An Overview: Ontology Concepts, Tools, Sample CEOP Ontology And Perspectives Rama Suresh Email:...
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Transcript of An Overview: Ontology Concepts, Tools, Sample CEOP Ontology And Perspectives Rama Suresh Email:...
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
underscores, not spaces.
Station Identifier
15 chars N/A Fill name with
underscores, not spaces.
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
1 char M See Flag values
V Wind Component f7.2 -999.99 m/s. See Equations
V Wind Component Flag
1 char M See Flag values
CEOPS Surface Meteorological and Radiation Data
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
1 char M See Flag values
Outgoing Shortwave f8.2 -999.99 W/m2
Outgoing Shortwave Flag
1 char M See Flag values
Incoming Longwave f8.2 -999.99 W/m2.
Incoming Longwave Flag
1 char M See Flag values
Outgoing Longwave f8.2 -999.99 W/m2.
Outgoing Longwave Flag
1 char M See Flag values
Net Radiation f8.2 -999.99 W/m2. See Equations
Net Radiation Flag 1 char M See Flag values
CEOPS Surface Meteorological and Radiation Data
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