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Keywords = adaptive complex Group Lasso

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17 pages, 4441 KiB  
Article
Research on Aviation Safety Prediction Based on Variable Selection and LSTM
by Hang Zeng, Jiansheng Guo, Hongmei Zhang, Bo Ren and Jiangnan Wu
Sensors 2023, 23(1), 41; https://doi.org/10.3390/s23010041 - 21 Dec 2022
Cited by 6 | Viewed by 2131 | Correction
Abstract
Accurate prediction of aviation safety levels is significant for the efficient early warning and prevention of incidents. However, the causal mechanism and temporal character of aviation accidents are complex and not fully understood, which increases the operation cost of accurate aviation safety prediction. [...] Read more.
Accurate prediction of aviation safety levels is significant for the efficient early warning and prevention of incidents. However, the causal mechanism and temporal character of aviation accidents are complex and not fully understood, which increases the operation cost of accurate aviation safety prediction. This paper adopts an innovative statistical method involving a least absolute shrinkage and selection operator (LASSO) and long short-term memory (LSTM). We compiled and calculated 138 monthly aviation insecure events collected from the Aviation Safety Reporting System (ASRS) and took minor accidents as the predictor. Firstly, this paper introduced the group variables and the weight matrix into LASSO to realize the adaptive variable selection. Furthermore, it took the selected variable into multistep stacked LSTM (MSSLSTM) to predict the monthly accidents in 2020. Finally, the proposed method was compared with multiple existing variable selection and prediction methods. The results demonstrate that the RMSE (root mean square error) of the MSSLSTM is reduced by 41.98%, compared with the original model; on the other hand, the key variable selected by the adaptive spare group lasso (ADSGL) can reduce the elapsed time by 42.67% (13 s). This shows that aviation safety prediction based on ADSGL and MSSLSTM can improve the prediction efficiency of the model while keeping excellent generalization ability and robustness. Full article
(This article belongs to the Special Issue Vehicle Autonomy, Safety, and Security via Mobile Crowdsensing)
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<p>Flow chat of the ADSGL-MSSLSTM method.</p>
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<p>The network architecture of LSTM.</p>
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<p>Sequence diagram for white noise.</p>
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<p>Aviation safety prediction model based on MSSLSTM.</p>
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<p>Changes of the validation MSE under the different relaxation variables.</p>
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<p>Lasso fitting coefficient tracer diagram as α takes 0.1.</p>
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<p>The absolute values of compressed regression coefficients as <span class="html-italic">α</span> set to (<b>a</b>) 0.1, (<b>b</b>) 0.3, (<b>c</b>) 0.5, (<b>d</b>) 0.8.</p>
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<p>Sequence diagram for (<b>a</b>) MA, (<b>b</b>), A (<b>c</b>) CP, (<b>d</b>) P.</p>
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<p>Changes of training accuracy under different number of layers.</p>
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<p>Changes of training accuracy under different number of nodes in the (<b>a</b>) 1st and 2nd hidden layer, (<b>b</b>) 3rd and 4th hidden layer.</p>
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<p>Comparison of the predictive model results.</p>
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<p>The RMSE distribution diagram of the ten-time experiments.</p>
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18 pages, 377 KiB  
Article
Pressure Injury Link to Entropy of Abdominal Temperature
by Nikhil Padhye, Denise Rios, Vaunette Fay and Sandra K. Hanneman
Entropy 2022, 24(8), 1127; https://doi.org/10.3390/e24081127 - 15 Aug 2022
Cited by 2 | Viewed by 2236
Abstract
This study examined the association between pressure injuries and complexity of abdominal temperature measured in residents of a nursing facility. The temperature served as a proxy measure for skin thermoregulation. Refined multiscale sample entropy and bubble entropy were used to measure the irregularity [...] Read more.
This study examined the association between pressure injuries and complexity of abdominal temperature measured in residents of a nursing facility. The temperature served as a proxy measure for skin thermoregulation. Refined multiscale sample entropy and bubble entropy were used to measure the irregularity of the temperature time series measured over two days at 1-min intervals. Robust summary measures were derived for the multiscale entropies and used in predictive models for pressure injuries that were built with adaptive lasso regression and neural networks. Both types of entropies were lower in the group of participants with pressure injuries (n=11) relative to the group of non-injured participants (n=15). This was generally true at the longer temporal scales, with the effect peaking at scale τ=22 min for sample entropy and τ=23 min for bubble entropy. Predictive models for pressure injury on the basis of refined multiscale sample entropy and bubble entropy yielded 96% accuracy, outperforming predictions based on any single measure of entropy. Combining entropy measures with a widely used risk assessment score led to the best prediction accuracy. Complexity of the abdominal temperature series could therefore serve as an indicator of risk of pressure injury. Full article
(This article belongs to the Section Multidisciplinary Applications)
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<p>Temperature time series data are shown over a period of 68 h, along with detected autoregressive anomalies that aided in identification of the active section with abdominal temperature measurements.</p>
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<p>Refined multiscale sample entropy (<math display="inline"><semantics> <mrow> <mi>m</mi> <mo>=</mo> <mn>3</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>r</mi> <mo>=</mo> <mn>0.15</mn> </mrow> </semantics></math>) at temporal scales ranging from 1 to 25 min. Error bars depict the standard error in the control and pressure injury groups.</p>
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<p>Refined multiscale bubble entropy (<math display="inline"><semantics> <mrow> <mi>m</mi> <mo>=</mo> <mn>3</mn> </mrow> </semantics></math>) at temporal scales ranging from 1 to 25 min. Error bars depict the standard error in the control and pressure injury groups.</p>
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<p>Effect sizes, i.e., standardized mean differences (Cohen’s <span class="html-italic">d</span>) between control and pressure injury groups, at each temporal scale for refined multiscale sample entropy and bubble entropy. Filled circles indicate effects that satisfied <math display="inline"><semantics> <mrow> <mi>p</mi> <mo>&lt;</mo> <mn>0.05</mn> </mrow> </semantics></math>.</p>
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<p>Accuracy of classification by adaptive lasso (model <span class="html-italic">M</span>1) and neural network (model <span class="html-italic">N</span>1) for prediction of pressure injury from the SampEn scaling exponent and BubbEn requisite AUC. Accuracy is shown separately for predicting pressure injury cases (red) and control cases (blue).</p>
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<p>Structure of the neural network for prediction of pressure injuries from two entropy measures and the Braden scale score. The different colors of the nodes denote Gaussian and hyperbolic tangent activation functions.</p>
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20 pages, 4456 KiB  
Article
Integrating Health Data-Driven Machine Learning Algorithms to Evaluate Risk Factors of Early Stage Hypertension at Different Levels of HDL and LDL Cholesterol
by Pen-Chih Liao, Ming-Shu Chen, Mao-Jhen Jhou, Tsan-Chi Chen, Chih-Te Yang and Chi-Jie Lu
Diagnostics 2022, 12(8), 1965; https://doi.org/10.3390/diagnostics12081965 - 14 Aug 2022
Cited by 14 | Viewed by 3247
Abstract
Purpose: Cardiovascular disease (CVD) is a major worldwide health burden. As the risk factors of CVD, hypertension, and hyperlipidemia are most mentioned. Early stage hypertension in the population with dyslipidemia is an important public health hazard. This study was the application of data-driven [...] Read more.
Purpose: Cardiovascular disease (CVD) is a major worldwide health burden. As the risk factors of CVD, hypertension, and hyperlipidemia are most mentioned. Early stage hypertension in the population with dyslipidemia is an important public health hazard. This study was the application of data-driven machine learning (ML), demonstrating complex relationships between risk factors and outcomes and promising predictive performance with vast amounts of medical data, aimed to investigate the association between dyslipidemia and the incidence of early stage hypertension in a large cohort with normal blood pressure at baseline. Methods: This study analyzed annual health screening data for 71,108 people from 2005 to 2017, including data for 27 risk-related indicators, sourced from the MJ Group, a major health screening center in Taiwan. We used five machine learning (ML) methods—stochastic gradient boosting (SGB), multivariate adaptive regression splines (MARS), least absolute shrinkage and selection operator regression (Lasso), ridge regression (Ridge), and gradient boosting with categorical features support (CatBoost)—to develop a multi-stage ML algorithm-based prediction scheme and then evaluate important risk factors at the early stage of hypertension, especially for groups with high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) levels within or out of the reference range. Results: Age, body mass index, waist circumference, waist-to-hip ratio, fasting plasma glucose, and C-reactive protein (CRP) were associated with hypertension. The hemoglobin level was also a positive contributor to blood pressure elevation and it appeared among the top three important risk factors in all LDL-C/HDL-C groups; therefore, these variables may be important in affecting blood pressure in the early stage of hypertension. A residual contribution to blood pressure elevation was found in groups with increased LDL-C. This suggests that LDL-C levels are associated with CPR levels, and that the LDL-C level may be an important factor for predicting the development of hypertension. Conclusion: The five prediction models provided similar classifications of risk factors. The results of this study show that an increase in LDL-C is more important than the start of a drop in HDL-C in health screening of sub-healthy adults. The findings of this study should be of value to health awareness raising about hypertension and further discussion and follow-up research. Full article
(This article belongs to the Special Issue Intelligent Data Analysis for Medical Diagnosis)
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<p>The enrollment flowchart for subject identification.</p>
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<p>Proposed multi-stage machine learning algorithm-based scheme.</p>
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<p>ROC curves of the five algorithms for each subgroup.</p>
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<p>The variable importance generated by the generated by the five algorithms for each risk factor in the four subgroups.</p>
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19 pages, 11717 KiB  
Article
Sparse Damage Detection with Complex Group Lasso and Adaptive Complex Group Lasso
by Vasileios Dimopoulos, Wim Desmet and Elke Deckers
Sensors 2022, 22(8), 2978; https://doi.org/10.3390/s22082978 - 13 Apr 2022
Cited by 5 | Viewed by 2309
Abstract
Sparsity-based methods have recently come to the foreground of damage detection applications posing a robust and efficient alternative for traditional approaches. At the same time, low-frequency inspection is known to enable global monitoring with waves propagating over large distances. In this paper, a [...] Read more.
Sparsity-based methods have recently come to the foreground of damage detection applications posing a robust and efficient alternative for traditional approaches. At the same time, low-frequency inspection is known to enable global monitoring with waves propagating over large distances. In this paper, a single sensor complex Group Lasso methodology for the problem of structural defect localization by means of compressive sensing and complex low-frequency response functions is presented. The complex Group Lasso methodology is evaluated on composite plates with induced scatterers. An adaptive setting of the methodology is also proposed to further enhance resolution. Results from both approaches are compared with a full-array, super-resolution MUSIC technique of the same signal model. Both algorithms are shown to demonstrate high and competitive performance. Full article
(This article belongs to the Section Fault Diagnosis & Sensors)
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<p>Flowchart of the Adaptive Complex Group Lasso for Damage Detection.</p>
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<p>Experimental setup. (<b>a</b>) The composite plate with the selected imaging points and damage configurations <math display="inline"><semantics> <msub> <mi>M</mi> <mn>1</mn> </msub> </semantics></math>: 1 point-like mass, <math display="inline"><semantics> <msub> <mi>M</mi> <mn>4</mn> </msub> </semantics></math>: 4 point-like masses, <math display="inline"><semantics> <msub> <mi>M</mi> <mi>E</mi> </msub> </semantics></math>: 1 extended mass. (<b>b</b>) The implementation of a point-like mass. (<b>c</b>) The implementation of the extended mass.</p>
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<p>Damage Detection with Complex Group Lasso. (<b>a</b>) <math display="inline"><semantics> <msub> <mi>M</mi> <mn>1</mn> </msub> </semantics></math>: 1 point-like mass. (<b>b</b>) <math display="inline"><semantics> <msub> <mi>M</mi> <mn>4</mn> </msub> </semantics></math>: 4 point-like masses. (<b>c</b>) <math display="inline"><semantics> <msub> <mi>M</mi> <mi>E</mi> </msub> </semantics></math>: 1 extended mass.</p>
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<p>Damage Detection with Adaptive Complex Group Lasso. (<b>a</b>) <math display="inline"><semantics> <msub> <mi>M</mi> <mn>1</mn> </msub> </semantics></math>: 1 point-like mass. (<b>b</b>) <math display="inline"><semantics> <msub> <mi>M</mi> <mn>4</mn> </msub> </semantics></math>: 4 point-like masses. (<b>c</b>) <math display="inline"><semantics> <msub> <mi>M</mi> <mi>E</mi> </msub> </semantics></math>: 1 extended mass.</p>
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<p>Peak-to-Average Ratio with Complex Group Lasso and Adaptive Complex Group Lasso for the three damage configurations.</p>
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<p>Damage Detection with Single Sensor MUSIC. (<b>a</b>) <math display="inline"><semantics> <msub> <mi>M</mi> <mn>1</mn> </msub> </semantics></math>: 1 point-like mass. (<b>b</b>) <math display="inline"><semantics> <msub> <mi>M</mi> <mn>4</mn> </msub> </semantics></math>: 4 point-like masses. (<b>c</b>) <math display="inline"><semantics> <msub> <mi>M</mi> <mi>E</mi> </msub> </semantics></math>: 1 extended mass.</p>
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<p>Damage Detection with Full Array MUSIC. (<b>a</b>) <math display="inline"><semantics> <msub> <mi>M</mi> <mn>1</mn> </msub> </semantics></math>: 1 point-like mass. (<b>b</b>) <math display="inline"><semantics> <msub> <mi>M</mi> <mn>4</mn> </msub> </semantics></math>: 4 point-like masses. (<b>c</b>) <math display="inline"><semantics> <msub> <mi>M</mi> <mi>E</mi> </msub> </semantics></math>: 1 extended mass.</p>
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<p>Peak-to-Average Ratio with Complex Group Lasso, Adaptive Complex Group Lasso and full-array MUSIC for the three damage configurations.</p>
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<p>Noise-polluted FRFs for damage configuration <math display="inline"><semantics> <msub> <mi>M</mi> <mn>1</mn> </msub> </semantics></math> and excitation <math display="inline"><semantics> <msub> <mi>E</mi> <mn>1</mn> </msub> </semantics></math>. (<b>a</b>) SNR: 40 db. (<b>b</b>) SNR: 30 db. (<b>c</b>) SNR: 20 db. (<b>d</b>) SNR: 10 db.</p>
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<p>Peak-to-Average Ratio for damage configuration <math display="inline"><semantics> <msub> <mi>M</mi> <mn>1</mn> </msub> </semantics></math> with varying SNR. (<b>a</b>) Complex Group Lasso. (<b>b</b>) Adaptive Complex Group Lasso.</p>
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<p>Peak-to-Average Ratio for damage configuration <math display="inline"><semantics> <msub> <mi>M</mi> <mn>4</mn> </msub> </semantics></math> with varying SNR. (<b>a</b>) Complex Group Lasso. (<b>b</b>) Adaptive Complex Group Lasso.</p>
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<p>Peak-to-Average Ratio for damage configuration <math display="inline"><semantics> <msub> <mi>M</mi> <mi>E</mi> </msub> </semantics></math> with varying SNR. (<b>a</b>) Complex Group Lasso. (<b>b</b>) Adaptive Complex Group Lasso.</p>
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<p>Damage Detection for <math display="inline"><semantics> <msub> <mi>M</mi> <mn>1</mn> </msub> </semantics></math>: 1 point-like mass and SNR of 15 db. (<b>a</b>) Complex Group Lasso. (<b>b</b>) Adaptive Complex Group Lasso.</p>
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20 pages, 1753 KiB  
Article
The Classification of Profiles of Financial Catastrophe Caused by Out-of-Pocket Payments: A Methodological Approach
by Maria-Carmen García-Centeno, Román Mínguez-Salido and Raúl del Pozo-Rubio
Mathematics 2021, 9(11), 1170; https://doi.org/10.3390/math9111170 - 22 May 2021
Cited by 1 | Viewed by 2433
Abstract
The financial catastrophe resulting from the out-of-pocket payments necessary to access and use healthcare systems has been widely studied in the literature. The aim of this work is to predict the impact of the financial catastrophe a household will face as a result [...] Read more.
The financial catastrophe resulting from the out-of-pocket payments necessary to access and use healthcare systems has been widely studied in the literature. The aim of this work is to predict the impact of the financial catastrophe a household will face as a result of out-of-pocket payments in long-term care in Spain. These predictions were made using machine learning techniques such as LASSO (Least Absolute Shrinkage and Selection Operator) penalized regression and elastic-net, as well as algorithms like k-nearest neighbors (KNN), MARS (Multivariate Adaptive Regression Splines), random forest, boosted trees and SVM (Support Vector Machine). The results reveal that all the classification methods performed well, with the complex models performing better than the simpler ones and showing no evidence of overfitting. Detecting and defining the profiles of individuals and families most likely to suffer from financial catastrophe is crucial in enabling the design of financial policies aimed at protecting vulnerable groups. Full article
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<p>General outline of the process.</p>
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<p>Frequencies of the catastrophic rate in the training and test groups.</p>
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<p>Tuning process. The y-axis measures the accuracy (percentage of correct classifications) and the x-axis measures the tuning parameters of the corresponding algorithm.</p>
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<p>Tuning process. The y-axis measures the accuracy (percentage of correct classifications) and the x-axis measures the tuning parameters of the corresponding algorithm.</p>
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