Deep Learning
FlowRL: Matching Reward Distributions for LLM Reasoning
Zhu, Xuekai, Cheng, Daixuan, Zhang, Dinghuai, Li, Hengli, Zhang, Kaiyan, Jiang, Che, Sun, Youbang, Hua, Ermo, Zuo, Yuxin, Lv, Xingtai, Zhang, Qizheng, Chen, Lin, Shao, Fanghao, Xue, Bo, Song, Yunchong, Yang, Zhenjie, Cui, Ganqu, Ding, Ning, Gao, Jianfeng, Liu, Xiaodong, Zhou, Bowen, Mei, Hongyuan, Lin, Zhouhan
We propose FlowRL: matching the full reward distribution via flow balancing instead of maximizing rewards in large language model (LLM) reinforcement learning (RL). Recent advanced reasoning models adopt reward-maximizing methods (\eg, PPO and GRPO), which tend to over-optimize dominant reward signals while neglecting less frequent but valid reasoning paths, thus reducing diversity. In contrast, we transform scalar rewards into a normalized target distribution using a learnable partition function, and then minimize the reverse KL divergence between the policy and the target distribution. We implement this idea as a flow-balanced optimization method that promotes diverse exploration and generalizable reasoning trajectories. We conduct experiments on math and code reasoning tasks: FlowRL achieves a significant average improvement of $10.0\%$ over GRPO and $5.1\%$ over PPO on math benchmarks, and performs consistently better on code reasoning tasks. These results highlight reward distribution-matching as a key step toward efficient exploration and diverse reasoning in LLM reinforcement learning.
3DViT-GAT: A Unified Atlas-Based 3D Vision Transformer and Graph Learning Framework for Major Depressive Disorder Detection Using Structural MRI Data
Alotaibi, Nojod M., Alhothali, Areej M., Ali, Manar S.
Major depressive disorder (MDD) is a prevalent mental health condition that negatively impacts both individual well-being and global public health. Automated detection of MDD using structural magnetic resonance imaging (sMRI) and deep learning (DL) methods holds increasing promise for improving diagnostic accuracy and enabling early intervention. Most existing methods employ either voxel-level features or handcrafted regional representations built from predefined brain atlases, limiting their ability to capture complex brain patterns. This paper develops a unified pipeline that utilizes Vision Transformers (ViTs) for extracting 3D region embeddings from sMRI data and Graph Neural Network (GNN) for classification. We explore two strategies for defining regions: (1) an atlas-based approach using predefined structural and functional brain atlases, and (2) an cube-based method by which ViTs are trained directly to identify regions from uniformly extracted 3D patches. Further, cosine similarity graphs are generated to model interregional relationships, and guide GNN-based classification. Extensive experiments were conducted using the REST-meta-MDD dataset to demonstrate the effectiveness of our model. With stratified 10-fold cross-validation, the best model obtained 81.51\% accuracy, 85.94\% sensitivity, 76.36\% specificity, 80.88\% precision, and 83.33\% F1-score. Further, atlas-based models consistently outperformed the cube-based approach, highlighting the importance of using domain-specific anatomical priors for MDD detection.
Prior-Guided Flow Matching for Target-Aware Molecule Design with Learnable Atom Number
Zhou, Jingyuan, Qian, Hao, Tu, Shikui, Xu, Lei
Structure-based drug design (SBDD), aiming to generate 3D molecules with high binding affinity toward target proteins, is a vital approach in novel drug discovery. Although recent generative models have shown great potential, they suffer from unstable probability dynamics and mismatch between generated molecule size and the protein pockets geometry, resulting in inconsistent quality and off-target effects. We propose PAFlow, a novel target-aware molecular generation model featuring prior interaction guidance and a learnable atom number predictor. PAFlow adopts the efficient flow matching framework to model the generation process and constructs a new form of conditional flow matching for discrete atom types. A protein-ligand interaction predictor is incorporated to guide the vector field toward higher-affinity regions during generation, while an atom number predictor based on protein pocket information is designed to better align generated molecule size with target geometry. Extensive experiments on the CrossDocked2020 benchmark show that PAFlow achieves a new state-of-the-art in binding affinity (up to -8.31 Avg. Vina Score), simultaneously maintains favorable molecular properties.
Linear-Time Demonstration Selection for In-Context Learning via Gradient Estimation
Zhang, Ziniu, Zhang, Zhenshuo, Li, Dongyue, Wang, Lu, Dy, Jennifer, Zhang, Hongyang R.
This paper introduces an algorithm to select demonstration examples for in-context learning of a query set. Given a set of $n$ examples, how can we quickly select $k$ out of $n$ to best serve as the conditioning for downstream inference? This problem has broad applications in prompt tuning and chain-of-thought reasoning. Since model weights remain fixed during in-context learning, previous work has sought to design methods based on the similarity of token embeddings. This work proposes a new approach based on gradients of the output taken in the input embedding space. Our approach estimates model outputs through a first-order approximation using the gradients. Then, we apply this estimation to multiple randomly sampled subsets. Finally, we aggregate the sampled subset outcomes to form an influence score for each demonstration, and select $k$ most relevant examples. This procedure only requires pre-computing model outputs and gradients once, resulting in a linear-time algorithm relative to model and training set sizes. Extensive experiments across various models and datasets validate the efficiency of our approach. We show that the gradient estimation procedure yields approximations of full inference with less than ${1}\%$ error across six datasets. This allows us to scale up subset selection that would otherwise run full inference by up to ${37.7}\times$ on models with up to $34$ billion parameters, and outperform existing selection methods based on input embeddings by ${11}\%$ on average.
Street Review: A Participatory AI-Based Framework for Assessing Streetscape Inclusivity
Mushkani, Rashid, Koseki, Shin
City streets, sidewalks, and public areas often serve as primary interaction points among diverse user groups, including residents, commuters, and visitors ( Gehl, 2011). These spaces carry social, economic, and cultural signifi - cance that influences navigation and user experience ( Mitra ˇ sinovi c & Mehta, 2021). Municipal governments and planning agencies recognize the importance of inclusive public spaces but face challenges in operation - alizing inclusivity ( Anttiroiko & De Jong, 2020). Traditional approaches may draw on universal design principles intended to accommodate a broad range of users, but these frameworks often take a one-size-fits-all approach that prioritizes physical accessibility over the social and cul - tural dimensions of public space use ( Low, 2020). In multicultural cities, where multiple languages, cultures, and religious practices converge, these complexities become particularly evident ( Fan et al., 2023; Lit - man, 2025; Salgado et al., 2021; Youngbloom et al., 2023). Research on inclusive design has provided valuable insights, but few methods combine qualitative depth with quantitative scale to under - stand inclusivity in urban contexts ( Anttiroiko & De Jong, 2020; Mehta, 2019; Zamanifard et al., 2019). Ethnographic research and interviews offer detailed perspectives on lived experience, while computer vision and machine learning enable assessments at larger scales ( Ibrahim et al., 2020). However, large-scale computational approaches often overlook intersectional dimensions ( Zhu et al., 2025). This gap calls for integrated models that merge qualitative and quantitative methodologies.
Strategic Communication and Language Bias in Multi-Agent LLM Coordination
Buscemi, Alessio, Proverbio, Daniele, Di Stefano, Alessandro, Han, The Anh, Castignani, German, Liò, Pietro
Large Language Model (LLM)-based agents are increasingly deployed in multi-agent scenarios where coordination is crucial but not always assured. Research shows that the way strategic scenarios are framed linguistically can affect cooperation. This paper explores whether allowing agents to communicate amplifies these language-driven effects. Leveraging FAIRGAME, we simulate one-shot and repeated games across different languages and models, both with and without communication. Our experiments, conducted with two advanced LLMs-GPT-4o and Llama 4 Maverick-reveal that communication significantly influences agent behavior, though its impact varies by language, personality, and game structure. These findings underscore the dual role of communication in fostering coordination and reinforcing biases.
Talk2Event: Grounded Understanding of Dynamic Scenes from Event Cameras
Kong, Lingdong, Lu, Dongyue, Liang, Ao, Li, Rong, Dong, Yuhao, Hu, Tianshuai, Ng, Lai Xing, Ooi, Wei Tsang, Cottereau, Benoit R.
Event cameras offer microsecond-level latency and robustness to motion blur, making them ideal for understanding dynamic environments. Yet, connecting these asynchronous streams to human language remains an open challenge. We introduce Talk2Event, the first large-scale benchmark for language-driven object grounding in event-based perception. Built from real-world driving data, we provide over 30,000 validated referring expressions, each enriched with four grounding attributes -- appearance, status, relation to viewer, and relation to other objects -- bridging spatial, temporal, and relational reasoning. To fully exploit these cues, we propose EventRefer, an attribute-aware grounding framework that dynamically fuses multi-attribute representations through a Mixture of Event-Attribute Experts (MoEE). Our method adapts to different modalities and scene dynamics, achieving consistent gains over state-of-the-art baselines in event-only, frame-only, and event-frame fusion settings. We hope our dataset and approach will establish a foundation for advancing multimodal, temporally-aware, and language-driven perception in real-world robotics and autonomy.
Unit-Based Histopathology Tissue Segmentation via Multi-Level Feature Representation
Shakarami, Ashkan, Farshad, Azade, Yeganeh, Yousef, Nicole, Lorenzo, Schüffler, Peter, Ghidoni, Stefano, Navab, Nassir
We propose UTS, a unit-based tissue segmentation framework for histopathology that classifies each fixed-size 32 32 tile, rather than each pixel, as the segmentation unit. This approach reduces annotation effort and improves computational efficiency without compromising accuracy. To implement this approach, we introduce a Multi-Level Vi sion Transformer (L-ViT), which benefits the multi-level feature representation to capture both fine-grained morphology and global tissue context. Trained to segment breast tissue into three categories ( infiltrating tumor, non-neoplastic stroma, and fat), UTS supports clinically relevant tasks such as tumor-stroma quantification and surgical margin assessment. Evaluated on 386,371 tiles from 459 H&E-stained regions, it outperforms U-Net variants and transformer-based baselines. Code and Dataset will be available at GitHub.
The Dark Side of LLMs: Agent-based Attacks for Complete Computer Takeover
Lupinacci, Matteo, Pironti, Francesco Aurelio, Blefari, Francesco, Romeo, Francesco, Arena, Luigi, Furfaro, Angelo
The rapid adoption of Large Language Model (LLM) agents and multi-agent systems enables remarkable capabilities in natural language processing and generation. However, these systems introduce security vulnerabilities that extend beyond traditional content generation to system-level compromises. This paper presents a comprehensive evaluation of the LLMs security used as reasoning engines within autonomous agents, highlighting how they can be exploited as attack vectors capable of achieving computer takeovers. We focus on how different attack surfaces and trust boundaries can be leveraged to orchestrate such takeovers. We demonstrate that adversaries can effectively coerce popular LLMs into autonomously installing and executing malware on victim machines. Our evaluation of 18 state-of-the-art LLMs reveals an alarming scenario: 94.4% of models succumb to Direct Prompt Injection, and 83.3% are vulnerable to the more stealthy and evasive RAG Backdoor Attack. Notably, we tested trust boundaries within multi-agent systems, where LLM agents interact and influence each other, and we revealed that LLMs which successfully resist direct injection or RAG backdoor attacks will execute identical payloads when requested by peer agents. We found that 100.0% of tested LLMs can be compromised through Inter-Agent Trust Exploitation attacks, and that every model exhibits context-dependent security behaviors that create exploitable blind spots.
MediQ-GAN: Quantum-Inspired GAN for High Resolution Medical Image Generation
Jiao, Qingyue, Tang, Yongcan, Zhuang, Jun, Cong, Jason, Shi, Yiyu
Machine learning-assisted diagnosis shows promise, yet medical imaging datasets are often scarce, imbalanced, and constrained by privacy, making data augmentation essential. Classical generative models typically demand extensive computational and sample resources. Quantum computing offers a promising alternative, but existing quantum-based image generation methods remain limited in scale and often face barren plateaus. We present MediQ-GAN, a quantum-inspired GAN with prototype-guided skip connections and a dual-stream generator that fuses classical and quantum-inspired branches. Its variational quantum circuits inherently preserve full-rank mappings, avoid rank collapse, and are theory-guided to balance expressivity with trainability. Beyond generation quality, we provide the first latent-geometry and rank-based analysis of quantum-inspired GANs, offering theoretical insight into their performance. Across three medical imaging datasets, MediQ-GAN outperforms state-of-the-art GANs and diffusion models. While validated on IBM hardware for robustness, our contribution is hardware-agnostic, offering a scalable and data-efficient framework for medical image generation and augmentation.