Search Results (9,166)

In large-scale dam construction, the efficiency of concrete transport operations is fundamentally governed by the coordination between horizontal hauling and vertical hoisting capacities. Traditional experience-based scheduling approaches often fail to capture the stochastic, cyclic, and resource-coupled nature of these transport systems. This study developed a closed queuing network-based stochastic simulation framework to model dam concrete transportation as a finite-population cyclic service system. The process was abstracted into sequential service stages with stochastic service times, and a structured state-space representation combined with time-step simulation was constructed to describe dynamic resource occupation and task transitions under varying truck and cable crane configurations. Application to a real large-scale dam project revealed a characteristic multi-stage performance evolution pattern governed by capacity matching mechanisms. As the truck fleet size increased, system performance transitioned from a transport-limited regime to a capacity-coordination regime and ultimately to a hoisting-saturated regime in which further fleet expansion yielded diminishing returns. Sensitivity analysis demonstrated that hoisting capacity imposed an upper bound on system throughput, while adaptive fleet reconfiguration could restore operational equilibrium under constrained equipment availability. The results indicated that dam concrete transport should be treated as a dynamic capacity regulation problem rather than a static allocation task. The proposed framework provides an interpretable and quantitative decision-support tool for equipment configuration, bottleneck identification, and adaptive scheduling in large-scale hydraulic infrastructure projects. Full article

Intelligence metrics based on benchmark performance or population norms are useful for measuring comparative ability within defined test environments, but they do not directly evaluate the structural coherence of an agent’s trajectory across time, domains, and perturbations. This article introduces Reflexive Signature Intelligence (RSI) as a bounded theoretical framework for addressing that different problem. RSI is developed within a causal-symmetric informational perspective in which intelligence is understood as the capacity of a system to maintain and restore alignment with a structurally constrained invariant without collapsing the open gradient of development. On this basis, the paper formulates the Principle of Bounded Subjectivity and the Prohibition of Finality as framework-level principles, arguing that intelligence should be assessed not as arrival at a completed end state but as the quality of an asymptotic trajectory. The framework is then operationalized on two coupled levels: a micro-level proposed as a future measurement program linked heuristically to resilience and prediction-error dynamics, and a macro-level expressed through five dimensions of structural integrity, including reflexive regulation, cross-domain integration, internal consistency, stabilization, and signature-setting. The article concludes by outlining implications for AI evaluation and alignment, with particular relevance for distinguishing full agents, partial systems, and human–AI composite configurations. Full article

Robust controller tuning is essential for the accurate regulation of nonlinear dynamic plants operating under variable conditions. This study proposes an enhanced gradient-based optimizer, termed the quadratic wavelet–enhanced gradient-based optimizer (QWS–GBO), which integrates quadratic interpolation mutation (QIM) and a wavelet mutation strategy (WMS). QIM reinforces population diversity, while WMS mitigates stagnation and strengthens local refinement through adaptive perturbations, yielding a more effective balance between global exploration and local exploitation. QWS–GBO is employed in a reference–follower control framework based on Bode’s ideal response, where the follower is realized by a fractional-order proportional–integral–derivative (FOPID) controller. The FOPID parameters are optimized using QWS–GBO and evaluated in two stages. First, performance is assessed on the CEC2020 benchmark suite under a uniform protocol. Second, the approach is applied to DC motor speed regulation. On the CEC2020 functions, QWS–GBO consistently achieves lower mean objective values and faster convergence than GBO, dwarf mongoose optimization (DMO), the arithmetic optimization algorithm (AOA), and the salp swarm algorithm (SSA) with only minor computational overhead (35.90 s per trial versus 34.00 s for GBO). In the DC motor case, the QWS–GBO–tuned FOPID controller attains a rise time of 0.0216 s, settling time of 0.0350 s, zero overshoot, and peak time of 0.0509 s. Robustness tests under four operating conditions showed limited deviations (maximum 0.0058 s in rise time, 0.0113 s in settling time, 0.465% in overshoot, and 0.0131 s in peak time). Additional analyses confirmed that both QIM and WMS individually contribute measurable gains, validating their joint integration. Implementation details and parameter settings are provided to ensure reproducibility. Full article

In agricultural automation, trajectory planning for fruit-picking robot arms must satisfy dynamic obstacle avoidance and real-time control constraints in complex orchards, forming a high-dimensional, constrained optimization problem. Due to strong nonlinearity and steep gradients, traditional planners often yield high-cost trajectories with unstable quality. This paper introduces a Reinforced Arctic Puffin Optimization (RAPO) algorithm for trajectory planning in high-dimensional, complex, constrained scenarios. RAPO improves Arctic Puffin Optimization (APO), which uses a two-stage foraging strategy but may suffer premature convergence, insufficient population diversity, and weak boundary handling. Dynamic fitness–distance balance (DFDB) adaptively coordinates exploration and exploitation. An elite-pool dynamic search strategy (DEPSS) combines t-distribution perturbation and Lévy flight to maintain diversity and enhance exploitation. A convex-lens opposition-learning boundary control method (CLOBC) improves out-of-bounds handling and reduces invalid search. Stochastic centroid opposition learning (SOBL) further suppresses premature convergence and expands coverage. On the CEC2017 benchmark (30/50/100 dimensions), RAPO outperforms nine algorithms in convergence speed and solution quality, verified by Wilcoxon and Friedman tests. In dense, narrow, and dynamic obstacle scenarios, RAPO achieves the lowest path cost, converges within 30 iterations, reduces variance, and generates smoother trajectories. This case study demonstrates RAPO’s robust mathematical performance, providing a robust and efficient framework for agricultural picking robots. Full article

The distribution of nutrients and microorganisms in sediments is not uniform, as it results from the complex interactions between chemical, biological, and physical transport processes. This study investigates, through a simplified model, the dynamics of a microbial population and its nutrients, accounting for the active metabolic state of the bacteria. Using the nutrient diffusion coefficient $d_2$ as a bifurcation parameter, we demonstrate that a Turing bifurcation, leading to spatial patterning, occurs at a critical value. Sufficient conditions for the stability of the resulting pattern are also established. Furthermore, by treating time delay as a bifurcation parameter, we prove the occurrence of Hopf bifurcation near the positive constant equilibrium solutions at a sequence of critical values, showing that time delay can induce spatially homogeneous and inhomogeneous periodic oscillatory patterns. Numerical simulations and solutions are provided to illustrate the theoretical findings. Full article

Background: Contemporary models of parental burnout conceptualize it as an interplay between parental demands and insufficient resources. Though, research and current models remain sparse in their understanding of these demands and dynamics within the context of managing a child’s sleep wellness and related problems, which constitute a fundamental aspect in early parenting. The present work addresses this gap by examining this issue comprehensively. Methods: 2291 mother–child dyads were recruited from two sources: a random population sample (n = 1409) and a clinical sample (n = 882) of mothers seeking consultation for their child’s sleep issues (0–5 years old). Mothers completed an extensive panel of validated instruments and survey questions covering burnout and psychopathologies, sleep parameters, psychosocial, organizational, and demographic variables. Inferential analyses, regression modeling, cluster analysis, and mediation models were applied. Results: Two distinct profiles of parental burnout emerged: one associated with child sleep disturbances and the other with general parenting stress. The strongest-weighted risk factors pertained to maladaptive beliefs and perceptions (e.g., shame, “I am bad parent”, “My child cries because I do not meet his needs”), as well as additive stressors such as interparental tension and daytime child behavioral problems. The strongest protective factors involved resources that reduced parental demands or facilitated recovery including couple satisfaction, a consistent bedtime routine, greater capacity to take breaks (e.g., additional caregivers, father nighttime involvement, parental cohabitation, and child screen time). Conclusion: The identification of two distinct burnout profiles highlights the importance of incorporating, or placing more centrally, the management of young children’s insomnia in contemporary theoretical models of parental burnout. This research highlights the need for interventions on healthy self-beliefs and perceptions, effective daytime parenting strategies, positive couple dynamics, consistency in bedtime routines, and equitable distribution of caregiving responsibilities between parents to reduce the risk of parental burnout. Full article

Population aging is widely regarded as a major fiscal risk for European welfare states and a central challenge to long-term fiscal sustainability. The article critically reexamines the deterministic assumption by assessing whether the fiscal implications of demographic aging in the European Union (EU) are mechanically driven or conditioned by policy context and institutional capacity. Using panel data for the EU-27 over the period 2014–2024, the study employs a two-way fixed-effects framework and interaction models to examine the relationship between demographic aging and key fiscal outcomes, including public pension expenditures, total social protection spending, and the general government balance. Furthermore, the analysis examines whether indicators associated with the silver economy, such as employment at older ages and digital inclusion, condition the fiscal effects of aging within countries over time. The results suggest that demographic aging does not exhibit a statistically significant association with pension or social protection expenditures once institutional heterogeneity and common shocks are controlled. In contrast to deterministic expectations, aging is positively associated with general government balance, suggesting the presence of policy-mediated fiscal adjustment dynamics rather than automatic fiscal deterioration. Interaction estimates further indicate that digital inclusion among older cohorts conditions the relationship between demographic aging and fiscal balance, while silver economy indicators do not display robust standalone fiscal effects. These findings should be interpreted as evidence of policy-mediated adjustment dynamics rather than as causal estimates of demographic effects. Building on these findings, the article advances a conceptual interpretation of the aging–fiscal nexus in which demographic pressures interact with institutional adaptation and policy capacity. Fiscal sustainability under demographic aging emerges as a policy-mediated outcome that may reflect broader institutional and governance contexts, rather than demographic structure alone. While governance quality is not directly estimated as an observable variable, the analysis interprets fiscal outcomes within a governance-conditioned institutional framework that emphasizes policy mediation rather than deterministic demographic effects. The findings contribute to ongoing debates on fiscal sustainability in aging societies by demonstrating that fiscal outcomes in the European Union are best understood as institutionally conditioned and policy-mediated rather than mechanically driven by demographic structure alone. Full article

The convergence of climate change, migration, and health represents a critical global challenge, with the Middle East and North Africa (MENA) region illustrating acute vulnerabilities while offering insight relevant beyond the region. Increasing exposure to extreme heat, droughts, and floods drives displacement, constrained mobility, and adaptive migration, placing additional pressure on already stretched health systems. This paper proposes an integrated Nexus Action Framework for Climate Change, Migration, and Health (NAF-CMH) to address these interlinked dynamics and move beyond fragmented, sector-specific responses. The framework conceptualizes human mobility both as a potential resilience strategy and as a determinant of health, encompassing climate-affected migrants, displaced populations, and those experiencing involuntary immobility across diverse pathways and settings. It promotes systematic integration of health considerations into climate adaptation and migration governance and situates these interventions within the broader agenda of climate-resilient health systems. Drawing on a non-systematic narrative review of peer-reviewed and grey literature, complemented by the authors’ expertise, the paper identifies seven interrelated pillars for coordinated policy and operational action. While grounded in MENA-specific vulnerabilities, the framework is flexible and adaptable to other regions facing climate-driven mobility challenges. By providing an operational architecture for multisector collaboration, the NAF-CMH supports policymakers, public health authorities, and migration actors in strengthening resilience, reducing vulnerability and safeguarding health amid accelerating climate impacts and evolving mobility patterns. Full article

As population aging accelerates, age-related declines in visual sensitivity and attentional control make older drivers more vulnerable to suboptimal in-vehicle interface designs. Head-up displays (HUDs) are intended to reduce gaze shifts by overlaying information within the forward field of view, yet empirical evidence remains limited on how specific HUD presentation strategies reshape older drivers’ visual attention allocation. Grounded in theories of visual attention and cognitive load, this study systematically investigates three design variables that are increasingly common in contemporary HUDs (including AR-HUDs): (1) dynamic versus static navigation cues, (2) pedestrian warning strategies under different lighting conditions, and (3) the spatial placement of high-priority information. We first conducted a formative user study to define variables and operationalizations, and then carried out three within-subject driving-simulator experiments using controlled HUD stimuli and eye tracking. Objective gaze measures (e.g., fixation count, total fixation duration, and time to first fixation) were combined with subjective preference ratings to characterize attentional capture, search efficiency, and potential attentional costs. Findings reveal a robust trade-off: continuously changing navigation cues enhance attentional capture but can also increase attentional “stickiness,” unnecessarily consuming older drivers’ limited attentional resources. In pedestrian hazard tasks, real-time overlay warnings that were spatially aligned with the hazard significantly improved visual localization under low-light conditions, outperforming early warnings and multi-stage strategies. Across tasks and layout conditions, the central HUD region showed a stable attentional advantage—placing critical information centrally elicited greater visual attention and stronger subjective preference. These results provide mechanistic evidence for how HUD parameters modulate older drivers’ attention and yield actionable implications for prioritization, temporal pacing of dynamic navigation cues, and a “center-first” layout strategy to guide age-friendly HUD design. Full article

Urban expansion presents significant challenges and opportunities for ecological conservation in developing countries, particularly in regions such as the Table Bay Nature Reserve in Cape Town, South Africa, where urban development interfaces with sensitive ecosystems. This article examines the complex dynamics between urban growth and ecological implications in this unique landscape, employing multi-temporal remote sensing techniques to analyze changes over time. By investigating the historical trajectory of urbanization in Table Bay, alongside its impacts on biodiversity and ecosystem services, we aim to underscore the urgent need for sustainable urban planning and conservation strategies. To analyze land use/land cover (LULC) dynamics over a 24-year period, this study leveraged a time series of satellite imagery processed within the Google Earth Engine (GEE) platform. Data can be accessed using their respective collection IDs within the GEE platform. The use of remote sensing tools aligns with Sustainable Development Goal (SDG) 15, which focuses on the protection, restoration, and sustainable use of terrestrial ecosystems. Urban encroachment analysis indicates that approximately 0.324 km² of built-up area expanded directly within the reserve boundary, highlighting a measurable degree of infringement into protected zones. The dominance of built-up and bare land classes highlights the early encroachment of urban infrastructure and anthropogenic disturbance, setting the stage for subsequent land cover transformations observed in later years (2012 and 2024). These findings demonstrate a persistent trend of urban encroachment and ecological alteration within the Table Bay Nature Reserve. With the increase in global population levels, urban expansion into protected conservation areas has become a critical environmental concern, threatening biodiversity globally. This challenge is particularly acute in developing countries as seen in regions like the Table Bay Nature Reserve in Cape Town, South Africa, where urban development is interfaced with sensitive ecosystems. Full article

In healthy ecosystems, large raptors such as the White-tailed Eagle perform the essential roles of predators, bioindicators, and umbrella species. Despite their importance, many species of raptors are globally endangered, and similarly, in the Republic of Moldova, 13 species of diurnal birds of prey went extinct in the last 7 decades. The White-tailed Eagle (Haliaeetus albicilla) is the only example of a raptor that has regionally made a demographic and distributional comeback after decades of absence. Following this comeback, a national monitoring scheme during 2014–2025, including a nest counting survey in 2022–2024, has been implemented to understand what the current national situation of the species is and its ecological preferences and threats, together with the fundamental ecological context that allowed the breeding population to adapt to an ever-changing landscape. Field research conducted over 12 years confirmed the breeding of eight pairs, with data indicating a minimum of 19–23 nesting pairs. Pairs generally avoid human-dominated landscapes, preferring higher coverage of wetlands and forests, but current data suggests frequent occupancy of suboptimal territories and increasing tolerance towards human activity and infrastructure. Although currently small, the breeding population experiences high breeding success with no negative outcomes recorded. However, droughts and forestry activities in the proximity of the nests potentially reduced and delayed breeding success. Current forestry and fish farming practices increase the vulnerability of the few known breeding pairs to habitat degradation, poaching, and deforestation. To improve the conservation status of this endangered raptor in the Republic of Moldova, as close as possible to Least Concern status, it is crucial to implement multi-purpose buffer zones around active nests during the breeding season and to further survey the breeding population and assess any demographic trends. Full article

Background and Objectives: Visual impairment and reduced stereovision significantly impact the quality of life and increase fall risk in older adults. While standard clinical assessment of visual functions is essential in this population, its use is often limited by the need for specialized equipment and trained personnel. Tablet-based screening tools offer a practical alternative but require clinical validation. This study aimed to assess the agreement, reliability, and diagnostic performance of a tablet-based screening application (index methods) compared to established clinical reference methods for assessing visual acuity (VA) and stereovision (SV) in adults over 60 years. Materials and Methods: This prospective, non-blinded, cross-sectional, feasibility study included two cohorts: a test–retest group of 24 older adults assessed twice within 7 days, and a clinical cross-sectional group of 135 participants recruited from primary care practices. VA was measured using tablet-based Landolt C test and compared with an ETDRS-style chart, while stereovision was assessed using tablet-based static and dynamic random dot stereograms and compared with the TNO stereotest. Agreement and reliability were evaluated using Bland–Altman analysis, intraclass correlation coefficients (ICC), and receiver operating characteristic (ROC) curves. Results: The index VA method demonstrated good test–retest reliability (ICC = 0.79) with no significant difference between repeated measurements. In the clinical cross-sectional group, visual acuity measurements showed a small mean bias (0.022 logMAR) between the index and reference methods, which remained within clinically acceptable limits, particularly in the intermediate acuity range. For stereovision, the index SV tests showed high test–retest agreement. Using a TNO cutoff of 480 arcsec, the index SV method demonstrated good diagnostic accuracy (AUC 0.87 for static and 0.85 for dynamic stimuli) with high sensitivity for detecting impaired stereovision. Conclusions: The tablet-based index method provided reliable and clinically comparable results for VA and SV assessments in older adults, supporting its potential use as a screening tool in primary care and community-based settings. Full article

As the global aging population increases, the early detection and prevention of Alzheimer’s disease (AD) have become important in public health. To solve the problems of subjectivity and low timeliness of traditional assessment methods, this paper proposes a multimodal dementia prevention system that combines physiological sensing, a gamification interface, and a classification model. The system includes an interactive joystick to measure pulse and blood pressure. A Chinese music game app increases the participation of the elderly and reduces their sense of rejection through gamification interaction. After the physiological data were standardized by Z-score, they were input into three small sample classifiers (Gaussian Naïve Bayes, Fisher Linear Discriminant Analysis, and Logistic Regression) for the binary classification of AD. The system performance was evaluated using the Leave-One-Out cross-validation method. Experimental results show that Logistic Regression performed best in situations with extremely small samples and class imbalance, with an F1-score of 0.700, which was higher than the other two. Dynamic features and model fusion technologies need to be integrated to further enhance the clinical application potential of the system in the early prediction of dementia. Full article

Rapid agricultural expansion threatens water security in one of the world’s largest hydroelectric systems, the Itaipu dam, located on the Brazil–Paraguay border. Yet regional hydrological responses to land cover change and climate variability remain insufficiently characterized at management-relevant scales. The Upper Paraná River Basin (UPRB), which sustains agriculture, hydropower, and municipal water supply across both countries, exemplifies this challenge as accelerating cropland conversion raises concerns about long-term water availability. This study investigates hydrological transitions and their statistical associations with land cover changes in the Itaipu study region from 2002 to 2023. We integrate GRACE/GRACE-FO (Gravity Recovery and Climate Experiment Follow-On), Terrestrial Water Storage Anomalies (TWSAs), MODIS (Moderate Resolution Imaging Spectroradiometer) land cover, CHIRPS (Climate Hazards Group InfraRed Precipitation with Station data) precipitation, and LandScan population density using Pettitt’s breakpoint test and Mann–Kendall trend analysis to detect temporal breakpoints and quantify co-variability between hydrology and land surface dynamics. Together, these methods identify a significant basin-wide shift in TWSAs in mid-2009, with storage increases of 151.6 cm at Itaipu and 103.1 cm at Yguazú Reservoir. Over the study period, cropland expanded from 13.5% to 37.9% of total land cover, while savanna declined from 28.1% to 24.2%. After 2009, correlations between land cover and TWSAs strengthened substantially, particularly for wetlands (r = 0.88), croplands (r = 0.73), and savannas (r = −0.81; all p < 0.001), indicating strong coupling between landscape transformation and basin-scale storage variability. Principal Component Analysis shows land use change explains 39–41% of TWSA variance, exceeding hydroclimatic contributions. Granger causality analysis reveals bidirectional coupling between wetlands and water storage at Itaipu, while cropland and savanna dynamics exert predictive influence on downstream hydrology in the Yguazú basin. Water balance decomposition further indicates a post-2009 regime shift, with residual storage transitioning from −10.6 to +4.7 and 78% greater runoff generation per unit precipitation, consistent with reduced infiltration capacity. Together, these findings underscore intensifying land–water feedback and the need for adaptive watershed management under expanding agriculture and climate variability. Full article

With the deepening implementation of the dual-carbon strategy, the penetration rates of distributed power sources and flexible loads in new distribution grids continue to rise, posing significant challenges to system security and stability due to output fluctuations and randomness. To enhance voltage quality and achieve low-carbon economic operation in distribution grids, this paper proposes a multi-objective optimization model for Distributed Energy Storage System allocation. The model integrates power quality, economic benefits, and net carbon emissions. To efficiently solve this high-dimensional nonlinear problem, an improved Multi-Objective Gray Wolf Optimization algorithm is proposed. It employs a chaotic map to initialize the population, enhancing global distribution uniformity. A nonlinear convergence factor is introduced to dynamically balance global exploration and local exploitation. A dynamic grouping collaboration strategy is designed, combining Lévy flight and the elite crossover strategy to enhance search capability and convergence accuracy. Simulations on an IEEE 33-node system show that the improved MOGWO-optimized energy storage scheme reduces average voltage deviation by 37.0%, total operating costs by 7.0%, and net carbon emissions by 4.1%, compared to a no-storage scenario. Compared to the standard MOGWO algorithm, the proposed method achieves further optimization across all objectives, validating its effectiveness and superiority in realizing coordinated energy storage planning that balances safety, economy, and low-carbon goals. Full article