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Search Results (209)

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15 pages, 2776 KiB  
Article
Research on a Target Detection Algorithm for Common Pests Based on an Improved YOLOv7-Tiny Model
by He Gong, Xiaodan Ma and Ying Guo
Agronomy 2024, 14(12), 3068; https://doi.org/10.3390/agronomy14123068 (registering DOI) - 23 Dec 2024
Abstract
In agriculture and forestry, pest detection is critical for increasing crop yields and reducing economic losses. However, traditional deep learning models face challenges in resource-constrained environments, such as insufficient accuracy, slow inference speed, and large model sizes, which hinder their practical application. To [...] Read more.
In agriculture and forestry, pest detection is critical for increasing crop yields and reducing economic losses. However, traditional deep learning models face challenges in resource-constrained environments, such as insufficient accuracy, slow inference speed, and large model sizes, which hinder their practical application. To address these issues, this study proposes an improved YOLOv7-tiny model designed to deliver efficient, accurate, and lightweight pest detection solutions. The main improvements are as follows: 1. Lightweight Network Design: The backbone network is optimized by integrating GhostNet and Dynamic Region-Aware Convolution (DRConv) to enhance computational efficiency. 2. Feature Sharing Enhancement: The introduction of a Cross-layer Feature Sharing Network (CotNet Transformer) strengthens feature fusion and extraction capabilities. 3. Activation Function Optimization: The traditional ReLU activation function is replaced with the Gaussian Error Linear Unit (GELU) to improve nonlinear expression and classification performance. Experimental results demonstrate that the improved model surpasses YOLOv7-tiny in accuracy, inference speed, and model size, achieving a [email protected] of 92.8%, reducing inference time to 4.0 milliseconds, and minimizing model size to just 4.8 MB. Additionally, compared to algorithms like Faster R-CNN, SSD, and RetinaNet, the improved model delivers superior detection performance. In conclusion, the improved YOLOv7-tiny provides an efficient and practical solution for intelligent pest detection in agriculture and forestry. Full article
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<p>The workflow overview of the improved model.</p>
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<p>Dataset actual image: (<b>a</b>) beet_army_worm; (<b>b</b>) beet_spot_flies; (<b>c</b>) beet_weevil; (<b>d</b>) blister_beetle; (<b>e</b>) brown_plant_hopper; (<b>f</b>) cicadella_viridis; (<b>g</b>) legume_blister_beetle; (<b>h</b>) limacodidae; (<b>i</b>) lycorma_delicatula; (<b>j</b>) miridae; (<b>k</b>) mole_cricket; (<b>l</b>) papilio_xuthus; (<b>m</b>) pieris_canidia; (<b>n</b>) red_spider; (<b>o</b>) rice_gall_midge; (<b>p</b>) rice_water_weevil; (<b>q</b>) sericaorient_alismots_chulsky; (<b>r</b>) small_brown_plant_hopper; (<b>s</b>) white_backed_plant_hopper; (<b>t</b>) wireworm; and (<b>u</b>) yellow_rice_borer.</p>
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<p>The improved model structure.</p>
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<p>The structure of Ghostnet module.</p>
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<p>The structure of DRConv Network.</p>
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<p>GELU function image.</p>
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<p>Visual result map: (<b>a</b>) beet_army_worm; (<b>b</b>) beet_spot_flies; (<b>c</b>) beet_weevil; (<b>d</b>) blister_beetle; (<b>e</b>) brown_plant_hopper; (<b>f</b>) cicadella_viridis; (<b>g</b>) legume_blister_beetle; (<b>h</b>) limacodidae; (<b>i</b>) lycorma_delicatula; (<b>j</b>) miridae; (<b>k</b>) mole_cricket; (<b>l</b>) papilio_xuthus; (<b>m</b>) pieris_canidia; (<b>n</b>) red_spider; (<b>o</b>) rice_gall_midge; (<b>p</b>) rice_water_weevil; (<b>q</b>) sericaorient_alismots_chulsky; (<b>r</b>) small_brown_plant_hopper; (<b>s</b>) white_backed_plant_hopper; (<b>t</b>) wireworm; and (<b>u</b>) yellow_rice_borer.</p>
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18 pages, 8161 KiB  
Article
A Significant Wave Height Prediction Method Based on Improved Temporal Convolutional Network and Attention Mechanism
by Ying Han, Jiaxin Tang, Hongyun Jia, Changming Dong and Ruihan Zhao
Electronics 2024, 13(24), 4879; https://doi.org/10.3390/electronics13244879 - 11 Dec 2024
Viewed by 365
Abstract
Wave prediction is crucial for ensuring the safety and disaster mitigation of coastal areas, helping to support marine economic activities. Currently, many deep learning models, such as the temporal convolutional network (TCN), have been applied to wave prediction. In this study, a prediction [...] Read more.
Wave prediction is crucial for ensuring the safety and disaster mitigation of coastal areas, helping to support marine economic activities. Currently, many deep learning models, such as the temporal convolutional network (TCN), have been applied to wave prediction. In this study, a prediction model based on improved TCN-Attention (ITCN-A) is proposed. This model incorporates improvements in two aspects. Firstly, to address the difficulty of calibrating hyperparameters in traditional TCN models, a whale optimization algorithm (WOA) has been introduced to achieve global optimization of hyperparameters. Secondly, we integrate dynamic ReLU to implement an adaptive activation function. The improved TCN is then combined with the attention mechanism to further enhance the extraction of long-term features of wave height. We conducted experiments using data from three buoy stations with varying water depths and geographical locations, covering prediction lead times ranging from 1 h to 24 h. The results demonstrate that the proposed integrated model reduces the RMSE of prediction by 12.1% and MAE by an 18.6% compared with the long short-term memory (LSTM) model. Consequently, this model effectively improves the accuracy of wave height predictions at different stations, verifying its effectiveness and general applicability. Full article
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<p>Causal convolutional structure figure.</p>
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<p>Improved TCN block.</p>
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<p>Attention mechanism figure.</p>
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<p>Structure of proposed method.</p>
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<p>Selected buoy station location.</p>
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<p>Fitness value iteration curve.</p>
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<p>Prediction performance of different models at station 41008.</p>
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<p>Comparison of 1 h predicted values of different models at station 41008.</p>
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<p>Comparison of 3 h predicted values of different models at station 41008.</p>
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<p>Comparison of 6 h predicted values of different models at station 41008.</p>
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<p>Long-term predictive performance of different models.</p>
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<p>Scatter plot of station 42055’s prediction results.</p>
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<p>Scatter plot of station 46083’s prediction results.</p>
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22 pages, 4876 KiB  
Article
Innovative Ghost Channel Spatial Attention Network with Adaptive Activation for Efficient Rice Disease Identification
by Yang Zhou, Yang Yang, Dongze Wang, Yuting Zhai, Haoxu Li and Yanlei Xu
Agronomy 2024, 14(12), 2869; https://doi.org/10.3390/agronomy14122869 - 1 Dec 2024
Viewed by 489
Abstract
To address the computational complexity and deployment challenges of traditional convolutional neural networks in rice disease identification, this paper proposes an efficient and lightweight model: Ghost Channel Spatial Attention ShuffleNet with Mish-ReLU Adaptive Activation Function (GCA-MiRaNet). Based on ShuffleNet V2, we effectively reduced [...] Read more.
To address the computational complexity and deployment challenges of traditional convolutional neural networks in rice disease identification, this paper proposes an efficient and lightweight model: Ghost Channel Spatial Attention ShuffleNet with Mish-ReLU Adaptive Activation Function (GCA-MiRaNet). Based on ShuffleNet V2, we effectively reduced the model’s parameter count by streamlining convolutional layers, decreasing stacking depth, and optimizing output channels. Additionally, the model incorporates the Ghost Module as a replacement for traditional 1 × 1 convolutions, further reducing computational overhead. Innovatively, we introduce a Channel Spatial Attention Mechanism (CSAM) that significantly enhances feature extraction and generalization aimed at rice disease detection. Through combining the advantages of Mish and ReLU, we designed the Mish-ReLU Adaptive Activation Function (MAAF), enhancing the model’s generalization capacity and convergence speed. Through transfer learning and ElasticNet regularization, the model’s accuracy has notably improved while effectively avoiding overfitting. Sufficient experimental results indicate that GCA-MiRaNet attains a precision of 94.76% on the rice disease dataset, with a 95.38% reduction in model parameters and a compact size of only 0.4 MB. Compared to traditional models such as ResNet50 and EfficientNet V2, GCA-MiRaNet demonstrates significant advantages in overall performance, especially on embedded devices. This model not only enables efficient and accurate real-time disease monitoring but also provides a viable solution for rice field protection drones and Internet of Things management systems, advancing the process of contemporary agricultural smart management. Full article
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<p>The procedure for researching the rice recognition method utilizing GCA-MiRaNet.</p>
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<p>Examples of rice disease datasets. (<b>a</b>) Examples of four types of rice disease images from the public dataset; (<b>b</b>) Examples of two types of rice disease images from our self-built dataset.</p>
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<p>Demonstration of the results for different data augmentation techniques. (<b>a</b>) Results of data augmentation on public dataset; (<b>b</b>) Results of data augmentation on self-built dataset.</p>
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<p>Structural diagram of GCA-MiRaNet.</p>
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<p>Structural diagram of GCA-MiRaNet. (<b>a</b>) Basic unit; (<b>b</b>) Downsampling unit.</p>
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<p>Structure of the Ghost Module. The colors in the figure differentiate the feature maps in the Ghost module’s stages: green for initial convolution features, yellow and brown blocks indicate the feature maps generated by the Ghost operation, and the final block is the aggregated output of these feature maps.</p>
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<p>Structural diagram of the CSAM attention mechanism.</p>
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<p>Comparative analysis of different activation functions.</p>
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<p>Confusion matrix of GCA-MiRaNet.</p>
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<p>Comparison results of heatmaps. The colors in the image represent the model’s level of interest in different areas, with warmer colors indicating higher attention from the model.</p>
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<p>Validation accuracy comparison among different models.</p>
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<p>Validation loss comparison among different models.</p>
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<p>Visual results of the accuracy testing of GCA-MiRaNet for rice disease identification on an embedded platform. (<b>a</b>) Results for Bacterial Blight; (<b>b</b>) Results for Brown spot; (<b>c</b>) Results for Rice blast; (<b>d</b>) Results for Rice tungro.</p>
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25 pages, 6447 KiB  
Article
ReLU, Sparseness, and the Encoding of Optic Flow in Neural Networks
by Oliver W. Layton, Siyuan Peng and Scott T. Steinmetz
Sensors 2024, 24(23), 7453; https://doi.org/10.3390/s24237453 - 22 Nov 2024
Viewed by 534
Abstract
Accurate self-motion estimation is critical for various navigational tasks in mobile robotics. Optic flow provides a means to estimate self-motion using a camera sensor and is particularly valuable in GPS- and radio-denied environments. The present study investigates the influence of different activation functions—ReLU, [...] Read more.
Accurate self-motion estimation is critical for various navigational tasks in mobile robotics. Optic flow provides a means to estimate self-motion using a camera sensor and is particularly valuable in GPS- and radio-denied environments. The present study investigates the influence of different activation functions—ReLU, leaky ReLU, GELU, and Mish—on the accuracy, robustness, and encoding properties of convolutional neural networks (CNNs) and multi-layer perceptrons (MLPs) trained to estimate self-motion from optic flow. Our results demonstrate that networks with ReLU and leaky ReLU activation functions not only achieved superior accuracy in self-motion estimation from novel optic flow patterns but also exhibited greater robustness under challenging conditions. The advantages offered by ReLU and leaky ReLU may stem from their ability to induce sparser representations than GELU and Mish do. Our work characterizes the encoding of optic flow in neural networks and highlights how the sparseness induced by ReLU may enhance robust and accurate self-motion estimation from optic flow. Full article
(This article belongs to the Section Navigation and Positioning)
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<p>Sample optic flow fields generated with different simulated camera self-motion through different visual environments. (<b>a</b>) Backward translation at 1 m/s at −180° azimuth and 45° elevation away from a frontoparallel wall positioned 4 m in front of the camera. (<b>b</b>) Combination of backward translation at 1 m/s (−180° azimuth, 45° elevation) with respect to a ground plane and 5°/s yaw rotation. The camera is 10 m above the ground plane and is oriented 30° downward. (<b>c</b>) Forward translation at 1 m/s at 0° azimuth and 0° elevation through a 3D dot cloud.</p>
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<p>Neural network activation functions examined in the present article. (<b>a</b>) The rectified linear unit (ReLU) and leaky ReLU activation functions. (<b>b</b>) The Gaussian error linear unit (GELU) and Mish activation functions. The y-axis shows the output of the neuron after applying an activation function to the net input indicated on the x-axis.</p>
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<p>Overview of the CNN and MLP network architecture. The CNN architecture begins with one or more convolutional and max pooling layer stacks. The max pooling layers that reduce the spatial resolution of the optic flow signal. The representation in the final max pooling layer is flattened into a 1D vector, which is passed through one or more densely connected layers. As described in the main text, we created CNN and MLP variants that apply one of the following activation functions in both the convolutional and dense layers: ReLU, leaky ReLU, GELU, or Mish. We schematize where in the network the choice of one of these activation functions is applied with &lt;Act fun&gt;. The output layer contains five neurons, corresponding to the parameters that describe the camera’s self-motion: the azimuth and elevation of observer translation, along with the pitch, yaw, and roll components of observer rotation. The network is trained to minimize a cosine loss function of the translation azimuth angle due to its circularity. Mean squared error (MSE) is used for the other variables. The MLP differs from the CNN in the lack of convolutional and max pooling stages (shown in teal).</p>
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<p>Test accuracy of the neural networks on the TR360 dataset. (<b>a</b>,<b>c</b>) MSE of network estimates of translational (T) and rotational (R) self-motion from optic flow (<b>b</b>,<b>d</b>) mean absolute error (MAE) of networks estimates of the T and R self-motion from optic flow. (<b>e</b>–<b>h</b>) Scatter plots depict the estimate (y-axis) corresponding to each true translational azimuth label (x-axis; “heading_x”) produced by each CNN variant. Each red diagonal line coincides with estimates that match the true label (no error). (<b>i</b>–<b>l</b>) Same format as the row above, but for the MLPs. In the depicted coordinate system, ±180° both refer to straight-backward self-motion.</p>
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<p>Test accuracy on the TR360Cloud optic flow dataset achieved by the CNN and MLP models trained on a different dataset (TR360). Same format and conventions as <a href="#sensors-24-07453-f004" class="html-fig">Figure 4</a>.</p>
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<p>Accuracy of self-motion estimates when noise is added to the TR360 test optic flow samples. (<b>a</b>–<b>c</b>) Example optic flow fields with 0%, 30%, and 60% noise, respectively. (<b>d</b>,<b>e</b>) MAE in estimating translational and rotational self-motion parameters, respectively, when the optic flow contains different proportions of noise (x-axis).</p>
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<p>Accuracy of self-motion estimates when motion vectors are removed from the TR360 test optic flow samples. (<b>a</b>–<b>c</b>) Example optic flow fields with 0%, 30%, and 60% sparseness, respectively. (<b>d</b>,<b>e</b>) MAE in estimating translational and rotational self-motion parameters, respectively. The x-axis indicates the degree of sparseness within each optic flow sample.</p>
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<p>Accuracy of self-motion estimates when the optic flow contains the motion due to an independently moving object. (<b>a</b>–<b>c</b>) Example optic flow fields with a Size 1 (1 × 1 pixels), Size 6 (6 × 6 pixels), and Size 12 (12 × 12 pixels) region of motion induced by the moving object, respectively. (<b>d</b>,<b>e</b>) MAE in estimating translational and rotational self-motion parameters, respectively. The x-axis indicates the size of the moving object in the optic flow field.</p>
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<p>(<b>a</b>–<b>h</b>) The population (red) and lifetime (blue) sparseness in each layer of the 8 models. Both metrics range between 0 (dense code) and 1 (very sparse code). The red and blue dashed lines indicate the mean population and lifetime sparseness across the network, respectively.</p>
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<p>(<b>a</b>–<b>d</b>) The relationship between population sparseness (x-axis) and MAE obtained when estimating the translational self-motion parameters on the TR360Cloud dataset (y-axis). Plot markers correspond to values obtained from the top 3 networks within each model type. Red lines show the regression curves fitted to the data.</p>
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<p>The Sparseness Index (<span class="html-italic">S</span>) computed on the weights in the early, middle, or final third of the CNNs (<b>a</b>,<b>c</b>) and MLPs (<b>b</b>,<b>d</b>). Solid line demarcates that the analysis includes negative network weights. Dashed line demarcates that the analysis includes only non-negative network weights.</p>
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<p>The distribution of translation azimuth angles that yield maximal activation in individual neurons within each dense hidden layer. Each histogram corresponds to the preferences of units in a single model layer, and the histograms associated with the same model are stacked vertically. Histograms assigned smaller “Dense layer” integer labels (top-left panel) correspond to layers earlier in the network, while those with larger integer labels correspond to layers deeper in the network. The x-axis in each histogram corresponds to the preferred translation azimuth angle (0–360°). The y-axis indicates the number of units that possess a particular azimuth angle (bin width: 30°). The schematic atop the 3rd column shows the coordinate system (top-down view).</p>
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<p>The translation elevation angle preference of individual neurons within each model dense hidden layer. Same format as <a href="#sensors-24-07453-f012" class="html-fig">Figure 12</a>. The schematic atop the 3rd column shows the coordinate system (side view).</p>
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<p>The distribution of preferred rotation azimuth angles of individual neurons within each model dense hidden layer. Same format as <a href="#sensors-24-07453-f012" class="html-fig">Figure 12</a>.</p>
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<p>The distribution of preferred rotation elevation angles of individual neurons within each model dense hidden layer. Same format as <a href="#sensors-24-07453-f012" class="html-fig">Figure 12</a>.</p>
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13 pages, 2625 KiB  
Article
DeepAT: A Deep Learning Wheat Phenotype Prediction Model Based on Genotype Data
by Jiale Li, Zikang He, Guomin Zhou, Shen Yan and Jianhua Zhang
Agronomy 2024, 14(12), 2756; https://doi.org/10.3390/agronomy14122756 - 21 Nov 2024
Viewed by 529
Abstract
Genomic selection serves as an effective way for crop genetic breeding, capable of significantly shortening the breeding cycle and improving the accuracy of breeding. Phenotype prediction can help identify genetic variants associated with specific phenotypes. This provides a data-driven selection criterion for genomic [...] Read more.
Genomic selection serves as an effective way for crop genetic breeding, capable of significantly shortening the breeding cycle and improving the accuracy of breeding. Phenotype prediction can help identify genetic variants associated with specific phenotypes. This provides a data-driven selection criterion for genomic selection, making the selection process more efficient and targeted. Deep learning has become an important tool for phenotype prediction due to its abilities in automatic feature learning, nonlinear modeling, and high-dimensional data processing. Current deep learning models have improvements in various aspects, such as predictive performance and computation time, but they still have limitations in capturing the complex relationships between genotype and phenotype, indicating that there is still room for improvement in the accuracy of phenotype prediction. This study innovatively proposes a new method called DeepAT, which mainly includes an input layer, a data feature extraction layer, a feature relationship capture layer, and an output layer. This method can predict wheat yield based on genotype data and has innovations in the following four aspects: (1) The data feature extraction layer of DeepAT can extract representative feature vectors from high-dimensional SNP data. By introducing the ReLU activation function, it enhances the model’s ability to express nonlinear features and accelerates the model’s convergence speed; (2) DeepAT can handle high-dimensional and complex genotype data while retaining as much useful information as possible; (3) The feature relationship capture layer of DeepAT effectively captures the complex relationships between features from low-dimensional features through a self-attention mechanism; (4) Compared to traditional RNN structures, the model training process is more efficient and stable. Using a public wheat dataset from AGT, comparative experiments with three machine learning and six deep learning methods found that DeepAT exhibited better predictive performance than other methods, achieving a prediction accuracy of 99.98%, a mean squared error (MSE) of only 28.93 tones, and a Pearson correlation coefficient close to 1, with yield predicted values closely matching observed values. This method provides a new perspective for deep learning-assisted phenotype prediction and has great potential in smart breeding. Full article
(This article belongs to the Section Precision and Digital Agriculture)
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<p>The proposed DeepAT framework. (<b>a</b>) Dataset sources, (<b>b</b>) genotype data processing, (<b>c</b>) allele encoding, (<b>d</b>) experimental procedure, (<b>e</b>) data feature extraction layer, (<b>f</b>) feature relationship capture layer, (<b>g</b>) DeepAT model architecture.</p>
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<p>Training loss variation comparison of DeepAT with the other genotype prediction methods.</p>
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<p>Prediction accuracy comparison of DeepAT with the other genotype prediction methods with different evaluation metrics.</p>
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<p>Correlation between yield predicted and observed values comparison of DeepAT with the other genotype prediction methods.</p>
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19 pages, 5047 KiB  
Article
A Convolutional Neural Network for the Removal of Simultaneous Ocular and Myogenic Artifacts from EEG Signals
by Maryam Azhar, Tamoor Shafique and Anas Amjad
Electronics 2024, 13(22), 4576; https://doi.org/10.3390/electronics13224576 - 20 Nov 2024
Viewed by 809
Abstract
Electroencephalography (EEG) is a non-invasive technique widely used in neuroscience to diagnose neural disorders and analyse brain activity. However, ocular and myogenic artifacts from eye movements and facial muscle activity often contaminate EEG signals, compromising signal analysis accuracy. While deep learning models are [...] Read more.
Electroencephalography (EEG) is a non-invasive technique widely used in neuroscience to diagnose neural disorders and analyse brain activity. However, ocular and myogenic artifacts from eye movements and facial muscle activity often contaminate EEG signals, compromising signal analysis accuracy. While deep learning models are a popular choice for denoising EEG signals, most focus on removing either ocular or myogenic artifacts independently. This paper introduces a novel EEG denoising model capable of handling the simultaneous occurrence of both artifacts. The model uses convolutional layers to extract spatial features and a fully connected layer to reconstruct clean signals from learned features. The model integrates the Adam optimiser, average pooling, and ReLU activation to effectively capture and restore clean EEG signals. It demonstrates superior performance, achieving low training and validation losses with a significantly reduced RRMSE value of 0.35 in both the temporal and spectral domains. A high cross-correlation coefficient of 0.94 with ground-truth EEG signals confirms the model’s fidelity. Compared to the existing architectures and models (FPN, UNet, MCGUNet, LinkNet, MultiResUNet3+, Simple CNN, Complex CNN) across a range of signal-to-noise ratio values, the model shows superior performance for artifact removal. It also mitigates overfitting, underscoring its robustness in artifact suppression. Full article
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<p>Artifacts in EEG: (<b>a</b>) eye movement, (<b>b</b>) eye blinks, and (<b>c</b>) muscle tension [<a href="#B18-electronics-13-04576" class="html-bibr">18</a>].</p>
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<p>Framework for simultaneous EOG-EMG artifact removal.</p>
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<p>Noisy EEG signal synthesis.</p>
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<p>Example segment of simultaneous EOG- and EMG-corrupted EEG signal and ground-truth EEG signal.</p>
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<p>Network structure for the denoising model.</p>
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<p>EEG signal dimensions in each layer.</p>
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<p>Training and validation loss curves for the proposed model.</p>
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<p>Training and validation loss curves for Complex CNN and Simple CNN.</p>
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<p>Power ratios for various frequency bands for denoised, EOG-EMG-contaminated, and clean EEG signals.</p>
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<p>Temporal representation of denoised, EOG-EMG-contaminated, and clean EEG signals.</p>
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<p>Spectral representation of denoised, EOG-EMG-contaminated, and clean EEG signals.</p>
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<p>A comparison of estimated performance metrics (<math display="inline"><semantics> <mrow> <mi>C</mi> <mi>C</mi> <mo>,</mo> <mo> </mo> <mi>R</mi> <mi>R</mi> <mi>M</mi> <mi>S</mi> <mi>E</mi> </mrow> </semantics></math> in time and frequency domains) across different <math display="inline"><semantics> <mrow> <mi>S</mi> <mi>N</mi> <mi>R</mi> </mrow> </semantics></math> values.</p>
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<p>Comparison of performance between the proposed model and the existing models.</p>
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16 pages, 8947 KiB  
Article
Research on Personnel Image Segmentation Based on MobileNetV2 H-Swish CBAM PSPNet in Search and Rescue Scenarios
by Di Zhao, Weiwei Zhang and Yuxing Wang
Appl. Sci. 2024, 14(22), 10675; https://doi.org/10.3390/app142210675 - 19 Nov 2024
Viewed by 481
Abstract
In post-disaster search and rescue scenarios, the accurate image segmentation of individuals is essential for efficient resource allocation and effective rescue operations. However, challenges such as image blur and limited resources complicate personnel segmentation. This paper introduces an enhanced, lightweight version of the [...] Read more.
In post-disaster search and rescue scenarios, the accurate image segmentation of individuals is essential for efficient resource allocation and effective rescue operations. However, challenges such as image blur and limited resources complicate personnel segmentation. This paper introduces an enhanced, lightweight version of the Pyramid Scene Parsing Network (MHC-PSPNet). By substituting ResNet50 with the more efficient MobileNetV2 as the model backbone, the computational complexity is significantly reduced. Furthermore, replacing the ReLU6 activation function in MobileNetV2 with H-Swish enhances segmentation accuracy without increasing the parameter count. To further amplify high-level semantic features, global pooled features are fed into an attention mechanism network. The experimental results demonstrate that MHC-PSPNet performs exceptionally well on our custom dataset, achieving 97.15% accuracy, 89.21% precision, an F1 score of 94.53%, and an Intersection over Union (IoU) of 83.82%. Compared to the ResNet50 version, parameters are reduced by approximately 18.6 times, while detection accuracy improves, underscoring the efficiency and practicality of the proposed algorithm. Full article
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<p>PSPNet network architecture.</p>
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<p>MHC-PSPNet network architecture.</p>
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<p>Inverted residual structure.</p>
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<p>CBAM attention mechanism.</p>
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<p>Channel attention and spatial attention modules.</p>
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<p>Sigmoid and h-sigmoid function graphs.</p>
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<p>Swish and H-Swish function images.</p>
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<p>Image enhancement result example.</p>
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<p>Examples from the dataset.</p>
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<p>Picture annotation example diagram.</p>
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<p>Variation diagram of loss function.</p>
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<p>Visualization of five types of network segmentation results.</p>
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<p>Segmentation results of the proposed network in four environments.</p>
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18 pages, 2236 KiB  
Article
Flame Combustion State Detection Method of Cement Rotary Furnace Based on Improved RE-DDPM and DAF-FasterNet
by Yizhuo Zhang, Zixuan Gu, Huiling Yu and Shen Shi
Appl. Sci. 2024, 14(22), 10640; https://doi.org/10.3390/app142210640 - 18 Nov 2024
Viewed by 480
Abstract
It is of great significance to effectively identify the flame-burning state of cement rotary kilns to optimize the calcination process and ensure the quality of cement. However, high-temperature and smoke-filled environments bring about difficulties with respect to accurate feature extraction and data acquisition. [...] Read more.
It is of great significance to effectively identify the flame-burning state of cement rotary kilns to optimize the calcination process and ensure the quality of cement. However, high-temperature and smoke-filled environments bring about difficulties with respect to accurate feature extraction and data acquisition. To address these challenges, this paper proposes a novel approach. First, an improved denoising diffusion probability model (RE-DDPM) is proposed. By applying a mask to the burning area and mixing it with the actual image in the denoising process, local diversity generation in the image was realized, and the problem of limited and uneven data was solved. Secondly, this article proposes the DAF-FasterNet model, which incorporates a deformable attention mechanism (DAS) and replaces the ReLU activation function with FReLU so that it can better focus on key flame features and extract finer spatial details. The RE-DDPM method exhibits faster convergence and lower FID scores, indicating that the generated images are more realistic. DAF-FasterNet achieves 98.9% training accuracy, 98.1% test accuracy, and a 22.3 ms delay, making it superior to existing methods in flame state recognition. Full article
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<p>Schematic diagram of DDPM training.</p>
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<p>U-Net network architecture.</p>
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<p>(<b>a</b>) A standard convolution operation; (<b>b</b>) A partial convolution operation.</p>
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<p>FasterNet structure.</p>
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<p>Combustion state detection method for cement rotary kilns.</p>
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<p>RE-DDPM.</p>
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<p>(<b>a</b>) represents ReLu: <math display="inline"><semantics> <mrow> <mi>y</mi> <mo>=</mo> <mo movablelimits="true" form="prefix">max</mo> <mfenced separators="" open="(" close=")"> <mi>x</mi> <mo>,</mo> <mn>0</mn> </mfenced> </mrow> </semantics></math>; (<b>b</b>) represents FReLu: <math display="inline"><semantics> <mrow> <mi>y</mi> <mo>=</mo> <mo movablelimits="true" form="prefix">max</mo> <mfenced separators="" open="(" close=")"> <mi>x</mi> <mo>,</mo> <mi>T</mi> <mo>(</mo> <mi>x</mi> <mo>)</mo> </mfenced> </mrow> </semantics></math>.</p>
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<p>DAS attention mechanism.</p>
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<p>DAF-FasterNet network architecture.</p>
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<p>Cement rotary kiln combustion detection system.</p>
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<p>(<b>a</b>) Under-sintering; (<b>b</b>) normal sintering; (<b>c</b>) over-sintering.</p>
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<p>(<b>a</b>) Score for each model in terms of structural similarity; (<b>b</b>) score for each model in terms of learned perceptual image-patch similarity.</p>
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<p>FID change graph.</p>
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<p>(<b>a</b>) Reference image; (<b>b</b>) image generated by VAE; (<b>c</b>) image generated by GAN; (<b>d</b>) image generated by DDPM; (<b>e</b>) image generated by RE-DDPM. Significant regions are highlighted with red boxes.</p>
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<p>(<b>a</b>) Input image; (<b>b</b>) the addition of a mask to the image; (<b>c</b>) image generated by traditional local redrawing; (<b>d</b>) image generated by our proposed local redrawing method. Significant regions are highlighted with red boxes.</p>
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16 pages, 3285 KiB  
Article
Research on the Classification of Sun-Dried Wild Ginseng Based on an Improved ResNeXt50 Model
by Dongming Li, Zhenkun Zhao, Yingying Yin and Chunxi Zhao
Appl. Sci. 2024, 14(22), 10613; https://doi.org/10.3390/app142210613 - 18 Nov 2024
Viewed by 453
Abstract
Ginseng is a common medicinal herb with high value due to its unique medicinal properties. Traditional methods for classifying ginseng rely heavily on manual judgment, which is time-consuming and subjective. In contrast, deep learning methods can objectively learn the features of ginseng, saving [...] Read more.
Ginseng is a common medicinal herb with high value due to its unique medicinal properties. Traditional methods for classifying ginseng rely heavily on manual judgment, which is time-consuming and subjective. In contrast, deep learning methods can objectively learn the features of ginseng, saving both labor and time. This experiment proposes a ginseng-grade classification model based on an improved ResNeXt50 model. First, each convolutional layer in the Bottleneck structure is replaced with the corresponding Ghost module, reducing the model’s computational complexity and parameter count without compromising performance. Second, the SE attention mechanism is added to the model, allowing it to capture feature information more accurately and precisely. Next, the ELU activation function replaces the original ReLU activation function. Then, the dataset is augmented and divided into four categories for model training. A model suitable for ginseng grade classification was obtained through experimentation. Compared with classic convolutional neural network models ResNet50, AlexNet, iResNet, and EfficientNet_v2_s, the accuracy improved by 10.22%, 5.92%, 4.63%, and 3.4%, respectively. The proposed model achieved the best results, with a validation accuracy of up to 93.14% and a loss value as low as 0.105. Experiments have shown that this method is effective in recognition and can be used for ginseng grade classification research. Full article
(This article belongs to the Special Issue Deep Learning and Digital Image Processing)
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<p>Ginseng dataset. (<b>a</b>) Different levels of ginseng images; (<b>b</b>) sample image after data enhancement.</p>
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<p>Group convolution.</p>
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<p>Ghost module.</p>
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<p>Comparison of the ReLU and Leaky ELU functions.</p>
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<p>Squeeze and excitation networks.</p>
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<p>Improved ResNeXt50 model structure.</p>
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<p>Experimental results of each model: (<b>a</b>) Model Accuracy; (<b>b</b>) Model Loss.</p>
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<p>Comparison of thermal characteristic maps before and after model improvement.</p>
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<p>Confusion matrix before and after model improvement. (<b>a</b>) The confusion matrix of improved model; (<b>b</b>) confusion matrix of ResNeXt50.</p>
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<p>Visualization of misclassified samples.</p>
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17 pages, 3868 KiB  
Article
Research on the Quality Grading Method of Ginseng with Improved DenseNet121 Model
by Jinlong Gu, Zhiyi Li, Lijuan Zhang, Yingying Yin, Yan Lv, Yue Yu and Dongming Li
Electronics 2024, 13(22), 4504; https://doi.org/10.3390/electronics13224504 - 16 Nov 2024
Viewed by 452
Abstract
Ginseng is an important medicinal plant widely used in traditional Chinese medicine. Traditional methods for evaluating the visual quality of ginseng have limitations. This study presents a new method for grading ginseng’s appearance quality using an improved DenseNet121 model. We enhance the network’s [...] Read more.
Ginseng is an important medicinal plant widely used in traditional Chinese medicine. Traditional methods for evaluating the visual quality of ginseng have limitations. This study presents a new method for grading ginseng’s appearance quality using an improved DenseNet121 model. We enhance the network’s capability to recognize various channel features by integrating a CA (Coordinate Attention) mechanism. We also use grouped convolution instead of standard convolution in dense layers to lower the number of model parameters and improve efficiency. Additionally, we substitute the ReLU (Rectified Linear Unit) activation function with the ELU (Exponential Linear Unit) activation function, which reduces the problem of neuron death related to ReLU and increases the number of active neurons. We compared several network models, including DenseNet121, ResNet50, ResNet101, GoogleNet, and InceptionV3, to evaluate their performance against our method. Results showed that the improved DenseNet121 model reached an accuracy of 95.5% on the test set, demonstrating high reliability. This finding provides valuable support for the field of ginseng grading. Full article
(This article belongs to the Special Issue Applications of Artificial Intelligence in Image and Video Processing)
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<p>Ginseng dataset. (<b>a</b>) Original dataset; (<b>b</b>) Dataset after data enhancement.</p>
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<p>Improved Network Model. In the diagram, the symbol * denotes the convolution operation. Specifically, group convolution divides the input channels into several groups, and then performs the convolution operation on each group using distinct convolutional kernels.</p>
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<p>Coordinate Attention Mechanism.</p>
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<p>Schematic diagram of group convolution.</p>
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<p>Activation function comparison chart.</p>
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<p>Visualization results of the thermal characteristic diagram of the new network before and after adding the CA module. (<b>a</b>) Input image; (<b>b</b>) image before adding the CA module; (<b>c</b>) image after adding the CA module.</p>
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<p>Accuracy of different models.</p>
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<p>(<b>a</b>) Loss of different models; (<b>b</b>) The loss between training and validation.</p>
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<p>(<b>a</b>) Original confusion matrix; (<b>b</b>) Improved confusion matrix.</p>
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40 pages, 40760 KiB  
Article
Dynamic-Max-Value ReLU Functions for Adversarially Robust Machine Learning Models
by Korn Sooksatra and Pablo Rivas
Mathematics 2024, 12(22), 3551; https://doi.org/10.3390/math12223551 - 13 Nov 2024
Viewed by 800
Abstract
The proliferation of deep learning has transformed artificial intelligence, demonstrating prowess in domains such as image recognition, natural language processing, and robotics. Nonetheless, deep learning models are susceptible to adversarial examples, well-crafted inputs that can induce erroneous predictions, particularly in safety-critical contexts. Researchers [...] Read more.
The proliferation of deep learning has transformed artificial intelligence, demonstrating prowess in domains such as image recognition, natural language processing, and robotics. Nonetheless, deep learning models are susceptible to adversarial examples, well-crafted inputs that can induce erroneous predictions, particularly in safety-critical contexts. Researchers actively pursue countermeasures such as adversarial training and robust optimization to fortify model resilience. This vulnerability is notably accentuated by the ubiquitous utilization of ReLU functions in deep learning models. A previous study proposed an innovative solution to mitigate this vulnerability, presenting a capped ReLU function tailored to bolster neural network robustness against adversarial examples. However, the approach had a scalability problem. To address this limitation, a series of comprehensive experiments are undertaken across diverse datasets, and we introduce the dynamic-max-value ReLU function to address the scalability problem. Full article
(This article belongs to the Special Issue Advances in Trustworthy and Robust Artificial Intelligence)
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<p>Adversarial example that misleads an image classifier to predict the image as a cat.</p>
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<p>Denoised autoencoder for preprocessing of an adversarial example to create a clean/denoised sample. The solid line is the process with the autoencoder, and the dashed line is the process without the autoencoder.</p>
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<p>Randomized smoothing method, where the most common predictions are picked as the output. In this example, four noises are generated by the noise generator.</p>
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<p>Adversarial example detection technique where the detected samples are thrown away.</p>
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<p>An example of S-ReLU with a max value of 2.</p>
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<p>Examples of the MNIST dataset.</p>
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<p>Examples of the CIFAR10 dataset.</p>
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<p>Examples of the CIFAR100 dataset.</p>
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<p>Examples of the TinyImagenet dataset.</p>
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<p>Architecture of our approach with an added layer (in red) with D-ReLU before the output layer.</p>
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<p>Accuracy of two types of networks on clean MNIST and adversarial examples when adding a dense layer with a D-ReLU function before the output layer.</p>
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<p>Accuracy of several types of networks on clean CIFAR10 and adversarial examples when adding a dense layer with a D-ReLU function before the output layer.</p>
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<p>Accuracy of several types of CNNs on clean CIFAR10 and adversarial examples when adding a convolutional layer with a D-ReLU function after the input layer.</p>
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<p>Accuracy of several types of networks on clean CIFAR100 and adversarial examples when adding a dense layer with a D-ReLU function before the output layer.</p>
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<p>Accuracy of several types of networks on clean TinyImagenet and adversarial examples when adding a dense layer with a D-ReLU function before the output layer.</p>
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<p>Accuracy of several types of networks on clean CIFAR10 and adversarial examples generated by a black-box attack (i.e., square attack) when adding a dense layer with a D-ReLU function before the output layer.</p>
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<p>Accuracy of several types of networks on clean CIFAR100 and adversarial examples generated by a black-box attack (i.e., square attack) when adding a dense layer with a D-ReLU function before the output layer.</p>
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<p>Accuracy of several types of networks on clean TinyImagenet and adversarial examples generated by a black-box attack (i.e., square attack) when adding a dense layer with a D-ReLU function before the output layer.</p>
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<p>Accuracy of several types of networks on clean CIFAR10 and adversarial examples when adding a dense layer with a D-ReLU function before the output layer and training them with augmented data samples generated from the EDM.</p>
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<p>Accuracy of several types of networks on clean CIFAR100 and adversarial examples when adding a dense layer with a D-ReLU function before the output layer and training them with augmented data samples generated from the EDM.</p>
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<p>Accuracy of several types of networks on clean TinyImagenet and adversarial examples when adding a dense layer with a D-ReLU function before the output layer and training them with augmented data samples generated from the EDM.</p>
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<p>Accuracy of several types of networks on clean CIFAR10 and adversarial examples generated by a black-box attack (i.e., square attack) when adding a dense layer with a D-ReLU function before the output layer and training them with augmented data samples generated from the EDM.</p>
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<p>Accuracy of several types of networks on clean CIFAR10 and adversarial examples generated by a black-box attack (i.e., square attack) when adding a dense layer with a D-ReLU function before the output layer and training them with augmented data samples generated from the EDM.</p>
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<p>Accuracy of several types of networks on clean CIFAR100 and adversarial examples generated by a black-box attack (i.e., square attack) when adding a dense layer with a D-ReLU function before the output layer and training them with augmented data samples generated from the EDM.</p>
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<p>Accuracy of several types of networks on clean CIFAR100 and adversarial examples generated by a black-box attack (i.e., square attack) when adding a dense layer with a D-ReLU function before the output layer and training them with augmented data samples generated from the EDM.</p>
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<p>Accuracy of several types of networks on clean TinyImagenet and adversarial examples generated by black-box attacks when adding a dense layer with a D-ReLU function before the output layer and training them with augmented data samples generated from the EDM.</p>
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<p>Accuracy of several types of networks on clean TinyImagenet and adversarial examples generated by black-box attacks when adding a dense layer with a D-ReLU function before the output layer and training them with augmented data samples generated from the EDM.</p>
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<p>Accuracy of several approaches on the CIFAR10 dataset under an APGD_CE attack with various perturbation bounds, where mReLU is D-ReLU.</p>
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<p>Accuracy of several approaches on the CIFAR100 dataset under an APGD_CE attack with various perturbation bounds, where mReLU is D-ReLU.</p>
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<p>Accuracy of several approaches on the TinyImagenet dataset under an APGD_CE attack with various perturbation bounds, where mReLU is D-ReLU.</p>
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14 pages, 12763 KiB  
Article
Semantic Segmentation Model-Based Boundary Line Recognition Method for Wheat Harvesting
by Qian Wang, Wuchang Qin, Mengnan Liu, Junjie Zhao, Qingzhen Zhu and Yanxin Yin
Agriculture 2024, 14(10), 1846; https://doi.org/10.3390/agriculture14101846 - 19 Oct 2024
Viewed by 920
Abstract
The wheat harvesting boundary line is vital reference information for the path tracking of an autonomously driving combine harvester. However, unfavorable factors, such as a complex light environment, tree shade, weeds, and wheat stubble color interference in the field, make it challenging to [...] Read more.
The wheat harvesting boundary line is vital reference information for the path tracking of an autonomously driving combine harvester. However, unfavorable factors, such as a complex light environment, tree shade, weeds, and wheat stubble color interference in the field, make it challenging to identify the wheat harvest boundary line accurately and quickly. Therefore, this paper proposes a harvest boundary line recognition model for wheat harvesting based on the MV3_DeepLabV3+ network framework, which can quickly and accurately complete the identification in complex environments. The model uses the lightweight MobileNetV3_Large as the backbone network and the LeakyReLU activation function to avoid the neural death problem. Depth-separable convolution is introduced into Atrous Spatial Pyramid Pooling (ASPP) to reduce the complexity of network parameters. The cubic B-spline curve-fitting method extracts the wheat harvesting boundary line. A prototype harvester for wheat harvesting boundary recognition was built, and field tests were conducted. The test results show that the wheat harvest boundary line recognition model proposed in this paper achieves a segmentation accuracy of 98.04% for unharvested wheat regions in complex environments, with an IoU of 95.02%. When the combine harvester travels at 0~1.5 m/s, the normal speed for operation, the average processing time and pixel error for a single image are 0.15 s and 7.3 pixels, respectively. This method could achieve high recognition accuracy and fast recognition speed. This paper provides a practical reference for the autonomous harvesting operation of a combine harvester. Full article
(This article belongs to the Special Issue Agricultural Collaborative Robots for Smart Farming)
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<p>MV3-DeepLabV3+ model structure.</p>
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<p>Bneck structure.</p>
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<p>Cubic B-spline sampling algorithm’s boundary-line-fitting results.</p>
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<p>Combine harvester field collection data.</p>
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<p>Cubic B-spline sampling algorithm’s boundary-line-fitting results. Keys: (<b>a</b>) image labeling information, (<b>b</b>) strong light, (<b>c</b>) backlight, (<b>d</b>) shadow occlusion, (<b>e</b>) weak light, (<b>f</b>) front lighting, (<b>g</b>) land edge.</p>
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<p>Comparison of segmentation effects of different semantic segmentation models.</p>
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<p>Fitting boundary lines using cubic B-spline sampling algorithm.</p>
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18 pages, 4823 KiB  
Article
Prediction of PM2.5 Concentration Based on Deep Learning for High-Dimensional Time Series
by Jie Hu, Yuan Jia, Zhen-Hong Jia, Cong-Bing He, Fei Shi and Xiao-Hui Huang
Appl. Sci. 2024, 14(19), 8745; https://doi.org/10.3390/app14198745 - 27 Sep 2024
Cited by 1 | Viewed by 620
Abstract
PM2.5 poses a serious threat to human life and health, so the accurate prediction of PM2.5 concentration is essential for controlling air pollution. However, previous studies lacked the generalization ability to predict high-dimensional PM2.5 concentration time series. Therefore, a new [...] Read more.
PM2.5 poses a serious threat to human life and health, so the accurate prediction of PM2.5 concentration is essential for controlling air pollution. However, previous studies lacked the generalization ability to predict high-dimensional PM2.5 concentration time series. Therefore, a new model for predicting PM2.5 concentration was proposed to address this in this paper. Firstly, the linear rectification function with leakage (LeakyRelu) was used to replace the activation function in the Temporal Convolutional Network (TCN) to better capture the dependence of feature data over long distances. Next, the residual structure, dilated rate, and feature-matching convolution position of the TCN were adjusted to improve the performance of the improved TCN (LR-TCN) and reduce the amount of computation. Finally, a new prediction model (GRU-LR-TCN) was established, which adaptively integrated the prediction of the fused Gated Recurrent Unit (GRU) and LR-TCN based on the inverse ratio of root mean square error (RMSE) weighting. The experimental results show that, for monitoring station #1001, LR-TCN increased the RMSE, mean absolute error (MAE), and determination coefficient (R2) by 12.9%, 11.3%, and 3.8%, respectively, compared with baselines. Compared with LR-TCN, GRU-LR-TCN improved the index symmetric mean absolute percentage error (SMAPE) by 7.1%. In addition, by comparing the estimation results with other models on other air quality datasets, all the indicators have advantages, and it is further demonstrated that the GRU-LR-TCN model exhibits superior generalization across various datasets, proving to be more efficient and applicable in predicting urban PM2.5 concentration. This can contribute to enhancing air quality and safeguarding public health. Full article
(This article belongs to the Section Ecology Science and Engineering)
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<p>The flowchart diagram of the research design.</p>
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<p>L-TCN structure.</p>
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<p>Dilated causal convolution. (<b>a</b>) TCN dilated causal convolution structure; (<b>b</b>) L-TCN dilated causal convolution structure.</p>
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<p>LR-TCN structure.</p>
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<p>Flowchart of the GRU-LR-TCN integrated predicting model.</p>
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<p>Pearson correlation between features related to PM<sub>2.5</sub> in monitoring station 1001.</p>
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<p>Results of PM<sub>2.5</sub> concentration estimation for the next hour: (<b>a</b>) estimated results at monitoring station 1001; (<b>b</b>) estimated results at monitoring station 1002; (<b>c</b>) estimated results at monitoring station 1003; (<b>d</b>) estimated results at monitoring station 1023.</p>
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16 pages, 4056 KiB  
Article
Research on High-Speed Train Bearing Fault Diagnosis Method Based on Domain-Adversarial Transfer Learning
by Yingyong Zou, Wenzhuo Zhao, Tao Liu, Xingkui Zhang and Yaochen Shi
Appl. Sci. 2024, 14(19), 8666; https://doi.org/10.3390/app14198666 - 26 Sep 2024
Viewed by 604
Abstract
Traditional bearing fault diagnosis methods struggle to effectively extract distinctive, domain-invariable characterizations from one-dimensional vibration signals of high-speed train (HST) bearings under variable load conditions. A deep migration fault diagnosis method based on the combination of a domain-adversarial network and signal reconstruction unit [...] Read more.
Traditional bearing fault diagnosis methods struggle to effectively extract distinctive, domain-invariable characterizations from one-dimensional vibration signals of high-speed train (HST) bearings under variable load conditions. A deep migration fault diagnosis method based on the combination of a domain-adversarial network and signal reconstruction unit (CRU) is proposed for this purpose. The feature extraction module, which includes a one-dimensional convolutional (Cov1d) layer, a normalization layer, a ReLU activation function, and a max-pooling layer, is integrated with the CRU to form a feature extractor capable of learning key fault-related features. Additionally, the fault identification module and domain discrimination module utilize a combination of fully connected layers and dropout to reduce model parameters and mitigate the risk of overfitting. It is experimentally validated on two sets of bearing datasets, and the results show that the performance of the proposed method is better than other diagnostic methods under cross-load conditions, and it can be used as an effective cross-load bearing fault diagnosis method. Full article
(This article belongs to the Collection Bearing Fault Detection and Diagnosis)
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<p>Structure of transfer learning fault diagnosis model.</p>
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<p>Structure of feature extractor module.</p>
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<p>Structure of CRU.</p>
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<p>Time-domain and frequency-domain images of each health state of the Skf6205 bearing.</p>
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<p>Visualization of t-SNE for each experimental result.</p>
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<p>Confusion matrix for each experimental result.</p>
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<p>LY-GZ-02 laboratory bench.</p>
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<p>Time-domain and frequency-domain images of four health states of Skf6007 bearings.</p>
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<p>Confusion matrix for each experimental method.</p>
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<p>Confusion matrix for each experimental method.</p>
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10 pages, 6834 KiB  
Article
A Rectified Linear Unit-Based Memristor-Enhanced Morris–Lecar Neuron Model
by Othman Abdullah Almatroud, Viet-Thanh Pham and Karthikeyan Rajagopal
Mathematics 2024, 12(19), 2970; https://doi.org/10.3390/math12192970 - 25 Sep 2024
Viewed by 599
Abstract
This paper introduces a modified Morris–Lecar neuron model that incorporates a memristor with a ReLU-based activation function. The impact of the memristor on the dynamics of the ML neuron model is analyzed using bifurcation diagrams and Lyapunov exponents. The findings reveal chaotic behavior [...] Read more.
This paper introduces a modified Morris–Lecar neuron model that incorporates a memristor with a ReLU-based activation function. The impact of the memristor on the dynamics of the ML neuron model is analyzed using bifurcation diagrams and Lyapunov exponents. The findings reveal chaotic behavior within specific parameter ranges, while increased magnetic strength tends to maintain periodic dynamics. The emergence of various firing patterns, including periodic and chaotic spiking as well as square-wave and triangle-wave bursting is also evident. The modified model also demonstrates multistability across certain parameter ranges. Additionally, the dynamics of a network of these modified models are explored. This study shows that synchronization depends on the strength of the magnetic flux, with synchronization occurring at lower coupling strengths as the magnetic flux increases. The network patterns also reveal the formation of different chimera states, such as traveling and non-stationary chimera states. Full article
(This article belongs to the Special Issue Chaotic Systems and Their Applications, 2nd Edition)
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<p>The bifurcation diagram of the ReLU-based memristor ML model for <math display="inline"><semantics> <mrow> <msub> <mrow> <mi>I</mi> </mrow> <mrow> <mn>0</mn> </mrow> </msub> <mo>=</mo> <mn>0</mn> </mrow> </semantics></math>, according to <math display="inline"><semantics> <mrow> <msub> <mrow> <mi>V</mi> </mrow> <mrow> <mi>K</mi> </mrow> </msub> </mrow> </semantics></math>. The corresponding MLE diagram is shown below the bifurcation diagram. (<b>a</b>) <math display="inline"><semantics> <mrow> <mi>k</mi> <mo>=</mo> <mn>0.5</mn> </mrow> </semantics></math>. (<b>b</b>) <math display="inline"><semantics> <mrow> <mi>k</mi> <mo>=</mo> <mn>3</mn> </mrow> </semantics></math>. (<b>c</b>) <math display="inline"><semantics> <mrow> <mi>k</mi> <mo>=</mo> <mn>5</mn> </mrow> </semantics></math>. (<b>d</b>) <math display="inline"><semantics> <mrow> <mi>k</mi> <mo>=</mo> <mn>8</mn> </mrow> </semantics></math>.</p>
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<p>The bifurcation diagram of the ReLU-based memristor ML model for <math display="inline"><semantics> <mrow> <msub> <mrow> <mi>V</mi> </mrow> <mrow> <mi>k</mi> </mrow> </msub> <mo>=</mo> <mo>−</mo> <mn>220</mn> </mrow> </semantics></math>, according to <math display="inline"><semantics> <mrow> <msub> <mrow> <mi>I</mi> </mrow> <mrow> <mn>0</mn> </mrow> </msub> </mrow> </semantics></math>. The corresponding MLE diagram is shown below the bifurcation diagram. (<b>a</b>) <math display="inline"><semantics> <mrow> <mi>k</mi> <mo>=</mo> <mn>2</mn> </mrow> </semantics></math>. (<b>b</b>) <math display="inline"><semantics> <mrow> <mi>k</mi> <mo>=</mo> <mn>5</mn> </mrow> </semantics></math>.</p>
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<p>The bifurcation diagram of the ReLU-based memristor ML model for <math display="inline"><semantics> <mrow> <msub> <mrow> <mi>V</mi> </mrow> <mrow> <mi>k</mi> </mrow> </msub> <mo>=</mo> <mo>−</mo> <mn>220</mn> </mrow> </semantics></math>, according to <math display="inline"><semantics> <mrow> <mi>k</mi> </mrow> </semantics></math>. The corresponding MLE diagram is shown below the bifurcation diagram. (<b>a</b>) <math display="inline"><semantics> <mrow> <msub> <mrow> <mi>I</mi> </mrow> <mrow> <mn>0</mn> </mrow> </msub> <mo>=</mo> <mn>0</mn> </mrow> </semantics></math>. (<b>b</b>) <math display="inline"><semantics> <mrow> <msub> <mrow> <mi>I</mi> </mrow> <mrow> <mn>0</mn> </mrow> </msub> <mo>=</mo> <mn>0.01</mn> </mrow> </semantics></math>.</p>
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<p>The phase space of the ReLU-based memristor ML model in different parameters of <math display="inline"><semantics> <mrow> <mi>k</mi> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <msub> <mrow> <mi>V</mi> </mrow> <mrow> <mi>K</mi> </mrow> </msub> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <msub> <mrow> <mi>I</mi> </mrow> <mrow> <mn>0</mn> </mrow> </msub> <mo>=</mo> <mn>0</mn> </mrow> </semantics></math>. The time series of each attractor is shown in its subset. (<b>a</b>) <math display="inline"><semantics> <mrow> <mi>k</mi> <mo>=</mo> <mn>0.5</mn> <mo>,</mo> <msub> <mrow> <mo> </mo> <mi>V</mi> </mrow> <mrow> <mi>K</mi> </mrow> </msub> <mo>=</mo> <mo>−</mo> <mn>400</mn> <mo>.</mo> </mrow> </semantics></math> (<b>b</b>) <math display="inline"><semantics> <mrow> <mi>k</mi> <mo>=</mo> <mn>0.5</mn> <mo>,</mo> <msub> <mrow> <mi>V</mi> </mrow> <mrow> <mi>K</mi> </mrow> </msub> <mo>=</mo> <mo>−</mo> <mn>300</mn> </mrow> </semantics></math>. (<b>c</b>) <math display="inline"><semantics> <mrow> <mi>k</mi> <mo>=</mo> <mn>0.5</mn> <mo>,</mo> <msub> <mrow> <mo> </mo> <mi>V</mi> </mrow> <mrow> <mi>K</mi> </mrow> </msub> <mo>=</mo> <mo>−</mo> <mn>220</mn> </mrow> </semantics></math>. (<b>d</b>) <math display="inline"><semantics> <mrow> <mi>k</mi> <mo>=</mo> <mn>0.5</mn> <mo>,</mo> <msub> <mrow> <mo> </mo> <mi>V</mi> </mrow> <mrow> <mi>K</mi> </mrow> </msub> <mo>=</mo> <mo>−</mo> <mn>200</mn> <mo>.</mo> </mrow> </semantics></math> (<b>e</b>) <math display="inline"><semantics> <mrow> <mi>k</mi> <mo>=</mo> <mn>3</mn> <mo>,</mo> <msub> <mrow> <mi>V</mi> </mrow> <mrow> <mi>K</mi> </mrow> </msub> <mo>=</mo> <mo>−</mo> <mn>200</mn> </mrow> </semantics></math>. (<b>f</b>) <math display="inline"><semantics> <mrow> <mi>k</mi> <mo>=</mo> <mn>3</mn> <mo>,</mo> <msub> <mrow> <mi>V</mi> </mrow> <mrow> <mi>K</mi> </mrow> </msub> <mo>=</mo> <mo>−</mo> <mn>220</mn> </mrow> </semantics></math>. (<b>g</b>) <math display="inline"><semantics> <mrow> <mi>k</mi> <mo>=</mo> <mn>5</mn> <mo>,</mo> <msub> <mrow> <mi>V</mi> </mrow> <mrow> <mi>K</mi> </mrow> </msub> <mo>=</mo> <mo>−</mo> <mn>300</mn> <mo>.</mo> </mrow> </semantics></math> (<b>h</b>) <math display="inline"><semantics> <mrow> <mi>k</mi> <mo>=</mo> <mn>5</mn> <mo>,</mo> <msub> <mrow> <mo> </mo> <mi>V</mi> </mrow> <mrow> <mi>K</mi> </mrow> </msub> <mo>=</mo> <mo>−</mo> <mn>220</mn> </mrow> </semantics></math>.</p>
Full article ">Figure 5
<p>Dynamical map of the ReLU-based memristor ML model in two-dimensional planes of <math display="inline"><semantics> <mrow> <mo>(</mo> <msub> <mrow> <mi>V</mi> </mrow> <mrow> <mi>K</mi> </mrow> </msub> <mo>,</mo> <mi>k</mi> <mo>)</mo> </mrow> </semantics></math> in parts (<b>a</b>,<b>b</b>) and <math display="inline"><semantics> <mrow> <mo>(</mo> <msub> <mrow> <mi>I</mi> </mrow> <mrow> <mn>0</mn> </mrow> </msub> <mo>,</mo> <mi>k</mi> <mo>)</mo> </mrow> </semantics></math> in parts (<b>c</b>,<b>d</b>). The period of oscillation is shown in the left column and the maximum Lyapunov exponent is shown in the right column, where the yellow color shows the chaotic region.</p>
Full article ">Figure 6
<p>Multistability emerges in the ReLU-based memristor ML model. (<b>a</b>) The parameters are <math display="inline"><semantics> <mrow> <mi>k</mi> <mo>=</mo> <mn>0.6</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <msub> <mrow> <mi>V</mi> </mrow> <mrow> <mi>K</mi> </mrow> </msub> <mo>=</mo> <mo>−</mo> <mn>220</mn> </mrow> </semantics></math>, and <math display="inline"><semantics> <mrow> <msub> <mrow> <mi>I</mi> </mrow> <mrow> <mn>0</mn> </mrow> </msub> <mo>=</mo> <mn>0</mn> </mrow> </semantics></math> and the initial conditions of the orange and red firings are <math display="inline"><semantics> <mrow> <mo>[</mo> <mo>−</mo> <mn>0.16</mn> <mo>,</mo> <mn>0</mn> <mo>,</mo> <mo>−</mo> <mn>187.11</mn> <mo>]</mo> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <mfenced open="[" close="]" separators="|"> <mrow> <mo>−</mo> <mn>0.19</mn> <mo>,</mo> <mn>0</mn> <mo>,</mo> <mn>2.97</mn> </mrow> </mfenced> </mrow> </semantics></math>, respectively. (<b>b</b>) The parameters are <math display="inline"><semantics> <mrow> <mi>k</mi> <mo>=</mo> <mn>6.5</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <msub> <mrow> <mi>V</mi> </mrow> <mrow> <mi>K</mi> </mrow> </msub> <mo>=</mo> <mo>−</mo> <mn>220</mn> </mrow> </semantics></math>, and <math display="inline"><semantics> <mrow> <msub> <mrow> <mi>I</mi> </mrow> <mrow> <mn>0</mn> </mrow> </msub> <mo>=</mo> <mn>0</mn> </mrow> </semantics></math> and the initial conditions of the orange and red firings are <math display="inline"><semantics> <mrow> <mo>[</mo> <mo>−</mo> <mn>0.22</mn> <mo>,</mo> <mn>0</mn> <mo>,</mo> <mn>4.8</mn> <mo>]</mo> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <mo>[</mo> <mo>−</mo> <mn>0.24</mn> <mo>,</mo> <mn>0</mn> <mo>,</mo> <mn>4.78</mn> <mo>]</mo> </mrow> </semantics></math>, respectively.</p>
Full article ">Figure 7
<p>(<b>a</b>) The synchronization error (<math display="inline"><semantics> <mrow> <mi>E</mi> </mrow> </semantics></math>) of the network of memristive ML neurons (Equation (5)) according to the coupling strength (<math display="inline"><semantics> <mrow> <mi>ϵ</mi> </mrow> </semantics></math>) and the magnetic induction strength (<math display="inline"><semantics> <mrow> <mi>k</mi> </mrow> </semantics></math>). (<b>b</b>) One-dimensional synchronization error according to the coupling strength (<math display="inline"><semantics> <mrow> <mi>ϵ</mi> </mrow> </semantics></math>) for <math display="inline"><semantics> <mrow> <mi>k</mi> <mo>=</mo> <mn>3</mn> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <mn>5</mn> <mo>,</mo> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <mn>8</mn> </mrow> </semantics></math>.</p>
Full article ">Figure 8
<p>Temporal evolution of the network of memristive ML neurons (Equation (5)). (<b>a</b>) For <math display="inline"><semantics> <mrow> <mi>k</mi> <mo>=</mo> <mn>8</mn> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <mi>ϵ</mi> <mo>=</mo> <mn>1.4</mn> </mrow> </semantics></math>, a traveling chimera is formed. (<b>b</b>) For <math display="inline"><semantics> <mrow> <mi>k</mi> <mo>=</mo> <mn>4</mn> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <mi>ϵ</mi> <mo>=</mo> <mn>0.5</mn> </mrow> </semantics></math>, a traveling chimera is formed. (<b>c</b>) For <math display="inline"><semantics> <mrow> <mi>k</mi> <mo>=</mo> <mn>1</mn> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <mi>ϵ</mi> <mo>=</mo> <mn>0.5</mn> </mrow> </semantics></math>, an imperfect traveling chimera is formed. (<b>d</b>) For <math display="inline"><semantics> <mrow> <mi>k</mi> <mo>=</mo> <mn>1</mn> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <mi>ϵ</mi> <mo>=</mo> <mn>1</mn> </mrow> </semantics></math>, a non-stationary chimera is formed.</p>
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