Search Results (2)

Loop closure detection is essential for improving the long-term consistency and robustness of simultaneous localization and mapping (SLAM) systems. Existing LiDAR-based loop closure approaches often rely on limited or partial geometric features, restricting their performance in complex environments. To address these limitations, this paper introduces a Density Triangle Descriptor (DTD). The proposed method first extracts keypoints from density images generated from LiDAR point clouds, and then constructs a triangle-based global descriptor that is invariant to rotation and translation, enabling robust structural representation. Furthermore, to enhance local discriminative ability, the neighborhood around each keypoint is modeled as a Gaussian distribution, and a local descriptor is derived from the entropy of its probability distribution. During loop closure detection, candidate matches are first retrieved via hash indexing of triangle edge lengths, followed by entropy-based local verification, and are finally refined by singular value decomposition for accurate pose estimation. Extensive experiments on multiple public datasets demonstrate that compared to STD, the proposed DTD improves the average F1 max score and EP by 18.30% and 20.08%, respectively, while achieving a 50.57% improvement in computational efficiency. Moreover, DTD generalizes well to solid-state LiDAR with non-repetitive scanning patterns, validating its robustness and applicability in complex environments. Full article

This study proposes a lightweight classification framework for anomaly traffic detection in edge computing environments. Thirteen packet- and flow-level features extracted from the CIC-IDS2017 dataset were compressed into 4-dimensional latent vectors using a Sparse Autoencoder (SAE). Two classifiers were compared under the same pipeline: a Feed-Forward network (SAE-FF) and a Deep Neural Network (SAE-DNN). To ensure generalization, all experiments were conducted with 5-fold cross-validation. Performance evaluation revealed that SAE-DNN achieved superior classification performance, with an average accuracy of 99.33% and an AUC of 0.9993. The SAE-FF model, although exhibiting lower performance (average accuracy of 93.66% and AUC of 0.9758), maintained stable outcomes and offered significantly lower computational complexity (~40 FLOPs) compared with SAE-DNN (~8960 FLOPs). Device-level analysis confirmed that SAE-FF was the most efficient option for resource-constrained platforms such as Raspberry Pi 4, whereas SAE-DNN achieved real-time inference capability on the Coral Dev Board by leveraging Edge TPU acceleration. To quantify this trade-off between accuracy and efficiency, we introduce the Edge Performance Efficiency Score (EPES), a composite metric that integrates accuracy, latency, memory usage, FLOPs, and CPU performance into a single score. The proposed EPES provides a practical and comprehensive benchmark for balancing accuracy and efficiency and supporting device-specific model selection in practical edge deployments. These findings highlight the importance of system-aware evaluation and demonstrate that EPES can serve as a valuable guideline for efficient anomaly traffic classification in resource-limited environments. Full article