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18 pages, 867 KiB  
Article
Enhanced Kalman Filter with Dummy Nodes and Prediction Confidence for Bipartite Graph Matching in 3D Multi-Object Tracking
by Shaoyu Sun, Chunyang Wang, Bo Xiao, Xuelian Liu, Chunhao Shi, Rongliang Sun and Ruijie Han
Electronics 2024, 13(24), 4950; https://doi.org/10.3390/electronics13244950 (registering DOI) - 16 Dec 2024
Abstract
Kalman filter (KF)-based methods for 3D multi-object tracking (MOT) in autonomous driving often face challenges when detections are missed due to occlusions, sensor noise, or objects moving out of view. This leads to data association failures and cumulative errors in the update stage, [...] Read more.
Kalman filter (KF)-based methods for 3D multi-object tracking (MOT) in autonomous driving often face challenges when detections are missed due to occlusions, sensor noise, or objects moving out of view. This leads to data association failures and cumulative errors in the update stage, as traditional Kalman filters rely on linear state estimates that can drift significantly without measurement updates. To address this issue, we propose an enhanced Kalman filter with dummy nodes and prediction confidence (KDPBTracker) to improve tracking continuity and robustness in these challenging scenarios. First, we designed dummy nodes to act as pseudo-observations generated from past and nearby frame detections in cases of missed detection, allowing for stable associations within the data association matrix when real detections were temporarily unavailable. To address the uncertainty in these dummy nodes, we then proposed a prediction confidence score to reflect their reliability in data association. Additionally, we modified a constant acceleration motion model combined with position-based heading estimation to better control high-dimensional numerical fluctuations in the covariance matrix, enhancing the robustness of the filtering process, especially in highly dynamic scenarios. We further designed bipartite graph data association to refine Kalman filter updates by integrating geometric and motion information weighted by the prediction confidence of the dummy nodes. Finally, we designed a confidence-based retention track management module to dynamically manage track continuity and deletion based on temporal and reliability thresholds, improving tracking accuracy in complex environments. Our method achieves state-of-the-art performance on the nuScenes validation set, improving AMOTA by 1.8% over the baseline CenterPoint. Evaluation on the nuScenes dataset demonstrates that KDPBTracker significantly improves tracking accuracy, reduces ID switches, and enhances overall tracking continuity under challenging conditions. Full article
(This article belongs to the Section Computer Science & Engineering)
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<p><b>Illustration of tracking challenges and solutions.</b> Our method is motivated by the challenges encountered in our previous works: (<b>A</b>) Bidirectional Cross-Frame Memory for Single-Object Tracking (SOT) in STMDTracker, (<b>B</b>) Bipartite Graph Matching for Multi-Object Tracking (MOT) in GMTracker, and (<b>C</b>) the Enhanced Kalman Filter with Dummy Detection Nodes for Bipartite Graph Matching in MOT, embodied in the KDPBTracker as a solution to these challenges in MOT.</p>
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<p><b>The overall architecture of KDPBTracker.</b> The proposed KDPBTracker framework integrates dummy nodes with prediction confidence to address missed detections in 3D MOT. In the Dummy Detection Operation module, dummy nodes are generated based on past and future detection states, with an uncertainty score modulating their influence in data association. The Kalman Filter Motion Prediction module provides state estimates, which, together with the detected and dummy nodes, are used to construct a bipartite graph with a geometric and motion cost matrix. The cost matrix, weighted by dummy node prediction confidence to represent uncertainty, refines the Kalman filter updates for improved robustness. Finally, the Track Management Module applies confidence thresholds for track retention and deletion, enhancing tracking accuracy and continuity in complex environments.</p>
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<p><b>Dummy node motivation.</b> Kalman Prediction Error Accumulation due to Missed Detection: This diagram illustrates how errors accumulate in Kalman filter predictions when missed detections occur. The predicted trajectory (blue line) deviates from the true trajectory (green line) due to missed detections (empty circles). A dummy node (red circle) is introduced to correct the prediction using linear interpolation based on past and future detection states. This compensates for accumulated errors, preventing further divergence in future predictions (T + n).</p>
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<p><b>Bipartite graph data association.</b> This bipartite graph is constructed between predicted states and detected states. Instead of using a binary (0/1) association, the association matrix is built using geometric and motion similarity scores between predicted and detected objects. By reducing the complexity from <math display="inline"><semantics> <mrow> <mo>(</mo> <mi>D</mi> <mo>+</mo> <mi>P</mi> <mo>)</mo> <mo>×</mo> <mo>(</mo> <mi>D</mi> <mo>+</mo> <mi>P</mi> <mo>)</mo> </mrow> </semantics></math> to <math display="inline"><semantics> <mrow> <mo>(</mo> <mi>D</mi> <mo>×</mo> <mi>P</mi> <mo>)</mo> </mrow> </semantics></math>, where D is the number of detected objects and P is the number of predicted objects, the association matrix becomes more efficient while maintaining accuracy. This matrix now contains similarity scores, improving data association and matching.</p>
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<p>Comparison AMOTA results of overall and seven classes, namely bicycle, bus, car, motorcycle, pedestrian, trailer, and truck, in the NuScenes val set.</p>
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<p>Effect of future frames for dummy nodes and track retention.</p>
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<p>Dummy detection visualization.</p>
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15 pages, 1025 KiB  
Article
BLV-CoCoMo Dual qPCR Assay Targeting LTR Region for Quantifying Bovine Leukemia Virus: Comparison with Multiplex Real-Time qPCR Assay Targeting pol Region
by Sonoko Watanuki, Aronggaowa Bao, Etsuko Saitou, Kazuyuki Shoji, Masaki Izawa, Mitsuaki Okami, Yasunobu Matsumoto and Yoko Aida
Pathogens 2024, 13(12), 1111; https://doi.org/10.3390/pathogens13121111 (registering DOI) - 16 Dec 2024
Abstract
The proviral load (PVL) of the bovine leukemia virus (BLV) is a useful index for estimating disease progression and transmission risk. Real-time quantitative PCR techniques are widely used for PVL quantification. We previously developed a dual-target detection method, the “Liquid Dual-CoCoMo assay”, that [...] Read more.
The proviral load (PVL) of the bovine leukemia virus (BLV) is a useful index for estimating disease progression and transmission risk. Real-time quantitative PCR techniques are widely used for PVL quantification. We previously developed a dual-target detection method, the “Liquid Dual-CoCoMo assay”, that uses the coordination of common motif (CoCoMo) degenerate primers. This method can detect two genes simultaneously using a FAM-labeled minor groove binder (MGB) probe for the BLV long terminal repeat (LTR) region and a VIC-labeled MGB probe for the BoLA-DRA gene. In this study, we evaluated the diagnostic and analytical performance of the Dual-CoCoMo assay targeting the LTR region by comparing its performance against the commercially available Takara multiplex assay targeting the pol region. The diagnostic sensitivity and specificity of the Liquid Dual-CoCoMo assay based on the diagnostic results of the ELISA or original Single-CoCoMo qPCR were higher than those of the Takara multiplex assay. Furthermore, using a BLV molecular clone, the analytical sensitivity of our assay was higher than that of the Takara multiplex assay. Our results provide the first evidence that the diagnostic and analytical performances of the Liquid Dual-CoCoMo assay are better than those of commercially available multiplex assays that target the pol region. Full article
(This article belongs to the Section Viral Pathogens)
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<p>BLV PLVs of 121 cows determined by Liquid Dual-CoCoMo and Takara multiplex assays. (<b>A</b>) The PVLs of 121 cows, excluding BLV-uninfected cattle, were determined from those samples in duplicate using the Liquid Dual-CoCoMo (yellow circle) and Takara multiplex (blue triangle) assays. The PVL was expressed as the number of copies per 10<sup>5</sup> cells. (<b>B</b>) Comparison of PVLs measured by Liquid Dual-CoCoMo (yellow) and Takara multiplex (blue) assays. The means are denoted by the black bars. The <span class="html-italic">p</span>-values were calculated using a paired <span class="html-italic">t</span>-test. Asterisks indicate significant differences (**** <span class="html-italic">p</span> &lt; 0.0001).</p>
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<p>Correlation between the BLV PVLs measured by the Liquid Dual-CoCoMo and Takara multiplex assays. The PVLs of 121 cows, excluding BLV-uninfected cattle, were determined from those samples by duplicate, using the Liquid Dual-CoCoMo and Takara multiplex assays. The correlation between the PVLs measured by the Liquid Dual-CoCoMo and Takara multiplex assays was evaluated using Pearson’s correlation coefficient (<span class="html-italic">r</span>); <span class="html-italic">p</span>-values are indicated in the graphs. The dotted line represents the approximate curve.</p>
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14 pages, 1482 KiB  
Article
The Association of Dietary Polyamines with Mortality and the Risk of Cardiovascular Disease: A Prospective Study in UK Biobank
by Su Han, Mingxia Qian, Na Zhang, Rui Zhang, Min Liu, Jiangbo Wang, Furong Li, Liqiang Zheng and Zhaoqing Sun
Nutrients 2024, 16(24), 4335; https://doi.org/10.3390/nu16244335 (registering DOI) - 16 Dec 2024
Abstract
Background: Polyamines, including spermidine (SPD), spermine (SPM) and putrescine (PUT), are essential for cellular physiology and various cellular processes. This study aimed to examine the associations of dietary polyamines intake and all-cause mortality and incident cardiovascular disease (CVD). Methods: This prospective cohort study [...] Read more.
Background: Polyamines, including spermidine (SPD), spermine (SPM) and putrescine (PUT), are essential for cellular physiology and various cellular processes. This study aimed to examine the associations of dietary polyamines intake and all-cause mortality and incident cardiovascular disease (CVD). Methods: This prospective cohort study included 184,732 participants without CVD at baseline from the UK Biobank who had completed at least one dietary questionnaire. Diet was assessed using Oxford WebQ, a web-based 24 h recall questionnaire, with polyamines intakes estimated from previous studies. Cox proportional models with restricted cubic splines were employed to investigate nonlinear associations. The primary endpoint was all-cause mortality or incident CVD (including CVD death, coronary heart disease and stroke). Results: During a median follow-up period of 11.5 years, 7348 (3.9%) participants died and 12,316 (6.5%) developed incident CVD. Polyamines intake showed nonlinear associations with all-cause mortality and incident CVD (P for nonlinear < 0.01). Compared to the lowest quintile group of dietary polyamines intake (≤17.4 mg/day), the quintile 2 to 5 groups demonstrated a reduced risk of all-cause mortality, with the lowest risk in quintile 2 group (>17.4–22.3 mg/day) (HR:0.82, 95% CI: 0.76–0.88). Similar results were observed for incident CVD, with the lowest risk in the quintile 4 group (>27.1–33.5 mg/day) (HR: 0.86, 95% CI: 0.82–0.92). Conclusions: We found that dietary polyamines intake was associated with a lower risk of all-cause mortality or incident CVD. Furthermore, our study identified an optimal range of dietary polyamines intake. Full article
(This article belongs to the Special Issue Diet, Nutrition and Cardiovascular Health)
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<p>The association between dietary polyamines intake and all-cause mortality or incident CVD and components of CVD (CVD death, CHD and stroke). Mode1 1: Analyses adjusted for age and sex. Model 2: Analyses adjusted for age, sex, ethnicity, Townsend deprivation index, education level, systolic blood pressure, body mass index, physical activity, smoking status, alcohol status, sleep duration, energy, hypertension, diabetes, hypercholesteremia, antihypertensive treatment, lipid treatment and insulin treatment. Indications: quintile 2 to 5 groups demonstrated a consistent risk reduction in all-cause mortality, with the quintile 2 group having the lowest risk (&gt;17.4–22.3 mg/day). This pattern was also seen for incident CVD, with the lowest risk reduction in quintile 4 group (&gt;27.1–33.5 mg/day). Optimal polyamine intake for CVD components was observed in quintile 2 (&gt;17.4–22.3 mg/day) for CVD death and quintile 4 (&gt;27.1–33.5 mg/day) for incident CHD and stroke.</p>
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<p>The association between dietary polyamines intake and all-cause mortality or incident CVD. Knots were placed at the 25th, 50th, 75th and 100th percentiles of the polyamines intake distribution. Analyses adjusted for age, sex, ethnicity, Townsend deprivation index, education level, systolic blood pressure, body mass index, physical activity, smoking status, alcohol status, sleep duration, energy, hypertension, diabetes, hypercholesteremia, antihypertensive treatment, lipid treatment and insulin treatment. Components of CVD (CVD death, CHD and stroke) were also analyzed. Shaded areas represent 95% confidence intervals. Indications: Moderate increases in polyamines were associated with a substantial reduction in the risk of all-cause mortality and incident CVD. (Nonlinear <span class="html-italic">p</span> &lt; 0.001). Similar results were found in the composition of CVD events.</p>
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<p>Association between dietary polyamines intake and all-cause mortality or incident CVD stratified by potential risk factors. Analyses adjusted for age, sex, ethnicity, Townsend deprivation index, education level, systolic blood pressure, body mass index, physical activity, smoking status, alcohol status, sleep duration, energy, hypertension, diabetes, hypercholesteremia, antihypertensive treatment, lipid treatment and insulin treatment. Indications: Significant interactions were found between polyamines intake and education level, sleep duration and hypercholesteremia on all-cause mortality; for incident CVD, the associations were stronger among those with a higher education level, without diabetes, or with lower CHD and stroke genetic predisposition scores.</p>
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14 pages, 472 KiB  
Article
Lifestyle Factors and Associations with Individual and Comorbid Cardiometabolic and Pulmonary Disease Among U.S. Adults
by Osayande Agbonlahor, Delvon T. Mattingly, Maggie K. Richardson, Joy L. Hart, Alison C. McLeish and Kandi L. Walker
Int. J. Environ. Res. Public Health 2024, 21(12), 1674; https://doi.org/10.3390/ijerph21121674 (registering DOI) - 16 Dec 2024
Abstract
Background: Although lifestyle factors have been linked to chronic diseases among adults, their association with diagnosed individual and comorbid cardiometabolic (CMD) and pulmonary disease (PD) is not fully known. This study aimed to examine the associations between lifestyle factors and individual and comorbid [...] Read more.
Background: Although lifestyle factors have been linked to chronic diseases among adults, their association with diagnosed individual and comorbid cardiometabolic (CMD) and pulmonary disease (PD) is not fully known. This study aimed to examine the associations between lifestyle factors and individual and comorbid CMD and PD among U.S. adults. Methods: We used cross-sectional data from the 2017–2020 National Health and Nutrition Examination Survey (n = 7394). Health care provider’s diagnosis of CMD and PD and lifestyle factors (i.e., past 5-day tobacco use, past 12-month alcohol use, diet, sleep troubles, and physical activity) were assessed. Adjusted odds ratios were estimated using logistic and multinomial logistic regression. Results: Trouble sleeping was associated with increased odds of CMD (OR: 2.47) and PD (OR: 2.29) individually, while physical activity was associated with lower odds (OR: 0.75, OR: 0.77). Past 5-day tobacco (OR: 2.36) and past year alcohol (OR: 1.61) use were associated with increased PD odds. Lifestyle factors were associated with increased odds of comorbid CMD and PD. Conclusions: Lifestyle factors were associated with increased odds of individual and comorbid CMD and PD among adults. CMD and PD prevention should involve promoting lifestyle modification and implementation of policies that eliminate structural barriers to healthy lifestyle adoption. Full article
(This article belongs to the Special Issue The 20th Anniversary of IJERPH)
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<p>Flow chart of study.</p>
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21 pages, 4656 KiB  
Article
Assessment of Multiple Citizen Science Methods and Carbon Footprint of Tourists in Two Australian Marine Parks
by Adam K. Smith, Joseph D. DiBattista, Samatha J. Tol, Leona Kustra, Joanne Stacey, Toni Massey and Paul E. Hardisty
Sustainability 2024, 16(24), 11019; https://doi.org/10.3390/su162411019 (registering DOI) - 16 Dec 2024
Viewed by 44
Abstract
Citizen or community science (CS) projects in the marine environment rarely consider carbon footprint and sustainability. In this case study, we assessed the effectiveness of ten CS methods used by tourists in the Great Barrier Reef Marine Park (GBRMP) and Coral Sea Marine [...] Read more.
Citizen or community science (CS) projects in the marine environment rarely consider carbon footprint and sustainability. In this case study, we assessed the effectiveness of ten CS methods used by tourists in the Great Barrier Reef Marine Park (GBRMP) and Coral Sea Marine Park (CSMP) who participated in the 2023 Citizen Science of the Great Barrier Reef expedition and the carbon footprint associated with these field methods. We also assessed the baseline coral reef knowledge of the tourists, observations of marine species, and the communication of our results to the public. Specifically, the tourists utilised up to ten methods: iNaturalist, CoralWatch, Great Barrier Reef Census, Eye on the Reef (EoR), environmental DNA (eDNA) testing kits, photogrammetry, social surveys, and Red Map, as well as marine debris and marine vegetation collections. A total of 10,421 data points were collected across 14 days, including 5390 records (52% of the total) uploaded to iNaturalist, comprising 640 plant and animal species. Public awareness of the CS expedition reached over 700,000 people based on estimates from advertising, media, social media, family and friends, and conference presentations. We estimated the total carbon footprint for the expedition as 268.7 tonnes of CO2 or 4.47 tonnes of CO2 per person, equivalent to AUD 112 needed to offset this input. Based on these results, our recommendations to leverage CS methods include governmental review strategies, temporal replication to allow for the measurement of changes through time, integrating sustainability into CS ecotourism platforms, and encouraging broad participation. Full article
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<p>Map of sampling locations and sites (days) and the boundaries of the Great Barrier Reef Marine Park and Coral Sea Marine Park.</p>
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<p>(<b>a</b>) The Coral Health Chart records changes in coral colour. (<b>b</b>) Demonstration of the two data measurements by citizen scientists record the lightest (E2) and darkest (E5) area within one coral colony. From Coral Watch (2021) Health Chart Do it Yourself instructions.</p>
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<p>Comparison of the number of species uniquely observed in the Great Barrier Reef Marine Park (GBRMP) and the Coral Sea Marine Park (CSMP), as well as those common to both areas.</p>
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<p>(<b>a</b>) The number of observations per taxa and the (<b>b</b>) number of species observed per taxa on the iNaturalist app during the citizen science survey of the Great Barrier Reef Marine Park (GBRMP) and Coral Sea Marine Park (CSMP).</p>
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<p>The number of unique DNA sequences (i.e., Amplified Sequence Variants or ASVs) in the aggregated environmental DNA (eDNA) dataset (N = 876) as a function of taxonomic group and accompanying pie chart displaying the taxonomic rank of those assignments. Numbers in parentheses represent the number of taxa in all cases. ‘Other’ taxonomic ranks included those designated a clade, isolate, tribe, varietas, subspecies, subfamily, superfamily, suborder, subclass, infraclass, or superkingdom.</p>
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<p>Average coral colour distribution in the (<b>a</b>) Great Barrier Reef Marine Park (GBRMP) and the (<b>b</b>) Coral Sea Marine Park (CSMP), as well as coral morphology in the (<b>c</b>) GBRMP and (<b>d</b>) CSMP.</p>
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<p>Observations within 18 categories of animals using the Eye on the Reef survey methodology (i.e., rapid, 10 min surveys) from the Great Barrier Reef Marine Park (GBRMP—green) and Coral Sea Marine Park (CSMP—blue).</p>
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<p>Response to survey question ‘What citizen science tools did you use today?’ when compared between the Great Barrier Reef Marine Park (GBRMP) and Coral Sea Marine Park (CSMP) (N = 129).</p>
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<p>Participants rating of the overall condition of the reef site they visited (<b>top</b>) and their overall satisfaction (<b>bottom</b>).</p>
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16 pages, 677 KiB  
Article
Localization Optimization Algorithm Based on Phase Noise Compensation
by Yanming Liu, Yingkai Cao, Charilaos C. Zarakovitis, Disheng Xiao, Kai Ying and Xianfu Chen
Electronics 2024, 13(24), 4947; https://doi.org/10.3390/electronics13244947 (registering DOI) - 16 Dec 2024
Viewed by 77
Abstract
Phase noise is a consequence of the instability inherent in the operation of oscillators, making it impossible to entirely eliminate. For low-cost internet of things (IoT) devices, this type of noise can be particularly pronounced, posing a challenge in providing high-quality localization services. [...] Read more.
Phase noise is a consequence of the instability inherent in the operation of oscillators, making it impossible to entirely eliminate. For low-cost internet of things (IoT) devices, this type of noise can be particularly pronounced, posing a challenge in providing high-quality localization services. To tackle this issue, this paper introduces an improved localization algorithm that includes phase noise compensation. The proposed algorithm enhances the direction of arrival (DoA) estimation for each base station by employing the EM–MUSIC method, subsequently forming a non-convex optimization problem based on the mean square error (MSE) of the estimated DoA results. Finally, a closed-form solution is derived through rational assumptions and approximations. Results show that this algorithm effectively minimizes localization errors and achieves accuracy levels within the sub-meter range. Full article
(This article belongs to the Special Issue Energy-Efficient Wireless Solutions for 6G/B6G)
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<p>SIMO localization system.</p>
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<p>Phase noise diagram.</p>
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<p>Multiple base stations localization scenario based on triangulation.</p>
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<p>EM–MUSIC algorithm flowchart.</p>
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<p>Multiple base stations optimization algorithm flowchart.</p>
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<p>Effect of phase noise on the performance of MUSIC algorithm.</p>
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<p>The RMSE of different DoA estimation algorithms.</p>
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<p>Layout diagram of eight base stations.</p>
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<p>The variation of mean estimation error with the number of iterations.</p>
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<p>CDF of location error when some base stations receive signals with high noise.</p>
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<p>The relationship between average error and the number of uninterfered base stations.</p>
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<p>Variation of average estimation error with the number of participated base stations.</p>
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<p>Results of 20 single localizations.</p>
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19 pages, 361 KiB  
Article
Neural Network-Based Parameter Estimation in Dynamical Systems
by Dimitris Kastoris, Kostas Giotopoulos and Dimitris Papadopoulos
Information 2024, 15(12), 809; https://doi.org/10.3390/info15120809 (registering DOI) - 16 Dec 2024
Viewed by 84
Abstract
Mathematical models are designed to assist decision-making processes across various scientific fields. These models typically contain numerous parameters, the values’ estimation of which often comes under analysis when evaluating the strength of these models as management tools. Advanced artificial intelligence software has proven [...] Read more.
Mathematical models are designed to assist decision-making processes across various scientific fields. These models typically contain numerous parameters, the values’ estimation of which often comes under analysis when evaluating the strength of these models as management tools. Advanced artificial intelligence software has proven to be highly effective in estimating these parameters. In this research work, we use the Lotka–Volterra model to describe the dynamics of a telecommunication sector in Greece, and then we propose a methodology that employs a feed-forward neural network (NN). The NN is used to estimate the parameter’s values of the Lotka–Volterra system, which are later applied to solve the system using a fourth-algebraic-order Runge–Kutta method. The application of the proposed architecture to the specific case study reveals that the model fits well to the experiential data. Furthermore, the results of our method surpassed the other three methods used for comparison, demonstrating its higher accuracy and effectiveness. The implementation of the proposed feed-forward neural network and the fourth-algebraic-order Runge–Kutta method was accomplished using MATLAB. Full article
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<p>An example of a random feed-forward neural network with one input neuron, three output neurons, and two hidden layers with seven neurons on every layer.</p>
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<p>Neural network estimates and the measured data for the three competitors <span class="html-italic">x</span>, <span class="html-italic">y</span>, and <span class="html-italic">z</span>.</p>
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<p>Comparison of the four methods with the measured data for the <span class="html-italic">x</span> competitor.</p>
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<p>Comparison of the four methods with the measured data for the <span class="html-italic">y</span> competitor.</p>
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<p>Comparison of the four methods with the measured data for the <span class="html-italic">z</span> competitor.</p>
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12 pages, 2712 KiB  
Technical Note
Landslide Thickness Estimated from InSAR-Derived 2D Deformation: Application to the Xiongba Ancient Landslide, China
by Yinghui Yang, Qian Xu, Liyuan Xie, Qiang Xu, Jyr-Ching Hu and Qiang Chen
Remote Sens. 2024, 16(24), 4689; https://doi.org/10.3390/rs16244689 (registering DOI) - 16 Dec 2024
Viewed by 124
Abstract
The thickness estimation of landslides is crucial for better landslide evaluation. Traditional non-contact mass conservation methods using 3D deformation may be unsuitable due to observation limitations. This study proposes a more feasible approach based on 2D deformation from two-track Interferometric Synthetic Aperture Radar [...] Read more.
The thickness estimation of landslides is crucial for better landslide evaluation. Traditional non-contact mass conservation methods using 3D deformation may be unsuitable due to observation limitations. This study proposes a more feasible approach based on 2D deformation from two-track Interferometric Synthetic Aperture Radar (InSAR) observations, applied to the Xiongba landslide. The comparison with geological and drilling measurements confirms the reliability of this method. The mapped InSAR LOS deformation rate fields reveal two regions: a significantly deformed frontal zone and a relatively stable zone. Analysis suggests that surface uplift at the Xiongba-H2 landslide’s front edge results from rock–soil mass pushing in high-deformation areas. The estimated thickness ranges from 10 to 100 m, with an active volume of 6.17 × 107 m3. A thicker region is identified at the front edge along the Jinsha River, posing the potential for further failure. This low-cost, easily implemented approach enhances InSAR’s applicability for landslide analysis and hazard assessment. Full article
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<p>Geological background of the study area: (<b>a</b>) coverage of the used SAR images (black rectangles) and the location of the Xiongba ancient landslide (red star); (<b>b</b>) optical images covering the Xiongba landslide. The black solid line indicates the spatial range of the Xiongba ancient landslide, and the red dashed lines represent two secondary landslides (H1 and H2) of the Xiongba ancient landslide; (<b>c</b>) geological profile along line II’, marked in (<b>b</b>), adapted from the study by Jin [<a href="#B27-remotesensing-16-04689" class="html-bibr">27</a>].</p>
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<p>Ground deformation rates of the Xiongba-H2 landslide derived from the ascending (<b>a</b>) and descending (<b>b</b>) InSAR tracks, and the estimated two-dimensional velocity components along the slope (<b>c</b>) and normal (<b>d</b>) directions. The red dashed lines show the spatial scope of the Xiongba-H2 landslide and the boundary between the deformed zone (Region2) and stable zone (Region1). The black dashed lines divide Region2 into three areas (A, B, C) with distinct deformation rate characteristics. The time-series deformation rates of the chosen points marked by T1 and T2 are shown in <a href="#app1-remotesensing-16-04689" class="html-app">Figure S1</a>. The OK, OT, OI axes indicate the landslide motion coordinate system (details can be found in <a href="#app1-remotesensing-16-04689" class="html-app">Figure S2, Text S1</a>). The red axes in the lower-right corner of the subfigures indicate the directions of the displacements.</p>
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<p>Distribution of the estimated thickness of the Xiongba-H2 landslide with different rheological parameters of 0.5 (<b>a</b>), 0.75 (<b>b</b>), and 1.0 (<b>c</b>), respectively. Regions I, II, and III marked by black dashed lines indicate zones with relatively greater thickness. P-P’ shows the surface trace of the geological profile, which is a segment of the profile I-I’ shown in <a href="#remotesensing-16-04689-f001" class="html-fig">Figure 1</a>c. (<b>d</b>) Model misfit versus the rheological parameter <span class="html-italic">f</span>; the misfit reaches its minimum when the rheological parameter equals 0.75. (<b>e</b>) Detailed distributions of landslide thickness along the P-P’ profile. The black solid line indicates the ground surface of the Xiongba-H2 landslide. The purple, blue, and green dashed lines represent the estimated thickness profiles with rheological parameters of 0.5, 0.75, and 1, respectively. The red dashed line denotes the measured thickness based on drilling and geophysical methods from the study by Jin [<a href="#B27-remotesensing-16-04689" class="html-bibr">27</a>].</p>
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20 pages, 2638 KiB  
Article
Estimating Carbon Emissions of Northeast Brazil Railway System
by Diogo da Fonseca Soares, Sayonara Andrade Eliziário, Josicleda Domiciano Galvíncio and Angel Fermin Ramos-Ridao
Buildings 2024, 14(12), 3986; https://doi.org/10.3390/buildings14123986 (registering DOI) - 16 Dec 2024
Viewed by 133
Abstract
This article addresses the developing of a framework to obtain specific GHG emissions for the railway system and proposes mitigation strategies. To achieve this purpose, a comprehensive life cycle assessment (LCA) method was employed with input data from various sources to analyze the [...] Read more.
This article addresses the developing of a framework to obtain specific GHG emissions for the railway system and proposes mitigation strategies. To achieve this purpose, a comprehensive life cycle assessment (LCA) method was employed with input data from various sources to analyze the contribution of energy consumption and the emissions of the railway system. This paper included gathering data from an infrastructure operation and maintenance for detailed GHG emissions impact. This study also presents a comparative analysis of the GHG emissions in different urban railway transportation systems in Northeast Brazil, providing valuable contextual insights. As a result of the combination of total GHG emissions analysis from the states of the Northeast Brazil railway system, a total of 11,996.11 metric tons of CO2 equivalent (tCO2e) was estimated. The main line traction was a prominent source of the greenhouse gas footprint, especially for the diesel traction systems at Paraiba. The proposed framework shows that significant environmental benefits can be realized with proper decision-making to increase the number of passengers–kilometer transported by rail. Full article
(This article belongs to the Special Issue Urban Climatic Suitability Design and Risk Management)
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<p>Location map of the northeastern railway system, Brazil.</p>
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<p>Flowchart of greenhouse gas emissions methodology for LCA railway.</p>
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<p>Composition of consumption and emissions in 2021.</p>
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<p>Composition of consumption and GHG emissions of rail system. (<b>A</b>) Rail system of Pernambuco. (<b>B</b>) Rail system of Paraiba. (<b>C</b>) Rail system of Alagoas. (<b>D</b>) Rail system of Rio Grande do Norte.</p>
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<p>GHG emissions of main line traction (diesel).</p>
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<p>GHG emission (gCO<sub>2</sub>/PKT).</p>
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14 pages, 298 KiB  
Article
Additional Value of Pertechnetate Scintigraphy to American College of Radiology Thyroid Imaging Reporting and Data Systems and European Thyroid Imaging Reporting and Data Systems for Thyroid Nodule Classification in Euthyroid Patients
by Lea Sollmann, Maria Eveslage, Moritz Fabian Danzer, Michael Schäfers, Barbara Heitplatz, Elke Conrad, Daniel Hescheler, Burkhard Riemann and Benjamin Noto
Cancers 2024, 16(24), 4184; https://doi.org/10.3390/cancers16244184 (registering DOI) - 16 Dec 2024
Viewed by 182
Abstract
Background: Thyroid nodules are common yet remain a diagnostic challenge. While ultrasound and Thyroid Imaging Reporting and Data Systems (TIRADS) are accepted as standard, the use of thyroid scintigraphy in euthyroid patients is debated. The European Association of Nuclear Medicine advocates it, whereas [...] Read more.
Background: Thyroid nodules are common yet remain a diagnostic challenge. While ultrasound and Thyroid Imaging Reporting and Data Systems (TIRADS) are accepted as standard, the use of thyroid scintigraphy in euthyroid patients is debated. The European Association of Nuclear Medicine advocates it, whereas the American Thyroid Association and European Thyroid Association do not. However, it has not been evaluated whether scintigraphy adds value to TIRADS in a multimodal approach. Our study addresses this gap by assessing the impact of integrated pertechnetate scintigraphy on TIRADS accuracy. Methods: The diagnostic performance of ACR-TIRADS, EU-TIRADS, pertechnetate scintigraphy, and multimodal models were retrospectively analyzed for 322 nodules (231 benign, 91 malignant) in 208 euthyroid patients with histopathology as a reference. Generalized estimating equations were used for statistical analysis. Results: On scintigraphy, 210 nodules were hypofunctional, 99 isofunctional, and 13 hyperfunctional. The AUC for thyroid scintigraphy, ACR-TIRADS, and EU-TIRADS were 0.6 (95% CI: 0.55–0.66), 0.83 (95% CI: 0.78–0.88), and 0.78 (95% CI: 0.72–0.83). Integrating scintigraphy with ACR-TIRADS and EU-TIRADS slightly increased diagnostic accuracy (AUC 0.86 vs. 0.83, p = 0.039 and AUC 0.80 vs. 0.78, p = 0.008) and adjusted the malignancy probability for intermediate risk TIRADS categories, with iso- or hyperfunctioning nodules in ACR-TIRADS-TR4 or EU-TIRADS-4 showing comparable malignancy probabilities as hypofunctioning nodules in TR3 or EU-TIRADS-3, respectively. Conclusions: Integrating thyroid scintigraphy with ACR- or EU-TIRADS moderately improves diagnostic performance, potentially benefiting management, especially in complex cases like multinodular goiter or indeterminate FNA. Further research is warranted to validate these findings and explore their clinical implications. Full article
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<p>Mosaic plot illustrating the relationship between nodule status and (<b>A</b>) functional status assessed by scintigraphy, (<b>B</b>) ACR-TIRADS score, (<b>C</b>) ACR-TIRADS category, and (<b>D</b>) EU-TIRADS category. The width of each vertical segment represents the proportion of nodules that are hypofunctional, isofunctional, or hyperfunctional on thyroid scintigraphy (<b>A</b>), and the proportion of nodules in each ACR-TIRADS score (<b>B</b>), ACR-TIRADS category (<b>C</b>), and EU-TIRADS category (<b>D</b>). The height of each colored section corresponds to the proportion of malignant nodules, with full height representing 100%.</p>
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<p>ROC curves for: (<b>A</b>) thyroid scintigraphy (dashed line, AUC: 0.6), ACR-TIRADS score (dotted line, AUC: 0.84), and the combined model (solid line, AUC: 0.86). (<b>B</b>) Thyroid scintigraphy (dashed line, AUC: 0.6), ACR-TIRADS categories (dotted line; AUC: 0.83), and the combined model (solid line, AUC: 0.86).</p>
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<p>ROC curves for: thyroid scintigraphy (dashed line, AUC: 0.6), EU-TIRADS (dotted line; 0.78), and the combined model (solid line, AUC: 0.80).</p>
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<p>Barplot showing the relation of nodule dignity and functional status as assesed by scintigraphy, stratified by ACR-TIRADS category (<span class="html-italic">n</span> = 322 nodules in 208 patients). The proportion of hypofunctioning nodules is higher in malignant nodules in all ACR-TIRADS categories. Note that there are malignant hyperfunctional nodules.</p>
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<p>Barplot showing the relation of nodule dignity and functional status as assessed by scintigraphy, stratified by EU-TIRADS category (<span class="html-italic">n</span> = 322 nodules in 208 patients).</p>
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<p>Estimated probability for nodule malignancy (purple cross) and corresponding 95% confidence intervals (bars, <span class="html-italic">n</span> = 322. (<b>A</b>) Combinations of ACR-TIRADS categories and thyroid scintigraphy. Note that the probability of malignancy for a hyper- or isofunctioning nodule in the category TR4 is comparable to a hypofunctional nodule in the category TR3. The probability of malignancy for a iso-/or hyperfunctioning nodule in the category TR3 is comparable to a hypofunctioning nodule in the category TR2 (Confidence intervals for hyper- or isofunctioning nodules in categories TR1 and TR2 could not be estimated; hence, their error bars are greyed out for visual distinction). (<b>B</b>) Combinations of EU-TIRADS categories and thyroid scintigraphy. Note that the probability of malignancy for a hyper- or isofunctioning nodule in the category EU-TIRADS 4 is comparable to a hypofunctional nodule in the category EU-TIRADS 3 (confidence intervals cannot be estimated for category EU-TIRADS 2; hence, their error bars are greyed out for visual distinction).</p>
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24 pages, 4616 KiB  
Article
Estimating a 3D Human Skeleton from a Single RGB Image by Fusing Predicted Depths from Multiple Virtual Viewpoints
by Wen-Nung Lie and Veasna Vann
Sensors 2024, 24(24), 8017; https://doi.org/10.3390/s24248017 (registering DOI) - 15 Dec 2024
Viewed by 468
Abstract
In computer vision, accurately estimating a 3D human skeleton from a single RGB image remains a challenging task. Inspired by the advantages of multi-view approaches, we propose a method of predicting enhanced 2D skeletons (specifically, predicting the joints’ relative depths) from multiple virtual [...] Read more.
In computer vision, accurately estimating a 3D human skeleton from a single RGB image remains a challenging task. Inspired by the advantages of multi-view approaches, we propose a method of predicting enhanced 2D skeletons (specifically, predicting the joints’ relative depths) from multiple virtual viewpoints based on a single real-view image. By fusing these virtual-viewpoint skeletons, we can then estimate the final 3D human skeleton more accurately. Our network consists of two stages. The first stage is composed of a two-stream network: the Real-Net stream predicts 2D image coordinates and the relative depth for each joint from the real viewpoint, while the Virtual-Net stream estimates the relative depths in virtual viewpoints for the same joints. Our network’s second stage consists of a depth-denoising module, a cropped-to-original coordinate transform (COCT) module, and a fusion module. The goal of the fusion module is to fuse skeleton information from the real and virtual viewpoints so that it can undergo feature embedding, 2D-to-3D lifting, and regression to an accurate 3D skeleton. The experimental results demonstrate that our single-view method can achieve a performance of 45.7 mm on average per-joint position error, which is superior to that achieved in several other prior studies of the same kind and is comparable to that of other sequence-based methods that accept tens of consecutive frames as the input. Full article
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<p>(<b>a</b>) Multi-view geometry; (<b>b</b>) our setup with multiple virtual viewpoints (the blue camera is real, the other <span class="html-italic">N</span> (here, <span class="html-italic">N</span> = 7) cameras are virtual, and the two green cameras are selected after experiments (<a href="#sec4dot2dot1-sensors-24-08017" class="html-sec">Section 4.2.1</a>)); (<b>c</b>) geometry for depth error analysis.</p>
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<p>(<b>a</b>) Multi-view geometry; (<b>b</b>) our setup with multiple virtual viewpoints (the blue camera is real, the other <span class="html-italic">N</span> (here, <span class="html-italic">N</span> = 7) cameras are virtual, and the two green cameras are selected after experiments (<a href="#sec4dot2dot1-sensors-24-08017" class="html-sec">Section 4.2.1</a>)); (<b>c</b>) geometry for depth error analysis.</p>
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<p>(<b>a</b>) Overall architecture of our proposed two-stream method. (<b>b</b>) Detailed architecture of the first-stage network, including the “real” stream (Real-Net) and virtual stream (Virtual-Net). (<b>c</b>) Detailed architecture of the fusion module (FM) in the second stage. <span class="html-italic">N</span> denotes the number of virtual viewpoints, <span class="html-italic">J</span> denotes the number of joints, and <span class="html-italic">D</span> denotes the dimension of the embeddings.</p>
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<p>(<b>a</b>) Overall architecture of our proposed two-stream method. (<b>b</b>) Detailed architecture of the first-stage network, including the “real” stream (Real-Net) and virtual stream (Virtual-Net). (<b>c</b>) Detailed architecture of the fusion module (FM) in the second stage. <span class="html-italic">N</span> denotes the number of virtual viewpoints, <span class="html-italic">J</span> denotes the number of joints, and <span class="html-italic">D</span> denotes the dimension of the embeddings.</p>
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<p>Global context information of humans (P1–P3) with the same 3D pose captured from different viewpoints (with horizontal viewing angles of −α, 0, and β, respectively) by the camera.</p>
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<p>The architecture of the fusion network in the fusion module, where <span class="html-italic">N</span> is the total number of virtual viewpoints: (<b>a</b>) DenseFC network; (<b>b</b>) GCN.</p>
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<p>Illustration of the bone vector connections in our system.</p>
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<p>(<b>a</b>) Error distribution across different actions, where the dotted red line refers to the overall MPJPE value of 45.7 mm; (<b>b</b>) average MPJPE of each joint.</p>
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<p>(<b>a</b>) Error distribution across different actions, where the dotted red line refers to the overall MPJPE value of 45.7 mm; (<b>b</b>) average MPJPE of each joint.</p>
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<p>Visualized results on the Human3.6M dataset: (<b>a</b>) successful predictions; (<b>b</b>) failed predictions on some joints.</p>
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<p>Qualitative results of the in-the-wild scenarios: (<b>a</b>) successful cases; (<b>b</b>) failed cases.</p>
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27 pages, 9031 KiB  
Article
Novel Quinoline- and Naphthalene-Incorporated Hydrazineylidene–Propenamide Analogues as Antidiabetic Agents: Design, Synthesis, and Computational Studies
by Osama Alharbi, Wael H. Alsaedi, Mosa Alsehli, Saif H. Althagafi, Hussam Y. Alharbi, Yazeed M. Asiri, Ramith Ramu and Mohammed Al-Ghorbani
Pharmaceuticals 2024, 17(12), 1692; https://doi.org/10.3390/ph17121692 (registering DOI) - 15 Dec 2024
Viewed by 405
Abstract
Background: Type 2 diabetes has become a significant global health challenge. Numerous drugs have been developed to treat the condition, either as standalone therapies or in combination when glycemic control cannot be achieved with a single medication. As existing treatments often come with [...] Read more.
Background: Type 2 diabetes has become a significant global health challenge. Numerous drugs have been developed to treat the condition, either as standalone therapies or in combination when glycemic control cannot be achieved with a single medication. As existing treatments often come with limitations, there is an increasing focus on creating novel therapeutic agents that offer greater efficacy and fewer side effects to better address this widespread issue. Methods: The methylene derivatives 3a,b were coupled with phenyl/ethyl isothiocyanate in the basic medium, and dimethyl sulfate was subsequently added. Further, 5ad were reacted with the quinoline/naphthalene hydrazides 6a,b. The target compounds 7ag were subjected to the in vitro enzyme inhibition studies on α-glucosidase, α-amylase, and aldose reductase. Results: 7g exerted remarkable inhibitory effects on α-glycosidase [Inhibitory Concentration (IC50): 20.23 ± 1.10 µg/mL] and α-amylase (17.15 ± 0.30 µg/mL), outperforming acarbose (28.12 ± 0.20 µg/mL for α-glycosidase and 25.42 ± 0.10 µg/mL for α-amylase), and exhibited a strong inhibition action on aldose reductase (12.15 ± 0.24 µg/mL), surpassing quercetin (15.45 ± 0.32 µg/mL) and the other tested compounds. In a computational study, 7g demonstrated promising binding affinities (−8.80, −8.91 kcal/mol) with α-glycosidase and α-amylase, compared to acarbose (−10.87, −10.38 kcal/mol) for α-glycosidase and α-amylase. Additionally, 7g had strong binding with aldose reductase (−9.20 kcal/mol) in comparison to quercetin (−9.95 kcal/mol). Molecular dynamics (MDs) simulations demonstrated that 7g remained stable over a 100 ns simulation period, and the binding free energy estimates remained consistent throughout this time. Conclusions: We reported the modification of quinoline and naphthalene rings to hydrazineylidene–propenamides 7ag using various synthetic approaches. 7g emerged as a leading candidate, exhibiting greater inhibition of α-glycosidase, α-amylase, and aldose reductase. These findings underscore their potential as essential molecules for the development of innovative antidiabetic treatments. Full article
(This article belongs to the Section Medicinal Chemistry)
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<p>(<b>a</b>) Function of α-amylase and α-glucosidase. (<b>b</b>) Function of aldose reductase.</p>
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<p>Fundamental pharmacophoric features of the amide linker in antidiabetic drugs.</p>
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<p>Design of the target compound <b>7g</b>.</p>
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<p>Compound <b>7g</b> interacting with active site amino acids of α-glucosidase are represented in two dimensions (<b>A</b>), and acarbose interacting with the active site amino acids of α-glucosidase are represented in two dimensions (<b>B</b>).</p>
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<p>Compound <b>7g</b> interacting with active site amino acids of α-amylase are represented in two dimensions (<b>A</b>), and acarbose interacting with the active site amino acids of α-amylase are represented in two dimensions (<b>B</b>).</p>
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<p>Compound <b>7g</b> interacting with active site amino acids of aldose reductase are represented in two dimensions (<b>A</b>), and acarbose interacting with the active site amino acids of aldose reductase are represented in two dimensions (<b>B</b>).</p>
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<p>(<b>a</b>) The validation of molecular docking by the superimposition of the original and re-docked structures of the co-crystal ligand Zenerastat. Green: original compound from PDB. Red: re-docked compound. (<b>b</b>) The validation of molecular docking by the superimposition of the original and re-docked structures of the co-crystal ligand GLC 601. Pink: original compound from PDB. Brown: re-docked compound.</p>
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<p>Trajectories depicting the different properties—RMSD (Å), the radius of gyration, intra hydrogen bonds, molecular surface area, solvent accessible surface area, and the polar surface area of compound <b>7g</b> when complexed with α-glucosidase.</p>
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<p>MD trajectories of α-glucosidase complexed with compound <b>7g</b> and acarbose. (<b>A</b>) RMSD of α-glucosidase. (<b>B</b>) RMSF of α-glucosidase. (<b>C</b>) RMSD of α-glucosidase–compound <b>7g</b>. (<b>D</b>) RMSF of α-glucosidase. (<b>E</b>) RMSF of compound <b>7g</b>. (<b>F</b>) RMSD of α-glucosidase–acarbose. (<b>G</b>) RMSF of α-glucosidase. (<b>H</b>) RMSF of acarbose. The pink color in Figures (<b>C</b>,<b>F</b>) indicates the RMSD of compound <b>7g</b> and acarbose, and the blue color indicates the protein (α-glucosidase) RMSD. The blue color in Figures (<b>B</b>,<b>D</b>,<b>G</b>) indicates the RMSF of the protein i.e., in this case, it is α-glucosidase. The pink color in Figures (<b>E</b>,<b>H</b>) indicates the RMSF of the compound <b>7g</b> and acarbose respectively. The green color in Figures (<b>D</b>,<b>G</b>) indicates Proteins (amino acid residues) that interact with the ligand, which are marked with green-colored vertical bars.</p>
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<p>Trajectories depicting the different properties—RMSD (Å), the radius of gyration, intra hydrogen bonds, molecular surface area, solvent accessible surface area, and the polar surface area of compound <b>7g</b> when complexed with α-amylase.</p>
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<p>MD trajectories of α-amylase complexed with compound <b>7g</b> and acarbose. (<b>A</b>) RMSD of α-amylase. (<b>B</b>) RMSF of α-amylase. (<b>C</b>) RMSD of α-amylase–compound <b>7g</b>. (<b>D</b>) RMSF of α-amylase (<b>E</b>) RMSF of compound <b>7g</b>; (<b>F</b>) RMSD of α-amylase–acarbose (<b>G</b>) RMSF of α-amylase (<b>H</b>) RMSF of acarbose. The pink color in Figures (<b>C</b>,<b>F</b>) indicates the RMSD of compound <b>7g</b> and acarbose, and the blue color indicates the protein (α-glucosidase) RMSD. The blue color in Figures (<b>B</b>,<b>D</b>,<b>G</b>) indicates the RMSF of the protein i.e., in this case, it is α-glucosidase. The pink color in Figures (<b>E</b>,<b>H</b>) indicates the RMSF of the compound <b>7g</b> and acarbose respectively. The green color in Figures (<b>D</b>,<b>G</b>) indicates Proteins (amino acid residues) that interact with the ligand, which are marked with green-colored vertical bars.</p>
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<p>Trajectories depicting the different properties—RMSD (Å), the radius of gyration, intra hydrogen bonds, molecular surface area, solvent accessible surface area, and the polar surface area of compound <b>7g</b> when complexed with aldose reductase.</p>
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<p>MD trajectories of aldose reductase complexed with compound <b>7g</b> and quercetin. (<b>A</b>) RMSD of aldose reductase. (<b>B</b>) RMSF of aldose reductase. (<b>C</b>) RMSD of aldose reductase–compound <b>7g</b>. (<b>D</b>) RMSF of aldose reductase. (<b>E</b>) RMSF of compound <b>7g</b>. (<b>F</b>) aldose reductase–quercetin RMSD. (<b>G</b>) RMSF of aldose reductase. (<b>H</b>) RMSF of quercetin. The pink color in Figures (<b>C</b>,<b>F</b>) indicates the RMSD of compound <b>7g</b>, and the blue color indicates the protein RMSD. The blue color in Figures (<b>B</b>,<b>D</b>,<b>G</b>) indicates the RMSF of the protein i.e., in this case, it is aldose reductase. The pink color in Figures (<b>E</b>,<b>H</b>) indicates the RMSF of the compound <b>7g</b> and quercetin respectively. The green color in Figure (<b>D</b>) indicates Proteins (amino acid residues) that interact with the ligand, which are marked with green-colored vertical bars.</p>
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<p>ADMET radar analysis of compound <b>7d</b>.</p>
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<p>The initial examination of the SAR of the derivatives <b>5a</b>–<b>g</b>.</p>
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<p>Synthesis of quinoline and naphthalene derivatives <b>7a</b>–<b>g</b>.</p>
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27 pages, 6874 KiB  
Article
Optimization-Assisted Filter for Flow Angle Estimation of SUAV Without Adequate Measurement
by Ziyi Wang, Jie Li, Chang Liu, Yu Yang, Juan Li, Xueyong Wu, Yachao Yang and Bobo Ye
Drones 2024, 8(12), 758; https://doi.org/10.3390/drones8120758 (registering DOI) - 15 Dec 2024
Viewed by 346
Abstract
The accurate estimation of flow angles is crucial for enhancing flight performance and aircraft safety. Flow angles of fixed-wing small unmanned aerial vehicles (SUAVs) are more vulnerable due to their low airspeed. Current flow angle measurement devices have not been widely implemented in [...] Read more.
The accurate estimation of flow angles is crucial for enhancing flight performance and aircraft safety. Flow angles of fixed-wing small unmanned aerial vehicles (SUAVs) are more vulnerable due to their low airspeed. Current flow angle measurement devices have not been widely implemented in SUAVs due to their substantial cost and size constraints. Moreover, there are no general estimation methods suitable for SUAVs based on their rudimentary sensor suite. This study presents a generalized optimization-assisted filter estimation (OAFE) method for estimating the relative velocity and flow angles of fixed-wing SUAVs based on a standard sensor suite. This OAFE method mainly consists of a cubature Kalman filter and an optimizer. The filter serves as the main loop with which to generate flow angles in real time by fusing the acceleration, angular rate, attitude, and airspeed. Without flow angle measurements, the optimizer generates approximate aerodynamic derivatives, which serve as pseudo-measurements with which to refine the performance of the filter. The results demonstrate that the estimated angle of attack and side slip angle displayed root mean square errors of around 0.11° and 0.24° in the simulation. The feasibility was also verified in field tests. The OAFE method does not require flow angle measurements, the prior acquisition of aerodynamic parameters, or model training, making it suitable for quick deployment on different SUAVs. Full article
34 pages, 1292 KiB  
Article
Spatiotemporal Evolution and Obstacle Factor Analysis of Coupling Coordination Between Economic Resilience and Green, Low-Carbon Development in China
by Shujuan Ding and Zhenyu Fan
Sustainability 2024, 16(24), 11006; https://doi.org/10.3390/su162411006 - 15 Dec 2024
Viewed by 388
Abstract
To achieve economic resilience and green, low-carbon development are two goals of China’s high-quality economic development. This paper uses the entropy weight method and coupling coordination degree model to estimate the coupling coordination level of economic resilience and green, low-carbon development. Kernel density [...] Read more.
To achieve economic resilience and green, low-carbon development are two goals of China’s high-quality economic development. This paper uses the entropy weight method and coupling coordination degree model to estimate the coupling coordination level of economic resilience and green, low-carbon development. Kernel density estimation, Moran index, Dagum Gini coefficient, Markov chain, and obstacle degree model are used to explore the spatiotemporal evolution characteristics and obstacle factors. The results are as follows. (1) The coupling coordination degree between China’s economic resilience and green, low-carbon development has increased overall. However, the eastern region has the highest, and the central region has the fastest growth. (2) The coupling coordination degree shows positive spatial autocorrelation, with most provinces exhibiting high–high or low–low aggregation characteristics. (3) The contribution of imbalance mainly comes from inter-regional differences, but the contribution of intra-regional differences to imbalance is increasing. (4) The spatio-temporal evolution pattern is generally better, and the probability of the coupling coordination degree maintaining the initial state is the largest. The neighborhood’s state affects the transition probability but does not affect that of high-level provinces. (5) Innovation capacity is the main obstacle to improving economic resilience, and per capita water resources are the main obstacle to green and low-carbon development. Finally, this paper puts forward suggestions for creating a good innovation environment, increasing R&D investment, promoting green technology progress, optimizing regional cooperation and resource allocation, and promoting industrial green transformation. Full article
(This article belongs to the Special Issue Advanced Studies in Economic Growth, Environment and Sustainability)
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<p>Spatial–temporal evolution of economic resilience. (Note: Detailed results are provided in <a href="#app1-sustainability-16-11006" class="html-app">Appendix A</a> <a href="#sustainability-16-11006-t0A1" class="html-table">Table A1</a>).</p>
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<p>Spatial–temporal evolution of green and low-carbon development. (Note: Detailed results are provided in <a href="#app1-sustainability-16-11006" class="html-app">Appendix A</a> <a href="#sustainability-16-11006-t0A2" class="html-table">Table A2</a>).</p>
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<p>Spatio-temporal evolution trend of coupling coordination degree.</p>
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<p>Kernel density estimation of the coupling coordination degree between China’s economic resilience and green, low-carbon development.</p>
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<p>Kernel density estimation of coupling coordination degree between regional economic resilience and green and low-carbon development.</p>
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<p>Moran scatter plot. (Note: 1 = Shanghai; 2 = Yunnan; 3 = Inner Mongolia; 4 = Beijing; 5 = Jilin; 6 = Sichuan; 7 = Tianjin; 8 = Ningxia; 9 = Anhui; 10 = Shandong; 11 = Shanxi; 12 = Guangdong; 13 = Guangxi; 14 = Xinjiang; 15 = Jiangsu; 16 = Jiangxi; 17 = Hebei; 18 = Henan; 19 = Zhejiang; 20 = Hainan; 21 = Hubei; 22 = Hunan; 23 = Gansu; 24 = Fujian; 25 = Guizhou; 26 = Liaoning; 27 = Chongqing; 28 = Shaanxi; 29 = Qinghai; 30 = Heilongjiang).</p>
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21 pages, 13076 KiB  
Article
A Framework for High-Spatiotemporal-Resolution Soil Moisture Retrieval in China Using Multi-Source Remote Sensing Data
by Zhuangzhuang Feng, Xingming Zheng, Xiaofeng Li, Chunmei Wang, Jinfeng Song, Lei Li, Tianhao Guo and Jia Zheng
Land 2024, 13(12), 2189; https://doi.org/10.3390/land13122189 (registering DOI) - 15 Dec 2024
Viewed by 513
Abstract
High-spatiotemporal-resolution and accurate soil moisture (SM) data are crucial for investigating climate, hydrology, and agriculture. Existing SM products do not yet meet the demands for high spatiotemporal resolution. The objective is to develop and evaluate a retrieval framework to derive SM estimates with [...] Read more.
High-spatiotemporal-resolution and accurate soil moisture (SM) data are crucial for investigating climate, hydrology, and agriculture. Existing SM products do not yet meet the demands for high spatiotemporal resolution. The objective is to develop and evaluate a retrieval framework to derive SM estimates with high spatial (100 m) and temporal (<3 days) resolution that can be used on a national scale in China. Therefore, this study integrates multi-source data, including optical remote sensing (RS) data from Sentinel-2 and Landsat-7/8/9, synthetic aperture radar (SAR) data from Sentinel-1, and auxiliary data. Four machine learning and deep learning algorithms are applied, including Random Forest Regression (RFR), Extreme Gradient Boosting (XGBoost), Long Short-Term Memory (LSTM) networks, and Ensemble Learning (EL). The integrated framework (IF) considers three feature scenarios (SC1: optical RS + auxiliary data, SC2: SAR + auxiliary data, SC3: optical RS + SAR + auxiliary data), encompassing a total of 33 features. The results are as follows: (1) The correlation coefficients (r) between auxiliary data (such as sand fraction, r = −0.48; silt fraction, r = 0.47; and evapotranspiration, r = −0.42), SAR features (such as the backscatter coefficients for VV-pol (σvv0), r = 0.47), and optical RS features (such as Shortwave Infrared Band 2 (SWIR2) reflectance data from Sentinel-2 and Landsat-7/8/9, r = −0.39) with observed SM are significant. This indicates that multi-source data can provide complementary information for SM monitoring. (2) Compared to XGBoost and LSTM, RFR and EL demonstrate superior overall performance and are the preferred models for SM prediction. Their R2 for the training and test sets exceed 0.969 and 0.743, respectively, and their ubRMSE are below 0.022 and 0.063 m3/m3, respectively. (3) The SM prediction accuracy is highest for the scenario of optical + SAR + auxiliary data, followed by SAR + auxiliary data, and finally optical + auxiliary data. (4) With an increasing Normalized Difference Vegetation Index (NDVI) and SM values, the trained models exhibit a general decrease in prediction performance and accuracy. (5) In 2021 and 2022, without considering cloud cover, the IF theoretically achieved an SM revisit time of 1–3 days across 95.01% and 96.53% of China’s area, respectively. However, SC1 was able to achieve a revisit time of 1–3 days over 60.73% of China’s area in 2021 and 69.36% in 2022, while the area covered by SC2 and SC3 at this revisit time accounted for less than 1% of China’s total area. This study validates the effectiveness of combining multi-source RS data with auxiliary data in large-scale SM monitoring and provides new methods for improving SM retrieval accuracy and spatiotemporal coverage. Full article
(This article belongs to the Section Land – Observation and Monitoring)
Show Figures

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Figure 1
<p>The spatial distribution of the SONTE-China 17 sites within the study area.</p>
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<p>A framework for estimating SM based on multi-source RS data. *** represents the first priority, ** represents the second priority, and * represents the third priority.</p>
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<p>The training (<b>top</b>) and test (<b>bottom</b>) results of four models from IF at SONTE-China (17 sites). The red dotted line is the trend line. The gray dotted line represents the error line at 0.06 m<sup>3</sup>/m<sup>3</sup>.</p>
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<p>The training results of four models at SONTE-China (17 sites). The red dotted line is the trend line. The gray dotted line represents the error line at 0.06 m<sup>3</sup>/m<sup>3</sup>.</p>
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<p>The test results of four models at SONTE-China (17 sites). The red dotted line is the trend line. The gray dotted line represents the error line at 0.06 m<sup>3</sup>/m<sup>3</sup>.</p>
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<p>The time series of estimated and observed SM from three scenarios at NQ, JYT, and MQ sites. The blue solid line represents the observed SM at 0–5 cm. The green solid line represents the daily NDVI. The red, green, and purple squares represent the estimated SM for SC1, SC2, and SC3, respectively. The blue bars indicate daily precipitation. The red dashed vertical lines distinguish between the training and test sets.</p>
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<p>Revisit time between SC1, SC2, SC3, and IF for monitoring SM in China (2021). (<b>a</b>) SC1: Optical RS + auxiliary data only; (<b>b</b>) SC2: SAR + auxiliary data only; (<b>c</b>) SC3: optical RS + SAR + auxiliary data; (<b>d</b>) IF: combined SC3, SC2, and SC1 scenarios.</p>
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<p>Revisit time between SC1, SC2, SC3, and IF for monitoring SM in China (2022). (<b>a</b>) SC1: Optical RS + auxiliary data only; (<b>b</b>) SC2: SAR + auxiliary data only; (<b>c</b>) SC3: optical RS + SAR + auxiliary data; (<b>d</b>) IF: combined SC3, SC2, and SC1 scenarios.</p>
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<p>Training (<b>top</b>) and test (<b>bottom</b>) results of three categories using the RFR based on the SC3 dataset at SONTE-China (17 sites). The red dotted line is the trend line. The gray dotted line represents the error line at 0.06 m<sup>3</sup>/m<sup>3</sup>.</p>
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<p>Performance of different models under various NDVI categories in the training set (<b>left</b>) and test set (<b>right</b>). The colored dot lines represent R<sup>2</sup>, and the bar charts represent ubRMSE.</p>
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<p>Performance of different models under various SM categories in the training set (<b>left</b>) and test set (<b>right</b>). The bar charts represent ubRMSE, and the red dot line represents the average ubRMSE.</p>
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<p>Revisit time distribution for multi-source RS monitoring of SM under different scenarios (2021–2022).</p>
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