Recent DNS studies of buoyant bubbly flows in vertical channels are discussed. Simulations of nearly spherical bubbly flows in vertical channels show that the bubbles move towards the wall for upflow and away from the wall for downflow in such a way that the core is in hydrostatic equilibrium. For downflow the wall layer is free of bubbles but for upflow there is an excess of bubbles in the wal...

Channel identiication for a binary phase-shift keyed (BPSK) direct-sequence spread-spectrum (DS/SS) system operating over a fading channel with sampling at the chip rate is considered in this work. The system is mapped to a discrete oversampled system, thereby allowing channel identiication via second order statistics under a few nonrestrictive conditions. Using the method of subchannel respons...

The present paper analyzes adjacent channel interference in TETRA Direct Mode Operation (DMO) for indoor and outdoor environments. To determine minimal stay-away distance and interference area propagation model is used. Thus, a brief overview of free space, Bacon and CEPT SE21 propagation models, mentioned in the TETRA DMO standard is given and two-ray and multi-wall models are described and ev...

It has been shown that an extension of the basic binary polar transformation also polarizes over finite fields. With it the direct encoding of q-ary sources and channels is a process that can be implemented with simple and efficient algorithms. However, direct polar decoding of q-ary sources and channels is more involved. In this paper we obtain a recursive equation for the likelihood ratio exp...