WonSeok Lee

Backend Engineer

a backend engineer building data platforms and AI automation

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About me

Parallel & High-Volume Architecture

Designing systems that stay fast and correct under heavy load.

Kafka · thread-based parallel processing
Concurrency control & bottleneck analysis

Data Platforms & Integrity

Moving and validating large-scale data without losing trust in it.

Large-scale migration & multi-stage validation
Oracle-based data operations

Applied AI · RAG

Turning LLMs into reliable, grounded business tools.

Hybrid retrieval (dense + lexical) with Qdrant
Prompt design for hallucination control

Problem Structuring & Leadership

Turning tacit business knowledge into systems teams can run.

Requirement discovery with business teams
Standards, guides & team enablement

Career

4Y 3M

POSCO DX

Full-time
Jun 2022 – Present4Y 3M

SCM Operations (Backend, Frontend)

Jun 2022 – Jan 20241 member
LLMJavaScriptJavaOracle

Marketing DX Refresh — Sub PL, Backend Development

Jan 2024 – Dec 202543 members
OracleKafkaJavaJavaScript

SCM Software · AX Development & Operations (Backend, Frontend)

Jan 2026 – Present1 member
OracleQdrantGemini EnterpriseJavaJavaScriptLLM

Bit Training Center

Team Lead
Dec 2021 – May 20226 months

Java Expert Program

Dec 2021 – May 2022

Certifications

01

Big Data Analytics Engineer

Korea Data Agency
Dec 2022
02

ADsP — Advanced Data Analytics Semi-Professional

Korea Data Agency
Dec 2021
03

Engineer Information Processing

Human Resources Development Service of Korea
Jun 2021

Awards

Karma — Unity 3D Game

Jeonbuk National University
Game Development Contest — Excellence AwardDec 2020
Project Exhibition — Bronze AwardNov 2020

Led a 3-person team building the core gameplay systems (movement, NPC interaction, quests, UI events) in C#, and designed a real-time Raycast/Collider-based interaction system.

Designed the system architecture: reusable component-based common features via prefabs, with event-driven object interaction logic.

Gameplay demo