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That paper includes an example of frequency aliasing dating back to 1922. The first published use of the term "aliasing" in this context is due to Blackman and Tukey in 1958. [ 5 ] In their preface to the Dover reprint [ 6 ] of this paper, they point out that the idea of aliasing had been illustrated graphically by Stumpf [ 7 ] ten years prior.
In negative frequency-dependent selection, the fitness of a phenotype or genotype decreases as it becomes more common. This is an example of balancing selection. More generally, frequency-dependent selection includes when biological interactions make an individual's fitness depend on the frequencies of other phenotypes or genotypes in the ...
Effects of aliasing, blurring, and sharpening may be adjusted with digital filtering implemented in software, which necessarily follows the theoretical principles. A family of sinusoids at the critical frequency, all having the same sample sequences of alternating +1 and –1.
For example, a factory that is lit from a single-phase supply with basic lighting will have a flicker of 100 or 120 Hz (depending on country, 50 Hz x 2 in Europe, 60 Hz x 2 in US, double the nominal frequency), thus any machinery rotating at multiples of 50 or 60 Hz (3000–3600rpm) may appear to not be turning, increasing the risk of injury to ...
Aliasing is an automatic and unavoidable result of observing such a fraction. [3] [4] The aliasing properties of a design are often summarized by giving its resolution. This measures the degree to which the design avoids aliasing between main effects and important interactions. [5]
In positive frequency-dependent selection the fitness of a phenotype increases as it becomes more common. In negative frequency-dependent selection the fitness of a phenotype decreases as it becomes more common. For example, in prey switching, rare morphs of prey are actually fitter due to predators concentrating on the more frequent morphs. As ...
English: Graph of frequency aliasing, showing folding frequency and periodicity. Frequencies above ƒ s /2 (the Nyquist frequency) have an alias below ƒ s /2, whose value is given by this graph. See Spectral imaging of the atmosphere, by G. G. Shepherd, Figure 2.9(a), p. 43 for similar diagram.
In structural biology, as well as in virtually all sciences that produce three-dimensional data, the Fourier shell correlation (FSC) measures the normalised cross-correlation coefficient between two 3-dimensional volumes over corresponding shells in Fourier space (i.e., as a function of spatial frequency [1]).