Due to the deep coupling of cyber systems and physical systems in model poewr systems, cybersecurity risks are becoming more prominent in industrial control systems. Cybersecurity issues can make frequency control systems affect the safety of the physical power grid, and detection and mitigation can ensure frequency stability after cyberattacks. However, the parameters of LFC systems are usually uncertain in the real world. the In this paper, we propose a watermark-based cyber-resilient framework for real LFC systems with parameter uncertainty by introducing a parameter identification algorithm, and construct an online application. We validate the proposed framework in a real three-area power system simulation. The results show that the proposed algorithm locates and mitigates cyberattacks in time after they occur and avoids frequency anomalies.
In this article, the safety problem in the integrated energy system is solved using the game theory method. Combined with the characteristics of integrated energy system with multiple time scales and coupled energy flows, a three-stage multi-subject game model containing 0–1 variables is established, and for the definition and analysis of system safety, N-1 failures are considered, and the concept of dynamic safety domain is adopted to measure system safety. Appropriate simplifications were made for the model and it was transformed into a two-stage dynamic game model with incomplete information. Concepts such as N-1 safety criterion and safety margin are used to define the payoffs of both sides of the game, and the game equilibrium is solved to provide support for system safety prevention.
Pure point-based neural networks have recently shown tremendous promise for point cloud tasks, including 3D object classification, 3D object part segmentation, 3D semantic segmentation, and 3D object detection. Nevertheless, it is a laborious process to construct a network for each task due to the artificial parameters and hyperparameters involved, e.g., the depths and widths of the network and the number of sampled points at each stage. In this work, we propose Auto-Points, a novel one-shot search framework that automatically seeks the optimal architecture configuration for point cloud tasks. Technically, we introduce a set abstraction mixer (SAM) layer that is capable of scaling up flexibly along the depth and width of the network. Each SAM layer consists of numerous child candidates, which simplifies architecture search and enables us to discover the optimum design for each point cloud task pursuant to resource constraint from an enormous search space. To fully optimize the child candidates, we develop a weight-entwinement neural architecture search (NAS) technique that entwines the weights of different candidates in the same layer during supernet training such that all candidates can be extremely optimized. Benefiting from the proposed techniques, the trained supernet allows the searched subnets to be exceptionally well-optimized without further retraining or finetuning. In particular, the searched models deliver superior performances on multiple extensively employed benchmarks, 93.9% overall accuracy (OA) on ModelNet40, 89.1% OA on ScanObjectNN, 87.1% instance average IoU on ShapeNetPart, 69.1% mIoU on S3DIS, 70.4% mAP@0.25 on ScanNet V2, and 64.4% mAP@0.25 on SUN RGB-D.
This study introduces a novel approach, Local Spatial Projection Convolution (LSPConv), for point cloud classification and semantic segmentation. Unlike conventional methods utilizing relative coordinates for local geometric information, our motivation stems from the inadequacy of existing techniques for representing the intricate spatial organization of unconsolidated and irregular 3D point clouds. To address this limitation, we propose a Local Spatial Projection Module utilizing a vector projection strategy, designed to capture comprehensive local spatial information more effectively. Moreover, recent studies emphasize the importance of anisotropic kernels for point cloud feature extraction, considering the distinct contributions of individual neighboring points. To cater to this requirement, we introduce the Feature Weight Assignment (FWA) Module to assign weights to neighboring points, enhancing the anisotropy crucial for accurate feature extraction. Additionally, we introduce an Anisotropic Relative Feature Encoding Module that adaptively encodes points based on their relative features, further amplifying the anisotropic characteristics. Our approaches achieve remarkable results for point cloud classification and segmentation in several benchmark datasets based on extensive qualitative and quantitative evaluation.
In this work, we introduce FARP-Net, an adaptive local-global feature aggregation and relation-aware proposal network for high-quality 3D object detection from pure point clouds. Our key insight is that learning adaptive local-global feature aggregation from an irregular yet sparse point cloud and generating superb proposals are both pivotal for detection. Technically, we propose a novel local-global feature aggregation layer (LGFAL) that fully exploits the complementary correlation between local features and global features, and fuses their strengths adaptively via an attention-based fusion module. Furthermore, we incorporate a lightweight feature affine module (LFAM) into LGFAL to map the local features into a normal distribution, thus acquiring fine-grained features of each local region in a weight-sharing manner. During object proposal generation, we propose a weighted relation-aware proposal module (WRPM) that uses an objectness-aware formalism to weigh the relation importance among object candidates for a clear and principal context, thereby facilitating the generation of high-quality proposals. The WRPM challenges the traditional practice of extracting contextual information among all object candidates, which is inefficient as object candidates are always noisy and redundant. Experimentally, FARP-Net delivers superior performance on two widely used benchmarks with fewer parameters, 64.0% mAP@0.25 on the SUN RGB-D dataset and 70.9% mAP@0.25 on the ScanNet V2 dataset. We further validate that the proposed LGFAL and WRPM can be integrated into both indoor and outdoor detectors to boost performance.
Safety assessment is of great significance in the development and promotion of integrated energy system. In order to make the traditional safety assessment can be better applied to large-scale systems, this paper optimizes the safety assessment process from the aspects of the generation of expected fault sets and the solution of multi-energy flow power flow. Implement improvements to the security assessment process.
The 3D object detection is becoming indispensable for environmental perception in autonomous driving. Light detection and ranging (LiDAR) point clouds often fail to distinguish objects with similar structures and are quite sparse for distant or small objects, thereby introducing false and missed detections. To address these issues, LiDAR is often fused with cameras due to the rich textural information provided by images. However, current fusion methods suffer the inefficient data representation and inaccurate alignment of heterogeneous features, leading to poor precision and low efficiency. To this end, we propose a plug-and-play module termed range-image fusion (RI-Fusion) to achieve an effective fusion of LiDAR and camera data, designed to be easily accessible by existing mainstream LiDAR-based algorithms. In this process, we design an image and point cloud alignment method by converting a point cloud into a compact range-view representation through a spherical coordinate transformation. The range image is then integrated with a corresponding camera image utilizing an attention mechanism. The original range image is then concatenated with fusion features to retain point cloud information, and the results are projected onto a spatial point cloud. Finally, the feature-enhanced point cloud can be input into a LiDAR-based 3D object detector. The results of validation experiments involving the KITTI 3D object detection benchmark showed that our proposed fusion method significantly enhanced multiple mainstream LiDAR-based 3D object detectors, PointPillars, SECOND, and Part $\text{A}{^{2}}$ , improving the 3D mAP (mean Average Precision) by 3.61%, 2.98%, and 1.27%, respectively, particularly for small objects such as pedestrians and cyclists.
Recently, point-based networks have exhibited extraordinary potential for 3D point cloud processing. However, owing to the meticulous design of both parameters and hyperparameters inside the network, constructing a promising network for each point cloud task can be an expensive endeavor. In this work, we develop a novel one-shot search framework called Point-NAS to automatically determine optimum architectures for various point cloud tasks. Specifically, we design an elastic feature extraction (EFE) module that serves as a basic unit for architecture search, which expands seamlessly alongside both the width and depth of the network for efficient feature extraction. Based on the EFE module, we devise a searching space, which is encoded into a supernet to provide a wide number of latent network structures for a particular point cloud task. To fully optimize the weights of the supernet, we propose a weight coupling sandwich rule that samples the largest, smallest, and multiple medium models at each iteration and fuses their gradients to update the supernet. Furthermore, we present a united gradient adjustment algorithm that mitigates gradient conflict induced by distinct gradient directions of sampled models and supernet, thus expediting the convergence of the supernet and assuring that it can be comprehensively trained. Pursuant to the provided techniques, the trained supernet enables a multitude of subnets to be incredibly well-optimized. Finally, we conduct an evolutionary search for the supernet under resource constraints to find promising architectures for different tasks. Experimentally, the searched Point-NAS with weights inherited from the supernet realizes outstanding results across a variety of benchmarks. i.e., 94.2% and 88.9% overall accuracy under ModelNet40 and ScanObjectNN, 68.6% mIoU under S3DIS, 63.6% and 69.3% mAP@0.25 under SUN RGB-D and ScanNet V2 datasets.
In an integrated energy system, due to the characteristics of multi-energy flow in the system, it brings inconvenience to the overall analysis, and the characteristics of multi-system coupling allow some faults to propagate between different systems. The topology of the network results in the existence of some key nodes in the system. For the analysis of the network structure, the weak points that affect the security of the system can be found, which can provide guidance and supplements for subsequent security assessments.