global hyperlinked environment

6 New Concept of Document o Not a single file o A set of related hyperlinked files Content in various formats Formatting information Scripts and runtime applications

7 New Concept of Document Script to scroll news feeds XML from news feeds database Graphic files XML from directory XSL file with formatting information Flash from banner exchange database

8 New Concept of Document o A single focal point for representing all the relevant information from a wide variety of information resources o Different readability No reading order Information cannot be provided chronologically Information must be simultaneously available

9 Semantic Web o Additional layers of information Lexical definitions Links to other relevant documents Links to relevant people

10 Semantic Web o What is Semantic Web? o What is RDF and how is it related to XML? o What are ontologies? o Demonstration

11 Semantic Web o Generate these layers automatically o Allow software agents to manipulate this information

12 Resource Description Framework o Not just machine readable information o Also machine understandable information

13 Resource Description Framework Ora Lassila Ora's Home Page

14 Resource Description Framework o Subject o Predicate o Object

15 Resource Description Framework Ora Lassila is the creator of the resource http://www.w3.org/Home/Lassila.

16 Resource Description Framework Subject (Resource) http://www.w3.org/Home/Lassila Predicate (Property) Creator Object (literal) "Ora Lassila"

17 Resource Description Framework

18 Semantic Web o What is Semantic Web? o What is RDF and how is it related to XML? o What are ontologies? o Demonstration

19 Ontology o System of concepts and relations between them: Table [is piece of] furniture Arm [is part of] body Japan [is located in] East Asia o A method for storing and representing knowledge

20 Ontology

21 Semantic Web o Software applications can utilize meta- information for: Annotations Automatic summarization Hyperlinking Filtering

22 Notations for Logic oConceptual Graph Interchange Form (CGIF) [Go: *x] [Person: 'John' *y] [City: 'Boston' *z] [Bus: *w] (Agnt ?x ?y) (Dest ?x ?z) (Inst ?x ?w) oKnowledge Interchange Format (KIF) (exists ((?x Go) (?y Person) (?z City) (?w Bus)) (and (Name ?y 'John) (Name ?z 'Boston) (Agnt ?x ?y) (Dest ?x ?z) (Inst ?x ?w)))

23 RDF and Ontologies o DARPA Agent Markup Language (DAML) o Ontology Interchange Language (OIL) o An extension to XML and RDF

24 DAML+OIL BigFoots (BigFeet?) are exactly those persons whose shosize is over12.

25 Problems with Ontologies o Development and maintenance of ontologies is extremely complex and resource consuming o A useful ontology is domain specific and many various ontologies need to be developed in order to cover a variety of possible interests o Ontologies suffer from problems related to the intrinsic complexity

26 Intrinsic Complexity o Concepts in ontologies are often highly ambiguous o Ontologies must often handle multi-lingual document corpora o Criteria for defining interrelationships are typically highly inconsistent

27 Month in Calendar Historical Event Imaginary Naval Vessel Ambiguity oWeather in October is unstable. oRed October was one of the most important historical events in the 20 th Century. oThis was the first time that American military personnel came aboard Red October.

28 Multilingualism

29 Inconsistency EllipseCircle is a subtype of Mathematical Ontology EllipseCircle is a subclass of Object-Oriented Programming Language

30 Automated Idiomatic Representation o Words are not mathematical variables o Meaning is generated on the pragmatic (contextual) level – not semantic! o The meaning of a word is its use in the language. (Ludwig Wittgenstein, Philosophical Investigations, 43)

31 Automated Idiomatic Representation

32 Semantic Web o What is Semantic Web? o What is RDF and how is it related to XML? o What are ontologies? o Demonstration

33 Loads of Buzz – Little to Show oDublin Core Metadata - DC 15 core metadata categories can be expressed in RDF in web pagesDublin Core Metadata oMusicBrains metadata initiative - storing and exchanging metadata related to digital audio and video tracks oELSST thesaurus - EU thesaurus project drafted RDF format for ISO multilingual thesauri standard and the ELSST multi- lingual thesaurus of social science terms encoded in RDFELSST thesaurus

34 Loads of Buzz – Little to Show oAnnotea and Mozilla support RDF annotation servers that allow users to annotate web pagesAnnotea Mozilla oOpen Directory Project (DMOZ) - a hand crafted web directory that uses RDF to store the details of web sitesDMOZ

35 Semantic Web and Learning Objects o Could LOM be formulated (presented) in RDF? o Cold LOM be integrated with the Semantic Web? o How useful is Semantic Web for LOM?

36 How useful is Semantic Web for LOM? o Discovery Search more efficiently Apply automation to information retrieval o Interoperability Automate reusability Bridge multilingualism

37 Cold LOM be integrated with the SW? o Restricted vocabulary necessary in order to make it interoperable o Restricted vocabulary imposes severe limitations to expressibility

38 Restricted Vocabulary - Necessity o[Go: *x] [Person: 'John' *y] [City: 'Boston' *z] [Bus: *w] (Agnt ?x ?y) (Dest ?x ?z) (Inst ?x ?w) o[Go: *x] [Person: 'John' *y] [City: 'Boston' *z] [Bus: *w] (Actr ?x ?y) (Dest ?x ?z) (Inst ?x ?w) oAgnt = Actr ? oAgnt ⊂ Actr ? oAgnt ⊃ Actr ? oAgnt ⋂ Actr ?

39 Restricted Vocabulary - Limitation DE PROFUNDIS There is a stubble field on which a black rain falls. There is a tree which, brown, stands lonely here. There is a hissing wind which haunts deserted huts - how sad this evening. Past the village pond the gentle orphan still gathers scanty ears of corn. Golden and round her eyes are gazing in the dusk and her lap awaits the heavenly bridegroom. Returning home shepherds found the sweet body decayed in the bramble bush. A shade I am remote from somber hamlets. The silence of God I drank from the woodland well. On my forehead cold metal forms. Spiders look for my heart. There is a light that fails in my mouth. At night I found myself upon a heath, thick with garbage and the dust of stars. In the hazel copse crystal angels have sounded once more. Georg Trakl (1887-1914)

40 Restricted Vocabulary - Limitation DE PROFUNDIS There is a stubble field on which a black rain falls. There is a tree which, brown, stands lonely here. There is a hissing wind which haunts deserted huts - how sad this evening. Past the village pond the gentle orphan still gathers scanty ears of corn. Golden and round her eyes are gazing in the dusk and her lap awaits the heavenly bridegroom. Returning home shepherds found the sweet body decayed in the bramble bush. A shade I am remote from somber hamlets. The silence of God I drank from the woodland well. On my forehead cold metal forms. Spiders look for my heart. There is a light that fails in my mouth. At night I found myself upon a heath, thick with garbage and the dust of stars. In the hazel copse crystal angels have sounded once more. Georg Trakl (1887-1914)

41 Language o Words are not mathematical variables o Meaning is generated on the pragmatic (contextual) level – not semantic? o The meaning of a word is its use in the language. (Ludwig Wittgenstein, Philosophical Investigations, 43)

42 Could LOM be formulated in RDF? o Sure – everything can be (somehow) formulated in RDF. o Could LOM be effectively/usefully formulated in RDF? o Only if the “restricted vocabulary conflict” is successfully solved o This is however true of every Semantic Web application

43 Thank You Nahum Korda


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