UNIVERSITY COLLEGE DUBLIN DUBLIN CITY UNIVERSITY TYNDALL NATIONAL INSTITUTE
Views from the coalface:chemo-sensors, sensor networks and
the semantic sensor web
Jer Hayes – CLARITY / IBM
Dublin, Ireland
UNIVERSITY COLLEGE DUBLIN DUBLIN CITY UNIVERSITY TYNDALL NATIONAL INSTITUTE
Who?• The Adaptive sensors group (ASG) is the sensor
element of the CLARITY: Centre for Sensor Web Technologies, a joint DCU-UCD research partnership funded by Science Foundation Ireland under 07/CE/I1147.
• CLARITY is a research centre that focuses on the intersection between two important research areas - Adaptive Sensing and Information Discovery.
• IBM is a CLARITY industry partner. Various Irish-based centres under the Innovative Environmental Solutions grouping.
UNIVERSITY COLLEGE DUBLIN DUBLIN CITY UNIVERSITY TYNDALL NATIONAL INSTITUTE
ASG• Novel sensing…
UNIVERSITY COLLEGE DUBLIN DUBLIN CITY UNIVERSITY TYNDALL NATIONAL INSTITUTE
About me…• I currently work for IBM
within CLARITY…
Testing wireless sensor networks at sea
Remote sensing: sea surface temp.
Food technology: spoilage sensor
UNIVERSITY COLLEGE DUBLIN DUBLIN CITY UNIVERSITY TYNDALL NATIONAL INSTITUTE
Outline
• Sensor networks
• Problems with sensors – bias?
• Core problems & an example sensor system
• Intelligence in the network
• Summary
UNIVERSITY COLLEGE DUBLIN DUBLIN CITY UNIVERSITY TYNDALL NATIONAL INSTITUTE
Sensor networks• The semantic sensor web offers the unique opportunity
to unify the real and virtual world.
• We are on the cusp of unifying real-world and virtual world…
• Large scale sensor-networks will be built around internet-enable devices (in some cases only the base-station may be internet enabled).
UNIVERSITY COLLEGE DUBLIN DUBLIN CITY UNIVERSITY TYNDALL NATIONAL INSTITUTE
Physical sensor bias• Biased towards considering sensors to be like
thermistors which is understandable as they exhibit almost ideal behaviour:– low cost, long-life, very low-power, small form factor, high
accuracy and precision, rugged, reliable, etc.
• Bias colours the expectations of SSW/WSN researchers in that they expect all sensors to conform to this ideal.
• Sensors aren’t always reliable– leaching of active components from sensing membranes,
physical damage, lack of selectivity, baseline drift and biofouling (particularly in the marine environment!).
UNIVERSITY COLLEGE DUBLIN DUBLIN CITY UNIVERSITY TYNDALL NATIONAL INSTITUTE
Dealing with raw data streams
• Given any sensor we can ask - what does this data stream mean ?
• Generally speaking data streams are not self identifying
• We require outside information, metadata, to understand the stream.
• The main driver for the use of metadata so far has been data sharing.
• Scientists generate large amounts of data and often we wish to share this data with other researchers.
UNIVERSITY COLLEGE DUBLIN DUBLIN CITY UNIVERSITY TYNDALL NATIONAL INSTITUTE
Data sharing…
SEACOOS:southeastern Atlantic coastal ocean observatory system
It involves 13 universities
and institutions
NETCDF file format
Distributed Oceanographic Data Systems (DODS)
Open Source Project for a Network Data Access Protocol (OPeNDAP)
UNIVERSITY COLLEGE DUBLIN DUBLIN CITY UNIVERSITY TYNDALL NATIONAL INSTITUTE
Core problems from our perspective
1. The heterogeneity of data sources and data transport methods that all must neatly fit into the SSW.
2. The quality of the data must be described and understood.
3. Data streams from different sources and modalities (esp. contextual information) which vary across many dimensions, including spatial, temporal, granularity of data, must be integrated.
4. The SSW must be capable of supporting analytics (e.g. decision making) across the SSW nodes.
UNIVERSITY COLLEGE DUBLIN DUBLIN CITY UNIVERSITY TYNDALL NATIONAL INSTITUTE
Phosphate system
• Component of “SmartCoast” project, which aims to develop a smart water quality monitoring system, to aid compliance with increased monitoring requirements under the Water Framework Directive.
• Phosphate is a key limiting nutrient in freshwater ecosystems.
• Eutrophication:– A major water quality problem in Ireland and many
other countries– Elevated nutrient levels lead to excessive
growth of algae and aquatic plants– Oxygen depletion fish kills– Algal blooms toxicity in water bodies
UNIVERSITY COLLEGE DUBLIN DUBLIN CITY UNIVERSITY TYNDALL NATIONAL INSTITUTE
Objective and Requirements• Develop an autonomous,
remotely controlled phosphate sensor capable of monitoring PO4
3- at appropriate levels at remote locations over long deployments
• Requirements:– Sensitive– Stable chemistry– Communicate wirelessly– Low power– Robust & portable– Low cost & low maintenance
requirements
UNIVERSITY COLLEGE DUBLIN DUBLIN CITY UNIVERSITY TYNDALL NATIONAL INSTITUTE
Principle of Operation
• Yellow method for phosphate detection– Forms vanadomolybdophosphoric
acid (yellow)– Absorption proportional to phosphate
conc.– Advantages
• Excellent reagent stability• Fast reaction time (minutes)
• Microfluidic technology– Minimizes reagent consumption,
storage requirements and pumping power
• UV-LED and photodiode– Low powered, inexpensive &
sensitive optical detection
UNIVERSITY COLLEGE DUBLIN DUBLIN CITY UNIVERSITY TYNDALL NATIONAL INSTITUTE
Current Status• Mark II sensor designed to
build on the successes and address the limitations of the original.
• Improvements– Lower power, more flexible fluid
handling system.– More sensitive optical detection
system.– More reliable and lower powered
communications using GSM modem in SMS mode.
– 2 point calibration protocol.– Solar panel for energy harvesting
during long deployments.– Improved ruggedisation.
Yeah, so what? What about the semantic sensor web?!!!
UNIVERSITY COLLEGE DUBLIN DUBLIN CITY UNIVERSITY TYNDALL NATIONAL INSTITUTE
Problems at the coalface…
1. How do we plug this sensor into a sensor network and / or the semantic sensor web?
• What? Where? When? Who?
2. What is “context” for this sensor? How do we find it and can we trust it?
• Weather? Other water quality parameters.• Data from models? Topology, soil type, land use in river basin
district…• For other sensors what “context” is could be complex.
3. Can the network control the device properly? Can it change sampling rates etc.?
• Do we just pass on data or can we control the device? Who is allowed to control it?
UNIVERSITY COLLEGE DUBLIN DUBLIN CITY UNIVERSITY TYNDALL NATIONAL INSTITUTE
Problems at the coalface…
1. We are looking for a “complete picture” – so data streams will come from hardware & software, e.g. modelling.
• Air quality…• Ground based in-situ
sensors
• Remote sensing
• Models: chemical transport, weather etc.
Software sensors (Models/Database & Hardware sensors?
UNIVERSITY COLLEGE DUBLIN DUBLIN CITY UNIVERSITY TYNDALL NATIONAL INSTITUTE
CH4
CO2
VOCs
Landfill gas generation
Borehole well
Gas sample extracted
Analysed using IR gas sensor
Chemometric program analyses data and decides if concentrations are within threshold limits
If thresholds are exceeded, a message to sent to personnel onsite to investigate further
UNIVERSITY COLLEGE DUBLIN DUBLIN CITY UNIVERSITY TYNDALL NATIONAL INSTITUTE
Intelligence?
• OGC's Sensor Web Enablement (SWE):
Where should the analytics take place?
How do we know contextual information is accurate?
Should “bad data” be released?
Where does the landfill site fit in?
UNIVERSITY COLLEGE DUBLIN DUBLIN CITY UNIVERSITY TYNDALL NATIONAL INSTITUTE
Summary…
1. Sensors aren’t as reliable as we’d like to think.• Need to account for data quality….
2. Contextual information is required for the “complete picture”.• From a large variety of possible sources…
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