Research
a New Three Dimensional Clustering Method for Wireless Sensor Networks
Today, the wireless sensor networks are popular therefore they have high features such as small tools, high computational ability and usability in all environments. But restriction power is the weakness that clustering is trying to improve. Clustering usually pays attention to two imensional WSNs. In this paper, three-dimensional geometric forms have been focused for some places in which reviewing different environments with different surfaces is necessary. Based on a mathematical model for the presented 3D clustering method we calculate the network life time according to the number of used sensors.
Redundancy Effect on Fault Tolerance in Wireless Sensor Networks
There are several usages for wireless sensor networks in military, supervisory, region considering, physiology, etc. Sensor nodes are usually equipped with some non chargeable batteries having limitations in lifetime while they cannot be replaced with other sensors when they fail. Each sensor has a failure probability which is affected from some factors like electrical energy, hardware failures, communication error, undesired environment situations, etc. Thus, fault tolerant is a very important and critical factor in such networks. Hardware redundancies like having redundant nodes and paths are suitable echniques used for increasing fault tolerant factor. On the other hand, using hardware redundancies leads increasing in overall network consumption because of using more number of sensors. In this paper we estimate the affect of redundancy on the number of correct responses that wireless sensor networks have on the received queries and also show the level of redundancy needed in different network conditions like having different fault probabilities and needed clusters to response the received queries. Keywords: wireless sensor network, fault tolerance, redundancy, reliability
