collaborators

6 papers

cs.CL2025

One Missing Piece for Open-Source Reasoning Models: A Dataset to Mitigate Cold-Starting Short CoT LLMs in RL

Hyungjoo Chae, Dongjin Kang, Jihyuk Kim +6

With the release of R1, a publicly available large reasoning model (LRM), researchers commonly train new LRMs by training language models on R1's long chain-of-thought (CoT) infere…

cs.LG2025

Rethinking Reward Model Evaluation Through the Lens of Reward Overoptimization

Sunghwan Kim, Dongjin Kang, Taeyoon Kwon +3

Reward models (RMs) play a crucial role in reinforcement learning from human feedback (RLHF), aligning model behavior with human preferences. However, existing benchmarks for rewar…

cs.CL2025

ToolHaystack: Stress-Testing Tool-Augmented Language Models in Realistic Long-Term Interactions

Beong-woo Kwak, Minju Kim, Dongha Lim +5

Large language models (LLMs) have demonstrated strong capabilities in using external tools to address user inquiries. However, most existing evaluations assume tool use in short co…

cs.CL2025

Web-Shepherd: Advancing PRMs for Reinforcing Web Agents

Hyungjoo Chae, Sunghwan Kim, Junhee Cho +18

Web navigation is a unique domain that can automate many repetitive real-life tasks and is challenging as it requires long-horizon sequential decision making beyond typical multimo…

cs.CL2024

Coffee-Gym: An Environment for Evaluating and Improving Natural Language Feedback on Erroneous Code

Hyungjoo Chae, Taeyoon Kwon, Seungjun Moon +7

This paper presents Coffee-Gym, a comprehensive RL environment for training models that provide feedback on code editing. Coffee-Gym includes two major components: (1) Coffee, a da…

cs.LG2024

Evaluating Robustness of Reward Models for Mathematical Reasoning

Sunghwan Kim, Dongjin Kang, Taeyoon Kwon +4

Reward models are key in reinforcement learning from human feedback (RLHF) systems, aligning the model behavior with human preferences. Particularly in the math domain, there have…