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18 pages, 11145 KiB  
Article
Improving Hydrological Simulations with a Dynamic Vegetation Parameter Framework
by Haiting Gu, Yutai Ke, Zhixu Bai, Di Ma, Qianwen Wu, Jiongwei Sun and Wanghua Yang
Water 2024, 16(22), 3335; https://doi.org/10.3390/w16223335 (registering DOI) - 20 Nov 2024
Viewed by 89
Abstract
Many hydrological models incorporate vegetation-related parameters to describe hydrological processes more precisely. These parameters should adjust dynamically in response to seasonal changes in vegetation. However, due to limited information or methodological constraints, vegetation-related parameters in hydrological models are often treated as fixed values, [...] Read more.
Many hydrological models incorporate vegetation-related parameters to describe hydrological processes more precisely. These parameters should adjust dynamically in response to seasonal changes in vegetation. However, due to limited information or methodological constraints, vegetation-related parameters in hydrological models are often treated as fixed values, which restricts model performance and hinders the accurate representation of hydrological responses to vegetation changes. To address this issue, a vegetation-related dynamic-parameter framework is applied on the Xinanjiang (XAJ) model, which is noted as Eco-XAJ. The dynamic-parameter framework establishes the regression between the Normalized Difference Vegetation Index (NDVI) and the evapotranspiration parameter K. Two routing methods are used in the models, i.e., the unit hydrograph (XAJ-UH and Eco-XAJ-UH) and the Linear Reservoir (XAJ-LR and Eco-XAJ-LR). The original XAJ model and the modified Eco-XAJ model are applied to the Ou River Basin, with detailed comparisons and analyses conducted under various scenarios. The results indicate that the Eco-XAJ model outperforms the original model in long-term discharge simulations, with the NSE increasing from 0.635 of XAJ-UH to 0.647 of Eco-XAJ-UH. The Eco-XAJ model also reduces overestimation and incorrect peak flow simulations during dry seasons, especially in the year 1991. In drought events, the modified model significantly enhances water balance performance. The Eco-XAJ-UH outperforms the XAJ-UH in 9 out of 16 drought events, while the Eco-XAJ-LR outperforms the XAJ-LR in 14 out of 16 drought events. The results demonstrate that the dynamic-parameter model, in regard to vegetation changes, offers more accurate simulations of hydrological processes across different scenarios, and its parameters have reasonable physical interpretations. Full article
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Figure 1

Figure 1
<p>Location and basic information for the Ou River basin.</p>
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<p>Flowchart of the study.</p>
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<p>Procedure of building the Eco-XAJ model.</p>
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<p>Scatter plot of K and the NDVI: (<b>a</b>,<b>b</b>) represent the XAJ-UH model and (<b>c</b>,<b>d</b>) represent the XAJ-LR model. <math display="inline"><semantics> <mrow> <msub> <mrow> <mi mathvariant="normal">N</mi> <mi mathvariant="normal">D</mi> <mi mathvariant="normal">V</mi> <mi mathvariant="normal">I</mi> </mrow> <mrow> <mi mathvariant="normal">t</mi> </mrow> </msub> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <msub> <mrow> <mi mathvariant="normal">K</mi> </mrow> <mrow> <mi mathvariant="normal">t</mi> </mrow> </msub> </mrow> </semantics></math> indicate the relationship for the same month; <math display="inline"><semantics> <mrow> <msub> <mrow> <mi mathvariant="normal">N</mi> <mi mathvariant="normal">D</mi> <mi mathvariant="normal">V</mi> <mi mathvariant="normal">I</mi> </mrow> <mrow> <mi mathvariant="normal">t</mi> <mo>−</mo> <mn>1</mn> </mrow> </msub> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <msub> <mrow> <mi mathvariant="normal">K</mi> </mrow> <mrow> <mi mathvariant="normal">t</mi> </mrow> </msub> </mrow> </semantics></math> indicate the relationship with a one-month lag.</p>
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<p>Hydrograph of the Eco-XAJ-UH model in (<b>a</b>) the full period, (<b>b</b>) Duration I (the wet season), (<b>c</b>) Duration II (the dry season), and (<b>d</b>) Duration III (the recession periods).</p>
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<p>Hydrograph of the Eco-XAJ-LR model in (<b>a</b>) the full period, (<b>b</b>) Duration I (the wet season), (<b>c</b>) Duration II (the dry season), and (<b>d</b>) Duration III (the recession periods).</p>
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<p>Comparison of the simulation (<b>a</b>,<b>b</b>) between the XAJ-UH model and the Eco-XAJ-UH model, and (<b>c</b>,<b>d</b>) between the XAJ-LR model and the Eco-XAJ-LR model.</p>
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<p>(<b>a</b>,<b>c</b>) are scatter plots of corresponding discharge errors, while (<b>b</b>,<b>d</b>) show scatter plots and the cumulative ∆Error when the observed discharge is below 1000 m<sup>3</sup>/s, where <math display="inline"><semantics> <mrow> <mo>∆</mo> <mi mathvariant="normal">E</mi> <mi mathvariant="normal">r</mi> <mi mathvariant="normal">r</mi> <mi mathvariant="normal">o</mi> <mi mathvariant="normal">r</mi> <mo>=</mo> <mo stretchy="false">|</mo> <msub> <mrow> <mi mathvariant="normal">E</mi> <mi mathvariant="normal">r</mi> <mi mathvariant="normal">r</mi> <mi mathvariant="normal">o</mi> <mi mathvariant="normal">r</mi> </mrow> <mrow> <mi mathvariant="normal">X</mi> <mi mathvariant="normal">A</mi> <mi mathvariant="normal">J</mi> </mrow> </msub> <mo stretchy="false">|</mo> <mo>−</mo> <mo stretchy="false">|</mo> <msub> <mrow> <mi mathvariant="normal">E</mi> <mi mathvariant="normal">r</mi> <mi mathvariant="normal">r</mi> <mi mathvariant="normal">o</mi> <mi mathvariant="normal">r</mi> </mrow> <mrow> <mi mathvariant="normal">E</mi> <mi mathvariant="normal">c</mi> <mi mathvariant="normal">o</mi> <mo>−</mo> <mi mathvariant="normal">X</mi> <mi mathvariant="normal">A</mi> <mi mathvariant="normal">J</mi> </mrow> </msub> <mo stretchy="false">|</mo> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <mover accent="true"> <mrow> <mo>∆</mo> <mi mathvariant="normal">E</mi> <mi mathvariant="normal">r</mi> <mi mathvariant="normal">r</mi> <mi mathvariant="normal">o</mi> <mi mathvariant="normal">r</mi> </mrow> <mo>¯</mo> </mover> </mrow> </semantics></math> is the mean value of <math display="inline"><semantics> <mrow> <mo>∆</mo> <mi mathvariant="normal">E</mi> <mi mathvariant="normal">r</mi> <mi mathvariant="normal">r</mi> <mi mathvariant="normal">o</mi> <mi mathvariant="normal">r</mi> </mrow> </semantics></math>.</p>
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<p>Hydrograph of Eco-XAJ-UH and the original model during the dry seasons of (<b>a</b>) 1990, (<b>b</b>) 1991, (<b>c</b>) 1992, (<b>d</b>) 1993, and (<b>e</b>) 1994.</p>
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<p>Hydrograph of Eco-XAJ-LR and the original model during the dry seasons of (<b>a</b>) 1990, (<b>b</b>) 1991, (<b>c</b>) 1992, (<b>d</b>) 1993, and (<b>e</b>) 1994.</p>
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<p>(<b>a</b>,<b>c</b>) Comparison the <math display="inline"><semantics> <mrow> <mi>p</mi> <mi>B</mi> <mi>I</mi> <mi>A</mi> <mi>S</mi> </mrow> </semantics></math> of the Eco-XAJ models and the XAJ models during low-flow periods. (<b>b</b>,<b>d</b>) <math display="inline"><semantics> <mrow> <mo>∆</mo> <mi>p</mi> <mi>B</mi> <mi>I</mi> <mi>A</mi> <mi>S</mi> </mrow> </semantics></math> of the Eco-XAJ models and the XAJ models during low-flow periods, where <math display="inline"><semantics> <mrow> <mo>∆</mo> <mi>p</mi> <mi>B</mi> <mi>I</mi> <mi>A</mi> <mi>S</mi> <mo>=</mo> <msub> <mrow> <mo>|</mo> <mi>p</mi> <mi>B</mi> <mi>I</mi> <mi>A</mi> <mi>S</mi> </mrow> <mrow> <mi mathvariant="normal">X</mi> <mi mathvariant="normal">A</mi> <mi mathvariant="normal">J</mi> </mrow> </msub> <mo stretchy="false">|</mo> <mo>−</mo> <msub> <mrow> <mo>|</mo> <mi>p</mi> <mi>B</mi> <mi>I</mi> <mi>A</mi> <mi>S</mi> </mrow> <mrow> <mi mathvariant="normal">E</mi> <mi mathvariant="normal">c</mi> <mi mathvariant="normal">o</mi> <mo>−</mo> <mi mathvariant="normal">X</mi> <mi mathvariant="normal">A</mi> <mi mathvariant="normal">J</mi> </mrow> </msub> <mo stretchy="false">|</mo> </mrow> </semantics></math>.</p>
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14 pages, 1196 KiB  
Article
Green Energy, Economic Growth, and Innovation for Sustainable Development in OECD Countries
by Tianhao Zhao and Syed Ahsan Ali Shah
Sustainability 2024, 16(22), 10113; https://doi.org/10.3390/su162210113 (registering DOI) - 20 Nov 2024
Viewed by 116
Abstract
This study explores the interrelationship between green energy adoption, economic growth, and innovation in promoting sustainable development within OECD countries. Using a random forest regression model, the research analyzes secondary data from 2013 to 2022 to identify the most significant contributors to sustainable [...] Read more.
This study explores the interrelationship between green energy adoption, economic growth, and innovation in promoting sustainable development within OECD countries. Using a random forest regression model, the research analyzes secondary data from 2013 to 2022 to identify the most significant contributors to sustainable development. The random forest model was selected for its ability to handle non-linear relationships and feature importance ranking, providing a comprehensive understanding of the variables’ impacts. The analysis reveals that green energy adoption has the strongest influence on the human development index (HDI), with an importance score of 0.43, followed by gross domestic product (GDP) and the global innovation index (GII). These findings underscore the pivotal role of green energy adoption, amplified by economic growth and technological innovation, in advancing sustainable development. While the study focuses on OECD countries, the insights offer valuable implications for global sustainability initiatives. The evidence supports the argument that prioritizing green energy, supported by economic and innovative drivers, is crucial for achieving broader sustainable development goals. This research provides a methodological contribution by demonstrating the effectiveness of machine learning models in analyzing complex sustainability data and offers empirical evidence that informs policy and future research in a broader context. Full article
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Figure 1
<p>Boxplots of GEA, GDP, GII, and HDI (2013–2022).</p>
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<p>Trend of GEA, GDP, GII, and HDI (2013–2022).</p>
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<p>Scatter plots depicting the relationships between GEA and HDI (Plot 1), GDP and HDI (Plot 2), and GII and HDI (Plot 3).</p>
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<p>(<b>a</b>) Out-of-bag error rate, (<b>b</b>) learning curve, (<b>c</b>) predicted vs. actual values, and (<b>d</b>) partial dependence plots.</p>
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21 pages, 2163 KiB  
Article
Research on Check-In Baggage Flow Prediction for Airport Departure Passengers Based on Improved PSO-BP Neural Network Combination Model
by Bo Jiang, Jian Zhang, Jianlin Fu, Guofu Ding and Yong Zhang
Aerospace 2024, 11(11), 953; https://doi.org/10.3390/aerospace11110953 (registering DOI) - 20 Nov 2024
Viewed by 97
Abstract
Accurate forecasting of passenger checked baggage traffic is crucial for efficient and intelligent allocation and optimization of airport service resources. A systematic analysis of the influencing factors and prediction algorithms for the baggage flow is rarely included in existing studies. To accurately capture [...] Read more.
Accurate forecasting of passenger checked baggage traffic is crucial for efficient and intelligent allocation and optimization of airport service resources. A systematic analysis of the influencing factors and prediction algorithms for the baggage flow is rarely included in existing studies. To accurately capture the trend of baggage flow, a combined PCC-PCA-PSO-BP baggage flow prediction model is proposed. This study applies the model to predict the departing passengers’ checked baggage flow at Chengdu Shuangliu International Airport in China. First, in the preprocessing of the data, multiple interpolation demonstrates a better numerical interpolation effect compared to mean interpolation, regression interpolation, and expectation maximization (EM) interpolation in cases of missing data. Second, in terms of the influencing factors, unlike factors that affect the airport passenger flow, the total retail sales of consumer goods have a weak relationship with the baggage flow. The departure passenger flow and flight takeoff and landing sorties play a dominant role in the baggage flow. The railway passenger flow, highway passenger flow, and months have statistically significant effects on the changes in the baggage flow. Factors such as holidays and weekends also contribute to the baggage flow alternation. Finally, the PCC-PCA-PSO-BP model is proposed for predicting the baggage flow. This model exhibits superior performance in terms of the network convergence speed and prediction accuracy compared to four other models: BP, PCA-BP, PSO-BP, and PCA-PSO-BP. This study provides a novel approach for predicting the flow of checked baggage for airport departure passengers. Full article
(This article belongs to the Section Air Traffic and Transportation)
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Figure 1

Figure 1
<p>The baggage handling process at the airport.</p>
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<p>Compares the departure passenger flow and baggage flow of Chengdu Shuangliu International Airport during different months of 2018.</p>
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<p>Flow chart of the PCC-PCA-PSO-BP prediction model.</p>
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<p>Structure of the BP neural network (a 7-3-1 structured BP neural network serves as an illustrative example).</p>
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<p>After numerical interpolation of the original dataset, the departure passenger flow (<b>a</b>), flight takeoff and landing frequency (<b>b</b>), baggage flow (<b>c</b>), TRSCG (<b>d</b>), non-working days (<b>e</b>), railway passenger flow (<b>f</b>) and highway passenger flow (<b>g</b>) were organized over time.</p>
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<p>A PCA scree plot.</p>
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<p>Convergence characteristics of the different models: (<b>a</b>) PCC-PCA-PSO-BP model, (<b>b</b>) PCA-PSO-BP model, (<b>c</b>) PCA-BP model, (<b>d</b>) PSO-BP model, and (<b>e</b>) BP model.</p>
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23 pages, 17355 KiB  
Article
Development of a Machine Learning Natural Ventilation Rate Model by Studying the Wind Field Inside and Around Multiple-Row Chinese Solar Greenhouses
by Ran Liu, Yunyan Shi, Pierre-Emmanuel Bournet and Kaige Liu
Horticulturae 2024, 10(11), 1226; https://doi.org/10.3390/horticulturae10111226 (registering DOI) - 20 Nov 2024
Viewed by 172
Abstract
This paper experimented with a methodology of machine learning modelling using virtual samples generated by fast CFD (Computational Fluid Dynamics) simulations in order to predict the greenhouse natural ventilation. However, the output natural ventilation rates using fast two-dimensional (2D) CFD models are not [...] Read more.
This paper experimented with a methodology of machine learning modelling using virtual samples generated by fast CFD (Computational Fluid Dynamics) simulations in order to predict the greenhouse natural ventilation. However, the output natural ventilation rates using fast two-dimensional (2D) CFD models are not always consistent with the three-dimensional (3D) one for all the scenarios. The first contribution of this paper is a proposed comparative modelling methodology between two-dimensional and three-dimensional CFD studies, regarding its validity, especially when buildings are in rows. The results show that the error of the ventilation rate prediction could exceed 50%, if 2D models are not properly used. Subsequently, in those scenarios where the 2D and the 3D models had equal accuracy, nearly one thousand samples were generated using fast 2D CFD simulations to train a natural ventilation rate regression tree model. This model is efficient to deal with the combined effect of wind pressure and thermal gradients under various vent configurations, with only four necessary inputs. In addition, by analyzing the wind speed distribution contour of the outdoor wind field around the greenhouse rows, the optimal wind speed-measuring locations were determined to eliminate interference for predicting the natural ventilation rate. Full article
(This article belongs to the Special Issue Cultivation and Production of Greenhouse Horticulture)
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Figure 1
<p>Chinese solar greenhouse rows, Beijing.</p>
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<p>Structure of the experimental greenhouse.</p>
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<p>Mesh of the windward and leeward flow fields and greenhouses A, B, C. The difference between the windward and leeward meshes is in the length computational domains in front and behind the greenhouse.</p>
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<p>Process of creating a mesh file: (<b>a</b>) is the process of creating Ogrid Block; (<b>b</b>) is the result of the roof boundary layer block; and (<b>c</b>) is the final global block split result.</p>
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<p>Wall y<sup>+</sup> value for the case where the first cell height is 0.025 m.</p>
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<p>Monitoring location (red lines) of wind speed: (<b>a</b>) for windward flow and (<b>b</b>) for leeward flow.</p>
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<p>Comparison of the predicted ventilation rate between the regression trees and theoretical models.</p>
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<p>Ratio error of the ventilation rate between the 2D and 3D cases under windward and leeward conditions. Ventilation rate from the 2D and 3D cases for each greenhouse. G A, G B, and G C are, respectively, greenhouses A, B, and C. See <a href="#horticulturae-10-01226-f003" class="html-fig">Figure 3</a> for the positions of greenhouses A, B, and C. A negative value means that the lower vent is a net outflow.</p>
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<p>Velocity vectors of the windward flow when <span class="html-italic">u</span><sub>2.5</sub> is 3 m s<sup>−1</sup>: (<b>a</b>) from the 2D simulation and (<b>b</b>) at the same location from the 3D simulation; (<b>c</b>) top view at lower vents height from the 3D simulation.</p>
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<p>Streamlines of the windward flow when <span class="html-italic">u</span><sub>2.5</sub> is 3 m s<sup>−1</sup>. (<b>a</b>–<b>c</b>) are for greenhouses A, B, and C, where streamlines start from the lower vents. (<b>d</b>) is for greenhouse B, where streamlines start from the upper vents.</p>
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<p>Streamlines of the windward flow when <span class="html-italic">u</span><sub>2.5</sub> is 1 m s<sup>−1</sup> and temperature contour for greenhouse B.</p>
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<p>Velocity vectors of the leeward flow when u<sub>2.5</sub> is 3 m s<sup>−1</sup>. (<b>a</b>) is from the 2D simulation and (<b>b</b>) is the same location from the 3D simulation. (<b>c</b>) is the overhead view at lower vents height from the 3D simulation.</p>
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<p>Wind speed at the monitoring location. (<b>a</b>,<b>c</b>) are under the windward flow, and (<b>b</b>,<b>d</b>) are under the leeward flow. (<b>a</b>,<b>b</b>) are located perpendicular to the wind direction at 2.5 m height in the middle E-W cross-section of the greenhouse. (<b>c</b>,<b>d</b>) are located parallel to the wind direction at 2.5 m height in the middle N-S cross-section. The gray area is the recommended area to place wind speed sensors. <span class="html-fig-inline" id="horticulturae-10-01226-i001"><img alt="Horticulturae 10 01226 i001" src="/horticulturae/horticulturae-10-01226/article_deploy/html/images/horticulturae-10-01226-i001.png"/></span> is the wind direction.</p>
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<p>Contour of the wind speed on the 2.5 m height horizontal plane. (<b>a</b>) is the windward flow and (<b>b</b>) is the leeward flow.</p>
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<p>Responses of the regression tree ventilation model: predicted vs. actual plot.</p>
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<p>Comparison of the predicted ventilation rate between the regression tree and theoretical models: (<b>a</b>) is the outputs and (<b>b</b>) is the inputs. Wind speeds are in the range of 1–5 m s<sup>−1</sup> (purple line); temperature differences are in the range of 0–10 K (red line); equal vent-opening areas for the upper and lower vents were 10, 20, and 30 m<sup>2</sup> (green line); 0 represents the windward direction and 1 represents the leeward direction (orange line). The β value of the theoretical model is 0.5 under windward flow and 0.2 under leeward flow for Equation (10).</p>
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<p>Application of the regression tree model.</p>
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<p>Dataset used for the model validation with the temperature and humidity on 20–26 September 2019. <span class="html-italic">T</span> is the averaged indoor temperature, K; <span class="html-italic">T<sub>o</sub></span> is the outdoor temperature, K; <span class="html-italic">h</span> is the averaged indoor absolute humidity, kg kg<sup>−1</sup>; <span class="html-italic">h<sub>o</sub></span> is the outdoor absolute humidity, kg kg<sup>−1</sup>; <span class="html-italic">RH</span> is the averaged indoor relative humidity, %; and <span class="html-italic">RH<sub>o</sub></span> is the outdoor relative humidity, %.</p>
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17 pages, 319 KiB  
Article
Cardiovascular Diseases and Metabolic Medications in the Lebanese Population: A Post Hoc Analysis from a Nationwide Cross-Sectional Study
by Rony M. Zeenny, Rachel Abdo, Chadia Haddad, Aline Hajj, Rouba Karen Zeidan, Pascale Salameh and Jean Ferrieres
Pharmacy 2024, 12(6), 171; https://doi.org/10.3390/pharmacy12060171 (registering DOI) - 20 Nov 2024
Viewed by 144
Abstract
Objective: This study assesses the association of metabolic drugs (specifically hypoglycemic and hypolipemic agents) with cardiovascular diseases (CVD) among the Lebanese population and patients’ subgroups. Methods: A nationwide cross-sectional retrospective study was carried out in Lebanon. The survey collected information on sociodemographic characteristics, [...] Read more.
Objective: This study assesses the association of metabolic drugs (specifically hypoglycemic and hypolipemic agents) with cardiovascular diseases (CVD) among the Lebanese population and patients’ subgroups. Methods: A nationwide cross-sectional retrospective study was carried out in Lebanon. The survey collected information on sociodemographic characteristics, lifestyles, comorbidities, and medication use. Logistic regression models were employed to analyze the data and determine associations between CVD and metabolic drugs. Stratification analyses were performed based on diabetes and dyslipidemia status. Results: The study found significant associations with CVD among the 2048 participants. Higher scores on the Lebanese Mediterranean Diet Score (LMDS; ORa = 1.06), hypertension (ORa = 1.71), diabetes (ORa = 1.75), dyslipidemia (ORa = 1.89), family history of CVD (ORa = 1.58), and smoking (previous: ORa = 1.63, current: ORa = 2.15) were linked to increased CVD odds. Higher income (intermediate: ORa = 0.64, high: ORa = 0.40) was inversely related to it. A subsequent model that included hypoglycemic and lipid-lowering medications yielded similar results. However, neither hypoglycemic nor lipid-lowering medications demonstrated a significant association with CVD risk. A third regression model was conducted by taking the classes of drugs as an independent variable. Also, the result revealed that all the classes of medication were not associated with the risk of CVD. Stratification by diabetes revealed LMDS and hypertension as risk factors in both groups. Among non-diabetic participants, dyslipidemia (ORa = 2.40), current smoking (ORa = 2.28), and higher income (intermediate: ORa = 0.57, high: ORa = 0.62) were linked to CVD. Among people with diabetes, a family history of CVD (ORa = 2.69) increased the CVD odds, while being an employer (ORa = 0.49) lowered it. Stratification by dyslipidemia showed consistent risk factors, and higher LMDS (ORa = 1.07), diabetes (ORa = 2.14), hypertension (ORa = 1.79), and previous smoking (ORa = 1.95) were linked to CVD without dyslipidemia. Being a female (ORa = 0.52) and having a lower income (ORa = 0.40) were associated with lower CVD odds in those with dyslipidemia. Subgroup analyses showed that medications were not significantly associated with CVD odds among patients with diabetes or hyperlipidemia. Conclusions: This study’s findings highlight the importance of addressing modifiable risk factors and socioeconomic factors to reduce the burden of CVD. Targeted interventions and longitudinal research are necessary to optimize preventive strategies and improve the management of CVD in individuals using hypoglycemic and hypolipemic agents in low- and medium-income countries. Full article
16 pages, 498 KiB  
Article
Sociocultural and Clinical Determinants of Sexual Dysfunction in Perimenopausal Women with and Without Breast Cancer
by Osiris G. Delgado-Enciso, Valery Melnikov, Gustavo A. Hernandez-Fuentes, Jessica C. Romero-Michel, Daniel A. Montes-Galindo, Veronica M. Guzmán-Sandoval, Josuel Delgado-Enciso, Mario Ramirez-Flores, Iram P. Rodriguez-Sanchez, Margarita L. Martinez-Fierro, Idalia Garza-Veloz, Karmina Sánchez-Meza, Carmen A. Sanchez-Ramirez, Carmen Meza-Robles and Ivan Delgado-Enciso
Curr. Oncol. 2024, 31(11), 7363-7378; https://doi.org/10.3390/curroncol31110543 (registering DOI) - 20 Nov 2024
Viewed by 102
Abstract
Breast cancer survivorship is a recognized risk factor for sexual dysfunction, with various clinical, sociocultural, and psychological factors potentially interacting differently across populations. This study compared sexual dysfunction, anxiety, and depression between females with breast cancer and those without, aiming to identify associated [...] Read more.
Breast cancer survivorship is a recognized risk factor for sexual dysfunction, with various clinical, sociocultural, and psychological factors potentially interacting differently across populations. This study compared sexual dysfunction, anxiety, and depression between females with breast cancer and those without, aiming to identify associated factors. A total of 362 females participated, including 227 with sexual dysfunction and 135 controls. Among them, 195 are breast cancer survivors, while 167 have no personal history of cancer. Key variables were analyzed using Student’s t-test for quantitative data and Fisher’s exact test for categorical data, while logistic regression models were used to assess the association between sexual dysfunction and various factors. Multivariate analysis revealed that, in sexually active females, breast cancer survivorship increased the odds of sexual dysfunction 2.7-fold (95% CI: 1.17–6.49; p = 0.020). Anxiety was significantly associated with sexual dysfunction, regardless of cancer status (AdOR 6.00; 95% CI: 2.50–14.43; p < 0.001). The interaction between cancer survival and anxiety further increased the odds of sexual dysfunction by more than 11-fold (AdOR 11.55; 95% CI: 3.81–35.04; p < 0.001). Additionally, obesity was found to be a protective factor among cancer survivors (AdOR 0.149; 95% CI: 0.027–0.819; p = 0.029). In conclusion, breast cancer has a significant impact on sexual function, with psychological factors like anxiety playing a crucial role. Addressing these issues requires a holistic, patient-centered approach that considers the complex interplay of physical, emotional, and sociocultural factors. Full article
(This article belongs to the Topic Life of Cancer Survivor)
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<p>Flowchart of participant screening and inclusion for breast cancer study in Western Mexico.</p>
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27 pages, 573 KiB  
Article
Machine Learning-Based Methodologies for Cyber-Attacks and Network Traffic Monitoring: A Review and Insights
by Filippo Genuario, Giuseppe Santoro, Michele Giliberti, Stefania Bello, Elvira Zazzera and Donato Impedovo
Information 2024, 15(11), 741; https://doi.org/10.3390/info15110741 (registering DOI) - 20 Nov 2024
Viewed by 132
Abstract
The number of connected IoT devices is increasing significantly due to their many benefits, including automation, improved efficiency and quality of life, and reducing waste. However, these devices have several vulnerabilities that have led to the rapid growth in the number of attacks. [...] Read more.
The number of connected IoT devices is increasing significantly due to their many benefits, including automation, improved efficiency and quality of life, and reducing waste. However, these devices have several vulnerabilities that have led to the rapid growth in the number of attacks. Therefore, several machine learning-based intrusion detection system (IDS) tools have been developed to detect intrusions and suspicious activity to and from a host (HIDS—Host IDS) or, in general, within the traffic of a network (NIDS—Network IDS). The proposed work performs a comparative analysis and an ablative study among recent machine learning-based NIDSs to develop a benchmark of the different proposed strategies. The proposed work compares both shallow learning algorithms, such as decision trees, random forests, Naïve Bayes, logistic regression, XGBoost, and support vector machines, and deep learning algorithms, such as DNNs, CNNs, and LSTM, whose approach is relatively new in the literature. Also, the ensembles are tested. The algorithms are evaluated on the KDD-99, NSL-KDD, UNSW-NB15, IoT-23, and UNB-CIC IoT 2023 datasets. The results show that the NIDS tools based on deep learning approaches achieve better performance in detecting network anomalies than shallow learning approaches, and ensembles outperform all the other models. Full article
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<p>(<b>a</b>) LSTM and (<b>b</b>) GRU units.</p>
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12 pages, 2016 KiB  
Article
Validation of Ultrasound Measurement of Vastus Lateralis for Appendicular Skeletal Muscle Mass in Chronic Kidney Disease Patients with Hemodialysis
by Peng-Ta Liu, Ta-Sen Wei and Congo Tak-Shing Ching
Diagnostics 2024, 14(22), 2600; https://doi.org/10.3390/diagnostics14222600 (registering DOI) - 20 Nov 2024
Viewed by 150
Abstract
Background: Chronic kidney disease patients undergoing hemodialysis (HD) are at a high risk of developing sarcopenia. This study aimed to validate the performance of ultrasound (US) measurements of the vastus lateralis (VL) for estimating muscle mass and diagnosing sarcopenia in CKD patients with [...] Read more.
Background: Chronic kidney disease patients undergoing hemodialysis (HD) are at a high risk of developing sarcopenia. This study aimed to validate the performance of ultrasound (US) measurements of the vastus lateralis (VL) for estimating muscle mass and diagnosing sarcopenia in CKD patients with HD. Methods: Forty-six patients were enrolled in this study. Muscle thickness (MT) and echo intensity (EI) of VL, physical performance, and biochemical markers were collected to establish a linear regression model for predicting appendicular skeletal muscle mass (ASM), using dual-energy X-ray absorptiometry (DXA) as the reference standard. The model’s performance was validated, and its diagnostic accuracy for sarcopenia was also evaluated. Results: An ASM prediction model was derived: −20.17 + 1.90 × MT_VL (cm) + 1.58 × male + 0.16 × Height (cm) + 0.09 × Weight (kg) + 0.05 × Age (year), with a standard estimated error of 1.44 kg and adjusted R-squared of 0.84. The model exhibited high correlation and an acceptable limit of agreement, compared to DXA measurement. EI displayed a negative correlation with ASM and MT. Conclusions: The ASM adjusted with BMI demonstrated superior performance in diagnosing sarcopenia compared to the ASM adjusted with height. Ultrasound provides a cost-effective bedside tool for evaluating muscle conditions in HD patients. Full article
(This article belongs to the Special Issue Diagnosis and Treatment of Kidney Disease)
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<p>Ultrasound measurement and transducer placement on the vastus lateralis. The muscle thickness of the vastus lateralis was depicted by the green dotted line, while the echo intensity was obtained from the yellow region of interest.</p>
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<p>(<b>a</b>) Correlation between muscle mass obtained by DXA-measured and US-derived methods. (<b>b</b>) Bland–Altman plot comparing muscle mass measurements obtained from DXA and US at the vastus lateralis. The red line represents mean difference. CCC: concordance correlation coefficient, DXA: dual-energy X-ray absorptiometry, US: ultrasound.</p>
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<p>Comparison of receiver operating characteristic (ROC) with area under curve (AUC) among four sarcopenia consensuses.</p>
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<p>The correlation heatmap between demographic data, biochemical tests, ultrasound muscle parameters, and physical performances. Alb: albumin, ASM: appendicular skeletal muscle mass by DXA, BMI: body mass index, Chol: cholesterol, Cr: creatinine, CPR: C-reactive protein, eGFR: estimated glomerular filtration rate, MT: muscle thickness, EI: echogenicity, TUG: timed up and go. *: <span class="html-italic">p</span> &lt; 0.05, **: <span class="html-italic">p</span> &lt; 0.01, ***: <span class="html-italic">p</span> &lt; 0.001.</p>
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12 pages, 2456 KiB  
Article
ICOSLG Is Associated with Anti-PD-1 and Concomitant Antihistamine Treatment Response in Advanced Melanoma
by Domenico Mallardo, Mario Fordellone, Margaret Ottaviano, Giuseppina Marano, Maria Grazia Vitale, Mario Mallardo, Mariagrazia Capasso, Teresa De Cristofaro, Mariaelena Capone, Teresa Meinardi, Miriam Paone, Patrizia Sabatelli, Rosaria De Filippi, Alessandra Cesano, Ernesta Cavalcanti, Corrado Caracò, Sarah Warren, Alfredo Budillon, Ester Simeone and Paolo Antonio Ascierto
Int. J. Mol. Sci. 2024, 25(22), 12439; https://doi.org/10.3390/ijms252212439 - 19 Nov 2024
Viewed by 221
Abstract
We previously demonstrated that patients with metastatic unresectable stage IIIb–IV melanoma receiving cetirizine (a second-generation H1 antagonist antihistamine) premedication with immunotherapy had better outcomes than those not receiving cetirizine. In this retrospective study, we searched for a gene signature potentially predictive of the [...] Read more.
We previously demonstrated that patients with metastatic unresectable stage IIIb–IV melanoma receiving cetirizine (a second-generation H1 antagonist antihistamine) premedication with immunotherapy had better outcomes than those not receiving cetirizine. In this retrospective study, we searched for a gene signature potentially predictive of the response to the addition of cetirizine to checkpoint inhibition (nivolumab or pembrolizumab with or without previous ipilimumab). Transcriptomic analysis showed that inducible T cell costimulator ligand (ICOSLG) expression directly correlated with the disease control rate (DCR) when detected with a loading value > 0.3. A multivariable logistic regression model showed a positive association between the DCR and ICOSLG expression for progression-free survival and overall survival. ICOSLG expression was associated with CD64, a specific marker of M1 macrophages, at baseline in the patient samples who received cetirizine concomitantly with checkpoint inhibitors, but this association was not present in subjects who had not received cetirizine. In conclusion, our results show that the clinical advantage of concomitant treatment with cetirizine during checkpoint inhibition in patients with malignant melanoma is associated with high ICOSLG expression, which could predict the response to immune checkpoint inhibitor blockade. Full article
(This article belongs to the Special Issue Advances in Melanoma and Skin Cancers: 2nd Edition)
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<p>Gene signature expression in responder and non-responder patients (Wilcoxon test, <span class="html-italic">p</span> = 8.3 × 10<sup>−8</sup>). The signature included 15 genes, namely <span class="html-italic">TRAF1</span>, <span class="html-italic">S100A9</span>, <span class="html-italic">S100A8</span>, <span class="html-italic">S100A12</span>, <span class="html-italic">OLR1</span>, <span class="html-italic">NF1</span>, <span class="html-italic">MMP9</span>, <span class="html-italic">LDHA</span>, <span class="html-italic">ITGAM</span>, <span class="html-italic">ICOSLG</span>, <span class="html-italic">HLA-DPA1</span>, <span class="html-italic">FSTL3</span>, <span class="html-italic">CST2</span>, <span class="html-italic">CLEC5A</span>, and <span class="html-italic">ANLN</span>.</p>
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<p>PFS according to having received or not received cetirizine in (<b>A</b>) patients with low ICOSLG expression (<span class="html-italic">n</span> = 30) and (<b>B</b>) patients with high ICOSLG expression (<span class="html-italic">N</span> = 86).</p>
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<p>PFS according to having received or not received cetirizine in (<b>A</b>) patients with low ICOSLG expression (<span class="html-italic">n</span> = 30) and (<b>B</b>) patients with high ICOSLG expression (<span class="html-italic">N</span> = 86).</p>
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<p>OS in patients treated or not treated with cetirizine and (<b>A</b>) with low ICOSLG expression (<span class="html-italic">n</span> = 30) or (<b>B</b>) with high ICOSLG expression (<span class="html-italic">N</span> = 86).</p>
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<p>OS in patients treated or not treated with cetirizine and (<b>A</b>) with low ICOSLG expression (<span class="html-italic">n</span> = 30) or (<b>B</b>) with high ICOSLG expression (<span class="html-italic">N</span> = 86).</p>
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<p>Multivariable survival analysis according to PFS (<b>A</b>) and OS (<b>B</b>) for ICOSLG expression. * <span class="html-italic">p</span> ≤ 0.05, ** <span class="html-italic">p</span> ≤ 0.01, *** <span class="html-italic">p</span> ≤ 0.001.</p>
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<p>Multivariable survival analysis according to PFS (<b>A</b>) and OS (<b>B</b>) for ICOSLG expression. * <span class="html-italic">p</span> ≤ 0.05, ** <span class="html-italic">p</span> ≤ 0.01, *** <span class="html-italic">p</span> ≤ 0.001.</p>
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18 pages, 2011 KiB  
Article
Demographic and Geographic Characteristics Associated with the Type of Prescription and Drug Expenditure: Real World Evidence for Greece During 2015–2021
by Georgios Mavridoglou and Nikolaos Polyzos
Healthcare 2024, 12(22), 2312; https://doi.org/10.3390/healthcare12222312 - 19 Nov 2024
Viewed by 368
Abstract
Aim: Electronic prescribing has allowed for the collection of prescription data in real time in Greece for the first time. Hence, the aim of the current study was to present the characteristics of prescriptions for the Greek population during the period from 2015 [...] Read more.
Aim: Electronic prescribing has allowed for the collection of prescription data in real time in Greece for the first time. Hence, the aim of the current study was to present the characteristics of prescriptions for the Greek population during the period from 2015 to 2021. Methods: This retrospective study was based on data extracted from the nationwide Greek electronic prescription database between January 2015 and December 2021. Descriptive statistics methods were used for the needs of the study. As the basic figures examined depend on the size of the population, in order for the results to be comparable, we estimated the corresponding measures per inhabitant, using population data from the Greek Statistical Authority. Appropriate indicators for the comparison of consumption and expenditure over time were estimated. A study of the trend was also carried out using time series and linear regression models. In order to facilitate the design and implementation of specialized policies, it is useful to identify the drug categories with the highest consumption and expenditure, as well as the geographical areas that present similar characteristics. For the first, ABC analysis was used, which helps to identify the most popular categories of drugs, while for the second, cluster analysis was carried out. Agglomerative clustering was used to divide the regions into similar groups. This hierarchical clustering algorithm classifies the population into several clusters, with areas in the same cluster being more similar, and areas in different clusters being dissimilar. The Ward linkage method with Euclidean distance was used. Results: The analysis of prescription drug consumption and expenditure from 2015 to 2021 revealed significant fluctuations and trends across various drug categories, age groups, and geographical areas. Notably, the quantity of prescriptions increased by 20% since 2015, while expenditure surged by over 30%, with significant spikes following the end of the MoU in 2019 and the onset of the pandemic in 2020. In terms of expenditure, antineoplastic and immunomodulation agents (category L) held the largest share, driven by the introduction of new, costly drugs. The expenditure per inhabitant revealed gender and age disparities, with older populations, particularly women, incurring higher costs. Geographically, drug expenditure, and consumption varied significantly, with distinct regional clusters identified. These clusters, while showing some overlap in consumption and expenditure patterns, also highlighted unique regional characteristics. Conclusions: The insights into prescription drug consumption and expenditure trends offer a valuable basis for developing targeted interventions aimed at optimizing healthcare resource allocation. Moreover, the findings underscore the importance of addressing regional and demographic disparities in pharmaceutical use, thereby contributing to more equitable and cost-effective healthcare strategies. More specifically, the age distribution of prescriptions shows the increase in younger ages, which, as a result, anticipates the overall increase in prescriptions. The knowledge of the most convex categories of medicine, as well as the percentages of the use of generic drugs, shows where interventions should be made, with financial incentives and information through new information channels. The geographic disparities recorded should lead to policies that help the residents of hard-to-reach areas to access prescriptions. In addition, the present study provides a strategic framework for policymakers and healthcare managers to guide future studies and inform decision-making processes. Full article
(This article belongs to the Special Issue Efficiency, Innovation, and Sustainability in Healthcare Systems)
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<p>Linear trend analysis, (<b>a</b>) volume; (<b>b</b>) expenditure.</p>
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<p>ABC analysis; (<b>a</b>) for quantity and (<b>b</b>) expenditure by ATC-1 categories, 2015–2021. (A: alimentary tract and metabolism; B: blood and blood-forming organs; C: cardiovascular system; D: dermatology; G: genito-urinary system and sexual hormones; H: systemic hormonal preparations; J: anti-infectives for systemic use; L: antineoplastic and immunomodulating; M: musculo-skeletal system; N: nervous system; P: antiparasitic products; R: respiratory system; S: sensory organs; V: various).</p>
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<p>Ratio (expenditure/quantity) per year and ATC-1 category (A: alimentary tract and metabolism; B: blood and blood-forming organs; C: cardiovascular system; D: dermatology; G: genito-urinary system and sexual hormones; H: systemic hormonal preparations; J: anti-infectives for systemic use; L: antineoplastic and immunomodulating; M: musculo-skeletal system; N: nervous system; P: antiparasitic products; R: respiratory system; S: sensory organs; V: various).</p>
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<p>Consumption and expenditure per capita by sex and age group, as a per cent of mean, 2015–2021.</p>
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<p>Cluster analysis. Dendrograms of regions by (<b>a</b>) quantities and (<b>b</b>) values.</p>
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32 pages, 58439 KiB  
Article
Relationship Between Spatial Form, Functional Distribution, and Vitality of Railway Station Areas Under Station-City Synergetic Development: A Case Study of Four Special-Grade Stations in Beijing
by Yuhan Sun, Bo Wan and Qiang Sheng
Sustainability 2024, 16(22), 10102; https://doi.org/10.3390/su162210102 - 19 Nov 2024
Viewed by 235
Abstract
The integration of railway stations into urban environments necessitates a detailed examination of their vitality and influencing factors. This study assesses urban vitality around four major railway stations in Beijing utilizing a variety of analytical models including Ordinary Least Squares, Geographically Weighted Regression, [...] Read more.
The integration of railway stations into urban environments necessitates a detailed examination of their vitality and influencing factors. This study assesses urban vitality around four major railway stations in Beijing utilizing a variety of analytical models including Ordinary Least Squares, Geographically Weighted Regression, Multi-Scale Geographically Weighted Regression, and machine learning approaches such as XGBoost 2.0.3, Random Forest 1.4.1.post1, and LightGBM 4.3.0. These analyses are grounded in Baidu heatmaps and examine relationships with spatial form, functional distribution, and spatial configuration. The results indicate significant associations between urban vitality and variables such as commercial density, average number of floors, integration, residential density, and housing prices, particularly in predicting weekday vitality. The MGWR model demonstrates enhanced fit and robustness, explaining 84.8% of the variability in vitality, while the Random Forest model displays the highest stability among the machine learning options, accounting for 76.9% of vitality variation. The integration of SHAP values with MGWR coefficients identifies commercial density as the most critical predictor, with the average number of floors and residential density also being key. These findings offer important insights for spatial planning in areas surrounding railway stations. Full article
(This article belongs to the Special Issue Urban Planning and Built Environment)
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<p>Passenger volume of Beijing Railway Station. Data source: China Railway Beijing Bureau Group Co., Ltd., Beijing, China.</p>
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<p>Passenger volume of the four major special-grade stations. Data source: China Railway Beijing Bureau Group Co., Ltd.</p>
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<p>Study area.</p>
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<p>Spatial road network parameter values.</p>
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<p>POI categories.</p>
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<p>Research framework diagram.</p>
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<p>Development intensity.</p>
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<p>Kernel density values of each function.</p>
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<p>Spatiotemporal variation of urban vitality on workdays.</p>
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<p>Spatiotemporal variation of urban vitality on weekends.</p>
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<p>Spatial distribution of MGWR regression coefficients.</p>
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<p>SHAP diagram of respective variables.</p>
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<p>SHAP diagram of various factors.</p>
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15 pages, 3280 KiB  
Article
Spatial and Temporal Analysis of Surface Displacements for Tailings Storage Facility Stability Assessment
by Wioletta Koperska, Paweł Stefaniak, Maria Stachowiak, Sergii Anufriiev, Ioannis Kakogiannos and Francisco Hernández-Ramírez
Appl. Sci. 2024, 14(22), 10715; https://doi.org/10.3390/app142210715 - 19 Nov 2024
Viewed by 306
Abstract
Monitoring the stability of tailings storage facilities (TSFs) is extremely important due to the catastrophic consequences of instability, which pose a threat to both the environment and human life. For this reason, numerous laboratory and field tests are carried out around dams. An [...] Read more.
Monitoring the stability of tailings storage facilities (TSFs) is extremely important due to the catastrophic consequences of instability, which pose a threat to both the environment and human life. For this reason, numerous laboratory and field tests are carried out around dams. An extensive database is collected as part of monitoring and field research. The in-depth analysis of available data can help monitor stability and predict disaster hazards. One of the important factors is displacement, including surface displacements—recorded by benchmarks as well as underground displacements—recorded by inclinometers. In this work, methods were developed to help assess the stability of the TSF in terms of surface and underground displacement based on the simulated data from geodetic benchmarks. The context of spatial correlation was investigated using hot spot analysis, which shows areas of greater risk, indicating the places of correlation of large and small displacements. The analysis of displacements versus time allowed us to indicate the growing exponential trend, thanks to which it is possible to forecast the trend of future displacements, as well as their velocity and acceleration, with the coefficient of determination of the trend matching reaching even 0.97. Additionally, the use of a geographically weighted regression model was proposed to predict the risk of shear relative to surface displacements. Full article
(This article belongs to the Special Issue Automation and Digitization in Industry: Advances and Applications)
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<p>Countries with the highest number of TSF dam failures (in the period 1915–2019).</p>
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<p>Sample Moran scatterplot.</p>
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<p>Moran scatterplot for displacement velocity (<b>a</b>) and displacement acceleration (<b>b</b>).</p>
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<p>Hot spot analysis result for velocity and acceleration of displacement for two sample simulations.</p>
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<p>Relationship between surface displacements and shear displacements for all measurement points.</p>
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<p>Relationship between surface displacements and shear displacements for the three selected locations.</p>
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<p>Shear risk at individual measuring points in three years.</p>
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<p>Trend prediction for total displacement and derivatives: velocity and acceleration for two selected (<b>a</b>,<b>b</b>) benchmarks.</p>
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12 pages, 655 KiB  
Article
High-Sensitivity Electrical Admittance Sensor with Regression Analysis for Measuring Mixed Electrolyte Concentrations
by Chun-Chi Chen, Chih-Hung Hung, Han-Xiang Zhu and Ji-Zun Chen
Sensors 2024, 24(22), 7379; https://doi.org/10.3390/s24227379 - 19 Nov 2024
Viewed by 218
Abstract
Electrolyte balance is essential for the proper functioning of the body, and imbalances can lead to various health issues, some of which may be life-threatening. Therefore, measuring electrolyte concentrations is becoming increasingly important, particularly for athletes engaged in high-intensity and prolonged physical activity. [...] Read more.
Electrolyte balance is essential for the proper functioning of the body, and imbalances can lead to various health issues, some of which may be life-threatening. Therefore, measuring electrolyte concentrations is becoming increasingly important, particularly for athletes engaged in high-intensity and prolonged physical activity. In this project, we developed a highly sensitive sensing device capable of accurately and rapidly measuring electrolyte concentrations in mixed solutions, providing precise analysis of trace electrolyte levels. The sensor device requires no complex operational procedures and can quickly complete measurements, making it well-suited for point-of-care applications. Integration of regression models further enhances the device’s ability to estimate concentrations in mixed electrolyte solutions. The test results demonstrate that the device can detect subtle concentration variations, with a precision as low as 0.5 mM. This proposed sensing device offers a cost-effective and efficient solution for real-time monitoring of electrolyte levels in healthcare. Full article
(This article belongs to the Special Issue Bioimpedance Measurements and Microelectrodes)
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<p>Equivalent circuit model for an electrolyte sample. (<b>a</b>) The equivalent circuit consists of the polarization impedance of the electrodes, represented by <math display="inline"><semantics> <msub> <mi>R</mi> <mi>P</mi> </msub> </semantics></math> and <math display="inline"><semantics> <msub> <mi>C</mi> <mi>P</mi> </msub> </semantics></math>, along with the sample impedance, represented by <math display="inline"><semantics> <msub> <mi>R</mi> <mi>S</mi> </msub> </semantics></math> and <math display="inline"><semantics> <msub> <mi>C</mi> <mi>S</mi> </msub> </semantics></math>. (<b>b</b>) The simplified equivalent circuit consists of the equivalent admittance <math display="inline"><semantics> <msub> <mi>Y</mi> <mi>T</mi> </msub> </semantics></math>, represented by conductance <math display="inline"><semantics> <msub> <mi>G</mi> <mi>T</mi> </msub> </semantics></math> and capacitance <math display="inline"><semantics> <msub> <mi>C</mi> <mi>T</mi> </msub> </semantics></math>.</p>
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<p>The electrolyte sensing system. The sinusoidal oscillator generates a sinusoidal signal to test the samples on the sensor device. The testing signal response is then amplified by a comparator-based operational amplifier (op-amp) and converted into digital signals by an analog-to-digital converter (ADC) for precise and coherent detection.</p>
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<p>The electrode sensing device. (<b>a</b>) The sensor device comprises coplanar copper electrodes on the PCB, utilizing a working electrode and a reference electrode array for measurements. The PCB also incorporates corner holes to ensure precise positioning. (<b>b</b>) The cross-sectional diagram of the sensing device shows the sensing electrodes embedded within the copper foil layer, covered with a thin insulation layer (PSR-2000) on the PCB.</p>
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<p>The comparator−based operational amplifier. (<b>a</b>) The comparator-based op-amp circuit amplifies the difference in signal response between the target admittance <math display="inline"><semantics> <mrow> <msub> <mi>Y</mi> <mn>0</mn> </msub> <mo>+</mo> <mo>Δ</mo> <mi>Y</mi> </mrow> </semantics></math> and the reference admittance <math display="inline"><semantics> <msub> <mi>Y</mi> <mn>1</mn> </msub> </semantics></math>. (<b>b</b>) The circuit of the signal generator produces two-phase driving signals with a 180° phase difference. The inverting op-amp can control the output amplitude by adjusting the variable resistor <math display="inline"><semantics> <msub> <mi>R</mi> <mn>1</mn> </msub> </semantics></math>. The Phase Shift (PS) networks can adjust the phase to synchronize the signal and minimize the phase difference by utilizing the variable resistance <math display="inline"><semantics> <msub> <mi>R</mi> <mn>2</mn> </msub> </semantics></math>.</p>
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<p>The comparator−based operational amplifier. (<b>a</b>) The comparator-based op-amp circuit amplifies the difference in signal response between the target admittance <math display="inline"><semantics> <mrow> <msub> <mi>Y</mi> <mn>0</mn> </msub> <mo>+</mo> <mo>Δ</mo> <mi>Y</mi> </mrow> </semantics></math> and the reference admittance <math display="inline"><semantics> <msub> <mi>Y</mi> <mn>1</mn> </msub> </semantics></math>. (<b>b</b>) The circuit of the signal generator produces two-phase driving signals with a 180° phase difference. The inverting op-amp can control the output amplitude by adjusting the variable resistor <math display="inline"><semantics> <msub> <mi>R</mi> <mn>1</mn> </msub> </semantics></math>. The Phase Shift (PS) networks can adjust the phase to synchronize the signal and minimize the phase difference by utilizing the variable resistance <math display="inline"><semantics> <msub> <mi>R</mi> <mn>2</mn> </msub> </semantics></math>.</p>
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<p>The admittance responses for deionized water and diluted NaCl solutions across concentrations ranging from <math display="inline"><semantics> <mrow> <mn>0.5</mn> </mrow> </semantics></math> to <math display="inline"><semantics> <mrow> <mn>4</mn> <mspace width="1.66656pt"/> </mrow> </semantics></math> mM are presented, with the blue line measured at <math display="inline"><semantics> <mrow> <mn>5</mn> <mspace width="1.66656pt"/> </mrow> </semantics></math> kHz and the red line measured at <math display="inline"><semantics> <mrow> <mn>10</mn> <mspace width="1.66656pt"/> </mrow> </semantics></math> kHz. The responses are normalized using deionized water as the reference, and each error bar shows the standard deviation of the measurements.</p>
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<p>The admittance responses for deionized water and diluted KCl solutions across concentrations ranging from <math display="inline"><semantics> <mrow> <mn>0.5</mn> </mrow> </semantics></math> to <math display="inline"><semantics> <mrow> <mn>4</mn> <mspace width="1.66656pt"/> </mrow> </semantics></math> mM are presented, with the blue line measured at <math display="inline"><semantics> <mrow> <mn>5</mn> <mspace width="1.66656pt"/> </mrow> </semantics></math> kHz and the red line measured at <math display="inline"><semantics> <mrow> <mn>10</mn> <mspace width="1.66656pt"/> </mrow> </semantics></math> kHz. The responses are normalized using deionized water as the reference, and each error bar shows the standard deviation of the measurements.</p>
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<p>The admittance measured at <math display="inline"><semantics> <mrow> <mn>5</mn> <mspace width="1.66656pt"/> </mrow> </semantics></math> kHz responses for deionized water and mixed NaCl and KCl solutions across concentrations ranging from <math display="inline"><semantics> <mrow> <mn>0.5</mn> </mrow> </semantics></math> to <math display="inline"><semantics> <mrow> <mn>4</mn> <mspace width="1.66656pt"/> </mrow> </semantics></math> mM. The (<b>a</b>) quadrature response and (<b>b</b>) in-phase response are normalized using deionized water as the reference solution. Each error bar indicates the standard deviation of the measurements.</p>
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<p>The admittance measured at <math display="inline"><semantics> <mrow> <mn>5</mn> <mspace width="1.66656pt"/> </mrow> </semantics></math> kHz responses for deionized water and mixed NaCl and KCl solutions across concentrations ranging from <math display="inline"><semantics> <mrow> <mn>0.5</mn> </mrow> </semantics></math> to <math display="inline"><semantics> <mrow> <mn>4</mn> <mspace width="1.66656pt"/> </mrow> </semantics></math> mM. The (<b>a</b>) quadrature response and (<b>b</b>) in-phase response are normalized using deionized water as the reference solution. Each error bar indicates the standard deviation of the measurements.</p>
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<p>The admittance measured at <math display="inline"><semantics> <mrow> <mn>10</mn> <mspace width="1.66656pt"/> </mrow> </semantics></math> kHz responses for deionized water and mixed NaCl and KCl solutions across concentrations ranging from <math display="inline"><semantics> <mrow> <mn>0.5</mn> </mrow> </semantics></math> to <math display="inline"><semantics> <mrow> <mn>4</mn> <mspace width="1.66656pt"/> </mrow> </semantics></math> mM. The (<b>a</b>) quadrature response and (<b>b</b>) in-phase response are normalized using deionized water as the reference solution. Each error bar indicates the standard deviation of the measurements.</p>
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13 pages, 4506 KiB  
Article
Identification of Key Soil Quality Indicators for Predicting Mean Annual Increment in Pinus patula Forest Plantations in Tanzania
by Joshua Maguzu, Salim M. Maliondo, Ilstedt Ulrik and Josiah Zephaniah Katani
Forests 2024, 15(11), 2042; https://doi.org/10.3390/f15112042 - 19 Nov 2024
Viewed by 236
Abstract
There is an unexplored knowledge gap regarding the relationship between soil quality and mean annual increment (MAI) in forest plantations in Tanzania. Therefore, this study aimed to identify soil quality indicators and their impact on the mean annual increment (MAI) of Pinus patula [...] Read more.
There is an unexplored knowledge gap regarding the relationship between soil quality and mean annual increment (MAI) in forest plantations in Tanzania. Therefore, this study aimed to identify soil quality indicators and their impact on the mean annual increment (MAI) of Pinus patula at Sao Hill (SHFP) and Shume forest plantations (SFP) in Tanzania. The forests were stratified into four site classes based on management records. Tree growth data were collected from 3 quadrat plots at each site, resulting in 12 plots in each plantation, while soil samples were taken from 0 to 40 cm soil depth. Analysis of variance examined the variation in soil quality indicators between site classes at two P. patula plantation sites. Covariance analysis assessed the differences in MAI and stand variables across various site classes, taking into account the differing ages of some stands, with stand age serving as a covariate. Linear regression models explored the relationship between soil quality indicators and MAI, while partial least squares regression predicted MAI using soil quality indicators. The results showed that, at SHFP, sand, organic carbon (OC), cation exchange capacity, calcium (Ca), magnesium (Mg), and available P varied significantly between site classes, while silt, clay, and available P varied significantly at SFP. At SHFP, sand and clay content were positively correlated with MAI, while at SFP, silt content, available P (Avail P), potassium (K), Ca, and Mg showed significant positive correlations. Soil quality indicators, including physical and chemical properties (porosity, clay percentages, sand content, and OC) and only chemical (K, Mg, Avail P, and soil pH) properties were better predictors of the forest mean annual increment at SHFP and SFP, respectively. This study underscores the importance of monitoring the quality of soils in enhancing MAI and developing soil management strategies for long-term sustainability in forests production. Full article
(This article belongs to the Special Issue Forest Soil Physical, Chemical, and Biological Properties)
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Figure 1
<p>Locations of soil sampling plots at Sao Hill and Shume Forest Plantations in Tanzania.</p>
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<p>Variation of soil physical properties among the site classes. Plotted above the error line, distinct lowercase letters signify significant differences among site classes at Sao Hill and Shume Forest Plantations.</p>
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<p>Variation of soil chemical properties among the site classes. Plotted above the error line, distinct lowercase letters signify significant differences among site classes at Sao Hill and Shume Forest Plantations in Tanzania.</p>
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<p>Distribution difference of mean annual increment and other stand attributes in different site classes. Above the error line, different small letters indicate that there are significant differences among different site classes.</p>
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<p>Illustrates the correlations between soil physical properties and mean annual increment. The fitted linear relationships reflect the potential relationship of MAI-physical properties interactions at Sao Hill and Shume Forest Plantations in Tanzania.</p>
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<p>Illustrates the correlations between soil chemical properties and mean annual increment. The fitted linear relationships reflect the potential relationship of MAI-chemical properties interactions at Sao Hill and Shume Forest Plantations in Tanzania.</p>
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20 pages, 6191 KiB  
Article
How Do Transformers Model Physics? Investigating the Simple Harmonic Oscillator
by Subhash Kantamneni, Ziming Liu and Max Tegmark
Entropy 2024, 26(11), 997; https://doi.org/10.3390/e26110997 (registering DOI) - 19 Nov 2024
Viewed by 164
Abstract
How do transformers model physics? Do transformers model systems with interpretable analytical solutions or do they create an “alien physics” that is difficult for humans to decipher? We have taken a step towards demystifying this larger puzzle by investigating the simple harmonic oscillator [...] Read more.
How do transformers model physics? Do transformers model systems with interpretable analytical solutions or do they create an “alien physics” that is difficult for humans to decipher? We have taken a step towards demystifying this larger puzzle by investigating the simple harmonic oscillator (SHO), x¨+2γx˙+ω02x=0, one of the most fundamental systems in physics. Our goal was to identify the methods transformers use to model the SHO, and to do so we hypothesized and evaluated possible methods by analyzing the encoding of these methods’ intermediates. We developed four criteria for the use of a method within the simple test bed of linear regression, where our method was y=wx and our intermediate was w: (1) Can the intermediate be predicted from hidden states? (2) Is the intermediate’s encoding quality correlated with the model performance? (3) Can the majority of variance in hidden states be explained by the intermediate? (4) Can we intervene on hidden states to produce predictable outcomes? Armed with these two correlational (1,2), weak causal (3), and strong causal (4) criteria, we determined that transformers use known numerical methods to model the trajectories of the simple harmonic oscillator, specifically, the matrix exponential method. Our analysis framework can conveniently extend to high-dimensional linear systems and nonlinear systems, which we hope will help reveal the “world model” hidden in transformers. Full article
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Figure 1
<p>We aimed to understand how transformers model physics through the study of meaningful intermediates. We trained transformers to model simple harmonic oscillator (SHO) trajectories, and we used our developed criteria of intermediates to show that transformers use known numerical methods to model the SHO.</p>
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<p>We plotted the <math display="inline"><semantics> <msup> <mi>R</mi> <mn>2</mn> </msup> </semantics></math> of the Taylor probes for the intermediate <math display="inline"><semantics> <mi mathvariant="bold-italic">w</mi> </semantics></math> within the models trained on the task <math display="inline"><semantics> <mrow> <mi mathvariant="bold-italic">Y</mi> <mo>=</mo> <mi mathvariant="bold-italic">wX</mi> </mrow> </semantics></math> (linear regression). We saw that the larger models had <math display="inline"><semantics> <mi mathvariant="bold-italic">w</mi> </semantics></math> encoded, often linearly, with little gain as we moved to higher-degree Taylor probes, while the smaller models did not have <math display="inline"><semantics> <mi mathvariant="bold-italic">w</mi> </semantics></math> encoded.</p>
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<p>We tested the correlation between model performance and the encoding of <math display="inline"><semantics> <mi mathvariant="bold-italic">w</mi> </semantics></math> on 5 of our 25 linear regression models of evenly spaced performance quality. We plotted normalized values for the error of the encoding (<math display="inline"><semantics> <mrow> <mn>1</mn> <mo>−</mo> <msubsup> <mi>R</mi> <mi>w</mi> <mn>2</mn> </msubsup> </mrow> </semantics></math>) in red and the mean squared error of the model (<math display="inline"><semantics> <msub> <mrow> <mi>M</mi> <mi>S</mi> <mi>E</mi> </mrow> <mi>M</mi> </msub> </semantics></math>) in blue. We found that the ability of the best-performing models to in-context learn was highly correlated with their encoding of <math display="inline"><semantics> <mi mathvariant="bold-italic">w</mi> </semantics></math> (<math display="inline"><semantics> <mrow> <msup> <mi>R</mi> <mn>2</mn> </msup> <mrow> <mo>(</mo> <mi>M</mi> <mi>S</mi> <mi>E</mi> <mo>,</mo> <mi>w</mi> <mo>)</mo> </mrow> </mrow> </semantics></math>.</p>
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<p>Left: We plotted <math display="inline"><semantics> <mrow> <mo movablelimits="true" form="prefix">max</mo> <mo>(</mo> <mover accent="true"> <msup> <mi>R</mi> <mn>2</mn> </msup> <mo stretchy="false">¯</mo> </mover> <mo>)</mo> </mrow> </semantics></math> of the reverse probe from <math display="inline"><semantics> <mrow> <mo>[</mo> <mi>w</mi> <mo>,</mo> <msup> <mi>w</mi> <mn>2</mn> </msup> <mo>]</mo> <mo>→</mo> <mi>H</mi> <mi>S</mi> </mrow> </semantics></math> across all the linear regression models, and we found that the intermediate <math display="inline"><semantics> <mi mathvariant="bold-italic">w</mi> </semantics></math> could explain significant amounts of variance in the model hidden states. Right: We intervened, using reverse probes to make all the models output <math display="inline"><semantics> <mrow> <msup> <mi mathvariant="bold-italic">w</mi> <mo mathvariant="bold">′</mo> </msup> <mo>=</mo> <mn>0.5</mn> </mrow> </semantics></math>. This intervention failed (16/25), it was partially successful nonlinearly (2/25) or linearly (3/25), or it was successful (4/25). We noted the empirically observed <math display="inline"><semantics> <mi mathvariant="bold-italic">w</mi> </semantics></math> as <math display="inline"><semantics> <mover accent="true"> <mi>w</mi> <mo stretchy="false">^</mo> </mover> </semantics></math> calculated by <math display="inline"><semantics> <mrow> <mover accent="true"> <mi>y</mi> <mo stretchy="false">^</mo> </mover> <mo>/</mo> <mi>x</mi> </mrow> </semantics></math> where <math display="inline"><semantics> <mover accent="true"> <mi>y</mi> <mo stretchy="false">^</mo> </mover> </semantics></math> was the output of the intervened transformer and <span class="html-italic">x</span> was the input.</p>
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<p>We analyzed the intermediates of our undamped harmonic oscillator models, and we found all three methods encoded, with the matrix exponential method best represented. This provided initial correlational evidence for all three methods.</p>
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<p>We found that the better-performing undamped harmonic oscillator models had intermediates of all methods better encoded, but this correlation was strongest in magnitude and slope for the matrix exponential method. This was additional correlational evidence for all three methods.</p>
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<p>We found that the intermediates from all three methods could explain some variance in the undamped harmonic oscillator model hidden states, but that the matrix exponential method was the most consistent and successful by a wide margin.</p>
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<p>For each undamped harmonic oscillator model and method, we replaced the hidden state in <a href="#entropy-26-00997-f007" class="html-fig">Figure 7</a> with the reverse probe of the intermediate. We can see that this intervention was consistently the best performing for the matrix exponential method by an order of magnitude, and that 18/25 models performed better than our baseline of guessing.</p>
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<p>We varied the value of <math display="inline"><semantics> <mrow> <mi mathvariant="sans-serif">Δ</mi> <mi>t</mi> </mrow> </semantics></math> used in the intermediates, and we used the reverse probes from <a href="#entropy-26-00997-f007" class="html-fig">Figure 7</a> to generate hidden states from these intermediates. We performed this operation on two undamped harmonic oscillator models, which had the best linear multistep/Taylor expansion (<math display="inline"><semantics> <mrow> <mi>L</mi> <mo>=</mo> <mn>4</mn> <mo>,</mo> <mi>H</mi> <mo>=</mo> <mn>4</mn> </mrow> </semantics></math>) and matrix exponential (<math display="inline"><semantics> <mrow> <mi>L</mi> <mo>=</mo> <mn>4</mn> <mo>,</mo> <mi>H</mi> <mo>=</mo> <mn>8</mn> </mrow> </semantics></math>) reverse probes, respectively, and we found that the matrix exponential was consistently most robust for interventions. The baseline was if our model only predicted the mean of the dataset.</p>
Full article ">Figure A1
<p>We found that the linear regression models were able to generalize to out-of-distribution test data with <math display="inline"><semantics> <mrow> <mn>0.75</mn> <mo>≤</mo> <mo>|</mo> <mi>w</mi> <mo>|</mo> <mo>≤</mo> <mn>1</mn> </mrow> </semantics></math>.</p>
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<p>We calculated the mean of the <math display="inline"><semantics> <msup> <mi>R</mi> <mn>2</mn> </msup> </semantics></math> of probes for <math display="inline"><semantics> <mrow> <mi>f</mi> <mo>(</mo> <mi>w</mi> <mo>)</mo> </mrow> </semantics></math> across all layers of the transformer and we annotated each model with its highest mean score, <math display="inline"><semantics> <mrow> <mo movablelimits="true" form="prefix">max</mo> <mo>(</mo> <mover accent="true"> <msup> <mi>R</mi> <mn>2</mn> </msup> <mo stretchy="false">¯</mo> </mover> <mo>)</mo> </mrow> </semantics></math>. When <math display="inline"><semantics> <mrow> <mi>f</mi> <mo>(</mo> <mi>w</mi> <mo>)</mo> </mrow> </semantics></math> was linear (<b>left</b>) and quadratic (<b>middle</b>), we observed a striking phase transition of encoding based on model size, demarked by the red dashed line. If <math display="inline"><semantics> <mi mathvariant="bold-italic">w</mi> </semantics></math> was encoded, it was mostly encoded linearly, with the <math display="inline"><semantics> <mrow> <mo>(</mo> <mi>L</mi> <mo>,</mo> <mi>H</mi> <mo>)</mo> <mo>=</mo> <mo>(</mo> <mn>5</mn> <mo>,</mo> <mn>2</mn> <mo>)</mo> <mo>,</mo> <mo>(</mo> <mn>4</mn> <mo>,</mo> <mn>32</mn> <mo>)</mo> <mo>,</mo> <mo>(</mo> <mn>2</mn> <mo>,</mo> <mn>8</mn> <mo>)</mo> </mrow> </semantics></math> models showing signs of a quadratic representation of <math display="inline"><semantics> <mi mathvariant="bold-italic">w</mi> </semantics></math>. We did not see any meaningful gain in encoding when extending the Taylor probe to degree <math display="inline"><semantics> <mrow> <mi>n</mi> <mo>&gt;</mo> <mn>2</mn> </mrow> </semantics></math> (<b>right</b>). For the models where <math display="inline"><semantics> <mrow> <mi>f</mi> <mo>(</mo> <mi>w</mi> <mo>)</mo> </mrow> </semantics></math> was well represented, it often happened in the attention layer. This was possibly because the attention layer aggregated all past estimates of <math display="inline"><semantics> <mrow> <mi>f</mi> <mo>(</mo> <mi>w</mi> <mo>)</mo> </mrow> </semantics></math> into an updated estimate.</p>
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<p>Better-performing models generally had better encodings of <math display="inline"><semantics> <mi mathvariant="bold-italic">w</mi> </semantics></math>, while worse-performing models generally had worse encodings (other than one outlier in the top-right).</p>
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<p>An intuitive picture for a simple harmonic oscillator is a mass oscillating on a spring (<b>left</b>). The trajectory of the SHO can be fully parameterized by the value of <math display="inline"><semantics> <mrow> <mi>x</mi> <mo>,</mo> <mi>v</mi> </mrow> </semantics></math> at various timesteps (<b>middle</b>), and we found that models trained to predict undamped SHO trajectories are able to generalize to out-of-distribution test data with in-context examples (<b>right</b>).</p>
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<p>We visualize the evolution of encodings across all the methods, with context length for the best-performing undamped model.</p>
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<p>We found that our choice of <span class="html-italic">j</span> in the intermediate for the Taylor expansion method (<math display="inline"><semantics> <msup> <mrow> <mo>(</mo> <mi>A</mi> <mi mathvariant="sans-serif">Δ</mi> <mi>t</mi> <mo>)</mo> </mrow> <mi>j</mi> </msup> </semantics></math>) had little effect on our results or conclusions about the undamped harmonic oscillator (shown for criterion 1).</p>
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<p>Regardless of which quantities we intervened on, our general results were robust for criterion 4 for the undamped harmonic oscillator.</p>
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<p>We generated synthetic hidden states from the matrix exponential intermediates and found that this naturally resulted in values for criterion 1,3 for the linear multistep and Taylor expansion methods that were close to those we observe in <a href="#entropy-26-00997-t002" class="html-table">Table 2</a>. This is correlational evidence that the matrix exponential method was potentially solely used by the transformer, and that the values for the other two methods were byproducts. These byproducts could arise because <math display="inline"><semantics> <mrow> <msup> <mi>e</mi> <mrow> <mi>A</mi> <mi mathvariant="sans-serif">Δ</mi> <mi>t</mi> </mrow> </msup> <mo>=</mo> <msub> <mo>∑</mo> <mi>j</mi> </msub> <msup> <mrow> <mo>(</mo> <mi>A</mi> <mi mathvariant="sans-serif">Δ</mi> <mi>t</mi> <mo>)</mo> </mrow> <mi>j</mi> </msup> <mo>/</mo> <mi>j</mi> </mrow> </semantics></math>.</p>
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<p>We generated data for the underdamped and overdamped harmonic oscillators following the procedure detailed in <a href="#sec3-entropy-26-00997" class="html-sec">Section 3</a>, and we visualize the sample curves in the left-most plot. From both the analytical equations and the plotted curves, we see that the underdamped and the overdamped data followed very different trajectories. Amazingly, on the right-most plot we find that the transformers trained on the underdamped data generalized to overdamped data. This implies that our transformer was using a similar method to calculate both, otherwise this generalization would be impossible. We hypothesize that our “AI Physicist” was using one of the numerical methods from the undamped case. Note that the “damped” oscillator was trained on equal parts underdamped and overdamped data.</p>
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<p>We observe that the intermediates for all three methods were encoded, but they were less than the undamped case in <a href="#entropy-26-00997-f005" class="html-fig">Figure 5</a>. The linear multistep was roughly as prominent as the matrix exponential method, which was also a departure from the undamped case.</p>
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<p>We see that, generally, the better-performing models exhibited stronger encodings of intermediates, while the worse-performing models exhibited weaker encodings. These trends were not as strong as the undamped case, shown in <a href="#entropy-26-00997-f006" class="html-fig">Figure 6</a>. Like criterion 1 in <a href="#entropy-26-00997-f0A10" class="html-fig">Figure A10</a>, we see that the linear multistep method was competitive with the matrix exponential method.</p>
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<p>Multiple methods represented nontrivial amounts of variance in the hidden states, but even all the methods combined (right) explained less than a quarter of the variance in the hidden states.</p>
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<p>We see that the encoding strength of the intermediates decayed across all the methods with context length. This similarly matched the natural decay to 0 of the damped harmonic oscillator, and it is one potential explanation for why our methods were not as prominent in the damped vs. undamped cases, for which the encoding quality did not decay with context length (<a href="#entropy-26-00997-f0A13" class="html-fig">Figure A13</a>). While this is a general observation across the models, we visualize the <math display="inline"><semantics> <mrow> <mi>L</mi> <mo>=</mo> <mn>4</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mi>H</mi> <mo>=</mo> <mn>32</mn> </mrow> </semantics></math> model because it had the strongest encoding of intermediates from <a href="#entropy-26-00997-f0A10" class="html-fig">Figure A10</a>.</p>
Full article ">Figure A14
<p>We found that our choice of <span class="html-italic">j</span> in the intermediate for the Taylor expansion method (<math display="inline"><semantics> <msup> <mrow> <mo>(</mo> <mi>A</mi> <mi mathvariant="sans-serif">Δ</mi> <mi>t</mi> <mo>)</mo> </mrow> <mi>j</mi> </msup> </semantics></math> had a major effect on the encoding quality, unlike the undamped case visualized in <a href="#entropy-26-00997-f0A6" class="html-fig">Figure A6</a>. We see that <math display="inline"><semantics> <mrow> <mi>j</mi> <mo>&gt;</mo> <mn>3</mn> </mrow> </semantics></math> was very poorly represented in the transformer, which implies that if the transformer was using the Taylor expansion for the underdamped spring, it would likely be of order <math display="inline"><semantics> <mrow> <mi>k</mi> <mo>=</mo> <mn>3</mn> </mrow> </semantics></math> or less.</p>
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