Aliasing — where it appears
Named by 3 essays across 2 fields — each of them below, with the objects they name alongside it.
The window that is even in the wrong currency
A window of four thousand arrivals in eight blocks retires a block every 5.1 seconds on a steady stream and anywhere between 0.57 and 14.8 seconds on a stream whose rate moves. The structure cannot tell, because it is counting arrivals, and the alert written against it is in seconds.
The boundary that hides the burst
A window whose blocks hold five hundred and twelve arrivals reports a perfectly even stream — every block the same duration to the tick — while the arrivals it is retiring have an index of dispersion of 0.57. Move the block to a hundred and twenty-five and the same stream varies by 1.8 times.
The sampler that cannot alias
A block window's boundary fires on an arrival count, and a stream whose burst repeats every sixty-four arrivals is reported as perfectly even by a block of five hundred and twelve. A quantile summary compresses on an update count, which is the same arrangement. Swept against three periodic value processes and their shuffles, it does not alias — and the reason is one line of arithmetic rather than a lucky sweep.
Named alongside it
The objects these essays reach for when they reach for this one.
Arrival processBurstinessMeasurementSliding windowTemporal resolutionClock resolutionCommensurabilityExpiryExponential histogramFailure modeOccupancySampling