Search Results (150)

Taking the shield construction of Xiamen Metro Line 2 tunnel side-crossing the Tianzhushan overpass and under-crossing the Shen-Hai Expressway as the engineering background, FLAC3D 6.0 software was used to examine the deformation of adjacent structures based on shield construction parameters in upper-soft and lower-hard strata. The reliability of the numerical simulation results was verified by comparing measured and predicted deformations. The study results indicate that deformation of the pile will occur during the construction of the tunnel shield next to the pile foundation. The shape of the pile deformation curve in the horizontal direction is significantly influenced by the distance from the pile foundation to the adjacent tunnel’s centerline, as well as by soil bin pressure, grouting layer thickness, and stress release coefficient. During the tunnel shield construction beneath the expressway, increasing the soil bin pressure, the grouting layer thickness, and reducing the stress release coefficient can effectively minimize surface deformation and differential settlement on both sides of the deformation joints between the bridge and the roadbed. The practice shows that, by optimizing shield construction parameters in upper-soft and lower-hard strata, the deformation of nearby bridges and pavements can be kept within allowable limits. This is significant for reducing construction time and costs. The findings offer useful references for similar projects. Full article

Background/Objectives: Among the paranasal sinuses, the maxillary antrum holds unique clinical relevance due to its proximity to the alveolar process of the maxilla, which houses the teeth. This study aimed to evaluate the position of the root apices of the maxillary canines and posterior teeth relative to the maxillary sinus floor in Romanian subjects. Methods: Data for the study were retrospectively obtained from cone-beam computed tomography (CBCT) scans. The evaluation considered the pattern of proximity to the sinus floor for each tooth type, comparisons of the sinus relationships of teeth within the same dental hemiarch, as well as those of homologous teeth, and variation in root-to-sinus distance in relation to sex and age. Nonparametric tests were used for statistical analysis, and multiple comparisons were performed using Bonferroni post hoc correction. Results: The study included 70 individuals aged 20 to 60 years. The distance to the sinus floor decreased progressively from the first premolar to the second molar, with median values of 3.68 mm (first premolar), 1.45 mm (second premolar), 0.50 mm (first molar), and 0.34 mm (second molar) (p < 0.01). Stronger correlations were observed between adjacent teeth than between non-adjacent ones. The distances to the sinus floor were greater on the right side compared to the left; however, these differences were not statistically significant (p > 0.05 for all teeth). Concordance between left and right dental hemiarches regarding the closest tooth to the sinus floor was found in 70% of cases (n = 49), most frequently involving the second molars (n = 38; 54.3%). On average, the distance from the sinus floor was smaller in males compared to females, with statistically significant differences observed only for the second molar. Increased age was associated with a greater distance to the sinus floor. Conclusions: Of all the teeth investigated, the second molar showed the highest combined prevalence of penetrating and tangential relationships with the maxillary sinus. At the dental hemiarch level, the second molar was most frequently the closest tooth to the sinus floor, and in the majority of cases, at least one posterior tooth was located within 0.3 mm. Accurate preoperative assessment of tooth position relative to the sinus floor is essential when performing non-surgical or surgical root canal therapy and extractions of maxillary molars and premolars. CBCT provides essential three-dimensional imaging that improves diagnostic precision and supports safer treatment planning for procedures involving the posterior maxilla. Full article

Background: The interdental papilla plays a critical role in maintaining both the esthetic and functional integrity of the periodontium. Although the relationship between the papilla presence and the contact point–bone crest distance is well established, the impact of vertical bone defect morphology—common in periodontitis—remains largely unexplored. Aim: To assess the relationship between the loss of interdental papilla height and three site-specific factors—vertical bone defect morphology, probing depth, and papilla base width—in patients with periodontitis. Materials and Methods: Ten periodontitis patients contributing 28 interdental papillae adjacent to vertical bone defects were included. The recorded parameters included probing depth, papilla base width, and loss of papilla height. Intraoperative measurements of defect depth, mesiodistal width, and buccolingual width were also obtained. Patient-level variables, such as age, sex, oral hygiene, and gingival phenotype, were not controlled or included in the analysis, due to the small number of participants and the study’s focus on defect-level characteristics. Spearman’s rank correlation was used due to non-normal data distribution. Results: A moderate positive association was observed between the probing depth and loss of papilla height (ρ = 0.353), approaching but not reaching statistical significance (p = 0.066). Weak, non-significant associations were found with the remaining parameters (p > 0.05). Conclusions: Although no statistically significant associations were found, observed trends may indicate site-specific influences on the loss of papilla height. These preliminary findings highlight the need for further research with larger, well-characterized cohorts to better understand the factors affecting papilla stability in periodontitis. Full article

Accurate traffic light status detection and the appropriate response to changes in that status are crucial for autonomous driving systems (ADSs) starting from SAE Level 3 automation. The dilemma zone problem occurs during the amber phase of traffic lights, when the ADS must decide whether to stop or proceed through the intersection. This paper proposes a methodology for developing a runtime monitor that addresses the dilemma zone problem and monitors the autonomous vehicle’s behavior at traffic lights, ensuring that the ADS’s decisions align with the system’s safety requirements. This methodology yields a set of safety requirements formulated in controlled natural language, their formal specification in linear temporal logic (LTL), and the implementation of a corresponding runtime monitor. The monitor is integrated within a safety-oriented software architecture through a modular autonomous driving system pipeline, enabling real-time supervision of the ADS’s decision-making at intersections. The results show that the monitor maintained stable and fast reaction times between 40 ms and 65 ms across varying speeds (up to 13 m/s), remaining well below the 100 ms threshold required for safe autonomous operation. At speeds of 30, 50, and 70 km/h, the system ensured correct behavior with no violations of traffic light regulations. Furthermore, the monitor achieved 100% detection accuracy of the relevant traffic lights within 76 m, with high spatial precision (±0.4 m deviation). While the system performed reliably under typical conditions, it showed limitations in disambiguating adjacent, irrelevant signals at distances below 25 m, indicating opportunities for improvement in dense urban environments. Full article

Existing methods for calculating terrain entropy in grid digital elevation models (DEMs) often face computational anomalies in specific topographies within small windows. To address this issue, an improved method was developed based on the Euclidean distance approach. This method was inspired by Claramunt’s technique of weighting information entropy by the average distance between points with the same value and different values. Specifically, vectors were formed between grid points and categorized by value consistency and relative positions. Those formed between points of different values were classified by the value of the starting point as well as parallel and adjacent relationships. This comprehensive grouping strategy was integrated into distance calculations, becoming a new probability operator that accurately reflects terrain spatial characteristics. Experimental verification confirms that the method proposed aligns with the fundamental concept of entropy, yielding a regression equation of $y=0.011\ln x+0.463$ with a coefficient of determination of 94.73%, a reliability of 44.015, and a measurement ability of 0.757. For the mixed iterative images with gradually increasing spatial disorder, their entropy values should follow a logarithmic trend. Therefore, a logarithmic function is used for fitting. A determination coefficient greater than 50% indicates that the method adheres to the original definition of entropy and is effective in capturing the increasing spatial disorder of the grid DEM. A lower reliability value suggests smoother data computation between the two iterations. A lower measurement ability value indicates slower convergence for grid DEMs with gradually increasing spatial disorder. The improved method was also tested on simulated and real DEMs, and the results showed a strong correlation between calculated terrain entropy values and terrain complexity. By effectively capturing spatial information changes, this approach overcomes the shortcoming of computational anomalies and demonstrates high reliability in terrain entropy calculation in grid DEMs. Full article

Lead (Pb) poses a significant risk to human health and the environment. Global Pb production and consumption have markedly risen due to unregulated development and urbanization, Pb smelting, and Pb-acid battery processing. This study addresses the issue of elevated heavy metal concentrations in dust, soil, and groundwater in Shubra Al Khaymah due to the Awadallah Pb smelter. Pb concentration in soil and groundwater escalates in proximity to the Awadallah smelter and diminishes with distance from it—the surface soil functions as a repository for heavy metals. The concentrations of Pb (50–1500 µg/L), manganese (Mn) (1–750 µg/L), iron (Fe) (200–1250 µg/L), and boron (B) (250–1750 µg/L) in the groundwater stratum exceeded drinking and irrigation standards. A solution to the groundwater system issue is proposed by employing pumping wells adjacent to the riverbed to recover the contaminated water from the hydrogeological environment. Processing Modflow Path (PMPATH) program may delineate groundwater protection zones according to the travel time of 150 days (Zones 1 and 2) and the whole watershed source (Zone 3). An injection well was constructed to replenish excellent water quality in the groundwater aquifer in the upstream region. A 3D model of dissolved matter transport was created to examine the concentration distribution across remediation time in the contaminated region. This model demonstrates that, after 365 days of injection, the C/Co concentration ratio exceeded 70% in the downstream area, rendering it appropriate for drinking and irrigation. The alternate strategy is to encapsulate the severely contaminated zone. All measures aim to decrease the piezometric pressure in the vicinity, directing groundwater flow towards the contaminated zone, as accomplished by Processing Modflow Windows (PMWIN). Full article

Afforestation has been considered to be the cost-effective way to sequestrate carbon (C) dioxide from the atmosphere in the soils, while concurrent responses of soil inorganic C (SIC) and soil organic C (SOC), and their turnover are still not well-defined. During the C cycle, inorganic C is enriched in heavy isotopes (¹³C), while organic C, due to photosynthetic fractionation, is enriched in light isotopes (¹²C). This leads to distinct C isotope fractionation in terrestrial ecosystems. In this study, 72 paired soils (0–20 cm) from poplar shelterbelts and adjacent farmland sites were collected in six regions (Zhaozhou, Fuyu, Dumeng, Zhaodong, Lanling, and Mingshui) of northeastern China. Five soil fractions of dissolved organic C (DOC), particulate organic matter (POM), sand and stable aggregates (S + A), silt and clay (S + C), and resistant SOC (rSOC) and bulk soils were used in C content assay and the natural δ¹³C determination. The results showed that, compared with SOC, poplar shelterbelts resulted in SIC accrual in the soils across all six sites; however, only half of the six sites showed SOC accrual, indicating an ambiguous effect of afforestation on SOC. The natural δ¹³C method could identify the SOC turnover owing to the C isotopic discrimination. The δ¹³C–SOC-derived turnover ratio was 23%. When SIC was included in the δ¹³C measurement, bulk soils and four soil fractions (S + C, S + A, rSOC, DOC) showed a 2%–10% lower turnover percentage than the δ¹³C–SOC-derived turnover ratios. The SIC inclusion resulted in the dependency of δ¹³C–TC (TC = SIC + SOC) values on SOC (negative, R²: 0.21–0.44) and SIC content (positive, R²: 0.39–0.63). By contrast, when SIC was excluded, the δ¹³C–SOC values were independent of them (R² < 0.18). Redundancy ordination analysis manifested that more SOC in the soils, together with more POM and farming uses would be accompanied with the lower δ¹³C values. Moreover, forest characteristics (e.g., age and density) and farmland backgrounds (e.g., crop history and distance between forest and farmland) could explain differences in δ¹³C-related features. Our results highlighted that SIC in natural δ¹³C determination underestimated the C turnover ratio in general. However, SIC storage should be included in the soil C sequestration evaluation owing to a general SIC accrual pattern across regions when compared with those of SOC. Full article

Access to green spaces is essential for promoting public health, reducing inequalities, and fostering urban resilience. This study evaluates the 3-30-300 indicator as a tool for assessing green space accessibility in Montreal, Canada. The framework sets three goals: every resident should see three trees from their home, live in a neighborhood with at least 30% tree canopy, and have a park or green space within 300 m. Using geospatial analysis, this study examines how well these criteria are met across Montreal’s neighborhoods and investigates disparities linked to socio-economic factors. The study reveals a significant variability in the distribution of green spaces across Montreal neighborhoods, as measured by the 3-30-300 metric. Tree canopy coverage ranges from 0.8% to 84%, with a median of 25.7%, while distances to parks vary from adjacent to over 2.4 km. The number of trees around residences is highly skewed, ranging from 0 to 771, reflecting substantial heterogeneity in green space accessibility. Spatial analysis highlights pronounced inequalities, with only 19.4% of neighborhoods meeting all three criteria. Hotspots of compliance are concentrated in peri-central and well-established residential areas in the West and East, while central and peripheral neighborhoods, especially in northeast Montreal, frequently fail to meet the standards. These findings underscore strong spatial disparities in urban green infrastructure, consistent with global studies on inequitable access to green spaces. Full article

To create a discretized prediction model for the deformation of an adjacent pipeline, the pipeline structure is discretized, the differential equations governing the longitudinal deformation of the pipeline are inferred, and the displacement expressions and the solution methods of the virtual nodes of each unit are provided after discretization. This approach is based on the Pasternak foundation beam theory. It aims to address the issue of the difficulty in predicting the deformation of the adjacent pipeline caused by shield tunneling in a saturated soft ground layer in the Yangtze River Delta. The deformation pattern of the surrounding soil is determined and confirmed through additional numerical simulation, and the discretized prediction model is contrasted with the conventional Winkler foundation beam model and the Pasternak foundation beam model. The findings demonstrate that the discrete prediction model is simpler to solve and more accurately describes the deformation characteristics of the adjacent pipeline as well as the deformation distribution law. The calculated deformation characteristics primarily appear as the adjacent pipeline’s deformation due to the double tunnel boring exhibiting a “mono-peak shape” with a large middle and small ends, which is consistent with the actual situation. The two main factors influencing the pipeline deformation are the shield tunneling distance and pipeline spacing; the former has a negative correlation with the pipeline deformation, while the latter has a positive correlation. This work can offer a straightforward deformation prediction technique for shield tunneling in the Yangtze River Delta’s saturated soft ground next to existing pipelines. Full article

Traffic congestion at a single intersection can propagate and thus affect adjacent intersections as well, potentially resulting in prolonged gridlock across an entire urban area. Despite numerous research efforts aimed at developing intelligent traffic signal control systems, urban areas continue to experience traffic congestion. This paper presents a novel agent-based fuzzy traffic control system for multiple road intersections. The proposed system is designed to operate in a decentralized manner, with each intersection having its own agent (fuzzy controller) functioning concurrently. The intelligent fuzzy controller of the system can recognize emergency vehicles, assess the queue length and waiting time of vehicles, measure the distance of vehicles from intersections, and consider the cumulated waiting times of short vehicle queues. Two distinct types of agent-based intelligent fuzzy traffic control systems were implemented for comparison: one involving collaboration between an agent and its immediate neighboring agent(s) (where one intersection exchanges traffic data with its immediate neighboring intersection(s)), and the other implementing a non-collaborative agent-based intelligent fuzzy traffic control system (where the individual intersection has no direct communication). Following the experimental simulations, the results were compared with those of existing intelligent fuzzy traffic control systems that lack any module to calculate the distance of the vehicles from the intersection. The results demonstrated that the proposed agent-based system of controllers exhibited superior performance compared with the existing fuzzy controllers in terms of indicators such as average waiting time, fuel consumption, and CO₂ emissions. For instance, the proposed system reduced the average waiting time of vehicles at an intersection by 48.65% compared with the existing three-stage intelligent fuzzy traffic control system. In addition, a comparison was conducted between non-collaborating and collaborating agent-based intelligent fuzzy traffic control systems, where collaboration achieved better results than the non-collaborating system. In the simulation experiments, an interesting new feature emerged: despite any direct communication missing at multiple intersections, green waves evolved with time. This emergent feature suggests that fuzzy controllers have the potential to evolve and adapt to traffic complexity issues in urban environments when operating in an autonomous agent-based mode. This study demonstrates that agent-based fuzzy controllers can effectively communicate with one another to share traffic data and improve the overall system performance. Full article

A novel path-planning method utilizing the trapezoid, adjacent, and distance, (TAD) characteristics of frontiers is presented in this work. The method uses the mobile robot’s sensor range to detect frontiers throughout each exploration cycle, modifying them at regular intervals to produce their parameters. This well-thought-out approach makes it possible to choose objective points carefully, guaranteeing seamless navigation. The effectiveness and applicability of the suggested approach with respect to exploration time and distance are demonstrated by empirical validation. Results from experiments show notable gains over earlier algorithms: time consumption decreases by 10% to 89% and overall path distance for full investigation decreases by 12% to 74%. These remarkable results demonstrate the efficacy of the suggested approach and represent a paradigm change in improving mobile robot exploration in uncharted territory. This research introduces a refined algorithm and paves the way for greater efficiency in autonomous robotic exploration. This study opens the door for more effective autonomous robotic exploration by introducing an improved algorithm. Full article

Satellite image generation has a wide range of applications. For example, parts of images must be restored in areas obscured by clouds or cloud shadows or areas that must be anonymized. The need to cover a large area with the generated images faces the challenge that separately generated images must maintain the structural and color continuity between the adjacent generated images as well as the actual ones. This study presents a modified architecture of the generative adversarial network (GAN) pix2pix that ensures the integrity of the generated remote sensing images. The pix2pix model comprises a U-Net generator and a PatchGAN discriminator. The generator was modified by expanding the input set with images representing the known parts of ground truth and the respective mask. Data used for the generative model consist of Sentinel-2 (S2) RGB satellite imagery as the target data and OpenStreetMap mapping data as the input. Since forested areas and fields dominate in images, a Kneedle clusterization method was applied to create datasets that better represent the other classes, such as buildings and roads. The original and updated models were trained on different datasets and their results were evaluated using gradient magnitude (GM), Fréchet inception distance (FID), structural similarity index measure (SSIM), and multiscale structural similarity index measure (MS-SSIM) metrics. The models with the updated architecture show improvement in gradient magnitude, SSIM, and MS-SSIM values for all datasets. The average GMs of the junction region and the full image are similar (do not exceed 7%) for the images generated using the modified architecture whereas it is more than 13% higher in the junction area for the images generated using the original architecture. The importance of class balancing is demonstrated by the fact that, for both architectures, models trained on the dataset with a higher ratio of classes representing buildings and roads compared to the models trained on the dataset without clusterization have more than 10% lower FID (162.673 to 190.036 for pix2pix and 173.408 to 195.621 for the modified architecture) and more than 5% higher SSIM (0.3532 to 0.3284 for pix2pix and 0.3575 to 0.3345 for the modified architecture) and MS-SSIM (0.3532 to 0.3284 for pix2pix and 0.3575 to 0.3345 for the modified architecture) values. Full article

Constructing high-speed railways (HSRs) is critical for developing countries to stimulate economic growth and urbanization. This study focuses on the Lao section of the China–Laos Railway (CLR) and employs explicitly spatial remote sensing images to investigate the urban development surrounding HSR stations. Data-driven machine learning and causal inference approaches are integrated to quantify the spatial–temporal evolution and discover its driving factors. The results suggest that the CLR has had positive spatial spillover effects on the development of the surrounding urban space. These spillover effects have exhibited a distance attenuation pattern, reflecting obvious development in 2D rather than in 3D urban space. Meanwhile, the distance to stations and adjacent city centers as well as functional urban characteristics, such as land use patterns and industrialization level, have significantly influences the surrounding spatial development. Specifically, in industrial-dominated cities, the surrounding spatial changes have been most significant under the influence of the HSR. Change related to industrial and residential land use has shown significant land expansion patterns and increased utilization efficiency, reflecting that industrialization and urbanization have been the primary drivers of land demand surrounding the HSR. The findings offer valuable insights and references for developing nations to formulate and implement spatial management policies and initiatives related to HSR. Full article

Many municipalities around the world place their production wells in shallow alluvial aquifers that are adjacent to streams. Pumping these wells then induces the infiltration of surface water into the aquifer, allowing the greater extraction of water without significantly depleting the aquifer. However, induced infiltration poses a risk of introducing contamination from surface water into groundwater systems. The goal of this study was to quantify the amount of induced infiltration due to municipal pumping at the Four Mile Creek well field in Oxford, Ohio, using stable isotopes of water oxygen (δ¹⁸O) and deuterium (δ²H). In areas of municipal pumping, we sampled water from the production wells, Four Mile Creek, and from monitoring wells that we hypothesized to be both influenced and not influenced by induced infiltration. Samples were collected over 10 months in 2012 and over 12 months in 2021. In 2012, surface water δ¹⁸O values ranged from −3.89 to −8.04‰, and δ²H ranged from −26.55 to −55.65‰ at sampling sites. PW1 δ¹⁸O values ranged from −4.71 to −7.39‰ with a mean of −6.61 and −32.01 to −47.86‰ with a mean of −42.74‰ for δ²H. PW2 δ¹⁸O values ranged from −5.74 to −7.34‰, with a mean of −6.45‰, and δ²H ranged from −36.29 to −47.82‰ with a mean of −42.43‰. PW3 had lower values of both δ¹⁸O and δ²H, ranging from −6.36 to −8.02‰ and −47.7 to −40.35‰, and with means of −7.08 and −45.11, respectively. In 2021/2022, surface water δ¹⁸O values ranged from −5.32 to −7.93‰, and the δ²H ranged from −36.14 to −50.56‰. PW1 δ¹⁸O values ranged from −6.15 to −7.54‰ with a mean of −7.13‰, and δ²H ranged from −43.52 to −49.01‰ with a mean of −45.99‰. PW2 δ¹⁸O values ranged from −5.72 to −7.34‰, with a mean of −6.70‰, and δ²H ranged from −36.69 to −46.14‰, with a mean of −43.61‰. Using the time averaged values of δ¹⁸O of groundwater, production wells and surface water, the percentages of surface water resulting from induced infiltration in 2012 were 57%, 59% and 15% at the three wells, respectively, while in 2021, PW1 had 35% and PW2 91%. The amount of induced infiltration was apparently related to the pumping rates of the production wells, the length of time of pumping and the distance between Four Mile Creek and production wells. Our results indicate that stable isotopes of water provide a reliable method of quantifying groundwater/surface water interaction in alluvial aquifers. Full article

Based on a comprehensive analysis of the existing methods for measuring adjacent well distances, along with their advantages and disadvantages, this study employs theoretical analysis, simulation experiments, and other comprehensive research methods to investigate a distance measurement method based on current excitation. In response to the need for measuring and controlling the connection of relief wells, a method utilizing dual-electrode current excitation during drilling is proposed. This approach facilitates synchronous excitation measurements while drilling, significantly reducing both time and costs while ensuring safety and efficiency, making it particularly suitable for the connection operation of relief wells that involve safety risks. Firstly, this paper establishes a drilling with measurement model corresponding to the excitation mode, which derives the calculation formulas for the target casing current amplitude attenuation, as well as the induced magnetic field distribution within the formation. Additionally, it provides the calculation methods for determining the target well distance and azimuth direction. Lastly, the impact levels of various key factors are verified through numerical calculations and simulation analyses, which confirm the correctness and effectiveness of this distance measurement method. The findings from this research establish both a core theoretical foundation and a technological basis for the real-time measurement of adjacent well distances during relief well operations. Full article