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Service composition. Roberto Lucchi joint work with Anders Friis-Christensen, Michael Lutz and Nicole Ostlaender European Commission – DG Joint Research Centre Spatial Data Infrastructure Unit Ispra, Italy. Outline. ORCHESTRA Service chaining and Service Chain Access Service Pilot - PowerPoint PPT Presentation
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Service compositionService composition
Roberto Lucchijoint work with
Anders Friis-Christensen, Michael Lutz and Nicole Ostlaender
European Commission – DG Joint Research CentreSpatial Data Infrastructure Unit
Ispra, Italy
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OutlineOutline
• ORCHESTRA
• Service chaining and Service Chain Access Service
• Pilot
• Control flow and data flow patterns
• Related issues
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ORCHESTRA – GoalsORCHESTRA – Goals
• Develop and test interoperable software architecture for risk management applications– specify interoperable risk management services – input to standardisation (OGC, ISO, CEN…)
• Role JRC–IES:– Technical supervisor – Pilot development within two application areas
(forest fires and flooding)
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ORCHESTRA pilot: Pan-European Assessment ORCHESTRA pilot: Pan-European Assessment of Natural Hazardsof Natural Hazards
• Implement distributed geo-processing for– Forest Fire Risk analysis– (Flood) Damage assessment
• by chaining existing ORCHESTRA (SOAP) services – Feature Access Service (FAS)– Map Access Service (MAS)– Processing Service (PS)
• in a new (risk specific) service executing the workflow
FAS OGC WFS
MAS OGC WMS
PS OGC WPS
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Service Chaining in ORCHESTRAService Chaining in ORCHESTRA
• ISO 19119 Opaque chaining (aggregate services)– Hide the business logic– Service chain instance functionalities can be re-used
• Service chain descriptions based on BPEL• Usage of the Service Chain Access Service (SCAS) for
– Managing service chain descriptions – Deploying the service chain instances in ORCHESTRA Service
Networks• SCAS provides a means to:
– getServiceChain: Get a service chain description – createServiceChain: Create a new service chain instance based on a
chain description– deleteServiceChain: Delete service chain instances– getCapabilities
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Register the createdservice chain instance
CreateServiceChain request• Chain Description (M) : MyChain• Catalogue endpoint (O) : CatUrl
MyChain
Catalogue
SCAS client
SCAS
MyChain Workflow Description
Height Difference
Store
Zonal Rating
FFRADA
<entry …><entry …><entry …><entry …>
<entry …><entry …><entry …><entry …>
Deploy
ORCHESTRA Services Network
<entry …>
SCAS: Creating new service chainsSCAS: Creating new service chains
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SCAS: get service chain descriptionSCAS: get service chain description
• The operation getServiceChain (ID) provides MetaInformation on the chain and a link to the service chain description
getServiceChain Sample response
• Requesting existing service chain descriptions can be used to:– Re-deploy in different ORCHESTRA service networks– Modify existing workflows (use new services, different techniques)
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ScenarioScenario- Forest Fires -- Forest Fires -
Pilot Application – Thematic FocusPilot Application – Thematic Focus
• Assessing natural hazards and related risks
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Pilot Application – Requirement AnalysisPilot Application – Requirement Analysis• End users: Domain experts in the context of forest fires
conducting policy support towards various EC DGs• Functionalities:
– Interoperable access to heterogeneous MS fire records– Harmonisation of heterogeneous data into a common schema – Flexible and distributed Forest Fire Hazard and Risk mapping
• Measures– Forest fire frequency: number of forest
fires aggregated by administrative unit– Forest fire density: forest fire
frequency normalised by area– Forest fire risk: forest fire density
classified into risk classes
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cd Data Model
ForestFireRegistration_Common
+ fireID: char+ dateAl: char+ timeAl: char+ timeIn: char+ dateIn: char+ dateEx: char+ timeEx: char+ codeCom: char+ nuts3: char+ nameCom: char+ tba: char+ fba: char+ nfba: char+ cause: char
Pilot Application – Conceptual LevelPilot Application – Conceptual Level1. Access
– Fire records from EU Member States– Schema mapping
2. Spatial and temporal aggregation– Based on Administrative Units– Or based on European Grid
3. Analysis – Fire frequency – Fire density– Fire risk classes
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Distributed Geoprocessing – ApproachDistributed Geoprocessing – Approach
• Identify the processing tasks required to produce the requested analysis information
• Define workflows producing the required information
• Provide workflows execution as OT-Risk-Specific Services– implemented using opaque chaining (via BPEL)– the client applications use one single service
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Distributed Geoprocessing – Processing TasksDistributed Geoprocessing – Processing Tasks
• Forest Fire Frequency– Spatial Join of Forest Fire Points with NUTS polygons– Counting joined points per NUTS polygon
Join and Aggregation service
• Forest Fire Density– Normalizing Forest Fire Frequency by area of NUTS polygons
Normalisation service
• Forest Fire Risk– Classifying risk based on forest fire density per NUTS polygon into
risk classes
Classification service
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(1) retrieve forestfire features
(2) retrieve admin.unit features
(3) aggregate forestfire features
by admin. units
(4) normalisefeatures by area
(5) classify features
(6) render featuresin a map
MS2 forest fireregistration
FAS-X
Mapping Rules toCommon Schema
uses
MS1 forest fireregistration
accesses
Administrative units
FAS
accesses
Join & Aggregation
Service
Classification Service
Processing Services
ClassificationRules
uses
Normalisation Service
MAS
SymbologyRules
uses
PEUNHA Client
(0) provide execution parameters
Forest Fire Risk
Assessment
MAS = Map Access Service
FAS = Feature Access Service
FAS-X = Translating FAS
Client
OA Info-Structure Service
OT Support Service
OT Risk Specific Service
Distributed Geoprocessing in the Pilot ApplicationDistributed Geoprocessing in the Pilot Application
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Forest Fire Risk Assessment ServiceForest Fire Risk Assessment Service
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Control and data flow patternsControl and data flow patterns• We also invetigated different chaining patterns and data
passing modalities
Centralized control flow data passed by value
Cascaded control flow(e.g. WPS)
Centralized control flow and data passed by value =separation of control and data flow BPEL + storage functionalities
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Final remarks and open issuesFinal remarks and open issues
• No standard service chain interface– High flexibility, but complicates
• clients development• service chain re-usability (and discovery)
• Service chains conformance – getCapabilities: is it mandatory?
• What kind of data reference mechanism?– URL
• WPS and WCS 1.1 can store results and return a URL – getResourceByID (OWS Common 1.1.0)
• Alternative interaction modalities– Asynchronous invocation of service chains
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Extra slidesExtra slides
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Forest FireRisk Analysis
Damageassessment
The ORCHESTRA Service Types and The ORCHESTRA Service Types and TaxonomyTaxonomy
OT support service
OA support service
OA info-structure service
OT risk specific services
Catalogue FASMAS
PSMap AlgebraPS
Classification
PSJoin & Aggreg.
FAS OGC WFSMAS OGC WMSPS OGC WPS
Obtained by chaining ORCHESTRA services
SCAS
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