It is very important to detect a collapse hole for coal mine workers. The possibility of detecting the collapse hole using WSN is presented, because the tunnel in coal mine is narrow and the poor working condition. Comparing three types of the hole detection methods, it is seen that the connectivity based methods are used to detect coal mine collapse better than other methods. By establishing a...

The collapse voltage of micromachined capacitive ultrasonic transducers (CMUT) depends on the size, thickness, type, and position of the metal electrode within the membrane. This paper reports the result of a finite element study of this effect. The program (ANSYS 5.7) is used to model a circular membrane on top of a Si substrate covered by a Si3N4 insulation layer. We find that the collapse vo...

In this paper we generalize existing results for the steady state distribution of growth collapse processes with independent exponential inter-collapse times to the case where they have a general distribution on the positive real line having a finite mean. In order to compute the moments of the stationary distribution, no further assumptions are needed. However, in order to compute the stationa...