information services for dynamically assembled semantic grids

Information Services for Information Services for Dynamically Assembled Dynamically Assembled

Semantic GridsSemantic Grids Mehmet S. Aktas, Geoffrey C. Fox, Marlon PierceMehmet S. Aktas, Geoffrey C. Fox, Marlon PierceCommunity Grids Laboratory, INDIANA UNIVERSITYCommunity Grids Laboratory, INDIANA UNIVERSITY

www.opengrids.org

The First International Conference on Semantics, Knowledge The First International Conference on Semantics, Knowledge and Grid – and Grid – SKG 2005SKG 2005, , Beijing, ChinaBeijing, China

04/19/2304/19/23 SKG-05, BeijingSKG-05, Beijing

Context as Service MetadataContext as Service Metadata ContextContext is metadata associated to both services and is metadata associated to both services and

their activitiestheir activities Context can beContext can be

• independent of any interactionindependent of any interaction slowly varying, quasi-static contextslowly varying, quasi-static context

• generated as result of interactiongenerated as result of interaction dynamic contextdynamic context

• Example: information associated to an activity or sessionExample: information associated to an activity or session GagglesGaggles: Collection of Services that: Collection of Services that

• are set of actively collaborating managed services for a are set of actively collaborating managed services for a particular common goalparticular common goal

• generate events as result of interactionsgenerate events as result of interactions• are very small part of the whole Gridare very small part of the whole Grid


Motivating Scenario: Pattern Informatics (PI) in a Grid Environment

PI in a Grid environment:• Hotspot forecasts are made using publicly available

seismic records. Southern California Earthquake Data Center Advanced National Seismic System (ANSS) catalogs

• Code location is unimportant, can be a service through remote execution

• Results need to be visualized, stored, shared, modified

• Grid/Web Services can provide these capabilities


Support for slowly varying, quasi-static metadata• How do we support both prescriptive and descriptive metadata? How do we support both prescriptive and descriptive metadata?

• How do we enforce up-to-date information in registries?How do we enforce up-to-date information in registries? Support for dynamic session related metadata

• How do we manage dynamic workflows?How do we manage dynamic workflows?

• How do we enable correlation of service activities?How do we enable correlation of service activities?

Information Information Requirements in Requirements in PI GIS GridPI GIS Grid

http://..../..../..txt

2WMS

WFS

HP Search

Data Filter

PI Code

Data Filterhttp://..../..../tmp.xml

3

5,6,74WMS Client

1

PI GIS GRID


Context Information Services Context Information Services MotivationsMotivations

Need to provide information describing services independent Need to provide information describing services independent of their interactions.of their interactions.• generic generic andand domain specificdomain specific characteristics of servicescharacteristics of services

Need to manage all information associated with services for;Need to manage all information associated with services for;• correlating activitiescorrelating activities of widely distributed services of widely distributed services• enabling enabling uniform query capabilitiesuniform query capabilities to both conversation- to both conversation-

based or monolog context informationbased or monolog context information ““Give me list of services satisfying C:{a,b,c..} QoS requirements Give me list of services satisfying C:{a,b,c..} QoS requirements

and participating S:{x,y,z..} sessions”and participating S:{x,y,z..} sessions”• management of eventsmanagement of events especially in multimedia especially in multimedia

collaborationcollaboration• providing information to enableproviding information to enable

session failure recoverysession failure recovery capabilities capabilities


Problem StatementProblem Statement

What is a novel process of building Information Services for both dynamic, session related and slowly varying, static context of widely distributed services in Gaggles?


What is WS-Context?What is WS-Context? Repository of Context InformationRepository of Context Information Allows forAllows for

• Sharing Context info: metadata related to a particular Sharing Context info: metadata related to a particular transaction in multiple Web Service interactionstransaction in multiple Web Service interactions

• Sharing data: data in multiple Web service interactionsSharing data: data in multiple Web service interactions

Nicely put, its a Nicely put, its a Distributed VariationDistributed Variation of Shared Memory of Shared Memory Context Information dependent on the type of activityContext Information dependent on the type of activity

Identify a transaction coordinatorIdentify a transaction coordinator Recovery information in event of a failureRecovery information in event of a failure Sharing info between participants (Security tokens, Sharing info between participants (Security tokens,

certificates, transaction IDs…)certificates, transaction IDs…)


Architectural Design RequirementsArchitectural Design Requirements UniformityUniformity

• need consistent interface to both static and dynamic contextneed consistent interface to both static and dynamic context InteroperabilityInteroperability

• need to leverage existing WS standards (UDDI, WS-need to leverage existing WS standards (UDDI, WS-Context) for service discovery and communicationContext) for service discovery and communication

PersistencePersistence• need to provide high availability of informationneed to provide high availability of information

DynamismDynamism• need to handle metadata based on changing user demandsneed to handle metadata based on changing user demands

PerformancePerformance• need to support dynamic changes with min. delayneed to support dynamic changes with min. delay


WSDL

Extended UDDI Registry

Service

HTTP

Client

WSDL

HTTP(S)

Storage

AccessDatabase

WSDL

JDBC

Expeditor

WSDL

NBNode Querying

Publishing

andSequencer

The Architecture of Context Information ServiceThe Architecture of Context Information Service

Client

WSDL

Client

WSDL


FFault ault TTolerant olerant HHigh igh PPerformance erformance IInformation nformation SServices (ervices (FTHPISFTHPIS))

Performance, compatibility, uniform interfacePerformance, compatibility, uniform interface• cachingcaching

Expeditor Module using Tuple Spaces paradigmExpeditor Module using Tuple Spaces paradigm• web service based programming interface, UDDI & WS-web service based programming interface, UDDI & WS-

ContextContext Querying and Publishing ModulesQuerying and Publishing Modules

From single point of failure to distributed system: From single point of failure to distributed system: fault tolerancefault tolerance• dynamic replicationdynamic replication

Access ModuleAccess Module Storage ModuleStorage Module

• multi-publisher multicasting messagingmulti-publisher multicasting messaging NaradaBrokering (NaradaBrokering (www.naradabrokering.orgwww.naradabrokering.org))


Distributed Dynamic Context ManagementDistributed Dynamic Context Management

Computer Boundaries

WSDL

Extended UDDI Registry

Service

HTTP(S)

Client

WSDL

HTTP(S)

Gaggle Boundaries

Storage

AccessDatabase

WSDL

JDBC

Expeditor

WSDL

NBNode Querying

Publishing

and Sequencer

NB plays role is for fast andreliable multi-publisher, multicast messaging among peer IS Services


<?xml version="1.0" encoding="UTF-8"?><?xml version="1.0" encoding="UTF-8"?> <soap:Envelope xmlns:soap="http://www.w3..."><soap:Envelope xmlns:soap="http://www.w3..."> <soap:Header encodingStyle=“URL"<soap:Header encodingStyle=“URL" mustUnderstand="true">mustUnderstand="true"> <<contextcontext xmlns=“ctxt schema“ timeout="100"> xmlns=“ctxt schema“ timeout="100"> <<context-idcontext-id>http..</context-id>>http..</context-id> <<context-servicecontext-service> http.. </context-service>> http.. </context-service> <<context-managercontext-manager> http.. </context-service>> http.. </context-service> <<activity-listactivity-list mustUnderstand="true" mustPropagate="true">mustUnderstand="true" mustPropagate="true"> <<p-servicep-service>http://../WMS</p-service>>http://../WMS</p-service> <<p-servicep-service>http://../HPSearch</p-service>>http://../HPSearch</p-service> </activity-list></activity-list> </context></context> </soap:Header></soap:Header>

SOAP header

for Context

The Pattern Informatics GIS-SOA based workflow application

5,6: WMS starts a session, invokes HPSearch to run workflow script for PI Code with a session id

7,8,9: HPSearch runs the workflow script and generates output file in GML format (& PDF Format) as result

10: HPSearch writes the URI of the of the output file into Context

11: WMS polls the information from Context Service

12: WMS retrieves the generated output file by workflow script and generates a map

<context xsd:type="ContextType"timeout=“100"><context xsd:type="ContextType"timeout=“100"><context-service><context-service>http://.../HPSearch</ http://.../HPSearch</ context-context-

service>service>

<content> HPSearch associated additional data <content> HPSearch associated additional data generated during execution of workflow. </content>generated during execution of workflow. </content>

</context></context>

service associated

<context xsd:type="ContextType"timeout=“100"><context xsd:type="ContextType"timeout=“100"><context-service><context-service>http://.../WMS</ http://.../WMS</ context-service>context-service>

<activity-list mustUnderstand="true" <activity-list mustUnderstand="true" mustPropagate="true"> mustPropagate="true">

<service>http://.../WMS</service> <service>http://.../WMS</service>

<service>http://.../HPSearch</service> <service>http://.../HPSearch</service>

</activity-list> </activity-list>


session

<context xsd:type="ContextType"timeout=“100"><context xsd:type="ContextType"timeout=“100"><context-service><context-service>http://.../HPSearch</ http://.../HPSearch</ context-context-

service>service><parent-context>http://../abcdef:012345<parent-<parent-context>http://../abcdef:012345<parent-

context/>context/><content> <content> profile information related WMS profile information related WMS

</content></content>


user profile

<context xsd:type="ContextType"timeout=“100"><context xsd:type="ContextType"timeout=“100"> <context-id>http://../abcdef:012345<context-id/><context-id>http://../abcdef:012345<context-id/><context-service><context-service>http://.../HPSearch</ http://.../HPSearch</ context-context-

service>service>

<content>http://danube.ucs.indiana.edu:8080\x.xml</c<content>http://danube.ucs.indiana.edu:8080\x.xml</content>ontent>


shared state

<context xsd:type="ContextType"timeout=“100"><context xsd:type="ContextType"timeout=“100"><context-service><context-service>http://.../HPSearch</ http://.../HPSearch</ context-service>context-service><parent-context>http://../abcdef:012345<parent-context/><parent-context>http://../abcdef:012345<parent-context/><content> <content> shared data for HPSearch activity </content>shared data for HPSearch activity </content>

<activity-list mustUnderstand="true" mustPropagate="true"> <activity-list mustUnderstand="true" mustPropagate="true">

<service>http://.../DataFilter1</service> <service>http://.../DataFilter1</service>

<service>http://.../PICode</service> <service>http://.../PICode</service>

<service>http://.../DataFilter2</service> <service>http://.../DataFilter2</service>

</activity-list> </activity-list>


activity

3WMS

WFS

http://..../..../..txt

HP Search

Data Filter

PI Code

Data Filterhttp://..../..../x.gml

Context Information Service

4

7,8,9

10

6

5,11

WMS Client

Extended UDDI

0

1

2


System Status - ISystem Status - I Extended UDDI Metadata ServiceExtended UDDI Metadata Service

• OGC (Open Geographic Information Systems (GIS) Consortium) OGC (Open Geographic Information Systems (GIS) Consortium) specific service registry, up-to-date registry entries, metadata oriented specific service registry, up-to-date registry entries, metadata oriented query capabilities and XPATH query capabilities..query capabilities and XPATH query capabilities..

• Status: 100 % completed. Status: 100 % completed. www.opengrids.org/extendeduddiwww.opengrids.org/extendeduddi• Application domains: PI GIS Grid (UC at Davis), IEISS GIS Grid Application domains: PI GIS Grid (UC at Davis), IEISS GIS Grid

(LANL)(LANL) WS-Context Complaint Metadata ServicesWS-Context Complaint Metadata Services

• WS-Context compatibility, support for shared dynamic contextWS-Context compatibility, support for shared dynamic context• Status: 100 % completed. Status: 100 % completed. www.opengrids.org/wscontextwww.opengrids.org/wscontext• Application domains: PI GIS Grid (UC at Davis), IEISS GIS GridApplication domains: PI GIS Grid (UC at Davis), IEISS GIS Grid


System Status - IISystem Status - II

Unified UDDI & WS-Context Metadata ServicesUnified UDDI & WS-Context Metadata Services• Both WS-Context and UDDI compatibility, uniform Both WS-Context and UDDI compatibility, uniform

programming interface to dynamic & static metadata, programming interface to dynamic & static metadata, caching (high performance), support for session-failure caching (high performance), support for session-failure recovery capabilitiesrecovery capabilities

• www.opengrids.org/wscontextwww.opengrids.org/wscontext

• Application domains: PI GIS Grid (UC at Davis), IEISS Application domains: PI GIS Grid (UC at Davis), IEISS GIS Grid, Global MMCS projectGIS Grid, Global MMCS project


Conclusions & Future WorkConclusions & Future Work There may be following There may be following gapsgaps in Semantic/Traditional Grid in Semantic/Traditional Grid

Information Services.Information Services.• needneed forfor management of widely management of widely distributed, shared distributed, shared

session-related dynamic metadatasession-related dynamic metadata• need forneed for enabling enabling session failure recoverysession failure recovery • needneed for for uniform search interfaceuniform search interface to both interaction to both interaction

independent and conversation-based contextindependent and conversation-based context We introduce a novel We introduce a novel architecturearchitecture addressing these gaps by addressing these gaps by

taking into account; taking into account; • efficient metadata access and storageefficient metadata access and storage, , decentralized fault tolerant decentralized fault tolerant

storage capabilitystorage capability, , uniform interface to contextuniform interface to context, , minimum response minimum response latencylatency

We plan on investigating We plan on investigating research issuesresearch issues related with related with fault fault tolerance and consistency as future worktolerance and consistency as future work. We also want to . We also want to evaluate the system as whole through extensive performance evaluate the system as whole through extensive performance tests.tests.


Location of information and software for Location of information and software for dependent Grid Projectsdependent Grid Projects

htpp://www.naradabrokering.orghtpp://www.naradabrokering.org provides Web service provides Web service (and JMS) compliant (and JMS) compliant distributed publish-subscribe distributed publish-subscribe messagingmessaging (software overlay network) (software overlay network)

http://www.crisisgrid.orghttp://www.crisisgrid.org is an OGC (open geospatial is an OGC (open geospatial consortium) Geographical Information System (GIS) consortium) Geographical Information System (GIS) compliant compliant GIS and Sensor Grid.GIS and Sensor Grid.

http://www.opengrids.orghttp://www.opengrids.org has WS-Context, Extended has WS-Context, Extended UDDI etc.UDDI etc.

information services for dynamically assembled semantic grids

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