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23 pages, 2032 KiB  
Article
Factors Influencing Nighttime Tourists’ Satisfaction of Urban Lakes: A Case Study of the Daming Lake Scenic Area, China
by Huying Zhu and Mengru Li
Sustainability 2025, 17(14), 6596; https://doi.org/10.3390/su17146596 (registering DOI) - 19 Jul 2025
Abstract
Tourist satisfaction of nighttime urban lakes as scenic areas, such as the Daming Lake, is influenced by multiple factors, which are crucial for tourists’ experiences and the sustainable development of these areas. This paper explores the factors impacting nighttime visitor satisfaction at the [...] Read more.
Tourist satisfaction of nighttime urban lakes as scenic areas, such as the Daming Lake, is influenced by multiple factors, which are crucial for tourists’ experiences and the sustainable development of these areas. This paper explores the factors impacting nighttime visitor satisfaction at the Daming Lake Scenic Area. Basing our studies on analysis of the literature and questionnaire surveys, the study constructs a visitor satisfaction evaluation index system based on the Expectancy-Disconfirmation Theory. Utilizing the revised importance-performance analysis method, the study identifies several significant influencing factors including the distinctive features of nighttime shopping products, the rich variety of nighttime tourscape and entertainment products, the aesthetically pleasing design of nighttime lighting products, the affordable price of nighttime dining products, and the diverse methods, reasonable pricing, and multimodal transit options of nighttime transportation. Furthermore, it finds the main factors that reduce tourists’ satisfaction in nighttime urban lakes include: premium pricing of nighttime shopping and dining products, transport infrastructure deficiencies, the cultural connotation of tourism products, and the safety of nighttime tourscape and entertainment products. This research provides insights to enhance satisfaction in urban lake scenic areas and expands the application of the tourist satisfaction theory. Full article
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37 pages, 2819 KiB  
Article
Macroscopic-Level Collaborative Optimization Framework for IADS: Multiple-Route Terminal Maneuvering Area Scheduling Problem
by Chaoyu Xia, Minghua Hu, Xiuying Zhu, Yi Wen, Junqing Wu and Changbo Hou
Aerospace 2025, 12(7), 639; https://doi.org/10.3390/aerospace12070639 - 18 Jul 2025
Abstract
The terminal maneuvering area (TMA) serves as a critical transition zone between upper enroute airways and airports, representing one of the most complex regions for managing high volumes of arrival and departure traffic. This paper presents the multi-route TMA scheduling problem as an [...] Read more.
The terminal maneuvering area (TMA) serves as a critical transition zone between upper enroute airways and airports, representing one of the most complex regions for managing high volumes of arrival and departure traffic. This paper presents the multi-route TMA scheduling problem as an optimization challenge aimed at optimizing TMA interventions, such as rerouting, speed control, time-based metering, dynamic minimum time separation, and holding procedures; the objective function minimizes schedule deviations and the accumulated holding time. Furthermore, the problem is formulated as a mixed-integer linear program (MILP) to facilitate finding solutions. A rolling horizon control (RHC) dynamic optimization framework is also introduced to decompose the large-scale problem into manageable subproblems for iterative resolution. To demonstrate the applicability and effectiveness of the proposed scheduling models, a hub airport—Chengdu Tianfu International Airport (ICAO code: ZUTF) in the Cheng-Yu Metroplex—is selected for validation. Numerical analyses confirm the superiority of the proposed models, which are expected to reduce aircraft delays, shorten airborne and holding times, and improve airspace resource utilization. This study provides intelligent decision support and engineering design ideas for the macroscopic-level collaborative optimization framework of the Integrated Arrival–Departure and Surface (IADS) system. Full article
(This article belongs to the Collection Air Transportation—Operations and Management)
16 pages, 995 KiB  
Article
An Upper Partial Moment Framework for Pathfinding Problem Under Travel Time Uncertainty
by Xu Zhang and Mei Chen
Systems 2025, 13(7), 600; https://doi.org/10.3390/systems13070600 - 17 Jul 2025
Viewed by 52
Abstract
Route planning under uncertain traffic conditions requires accounting for not only expected travel times but also the risk of late arrivals. This study proposes a mean-upper partial moment (MUPM) framework for pathfinding that explicitly considers travel time unreliability. The framework incorporates a benchmark [...] Read more.
Route planning under uncertain traffic conditions requires accounting for not only expected travel times but also the risk of late arrivals. This study proposes a mean-upper partial moment (MUPM) framework for pathfinding that explicitly considers travel time unreliability. The framework incorporates a benchmark travel time to measure the upper partial moment (UPM), capturing both the probability and severity of delays. By adjusting a risk parameter (θ), the model reflects different traveler risk preferences and unifies several existing reliability measures, including on-time arrival probability, late arrival penalty, and semi-variance. A bi-objective model is formulated to simultaneously minimize mean travel time and UPM. Theoretical analysis shows that the MUPM framework is consistent with the expected utility theory (EUT) and stochastic dominance theory (SDT), providing a behavioral foundation for the model. To efficiently solve the model, an SDT-based label-correcting algorithm is adapted, with a pre-screening step to reduce unnecessary pairwise path comparisons. Numerical experiments using GPS probe vehicle data from Louisville, Kentucky, USA, demonstrate that varying θ values lead to different non-dominated paths. Lower θ values emphasize frequent small delays but may overlook excessive delays, while higher θ values effectively capture the tail risk, aligning with the behavior of risk-averse travelers. The MUPM framework provides a flexible, behaviorally grounded, and computationally scalable approach to pathfinding under uncertainty. It holds strong potential for applications in traveler information systems, transportation planning, and network resilience analysis. Full article
(This article belongs to the Special Issue Data-Driven Urban Mobility Modeling)
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27 pages, 408 KiB  
Article
Quadratic BSDEs with Singular Generators and Unbounded Terminal Conditions: Theory and Applications
by Wenbo Wang and Guangyan Jia
Mathematics 2025, 13(14), 2292; https://doi.org/10.3390/math13142292 - 17 Jul 2025
Viewed by 47
Abstract
We investigate a class of quadratic backward stochastic differential equations (BSDEs) with generators that are singular in y. First, we establish the existence of solutions and a comparison theorem, thereby extending the existing results in the literature. Furthermore, we analyze the stability [...] Read more.
We investigate a class of quadratic backward stochastic differential equations (BSDEs) with generators that are singular in y. First, we establish the existence of solutions and a comparison theorem, thereby extending the existing results in the literature. Furthermore, we analyze the stability properties, derive the Feynman–Kac formula, and prove the uniqueness of viscosity solutions for the corresponding singular semi-linear partial differential equations (PDEs). Finally, we demonstrate applications in the context of robust control linked to stochastic differential utility and the certainty equivalent based on g-expectation. In these applications, the quadratic coefficients in the generators, respectively, quantify ambiguity aversion and absolute risk aversion. Full article
15 pages, 1034 KiB  
Article
In Vitro Oral Cavity Permeability Assessment to Enable Simulation of Drug Absorption
by Pankaj Dwivedi, Priyata Kalra, Haiying Zhou, Khondoker Alam, Eleftheria Tsakalozou, Manar Al-Ghabeish, Megan Kelchen and Giovanni M. Pauletti
Pharmaceutics 2025, 17(7), 924; https://doi.org/10.3390/pharmaceutics17070924 - 17 Jul 2025
Viewed by 122
Abstract
Background/Objectives: The oral cavity represents a convenient route of administration for drugs that exhibit significant hepatic first-pass extraction. In this study, the mucosal permeation properties of selected active pharmaceutical ingredients (APIs) incorporated into oral cavity drug products that are approved by the U.S. [...] Read more.
Background/Objectives: The oral cavity represents a convenient route of administration for drugs that exhibit significant hepatic first-pass extraction. In this study, the mucosal permeation properties of selected active pharmaceutical ingredients (APIs) incorporated into oral cavity drug products that are approved by the U.S. Food and Drug Administration were quantified using the human-derived sublingual HO-1-u-1 and buccal EpiOral™ in vitro tissue models. Methods: Epithelial barrier properties were monitored using propranolol and Lucifer Yellow as prototypic transcellular and paracellular markers. APIs were dissolved in artificial saliva, pH 6.7, and transepithelial flux from the apical to the basolateral compartment was quantified using HPLC. Results: Apparent permeability coefficients (Papp) calculated for these APIs in the sublingual HO-1-u-1 tissue model varied from Papp = 2.72 ± 0.06 × 10−5 cm/s for asenapine to Papp = 6.21 ± 2.60 × 10−5 cm/s for naloxone. In contrast, the buccal EpiOral™ tissue model demonstrated greater discrimination power in terms of permeation properties for the same APIs, with values ranging from Papp = 3.31 ± 0.83 × 10−7 cm/s for acyclovir to Papp = 2.56 ± 0.68 × 10−5 cm/s for sufentanil. The tissue-associated dose fraction recovered at the end of the transport experiment was significantly increased in the buccal EpiOral™ tissue model, reaching up to 8.5% for sufentanil. Conclusions: Experimental permeation data collected for selected APIs in FDA-approved oral cavity products will serve as a training set to aid the development of predictive computational models for improving algorithms that describe drug absorption from the oral cavity. Following a robust in vitro–in vivo correlation analysis, it is expected that such innovative in silico modeling strategies will the accelerate development of generic oral cavity products by facilitating the utility of model-integrated evidence to support decision making in generic drug development and regulatory approval. Full article
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22 pages, 791 KiB  
Article
Turkiye’s Carbon Emission Profile: A Global Analysis with the MEREC-PROMETHEE Hybrid Method
by İrem Pelit and İlker İbrahim Avşar
Sustainability 2025, 17(14), 6527; https://doi.org/10.3390/su17146527 - 16 Jul 2025
Viewed by 163
Abstract
This study conducts a comparative evaluation of Turkiye’s carbon emission profile from both sectoral and global perspectives. Utilizing 2022 data from 76 countries, it applies two widely recognized multi-criteria decision-making (MCDM) methods: MEREC, for determining objective weights of criteria, and PROMETHEE II, for [...] Read more.
This study conducts a comparative evaluation of Turkiye’s carbon emission profile from both sectoral and global perspectives. Utilizing 2022 data from 76 countries, it applies two widely recognized multi-criteria decision-making (MCDM) methods: MEREC, for determining objective weights of criteria, and PROMETHEE II, for ranking countries based on these criteria. All data used in the analysis were obtained from the World Bank, a globally recognized and credible statistical source. The study evaluates seven criteria, including carbon emissions from the energy, transport, industry, and residential sectors, along with GDP-related indicators. The results indicate that Turkiye’s carbon emissions, particularly from industry, transport, and energy, are substantially higher than the global average. Moreover, countries with higher levels of industrialization generally rank lower in environmental performance, highlighting a direct relationship between industrial activity and increased carbon emissions. According to PROMETHEE II rankings, Turkiye falls into the lower-middle tier among the assessed countries. In light of these findings, the study suggests that Turkiye should implement targeted, sector-specific policy measures to reduce emissions. The research aims to provide policymakers with a structured, data-driven framework that aligns with the country’s broader sustainable development goals. MEREC was selected for its ability to produce unbiased criterion weights, while PROMETHEE II was chosen for its capacity to deliver clear and meaningful comparative rankings, making both methods highly suitable for evaluating environmental performance. This study also offers a broader analysis of how selected countries compare in terms of their carbon emissions. As carbon emissions remain one of the most pressing environmental challenges in the context of global warming and climate change, ranking countries based on emission levels serves both to support scientific inquiry and to increase international awareness. By relying on recent 2022 data, the study offers a timely snapshot of the global carbon emission landscape. Alongside its contribution to public awareness, the findings are expected to support policymakers in developing effective environmental strategies. Ultimately, this research contributes to the academic literature and lays a foundation for more sustainable environmental policy development. Full article
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28 pages, 8203 KiB  
Article
Sustainable Development of Central and Northern Euboea (Evia) Through the Protection and Revealing of the Area’s Cultural and Environmental Reserve
by Kyriakos Lampropoulos, Anastasia Vythoulka, George Petrakos, Vasiliki (Betty) Charalampopoulou, Anastasia A. Kioussi and Antonia Moropoulou
Land 2025, 14(7), 1467; https://doi.org/10.3390/land14071467 - 15 Jul 2025
Viewed by 235
Abstract
This study explores a strategic framework for the sustainable development of Northern and Central Euboea (Evia), Greece, through the preservation and promotion of cultural and environmental assets. This research aims to redirect tourism flows from overdeveloped coastal zones to underutilized inland areas by [...] Read more.
This study explores a strategic framework for the sustainable development of Northern and Central Euboea (Evia), Greece, through the preservation and promotion of cultural and environmental assets. This research aims to redirect tourism flows from overdeveloped coastal zones to underutilized inland areas by leveraging local heritage and natural resources. The methodology was developed within the context of the AEI research project and combines bibliographic research, stakeholder consultation, GIS analysis, and socioeconomic assessment. Based on this framework, a series of thematic cultural routes and agritourism initiatives were designed to enhance regional attractiveness and resilience. The study proposes the utilization of ICT tools such as GIS-based mapping, a digital development platform, and an online tourism portal to document, manage, and promote key assets. The socioeconomic impact of the proposed interventions was evaluated using an input–output model, revealing that each EUR 1 million invested in the region is expected to generate EUR 650,000 in local GDP and create 14 new jobs. The results underscore the potential of alternative tourism to stimulate inclusive and sustainable growth, particularly in post-disaster rural regions. This integrated approach can serve as a model for other territories facing similar environmental, economic, and demographic challenges. Full article
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12 pages, 5245 KiB  
Article
Evaluation of Fly Ash Composition from Municipal Solid Waste Incinerators: The Role of the Incinerator Type and Flue Gas Deacidification Process
by Xuetong Qu, Yanan Wang, Feifei Chen, Chuqiao Li, Yunfei He, Jibo Dou, Shuai Zhang, Jiafeng Ding, Hangjun Zhang and Yuchi Zhong
Toxics 2025, 13(7), 588; https://doi.org/10.3390/toxics13070588 - 14 Jul 2025
Viewed by 159
Abstract
The resource utilization potential and environmental impact of fly ash from municipal solid waste incinerators (MSWIs) have attracted wide attention. In this study, four MSWIs in Hangzhou, Zhejiang Province were selected to systematically evaluate the effects of different incinerator types and flue gas [...] Read more.
The resource utilization potential and environmental impact of fly ash from municipal solid waste incinerators (MSWIs) have attracted wide attention. In this study, four MSWIs in Hangzhou, Zhejiang Province were selected to systematically evaluate the effects of different incinerator types and flue gas deacidification processes on fly ash’s oxide and heavy metal components and their temporal changes as well as conduct risk assessment. The results showed that the contents of MgO, Al2O3, SiO2, and Fe2O3 in the grate furnace fly ash were significantly lower than those in the fluidized bed fly ash, but the compressive strength of its fly ash was high. Chemicals added during the flue gas deacidification process such as CaO and NaHCO3 significantly affected the contents of CaO and Na2O. In addition, heavy metals such as Cu, Mn, Cr, and Ni were mainly distributed in the fluidized bed fly ash, while heavy metals such as Pb and Cd were mainly collected in the grate furnace fly ash. The concentrations of various components in the fly ash fluctuated but were not significant under different time dimensions. Risk assessment indicated that heavy metals such as Cd, Pb, and Sb posed a high risk. This study is expected to provide theoretical support for the safe management and resource utilization of fly ash. Full article
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12 pages, 2564 KiB  
Article
Genetic Diversity and Population Structure Analysis of Luhua chickens Based on Genome-Wide Markers
by Qianwen Yang, Wei Han, Jun Yan, Chenghao Zhou, Guohui Li, Huiyong Zhang, Jianmei Yin and Xubin Lu
Animals 2025, 15(14), 2071; https://doi.org/10.3390/ani15142071 - 14 Jul 2025
Viewed by 152
Abstract
The Luhua chicken is an outstanding local breed in China that has been placed under conservation due to the impact of specialized breeding and the widespread adoption of commercial varieties. As such, this study analyzed reproductive traits across three consecutive generations and utilized [...] Read more.
The Luhua chicken is an outstanding local breed in China that has been placed under conservation due to the impact of specialized breeding and the widespread adoption of commercial varieties. As such, this study analyzed reproductive traits across three consecutive generations and utilized whole-genome resequencing data from 60 Luhua chickens to assess conservation efficacy through genetic diversity, run of homozygosity (ROH) distribution, kinship, and population structure so as to better conserve the breed. The results show that, across generations, the body weight at first egg increased, the age at first egg was delayed, and the egg weight at first laying increased. No significant variations were found in the body weight at 300 d or the total egg number. The key genetic parameters of the polymorphism information content (PIC), expected heterozygosity (HE), observed heterozygosity (HO), and mean identical-by-state (IBS) distance were 0.234, 0.351, 0.277, and 0.782, respectively. The majority of ROHs ranged from 0.5 to 1 Mb, and the inbreeding coefficient based on ROHs was calculated at 0.021. The findings reveal that these traits remained unchanged across the three generations. Our research suggests that optimizing the mating plan of Luhua chickens is essential to minimize inbreeding risk. Furthermore, the methodology applied in this study provides a valuable reference for the conservation monitoring of other indigenous chicken breeds. Full article
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36 pages, 1973 KiB  
Article
A Comparative Life Cycle Assessment of an Electric and a Conventional Mid-Segment Car: Evaluating the Role of Critical Raw Materials in Potential Abiotic Resource Depletion
by Andrea Cappelli, Nicola Stefano Trimarchi, Simone Marzeddu, Riccardo Paoli and Francesco Romagnoli
Energies 2025, 18(14), 3698; https://doi.org/10.3390/en18143698 - 13 Jul 2025
Viewed by 308
Abstract
Electric passenger vehicles are set to dominate the European car market, driven by EU climate policies and the 2035 ban on internal combustion engine production. This study assesses the sustainability of this transition, focusing on global warming potential and Critical Raw Material (CRM) [...] Read more.
Electric passenger vehicles are set to dominate the European car market, driven by EU climate policies and the 2035 ban on internal combustion engine production. This study assesses the sustainability of this transition, focusing on global warming potential and Critical Raw Material (CRM) extraction throughout its life cycle. The intensive use of CRMs raises environmental, economic, social, and geopolitical concerns. These materials are scarce and are concentrated in a few politically sensitive regions, leaving the EU highly dependent on external suppliers. The extraction, transport, and refining of CRMs and battery production are high-emission processes that contribute to climate change and pose risks to ecosystems and human health. A Life Cycle Assessment (LCA) was conducted, using OpenLCA software and the Ecoinvent 3.10 database, comparing a Peugeot 308 in its diesel and electric versions. This study adopts a cradle-to-grave approach, analyzing three phases: production, utilization, and end-of-life treatment. Key indicators included Global Warming Potential (GWP100) and Abiotic Resource Depletion Potential (ADP) to assess CO2 emissions and mineral resource consumption. Technological advancements could mitigate mineral depletion concerns. Li-ion battery recycling is still underdeveloped, but has high recovery potential, with the sector expected to expand significantly. Moreover, repurposing used Li-ion batteries for stationary energy storage in renewable energy systems can extend their lifespan by over a decade, decreasing the demand for new batteries. Such innovations underscore the potential for a more sustainable electric vehicle industry. Full article
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21 pages, 15482 KiB  
Article
InSAR Detection of Slow Ground Deformation: Taking Advantage of Sentinel-1 Time Series Length in Reducing Error Sources
by Machel Higgins and Shimon Wdowinski
Remote Sens. 2025, 17(14), 2420; https://doi.org/10.3390/rs17142420 - 12 Jul 2025
Viewed by 164
Abstract
Using interferometric synthetic aperture radar (InSAR) to observe slow ground deformation can be challenging due to many sources of error, with tropospheric phase delay and unwrapping errors being the most significant. While analytical methods, weather models, and data exist to mitigate tropospheric error, [...] Read more.
Using interferometric synthetic aperture radar (InSAR) to observe slow ground deformation can be challenging due to many sources of error, with tropospheric phase delay and unwrapping errors being the most significant. While analytical methods, weather models, and data exist to mitigate tropospheric error, most of these techniques are unsuitable for all InSAR applications (e.g., complex tropospheric mixing in the tropics) or are deficient in spatial or temporal resolution. Likewise, there are methods for removing the unwrapping error, but they cannot resolve the true phase when there is a high prevalence (>40%) of unwrapping error in a set of interferograms. Applying tropospheric delay removal techniques is unnecessary for C-band Sentinel-1 InSAR time series studies, and the effect of unwrapping error can be minimized if the full dataset is utilized. We demonstrate that using interferograms with long temporal baselines (800 days to 1600 days) but very short perpendicular baselines (<5 m) (LTSPB) can lower the velocity detection threshold to 2 mm y−1 to 3 mm y−1 for long-term coherent permanent scatterers. The LTSPB interferograms can measure slow deformation rates because the expected differential phases are larger than those of small baselines and potentially exceed the typical noise amplitude while also reducing the sensitivity of the time series estimation to the noise sources. The method takes advantage of the Sentinel-1 mission length (2016 to present), which, for most regions, can yield up to 300 interferograms that meet the LTSPB baseline criteria. We demonstrate that low velocity detection can be achieved by comparing the expected LTSPB differential phase measurements to synthetic tests and tropospheric delay from the Global Navigation Satellite System. We then characterize the slow (~3 mm/y) ground deformation of the Socorro Magma Body, New Mexico, and the Tampa Bay Area using LTSPB InSAR analysis. The method we describe has implications for simplifying the InSAR time series processing chain and enhancing the velocity detection threshold. Full article
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24 pages, 15200 KiB  
Article
The Difference in MODIS Aerosol Retrieval Accuracy over Chinese Forested Regions
by Masroor Ahmed, Yongjing Ma, Lingbin Kong, Yulong Tan and Jinyuan Xin
Remote Sens. 2025, 17(14), 2401; https://doi.org/10.3390/rs17142401 - 11 Jul 2025
Viewed by 156
Abstract
The updated MODIS Collection 6.1 (C6.1) Dark Target (DT) aerosol optical depth (AOD) is extensively utilized in aerosol-climate studies in China. Nevertheless, the long-term accuracy of this data remains under-evaluated, especially for the forested areas. This study was undertaken to substantiate the accuracy [...] Read more.
The updated MODIS Collection 6.1 (C6.1) Dark Target (DT) aerosol optical depth (AOD) is extensively utilized in aerosol-climate studies in China. Nevertheless, the long-term accuracy of this data remains under-evaluated, especially for the forested areas. This study was undertaken to substantiate the accuracy of MODIS Terra (MOD04) and Aqua (MYD04) at 3 km resolution AOD retrievals at six forested sites in China from 2004 to 2022. The results revealed that MODIS C6.1 DT MOD04 and MYD04 datasets display good correlation (R = 0.75), low RMSE (0.20, 0.18), but significant underestimation, with only 53.57% (Terra) and 52.20% (Aqua) of retrievals within expected error (EE). Both the Terra and Aqua struggled in complex terrain (Gongga Mt.) and high aerosol loads (AOD > 1). In northern sites, MOD04 outperformed MYD04 with better correlation and a relatively high number of retrievals percentage within EE. In contrast, MYD04 outperformed MOD04 in central region with better R (0.69 vs. 0.62), and high percentage within EE (68.70% vs. 63.62%). Since both products perform well in the central region, MODIS C6.1 DT products are recommended for this region. In southern sites, MOD04 product performs relatively better than MYD04 with a marginally higher percentage within EE. However, MYD04 shows better correlation, although a higher number of retrievals fall below EE compared to MOD04. Seasonal biases, driven by snow and dust, were pronounced at northern sites during winter and spring. Southern sites faced issues during biomass burning seasons and complex terrain further degraded accuracy. MOD04 demonstrated a marginally superior performance compared to MYD04, yet both failed to achieve the global validation benchmark (66% within). The proposed results highlight critical limitations of current aerosol retrieval algorithms in forest and mountainous landscapes, necessitating methodological refinements to improve satellite-based derived AOD accuracy in ecological sensitive areas. Full article
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16 pages, 3084 KiB  
Article
Generating Large Time–Bandwidth Product RF-Chirped Waveforms Using Vernier Dual-Optical Frequency Combs
by Mohammed S. Alshaykh
Photonics 2025, 12(7), 700; https://doi.org/10.3390/photonics12070700 - 11 Jul 2025
Viewed by 162
Abstract
Chirped radio-frequency signals are essential waveforms in radar systems. To enhance resolution and improve the signal-to-noise ratio through higher energy transmission, chirps with high time–bandwidth products are highly desirable. Photonic technologies, with their ability to handle broad electrical bandwidths, have been widely employed [...] Read more.
Chirped radio-frequency signals are essential waveforms in radar systems. To enhance resolution and improve the signal-to-noise ratio through higher energy transmission, chirps with high time–bandwidth products are highly desirable. Photonic technologies, with their ability to handle broad electrical bandwidths, have been widely employed in the generation, filtering, processing, and detection of broadband electrical waveforms. In this work, we propose a photonics-based large-TBWP RF chirp generator utilizing dual optical frequency combs with a small difference in the repetition rate. By employing dispersion modules for frequency-to-time mapping, we convert the spectral interferometric patterns into a temporal RF sinusoidal carrier signal whose frequency is swept through the optical shot-to-shot delay. We derive analytical expressions to quantify the system’s performance under various design parameters, including the comb repetition rate and its offset, the second-order dispersion, the transform-limited optical pulse width, and the photodetector’s bandwidth limitations. We benchmark the expected system performance in terms of RF bandwidth, chirp duration, chirp rate, frequency step size, and TBWP. Using realistic dual-comb source parameters, we demonstrate the feasibility of generating RF chirps with a duration of 284.44 μs and a bandwidth of 234.05 GHz, corresponding to a TBWP of 3.3×107. Full article
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17 pages, 6277 KiB  
Article
Adapting Newly Constructed Well Depth to Groundwater Level Changes
by Baoqi Li, Yao Lu, Shaoxiong Zhang, Yanyu Chi, Hang Zhou, Ming Liu and Yi Guo
Water 2025, 17(14), 2066; https://doi.org/10.3390/w17142066 - 10 Jul 2025
Viewed by 152
Abstract
Groundwater is a vital resource for human activities, and its level changes influence the depth design and operation of wells. This study analyzed the Hebei Plain using 1127 boreholes to delineate aquifers I–IV via Kriging interpolation. Groundwater and wells were classified. Utilizing over [...] Read more.
Groundwater is a vital resource for human activities, and its level changes influence the depth design and operation of wells. This study analyzed the Hebei Plain using 1127 boreholes to delineate aquifers I–IV via Kriging interpolation. Groundwater and wells were classified. Utilizing over 120,000 wells, this study analyzed depth trends for shallow/deep wells, developed well-depth models, and examined type correlation, while evaluating adjustments in new well depths in response to groundwater level changes. The results reveal shallow groundwater depth decreased by 0.29 m/yr from 2005 to 2019, reaching 73.84 m, and then rebounded 1.22 m/yr during 2019–2021 to 15.27 m; deep groundwater depth declined continuously at 0.78 m/yr over 2005–2021, reaching 105.82 m. Well-depth models show shallow well depths increased over time (peaking at 77.26 m) but project future declines, while deep wells exhibited continuous depth reduction (minimum 180.33 m) with ongoing decrease expected. The sensitivity of newly constructed well depths to groundwater fluctuations had the following order: rural domestic > agricultural > industrial for shallow wells, and agricultural > rural domestic > industrial for deep wells. This study informs future well-depth planning near overexploited zones and supports well optimization, irrigation management, strategy adjustment, and groundwater conservation. Full article
(This article belongs to the Section Hydrogeology)
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22 pages, 29188 KiB  
Article
Sensitive Object Trigger-Based Fragile Watermarking for Integrity Verification of Remote Sensing Object Detection Models
by Xin Xu, Zihao Wang, Weitong Chen, Wei Tang, Na Ren and Changqing Zhu
Remote Sens. 2025, 17(14), 2379; https://doi.org/10.3390/rs17142379 - 10 Jul 2025
Viewed by 164
Abstract
Remote sensing object detection (RSOD) models are widely deployed on edge devices for critical applications. Their security and integrity have become urgent concerns. This work proposes a fragile model watermarking method that enables black-box integrity verification for RSOD models. Specifically, for a given [...] Read more.
Remote sensing object detection (RSOD) models are widely deployed on edge devices for critical applications. Their security and integrity have become urgent concerns. This work proposes a fragile model watermarking method that enables black-box integrity verification for RSOD models. Specifically, for a given RSOD model, we construct class-specific sensitive object triggers and corresponding fragile watermark samples for each target category. During the trigger generation process, a trained surrogate model is first employed to construct the initial sensitive object trigger, where real objects are utilized to guide the trigger to acquire weak semantic features of the target class. This trigger is then jointly optimized using both the original model and a tampered version. The original model ensures that the trigger remains recognizable, while the tampered model encourages sensitivity to parameter changes. During integrity verification, the model is queried with all the fragile watermark samples. The model is considered intact only if all predictions match the expected results. Extensive experiments demonstrate that the proposed method is effective across multiple RSOD models. It exhibits high sensitivity to various model modifications, including backdoor injection, fine-tuning, pruning, random parameter perturbation, and model compression. Full article
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