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Search Results (417)

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31 pages, 7794 KB  
Article
A Probabilistic Linguistic Three-Way Group Consensus Framework Integrating Bayesian Best–Worst Method and Regret Theory for Age-Friendliness Evaluation of Aging Urban Residential Communities
by Zhanyu Zhong, Chang Yang, Cong Chen, Fukang Zhao and Kaixing Tang
Mathematics 2026, 14(13), 2243; https://doi.org/10.3390/math14132243 (registering DOI) - 23 Jun 2026
Viewed by 70
Abstract
Multi-criteria group decision making (MCGDM) under linguistic uncertainty remains a fundamental challenge in applied mathematics, where decision makers seldom assign crisp numerical evaluations and frequently exhibit heterogeneous risk attitudes shaped by behavioural factors. An integrated mathematical framework, hereafter PLR-3WBC (Probabilistic Linguistic Regret-driven Three-Way [...] Read more.
Multi-criteria group decision making (MCGDM) under linguistic uncertainty remains a fundamental challenge in applied mathematics, where decision makers seldom assign crisp numerical evaluations and frequently exhibit heterogeneous risk attitudes shaped by behavioural factors. An integrated mathematical framework, hereafter PLR-3WBC (Probabilistic Linguistic Regret-driven Three-Way Bayesian Consensus), is developed to systematically integrate four methodological components that have each been individually validated in the MCGDM literature: representation of decision information with explicit probability mass on linguistic terms; quantification of decision-maker regret and rejoice psychology under linguistic uncertainty; classification of alternatives into three actionable decision regions rather than a single-valued ranking; and group consensus reaching with credal weight aggregation. Each component has demonstrated its effectiveness in its respective domain; the present framework capitalises on their complementary strengths by embedding them within a single pipeline equipped with formal guarantees, an integration that has not been previously reported. The framework integrates five methodological components: probabilistic linguistic term sets (PLTS) for information representation; the Bayesian best–worst method (BBWM) for credal criterion weighting; a regret–rejoice value function adapted to the linguistic domain for behavioural evaluation; three-way decision (3WD) thresholds derived from a loss-function model for actionable classification; and a distance-based consensus reaching process with feedback mechanism for group convergence. A case study on age-friendliness evaluation of twelve aging urban residential communities under an indicator system of five dimensions and eighteen criteria, with four expert decision makers, demonstrates that PLR-3WBC delivers an actionable three-way classification, recovers a transparent group consensus, and produces rankings broadly consistent with classical TOPSIS, VIKOR, PROMETHEE-II, and BWM-TOPSIS (Spearman rank correlation exceeding 0.97), thereby confirming that the integrated framework preserves the ordinal reliability of these established methods, while additionally delivering three outputs that arise from the methodological integration: an actionable three-way classification enabling discrete budget-aligned decisions, credal weight intervals quantifying the depth of expert agreement on criterion importance, and a behavioural reordering of borderline non-dominated alternatives that reflects the loss-averse psychology of the decision panel and would remain hidden under single-method deployment. Sensitivity analyses with respect to the regret aversion coefficient, the loss function parameters, and the consensus threshold confirm that the qualitative classification is stable across a wide parameter envelope, supporting the practical deployment of PLR-3WBC in age-friendly community renewal programmes. Full article
(This article belongs to the Special Issue Multi-Criteria Decision-Making and Operations Research)
20 pages, 2552 KB  
Article
An Integrated AHP–EWM–SPA Approach for Evaluating Safety Management in Highway Tunnel Construction
by Shuangxing Qi, Hualin Zhang, Xuhui Zhou, Bo Wu and Shixiang Xu
Eng 2026, 7(6), 303; https://doi.org/10.3390/eng7060303 (registering DOI) - 22 Jun 2026
Viewed by 126
Abstract
Safety management evaluation in highway tunnel construction involves significant complexity due to multi-level, multi-indicator, and uncertain characteristics. To address these challenges, this study proposes an integrated evaluation approach combining the Analytic Hierarchy Process (AHP), Entropy Weight Method (EWM), and Set Pair Analysis (SPA). [...] Read more.
Safety management evaluation in highway tunnel construction involves significant complexity due to multi-level, multi-indicator, and uncertain characteristics. To address these challenges, this study proposes an integrated evaluation approach combining the Analytic Hierarchy Process (AHP), Entropy Weight Method (EWM), and Set Pair Analysis (SPA). An evaluation index system is established from the perspective of system defensive capability, encompassing four dimensions—organizational, personnel, material, and information management—with 19 indicators. SPA is employed to quantify the relationships among indicators through identity, discrepancy, and opposition, while a hybrid weighting scheme combines subjective judgments and objective data. A confidence-based identification criterion is further introduced to improve the robustness of classification. The proposed model is applied to a highway tunnel project, and the results show good agreement with observed field conditions. The analysis indicates that the method effectively captures intermediate states and uncertainty in safety management systems while reducing bias associated with single weighting strategies and maximum membership-based decisions. The proposed framework provides a practical and reliable approach for safety management evaluation and supports risk-informed decision-making in tunnel construction. Full article
(This article belongs to the Section Chemical, Civil and Environmental Engineering)
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25 pages, 3822 KB  
Article
Preference-Aware Multimodal Journey Planner: An Optimization Approach for Smart Mobility
by Bia Mandžuka, Krešimir Vidović, Marko Ševrović and Jasmin Ćelić
Smart Cities 2026, 9(6), 103; https://doi.org/10.3390/smartcities9060103 (registering DOI) - 19 Jun 2026
Viewed by 145
Abstract
This paper examines the role of Multimodal Journey Planners (MJPs) as a link between user-oriented personalization and the broader societal goals of sustainable urban mobility. In smart cities, MJPs may serve as digital decision-support tools that connect individual mobility choices with broader sustainability [...] Read more.
This paper examines the role of Multimodal Journey Planners (MJPs) as a link between user-oriented personalization and the broader societal goals of sustainable urban mobility. In smart cities, MJPs may serve as digital decision-support tools that connect individual mobility choices with broader sustainability objectives. Although contemporary journey planners increasingly display multiple criteria, such as travel time, cost, CO2 emissions, and number of transfers, they still generally rely on predefined and non-personalized criterion weights and rarely infer travellers’ actual preferences from observed choices. The paper therefore proposes a transparent methodological proof-of-concept that combines multicriteria decision-making and inverse optimization to discover individual preference weights and enable personalized, preference-aware planning of multimodal routes. The Weighted Sum Method (WSM) is adopted as the basic ranking framework, and the proposed approach is evaluated within a controlled methodological testbed based on multimodal journey scenarios in Vienna. The results indicate that, within the available methodological testbed, the preference-discovery-based model achieved closer in-sample agreement with user-provided route evaluations than the model based on explicitly rated criteria. This was observed in the ranking-agreement analysis, where a more favourable penalty-point ratio was obtained in 19/21 cases (90.5%) and in the numerical error comparison, where lower in-sample reconstruction errors were obtained for 18/21 users (85.71%) across all scenarios. The paper further considers the tension between individual and system-level goals, as well as a conceptual extension toward system-aware re-ranking of alternatives. Within the broader framework of smart mobility, the importance of interoperability and open data is also recognized, with National Access Points (NAPs) for multimodal travel information potentially representing an important precondition for the development of advanced and transparent MJP solutions. Full article
(This article belongs to the Special Issue Smart Mobility: Linking Research, Regulation, Innovation and Practice)
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13 pages, 787 KB  
Article
A Comprehensive Evaluation of Mobility: Validation of the Functional Ambulation and Stair Test in Older Adults
by Anson B. Rosenfeldt, Elizabeth Claire Weyman Heller, Eric Zimmerman, Sara Davidson, John Gardner, Grant Alberts, Benjamin Broz, Jordan Klein, Louie Sutte, Emily Hopkins and Jay L. Alberts
J. Clin. Med. 2026, 15(12), 4782; https://doi.org/10.3390/jcm15124782 - 19 Jun 2026
Viewed by 231
Abstract
Background/Objectives: Falls have devastating consequences for older adults. The Functional Ambulation and Stair Test (FAST) was developed to characterize older adult mobility and eventual fall risk. This project aimed to determine the criterion validity of the FAST assessment by comparing the relationship between [...] Read more.
Background/Objectives: Falls have devastating consequences for older adults. The Functional Ambulation and Stair Test (FAST) was developed to characterize older adult mobility and eventual fall risk. This project aimed to determine the criterion validity of the FAST assessment by comparing the relationship between FAST outcomes and existing gold-standard clinical assessments of mobility and fall risk. A secondary aim was assessing the FAST’s capacity to elicit dual-task effects in older adults. Methods: The FAST is a multi-faceted mobility assessment combining stair navigation, turning and level-ground walking; total time and time spent in each phase are the calculated outcomes. Data from 199 older adults completing the FAST, Berg Balance Scale (BBS), Timed Up and Go (TUG), and Ten Meter Walk Test (10MWT) at comfortable and fast speed were evaluated. Relationships between the FAST and clinical outcomes were evaluated with Spearman’s correlations. The FAST and TUG were assessed under single- and dual-task conditions; linear mixed models evaluated the dual-task effects for overall FAST time and each phase. Results: Spearman’s correlations between the FAST and the BBS, TUG, 10MWT comfortable and 10MWT fast were −0.65, 0.88, −0.79, and −0.83, respectively. Participants experienced an 8.6% and 13.2% dual-task cost in the FAST and TUG, respectively. The greatest dual-task cost during the FAST was in the gait initiation, walking, and wide turn phases. Conclusions: Agreement between the FAST and gold-standard clinical mobility assessments confirms the criterion validity of the FAST. Delineation of mobility phases via the FAST offers insight into specific mobility deficits. Future work is ongoing to evaluate the FAST as a fall risk assessment in older adults. Full article
(This article belongs to the Section Geriatric Medicine)
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28 pages, 4858 KB  
Article
Hopf Bifurcation Characteristics of a Magnetic Liquid Double-Suspension Bearing Rotor System
by Xinwei Wang, Xv Zhang, Hanwen Zhang and Jianhua Zhao
Machines 2026, 14(6), 697; https://doi.org/10.3390/machines14060697 - 17 Jun 2026
Viewed by 242
Abstract
To reveal the nonlinear instability mechanism by which the three-degree-of-freedom rotor system of a magnetic-liquid double suspension bearing transforms from stable suspension to periodic vibration, a nonlinear dynamic model considering electromagnetic suspension force, hydrostatic supporting force, rotor unbalance force, and liquid film resistance [...] Read more.
To reveal the nonlinear instability mechanism by which the three-degree-of-freedom rotor system of a magnetic-liquid double suspension bearing transforms from stable suspension to periodic vibration, a nonlinear dynamic model considering electromagnetic suspension force, hydrostatic supporting force, rotor unbalance force, and liquid film resistance is established. The equilibrium point of the system is linearized, and the Hopf bifurcation boundary is determined using the Routh–Hurwitz criterion. Numerical simulations are then carried out to investigate the effects of the initial current i0, supply flow rate q0, and different initial disturbances on the displacement time histories, phase trajectories, and spatial phase trajectories of the rotor. The results show that, under the given system parameters, the Hopf bifurcation boundary is 0.61 A for the initial current and 9.62 × 10−5 m3/s for the supply flow rate. Current variation mainly affects electromagnetic stiffness and nonlinear electromagnetic force, whereas flow rate variation primarily changes the hydrostatic load capacity and oil film damping characteristics. Under different initial disturbances, the system may exhibit amplitude attenuation, recovery to stable suspension, or finite amplitude periodic vibration. Experimental results show good agreement with numerical simulations in terms of frequency spectra, displacement time histories, and phase trajectories, thereby verifying the effectiveness of the proposed three-degree-of-freedom dynamic model and Hopf bifurcation analysis method. The results can provide theoretical guidance for parameter matching, stability evaluation, and self-excited vibration suppression of magnetic-liquid double suspension bearings. Full article
(This article belongs to the Section Electrical Machines and Drives)
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17 pages, 418 KB  
Article
Evaluating the Reliability and Agreement of Rubric-Guided LLM Scoring Versus Human Grading Across Three University Courses
by Howard Kim, Sung-Tae Lee and Jongwon Lee
Appl. Sci. 2026, 16(12), 5902; https://doi.org/10.3390/app16125902 - 11 Jun 2026
Viewed by 157
Abstract
Grading open-ended student work consistently remains a persistent challenge in higher education, and the recent rise of large language models (LLMs) has renewed interest in rubric-guided automated scoring. However, a key gap remains: most studies report correlation rather than agreement, rarely benchmark models [...] Read more.
Grading open-ended student work consistently remains a persistent challenge in higher education, and the recent rise of large language models (LLMs) has renewed interest in rubric-guided automated scoring. However, a key gap remains: most studies report correlation rather than agreement, rarely benchmark models against a local human–human baseline, and seldom test whether simple post hoc calibration improves operational fit. This study addresses that gap by examining whether a rubric-guided LLM can approximate local human grading practice for text-based responses in three university courses, using agreement-oriented rather than correlation-only evidence. A total of 930 student responses from Prompt Engineering, Photoshop Design, and AI Video Production were scored by two human raters and by ChatGPT using the same five-criterion analytic rubric (Accuracy, Logical Flow, Specificity, Quality, and Originality; 0.0–3.0 each; Total 0–15). Human consensus (HC) was defined as the mean of the two human scores and was treated as a pragmatic reference rather than a ground truth. Pairwise agreement among H1, H2, AI, and HC was evaluated using ICC(3,1), Pearson correlations, mean absolute error (MAE), Bland–Altman bias and limits of agreement (LoA); a course-specific held-out calibration analysis was additionally conducted. For the Total score, human–human agreement was strong (ICC = 0.819 [0.797, 0.839]). AI–H1 and AI–H2 Total-score agreement were ICC = 0.700 [0.666, 0.732] and 0.767 [0.739, 0.792], respectively, while AI–HC agreement was ICC = 0.763 [0.735, 0.789], with MAE = 1.603 and LoA = [−4.246, 4.045]. At the trait level, AI–HC ICCs exceeded H1–H2 ICCs for all five rubric dimensions, although Quality remained weakly defined in the human baseline. On a 70/30 held-out test split, a course-specific linear calibration modestly improved Total-score ICC from 0.774 to 0.782 and reduced MAE from 1.624 to 1.215, narrowing the LoA from [−4.290, 4.188] to [−3.157, 3.329]. However, threshold-adjacent agreement remained imperfect after calibration. The principal contribution is a conservative, multi-metric agreement benchmark of rubric-guided LLM scoring against a local human baseline, together with a held-out calibration test that informs deployment. The findings concern written responses only and support a conservative conclusion: rubric-guided LLM scoring can assist human grading under fixed local rubrics, but the current evidence supports calibrated human–AI co-grading rather than unsupervised replacement. Full article
(This article belongs to the Special Issue Generative Artificial Intelligence (AI) in Education)
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29 pages, 17408 KB  
Article
Responsive Architecture in Practice: BIM/DT/AI/IoT for Dynamic Fire Evacuation—A Comparative Case Study Analysis
by Przemysław Konopski, Wojciech Bonenberg, Anna Szymczak-Graczyk, Barbara Ksit and Roman Pilch
Sustainability 2026, 18(12), 5920; https://doi.org/10.3390/su18125920 - 9 Jun 2026
Viewed by 408
Abstract
This study presents a comparative analysis of six DFS implementations representing different maturity levels and investigates the systemic gap between technological capabilities and regulatory approaches. A structured narrative review with case-based analysis was conducted using the Scopus database (2015–2026) with six targeted queries. [...] Read more.
This study presents a comparative analysis of six DFS implementations representing different maturity levels and investigates the systemic gap between technological capabilities and regulatory approaches. A structured narrative review with case-based analysis was conducted using the Scopus database (2015–2026) with six targeted queries. The case selection followed the PICo protocol. An original ten-criterion DFS maturity assessment rubric—grounded in the Technology Readiness Level (TRL), Integration Readiness Level (IRL), and Digital Twin Maturity Model frameworks—was applied to all six cases. Inter-rater validation yielded substantial agreement (κw = 0.797; unweighted κ = 0.674 [95% CI: 0.509, 0.839]). The results indicate a clear maturity gradient (Dimension X: 4–9 points; Dimension Y: 2–8 points). Benefits reported in the analysed primary studies include up to a 55 s reduction in evacuation time, a 72% improvement compared with static signage, and a 34-percentage-point increase in evacuation success rate under simulation-based conditions. Five normative recommendations are proposed to address the structural regulatory gap between current prescriptive frameworks and DFS deployment in Poland and the EU. This study argues that prescriptive rules should remain the baseline, whereas complex facilities may adopt performance-based DFS solutions, provided that equivalence to conventional protection levels is rigorously demonstrated. From a sustainability perspective, the study frames DFS as a dynamic safety layer that supports occupant protection, operational resilience, and lifecycle adaptability in complex buildings exposed to uncertain fire and crowd conditions. Full article
(This article belongs to the Section Green Building)
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13 pages, 1024 KB  
Article
Estimation of Intradialytic Blood Volume Reduction Using Hemoglobin Changes: A Prospective Validation Study of a Pragmatic Clinical Tool
by Nomy Levin Iaina, Muhamed Osman, Fadi Garzuzi, Sergey Bellov and Arie Feldman
J. Clin. Med. 2026, 15(11), 4323; https://doi.org/10.3390/jcm15114323 - 3 Jun 2026
Viewed by 233
Abstract
Background/Objectives: Accurate assessment of intradialytic blood volume (BV) changes is important for optimizing fluid management in hemodialysis, but continuous BV monitoring is not universally available. Hemoglobin changes reflect hemoconcentration and may provide a simple surrogate for estimating BV reduction. We prospectively evaluated a [...] Read more.
Background/Objectives: Accurate assessment of intradialytic blood volume (BV) changes is important for optimizing fluid management in hemodialysis, but continuous BV monitoring is not universally available. Hemoglobin changes reflect hemoconcentration and may provide a simple surrogate for estimating BV reduction. We prospectively evaluated a hemoglobin-based method for estimating intradialytic BV reduction compared with machine-based BV monitoring. Methods: In this prospective single-center observational study, 187 hemodialysis sessions with complete paired measurements were analyzed. Formula-based BV reduction was calculated from pre- and post-dialysis hemoglobin values and compared with machine-measured BV reduction. Agreement was assessed using Pearson correlation, predefined absolute-difference thresholds, and Bland–Altman analysis. Exploratory receiver operating characteristic analyses evaluated the ability of formula-based estimates to identify sessions with larger machine-measured BV reductions. Results: Formula-based and machine-measured BV reduction demonstrated a moderate-to-strong correlation (r = 0.645). The predefined pragmatic agreement criterion of ≥70% of measurements within ±5% was met, with 77.5% of measurements within this range. Bland–Altman analysis demonstrated a small mean bias of −1.5%, with 95% limits of agreement from −12.4% to 9.3%. Exploratory classification performance was favorable across machine-defined BV reduction thresholds, with area under curve (AUC) values ranging from 0.84 to 0.87. At the ≥8% threshold, sensitivity was 72%, specificity 85%, positive predictive value 83%, and negative predictive value 74%. Linear regression showed that 42% of variability in machine-measured BV reduction was explained by the formula-based estimate. Conclusions: A hemoglobin-based approach provides a simple approximation of intradialytic BV reduction. Although not interchangeable with continuous monitoring, it may support post-session assessment and longitudinal evaluation of intradialytic hemodynamic tolerance. Full article
(This article belongs to the Special Issue Peritoneal Dialysis and Hemodialysis: Early and Late Outcomes)
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25 pages, 14903 KB  
Article
A Novel Methodology in Analyzing the Bifurcation, Controller, and Stability of Nonlinear Jet Engine Vibration
by Ahmad Almutlg, Galal M. Moatimid, Tarek S. Amer, Ashraf Taha EL-Sayed, Gamal M. Ismail and Yomna Y. Ellabban
Mathematics 2026, 14(11), 1951; https://doi.org/10.3390/math14111951 - 2 Jun 2026
Viewed by 205
Abstract
Studying jet engine vibration (JEV) enhances flight safety and operational reliability through advanced detection, precision modeling, and data-driven techniques. This approach involves complex nonlinear vibration behaviors that often exceed the capabilities of conventional techniques. It facilitates early fault detection, predictive maintenance, and improved [...] Read more.
Studying jet engine vibration (JEV) enhances flight safety and operational reliability through advanced detection, precision modeling, and data-driven techniques. This approach involves complex nonlinear vibration behaviors that often exceed the capabilities of conventional techniques. It facilitates early fault detection, predictive maintenance, and improved engine design. This study employs the non-perturbative approach (NPA) to examine the dynamics of a parametric nonlinear oscillatory system. The formulation is based on He’s frequency formula (HFF), which transforms a nonlinear ordinary differential equation (ODE) into an equivalent linear one. The analytical results are validated using Mathematica software (MS) (v13), showing strong agreement between the original nonlinear ODE and the corresponding linearized equation. To further explore the system behavior, bifurcation diagrams (BDs) are constructed, and the largest Lyapunov exponent (LLE) is utilized to identify stability regions and detect chaotic oscillations. The averaging method is applied to determine the critical resonance conditions and derive the frequency–response relationships; meanwhile, stability near simultaneous primary resonance is examined using the Routh–Hurwitz criterion. Finally, numerical simulations (NSs) based on the fourth-order Runge–Kutta method (RK-4) confirm the effectiveness of the positive position feedback (PPF) control strategy. Full article
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15 pages, 581 KB  
Article
Agreement Between Novice Visual Assessment and Classifications Derived from Markerless Motion Capture During Sit-to-Stand Performance in Healthy Adults
by Christopher Voltmer and Casey Imperio
Healthcare 2026, 14(11), 1549; https://doi.org/10.3390/healthcare14111549 - 2 Jun 2026
Viewed by 252
Abstract
Background: Visual assessment is commonly used in rehabilitation to evaluate movement quality during functional tasks such as sit-to-stand (STS) transfers. However, the extent to which observational ratings align with classifications derived from portable markerless motion capture systems remains unclear. This study examined agreement [...] Read more.
Background: Visual assessment is commonly used in rehabilitation to evaluate movement quality during functional tasks such as sit-to-stand (STS) transfers. However, the extent to which observational ratings align with classifications derived from portable markerless motion capture systems remains unclear. This study examined agreement between novice observational ratings and motion-capture-derived classifications during STS performance. Methods: Fifty healthy adults performed STS transfers across three 18-inch seating conditions (firm, compliant, commode). Two final-year Doctor of Physical Therapy (DPT) students independently rated movement performance using a standardized observational rubric. Simultaneously, a portable markerless motion capture system (Kinotek) recorded joint kinematics, which were converted into ordinal severity classifications to enable a comparison. Inter-rater reliability and agreement were assessed using percent agreement and Krippendorff’s alpha. Results: Exact agreement between novice raters was high across all surfaces (82.3–82.9%), while Krippendorff’s alpha values were low despite high exact agreement (α = 0.250–0.323), consistent with restricted scale use. Agreement between observational ratings and motion-capture-derived classifications was low, with negative alpha values across all conditions (α = −0.224 to −0.561), indicating systematic differences in classification patterns. Observational raters more frequently assigned lower severity categories compared to motion-capture-derived classifications. Conclusions: Findings demonstrate low chance-corrected agreement under conditions of restricted scale use among novice raters and systematic disagreement between observational and motion-capture-derived classifications during STS performance. These findings reflect differences in classification approaches under the operational definitions used in this study. Motion capture was used as an objective comparator rather than a gold standard, and this study does not establish criterion validity. Further research is needed to evaluate agreement patterns in clinical populations and to examine how different measurement approaches influence functional movement classification. Full article
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15 pages, 1151 KB  
Article
A Speed-Dependent Assessment of E-Textile-Based Sensor Technology: Validity of the Prevayl Wearable Heart Rate Monitor
by Louise C. Burgess, Matthew Armstrong, Louise Beresford and Andrew J. Callaway
Sensors 2026, 26(11), 3378; https://doi.org/10.3390/s26113378 - 26 May 2026
Viewed by 395
Abstract
Background: The use of wearable sensors to measure and monitor heart rate has exponentially grown in recent years, representing an inexpensive, time-efficient, and non-invasive method to assess the status of cardiovascular fitness and the autonomic nervous system. Validating new devices against a criterion [...] Read more.
Background: The use of wearable sensors to measure and monitor heart rate has exponentially grown in recent years, representing an inexpensive, time-efficient, and non-invasive method to assess the status of cardiovascular fitness and the autonomic nervous system. Validating new devices against a criterion standard, such as electrocardiography (ECG), is essential to ensure their accuracy and reliability. This study examined the accuracy and validity of the Prevayl heart rate monitor against 3-lead ECG. Methods: Twenty-six healthy adults (15 female, mean age 32.0 ± 10.4 years) completed a 16-min, incremental running test on a treadmill. Heart rate data were recorded simultaneously throughout the test via ECG and the Prevayl wearable and compared retrospectively. Beat count error (%), mean heart rate absolute error (beats per minute (bpm)), and percentage error (bpm) were calculated. In addition, a Bland–Altman analysis and Pearson’s correlation coefficient were conducted to assess agreement and correlation, respectively. Results: The Prevayl device demonstrated a median beat count agreement of 100.5% with ECG (range: 98.6–104.4%; Npart = 26). Strong correlations were observed between ECG and Prevayl for both raw beat count (r = 0.94, p < 0.01) and heart rate (beats per minute (bpm)) from ECG and the Prevayl algorithm (r = 0.96, p < 0.01). Across running speeds (0–12 kph), a strong correlation was found between raw beat count from ECG and Prevayl (r = 0.82–0.89, p < 0.01) and between bpm from ECG and Prevayl (r = 0.86–0.93, p < 0.01). Bland–Altman plots demonstrated negligible systematic bias. Conclusions: The Prevayl system provides valid measurements when compared to ECG during incremental running. This is demonstrated through strong correlations to ECG heart rate data at different speeds and with different analysis methods, supporting its use for monitoring cardiovascular responses during exercise. Full article
(This article belongs to the Special Issue Wearable Biomedical Sensors for Mobile Health)
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31 pages, 9964 KB  
Article
An Analytical Solution for Tunneling via Virtual Cylinder Model
by Junjie Wei, Yingyi Wang, Xingchun Huang and Lingyu Liu
Appl. Sci. 2026, 16(11), 5193; https://doi.org/10.3390/app16115193 - 22 May 2026
Viewed by 203
Abstract
Deriving rigorous elastoplastic analytical solutions for shallow tunnels subject to a gravity-induced stress gradient presents significant mathematical challenges. This paper introduces a virtual cylindrical structure model to derive a closed-form elastoplastic solution for tunnel excavation. By evaluating the static equilibrium of infinitesimal elements, [...] Read more.
Deriving rigorous elastoplastic analytical solutions for shallow tunnels subject to a gravity-induced stress gradient presents significant mathematical challenges. This paper introduces a virtual cylindrical structure model to derive a closed-form elastoplastic solution for tunnel excavation. By evaluating the static equilibrium of infinitesimal elements, the methodology explicitly determines the plastic zone boundary via the Lambert W function and yields the elastoplastic distributions of stress and displacement fields under the Mohr–Coulomb criterion. The reliability of the derivations is verified by degenerating the equations under specific boundary conditions and comparing them with classical Lamé solutions, showing agreement at low friction angles (ϕ=5°10°). A case study of a 14.5 m-diameter shield tunnel in the Yangtze River Delta is conducted to demonstrate its practical application. The analytical results show that the maximum convergence displacement is controlled within 15 mm, and a ground loss rate of 1.82% corresponds to an unloading ratio of 40%. The proposed method provides a theoretical tool for preliminary estimating excavation-induced disturbances in shallow homogeneous strata. Full article
(This article belongs to the Section Civil Engineering)
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23 pages, 2981 KB  
Article
Application of Dang Van Model Based on Critical Plane Approach for Rolling Contact Problems
by Paweł J. Romanowicz
Materials 2026, 19(10), 2173; https://doi.org/10.3390/ma19102173 - 21 May 2026
Viewed by 229
Abstract
Analyses of rolling contact fatigue (RCF) problems require the use of multiaxial fatigue criteria, which take into account complex non-proportional stress conditions. One of the most often used criteria to analyse this phenomenon is the Dang Van criterion. However, this criterion is often [...] Read more.
Analyses of rolling contact fatigue (RCF) problems require the use of multiaxial fatigue criteria, which take into account complex non-proportional stress conditions. One of the most often used criteria to analyse this phenomenon is the Dang Van criterion. However, this criterion is often criticised due to its overestimation of the influence of compressive stresses on fatigue strength, which leads to an underestimation of the equivalent fatigue stress. Due to the high popularity of this hypothesis, in this paper a few modifications of the Dang Van criterion based on the critical plane approach are compared. One of the investigated modifications is a new proposal in which it is assumed that compressive hydrostatic stresses are as unfavourable as tensile stresses. All variants are verified in three ways: (1) by means of the experimental results for the out-of-phase pulsating compression and alternating torsion; (2) by comparison with the results obtained by means of the Papadopoulos criterion (which provides the most accurate results for RCF issues); and (3) using the example of an RCF analysis of a roller bearing. Based on these investigations, it is confirmed that the original Dang Van criterion is not suitable for application to RCF problems. It is shown that the mere omission of compressive hydrostatic stresses is also insufficient. The highest agreement with the experimental results (relative error δ = 0.77%), the Papadopoulos criterion (δ=5.8%) and, in the case of the practical application (roller bearing; δ=1.1%), is obtained for the proposed modification in which it is assumed that the compressive hydrostatic stress is an unfavourable for fatigue processes in the same way as the tensile hydrostatic stress. Full article
(This article belongs to the Section Mechanics of Materials)
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16 pages, 34018 KB  
Article
On Some Incommensurate Fractional-Order Reaction–Diffusion Systems: The Degn–Harrison and Its Stability
by Omar Kahouli, Amel Hioual, Adel Ouannas, Waleed Mohammed Abdelfattah, Younès Bahou, Ilyes Abidi, Sameir Hamed, Mohamed Chaabane and Sarra Elgharbi
Symmetry 2026, 18(5), 862; https://doi.org/10.3390/sym18050862 - 19 May 2026
Viewed by 187
Abstract
In this paper, we consider a reaction–diffusion system governed by incommensurate fractional time derivatives based on the Degn–Harrison model. Its formulation incorporates various memory effects on axial position through Caputo derivatives of variable orders, producing a more realistic modeling of the temporal dynamics. [...] Read more.
In this paper, we consider a reaction–diffusion system governed by incommensurate fractional time derivatives based on the Degn–Harrison model. Its formulation incorporates various memory effects on axial position through Caputo derivatives of variable orders, producing a more realistic modeling of the temporal dynamics. This paper starts with a study of the spatially homogeneous system and establishes conditions for local stability by using the Matignon criterion. The spectral decomposition method under Neumann boundary condition is then applied to study the complete reaction–diffusion system and describe diffusion-induced instabilities. Our results indicate that the noninteger fractional orders lead to significant changes in stability regions, as well as the initiation of pattern formation. Specifically, the orders of fractions induced as a control variable are regarded to be effective in controlling the stability of the system, thus they are global (or positive) control variables when their values achieved at some levels apply to the entire saturation, etc. Our numerical simulations are in excellent agreement with the theoretical predictions and show that memory asymmetry induces complex spatiotemporal dynamics not seen for classical integer-order systems. Full article
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22 pages, 2872 KB  
Article
Load Capacity Evaluation of ECC and GFRP Strengthened RC Beams Under Combined Bending and Shear
by Jagadesh Kannan Selvan, Preethy Mary Arulanandam, Sherine Stanly and Madappa V. R. Sivasubramanian
J. Compos. Sci. 2026, 10(5), 276; https://doi.org/10.3390/jcs10050276 - 19 May 2026
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Abstract
This study presents a mechanics based analytical framework for predicting the flexural–shear capacity of reinforced concrete (RC) beams strengthened with Engineered Cementitious Composites (ECCs) and a hybrid ECC–GFRP near surface mounted (NSM) system. Building upon previously reported experimental observations, the present work aims [...] Read more.
This study presents a mechanics based analytical framework for predicting the flexural–shear capacity of reinforced concrete (RC) beams strengthened with Engineered Cementitious Composites (ECCs) and a hybrid ECC–GFRP near surface mounted (NSM) system. Building upon previously reported experimental observations, the present work aims to establish rational prediction models capable of capturing the interaction between flexural and shear mechanisms in strengthened beams. The analytical approach integrates sectional analysis for flexural capacity with a modified truss analogy for shear resistance, explicitly incorporating the strain hardening tensile contribution of ECC and the tensile and confinement effects of GFRP reinforcement. An interaction based failure criterion is subsequently employed to identify the governing failure mode under combined flexural shear actions. The proposed model is validated against experimental results obtained from twenty seven beam specimens with varying flexural and shear reinforcement ratios and strengthening configurations. The predicted ultimate loads show good agreement with experimental values, with an average deviation within ±10%. The analytical framework accurately captures the transition between flexural dominated, combined flexural–shear, and diagonal tension failures observed experimentally. Results demonstrate that ECC significantly enhances ductility and shear crack control, while the hybrid ECC–GFRP system provides substantial strength enhancement with a controlled shift in failure mode. Overall, the developed analytical models offer a reliable and computationally efficient tool for predicting the flexural–shear capacity and failure behavior of ECC and hybrid ECC–GFRP-strengthened RC beams, supporting performance based design and practical strengthening applications. Full article
(This article belongs to the Special Issue Polymer Composites and Fibers, 4th Edition)
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