Mini Ontologies and Metadata Expressions Todd King1 and Bernd Ritschel2

(1) Department of Earth and Space Sciences, UCLA, Los Angeles, CA 90095. (2) GFZ, German Research Centre for Geosciences, Postdam, Germany.

Abstract Ontologies come in many forms and with a wide range of detail and specificity. Of particular interest in the realm of science are classification schemes or taxonomies. Within general science domains there may be multiple taxonomies. Each taxonomy can be represented as a very narrowly defined domain ontology. We call such ontologies "mini ontologies". Since mini ontologies are very modular and portable they can be used in a variety of context. To illustrate the generation and use of mini ontologies we show how enumerations which may part of an existing data model, like SPASE *Region enumerations, can be modeled as a mini ontology. We show how such ontologies can be transformed to generate metadata expressions which can be readily used in different operational context, for example in the <meta> tag of a web page. We define a set of context specific transforms for commonly used metadata expressions which can preserve the semantic information in a mini ontology and describe how such expressions are reversible. The sharing and adoption of mini ontologies can significantly enhance the discovery and use of related data resources within a community. We look at several cases where this is true with a special focus on the international ESPAS project.

IN11A-1512

An ontology is a set of precise descriptive statements about some part of the world (usually referred to as the domain of interest or the subject matter of the ontology).

- Owl 2 primer

Ontologies

Linked Ontology Vocabularies catalogs 381 vocabularies. About 6 vocabularies form a core: DCMI Terms, FOAF, CC_REL, SIOC, DOAP.

http://lov.okfn.org/dataset/lov/index.html

An information model in software engineering is a representation of concepts and the relationships, constraints, rules, and operations to specify data semantics for a chosen domain of discourse.

- Wikipedia

Information Models

Some widely used information models in space physics are: SPASE: http://spase-group.org/

Connections to diverse resources, including those outside the domain of the information, model ,is enabled with when concepts are expressed (or mapped) to common base ontologies.

Ontology tools can be used to create information models which are have both well controlled vocabularies and rich semantics.

An ontology is a set of precise descriptive statements about some part of the world (usually referred to as the domain of interest or the subject matter of the ontology).

- Owl 2 primer

Metadata Expressions

Existing Models

Make Models More Module

Semantics

Enhance the semantics

While adding semantics to some existing models its necessary to make the implicit semantics explicit and to use common ontologies where appropriate.

SPASE Observed Region as an example

Metadata Expressions

Express metadata in multiple forms.

Most existing information models in space physics are monoloithic and do not connect with other models.

Terms AccessInformation AccessRights AccessURL Acknowledgement Address AlternateName Annotation AnnotationType Association AssociationID AssociationType AtomicNumber Availability AxisLabel AzimuthalAngleRange BandName Bin Cadence Catalog Caveats Checksum ClassificationMethod ConfidenceRating Contact CoordinateRepresentation CoordinateSystem CoordinateSystemName DataExtent Description DisplayCadence DisplayData DisplayType Document DocumentType Element Elevation Email Encoding EnergyRange ExpirationDate Exposure Extension FaxNumber Field FieldQuantity FillValue Format FrequencyRange Granule HashFunction HashValue High ImageURL Index InformationURL InputResourceID Instrument InstrumentID InstrumentType InvestigationName Keyword Language Latitude Location Longitude Low MIMEType MeasurementType MirrorURL Mixed MixedQuantity Name Note NumericalData ObservationExtent Observatory ObservatoryGroupID ObservatoryID ObservatoryRegion ObservedRegion OperatingSpan OrganizationName Parameter ParameterEntity ParameterKey ParentID Particle ParticleQuantity ParticleType Per Person PersonID PersonName PhenomenonType PhoneNumber PolarAngleRange PriorID ProcessingLevel ProductKey ProviderProcessingLevel ProviderResourceName ProviderVersion Qualifier Quantity Registry RelativeStopDate ReleaseDate RenderingAxis RenderingHints Repository RepositoryID ResourceEntity ResourceHeader ResourceID ResourceName Role ScaleMax ScaleMin ScaleType Service Set Size Source SourceType Spase SpectralRange StartDate StartLocation StopDate StopDateEntity StopLocation Structure Support SupportQuantity TemporalDescription TimeSpan URL Units UnitsConversion ValidMax ValidMin ValueFormat Version Wave WaveQuantity WaveType WavelengthRange

Enumerations enumAccessRights enumAnnotationType enumAssociationType enumAvailability enumClassificationMethod enumComponent enumConfidenceRating enumCoordinateRepresentation enumCoordinateSystemName enumDirectionAngle enumDisplayType enumDocumentType enumEarth enumEncoding enumFieldQuantity enumFormat enumHardcopy enumHashFunction enumHeliosphere enumInstrumentType enumIntegral enumIonosphere enumMagnetosphere enumMeasurementType enumMixedQuantity enumNearSurface enumParticleQuantity enumParticleType enumPhenomenonType enumProcessingLevel enumProjection enumQualifier enumRegion enumRenderingAxis enumRole enumScaleType enumSourceType enumSpectralRange enumSun enumSupportQuantity enumText enumVersion enumWaveQuantity enumWaveType enumWaves

Complex Types AccessInformation AccessURL Annotation Association AzimuthalAngleRange Bin Catalog Checksum Contact CoordinateSystem DataExtent DisplayData Document Element EnergyRange Extension Field FrequencyRange Granule InformationURL Instrument Location Mixed NumericalData ObservationExtent Observatory OperatingSpan Parameter Particle Person PolarAngleRange Registry RenderingHints Repository ResourceHeader Service Source Spase Structure Support TemporalDescription TimeSpan Wave WavelengthRange

PDS: http://pds.nasa.gov/pds4

Terms: 147 Classes: 44 Enumerations: 45 Data Types: 1

pds:Agency/ppds:Update_Entry/pds:date_time pds:Update_Entry/pds:description pds:Update_Entry/pds:full_name pds:Vector/pds:Vector_Component pds:Vector/pds:data_type pds:Vector/pds:description pds:Vector/pds:local_identifier pds:Vector/pds:name pds:Vector/pds:reference_frame_id pds:Vector/pds:type pds:Vector/pds:vector_components pds:Vector_Cartesian_3/pds:reference_frame_id pds:Vector_Cartesian_3/pds:x pds:Vector_Cartesian_3/pds:y pds:Vector_Cartesian_3/pds:z pds:Vector_Cartesian_3_Acceleration/pds:refer… pds:Vector_Cartesian_3_Acceleration/pds:x pds:Vector_Cartesian_3_Acceleration/pds:y pds:Vector_Cartesian_3_Acceleration/pds:z pds:Vector_Cartesian_3_Pointing/pds:referenc… pds:Vector_Cartesian_3_Pointing/pds:x pds:Vector_Cartesian_3_Pointing/pds:y pds:Vector_Cartesian_3_Pointing/pds:z pds:Vector_Cartesian_3_Position/pds:referenc… pds:Vector_Cartesian_3_Position/pds:x pds:Vector_Cartesian_3_Position/pds:y pds:Vector_Cartesian_3_Position/pds:z pds:Vector_Cartesian_3_Velocity/pds:referen.c… pds:Vector_Cartesian_3_Velocity/pds:x pds:Vector_Cartesian_3_Velocity/pds:y pds:Vector_Cartesian_3_Velocity/pds:z pds:Vector_Component/pds:description pds:Vector_Component/pds:name pds:Vector_Component/pds:sequence_number pds:Vector_Component/pds:unit pds:Vector_Component/pds:value pds:Volume_PDS3/pds:archive_status pds:Volume_PDS3/pds:archive_status_note pds:Volume_PDS3/pds:curating_node_id pds:Volume_PDS3/pds:description pds:Volume_PDS3/pds:medium_type pds:Volume_PDS3/pds:publication_date pds:Volume_PDS3/pds:volume_de_fullname pds:Volume_PDS3/pds:volume_format pds:Volume_PDS3/pds:volume_id pds:Volume_PDS3/pds:volume_name pds:Volume_PDS3/pds:volume_set_id pds:Volume_PDS3/pds:volume_size pds:Volume_PDS3/pds:volume_version_id pds:Volume_Set_PDS3/pds:description pds:Volume_Set_PDS3/pds:volume_series_name pds:Volume_Set_PDS3/pds:volume_set_id pds:Volume_Set_PDS3/pds:volume_set_name pds:Volume_Set_PDS3/pds:volumes pds:XML_Schema/pds:description pds:XML_Schema/pds:local_identifier pds:XML_Schema/pds:name pds:XML_Schema/pds:object_length pds:XML_Schema/pds:offset pds:XML_Schema/pds:parsing_standard_id pds:Zip/pds:container_type pds:Zip/pds:description

Terms:885 Classes: 201 Enumerations: 74 Data Types: 102

Complex Types pds:Agency pds:Alias pds:Alias_List pds:Archival_Information_Package pds:Array pds:Array_1D pds:Array_2D pds:Array_2D_Image pds:Array_2D_Map pds:Array_2D_Spectrum pds:Array_3D pds:Array_3D_Image pds:Array_3D_Movie pds:Array_3D_Spectrum pds:Axis_Array pds:Band_Bin pds:Band_Bin_Set pds:Bundle pds:Bundle_Member_Entry pds:Byte_Stream pds:Checksum_Manifest pds:Citation_Information pds:Collection pds:Context_Area pds:DD_Association pds:DD_Association_External pds:DD_Attribute pds:DD_Attribute_Full pds:DD_Class pds:DD_Class_Full pds:DD_Permissible_Value pds:DD_Permissible_Value_Full pds:DD_Value_Domain pds:DD_Value_Domain_Full pds:DIP_Deep_Archive pds:Data_Set_PDS3 pds:Discipline_Area pds:Display_2D_Image pds:Dissemination_Information_Package pds:Document pds:Document_File pds:Document_Format pds:Document_Format_Set pds:Element_Array pds:Encoded_Binary pds:Encoded_Byte_Stream pds:Encoded_Header pds:Encoded_Image pds:External_Reference pds:External_Reference_Extended

pds:XML_Schema pds:Zip pds:altitude pds:aperture pds:band_width pds:center_wavelength pds:field_length pds:field_location pds:file_size pds:group_length pds:group_location pds:maximum_field_length pds:maximum_record_length pds:object_length pds:offset pds:publication_date pds:record_length pds:reference_frame_id pds:solar_longitude pds:start_date_time pds:stop_date pds:stop_date_time

Terms pds:Agency/pds:description pds:Agency/pds:name pds:Alias/pds:alternate_id pds:Alias/pds:alternate_title pds:Alias/pds:comment pds:Alias_List/pds:Alias pds:Archival_Information_Package/pds:description pds:Array/pds:Axis_Array pds:Array/pds:Element_Array pds:Array/pds:Object_Statistics pds:Array/pds:Special_Constants pds:Array/pds:axes pds:Array/pds:axis_index_order pds:Array/pds:description pds:Array/pds:offset pds:Array_1D/pds:Axis_Array pds:Array_1D/pds:Element_Array pds:Array_1D/pds:Object_Statistics pds:Array_1D/pds:Special_Constants pds:Array_1D/pds:axes pds:Array_1D/pds:axis_index_order pds:Array_1D/pds:description pds:Array_1D/pds:local_identifier pds:Array_1D/pds:name pds:Array_1D/pds:offset pds:Array_2D/pds:Axis_Array pds:Array_2D/pds:Element_Array pds:Array_2D/pds:Object_Statistics pds:Array_2D/pds:Special_Constants pds:Array_2D/pds:axes pds:Array_2D/pds:axis_index_order pds:Array_2D/pds:description pds:Array_2D/pds:local_identifier pds:Array_2D/pds:name pds:Array_2D/pds:offset pds:Array_2D_Image/pds:Display_2D_Image pds:Array_2D_Map/pds:Display_2D_Image pds:Array_2D_Spectrum/pds:Display_2D_Image pds:Array_3D/pds:Axis_Array pds:Array_3D/pds:Element_Array pds:Array_3D/pds:Object_Statistics pds:Array_3D/pds:Special_Constants pds:Array_3D/pds:axes pds:Array_3D/pds:axis_index_order pds:Array_3D/pds:description pds:Array_3D/pds:local_identifier pds:Array_3D/pds:name pds:Array_3D/pds:offset pds:Array_3D_Image/pds:Axis_Array pds:Array_3D_Image/pds:Element_Array pds:Array_3D_Image/pds:Object_Statistics pds:Array_3D_Image/pds:Special_Constants pds:Array_3D_Image/pds:axes pds:Array_3D_Image/pds:axis_index_order pds:Array_3D_Image/pds:description pds:Array_3D_Image/pds:local_identifier pds:Array_3D_Image/pds:name pds:Array_3D_Image/pds:offset pds:Array_3D_Movie/pds:Axis_Array pds:Array_3D_Movie/pds:Element_Array pds:Array_3D_Movie/pds:Object_Statistics pds:Array_3D_Movie/pds:Special_Constants pds:Array_3D_Movie/pds:axespds:XML_Schema pds:Zip pds:altitude pds:aperture pds:band_width pds:center_wavelength pds:field_length

Simple Types pds:ASCII_AnyURI pds:ASCII_Boolean pds:ASCII_DOI pds:ASCII_Date pds:ASCII_Date_DOY pds:ASCII_Date_Time pds:ASCII_Date_Time_DOY pds:ASCII_Date_Time_UTC pds:ASCII_Date_Time_YMD pds:ASCII_Date_YMD pds:ASCII_Directory_Path_Name pds:ASCII_File_Name pds:ASCII_File_Specification_Name pds:ASCII_Integer pds:ASCII_LID pds:ASCII_LIDVID pds:ASCII_LIDVID_LID pds:ASCII_MD5_Checksum pds:ASCII_NonNegative_Integer pds:ASCII_Numeric_Base16 pds:ASCII_Numeric_Base2 pds:ASCII_Numeric_Base8 pds:ASCII_Real pds:ASCII_Short_String_Collapsed pds:ASCII_Short_String_Preserved pds:ASCII_String pds:ASCII_Text_Collapsed pds:ASCII_Text_Preserved pds:ASCII_Time pds:ASCII_VID pds:UTF8_Short_String_Collapsed pds:UTF8_Short_String_Preserved pds:UTF8_String pds:UTF8_Text_Preserved pds:Units_of_Acceleration pds:Units_of_Amount_Of_Substance pds:Units_of_Angle pds:Units_of_Angular_Velocity pds:Units_of_Area pds:Units_of_Frame_Rate pds:Units_of_Frequency pds:Units_of_Length pds:Units_of_Map_Scale pds:Units_of_Mass pds:Units_of_Misc pds:Units_of_None pds:Units_of_Optical_Path_Length pds:Units_of_Pressure pds:Units_of_Radiance pds:Units_of_Rates pds:Units_of_Solid_Angle pds:Units_of_Storage pds:Units_of_Temperature pds:Units_of_Time pds:Units_of_Velocity pds:Units_of_Voltage pds:Units_of_Volume pds:altitude_WO_Units pds:aperture_WO_Units pds:archive_status_note pds:axes pds:band_number pds:band_width_WO_Units pds:bit_fields pds:center_wavelength_WO_Units pds:detector_number pds:elements pds:field_length_WO_Units pds:field_location_WO_Units pds:field_number pds:fields pds:file_size_WO_Units pds:files pds:filter_number pds:grating_position pds:group_length_WO_Units pds:group_location_WO_Units pds:groups pds:institution_name pds:ldd_version_id pds:local_mean_solar_time pds:local_true_solar_time pds:maximum_field_length_WO_Units pds:maximum_record_length_WO_Units pds:md5_checksum pds:nil_reason pds:nil_reason_list pds:object_length_WO_Units pds:offset_WO_Units pds:original_band pds:record_length_WO_Units pds:records pds:repetitions pds:sequence_number pds:solar_longitude_WO_Units pds:standard_deviation pds:start_bit pds:stop_bit pds:telescope_latitude_WO_Units pds:telescope_longitude_WO_Units pds:version_id pds:volumes

Simple Types typeSequence

Enumerations • -32752, 1, 3, 5, FF7FFFFA, FFEFFFF • -32764, 255, 4, 65535, FF7FFFFF, F • -32765, 255, 3, 65534, FF7FFFFE, F • -32766, 0, 2, FF7FFFFD, FFFDFFFF • -32767, 1, 16#FF7FFFFC#, 16#FFFEFF • 254, 32767, 65522 • 7-Bit ASCII Text, CDF 3.4 ISTP/IAC • 7-Bit ASCII Text, Encapsulated Pos • Acceleration, Pointing, Position, • Accelerometer, Alpha Particle Dete • ADDRESS, ANGLE, ATTRIBUTE, BIT, CH • Aerial survey - North American (19 • Affiliate, Data Provider, Manager, • Altimetry, Astrometry, Count, E/B- • Archive, Supplemental • ARCHIVED, ARCHIVED_ACCUMULATING, I • Artificial Illumination, Instrumen • ASCII_AnyURI, ASCII_Boolean, ASCII • ASCII_AnyURI, ASCII_Boolean, ASCII • ASCII_AnyURI, ASCII_Boolean, ASCII • ASCII_AnyURI, ASCII_Boolean, ASCII • Asteroid, Comet, Dust, Dwarf Plane • atm, geo, img, naif, ops, pds, ppi • attribute_of, component_of, extens • Binary, Character • BOOLEAN, INTEGER, NAME, NUMERIC, R • Browse, Calibration, Context, Data • browse_to_data, browse_to_thumbnai • bundle_has_browse_collection, bund • bundle_to_errata, bundle_to_docume • Calibrated, Derived, Partially Pro • Calibration, Checkout, Engineering • carriage-return line-feed • CCSDS Communication Protocols • CK, DBK, DSK, EK, FK, IK, LSK, MK, • collection_to_resource, collection • comma, horizontal tab, semicolon, • ComplexLSB16, ComplexLSB8, Complex • context_to_associate, instrument_h • data_to_resource, data_to_calibrat • data_to_target, collection_to_targ • data_to_update, collection_to_upda • document_to_associate, document_to • Down, Up • Dust, Electric Field, Electrons, F • Earth Based, Rover, Spacecraft • Engineering, Geosciences, Headquar • Engineering, Geosciences, Imaging, • English, Russian • European Space Agency, National Ae • Exponential, Linear, Logarithmic • GIF, J2C, JPEG, PDF, PDF/A, PNG, T • GZIP, LZIP, TAR, ZIP • ICRF, MOON_ME_DE421 • Individual Investigation, Mission, • Information.Agency, Information.In • is_instrument, is_instrument_host, • Laboratory, Observatory • Last Index Fastest • Line, Sample • MD5Deep 4.n • multiple file, single file • package_has_collection, package_ha • package_has_collection, package_ha • PDS3, PDS4 • Primary, Secondary • Product_AIP, Product_Attribute_Def • Product_Attribute_Definition,Produ • Schematron ISO/IEC 19757-3:2006, X • SignedBitString, UnsignedBitString • SPICE, Spacecraft Telemetry • Units_of_Acceleration, Units_of_Am • Units_of_Amount_Of_Substance, Unit • WADL, WSDL 2.n

We need to: We need to: We need to:

Note: The PDS4 information model was designed using off-the-shelf ontology tools. SPASE was designed with an ad hoc tool.

When unique concepts are needed, model each concept as a separate "mini"-ontology.

Implicit in original IM

Reuse

Different platforms require metadata in different forms. Semantic languages are designed for machine. Using semantic languages for information models , while useful, requires transforming to other forms of expression. Some of the most common forms are XML Schema, Schematron and HTML documents. Other useful formats are expressing enumerations in concise, single line formats such as dot or XPath notation.

SPASE Observed Region in Turtle as an example

:Earth rdf:type owl:Class ; rdfs:subClassOf :Body ; owl:disjointWith :Uranus , :Pluto , :Jupiter , :Mercury … owl:equivalentClass [ rdf:type owl:Restriction ; owl:onProperty :has ; owl:someValuesFrom :Magnetosphere ] ; owl:equivalentClass [ rdf:type owl:Restriction ; owl:onProperty :has ; owl:someValuesFrom :Surface ] ; owl:equivalentClass [ rdf:type owl:Restriction ; owl:onProperty :has ; owl:someValuesFrom :NearSurface ] . :Region rdf:type owl:Class ; rdfs:subClassOf owl:Thing ; owl:equivalentClass [ rdf:type owl:Restriction ; owl:onProperty :has ; owl:someValuesFrom :Uranus ] ; owl:equivalentClass [ rdf:type owl:Restriction ; owl:onProperty :has ; owl:someValuesFrom :Interstellar ] ; owl:equivalentClass [ rdf:type owl:Restriction ; owl:onProperty :has ; owl:someValuesFrom :Comet ] ;

Asteroid Comet Earth Earth.Magnetosheath Earth.Magnetosphere Earth.Magnetosphere.Magnetotail Earth.Magnetosphere.Main Earth.Magnetosphere.Polar Earth.Magnetosphere.Radiation Belt Earth.Near Surface Earth.Near Surface.Atmosphere Earth.Near Surface.Auroral Region Earth.Near Surface.Equatorial Region Earth.Near Surface.Ionosphere Earth.Near Surface.Ionosphere.D-Region Earth.Near Surface.Ionosphere.E-Region Earth.Near Surface.Ionosphere.F-Region Earth.Near Surface.Ionosphere.Topside Earth.Near Surface.Mesosphere Earth.Near Surface.Plasmasphere Earth.Near Surface.Polar Cap Earth.Near Surface.South Atlantic Anomaly Region Earth.Near Surface.Stratosphere Earth.Near Surface.Thermosphere Earth.Near Surface.Troposphere Earth.Surface Heliosphere Heliosphere.Heliosheath Heliosphere.Inner Heliosphere.Near Earth Heliosphere.Outer Heliosphere.Remote 1AU Interstellar Jupiter Mars Mercury Neptune Pluto Saturn Sun Sun.Chromosphere Sun.Corona Sun.Interior Sun.Photosphere Sun.Transition Region Uranus Venus

Conclusions The development of the SPASE information using ontology principals, followed by the development of the PDS4 information model using ontology editors has demonstrated the effectiveness of the approach. With appropriate transforms the models can be expressed in multiple platform specific forms. Refactoring current information models to align with common base ontologies will enable expanded use and further leverage each information model.

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