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Kimin Lee

66 accepted papers

2026

Alignment Tampering: How Reinforcement Learning from Human Feedback Is Exploited to Optimize Misaligned Biases

ICML 2026poster

Reinforcement Learning from Human Feedback (RLHF) is the standard method to align Large Language Models (LLMs) with human preferences. In this work, we introduce alignment tampering, a potential vulnerability where the LLM undergoing alignment influences the preference dataset, causing RLHF to ampli…

Cited by 0SourceScholar
2026

DEAS: DEtached value learning with Action Sequence for Scalable Offline RL

ICLR 2026poster

Offline reinforcement learning (RL) presents an attractive paradigm for training intelligent agents without expensive online interactions. However, current approaches still struggle with complex, long-horizon sequential decision making. In this work, we introduce DEtached value learning with Action…

Cited by 0SourceScholar
2026

Entropy-Aware On-Policy Distillation of Language Models

ICML 2026poster

On-policy distillation is a promising approach for transferring knowledge between language models, where a student learns from dense token-level signals along its own trajectories. This framework typically uses reverse KL divergence, encouraging the student to match the teacher's high-confidence pre…

Cited by 0SourceScholar
2026

Improving Motion in Image-to-Video Models via Adaptive Low-Pass Guidance

CVPR 2026

Recent text-to-video (T2V) models have demonstrated strong capabilities in producing high-quality, dynamic videos. To improve the visual controllability, recent works have considered fine-tuning pre-trained T2V models to support image-to-video (I2V) generation. However, such adaptation frequently su

Cited by 0SourcecodeScholar
2026

Learning Multi-View Spatial Reasoning from Cross-View Relations

CVPR 2026

Vision-language models (VLMs) have achieved impressive results on single-view vision tasks, but lack the multi-view spatial reasoning capabilities essential for embodied AI systems to understand 3D environments and manipulate objects across different viewpoints. In this work, we introduce Cross-View

Cited by 0SourceScholar
2026

MobileSafetyBench: Evaluating Safety of Autonomous Agents in Mobile Device Control

AAAI 2026technical

Autonomous agents powered by large language models (LLMs) show promising potential in assistive tasks across various domains, including mobile device control. As these agents interact directly with personal information and device settings, ensuring their safe and reliable behavior is crucial to prev

Cited by 0SourcePDFScholar
2026

Q-Flow: Stable and Expressive Reinforcement Learning with Flow-based Policy

ICML 2026poster

There is growing interest in utilizing flow-based models as decision-making policies in reinforcement learning due to their high expressive capacity. However, effectively leveraging this expressivity for value maximization remains challenging, as naive gradient-based optimization requires backpropag…

Cited by 0SourceScholar
2026

Quality Over Quantity: Demonstration Curation Via Influence Functions for Data-Centric Robot Learning

ICRA 2026poster

Learning from demonstrations has emerged as a promising paradigm for end-to-end robot control, particularly when scaled to diverse and large datasets. However, the quality of demonstration data, often collected through human teleoperation, remains a critical bottleneck for effective data-driven robo…

2026

Unintended Misalignment from Agentic Fine-Tuning: Risks and Mitigation

AAAI 2026technical

Beyond simple text generation, Large Language Models (LLMs) have evolved into agentic systems capable of planning and interacting with external tools to solve complex tasks. This evolution involves fine-tuning LLMs on agent-specific tasks to enhance their proficiency. However, safety concerns are fr

Cited by 0SourcePDFScholar
2025

Automated Filtering of Human Feedback Data for Aligning Text-to-Image Diffusion Models

ICLR 2025poster

Fine-tuning text-to-image diffusion models with human feedback is an effective method for aligning model behavior with human intentions. However, this alignment process often suffers from slow convergence due to the large size and noise present in human feedback datasets. In this work, we propose Fi…

2025

DiffExp: Efficient Exploration in Reward Fine-tuning for Text-to-Image Diffusion Models

AAAI 2025technical

Fine-tuning text-to-image diffusion models to maximize rewards has proven effective for enhancing model performance. However, reward fine-tuning methods often suffer from slow convergence due to online sample generation. Therefore, obtaining diverse samples with strong reward signals is crucial for…

Cited by 0SourcePDFScholar
2025

DiffusionGuard: A Robust Defense Against Malicious Diffusion-based Image Editing

ICLR 2025poster

Recent advances in diffusion models have introduced a new era of text-guided image manipulation, enabling users to create realistic edited images with simple textual prompts. However, there is significant concern about the potential misuse of these methods, especially in creating misleading or harmf…

2025

Enhancing LLM Agent Safety via Causal Influence Prompting

ACL 2025finding

As autonomous agents powered by large language models (LLMs) continue to demonstrate potential across various assistive tasks, ensuring their safe and reliable behavior is crucial for preventing unintended consequences. In this work, we introduce CIP, a novel technique that leverages causal influenc…

2025

Improbable Bigrams Expose Vulnerabilities of Incomplete Tokens in Byte-Level Tokenizers

EMNLP 2025

Tokenization is a crucial step that bridges human-readable text with model-readable discrete tokens. However, recent studies have revealed that tokenizers can be exploited to elicit unwanted model behaviors. In this work, we investigate incomplete tokens, i.e., undecodable tokens with stray bytes re

Cited by 0SourcePDFScholar
2025

Latent Action Pretraining from Videos

ICLR 2025poster

We introduce Latent Action Pretraining for general Action models (LAPA), the first unsupervised method for pretraining Vision-Language-Action (VLA) models without ground-truth robot action labels. Existing Vision-Language-Action models require action labels typically collected by human teleoperators…

Cited by 20SourcePDFScholar
2025

Learning to Contextualize Web Pages for Enhanced Decision Making by LLM Agents

ICLR 2025poster

Recent advances in large language models (LLMs) have led to a growing interest in developing LLM-based agents for automating web tasks. However, these agents often struggle with even simple tasks on real-world websites due to their limited capability to understand and process complex web page struct…

2025

Silent Branding Attack: Trigger-free Data Poisoning Attack on Text-to-Image Diffusion Models

CVPR 2025poster

Text-to-image diffusion models have achieved remarkable success in generating high-quality contents from text prompts. However, their reliance on publicly available data and the growing trend of data sharing for fine-tuning make these models particularly vulnerable to data poisoning attacks. In this…

Cited by 1SourcePDFScholar
2025

Spread Preference Annotation: Direct Preference Judgment for Efficient LLM Alignment

ICLR 2025oral

Aligning large language models (LLMs) with human preferences becomes a key component to obtaining state-of-the-art performance, but it yields a huge cost to construct a large human-annotated preference dataset. To tackle this problem, we propose a new framework, Spread Preference Annotation with dir…

Cited by 5SourcePDFScholar
2025

Subtask-Aware Visual Reward Learning from Segmented Demonstrations

ICLR 2025poster

Reinforcement Learning (RL) agents have demonstrated their potential across various robotic tasks. However, they still heavily rely on human-engineered reward functions, requiring extensive trial-and-error and access to target behavior information, often unavailable in real-world settings. This pape…

Cited by 0SourcePDFScholar
2025

Understanding Impact of Human Feedback via Influence Functions

ACL 2025long

In Reinforcement Learning from Human Feedback (RLHF), it is crucial to learn suitable reward models from human feedback to align large language models (LLMs) with human intentions. However, human feedback can often be noisy, inconsistent, or biased, especially when evaluating complex responses. Such…

2025

What Really Matters in Many-Shot Attacks? An Empirical Study of Long-Context Vulnerabilities in LLMs

ACL 2025long

We investigate long-context vulnerabilities in Large Language Models (LLMs) through Many-Shot Jailbreaking (MSJ). Our experiments utilize context length of up to 128K tokens. Through comprehensive analysis with various many-shot attack settings with different instruction styles, shot density, topic,…

2024

By My Eyes: Grounding Multimodal Large Language Models with Sensor Data via Visual Prompting

EMNLP 2024main

Large language models (LLMs) have demonstrated exceptional abilities across various domains. However, utilizing LLMs for ubiquitous sensing applications remains challenging as existing text-prompt methods show significant performance degradation when handling long sensor data sequences. In this pape…

2024

Confidence-aware Reward Optimization for Fine-tuning Text-to-Image Models

ICLR 2024poster

Fine-tuning text-to-image models with reward functions trained on human feedback data has proven effective for aligning model behavior with human intent. However, excessive optimization with such reward models, which serve as mere proxy objectives, can compromise the performance of fine-tuned models…

2024

Identity Decoupling for Multi-Subject Personalization of Text-to-Image Models

NeurIPS 2024poster

Text-to-image diffusion models have shown remarkable success in generating personalized subjects based on a few reference images. However, current methods often fail when generating multiple subjects simultaneously, resulting in mixed identities with combined attributes from different subjects. In t…

Cited by 12SourcePDFScholar
2024

Margin Matching Preference Optimization: Enhanced Model Alignment with Granular Feedback

EMNLP 2024finding

Large language models (LLMs) fine-tuned with alignment techniques, such as reinforcement learning from human feedback, have been instrumental in developing some of the most capable AI systems to date. Despite their success, existing methods typically rely on simple binary labels, such as those indic…

2024

Promptable Behaviors: Personalizing Multi-Objective Rewards from Human Preferences

CVPR 2024poster

Customizing robotic behaviors to be aligned with diverse human preferences is an underexplored challenge in the field of embodied AI. In this paper we present Promptable Behaviors a novel framework that facilitates efficient personalization of robotic agents to diverse human preferences in complex e…

2023

DPOK: Reinforcement Learning for Fine-tuning Text-to-Image Diffusion Models

NeurIPS 2023poster

Learning from human feedback has been shown to improve text-to-image models. These techniques first learn a reward function that captures what humans care about in the task and then improve the models based on the learned reward function. Even though relatively simple approaches (e.g., rejection sam…

2023

Guide Your Agent with Adaptive Multimodal Rewards

NeurIPS 2023poster

Developing an agent capable of adapting to unseen environments remains a difficult challenge in imitation learning. This work presents Adaptive Return-conditioned Policy (ARP), an efficient framework designed to enhance the agent's generalization ability using natural language task descriptions and…

2023

Multi-View Masked World Models for Visual Robotic Manipulation

ICML 2023poster

Visual robotic manipulation research and applications often use multiple cameras, or views, to better perceive the world. How else can we utilize the richness of multi-view data? In this paper, we investigate how to learn good representations with multi-view data and utilize them for visual robotic…

2023

Preference Transformer: Modeling Human Preferences using Transformers for RL

ICLR 2023poster

Preference-based reinforcement learning (RL) provides a framework to train agents using human preferences between two behaviors. However, preference-based RL has been challenging to scale since it requires a large amount of human feedback to learn a reward function aligned with human intent. In this…

2023

StyleDrop: Text-to-Image Synthesis of Any Style

NeurIPS 2023poster

Pre-trained large text-to-image models synthesize impressive images with an appropriate use of text prompts. However, ambiguities inherent in natural language, and out-of-distribution effects make it hard to synthesize arbitrary image styles, leveraging a specific design pattern, texture or material…

2022

Masked World Models for Visual Control

CoRL 2022poster

Visual model-based reinforcement learning (RL) has the potential to enable sample-efficient robot learning from visual observations. Yet the current approaches typically train a single model end-to-end for learning both visual representations and dynamics, making it difficult to accurately model the…

Cited by 157SourceScholar
2022

Programmatic Modeling and Generation of Real-Time Strategic Soccer Environments for Reinforcement Learning

AAAI 2022technical

The capability of a reinforcement learning (RL) agent heavily depends on the diversity of the learning scenarios generated by the environment. Generation of diverse realistic scenarios is challenging for real-time strategy (RTS) environments. The RTS environments are characterized by intelligent ent…

Cited by 9SourcePDFScholar
2022

Reinforcement Learning with Action-Free Pre-Training from Videos

ICML 2022spotlight

Recent unsupervised pre-training methods have shown to be effective on language and vision domains by learning useful representations for multiple downstream tasks. In this paper, we investigate if such unsupervised pre-training methods can also be effective for vision-based reinforcement learning (…

2022

Reward Uncertainty for Exploration in Preference-based Reinforcement Learning

ICLR 2022poster

Conveying complex objectives to reinforcement learning (RL) agents often requires meticulous reward engineering. Preference-based RL methods are able to learn a more flexible reward model based on human preferences by actively incorporating human feedback, i.e. teacher's preferences between two clip…

Cited by 93SourcePDFScholar
2022

SURF: Semi-supervised Reward Learning with Data Augmentation for Feedback-efficient Preference-based Reinforcement Learning

ICLR 2022poster

Preference-based reinforcement learning (RL) has shown potential for teaching agents to perform the target tasks without a costly, pre-defined reward function by learning the reward with a supervisor’s preference between the two agent behaviors. However, preference-based learning often requires a la…

Cited by 113SourcePDFScholar
2021

B-Pref: Benchmarking Preference-Based Reinforcement Learning

NeurIPS 2021poster

Reinforcement learning (RL) requires access to a reward function that incentivizes the right behavior, but these are notoriously hard to specify for complex tasks. Preference-based RL provides an alternative: learning policies using a teacher's preferences without pre-defined rewards, thus overcomin…

Cited by 134SourcecodeScholar
2021

Decision Transformer: Reinforcement Learning via Sequence Modeling

NeurIPS 2021poster

We introduce a framework that abstracts Reinforcement Learning (RL) as a sequence modeling problem. This allows us to draw upon the simplicity and scalability of the Transformer architecture, and associated advances in language modeling such as GPT-x and BERT. In particular, we present Decision Tran…

2021

Decoupling Representation Learning from Reinforcement Learning

ICML 2021spotlight

In an effort to overcome limitations of reward-driven feature learning in deep reinforcement learning (RL) from images, we propose decoupling representation learning from policy learning. To this end, we introduce a new unsupervised learning (UL) task, called Augmented Temporal Contrast (ATC), which…

2021

Improving Computational Efficiency in Visual Reinforcement Learning via Stored Embeddings

NeurIPS 2021poster

Recent advances in off-policy deep reinforcement learning (RL) have led to impressive success in complex tasks from visual observations. Experience replay improves sample-efficiency by reusing experiences from the past, and convolutional neural networks (CNNs) process high-dimensional inputs effecti…

2021

Improving Transferability of Representations via Augmentation-Aware Self-Supervision

NeurIPS 2021poster

Recent unsupervised representation learning methods have shown to be effective in a range of vision tasks by learning representations invariant to data augmentations such as random cropping and color jittering. However, such invariance could be harmful to downstream tasks if they rely on the charact…

2021

Learning to Sample with Local and Global Contexts in Experience Replay Buffer

ICLR 2021poster

Experience replay, which enables the agents to remember and reuse experience from the past, has played a significant role in the success of off-policy reinforcement learning (RL). To utilize the experience replay efficiently, the existing sampling methods allow selecting out more meaningful experien…

Cited by 26SourcePDFScholar
2021

MASKER: Masked Keyword Regularization for Reliable Text Classification

AAAI 2021technical

Pre-trained language models have achieved state-of-the-art accuracies on various text classification tasks, e.g., sentiment analysis, natural language inference, and semantic textual similarity. However, the reliability of the fine-tuned text classifiers is an often underlooked performance criterion…

2021

Offline-to-Online Reinforcement Learning via Balanced Replay and Pessimistic Q-Ensemble

CoRL 2021poster

Recent advance in deep offline reinforcement learning (RL) has made it possible to train strong robotic agents from offline datasets. However, depending on the quality of the trained agents and the application being considered, it is often desirable to fine-tune such agents via further online intera…

Cited by 239SourcecodeScholar
2021

PEBBLE: Feedback-Efficient Interactive Reinforcement Learning via Relabeling Experience and Unsupervised Pre-training

ICML 2021oral

Conveying complex objectives to reinforcement learning (RL) agents can often be difficult, involving meticulous design of reward functions that are sufficiently informative yet easy enough to provide. Human-in-the-loop RL methods allow practitioners to instead interactively teach agents through tail…

2021

Reinforcement Learning for Sparse-Reward Object-Interaction Tasks in a First-person Simulated 3D Environment

IJCAI 2021poster

Learning how to execute complex tasks involving multiple objects in a 3D world is challenging when there is no ground-truth information about the objects or any demonstration to learn from. When an agent only receives a signal from task-completion, this makes it challenging to learn the object-repr…

Cited by 12SourcePDFScholar
2021

SUNRISE: A Simple Unified Framework for Ensemble Learning in Deep Reinforcement Learning

ICML 2021spotlight

Off-policy deep reinforcement learning (RL) has been successful in a range of challenging domains. However, standard off-policy RL algorithms can suffer from several issues, such as instability in Q-learning and balancing exploration and exploitation. To mitigate these issues, we present SUNRISE, a…

2021

Skill Preferences: Learning to Extract and Execute Robotic Skills from Human Feedback

CoRL 2021poster

A promising approach to solving challenging long-horizon tasks has been to extract behavior priors (skills) by fitting generative models to large offline datasets of demonstrations. However, such generative models inherit the biases of the underlying data and result in poor and unusable skills when…

Cited by 48SourceScholar
2021

State Entropy Maximization with Random Encoders for Efficient Exploration

ICML 2021spotlight

Recent exploration methods have proven to be a recipe for improving sample-efficiency in deep reinforcement learning (RL). However, efficient exploration in high-dimensional observation spaces still remains a challenge. This paper presents Random Encoders for Efficient Exploration (RE3), an explorat…

2021

URLB: Unsupervised Reinforcement Learning Benchmark

NeurIPS 2021poster

Deep Reinforcement Learning (RL) has emerged as a powerful paradigm to solve a range of complex yet specific control tasks. Training generalist agents that can quickly adapt to new tasks remains an outstanding challenge. Recent advances in unsupervised RL have shown that pre-training RL agents with…

Cited by 181SourcecodeScholar
2020

Context-aware Dynamics Model for Generalization in Model-Based Reinforcement Learning

ICML 2020poster

Model-based reinforcement learning (RL) enjoys several benefits, such as data-efficiency and planning, by learning a model of the environment’s dynamics. However, learning a global model that can generalize across different dynamics remains a challenge. To tackle this problem, we decompose the task…

2020

Network Randomization: A Simple Technique for Generalization in Deep Reinforcement Learning

ICLR 2020poster

Deep reinforcement learning (RL) agents often fail to generalize to unseen environments (yet semantically similar to trained agents), particularly when they are trained on high-dimensional state spaces, such as images. In this paper, we propose a simple technique to improve a generalization ability…

Cited by 246SourcecodeScholar
2020

Regularizing Class-Wise Predictions via Self-Knowledge Distillation

CVPR 2020poster

Deep neural networks with millions of parameters may suffer from poor generalization due to overfitting. To mitigate the issue, we propose a new regularization method that penalizes the predictive distribution between similar samples. In particular, we distill the predictive distribution between dif…

Cited by 379PDFcodeScholar
2020

Reinforcement Learning with Augmented Data

NeurIPS 2020spotlight

Learning from visual observations is a fundamental yet challenging problem in Reinforcement Learning (RL). Although algorithmic advances combined with convolutional neural networks have proved to be a recipe for success, current methods are still lacking on two fronts: (a) data-efficiency of learnin…

2020

Trajectory-wise Multiple Choice Learning for Dynamics Generalization in Reinforcement Learning

NeurIPS 2020poster

Model-based reinforcement learning (RL) has shown great potential in various control tasks in terms of both sample-efficiency and final performance. However, learning a generalizable dynamics model robust to changes in dynamics remains a challenge since the target transition dynamics follow a multi-…

2019

Overcoming Catastrophic Forgetting With Unlabeled Data in the Wild

ICCV 2019poster

Lifelong learning with deep neural networks is well-known to suffer from catastrophic forgetting: the performance on previous tasks drastically degrades when learning a new task. To alleviate this effect, we propose to leverage a large stream of unlabeled data easily obtainable in the wild. In parti…

Cited by 285PDFcodeScholar
2019

Robust Inference via Generative Classifiers for Handling Noisy Labels

ICML 2019oral

Large-scale datasets may contain significant proportions of noisy (incorrect) class labels, and it is well-known that modern deep neural networks (DNNs) poorly generalize from such noisy training datasets. To mitigate the issue, we propose a novel inference method, termed Robust Generative classifie…

2018

A Simple Unified Framework for Detecting Out-of-Distribution Samples and Adversarial Attacks

NeurIPS 2018spotlight

Detecting test samples drawn sufficiently far away from the training distribution statistically or adversarially is a fundamental requirement for deploying a good classifier in many real-world machine learning applications. However, deep neural networks with the softmax classifier are known to produ…

2018

Hierarchical Novelty Detection for Visual Object Recognition

CVPR 2018poster

Deep neural networks have achieved impressive success in large-scale visual object recognition tasks with a predefined set of classes. However, recognizing objects of novel classes unseen during training still remains challenging. The problem of detecting such novel classes has been addressed in the…

Cited by 94SourcePDFScholar
2018

Learning to Specialize with Knowledge Distillation for Visual Question Answering

NeurIPS 2018poster

Visual Question Answering (VQA) is a notoriously challenging problem because it involves various heterogeneous tasks defined by questions within a unified framework. Learning specialized models for individual types of tasks is intuitively attracting but surprisingly difficult; it is not straightforw…

2018

Training Confidence-calibrated Classifiers for Detecting Out-of-Distribution Samples

ICLR 2018poster

The problem of detecting whether a test sample is from in-distribution (i.e., training distribution by a classifier) or out-of-distribution sufficiently different from it arises in many real-world machine learning applications. However, the state-of-art deep neural networks are known to be highly ov…