  Sensor networks aim at monitoring their surroundings for event detection and
object tracking. But due to failure or death of sensors, false signal can be
transmitted. In this paper, we consider the problem of fault detection in
wireless sensor network (WSN), in particular, addressing both the noise-related
measurement error and sensor fault simultaneously in fault detection. We assume
that the sensors are placed at the center of a square (or hexagonal) cell in
region of interest (ROI) and, if the event occurs, it occurs at a particular
cell of the ROI. We propose fault detection schemes that take into account
error probabilities into the optimal event detection process. We develop the
schemes under the consideration of Neyman-Pearson test and Bayes test.
