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Dynamic time warping

About: Dynamic time warping is a research topic. Over the lifetime, 6013 publications have been published within this topic receiving 133130 citations.


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TL;DR: The aim of this study was to develop an autonomous and intelligent system for residential water end-use classification that could interface with customers and water business managers via a user-friendly web-based application.
Abstract: Intelligent metering technology combined with advanced numerical techniques enable a paradigm shift in the current level of water consumption information provision that is available to the customer and the water business. The aim of this study was to develop an autonomous and intelligent system for residential water end-use classification that could interface with customers and water business managers via a user-friendly web-based application. Water flow data collected directly from smart water meters includes both single (e.g., a shower event occurring alone) and combined (i.e., an event that comprises several overlapping single events) water end use events. The authors recently developed intelligent algorithms to solve the complex problem of autonomously categorising residential water consumption data into a registry of single and combined events using a hybrid combination of techniques including Hidden Markov Model (HMM), Dynamic Time Warping (DTW) algorithm, time-of-day probability functions, threshold values and various physical features. However, the issue still remained, which is the focus of this current paper, on how to integrate self-learning functionality into the visioned expert system, in order that it can learn from newly collected datasets from different cities, regions and countries, to that collected for the training data. Such versatility and adaptive capacity is essential to make the expert system widely applicable. Through applying alternate forms of HMM and DTW in association with a frequency analysis technique, a suitable self-learning methodology was formulated and tested on three independent households located in Melbourne, Australia with a prediction accuracy of between 80% and 90% for the major end-use categories. The three principle flow data processing modules (i.e., single and combined event recognition and self-learning function) were integrated into a prototype software application for performing autonomous water end-use analysis and its functionality is presented in the latter sections of this paper. The developed expert system has profound implications for government, water businesses and consumers, seeking to better manage precious urban water resources.

58 citations

Journal ArticleDOI
TL;DR: The objective of this study was the development of a remote monitoring system to monitor and detect simple motor seizures using accelerometer-based kinematic sensors from subjects undergoing medication titration at the Beth Israel Deaconess Medical Center.
Abstract: The objective of this study was the development of a remote monitoring system to monitor and detect simple motor seizures. Using accelerometer-based kinematic sensors, data were gathered from subjects undergoing medication titration at the Beth Israel Deaconess Medical Center. Over the course of the study, subjects repeatedly performed a predefined set of instrumental activities of daily living (iADLs). During the monitoring sessions, EEG and video data were also recorded and provided the gold standard for seizure detection. To distinguish seizure events from iADLs, we developed a template matching algorithm. Considering the unique signature of seizure events and the inherent temporal variability of seizure types across subjects, we incorporated a customized mass-spring template into the dynamic time warping algorithm. We then ported this algorithm onto a commercially available internet tablet and developed our body sensor network on the Mercury platform. We designed several policies on this platform to compare the tradeoffs between feature calculation, raw data transmission, and battery lifetime. From a dataset of 21 seizures, the sensitivity for our template matching algorithm was found to be 0.91 and specificity of 0.84. We achieved a battery lifetime of 10.5 h on the Mercury platform.

58 citations

Journal ArticleDOI
TL;DR: Deep Canonical Time Warping is presented, a method that automatically learns non-linear representations of multiple time-series that are maximally correlated in a shared subspace, and temporally aligned, and significantly outperform state-of-the-art methods in temporal alignment.
Abstract: Machine learning algorithms for the analysis of time-series often depend on the assumption that utilised data are temporally aligned. Any temporal discrepancies arising in the data is certain to lead to ill-generalisable models, which in turn fail to correctly capture properties of the task at hand. The temporal alignment of time-series is thus a crucial challenge manifesting in a multitude of applications. Nevertheless, the vast majority of algorithms oriented towards temporal alignment are either applied directly on the observation space or simply utilise linear projections-thus failing to capture complex, hierarchical non-linear representations that may prove beneficial, especially when dealing with multi-modal data (e.g., visual and acoustic information). To this end, we present Deep Canonical Time Warping (DCTW), a method that automatically learns non-linear representations of multiple time-series that are (i) maximally correlated in a shared subspace, and (ii) temporally aligned. Furthermore, we extend DCTW to a supervised setting, where during training, available labels can be utilised towards enhancing the alignment process. By means of experiments on four datasets, we show that the representations learnt significantly outperform state-of-the-art methods in temporal alignment, elegantly handling scenarios with heterogeneous feature sets, such as the temporal alignment of acoustic and visual information.

58 citations

Journal ArticleDOI
TL;DR: A variant of DTW based algorithm referred to as non-segmental DTW (NS-DTW) is used, with a computational upper bound of O (mn) and analyzed the performance of QbE-STD with Gaussian posteriorgrams obtained from spectral and temporal features of the speech signal, showing that frequency domain linear prediction cepstral coefficients can be used as an alternative to traditional spectral parameters.
Abstract: The task of query-by-example spoken term detection (QbE-STD) is to find a spoken query within spoken audio data. Current state-of-the-art techniques assume zero prior knowledge about the language of the audio data, and thus explore dynamic time warping (DTW) based techniques for the QbE-STD task. In this paper, we use a variant of DTW based algorithm referred to as non-segmental DTW (NS-DTW), with a computational upper bound of O (mn) and analyze the performance of QbE-STD with Gaussian posteriorgrams obtained from spectral and temporal features of the speech signal. The results show that frequency domain linear prediction cepstral coefficients, which capture the temporal dynamics of the speech signal, can be used as an alternative to traditional spectral parameters such as linear prediction cepstral coefficients, perceptual linear prediction cepstral coefficients and Mel-frequency cepstral coefficients. We also introduce another variant of NS-DTW called fast NS-DTW (FNS-DTW) which uses reduced feature vectors for search. With a reduction factor of α ∈ ℕ, we show that the computational upper bound for FNS-DTW is O(mn/(α2)) which is faster than NS-DTW.

57 citations

Journal ArticleDOI
TL;DR: A SIM is developed that models the time transformations as random, flexible, monotone functions and is applied to speech movement data from the University of Wisconsin X‐ray microbeam speech production project and is motivated byspeech movement data.
Abstract: Methods for modeling sets of complex curves where the curves must be aligned in time (or in another continuous predictor) fall into the general class of functional data analysis and include self-modeling regression and time-warping procedures. Self-modeling regression (SEMOR), also known as a shape invariant model (SIM), assumes the curves have a common shape, modeled nonparametrically, and curve-specific differences in amplitude and timing, traditionally modeled by linear transformations. When curves contain multiple features that need to be aligned in time, SEMOR may be inadequate since a linear time transformation generally cannot align more than one feature. Time warping procedures focus on timing variability and on finding flexible time warps to align multiple data features. We draw on these methods to develop a SIM that models the time transformations as random, flexible, monotone functions. The model is motivated by speech movement data from the University of Wisconsin X-ray microbeam speech production project and is applied to these data to test the effect of different speaking conditions on the shape and relative timing of movement profiles.

57 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023236
2022471
2021341
2020416
2019420
2018377