Homogeneity tests for functional data based on depth-depth plots with chemical applications

Calle-Saldarriaga, Alejandro; Laniado, Henry; Zuluaga, Francisco; Leiva, Víctor

doi:10.1016/j.chemolab.2021.104420

Cited by 7 publications

(13 citation statements)

References 55 publications

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“…Analysis of the ERG waveform using wavelet functions [as well as other signal analysis techniques such as Variable Frequency Complex Demodulation (VFCDM), ( Chon et al, 2009 ), or Functional Data Analysis ( Calle-Saldarriaga et al, 2021 )] could provide better characterization of the heterogeneity inherent within the neurodevelopmental disorders that share common clinical traits ( Thapar et al, 2017 ; Molloy and Gallagher, 2021 ). Of these, VFCDM can provide one of the highest time-frequency resolutions ( Chon et al, 2009 ) and has been used to analyze other physiological signals ( Wang et al, 2006 ; Siu et al, 2009 , Posada-Quintero et al, 2016 ; Hossain et al, 2021 ).…”

Section: Discussionmentioning

confidence: 99%

Discrete Wavelet Transform Analysis of the Electroretinogram in Autism Spectrum Disorder and Attention Deficit Hyperactivity Disorder

et al. 2022

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BackgroundTo evaluate the electroretinogram waveform in autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) using a discrete wavelet transform (DWT) approach.MethodsA total of 55 ASD, 15 ADHD and 156 control individuals took part in this study. Full field light-adapted electroretinograms (ERGs) were recorded using a Troland protocol, accounting for pupil size, with five flash strengths ranging from –0.12 to 1.20 log photopic cd.s.m–2. A DWT analysis was performed using the Haar wavelet on the waveforms to examine the energy within the time windows of the a- and b-waves and the oscillatory potentials (OPs) which yielded six DWT coefficients related to these parameters. The central frequency bands were from 20–160 Hz relating to the a-wave, b-wave and OPs represented by the coefficients: a20, a40, b20, b40, op80, and op160, respectively. In addition, the b-wave amplitude and percentage energy contribution of the OPs (%OPs) in the total ERG broadband energy was evaluated.ResultsThere were significant group differences (p < 0.001) in the coefficients corresponding to energies in the b-wave (b20, b40) and OPs (op80 and op160) as well as the b-wave amplitude. Notable differences between the ADHD and control groups were found in the b20 and b40 coefficients. In contrast, the greatest differences between the ASD and control group were found in the op80 and op160 coefficients. The b-wave amplitude showed both ASD and ADHD significant group differences from the control participants, for flash strengths greater than 0.4 log photopic cd.s.m–2 (p < 0.001).ConclusionThis methodological approach may provide insights about neuronal activity in studies investigating group differences where retinal signaling may be altered through neurodevelopment or neurodegenerative conditions. However, further work will be required to determine if retinal signal analysis can offer a classification model for neurodevelopmental conditions in which there is a co-occurrence such as ASD and ADHD.

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Section: Discussionmentioning

confidence: 99%

Discrete Wavelet Transform Analysis of the Electroretinogram in Autism Spectrum Disorder and Attention Deficit Hyperactivity Disorder

et al. 2022

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“…However, we remark some limitations of our models and the proposed methodology. For example, diverse phenomena frequently provide other types of data to those analyzed in this study, such as censored, functional, spatial, and temporal data, as well as structures of measurement errors, and partial least squares, all of which are suitable to be studied to increase the predictive capability in the modeling; see [37][38][39][40][41]. Then, it is necessary to formulate new models based on our approach to study these phenomena in such types of data and modeling structures.…”

Section: Discussionmentioning

confidence: 99%

A New Quantile Regression Model and Its Diagnostic Analytics for a Weibull Distributed Response with Applications

et al. 2021

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Standard regression models focus on the mean response based on covariates. Quantile regression describes the quantile for a response conditioned to values of covariates. The relevance of quantile regression is even greater when the response follows an asymmetrical distribution. This relevance is because the mean is not a good centrality measure to resume asymmetrically distributed data. In such a scenario, the median is a better measure of the central tendency. Quantile regression, which includes median modeling, is a better alternative to describe asymmetrically distributed data. The Weibull distribution is asymmetrical, has positive support, and has been extensively studied. In this work, we propose a new approach to quantile regression based on the Weibull distribution parameterized by its quantiles. We estimate the model parameters using the maximum likelihood method, discuss their asymptotic properties, and develop hypothesis tests. Two types of residuals are presented to evaluate the model fitting to data. We conduct Monte Carlo simulations to assess the performance of the maximum likelihood estimators and residuals. Local influence techniques are also derived to analyze the impact of perturbations on the estimated parameters, allowing us to detect potentially influential observations. We apply the obtained results to a real-world data set to show how helpful this type of quantile regression model is.

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“…One of the standard problems in statistics is determining if two samples come from the same population [12]. the homogeneity testing shows the following results.…”

Section: Homogeneity Testmentioning

confidence: 99%

The effect of the MIG welding technique on the tensible strength results for cross members making in electric cars with ST 60 materials

Nugraha

Samsudi

2022

JEATech

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This study aims to determine the chemical composition and tensile strength of ST60 materials in MIG (Metal Inert Gas) welding for the manufacture of electric car cross members and to reveal the effect of the welding technique on the welding results. The material was medium carbon steel with a thickness of 5 mm for each. The welding was done with MIG welding using a single 90-degree V joint with a current of 150 A. The welding techniques were straight, circular, and zigzag. The results showed a significant effect in circular welding with the largest average of 152,314 kg/mm2, while straight welding showed the lowest average tensile strength of 373.793 kg/mm2. The circular welding also had the strength value with the highest tensile strength of 526,107 kg/mm2.

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Homogeneity tests for functional data based on depth-depth plots with chemical applications

Cited by 7 publications

References 55 publications

Discrete Wavelet Transform Analysis of the Electroretinogram in Autism Spectrum Disorder and Attention Deficit Hyperactivity Disorder

Discrete Wavelet Transform Analysis of the Electroretinogram in Autism Spectrum Disorder and Attention Deficit Hyperactivity Disorder

A New Quantile Regression Model and Its Diagnostic Analytics for a Weibull Distributed Response with Applications

The effect of the MIG welding technique on the tensible strength results for cross members making in electric cars with ST 60 materials

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