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19 pages, 2280 KiB  
Article
A Swap-Integrated Procurement Model for Supply Chains: Coordinating with Long-Term Wholesale Contracts
by Min-Yeong Ryu and Pyung-Hoi Koo
Mathematics 2025, 13(15), 2495; https://doi.org/10.3390/math13152495 (registering DOI) - 3 Aug 2025
Abstract
In today’s volatile supply chain environment, organizations require flexible and collaborative procurement strategies. Swap contracts, originally developed as financial instruments, have recently been adopted to address inventory imbalances—such as the 2021 COVID-19 vaccine swap between South Korea and Israel. Despite its increasing adoption [...] Read more.
In today’s volatile supply chain environment, organizations require flexible and collaborative procurement strategies. Swap contracts, originally developed as financial instruments, have recently been adopted to address inventory imbalances—such as the 2021 COVID-19 vaccine swap between South Korea and Israel. Despite its increasing adoption in the real world, theoretical studies on swap-based procurement remain limited. This study proposes an integrated model that combines buyer-to-buyer swap agreements with long-term wholesale contracts under demand uncertainty. The model quantifies the expected swap quantity between parties and embeds it into the profit function to derive optimal order quantities. Numerical experiments are conducted to compare the performance of the proposed strategy with that of a baseline wholesale contract. Sensitivity analyses are performed on key parameters, including demand asymmetry and swap prices. The numerical analysis indicates that the swap-integrated procurement strategy consistently outperforms procurement based on long-term wholesale contracts. Moreover, the results reveal that under the swap-integrated strategy, the optimal order quantity must be adjusted—either increased or decreased—depending on the demand scale of the counterpart and the specified swap price, deviating from the optimal quantity under traditional long-term contracts. These findings highlight the potential of swap-integrated procurement strategies as practical coordination mechanisms across both private and public sectors, offering strategic value in contexts such as vaccine distribution, fresh produce, and other critical products. Full article
(This article belongs to the Special Issue Theoretical and Applied Mathematics in Supply Chain Management)
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37 pages, 9057 KiB  
Review
Palaeoclimatic Geoheritage in the Age of Climate Change: Educational Use of the Pleistocene Glacial and Periglacial Geodiversity
by Paweł Wolniewicz and Maria Górska-Zabielska
Geosciences 2025, 15(8), 294; https://doi.org/10.3390/geosciences15080294 (registering DOI) - 2 Aug 2025
Abstract
The lithological record of past climates and climate changes reveals significant potential in enhancing education and understanding of global climate changes and their impacts on contemporary societies. A relatively young geological record of Pleistocene cooling and glaciations serves as one of the most [...] Read more.
The lithological record of past climates and climate changes reveals significant potential in enhancing education and understanding of global climate changes and their impacts on contemporary societies. A relatively young geological record of Pleistocene cooling and glaciations serves as one of the most useful geo-educational tools. The present study encompasses a comprehensive review of ongoing efforts to assess and communicate the glacial geoheritage of the Pleistocene, with a detailed case study of Poland. A literature review is conducted to evaluate the extent of scientific work on inventorying and communicating the geodiversity of Pleistocene glacial and periglacial environments globally. The study demonstrates a steady increase in the number of scientific contributions focused on the evaluation and promotion of Pleistocene geoheritage, with a notable transition from the description of geosites to the establishment of geoconservation practices and educational strategies. The relative complexity of the palaeoclimatic record and the presence of glacial geodiversity features across extensive areas indicate that effective scientific communication of climate changes requires careful selection of a limited number of geodiversity elements and sediment types. In this context, the use of glacial erratic boulders and rock gardens for promotion of Pleistocene glacial geoheritage is advocated, and the significance of educational initiatives for local communities and the preservation of geocultural heritage is outlined in detail. Full article
(This article belongs to the Special Issue Challenges and Research Trends of Geoheritage and Geoconservation)
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16 pages, 3217 KiB  
Article
Application of an Orbital Remote Sensing Vegetation Index for Urban Tree Cover Mapping to Support the Tree Census
by Cássio Filipe Vieira Martins, Franciele Caroline Guerra, Anderson Targino da Silva Ferreira and Roger Dias Gonçalves
Earth 2025, 6(3), 87; https://doi.org/10.3390/earth6030087 (registering DOI) - 1 Aug 2025
Abstract
Urban vegetation monitoring is essential for sustainable city planning but is often constrained by the high cost and limited frequency of field-based inventories. This study evaluates the use of the Normalized Difference Vegetation Index (NDVI), derived from Sino-Brazilian CBERS-4A satellite imagery, as a [...] Read more.
Urban vegetation monitoring is essential for sustainable city planning but is often constrained by the high cost and limited frequency of field-based inventories. This study evaluates the use of the Normalized Difference Vegetation Index (NDVI), derived from Sino-Brazilian CBERS-4A satellite imagery, as a spatially explicit and low-cost proxy for urban tree census data. CBERS-4A provides medium-resolution multispectral data freely accessible across South America, yet remains underutilized in urban environmental applications. Focusing on Aracaju, a metropolitan region in northeastern Brazil, we compared NDVI-based classification results with official municipal tree census data from 2022. The analysis revealed a strong spatial correlation, supporting the use of NDVI as a reliable indicator of canopy presence at the urban block scale. In addition to mapping vegetation distribution, the NDVI results identified areas with insufficient canopy coverage, directly informing urban greening priorities. By validating remote sensing data against field inventories, this study demonstrates how CBERS-4A imagery and vegetation indices can support municipal tree management and serve as scalable tools for environmental planning and policy. Full article
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34 pages, 3521 KiB  
Review
Overview of Water-Ice in Asteroids—Targets of a Revolution by LSST and JWST
by Ákos Kereszturi, Mohamed Ramy El-Maarry, Anny-Chantal Levasseur-Regourd, Imre Tóth, Bernadett D. Pál and Csaba Kiss
Universe 2025, 11(8), 253; https://doi.org/10.3390/universe11080253 - 30 Jul 2025
Viewed by 117
Abstract
Water-ice occurs inside many minor bodies almost throughout the Solar System. To have an overview of the inventory of water-ice in asteroids, beside the general characteristics of their activity, examples are presented with details, including the Hilda zone and among the Trojans. There [...] Read more.
Water-ice occurs inside many minor bodies almost throughout the Solar System. To have an overview of the inventory of water-ice in asteroids, beside the general characteristics of their activity, examples are presented with details, including the Hilda zone and among the Trojans. There might be several extinct comets among the asteroids with only internal ice content, demonstrating the complex evolution of such bodies. To evaluate the formation of ice-hosting small objects, their migration and retention capacity by a surface covering dust layer are also overviewed to provide a complex picture of volatile occurrences. This review aims to support further work and search for sublimation-induced activity of asteroids by future missions and telescopic surveys. Based on the observed and hypothesized occurrence and characteristics of icy asteroids, future observation-related estimations were made regarding the low limiting magnitude future survey of LSST/Vera Rubin and also the infrared ice identification by the James Webb space telescope. According to these estimations, there is a high probability of mapping the distribution of ice in the asteroid belt over the next decade. Full article
(This article belongs to the Special Issue The Hidden Stories of Small Planetary Bodies)
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17 pages, 924 KiB  
Article
Prolonged Overtime Predicts Worsening Burnout Among Healthcare Workers: A 4-Year Longitudinal Study in Taiwan
by Yong-Hsin Chen, Gwo-Ping Jong, Ching-Wen Yang and Chiu-Hsiang Lee
Healthcare 2025, 13(15), 1859; https://doi.org/10.3390/healthcare13151859 - 30 Jul 2025
Viewed by 288
Abstract
Background: Overtime adversely affects physical and mental health, contributing to irritability, anxiety, reduced sleep, and even cardiovascular issues, ultimately lowering care quality and increasing turnover intentions. This study aimed to investigate whether prolonged overtime increases the risk of occupational burnout over time among [...] Read more.
Background: Overtime adversely affects physical and mental health, contributing to irritability, anxiety, reduced sleep, and even cardiovascular issues, ultimately lowering care quality and increasing turnover intentions. This study aimed to investigate whether prolonged overtime increases the risk of occupational burnout over time among healthcare workers. Methods: We conducted a four-year longitudinal observational study using secondary data from annual surveys (2021–2024) of healthcare workers at a medical university hospital in Taichung, Taiwan. Burnout was assessed using the personal burnout (PB) scale from the Copenhagen Burnout Inventory (CBI), with high PB levels (HPBL) defined as scores in the upper quartile of the 2021 baseline. Survival analysis utilizing the Kaplan–Meier method and Cox regression investigated burnout progression and the effects of overtime. Results: HPBL was defined as PB scores ≥45.83 (upper quartile in 2021). The proportions of HPBL were 30.28% (2021), 33.29% (2022), 36.75% (2023), and 32.51% (2024). Survival analysis confirmed that the risk of burnout increased over time, with the survival time estimated at 2.50 ± 0.03 years and lower survival probabilities observed among participants working overtime (Log-rank test, p < 0.0001). Multivariate logistics revealed overtime work, female gender, being a physician/nurse, and reduced sleep as independent risk factors for HPBL (OR = 3.14 for overtime, p < 0.001). These findings support the hypotheses on burnout progression and the impact of overtime. Conclusions: Overtime significantly heightens the risk of burnout, which worsens over time. Female sex, healthcare roles, obesity, and insufficient sleep are additional risk factors. Limiting overtime and proactive interventions are crucial to preventing burnout in healthcare workers. Full article
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25 pages, 1103 KiB  
Article
The Low-Carbon Development Strategy of Russia Until 2050 and the Role of Forests in Its Implementation
by Evgeny A. Shvarts, Andrey V. Ptichnikov, Anna A. Romanovskaya, Vladimir N. Korotkov and Anastasia S. Baybar
Sustainability 2025, 17(15), 6917; https://doi.org/10.3390/su17156917 - 30 Jul 2025
Viewed by 164
Abstract
This article examines the role of managed ecosystems, and particularly forests, in achieving carbon neutrality in Russia. The range of estimates of Russia’s forests’ net carbon balance in different studies varies by up to 7 times. The. A comparison of Russia’s National GHG [...] Read more.
This article examines the role of managed ecosystems, and particularly forests, in achieving carbon neutrality in Russia. The range of estimates of Russia’s forests’ net carbon balance in different studies varies by up to 7 times. The. A comparison of Russia’s National GHG inventory data for 2023 and 2024 (with the latter showing 37% higher forest sequestration) is presented and explained. The possible changes in the Long-Term Low-Emission Development Strategy of Russia (LT LEDS) carbon neutrality scenario due to new land use, land use change and forestry (LULUCF) data in National GHG Inventory Document (NID) 2024 are discussed. It is demonstrated that the refined net carbon balance should not impact the mitigation ambition in the Russian forestry sector. An assessment of changes in the drafts of the Operational plan of the LT LEDS is presented and it is concluded that its structure and content have significantly improved; however, a delay in operationalization nullifies efforts. The article highlights the problem of GHG emissions increases in forest fires and compares the gap between official “ground-based” and Remote Sensing approaches in calculations of such emissions. Considering the intention to increase net absorption by implementing forest carbon projects, the latest changes in the regulations of such projects are discussed. The limitations of reforestation carbon projects in Russia are provided. Proposals are presented for the development of the national forest policy towards increasing the net forest carbon absorption, including considering the projected decrease in annual net absorption by Russian forests by 2050. The role of government and private investment in improving the forest management of structural measures to adapt forestry to modern climate change and the place of forest climate projects need to be clearly defined in the LT LEDS. Full article
(This article belongs to the Section Sustainable Forestry)
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16 pages, 4347 KiB  
Technical Note
Combining TanDEM-X Interferometry and GEDI Space LiDAR for Estimation of Forest Biomass Change in Tanzania
by Svein Solberg, Belachew Gizachew, Laura Innice Duncanson and Paromita Basak
Remote Sens. 2025, 17(15), 2623; https://doi.org/10.3390/rs17152623 - 28 Jul 2025
Viewed by 454
Abstract
The background for this study is the limitations of the conventional approach of using deforestation area multiplied by biomass densities or emission factors. We demonstrated how TanDEM-X and GEDI data can be combined to estimate forest Above Ground Biomass (AGB) change at the [...] Read more.
The background for this study is the limitations of the conventional approach of using deforestation area multiplied by biomass densities or emission factors. We demonstrated how TanDEM-X and GEDI data can be combined to estimate forest Above Ground Biomass (AGB) change at the national scale for Tanzania. The results can be further recalculated to estimate CO2 emissions and removals from the forest. We used repeated short wavelength, InSAR DEMs from TanDEM-X to derive changes in forest canopy height and combined this with GEDI data to convert such height changes to AGB changes. We estimated AGB change during 2012–2019 to be −2.96 ± 2.44 MT per year. This result cannot be validated, because the true value is unknown. However, we corroborated the results by comparing with other approaches, other datasets, and the results of other studies. In conclusion, TanDEM-X and GEDI can be combined to derive reliable temporal change in AGB at large scales such as a country. An important advantage of the method is that it is not required to have a representative field inventory plot network nor a full coverage DTM. A limitation for applying this method now is the lack of frequent and systematic InSAR elevation data. Full article
(This article belongs to the Section Biogeosciences Remote Sensing)
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22 pages, 2003 KiB  
Article
Assessment of Different Methods to Determine NH3 Emissions from Small Field Plots After Fertilization
by Hannah Götze, Julian Brokötter, Jonas Frößl, Alexander Kelsch, Sina Kukowski and Andreas Siegfried Pacholski
Environments 2025, 12(8), 255; https://doi.org/10.3390/environments12080255 - 28 Jul 2025
Viewed by 280
Abstract
Ammonia (NH3) emissions affect the environment, climate and human health and originate mainly from agricultural sources like synthetic nitrogen fertilizers. Accurate and replicable measurements of NH3 emissions are crucial for research, inventories and evaluation of mitigation measures. There exist specific [...] Read more.
Ammonia (NH3) emissions affect the environment, climate and human health and originate mainly from agricultural sources like synthetic nitrogen fertilizers. Accurate and replicable measurements of NH3 emissions are crucial for research, inventories and evaluation of mitigation measures. There exist specific application limitations of NH3 emission measurement techniques and a high variability in method performance between studies, in particular from small plots. Therefore, the aim of this study was the assessment of measurement methods for ammonia emissions from replicated small plots. Methods were evaluated in 18 trials on six sites in Germany (2021–2022). Urea was applied to winter wheat as an emission source. Two small-plot methods were employed: inverse dispersion modelling (IDM) with atmospheric concentrations obtained from Alpha samplers and the dynamic chamber Dräger tube method (DTM). Cumulative NH3 losses assessed by each method were compared to the results of the integrated horizontal flux (IHF) method using Alpha samplers (Alpha IHF) as a micrometeorological reference method applied in parallel large-plot trials. For validation, Alpha IHF was also compared to IHF/ZINST with Leuning passive samplers. Cumulative NH3 emissions assessed using Alpha IHF and DTM showed good agreement, with a relative root mean square error (rRMSE) of 11%. Cumulative emissions assessed by Leuning IHF/ZINST deviated from Alpha IHF, with an rRMSE of 21%. For low-wind-speed and high-temperature conditions, NH3 losses detected with Alpha IDM had to be corrected to give acceptable agreement (rRMSE 20%, MBE +2 kg N ha−1). The study shows that quantification of NH3 emissions from small plots is feasible. Since DTM is constrained to specific conditions, we recommend Alpha IDM, but the approach needs further development. Full article
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16 pages, 2677 KiB  
Article
The Initial Impact of a Hydroelectric Reservoir on the Floristics, Structure, and Dynamics of Adjacent Forests in the Southern Amazon
by Jesulino Alves da Rocha-Filho, Marco Antônio Camillo de Carvalho, Fabiana Ferreira Cabral Gomes, José Hypolito Piva, Beatriz Schwantes Marimon, Oscar Mitsuo Yamashita and Ben Hur Marimon-Junior
Forests 2025, 16(8), 1236; https://doi.org/10.3390/f16081236 - 27 Jul 2025
Viewed by 159
Abstract
This study assesses whether the rise in water level—following three years of reservoir filling at the Teles Pires Hydroelectric Plant (135.6 km2 water surface) in Southern Amazonia—has affected the floristic composition, structure, and dynamics of adjacent forests. We established 62 permanent plots [...] Read more.
This study assesses whether the rise in water level—following three years of reservoir filling at the Teles Pires Hydroelectric Plant (135.6 km2 water surface) in Southern Amazonia—has affected the floristic composition, structure, and dynamics of adjacent forests. We established 62 permanent plots (2000 m2 each) across a topographic gradient from the reservoir margin and conducted annual tree inventories for individuals with DBH ≥ 10 cm from 2014 to 2017. A total of 6322 individuals were recorded, representing 322 species, 210 genera, and 61 families. Fabaceae was the most abundant family, and the ten species with the highest importance value index (IVI) before reservoir filling remained dominant afterward. The forests exhibited high species richness and were characterized by a few common and many rare species. Mortality rates were highest within 10 m of elevation from the maximum reservoir level, indicating possible hydrological impacts, although no abnormal dieback or sharp shifts in floristic structure were observed. These results suggest limited short-term effects on species composition, but subtle changes in vegetation dynamics underscore the importance of long-term monitoring. Full article
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18 pages, 539 KiB  
Article
Identifying Opponent’s Neuroticism Based on Behavior in Wargame
by Sihui Ge, Sihua Lyu, Yazheng Di, Yue Su, Qian Luo, Aizhu Mei and Tingshao Zhu
Behav. Sci. 2025, 15(8), 1012; https://doi.org/10.3390/bs15081012 - 25 Jul 2025
Viewed by 221
Abstract
Traditional neuroticism assessments primarily rely on self-report questionnaires, which can be difficult to implement in highly confrontational scenarios and are susceptible to subjective biases. To overcome these limitations, this study develops a machine learning-based approach using behavioral data to predict an opponent’s neuroticism [...] Read more.
Traditional neuroticism assessments primarily rely on self-report questionnaires, which can be difficult to implement in highly confrontational scenarios and are susceptible to subjective biases. To overcome these limitations, this study develops a machine learning-based approach using behavioral data to predict an opponent’s neuroticism in competitive environments. We analyzed behavioral records from 167 participants on the MiaoSuan Wargame platform. After data cleaning and feature selection, key behavioral features associated with neuroticism were identified, and predictive models were developed. Neuroticism was assessed using the 8-item neuroticism subscale of the Big Five Inventory. Results indicate that this method can effectively infer an individual’s neuroticism level. The best-performing model was LinearSVR, which balances interpretability, robustness to noise, and the ability to capture moderate nonlinear relationships—making it suitable for behavior-based psychological inference tasks. The correlation between predicted scores and self-reported questionnaire scores was 0.606, the R-squared value was 0.354, and the test–retest reliability was 0.516. These behavioral features provide valuable insights into neuroticism prediction and have practical applications in psychological assessment, particularly in competitive environments where conventional methods are impractical. This study demonstrates the feasibility of behavior-based neuroticism assessment and suggests future research directions, including refining feature selection techniques and expanding the application scenarios. Full article
(This article belongs to the Section Social Psychology)
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16 pages, 4736 KiB  
Review
Volcanic Islands as Reservoirs of Geoheritage: Current and Potential Initiatives of Geoconservation
by Esther Martín-González, Juana Vegas, Inés Galindo, Carmen Romero and Nieves Sánchez
J. Mar. Sci. Eng. 2025, 13(8), 1420; https://doi.org/10.3390/jmse13081420 - 25 Jul 2025
Viewed by 229
Abstract
Volcanic islands host exceptional geological features that illustrate complex endogenic processes and interactions with climatic and marine forces, while also being particularly vulnerable to the impacts of climate change. Despite their scientific, educational, touristic, and aesthetic values, such islands remain underrepresented within the [...] Read more.
Volcanic islands host exceptional geological features that illustrate complex endogenic processes and interactions with climatic and marine forces, while also being particularly vulnerable to the impacts of climate change. Despite their scientific, educational, touristic, and aesthetic values, such islands remain underrepresented within the UNESCO Global Geoparks (UGGp). This study reviews current volcanic island geoparks and evaluates territories with potential for future designation, based on documented geoheritage, geosite inventories, and geoconservation frameworks. Geoparks are categorized according to their dominant narratives—ranging from recent Quaternary volcanism to broader tectonic, sedimentary, and metamorphic histories. Through an analysis of their distribution, management strategies, and integration into territorial planning, this work highlights the challenges that insular territories face, including vulnerability to global environmental change, limited legal protection, and structural inequalities in access to international resources recognition. It concludes that volcanic island geoparks represent strategic platforms for implementing sustainable development models, especially in ecologically and socially fragile contexts. Enhancing their global representation will require targeted efforts in ecologically and socially fragile contexts. Enhancing their global representation will require targeted efforts in capacity building, funding access, and regional cooperation—particularly across the Global South. Full article
(This article belongs to the Special Issue Feature Review Papers in Geological Oceanography)
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21 pages, 597 KiB  
Article
Competency Learning by Machine Learning-Based Data Analysis with Electroencephalography Signals
by Javier M. Antelis, Myriam Alanis-Espinosa, Omar Mendoza-Montoya, Pedro Cervantes-Lozano and Luis G. Hernandez-Rojas
Educ. Sci. 2025, 15(8), 957; https://doi.org/10.3390/educsci15080957 - 25 Jul 2025
Viewed by 265
Abstract
Data analysis and machine learning have become essential cross-disciplinary skills for engineering students and professionals. Traditionally, these topics are taught through lectures or online courses using pre-existing datasets, which limits the opportunity to engage with the full cycle of data analysis and machine [...] Read more.
Data analysis and machine learning have become essential cross-disciplinary skills for engineering students and professionals. Traditionally, these topics are taught through lectures or online courses using pre-existing datasets, which limits the opportunity to engage with the full cycle of data analysis and machine learning, including data collection, preparation, and contextualization of the application field. To address this, we designed and implemented a learning activity that involves students in every step of the learning process. This activity includes multiple stages where students conduct experiments to record their own electroencephalographic (EEG) signals and use these signals to learn data analysis and machine learning techniques. The purpose is to actively involve students, making them active participants in their learning process. This activity was implemented in six courses across four engineering careers during the 2023 and 2024 academic years. To validate its effectiveness, we measured improvements in grades and self-reported motivation using the MUSIC model inventory. The results indicate a positive development of competencies and high levels of motivation and appreciation among students for the concepts of data analysis and machine learning. Full article
(This article belongs to the Section Higher Education)
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31 pages, 2271 KiB  
Article
Research on the Design of a Priority-Based Multi-Stage Emergency Material Scheduling System for Drone Coordination
by Shuoshuo Gong, Gang Chen and Zhiwei Yang
Drones 2025, 9(8), 524; https://doi.org/10.3390/drones9080524 - 25 Jul 2025
Viewed by 298
Abstract
Emergency material scheduling (EMS) is a core component of post-disaster emergency response, with its efficiency directly impacting rescue effectiveness and the satisfaction of affected populations. However, due to severe road damage, limited availability of resources, and logistical challenges after disasters, current EMS practices [...] Read more.
Emergency material scheduling (EMS) is a core component of post-disaster emergency response, with its efficiency directly impacting rescue effectiveness and the satisfaction of affected populations. However, due to severe road damage, limited availability of resources, and logistical challenges after disasters, current EMS practices often suffer from uneven resource distribution. To address these issues, this paper proposes a priority-based, multi-stage EMS approach with drone coordination. First, we construct a three-level EMS network “storage warehouses–transit centers–disaster areas” by integrating the advantages of large-scale transportation via trains and the flexible delivery capabilities of drones. Second, considering multiple constraints, such as the priority level of disaster areas, drone flight range, transport capacity, and inventory capacities at each node, we formulate a bilevel mixed-integer nonlinear programming model. Third, given the NP-hard nature of the problem, we design a hybrid algorithm—the Tabu Genetic Algorithm combined with Branch and Bound (TGA-BB), which integrates the global search capability of genetic algorithms, the precise solution mechanism of branch and bound, and the local search avoidance features of Tabu search. A stage-adjustment operator is also introduced to better adapt the algorithm to multi-stage scheduling requirements. Finally, we designed eight instances of varying scales to systematically evaluate the performance of the stage-adjustment operator and the Tabu search mechanism within TGA-BB. Comparative experiments were conducted against several traditional heuristic algorithms. The experimental results show that TGA-BB outperformed the other algorithms across all eight test cases, in terms of both average response time and average runtime. Specifically, in Instance 7, TGA-BB reduced the average response time by approximately 52.37% compared to TGA-Particle Swarm Optimization (TGA-PSO), and in Instance 2, it shortened the average runtime by about 97.95% compared to TGA-Simulated Annealing (TGA-SA).These results fully validate the superior solution accuracy and computational efficiency of TGA-BB in drone-coordinated, multi-stage EMS. Full article
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18 pages, 3178 KiB  
Article
Biomass Estimation of Apple and Citrus Trees Using Terrestrial Laser Scanning and Drone-Mounted RGB Sensor
by Min-Ki Lee, Yong-Ju Lee, Dong-Yong Lee, Jee-Su Park and Chang-Bae Lee
Remote Sens. 2025, 17(15), 2554; https://doi.org/10.3390/rs17152554 - 23 Jul 2025
Viewed by 283
Abstract
Developing accurate activity data on tree biomass using remote sensing tools such as LiDAR and drone-mounted sensors is essential for improving carbon accounting in the agricultural sector. However, direct biomass measurements of perennial fruit trees remain limited, especially for validating remote sensing estimates. [...] Read more.
Developing accurate activity data on tree biomass using remote sensing tools such as LiDAR and drone-mounted sensors is essential for improving carbon accounting in the agricultural sector. However, direct biomass measurements of perennial fruit trees remain limited, especially for validating remote sensing estimates. This study evaluates the potential of terrestrial laser scanning (TLS) and drone-mounted RGB sensors (Drone_RGB) for estimating biomass in two major perennial crops in South Korea: apple (‘Fuji’/M.9) and citrus (‘Miyagawa-wase’). Trees of different ages were destructively sampled for biomass measurement, while volume, height, and crown area data were collected via TLS and Drone_RGB. Regression analyses were performed, and the model accuracy was assessed using R2, RMSE, and bias. The TLS-derived volume showed strong predictive power for biomass (R2 = 0.704 for apple, 0.865 for citrus), while the crown area obtained using both sensors showed poor fit (R2 ≤ 0.7). Aboveground biomass was reasonably estimated (R2 = 0.725–0.865), but belowground biomass showed very low predictability (R2 < 0.02). Although limited in scale, this study provides empirical evidence to support the development of remote sensing-based biomass estimation methods and may contribute to improving national greenhouse gas inventories by refining emission/removal factors for perennial fruit crops. Full article
(This article belongs to the Special Issue Biomass Remote Sensing in Forest Landscapes II)
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22 pages, 9071 KiB  
Article
Integrating UAV-Based RGB Imagery with Semi-Supervised Learning for Tree Species Identification in Heterogeneous Forests
by Bingru Hou, Chenfeng Lin, Mengyuan Chen, Mostafa M. Gouda, Yunpeng Zhao, Yuefeng Chen, Fei Liu and Xuping Feng
Remote Sens. 2025, 17(15), 2541; https://doi.org/10.3390/rs17152541 - 22 Jul 2025
Viewed by 298
Abstract
The integration of unmanned aerial vehicle (UAV) remote sensing and deep learning has emerged as a highly effective strategy for inventorying forest resources. However, the spatiotemporal variability of forest environments and the scarcity of annotated data hinder the performance of conventional supervised deep-learning [...] Read more.
The integration of unmanned aerial vehicle (UAV) remote sensing and deep learning has emerged as a highly effective strategy for inventorying forest resources. However, the spatiotemporal variability of forest environments and the scarcity of annotated data hinder the performance of conventional supervised deep-learning models. To overcome these challenges, this study has developed efficient tree (ET), a semi-supervised tree detector designed for forest scenes. ET employed an enhanced YOLO model (YOLO-Tree) as a base detector and incorporated a teacher–student semi-supervised learning (SSL) framework based on pseudo-labeling, effectively leveraging abundant unlabeled data to bolster model robustness. The results revealed that SSL significantly improved outcomes in scenarios with sparse labeled data, specifically when the annotation proportion was below 50%. Additionally, employing overlapping cropping as a data augmentation strategy mitigated instability during semi-supervised training under conditions of limited sample size. Notably, introducing unlabeled data from external sites enhances the accuracy and cross-site generalization of models trained on diverse datasets, achieving impressive results with F1, mAP50, and mAP50-95 scores of 0.979, 0.992, and 0.871, respectively. In conclusion, this study highlights the potential of combining UAV-based RGB imagery with SSL to advance tree species identification in heterogeneous forests. Full article
(This article belongs to the Special Issue Remote Sensing-Assisted Forest Inventory Planning)
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