Download Early Warning Systems: A Tool for Mitigation and Coordination

An Overview of
Slamet Riyadi, PhD
Early Warning Systems: A Tool for Mitigation and Coordination
Two views concerning risk: as an entity and as a
process.
CONCEPTUAL
DEFINITION OF
RISK:
Early Warning Systems: A Tool for Mitigation and Coordination
Conceptual framework
concerning risk
management.
Early Warning Systems (EWS) are
examples of measures related to
preparedness, and complement
other measures such a the
implementation of emergency
committees, emergency planning,
posting
evacuation
routes,
simulations, and exercises.
Early Warning Systems: A Tool for Mitigation and Coordination
Monitoring of precursors
to natural events.
Conceptual framework
concerning Early
Warning.
NO
Early Warning Systems (EWS) operate
on a very simple operational
framework.
Precursors to events are monitored on
a continuous basis. Data is analyzed to
generate a forecast.
Forecasting: Will
there be an event?
YES
Issue a Warning or an Alert.
If there is a forecast of a large event, a
warning is issued.
In the modern framework of EW the
emergency committees will begin
actions as proposed in the emergency
plans.
Initiate actions
according to
emergency plans
A simple process: Sound amplifier
• Input Devices = Sensors  “sense” a physical change
in some characteristic that changes in response to
some excitation, for example heat or force, and
covert that into an electrical signal.
• Output Devices = Actuators  are used to control
some external device, for example movement or
sound.
Other examples
Quantity being Input Device
Measured
(Sensor)
Light Dependant Resistor (LDR)
Photodiode
Light Level
Photo-transistor
Solar Cell
Thermocouple
Thermistor
Temperature
Thermostat
Resistive Temperature Detectors
Strain Gauge
Force/Pressure Pressure Switch
Load Cells
Potentiometer
Encoders
Position
Reflective/Slotted Opto-switch
LVDT
Output Device
(Actuator)
Lights & Lamps
LED’s & Displays
Fibre Optics
Heater
Fan
Lifts & Jacks
Electromagnet
Vibration
Motor
Solenoid
Panel Meters
Speed
Tacho-generator
Reflective/Slotted Opto-coupler
Doppler Effect Sensors
AC and DC Motors
Stepper Motor
Brake
Sound
Carbon Microphone
Piezo-electric Crystal
Bell
Buzzer
Loudspeaker
Analog Sensor
• Analogue Sensors produce a continuous output signal
or voltage which is generally proportional to the
quantity being measured.
• Physical quantities such as Temperature, Speed,
Pressure, Displacement, Strain etc are all analogue
quantities as they tend to be continuous in nature.
• For example, the temperature of a liquid can be
measured using a thermometer or thermocouple
which continuously responds to temperature changes
as the liquid is heated up or cooled down.
• Analogue sensors tend to produce output signals that
are changing smoothly and continuously over time.
• These signals tend to be very small in value from a few
mico-volts (uV) to several milli-volts (mV), so some
form of amplification is required.
• Then circuits which measure analogue signals usually
have a slow response and/or low accuracy.
• Also analogue signals can be easily converted into
digital type signals for use in micro-controller systems
by the use of analogue-to-digital converters, or ADC’s.
Digital sensor
• Digital Sensors produce a discrete digital output
signals or voltages that are a digital
representation of the quantity being measured.
• Digital sensors produce a Binary output signal in
the form of a logic “1” or a logic “0”, (“ON” or
“OFF”). This means then that a digital signal only
produces discrete (non-continuous) values.
• Compared to analogue signals, digital signals
or quantities have very high accuracies and
can be both measured and “sampled” at a
very high clock speed.
• The accuracy of the digital signal is
proportional to the number of bits used to
represent the measured quantity.
Flood EWS
Water/liquid level sensor
• Contains a series of exposed traces connected to
ground
• Before put in water: not grounded  high
resistance  no current  no signal
• After: grounded  low resistance  current flow
 signal
A seismograph or seismometer is the measuring
instrument that creates a record of the seismic
waves from an earthquake
Wave/velocity sensor
• An accelerometer is an apparatus, either
mechanical or electromechanical, for
measuring acceleration or deceleration - that
is, the rate of increase or decrease in the
velocity of a moving object.
Significant of Earthquake EWS
Even a few seconds of warning can enable protective actions
such as:
• Public: Citizens, including schoolchildren, drop, cover, and
hold on; turn off stoves, safely stop vehicles.
• Businesses: Personnel move to safe locations, automated
systems ensure elevators doors open, production lines are
shut down, sensitive equipment is placed in a safe mode.
• Medical services: Surgeons, dentists, and others stop
delicate procedures.
• Emergency responders: Open firehouse doors, personnel
prepare and prioritize response decisions.
• Power infrastructure: Protect power stations and grid
facilities from strong shaking.
Tsunami EWS
Japan earthquake and tsunami detection