1. doc.: IEEE 802.19-01/0169r0 Submission Joe Kwak (InterDigital) Slide 1 November 2010 Slide 1 Overview of Resource Description Framework (RFD/XML) Date: 2010-11-11 Authors:

2. doc.: IEEE 802.19-01/0169r0 Submission Joe Kwak (InterDigital) Slide 2 Outline Basic concept: descriptive statement triple RDF/XML representation RDF capablilities: containers, collections, reification RDF Schema defines application vocabularies 802.21 example: RDF Schema for Information Service References

3. doc.: IEEE 802.19-01/0169r0 Submission Joe Kwak (InterDigital) Slide 3 Descriptive Statement TRIPLE: Subject | Predicate RDF GRAPH what | | value Truck | color | red created to describe web resources http://www.example.org/index.html has a creator whose value is John Smith RDF in XML of URIs. property attribute characteristic

4. doc.: IEEE 802.19-01/0169r0 Submission Joe Kwak (InterDigital) Slide 4 RDF/XML Representation XML qualified names (Qnames) used for RDF shorthand. Common xmlns (xml namespace) prefixes: prefix rdf:, namespace URI: http://www.w3.org/1999/02/22-rdf-syntax-ns# prefix rdfs:, namespace URI: http://www.w3.org/2000/01/rdf-schema# prefix dc:, namespace URI: http://purl.org/dc/elements/1.1/ prefix owl:, namespace URI: http://www.w3.org/2002/07/owl# prefix xsd:, namespace URI: http://www.w3.org/2001/XMLSchema# prefix ex:, namespace URI: http://www.example.org/ prefix exstaff:, namespace URI: http://www.example.org/staffid/ Same statement using XML prefixes: ex:index.html dc:creator exstaff:85740.

5. doc.: IEEE 802.19-01/0169r0 Submission Joe Kwak (InterDigital) Slide 5 Compound Statements and Blank Nodes

6. doc.: IEEE 802.19-01/0169r0 Submission Joe Kwak (InterDigital) Slide 6 Typed Literals Default literal is string of ascii for URIs RDF Schema defines many standard datatypes Online library is commonly referenced DataTypes defined in library at http://www.w3.org/2001/XMLSchema http://www.w3.org/2001/XMLSchema "value"^^

7. doc.: IEEE 802.19-01/0169r0 Submission Joe Kwak (InterDigital) Slide 7 DataTypes defined at http://www.w3.org/2001/XMLSchema

8. doc.: IEEE 802.19-01/0169r0 Submission Joe Kwak (InterDigital) Slide 8 RDF statements in XML Triple to XML equivalent:

9. doc.: IEEE 802.19-01/0169r0 Submission Joe Kwak (InterDigital) Slide 9 More Complex RDF/XML

10. doc.: IEEE 802.19-01/0169r0 Submission Joe Kwak (InterDigital) Slide 10 RDF Containers Bag: items in no significant order Seq:: items sequenced in a required order –Bag and Seq are semantically identical in XML with -  –Application layer needs to interpret order as significant for sequence only Alt: a set of alternative items "one of the below".

11. doc.: IEEE 802.19-01/0169r0 Submission Joe Kwak (InterDigital) Slide 11 Collection uses property concept of "first", "rest" and defines the null node to delimit list. Collections are closed containers whereas bags and sequences are open. Collection is a closed linked list

12. doc.: IEEE 802.19-01/0169r0 Submission Joe Kwak (InterDigital) Slide 12 Reification permits RDF syntax to be applied to RDF statements. Description of the Description. RDF triple: RDF description of the above RDF statement Useful for provenance descriptors: Created By, Creation Date, Version #etc –These are properties about the code itself –Description NOT about the objects identified and described in the code. RDF Reification – making the language a thing

13. doc.: IEEE 802.19-01/0169r0 Submission Joe Kwak (InterDigital) Slide 13 RDF permits "Literal" type for XML strings as values In this example, the value for the book title is an XML string: "" <br /> Element Considered Harmful. "" Note that the string is interpreted as XML and not simply as ascii.

14. doc.: IEEE 802.19-01/0169r0 Submission Joe Kwak (InterDigital) Slide 14 RDF Schemas A Schema is a particular use of rdf_class and rdf_property to define particular terms useful for a particular application The defined terms are called a VOCABULARY for this RDF application. The property relationships among the classes are meaningful. The datatype definitions here are an example of a schema.

15. doc.: IEEE 802.19-01/0169r0 Submission Joe Kwak (InterDigital) Slide 15 Customized Schemas are Useful Custom schema to describe

16. doc.: IEEE 802.19-01/0169r0 Submission Joe Kwak (InterDigital) Slide 16 Custom Vehicle Schema in Triples

17. doc.: IEEE 802.19-01/0169r0 Submission Joe Kwak (InterDigital) Slide 17 Custom Vehicle Schema in RDF/XML h

18. doc.: IEEE 802.19-01/0169r0 Submission Joe Kwak (InterDigital) Slide 18 Properties of RDF_Properties RDF language emphasis and some capabilities differ from object oriented languages (OOL). RDF is a description oriented language (DOL). In OOL, objects are type classed and they have properties. In DOL, properties have properties and may be abstractly defined. Properties have Range and Domain. has Domain of OBJECT Value Property has Range of

19. doc.: IEEE 802.19-01/0169r0 Submission Joe Kwak (InterDigital) Slide 19 Examples Range Ranges can also be explicit (0..255) Domain In a way these RDF statements treat properties like objects

20. doc.: IEEE 802.19-01/0169r0 Submission Joe Kwak (InterDigital) Slide 20 Using EPRI's CIM/XML Schema:

21. doc.: IEEE 802.19-01/0169r0 Submission Joe Kwak (InterDigital) Slide 21 Issues for 19.1 Utility of language for describing message structures Ease of use and readability of language for message structures. ASN.1 and RDF/XML share most, if not all, features. Extensibility is key for ASN.1 vs RDF/XML decision. ASN.1 is tightly structured and requires use of "…" placement to permit extensibility. RDF allows open ended class and property extensions. There is no "…." construct within RDF. IN PRACTICE, we would like to know the shortcomings of both approaches.

22. doc.: IEEE 802.19-01/0169r0 Submission Joe Kwak (InterDigital) Slide 22 Quick look at 802 standards 802.11 MIB in ASN.1 802.21 Information Service Schema in RDF/XML

23. doc.: IEEE 802.19-01/0169r0 Submission Joe Kwak (InterDigital) Slide 23 References RDF Primer: http://www.w3.org/TR/2004/REC-rdf- primer-20040210/#xmlliteralshttp://www.w3.org/TR/2004/REC-rdf- primer-20040210/#xmlliterals RDF Vocabulary Schema: http://www.w3.org/TR/rdf- schema/#ch_domainrangehttp://www.w3.org/TR/rdf- schema/#ch_domainrange RDF/XML Schema: http://www.w3.org/TR/xmlschema-1/ and http://www.w3.org/TR/xmlschema-2 http://www.w3.org/TR/xmlschema-1/ http://www.w3.org/TR/xmlschema-2 Many many others branch out of the above references.

24. doc.: IEEE 802.19-01/0169r0 Submission Joe Kwak (InterDigital) Slide 24 Discussion