Time reversal of ultrasonic fields represents a way to focus through an inhomogeneous medium. This may be acomplished by a time-reversal mirror ("M) made from an array of transmit-receive transducers that respond linearly and allow the incident acoustic pressure to be sampled. The pressure field is then time-reversed and re-emitted. This process can be used to focus through inhomogeneous media ...

the present paper studies the possibility of propagation of torsional surface waves in an inhomogeneous anisotropic layer lying between two heterogeneous half-spaces (upper and lower half-space). both the half-spaces are assumed to be under compressive initial stress. the study reveals that under the assumed conditions, a torsional surface wave propagates in the medium. the dispersion relation ...

The present paper studies the possibility of propagation of torsional surface waves in an inhomogeneous anisotropic layer lying between two heterogeneous half-spaces (upper and lower half-space). Both the half-spaces are assumed to be under compressive initial stress. The study reveals that under the assumed conditions, a torsional surface wave propagates in the medium. The dispersion relation ...

P2DHMMs manage the assignment of observations to states quite well, whereas the calculation of probabilities is a great problem. To overcome some of the defects of P2DHMMs we propose the inhomogeneous P2DHMM (IP2DHMM). In contrast to some other approaches it is able to model consistently state duration and observation matrices of fixed height at no additional cost in computational load and numb...