Abstract:
This paper deals with Holt- Winter's Exponential Smoohting model
which includes how to seek parameter alfa , beta and gamma combination that optimize model accuracy measurement. Based on our literature study
on three references, there are three different models which differ each
other on the determination of the initial value. Models are applied on
test data [Hanke, 1998: p. 126] and US-Rupiah foreign exchange data.
Their accuracies are compared by [Sukmana, 2005] using the same
data set but with XII-ARIMA model. Determination of the parameter
iteratively by taking one best pair from 125000 possible pairs gives the
best result. Model I [De Lurgio, 1998] gives the best accuracy
compared with other Holt-Winter models. Model Holt-Winter gives an
accurate result only if the data consist of trend component and
seasonal. Compared with XII-ARIMA model, the accuracy of this
model is not quite good, however the computaion is easier.
