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Learning Time Series Segmentation Models from Temporally Imprecise Labels
Proceedings of the 34th Conference on Uncertainty in Artificial Intelligence, PMLR R16:134-143, 2018.
Abstract
This paper considers the problem of learning time series segmentation models when the la- beled data are subject to temporal uncertainty or noise. Our approach augments the semi- Markov conditional random field (semi-CRF) model with a probabilistic model of the label observation process. This augmentation allows us to estimate the parameters of the semi-CRF from timestamps corresponding roughly to the occurrence of transitions between segments. We show how exact marginal inference can be performed in the augmented model in polyno- mial time, enabling learning based on marginal likelihood maximization. Our experiments on two activity detection problems show that the proposed approach can learn models from tem- porally imprecise labels, and can successfully refine imprecise segmentations through poste- rior inference. Finally, we show how inference complexity can be reduced by a factor of 40 using static and model-based pruning of the inference dynamic program.