Federated face generation technology leverages decentralized private data to achieve high-quality face synthesis. However, regulations such as the GDPR confer users the right to be forgotten, necessitating the removal of contributions from specific clients in the global model. Existing generation model unlearning methods are primarily designed for centralized environments and are inadequate for addressing the constraints of data privacy storage and limited client computational resources in federated settings. To address this gap, we propose F2GU, the first federated unlearning framework specifically tailored for face generation models, enabling the effective removal of contributions associated with specific clients (identities) while ensuring privacy. Our proposed Generation Trajectory Redirection method dynamically guides the generation trajectory away from target identities, thereby effectively eliminating contributions from specific clients. Additionally, we devise a Mirroring-guided Trajectory Optimization strategy that constructs a mirror projection utilizing the retained client trajectory origins to ensure the generative capabilities of the model are preserved post-unlearning. We conduct extensive experiments on two mainstream face generation models (GAN and Diffusion Model) across three different datasets.The results indicate that our method demonstrates superior performance in both the success rate of identity unlearning and the preservation of generation quality. The code can be available at https://github.com/FanQi-AI/FFGU.

One-shot Federated Learning (FL) enables collaborative model training through a single round of communication, thereby significantly reducing communication overhead. However, in multimodal settings, client data heterogeneity and modality heterogeneity make it difficult to accurately learn the global multimodal representation within a single communication round. We propose Diverse Synthetic Feature Optimization (DSFO) for one-shot MFL framework that achieves global modality consensus via a single communication round. DSFO introduces: (1) Dynamic Probabilistic Scheduling Model Queue (DPSMQ), which ensures local multimodal feature-level distillation quality through diversity-aware model sampling from the queue, directly transmitting synthetic features can significantly reduces the risk of misleading knowledge transfer and (2) Pareto-Optimal Global Feature Consensus (POGFC), a server-side multi-objective optimization that extracts maximally representative synthetic features per modality-category pair to mitigate data heterogeneity, supported by theoretical guarantees in the appendix. Experiments on multimodal datasets demonstrate that DSFO outperforms current methods while significantly reducing communication overhead.

The federated learning (FL) paradigm can significantly solve the rising public concern about data privacy in affective computing. However, conventional FL methods perform poorly due to the uniqueness of the task, as the personalized emotion data vary from client to client. To resolve the privacy-utility paradox, this work proposes a framework that largely improves federated affective computing (FAC) via calibrating the global feature space and communicating privacy-agnostic auxiliary information. The framework consists of two components: first, an emotion hemisphere (EH) representation structure is proposed, which utilizes emotional prior knowledge to unify the emotion global feature space of different clients. Second, the server uses the normalized parameter importance matrix to guide the model aggregation. It retains crucial parameters for individual local models, thereby alleviating the slow convergence problem in the global model caused by the skewed label distribution. The proposed framework yields significant performance gains, and extensive experiments on three emotion datasets demonstrate the effectiveness and the practicality of our approach.

The remarkable generalization of large-scale models has recently gained significant attention in multimodal research. However, deploying heterogeneous large-scale models with different modalities under Federated Learning (FL) to protect data privacy imposes tremendous challenges on clients' limited computation and storage. In this work, we propose M$^2$FedSA to address the above issue. We realize modularized decomposition of large-scale models via Split Learning (SL) and only retain privacy-sensitive modules on clients, alleviating storage overhead. By freezing large-scale models and introducing two specialized lightweight adapters, the models can better focus on task-specific knowledge and enhance modality-specific knowledge, improving the model's adaptability to different tasks while balancing efficiency. In addition, M$^2$FedSA further improves performance by transferring multimodal knowledge to unimodal clients at both the feature and decision levels, which leverages the complementarity of different modalities. Extensive experiments on various multimodal classification tasks validate the effectiveness of our proposed M$^2$FedSA. The code is made available publicly at https://github.com/M2FedSA/M-2FedSA.

In the evolving landscape of federated learning (FL), the integration of multimodal data presents both unprecedented opportunities and significant challenges. Existing works fall short of meeting the growing demand for systems that can efficiently handle diverse tasks and modalities in rapidly changing environments. We propose a meta learning strategy tailored for Multimodal Federated Learning in a multitask setting, which harmonizes intra-modal and inter-modal feature spaces through the Cross-Modal Meta Consensus. This innovative approach enables seamless integration and transfer of knowledge across different data types, enhancing task personalization within modalities and facilitating effective cross-modality knowledge sharing. Additionally, we introduce Gradient Consistency-based Clustering for multimodal convergence, specifically designed to resolve conflicts at meta-initialization points arising from diverse modality distributions, supported by theoretical guarantees. Our approach, evaluated as M3Fed on five federated datasets, with at most four modalities and four downstream tasks, demonstrates strong performance across diverse data distributions, affirming its effectiveness in Multimodal Federated Learning.

Federated affective computing, which deploys traditional affective computing in a distributed framework, achieves a trade-off between privacy and utility, and offers a wide variety of applications in business and society. However, the expensive annotation cost of obtaining reliable emotion labels at the local client remains a barrier to the effective use of local emotional data. Therefore, we propose a federated active affective paradigm to improve the performance of federated affective computing with a limited annotation budget on the client. A major challenge in federated active learning is the inconsistency between the active sampling goals of global and local models, particularly in scenarios with Non-IID data across clients, which exacerbates the problem. To address the above challenge, we propose AffectFAL, a federated active affective computing framework. It incorporates a Preference-aware Group Aggregation module, which obtains global models representing the different emotional preferences among clients. We also devise a tailored De-biased Federated Active Sampling strategy with an improved vote entropy, facilitating class balancing of labeled samples and alleviating the problem of sampling goals inconsistency between the global and local models. We evaluate AffectFAL on diverse benchmarks (image, video and physiological signal) and experimental settings for affective computing. Thorough comparisons with other active sampling strategies demonstrate our method's advantages in affective computing for Non-IID federated learning.

The explosion of video data brings new opportunities and challenges for emotion recognition. Video emotion applications have great commercial value, but the potential to involve illegal snooping on personal feelings has led to controversy over privacy protection. The federated learning (FL) paradigm can substantially address the growing public concerns about data privacy in video emotion recognition. However, conventional FL methods perform poorly due to the uniqueness of the task: the data are heterogeneous across clients induced by emotional label skew and cross-culture expression differences. To mitigate the heterogeneous data, we propose EmoFed, a practical framework of federated learning video-based emotion recognition via multi-group clustering and privacy-agnostic hybrid aggregation. It yields a generically applicable and improved model while protecting privacy, which trains local models under group-aware personalized aggregation. To further encourage communicating comprehensive and privacy-agnostic information among clients, we upload model parameters of both the global layers and personalization layers to the server. We utilize the homomorphically encrypted method for personalization layers, which incurs no learning accuracy loss since no noise is added to the model updates during the encryption/decryption process. The proposed method works on video-based emotion recognition tasks to predict actors' emotional expressions and induced emotion by viewers. Extensive experiments and ablation studies on four benchmarks have demonstrated the efficacy and practicability of our method.