Sensor Networks - II in IoT

Node Behavior in WSNs

Normal nodes work perfectly in ideal environment condition
Failed nodes are simply those that are unable to perform an operation; this could be because of power failure and environment events.
Badly failed nodes exhibit features of failed nodes but they can also send false routing messages which are a threat to the integrity of the network.
Selfish nodes are typified by their unwillingness to cooperate as the protocol requires whenever there is a personal cost involved. Packet dropping is the main attack by selfish nodes.
Malicious nodes aim to deliberately disrupt the correct operation of the routing protocol, denying network service if possible.

Dynamic Misbehavior : Dump Behavior

Detection of such temporary misbehavior in order to preserve normal functioning of the network - coinage and discovery of dump behavior
In the presence of adverse environment condition (high temperature, rainfall, and fog) the communication range shrinks
A sensor node can sense its surrounding but is unable to transmit the sensed data.
With the resumption of favorable environment conditions, dump nodes work normally
Dump behavior is temporal in nature (as it is dependent on the effects of environment conditions)

Detection and Connectivity Re-establishment

The presence of dump nodes impedes the overall network performance
Detection, and , subsequently, the re-establishment of network connectivity is crucial
The sensed information can only be utilized if the connectivity between each dumb node other nodes in the network could be re-established
Before restoration of network connectivity , it is essential to detect the dumb nodes in the network.
CoRD and CoRAD are two popular schemes that re-establish the connectivity between dumb nodes with others.

Event-Aware Topology Management in Wireless Sensor Network

Timely detection of an event of interest
Monitoring the event
Disseminating event-data to the sink
Adapting with the changes of event state

         - Event location
         - Event area
         - Event duration

Information Theoretic Self-Management of Wireless Sensor Networks

A WSN is deployed with the intention of acquiring information
The sensed information are transmitted in the form of packets
Information theoretic self - management (INTSEM) controls the transmission rate of a node by adjusting a node's sleep time
Benefits

- Reduce consumption of transmission energy of transmitters
- Reduce consumption of receiving energy of relay nodes

General Framework of InTSeM

Social Sensing in WSNs

Social Sensing -based Duty Cycle Management for Monitoring rare Events in Wireless Sensor Networks

WSN are energy-constrained
Scenario:

         - Event monitoring using WSNs
         - WSN suffer from ineffective sensing for rare events
         - Event monitoring or sensing, even if there is no event to monitor or sense
        - EXAMPLE : SUBMARINE MONITORING IN UNDERWATER SURVEILLANCE