Jeehyun Lee


2025

pdf bib
AMAN: Agent for Mentoring and Assisting Newbies in MMORPG
Jeehyun Lee | Seung-Moo Yang | Won Ik Cho
Proceedings of the 31st International Conference on Computational Linguistics: Industry Track

In online games with diverse contents and frequent updates, newcomers first learn gameplay mechanics by community intelligence but soon face challenges that require real-time guidance from senior gamers. To provide easy access to such support, we introduce AMAN, Agent for Mentoring and Assisting Newbies in MMORPG (Massively Multiplayer Online Role-Playing Game) - a companion chatbot designed to engage novice gamers. Our model functions as a human-like chat buddy that interacts with users in a friendly manner while providing substantive informational depth. In this light, we propose a multi-stage learning approach that incorporates continual pre-training with a sequence of online resources and instruction tuning on curated dialogues. To align with gamers’ specific needs, we first analyze user-oriented topics from online communities regarding a widely played MMORPG and construct a domain-specific dataset. Furthermore, we develop a multi-turn dialogue data to foster dynamic conversations with users. The evaluation result with the model trained upon publicly available language model shows our practical applicability on how conversational assistant in online games can help novice gamers.

2024

pdf bib
Chamain: Harmonizing Character Persona Integrity with Domain-Adaptive Knowledge in Dialogue Generation
Seung-Moo Yang | Jeehyun Lee | Won Ik Cho
Proceedings of the 6th Workshop on NLP for Conversational AI (NLP4ConvAI 2024)

Recent advances in large language models (LLMs) have shown their capacity for generating natural dialogues, leveraging extensive pre-trained knowledge. However, the seamless integration of domain-specific knowledge into dialogue agents, without undermining their personas or unique textual style, remains a challenging task. Traditional approaches, such as constructing knowledge-aware character dialogue datasets or training LLMs from the ground up, require considerable resources. Sequentially fine-tuning character chatbots across multiple datasets or applying existing merging techniques often leads to catastrophic forgetting, resulting in the loss of both knowledge and the character’s distinct persona. This compromises the model’s ability to consistently generate character-driven dialogues within a user-centric framework. In this context, we introduce a novel model merging method, Chamain, which effortlessly enhances the performance of character models, much like finding a “free lunch”. Chamain merges domain-specific knowledge into a character model by parameter-wise weight combination of instruction-tuned models and learns to reflect persona’s unique characteristics and style through Layer-wise merging. Our experiments demonstrate that Chamain effectively maintains style while also solving domain-specific problems to a certain extent compared to the baselines, even showing a higher style probability compared to the character model in legal QA.

2023

pdf bib
Enhancing Task-Oriented Dialog System with Subjective Knowledge: A Large Language Model-based Data Augmentation Framework
Haein Jung | Heuiyeen Yeen | Jeehyun Lee | Minju Kim | Namo Bang | Myoung-Wan Koo
Proceedings of The Eleventh Dialog System Technology Challenge

As Task-Oriented Dialog (TOD) systems have advanced, structured DB systems, which aim to collect relevant knowledge for answering user’s questions, have also progressed. Despite these advancements, these methods face challenges when dealing with subjective questions from users. To overcome this, DSTC11 released a subjective-knowledge-based TOD (SK-TOD) dataset and benchmark. This paper introduces a framework that effectively solves SK-TOD tasks by leveraging a Large Language Model (LLM). We demonstrate the proficient use of LLM for each sub-task, including an adapters-based method and knowledge-grounded data augmentation. Our proposed methods, which utilize LLM as an efficient tool, outperform baseline performance and approaches that directly use LLM as a one-step sub-task solver, showing superior task-specific optimization.

pdf bib
Task-Optimized Adapters for an End-to-End Task-Oriented Dialogue System
Namo Bang | Jeehyun Lee | Myoung-Wan Koo
Findings of the Association for Computational Linguistics: ACL 2023

Task-Oriented Dialogue (TOD) systems are designed to carry out specific tasks by tracking dialogue states and generating appropriate responses to help users achieve defined goals. Recently, end-to-end dialogue models pre-trained based on large datasets have shown promising performance in the conversational system. However, they share the same parameters to train tasks of the dialogue system (NLU, DST, NLG), so debugging each task is challenging. Also, they require a lot of effort to fine-tune large parameters to create a task-oriented chatbot, making it difficult for non-experts to handle. Therefore, we intend to train relatively lightweight and fast models compared to PLM. In this paper, we propose an End-to-end TOD system with Task-Optimized Adapters which learn independently per task, adding only small number of parameters after fixed layers of pre-trained network. We also enhance the performance of the DST and NLG modules through reinforcement learning, overcoming the learning curve that has lacked at the adapter learning and enabling the natural and consistent response generation that is appropriate for the goal. Our method is a model-agnostic approach and does not require prompt-tuning as only input data without a prompt. As results of the experiment, our method shows competitive performance on the MultiWOZ benchmark compared to the existing end-to-end models. In particular, we attain state-of-the-art performance on the DST task of 2.2 dataset.