Post on 05-Dec-2014
description
Miel Vander Sande!@miel_vds !
Publish Data as !Time consistent !
Web API !
Cultural Heritage – Open Data !
ARCHIVE & DESSIMINATE metadata or data !
Web
API
R R
API
R R
API
R R
Resource-oriented scalable & easily combined !
Linked Data, Mashups, Web applicationS
HTTP !
API
R R
API
R R
Resources’ value (state) change over time !
APIs only publish most recent state!
Resource state changes lead to inconsistenties in mashup results !
http://example.com/average-income!http://example.com/unemployment-rate!
2004
2012 InaccuRate MASHUP!
Memento
DateTime negotiation over HTTP !
Constant state over resources !
Van de Sompel et al.!http://mementoweb.org!
R TG M Original Resource! TimeGate! Memento(s)!
M M M
Memento
R TG
GET ! 200 OK!Link: URI-TG;!type=timegate!
M M M M
Memento
M M M M R TG
GET !Accept-Datetime:!
2014-05-14T00:00:00!
302 Found !Location: URI-M!
Memento
M1 M3 M4 M2
Mementos: encapsulated prior states with timestamp !
Memento
M1 M3 M4 M2
Select last valid Memento at given Datetime!
GET URI-TG !Accept-Datetime: 2014-05-15T00:00:00!
Memento
M M M M R
GET !
TG
200 OK!Link: URI-R;type=original!
Link: URI-Mn;type=next!Link: URI-Mp;type=previous !
Memento
Each API works with!
Own Archiving System !Own Storage Access !
Own File Formats !
Custom implementation required !
Memento
Publish data as !TIME CONSISTENT API
Storage! API ! Memento !
Data management!
Versioning!
Publishing Resources !
HTTP interaction !
Datetime negotiation !
DYNAMIC + GENERIC ??
PROVENANCE !Who, WHEN & WHAT
happened to my resources? !
M1 M3 M4 M2
Provenance !describes when resource values change!Was revision of Was revision of Was revision of
A2 A4 A3 A1 generated generated generated generated
PROV-O!provenance in RDF!
<Resource> prov:wasRevisionOf <Resource/M3>; prov:wasGeneratedBy :rev4.
:rev4 prov:endedAtTime "2014-06-10T14:30:00Z"^^xsd:dateTime.
<Resource/M3> prov:wasRevisionOf <Resource/M2>; prov:wasGeneratedBy :rev3.
:rev3 prov:endedAtTime "2014-05-14T14:30:00Z"^^xsd:dateTime.
Publish data as !TIME CONSISTENT API
Storage! API ! Memento !
Data management!
Versioning!
Publishing Resources !
HTTP interaction !
Datetime negotiation !
PROVENANCE
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Provenance*!
File versions !
Version Resources !
File!
File Resource!
1. Versioning & MANAGING FILES!
PROV CSV CSV-Cx CSV-Cx CSV-Cx CSV-Cx
http://git2prov.org�
Data Commits Provenance
2. CREATING THE API!POST !/api/definitions !{ “uri”: file-url, “type”: “text/csv”, “Delimiter”: “,” }
The DataTank: instant REST API for heteregeneous data !
file-url
commit-url
PROV
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2. CREATING THE API!
200 OK!Location: URI-L!
The DataTank: instant REST API for heteregeneous data !
PROV
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GIT !
2. CREATING THE API!
API ! L M M M V
Link: provenance! describes !
CSV CSV-Cx CSV-Cx CSV-Cx CSV-Cx
PROV
API !
GMP ! R TG M M M M
L PROV M M M V
GET !Link: provenance! describes !
GET ! GET !
3. GENERIC Memento PROXY
Decision Engine
GENERIC Memento PROXY
TG
PROV
GET !Accept-Datetime:!
2014-05-14T00:00:00!
N3 rules
EYE Reasoner
M
+ V
302 Found !Location: URI - M!
DeCISION LOGIC WITH SEMANTIC REASONING!EYE reasoner and N3 rules select memento !
prov:wasRevisionOf rdfs:subPropertyOf :memento.
:memento a owl:TransitiveProperty.
:request :datetime "2014-05-15T00:00:00Z"^^xsd:dateTime
DeCISION LOGIC WITH REASONING!EYE reasoner and N3 rules select the memento !
{ :request :datetime ?req_datetime. [] e:findall (?datetime { ?rev prov:endedAtTime ?datetime . (?datetime ?req_datetime) pred:dateTime- less-than-or-equal true. } ?datetime_list) .
?datetime_list e:max ?current_datetime. ?current prov:endedAtTime ?current_datetime. } => { :response :memento ?current. }.
IF prov:endedAtTime is largest prior to given ?req_datetime
THEN !Selected memento is the !?current one
DeCISION LOGIC WITH REASONING!EYE reasoner and N3 rules select the memento !
:response :memento <Resource/M1> .
:response :next-memento <Resource/M2> .
:response :last-memento <Resource> .
Publish data as !TIME CONSISTENT API
Storage! API ! Memento !
Data management!
Versioning!
Publishing Resources !
HTTP interaction !
Datetime negotiation !
DYNAMIC + GENERIC ??
Publish data as !TIME CONSISTENT API
Storage! API ! Memento !
Data management!
Versioning!
Publishing Resources !
HTTP interaction !
Datetime negotiation !
PROVENANCE
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Miel Vander Sande!@miel_vds !