GUARD

A Hierarchical Deep Reinforcement Learning Chatbot for Cybergrooming Prevention.

Overall research structure
Overall research structure.

Full Description

Cybergrooming poses an increasing risk to young internet users, necessitating proactive, AI-driven interventions. This work introduces an adaptive chatbot GUARD that enhances teenagers' resilience against cyber-grooming through dynamic, human-like interactions tailored to individual vulnerability levels.

The system integrates a large language model—fine-tuned on a stage-tagged PJ dataset—with hierarchical deep reinforcement learning to enable flexible transitions across six grooming stages via both reward and context-based signals. A master policy determines the current stage based on conversational cues, while six stage-specific sub-policies optimize responses by leveraging user sentiment and sub-goal achievement.

Performance is evaluated via simulated interactions to ensure the quality of the chatbot prior to deployment. Ultimately, this research provides an AI-driven tool for enhancing online safety education and preventing cybergrooming.

Figures

Publications

In Preparation

Authors: Heajun An, Qi Zhang, Minqian Liu, Xinyi Zhang, Sangwook Lee, Dilruba Showkat, Prakriti Dumaru, Sang Won Lee, Lifu Hwang, Pamela Wisniewski, Jin-Hee Cho

Presentations

ACM CAPWIC 2025 – Student Research Short Talk

Presented "GUARD: A Hierarchical Deep Reinforcement Learning Chatbot for Cybergrooming Prevention" at ACM CAPWIC 2025, March 2025. Slides

CCI Student Researcher Showcase 2025 – Poster Presentation

Presented "GUARD: Grooming Understanding and Action via Reinforcement-based Defense" at the CCI Student Researcher Showcase, Virginia Tech, April 2025 Poster

← Back to Projects