OGC spet 2010 Meta-propagation of uncertainties within workflows
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Transcript of OGC spet 2010 Meta-propagation of uncertainties within workflows
®
© 2010 Open Geospatial Consortium, Inc.
Workflow Uncertainty using a Metamodel Framework and Metadata for Data and
ProcessesOGC Technical Committee
September 20-24, 2010
Toulouse, France
Didier G Leibovici and Amir Pourabdollah
Centre for Geospatial Science
University of Nottingham
OGC®
© 2010 Open Geospatial Consortium, Inc. 2
outline
• integrated modelling /scientific workflowmodel building / reusing / user’s perspective /rescaling / quality assessment
• uncertainty / sensitivity analyses for workflowserror propagation / uncertainty analysis / emulator (“metamodelling”) / use of metadata
• metadata for data and for processes quality metadata / UncertML / quality principles & measures for processes
• metamodel for workflows notation/ encoding/ enrichment
• towards Web Workflow Service? WPS / WWS / requirements for workflow assessment
FP7 European project
OGC®
OGC initiatives related to workflows
• OWS-5 http://www.opengeospatial.org/projects/initiatives/ows-5
conflation workflow and SWE workflow
• OWS-6 http://www.opengeospatial.org/projects/initiatives/ows-6GeoProcessing Workflow, Decision Support Service
http://www.opengeospatial.org/pub/www/ows6/web_files/ows6.html
© 2010 Open Geospatial Consortium, Inc. 3
OGC®
OGC OWS-5 conflation workflow
© 2010 Open Geospatial Consortium, Inc. 4
OGC®
OGC OWS-6 landslide sensor geoprocessingworkflow
© 2010 Open Geospatial Consortium, Inc. 5
OGC®
Debris flow operational scenario
OGC®
integrated modelling/ scientific workflow
© 2010 Open Geospatial Consortium, Inc. 7
model building
reusing
user’s perspective
multidiscipline
rescaling
quality assessment
uncertainties
OGC®
integrated modelling/ scientific workflow
• representation BPMN
© 2010 Open Geospatial Consortium, Inc. 8
toy example:greenness model
Data3= P1(Data1, Data2)
Data3= P1’ (Data1, Data2, Data7)Data6= P2(Data3, Data4, Data5)
P1’
D7
OGC®
uncertainty / accuracy /sensitivity
© 2010 Open Geospatial Consortium, Inc. 9
OGC®
© 2010 Open Geospatial Consortium, Inc. 10
OGC®
uncertainty / accuracy /sensitivity
© 2010 Open Geospatial Consortium, Inc. 11
OGC®
uncertainty / accuracy /sensitivity
• error propagation (via the model)
– variables interaction
– spatial dependence of uncertainties
© 2010 Open Geospatial Consortium, Inc. 12
sensitivity and uncertainty analysis
sampling design and model building
sampling design and propagation
OGC®
uncertainty / accuracy /sensitivity
• uncertainty analysis what is the output uncertainty?
• and sensitivity analysis where output uncertainty comes from?
© 2010 Open Geospatial Consortium, Inc. 13
1. uses quality metadata about inputs (distribution, variance, ...)
2. sampling design accordingly
3. look at output distribution, variance, ... and compare with inputs
A. using the model
B. using an emulator (see UncertWeb project)
C. can we do a simple estimation without 2 and 3?
for each atomic process
Workflow level
OGC®
propagating thematic uncertainty
© 2010 Open Geospatial Consortium, Inc. 14
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variance
OGC®
propagating thematic uncertainty
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• is in the “tolerance” of according to ? ~
• If then
• if
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Sensitivityinformation
OGC®
propagating thematic uncertainty
© 2010 Open Geospatial Consortium, Inc. 16
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Need more thanSensitivityInformation
Need a kind of meta-sensitivityi.e. for various samplingVariancesa variance transfer function
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OGC®
metadata for data and for processes
• ISO standards (data and services)
19115, 19113, 19114, 19135, 19138,19119, (19139)
• UncertML (OGC discussion paper)
encoding uncertainty measures
© 2010 Open Geospatial Consortium, Inc. 17
ISO 19113 - Quality principles, ISO 19114- Quality evaluation procedures, ISO 19115-Metadata, ISO - 19138 - Data quality measures and ISO - 19135 Registration,
OGC®
metadata for data
© 2010 Open Geospatial Consortium, Inc. 18
Table 1: Data quality elements and data quality sub-elements with definitions (ISO 19113)
OGC®
metadata for data
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OGC®
metadata for processes (proposal)
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OGC®
metadata for processes (proposal)
© 2010 Open Geospatial Consortium, Inc. 21
OGC®
© 2010 Open Geospatial Consortium, Inc. 22
Metadata for processes / basic measures
OGC®
© 2010 Open Geospatial Consortium, Inc. 23
Metadata for processes / basic measures
• encoding using the same structure as in
ISO19115/ISO19139 for data quality
DQ_element PQ_element
• registration of measures ISO19135
PQ_ConflationInformationLoss, PQ_ThematicClassificationPropagation, PQ_QuantitativeAttributePropagation PQ_ConceptualSemanticConformance, PQ_DomainConsistency, PQ_TopologicalPreservation
OGC®
Metadata workflow quality / metadata propagation
© 2010 Open Geospatial Consortium, Inc. 24
Dynamic Metadatae.g -discrepancy of scales (data chosen vs expected input)
-Capitalising uses:dynamic alsoby web 2.0
-parameter choices ”
model building
reusing
user’s perspective
multidiscipline
rescaling
quality assessment
OGC®
metamodel for workflows
• representing / storing & navigate / execute• notation encoding enrichment engine
BPMN XPDL (extensions) XPDL or BPEL engine
PNML (Petri-Nets)
• enrichment with metadata (quality element)• enrichment with semantic related to quality (tags)
© 2010 Open Geospatial Consortium, Inc. 25
e.g greenery / greenness model
OGC®
XPDL 2.1 process meta-model
© 2010 Open Geospatial Consortium, Inc. 26attached with quality metadata
OGC®
XPDL 2.1 linking with BPMN
© 2010 Open Geospatial Consortium, Inc. 27
attached with quality metadata
OGC®
Extended attributes
• Without namespace
• With namespace
© 2010 Open Geospatial Consortium, Inc. 28
OGC®
BPMN/XPDL Example
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Data3= P1(Data1, Data2)
OGC®
BPMN/XPDL Example – Step 2
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Data3= P1(Data1, Data2)Data6= P2(Data3, Data4, Data5)
OGC®
BPMN/XPDL Example – Step 3
© 2010 Open Geospatial Consortium, Inc. 31
Data3= P1’ (Data1, Data2, Data7)Data6= P2(Data3, Data4, Data5)
‘
OGC®
towards Web Workflow Service?
• needs to easily
combine /assess / refine web data/process services
• in a “WPS” fashion (WPS are atomic Workflows)
• and other things: validation using PNML
© 2010 Open Geospatial Consortium, Inc. 32
OGC®
towards Web Workflow Service?
• WPS executing a worklfow
see OWS-5 6 (“hard-coded” and / or using a BPEL engine)
• WPS acting alike a workflow service WPS GetCapabilities:
. specific operations stored as available processes (Op)
. list of the workflows processes (Wkf)
the principle is the Ops informed on a Wkf by returning an enriched XPDL file representing the workflow
• WWS the “WPS acting” has unbalanced intrinsic properties of the existing processes living in the WPS
© 2010 Open Geospatial Consortium, Inc. 33
OGC®
towards Web Workflow Service?
• WPS acting alike a workflow service WPS GetCapabilities:
. specific operations stored as available processes (Op)
. list of the workflows processes (Wkf) the principle is the Ops informed on a Wkf by returning an enriched XPDL file
representing the workflow
1. OpShow Id_Wkf returns the XPDL (enriched) of a Wkf
2. OpSet data/processes (modifiable entries of Wkf) returns the updated XPDL file with the updated metadata (particularly propagated
metadata)
3. OpExecute, same as OpSet but runs the Wkf as an“aggregated process”, returns an XPDL containing as well the links for the outputs.
4. OpStatus returns the status per node of the Wkf in an XPDL file
© 2010 Open Geospatial Consortium, Inc. 34
OGC®
towards Web Workflow Service?
• WWS• GetCapabilities OGC generic request• DescribeWorkflow request to retrieve the definition of a workflow in a number of
standard formats, in which XPDL is the primary choice. It corresponds to OpShow.
• DefineWorkflow like OpSet allowing to set/modify a workflow (fixed workflow witih user’s input, partially modifiable workflow with user’s inputs and swaps of internal processes or data, or user’s workflow)
• ExecuteWorkflow as OpExecute launch the execution in “instant” or “delayed” mode, as in WPS and requests the execution status as XPDL or “other workflow format”.
Parameters to manage the
- different levels of aggregation/hierarchy (e.g. an erosion model may have precipitation model and a run-off model (among other sub-models).
- uncomplete but published conceptual workflows (collaborations)
© 2010 Open Geospatial Consortium, Inc. 35
OGC®
© 2010 Open Geospatial Consortium, Inc. 36
summary
• integrated modelling /scientific workflowmodel building / reusing / user’s perspective /rescaling / quality assessment
• uncertainty / sensitivity analyses for workflowserror propagation / uncertainty analysis / emulator (“metamodelling”) / use of metadata
• metadata for data and for processes quality metadata / UncertML / quality principles & measures for processes
• metamodel for workflows notation/ encoding/ enrichment
• towards Web Workflow Service? WPS / WWS / requirements for workflow assessment
FP7 European project