Cyberman choosing to fill in gaps in the history of the Cybermen or depict new encounters between them and the Doctor. The species also appeared in the "Doctor Who" TV spin-off "Torchwood", appearing in the fourth episode, "Cyberwoman" (2006). The name "Cyberman" comes from cybernetics, a term used in Norbert Wiener's book "Cybernetics or Control and Communication in the Animal and the Machine" (MIT Press, 1948). Wiener used the term in reference to the control of complex systems in the animal world and in mechanical networks, in particular self-regulating control systems. By 1960, doctors were performing research into surgically or mechanically
Wiener–Khinchin theorem errors can show up as a divergence when the sequence length is modified. Some authors refer to formula_23 as the autocovariance function. They then proceed to normalise it, by dividing by formula_24, to obtain what they refer to as the autocorrelation function. Wiener–Khinchin theorem In applied mathematics, the Wiener–Khinchin theorem, also known as the Wiener–Khintchine theorem and sometimes as the Wiener–Khinchin–Einstein theorem or the Khinchin–Kolmogorov theorem, states that the autocorrelation function of a wide-sense-stationary random process has a spectral decomposition given by the power spectrum of that process. Norbert Wiener proved this theorem for the case of a deterministic function