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When to Classify Events in Open Times Series?
Proceedings of The 14th Asian Conference on Machine
Learning, PMLR 189:1-16, 2023.
Abstract
In numerous applications, for instance in predictive
maintenance, there is a pression to predict events
ahead of time with as much accuracy as possible
while not delaying the decision unduly. This
translates in the optimization of a trade-off
between earliness and accuracy of the decisions,
that has been the subject of research for time
series of finite length and with a unique label. And
this has led to powerful algorithms for Early
Classification of Time Series (ECTS). This paper,
for the first time, investigates such a trade-off
when events of different classes occur in a
streaming fashion, with no predefined end. In the
Early Classification in Open Time Series problem
(ECOTS), the task is to predict events, i.e. their
class and time interval, at the moment that
optimizes the accuracy vs. earliness
trade-off. Interestingly, we find that ECTS
algorithms can be sensibly adapted in a principled
way to this new problem. We illustrate our
methodology by transforming two state-of-the-art
ECTS algorithms for the ECOTS scenario.Among the
wide variety of applications that this new approach
opens up, we develop here a predictive maintenance
use case that optimizes alarm triggering times, thus
demonstrating the power of this new approach.