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Jongwook Choi

16 accepted papers

2025

Beyond Spatial Frequency: Pixel-wise Temporal Frequency-based Deepfake Video Detection

ICCV 2025poster

We introduce a deepfake video detection approach that exploits pixel-wise temporal inconsistencies, which traditional spatial frequency-based detectors often overlook. The traditional detectors represent temporal information merely by stacking spatial frequency spectra across frames, resulting in th…

2025

Interactive and Expressive Code-Augmented Planning with Large Language Models

ACL 2025long

Large Language Models (LLMs) demonstrate strong abilities in common-sense reasoning and interactive decision-making, but often struggle with complex, long-horizon planning tasks. Recent techniques have sought to structure LLM outputs using control flow and code to improve planning performance. Howev…

Cited by 0SourcePDFScholar
2024

Exploiting Style Latent Flows for Generalizing Deepfake Video Detection

CVPR 2024poster

This paper presents a new approach for the detection of fake videos based on the analysis of style latent vectors and their abnormal behavior in temporal changes in the generated videos. We discovered that the generated facial videos suffer from the temporal distinctiveness in the temporal changes o…

Cited by 34SourcePDFScholar
2024

Unsupervised Object Interaction Learning with Counterfactual Dynamics Models

AAAI 2024technical

We present COIL (Counterfactual Object Interaction Learning), a novel way of learning skills of object interactions on entity-centric environments. The goal is to learn primitive behaviors that can induce interactions without external reward or any supervision. Existing skill discovery methods are l…

Cited by 6SourcePDFScholar
2022

Fast inference and transfer of compositional task structures for few-shot task generalization

UAI 2022poster

We tackle real-world problems with complex structures beyond the pixel-based game or simulator. We formulate it as a few-shot reinforcement learning problem where a task is characterized by a subtask graph that defines a set of subtasks and their dependencies that are unknown to the agent. Different…

Cited by 0SourcePDFScholar
2022

Lipschitz-constrained Unsupervised Skill Discovery

ICLR 2022poster

We study the problem of unsupervised skill discovery, whose goal is to learn a set of diverse and useful skills with no external reward. There have been a number of skill discovery methods based on maximizing the mutual information (MI) between skills and states. However, we point out that their MI…

Cited by 72SourcePDFScholar
2021

Environment Generation for Zero-Shot Compositional Reinforcement Learning

NeurIPS 2021poster

Many real-world problems are compositional – solving them requires completing interdependent sub-tasks, either in series or in parallel, that can be represented as a dependency graph. Deep reinforcement learning (RL) agents often struggle to learn such complex tasks due to the long time horizons and…

2021

Shortest-Path Constrained Reinforcement Learning for Sparse Reward Tasks

ICML 2021spotlight

We propose the k-Shortest-Path (k-SP) constraint: a novel constraint on the agent’s trajectory that improves the sample efficiency in sparse-reward MDPs. We show that any optimal policy necessarily satisfies the k-SP constraint. Notably, the k-SP constraint prevents the policy from exploring state-a…

2021

Successor Feature Landmarks for Long-Horizon Goal-Conditioned Reinforcement Learning

NeurIPS 2021poster

Operating in the real-world often requires agents to learn about a complex environment and apply this understanding to achieve a breadth of goals. This problem, known as goal-conditioned reinforcement learning (GCRL), becomes especially challenging for long-horizon goals. Current methods have tackle…

Cited by 42SourcePDFScholar
2021

Variational Empowerment as Representation Learning for Goal-Conditioned Reinforcement Learning

ICML 2021spotlight

Learning to reach goal states and learning diverse skills through mutual information maximization have been proposed as principled frameworks for unsupervised reinforcement learning, allowing agents to acquire broadly applicable multi-task policies with minimal reward engineering. In this paper, we…

Cited by 40SourcePDFScholar
2020

Memory Based Trajectory-conditioned Policies for Learning from Sparse Rewards

NeurIPS 2020poster

Reinforcement learning with sparse rewards is challenging because an agent can rarely obtain non-zero rewards and hence, gradient-based optimization of parameterized policies can be incremental and slow. Recent work demonstrated that using a memory buffer of previous successful trajectories can resu…

Cited by 39SourcePDFScholar
2020

Meta Reinforcement Learning with Autonomous Inference of Subtask Dependencies

ICLR 2020poster

We propose and address a novel few-shot RL problem, where a task is characterized by a subtask graph which describes a set of subtasks and their dependencies that are unknown to the agent. The agent needs to quickly adapt to the task over few episodes during adaptation phase to maximize the return i…

Cited by 58SourcecodeScholar
2019

Contingency-Aware Exploration in Reinforcement Learning

ICLR 2019poster

This paper investigates whether learning contingency-awareness and controllable aspects of an environment can lead to better exploration in reinforcement learning. To investigate this question, we consider an instantiation of this hypothesis evaluated on the Arcade Learning Element (ALE). In this st…

Cited by 96SourcePDFScholar
2018

Inferring Semantic Layout for Hierarchical Text-to-Image Synthesis

CVPR 2018poster

We propose a novel hierarchical approach for text-to-image synthesis by inferring semantic layout. Instead of learning a direct mapping from text to image, our algorithm decomposes the generation process into multiple steps, in which it first constructs a semantic layout from the text by the layout…

Cited by 606SourcePDFScholar
2017

End-To-End Concept Word Detection for Video Captioning, Retrieval, and Question Answering

CVPR 2017spotlight

We propose a high-level concept word detector that can be integrated with any video-to-language models. It takes a video as input and generates a list of concept words as useful semantic priors for language generation models. The proposed word detector has two important properties. First, it does no…

Cited by 273PDFScholar
2017

Supervising Neural Attention Models for Video Captioning by Human Gaze Data

CVPR 2017poster

The attention mechanisms in deep neural networks are inspired by human's attention that sequentially focuses on the most relevant parts of the information over time to generate prediction output. The attention parameters in those models are implicitly trained in an end-to-end manner, yet there have…

Cited by 91PDFScholar