Career Profile

I currently work as a Data Scientist / AI Engineer at Samsung SDS, focused on LLM application development, including RAG systems and agentic workflows. Currently employed, and open to new opportunities.

Before joining Samsung SDS, I completed my Ph.D. in Mathematical Sciences at KAIST, where I studied deep neural networks with inter-node dependency and heavy-tailed distributions. I have a solid foundation in probability theory and statistics, which I apply to develop robust AI solutions.

Professional interests:

  • Large language models and their applications, including retrieval-augmented generation (RAG) and AI agents
  • Data analysis, machine learning, and deep neural networks with heavy-tailed behavior
  • Probability theory – infinite and finite exchangeability, random graphs and graph limits

Knowledge & Skills:

  • Theoretical foundations – Probability Theory, Deep Learning, Statistics
  • Core skills – LangChain & LangGraph, FastAPI, PyTorch

Experiences

Senior Engineer

2024 - Present
Samsung SDS, Seoul

Build and deploy LLM-powered applications for enterprise use cases. Design RAG pipelines and agentic workflows with strong emphasis on evaluation, reliability, and safety. Use DevOps tools for CI/CD, deployment, and monitoring in production environments.

  • Developed RAG systems with data ingestion, retrieval, reranking, and prompt orchestration
  • Implemented agent tools and workflows for multi-step reasoning and task automation
  • Built a no-code data analysis tool using a code interpreter for automated exploratory analysis and reporting
  • Established evaluation frameworks for LLM quality, groundedness, and latency
  • Delivered APIs and services using FastAPI, integrating with cloud platforms including Azure and Samsung Cloud Platform

Education

Ph.D. in Mathematical Sciences

2018 - 2024
KAIST

Focused on the theory of deep neural networks with heavy tails and inter-node dependence. Studied limiting behaviors of network initialization and learning dynamics, and their connections to kernel methods.

Keywords: Neural Network Gaussian Process (NNGP), Neural Tangent Kernel (NTK).

Theoretical background in probabilistic tools including stochastic processes, exchangeable structures, concentration inequalities, and random graphs and graph limits.

B.S. in Mathematical Sciences

2013 - 2018
KAIST

Publications

  • Over-parameterised Shallow Neural Networks with Asymmetrical Node Scaling: Global Convergence Guarantees and Feature Learning
  • François Caron, Fadhel Ayed, Paul Jung, Hoil Lee, Juho Lee, and Hongseok Yang
    Transactions on Machine Learning Research
  • Deep neural networks with dependent weights: Gaussian Process mixture limit, heavy tails, sparsity and compressibility
  • Hoil Lee, Fadhel Ayed, Paul Jung, Juho Lee, Hongseok Yang, and François Caron
    Journal of Machine Learning Research 24 (289), 1-78
  • α-Stable convergence of heavy-tailed infinitely-wide neural networks
  • Paul Jung, Hoil Lee, Jiho Lee, and Hongseok Yang
    Advances in Applied Probability 55 (4), 1415-1441

    Skills & Proficiency

    Python

    LangChain & LangGraph

    FastAPI

    PyTorch