Direct-to-cell satellites enable global network services for our regular phones/IoTs via 4G, 5G, and beyond. To enforce highly available, trustworthy, and roaming policy-compliant network services, they heavily rely on user geolocation and timing information from external global navigation satellite systems (GNSS) to assist with their radio access, authentication, and authorization. Our analysis and field tests reveal that, this cross-technology over-reliance propagates satellite navigation's defects to direct-to-cell satellite networks, leading to diverse issues such as intermittent connectivity, over/under-billing, unauthorized services, and service denials even when direct-to-cell satellites are accessible. Our solution, SN2, adopts the "fate-sharing" principle to reuse direct-to-cell satellites themselves for self-navigating networks. By exploiting the flexible tradeoffs between satellite network availability and navigation accuracy, it enables "good enough" built-in navigation for highly available and functionally correct network services at a negligible cost of hardware or communication resources. Our evaluations with commodity satellite phones and 3GPP NTN protocol stacks demonstrate SN2's 4.4–23.5× network availability boost and 1.9–12.3× access latency reduction over legacy solutions.

The absorption and scattering of light in the water medium naturally impair the quality of underwater images, leading to multiple degradation effects including color casts, reduced visibility, and blurriness. Underwater Image Enhancement (UIE) techniques strive to mitigate these issues, yet the efficacy of different UIE algorithms remains highly variable. This variability underscores the necessity for an objective quality metric capable of precisely assessing the visual quality of underwater images. Traditional quality metrics, which primarily rely on a single score to depict the overall quality level, are insufficiently comprehensive to describe the complex degradation characteristics intrinsic to underwater environments and the multi-dimensional nature of underwater image quality. To address this issue, we construct the first UIE quality evaluation dataset with multi-dimensional quality annotations, broadening the subjective labels from a single overall quality score to multiple specific degradation-related scores. The dataset is known as an enhanced version of our previous Subjectively Annotated UIE Benchmark Dataset (SAUD) and is called SAUD2.0 hereinafter. Based on the SAUD2.0 dataset, we also introduce a Multi-stream COllaborative LEarning network (MCOLE) tailored for quality evaluation of enhanced underwater images. MCOLE capitalizes on the multi-dimensional quality annotations within SAUD2.0, facilitating the training of three specialized networks focused on extracting distinct sets of features: color, visibility, and semantic. These extracted features are then interacted and cohesively merged for quality prediction. Comprehensive experiments conducted on two benchmark datasets reveal that the proposed MCOLE outperforms current underwater image quality metrics. These results clearly validate the efficacy of exploring the multi-dimensional nature of underwater image quality and integrating such multi-dimensional quality annotations into underwater image quality evaluation. Our dataset and code are available athttps://github.com/0117Tzx/MCOLE.

In recent years, the number of malware on the Android platform has been increasing, and with the widespread use of code obfuscation technology, the accuracy of antivirus software and traditional detection algorithms is low. Current state-of-the-art research shows that researchers started applying deep learning methods for malware detection. We proposed an Android malware detection algorithm based on a hybrid deep learning model which combines deep belief network (DBN) and gate recurrent unit (GRU). First of all, analyze the Android malware; in addition to extracting static features, dynamic behavioral features with strong antiobfuscation ability are also extracted. Then, build a hybrid deep learning model for Android malware detection. Because the static features are relatively independent, the DBN is used to process the static features. Because the dynamic features have temporal correlation, the GRU is used to process the dynamic feature sequence. Finally, the training results of DBN and GRU are input into the BP neural network, and the final classification results are output. Experimental results show that, compared with the traditional machine learning algorithms, the Android malware detection model based on hybrid deep learning algorithms has a higher detection accuracy, and it also has a better detection effect on obfuscated malware.