Surname 3
and resolving such instances as unexpected changes in output quality, abnormal vibration,
noise or other pointers of potentially undesirable issues (Jain et al. 1218). Technicians may
attach the needed sensor nodes to relevant points in the equipment process line, and the sensor
nodes will form a link by themselves. This kind of practice is necessary, especially when
measuring speed, vibration, temperature or pressure in a particular point in the machine or in
the entire machine. The nodes, which are equipped with smart I/O system to determine the
sensor types, identify the information to be evaluated and transmit it to a hand-held base station
device wirelessly (Jain et al. 1219; Polk and Sean 148). These overlay systems may be timely
integrated and quickly eliminated once issues are determined and resolved.
SECURE LOCALIZATION
The majority of WSNs possess a large amount of sensor nodes which may be distributed
randomly over the application point. The technique may be for instance a random scattering
from an aircraft. It may be inferred from this argument that WSN protocols may not know
initially which particular nodes will be within communication proximity of each other after
placement (Rouhiainen 15). Additionally, the fact that there is inadequate predetermined
network infrastructure creates a need for the WSNs to establish links and maintain network
connectivity independently. The issue of establishing the geographical location of the node and
its relative position within the WSN is called localization (Rouhiainen 15).
Current direct localization techniques include GPS or manual location pre-
configuration. Integrating GPS receiver into nodes may be considered to be a simple solution
to the issue (Rouhiainen 15). Nonetheless, a GPS-based system is not applicable for indoor
WSN applications, and it has also been found to be quite unreliable when sensors are placed in
surroundings with obstructions, say dense foliage regions. Moreover, despite the fact that GPS
receivers are considerably small in terms of size, there application leads to a substantial battery
drain and raise the expenses incurred for controlled sensor nodes. The pre-configuration of
node positions done, if manually, may also be considered to be a probable solution (Rouhiainen
15). However, it also has its setbacks. It creates substantial hindrances to WSN applications.
The node positions have to be entirely static, and random placement techniques cannot be
employed. Such issues make manual configuration technique very costly with regard to time
consumption. Moreover, this technique scales very poorly, making it inapplicable for large
scale WSNs. The restrictions of sensor nodes and the inappropriateness of manual
configuration has caused many researchers in this field to seek for substitute secure localization
solutions (Miorandi et al. 1502).
Solutions. The indirect localization techniques are built around placing nodes relative to other
nodes which are located at a proximate position. They were developed to resolve the issues of
direct localization techniques, at the same time maintaining the precision of location. A
majority of the indirect localization techniques are built around the application of beacon
nodes. Beacon nodes tend to be aware of their own position and, therefore, assist sensor nodes
in establishing their location (Kozlov et al. 213). They are also few in terms of number as
compared to sensor nodes and are therefore able to use GPS receiver. Furthermore, because of
these properties they can be their position may be configured manually. Nonetheless, this
technique also has its security issues (Kozlov et al. 213). Since the beacon nodes, like the sensor
nodes, are deployed in hostile environments, they are susceptible to physical node capture or
other attacks. The chances of beacon nodes offering false data have to be considered too.
