Abstract: Early classification on time series is more and more significant in the field of time series data ming.As the high dimension of time series data,it is of highly necessary to choose an efficient and appreciate dimensionality reduction method in the practical application of early classification on time series.Thus,this paper aimed at applying piecewise aggregate approximation to time series data,and then implemented early classification in lower dimension.In addition,through making comparison with some existing methods,the experiments were carried on in forty-three datasets.The experimental result indicates that this proposal is better than other existing methods in accuracy,earliness and reliability.

Key words: Time series,Early classification,Dimensionality reduction,Piecewise aggregate approximation