Theory of non-equilibrium transport has progressed a lot. The self-consistent theory of both electric and phonon (and hence heat) currents including the electro-phonon coupling effects between them has been developed and it provides us useful information of the heat generation and the heat dissipation effects accompanying the currents. It will be a useful basic theory for the device simulator, if it could be combined with a large scale electronic structure method something like the DFTB method with which micron meter scale devices can be handled within realistic computational resources. The progress in this direction would be very fruitful for both semiconductor physics and device physics. Yet another useful example is a more material oriented study. In terms of the standard first principle Non-Equilibrium Green Function (NEGF) method, for an example, we discuss channel and electrode material dependence in electric current versus bias voltage profile of the resistive random access memory cell.