In X-ray computed tomography, radiation doses are harmful but can be significantly reduced by intuitively decreasing the number of projections. However, less projection views usually lead to low resolution images. To address this issue, we propose a robust and enhanced mechanism on the basis of denoising autoencoding prior, or REDAEP for sparse-view CT reconstruction. REDAEP can substantially improve the reconstruction quality with two novel contributions. First, by employing the variable augmentation technique, REDAEP learns higher-dimensional network with three-channel image and proceeds to the single-channel image reconstruction. Second, REDAEP replaces the 2 L regression loss function with a more robust Lp(0<p<2) regression to preserve more texture details. Empirical results demonstrate that REDAEP can achieve better performance than state-of-the-arts, in terms of quantitative measures and subjective visual quality.

Industrial control system (ICS) employs complex multistate protocols to realize high-reliability communication and intelligent control over automation equipment. ICS has been widely used in various embedded fields, such as autonomous vehicle systems, power automation systems, etc. However, in recent years, many attacks have been performed on ICS, especially its protocols, such as the hijacks over Jeep Uconnect and Tesla Autopilot autonomous systems, also the Stuxnet and DragonFly viruses over national infrastructures. It is important to guarantee the security of ICS protocols. In this article, we present Charon , an efficient fuzzing platform for the vulnerability detection of ICS protocol implementations. In Charon , we propose an innovative fuzzing strategy that leverages state guidance to maximize cross-state code coverage instead of focusing on isolated states during the fuzzing of ICS protocols. Moreover, we devise a novel feedback collection method that employs program status inferring to avoid the restart of the ICS protocol at each iteration, allowing for continuous fuzzing. We evaluate Charon on several popular ICS protocol implementations, including real-time publish subscribe, IEC61850-MMS, MQTT, etc. Compared with typical fuzzers, such as American fuzzy lop, Polar, AFLNET, Boofuzz, and Peach, it averagely improves branch coverage by 234.2%, 194.4%, 215.9%, 52.58%, and 35.18%, respectively. Moreover, it has already confirmed 21 previously unknown vulnerabilities (e.g., stack buffer overflow) among these ICS protocols, most of which are security critical and corresponding patches from vendors have been released accordingly.

Unsupervised deep learning has recently demonstrated the promise to produce high-quality samples. While it has tremendous potential to promote the image colorization task, the performance is limited owing to the high-dimension of data manifold and model capability. This study presents a novel scheme that exploiting the score-based generative model in wavelet domain to address the issue. By taking advantage of the multi-scale and multi-channel representation via wavelet transform, the proposed model learns the priors from stacked wavelet coefficient components, thus learns the image characteristics under coarse and detail frequency spectrums jointly and effectively. Moreover, such a highly flexible generative model without adversarial optimization can execute colorization tasks better under dual consistency terms in wavelet domain, namely data-consistency and structure-consistency. Specifically, in the training phase, a set of multi-channel tensors consisting of wavelet coefficients are used as the input to train the network by denoising score matching. In the test phase, samples are iteratively generated via annealed Langevin dynamics with data and structure consistencies. Experiments demonstrated remarkable improvements of the proposed model on colorization quality, particularly on colorization robustness and diversity.

Embedded operating systems (Embedded OSs) are extensively deployed in many mission-critical industrial scenarios. Any defects within these systems may result in unacceptable losses. Therefore, it is imperative to develop tools to detect bugs within Embedded OSs, thus minimizing potential impacts on industrial infrastructures. Coverage-guided fuzzing is a vulnerability detection technique that has found numerous real-world vulnerabilities within both application programs as well as kernels. However, state-of-the-art kernel fuzzers, e.g., Syzkaller, mainly target general purpose-operating systems, such as Linux, macOS, and Windows, whereas Embedded OSs support is mostly lacking. In this article, we propose Tardis, the first Embedded OSs fuzzer capable of testing a wide selection of Embedded OSs while leveraging coverage feedback. Tardis conducts OS-agnostic code coverage collection and analysis, allowing developers and testers to test a wide range of Embedded OSs without significant manual efforts. We implemented and evaluated Tardis on several well-known Embedded OSs, such as UC/OS and FreeRTOS. Tardis can successfully perform fuzz testing on these kernels without significant manual effort for adaptation. By leveraging coverage feedback, Tardis can cover 51.32% more branches than black-box fuzzing on average on the respective Embedded OSs over 24 h. Tardis also found 17 previously unknown bugs among the target Embedded OSs.

Graph Neural Networks (GNNs) have been increasingly adopted for graph analysis in web applications such as social networks. Yet, efficient GNN serving remains a critical challenge due to high workload fluctuations and intricate GNN operations. Serverless computing, thanks to its flexibility and agility, offers on-demand serving of GNN inference requests. Alas, the request-centric serverless model is still too coarse-grained to avoid resource waste. Observing the significant data locality in computation graphs of requests, we propose λGrapher, a serverless system for GNN serving that achieves resource efficiency through graph sharing and fine-grained resource allocation. "Grapher features the following designs: (1) adaptive timeout for request buffering to balance resource efficiency and inference latency, (2) graph-centric scheduling to minimize computation and memory redundancy, and (3) resource-centric function management with fine-grained resource allocation catered to the resource sensitivities of GNN operations and function orchestration optimized to hide communication latency. We implement a prototype of λGrapher based on the representative open-source serverless platform Knative and evaluate it with real-world traces from various web applications. Our results show that λGrapher can achieve an average savings of 61.5% in memory resource and 47.2% in computing resource compared with the state of the arts while ensuring GNN inference latency.