Decentralized cooperative multi-agent multi-armed bandits (DeCMA2B) considers how multiple agents collaborate in a decentralized multi-armed bandit setting. Though this problem has been extensively studied in previous work, most existing methods remain susceptible to various adversarial attacks. In this paper, we first study DeCMA2B with adversarial corruption, where an adversary can corrupt reward observations of all agents with a limited corruption budget. We propose a robust algorithm, called DeMABAR, which ensures that each agent’s individual regret suffers only an additive term proportional to the corruption budget. Then we consider a more realistic scenario where the adversary can only attack a small number of agents. Our theoretical analysis shows that the DeMABAR algorithm can also almost completely eliminate the influence of adversarial attacks and is inherently robust in the Byzantine setting, where an unknown fraction of the agents can be Byzantine, i.e., may arbitrarily select arms and communicate wrong information. We also conduct numerical experiments to illustrate the robustness and effectiveness of the proposed method.

In the realm of complex industrial fault diagnosis, convolutional neural network (CNN) have been widely adopted owing to their powerful feature extraction capabilities. Nevertheless, conventional two-dimensional CNN architectures often struggle to effectively capture temporal characteristics when processing grayscale images converted from time-series signals. To address this limitation, this study proposes a dual-branch network architecture that integrates one-dimensional and two-dimensional convolutional operations. Specifically, the 1D CNN branch extracts temporal features directly from raw vibration signals, while the 2D CNN branch processes grayscale images obtained through time-frequency transformation, thereby enabling a synergistic extraction of temporal and spatial representations. Moreover, to overcome the inherent limitations of traditional cascade forest approaches, we introduce a multi-classifier cascade framework based on XGBoost. By incorporating two XGBoost classifiers, the framework enhances both classification accuracy and model robustness. Empirical results indicate that the proposed model consistently achieves higher diagnostic accuracy and superior generalization performance across multiple fault datasets, particularly in bearing fault diagnosis tasks, rendering it highly suitable for deployment in complex industrial environments.

We investigate various stochastic bandit problems in the presence of adversarial corruptions. A seminal work for this problem is the BARBAR~\cite{gupta2019better} algorithm, which achieves both robustness and efficiency. However, it suffers from a regret of $O(KC)$, which does not match the lower bound of $\Omega(C)$, where $K$ denotes the number of arms and $C$ denotes the corruption level. In this paper, we first improve the BARBAR algorithm by proposing a novel framework called BARBAT, which eliminates the factor of $K$ to achieve an optimal regret bound up to a logarithmic factor. We also extend BARBAT to various settings, including multi-agent bandits, graph bandits, combinatorial semi-bandits and batched bandits. Compared with the Follow-the-Regularized-Leader framework, our methods are more amenable to parallelization, making them suitable for multi-agent and batched bandit settings, and they incur lower computational costs, particularly in semi-bandit problems. Numerical experiments verify the efficiency of the proposed methods.

MOTIVATION: Flow cytometry and mass cytometry are widely used to diagnose diseases and to predict clinical outcomes. When associating clinical features with cytometry data, traditional analysis methods require cell gating as an intermediate step, leading to information loss and susceptibility to batch effects. Here, we wish to explore an alternative approach that predicts clinical features from cytometry data without the cell-gating step. We also wish to test if such a gating-free approach increases the accuracy and robustness of the prediction. RESULTS: We propose a novel strategy (CytoDx) to predict clinical outcomes using cytometry data without cell gating. Applying CytoDx on real-world datasets allow us to predict multiple types of clinical features. In particular, CytoDx is able to predict the response to influenza vaccine using highly heterogeneous datasets, demonstrating that it is not only accurate but also robust to batch effects and cytometry platforms. AVAILABILITY AND IMPLEMENTATION: CytoDx is available as an R package on Bioconductor (bioconductor.org/packages/CytoDx). Data and scripts for reproducing the results are available on bitbucket.org/zichenghu_ucsf/cytodx_study_code/downloads. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.