The existing deep learning-based methods for source code vulnerability detection often suffer from severe loss of syntax and semantics in target code, and neural network models allocating weights to the graph nodes (edges) in target code unreasonably. To address these issues, a method named VulATGCN for detecting source code vulnerabilities was proposed on the basis of Code Property Graph (CPG) and Adaptive Transformer-Graph Convolutional Network (AT-GCN). In the method, CPG was used to represent source code, CodeBERT was combined for node vectorization, and graph centrality analysis was employed to extract deep structural features, thereby capturing the code’s syntax and semantic information in multi-dimensional way. After that, AT-GCN model was designed by integrating strengths of Transformer-based self-attention mechanism, which excels at capturing long-range dependencies, and Graph Convolutional Network (GCN), which is proficient at capturing local features, thereby realizing fusion learning and precise extraction of features from regions with different importance. Experimental results on real vulnerability datasets Big-Vul and SARD show that the proposed method VulATGCN achieves an average F1 score of 82.9%, which is 10.4% to 132.9% higher than deep learning-based vulnerability detection methods such as VulSniper, VulMPFF, and MGVD, with an average increase of approximately 52.9%.
Concerning the problem that the linear eigentransformation method cannot capture the statistical properties of the nonlinear facial image, a Data-driven Local Eigentransformation (DLE) method for face hallucination was proposed. Firstly, some samples most similar to the input image patch were searched. Secondly, a patch-based eigentransformation method was used for modeling the relationship between the Low-Resolution (LR) and High-Resolution (HR) training samples. Finally, a post-processing approach refined the hallucinated results. The experimental results show the proposed method has better visual performance as well as 1.81dB promotion over method of locality-constrained representation in objective evaluation criterion for face image especially with noise. This method can effectively hallucinate surveillant facial images.
Automatic analysis system of Chinese character structure applies many mature techniques in the fields such as computer vision, image understanding to analyze and recognize the Chinese character. GB2312-80 Chinese characters set was chosen to generate subcomponent images. Then the feature description of Chinese characters component structures is generated, and valid ratio is over 90%.