Services and the Semantic Grid

1. Services and the Semantic Grid SKG2005 Beijing China November 28 2005 Geoffrey Fox Computer Science, Informatics, Physics Pervasive Technology Laboratories Indiana University Bloomington IN 47401 gcf@indiana.edu http://www.infomall.org

2. Data Deluged Science • In the past, we worried about data in the form of parallel I/O or MPI-IO, but we didn’t consider it as an enabler of new science and new ways of computing • Data assimilation was not central to HPCC • DoE ASCI set up because didn’t want test data! • Now particle physics will get 100 petabytes from CERN • Nuclear physics (Jefferson Lab) in same situation • Use around 30,000 CPU’s simultaneously 24X7 • Weather, climate, solid earth (EarthScope) • Bioinformatics curated databases (Biocomplexity only 1000’s of data points at present) • Virtual Observatory and SkyServer in Astronomy • Environmental Sensor nets

3. Information/Knowledge Grids • Distributed (10’s to 1000’s) of data sources (instruments, file systems, curated databases …) • Data Deluge: 1 (now) to 100’s petabytes/year (2012) • Moore’s law for Sensors • Possible filters assigned dynamically (on-demand) • Run image processing algorithm on telescope image • Run Gene sequencing algorithm on compiled data • Needs decision support front end with “what-if” simulations • Metadata (provenance) critical to annotate data • Integrate across experiments as in multi-wavelength astronomy Data Deluge comes from pixels/year available

4. SS Database SS SS SS SS SS SS SS Semantically Rich Services with a Semantically Rich Distributed Operating Environment Filter Service OS FS FS MD MD FS OS OS FS OS Portal OS FS FS FS FS FS MD MD OS MD OS OS FS Other Service FS FS FS FS MD OS OS OS FS FS FS MD MD FS OS FS MetaData FS FS FS MD Sensor Service SS SS SS SS SS SS SS SS SS SS

5. Semantic Grid and Services • Implications of SOA (Service Oriented Architectures) for SG (Semantic Grid) • Build services to implement SG • Implications of SG for SOA • Build metadata rich systems of services using SG • Services receive data in SOAP messages, manipulate it and produce transformed data as further messages • Meta-data is carried in SOAP messages • Meta-data controls processing and transport of SOAP Messages • Knowledge is created from data by services • The Grid enhances Web services with semantically rich system and application specific management • One must exploit and work around the different approaches to meta-data and their manipulation in Web Services

6. H1 H2 H3 H4 Body Service F1 F2 F3 F4 Container Workflow Container Handlers Structure of SOAP Messages • SOAP Messages have System information in the header including WS-Policy based meta-data defining processing options • Processed by Handlers • Application data and meta-data is the body (controversies here!) • Processed by the Service itself • Some meta-data like WS-RF is logically “only in messages” • Other like that in WS-Context or the SRB are stored in logical equivalent of XML databases • We only need to preserve semantic structure (XML/SOAP Infoset) so transport in fast XML and store in efficient relational databases

7. What Type of Services are there? • There are a horde of support services supplying security, collaboration, database access, user interfaces • The support services are either associated with system or application • We will study the WS-* and GS-* which implicitly or explicitly define many support services • There are generalized filter services which are applications that accept messages and produce new messages with some data derived from that in input • Simulations (including PDE’s and reactive systems) • Data-mining • Transformations • Agents • Reasoning are all termed filters here • There are services like “author ontology”, “parse RDF” or “attach provenance” that directly support Semantic Grid • But all services and their interactions are bathed in sea of meta-data and so implicitly need and support the Semantic Grid

8. It’s a Composite Hierarchical World • Filters can be a workflow which means they are “just collections of other simpler services” • One needs meta-data to control the workflow • Services are programs that accept messages and produce messages • Grids are a distributed collection of services supporting managed shared resources • Management requires meta-data • Grids are distributed systems that accept distributed messages and produce distributed result messages • Can always talk about Grids and view a service or a workflow as a special case of a Grid • It just requires meta-data to send a message to a Grid and it routed to “correct computer” holding “requested service” • Meta-data allows mapping of virtual to real addresses

9. SOAP Message Streams Wisdom SS AnotherService Database Decisions SS Data Raw Data Knowledge SS Information SS Knowledge Data Information SS Raw Data SS Information AnotherService SS Data Data SS Raw Data Raw Data is same as outward facing applicationservice SOAP Message Streams AnotherGrid AnotherGrid Grids of Grids Architecture Semantically Rich Services with a Semantically Rich Distributed Operating Environment Filter Service OS FS FS MD MD FS OS OS FS OS Portal OS FS FS FS FS FS MD MD OS MD OS OS FS Other Service FS FS FS FS MD OS OS OS FS FS FS MD MD FS OS FS MetaData FS FS FS MD Sensor Service SS SS SS SS SS SS SS SS SS SS

10. 4: Application or Community of InterestSpecific Services such as “Run BLAST” or “Look at Houses for sale” 3: Generally Useful Services and Features Such as “Access a Database” or “Submit a Job” or “Semantic Grid” or “Support a Portal” or “Collaborative Visualization” OGSAand otherGGF/W3C/ ……… 2: System Services and Features Handlers like WS-RM, Security, Programming Models like BPELor Registries like UDDI WS-* fromOASIS/W3C/Industry 1: Container and Run Time (Hosting) Environment Apache Axis.NET etc. The Grid and Web Service Institutional Hierarchy

11. The WS-* Infrastructure • Core Grid Services build on and/or extend the 60 or so WS-* Infrastructure specifications which define • 1. Container Model, XML, WSDL … • 2. Service Internet ( (Reliable) Messaging, Addressing) including extensions for high performance transport and representation. This is natural basis for streaming applications • 3. Notification • 4. Workflow and Transactions • 5. Security • 6. Service Discovery • 7. Metadata and State including lifetime • 8. Management (service interactions) • 9. Policy, Agreements • 10. Portals and User Interfaces These categories are directly connected to metadata

12. A List of Web Services 6 • 6) Service Discovery • UDDI(Broadly Supported OASIS Standard) V3 August 2003 • WS-Discovery Web services Dynamic Discovery (Microsoft, BEA, Intel …) February 2004 • WS-ILWeb Services Inspection Language, (IBM, Microsoft) November 2001 • Note WS-Context as a metadata catalog and WS-Management Catalog are examples of related services • There are many UDDI extensions such as Grimoires from UK OMII which often are essentially providing semantic enrichment Discovery is just accessing part of meta-data defining a Grid

13. A List of Web Services 7 • 7) Metadata and State • RDFResource Description Framework (W3C) Set of recommendations expanded from original February 1999 standard • DAML+OIL combining DAML (Darpa Agent Markup Language) and OIL (Ontology Inference Layer) (W3C) Note December 2001 • OWLWeb Ontology Language (W3C) Recommendation February 2004 • WS-MetadataExchange Web Services Metadata Exchange (BEA, IBM, Microsoft, SAP, Sun …) September 2004 • ASAP Asynchronous Service Access Protocol (OASIS) with V1.0 working draft 2B December 11 2004 • WS-GAF Web Service Grid Application Framework (Arjuna, Newcastle University) August 2003 • WBEM Web-Based Enterprise Management including CIM (Common Information Model) from DMTF (Distributed Management Task Force) 2004-2005

14. A List of Web Services 7 • 7) Metadata and State: Resource Framework • WS-RF Web Services Resource Framework (OASIS) including • WS-Resource Framework Web Services Resource 1.2 (OASIS) Public Review Draft 01, 10 June 2005 • WS-ResourceProperties Web Services Resource Properties V1.2 Public Review Draft 01, 10 June 2005 • WS-ResourceLifetime Web Services Resource Lifetime V1.2 Public Review Draft 01, 13 June 2005 • WS-ServiceGroup Web Services Service Group V1.2 Public Review Draft 01, 10 June 2005 • WS-BaseFaults Web Services Base Faults V1.2 Public Review Draft 01, June 13, 2005 These WS-* define syntax of Meta-data (RDF OWL CIM) and how to use it in system (WS-MetadataExchange) – especially headers (WS-RF)

15. Metadata and Service Context • Consider a collection of services working together • Workflow tells you how to specify service interaction but more basically there is shared information or context specifying/controlling collection • WS-RF and WS-GAF have different approaches to contextualization – supplying a common “context” which at its simplest is a token to represent state • More generally core shared information includes dynamic service metadata and the equivalent of configuration information. • Two services linked by a stream are perhaps simplest example of a collection of services needing context • Note that there is a tension between storing metadata in messagesand services. • This is shared versus distributed memory debate in parallel computing

16. Stateful Interactions • There are (at least) four approaches to specifying state • OGSIuse factories to generate separate services for each session in standard distributed object fashion • Globus GT-4and WSRF use metadata of a resource to identify state associated with particular session • WS-GAFuses WS-Context to provide abstract context defining state. Has strength and weakness that reveals less about nature of session • WS-I+ “Pure Web Service” leaves state specification the application – e.g. put a context in the SOAP body • I think we should smile and write a great metadata (semantic) service hiding all these different models for state and metadata

17. Role of WS-Context • There are many WS-* specifications addressing meta-data and both many approaches and many trade-offs • We hear about Distributed Hash Tables (Chord) to achieve scalability in large scale networks • Managed dynamic workflows as in sensor integration and collaboration require • 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 • We are building a WS-Context compliant metadata catalog supporting distributed or central paradigms – see later talk by Mehmet Aktas • Use for OGC Web catalog service with UDDI for slowly varying meta-data

18. A List of Web Services 8 • 8) Management • WS-DistributedManagement Web Services Distributed Management Framework with MUWS and MOWS below (OASIS) • WSDM-MUWS Web Services Distributed Management: Management Using Web Services (OASIS) OASIS Standard March 9 2005 • WSDM-MOWS Web Services Distributed Management: Management of Web Services (OASIS) OASIS Standard March 9 2005

19. A List of Web Services 8- Contd • 8) Management: Microsoft Stack • WS-Management Web Services for Management (Microsoft, Intel, Sun …) August 2005 • WS-Management Catalog The WS-Management Catalog (Microsoft, Intel, Sun …) August 2005 • WS-Transfer Web Service Transfer (Microsoft, BEA, Sonic Software etc.) September 2004 • WS-Enumeration Web Service Enumeration (Microsoft, BEA, Sonic Software etc.) September 2004 These WS-* define exchange of data and meta-data between services

20. A List of Web Services 9 • 9) General Service Characteristics • WS-PolicyFramework Web Services Policy Framework (BEA, IBM, Microsoft, SAP …) September 2004 • WS-PolicyAttachment Web Services Policy Attachment (BEA, IBM, Microsoft, SAP …) September 2004 • WS-PolicyAssertions Web Services Policy Assertions Language (BEA, IBM, Microsoft, SAP) 18 December 2002 (Superseded by WS-PolicyFramework) • WS-Agreement Web Services Agreement Specification (GGF under development) 9 August 2004 These WS-* define syntax of Meta-data defining structure of distributed System Grids are managed (meta-data enhanced) distributed collections of Internet Scale services

21. Activities in Global Grid Forum Working Groups Use the sea of meta-data supported by Semantic Grid

22. Two-level Programming I Service Data • The Web Service (Grid) paradigm implicitly assumes a two-level Programming Model • We make a Service (same as a “distributed object” or “computer program” running on a remote computer) using conventional technologies • C++ Java or Fortran Monte Carlo module • Data streaming from a sensor or Satellite • Specialized (JDBC) database access • Such services accept and produce data from users files and databases • The Grid is built by coordinating such services assuming we have solved problem of programming the service

23. Service1 Service3 Service2 Service4 Two-level Programming II • The Grid is discussing the composition of distributed services with the runtime interfaces to Grid in analogy to UNIX pipes/data streams • Familiar from use of UNIX Shell, PERL or Python scripts to produce real applications from core programs • Such interpretative environments are the single processor analog of Grid Programming • Some projects like GrADS from Rice University are looking at integration between service and composition levels but dominant effort looks at each level separately

24. Web Service 1 WS 2 WS N-1 Web Service N 3 Layer Programming Model Level 1 Programming inside services Application expressed in in Java Fortran C++ MPI etc. WS-* Infrastructure Level 2 Programming choosing services by virtualization Application Semantics (Metadata, Ontology) Semantic Grid Level 3 Grid Programming composing multiple services Service Workflow, Transactions, Mediation Substantial work in UK e-Science program, international semantic web community

25. Information Architecture and Semantic Grid • WS-* provides key low level capability but deliberately does not define an information (data) architecture and leaves this to domain specific specification activities such as CellML/SBML for biology, WFS/GML for GIS and XGSP for Collaboration • WS-* does define a primitive service discovery (UDDI) and meta-data capabilities including WS-Context, WS-RF, RDF and WS-MetadataExchange already discussed. • GGF defines Grid data capabilities including info-D (publish/subscribe) and OGSA-DAI for data repositories • Semantic Grid uses WS-* and GS-* extending meta-data and service discovery with data-mining and reasoning

26. 3 XML Databases of Importance • WS-Context controlling a workflow • (Extended) UDDI supporting semantic service discovery • WFS or ASFS (see later) provides application specific data/meta-data repository) • 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

27. Information Management/Processing • SOAP messages transport information expressed in a semantically rich fashion between sources and services that enhance and transform information so that complete system provides • Semantic Web technologies like RDF and OWL help us have rich expressivity • Data  Information  Knowledgetransformation • We build application specific information management/transformation systems ASIS for each application domain • One special domain is the system itself where the metadata associated with services, sessions, Grids, messages, streams and workflow is itself managed and supported by an SIIS

28. Generalizing a GIS • Geographical Information Systems GIS have been hugely successful in all fields that study the earth and related worlds • They define Geography Syntax (GML) and ways to store, access, query, manipulate and display geographical features • In SOA, GIS corresponds to a domain specific XML language and a suite of services for different functions above • However such a universal information model has not been developed in other areas even though there are many fields in which it appears possible • BIS Biological Information System • MIS Military Information System • IRIS Information Retrieval Information System • PAIS Physics Analysis Information System • SIIS Service Infrastructure Information System

29. ASIS Application Specific Information System I • a) Discovery capabilities that are best done using WS-* standards • b) Domain specific metadata and data including search/store/access  interface. (cf WFS). Lets call generalization ASFS (Application Specific Feature Service) • Language to express domain specific features (cf GML). Lets call this ASL (Application Specific language) • Tools to manipulate information expressed in language and key data of application (cf coordinate transformations). Lets call this ASTT (Application specific Tools and Transformations) • ASL must support Data sources such as sensors (cf OGC metadata and data sensor standards) and repositories. Sensors need (common across applications) support of streams of data • Queries need to support archived (find all relevant data in past)   and streaming (find all data in future with given properties) • Note all AS Services behave like Sensors and all sensors are wrapped as services • Any domain will have “raw data” (binary) and that which has been filtered to ASL. Lets call ASBD (Application Specific Binary Data)

30. Filter, Transformation, Reasoning, Data-mining, Analysis ASRepository AS Tool (generic) AS Service (user defined) AS Tool (generic) ASVS Display AS“Sensor” Messages using ASL ASIS Application Specific Information System II • Lets call this ASVS (Application Specific Visualization Services) generalizing WMS for GIS • The ASVS should both visualize information and provide a way of navigating (cf GetFeatureInfo) database (the ASFS) • The ASVS can itself be federated and presents an ASFS output interface • d) There should be application service interface for ASIS from which all ASIS service inherit • e) There will be other user services interfacing to ASIS • All user and system services will input and output data in ASL using filters to cope with ASBD

31. Directly GS-* WS-* Filters/ASTT MilitaryInformationManagement System Everything Is a Service or a message/ Information Nugget ASVS

32. MIOor Military Information Object Unit of Managed Information expressed in ASL ASFS OGSA-DAI and Sensor Standards Info-DWS-Notification WS-Eventing

33. IS = Receive Request/Select Issue Request/Select Receive Request/Select Request Status Get Status Get Status ASL Data Get ASL Data Get ASL Data Put BFS = Filter Resource Information Resource InformationService(Sensor,Service orRepository) Basic FilterService Filters either transform or aggregate Information

34. A Filter Service is a general workflow (the microscopic workflow) of Basic Filter Services BFS FS = BFS BFS BFS BFS The output of a Filter Service is indistinguishable from that of an IS BFS A transport link supports asynchronous publish/subscribe semantics and Web Service Reliable messaging fault tolerance Transport links can be multicast to support collaboration (typically for last link before or after Presentation Service) or replication for fault tolerance.

35. Top IS could be produced by a Filter Service IS IS IS IS Gridlet = FS FS FS FS The basic unit (Gridlet) transforms and aggregates application specific information Gridlets are composed using Grid of Grids concept

36. IS Gridlet IS Gridlet IS Gridlet IS Gridlet IS Gridlet IS Gridlet IS Gridlet IS Gridlet Federation Macrosopic Workflow General System Services ----------------------- Messaging/Data transport Notification Security Fault Tolerance Metadata Directory Collaboration Replica Management Search Planning Construction Management Session Management Presentation ASVS Portal Data  Information  Knowledge as messages flow from original sources to top of Filter Grid

37. SOAP Message Streams Wisdom SS AnotherService Database Decisions SS Data Raw Data Knowledge SS Information SS Knowledge Data Information SS Raw Data SS Information AnotherService SS Data Data SS Raw Data Raw Data is same as outward facing applicationservice SOAP Message Streams AnotherGrid AnotherGrid Grids of Grids Architecture Semantically Rich Services with a Semantically Rich Distributed Operating Environment Filter Service OS FS FS MD MD FS OS OS FS OS Portal OS FS FS FS FS FS MD MD OS MD OS OS FS Other Service FS FS FS FS MD OS OS OS FS FS FS MD MD FS OS FS MetaData FS FS FS MD Sensor Service SS SS SS SS SS SS SS SS SS SS

38. Summary • Virtualization everywhere • Focus on semantics not representation to get performance combined with expressivity for transport and data access • All this enabled by powerful meta-data services • Grids add management to rich but potentially chaotic set of Web Services; • management and coherence enabled by meta-data • Can define general information architectures (ASIS, GIS, SIIS) for both applications and system • Knowledge from filters that span simulations, data-mining, reasoning and agents • A service is just a special case of a Grid • Build systems from SubGrids (Gridlets)