It is an indicator that displays a trade sign, before the exponential smooth moving average line crosses the golden cross and the dead cross.
SHORT indicates the beginning of the downward trend and LONG indicates the beginning of the upward trend.
Long EMA should be longer than Short EMA.
The reason why we use exponential smooth moving averages is that they are generally advantageous, because they give trade signs faster than simple moving averages and weighted moving averages.