Wireless intelligent sensor networks (WISNs)
monitor the natural environment,3 using fields of
sensors to take periodic readings and report results,
together with derived values, to a central repository.
In a dedicated WISN, sensors are arranged over a
specific area. However, tracing human activity is
difficult using a traditional WISN because human
activities and locations are rarely known prior to
an event. With mobile network technologies, which
integrate a variety of sensors into smartphones, it’s
easier to monitor people’s activities and help them
escape disasters. In addition, the powerful processing
and connecting capability of smartphones can
be used to give people evacuation instructions.
Because of the number of active sensors in a
disaster environment, the data processing and analyzing
module should be scalable, providing enough
peak capability for the disaster context. A datacenter’s
reconfigurable architecture supports this scalability
using infrastructure as a service (IaaS).4,5
Most current datacenters use a tree architecture, in
which computing power adjusts as demand changes.
The software deployed on a datacenter also supports
scalability. For example, MapReduce delivers a large
amount of data to many running nodes, with each
running node processing only one part of the data 6
Our smart cloud evacuation system (SCES) uses
smartphones and datacenters to provide scalable
performance for energy saving at the front end and
adjustable performance at the back end. The SCES
is a sensor-portable monitoring and emergency decision
system that supports fast disaster response. It
provides a user-friendly supporting architecture for
collecting and analyzing real-time information on-site
so individual escape guidance is delivered to public.
Case Study: Levee Erosion
When Hurricane Katrina hit the New Orleans region
in 2005, levee failures on the canals allowed
water to pour into St. Bernard Parish and New Orleans
East. The continuing effects of saltwater intrusion
driven by Katrina can still be seen in the
wilting trees and plants far from the coast. The inland
saltwater intrusion caused the state’s rice crop
to decrease by 20 percent that year, with some fields
taking as much as two years to recover.7
Lake Pontchartrain is one of the few examples
of quick ecological recovery following the record
storm season. In the weeks after Katrina, polluted
floodwater, dubbed a “toxic stew,” was pumped directly
from the streets of New Orleans into the lake.
The Lake Pontchartrain Basin Foundation, which
estimated that about 10 billion gallons of contaminated
water were dumped into Pontchartrain, started
to monitor the bacteria counts per drop almost
immediately after the pumping stopped in October.7
Fortunately, the total contaminated water was less
than 10 percent of the lake’s volume, so the ecological
system was able to recover quickly.
To address levee failure, we put various sensors
behind the wall of levees in Lake Pontchartrain to
monitor structural erosion. Some sensors will detect
the levee erosion level and periodically report to the
back-end datacenter. Additional data transferred includes
water level, temperature, and bacteria count.
If the lake’s water level is too high and there’s a possibility
of flooding, the datacenter will automatically