论文检索

Social Aspects · Trustworthy Machine Learning

Aaryan Chandna, Lukas Fluri, Micah Carroll

*Language Models Learn to Mislead Humans Via RLHF* (published at ICLR 2025) argues that RLHF can unintentionally train models to mislead humans – a phenomenon termed Unintentional-SOPHISTRY. However, our review of the paper's code and experiments suggests that a significant portion of their empirical findings may be due largely to major bugs that make the RLHF setup both unrealistic and highly prone to reward hacking. In addition to high-level claims, we correct these issues for one of their experiments, and fail to find evidence that supports the original paper's claims.

Juntai Cao, Xiang Zhang, Raymond Li, Jiarui Ding

Understanding how transformers represent and transform internal features is a core challenge in mechanistic interpretability. Traditional tools like attention maps and probing reveal only partial structure, often blurred by polysemanticity and superposition. New model-based methods offer more principled insight: Sparse Autoencoders extract sparse, interpretable features from dense activations; Semi-Nonnegative Matrix Factorization uncovers how neuron groups themselves encode concepts; Cross-Layer Transcoders track how these representations evolve across depth; and Weight-Sparse Transformers encourage inherently modular computation through architectural sparsity. Together, these approaches provide complementary pathways for opening the black box and understanding the circuits that underpin transformer behavior.

Computer Vision · Vision Models & Multimodal

Anbu Huang

This blogpost develops a geometric and probabilistic lens on diffusion priors for inverse problems. We show that a wide range of methods mostly instantiate two operator-splitting paradigms, i.e., posterior-guided sampling and clean-space local-MAP optimization. Through manifold diagrams, Tweedie-based animations, and step-by-step derivations, we explain how these paradigms decouple a pretrained diffusion prior from measurement physics, clarify when they approximate full posterior sampling versus MAP estimation, and distill practical design rules for building robust diffusion-based inverse solvers.

Computer Vision · Everything Else

Rupa Kurinchi-Vendhan, Pratyusha Sharma, Antonio Torralba, Sara Beery

Scientific and environmental imagery often suffer from complex mixtures of noise related to the sensor and the environment. Existing restoration methods typically remove one degradation at a time, leading to cascading artifacts, overcorrection, or loss of meaningful signal. In scientific applications, restoration must be able to simultaneously handle compound degradations while allowing experts to selectively remove subsets of distortions without erasing important features. To address these challenges, we present PRISM (Precision Restoration with Interpretable Separation of Mixtures). PRISM is a prompted conditional diffusion framework which combines compound-aware supervision over mixed degradations with a weighted contrastive disentanglement objective that aligns primitives and their mixtures in the latent space. This compositional geometry enables high-fidelity joint removal of overlapping distortions while also allowing flexible, targeted fixes through natural language prompts. Across microscopy, wildlife monitoring, remote sensing, and urban weather datasets, PRISM outperforms state-of-the-art baselines on complex compound degradations, including zero-shot mixtures not seen during training. Importantly, we show that selective restoration significantly improves downstream scientific accuracy in several domains over standard ``black-box'' restoration. These results establish PRISM as a generalizable and controllable framework for high-fidelity restoration in domains where scientific utility is a priority.

Deep Learning · Everything Else

Kaitlin Maile, Joao Sacramento

Standard language models often rely on massive parameter counts for their performance, utilizing each parameter only once per inference pass. This prompts consideration of recurrent structures, where models reuse parameters across sequential time, depth, or training progression to achieve improved performance and reduced training cost. We draw connections in the landscape of parameter reuse, from growing models via stacking to recurrent looping, and postulate that these architectural priors act as a form of Latent Chain of Thought (LCoT), allowing models to reason in a continuous state space. By shifting towards deeper and dynamic computation, grown and recurrent architectures offer a path toward improved reasoning in compact networks, ascending beyond scaling laws of standard architectures.

Aryan Sood, Tanvi Sharma, Vansh Agrawal

Large Language Models (LLMs) have brought about a significant change in the field of artificial intelligence, where they have transitioned in scope from being specialized research tools to common resources that drive the next generation of software. With increasing model parameters and training data, LLMs demonstrate new abilities in reasoning, code generation, and solving complex problems that were once considered unattainable. However, scaling these models effectively for long-context applications uniquely poses a challenge. This is primarily due to the inherent limitations of the self-attention mechanism, which has quadratic time complexity. This quadratic bottleneck hinders applications for long documents, high-resolution images, and large codebases, among others. However, what is interesting to observe is that effectively only a few parameters are used in token computation, and most calculations are sparse. Hence, sparsity emerges as an effective solution to this problem. Rather than relying on the entire attention matrix, one can utilize an approximate or sparse version of attention to achieve almost the same results much faster. The backbone of this approach is the idea that tokens do not require the entire context; they only need local context, and thus, most of the computation carried out is wasteful. In this blog, we analyze the types of attention patterns that emerge and how to use them to our advantage for faster and efficient LLMs.

Social Aspects · Everything Else

Lotem Peled-Cohen, Nitay Calderon, Roi Reichart

Can NLP predict heroin-addiction outcomes, uncover suicide risk, or simulate (and even influence) brain activity? Could LLMs one day contribute to research worthy of a Nobel Prize for advancing our understanding of human behavior? And what role do NLP scientists play in shaping that possibility? This post explores these questions, arguing that language technologies are not just tools that support scientific work (like literature search agents, writing tools, or coding assistants), but that by treating language as a window into the human mind, NLP and LLMs can actively help researchers uncover mechanisms of human behavior, cognition, and brain function.

Applications · Robotics

Yitang Li, Zhengyi Luo, Tonghe Zhang, Cunxi Dai, Anssi Kanervisto, Andrea Tirinzoni, Haoyang Weng, Kris Kitani, Mateusz Guzek, Ahmed Touati 等

Building Behavioral Foundation Models (BFMs) for humanoid robots has the potential to unify diverse control tasks under a single, promptable generalist policy. However, existing approaches are either exclusively deployed on simulated humanoid characters, or specialized to specific tasks such as tracking. We propose BFM-Zero, a framework that learns an effective shared latent representation that embeds motions, goals, and rewards into a common space, enabling a single policy to be prompted for multiple downstream tasks without retraining. This well-structured latent space in BFM-Zero enables versatile and robust whole-body skills on a Unitree G1 humanoid in the real world, via diverse inference methods, including zero-shot motion tracking, goal reaching, and reward inference, and few-shot optimization-based adaptation. Unlike prior on-policy reinforcement learning (RL) frameworks, BFM-Zero builds upon recent advancements in unsupervised RL and Forward-Backward (FB) models, which offer an objective-centric, explainable, and smooth latent representation of whole-body motions. We further extend BFM-Zero with critical reward shaping, domain randomization, and history-dependent asymmetric learning to bridge the sim-to-real gap. Those key design choices are quantitatively ablated in simulation. A first-of-its-kind model, BFM-Zero establishes a step toward scalable, promptable behavioral foundation models for whole-body humanoid control. Webpage: https://lecar-lab.github.io/BFM-Zero/

Computer Vision · Vision Models & Multimodal

Anbu Huang

In this post, we reframe continuous-time generative modeling from integrating trajectories to learning two-time operators (flow maps). This operator view unifies diffusion, flow matching, and consistency models, and suggests a practical diagnostic — semigroup-consistent jumps yield both step-robust generation and low compositional drift. We derive Eulerian/Lagrangian distillation objectives and use inpainting experiments to show why semigroup-consistent jumps can be both step-robust and composition-stable.

Theory · Reinforcement Learning and Planning

Qingfeng Lan

Recently, many reinforcement learning (RL) algorithms have been applied to improve the post-training of large language models (LLMs). In this article, we aim to provide a unified perspective on the objectives of these RL algorithms, exploring how they relate to each other through the Policy Gradient Theorem — the fundamental theorem of policy gradient methods.

Deep Learning · Generative Models and Autoencoders

Xiangyu Wen, Junhua Huang, Zeju LI, Min Li, Jianyuan Zhong, Zhijian Xu, Mingxuan Yuan, Yongxiang Huang, Qiang Xu

The prevailing approach to distilling reasoning from Large Language Models (LLMs)—behavioral cloning from textual rationales—is fundamentally limited. It teaches Small Language Models (SLMs) to mimic surface-level patterns rather than the underlying algorithmic structure of thought, resulting in a critical lack of logical robustness. We argue that instead of cloning text, distillation should transfer this algorithmic structure directly. We introduce Reasoning Scaffolding, a framework that reframes reasoning as a structured generation process. Our method first abstracts the teacher's thought process into a sequence of discrete, interpretable semantic signals (e.g., Contrast, Addition) that act as a scaffold. The student model is then trained via a multi-task objective to both (1) predict the next semantic signal, anticipating the reasoning flow, and (2) generate the corresponding step, conditioned on that signal. This multi-task scheme acts as a powerful regularizer, compelling the student to internalize the computational patterns of coherent reasoning. On a suite of challenging reasoning benchmarks, our method significantly outperforms state-of-the-art distillation in both accuracy and logical consistency, providing a path towards creating smaller models that are genuine reasoners, not just fluent mimics.

Zairah Mustahsan

As large language models (LLMs) and agentic systems advance, the field increasingly depends on fine-grained evaluation to compare models, guide research directions, and make deployment decisions. Yet evaluation pipelines often treat LLMs as deterministic functions, even though they are fundamentally stochastic systems with variability arising from sampling methods, hardware nondeterminism, environmental randomness, and evaluation procedures. This mismatch leads to unstable benchmarks, unreliable model comparisons, inconsistent agent outcomes, and significant uncertainty when using LLMs as judges. Recent research has begun to quantify this instability and propose statistical techniques, from frequentist error bars to Bayesian latent-state models, reliability metrics, and large-scale variance audits. But adoption is uneven, and the field lacks a cohesive statistical framework for evaluating stochastic intelligence. This post synthesizes existing research into a unified perspective and outlines practical recommendations for improving evaluation practice. The goal is not to introduce new methods, but to demonstrate that the tools already exist and that incorporating statistical thinking is both feasible and urgently needed.

Qingyun Sun, Zhenheng Tang, Huacan Wang

Large Language Model (LLM) agents now read the world through managed-context pipelines, write to it via tool-calling APIs, and continuously re-wire themselves with fresh experience. Stakeholders therefore need a Generally Accepted Accounting Principles (GAAP) compatible method to price both (i) the agent's labour-like output and (ii) the data traces that fuel learning. We formalise a single unifying metric - agent Economic Value (AEV)- and demonstrate that these metrics are measurable today. We then extend the template to reinforcement-learning regimes in which grounded rewards equal cash flows. Lastly, we propose a financial settlement layer, which transforms the agent from a passive software user into an active economic participant.

Deep Learning · Generative Models and Autoencoders

Zeju LI, Jianyuan Zhong, Ziyang Zheng, Xiangyu Wen, Zhijian Xu, Yingying Cheng, Fan Zhang, Qiang Xu

Large Language Models (LLMs) using Chain-of-Thought (CoT) prompting excel at complex reasoning but generate verbose thought processes with considerable redundancy, leading to increased inference costs and reduced efficiency. We introduce a novel CoT compression framework based on step entropy, a metric that quantifies the informational contribution of individual reasoning steps to identify redundancy. Through theoretical analysis and extensive empirical validation on mathematical reasoning benchmarks, we demonstrate that steps with low entropy are indeed highly redundant. Our experiments reveal that an astonishing 80% of low-entropy intermediate steps can be pruned without significant degradation in the final answer accuracy across DeepSeek-R1-7B, 14B and Qwen3-8B. This finding sharply contrasts with random or high-entropy pruning, which severely impairs reasoning performance. Building on this, we propose a novel two-stage training strategy combining Supervised Fine-Tuning (SFT) and Group Relative Policy Optimization (GRPO) reinforcement learning. This approach enables LLMs to autonomously learn to generate compressed COTs during inference by strategically incorporating [SKIP] tokens. Our method significantly enhances LLM inference efficiency while rigorously preserving accuracy, offering profound implications for practical LLM deployment and a deeper understanding of reasoning structures.

Michael Matthews, Pierluca D'Oro, Anssi Kanervisto, Scott Fujimoto, Jakob Foerster, Mikael Henaff

The NetHack Learning Environment (NLE) was proposed as a challenging benchmark to test an agents abilities to perform complex reasoning over long time horizons in a stochastic, partially-observed, procedurally generated setting. To date, no approach, including those based on reinforcement learning, using large pretrained models, using handcoded symbolic agents, imitating expert trajectories or any hybrid method has achieved significant progress towards completing the game. We take a deeper look into the mechanics and interface of the NLE and show that much of the complexity of NetHack is inaccessible due to constraints on the observation and action spaces. We propose a series of modifications and show that they meaningfully improve performance on the NLE.

Reinforcement Learning · Multi-agent

HyunJi Nam, Yanming Wan, Mickel Liu, Peter Ahnn, Jianxun Lian, Natasha Jaques

As everyday use cases of large language model (LLM) AI assistants have expanded, it is becoming increasingly important to personalize responses to align to different users' preferences and goals. While reinforcement learning from human feedback (RLHF) is effective at improving LLMs to be generally more helpful and fluent, it does not account for variability across users, as it models the entire user population with a single reward model, meaning it assumes that everyone's preferences are the same. We present a novel framework, **P**reference **L**earning **U**sing **S**ummarization (**PLUS**), that uses reinforcement learning (RL) to learn to produce text-based summaries of each user's preferences, characteristics, and past conversations. These summaries condition the reward model, enabling it to make personalized predictions about the types of responses valued by each user. Both the user-summarization model and reward model are trained simultaneously, creating an online co-adaptation loop. We show that in contrast to the standard Bradley–Terry model, summaries produced by PLUS capture diverse aspects of user preferences, achieving a 11–77\% improvement in reward model accuracy. Key strengths of PLUS are: (1) robust performance with new users and conversation topics, achieving a 25\% improvement over the best personalized reward model technique used for RLHF; (2) zero-shot personalization with state-of-the-art proprietary models like GPT-4 (e.g., PLUS-summary-conditioned responses achieved a 72\% win rate compared to 28\% for default GPT-4o); (3) learning from flexible user contexts beyond preference labels, and (4) interpretable representation of users, enabling greater transparency and user control in pluralistic LLM alignment.

Theory · Reinforcement Learning and Planning

Harsha Kokel, Michael Katz, Kavitha Srinivas, Shirin Sohrabi

We introduce ACPBench Hard, a dataset of generative, open-ended questions which LLM models needs to answer in order to plan. Models that perform well on these tasks could in principle be integrated into a planner or be used directly as a policy. We discuss the complexity of these tasks as well as the complexity of validating the correctness of their answers and present validation algorithms for each task. Equipped with these validators, we test the performance of a variety of models on our tasks and find that for most of these tasks, the performance of even the largest models is still subpar. The models do not possess even the most basic capability of identifying which actions can be performed in a given state. No model outperforms any other on our proposed tasks and, with a few exceptions, all tested language models score below 65\%, indicating that even the current frontier language models as well as so-called reasoning models have a long way to go before they can reliably reason about planning. ACPBench Hard collection is publicly available, see [https://ibm.github.io/ACPBench](https://ibm.github.io/ACPBench).

Applications · Physics

Vladimir Fanaskov, Ivan Oseledets

Discretisation invariance, a recent innovation in scientific machine learning, is a requirement that ensures an architecture can process inputs of different resolutions. In this post, we formally define this property, provide examples, generate datasets, train architectures, and discuss whether discretisation invariance is living up to its promise.

Deep Learning · Algorithms

Juncheng Dong, Yang Yang, Tao Liu, Yang Wang, Feng Qi, VAHID TAROKH, Kaushik Rangadurai, Shuang Yang

The efficiency of GPU kernels is central to the progress of modern AI, yet optimizing them remains a difficult and labor-intensive task due to complex interactions between memory hierarchies, thread scheduling, and hardware-specific characteristics. While recent advances in large language models (LLMs) provide new opportunities for automated code generation, existing approaches largely treat LLMs as single-shot generators or naive refinement tools, limiting their effectiveness in navigating the irregular kernel optimization landscape. We introduce an LLM agentic framework for GPU kernel optimization that systematically explores the design space through multi-agent collaboration, grounded instruction, dynamic context management, and strategic search. This framework mimics the workflow of expert engineers, enabling LLMs to reason about hardware trade-offs, incorporate profiling feedback, and refine kernels iteratively. We evaluate our approach on KernelBench, a benchmark for LLM-based kernel optimization, and demonstrate substantial improvements over baseline agents: our system produces correct solutions where baselines often fail, and achieves kernels with up to 16$\times$ faster runtime performance. These results highlight the potential of agentic LLM frameworks to advance fully automated, scalable GPU kernel optimization.

General Machine Learning · Probabilistic Methods

Guoxuan Xia

This blogpost clarifies the practical usefulness of having a model with calibrated probabilities, something that is not often clearly stated in the calibration literature. We show that a calibrated model can be relied on to estimate average loss/reward, however, good calibration does not mean that a model is useful for per-sample decision making.