The Stochastic Oscillator is a momentum indicator comparing the price to the range of its prices over a certain period of time. The sensitivity of the oscillator to market movements is reducible by adjusting that time period or by taking a Moving Average of the result.
Hull Moving Average has been added in order to reduce the false signals. Hull average is used prior to stochastic calculation thus filtering the prices before they are used in the stochastic calculation. This method is used since it adds much less lag than if the smoothing of the already calculated stochastic value would be used.