  In this paper we develop a statistical mechanical interpretation of the
noiseless source coding scheme based on an absolutely optimal instantaneous
code. The notions in statistical mechanics such as statistical mechanical
entropy, temperature, and thermal equilibrium are translated into the context
of noiseless source coding. Especially, it is discovered that the temperature 1
corresponds to the average codeword length of an instantaneous code in this
statistical mechanical interpretation of noiseless source coding scheme. This
correspondence is also verified by the investigation using box-counting
dimension. Using the notion of temperature and statistical mechanical
arguments, some information-theoretic relations can be derived in the manner
which appeals to intuition.
