GRDDL can also be used to glean RDF from plain vanilla XML data.
Merge with other RDF
e.g. data with data published on the Web in HTML
i.e. XHTML+GRDDL
Rember the magic trick: GRDDL transformations may be indirectly
linked from namespace documents
namespace document may be RDF, HTML, XML Schema, etc.
Health Care Example
Kayode wants to query clinical data
Kayode wants to write software components which can extract RDF descriptions from XML HL7 CDA documents transmitted from various devices in a healthcare system using a clinical ontology so that he can merge together clinical reports and use inferences to detect possible problems.
Getting RDF out of XML: Before
HL7 CDA: an XML vocabulary for use in clinical data
RDF browser acts as GRDDL-aware agent and finds mash-up-ready data.
RDF Calendar on a timeline
RDF Calendar on a timeline
Calendar mash-up:
Travel schedule on a map
Travel schedule on a map:
One Event in Particular
You are here ;-)
Linked Data Principles
Everything should have a URI: All entities of
interest should be identified by URIs.
Follow Your Nose Principle: URIs should be
dereference-able, meaning that an application can look up
a URI over the HTTP protocol and retrieve RDF data.
Use standard formats: Data should be provided
using the RDF/XML or
Turtle
syntax. If data is embedded using a format like Microformats ,
then these documents should include links to automatically
extract RDF data from them, ala GRDDL.
Link Your Data: Resource descriptions should
contain links to related information in the form of
dereference-able URIs within RDF statements and rdfs:seeAlso
links.
For each triple pattern, the library executes the following
algorithm:
look up URIs that appear in the triple pattern. Add
retrieved graphs to the local graph set.
look up any URI y where the graph set includes
the triple { x rdfs:seeAlso y } and x is a
URI from the triple pattern. Add retrieved graphs to the
local graph set.
match the triple pattern against all graphs in the local
graph set.
for each triple that matches the triple pattern
look up all new URIs that appear in the triple. Add
retrieved graphs to the local graph set.
look up any new URI y where the graph set
includes the triple { x rdfs:seeAlso y } and
x is a URI from a matching triple. Add retrieved
graphs to the local graph set.
match the triple pattern against all newly retrieved
graphs.
repeat step 4 and 5 until the maximum number of retrieval
steps or the timeout is reached.
The Future of GRDDL
Can we convince microformat creators and vocabulary
creators to add GRDDL transformations?
Can people use XHTML?
Can people add the GRDDL transforms?
Can we get profile URIs working for
Or do we have to hack this?
RDFa versus Microformats: Will RDFa overtake
microformats?
Advantage: RDFa uses a microformat-style to
encode entire URIs and allowing you to put up any
arbtirary RDF data...but still in early stages.
Disadvantage?
Will microformats continue spreading like
wildfire?
What sort of services will take advantage of
microformats and RDF?
