1. The Earth System Curator Metadata Representations Prototype Portal in Collaboration with ESMF and ESG Rocky Dunlap Spencer Rugaber Georgia Tech

5. Who we are Cecelia DeLuca, NCAR V. Balaji, GFDL/Princeton University Don Middleton, NCAR Chris Hill, MIT Serguei Nikonov, GFDL Sylvia Murphy, NCAR Luca Cinquini, NCAR Julien Chastang, NCAR Spencer Rugaber, Georgia Tech Leo Mark, Georgia Tech Rocky Dunlap, Georgia Tech Plus other collaborators: NMM, Metafor, BFG2, and others

6. What is the Earth System Curator? The goal of Curator is to link climate datasets with a detailed description of the model that ran to produce the dataset Transparent access to models and datasets Use cases for climate model metadata  Provenance (history of what happened)  Archival and search (for models and datasets)  Model inter-comparison  Compatibility checking  Generation of coupler components

7. Collaborations with Related Projects Earth System Modeling Framework (ESMF)  Software infrastructure to facilitate building numerical Earth System models  Component-based model development  Built in tools for managing common modeling tasks (coupling fields, calendars, grid creation, etc). Earth System Grid (ESG)  A large scale distributed portal for hosting data produced by Earth System models  Services such as dataset ingest, faceted search, dataset browsing, viewing metadata, downloading datasets

8. Representations of Curator Metadata UML RDF/OWL XML/XML Schema Relational DB - SQL

9. UML Unified Modeling Language What it is  A visual modeling language for representing software systems Source  OMG Standard Motivation  Conceptual modeling, human to human communication of the model, object oriented representation  of the 13 diagrams in UML 2.0, we are using one: class diagram  static structure in terms of classes, attributes on classes, relationships between classes

10. UML Metamodel  Access to metamodel for creating UML Profiles  ability to define a subset of UML used for building your own models Tool support  Enterprise Architect – recommended  Others – Rational Rose, Poseidon, ArgoUML, Microsoft Visio Constraint +Query Language – Object Constraint Language (OCL)

11. http://swiki.cc.gatech.edu:8080/Curator/46

12. RDF/OWL What it is  “Semantic web” ontology language  Primary modeling constructs are properties and classes  Conceptual implementation language (not low level like XML)  RDF – Resource Description Framework Based on {subject, predicate, object} triples  OWL – Web Ontology Language (2.0 coming soon!) Strong theoretical basis on Description Logics Source  W3C standard

13. RDF/OWL Motivations  Now a widely accepted standard  Simple data model, but OWL still allows complex class descriptions  Very “web friendly” for use with external systems, semantic mediation, URIs, XML format for interchange  “Non-experts” can build an ontology using Protégé  Architectural considerations: faceted search interface Tool support  Protégé  Sesame Triple Store, Jena Java API

14. Example RDF Statements “Balaji works at GFDL.” Curator meeting GFDL “18 Oct 2007” “19 Oct 2007” Balaji hasLocation worksAt starts ends

15. RDF XML Representation 18 Oct 2007 19 Oct 2007

16. ESG Ontology with Curator Extensions Protégé 4 beta: http://protege.stanford.edu/download/registered.html#p4http://protege.stanford.edu/download/registered.html#p4 Update Pizza Tutorial (HIGHLY RECOMMENDED) http://www.co-ode.org/resources/tutorials/ProtegeOWLTutorial-p4.0.pdf

17. XML/XML Schema What it is  Very widely accepted format for communication between applications, tag-based markup Source  W3C Standards Motivations  A standard implementation that modeling groups can adhere to (most will not be comfortable with RDF/OWL)  Can be output by modeling frameworks such as ESMF  “Use profiles” are small chunks of XML for specific purposes (part of the egg white?)

18. XML/XML Schema Tool support  XMLSpy, oXygen, Notepad... Query languages  XQuery, XPath  XSLT for transforming XML to other formats

19. SQL – Relational Databases (RDBMS) ANSI standard Motivations  Very mature technology  RDF/OWL and XML are likely NOT good solutions for long term storage  Fast querying  Large scale metadata storage

20. Representation Issues/Considerations What kinds of constraints do we need to precisely model the domain?  structural constraints vs. dynamic constraints What kinds of reasoning and query capabilities do the applications require? What role will the meta-model play? How do you keep consistency among several representations/notations?  What is the role of auto-generation?

21. Putting it all together... A prototype application developed this summer at NCAR in collaboration with ESMF and ESG:  ESMF modeling components become “self-describing”  Metadata is exported from an ESMF component in a standardized XML format (multiple conventions allowed)  The XML is ingested into ESG and exposed to the portal for users to search

22. Metadata Lifecycle

23. 1.ESMF component exports XML metadata 2.The XML is validated and harvested into a Java object representation 3.The Java objects are persisted to a relational database (RDBMS) 4.Metadata in the RDBMS is then harvested into RDF – a Semantic Web ontology language 5.The RDF is accessed by the ESG web portal for faceted search of the metadata

24. ESMF XML Output (example) …… Viewed as a simple “use-profile”

25. ESMF XML Output (example) ……

26. ESG Prototype Data Portal Faceted search Harvested component

27. ESG Prototype Data Portal

29. Demo of Dycore Portal http://dycore.ucar.edu/