Singapore

Foundation Models (FMs) have demonstrated strong generalization across diverse vision tasks. However, their deployment in federated settings is hindered by high computational demands, substantial communication overhead, and significant inference costs. We propose DSFedMed, a dual-scale federated framework that enables mutual knowledge distillation between a centralized foundation model and lightweight client models for medical image segmentation. To support knowledge distillation, a set of high-quality medical images is generated to replace real public datasets, and a learnability-guided sample selection strategy is proposed to enhance efficiency and effectiveness in dual-scale distillation. This mutual distillation enables the foundation model to transfer general knowledge to lightweight clients, while also incorporating client-specific insights to refine the foundation model. Evaluations on five medical imaging segmentation datasets show that DSFedMed achieves an average 2\% improvement in Dice score while reducing communication costs and inference time by nearly 90\% compared to existing federated foundation model baselines. These results demonstrate significant efficiency gains and scalability for resource-limited federated deployments. The code will be made publicly available upon acceptance.

AAAI 2026

DSFedMed: Dual-Scale Federated Medical Image Segmentation via Mutual Distillation Between Foundation and Lightweight Models

generated data

foundation models

federated learning

We are pleased to announce the Fortieth AAAI Conference on Artificial Intelligence (AAAI-26), which will be held in Singapore EXPO from January 20 to January 27, 2026.

The purpose of the AAAI conference series is to promote research in Artificial Intelligence (AI) and foster scientific exchange between researchers, practitioners, scientists, students, and engineers across the entirety of AI and its affiliated disciplines. AAAI-26 will feature technical paper presentations, special tracks, invited speakers, workshops, tutorials, poster sessions, senior member presentations, competitions, and exhibit programs, and a range of other activities to be announced.<br><br>

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We are pleased to announce the Fortieth AAAI Conference on Artificial Intelligence (AAAI-26), which will be held in Singapore EXPO from January 20 to January 27, 2026.

technical paper

Air pollution is a leading global health threat, yet many developing countries lack the dense monitoring infrastructure needed for accurate exposure assessment and informed policy. Optimal Sensor Placement (OSP) is a foundational challenge in expanding monitoring capacity. While mutual information (MI) offers a principled criterion for selecting informative sensor locations, its computational cost grows with both the number of placements and the density of the candidate grid. We present a scalable, continuous optimization framework that treats sensor coordinates as differentiable parameters and directly maximizes MI. Unlike standard approaches, our method is computationally efficient—its runtime is independent of both the number of placements and the size of the search grid—making MI-based acquisition feasible over large spatial domains. On a continental-scale PM$_{2.5}$ dataset, our method outperforms random placement and the widely-used Maximum Predictive Variance heuristic. In a focused regional study, it approaches the performance of greedy MI while being orders of magnitude faster. Our framework enables practical, information-theoretic sensor placement for real-world environmental monitoring.

Scalable Air-Quality Sensor Placement via Gradient-Based Mutual Information Maximization

Adolescents struggle to understand bias and representation
in AI, particularly the concept of how datasets used in
machine learning can be representative of populations or
not. Within early experiments in teaching about
investigating bias in AI systems using the Developing AI
Literacy (DAILy) curriculum, we observed participating
youth struggling to understand what it meant to be
represented in the output of AI tools. For example, when
using Google Image Search with prompts such as “physicist”
and “outdoor recreation,” participating youth did not
understand the question, “Are you represented in this
outcome?” We saw an opportunity to address this challenge
using the Kapor Foundation's Responsible AI and Tech
Justice Guide. Drawing insights from three of the six core
components of the framework presented in the guide, we
developed Games of Representation (GR), a series of three
card-based activities using SET game cards to teach
concepts of population, sample, dataset, and
representation. Through game play, players manipulate
datasets, role-play as stakeholders with competing
interests, and explore real-world scenarios where
representation matters. The GR games and corresponding
guide provide educators, families, and care providers with
flexible, hands-on activities for guided, playful
conversations with adolescents about AI ethics. This work
contributes practical resources for K-12 AI education while
addressing critical gaps in youth understanding of
statistical bias and stakeholder influence in AI
development.

Games of Representation: Developing Card-Based Activities to Teach About Representation and Bias in AI Datasets

Graph Neural Networks (GNNs) excel at modeling graph data but often amplify biases tied to sensitive attributes like gender and race. Existing causality-based methods use isolated interventions on graph topology or features, yet struggle to produce representations that balance predictive power with fairness. This leads to two issues: (1) weak predictive power, where representations miss critical task-relevant features, and (2) bias amplification, where representations encode sensitive attributes, causing unfair outcomes. 
To address these issues, we introduce the Probability of Necessity and Sufficiency (PNS), where necessity ensures representations capture only essential features for predictions, and sufficiency guarantees these features are adequate without relying on sensitive attributes. We propose FairSNR, a fairness-aware graph representation learning framework that introduces constraints based on the PNS. 
Specifically, FairSNR leverages PNS to guide the learning of fair representations from graph data. In particular, FairSNR employs an encoder to learn node representations with high PNS for downstream tasks. To compute and optimize PNS, FairSNR introduces an intervenor that learns to generate the most challenging counterfactual interventions on the representations, thereby enhancing the model’s causal stability even under worst-case scenarios. Finally, a discriminator is trained to detect and mitigate sensitive information leakage in the learned representations, effectively disentangling sensitive biases from task-relevant features. Experiments on real-world graph datasets demonstrate that FairSNR outperforms existing state-of-the-art (SOTA) methods in both fairness and utility.

Learning Fair Graph Representations via Probability of Necessity and Sufficiency

Video-Language Models (LVLMs) have demonstrated impressive multi-modal reasoning capabilities across diverse computer vision applications. However, these VLMs are task-specific and assume that both video and language inputs are complete. However, real-world VLM applications might face challenges due to deactivated sensors (e.g., cameras are unavailable due to data privacy), yielding modality-incomplete data and leading to inconsistency between training and testing data. While straightforward incomplete input can boast training generalization-ability and lead to training failure, its potential risks to VLMs in terms of safety and trustworthiness have been largely neglected. To this end, we make the first attempt to propose a unified incomplete video-language model to process the incomplete multi-modal inputs. Specifically, given incomplete video-text pairs, we first design a multi-modal feature approximation module to construct relational multi-modal graphs based on available cross-modal high semantic similarity features, which can approximate more reliable completion features for the missing modalities. Then, we propose a multi-modal knowledge distillation module to reduce over-reliance on the complete modality. Finally, we propose a multi-granularity multi-modal integration module to integrate semantics-similar video-text pairs by mapping them more compact in the common feature space. Extensive experimental results on several incomplete dataset demonstrate that our method can serve as a plug-and-play module for previous works to improve their performance in various multi-modal tasks.

Towards Unified Vision-Language Models with Incomplete Multi-Modal Inputs

Semi-supervised semantic segmentation (S4) has advanced remote sensing (RS) analysis by leveraging unlabeled data through pseudo-labeling and consistency learning. However, existing S4 studies often rely on small-scale datasets and models, limiting their practical applicability. To address this, we propose S5, the first scalable framework for semi-supervised semantic segmentation in RS, which unlocks the potential of vast unlabeled Earth observation data typically underutilized due to costly pixel-level annotations. Built upon existing large-scale RS datasets, S5 introduces a data selection strategy that integrates entropy-based filtering and diversity expansion, resulting in the RS4P-1M dataset. Using this dataset, we systematically scales S4 methods by pre-training RS foundation models (RSFMs) of varying sizes on this extensive corpus, significantly boosting their performance on land cover segmentation and object detection tasks. Furthermore, during fine-tuning, we incorporate a Mixture-of-Experts (MoE)-based multi-dataset fine-tuning approach, which enables efficient adaptation to multiple RS benchmarks with fewer parameters. This approach improves the generalization and versatility of RSFMs across diverse RS benchmarks. The resulting RSFMs achieve state-of-the-art performance across all benchmarks, underscoring the viability of scaling semi-supervised learning for RS applications. All datasets, code, and models will be released to facilitate further research.

S5: Scalable Semi-Supervised Semantic Segmentation in Remote Sensing

Self-play fine-tuning has emerged as a promising approach to improve Large Language Models (LLMs) without additional human annotations. However, existing methods struggle with complex generation tasks requiring long context understanding, where models produce partially correct outputs interleaved with errors. Traditional approaches train on entire sequences uniformly, failing to distinguish between well-predicted and erroneous regions, leading to diluted learning signals and slow convergence. We propose DRIFT (Difference-aware Reinforcement through Iterative Fine-Tuning), a novel self-play framework that selectively trains on prediction differences. DRIFT introduces two key innovations: (1) Difference-Aware Masking (DAM) that identifies and masks common subsequences between model outputs and ground truth, focusing training exclusively on error regions; (2) Occurrence-Aware Loss (OAL) that provides position-invariant vocabulary supervision, complementing the position-sensitive adversarial loss. This dual mechanism enables models to correct both positional and lexical errors effectively. Theoretically, we prove that DRIFT converges when masked distributions align. Empirically, we evaluate DRIFT on diverse summarization benchmarks using Qwen2.5-3B and LLaMA-3.1-8B models. Results show that DRIFT significantly outperforms both supervised fine-tuning (SFT) and self-play fine-tuning (SPIN), achieving up to 16\% improvement on SAMSum dialogue summarization tasks while maintaining general capabilities. Notably, DRIFT breaks the performance ceiling of continued SFT and demonstrates superior efficiency compared to holistic self-play methods, validating that targeted optimization on prediction differences is crucial for structured text generation tasks.

DRIFT: Difference-Aware Reinforcement Through Iterative Fine-Tuning for Language Model

Establishing convergent semantics for weighted argumentation graph is a fundamental and long-standing issue. Particularly, it is challenging to develop convergent semantics for weighted bipolar argumentation graph (wBAG), which include both support and attack relations on weighted arguments. Existing semantics in the literature are not general enough in the sense that they only apply to acyclic graphs or special cyclic cases. In this paper, we provide a general and elegant solution to this issue by adopting the so-called bilateral gradual semantics, so that the strength of arguments can be defined as the limits of iterative functions that always converge for any wBAG including cyclic ones. A preliminary experimental analysis shows that our semantics appear quite efficient in calculating argument strength. Overall, this paper offers a solid and promising foundation for weighted bipolar argumentation in theoretical and practical aspects.

Convergent Semantics for Weighted Bipolar Argumentation

Medical image segmentation plays a critical role in clinical diagnosis, lesion quantification, and preoperative planning. However, conventional Mamba-based architectures, which rely on fixed-directional sequence modeling and flattening of images into one-dimensional sequences, fail to effectively capture hierarchical anatomical features and spatial dependencies, limiting their representation capacity for complex medical structures. To address these challenges, we propose EccoMamba (Enhanced Cross-hierarchical Continuity Orthogonal Mamba), a U-shaped encoder-decoder framework tailored for medical image segmentation. In the encoder’s downsampling path, we introduce the hierarchical aggregation enhancement (HAE) module, which integrates multi-scale convolutions with hierarchical attention. The attention branch further incorporates cross-channel interactions, enabling the model to amplify semantically relevant features and suppress background noise selectively. For skip connections, we design the structural continuity orthogonal (SCO) module to maintain spatial continuity by modeling cross-dimensional dependencies via orthogonal axial shifts, mitigating directional bias and enhancing anatomical consistency. Extensive experiments on four benchmark datasets, ISIC 2018, ISIC 2017, Synapse, and ACDC, demonstrate that EccoMamba consistently outperforms state-of-the-art methods in both segmentation accuracy and structural fidelity. The code is available at https://anonymous.4open.science/r/EccoMamba-4117/.

EccoMamba: Enhanced Cross-hierarchical Continuity Orthogonal Mamba for Medical Image Segmentation

Ordinal classification has been widely applied in many high-stakes applications, e.g., medical imaging and diagnosis, where reliable uncertainty quantification (UQ) is essential for decision making. Conformal prediction (CP) is a general UQ framework that provides statistically valid guarantees, which is especially useful in practice. However, prior ordinal CP methods mainly focus on heuristic algorithms or restrictively require the underlying model to predict a unimodal distribution over ordinal labels. Consequently, they lack either a comprehensive understanding of the it coverage optimality and predictive efficiency, or a model-agnostic and distribution-free nature favored by CP methods. To this end, we fill this gap by proposing the first ordinal-CP method that is both model-agnostic and provably optimal. Specifically, we formulate conformal ordinal classification as an expected minimum-length covering problem over the underlying distribution. To solve this problem, we develop a sliding-window algorithm that is optimal for each calibration example, with only a linear time complexity in K, the number of label candidates. The local optimality per instance further yields global optimality in expectation.
Moreover, we propose a length-regularized variant that shrinks prediction set size while preserving coverage. Extensive experiments on three benchmark datasets from diverse domains have been conducted to demonstrate the significantly improved predictive efficiency of the proposed methods over baselines (by 18% on average over three datasets).

Minimum-Length Conformal Prediction Sets for Ordinal Classification

Domain Generalization (DG) requires models to generalize across unseen data distributions. Kernel-based theory reveals a No-Free-Lunch problem: any model with a fixed representation is fundamentally sub-optimal for all possible shifts. While large ensembles mitigate this, they are computationally expensive and remain static once trained, inheriting the same theoretical limitation. We introduce MoE$^2$ (Mixture-of-Mixtures of Experts), a framework that uses a single frozen backbone to dynamically synthesize a bespoke adapter for each input, allowing it to continuously adapt its effective kernel. We provide a theoretical grounding for this process, proving our routing mechanism is a principled non-parametric estimator for the optimal Bayes mixture of experts. We derive a generalization bound that cleanly separates the router's estimation error from the reduction in a kernel-mismatch penalty achieved via synthesis. MoE$^2$ matches or exceeds state-of-the-art ensemble baselines on major DG benchmarks while using only a single, compact model. MoE$^2$ thus provides a theoretically-grounded and lightweight alternative to large-scale ensembles for robust domain generalization.

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Scalable Air-Quality Sensor Placement via Gradient-Based Mutual Information Maximization

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