A wireless sensor network (WSN) consists of distributed sensors to monitor environmental conditions such as temperature, sound, vibration, pressure, motion or detect dimensions, to pass their data through the network to a base station for processing. Advantages of WSN over a wired system considered in elimination of wiring cost, sensors can be installed in harsh environments. Each sensor node is a combination of Radio transceiver with an internal antenna or connection to an external antenna micro-controller, electronic circuit for interfacing with the sensors, energy source, usually a battery or an embedded form of energy harvesting. Drawback of using sensors is having limited power to consume, a memory that is capable of performing limited computations, in addition to probability of communication failures between nodes.
Sensor-based networks basically are characterized by their continuous mode of operation and power sources, which increases the fault rates in sensors, knowing that maintenance or replacement of sensors is considered expensive.
Fault tolerant techniques are based on time redundancy or space redundancy or combination of both. As mentioned previously, a sensor has a limited computation power, so time redundancy techniques are not supposed to be of beneficial. Traditional techniques in backing up sensors are based on double and triple redundancy, which doesn’t satisfy the requirement of having a reliable network with a minimum number of sensors.
This work aims to design an algorithm that finds the minimum number of detection sensors needed in a network for a certain application. Plus, obtaining the minimum number of sensors needed to back up the core sensors.
• Pattern to be detected are defined and fed to the algorithm prior to execution
• The application is susceptible to a single failure at a time
Sensor Resource Assignment and allocation
In this section, we formulate the sensor resource allocation (SRA) problem and establish the complexity of the proposed problem.
The SENSOR RESOURCE ASSIGNMENT (SRA) PROBLEM can be formulated in the following way.
Problem: Set A of points pi (xi1,xi2,xi3), in 3- dimensional space where 1<= i <= 6, the three parameters are represented by dimension, weight and color. J is a set that consists of all possible 2-Dimensional hyper planes that are perpendicular to one of the 3 axes, such that each hyper plane is separating two item patterns pi and pj that have the closest coordinates along the axis to which the hyper plane is perpendicular, j doesn’t equal i and 1<= j<= 6. Hyper planes in our case are the locations where we need to place sensors of multiple types to distinguish all the points which are the 6 pattern of items.
Our aim is to find a subset of selected hyper planes H with minimal and optimal cost, such that any two points pi and pj, are separated by at least one of the selected hyperplanes and also the cardinality of...