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Representing URI Resolution in OWL

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Alan Ruttenberg, Oct 3, 2006 HCLS F2F. Representing URI Resolution in OWL. Alan Ruttenberg (responsible for errors) Matthias Samwald. Jonathan Rees ... – PowerPoint PPT presentation

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Title: Representing URI Resolution in OWL


1
Representing URI Resolution in OWL
  • Alan Ruttenberg (responsible for errors)
  • Matthias Samwald
  • Jonathan Rees

2
What goes wrong with URLs
  • The server disappears (s)
  • The content disappears - 404 (c)
  • The content might change and you want to know and
    communicate what it used to be (d)
  • Access to the content is too slow (s)
  • Access to the content is too public (p)
  • The content is very big (b)
  • You don't know if a URI is an information
    resource or not (w)
  • You want to record and access metadata -
    information about some information resource - and
    you don't know where to get it. (m)
  • You don't know what format an information
    resource is encoded in. (f)

3
Existing proposals LSIDs
  • Authority
  • Location independence
  • Data/Metadata distinction
  • Access method independence
  • Versioning
  • (similar ARK, purl, DOI)

4
Existing proposals http-range14
  • Use http.
  • Use result code to recognize potential
    non-information resources
  • Result code 2xx information resource
  • Result code 3xx any resource, pointer to more
    information
  • Result code 4xx unknown type
  • 303 to get more information about the thing

5
Existing proposals Content negotiation
  • Agent asks for resource
  • Server responds with list of content types and
    where to get each
  • Agent chooses which to retrieve

6
Short statements
  • John Barkley
  • Identify MIME Types of URIs.
  • Identify versions of URIs
  • URIs should dereference to something, even if it
    is only documentation,e.g., rdfscomment
  • Use LSIDs

7
Short statements
  • Phil Lord
  • URIs should identify one thing only.
  • URI allocation schemes should encourage stability
    over time.
  • Resources identified by URIs should be
    checksummable.

8
Short statements
  • Matthias Samwald
  • Be careful what you are talking about - use
    separate names
  • Distinguish information resource from
    non-information resource
  • Distinguish making a query from resolution

9
Short statements
  • David Booth (Information resources/metadata)
  • http//example.org/foobar might identify a
    thing(non-information resource),
    http//example.org/foo can be used to seek
    metadata about it.
  • Dereferencing non-information resources yields a
    http 303 result code

10
Selected issues with proposed solutions
  • http-range14 - late dont know anything until
    you do the retrieval
  • Content negotion - confusion over what the thing
    is - e.g. foaf human readable document, rdf at
    same address. Try talking about the ugly font.
  • LSID - requires server deployment. Based on web
    services (slow). Unclear semantics of versions,
    metadata, data
  • No single proposal deals with all issues

11
An Alternative
  • Use the our SW tools to help solve this problem
  • Represent the information that you want to know
    about URIs in OWL.
  • Build an ontology to represent consensus/schema.
  • Take advantage of consistency checking,
    inheritence

12
Goals
  • Transparent/explicit. Contract based.
  • Adjustable
  • Extendable
  • Ontologically sound

13
Different things
  • The temperature of a patient (not an information
    resource)
  • A instrument that measures and reports
    temperature (not an information resource)
  • The record retrieved when you query the
    instrument (an information resource)
  • The record that you retrieved at a certain time
    and you copied and saved (an information resource)

but related
14
A sketch
  • Some useful distinctions
  • Top level classes
  • Some properties
  • Only about instances (not properties or classes)

15
InformationResource NotAnInformationResource
  • Information resources are conceptually Gettable
  • They might not be able to be retrieved at a
    particular time
  • They might change
  • Ask yourself Would it be possible to get the
    thing itself over a network
  • Disjoint

16
UnchangingInformationResourceEvolveableInformatio
nResource
  • UnchangingInformationResource is like LSID
    data. A promise is made that the content will
    never change.
  • EvolveableInformationResource are resources that
    might change (even if we dont want them to, e.g.
    NCBI gene records)
  • Disjoint

17
RetrievalMethod
  • A way to get an information resource.
  • Some examples
  • StandardURIRetrieval
  • TransformUriRetrieval http//genesdbs.org/entrez/7
    157 gt http//cache.ibm.com/?generetrieveidhttp
    //genesdbs.org/entrez/
  • SPARQLMethod gt http//genesdbs.org/entrez/7157
    gt
  • select ?dataFROM http//sparql.ibm.com/lifesci
    WHERE http//genesdbs.org/entrez/7157 data
    ?data
  • WebServiceMethodSupply a WSDL, name of parameter

18
RetrievalMethod (notes)
  • There may be more than one.
  • When more than one try them all in random order,
    or explicitly represent preference.
  • For company specific retrieval, add another
    RetrievalMerthod to an appropriate upper class
    (one more triple)

19
InformationResourceFormat
  • Explicitly give enough information to know what
    you will have to parse should you retrieve the
    resource (so you can choose whether or not to
    retrieve)
  • Like mime/type - BUT only the format, not the
    type (thats for defining by class)
  • RDFXML
  • RDFTurtle
  • JPEG
  • TIFF
  • HTML
  • Note Different formats of same digital thing
    should be given different names. (but they may be
    related by some property, e.g. hasOtherRepresentat
    ion)

20
Some classes of InformationResource
  • XrayImage
  • Triples (rdf statements)
  • MedicalRecord
  • VersionInformation
  • ProtocolDocumentation
  • ProvenanceDescription
  • SPARQLEndpoint
  • .
  • (ask me about metadata!)

21
Properties
  • Relate a NotInformationResource to an
    InformationResource - seeAlso, subjectOfMedicalRec
    ord, foafhomepage, biozend-data (described by
    data)

22
Properties
  • Relating an informationResource to metadata
  • previousVersion (UnchangingInformationResource)
  • hasVersionDescription
  • hasChangeDescription
  • generatedBy (not an information resource)
  • cachedDate
  • hasMD5 (UnchangingInformationResource)

23
An example
Class PartnersDigitalXray subclassOf
NeverChangingInformationResource subclassOf
DigitalXray mediaType hasValue jpegType
retrievalmethod hasValue webServiceMethod1002
http//partners.org/radiology/817277366 rdftype
PartnersDigitalXray mediaType jpegType
(inherited) retrievalmethod webServiceMethod1002
(inherited)
24
Sharing bare URIs
  • Dont, unless you have to. Generally messages
    should be a set of triples giving adequate
    information about type, resolution
  • If you do, use existing best practices to make
    them last, e.g. PURL
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