7 research outputs found

    Online pattern recognition in subsequence time series clustering

    Get PDF
    One of the open issues in the context of subsequence time series clustering is online pattern recognition. There are different fields in this clustering such as e-commerce, outlier detection, speech recognition, biological systems, DNA recognition, and text mining. Among these fields pattern recognition is one the essential concept. To implement the idea of online pattern recognition, we choose sequences of ECG data as a subsequence time series data. Additionally, using ECG data can help to interpret heart activity for finding heart diseases. This paper will offer a way to generate online pattern recognition in subsequence time series clustering in order to have a runtime results

    F4: An All-Purpose Tool for Multivariate Time Series Classification

    Get PDF
    This article belongs to the Special Issue Data Mining for Temporal Data Analysis[Abstract] We propose Fast Forest of Flexible Features (F4), a novel approach for classifying multivariate time series, which is aimed to discriminate between underlying generating processes. This goal has barely been addressed in the literature. F4 consists of two steps. First, a set of features based on the quantile cross-spectral density and the maximum overlap discrete wavelet transform are extracted from each series. Second, a random forest is fed with the extracted features. An extensive simulation study shows that F4 outperforms some powerful classifiers in a wide variety of situations, including stationary and nonstationary series. The proposed method is also capable of successfully discriminating between electrocardiogram (ECG) signals of healthy subjects and those with myocardial infarction condition. Additionally, despite lacking shape-based information, F4 attains state-of-the-art results in some datasets of the University of East Anglia (UEA) multivariate time series classification archive.This research has been supported by the Ministerio de Economía y Competitividad (MINECO) grants MTM2017-82724-R and PID2020-113578RB-100, the Xunta de Galicia (Grupos de Referencia Competitiva ED431C-2020-14), and the Centro de Investigación del Sistema Universitario de Galicia, “CITIC” grant ED431G 2019/01; all of them through the European Regional Development Fund (ERDF). This work has received a discount in publication fees by Universidade da Coruña/CISUGXunta de Galicia; ED431C-2020-14Xunta de Galicia; ED431G 2019/0

    A Review of Subsequence Time Series Clustering

    Get PDF
    Clustering of subsequence time series remains an open issue in time series clustering. Subsequence time series clustering is used in different fields, such as e-commerce, outlier detection, speech recognition, biological systems, DNA recognition, and text mining. One of the useful fields in the domain of subsequence time series clustering is pattern recognition. To improve this field, a sequence of time series data is used. This paper reviews some definitions and backgrounds related to subsequence time series clustering. The categorization of the literature reviews is divided into three groups: preproof, interproof, and postproof period. Moreover, various state-of-the-art approaches in performing subsequence time series clustering are discussed under each of the following categories. The strengths and weaknesses of the employed methods are evaluated as potential issues for future studies

    Signal processing and analytics of multimodal biosignals

    Get PDF
    Ph. D. ThesisBiosignals have been extensively studied by researchers for applications in diagnosis, therapy, and monitoring. As these signals are complex, they have to be crafted as features for machine learning to work. This begs the question of how to extract features that are relevant and yet invariant to uncontrolled extraneous factors. In the last decade or so, deep learning has been used to extract features from the raw signals automatically. Furthermore, with the proliferation of sensors, more raw signals are now available, making it possible to use multi-view learning to improve on the predictive performance of deep learning. The purpose of this work is to develop an effective deep learning model of the biosignals and make use of the multi-view information in the sequential data. This thesis describes two proposed methods, namely: (1) The use of a deep temporal convolution network to provide the temporal context of the signals to the deeper layers of a deep belief net. (2) The use of multi-view spectral embedding to blend the complementary data in an ensemble. This work uses several annotated biosignal data sets that are available in the open domain. They are non-stationary, noisy and non-linear signals. Using these signals in their raw form without feature engineering will yield poor results with the traditional machine learning techniques. By passing abstractions that are more useful through the deep belief net and blending the complementary data in an ensemble, there will be improvement in performance in terms of accuracy and variance, as shown by the results of 10-fold validations.Nanyang Polytechni
    corecore