Error and Anomaly Detection for Intra-Participant Time-Series Data
Taylor and Francis
MetadataShow full item record
Identification of errors or anomalous values, collectively considered outliers, assists in exploring data or through removing outliers improves the statistical analysis. In biomechanics, outlier detection methods have explored the ‘shape’ of the entire cycles, although exploring fewer points using a ‘moving-window’ may be advantageous. Hence, the aim was to develop a moving-window based method for detecting trials with outliers in intra-participant time-series data. The test data were the angles and displacements for the strides or cycles (mean 38 cycles) from treadmill running, with outliers detected through two-stages. Stage-1 was a one-dimensional (spatial) outlier detection at each time-point, where any data-value of a scaled median-absolute-deviation away from the median at that time-point led to removing that cycle. Stage-2 was a two-dimensional (spatial-temporal) outlier detection of a moving-window-standard-deviation (mwSD) across cycles and across the moving-window size (size of ± 0, 1, 2 or 3 time-points), where any data-value greater than the scaled mwSD led to removing that cycle. Scaling was performed using the t-statistic for three significance levels of 0.01, 0.001 or 0.0001. Fewer cycles were removed with smaller scaling and smaller window size. Appropriate settings were stage-1 scaling of 0.0001 (mean 3.5 cycles removed) and stage-2 scaling of 0.01 with a moving-window size of 1 (mean 2.6 cycles removed). Settings in the supplied Matlab code should be customised to each data set, and trials with outliers assessed to justify whether to retain or remove those trials. The method provides an effective method to identify trials with outliers in intra-participant time-series data.
Mullineaux, David R. and Irwin, Gareth (2017) 'Error and anomaly detection for intra-participant time-series data', International Biomechanics, 4 (1). pp. 28-35.
This article was published open access in International Biomechanics on 10 July 2017 (online), available at http://dx.doi.org/10.1080/23335432.2017.1348913
Cardiff Metropolitan University (Grant ID: Cardiff Metropolian (Internal))
- Sport Research Groups 
Showing items related by title, author, subject and abstract.
Driscoll, Mark B. (Cardiff Metropolitan University, 2002)This work describes an amplification system, which can greatly increase the amount of ATP available for detection by bioluminescent methods, increasing the sensitivity. The system makes use of an enzyme, adenylate kinase ...
Okhiria, Olusola Adeola (University of WalesCardiff School of Health Sciences, 2010)Biofilms have long been implicated in persistent infections and have recently been associated with chronic wounds. The role of bacteria in wounds is not yet fully understood and their ability to form biofilm is yet to be ...
Experiences of households using integrated malaria prevention in two rural communities in Wakiso district, Uganda: a qualitative study Musoke, David; Karani, George; Ndejjo, Rawlence; Okui, Peter; Musoke, Miph B (BioMed Central, 2016-06-07)Background The integrated approach to malaria prevention which advocates use of several methods in a holistic manner is being explored to complement existing strategies. A pilot project that promoted integrated malaria ...