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Search Results (251)

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19 pages, 485 KiB  
Article
The Green Finance Reform Pilot Zone Policy and Corporate Sustainable Development Performance: A Quasi-Natural Experiment from China
by Shunping Teng and Haslindar Ibrahim
Sustainability 2025, 17(15), 6674; https://doi.org/10.3390/su17156674 - 22 Jul 2025
Viewed by 110
Abstract
This study investigates the effect of the Green Finance Reform Pilot Zone Policy (GFRPZP) on corporate sustainable development performance (SDP) using a multi-period difference-in-differences (DIDs) regression model. This model incorporates control variables, reflecting firm-level characteristics and regional economic conditions. The results show that [...] Read more.
This study investigates the effect of the Green Finance Reform Pilot Zone Policy (GFRPZP) on corporate sustainable development performance (SDP) using a multi-period difference-in-differences (DIDs) regression model. This model incorporates control variables, reflecting firm-level characteristics and regional economic conditions. The results show that GFRPZP significantly enhances corporate SDP, with stronger effects observed among non-state-owned enterprises (Non-SOEs), companies situated in eastern regions, those in non-heavily polluting industries, and high-tech companies. Mediation analysis indicates that the policy enhances sustainable development through four main channels: improving the quality and quantity of green innovation, easing financing constraints, and increasing analyst attention. Moderation analysis further demonstrates that digital transformation and internal control strengthen the policy’s effect. Full article
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12 pages, 1450 KiB  
Article
Polyhydramnios at Term in Gestational Diabetes: Should We Be Concerned?
by Mercedes Horcas-Martín, Tania Luque-Patiño, Claudia Usandizaga-Prat, Elena Díaz-Fernández, Victoria Melero-Jiménez, Luis Vázquez-Fonseca, Francisco Visiedo, José Román Broullón-Molanes, Rocío Quintero-Prado and Fernando Bugatto
Children 2025, 12(7), 920; https://doi.org/10.3390/children12070920 - 11 Jul 2025
Viewed by 326
Abstract
Background/Objectives: Pregnancies complicated by idiopathic polyhydramnios are linked to a heightened risk of numerous maternal and perinatal complications. We aim to study the implications of polyhydramnios in term pregnancies complicated with gestational diabetes mellitus (GDM). Methods: A prospective cohort study including 340 GDM [...] Read more.
Background/Objectives: Pregnancies complicated by idiopathic polyhydramnios are linked to a heightened risk of numerous maternal and perinatal complications. We aim to study the implications of polyhydramnios in term pregnancies complicated with gestational diabetes mellitus (GDM). Methods: A prospective cohort study including 340 GDM cases was conducted. An ultrasound scan was conducted at term between 37 and 40 weeks and amniotic fluid volume (AFV) was assessed by measuring the amniotic fluid index (AFI) and the single deepest pocket (SDP). Maternal demographics and obstetric and perinatal outcomes were evaluated after delivery. We performed comparisons between groups with normal AFV and polyhydramnios (AFI ≥ 24 cm or SDP ≥ 8 cm), and between groups with normal and increased AFV (AFI or SDP ≥ 75th centile). A multivariate logistic regression analysis was performed to study association between AVF measurements and adverse maternal and perinatal outcomes. Results: We found that women with GDM and polyhydramnios at term had a higher risk of maternal (54.3 vs. 27.5%, p < 0.001) and perinatal adverse outcomes (65.7% vs. 46.5%, p < 0.03). The increased AFV group showed a higher risk of fetal overgrowth (LGA: 21.4% vs. 8.2%, p < 0.001 and macrosomia: 19.8% vs. 5.4%, p < 0.001, respectively) and a lesser risk of delivering an SGA fetus (6.3% vs. 13.6%, respectively). Both AFI and SDP showed a significant correlation with newborn weight (r = 0.27; p < 0.001 and r = 0.28; p < 0.001, respectively) and newborn centile (r = 0.26; p < 0.001 and r = 0.26 for both). Subsequent to conducting a multivariate logistic regression analysis adjusted for pregestational BMI, nulliparity, and insulin treatment, both AFI and SDP were significantly associated with perinatal complications, but AFI showed a stronger association with fetal overgrowth (aOR 1.11; p = 0.004 for a LGA fetus and aOR 1.12; p = 0.002 for macrosomia) and with lower risk of delivering an SGA fetus (aOR 0.89; p = 0.009) or IUGR fetus (aOR 0.86; p = 0.03). ROC analysis showed a poor diagnostic performance of both AFI and SDP for identifying macrosomia (AUC 0.68 for AFI, and 0.65 for SDP). Conclusions: Detection of polyhydramnios at term, whether using AFI or SDP, identifies a subgroup of women with gestational diabetes with higher risks of obstetric and perinatal complications. Cases with increased AFV (AFI ≥ 18 cm or SDP ≥ 6.5 cm) are also associated with an increased risk of fetal overgrowth and may require more intensive monitoring for management and optimal delivery timing, with the aim of improve perinatal outcomes. Full article
(This article belongs to the Special Issue Advances in Prenatal Diagnosis and Their Impact on Neonatal Outcomes)
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24 pages, 538 KiB  
Article
Bias-Reduced Localization for Drone Swarm Based on Sensor Selection
by Bo Wu, Bazhong Shen, Yonggan Zhang, Li Yang and Zhiguo Wang
Sensors 2025, 25(13), 4034; https://doi.org/10.3390/s25134034 - 28 Jun 2025
Viewed by 294
Abstract
To address the problem of accurate localization of high-speed drone swarm intrusions, this paper adopts time difference of arrival (TDOA) and frequency difference of arrival (FDOA) measurements, aiming to improve the performance of estimating the motion state of drone swarms. To this end, [...] Read more.
To address the problem of accurate localization of high-speed drone swarm intrusions, this paper adopts time difference of arrival (TDOA) and frequency difference of arrival (FDOA) measurements, aiming to improve the performance of estimating the motion state of drone swarms. To this end, a two-step strategy is proposed in this study. Firstly, a small number of sensor nodes with random locations are selected in the wireless sensor network, and the constraint-weighted least squares (CWLS) method is used to obtain the rough position and speed information of the drone swarm. Based on this rough information, the objective function of node optimization is constructed and solved using the randomized semidefinite program (SDP) algorithm proposed in this paper to screen out the sensor nodes with optimal localization performance. Secondly, the sensor nodes screened in the first step are used to re-localize the drone swarm, and the CWLS problem is constructed by combining the TDOA and FDOA measurements, and a deviation elimination scheme is proposed to further improve the localization accuracy of the drone swarm. Simulation results show that the randomized SDP algorithm proposed in this paper has the optimal localization effect, and moreover, the bias reduction scheme proposed in this paper can make the localization error of the drone swarm reach the Cramér–Rao Lower Bound (CRLB) with a low signal-to-noise ratio (SNR). Full article
(This article belongs to the Section Sensor Networks)
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24 pages, 11676 KiB  
Article
Rotating Machinery Structural Faults Feature Enhancement and Diagnosis Based on Multi-Sensor Information Fusion
by Baozhu Jia, Guanlong Liang, Zhende Huang, Xuewei Song and Zhiqiang Liao
Machines 2025, 13(7), 553; https://doi.org/10.3390/machines13070553 - 25 Jun 2025
Viewed by 220
Abstract
To address the challenges posed by the difficulty of extracting fault features from rotating machinery with weak fault features, this paper proposes a rotating machinery structural faults feature enhancement and diagnosis method based on multi-sensor information fusion. Firstly, Savitzky–Golay filtering suppresses noise and [...] Read more.
To address the challenges posed by the difficulty of extracting fault features from rotating machinery with weak fault features, this paper proposes a rotating machinery structural faults feature enhancement and diagnosis method based on multi-sensor information fusion. Firstly, Savitzky–Golay filtering suppresses noise and enhances fault features. Secondly, the designed multi-sensor symmetric dot pattern (SDP) transformation method fuses multi-source information of the rotating machinery structural faults, providing more comprehensive and richer fault feature information for diagnosis. Finally, the ResNet18 model performs fault diagnosis. To validate the feasibility and effectiveness of the proposed method, two datasets verify its performance. The accuracy of the experimental results was 99.16% and 100%, respectively, demonstrating the feasibility and effectiveness of the proposed method. To further validate the superiority of the proposed method, it was compared with different 2D signal transformation methods. The comparison results indicate that the proposed method achieves the best fault diagnosis accuracy compared to other methods. Full article
(This article belongs to the Section Machines Testing and Maintenance)
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20 pages, 682 KiB  
Article
The Impact of Artificial Intelligence on the Sustainable Development Performance of Chinese Manufacturing Enterprises
by Chaobo Zhou
Systems 2025, 13(7), 496; https://doi.org/10.3390/systems13070496 - 20 Jun 2025
Viewed by 473
Abstract
As a major driving force in the current technological revolution, artificial intelligence (AI) has significantly accelerated the intelligence, automation, and informatization of enterprises, thereby inevitably influencing the sustainable development performance (SDP) of manufacturing enterprises. This study takes the “Next-Generation AI Innovation Pilot Zone” [...] Read more.
As a major driving force in the current technological revolution, artificial intelligence (AI) has significantly accelerated the intelligence, automation, and informatization of enterprises, thereby inevitably influencing the sustainable development performance (SDP) of manufacturing enterprises. This study takes the “Next-Generation AI Innovation Pilot Zone” policy as a case study and utilizes a multi-period difference-in-differences (DID) model and machine learning techniques to investigate the impact of AI on the SDP of Chinese manufacturing enterprises. The findings indicate that AI contributes to improving the SDP of manufacturing firms. The mechanism analysis reveals that AI enhances SDP via a green innovation effect, cost-saving effect, and digital transformation effect. The moderation analysis further shows that the CEO duality inhibits the positive impact of AI on SDP. The heterogeneity results based on the GRF model indicate that the positive relationship between AI and SDP is pronounced in state-owned enterprises and heavily polluting firms. This study not only enriches the literature on the micro-level environmental effects of AI but also provides valuable insights for governments and businesses seeking to improve SDP. Full article
(This article belongs to the Special Issue Information Systems Driving Corporate Sustainability)
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16 pages, 2821 KiB  
Article
UAV-Assisted Localization of Ground Nodes in Urban Environments Using Path Loss Measurements
by Yaser Bakhuraisa, Heng Siong Lim, Yee Kit Chan and Muhammad Hilman
Drones 2025, 9(6), 450; https://doi.org/10.3390/drones9060450 - 19 Jun 2025
Viewed by 329
Abstract
This paper proposes a distance estimation error reduction framework to improve ground node localization accuracy in urban environments using an unmanned aerial vehicle (UAV) and path loss measurements. The primary goal of the framework is to bound distance estimation errors arising from inherent [...] Read more.
This paper proposes a distance estimation error reduction framework to improve ground node localization accuracy in urban environments using an unmanned aerial vehicle (UAV) and path loss measurements. The primary goal of the framework is to bound distance estimation errors arising from inherent inaccuracies in path loss measurements. A k-means clustering algorithm is first applied to identify the region in which the ground node is located. Then, an analytical approach is used to select UAV waypoints. Moreover, a mean-based exponential smoothing approach is employed to refine the path loss measurements of the selected waypoints to mitigate the effects of multipath components that introduce significant errors in distance estimation. Finally, two estimators, maximum likelihood (ML)-based and semidefinite programming (SDP)-based relaxation, are employed to estimate the ground node’s location, validating the effectiveness of the proposed framework. Evaluations using ray tracing simulation data demonstrate a notable improvement in localization accuracy. The proposed framework effectively bounds the distance estimation errors and significantly reduces overall localization errors compared to conventional unbounded methods. Moreover, both estimators with the proposed framework achieve comparable localization accuracy, highlighting the framework’s capability to address key challenges in ML-based localization. Full article
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41 pages, 11437 KiB  
Article
A Decision Support System for Managed Aquifer Recharge Through Non-Conventional Waters in the South of the Mediterranean
by Rym Hadded, Mongi Ben Zaied, Fatma Elkmali, Giulio Castelli, Fethi Abdelli, Zouhaier Khabir, Khaled Ben Zaied, Elena Bresci and Mohamed Ouessar
Resources 2025, 14(4), 63; https://doi.org/10.3390/resources14040063 - 11 Apr 2025
Viewed by 2006
Abstract
Water management in arid regions faces significant challenges due to limited water resources and increasing competition among sectors. Climate change (CC) exacerbates these issues, highlighting the need for advanced modeling tools to predict trends and guide sustainable resource management. This study employs Water [...] Read more.
Water management in arid regions faces significant challenges due to limited water resources and increasing competition among sectors. Climate change (CC) exacerbates these issues, highlighting the need for advanced modeling tools to predict trends and guide sustainable resource management. This study employs Water Evaluation And Planning (WEAP) software to develop a Decision Support System (DSS) to evaluate the impact of climate change and water management strategies on the Triassic aquifer of “Sahel El Ababsa” in southeast Tunisia up to 2050. The reference scenario (SC0) assumes constant climatic and socio-economic conditions as of 2020. CC is modeled under RCP4.5 (SC1.0) and RCP8.5 (SC2.0). Additional scenarios include Seawater Desalination Plants (SDPs) (SC3.0 and SC4.0), water harvesting techniques (SC5.0) to highlight their impact on the recharge, and irrigation management strategies (SC6.0). All these scenarios were further developed under the “SC1.0” scenario to assess the impact of moderate CC. The initial aquifer storage is estimated at 100 Million cubic meters (Mm3). Under (SC0), storage would decrease by 76%, leaving only 23.7 Mm3 by 2050. CC scenarios (SC1.0, SC2.0) predict about a 98% reduction. The implementation of the Zarat SDP (SC3.0) would lead to a 45% improvement compared to reference conditions by the end of the simulation period, while its extension (SC4.0) would result in a 69.5% improvement. Under moderate CC, these improvements would be reduced, with SC3.1 showing a 59% decline and SC4.1 a 35% decline compared to the reference scenario. The WHT scenario (SC5.0) demonstrated a 104% improvement in Triassic aquifer storage by 2050 compared to the reference scenario. However, under CC (SC5.1), this improvement would be partially offset, leading to a 29% decline in aquifer storage. The scenario maintaining stable agricultural demand from the Triassic aquifer under CC (SC6.1) projected an 83% decrease in storage. Conversely, the total “Irrigation Cancellation” scenario (SC7.1) under CC showed a significant increase in aquifer storage, reaching 59.3 Mm3 by 2050—an improvement of 250% compared to the reference scenario. The study underscores the critical need for alternative water sources for irrigation and integrated management strategies to mitigate future water scarcity. Full article
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12 pages, 5345 KiB  
Article
Creation of Educational Technology Resources to Raise Awareness of Gender Violence Through a Service Learning Project
by Vanesa Delgado-Benito, Sonia Rodríguez-Cano, Miguel Ángel García-Delgado, Paula Puente-Torre, Vanesa Ausín-Villaverde and Víctor Abella-García
Societies 2025, 15(4), 91; https://doi.org/10.3390/soc15040091 - 1 Apr 2025
Viewed by 392
Abstract
This contribution is part of the Service Learning (SL) project “Abre tus ojos” (Open your eyes), whose main objective is to contribute to the coeducation and gender violence awareness of future education professionals. In line with the dimensions of sustainable human development, the [...] Read more.
This contribution is part of the Service Learning (SL) project “Abre tus ojos” (Open your eyes), whose main objective is to contribute to the coeducation and gender violence awareness of future education professionals. In line with the dimensions of sustainable human development, the actions developed in this SL project are directly related to helping people and groups in need. Students from different courses at the Faculty of Education of the University of Burgos have been involved in the training activities of an Association for Assistance to Victims of Sexual Assault and Domestic Violence (ADAVAS Burgos) through the design of technological educational resources that contribute to raising awareness of gender violence. As a result of the project, a web repository has been created with technological educational resources created by the students (videos, infographics, stories, games). This repository is open access and is presented as a resource contributing to the goal of Sustainable Development Goal (SDP) in relation to gender equality. Full article
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34 pages, 2285 KiB  
Article
Empirical Analysis of Data Sampling-Based Decision Forest Classifiers for Software Defect Prediction
by Fatima Enehezei Usman-Hamza, Abdullateef Oluwagbemiga Balogun, Hussaini Mamman, Luiz Fernando Capretz, Shuib Basri, Rafiat Ajibade Oyekunle, Hammed Adeleye Mojeed and Abimbola Ganiyat Akintola
Software 2025, 4(2), 7; https://doi.org/10.3390/software4020007 - 21 Mar 2025
Viewed by 1679
Abstract
The strategic significance of software testing in ensuring the success of software development projects is paramount. Comprehensive testing, conducted early and consistently across the development lifecycle, is vital for mitigating defects, especially given the constraints on time, budget, and other resources often faced [...] Read more.
The strategic significance of software testing in ensuring the success of software development projects is paramount. Comprehensive testing, conducted early and consistently across the development lifecycle, is vital for mitigating defects, especially given the constraints on time, budget, and other resources often faced by development teams. Software defect prediction (SDP) serves as a proactive approach to identifying software components that are most likely to be defective. By predicting these high-risk modules, teams can prioritize thorough testing and inspection, thereby preventing defects from escalating to later stages where resolution becomes more resource intensive. SDP models must be continuously refined to improve predictive accuracy and performance. This involves integrating clean and preprocessed datasets, leveraging advanced machine learning (ML) methods, and optimizing key metrics. Statistical-based and traditional ML approaches have been widely explored for SDP. However, statistical-based models often struggle with scalability and robustness, while conventional ML models face challenges with imbalanced datasets, limiting their prediction efficacy. In this study, innovative decision forest (DF) models were developed to address these limitations. Specifically, this study evaluates the cost-sensitive forest (CS-Forest), forest penalizing attributes (FPA), and functional trees (FT) as DF models. These models were further enhanced using homogeneous ensemble techniques, such as bagging and boosting techniques. The experimental analysis on benchmark SDP datasets demonstrates that the proposed DF models effectively handle class imbalance, accurately distinguishing between defective and non-defective modules. Compared to baseline and state-of-the-art ML and deep learning (DL) methods, the suggested DF models exhibit superior prediction performance and offer scalable solutions for SDP. Consequently, the application of DF-based models is recommended for advancing defect prediction in software engineering and similar ML domains. Full article
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15 pages, 1142 KiB  
Article
A Two-Step SD/SOCP-GTRS Method for Improved RSS-Based Localization in Wireless Sensor Networks
by Shengming Chang and Lincan Li
Sensors 2025, 25(6), 1837; https://doi.org/10.3390/s25061837 - 15 Mar 2025
Viewed by 528
Abstract
Wireless localization is a fundamental component of modern sensor networks, with applications spanning environmental monitoring and smart cities. Ensuring accurate and efficient localization is critical for enhancing network performance and reliability, particularly in the presence of signal attenuation and noise. This study proposes [...] Read more.
Wireless localization is a fundamental component of modern sensor networks, with applications spanning environmental monitoring and smart cities. Ensuring accurate and efficient localization is critical for enhancing network performance and reliability, particularly in the presence of signal attenuation and noise. This study proposes a novel two-step localization framework, SD/SOCP-GTRS, to improve the precision of target localization using received signal strength (RSS) measurements. In the first step (SD/SOCP), semidefinite programming (SDP) and second-order cone programming (SOCP)-based convex relaxation are applied to the maximum likelihood (ML) estimator, generating an initial coarse estimate. The second step (GTRS) refines this estimate using weighted least squares (WLS) and the generalized trust region subproblem (GTRS), mitigating performance degradation caused by relaxation. Monte Carlo simulations validate that the proposed SD/SOCP-GTRS approach effectively reduces root mean square error (RMSE) compared to other methods. These findings demonstrate that the SD/SOCP-GTRS framework consistently outperforms existing techniques, approaching the theoretical performance limit and offering a robust solution for high-precision localization in wireless sensor networks. Full article
(This article belongs to the Section Sensor Networks)
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24 pages, 19467 KiB  
Article
Spatiotemporal Heterogeneity of Vegetation Cover Dynamics and Its Drivers in Coastal Regions: Evidence from a Typical Coastal Province in China
by Yiping Yu, Dong Liu, Shiyu Hu, Xingyu Shi and Jiakui Tang
Remote Sens. 2025, 17(5), 921; https://doi.org/10.3390/rs17050921 - 5 Mar 2025
Viewed by 864
Abstract
Studying the spatiotemporal trends and influencing factors of vegetation coverage is essential for assessing ecological quality and monitoring regional ecosystem dynamics. The existing research on vegetation coverage variations and their driving factors predominantly focused on inland ecologically vulnerable regions, while coastal areas received [...] Read more.
Studying the spatiotemporal trends and influencing factors of vegetation coverage is essential for assessing ecological quality and monitoring regional ecosystem dynamics. The existing research on vegetation coverage variations and their driving factors predominantly focused on inland ecologically vulnerable regions, while coastal areas received relatively little attention. However, coastal regions, with their unique geographical, ecological, and anthropogenic activity characteristics, may exhibit distinct vegetation distribution patterns and driving mechanisms. To address this research gap, we selected Shandong Province (SDP), a representative coastal province in China with significant natural and socioeconomic heterogeneity, as our study area. To investigate the coastal–inland differentiation of vegetation dynamics and its underlying mechanisms, SDP was stratified into four geographic sub-regions: coastal, eastern, central, and western. Fractional vegetation cover (FVC) derived from MOD13A3 v061 NDVI data served as the key indicator, integrated with multi-source datasets (2000–2023) encompassing climatic, topographic, and socioeconomic variables. We analyzed the spatiotemporal characteristics of vegetation coverage and their dominant driving factors across these geographic sub-regions. The results indicated that (1) the FVC in SDP displayed a complex spatiotemporal heterogeneity, with a notable coastal–inland gradient where FVC decreased from the inland towards the coast. (2) The influence of various factors on FVC significantly varied across the sub-regions, with socioeconomic factors dominating vegetation dynamics. However, socioeconomic factors displayed an east–west polarity, i.e., their explanatory power intensified westward while resurging in coastal zones. (3) The intricate interaction of multiple factors significantly influenced the spatial differentiation of FVC, particularly dual-factor synergies where interactions between socioeconomic and other factors were crucial in determining vegetation coverage. Notably, the coastal zone exhibited a high sensitivity to socioeconomic drivers, highlighting the exceptional sensitivity of coastal ecosystems to human activities. This study provides insights into the variations in vegetation coverage across different geographical zones in coastal regions, as well as the interactions between socioeconomic and natural factors. These findings can help understand the challenges faced in protecting coastal vegetation, facilitating deeper insight into ecosystems responses and enabling the formulation of effective and tailored ecological strategies to promote sustainable development in coastal areas. Full article
(This article belongs to the Special Issue Remote Sensing in Coastal Vegetation Monitoring)
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20 pages, 2041 KiB  
Article
Top-k Shuffled Differential Privacy Federated Learning for Heterogeneous Data
by Di Xiao, Xinchun Fan and Lvjun Chen
Sensors 2025, 25(5), 1441; https://doi.org/10.3390/s25051441 - 26 Feb 2025
Cited by 1 | Viewed by 1032
Abstract
Federated learning (FL) has emerged as a promising framework for training shared models across diverse participants, ensuring data remains securely stored on local devices. Despite its potential, FL still faces some critical challenges, including data heterogeneity, privacy risks, and substantial communication overhead. Current [...] Read more.
Federated learning (FL) has emerged as a promising framework for training shared models across diverse participants, ensuring data remains securely stored on local devices. Despite its potential, FL still faces some critical challenges, including data heterogeneity, privacy risks, and substantial communication overhead. Current privacy-preserving FL research frequently fails to tackle complexities posed by heterogeneous data adequately, hence increasing communication expenses. To tackle these issues, we propose a top-k shuffled differential privacy FL (TopkSDP-FL) framework tailored to heterogeneous data environments. To address the model drift issue effectively, we design a novel regularization for local training, drawing inspiration from contrastive learning. To enhance efficiency, we propose a bidirectional top-k communication mechanism that reduces uplink and downlink overhead while strengthening privacy protection through double amplification with the shuffle model. Additionally, we shuffle all local gradient parameters at the layer level to address privacy budget concerns associated with high-dimensional aggregation and repeated iterations. Finally, a formal privacy analysis confirms the privacy amplification effect of TopkSDP-FL. The experimental results further demonstrate its superiority over other state-of-the-art FL methods, with an average accuracy improvement of 3% compared to FedAvg and other leading algorithms under the non-IID scenario, while also reducing communication costs by over 90%. Full article
(This article belongs to the Special Issue Federated and Distributed Learning in IoT)
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15 pages, 9200 KiB  
Article
Dynamics Model of a Multi-Rotor UAV Propeller and Its Fault Detection
by Yongtian Zou, Haiting Xia, Xinmin Yang, Peigen Li and Yu Yi
Drones 2025, 9(3), 176; https://doi.org/10.3390/drones9030176 - 26 Feb 2025
Viewed by 1179
Abstract
The propeller state of unmanned aerial vehicles (UAV) is difficult to detect in real time due to trouble with laying out the sensor and multiple signal sources. To solve this problem, a fault detection method for multi-rotor UAV propellers was proposed based on [...] Read more.
The propeller state of unmanned aerial vehicles (UAV) is difficult to detect in real time due to trouble with laying out the sensor and multiple signal sources. To solve this problem, a fault detection method for multi-rotor UAV propellers was proposed based on a signal analysis of the built-in inertial measurement unit (IMU). Firstly, the multi-source coupled signals of the UAV flight were obtained through the ground station. Then, the picked-up signals were optimally separated according to the multi-rotor UAV propeller fault dynamics model, and signals rich in fault information were obtained. Finally, the separated signals were calculated using the symmetrized dot pattern (SDP), and then the similarity index was used to quantify the distribution of the signal in the feature plot to realize propeller fault detection. The OTSU algorithm was used to quantify the detection results, yielding a similarity of 76.2% in the z-axis direction, which is better than the values in the other two directions. The simulation and experimental analysis of the propeller failure dynamics model showed that the proposed method can effectively identify the propeller faults of multi-rotor UAVs. Full article
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21 pages, 783 KiB  
Article
Robust Beamfocusing for Secure NFC with Imperfect CSI
by Weijian Chen, Zhiqiang Wei and Zai Yang
Sensors 2025, 25(4), 1240; https://doi.org/10.3390/s25041240 - 18 Feb 2025
Viewed by 744
Abstract
In this paper, we consider the issue of the physical layer security (PLS) problem between two nodes, i.e., transmitter (Alice) and receiver (Bob), in the presence of an eavesdropper (Eve) in a near-field communication (NFC) system. Notably, massive multiple-input multiple-output (MIMO) arrays significantly [...] Read more.
In this paper, we consider the issue of the physical layer security (PLS) problem between two nodes, i.e., transmitter (Alice) and receiver (Bob), in the presence of an eavesdropper (Eve) in a near-field communication (NFC) system. Notably, massive multiple-input multiple-output (MIMO) arrays significantly increase array aperture, thereby rendering the eavesdroppers more inclined to lurk near the transmission end. This situation necessitates using near-field channel models to more accurately describe channel characteristics. We consider two schemes with imperfect channel estimation information (CSI). The first scheme involves a conventional multiple-input multiple-output multiple-antenna eavesdropper (MIMOME) setup, where Alice simultaneously transmits information signal and artificial noise (AN). In the second scheme, Bob operates in a full-duplex (FD) mode, with Alice transmitting information signal while Bob emits AN. We then jointly design beamforming and AN vectors to degrade the reception signal quality at Eve, based on the signal-to-interference-plus-noise ratio (SINR) of each node. To tackle the power minimization problem, we propose an iterative algorithm that includes an additional constraint to ensure adherence to specified quality-of-service (QoS) metrics. Additionally, we decompose the robust optimization problem of the two schemes into two sub-problems, with one that can be solved using generalized Rayleigh quotient methods and the other that can be addressed through semi-definite programming (SDP). Finally, our simulation results confirm the viability of the proposed approach and demonstrate the effectiveness of the protection zone for NFC systems operating with CSI. Full article
(This article belongs to the Special Issue Secure Communication for Next-Generation Wireless Networks)
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18 pages, 6091 KiB  
Article
The Impact of Social Distancing Policies on Water Distribution Systems During COVID-19: The Case of Maringá, Brazil
by Bruna Forestieri Bolonhez, André Rodrigues da Silva, Juliana Gomes Costa Paulo, Carolina Fiamonzini Flores and Hemerson Donizete Pinheiro
Urban Sci. 2025, 9(2), 39; https://doi.org/10.3390/urbansci9020039 - 10 Feb 2025
Viewed by 677
Abstract
Effective water management is crucial for ensuring water security and addressing supply crises. This study evaluates how Social Distancing Policies (SDPs), implemented during the COVID-19 pandemic influenced water net inflow patterns in the supply system of Maringá, Brazil. Using a limited dataset, hourly [...] Read more.
Effective water management is crucial for ensuring water security and addressing supply crises. This study evaluates how Social Distancing Policies (SDPs), implemented during the COVID-19 pandemic influenced water net inflow patterns in the supply system of Maringá, Brazil. Using a limited dataset, hourly water intake and net inflow data were analyzed across nine supply zones with distinct regional characteristics (e.g., residential and commercial areas), highlighting changes in water demand driven by SDPs and climatic variables. Results indicate an increase in net inflow in residential zones of 1.87% to 8.44%, while commercial zones experienced a decrease of up to 6.41%. Station arity tests confirmed long-term stability in most zones, with notable variability in residential areas. Multiple regression analysis revealed that the effects of temperature had the most significant influence on net inflow, surpassing the effects of precipitation and SDPs. These findings suggest that SDPs and health-related factors play a minor role in water distribution planning compared to climate variables, emphasizing the need for tailored strategies that account for regional characteristics and support decision-making in resource-constrained environments. Full article
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