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FLUX: Efficient Descriptor-Driven Clustered Federated Learning under Arbitrary Distribution Shifts
Fenoglio, Dario, Li, Mohan, Barbiero, Pietro, Lane, Nicholas D., Langheinrich, Marc, Gjoreski, Martin
Federated Learning (FL) enables collaborative model training across multiple clients while preserving data privacy. Traditional FL methods often use a global model to fit all clients, assuming that clients' data are independent and identically distributed (IID). However, when this assumption does not hold, the global model accuracy may drop significantly, limiting FL applicability in real-world scenarios. To address this gap, we propose FLUX, a novel clustering-based FL (CFL) framework that addresses the four most common types of distribution shifts during both training and test time. To this end, FLUX leverages privacy-preserving client-side descriptor extraction and unsupervised clustering to ensure robust performance and scalability across varying levels and types of distribution shifts. Unlike existing CFL methods addressing non-IID client distribution shifts, FLUX i) does not require any prior knowledge of the types of distribution shifts or the number of client clusters, and ii) supports test-time adaptation, enabling unseen and unlabeled clients to benefit from the most suitable cluster-specific models. Extensive experiments across four standard benchmarks, two real-world datasets and ten state-of-the-art baselines show that FLUX improves performance and stability under diverse distribution shifts, achieving an average accuracy gain of up to 23 percentage points over the best-performing baselines, while maintaining computational and communication overhead comparable to FedAvg.
When AI Bends Metal: AI-Assisted Optimization of Design Parameters in Sheet Metal Forming
Tarraf, Ahmad, Kassem-Manthey, Koutaiba, Mohammadi, Seyed Ali, Martin, Philipp, Moj, Lukas, Burak, Semih, Park, Enju, Terboven, Christian, Wolf, Felix
Numerical simulations have revolutionized the industrial design process by reducing prototyping costs, design iterations, and enabling product engineers to explore the design space more efficiently. However, the growing scale of simulations demands substantial expert knowledge, computational resources, and time. A key challenge is identifying input parameters that yield optimal results, as iterative simulations are costly and can have a large environmental impact. This paper presents an AI-assisted workflow that reduces expert involvement in parameter optimization through the use of Bayesian optimization. Furthermore, we present an active learning variant of the approach, assisting the expert if desired. A deep learning model provides an initial parameter estimate, from which the optimization cycle iteratively refines the design until a termination condition (e.g., energy budget or iteration limit) is met. We demonstrate our approach, based on a sheet metal forming process, and show how it enables us to accelerate the exploration of the design space while reducing the need for expert involvement.
GLA-Grad++: An Improved Griffin-Lim Guided Diffusion Model for Speech Synthesis
Baoueb, Teysir, Bie, Xiaoyu, Fontaine, Mathieu, Richard, Gaรซl
Recent advances in diffusion models have positioned them as powerful generative frameworks for speech synthesis, demonstrating substantial improvements in audio quality and stability. Nevertheless, their effectiveness in vocoders conditioned on mel spectrograms remains constrained, particularly when the conditioning diverges from the training distribution. The recently proposed GLA-Grad model introduced a phase-aware extension to the WaveGrad vocoder that integrated the Griffin-Lim algorithm (GLA) into the reverse process to reduce inconsistencies between generated signals and conditioning mel spectrogram. In this paper, we further improve GLA-Grad through an innovative choice in how to apply the correction. Particularly, we compute the correction term only once, with a single application of GLA, to accelerate the generation process. Experimental results demonstrate that our method consistently outperforms the baseline models, particularly in out-of-domain scenarios.
The Hidden Cost of Approximation in Online Mirror Descent
Schlisselberg, Ofir, Sherman, Uri, Koren, Tomer, Mansour, Yishay
Online mirror descent (OMD) is a fundamental algorithmic paradigm that underlies many algorithms in optimization, machine learning and sequential decision-making. The OMD iterates are defined as solutions to optimization subproblems which, oftentimes, can be solved only approximately, leading to an inexact version of the algorithm. Nonetheless, existing OMD analyses typically assume an idealized error free setting, thereby limiting our understanding of performance guarantees that should be expected in practice. In this work we initiate a systematic study into inexact OMD, and uncover an intricate relation between regularizer smoothness and robustness to approximation errors. When the regularizer is uniformly smooth, we establish a tight bound on the excess regret due to errors. Then, for barrier regularizers over the simplex and its subsets, we identify a sharp separation: negative entropy requires exponentially small errors to avoid linear regret, whereas log-barrier and Tsallis regularizers remain robust even when the errors are only polynomial. Finally, we show that when the losses are stochastic and the domain is the simplex, negative entropy regains robustness-but this property does not extend to all subsets, where exponentially small errors are again necessary to avoid suboptimal regret.
TreeCoder: Systematic Exploration and Optimisation of Decoding and Constraints for LLM Code Generation
Princis, Henrijs, Sharma, Arindam, David, Cristina
Large language models (LLMs) have shown remarkable ability to generate code, yet their outputs often violate syntactic or semantic constraints when guided only through natural language prompts. We introduce TreeCoder, the most general and flexible framework to date for exploring decoding strategies, constraints, and hyperparameters in LLMs, and use it in code generation to enforce correctness and structure during decoding rather than relying on prompt engineering. TreeCoder represents decoding as a tree search over candidate programs, where both decoding strategies and constraint functions - such as style, syntax, execution - are treated as first-class, optimisable components. This design enables systematic exploration and automatic tuning of decoding configurations using standard optimisation techniques. Experiments on the MBPP (Python) and SQL-Spider benchmarks show that TreeCoder consistently improves accuracy across open-source models such as CodeLlama, Mistral and DeepSeek, often outperforming their unconstrained baselines by considerable margins.
RecToM: A Benchmark for Evaluating Machine Theory of Mind in LLM-based Conversational Recommender Systems
Li, Mengfan, Shi, Xuanhua, Deng, Yang
Large Language models are revolutionizing the conversational recommender systems through their impressive capabilities in instruction comprehension, reasoning, and human interaction. A core factor underlying effective recommendation dialogue is the ability to infer and reason about users' mental states (such as desire, intention, and belief), a cognitive capacity commonly referred to as Theory of Mind. Despite growing interest in evaluating ToM in LLMs, current benchmarks predominantly rely on synthetic narratives inspired by Sally-Anne test, which emphasize physical perception and fail to capture the complexity of mental state inference in realistic conversational settings. Moreover, existing benchmarks often overlook a critical component of human ToM: behavioral prediction, the ability to use inferred mental states to guide strategic decision-making and select appropriate conversational actions for future interactions. To better align LLM-based ToM evaluation with human-like social reasoning, we propose RecToM, a novel benchmark for evaluating ToM abilities in recommendation dialogues. RecToM focuses on two complementary dimensions: Cognitive Inference and Behavioral Prediction. The former focus on understanding what has been communicated by inferring the underlying mental states. The latter emphasizes what should be done next, evaluating whether LLMs can leverage these inferred mental states to predict, select, and assess appropriate dialogue strategies. Extensive experiments on state-of-the-art LLMs demonstrate that RecToM poses a significant challenge. While the models exhibit partial competence in recognizing mental states, they struggle to maintain coherent, strategic ToM reasoning throughout dynamic recommendation dialogues, particularly in tracking evolving intentions and aligning conversational strategies with inferred mental states.
FedRE: A Representation Entanglement Framework for Model-Heterogeneous Federated Learning
Yao, Yuan, Wang, Lixu, Wu, Jiaqi, Song, Jin, Chen, Simin, Wang, Zehua, Tian, Zijian, Chen, Wei, Li, Huixia, Li, Xiaoxiao
Federated learning (FL) enables collaborative training across clients without compromising privacy. While most existing FL methods assume homogeneous model architectures, client heterogeneity in data and resources renders this assumption impractical, motivating model-heterogeneous FL. To address this problem, we propose Federated Representation Entanglement (FedRE), a framework built upon a novel form of client knowledge termed entangled representation. In FedRE, each client aggregates its local representations into a single entangled representation using normalized random weights and applies the same weights to integrate the corresponding one-hot label encodings into the entangled-label encoding. Those are then uploaded to the server to train a global classifier. During training, each entangled representation is supervised across categories via its entangled-label encoding, while random weights are resampled each round to introduce diversity, mitigating the global classifier's overconfidence and promoting smoother decision boundaries. Furthermore, each client uploads a single cross-category entangled representation along with its entangled-label encoding, mitigating the risk of representation inversion attacks and reducing communication overhead. Extensive experiments demonstrate that FedRE achieves an effective trade-off among model performance, privacy protection, and communication overhead. The codes are available at https://github.com/AIResearch-Group/FedRE.
An interpretable unsupervised representation learning for high precision measurement in particle physics
Lv, Xing-Jian, Miao, De-Xing, Xu, Zi-Jun, Wang, Jian-Chun
Machine learning, and in particular its modern incarnation of deep learning (DL) [1, 2], has become an indispensable tool in particle physics, a field that routinely handles vast datasets and nonlinear relationships among observables [3-6]. In recent years, advances in DL have expanded the scope of data-driven progress across the energy, intensity, accelerator, and cosmic frontiers [7, 8]. Despite remarkable advancements, most current DL applications in particle physics are supervised, relying either on Monte Carlo (MC) simulations or on labeled experimental data. However, because simulations cannot fully capture the complexity of the real world, a persistent gap between MC and Data leads to training bias. Direct training on real data, in turn, demands extensive human labeling, which is labor-intensive and hard to scale [9]. For this reason, the development of unsupervised DL [10, 11] is integral for particle physics. Unsupervised learning has achieved remarkable success in tasks such as clustering [12, 13], anomaly detection [14, 15], and learning representations [16, 17].
Evaluating Embedding Models and Pipeline Optimization for AI Search Quality
Zhong, Philip, Chen, Kent, Wang, Don
We evaluate the performance of various text embedding models and pipeline configurations for AI-driven search systems. We compare sentence-transformer and generative embedding models (e.g., All-MPNet, BGE, GTE, and Qwen) at different dimensions, indexing methods (Milvus HNSW/IVF), and chunking strategies. A custom evaluation dataset of 11,975 query-chunk pairs was synthesized from US City Council meeting transcripts using a local large language model (LLM). The data pipeline includes preprocessing, automated question generation per chunk, manual validation, and continuous integration/continuous deployment (CI/CD) integration. We measure retrieval accuracy using reference-based metrics: Top-K Accuracy and Normalized Discounted Cumulative Gain (NDCG). Our results demonstrate that higher-dimensional embeddings significantly boost search quality (e.g., Qwen3-Embedding-8B/4096 achieves Top-3 accuracy about 0.571 versus 0.412 for GTE-large/1024), and that neural re-rankers (e.g., a BGE cross-encoder) further improve ranking accuracy (Top-3 up to 0.527). Finer-grained chunking (512 characters versus 2000 characters) also improves accuracy. We discuss the impact of these factors and outline future directions for pipeline automation and evaluation.
DeepPNI: Language- and graph-based model for mutation-driven protein-nucleic acid energetics
Mondal, Somnath, Mondal, Tinkal, Pramanik, Soumajit, Mehra, Rukmankesh
The interaction between proteins and nucleic acids is crucial for processes that sustain cellular function, including DNA maintenance and the regulation of gene expression and translation. Amino acid mutat ions in protein - nucleic acid complexes often lead to vital disease s . Experimental techniques have their own specific limitations in predicting mutational effects in protein - nucleic acid complexes . In this study, we compiled a large dataset of 1951 mutations including both protein - DNA and protein - RNA complexes and integrate d structural and sequential features to build a deep learning - based regression model named DeepPNI . This model estimates mutation - induced binding free energy changes in protein - nucleic aci d complexes . The structural feature s are encoded via edge - aware RGCN and the sequential feature s are extracted using protein language model ESM - 2. W e have achieved a high average Pearson correlation coeffi cient (PCC) of 0.76 in the large dataset via five - fold cross - validation. Consistent performance across individual dataset of protein - DNA, protein - RNA complexes, and different experimental temperature split dataset make the model g eneralizable . Our model showed g ood performance in complex - based five - fold cross - validation, which prove d its robustness. In addition, DeepPNI outperform ed in e xternal dataset validation, and compar ison with existing tools .