Hi,
The indicators are totally different. Maybe the EMA1 and DECEMA5 is similar but DECEMA is more faster.
DECEMA is "DEMA@10".
It's a a very fast trend indicator with very low lag ( to be used together with an EMA to fast identify changing of direction/trend on prices.

I was using it with the Channel Trading system to identify the change of the Channel.

I'm still trying to find a good CROSS system for this indicator because i think that is good.