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).

SensorML

• 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.

Ability of computer systems to exchange data with

unambiguous, shared meaning

Ability of computer systems to process a syntax and exchange

information

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.

SensorML

Identification Classification Keywords Capabilities Characteristics History References Documentation

Classify a Fast repetition rate fluorometer in SensorML to aid the rapid discovery of my sensors

<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> </sml:ClassifierList> </sml:classification> <sml:classification> <sml:ClassifierList> <!-- 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>

Find sensors that are classified as fluorometers

Section: Classification Term: Category, InstrumentType..? Vocabulary: ? Value: “%fluorometer%”

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

<sml:classfication> <sml:ClassifierList> <!-- Name of the manufacturer of the Sensor X --> <sml:classifier name=“InstrumentType"> <sml:Term > <sml:label>Instrument Type</sml:label> <sml:value> </sml:value> </sml:Term> </sml:identifier> <sml:IdentifierList> </sml:identification>

Classify a Fast repetition rate fluorometer in SensorML to aid the rapid discovery of my sensors

definition= "http://vocab.nerc.ac.uk/collection/W06/current/CLSS0002/">

http://vocab.nerc.ac.uk/collection/L05/current/353/

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

Application domain

Call Sign

ICES code

Long name

Manufacturer

Model name

Model Number

Serial number

Short name

UUID

Unique ID

Version

WMO platform number

Classification

Instrument Type

Platform Type

Keywords Capabilities

Accuracy

Damping ratio

Detection limit

Frequency

Measurement range

Operating depth

Precision

Resolution

Response time

Selectivity

Sensitivity

Survival depth

Characteristics

Data storage

Height

Housing material

Length

Weight

Width

History

Calibration

Decommissioning

Delivery

Deployment

Failure

LoanEnd

LoanStart

Loss

Maintenance

Recovery

RepairEnd

RepairStart

Upgrade

References

Data scientist

Manufacturer

Operator

Owner

PI

Technical Coordinator

Wiki SWE examples

Member post on the wiki

SSN ontology

SensorML examples

OpenGIS® SensorML Implementation

Specification

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 Tiiii

http://vocab.nerc.ac.uk/collection/W03/current/ SiiiiiML Hiiiiii Eiiii Tiiii

http://vocab.nerc.ac.uk/collection/W04/current/ SiiiiiML Ciiiiiiiii Siiiiii Tiiii

http://vocab.nerc.ac.uk/collection/W05/current/ SiiiiiML Ciiiiiiiiiiiii Siiiiii Tiiii

http://vocab.nerc.ac.uk/collection/W06/current/ SiiiiiML Ciiiiiiiiiiiii Siiiiii Tiiii

http://vocab.nerc.ac.uk/collection/W07/current/ SiiiiiML Iiiiiiiiiiiiii Siiiiii Tiiii

http://vocab.nerc.ac.uk/collection/W08/current/ SiiiiiML Ciiiiii Siiiiii Tiiii

Process

Member posts on the wiki a

suggestion/correction under a section

containing a title and a definition (alt label)

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

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/