The Document Object Model of a sampled web page is used to create a rule that extracts item-related data from web pages having a similar DOM structure to the sampled web page. This ensures that air is present in the cylinder in a space where fuel will be admitted and combustion will occur. From the characteristic curve of a plane formed by mask channel width and source-drain conductance, there is extracted a virtual point at which the change of source-drain conductance is estimated to be approximately zero even if the gate overdrive is finely changed. Thus audio being reproduced by said audio player apparatus is adapted to the current audio taste andor mood of users present at the location of the audio player apparatus.