Search Results (1,115)

With the increasing importance of securing quantum communication networks, practical and robust entity authentication is a critical requirement. Accordingly, we propose and experimentally validate a quantum entity authentication (QEA) protocol specifically designed for integration with BB84-type quantum key distribution (QKD) workflows and existing terminal architectures. We analyze the protocol’s security against intercept–resend man-in-the-middle (MitM) impersonation, showing that an unauthenticated adversary induces a characteristic 25% correlation error and that the rejection probability approaches unity as the number of detected authentication events increases. For practical realization, the protocol is deployed using weak coherent pulses (WCPs) with decoy-state estimation to bound single-photon contributions and mitigate photon-number-splitting (PNS)-enabled leakage. The system is demonstrated over a field-deployed fiber link of approximately 20 km with ~8 dB optical loss using signal/decoy intensities of ~0.5/~0.15 and sending probabilities 0.88/0.10/0.02 (signal/decoy/vacuum). Across both verification directions, stable operation is observed with quantum bit error rate (QBER) typically fluctuating between 1% and 4% while the sifted key rate remains constant over time. These results provide an experimental basis for integrating physical-layer entity authentication into deployed quantum communication networks. Full article

Accurate urban expansion mapping in dryland environments is essential for sustainable planning, infrastructure management, and heritage-sensitive development, yet it remains methodologically challenging because built-up surfaces often exhibit strong spectral similarity to bright bare soils. This study comparatively evaluates three widely used urban mapping approaches in Diriyah, Saudi Arabia, a rapidly transforming heritage district of high relevance to Saudi Vision 2030: the Global Human Settlement Layer (GHSL), the Normalized Difference Built-up Index (NDBI), and unsupervised k-means classification. Built-up extent was mapped for 2015, 2020, and 2025, and method performance was assessed using 150 stratified reference points interpreted from high-resolution imagery. The results reveal substantial quantitative differences among methods. GHSL produced the most conservative estimates of urban extent (2.80, 4.94, and 5.31 km²), while NDBI and unsupervised classification generated much larger and less realistic built-up areas due to spectral confusion with bright bare soil. Accuracy assessment confirmed the superiority of GHSL, which achieved the highest overall accuracy (0.88) and Kappa coefficient (0.83), compared with NDBI (0.53; 0.41) and unsupervised classification (0.61; 0.50). To support integrative interpretation, the study also developed a Hybrid Built-up Detection Model (HBDM), which combines the three outputs into a continuous urban intensity layer that helps distinguish persistent urban cores from uncertain transition zones. The findings demonstrate that conservative global built-up products provide a more reliable baseline than index-based or unsupervised methods in bright-soil dryland settings. More broadly, the study offers practical methodological guidance for urban monitoring and sustainable land management in desert cities undergoing rapid transformation under large-scale development agendas such as Saudi Vision 2030. Full article

Fifth-generation (5G) networks enable railway digitalization but face signal degradation challenges in high-mobility environments. While the existing literature attributes degradation primarily to Doppler frequency shifts, this study presents empirical evidence challenging this paradigm. Analysis of 13.7 million 5G New Radio measurements across 370 km of Estonian railway reveals that visible cell density, not velocity, dominates signal quality degradation. Nine geographic hotspots exhibit 5.4–18.0 dB degradation at moderate velocities (54–66 km/h, mean 60.2 km/h) with zero high-speed measurements, excluding the Doppler effect as the reason behind service quality degradation. Cell complexity demonstrates a 3.25× stronger correlation with degradation (r = −0.390) than velocity (r = −0.120), consistent with automatic frequency control tracking instability under high cell ID churn rates (40–115 visible cells per location), though direct confirmation of this mechanism requires access to internal modem frequency-lock state data. Frequency band analysis shows that 700 MHz is optimal at 98.1% of locations, with a 19 dB advantage over 3.5 GHz. Degradation mechanism decomposition reveals within-cell effects (60%, 7.85 dB) and handover boundary effects (40%, 2–6 dB). The findings challenge velocity-centric optimization paradigms and recommend network planning focused on cell overlap reduction rather than Doppler compensation enhancement. Practical recommendations include 700 MHz prioritization, handover parameter optimization, and geographic targeting of identified hotspots for European railway 5G deployment. Full article

This study investigates how asphalt mixture type influences the degradation of pavement-marking retroreflectivity and luminance contrast under real operational conditions on Israeli intercity roads. Field measurements were collected along 65.1 km of roadway constructed with three asphalt mixtures: basalt dense-graded concrete (Basalt DCG), basalt stone mastic asphalt (Basalt SMA), and basalt–dolomite dense-graded concrete (Zebra DCG). Linear degradation models provided the best representation of retroreflectivity decay (R² = 0.63). Results show that asphalt mixture type significantly affects initial retroreflectivity, contrast, and effective service life of left-side white paint markings. Markings applied on Basalt DCG exhibited initial retroreflectivity values up to 1.6–1.9 times higher and maintained acceptable visibility for approximately 7–8 months, compared with about 3 months on Zebra DCG under comparable conditions. Traffic volume was not a statistically significant predictor, indicating that degradation is dominated by time-dependent material and optical aging processes. Pavement background reflectivity and its evolution play a critical role in contrast degradation. The results demonstrate that asphalt mixture selection can reduce repainting frequency by approximately 10–15%, highlighting asphalt mixture choice as a practical and previously underrecognized lever for improving pavement-marking durability and long-term visibility. Full article

To address natural aggregate scarcity and improve the high-value utilization of Reclaimed Asphalt Pavement (RAP), this study proposes a steel slag–RAP hot recycled asphalt mixture (SSRM) as a sustainable alternative to conventional limestone–RAP mixtures (RM). Unlike previous studies mainly focusing on performance verification, an integrated environmental–economic evaluation framework was developed based on real highway expansion project data under a “cradle-to-gate” boundary and incorporating transportation distance thresholds. SSRM containing 50% RAP and 23% steel slag as coarse aggregate replacement was evaluated through rutting, semi-circular bending (SCB), freeze–thaw splitting (TSR), and skid resistance tests. Compared with RM, SSRM exhibited 14–16% higher dynamic stability and 20–25% higher fracture energy at −10 °C, along with improved moisture stability and skid resistance, mainly attributed to the rough and alkaline characteristics of steel slag enhancing adhesion and aggregate interlocking. Life-cycle assessment (GWP100) and cost analysis indicate that SSRM reduces carbon emissions by 10–11% relative to RM and about 40% compared with conventional virgin mixtures, while initial construction costs decrease by 9–10%. Transportation sensitivity analysis identifies equal-emission and equal-cost thresholds of approximately 590 km and 380 km, respectively. Within typical material supply radii (300–400 km), SSRM demonstrates both environmental and economic advantages, providing a practical framework for low-carbon material selection in highway construction. Full article

Reducing the life-cycle CO₂ emissions of electric vehicle (EV) traction motors requires a comprehensive evaluation of material selection, magnet configuration, and structural design. In this study, six motors—including a benchmark NdFeB-based PMSM—are designed under unified constraints of identical outer diameter, ampere-turns, and target torque (163 Nm), enabling a fair comparison of environmental performance. Electromagnetic field simulations are conducted to optimize each design, and life-cycle CO₂ emissions are quantified using emission factors from IEEJ-IAS and standard material databases. The results show that manufacturing-stage emissions vary significantly depending on magnet and winding materials: the benchmark PMSM exhibits the highest manufacturing CO₂ (42.1 kg-CO₂), while the rare-earth-free PMaSyn.RM achieves the lowest value (28.4 kg-CO₂). In contrast, use-stage emissions over 150,000 km are dominated by motor efficiency, ranging from 1820 kg-CO₂ (PMSM-Cu) to 2030 kg-CO₂ (Al-wound PMSM). Consequently, the total life-cycle CO₂ spans from 1848 kg-CO₂ (PMaSyn.RM) to 2072 kg-CO₂ (Al-wound PMSM), indicating that rare-earth-free motors minimize manufacturing impact, whereas high-efficiency PMSMs reduce use-stage emissions. Furthermore, the study evaluates the practical feasibility of aluminum windings and rare-earth-free designs, identifying structural requirements such as dual-rotor configurations for aluminum conductors and flux-barrier optimization for ferrite-based motors. These findings provide quantitative insights into the trade-offs between material sustainability and operational efficiency, offering guidance for future EV motor development toward carbon neutrality. Full article

Background: Wearable sensors and global positioning systems (GPS) can enable objective monitoring of training loads in outdoor endurance sports. In biathlons, comparing training characteristics across developmental stages can help identify structural gaps and support evidence-informed progression within long-term athlete development (LTAD). This study aimed to quantitatively compare the annual training characteristics of Korean male biathlon national team (NT) and university (UNV) athletes. Methods: Annual physical training data (2022–2024) from NT (n = 6) and UNV (n = 6) athletes were collected using Catapult Vector S7 GPS devices and Polar H10 heart rate monitors. Training volume, intensity distribution (zones 1–3 based on %HRmax), modality (skiing vs. running), and periodization were compared using Mann–Whitney U tests with rank-biserial correlation (r_rb). Results: NT athletes accumulated a higher annual training time and distance than UNV athletes (812 vs. 606 h; 6359 vs. 4130 km; p = 0.002, r_rb = 1.000 for both). The NT athletes spent a lower proportion of time on low-intensity training and a higher proportion on mid and high intensities than UNV athletes (p ≤ 0.015). During high-intensity training, NT athletes maintained a higher proportion of ski-specific training, whereas UNV athletes relied more on running (skiing: 78.5% vs. 46.4%; running: 21.5% vs. 53.6%; both p < 0.001, r_rb = 1.000). The UNV group also showed a more concentrated structure during competition periods than NT athletes (COMP: 28.3% vs. 14.6%; p < 0.05). The absolute annual strength training time did not differ, but UNV athletes showed a higher strength ratio (23.3% vs. 16.8%; p < 0.001, r_rb = 1.000). Conclusion: UNV athletes exhibited a lower total volume, more low-intensity-skewed distribution, and reduced ski-specific exposure during high-intensity training compared with NT athletes. These observed structural gaps can provide empirical benchmarks that may help coaches plan stage-appropriate progression, and they illustrate the practical value of GPS- and wearable-based monitoring for identifying training divergences across developmental stages. Full article

Soil erosion on the Yunnan–Guizhou Plateau (YGP) has a significant impact on the water sources and ecological safety of Southeast Asia and South China. With the influence of climate change, this erosion has been altered, which will create uncertainty regarding soil erosion management and social development in China and Southeast Asia. However, existing research still lacks simulations of soil erosion in large-scale regions, as well as a systematic understanding of the spatiotemporal characteristics of future soil erosion under climate change. Therefore, a coupled model of the Shared Socioeconomic Pathways (SSPs) and the Revised Universal Soil Loss Equation (RUSLE) at the regional scale of the YGP is proposed in this study. By analyzing the erosion patterns in the YGP, this research determines the optimal future scenario and corresponding mitigation strategies, thereby offering a localized practical reference for soil erosion control in the YGP and its alignment with the UN SDGs. The results show the following: (i) Temporally, soil erosion on the YGP will improve in the future. The overall soil erosion moduli of the YGP decrease by 196.86, 367.03, and 391.72 t/(km²·a) under the scenarios of SSPs1-1.9, SSPs2-4.5, and SPPs5-8.5, respectively. (ii) Spatially, soil erosion in the southwestern and central-northern parts of the YGP will be significantly improved in the future. The soil erosion moduli of the karstic and non-karstic areas gradually become close to each other, with the difference in soil erosion moduli between them in SSPs1-1.9, SSPs2-4.5, and SSPs5-8.5 being reduced from 671.65 t/(km²·a) to 623.79, 592.21, and 611.92 t/(km²·a), respectively. (iii) Among the different SSP scenarios, the SSPs2-4.5 scenario aligns most closely with the principles of sustainable development, making it the most desirable pathway. To ensure the long-term effectiveness of soil erosion control under changing climate and socioeconomic conditions, future strategies should take the SSPs2-4.5 scenario as a core reference and implement resilient portfolios of mitigation measures. Full article

Assessing and optimizing regional ecological networks is critical for mitigating fragmentation-driven ecological risks and informing evidence-based territorial spatial planning in China. In this study, we developed a comprehensive evaluation framework integrating ecosystem services, ecological sensitivity, and landscape connectivity to identify ecological sources in Anyang City, China. We then extracted ecological corridors and nodes using circuit theory and constructed the city’s ecological network. Notably, we applied complex network theory combined with topological robustness analysis for optimization to enhance network stability. The analysis identified 43 ecological sources (820.72 km²; 11.16% of the region), predominantly distributed in western Anyang. A total of 82 corridors (460.35 km), 62 pinch points, and 120 barrier points were mapped—primarily in the west, revealing critical connectivity deficits. Network optimization through the addition of 10 strategic corridors significantly enhanced structural balance and functionality, with average degree, closeness centrality, clustering coefficient, eigenvector centrality, and graph density increasing by 5.55–12.19%, and their standard deviations decreasing by an average of 19.32%. Global efficiency (+8.74%), the largest connected component ratio (+0.73%), and node/edge recovery robustness (+17.44%/+18.08%) also improved markedly, confirming greater connectivity and resilience. Our methodology comprehensively integrates ecosystem functional services, disturbance resistance, and spatial structural stability, providing a practical reference for the construction and optimization of regional ecological networks in mountainous–plain transition zones of China. Full article

The regularity of the catenary system and the stability of pantograph–catenary interaction are crucial for ensuring continuous and stable current collection quality in high-speed trains. Given that the dropper is a key suspension component within the catenary, the state of service integrity directly determines the regularity of, and dynamics within, the pantograph–catenary system. However, under long-term alternating loads and environmental influences, the dropper inevitably suffers damage due to strand fracture. The geometric regularity of the catenary is consequently disrupted, and the current collection quality of trains can deteriorate. While substantial efforts have been devoted to the study of pantograph–catenary dynamics under ideal or intact dropper conditions, research on current collection quality when the dropper has different types of damage remains insufficiently understood. This study focuses on the practical operational situation of high-speed railways, investigating the impact of dropper damage on current collection quality. Firstly, based on the pantograph–catenary parameters of an actual line, a dynamic model capable of simulating different types of dropper damage was built. Secondly, the current contact quality under various types of damage was explored in detail by several time-domain statistical features. Finally, within the typical speed range of 250 km/h to 350 km/h, the evolution of pantograph–catenary dynamic behavior under the combined effects of operating speed and dropper damage was analyzed, providing a theoretical basis for the reliable assessment of pantograph–catenary current collection quality and the formulation of stable operation and maintenance strategies. Full article

On heavy-haul railways, ballast fouling progressively reduces ballast resistance, which in turn degrades the electrical performance of track circuits. To address this cascading issue, we propose a ground-penetrating radar (GPR)-based method for assessing ballast bed conditions and inverting ballast resistance $R_b$ continuously along the track. First, by integrating transmission line theory with Archie’s law, this paper establishes the mechanistic link between microscale dielectric deterioration of the fouled ballast and the macroscale electrical parameters of the track circuit. Next, we build a full-wave electromagnetic simulation model to extract two key GPR signal features: time-domain relative energy attenuation and frequency-domain spectral redshift. Recognizing the limitations of single-feature analysis, we introduce an adaptive weight-based multi-feature fusion algorithm to construct a comprehensive fouling index that quantifies the physical state of the ballast. Based on this index, we develop a quantitative mapping model between the fouling index (FI) and $R_b$, enabling continuous inversion of ballast resistance over the entire line. Our results show excellent agreement between the inverted $R_b$ profile and the theoretical ground truth, with the FI alarm threshold precisely corresponding to the critical safety limit of $R_b$ = 0.5 Ω km. This approach effectively overcomes the limitations of traditional discrete monitoring and provides a practical tool for predictive maintenance of track circuits. Full article

Against the backdrop of coordinated advancement in new urbanization and rural revitalization strategies, the integration of urban and rural areas serves as a core approach to dismantling the urban–rural dichotomy and driving high-quality regional development. The enabling effects of its policy implementation on regional sustainable development have garnered significant attention. As pivotal conduits where urban and rural elements converge, peri-urban fringe zones have emerged as the primary arena for policy implementation and impact realization. Using panel data from 268 prefecture-level and above cities in China from 2015 to 2024 as the sample, this study treats the establishment of urban–rural integration pilot zones as a quasi-natural experiment. Employing a multi-period Difference-in-Differences model, instrumental variables method, and spatial econometric model, it systematically investigates the impact effects, operational mechanisms, heterogeneous characteristics, and spatial spillover effects of urban–rural integration policies on regional sustainable development. Findings reveal that urban–rural integration policies significantly promote regional sustainable development. This conclusion remains robust after endogeneity treatment and stability tests, with policies demonstrating stronger enabling effects on ecological sustainability than on economic and social sustainability, forming a development pattern characterized by “ecological priority and multidimensional coordination”. Policies achieve synergistic enhancement of regional economic, ecological, and social sustainability through three pathways: optimizing urban–rural factor allocation, establishing ecological co-governance systems, and advancing equitable public services. Policy effects exhibit significant heterogeneity: the stronger the urban baseline conditions, the more pronounced the policy’s enabling effect, while excessive population concentration exerts a marginal negative impact on ecological sustainability. Urban–rural integration policies generate a significant positive spatial spillover effect, accounting for 38.9% of the total effect. This spillover gradually diminishes with increasing distance within a 120 km radius, with geographic distance and administrative barriers serving as core constraints. This study provides empirical insights and practical pathways for optimizing urban–rural integration policy design and advancing regional sustainable development. Full article

The global demand for high-quality food is rising due to the increasing population, necessitating intensive farming practices that often involve the extensive use of pesticides, which can accumulate in soils and enter the food chain. This study explores the use of synthesized and commercial graphenes for the removal of kresoxim-methyl (KM), a common strobilurin fungicide, from soil. Adding only 1 wt% of graphene to soil enhanced its partitioning capacity from about 4.77 mg/g for unamended soil to 9.57 mg/g, indicating effective immobilization and reduced environmental risk. The adsorption efficacy was notably higher in materials rich in oxygen-containing functional groups and with a large surface area, highlighting the significance of surface characteristics and porosity. The adsorption followed pseudo-second-order kinetics, underscoring the importance of surface heterogeneity in KM adsorption. Full article

Quantum Encryption in Phase Space (QEPS) is a physical-layer encryption framework that harnesses the quantum-mechanical properties of coherent states to secure optical communications against both classical and quantum computational threats. By applying randomized phase shifts, displacements, or their dynamic combinations—implemented as unitary transformations in phase space—QEPS disrupts the phase reference essential for coherent detection, establishing aphase synchronization barrier. This review synthesizes the theoretical foundations, security mechanisms, and experimental progress of the QEPS framework, encompassing its three principal variants: the round-trip Quantum Public Key Envelope (QPKE) protocol—a public-key-like scheme built upon phase randomization (QEPS-p), the symmetric phase-only QEPS-p, and the displacement-based QEPS-d. Experimental validations demonstrate that authorized users achieve bit-error rates (BERs) below the forward-error-correction threshold, whereas eavesdroppers are confined to BERs near 50%, equivalent to random guessing—all while utilizing standard coherent optical transceivers at data rates up to 200 Gb/s over 80 km of fiber. We further examine QEPS’s robustness to channel impairments, its seamless compatibility with existing digital signal processing (DSP) pipelines, and its distinctive position within the post-quantum cryptography landscape. Finally, we outline key challenges and future research directions toward deploying QEPS as a practical, quantum-resistant security layer for next-generation optical networks. Full article

Gait parameters are commonly reported, but their stability over durations representative of a typical continuous run remains poorly understood. This study investigated the stability and temporal structure of key spatiotemporal and kinetic parameters during a 30 min easy-paced treadmill run (13 km∙h⁻¹) while participants wore familiar and unfamiliar every day running shoes. Step-level data were analysed across the full time series and in sequential 1 min epochs to determine how long each parameter took to reach practical stability and whether this differed between shoe conditions. Approximately 2450 steps were analysed per condition. Within-participant variability was low (CV < 2.5%) for all parameters and conditions except for peak impact force (CV = 6.9–7.0%) and average loading rate (CV = 8.4–8.7%). Detrended fluctuation analysis (DFA-α) indicated persistent temporal structure for stride duration, swing time, and active peak force, whereas loading-phase kinetics showed weak long-range dependence. No significant differences were observed between shoe conditions for variability or temporal structure, although ground contact time was significantly longer when participants wore unfamiliar shoes. Practical windows of stability relative to each participant’s 30 min mean ranged from 11 to 17 min for spatiotemporal variables, 9 to 17 min for active peak force, and within the first minute for impact-related parameters and impulse. These findings indicate that studies examining spatiotemporal and kinetic parameters during easy-paced treadmill running require 11–17 min of continuous data to obtain 1 min epoch estimates that are practically stable relative to 30 min averages, regardless of footwear familiarity. Full article