Hole Detection for Increasing Coverage in Wireless Sensor Network Using   Triangular Structure
  The emerging technology of wireless sensor network (WSN) is expected to provide a broad range of applications, such as battlefield surveillance, environmental monitoring, smart spaces and so on. The coverage problem is a fundamental issue in WSN, which mainly concerns with a fundamental question: How well a sensor field is observed by the deployed sensors? Mobility is exploited to improve area coverage in a kind of hybrid sensor networks. The main objective for using mobile sensor nodes is to heal coverage holes after the initial network deployment, when designing a hole healing algorithm, the following issues need to be addressed. First, how to decide the existence of a coverage hole and how to estimate the size of a hole. Second, what are the best target locations to relocate mobile nodes to repair coverage holes? We use the triangular oriented diagram (HSTT) for aim to goal where its simple, have low calculation among construction and it is great to calculate the size of hole exactly . 
Shahram Babaie, Seyed Sajad Pirahesh
cs.NI