Heajun An

Heajun An

Computer Science Ph.D. Student

I am a second-year Ph.D. student in the Department of Computer Science at Virginia Tech, advised by Professor Jin-Hee Cho. I am a member of the Trustworthy Cyberspace Lab (tClab). My research lies at the intersection of artificial intelligence and cybersecurity, with a focus on reinforcement learning, large language models, and human-centered system design for online safety and security.

Research Interests

Goal-Directed Reinforcement Learning Designing reinforcement learning agents that achieve structured, goal-oriented behavior in complex and interactive environments.

Modular LLM Guardrails and Safety Developing modular and audience-specific guardrails to guide large language model behavior and mitigate harmful or inappropriate outputs.

Human–LLM Interaction Understanding and analyzing how people interact with and utilize LLM-based systems in real-world and educational contexts.

AI for Cybersecurity Education Designing AI-driven approaches for online safety, including scam and cybergrooming prevention.

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