A speech classification technique for robust classification of varying modes of speech to enable maximum performance of multi-mode variable bit rate encoding techniques. The press roller includes an elastic layer and at least one heating element contained in the elastic layer to allow generation of heat from the interior of the elastic layer. The average thickness of the first soft magnetic layer is formed in the range of 5 to 60 \u212b. In addition, for each resource the descriptor can also specify one or more relationships with other resources.