Reservoir Dynamic Interpretability for Time Series Prediction: A Permutation Entropy View

An echo state network (ESN) is an efficient recurrent neural network (RNN) that is widely used in time series prediction tasks due to its simplicity and low training cost. However, the “black-box” nature of reservoirs hinders the development of ESN. Although a large number of studies have concentrat...

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Main Authors: Xiaochuan Sun, Mingxiang Hao, Yutong Wang, Yu Wang, Zhigang Li, Yingqi Li
Format: Article
Language:English
Published: MDPI AG 2022-11-01
Series:Entropy
Subjects:
Online Access:https://www.mdpi.com/1099-4300/24/12/1709
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author Xiaochuan Sun
Mingxiang Hao
Yutong Wang
Yu Wang
Zhigang Li
Yingqi Li
author_facet Xiaochuan Sun
Mingxiang Hao
Yutong Wang
Yu Wang
Zhigang Li
Yingqi Li
author_sort Xiaochuan Sun
collection DOAJ
description An echo state network (ESN) is an efficient recurrent neural network (RNN) that is widely used in time series prediction tasks due to its simplicity and low training cost. However, the “black-box” nature of reservoirs hinders the development of ESN. Although a large number of studies have concentrated on reservoir interpretability, the perspective of reservoir modeling is relatively single, and the relationship between reservoir richness and reservoir projection capacity has not been effectively established. To tackle this problem, a novel reservoir interpretability framework based on permutation entropy (PE) theory is proposed in this paper. In structure, this framework consists of reservoir state extraction, PE modeling, and PE analysis. Based on these, the instantaneous reservoir states and neuronal time-varying states are extracted, which are followed by phase space reconstruction, sorting, and entropy calculation. Firstly, the obtained instantaneous state entropy (ISE) and global state entropy (GSE) can measure reservoir richness for interpreting good reservoir projection capacity. On the other hand, the multiscale complexity–entropy analysis of global and neuron-level reservoir states is performed to reveal more detailed dynamics. Finally, the relationships between ESN performance and reservoir dynamic are investigated via Pearson correlation, considering different prediction steps and time scales. Experimental evaluations on several benchmarks and real-world datasets demonstrate the effectiveness and superiority of the proposed reservoir interpretability framework.
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spelling doaj.art-d05c00a2dc3c46a39045af7278ccf0d32023-11-24T14:41:33ZengMDPI AGEntropy1099-43002022-11-012412170910.3390/e24121709Reservoir Dynamic Interpretability for Time Series Prediction: A Permutation Entropy ViewXiaochuan Sun0Mingxiang Hao1Yutong Wang2Yu Wang3Zhigang Li4Yingqi Li5College of Artificial Intelligence, North China University of Science and Technology, Bohai Road, Tangshan 063210, ChinaCollege of Artificial Intelligence, North China University of Science and Technology, Bohai Road, Tangshan 063210, ChinaCollege of Artificial Intelligence, North China University of Science and Technology, Bohai Road, Tangshan 063210, ChinaCollege of Artificial Intelligence, North China University of Science and Technology, Bohai Road, Tangshan 063210, ChinaCollege of Artificial Intelligence, North China University of Science and Technology, Bohai Road, Tangshan 063210, ChinaSchool of Computer and Communication Engineering, University of Science and Technology Beijing, Beijing 100083, ChinaAn echo state network (ESN) is an efficient recurrent neural network (RNN) that is widely used in time series prediction tasks due to its simplicity and low training cost. However, the “black-box” nature of reservoirs hinders the development of ESN. Although a large number of studies have concentrated on reservoir interpretability, the perspective of reservoir modeling is relatively single, and the relationship between reservoir richness and reservoir projection capacity has not been effectively established. To tackle this problem, a novel reservoir interpretability framework based on permutation entropy (PE) theory is proposed in this paper. In structure, this framework consists of reservoir state extraction, PE modeling, and PE analysis. Based on these, the instantaneous reservoir states and neuronal time-varying states are extracted, which are followed by phase space reconstruction, sorting, and entropy calculation. Firstly, the obtained instantaneous state entropy (ISE) and global state entropy (GSE) can measure reservoir richness for interpreting good reservoir projection capacity. On the other hand, the multiscale complexity–entropy analysis of global and neuron-level reservoir states is performed to reveal more detailed dynamics. Finally, the relationships between ESN performance and reservoir dynamic are investigated via Pearson correlation, considering different prediction steps and time scales. Experimental evaluations on several benchmarks and real-world datasets demonstrate the effectiveness and superiority of the proposed reservoir interpretability framework.https://www.mdpi.com/1099-4300/24/12/1709echo state networktime series predictioninterpretabilityPEreservoir richnessprojection capability
spellingShingle Xiaochuan Sun
Mingxiang Hao
Yutong Wang
Yu Wang
Zhigang Li
Yingqi Li
Reservoir Dynamic Interpretability for Time Series Prediction: A Permutation Entropy View
Entropy
echo state network
time series prediction
interpretability
PE
reservoir richness
projection capability
title Reservoir Dynamic Interpretability for Time Series Prediction: A Permutation Entropy View
title_full Reservoir Dynamic Interpretability for Time Series Prediction: A Permutation Entropy View
title_fullStr Reservoir Dynamic Interpretability for Time Series Prediction: A Permutation Entropy View
title_full_unstemmed Reservoir Dynamic Interpretability for Time Series Prediction: A Permutation Entropy View
title_short Reservoir Dynamic Interpretability for Time Series Prediction: A Permutation Entropy View
title_sort reservoir dynamic interpretability for time series prediction a permutation entropy view
topic echo state network
time series prediction
interpretability
PE
reservoir richness
projection capability
url https://www.mdpi.com/1099-4300/24/12/1709
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