Abstract—Due to its various applications, time-series classifi-
cation is a prominent research topic in data mining and computational
intelligence. The simple k-NN classifier using dynamic
time warping (DTW) distance had been shown to be competitive
to other state-of-the art time-series classifiers. In our research,
however, we observed that a single fixed choice for the number of
nearest neighbors k may lead to suboptimal performance. This
is due to the complexity of time-series data, especially because
the characteristic of the data may vary from region to region.
Therefore, local adaptations of the classification algorithm is
required. In order to address this problem in a principled way by,
in this paper we introduce individual quality (IQ) estimation. This
refers to estimating the expected classification accuracy for each
time series and each k individually. Based on the IQ estimations
we combine the classification results of several k-NN classifiers
as final prediction. In our framework of IQ, we develop two
time-series classification algorithms, IQ-MAX and IQ-WV. In our
experiments on 35 commonly used benchmark data sets, we show
that both IQ-MAX and IQ-WV outperform two baselines.
Index Terms—time series; classification; individual quality (IQ)