Introduction - Energy Harvesting Autonomous Sensor Systems - page 4

ambient objects, environments are able to recognize and respond to the pres-
ence and behaviour of any individual in a personalized and relevant way.
With the recent advances in wireless communication technologies, sensors
and actuators, and highly integrated microelectronics technologies, WSNs
have gained worldwide attention to facilitate monitoring and controlling of
physical environments from remote locations that could be difficult or danger-
ous to reach. In the Massachusetts Institute of Technology (MIT) Technology
Review magazine of innovation published in February 2003 [3], the editors
identified WSNs as the first of the top 10 emerging technologies that will
change the world.
Across many industries, products and practices are being transformed by
these networked communicating sensors and computing intelligence. The
smart industrial gear includes jet engines, bridges, and oil rigs that alert their
human minders when they need repairs, before equipment failures occur.
Computers track sensor data on operating performance of a jet engine or
slight structural changes in an oil rig, looking for telltale patterns that signal
coming trouble. Sensors on fruit and vegetable cartons can track location
and sniff the produce, warning in advance of spoilage so shipments can be
rerouted or rescheduled. Computers pull GPS data from railway locomotives,
taking into account the weight and length of trains, the terrain, and turns to
reduce unnecessary braking and curb fuel consumption by up to 10%.

1.1.1 Architecture of WSNs

WSNs represent a significant improvement over wired sensor networks with
the elimination of the hardwired communication cables and associated in-
stallation and maintenance costs. An overview of these network systems
is illustrated in Figure 1.4 . The architecture of a WSN typically consists of

Point-to-Point
Wireless Networks

Wireless Mesh
Networks

Wire d Networks

Standard reliable
wired network
High installation cost
High maintenance cost
Inflexible network

Less reliable than wired
network
Low installation cost
High maintenance cost
Flexible network but
limited reach (coverage)

High reliability wireless
network
Low installation cost
Low maintenance cost
Flexible network with
long reach (coverage)

FIGURE 1.4
Comparison of WSN and IOT.