Transcript workshop_cvp_engvp

Computational Viewpoint
“How the pieces fit together”
Rob Atkinson
Social Change Online
“Functional Decomposition”
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Components
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What functions are needed
Independent of technology, and where deployed
Interfaces
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Protocols
Query Model
Response Model
Encodings
Service Oriented Architectures
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Components are seen as services available across
a network
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No code-transfer at run-time
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Predictable interfaces
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SEEGrid needs Open interfaces
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Two models:
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Request/Response (REST)
Create Virtual Object, Run, Notify (WSRF)
Common semantic challenges
SEEGrid Profiles
Ontology (OWL)
Content classified by
Interfaces
View)
OGC Web(Layered
Services
(WFS, WCS)
Viewed As
Service Chains
(BPEL4WS?)
Domain Model
(GML
Application Schema)
Describes
Stateful Resource
Handling (WSRF)
Messaging (SOAP)
HTTP
Service Binding
Metadata
(WSDL)
GML
XML-Schema
XML
TCP/IP
Protocol Stack
Content
Interoperability
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Network Protocol Interoperability allows basic communications
between components.
Standard Interface Specifications allow client applications to
execute procedures on remote systems.
Data Transport Interoperability allows transparent access to
data, the sharing of spatial databases and other services
regardless of the proprietary data storage format.
Semantic Interoperability refers to applications interpreting data
consistently in the same manner in order to provide the
intended representation of the data.
Ontology
Feature
Type
Catalog
Service
Metadata
Dataset
Metadata
Persistent
Bindings
Notional
Architecture
Registry
publish
find
Client
Applications
bind
Model
Management
Services
Processing
Services
Services
Data Access Services
Features
Coverages
Real-time
data
Models
Dataset
Metadata
Feature
Service
Dictionaries
Type
Content
StandardsMetadata
Catalog
Common register of
custodial
arrangements
Persistent
Bindings
Styling (symbology, report formats etc)
Query templates (e.g. Data Products)
Workflows
If I have a PDF
Registry
If I am a
open it with
drillhole show
Acrobat
publish
Notify
when
me as me
a colour
findIUGS Rock Types
tenements
Show me tenements
coded cross
Address
become
that will become
Species Taxonomy
section
available
Model
soon
Drillhole Address available
Geocoder
Processing
Notional
Architecture
Client
Applications
bind
Management
Services
Tenements
Services
Drillhole Database
Services
Transport Route
Route Planner
Tenements
WMS
Data Access
Services
Features
Coverages
Real-time
data
Models
Adoption of Standards Suites
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ISO 19000
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OGC (Implementation)
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W3C – XML, Semantics
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WSRF – Web Services oriented GRID computing
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W3C Web services via OGC and WSRF!
Grid and Web Services
Grid
Started
far apart
in apps
& tech
Have been
converging
WSRF
Web
The definition of WSRF means that Grid and Web
communities can move forward on a common base
Engineering Viewpoint
“Who does what if this is to work”
GRID Infrastructures
Constraints and Design Goals
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No solution (yet) for what best goes where
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So design to allow components to be deployed
anywhere
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Some components need to be authoritative for
interoperability to be viable
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Registries (Feature Type Catalogue in particular)
Ontologies
Ontologies – not so scary
Authoritative terms with registered relationships
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No attempt to describe everything!
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Build these as stuff gets implemented
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Feature Type Catalogue is an ontology
Robustness and Scalability
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Quality of service
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Formal semantics allows:
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redundancy
brokering “best” services
caching
Means: esoteric information models impact on real
world performance
Future Proofing
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Planning for linkages with existing and emerging
frameworks (e.g. OpenDAP)
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Standards will undergo evolutionary change
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Attention has been paid to how new standards are
adopted
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Extension points via ontology management
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Registry the key to adoption process
Adoption Process
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Rationale (e.g. SEEGrid Roadmap and viewpoints)
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Migration strategy if evolutionary change
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Register complete suite of components required to
exploit
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Extend ontology to document new capabilities
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Maybe create gateways, wrappers, etc to aid
integration
Two critical challenges
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Factor data and service models so that processing
services can act on data instances
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Phase 1
Establish a network accessible Feature Type
Catalogue and governance processes
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Solve how to serve embedded ontology and referenced
vocabularies in a consistent way
Phase 2