ML Pipeline Construction• Converted Scala-based MF model to Python-based ML model• Designed and developed Python framework structure (Python, PyTorch)• Built model training/experimentation environment on NVIDIA HGX A100 servers (Argo Workflows, JupyterHub)Inference-Dedicated Server Cluster Setup• Built inference-dedicated server cluster to separate model inference from recommendation API with business logic• Constructed TorchServe cluster on AWS EKS (CPU-only… Show more ML Pipeline Construction• Converted Scala-based MF model to Python-based ML model• Designed and developed Python framework structure (Python, PyTorch)• Built model training/experimentation environment on NVIDIA HGX A100 servers (Argo Workflows, JupyterHub)Inference-Dedicated Server Cluster Setup• Built inference-dedicated server cluster to separate model inference from recommendation API with business logic• Constructed TorchServe cluster on AWS EKS (CPU-only mode)• Changed communication data format from JSON to msgpack, improving communication speed by 30%• Packaged code to enable reuse of model training code in TorchServe inference handlersRecommendation API Development, Monitoring, and Deployment Automation• Developed recommendation API for service servers (Scala)• Created dashboard for recommendation KPI monitoring (Google Looker Studio)• Implemented API server performance tracking (Datadog)• Established and operated CI/CD for stable recommendation server operation (Jenkins - Configuration as Code, Pipeline as Code)Friend Recommendation Model Development using LightGCN• Replaced computationally expensive MF-based taste matching score friend recommendation with ML model-based friend recommendation• Enabled more diverse user recommendations due to relationship-based approachData Analysis Team Building and Leadership• Established data analysis team, set team agendas, recruitment, and management• Developed KPIs and dashboards using Google Looker Studio• Operated team to focus on data analysis for product development, content acquisition, and IR/PR needs, reporting Show less

Product search ranking development (Learning to Rank)• Built data pipeline for search indexing• Solely responsible for EDA, feature selection, and feature extraction for model development• Exclusively developed learning data labeling tools and model evaluation tools

E-commerce service development• Developed web/mobile smartwatch shopping service• Built product and customer management web admin

E-commerce service development• Improved development team culture (introduced Agile methodology, project management,retrospectives)• Designed service architecture, developed API server/admin, and set up search server

Search spam filter system development• Developed spam detection model for various documents (Naive Bayesian probability model)• Built model training data pipeline• Developed in-house API for providing spam detection data• Solely responsible for developing JavaScript-based web document spam filter

E-commerce site development• Developed Coupang web frontend main page• Developed product exposure admin system

High-performance HTTP server development• Developed high-performance HTTP server for production services (C/C++)• Implemented thread-based event processing method to solve C10K problemBoolean search system development• Developed low-cost, high-efficiency search engine• Applied to Mail (35M-user) and Blog (15M-user) services• Responsible for developing indexing server, search API server, and MQ serverVirtualization service development• Developed… Show more High-performance HTTP server development• Developed high-performance HTTP server for production services (C/C++)• Implemented thread-based event processing method to solve C10K problemBoolean search system development• Developed low-cost, high-efficiency search engine• Applied to Mail (35M-user) and Blog (15M-user) services• Responsible for developing indexing server, search API server, and MQ serverVirtualization service development• Developed virtualization service to support project piloting for various development roles• Provided both Linux and Windows virtualization environments• Solely responsible for system design, construction, and developmentDeployment history and source management system development• Developed system to address issues arising from lack of service deployment history management• Developed integrated operation and management tools for previously scattered in-house sourcemanagement systems• Conducted usage training for internal development teams Show less

E-commerce platform development• Developed video sharing service for product introductions within each shopping mall (similar toYouTube)• Solely responsible for developing video player and transcoder