Heartbeat intervals during atrial fibrillation are commonly believed to form a series of almost independent variables. The series extracted from 24h Holter recordings show a nonstationary behavior. Because of nonstationarity it is difficult to give a quantitative measure of independence. In this...

Hao proposed a graphic representation of subsequence structure in DNA sequences and computed fractal dimensions of such representations for factorizable languages. In this study, we extend Hao's work in several directions: (1) We generalize Hao's scheme to accommodate sequences over an arbitrary...

A dynamical-systems-based model of computation is studied. We demonstrate the computational ability of nonlinear mappings. There exists a switching map system with two types of baker's map to emulate any Turing machine. Taking non-hyperbolic mappings with second-order nonlinearity (e.g., the...

We examine the one-humped map at the period-doubling transition to chaos, and ask whether its long-term memory is stack-like (last-in, first-out) or queue-like (first-in, first-out). We show that it can be recognized by a real-time automaton with one queue, or two stacks, and give several new...