ABSTRACT
We discussed in detail the entropy theory of information in Chap. 4. The relationship between physical entropy and information theory was derived strictly from the statistical thermodynamic approach. We showed that information and entropy can be traded. However, information is gained inevitably at the expense of increasing entropy from a diiferent source. This relationship of entropy and information was first recognized by Szilard [1, 2] in 1929 and later successfully applied by Brillouin [3, 4] in 1951. In practice, the amount of increasing entropy from a diiferent source is generally excessive. In principle, the amount of information gain at best can only approach the equivalent amount of entropy traded off:
In this chapter we discuss one of the most interesting applications of the entropy theory of information, namely, the demon's operation and information theory.
