Prithvi Security Wireless Sensor Networks(WSNs) Specialists

3. Wireless Sensor Networks
• A collection of sensing devices that can
communicate wirelessly
• Each device can sense, process, and
talk to its peers
• Typically, centralized collection point
(sink or base station)

4. Sensor Node deployment and Communication Infrastructure
Internet and
Satellite
Task Manager
node
Sink A
B
C
D
E
Sensor Field
Sensor Node
User

5. Sensor Node
A sensing node has 3 basic components:
CPU
 radio transceiver
sensor array

6. Sensor Node Architecture

7. Sensors
A sensor is a small hardware device
which is capable of generating response
to change in physical environment.
Although sensors are of different type
which are application specific but
desired characteristics of a sensor node
are small size and low power
consumption

8. Energy conservation
• Goal: unsupervised operation with
no maintenance
• Nodes need to conserve energy
• Radio is power-hungry!

9. A WSN typically has little or no
infrastructure. It consists of a
number of sensor nodes (few tens
to thousands) working together to
monitor a region to obtain data
about the environment.

10. Gateway
Server
Internet
Communication’s
barrier
Sensor field
Soil Moisture etc.
Mote

11. Applications
WSN applications can be classified into two
categories:
•Monitoring
•Tracking

12. Monitoring applications
•indoor/outdoor environmental monitoring viz., agriculture,
air / water pollution
•health and wellness monitoring, power monitoring, inventory
•location monitoring, factory and process automation viz.,
pipeline
•seismic and structural monitoring.

13. Tracking objects
•animals
•humans
•vehicles.

14. Health Applications
Sensor networks are also widely used in
health care area. In some modern hospital
sensor networks are constructed to monitor
patient physiological data, to control the drug
administration track and monitor patients and
doctors and inside a hospital. They support
fall detection, unconsciousness detection,
vital sign monitoring and dietary/exercise
monitoring.

16. WSNs are also used to form BAN(Body Area
Network) which is placed close to body of
patient and is used to monitor patient’s heart
beat rate and breath rate and movements.

18. Military Applications
Sensor networks can provide variety of
services to military and air force like
information collection, battlefield surveillance,
intrusion detection and attack detection. In
this field of application sensor networks have
quite an advantage over other networks
because enemy attacks can damage or
destroy some of the nodes but nodes failure
in WSN doesn’t affect the whole network.

20. Intrusion detection
Sensor network can be used as a 2-phase in
Intrusion Detection System. Instead of using
mines intrusion can be detected by
establishing sensor network in that area.
Mines are dangerous to civilians so instead
sensor nodes sense the detection and alarm
the army. The response to prevent intrusion is
now decided by the military.

21. Enemy Tracking and target classification
Objects moving with significant metallic
content can be detected using specially
designed sensors. So enemies can be tracked
and civilians are ignored. This system
specially helps in detecting armed soldiers
and vehicles.

22. Battlefield surveillance
Critical areas and borders can be
closely monitored using sensor
networks to obtain information
about any enemy activity in that
area. This provides quick gathering
of information provides time for
quick response.

23. Battlefield damage assessment
Sensor networks can be deployed
after the battle or attacks to gather
information of damage assessment.

24. Detection of NBC attacks
Sensor networks can be used as Nuclear,
Biological and Chemical warning system. If
any nuclear biological or chemical agents can
be detected by sensors and embedded alert
system can now send a warning message. It
provides the military critical response time to
check the situation and prevent possible
attacks which can save lives of many.

25. Targeting system
Sensors can be embedded in weapons.
Exact information about the target like
distance, angle can be collected and
sent to the shooter. So sensors can be
collaborated with the weapons for better
target assessment.

26. Agricultural Monitoring
WSN in agriculture helps in distributed
data collection, monitoring in harsh
environments, precise irrigation and
fertilizer supply to produce profuse crop
production while diminishing cost and
assisting farmers in real time data
gathering.

28. The proposed agricultural environment
monitoring server system collects
environmental and soil information on the
outdoors through WSN-based environmental
and soil sensors.

29. Applications
WSNs can be used for studying the local environment which is helpful in
agriculture. Sensors are used to monitor the
following conditions:
Temperature
Humidity
Soil moisture
Wind speed and direction
Rainfall
Sunshine
Level of CO2

30. Precision Agriculture
Precision agriculture is a method of farm management that
enables farmers to produce more efficiently through a frugal use
of resources.
Motivation:
•traditionally, a large farm is taken as homogeneous field in
terms of resource distribution and its response to climate
change, weeds, and pests
•accordingly, farmers administer
•fertilizers, pesticides, herbicides, and water resources
•in reality, wide spatial diversity in soil types, nutrient content,
and other important factors

31. Requirements of precision agriculture technologies
•collect a large amount of data
•over several days
•monitoring the humidity and temperature
conditions in the field
•monitoring the wetness
•determining the potential risk of the disease and
the need for fungicides

32. Environmental
Applications
Another major area of application of WSN is
environmental monitoring. WSNs are
deployed for habitat monitoring,
flood detections , forest fire detection etc.

34. Forest Fire detection
Millions of sensor nodes can be
deployed which use distributed sensing
and collaborate with each other to
provide information. So fire can be
detected and exact location of fire origin
can be provided before the fire is
uncontrollable

35. Flood detection
ALERT systems use sensors for
rain, water level and weather.
Information collected by these
sensors can forecast the possible
flood threats thus providing help for
disaster management.

36. Pollution Monitoring
WSNs can be deployed for monitoring the
level of pollution and warning generation.
Air Pollution Monitoring Systems are
deployed in cities like London and Brisbane
to monitor the level of pollutants.
These sensor networks look for amount of
poisonous gases and these statistics are
studied to analyze if pollution has increased
and take actions to check pollution

38. Disaster Management
Applications
WSNs can also be used for other disaster
management like earthquake and landslide
monitoring and disaster assessment.

40. Disaster monitoring
Motivation
•most of Earth’s changes of
climate are hidden from view
•at present, typical changes are
monitored using expensive
devices that are difficult to move

41. •the deployment and maintenance
of these devices require expensive
assistance
•data storage must be retrieved on
a periodic basis

42. WSNs can be very useful for weather /
climate monitoring
•a large number of small, cheap,
and self-organizing nodes
•can be deployed to cover a vast
field

43. Advantage of WSNs in active disaster
monitoring
•fast and economical deployment
•possible to achieve high spatial
diversity
•the networks can operate without
requiring stringent maintenance
routines

44. An important task in active disaster
monitoring is to capture discrete events
•eruptions, earthquakes, or tremor
activities
•these events are transient
•occurring several times a day

45. Therefore, the researchers used the raw
data to investigate volcanic activities
the samples must be accurately time
stamped to allow comparisons
between correlated measurements

46. Conclusion
•WSNs are suitable for capturing
triggered events
•WSNs are inadequate for
capturing complete waveforms for
a long period of time

47. Pipeline Monitoring
Monitoring gas, water and oil
pipelines
Motivation:
•management of pipelines
presents a formidable challenge

48. •long length, high value, high
risk
•difficult access conditions
•requires continuous and
unobtrusive monitoring

50. Pipeline leakages can occur due to
excessive deformations
•Earthquakes
•landslides or collisions with an
external force

51. •corrosion, wear, material flaws
•intentional damage to the
structure

52. To detect leakages, it is vital to
understand the characteristics of the
substance the pipelines transport
•fluid pipelines generate a hot-spot
at the location of the leak
•gas pipelines generate a cold-spot
due to the gas pressure relaxation

53. •fluid travels at a higher
propagation velocity in metal
pipelines than in a Polyvinyl
Chloride (PVC)
•a large number of commercially
available sensors to detect and
localize thermal anomalies

54. •fiber optics sensors
•temperature sensors
•acoustic sensors

55. The PipeNet prototype
The task is to monitor
•hydraulic and water quality by measuring
pressure and pH
•the water level in combined sewer system
•sewer collectors and combined sewer
outflows

56. Industrial Sensing
Managing inventory control
Each item in a warehouse may have a sensor
node attached to it. The end users can
find out the exact location of the item with the
help of sensor and tally the number of items
in the same category stored in
the database.

57. Structural Health
Monitoring
Motivation
events:
•on August 2, 2007, a highway bridge unexpectedly
collapsed in Minnesota
•nine people were killed in the event
•potential causes: wear and tear, weather, and the
weight of a nearby construction project
•in fact, the BBC reported (August 14, 2007) that China
had identified more than 6,000 bridges that were
damaged or considered to be dangerous

58. these accidents motivate wireless
sensor networks for monitoring
bridges and similar structures

59. Motivation
traditional inspections
•visual inspection  everyday
•labor-intensive, tedious, inconsistent, and
subjective
•basic inspections  at least once a year
•detailed inspection  at least every five years
on selected bridges
•special inspections  according to technical
needs
•the rest require sophisticated tools 
expensive, bulky, and power consuming

60. Underground Mining
Motivation:
one of the most dangerous work
environments in the world incident
of August 3, 2007 at the Crandall
Canyon mine, Utah, USA

61. •six miners were trapped inside
the coal mine
•their precise location was not
known

62. •the owners of the mine claimed
a natural earthquake was the
cause while scientists suspect
the mine operations caused
seismic spikes
•a costly and irksome rescue
attempt went underway

63. Advantages of WSNs over traditional methods
Wide coverage
Long monitoring periods
No individual tracking
Data available directly to researcher’s
location
Land and Aquatic Coverage
Continuous monitoring

64. WSN Operating
Systems
•TinyOS
•Contiki
•MANTIS
•Btnut
•SOS
•Nano-RK

65. TinyOS:
•Event-driven programming model
instead of multithreading
•TinyOS and its programs written in
nesC

66. TinyOS Charactersitics:
•Small memory footprint
non-preemptable FIFO task
scheduling
•Power Efficient
Puts microcontroller to sleep
Puts radio to sleep

67. •Concurrency-Intensive Operations
Event-driven architecture
Efficient Interrupts and event
handling
•No Real-time guarantees

68. WSN Simulators
•NS-2
•GloMoSim
•OPNET
•SensorSim

69. •J-Sim
•OMNeT++
•Sidh
•SENS

70. WSN Emulators
•TOSSIM
•ATEMU
•Avrora
•EmStar