Reliable and efficient video understanding for social good.

Research for social good has always been my first priority, and it will continue to guide my work. I am a Ph.D. candidate in Brain & Cognitive Engineering at Korea University and a student researcher at KIST AI·Robotics.

My early work on sensing applications, including an ultrasonic SLAM helmet for firefighters and indoor drone tracking, shaped my commitment to dependable systems for real-world needs. I now study reliable and efficient video understanding: identifying anomalous behavior, understanding its temporal context, and explaining it with visual evidence.

My work connects video anomaly detection and understanding, adaptive video sampling, action recognition, and vision-language models (VLMs). Through public-safety research at KIST, I work on contextual anomaly detection and behavior analysis for real-world surveillance video.

Recent work includes BUSTER for VLM-guided anomaly detection with adaptive sampling, Where and What for contextual anomaly detection, and Look Closer for action-guided proficiency estimation.

Current focus: why vision-language models hallucinate in video anomaly understanding, and how selective visual verification can make their explanations more faithful.

Research keywords

  • Video understanding
  • Video anomaly detection & understanding
  • Adaptive video sampling
  • Efficient vision-language models
  • VLM hallucination & reliability
  • Temporal & contextual reasoning
  • Action recognition & human motion analysis
  • Video surveillance & public safety

Featured

Research Highlights

Publications

Visit my Google Scholar page for a comprehensive listing.

Figure 1 from Look Closer

Look Closer: Action-Guided Dense Visual Dynamics for Proficiency Estimation

CVPR Workshop 2026 · Accepted

✨ Pitch & Poster Presentation

Deokhyun Ahn, Hyukjin Kim, Jae-Ho Han, Bumsub Ham, Heeseung Choi, Ig-Jae Kim, Haksub Kim

Figure 1 from BUSTER

BUSTER: Adaptive Sampling for VLM-Guided Unsupervised Video Anomaly Detection

BMVC 2026 · Accepted

Deokhyun Ahn, Yonghun Choi, Jae-Ho Han, Ig-Jae Kim, Haksub Kim

Figure 1 from Learning Robust Representations

Learning Robust Representations for Few-Shot Action Recognition with Frame-Level Ambiguities

IEEE Access · Submitted · 2026

Deokhyun Ahn, Yongjin Jo, Ui-Seok Lee, Haesol Park, Jae-Ho Han, Haksub Kim

Figure 9 from Where and What showing low light and crowded scenarios

Where and What: Contextual Dynamics-Aware Anomaly Detection in Surveillance Videos

IEEE Transactions on Image Processing · 2025

🏆 Impact Factor 13.7 · Top 2.2% in Electrical & Electronic Engineering

Deokhyun Ahn, Yongjin Jo, DongBum Kim, Gi Pyo Nam, Jae-Ho Han, Haksub Kim

Figure 1 from the AOD framework paper

A Foundational Research Framework for Real-World Abandoned Object Detection

Expert Systems with Applications · 2025

DongBum Kim, Deokhyun Ahn, Yongjin Jo, Haesol Park, Sangyoun Lee, Haksub Kim

Figure 1 from the passive tracking paper

A Passive Tracking System Based on Geometric Constraints in Adaptive Wireless Sensor Networks

Sensors 18(10), 3276 · 2018

Biao Zhou, Deokhyun Ahn, J. Lee, C. Sun, S. Ahmed, Youngok Kim

Qualitative result from the indoor mapping paper

2D Indoor Map Building Scheme Using Ultrasonic Module

Journal of KICS 41(8) · 2016

Deokhyun Ahn, Nammoon Kim, Ji-Hye Park, Youngok Kim

Experience

Research Intern → Student Researcher

Korea Institute of Science and Technology (KIST) · AI·Robotics Institute, Vision Intelligence Group

Jan 2022 – Present · Seoul

  • Contribute to public-safety video systems and national R&D projects for city-scale CCTV control centers.
  • Study action recognition and contextual anomaly detection in real-world surveillance video, focusing on when and where anomalous behavior occurs.
  • Research VLM-based explanations of anomalous human behavior, adaptive video sampling, and the reliability of video understanding.

Ph.D. Candidate in Brain & Cognitive Engineering

Korea University

Mar 2023 – Present · Expected March 2027 · Seoul

  • Study whether ideas inspired by human cognitive processes can lead to better deep neural networks and new insights into video understanding.
  • Develop systems that use context to reason about interactions, temporal change, and anomalous behavior rather than relying on appearance alone.

Advised by Prof. Jae-Ho Han.

Researcher

The Korea Transport Institute

Oct 2021 – Dec 2021 · Sejong

  • Contributed to autonomous bus development through SLAM, systems for control centers, policy research, and project coordination.

B.Eng. & M.Eng. in Electronic Engineering

Kwangwoon University

Mar 2013 – Feb 2020 · Seoul

  • Worked on SLAM and IoT systems, including ultrasonic SLAM for a wearable helmet that helps firefighters navigate indoor environments where GPS is unavailable. This work sparked my interest in research for social good.
  • Proposed a passive target tracking method based on DNNs for indoor drone tracking in my master's thesis while studying RF signals, systems, and electronic engineering.

Advised by Prof. Youngok Kim.

Awards

2025 AIR Outstanding Research Award · KIST AI·Robotics Institute

2025 Excellent Paper Award · Korea University Graduate School

2024 Outstanding Oral Presentation Award · KIST Academia and Research Convergence Conference