Image Processing Reference
In-Depth Information
A first classification of wireless sensor networks can be made based on the complexity of the
networks involved []:
•
“
Intelligent
”
warehouse
—Eachitemtobemonitoredinsideawarehouseis“tagged”witha
small device; these tags are monitored by the fixed sensor nodes embedded into the walls
andshelves.Basedonthereaddata,knowledgeofthespatialpositioningofthesensors
and time information, the sensor network offers information about the traffic of goods
inside the building, creates automatic inventories, and even performs long-term correla-
tions between the read data. The need of manual product scanning thus disappears. In
this category, we can include the scenario of the modern supermarket, where the selected
products of the customers are automatically identified at the exit of the supermarket.
From the point of view of complexity, this scenario requires a minimum of complexity.
The infrastructure sensor nodes are placed at fixed positions, in a more or less random
manner. The deployment area is easily accessible and some infrastructures (e.g., power
supplies and computers) already exist. At the same time, the nodes are operating in a
“safe” controlled environment meaning that there are no major external factors that can
influence or destroy them.
•
Environmental monitoring
—hisisthewidestareaofapplicationsenvisionedupto
now. A particular application in this category is disaster monitoring. The sensor nodes
deployed in the affected areas can help humans estimate the effects of the disaster,
build maps of the safe areas, and direct the human actions toward the affected regions.
A large number of applications in this category address monitoring of the wildlife. his
scenario has an increased complexity. The area of deployment is no longer accessi-
ble in an easy manner and no longer safe for the sensor nodes. There is hardly any
infrastructure present, nodes have to be scattered around in a random manner and
the network might contain moving nodes. Also a larger number of nodes need to be
deployed.
•
Very large scale sensor networks applications
—hescenarioofalargecitywhereallthe
cars have integrated sensors. These sensor nodes communicate with each other collect-
ing information about the traffic, routes, and special traffic conditions. On one hand,
new information is available to the driver of each car. On the other hand, a global view
of the whole picture can also be available. The two main constraints that characterize
this scenario are the large number of nodes and their high mobility. The algorithms
employed need to scale well and deal with a network with a continuously changing
topology.
On the other hand, the authors of Ref. [] present a classification of sensor networks based on
their area of application. It takes into consideration only the military, environment, health, home, and
other commercial areas, and can be extended with additional categories such as space exploration,
chemical processing, and disaster relief.
•
Military applications
—Factors as rapid deployment, self-organization, and increased fault
tolerance make wireless sensor networks a very good candidate for usage in the mili-
taryield.heyaresuitedtodeploymentinbattleieldscenariosduetothelargesizeof
the network and the automatic self-reconfiguration at the moment of the destruction or
unavailability of some sensor nodes []. Typical applications are monitoring of friendly
forces, equipment, and ammunition; battlefield surveillance; reconnaissance of oppos-
ing forces and terrain, targeting, battle damage assessment; and nuclear, biological, and
chemical attack detection and reconnaissance. A large number of projects have already
been sponsored by he Defense Advanced Research Projects Agency.
