Accuracy
Toward Malicious Clients Detection in Federated Learning
Dou, Zhihao, Wang, Jiaqi, Sun, Wei, Liu, Zhuqing, Fang, Minghong
Federated learning (FL) enables multiple clients to collaboratively train a global machine learning model without sharing their raw data. However, the decentralized nature of FL introduces vulnerabilities, particularly to poisoning attacks, where malicious clients manipulate their local models to disrupt the training process. While Byzantine-robust aggregation rules have been developed to mitigate such attacks, they remain inadequate against more advanced threats. In response, recent advancements have focused on FL detection techniques to identify potentially malicious participants. Unfortunately, these methods often misclassify numerous benign clients as threats or rely on unrealistic assumptions about the server's capabilities. In this paper, we propose a novel algorithm, SafeFL, specifically designed to accurately identify malicious clients in FL. The SafeFL approach involves the server collecting a series of global models to generate a synthetic dataset, which is then used to distinguish between malicious and benign models based on their behavior. Extensive testing demonstrates that SafeFL outperforms existing methods, offering superior efficiency and accuracy in detecting malicious clients.
Heterogeneous networks in drug-target interaction prediction
Molaee, Mohammad, Charkari, Nasrollah Moghadam, Ghaderi, Foad
D rug discovery requires a tremendous amount of time and cost. Computational drug - target interaction prediction, a n important part of this process, can reduce these requirements by narrowing the search space for wet lab experiments. In this survey, we provid e comprehensive details of graph machine learning - based methods in predicting drug - target interaction, as they have shown promising results in this field. These details include the overall framework, main contribution, dataset s, and their source code s . The selected papers were mainly published from 2020 to 2024 . Prior to discussing papers, we briefly introduce the datasets commonly used with these methods and measurements to assess their performance. Finally, future challenges and some crucial areas that need to be explored are discussed.
A Critical Evaluation of Defenses against Prompt Injection Attacks
Jia, Yuqi, Shao, Zedian, Liu, Yupei, Jia, Jinyuan, Song, Dawn, Gong, Neil Zhenqiang
Large Language Models (LLMs) are vulnerable to prompt injection attacks, and several defenses have recently been proposed, often claiming to mitigate these attacks successfully. However, we argue that existing studies lack a principled approach to evaluating these defenses. In this paper, we argue the need to assess defenses across two critical dimensions: (1) effectiveness, measured against both existing and adaptive prompt injection attacks involving diverse target and injected prompts, and (2) general-purpose utility, ensuring that the defense does not compromise the foundational capabilities of the LLM. Our critical evaluation reveals that prior studies have not followed such a comprehensive evaluation methodology. When assessed using this principled approach, we show that existing defenses are not as successful as previously reported. This work provides a foundation for evaluating future defenses and guiding their development. Our code and data are available at: https://github.com/PIEval123/PIEval.
SzCORE as a benchmark: report from the seizure detection challenge at the 2025 AI in Epilepsy and Neurological Disorders Conference
Dan, Jonathan, Shahbazinia, Amirhossein, Kechris, Christodoulos, Atienza, David
Reliable automatic seizure detection from long-term EEG remains a challenge, as current machine learning models often fail to generalize across patients or clinical settings. Manual EEG review remains the clinical standard, underscoring the need for robust models and standardized evaluation. To rigorously assess algorithm performance, we organized a challenge using a private dataset of continuous EEG recordings from 65 subjects (4,360 hours). Expert neurophysiologists annotated the data, providing ground truth for seizure events. Participants were required to detect seizure onset and duration, with evaluation based on event-based metrics, including sensitivity, precision, F1-score, and false positives per day. The SzCORE framework ensured standardized evaluation. The primary ranking criterion was the event-based F1-score, reflecting clinical relevance by balancing sensitivity and false positives. The challenge received 30 submissions from 19 teams, with 28 algorithms evaluated. Results revealed wide variability in performance, with a top F1-score of 43% (sensitivity 37%, precision 45%), highlighting the ongoing difficulty of seizure detection. The challenge also revealed a gap between reported performance and real-world evaluation, emphasizing the importance of rigorous benchmarking. Compared to previous challenges and commercial systems, the best-performing algorithm in this contest showed improved performance. Importantly, the challenge platform now supports continuous benchmarking, enabling reproducible research, integration of new datasets, and clinical evaluation of seizure detection algorithms using a standardized framework.
Generating Realistic Multi-Beat ECG Signals
Pรถhl, Paul, Schlegel, Viktor, Li, Hao, Bharath, Anil
Generating synthetic ECG data has numerous applications in healthcare, from educational purposes to simulating scenarios and forecasting trends. While recent diffusion models excel at generating short ECG segments, they struggle with longer sequences needed for many clinical applications. This paper proposes a novel three-layer synthesis framework for generating realistic long-form ECG signals. We first generate high-fidelity single beats using a diffusion model, then synthesize inter-beat features preserving critical temporal dependencies, and finally assemble beats into coherent long sequences using feature-guided matching. Our comprehensive evaluation demonstrates that the resulting synthetic ECGs maintain both beat-level morphological fidelity and clinically relevant inter-beat relationships. In arrhythmia classification tasks, our long-form synthetic ECGs significantly outperform end-to-end long-form ECG generation using the diffusion model, highlighting their potential for increasing utility for downstream applications. The approach enables generation of unprecedented multi-minute ECG sequences while preserving essential diagnostic characteristics.
Interpretable Multi-Task PINN for Emotion Recognition and EDA Prediction
Understanding and predicting human emotional and physiological states using wearable sensors has critical applications in stress monitoring, mental health assessment, and affective computing. In this study, we present a novel Multi - Task Physics - Informed Neural Network (PINN) that simultaneously performs Electrodermal Activity (EDA) prediction and emotion classification using the publicly available WESAD dataset. Our model integrates psychological self - reports (PANAS and SAM) with a physics - inspired differential formulation of EDA dynamics, enforcing biophysically grounded constraints through a custom loss that balances data - driven learning and physiological interpretability. The architecture supports dual outputs -- regression for EDA and classification for emotional states -- trained under a unified multi - task framework. Evaluated via 5 - fold cross - validation, the proposed method achieves an average EDA RMSE of 0.0362, Pearson correlation (r) of 0.9919, and F1 - score of 94.08%, outperforming both classical baselines (e.g., SVR, XGBoost) and ablated variants such as emotion - only and EDA - only models. Comparative ablation and multi - task experiments show that including both physics constraints and emotion prediction enhances generalization, reduces overfitting, and leads to physiologically consistent outputs. Moreover, the learned physical parameters -- decay rate (ฮฑ), emotion influence weights (ฮฒ), and temporal scaling (ฮณ) -- remain interpretable and stable across folds, confirming the alignment between the model's latent representation and known stress - response theory. This is the first work to introduce a multi - task PINN architecture for wearable affective computing, bridging black - box deep learning and domain knowledge. Our framework lays the groundwork for interpretable, multimodal, and deployable systems in healthcare and human - computer interaction.
Cellwise and Casewise Robust Covariance in High Dimensions
Centofanti, Fabio, Hubert, Mia, Rousseeuw, Peter J.
The sample covariance matrix is a cornerstone of multivariate statistics, but it is highly sensitive to outliers. These can be casewise outliers, such as cases belonging to a different population, or cellwise outliers, which are deviating cells (entries) of the data matrix. Recently some robust covariance estimators have been developed that can handle both types of outliers, but their computation is only feasible up to at most 20 dimensions. To remedy this we propose the cellRCov method, a robust covariance estimator that simultaneously handles casewise outliers, cellwise outliers, and missing data. It relies on a decomposition of the covariance on principal and orthogonal subspaces, leveraging recent work on robust PCA. It also employs a ridge-type regularization to stabilize the estimated covariance matrix. We establish some theoretical properties of cellRCov, including its casewise and cellwise influence functions as well as consistency and asymptotic normality. A simulation study demonstrates the superior performance of cellRCov in contaminated and missing data scenarios. Furthermore, its practical utility is illustrated in a real-world application to anomaly detection. We also construct and illustrate the cellRCCA method for robust and regularized canonical correlation analysis.
Attack-Resilient Image Watermarking Using Stable Diffusion
Watermarking images is critical for tracking image provenance and proving ownership. With the advent of generative models, such as stable diffusion, that can create fake but realistic images, watermarking has become particularly important to make human-created images reliably identifiable. Unfortunately, the very same stable diffusion technology can remove watermarks injected using existing methods.To address this problem, we present ZoDiac, which uses a pre-trained stable diffusion model to inject a watermark into the trainable latent space, resulting in watermarks that can be reliably detected in the latent vector even when attacked. We evaluate ZoDiac on three benchmarks, MS-COCO, DiffusionDB, and WikiArt, and find that ZoDiac is robust against state-of-the-art watermark attacks, with a watermark detection rate above 98% and a false positive rate below 6.4%, outperforming state-of-the-art watermarking methods. We hypothesize that the reciprocating denoising process in diffusion models may inherently enhance the robustness of the watermark when faced with strong attacks and validate the hypothesis.
Time-Reversal Provides Unsupervised Feedback to LLMs
Large Language Models (LLMs) are typically trained to predict in the forward direction of time. However, recent works have shown that prompting these models to look back and critique their own generations can produce useful feedback. Motivated by this, we explore the question of whether LLMs can be empowered to think (predict and score) backwards to provide unsupervised feedback that complements forward LLMs. Towards this, we introduce Time Reversed Language Models (TRLMs), which can score and generate queries when conditioned on responses, effectively functioning in the reverse direction of time. We show empirically (and theoretically in a stylized setting) that time-reversed models can indeed complement forward model predictions when used to score the query given response for re-ranking multiple forward generations.
A Comprehensive Analysis on the Learning Curve in Kernel Ridge Regression
This paper conducts a comprehensive study of the learning curves of kernel ridge regression (KRR) under minimal assumptions.Our contributions are three-fold: 1) we analyze the role of key properties of the kernel, such as its spectral eigen-decay, the characteristics of the eigenfunctions, and the smoothness of the kernel; 2) we demonstrate the validity of the Gaussian Equivalent Property (GEP), which states that the generalization performance of KRR remains the same when the whitened features are replaced by standard Gaussian vectors, thereby shedding light on the success of previous analyzes under the Gaussian Design Assumption; 3) we derive novel bounds that improve over existing bounds across a broad range of setting such as (in)dependent feature vectors and various combinations of eigen-decay rates in the over/underparameterized regimes.