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Insup Lee

27 accepted papers

2026

Conformal Constrained Policy Optimization for Cost-Effective LLM Agents

AAAI 2026technical

While large language models (LLMs) have recently made tremendous progress towards solving challenging AI problems, they have done so at increasingly steep computational and API costs. We propose a novel strategy where we combine multiple LLM models with varying cost/accuracy tradeoffs in an agentic

Cited by 0SourcePDFScholar
2026

Quantifying and Improving Adaptivity in Conformal Prediction Through Input Transformations

AAAI 2026technical

Conformal prediction constructs a set of labels instead of a single point prediction, while providing a probabilistic coverage guarantee. Beyond the coverage guarantee, adaptiveness to example difficulty is an important property. It means that the method should produce larger prediction sets for mor

Cited by 0SourcePDFScholar
2025

Assessing Modality Bias in Video Question Answering Benchmarks with Multimodal Large Language Models

AAAI 2025technical

Multimodal large language models (MLLMs) can simultaneously process visual, textual, and auditory data, capturing insights that complement human analysis. However, existing video question-answering (VidQA) benchmarks and datasets often exhibit a bias toward a single modality, despite the goal of re…

Cited by 2SourcePDFScholar
2025

MrGuard: A Multilingual Reasoning Guardrail for Universal LLM Safety

EMNLP 2025

Large Language Models (LLMs) are susceptible to adversarial attacks such as jailbreaking, which can elicit harmful or unsafe behaviors. This vulnerability is exacerbated in multilingual settings, where multilingual safety-aligned data is often limited. Thus, developing a guardrail capable of detecti

2025

REGENT: A Retrieval-Augmented Generalist Agent That Can Act In-Context in New Environments

ICLR 2025oral

Building generalist agents that can rapidly adapt to new environments is a key challenge for deploying AI in the digital and real worlds. Is scaling current agent architectures the most effective way to build generalist agents? We propose a novel approach to pre-train relatively small policies on re…

Cited by 1SourcePDFScholar
2025

RICL: Adding In-Context Adaptability to Pre-Trained Vision-Language-Action Models

CoRL 2025poster

Multi-task ``vision-language-action'' (VLA) models have recently demonstrated increasing promise as generalist foundation models for robotics, achieving non-trivial performance out of the box on new tasks in new environments. However, for such models to be truly useful, an end user must have easy me…

Cited by 0SourceScholar
2024

AR-Pro: Counterfactual Explanations for Anomaly Repair with Formal Properties

NeurIPS 2024poster

Anomaly detection is widely used for identifying critical errors and suspicious behaviors, but current methods lack interpretability. We leverage common properties of existing methods and recent advances in generative models to introduce counterfactual explanations for anomaly detection. Given an in…

2024

Conformal Prediction Regions for Time Series Using Linear Complementarity Programming

AAAI 2024technical

Conformal prediction is a statistical tool for producing prediction regions of machine learning models that are valid with high probability. However, applying conformal prediction to time series data leads to conservative prediction regions. In fact, to obtain prediction regions over T time steps…

2024

Memory-Consistent Neural Networks for Imitation Learning

ICLR 2024poster

Imitation learning considerably simplifies policy synthesis compared to alternative approaches by exploiting access to expert demonstrations. For such imitation policies, errors away from the training samples are particularly critical. Even rare slip-ups in the policy action outputs can compound qui…

Cited by 11SourcePDFScholar
2024

PAC Prediction Sets Under Label Shift

ICLR 2024poster

Prediction sets capture uncertainty by predicting sets of labels rather than individual labels, enabling downstream decisions to conservatively account for all plausible outcomes. Conformal inference algorithms construct prediction sets guaranteed to contain the true label with high probability. The…

2024

TRAQ: Trustworthy Retrieval Augmented Question Answering via Conformal Prediction

NAACL 2024long

When applied to open-domain question answering, large language models (LLMs) frequently generate incorrect responses based on made-up facts, which are called hallucinations. Retrieval augmented generation (RAG) is a promising strategy to avoid hallucinations, but it does not provide guarantees on it…

2024

Uncertainty in Language Models: Assessment through Rank-Calibration

EMNLP 2024main

Language Models (LMs) have shown promising performance in natural language generation. However, as LMs often generate incorrect or hallucinated responses, it is crucial to correctly quantify their uncertainty in responding to given inputs. In addition to verbalized confidence elicited via prompting,…

2023

Angelic Patches for Improving Third-Party Object Detector Performance

CVPR 2023poster

Deep learning models have shown extreme vulnerability to simple perturbations and spatial transformations. In this work, we explore whether we can adopt the characteristics of adversarial attack methods to help improve perturbation robustness for object detection. We study a class of realistic objec…

2023

Bootstrapping Small \& High Performance Language Models with Unmasking-Removal Training Policy

EMNLP 2023short main

BabyBERTa, a language model trained on small-scale child-directed speech while none of the words are unmasked during training, has been shown to achieve a level of grammaticality comparable to that of RoBERTa-base, which is trained on 6,000 times more words and 15 times more parameters. Relying on t…

Cited by 0SourceScholar
2022

Exploring with Sticky Mittens: Reinforcement Learning with Expert Interventions via Option Templates

CoRL 2022poster

Long horizon robot learning tasks with sparse rewards pose a significant challenge for current reinforcement learning algorithms. A key feature enabling humans to learn challenging control tasks is that they often receive expert intervention that enables them to understand the high-level structure o…

Cited by 4SourcecodeScholar
2022

Learning Enabled Fast Planning and Control in Dynamic Environments with Intermittent Information

IROS 2022poster

This paper addresses a safe planning and control problem for mobile robots operating in communication- and sensor-limited dynamic environments. In this case the robots cannot sense the objects around them and must instead rely on intermittent, external information about the environment, as e.g., in…

Cited by 1SourceScholar
2022

Sequential Covariate Shift Detection Using Classifier Two-Sample Tests

ICML 2022spotlight

A standard assumption in supervised learning is that the training data and test data are from the same distribution. However, this assumption often fails to hold in practice, which can cause the learned model to perform poorly. We consider the problem of detecting covariate shift, where the covariat…

2022

iDECODe: In-Distribution Equivariance for Conformal Out-of-Distribution Detection

AAAI 2022technical

Machine learning methods such as deep neural networks (DNNs), despite their success across different domains, are known to often generate incorrect predictions with high confidence on inputs outside their training distribution. The deployment of DNNs in safety-critical domains requires detection of…

2021

Improving Classifier Confidence using Lossy Label-Invariant Transformations

AISTATS 2021poster

Providing reliable model uncertainty estimates is imperative to enabling robust decision making by autonomous agents and humans alike. While recently there have been significant advances in confidence calibration for trained models, examples with poor calibration persist in most calibrated models. C…

Cited by 10SourcePDFScholar
2020

Calibrated Prediction with Covariate Shift via Unsupervised Domain Adaptation

AISTATS 2020poster

Reliable uncertainty estimates are an important tool for helping autonomous agents or human decision makers understand and lever-age predictive models. However, existing approaches to estimating uncertainty largely ignore the possibility of covariate shift—i.e.,where the real-world data distribution…

Cited by 68SourcePDFScholar
2020

PAC Confidence Sets for Deep Neural Networks via Calibrated Prediction

ICLR 2020poster

We propose an algorithm combining calibrated prediction and generalization bounds from learning theory to construct confidence sets for deep neural networks with PAC guarantees---i.e., the confidence set for a given input contains the true label with high probability. We demonstrate how our approach…

Cited by 76SourcecodeScholar
2016

Online planning for energy-efficient and disturbance-aware UAV operations

IROS 2016poster

In this paper we consider an online planning problem for unmanned aerial vehicle (UAV) operations. Specifically, a UAV has the task of reaching a goal from a set of possible goals while minimizing the amount of energy required. Due to unforeseen disturbances, it is possible that initially attractive…

Cited by 62SourceScholar