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hjkim720/README.md

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Hi, I'm Hyojoon Kim πŸ‘‹

πŸŽ“ Mathematics Major Β· πŸ’» AI & Data Science Enthusiast Β· πŸ† Competition-driven Learner


πŸŽ“ Education & Bootcamp

  • B.S. Intensive Major in Mathematics
  • SSAFY 13th, Samsung Software/AI Academy for Youth

πŸ’» Tech Stack

Python scikit-learn PyTorch Vue.js Django R MATLAB


πŸ† Competitions & Achievements

πŸ“Š 13th MOTIE Public Data Utilization Idea Contest β€” Grand Prize (Minister of Trade, Industry and Energy Award)
  • Competition Link
  • GitHub Link
  • Role: Team Leader
  • Project: Correction of weather forecast errors caused by the distance between prediction and observation points
  • Goal: Improve day-ahead (24-hour) weather prediction accuracy for industrial sites (solar power, gas turbines), enabling better operational safety and combustion stability
  • Model: Ensemble of XGBoost (capturing structured patterns via GBDT) + MLP (capturing nonlinear & latent patterns)
  • Achievement: Grand Prize (μ‚°μ—…ν†΅μƒμžμ›λΆ€ μž₯관상) for excellence in data utilization and industrial impact
πŸ’³ SSAFY Big Data Project β€” Excellence Award (Samsung Electronics Co., Ltd.)
  • Project: FinCoach - AI-powered financial coaching service (Credit card delinquency prediction & spending pattern improvement recommendation service based on user MyData)
  • Role: DA & DE
  • Duration: 2025.08 ~ 2025.10 | Team of 6 (FE 2, BE 2, Data 2)

Key Achievements:

  • Realistic MyData generation pipeline (DE): Combined AI HUB financial synthetic data + Statistics Korea household survey data, reflecting age-specific spending patterns with individual preference-based diversity using the principle "individuals behave uniquely, groups follow statistics"
  • Credit card delinquency prediction model (ML): HistGradientBoostingClassifier-based model with 46 engineered features (13 personal info + 33 monthly derived variables including early/mid/late-month spending ratios, credit/debit ratios, 7 major category amounts/ratios, average transaction size, weekend/night spending ratios, HHI, entropy, 3-month rolling, EOM prediction, etc.)
  • Spending habit improvement recommendation system: Hybrid CF + CBF approach using cosine similarity to extract top 5% similar users, analyzing 4 comparative perspectives: (1) current month vs similar users (2) 3-month average vs similar users (3) current month vs last month (4) current month vs personal 3-month average
  • FastAPI-based prediction/recommendation API: Developed endpoints for delinquency prediction and spending comparison recommendations with real-time MySQL integration

Tech Stack: Python, scikit-learn, pandas, NumPy, FastAPI, pydantic, MySQL

Acheivement: Excellence Award (μš°μˆ˜μƒ) from Samsung Electronics

🌦 KMA 2025 Weather Data Contest β€” Finalist, Honorable Mention
  • Competition Link
  • Project: Predicted subway congestion levels using time-series weather and observational data
  • Reasoning: Dataset had numerous categorical variables, outliers, and missing values β†’ CatBoost was more effective than specialized time-series models in this case
  • Model: CatBoost (robust for categorical features, missing values, and outliers)
  • Achievement: Finalist & Honorable Mention
🚧 2025 SSAFY AI Challenge (Kaggle, pothole detection) β€” 8th place (Top 3%)
  • Competition Link
  • Role: Team Leader
  • Project: Developed an object detection model to identify potholes using real-world road images
  • Model: YOLOv8
  • Achievement: 8th place (Top 3%)
πŸ–±οΈ Toss NEXT ML CHALLENGE (Dacon, CTR Prediction) β€” Advanced to Final Round
  • Competition Link
  • GitHub Link
  • Role: Team Leader
  • Project: Advertisement Click-Through Rate (CTR) Prediction Model
  • Goal: Predict user ad click probability using user demographics, ad attributes, domain features, and behavioral sequences
  • Model Architecture: Ensemble of two approaches
    • Model 1: CatBoost (base) + Transformer (sequence processing)
    • Model 2: xDeepFM (base) + Attention mechanism (sequence processing)
  • Key Features:
    • Sequence modeling with Transformer encoder for user behavior patterns
    • Deep feature interaction modeling with xDeepFM's Compressed Interaction Network (CIN)
    • Attention-based pooling for sequence aggregation
    • Hybrid ensemble combining tree-based and deep learning approaches
  • Achievement: Advanced to Final Round through effective fusion of tabular and sequential modeling
  • Tech Stack: Python, PyTorch, CatBoost, pandas, NumPy, scikit-learn
πŸš— Hecto AI Challenge (Dacon, 2025 Hecto Recruitment AI Competition) β€” Top 13%
  • Competition Link
  • Role: Team Leader
  • Project: Classified used car types through image-based computer vision modeling
  • Model: Ensemble of Swin Transformer and ConvNeXt
  • Achievement: Top 13%
🏎 2025 SUMMER SSAFY RACE Basic Map β€” 2nd place
  • Role: Team Leader
  • Project: Designed obstacle-avoidance and high-speed driving logic in a virtual autonomous driving environment
  • Achievement: 2nd place
πŸ’‘ 2025 Shinhan Hackathon with SSAFY β€” Final Round
  • Project: Built a 6-month quest-based savings product where users earn EXP by completing Life/Growth/Surprise quests, level up for preferential interest rates, and contribute bonus interest to school-level donation pools
  • My Role:
    • Developed and maintained the recommendation system end-to-end (hybrid CF+CBF with cold-start fallback, FastAPI + SQLAlchemy, interaction logging)
    • Contributed to the app’s front-end by handling design-oriented tasks in React Native (screens, components, styling)
  • Achievement: Final Round (On-site)
πŸ“ 2023 JBNU Science Research Fair β€” Outstanding Presentation Award
  • Study: Endomorphism of the 4-torsion group of elliptic curves
  • Context: Participated as an undergraduate in a graduate-level academic conference
  • Achievement: Outstanding Presentation Award (μš°μˆ˜λ°œν‘œμƒ)

πŸ“ˆ Algorithm Practice

Solved.ac ν”„λ‘œν•„
πŸ”— Algorithm Repository


🌍 Languages

  • English β€” Fluent

    • TOEIC 990 (Acquired 2023.02)
    • OPIC AL (Acquired 2025.09)
    • 1.5 year study abroad & living experience in San Diego, CA
  • Korean β€” Native

  • Spanish β€” Beginner (aprendiendo)


πŸ”₯ Passions & Interests

  • Competing in AI and data science challenges πŸš€
  • Applying mathematical thinking to model optimization
  • Continuous learning & collaborative growth

πŸ“« Contact

Gmail πŸ’‘ Open to collaboration on AI/ML competitions and data challenges β€” feel free to reach out!

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