Event dashboard: Capturing user-defined semantics for event detection over real-time sensor data...

Event dashboard: Capturing user-defined semantics for event detection over real-time sensor data

CSIRO LAND AND WATER

Jonathan Yu | Research engineerEnvironmental Information Systems, CLW Highett

22 October 2013

Performing event detection over real-time sensor data using ontology-driven approaches | Jonathan Yu

1. Background: Event detection over real-time sensor data

2. Capturing machine readable semantics – ontologies

3. Event dashboard: Capturing user-defined semantics

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Outline





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Outline


Water quality issues...

Example events in this domain:• Total nitrogen conc. in a river > X mg/L• Dissolved oxygen conc. at sensor < Y mg/L

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Sensor middleware - Global Sensor Network (GSN)

WQ Weather Flow

Sensor Network

GSN

Virtual Sensor (WQ)

Virtual Sensor(Flow)

Virtual Sensor (Aggr.)

End users

User Interface

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Existing workflow: real-time event detection

High level entry for an end user e.g. Scientists and managers• Inefficient

Knowledge hidden behind code or in people’s heads, i.e. implicit semantics• Barrier for reusability• Possible inconsistencies

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Curation of event def. Coding

Analysis, Monitoring,

Management

SensorMiddleware

Sensor Network

End users

Programmers


Problem of data heterogeneity, integration

Multiple datasets, data schemas, formats, field names, conventions

The use of the observation property “Total Nitrogen”• N_TOT• Total_Nitrogen• TN

Actually want to refer to semantics, not only syntax

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Enabling users...

Enabling user-based real-time event detection

1) Sensor network system semantics (e.g. WQ sensor is located at X)

2) Domain of interest semantics (e.g. Total Nitrogen is an observable property)

3) Event semantics (e.g. Total Nitrogen at sensor#1 > 10.0 mg/L)

4) Machine-readability: for rendering in user interfaces & code generation

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SensorMiddleware

Sensor Network

End users

?





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Outline


Enable capture and consistent use of semantics

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Observation event at Flow Sensor X

Flow

PVC Pipe at George Street

100 litres per second

Flow sensor X

Flow rate sensing

Has an observation result

Some result

Has value

Produced by

implementsobserves

Has observation property

Has feature of interest

Observation event at WQ sensor

Chaffey Dam

Another result 10mg/L

WQ meter

Dissolved oxygen sensingDissolved

oxygen conc.

Observation

Feature of interest

Sensor Output Observation Value

Sensor

SensingProperty


Users creating semantic descriptions...

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Sensor Network

End users

Ontologies

SensorOntology

DomainOntology

? ? ?

EventOntology


Return notifications from triggered events with metadata based on ontology semantics

e.g. The Chaffey Dam has a problem due to <...>

Ontology-driven event detection system

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SensorMiddleware

Sensor Network

End users

Ontology-enabledUser Interface

Ontologies

SensorOntology

DomainOntology

Annotates available sensors and their capabilities

e.g. WQ sensor data at Location X

Generate code for event detection using event constraint semanticse.g. Total N > 10 mg/l

Populate user interface elements based on domain semantics and sensor network annotations.

Allow users to define event constraints

Event Ontology


Semantic Sensor

Network

Event-detection

WQdomain

WQ user

Middle ontologies

Application ontologies Domain ontologies

User ontologies

Representing domains and applications

???

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Define events using OWL 2:Event Rule, Value Constraints

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Event rule definition instances

Rule ID Observed property

Value constraint

Feature of interest

Observed By (Sensor)

1 Total N.

2 Total N. > 10 mg/l

3 Total N. > 10 mg/l Chaffey

4 Total N. > 10 mg/l WQ Sensor 1

5 Total N. > 10 mg/l Chaffey WQ Sensor 2

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Outline


Event dashboard - User interface demo

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Performing event detection over real-time sensor data using ontology-driven approaches | Jonathan Yu19 |


Ontology APIs

Ontology-driven user interface

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SensorMiddleware

(GSN)

Event dashboard

Triple store(per user definitions)

Ontology Reasoner

Ontology definitions

End usersQuery/Rule engines

Presentation Widgets(Standard web UIs

using GWT)

ESPER

SNEE

SOS

C-SPARQL/SparqlStream


DiscussionEvent descriptions using OWL2 vs. Rules (SWRL, SPIN, RIF)

• Event description approach allows adding/deleting Abox statements (instances)

• Event descriptions allow DL reasoning and SPARQL queries• Rules allow different kind of semantics to be captured• Rules require additional rules engine (triple store support?) • Can’t refer to rule statements via URIs/IRIs?

Generic UI vs. SSN coupled-UI• The latter allows for sensor/observation classes to be bound to UI• Reuse of UI given other domain ontologies (flash-flood detection)

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Future work

More complex eventsIntegrate with other event ontologies

Event-FEvent processing ODP

Incorporate processing-filters

User studies to evaluate the user interface

Deployments on actual sensor networks

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A

BEvent

Smoothing function

Ontology-enabledUser Interface

Sensor Network


Summary

Availability of real-time sensor data: many potential applications

Utilise ontologies for capture machine readable event semantics – SSN, event, domain ontologies

Event dashboard• assists user-definition of events over a given sensor network• consistent use of domain, application, sensor network semantics• UI reusable for other domains and applications

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Questions?

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Land and WaterScott GouldResearch Projects Officert +61 3 9252 6103e [email protected] www.csiro.au/clw

ICT CentreKerry TaylorPrincipal Research Scientistt +61 2 6216 7038e [email protected] www.csiro.au/ict

Land and WaterDonavan MarneyResearch team leadert +61 3 9252 6585e [email protected] www.csiro.au/clw

LAND AND WATER

Thank youLand and WaterJonathan YuResearch Software Engineert +61 3 9252 6440e [email protected] www.csiro.au/clw

Land and WaterPaul DavisResearch Scientistt +61 3 9252 6310e [email protected] www.csiro.au/clw

Land and WaterBrad ShermanResearch Scientist

e [email protected] www.csiro.au/clw

Event dashboard: Capturing user-defined semantics for event detection over real-time sensor data...

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