2023.08 — Present CURRENT
AI Engineer / NLP Engineer
BHSN
Seoul, South Korea
- • Contract review AI system design & development — patented (10-2867168)
- • Legal domain LLM training (SFT/DPO) · serving (vLLM) · evaluation (LLM-as-a-Judge)
- • LangGraph-based workflow/agent platform — 10+ scenarios in production
- • Code → productization → operations → non-developer self-serve structure design
Project Timeline
Technical Deep Dive
LLM Serving Infrastructure
- • PagedAttention-based vLLM — from initial evaluation through K8s production deployment
- • V0→V1 engine migration — 84K-token EPC contracts 478s→100s (4.8x speedup)
- • RadixAttention prefix caching for repetitive contract review patterns
- • LiteLLM multi-model routing for GPU memory efficiency
Long-Context Legal Document Processing
- • 54K-80K token legal contract production pipeline
- • 'Lost in the Middle' position bias — empirical validation in legal domain via Needle-in-a-Haystack
- • Long-context SFT — base Gemma-3 hit rate 0.081→0.383 (approaching GPT-4.1's 0.390)
GPU Infrastructure & Model Training
- • AICA program — A100/H100 GPU resources, outstanding performance recognition
- • 5 task-specific LoRA adapters on Qwen2.5-14B (checklist·edit·translate·extract·Contract-AI)
- • LlamaFactory bug patch — training time 12h→3h (75% reduction)
- • 4 PRs to LoRAX OSS — serving infra behind LoRA Land paper
Structured Output & Guided Decoding
- • JSON schema, regex, FSM guided decoding — contract classification·checklist·drafting
- • response_format policy design across vLLM/LoRAX
- • LoRAX PR #644 — structured output serving interface implementation
Evaluation Metrics System
- • 16+ metrics designed — traditional 6 + G-Eval 5 + contract-split 5
- • Legal expert rubrics codified (policy compliance·revision quality·coherence)
- • GPT-4.1 / Claude Sonnet 4 / custom judge model simultaneous support
- • 10+ model benchmark leaderboard
Responsibilities
Develop NLP/LLM systems for legal and business document processing
Build contract review AI — checklist review, revision suggestions, summarization, SSE streaming
Train legal domain-specific LLMs (SFT/DPO) and manage training datasets
Build and optimize LLM serving infrastructure — vLLM, LoRAX, structured output, long-context
Design and implement AI evaluation metric systems — traditional metrics + LLM-as-a-Judge + human rubrics
Build LangGraph-based workflow/agent platform — 10+ legal task scenarios automated
Develop internal authoring tools for non-developers — prompt, template, workflow asset management UI
Design and implement customer playbook self-serve operational structure
Cross-functional coordination — LegalOps, CLM, Agent Unit, QA, external partners
Key Projects
Contract AI & Review Systems
Core product API covering contract extraction, review, and revision. FastAPI-based SSE streaming, vLLM serving, structured output. 2.5 years in production.
- Checklist v2 human eval 80.41% (GPT-4o 79.16%)
- 38 contract types × 5 languages
- 4 enterprise PoC deployments
- Korea registered patent 10-2867168
- 54K-80K token EPC contract long-context processing
LLM Training & Alignment Pipeline
End-to-end from legal SFT dataset design to SFT/DPO training on A100/H100 GPUs and service deployment.
- Multi-task SFT overall 0.9138 (GPT-4.1 SOTA 0.8731, +4.7%)
- Training time 12h→3h (75% reduction, LlamaFactory bug patch)
- 5 task-specific LoRA adapters on Qwen2.5-14B
- Long-context SFT: hit rate 0.081→0.383 (approaching GPT-4.1's 0.390)
Workflow Platform & Agent Tooling
LangGraph-based workflow engine and agent platform.
- 10+ workflow types in production
- Agent Legal launch — paid workspaces 41→227 (team metric)
- Coding Agent CLI for agentic testing
AI Evaluation & Metrics System
Legal domain-specific evaluation framework combining traditional quantitative metrics + LLM-as-a-Judge + legal expert rubrics.
- 16+ legal AI task metrics designed and implemented (traditional 6 + G-Eval 5 + contract-split 5)
- GPT-4.1 / Claude Sonnet 4 / custom judge model simultaneous support
- 10+ model simultaneous benchmark leaderboard
- Model ensemble + human review gold standard dataset
OSS: predibase/lorax
4 PRs merged into LoRAX — a production implementation of S-LoRA (MLSys 2024) and Punica (MLSys 2024) multi-LoRA serving research.
- Contributed 2024-03 ~ 2024-10, Rust/Python
- Directly contributed to LoRA Land paper's (310 models evaluated) serving infrastructure
- Internal fork → K8s production serving
- Structured output (PR #644) → internal contract classification/checklist pipeline
Achievements
- Korea registered patent 10-2867168, co-inventor (2025-09-26) ↗
- LangCon 2024 talk: Open Model Long Context Tuning ↗
- Build with AI for Everyone talk: Structured Output Deterministic LLM ↗
- allibee tech blog: Reasoning Legal AI ↗
- allibee tech blog: RoPE/NoPE for Long-Context Documents ↗
- Hankook Ilbo interview: Evolving AI Engineers ↗
Skills Demonstrated
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