Search Results (813)

The two-parameter Birnbaum–Saunders (B-S) distribution is widely applied across various fields due to its favorable statistical properties. This study aims to enhance the efficiency of modified moment estimators for the B-S distribution by systematically incorporating auxiliary non-sample information. To this end, we developed and analyzed a suite of estimation strategies, including restricted estimators, preliminary test estimators, and Stein-type shrinkage estimators. A pretest procedure was formulated to guide the decision on whether to integrate the non-sample information. The relative performance of these estimators was rigorously evaluated through an asymptotic distributional analysis, comparing their asymptotic distributional bias and risk under a sequence of local alternatives. The finite-sample properties were assessed via Monte Carlo simulation studies. The practical utility of the proposed methods is demonstrated through applications to two real-world datasets: failure times for mechanical valves and bone mineral density measurements. Both numerical results and theoretical analysis confirm that the proposed shrinkage-based techniques deliver substantial efficiency gains over conventional estimators. Full article

Payments for Ecosystem Services (PESs) have become a central instrument in global biodiversity finance, yet endangered species-specific PESs remain rare and poorly understood in implementation terms. Taiwan provides a revealing case: a three-year program paying farmers to conserve four threatened species—Prionailurus bengalensis, Lutra lutra, Tyto longimembris, and Hydrophasianus chirurgus—in working farmland across Taiwan and Kinmen island. Through semi-structured interviews with farmers, residents, and local conservation actors, we examine how payments are interpreted, rationalized, enacted, and emotionally experienced at the ground level. This study adopts Colaizzi’s data analysis method, the primary advantage of which lies in its ability to systematically transform fragmented and emotive interview narratives into a logically structured essential description. This is achieved through the rigorous extraction of significant statements and the subsequent synthesis of thematic clusters. Participants reported willingness to continue not only because subsidies offset losses, but because rarity, community pride, and the visible arc of “we helped this creature survive” became internalized rewards. NGOs amplified this shift by translating science into farm practice and “normalizing” coexistence. In practice, conservation work became a social project—identifying threats, altering routines, and defending habitat as a shared civic act. This study does not estimate treatment-effect size; instead, it delivers mechanistic insight at a live policy moment, as Taiwan expands PESs and the OECD pushes incentive reform. The finding is simple and strategically important: endangered-species PESs work best where payments trigger meaning—not where payments replace it. Full article

Background: Mechanical loading is a fundamental regulator of bone remodelling; however, the mechanotransduction mechanisms governing alveolar bone adaptation under tensile-dominant orthodontic loading remain insufficiently defined. In particular, the molecular pathways associated with tension-driven cortical modelling in the periodontal ligament (PDL)–bone complex have not been systematically interpreted in the context of advanced biomechanical simulations. Methods: A nonlinear finite element model of the alveolar bone–PDL–tooth complex was developed using patient-specific CBCT data. Three loading configurations were analysed: (i) conventional orthodontic loading, (ii) loading combined with corticotomy alone, and (iii) a translation-dominant configuration generated by the Bone Protection System (BPS). Pressure distribution, displacement vectors, and stress polarity within the PDL and cortical plate were quantified across different bone density conditions. The mechanical outputs were subsequently interpreted in relation to established mechanotransductive molecular pathways involved in osteogenesis and angiogenesis. Results: Conventional loading generated compression-dominant stress fields within the marginal PDL, frequently exceeding physiological thresholds and producing moment-driven root displacement. Corticotomy alone reduced local stiffness but did not substantially alter stress polarity. The BPS configuration redirected loads toward a tensile-favourable mechanical environment characterised by reduced peak compressive pressures and parallel (translation-dominant) displacement vectors. The predicted tensile stress distribution is compatible with activation profiles of key mechanosensitive pathways, including integrin–FAK signalling, Wnt/β-catenin–mediated osteogenic differentiation and HIF-1α/VEGF-driven angiogenic coupling, suggesting a microenvironment that may be more conducive to cortical apposition than to resorption. Conclusions: This study presents a computational–molecular framework linking finite element–derived tensile stress patterns with osteogenic and angiogenic signalling pathways relevant to alveolar bone remodelling. The findings suggestthat controlled redirection of orthodontic loading toward tensile domains may shift the mechanical environment of the PDL–bone complex toward conditions associated with osteogenic than resorptive responses providing a mechanistic basis for tension-induced cortical modelling. This mechanobiological paradigm advances the understanding of load-guided alveolar bone adaptation at both the tissue and molecular levels. Full article

Local scour around suction caisson foundations has emerged as a significant geotechnical hazard for offshore wind turbines as developments extend into deeper waters. This study quantitatively evaluates the scour-induced degradation of the bearing capacity of suction buckets in sand using a three-dimensional finite element model incorporating the Hardening Soil (HS) constitutive model. The HS framework enables realistic representation of stress-dependent stiffness, dilatancy, and plastic hardening, which are essential for simulating stress redistribution caused by scour. Parametric analyses covering a broad range of relative scour depths show that scour depth is the primary factor governing capacity loss. Increasing scour leads to systematic reductions in horizontal and moment capacities, evident stiffness softening, and a downward migration of plastic zones. A critical threshold is identified at S_d/L = 0.3, beyond which the rate of capacity deterioration increases significantly. The H–M failure envelopes contract progressively and exhibit increasing flattening with scour depth while maintaining nearly constant eccentricity. Empirical relationships between scour depth and key envelope parameters are further proposed to support engineering prediction. The results highlight the necessity of integrating scour effects into design and assessment procedures for suction bucket foundations to ensure the long-term performance and safety of offshore wind turbines. Full article

The optimization of low-Reynolds-number airfoils for micro unmanned aerial vehicles (UAVs) is challenging due to strong geometric nonlinearities, tight endurance requirements, and the need to maintain performance across multiple operating conditions. Classical surrogate-assisted optimization (SAO) methods combined with genetic algorithms become increasingly expensive and less reliable when class–shape transformation (CST)-based geometries are coupled with several flight conditions. Although deep learning surrogates have higher expressive power, their use in this context is often limited by insufficient local feature extraction, weak adaptation to changes in operating conditions, and a lack of robustness analysis. In this study, we construct a task-specific convolutional neural network–long short-term memory (CNN–LSTM) surrogate that jointly predicts the power factor, lift, and drag coefficients at three representative operating conditions (cruise, forward flight, and maneuver) for the same CST-parameterized airfoil and integrate it into an Non-dominated Sorting Genetic Algorithm II (NSGA-II)-based three-objective optimization framework. The CNN encoder captures local geometric sensitivities, while the LSTM aggregates dependencies across operating conditions, forming a compact encoder–aggregator tailored to low-Re micro-UAV design. Trained on a computational fluid dynamics (CFD) dataset from a validated SD7032-based pipeline, the proposed surrogate achieves substantially lower prediction errors than several fully connected and single-condition baselines and maintains more favorable error distributions on CST-family parameter-range extrapolation samples (±40%, geometry-valid) under the same CFD setup, while being about three orders of magnitude faster than conventional CFD during inference. When embedded in NSGA-II under thickness and pitching-moment constraints, the surrogate enables efficient exploration of the design space and yields an optimized airfoil that simultaneously improves power factor, reduces drag, and increases lift compared with the baseline SD7032. This work therefore contributes a three-condition surrogate–optimizer workflow and physically interpretable low-Re micro-UAV design insights, rather than introducing a new generic learning or optimization algorithm. Full article

Intermetallic alloys based on A15-type compounds, including cubic Ti₃Sb, attract increasing interest due to their tunable electronic properties and potential for surface-related functional applications. Here, the interaction of nitrogen with Ti₃Sb is systematically investigated using spin-polarized density functional theory within the GGA-PBE approximation. Nitrogen adsorption was analyzed on the Ti₃Sb (111), (100), and (110) surfaces by considering top, bridge, and hollow sites at different surface coverages. Low nitrogen coverage was found to minimize lateral adsorbate interactions, allowing reliable evaluation of single-atom adsorption energies. Among the studied configurations, nitrogen adsorption at the hollow site of the Ti₃Sb (111) surface is energetically most favorable. In addition, partial substitution of Ti or Sb atoms by nitrogen in Ti₃Sb supercells was examined to assess its effect on bulk electronic properties. Nitrogen incorporation leads to pronounced modifications of the electronic band structure, density of states, and local magnetic moments, with a strong dependence on crystallographic direction. The calculated results reveal distinct electronic anisotropies originating from direction-dependent band dispersion and associated effective carrier masses. These findings clarify the role of nitrogen in tailoring both surface and bulk electronic characteristics of Ti₃Sb and provide a theoretical basis for the targeted design of A15-type intermetallic materials for sensing, catalytic, and energy-related applications. Full article

Additive manufacturing (AM) is positioned at a pivotal moment, where its long-promised advantages, e.g., lower cost, reduced environmental burden, and accelerated production, are increasingly tangible yet unevenly realized across industries and regions. This review synthesizes evidence from AM processes for different materials to clarify the technical and economic levers that drive outcomes. Cost performance is shown to depend strongly on design choices, deposition rate, post-processing requirements, and feedstock pricing. Environmental impacts hinge on material production routes, regional energy mix, build utilization, and the extent of material reuse. Lead-time reductions are most significant when components are redesigned for AM, when high-throughput processes are applied to compatible geometries, and when production is geographically localized. Emerging digital tools including machine learning, in situ monitoring, and digital twins are accelerating process stabilization and shortening qualification cycles, while hybrid manufacturing lines demonstrate the value of integrating near-net-shape printing with precision finishing. Drawing from these insights, a pragmatic roadmap is proposed: align parts and supply chains with the most suitable AM processes, decarbonize and streamline feedstock production, and increase system utilization. When these conditions are met, AM can deliver broad, quantifiable improvements in cost efficiency, sustainability, and global adoption. By consolidating fragmented evidence into a unified framework, this review responds to the growing need for clarity as AM moves toward broader industrial deployment. Full article

The study presents a comprehensive analysis of the effects of high temperatures (500 °C and 700 °C) on the microstructure, mechanical properties, and acoustic emission (AE) parameters of cold-drawn prestressing steel. The investigations included mechanical testing, AE signal acquisition, and numerical verification using the finite element method (FEM). It was demonstrated that increasing temperature leads to significant microstructural changes (pearlite spheroidisation, carbide coarsening), resulting in strength degradation and a shift in the failure mechanism from quasi-brittle (initial state) to transitional (500 °C), and finally to ductile (700 °C). For the first time, AE parameters (Counts to Peak and RA-value) were correlated with local axial strains ε₂₂ and von Mises equivalent stress, enabling the identification of the moment of onset load-bearing capacity loss and the determination of critical material damage thresholds. A multi-criteria diagnostic indicator was proposed to assess the condition of prestressing steel after fire exposure. The results confirm the high potential of AE as a non-invasive tool for evaluating the safety of prestressing tendons and cables in reinforced concrete structures subjected to overheating or fire. Full article

Background/Objectives: Traditional medical image analysis methods often suffer from locality bias, limiting their ability to model long-range contextual relationships between spatially distributed anatomical structures. To overcome this challenge, this study proposes SPX-GNN (Superpixel Explainable Graph Neural Network). This novel method reformulates image analysis as a structural graph learning problem, capturing both local anomalies and global topological patterns in a holistic manner. Methods: The proposed framework decomposes images into semantically coherent superpixel regions, converting them into graph nodes that preserve topological relationships. Each node is enriched with a comprehensive feature vector encoding complementary diagnostic clues, including colour (CIELAB), texture (LBP and Haralick), shape (Hu moments), and spatial location. A Graph Neural Network is then employed to learn the relational dependencies between these enriched nodes. The method was rigorously evaluated using 5-fold stratified cross-validation on a public dataset comprising 4200 chest X-ray images. Results: SPX-GNN demonstrated exceptional performance in tuberculosis classification, achieving a mean accuracy of 99.82%, an F1-score of 99.45%, and a ROC-AUC of 100.00%. Furthermore, an integrated Explainable Artificial Intelligence module addresses the black box problem by generating semantic importance maps, which illuminate the decision mechanism and enhance clinical reliability. Conclusions: SPX-GNN offers a novel approach that successfully combines high diagnostic accuracy with methodological transparency. By providing a robust and interpretable workflow, this study presents a promising solution for medical imaging tasks where structural information is critical, paving the way for more reliable clinical decision support systems. Full article

Monitoring land use and land cover (LULC) transformations is essential for understanding socio-ecological dynamics. This study assesses structural shifts in Romania’s landscapes between 1990 and 2018 by integrating algorithmic complexity, fractal analysis, and Grey-Level Co-occurrence Matrix (GLCM) texture analysis. Multi-year maps were used to compute Kolmogorov complexity, fractal measures, and 15 GLCM metrics. The measures were compiled into a unified matrix, and temporal trajectories were explored with principal component analysis and k-means clustering to identify inflection points. Informational complexity and Higuchi 2D decline over time, while homogeneity and angular second moment rise, indicating greater local uniformity. A structural transition around 2006 separates an early heterogeneous regime from a more ordered state; 2012 appears as a turning point when several indices reach extreme values. Strong correlations between fractal and texture measures imply that geometric and radiometric complexity co-evolve, whereas large-scale fractal dimensions remain nearly stable. The multi-index approach provides a replicable framework for identifying critical transitions in LULC. It can support landscape monitoring, and future work should integrate finer temporal data and socio-economic drivers. Full article

In this study, we use a structural demand framework rather than simple correlations between taxes and expenditure to investigate whether local taxes in Korea function as a price mechanism for local public goods. We construct a panel dataset for 226 basic local governments (cities, counties, and autonomous districts) over the period 2000–2017 and estimate local public expenditure equations separately for each group. To capture both long-run relationships and short-run dynamics while addressing nonstationarity and endogeneity, we combine fully modified ordinary least squares, panel error-correction models, and system generalized method of moments. Across these specifications, local tax burdens—especially when measured as the ratio of per capita local tax to total general expenditure—are generally negatively associated with local expenditure. However, we show that this negative association is distinct from the price elasticity of demand implied by the structural model: the relevant elasticities, derived from the estimated coefficients rather than observed directly, remain positive for cities, counties, and districts. The results indicate that, under Korea’s current intergovernmental fiscal arrangements, local taxes do not operate as a conventional price signal that induces residents to demand less of local public goods when tax price increases. These findings suggest that transfer dependence, limited fiscal autonomy, and rigid expenditure responsibilities weaken the price mechanism of local taxes and have important implications for the design of local tax policy and intergovernmental fiscal equalization. Full article

This study presents an experimental evaluation of operational wear in Djp 100 trolleybus contact wires used in the city of Lublin (Poland). The objective was to determine quantitative geometric and mechanical indicators of wear and to propose empirically based replacement criteria. New and long-service wires were examined using 3D scanning, optical profilometry, nanoindentation, and tensile testing. The results show significant changes in the cross-sectional geometry and mechanical performance: the maximum local profile deviation reached ≈2.5 mm, the average cross-sectional area decreased by ≈17%, and the moment of inertia $J_x$ was reduced by ≈30% (from ≈878 mm⁴ to ≈610 mm⁴). Tensile tests revealed a drop in breaking force from ≈37 kN (new wire) to ≈27 kN (used wire). Surface roughness Sa decreased approximately threefold, while nanoindentation showed local near-surface strengthening, with hardness and elastic modulus increasing up to twofold in worn zones. Based on these quantitative changes, combined geometric–mechanical wear indicators were formulated and used to derive practical replacement thresholds for trolleybus contact wires. These findings demonstrate that integrating cross-sectional wear, loss of load-bearing capacity, and local surface property changes provides a consistent and technically justified foundation for maintenance decisions in overhead contact line systems. Full article

Steel moment-resisting frames rely on strength and ductility to perform under seismic loads. Conventional techniques such as reduced beam section (RBS) and reduced web section (RWS) improve ductility by relocating plastic hinges but can suffer from local buckling, fabrication challenges, and costly post-earthquake repairs. This study proposes a sacrificial steel sleeve fuse system for bolted endplate connections, designed to concentrate inelastic deformation within a replaceable sleeve while preserving the primary structural components. Experimental tests included standalone sleeve compression, bolted sleeve assemblies, and T-stub connections with and without sleeves, all validated with finite element models. A parametric study evaluated two sleeve geometries—circular wave (CW) and U-shaped (US)—and compared the sleeve fuse system’s monotonic performance with RWS and standard connections. Results indicate that properly designed sleeve fuses significantly enhance ductility and energy dissipation without compromising initial stiffness or strength, achieving up to 1.8 times the ductility and 25.9% higher energy absorption relative to RWS connections. The findings highlight the sleeve fuse as an innovative, easily replaceable, and resilient solution for seismic applications, offering a practical path for both retrofitting existing frames and designing new structures. Full article

This study investigated how Japanese speakers interpret structurally ambiguous wh-questions, testing whether filler–gap resolution is guided by syntactic resolution based on hierarchical structure or linear locality based on surface word order. We combined behavioral key-press responses with fine-grained eye-tracking data and applied cluster-based permutation analysis to capture the moment-by-moment time course of syntactic interpretation as sentences were processed in real time. Key-press responses revealed a preference for resolving the dependency at the main clause (MC) gap position. Eye-tracking data showed early predictive fixations to the MC picture, followed by shifts to the embedded clause (EC) picture as the embedded event was described. These shifts occurred prior to the appearance of syntactic cues that signal the presence of an EC structure, such as the complementizer -to, and were therefore most likely guided by referential alignment with the linguistic input rather than by syntactic reanalysis. A subsequent return of the gaze to the MC picture occurred when the clause-final question particle -ka became available, confirming the interrogative use of the wh-phrase. Both key-press and eye-tracking data showed that participants did not commit to the first grammatically available EC interpretation but instead waited until clause-final particle information confirmed the interrogative use of the wh-phrase, ultimately favoring the MC interpretation. This pattern supports the view that filler–gap resolution is guided by structural locality rather than linear locality. By using high-resolution temporal data and statistically robust analytic techniques, this study demonstrates that Japanese comprehenders engage in predictive yet structurally cautious parsing. These findings challenge earlier claims that filler–gap resolution in Japanese is primarily driven by linear locality and instead showed a preference for resolving dependencies at the structurally higher MC position, consistent with parsing biases previously observed in English, despite typological differences in word order between the two languages. This preference also reflects sensitivity to language-specific morpho-syntactic cues in Japanese, such as clause-final particles. Full article

A compact LED (light emission diode)-based illumination unit controlled by a microcontroller was developed for recombination-type silicon sensor structures. The system employs an 8 × 8 LED matrix that provides programmable spatial excitation patterns across a 2.2 × 2.2 mm sensor surface. Its operation is based on changes in the silicon surface recombination properties upon analyte interaction, producing photocurrent variations of 10–50 nA depending on the dipole moment. Compared with conventional laser-based systems, the proposed LED illumination significantly reduces cost, complexity, and power consumption while maintaining sufficient optical intensity for reliable photoresponse detection. The embedded controller enables precise timing, synchronization with the photocurrent acquisition unit, and flexible adaptation for various biological fluid analyses. This implementation demonstrates a scalable and cost-efficient alternative to stationary LBIC setups and supports integration into portable or IoT-compatible diagnostic systems. For comparative screening, the LED array was used instead of the focused laser beam typically employed in LBIC (laser beam-induced current) measurements. This paper substantially reduced the peak optical intensity at the sample surface, minimizing local thermal heating critical for enzyme-based or plasma samples sensitive to temperature fluctuations. Photocurrent mapping reveals charge-state modification of recombination centers at the SiOx/Si interface under optical excitation. Further optimization is expected for compact or simplified configurations, particularly those aimed at portable applications and automated physiological monitoring systems. Full article