Semantically enhancing SensorML with controlled vocabularies in the marine domain KOKKINAKI ALEXANDRA, BUCK JUSTIN, DARROCH LOUISE, JIRKA SIMON AND THE MARINE PROFILES FOR OGC SENSOR WEB ENABLEMENT STANDARDS TEAM Funded by SenseOCEAN (FP7/2007 2013 under grant agreement No. 61414) Bridges (Horizon 2020 under grant agreement No 635359)
Overview Introduction SensorML s flexibility Vocabularies Process Next steps Conclusion
Introduction The marine domain has started implementing Open Geospatial Consortium s (OGC) Sensor Web Enablement (SWE) standards Aim to: make all types of sensors, transducers and sensor data repositories discoverable, accessible and useable via the Web Include: Sensor Model Language (SensorML), Observations and Measurements (O&M), Sensor Planning Service (SPS), Transducer Markup Language (TML), Sensor Alert Service (SAS), Sensor Observation Service (SOS) and Web Notification Service (WNS).
Ability of computer systems to exchange data with unambiguous, shared meaning SensorML Ability of computer systems to process a syntax and exchange information The main objective is to enable interoperability, first at the syntactic level and later at the semantic level (by using ontologies and semantic mediation), so that sensors and processes can be better understood by machines, utilized automatically in complex workflows, and easily shared between intelligent sensor web nodes.
Characteristics SensorML flexible enough to describe all types of sensors Soft typing characteristic: pre-define in schema every possible property property types defined outside of the SensorML schema (typically within an online ontology) and then be used within SensorML as a value to the definition attribute.
Classify a Fast repetition rate fluorometer in SensorML to aid the rapid discovery of my sensors SensorML Identification Classification Keywords Capabilities Characteristics History References Documentation
<sml:classification> <sml:classifierlist> <!-- Instrument type of Fast Repetition Rate Fluorometer --> <sml:classifier name= InstrumentType"> <sml:term definition= "http://www.example.com/definitions.html#instrumenttype"> <sml:label>instrument Type</sml:label> <sml:value> active fluorometers </sml:value> </sml:term> </sml:classifier> Find sensors that are classified as </sml:classifierlist> fluorometers </sml:classification> Section: Classification Term: Category, InstrumentType..? <sml:classification> Vocabulary:? <sml:classifierlist> Value: %fluorometer% <!-- Instrument type of Fast Repetition Rate Fluorometer --> <sml:classifier name= Category"> <sml:term definition= "http://www.myexample.com/mydefinitions.html#category"> <sml:label>category</sml:label> <sml:value> flurometers </sml:value> </sml:term> </sml:classifier> </sml:classifierlist> </sml:classification>
Consequences Soft typing Different terms for the same meaning Variations in the meaning of the same term Terms not properly defined Terms not resolvable Many different ontologies with variations on the names of same terms Terms not mapped with each other Reduce interoperability and discoverability via the web.
SensorML ontology SensorML creators have created the SensorML ontology to list these terms, through the Marine Metadata Interoperability (MMI) project, which hosts an Ontology Registry and Repository hosting a number of small project specific controlled vocabularies. Since different communities require different terminologies, the ontology can fulfill only a subset of the required concepts.
Solution In order to achieve interoperability within and between various sensor communities, implementation of SensorML will require the definition of community specific semantics (within online dictionaries or ontologies) that can be utilized within the framework [OpenGIS Sensor Model Language (SensorML) Implementation Specification]
Marine Community SWE Marine Profiles 52 North Wiki for SWE Marine Profiles National Environmental Research Council (NERC) Vocabulary Server 2.0
SWE Marine profiles Group by partners from several projects and initiatives (AODN, BRIDGES, ENVRI+, EUROFLEETS /EUROFLEETS2, FixO3, FRAM, IOOS, Jerico/Jerico-Next, NeXOS, ODIP/ODIP II, RITMARE, SeaDataNet, SenseOcean, X-DOMES) Aim at developing marine profiles of OGC SWE standards to serve as a common basis for OGC implementations
Controlled Vocabularies and NVS2.0 Controlled vocabularies: In information science controlled vocabulary is a carefully selected list of words and phrases, which are used to tag units of information (document or work) so that they may be more easily retrieved by a search. NERC Vocabulary Server 2.0 (NVS2.0) provides access to lists of standardized terms machine and human readable W3C Simple Knowledge Organisation System (SKOS), RDF/XML Vocab Search, Vocab editor
Classify a Fast repetition rate fluorometer in SensorML to aid the rapid discovery of my sensors <sml:classfication> <sml:classifierlist> <!-- Name of the manufacturer of the Sensor X --> <sml:classifier name= InstrumentType"> <sml:term > definition= "http://vocab.nerc.ac.uk/collection/w06/current/clss0002/"> <sml:label>instrument Type</sml:label> <sml:value> http://vocab.nerc.ac.uk/collection/l05/current/353/ </sml:value> </sml:term> </sml:identifier> <sml:identifierlist> </sml:identification> Find sensors that are classified as fluorometers Section: Classification Term: InstrumentType Vocabulary: NVS2.0 Value: L05::353
Term values Observable property: NVS2.0 Vocabulary P01, P07 Instrument Type: NVS2.0 Vocabulary L05 Platform Type: NVS2.0 Vocabulary L06 Sensor Models: NVS2.0 Vocabulary L22 Roles: NVS2.0 Vocabularies G04, C86 Feature of Interest: NVS2.0 Vocabulary C19 Manufacturer: NVS2.0 Vocabularies L35, C75
Term Definitions: Initial Process Collected terms from the SWE examples SWE Marine wiki Identified common terms under each section containing title, definition, alt label Post on the wiki Members add/suggest corrections on the wiki Revised and submit to the VMG Published on the web
SensorML Identification Classification Keywords Capabilities Characteristics History References Application domain Instrument Type Accuracy Data storage Calibration Data scientist Call Sign Platform Type Damping ratio Height Decommissioning Manufacturer ICES code Detection limit Housing material Delivery Operator Wiki SWE examples Long name Frequency Length Deployment Owner Member post on the wiki Manufacturer Measurement range Weight Failure PI SSN ontology Model name Operating depth Width LoanEnd Technical Coordinator SensorML examples Model Number Precision LoanStart OpenGIS SensorML Implementation Specification Serial number Resolution Loss Short name Response time Maintenance UUID Selectivity Recovery Unique ID Sensitivity RepairEnd Version Survival depth RepairStart WMO platform number Upgrade
NVS collections for SensorML Each SensorML section constitutes a vocabulary=collection in NVS Described in SKOS and RDF/XML Holds a unique URI URI pattern: http://vocab.nerc.ac.uk/collection/xxx/current/ Each Collection consists of several terms=concepts Each term Holds a unique URI Resolves to RDF/XML URI pattern: http://vocab.nerc.ac.uk/collection/xxx/current/code/
URI http://vocab.nerc.ac.uk/collection/w03/current/ T itle SensorML History Event Types http://vocab.nerc.ac.uk/collection/w04/current/ SensorML Capability Section Term s http://vocab.nerc.ac.uk/collection/w05/current/ SensorML Characteristic Section Term s http://vocab.nerc.ac.uk/collection/w06/current/ SensorML Classification Section Term s http://vocab.nerc.ac.uk/collection/w07/current/ SensorML Identification Section Term s http://vocab.nerc.ac.uk/collection/w08/current/ SensorML Contact Section Term s
Process Member posts on the wiki a suggestion/correction under a section containing a title and a definition If other members do not disagree or Agree it is submitted for revision Revised and posted on the wiki to get final agreement Submitted to the VMG and published on the web (alt label)
Where next.. External mappings to the SensorML ontology Internal mappings to NVS2.0 terms Process a list of terms that have been added on the wiki
Conclusions SensorML s soft typing characteristic different versions of sensor descriptions not interoperable less discoverable Formalization of the required terms Publication in the form of controlled vocabularies served by NVS2.0 governed by group maintained by British Oceanographic Data Centre (BODC)
Acknowledgment This work is funded by the European projects SenseOCEAN (FP7/2007 2013 under grant agreement No. 61414) Bridges (European Union's Horizon 2020 research and innovation programme under grant agreement No 635359) Supported Ocean Data Interoperability Platform (ODIP) Supported by the National Environmental Research Council (NERC) National Capability (NC) funding for NC-services, facilities and data (NC-SFD).
Useful Links NVS2.0 SOAP service: http://vocab.nerc.ac.uk/vocab2.wsdl NVS2.0 RESTFul interface http://vocab.nerc.ac.uk/collection/ NVS2.0 SPARQL endpoint http://vocab.nerc.ac.uk/sparql/ NVS2.0 SensorML collections http://vocab.nerc.ac.uk/collection/w03/current/ http://vocab.nerc.ac.uk/collection/w04/current/ http://vocab.nerc.ac.uk/collection/w05/current/ http://vocab.nerc.ac.uk/collection/w06/current/ http://vocab.nerc.ac.uk/collection/w07/current/ http://vocab.nerc.ac.uk/collection/w08/current/