Mathematical analysis of various superimposed coding methods
Simon Stiassny · American Documentation · 1960
Abstract The chain‐spelling and random‐number superimposed coding methods and their variants are described. It is shown that for a given field and a given number of words to be punched therein, the above methods are equivalent as far as the probability of a match being false is concerned. For the above methods the optimum number of punches per word is 0.693 x (field size) ‐ (number of words punched) and does not depend on the vocabulary size. The staggered superimposed coding method is also described and analyzed. Charts giving the probabilities of a match being false for various vocabulary sizes, field sizes, and numbers of words punched are provided. Tables extending these figures to multi‐word inquiries are included.