The Smoothed Moving Average (SMMA) is similar to the Simple Moving Average (SMA), in that it aims to reduce noise rather than reduce lag. The indicator takes all prices into account & uses a long lookback period. Old prices are never removed from the calculation, but they have only a minimal impact on the Moving Average due to a low assigned weight. By reducing the noise it removes fluctuations & plots the prevailing trend. The SMMA can be used to confirm trends & define areas of support & resistance.
The double exponential moving average (DEMA) is a technical indicator devised to reduce the lag produced by a traditional moving average. Technical traders use it to lessen the amount of "noise" that can distort the movements on a price chart.