I. Introduction
The metric of complexity proposed by Lempel and Ziv (LZ) to evaluate the randomness of finite sequences has been extensively used to solve information theoretic problems [1]–[9] and applications such as coding [10]–[12], data compression [13]–[19], and generation of test signals [20]–[22]. This complexity measure is related to the number of distinct substrings (i.e., patterns) and the rate of their occurrence along a given sequence [2].