Search Results (100)

LiDAR with direct time-of-flight (dToF) technology based on single-photon avalanche diode detectors (SPADs) has been widely adopted in various applications. However, a comprehensive theoretical understanding of its fundamental ranging performance bounds—particularly the degradation caused by pile-up effects due to system dead time and the potential benefits of photon-number-resolving detectors—remains incomplete and has not been systematically established in prior work. In this work, we present the first theoretical derivation of the Cramér–Rao lower bound (CRLB) for dToF systems explicitly accounting for dead time effects, generalize the analysis to SPADs with photon-number-resolving capabilities, and further validate the results through Monte Carlo simulations and maximum likelihood estimation. Our analysis reveals that pile-up not only reduces the information contained within individual ToF but also introduces a previously overlooked statistical coupling between distance and photon flux rate, further degrading ranging precision. The derived CRLB enables the determination of the optimal optical photon flux, laser pulse width (with FWHM of $\approx 0.56\tau$), and ToF quantization resolution that yield the best achievable ranging precision, showing that an optimal precision of approximately $0.53\tau /\sqrt{N}$ remains theoretically achievable, where $\tau$ is TDC resolution and N is the number of laser pulses. The analysis further quantifies the limited performance improvement enabled by increased photon-number resolution, which exhibits rapidly diminishing returns. Overall, these findings establish a unified theoretical framework for understanding the fundamental limits of SPAD-based dToF LiDAR, filling a gap left by earlier studies and providing concrete design guidelines for the selection of optimal operating points. Full article

Many transportation structures collapse or sustain severe damage as a result of natural disasters such as earthquakes, floods, wars, and similar attacks. These collapsed or severely damaged structures must be rebuilt and returned to service as quickly as possible. Water is used in the mix for cement-bound concrete roads. It is known that drought problems are emerging due to climate change and that water resources are rapidly depleting. Significant amounts of water are used in concrete production, further depleting water resources. In order to contribute to the elimination of these two problems, the usability of polyurethane resin binder in road pavement construction was investigated. Polyurethane resin binder road pavement is a new type of pavement that does not contain cement or bitumen as binders and does not contain water in its mixture. This new type of road pavement can be opened to traffic within 5–15 min. After determining the aggregate and binder mixture ratios, four different curing methods were applied to the created samples. After the curing, the samples were subjected to compression test, flexural test, Bohme abrasion test, freeze–thaw test, bond strength by pull-off test, ultrasonic pulse velocity (UPV) test, SEM-EDX analysis, XRD analysis, and FT-IR analysis. The new type of road pavement created within the scope of this study exhibited a compression strength of 41.22 MPa, a flexural strength of 25.32 MPa, a Bohme abrasion value of 0.99 cm³/50 cm², a freeze–thaw test mass loss per unit area of 0.77 kg/m², and an average bond strength by pull-off value of 4.63 MPa. It was observed that these values ensured the road pavement specification limits. Full article

Sustainable agricultural production systems are a global consensus. Their life-cycle economic feasibility is essential for long-term sustainable goals. This study integrates life-cycle costing with building energy simulation to assess the cost performance of conventional and innovative greenhouse tomato production systems in China’s Hexi Corridor, using dynamic thermal load modeling to overcome empirical-data limitations in traditional life-cycle costing. Under the facility-lease farming model, construction companies incur life-cycle costs of CNY 10.53·m⁻²·yr⁻¹ for the conventional concrete-walled Gobi solar greenhouse and CNY 10.45·m⁻²·yr⁻¹ for the innovative flexible insulation-walled Gobi solar greenhouses. However, farmer greenhouse contractors achieve 10.5% lower life-cycle costs for tomato cultivation in the conventional structure (CNY 2.87·kg⁻¹·yr⁻¹) than in the innovative one (CNY 3.21·kg⁻¹·yr⁻¹) due to 52.6% heating energy savings from the integrated active solar thermal systems. Furthermore, life-cycle cash flow analysis confirms construction companies incur non-viable returns, while farmers achieve substantial profits, with 52.5% higher cumulative profits obtained in the conventional greenhouse than the innovative greenhouse. This profit allocation imbalance threatens sustainability. Our pioneering stakeholder-perspective assessment provides evidence-based strategies for government, investors, and farmers to optimize resource allocation and promote sustainable Gobi agriculture. Full article

The dynamic environment of coastal regions subjects infrastructure to multiple interacting natural hazards, with the simultaneous occurrence of windstorms and earthquakes posing a particularly critical challenge. Unlike inland hazards, these coastal threats frequently exhibit irregular statistical behavior and terrain-induced anomalies. This study proposes a novel probabilistic framework to assess compound hazard effects, advancing beyond traditional single-hazard analyses. By integrating maximum entropy theory with bivariate Copula models, a unified return period analysis is developed to capture the joint probability structure of seismic and wind events. The model is calibrated using long-term observational data collected from a representative coastal zone since 2000. For the PGA marginal distribution, our sixth-moment maximum-entropy model achieved an R² of 0.90, compared with 0.57 for a conventional GEV fit—reflecting a 58% increase in explained variance. Analysis shows the progressive evolution of damage from slight damaged through moderate damaged and severe damaged to collapse for an 18-story reinforced concrete frame structure, and shows that the combined effect of seismic and wind loads results in risk probabilities of aforementioned damage state of approximately 2 × 10⁻³, 6 × 10⁻⁴, 2 × 10⁻⁴, and 3 × 10⁻⁵, respectively, under a 0.4 g ground motion and a concurrent wind speed of 15 m/s. Furthermore, when both the uncertainty of loss ratios and structural parameters are incorporated, the standard deviation of the economic loss ratio reaches up to 0.015 in the transition region (PGA 0.2–0.4 g), highlighting considerable variability in economic loss assessment, whereas the mean economic loss ratio rapidly saturates above 0.8 with increasing PGA. These findings demonstrate that uncertainty in economic loss is most pronounced within the transition region, while remaining much lower outside this zone. Overall, this study provides a robust framework and quantitative basis for comprehensive risk assessment and resilient design of coastal infrastructure under compound wind and seismic hazards. Full article

This study introduces a novel method for evaluating pile–soil interaction based solely on Dilatometer Test (DMT) results, enhancing and extending the established approach originally developed using Menard Pressuremeter Test (PMT) data. Currently, transfer functions utilizing DMT sounding results are in the early stages of development. Presented research fills the gap in DMT-based methods for pile design by introducing transfer functions for reversal loadings to calculate the unit shaft friction of screw displacement piles in Controlled Modulus Columns (CMC) technology. The proposed method utilizes DMT-derived soil parameters, offering a practical and accurate alternative to PMT-based models. Testing research fields were located in the Vistula Marshlands, Northern Poland. Site characterization consisted of piezocone (CPTU) and DMT soundings to characterize the soil profile and estimate soil parameters relevant for pile design. CMCs were installed and statically load tested under various loading schemes. Laboratory direct shear tests on smooth and rough soil-concrete interfaces were performed in both forward and backward directions (reversal loading) to simulate pile loading conditions. Results demonstrate improved adaptability of DMT-based transfer curves to local soil conditions and provide a reliable framework for predicting pile performance in soft soils. Proposed DMT-model returns similar ultimate bearing capacities of the pile to CPT 2012 method for first loading, simultaneously offering better agreement for reversal loading, a situation not accounted for in CPTU 2012 or most other CPT-based methods. Full article

Seoul systematically removed all graveyards that once lay within the city and its surrounding areas, a phenomenon notably distinct from urban development patterns in other parts of the world. After the Korean War, refugees and migrants poured into the devastated capital. In this postwar environment, cemeteries—traditionally sites of mourning and death—transformed into spaces of survival for displaced populations. With the military demarcation line preventing their return home, refugees began to envision their lost hometowns as “absent places”: unattainable utopias, idealized lands where all beauty resides—the very origin and endpoint of life. In contrast, Seoul, where they were forced to settle, became a “dystopia,” stripped of sanctity. Over time, however, the next generation reinterpreted this dystopia, gradually transforming it into a heterotopia. As Seoul’s urban landscape expanded, this heterotopia evolved into a Christian paradise. The second generation, having never experienced the trauma of displacement, found the newly constructed city comfortable and secure. Reinforced concrete buildings and asphalt roads became symbolic of paradise. The development of Gangnam—famously captured in Psy’s global hit “Gangnam Style”—represents a belated cultural revolution among younger generations in modern South Korea and exemplifies the transformation into a concrete paradise. Full article

The use of recycled aggregate concrete (RAC) in construction mitigates environmental pollution by repurposing demolition waste, but its lower compressive strength compared to natural aggregate concrete (NAC) limits broader application. Although carbon fiber reinforced polymer (CFRP) composites and polyvinyl chloride (PVC) tubes have individually been shown to improve concrete strength and ductility, existing studies focus on fully wrapped CFRP jackets on NAC columns and do not systematically explore CFRP–PVC hybrid confinement using strips on RAC. To address this research gap, this study investigates the axial compressive behavior of CFRP–PVC–RAC columns by varying CFRP strip width (from 25 to 75 mm), strip spacing (from 31 to 77.5 mm), and the number of CFRP layers (one to nine) over a central PVC tube. Axial compression tests reveal that specimens with a central CFRP strip width equal to or greater than 75 mm achieve peak loads up to 1331 kN and that, after rupture of the central strip, the remaining strips continue to carry load, producing a more gradual stress–strain decline and enhanced ductility compared to fully wrapped controls (peak load 1219 kN). These results show that CFRP–PVC composites enhance the axial compressive strength and ductility of RAC columns. The confinement mechanism increases the ultimate axial strain and redistributes transverse stresses, delaying brittle failure and improving deformation capacity. When two or more CFRP layers are applied, strip width and spacing affect axial stress by no more than three percent. Increasing layers from one to four raises axial strength by approximately 23 percent, whereas adding layers beyond four yields diminishing returns, with less than a six percent increase. Finally, a multilayer lateral confined pressure formula is derived and validated against thirty-two specimens, exhibiting errors no greater than three percent and accurately predicting effective confinement. These findings offer practical guidance for optimizing strip dimensions and layering in CFRP–PVC reinforcement of RAC columns, achieving material savings without compromising performance. Full article

Background: Diagnostic delay and error represent pervasive problems in healthcare with grave implications for treatment and prognosis. Though characteristic of human cognition, cognitive biases commonly contribute to delays in the physician decision-making process, particularly in atypical or complex presentations in youth. Methods: We present a case series of three adolescent athletes with varied clinical presentations whose diagnostic conceptualization and treatment were delayed in part due to cognitive biases with consequences for overall health and development, as well as return to sport. Results: The first case depicts how an atypical presentation of celiac disease was attributed to growing pains, illustrating the contribution of anchoring bias and confirmation bias in medical decision making. The second case represents the misattribution of chronic exertional compartment syndrome pain to growing pains and post-exercise soreness, highlighting the influence of ascertainment bias on the initial misdiagnosis. The third case describes how a vertebral mass was misdiagnosed as a left shoulder strain from weightlifting, depicting the contribution of anchoring bias and ascertainment bias in medical decision making. Conclusions: Early recognition of cognitive biases, including confirmation bias, anchoring bias, and ascertainment bias, is crucial for improving medical decision making, particularly in cases of rare or atypical presentations, reducing unnecessary diagnostic delays, and setting more realistic patient expectations. Through discussion of these cases, we highlight concrete steps to manage bias to facilitate timely diagnosis within the primary care and sports medicine setting. Full article

As a primary construction material, concrete plays a vital role in the development of infrastructure, including bridges, highways, and large-scale buildings. In Northeast China, the structural integrity of concrete faces severe challenges due to freeze–thaw cycles and substantial diurnal temperature variations. This study involved a thorough examination of concrete’s performance under varying numbers of temperature differential cycling (60 to 300) and freeze–thaw cycles (75 to 300). The results showed that both freeze–thaw and temperature differential cycling led to increasing mass loss with the number of cycles. Peak mass losses reached 3.1% and 1.2% under freeze–thaw and temperature differential cycles, respectively, while the combined action resulted in a maximum mass loss of 4.1%. The variation trends in dynamic elastic modulus and compressive strength differed depending on the environmental conditions. Under identical freeze–thaw cycling, both properties exhibited an initial increase followed by a decrease with increasing temperature differential cycles. After 120 temperature differential cycles, the dynamic modulus and compressive strength increased by 4.7–6.2% and 7.5–10.9%, respectively. These values returned to near their initial levels after 180 cycles and further decreased to reductions of 17.0–22.6% and 15.3–29.4% by the 300th cycle. In contrast, under constant temperature differential cycles, dynamic modulus and compressive strength showed a continuous decline with increasing freeze–thaw cycles, reaching maximum reductions of 5.0–11.5% and 18.1–31.8%, respectively. Notably, the combined effect of temperature differential and freeze–thaw cycles was significantly greater than the sum of their individual effects. Compared to the superposition of separate effects, the combined action amplified the losses in dynamic modulus and compressive strength by factors of up to 3.7 and 1.8, respectively. Additionally, the fatigue life of concrete subjected to combined temperature differential and freeze–thaw cycles followed a two-parameter Weibull distribution. Analysis of the S-N_f curves revealed that the coupled environmental effects significantly accelerated the deterioration of fatigue performance. Full article

The rapid expansion of the Internet of Things (IoT) has made software security and reliability a critical concern. With multi-language programs running on edge computing, embedded systems, and sensors, each connected device represents a potential attack vector, threatening data integrity and privacy. Symbolic execution is a key technique for automated vulnerability detection. However, unknown function interfaces, such as sensor interactions, limit traditional concrete or concolic execution due to uncertain function returns and missing symbolic expressions. Compared with system simulation, the traditional method is to construct an interface abstraction layer for the symbolic execution engine to reduce the cost of simulation. Nevertheless, the disadvantage of this solution is that the manual modeling of these functions is very inefficient and requires professional developers to spend hundreds of hours. In order to improve efficiency, we propose an LLM-based automated approach for modeling unknown functions. By fine-tuning a 20-billion-parameter language model, it automatically generates function models based on annotations and function names. Our method improves symbolic execution efficiency, reducing reliance on manual modeling, which is a limitation of existing frameworks like KLEE. Experimental results primarily focus on comparing the usability, accuracy, and efficiency of LLM-generated models with human-written ones. Our approach was integrated into one verification platform project and applied to the verification of smart contracts with distributed edge computing characteristics. The application of this method directly reduces the manual modeling effort from a month to just a few minutes. This provides a foundational validation of our method’s feasibility, particularly in reducing modeling time while maintaining quality. This work is the first to integrate LLMs into formal verification, offering a scalable and automated verification solution for sensor-driven software, blockchain smart contracts, and WebAssembly systems, expanding the scope of secure IoT development. Full article

An Fe-based shape memory alloy (Fe-SMA) is an alloy that has a characteristic of being able to return to its original shape when heated, even after undergoing plastic deformation. Many researchers have conducted various studies to understand the effectiveness of using Fe-SMA in concrete structures. Most studies selected the heating temperature of Fe-SMA to be below 160 °C based on the logic that concrete hydrolyzes when its temperature exceeds 160 °C. However, because the recovery stress of Fe-SMA increases as the heating temperature increases, it is expected that greater prestress could be introduced when the heating temperature is high. In this study, to confirm this, a numerical study was conducted to evaluate the effect of Fe-SMA heating temperature on the flexural performance of concrete members through finite element (FE) analysis. The analysis results showed that the initial crack load of the specimen increased by about 89% to 173% as the heating temperature of Fe-SMA increased. In addition, the accuracy of the proposed FE model (FEM) was verified through experiments. As a result, it was confirmed that the proposed FE analysis can relatively accurately predict the failure mode and load–displacement relationship of the specimen. Full article

The article engages in the undisciplining of the study of religion and proposes two central concepts/approaches for how to do so: the pluriverse and materiality. But what is undisciplining? And is it needed? To frame the undisciplining of the study of religion and render visible how I conceive of it as a needed practice, the article discusses the relationship between knowledge, materiality, power, and transformation. This relationship is concretized by prioritizing critical decolonial perspectives from the South African context. Here, I center materiality and the material effects of colonial discourse and epistemology as critical entry points. I also highlight the importance of embodied approaches to knowledge, illustrated through decolonial feminist engagements with post-qualitative methodologies. Informed by these critical insights, I unpack the concept of the pluriverse and highlight its epistemic and methodological relevance for the undisciplining of the study of religion. (Re-)turning to materiality, I foreground materiality as a creative and critical knowledge framework and argue for the varying ways it may function for rethinking and undisciplining the study of religion. Full article

Background/Objectives: Anxiety and depression result in a greater health burden; both can impact functionality and quality of life. This review aims to understand the association between anxiety, depression, functionality, and quality of life. Although three systematic reviews exist, one focuses on quality of life in depression and anxiety, while the others address functionality in depression and anxiety, with the former being more recent and the latter two being older. The association between these four variables will be explored. Methods: A literature search of MEDLINE with Full Text, CINHAL PLUS with Full Text, Psychology and Behavioral Sciences Collection, and Academic Search Complete was conducted from 1 January 2017 to 22 November 2022. Seven studies involving 2279 adults were included. Results: All studies analyzed the association between anxiety and/or depression with functionality and/or quality of life, in a population with a primary chronic condition. We found the higher functionality (return to work, no sedentary lifestyle, and no fatigue) and quality of life are, the lower the values of anxiety and depression will be. The HADS is a consensual instrument to access anxiety and depression, but the same cannot be said for assessing functionality and quality of life. Conclusions: The severity of the chronic disease and the loss of functionality and quality of life seem to increase psychological distress. This study highlights the importance of a multidisciplinary and holistic approach, focusing not only on clinical outcomes but also on overall well-being. Further longitudinal research is needed to support the association between these variables to draw more concrete conclusions with scientific evidence. Full article

Complex wind and temperature characteristics in the Yellow River basin (YRB) challenge the safety and durability of long-span concrete-filled steel tube (CFST) bridges greatly. To address this issue, it is important to accurately assess the joint actions of wind and temperature. In this paper, the joint actions of wind and temperature in eight typical YRB cities are analyzed. The joint distributions of wind speed and air temperature are developed with the Archimedean Copula, and the Kendall return period is used for occurrence probability estimations. Eight wind–temperature combinations are considered. Responses for these combinations are calculated and compared with specification actions. Results show significant wind–temperature variations in the YRB. When wind actions adopt the univariate representative values (URVs), the temperature actions are reduced by 20–40%; when temperature actions use URVs, wind actions experience a reduction by more than half of their URVs. The joint responses can sometimes exceed, but are mostly less than, the specification responses, with a maximum strength margin over 11 MPa. These efforts suggest that the proposed joint actions can expand the provisions in the General Specification and provide guidance for the design of long-span CFST bridges. Full article

In many developing countries, economic growth is often prioritized, sidelining critical issues such as social inequality, pollution, climate change, ocean degradation, and pressing needs for health, education, food, and water management. Traditional linear models in organizations, based on product innovation and hierarchical governance, have been successful in certain contexts but are no longer viable in the face of finite natural resources and environmental degradation. This paper proposes a Systems Approach to Circular Economy as a practical framework for achieving “circular business-driven sustainability”, a concept proposed by major global organizations such as COP-25. This approach redefines sustainability, aiming to generate “sustainable wealth increasing returns” that benefit all key stakeholders, including the environment, society, and the economy. The primary objective of this paper is to introduce a new paradigm that facilitates the transition to more conscious, long-term growth. The proposed circular iterative thinking framework shifts from linear, reductionist thinking to a more holistic, systemic vision, underpinned by disruptive sustainable innovation. This novel paradigm creates positive impacts across the economy, environment, and global geopolitics. The paper demonstrates the application of this framework in two case studies, providing concrete evidence of its utility in real-world scenarios, including Heineken’s sustainable practices at its Meoqui brewery, which recovered methane for energy use, reduced water consumption, and contributed to local irrigation. The results underscore the effectiveness of the Systems Approach to Circular Economy in achieving economic decoupling and enhancing sustainability. Full article