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The wind-solar-load correlation model is the basis for accurately evaluating the reliability of offshore wind power-photovoltaic-energy storage grid connected system. To solve the problem of high-dimensional wind-solar-load correlation modeling, a hybrid time-varying Copula model based on vine structure was proposed. By combining the actual wind farm output, photovoltaic power station output and grid load data, eight wind-solar-load combined Copula models were established, and the proposed model had more advantages than other models by using two common evaluation criteria of optimal model. Taking the measured data of wind farms and photovoltaic stations in Shandong province as examples, eight groups of models were analyzed and compared in IEEE-RTS79 system with wind farms and photovoltaic stations. The results show that the proposed Copula function model can more accurately describe the multi-dimensional wind-solar-load correlation. However, other existing models underestimate the impact of the wind-solar-load correlation on system reliability. After adding the energy storage device to the test system, other models also have deviations in the selection of the optimal wind-solar installed capacity ratio, the selection of storage power station capacity and the evaluation of power fluctuation.

Timely and accurate tree species mapping is crucial for forest resource inventory, supporting management, conservation biology, and ecological restoration. This study utilized Sentinel-1 and Sentinel-2 data to classify five dominant tree species in Chengde and Beijing. To effectively capture the influence of multi-temporal data, data were acquired in March, June, September, and December 2020, extracting various features, including bands, spectral indices, texture features, and topographic variables. The optimal input variable combination was explored using 1519 field survey samples for training and testing datasets. Classification employed Random Forest, XGBoost, and deep learning models, with performance evaluated through out-of-bag estimation and cross-validation. The XGBoost model achieved the highest accuracy of 81.25% (kappa = 0.74) when using Sentinel-1 and Sentinel-2 bands, indices, texture features, and DEM data. Results demonstrate the effectiveness of using Sentinel data for tree species classification and emphasize the value of machine learning algorithms. This study underscores the potential of combining synthetic aperture radar (SAR) and optical data for large-scale tree species classification, with significant implications for forest monitoring and management. [ABSTRACT FROM AUTHOR]

Ecological vulnerability assessment is crucial for environment protection, ecological restoration and resource utilization. However, many former studies have limitations in the indicator system of the assessment, which were not comparable for different types of ecologically vulnerable areas. It is difficult to apply directly to the ecological vulnerability assessment of different types and in various regions. Aiming to solve these problems, the study proposed a well-established and comprehensive indicator system for ecological vulnerability assessment and conducted ecological vulnerability assessment application of five types of typical ecologically vulnerable areas of China based on remote sensing, meteorological, geographic and other data. The results show that the average EVIs value of Zhangbei County ranging from 0.525 to 0.559 are the highest among the five research areas during the four periods, followed by Zoige region and Xiamen bay. However, the region with the lowest average EVI value varies. In 2005 and 2015, it was Taihe County, while in 2010 and 2020, it was the Sanjiangyuan region. The variation of average EVIs in the five typical areas presents slight fluctuation and remains generally stable from 2005 to 2020. It indicates that the environmental protection measures and projects undertaken by the Chinese government in recent years have had a striking effect, curbing the trend of ecological environment deterioration. [ABSTRACT FROM AUTHOR]

In this study, a deep learning-based system for apple defect detection and quality grading was developed, integrating various advanced image-processing technologies and machine learning algorithms to enhance the automation and accuracy of apple quality monitoring. Experimental validation demonstrated the superior performance of the proposed model in handling complex image tasks. In the defect-segmentation experiments, the method achieved a precision of 93%, a recall of 90%, an accuracy of 91% and a mean Intersection over Union (mIoU) of 92%, significantly surpassing traditional deep learning models such as U-Net, SegNet, PSPNet, UNet++, DeepLabv3+ and HRNet. Similarly, in the quality-grading experiments, the method exhibited high efficiency with a precision of 91%, and both recall and accuracy reaching 90%. Additionally, ablation experiments with different loss functions confirmed the significant advantages of the Jump Loss in enhancing model performance, particularly in addressing class imbalance and improving feature learning. These results not only validate the effectiveness and reliability of the system in practical applications but also highlight its potential in automating the detection and grading processes in the apple industry. This integration of advanced technologies provides a new automated solution for quality control of agricultural products like apples, facilitating the modernization of agricultural production. [ABSTRACT FROM AUTHOR]

A novel deep learning model, DiffuCNN, is introduced in this paper, specifically designed for counting tobacco lesions in complex agricultural settings. By integrating advanced image processing techniques with deep learning methodologies, the model significantly enhances the accuracy of detecting tobacco lesions under low-resolution conditions. After detecting lesions, the grading of the disease severity is achieved through counting. The key features of DiffuCNN include a resolution enhancement module based on diffusion, an object detection network optimized through filter pruning, and the employment of the CentralSGD optimization algorithm. Experimental results demonstrate that DiffuCNN surpasses other models in precision, with respective values of 0.98 on precision, 0.96 on recall, 0.97 on accuracy, and 62 FPS. Particularly in counting tobacco lesions, DiffuCNN exhibits an exceptional performance, attributable to its efficient network architecture and advanced image processing techniques. The resolution enhancement module based on diffusion amplifies minute details and features in images, enabling the model to more effectively recognize and count tobacco lesions. Concurrently, filter pruning technology reduces the model's parameter count and computational burden, enhancing the processing speed while retaining the capability to recognize key features. The application of the CentralSGD optimization algorithm further improves the model's training efficiency and final performance. Moreover, an ablation study meticulously analyzes the contribution of each component within DiffuCNN. The results reveal that each component plays a crucial role in enhancing the model performance. The inclusion of the diffusion module significantly boosts the model's precision and recall, highlighting the importance of optimizing at the model's input end. The use of filter pruning and the CentralSGD optimization algorithm effectively elevates the model's computational efficiency and detection accuracy. [ABSTRACT FROM AUTHOR]

Long-term exposure to high concentrations of fine particles can cause irreversible damage to people's health. Therefore, it is of extreme significance to conduct large-scale continuous spatial fine particulate matter (PM2.5) concentration prediction for air pollution prevention and control in China. The distribution of PM2.5 ground monitoring stations in China is uneven with a larger number of stations in southeastern China, while the number of ground monitoring sites is also insufficient for air quality control. Remote sensing technology can obtain information quickly and macroscopically. Therefore, it is possible to predict PM2.5 concentration based on multi-source remote sensing data. Our study took China as the research area, using the Pearson correlation coefficient and GeoDetector to select auxiliary variables. In addition, a long short-term memory neural network and random forest regression model were established for PM2.5 concentration estimation. We finally selected the random forest regression model (R2 = 0.93, RMSE = 4.59 μg m−3) as our prediction model by the model evaluation index. The PM2.5 concentration distribution across China in 2021 was estimated, and then the influence factors of high-value regions were explored. It is clear that PM2.5 concentration is not only related to the local geographical and meteorological conditions, but also closely related to economic and social development. [ABSTRACT FROM AUTHOR]

Stabilization pretreatment coupled with molecular cross-linking is commonly used to modify starch, aiming to obtain starch-based hard carbon materials with appropriate spherical particle sizes. Nevertheless, the impact of the intermediate stabilization process on its sodium storage performance remains unclear. Herein, a hard carbon material with no surface open pores, low specific surface area and abundant internal closed pores with thinner pore walls is successfully synthesized and exhibits significantly improved initial Coulombic efficiency and plateau capacity through a simple low-temperature pretreatment strategy, using renewable and cost-effective soluble starch as the raw material. Additionally, research indicates that an appropriate degree of disorder or defectiveness is conducive to forming a larger quantity of closed pores with thinner pore walls. Both excessively low and high defect levels are detrimental to the formation of closed pores. This work will encourage researchers to further focus on the impact of defectiveness on closed pores, which will promote the development of high-energy practical sodium-ion batteries. [Display omitted] • Folding-bending of graphite-like microcrystals helps create more closed pores. • Further folding will lead to the restacking of graphite-like microcrystals. • Both excessive low and high defect levels are detrimental to forming closed pores. [ABSTRACT FROM AUTHOR]