Search Results (7,076)

The Earth’s lithosphere, the rigid outermost layer of the planet, is composed of numerous tectonic plates of varying sizes that move over the underlying asthenosphere. The motion and interaction of these plates give rise to a wide range of geodynamic processes. Accurate monitoring of these processes is essential for maintaining a stable, up-to-date, and reliable terrestrial reference frame. This study investigates the horizontal and vertical motions of the Antarctic Plate resulting from its interactions with adjacent plates. Tectonic plate movements can be determined using several space-geodetic techniques, including Global Navigation Satellite Systems (GNSS), Very Long Baseline Interferometry (VLBI), Satellite Laser Ranging (SLR), and Interferometric Synthetic Aperture Radar (InSAR). Among these methods, GNSS is currently the most widely used, as plate motions can be derived from continuous observations recorded at permanent stations and processed using scientific or commercial software. Within the scope of this research, GNSS data collected between 2020 and 2023 were processed using the GAMIT/GLOBK V.10.7 software package to estimate the coordinates and velocities of stations located on the Antarctic, South American, African, and Australian Plates in the ITRF14 reference frame. Furthermore, plate-fixed solutions were generated to analyze the relative motion of the Antarctic Plate with respect to neighboring plates. The results indicate that the Antarctic Plate moves at an average velocity of approximately 4–18 mm/year in the ITRF14 frame. The plate diverges from both the African and Australian Plates and exhibits predominantly strike-slip motion relative to the South American Plate. A comparison with existing global plate motion models demonstrates that the obtained velocities are consistent within 0–5 mm/year. Full article

A 2-acre reedbed system, cultivated with Phragmites australis, was established and utilized to remediate groundwater polluted with chlorinated hydrocarbons at a former industrial site. The reedbed comprised a combination of horizontal and vertical systems over four parallel installations, with a treatment capacity of 305 m³/day. The mean inlet concentration for the four-line treatment was 112.4 mg/L, which was below the specified inlet concentration of 250 mg/L. From 2019 to 2024, the reedbed system effectively eliminated 1,2-Dichloroethane (1,2-DCA), with average removal rates of 97.7%, 98.8%, 98.5%, and 98.6% for Lines 1 to 4, respectively. The average outlet concentrations of 1,2-DCA were 0.70 mg/L, 0.40 mg/L, 0.42 mg/L, and 0.52 mg/L for Lines 1–4, respectively, resulting in an overall average of 0.51 mg/L. We performed the assessment of natural attenuation by first-order decay kinetics for five groundwater monitoring wells, showing values between 0.0012/year and 0.0036/year (shallow wells), 0.0003/year and 0.0021/year (middle wells), and 0.0003/year and 0.0009/year (deep wells). Here, shallow groundwater showed the highest kinetic rates compared to middle and deep groundwater wells. The results indicated that the reedbed system removed the bulk of contaminants through active biological processes involving plants and microbes, and that natural attenuation further degraded 1,2-DCA in the groundwater profiles. Based on data monitoring from 2019 to 2024, the reduction and degradation results showed good removal efficiency for the reedbed systems, combined with natural attenuation in the groundwater. Full article

With the widespread application of automatic fire alarm systems in various types of buildings, the problem of fire false alarms has gradually become prominent, which not only causes resource waste, but also may reduce users’ trust in the alarm system, thereby affecting the efficiency of emergency response in actual fires. According to data from a certain fire cloud platform, 99.85% of the suspected fires predicted by its system are false alarms. Although existing models can recognize most fire accidents, the accuracy of fire alarm recognition is only 0.15%, due to loose judgment logic, which still requires a large amount of manpower to verify alarms. This article analyzes a large amount of false alarm data and explores the main causes of false alarms, including environmental interference, equipment failure, and improper human operation. By using a fire dynamics simulator (FDS) to establish fire simulation models under different data settings, horizontal and vertical multi-scene fire simulation data are obtained. The study combines simulation and platform data to form a fire and false alarm dataset using a one-dimensional convolutional neural network (1D-CNN) and deep neural network (DNN) deep learning techniques to learn the deductive rules of the fire scene, establish a two-stage judgment model, and gradually, accurately, judge the results. By quantifying the precision, recall, and F1 score of the model, a deep learning model designed to accurately identify genuine fire alarms while filtering out false ones is proposed that can significantly reduce the false alarm rate. The results indicate that the model can identify 1705 false alarms out of 2255 highly suspected true alarms identified by existing systems in multiple practical scenarios and eliminate 75.61% of false positive alarms. On the premise of ensuring an authenticity recognition rate greater than 98%, the accuracy of fire alarm recognition increased from 0.15% to 28.85%, which will significantly reduce the workload of staff verifying alerts, and has good practical value. Full article

Stochastic Subspace Identification (SSI) theory offers the distinct advantage of extracting modal parameters directly from operational ambient excitations without requiring artificial force, ensuring completely true boundary conditions and providing extensive field measurement data. In this study, we systematically investigate the operational modal characteristics of Electric Multiple Units (EMUs) in the Chinese high-speed railway network under multi-dimensional coupling conditions, including wide speed ranges, axle load perturbations, air spring faults, and coupled operation. The results reveal that while car body modal frequencies remain largely insensitive to operating speed—indicating negligible effects of aerodynamic stiffness—they exhibit distinct sensitivities to mass and boundary variations. Specifically, an increase in axle load induces a significant attenuation (exceeding 5%) in low-order vertical bending frequencies, conforming to the dynamic mass law. Conversely, air spring deflation triggers a sharp increase in boundary stiffness, resulting in a 13.6% surge in torsional modal frequency, which serves as a critical indicator for fault diagnosis. Furthermore, coupled operation is found to primarily enhance system damping. Based on these findings, we establish a “condition-modal” vehicle sensitivity matrix, quantifying dynamic evolution mechanisms under complex boundaries and providing a vital baseline for monitoring the structural health of railway vehicles and conducting intelligent maintenance. Full article

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

Against the backdrop of a gradual shift in the focus of cultural heritage (CH) conservation and utilization toward the integrated system formed by CH and its surrounding environment as well as regional systems, research on the coordinated protection of nature and culture to promote regional high-quality development has become a new trend. However, systematic summaries of the spatial–temporal distribution of CH in cross-regional typical geomorphic units at the river basin scale and their correlation with the natural environment remain insufficient. This study takes 387 Cultural Relics Protection Units in the Three Gorges of the Yangtze River (the Three Gorges region) as the research objects, utilizing GIS spatial analysis technology to examine the impact of the natural environment on CH across different periods and types. The theory of time-depth is introduced to reveal the layering mechanisms and underlying cultural logics. Coupled with the Minimum Cumulative Resistance (MCR) model, this study constructs a cultural corridor network and proposes spatial planning strategies. The findings are as follows: (1) The absolute core area for the distribution of CH across all periods remains the gentle slope zone near the river, characterized by elevations below 500 m, slopes within 25°, and distances from water systems within 1 km. However, the adaptive scope exhibits a diachronic evolution from core accumulation to peripheral expansion. (2) Different types of CH exhibited distinct natural adaptation strategies and vertical accumulation. Settlement Sites in the Before Qin Dynasty Period formed the foundational layer of survival rationality, while Ordinary Tombs in the Qin–Yuan Dynasty Period reinforced sedentism. Ancient Architecture in the Ming–Qing Dynasty Period underwent a transformation from “adapting to nature” to “reconstructing nature” as a product of environmental construction. Modern and Contemporary Significant Historical Sites and Representative Buildings in the After Qing Dynasty Period are characterized by a ruptured insertion on steep slopes, inscribing revolutionary memory onto space. The main stream of the Yangtze River serves as the core area of continuous deposition, while the extremely steep slopes form a distinctive stratigraphic accumulation of precipitous terrain. (3) Based on these distribution patterns, the study further proposes a spatial framework for CH called “One Corridor, Three Wings.” This framework uses the main stream of the Yangtze River as the spatial–temporal axis, linking the four core overlapping nodes of Fengjie, Wushan, Badong, and Xiling, supplemented by three secondary cultural clusters of the red heritage sites in southern Badong, the ancient town along the Daning River in Wushan, and the fortress sites in the Xiling–Yiling area. This research not only reveals the evolutionary path of CH in the Three Gorges region, but also provides a scientific basis for the systematic conservation and differentiated utilization of regional CH. Furthermore, it serves as a planning foundation and strategic reference for planning the Yangtze River National Cultural Park, as well as for the integrated preservation and utilization of river basin CH and linear CH with the aim of coordinated natural and cultural conservation. Full article

This paper presents the design, optimization, and performance evaluation of a Satellite-Based Augmentation System (SBAS) ground segment tailored to Colombia’s air navigation infrastructure, with emphasis on ionospheric anomalies in equatorial latitudes. The configuration comprises six Reference Stations (RIMS), strategically sited via geometric dilution of precision (GDOP) minimization and airspace demand models from ADS-B data. A simulation suite—integrating STK^®, Radio Mobile™, and Stanford-ESA certified monitors—quantifies service volume, link margins, and protection level compliance. Ionospheric threat characterization uses regional scintillation datasets (σln ≈ 0.36, ROTI₉₅ ≈ 85 mm/km), informing GIVE inflation and dual-frequency pseudorange integrity validation. Simulations confirm the system sustains ≥ 99.8% APV-I availability over the CAR/SAM FIR, with Horizontal and Vertical Protection Levels (HPL/VPL) bounded below 28 m and 46 m. Uplink integrity and GEO broadcast continuity are modelled under worst-case masking and multipath, confirming ICAO Annex 10 SARPs compliance. The architecture achieves a high performance-to-cost ratio, enabling nationwide SBAS coverage with a 65% cost reduction versus legacy navaids. The system is forward-compatible with dual-frequency multi-constellation SBAS (DFMC), supporting future APV-II scalability. These results position Colombia as a regional node for GNSS augmentation, fostering safety, efficiency, and procedural harmonization. Full article

With the considerable number of low-dose CT examinations performed in lung cancer screening, variations in participant positioning, scan direction, or localiser angle are likely to occur in practice. These variations are known to affect automatic tube current modulation (ATCM) operation, yet organ-specific dose implications across CT models remain unknown. Therefore, this simulation study systematically characterised the effect of the aforementioned variations. Using the Alderson RANDO phantom, ATCM profiles were established on CT scanners from four major vendors (GE, Siemens, Canon, Philips) after introducing vertical and lateral mispositioning, craniocaudal and caudocranial scan directions, and varying localiser projection angles. Additionally, off-centre positioning and scan direction changes preceded by either a single posteroanterior (PA) or dual (PA+lateral) localiser were evaluated. Doses to the lungs, heart, thyroid, liver, and breasts were calculated from Monte Carlo simulations of each setup for 32 patient-specific voxel models. The results demonstrate statistically significant and scanner-dependent dose variations. PA localisers generally produced the highest organ doses. However, on the Philips system, organ dose increases of at least 50% were observed after the lateral projection angle. GE and Siemens scanners showed pronounced dose increases following downward mispositioning with a single PA localiser (18–50% and 5–25%, respectively), an effect largely mitigated by adding a lateral localiser. Canon and Philips scanners exhibited generally stable ATCM behaviour after vertical off-centring, although Canon showed notable dose increases upon lateral mispositioning, with dose increases up to 37.5% and 34% after a single PA or dual localiser, respectively. Variations in scan direction displayed highly model- and organ-dependent effects. Dose deviations were largely mitigated after dual localisers for the GE, Canon, and Philips scanner types. Here, organ dose differences were within an absolute range of 10%, indicating that a change in scan direction preceded by a dual localiser can reduce extreme dose deviations. Remarkably, no significant difference was observed solely for the Siemens scanner when combined with a dual localiser, as lung, heart, breast, and liver doses remained significantly (between 20 and 35%) lower when scanning craniocaudally, whereas the thyroid dose in this setup remained considerably higher (up to 20% mean increase). Ultimately, findings indicate that seemingly minor protocol deviations can lead to significant underestimation of anticipated organ-specific doses associated with lung cancer screening. Scanner-specific optimisation, supported by medical physics expertise, is therefore essential. Full article

Traditional passive hydraulic dampers face the challenges of extended design cycles, inefficient parameter matching, and fixed performance, limiting their adaptability. This paper proposes an integrated solution that combines inverse parametric design with active, continuously adjustable damping. First, a high-fidelity nonlinear model is developed based on valve plate elasticity and multi-valve coupling dynamics, achieving a simulation error of ≤4%. An improved genetic algorithm is then designed to inversely optimize five key parameters. This optimization reduces the deviation between the prototype’s damping force–velocity characteristics and the target curve to ≤3% and shortens the design cycle by approximately 40%. Building on this foundation, a pilot-operated electro-hydraulic proportional relief valve is integrated to enable continuous damping adjustment. Co-simulation using AMESim2404 and MatlabSimulinkR2022 reveals the influence of solenoid valve parameters on damping characteristics and calibrates the current–damping force mapping. A co-simulation of a skyhook-controlled quarter-vehicle model demonstrates that the semi-active suspension system reduces the root mean square (RMS) of vertical body acceleration by 21.7%, indicating a significant theoretical improvement in ride comfort. This study establishes a complete technical pathway of “modeling → inverse optimization → integration → verification,” providing an efficient and viable core component solution for intelligent suspension systems. Full article

Colonial historic city centers represent a paradigmatic challenge for modern road safety, as they are characterized by narrow streets originally designed for carriage and pedestrian traffic. This research presents ADAS-TSR, a deep learning-based advanced driver assistance system for vertical traffic sign detection with voice alerts, specifically designed for the Historic Center of Ayacucho, Peru, which is located at 2761 m a.s.l. An original dataset comprising 2250 images with 2450 instances corresponding to 14 sign classes according to Peruvian regulations was constructed. The dataset was captured under real operational conditions, including deteriorated, partially occluded, and vehicle impact-deformed signage. A comprehensive multi-model benchmark experiment was conducted, comparing four CNN-based detectors (YOLOv8m, YOLO11n, YOLO26n, YOLO26s) and one transformer-based detector (RT-DETR-l) spanning both classical and state-of-the-art architectures released through January 2026. YOLO26s achieved the best overall performance, with an mAP@0.5 of 0.994 and mAP@0.5:0.95 of 0.989 while using only 9.5 M parameters. YOLO11n matched the performance of YOLOv8m with 10× fewer parameters (2.6 M vs. 25.9 M). Uncertainty analysis revealed that modern architectures exhibit significantly higher prediction confidence (mean > 0.90) compared to YOLOv8m (0.82), and fairness analysis confirmed equitable detection across all 14 classes (Gini < 0.002). A voice alert system with five priority levels and rule-based temporal filtering for detection stabilization was implemented. Validation across five urban circuits spanning 14.11 km demonstrated a detection rate of 94.7% with a 73% reduction in redundant alerts. Full article

Against the macro-background of balancing development and food security strategies, China has implemented a land-use regulation system centered on farmland protection. However, the economic impacts of such regulation lack sufficient quantitative evaluation. Using farmland retention targets at the county-level in the administrative region and combining them with relevant data, this study employs an Intensity Difference-in-Differences (Intensity DID) approach to examine how land-use regulation affects county-level economic growth and convergence. The findings reveal a U-shaped relationship between land-use regulation and county-level economic growth, suggesting that, at the current stage, the intensity of land-use regulation generally promotes economic growth. Heterogeneity analysis further indicates that county economies in major grain production areas (MGPAs) and main grain-producing counties (MGPCs) experience stronger negative constraints related to the policy, while MGPCs in non-major grain production areas (non-MGPAs) are most sensitive to land-use regulation. China’s county economies exhibit convergence; however, land-use regulation may reduce the growth rate of counties that were underdeveloped in the base period, thereby widening inter-county development disparities. This divergence is manifested in the lack of convergence between the clubs of MGPCs and non-MGPCs. Mechanism analysis suggests that differences in industrial structure, capital investment, and fiscal expenditure constitute the key focal points for addressing the issue. Policy implications indicate that China should strengthen land-use regulation on the premise of rationally determining the functions and scale of various land types, continue to advance market-oriented reforms of land factors, improve the vertical and horizontal interest compensation mechanism for MGPAs, and stimulate the endogenous development momentum of these regions. Full article

Aiming at the challenge of simultaneously controlling ride comfort and wheel grounding performance for mining dump trucks, this paper proposes a multi-dimensional synergistic optimization control (MDSOC) strategy based on model predictive control (MPC) for active hydro-pneumatic suspension. First, an accurate hydro-pneumatic suspension and hinged mining truck full-vehicle-dynamics model is established, and the model accuracy is validated through actual vehicle testing. Subsequently, an MDSOC-MPC for active hydro-pneumatic suspension is constructed to minimize the mean square root of the three-axis acceleration of the body, pitch angle, roll angle, and wheel dynamic tire load. Comparative analysis is performed with traditional single-MPC longitudinal, lateral, and vertical control, and the simulation results showed: under emergency braking conditions, the root mean square (RMS) value of the pitch angle is reduced by 18.2%; under single and double-shift conditions, the RMS values of the roll angle are reduced by 40.4% and 30%, respectively; under D-class random road, the RMS values of the longitudinal, lateral, and vertical body acceleration are significantly reduced by 22%, 21.5%, and 21.2%, respectively, while the RMS values of pitch angle and roll angle are reduced by 22.5%, and 20.2%, respectively, systematically improving riding comfort, vehicle wheel contact, and driving safety. This study provides a theoretical basis and feasible engineering methods for the active control of hydro-pneumatic suspension systems in heavy engineering vehicles. Full article

The Sichuan Basin serves as a key arena for ultra-deep natural gas exploration. The Nanhuan System Gucheng Formation, characterized by its ancient geological age and great burial depth, lacks almost any drilling data within the basin interior, and its sedimentary features and natural gas potential remain unstudied. Based on outcrop sections of the Nanhuan Gucheng Formation along the northern margin of the Sichuan Basin, sedimentological and hydrocarbon reservoir characteristics were analyzed. The study reveals: ① The lower Gucheng Formation at the Chenkou Yuyang section comprises three lithofacies: deformed-bedding conglomeratic sandstone, massive-bedded medium sandstone, and dark-gray horizontally-bedded mudstone, interpreted as deposits of turbidity channels, turbidite fan lobes, and deep-water shelf mud, respectively; ② The turbidity channel and fan sandstones exhibit dissolution pores, with porosities ranging from 8% to 12%, representing favorable reservoirs with a cumulative thickness exceeding 40 m. The deep-water shelf mud shows TOC values between 0.8% and 1.5%, serving as favorable source rocks with a cumulative thickness over 30 m. These two units are interbedded, forming an effective source-reservoir assemblage; ③ Based on the west–east outcrop transect (Zhenba Xiaoyangba, Chenkou Yuyang, and Mahuang Gou sections), the thickness of the Gucheng Formation displays a thin–thick–thin variation, interpreted as reflecting a sedimentary transition from shallow-water shelf delta to deep-water shelf/turbidite systems and back to shallow-water shelf deposits. A rift depositional model with a gentle western slope and steep eastern slope is proposed. In deep-water shelf areas, turbidite sandstone reservoirs are vertically interbedded with shelf mudstone source rocks, while in shallow-water shelf areas, deltaic sandstone reservoirs are laterally connected to source rocks. Spatially, this constitutes a hydrocarbon distribution pattern characterized by “vertical stacking and lateral connectivity,” providing valuable insights for ultra-deep natural gas exploration in the Sichuan Basin. Full article

The constituent elements of source-to-sink systems and their coupling relationships are key controls on the development of sedimentary systems and the spatial distribution of sand bodies. Taking the Paleogene strata in the southern Laizhouwan Sag of the Bohai Bay Basin as a case study, we integrate drilling, logging, core, thin-section, and high-resolution 3D seismic data to quantitatively characterize basement lithology and effective provenance area, drainage-unit subdivision, types and scales of sediment transport pathways, and geometric parameters of depositional fans, within a source-to-sink analytical framework. The results show that: (1) Two distinct provenance types are developed in the southern Laizhouwan Sag, including Proterozoic granitic–gneissic basement and Mesozoic volcanic–clastic basement. These provenance types exhibit pronounced differences in effective source area, vertical relief, and drainage-network configuration across different sequence stages. (2) Two main categories of sediment transport pathways are identified, namely paleo-valleys and fault-controlled troughs. V-shaped, U-shaped, and W-shaped paleo-valleys show systematic morphological transitions along topographic gradients. The width-to-depth ratio of transport channels exerts a significant control on depositional fan scale, with U-shaped valleys exhibiting the highest sediment transport efficiency. Finally, (3) the depositional domain is dominated by near-source fan-delta systems, whose scale shows a strong positive correlation with effective provenance area and transport-channel morphology. Overall, the southern Laizhouwan Sag is characterized by a typical fault-controlled, steep-slope source-to-sink system, in which sedimentary system distribution is jointly governed by effective provenance area, sediment transport pathway geometry, and fault-related slope-break zones. This study provides a quantitative example and methodological reference for source-to-sink system characterization and prediction of favorable sand body distribution in continental rift basins. Full article

Tunnel lighting systems serving pedestrian and vehicular traffic must simultaneously satisfy visual performance requirements and energy efficiency constraints. This study investigates the optimization of tunnel lighting design using a sustainable engineering approach based on Response Surface Methodology (RSM) and Specific Lighting Energy Consumption (SLEC). Software-assisted lighting simulations were performed for two tunnel geometries—straight and double-curved—and horizontal (Eh) and vertical (Ev) illuminance levels were evaluated at five representative locations. The resulting data were used to construct RSM-based predictive models and to assess energy performance through SLEC. The effects of mounting height, luminaire spacing, luminous flux, number of luminaires, and tunnel type were systematically analyzed. The results demonstrate that luminaire spacing is the dominant parameter influencing illuminance levels and energy consumption. An optimal configuration consisting of a 12 m luminaire spacing, 5 m mounting height, and 10,000–12,000 lm luminous flux achieved a favorable balance between lighting quality and energy efficiency. Additionally, straight tunnels exhibited higher illuminance uniformity at shorter spacings, whereas curved tunnels showed improved performance under wider spacing conditions. The proposed RSM–SLEC framework provides a robust, data-driven methodology for sustainable tunnel lighting design without compromising safety or visual comfort. Full article