An Overview: Ontology Concepts, Tools, Sample CEOP Ontology And Perspectives Rama Suresh Email: [email protected] NASA/MTECH CEOS WGISS Joint Subgroup

An Overview: Ontology Concepts, Tools, Sample CEOP Ontology And Perspectives

Rama Suresh Email: [email protected]

NASA/MTECH

CEOS WGISS Joint Subgroup Meeting Tromso Norway, May 11, 2004

Background

Ontology Concepts

Ontology tools and Protégé

CEOP background and Sample Ontology

Perspectives

EO Projects

Outline

BackgroundBackgroundCurrent Web is a powerful means for collaboration

between people, broadcasting and publishing information worldwide

The next generation web will extend collaborations between to computers...

Machines become capable of analyzing all the data on the Web – the content, links, and transactions between people and computers…

When it arrives, the day-to-day mechanisms of trade, bureaucracy, and our daily lives will be handled by machines talking to machines, leaving humans to provide the inspiration and intuition…

The intelligent "agents" people have touted for ages will finally materialize…

This machine-understandable Web will come about through the implementation of a series of technical advancements and social agreements that are now beginning…

Weaving the Web, Tim Berners-Lee, with Mark Fischetti. Harper San Francisco, October 1999

Formula for computer “conversation”Formula for computer “conversation”

Meaning = Ontology + representation + constraints

Conclusions = Inference engine(new knowledge, experience, context)

Rama BotMust find low priced 3star hotel in Tromso,

accurate 3 day Weather forecast for Tromso from

May 10-12.

Discovering the new semantic worldsDiscovering the new semantic worlds

• Future – ubiquitous, machine-to-machine collaboration

• Today – increasing consistency of metadata management for some localized uses

cite

What Is An Ontology

An ontology is an explicit description of a domain:• Concepts • properties and attributes of concepts• constraints on properties and attributes• Individuals (often, but not always)

An ontology defines • a common vocabulary• a shared understanding

Why Develop an Ontology?Why Develop an Ontology?

• To share common understanding of the structure of information – among people– among software agents

• To enable reuse of domain knowledge– to avoid “re-inventing the wheel”– to introduce standards to allow

interoperability

Building Ontology

1. Acquire domain knowledge

- Assemble appropriate information resources and expertise in the domain of interest - These definitions must be collected so that they can be expressed in a common language selected for the ontology

2. Organize the ontology- Design the overall conceptual structure of the domain. - Identify the domain's principal concrete concepts and their properties, and their relationships among the concepts

3. Flesh out the ontology- Add concepts, relations, and individuals to the level of detail

necessary to satisfy the purposes of the ontology.

4. Check your work- Reconcile syntactic, logical, and semantic inconsistencies among the ontology elements.

- Consistency checking may also involve automatic classification that defines new concepts based on individual properties and class relationships.

5. Commit the ontology- Incumbent on any ontology development effort is a final verification of the ontology by domain experts

- Subsequent commitment of the ontology by publishing it within its intended deployment environment.

Building Ontology

• Ontology building today is a fragmented practice. • Proliferation of logic languages• Information models that have combined to yield even

more ontology forms and editing environments

• These tools and methodologies, along with the ontologies built with them, generally exist without proven interoperability

• Challenges for establishing methods to integrate ontology components with enterprise information systems and standards

Ontology Issues

Software tools are available to accomplish most aspects of ontology development. While ontology editors are useful during each step outlined above, other types of ontology building tools are also needed along the way.

More than 50 tools have been identified for building and integrating ontologies: Commercial, public domain and Academic projects

http://xml.com/2002/11/06/Ontology_Editor_Survey.html

Protégé is one of the tools described in the survey.

Ontology Tools Survey

Protégé-2000Protégé-2000

• An extensible and customizable toolset for constructing knowledge bases (KBs) and for developing applications that use these KBs

• Outstanding features– Automatic generation of graphical-user interfaces,

based on user-defined models, for acquiring domain instances

– Extensible knowledge model and architecture – Scalability to very large knowledge bases

Protégé-2000

• Java based graphical ontology-development tool• Supports a rich knowledge model• Open-source and freely available • Large user base• Easy to use

Some other available tools:• Ontolingua and Chimaera• OntoEdit• OilEd• OWL plug in

Protégé system development Protégé system development methodologymethodology Protégé-2000

support

determinescope

considerreuse

enumerateterms

defineclasses

defineproperties

defineconstraints

createinstances

In reality - an iterative process:

determinescope

considerreuse

enumerateterms

defineclasses

considerreuse

enumerateterms

defineclasses

defineproperties

createinstances

defineclasses

defineproperties

defineconstraints

createinstances

defineclasses

considerreuse

defineproperties

defineconstraints

createinstances

GUI ComponentsGUI Components

• Tabs partition different work areas– Classes tab for defining and editing classes– Forms tab for custom-tailoring GUI forms for defining and editing

instances– Instances tab for defining and editing instances– Classes & Instances tab for working with both classes and

instances• Widgets for creating, editing, and viewing values of a slot

(or a group of slots)– Text-field or text-area widget for a slot with string value type– Diagram widget for set of slots defining a graph– Slot widgets check facet constraint violations (red rectangles)

• Buttons and menus for performing operations

Classes, slots,facets and instance

are all frames

Protégé InformationProtégé Information

• Protégé web site: http://protege.stanford.edu– Documentation– User’s Guide– Tutorial– protege-discussion mailing list– Ontology library

• Contributed ontologies and plugins

A Sample Ontology for CEOP In Situ Data

Why CEOP In Situ data?• Global level significant involvement and commitment• In situ data is relatively simple

What will it do?Will improve resource discovery and create an open interface based on standards that will include large number of users.

What are the next steps?Build an ontology for CEOP involving CEOP and CEOS community that could potentially lead to a EO semantic web

The Coordinated Enhanced Observing Period (CEOP) was originally envisioned as a major step towards bringing together the research activities in the GEWEX Hydrometeorology Panel (GHP) and is being developed and implemented within the Global Energy and Water Cycle Experiment (GEWEX) of the World Climate Research Program (WCRP)

CEOP Data sets

• Satellite Data TERRA, AQUA, ENVISAT and ADEOS-II), in addition to TRMM, LANDSAT, NOAA-K series and other operational satellites

• Observation Data (In Situ Data)

• Model Output Data

http://www.ceop.net/

CEOP

Worldwide Reference Sites

Primary and ancillary data sets

Each Reference site has four data sets for each station that is a part of the Reference Site

• Surface Meteorological and Radiation Data set• Flux Data Set • Soil Temperature and Soil Moisture Data Set• Meteorological Tower Data Set

Source JAXA Metadata paper – Ben Burford

CEOP In Situ Data

Parameter Format Missing Value

Final Units, Equations, Notes

UTC Nominal Date/Time

16 chars N/Ayyyy/mm/dd HH:MM,

where MM is 00 or 30, only

UTC Actual Date/Time

16 chars N/A yyyy/mm/dd HH:MM

CSE Identifier 10 chars N/A Fill name with

underscores, not spaces.

Reference Site Identifier

15 chars N/A Fill name with


Station Identifier

15 chars N/A Fill name with


Latitude f10.5 -99.99999decimal degrees.

South is negative.

Longitude f11.5 -999.99999decimal degrees. West

is negative.

Elevation f7.2 -999.99 meters

CEOPS Surface Meteorological and Radiation Data

Station Pressure f7.2 -999.99 hPa (mb).

Station Pressure Flag 1 char M See Flag values

Air Temperature f7.2 -999.99 Celsius.

Air Temperature Flag 1 char M See Flag values

Dew Point Temperature

f7.2 -999.99 Celsius. See Equations

Dew Point Temperature Flag

1 char M See Flag values

Relative Humidity f7.2 -999.99 percent. See Equations

Relative Humidity Flag 1 char M See Flag values

Specific Humidity f7.2 -999.99 g/kg. See Equations

Specific Humidity Flag 1 char M See Flag values

Wind Speed f7.2 -999.99 m/s. See Equations

Wind Speed Flag 1 char M See Flag values

Wind Direction f7.2 -999.99 degrees. See Equations

Wind Direction Flag 1 char M See Flag values

U Wind Component f7.2 -999.99 m/s. See Equations

U Wind Component Flag


V Wind Component f7.2 -999.99 m/s. See Equations

V Wind Component Flag



Precipitation f7.2 -999.99millimeters. Incremental precipitation over the previous 30 minutes.

Precipitation Flag 1 char M See Flag values

Snow Depth f7.2 -999.99 centimeters.

Snow Depth Flag 1 char M See Flag values

Incoming Shortwave f8.2 -999.99 W/m2.

Incoming Shortwave Flag


Outgoing Shortwave f8.2 -999.99 W/m2

Outgoing Shortwave Flag


Incoming Longwave f8.2 -999.99 W/m2.

Incoming Longwave Flag


Outgoing Longwave f8.2 -999.99 W/m2.

Outgoing Longwave Flag


Net Radiation f8.2 -999.99 W/m2. See Equations

Net Radiation Flag 1 char M See Flag values


What can we do with it?

We can build autonomous agents or software to fetch information

Bring sites collecting data for certain period of time

Bring data sets with values for temperature ranging from degree Celsius to…..

Bring sites that have data parameters…….

CEOS 17th Plenary Recommendation

“CEOS space agency members need to develop information systems

with more integrated catalog, search, ordering and retrieval mechanism. It is recommended that the CEOS WGISS study how to develop this incrementally for particular application fields- building on experience gained in developing such capabilities with CEOP – and to report on its findings to the 2004 Plenary”

Building an Ontology for CEOP and Earth observation data is one step in this direction.

This could potentially lead to EO Semantic web that will help Users in faster and efficient resource discovery

Effective use of these technologies could potentially lead to an integrated catalog, search, ordering and retrieval mechanism

Perspectives

SWEET – NASA JPLhttp://sweet.jpl.nasa.gov/

GEON – University of San Diegowww.geongrid.org

UK Met Office

GCMD, ECHO and ESML

Other Earth Science Ontology Projects

Documents

An Overview: Ontology Concepts, Tools, Sample CEOP Ontology And Perspectives Rama Suresh Email: [email protected] NASA/MTECH CEOS WGISS Joint Subgroup