Web Service Information Systems and Applications

1. Web Service Information Systems and Applications GGF16 Semantic Grid Workshop Athens Greece February 15 2006 Geoffrey Fox Computer Science, Informatics, Physics Pervasive Technology Laboratories Indiana University Bloomington IN 47401 http://grids.ucs.indiana.edu/ptliupages/presentations/ gcf@indiana.eduhttp://www.infomall.org

2. Different Metadata Systems • There are many WS-* specifications addressing meta-data defined broadly • WS-MetadataExchange • WS-RF • UDDI • WS-ManagementCatalog • And many different implementations from (extended) UDDI through MCAT of the Storage Research Broker • And of course representations including RDF and OWL • Further there is system metadata (such as UDDI for core services) and metadata catalogs for each application domain such as WFS (Web Feature Service) for GIS (Geographical Information Systems) • They have different scope and different QoS trade-offs • e.g. Distributed Hash Tables (Chord) to achieve scalability in large scale networks • WS-Context • ASAP • WBEM • WS-GAF

3. Different Trade-offs • It has never been clear to me how a poor lonely service is meant to know where to look up meta-data and if it is meant to be thought up as a database (UDDI, WS-Context) or as the contents of a message (WS-RF, WS-MetadataExchange) • We identified two very distinct QoS tradeoffs • 1) Large scale relatively static metadata as in (UDDI) catalog of all the world’s services • 2) Small scale highly dynamic metadata as in dynamic workflows for sensor integration and collaboration • Fault-tolerance andability to support dynamic changes with few millisecond delay • But only a modest number of involved services (up to 1000’s in a session) • Need Session NOT Service/Resource meta-data so don’t use WS-RF

4. XML Databases of Importance • We choose a message based interfaceto a backend database • We have two pieces of technology with different trade-offs but each could store any meta-data but with different QoS • WS-Context designed forcontrolling a workflow • (Extended) UDDI exemplified by semantic service discovery; can now be Grimoires • WFS provides general application specific XML data/meta-data repository built on top of a hybrid system supported by UDDI and WS-Context • These have different performance, scalability and data unit size requirement • In our implementation, each is currently “just an Oracle/MySQL” database front ended by filters that convert between XML (GML for WFS) and object-relational Schema • Example of Semantics (XML) versus representation (SQL) difference • OGSA-DAI offers Grid interface to databases – we could use but don’t as we only need to expose WFS and not MySQL to Grid

5. WFS: Geographical Information System compatible XML Metadata Services • Extended UDDI XML Metadata Service (alternative to OGC Web Registry Services) supports WFS GIS Metadata Catalog (functional metadata), user-defined metadata ((name, value) pairs), up-to-date service information (leasing), dynamically updated registry entries. • Our approach enables advanced query capabilities • geo-spatial and temporal queries , • metadata oriented queries, • domain independent queries such as XPATH, XQuery on metadata catalog. • http://www.opengrids.org/extendeduddi/index.html

6. WMS uses WFS that uses data sources <gml:featureMember> <fault> <name> Northridge2 </name> <segment> Northridge2 </segment> <author> Wald D. J.</author> <gml:lineStringProperty> <gml:LineStringsrsName="null"> <gml:coordinates> -118.72,34.243 -118.591,34.176 </gml:coordinates> </gml:LineString> </gml:lineStringProperty> </fault> </gml:featureMember>

7. Electric Power and Natural Gas data from LANL Interdependent Critical Infrastructure Simulations WMS Interface Zoom-in Zoom-out FeatureInfo mode Measure distance mode Clear Distance Drag and Drop mode Refresh to initial map

8. Integrating Archived Web Feature Services and Google Maps Google maps can be integrated with Web Feature Service Archives to filter and browse seismic records.

9. Context as Service Metadata • We define all metadata (static, semi-static, dynamic) relevant to a service as “Context”. • Context can be associated to a single service, a session (service activity) or both. • Context can be independent of any interaction • slowly varying, quasi-static context • Ex: type or endpoint of a service, less likely to change • Context can be generated as result of service interactions • dynamic, highly updated context • information associated to an activity or session • Ex: session-id, URI of the coordinator of a workflow session

10. Hybrid XML Metadata Services –> WS-Context + extendedUDDI • We combine functionalities of these two services: WS-Context AND extendedUDDI in one hybrid service to manage Context (service metadata). • WS-Context controlling a workflow • (Extended) UDDI supporting semantic service discovery • This approach enables uniform query capabilities on service metadata catalog. • http://www.opengrids.org/wscontext/index.html

11. IS Client IS Client IS Client WSDL WSDL WSDL HTTP(S) WSDL WSDL WSDL Information Service Optimized forPerformance Optimized forScalability WS-Context Ver1.0 ws-context.wsdl WSDL WSDL UDDI Version 3.0 WSDL Service Interface Descriptions uddi_api_v3_portType.wsdl WSDL WSDL Extended WS-Context Service Extended UDDI Registry Service JDBC JDBC DB DB interaction-independent relatively static metadata dynamic metadata

12. Applications I – Workflow based Geographical Information System (GIS) Grids • CGL GIS Research focuses on open source software for Grids to support scientific/visualization applications. • some focus areas are earthquake prediction and simulating energy interdependencies with GIS Grids. • http://www.crisisgrid.org • We use WS-Context complaint Information Services for storing transitory metadata for distributed state information. • We use extended UDDI Information Services for providing search/store/access to geo-spatial domain-specific metadata catalogs • All data filters output data as though they were a WFS so data filters and sensors interchangeable

13. Typical use of Grid Messaging in NASA Sensor Grid WFS is Universal Interface GIS Grid Grid Eventing Datamining Grid

14. Workflow Extended UDDI and WS-Context compliant Information Services handle with both quasi-static, slowly varying and dynamic highly updated metadata.

15. Real Time GPS and Google Maps Subscribe to live GPS station. Position data from SOPAC is combined with Google map clients. Select and zoom to GPS station location, click icons for more information.

16. Application – Context Store usage in communication of mobile Web Services • Handheld Flexible Representation (HHFR) is an open source software for fast communication in mobile Web Services. HHFR supports: • streaming messages, separation of message contents and usage of context store. • http://www.opengrids.org/hhfr/index.html • We use WS-Context service as context-store for redundant message parts of the SOAP messages. • redundant data is static XML fragments encoded in every SOAP message • Redundant metadata is stored as context associated to service conversion in place • The empirical results show that we gain 83% in message size and on avg. 41% on transit time by using WS-Context service.

17. Optimizing Grid/Web Service Messaging Performance The performance and efficiency of Web Services can be greatly increased in conversational and streaming message exchanges by removing the redundant parts of the SOAP message.

18. Application – Context Store usage in multimedia collaboration environment such as GlobalMMCS • GlobalMMCS is audio/video conferencing system. http://www.globalmmcs.org • WS-Context service is used as session metadata catalog for describing audio/video streams in a session. • stream metadata might have various descriptive information such as starting and ending RTP packet numbers, what topic is the stream is published, etc.. • metadata is stored associated with sessions • WS-Context service provides search/store/access interface for stream metadata as archival store. • Queries support archived (find all relevant data in past) metadata • Queries support session – metadata relations (find all metadata for a given session) • Session discovery (find a session with given properties) • Clients query context store for information to be able to replay/playback an audio/video stream during or after conference session.

19. Archived stream Annotation / WB e - Annotation e - Annotation e-Annotation Archived Stream Annotated e-Annotation Player Player Stream Player Whiteboard player player Whiteboard Player Archived Real Time Real TimeStream List Stream List Player Real time Real time stream Archieved stream list player stream list