Mixup is a data augmentation technique that enhances model generalization by interpolating between data points using a mixing ratio lambda in the image domain. Recently, the concept of mixup has been adapted to the graph domain through node-centric interpolations. However, these approaches often fail to address the complexity of interconnected relationships, potentially damaging the graph's natural topology and undermining node interactions. Furthermore, current graph mixup methods employ a one-size-fits-all strategy with a randomly sampled lambda for all mixup pairs, ignoring the diverse needs of different pairs. This paper proposes an Adaptive Graph Mixup (AGMixup) framework for semi-supervised node classification. AGMixup introduces a subgraph-centric approach, which treats each subgraph similarly to how images are handled in Euclidean domains, thus facilitating a more natural integration of mixup into graph-based learning. We also propose an adaptive mechanism to tune the mixing ratio lambda for diverse mixup pairs, guided by the contextual similarity and uncertainty of the involved subgraphs. Extensive experiments across seven datasets on semi-supervised node classification benchmarks demonstrate AGMixup's superiority over state-of-the-art graph mixup methods.

Knowledge graph (KG) alignment aims to integrate different KGs through the linkage of equivalent entities across them, enabling more comprehensive knowledge and facilitating information fusion. Existing methods, whether translation-based or GNN-based, typically solve this problem by projecting entities and relations into a low-dimensional embedding space, each demonstrating unique advantages in aligning a pair of KGs. However, few studies consider combining these approaches to model translation semantics of various orders. To fill this gap, we propose KG2HIN, a novel KG encoder, which innovatively views head entities, relations, and tail entities as three types of nodes, thereby transforming KGs into HINs (heterogeneous information networks). KG2HIN can adaptively learn the importance of various orders of translation semantics by seamlessly combining the HGNN aggregator operator with the translation operator in KG embedding methods. Building upon the KG2HIN encoder, we further develop a network to effectively and efficiently align multiple (more than two) KGs concurrently, a much more challenging task than the traditional pair-KG alignment task. Compared with the state-of-the-art baseline, KG2HIN significantly improves the M-Hits@1 (accuracy) score from 10.25% to 73.05% on the DBP4 dataset and from 41.19% to 97.81% on the DWY-3 dataset, while requiring significantly fewer model parameters and less training time.

With the rapid advancements in computer vision, high-resolution remote sensing imagery has become a crucial data source for object detection. Nevertheless, effectively utilizing limited computational resources and reducing the burden on satellite edge devices remains a significant challenge. To effectively reduce model complexity while maintaining its representational capacity, this article proposes a scale-aware pruning framework (SAPF) to enhance remote sensing object detection ability. First, this article classifies the convolutional layers in object detection models into two categories: layers with a single-scale feature representation and layers with a multiscale feature representation. For convolutional layers with single-scale features, we utilize singular value decomposition (SVD) to quantify feature importance and assess filter redundancy to enhance model efficiency. By removing less critical filters, this pruning criteria aims to reduce the model size and computational load without compromising performance. However, convolutional layers with multiscale features are crucial for optimizing feature extraction and balancing information capture across various scales. To address this, this article evaluates the similarity between convolutional layers with different scales to determine the contribution of various scale features in multiscale fusion. Surprisingly, the SAPF can reduce the FLOPs and parameters, as well as ensure the representational ability obviously when the YOLO v5s and Faster-RCNN are adopted to classify the NWPU VHR-10, RSOD, and SIMD datasets. This means we can save the training computation resources for the model. Additionally, SAPF can significantly improve the efficiency of the model in object detection to ensure its real-time performance.

The advancement of Convolutional Neural Networks (CNNs) has enhanced remote sensing scene classification on satellites. However, the increased computational complexity of CNNs will impose a substantial burden on satellite hardware, thereby hindering the practical application. Although various pruning techniques have been developed to reduce the scale of CNNs by assessing the importance of model parameters, these weight-based methods often lead to a degradation in model performance when the original model fails to provide meaningful parameters at under-trained conditions. In this paper, we introduce a novel Layer-interaction Adaptive Pruning (LiAP) method designed to streamline under-trained models. Unlike conventional approaches, LiAP evaluates the importance of neurons based on the distribution of eigenvalues rather than individual parameters. Specifically, this is achieved by projecting the weight matrix of each convolutional layer into the eigenspace, where the eigenvalues are utilized to assess the redundancy of filters. Then each space will be assigned a fined score based on the eigenvalue distribution to provide a robust measure of filter importance. Compared to weight-based pruning methods, LiAP maintains consistent evaluation accuracy between well-trained and under-trained models, as the eigenspace is inherently robust to variations in the weight parameter space. We conducted extensive experiments on VGG-16 and ResNet-50 architectures using datasets such as AID, NWPU-RESISC45, PatternNet, and WHU-RS19 over various data partitions. Notably, our method achieved State-of-the-Art (SOTA) reductions in both FLOPs and parameters for VGG-16 across the aforementioned datasets. These results underscore the efficacy of LiAP in enhancing the efficiency and applicability of CNNs in satellite-based remote sensing tasks.

Nowadays, pruning techniques have drawn attention to convolutional neural networks (CNNs) for reducing the consumption of computation resources. In particular, the Taylor-based method simplifies the evaluation of importance for each filter as the product of the gradient and weight value of the output features, which outperforms other methods in reductions of parameters and floating point operations (FLOPs). However, the Taylor-based method sacrifices too much accuracy when the overall pruning rate is relatively large compared with other pruning algorithms. In this article, we propose a self-adaptive attention factor (SAAF) to improve the performance of the slimmed model when conventional Taylor-based pruning is utilized under higher pruning. Specifically, SAAF can be calculated by leveraging the remaining ratio of filters at the early pruning stage of the Taylor-based method, and then, some pruned filters can be recovered for improving the accuracy of the slimmed model in terms of SAAF. It means that SAAF can protect filters from being overslimmed to eliminate the degeneration of Taylor-based pruning when the pruning rate is large as well as can compress models apparently across various datasets. We test the efficiency of SAAF on VGG-16 and ResNet-50 with CIFAR-10, Tiny-ImageNet, ImageNet-1000, and remote sensing images. Our method outperforms the traditional Taylor-based method obviously in accuracy, and there are only tiny sacrifices in the reduction of parameters and FLOPs, which is better than other pruning methods.

Structured pruning techniques have achieved great compression performance on convolutional neural networks for image classification tasks. However, the majority of existing methods are sensitive with respect to the model parameters, and their pruning results may be unsatisfactory when the original model is trained poorly. That is, they need the original model to be fully trained, to obtain useful weight information. This is time-consuming, and makes the effectiveness of the pruning results dependent on the degree of model optimization. To address the above issue, we propose a novel metric named Average Filter Information Entropy (AFIE). It decomposes the weight matrix of each layer into a low-rank space, and quantifies the filter importance based on the distribution of the normalized eigenvalues. Intuitively, the eigenvalues capture the covariance among filters, and therefore could be a good guide for pruning. Since the distribution of eigenvalues is robust to the updating of parameters, AFIE can yield a stable evaluation for the importance of each filter no matter whether the original model is trained fully. We implement our AFIE-based pruning method for three popular CNN models of AlexNet, VGG-16, and ResNet-50, and test them on three widely-used image datasets MNIST, CIFAR-10, and ImageNet, respectively. The experimental results are encouraging. We surprisingly observe that for our methods, even when the original model is trained with only one epoch, the AFIE score of each filter keeps identical to the results when the model is fully-trained. This fully indicates the effectiveness of the proposed pruning method.

Convolutional neural networks (CNNs) are used comprehensively in the field of the Internet of Things (IoTs), such as mobile phones, surveillance, and satellite. However, the deployment of CNNs is difficult because the structure of hand-designed networks is complicated. Therefore, we propose a sensitiveness-based network pruning framework (SNPF) to reduce the size of original networks to save computation resources. SNPF will evaluate the importance of each convolutional layer by the reconstruction of inference accuracy when we add extra noise to the original model, and then remove filters in terms of the degree of sensitiveness for each layer. Compared with previous weight-norm-based pruning methods, such as “$\mathscr {C}_{1}$-norm,” “BatchNorm-Pruning,” and “Taylor-Pruning,” SNPF is robust to the update of parameters, which can avoid the inconsistency of evaluation for filters if the parameters of the pretrained model are not fully optimized. Namely, SNPF, can prune the network at the early training stage to save computation resources. We test our method on three prevalent models of VGG-16, ResNet-18, ResNet-50 and a customized Conv-4 with 4 convolutional layers. They are then tested on CIFAR-10, CIFAR-100, ImageNet, and MNIST, respectively. Impressively, we observe that even when the VGG-16 is only trained with 50 epochs, we can get the same evaluation of layer importance as the results when the model is fully trained. Additionally, we can also achieve comparable pruning results to previous weight-oriented methods on the other three models.

Pruning techniques have been utilized widely for convolutional neural networks (CNNs) to reduce the computation resources in remote sensing scene image classification. However, conventional pruning techniques are weight-based, which can not balance the pruning ratio and representation ability appropriately. In this paper, we propose a Data Customization-based Multiobjective Optimization Pruning (DCMOP) framework for the pruning in remote sensing scene image classification, which can not only trade-off between pruning ratio and capability for CNNs, but also speed up the evolutionary process for the pruning. We adopt the multiobjective evolutionary algorithms (MOEAs) to search for a trade-off between the pruning ratio and capability for CNNs. However, a big concern of pruning for networks via MOEAs is that the evaluation of sub-networks is time-costing. This originates that the slimmed sub-networks require a lot of retraining operation, which will burden the hardware. In order to alleviate this limitation, we design a Data Customization-based Proxy Mechanism (DCPM) to reduce the size of the input dataset in terms of the structure of the slimmed sub-network to accelerate significantly the evolutionary process for the pruning. According to this, our proposed DCMOP achieves the pruning with higher efficiency and performance by cooperating with MOEAs and DCPM. Experimental results based on four datasets of AID, NWPURESISC45, PatternNet, and WHU-RS19 show that the proposed DCMOP can achieve a balance between model performance and pruning rate, while obviously reducing the time cost of the pruning.

Convolutional neural networks (CNNs) have been adopted to classify the remote sensing scene image. However, the application of these complicated networks on the satellite platform is difficult because of the limited computation resources. Therefore, we propose an energy-based filter pruning framework (EFPF) to reduce the size of the original model. The energy can be obtained through the eigenvalues of each weight tensor by singular value decomposition (SVD). Specifically, we calculate the energy of each layer by the ratio of eigenvalues that are lower than a specified truncation parameter and then remove filters from the original layer in light of the degree of energy. The EFPF is reliable because SVD techniques can capture the covariance among all filters from the original weight tensor, and therefore, the energy from the eigenvalues can reflect the redundancy of the filters. (i.e., if the distribution of eigenvalues is sharp, then the energy among filters will be lower, and the redundancy will be higher.) Surprisingly, the EFPF can reduce the FLOPs and parameters, as well as improve the top1 accuracy obviously when the VGG-16 and ResNet-50 are adopted to classify the AID, NWPU45, PatternNet, and WHU19 datasets. Additionally, the EFPF can achieve similar pruning results when the original model is fully-trained (converge) and under-trained (In-converge), which means we can save the training computation resources for the original model.