1. 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.edugcf@indiana.edu http://www.infomall.orghttp://www.infomall.org

2. 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. 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 and ability 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. 4 XML Databases of Importance We choose a message based interface to 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 for controlling 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. 5 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 WFS: Geographical Information System compatible XML Metadata Services

6. 6 WMS uses WFS that uses data sources Northridge2 Wald D. J. -118.72,34.243 - 118.591,34.176

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

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

9. 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. 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. 11 Information Service WSDL IS Client WSDL HTTP(S) WSDL IS Client DB JDBC Extended WS-Context Service dynamic metadata IS Client WSDL DB JDBC Extended UDDI Registry Service UDDI Version 3.0 WSDL Service Interface Descriptions uddi_api_v3_portType.wsdl WSDL WS-Context Ver1.0 ws-context.wsdl WSDL interaction-independent relatively static metadata WSDL Optimized for Scalability Optimized for Performance

12. 12 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 Applications I – Workflow based Geographical Information System (GIS) Grids

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

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

15. 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. 16 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. Application – Context Store usage in communication of mobile Web Services

17. 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. 18 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. Application – Context Store usage in multimedia collaboration environment such as GlobalMMCS

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