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📰 Dev.to · YMori

Articles from Dev.to · YMori · 36 articles · Updated every 3 hours · View all reads

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Moving an NPB Prediction System to BigQuery — BQML and Cloud Run on the Free Tier
Dev.to · YMori 3w ago
Moving an NPB Prediction System to BigQuery — BQML and Cloud Run on the Free Tier
I migrated my Japanese baseball (NPB) prediction system to Google BigQuery, trained BQML models with SQL window functions, and deployed the API to Cloud Run — a
Monitoring the Strait of Hormuz Blockade with Open AIS Data and a Raspberry Pi
Dev.to · YMori 3w ago
Monitoring the Strait of Hormuz Blockade with Open AIS Data and a Raspberry Pi
Building a real-time maritime monitoring system that quantifies the impact of the 2026 Hormuz crisis using free AIS data, Python, and a Raspberry Pi 5.
I Built a WBC Quarterfinal Scouting App with MLB Statcast Data
Dev.to · YMori 1mo ago
I Built a WBC Quarterfinal Scouting App with MLB Statcast Data
A 5-tab Streamlit dashboard analyzing Japan vs Venezuela using pitch-by-pitch MLB Statcast data — no coaching tone, just numbers
Cross-Repo README Sync with GitHub Actions — Push vs Pull Pattern
Dev.to · YMori 1mo ago
Cross-Repo README Sync with GitHub Actions — Push vs Pull Pattern
How to automatically sync stats between GitHub repositories using GitHub Actions, HTML comment markers, and a pull-based architecture that avoids PAT permission
Optimizing Marcel Projection Weights for NPB — Grid Search + Bootstrap Validation
Dev.to · YMori 1mo ago
Optimizing Marcel Projection Weights for NPB — Grid Search + Bootstrap Validation
The conventional Marcel weights (5/4/3) used in npb-prediction aren't optimal for NPB. I ran a 720-combination grid search on 11 years of NPB data and found sta
Can Statcast Data Improve MLB Player Performance Predictions? — Beating Marcel with LightGBM
Dev.to · YMori 1mo ago
Can Statcast Data Improve MLB Player Performance Predictions? — Beating Marcel with LightGBM
I tried to beat the Marcel projection system using MLB Statcast tracking data (exit velocity, barrel rate, Whiff%, Stuff+). Here's what happened: +12.1% improve
Did Adding Stadium Correction Improve My NPB Baseball Predictions? — A Full Backtest Comparison
Dev.to · YMori 1mo ago
Did Adding Stadium Correction Improve My NPB Baseball Predictions? — A Full Backtest Comparison
I added park factor correction to my Marcel+Stan Bayesian NPB standings model. Win MAE didn't change — but here's why that's expected, and what actually improve
I Added Park Factor Correction to My NPB Bayesian Prediction Model — Backtest Validation & 2026 Forecast
Dev.to · YMori 1mo ago
I Added Park Factor Correction to My NPB Bayesian Prediction Model — Backtest Validation & 2026 Forecast
How adding park factor (PF) correction to a Marcel+Stan Bayesian NPB standings simulation affected accuracy across 8 seasons (2018-2025), and the resulting 2026
I Calculated NPB Park Factors for 10 Years — Stadium Renovations Revealed
Dev.to · YMori 1mo ago
I Calculated NPB Park Factors for 10 Years — Stadium Renovations Revealed
Analyzing 8,619 NPB games (2016–2025) to compute park factors for all 12 stadiums, with special focus on how renovation projects (HR terraces, new stadiums) dra
Did Bayesian Projection (Stan/Ridge) Predict the 2021 NPB Last-to-First Upsets?
Dev.to · YMori 1mo ago
Did Bayesian Projection (Stan/Ridge) Predict the 2021 NPB Last-to-First Upsets?
A follow-up to my Marcel analysis: I applied a Bayesian model (Stan/Ridge correction using K%, BB%, BABIP) to the same 2021 Yakult and Orix question — and found
Park Factors, OAA, and Stuff+ in One Line of Python (savant-extras v0.3.2–v0.4.1)
Dev.to · YMori 1mo ago
Park Factors, OAA, and Stuff+ in One Line of Python (savant-extras v0.3.2–v0.4.1)
savant-extras v0.4.2: removed OAA/Outfield Jump/Stuff+ (already in pybaseball). Park factors remain as the unique addition.
Beyond Marcel: Adding Bayesian Regression to NPB Baseball Predictions — A 15-Step Journey
Dev.to · YMori 1mo ago
Beyond Marcel: Adding Bayesian Regression to NPB Baseball Predictions — A 15-Step Journey
How I tried to beat the Marcel projection system for NPB (Japanese pro baseball) using Stan/Ridge regression with K%/BB%/BABIP features, and what I learned abou
Does Exit Velocity Come from the Front Foot? Exploring Driveline Motion Capture Data
Dev.to · YMori 1mo ago
Does Exit Velocity Come from the Front Foot? Exploring Driveline Motion Capture Data
I analyzed 40 hitters using Driveline OpenBiomechanics C3D data and found that front leg mechanics — not bat speed — may be the key differentiator in exit veloc
Last Place to Champions: What Marcel Projection Reveals About 2021 NPB Yakult and Orix
Dev.to · YMori 1mo ago
Last Place to Champions: What Marcel Projection Reveals About 2021 NPB Yakult and Orix
In 2021, both pennant winners came from last place the year before. Using Marcel team projections with roster-verified data, I analyzed why — and found a league
Why Two Pitchers with the Same Arm Speed Differ by 10 mph — A Motion Capture Analysis
Dev.to · YMori 1mo ago
Why Two Pitchers with the Same Arm Speed Differ by 10 mph — A Motion Capture Analysis
I analyzed 61 pro pitchers using Driveline OpenBiomechanics C3D data and found 5 body mechanics factors that explain a 10+ mph gap in pitch speed among pitchers
Annual Auto-Retraining for NPB Baseball Predictions with GitHub Actions
Dev.to · YMori 1mo ago
Annual Auto-Retraining for NPB Baseball Predictions with GitHub Actions
I added CI/CD to my NPB player performance prediction system: joblib model artifacts, annual metrics JSON, a FastAPI /metrics endpoint, and an 8-step GitHub Act
HTTP 200 but Your Streamlit App Is Still Sleeping — Why GET Requests Don't Work and How Playwright Fixes It
Dev.to · YMori 1mo ago
HTTP 200 but Your Streamlit App Is Still Sleeping — Why GET Requests Don't Work and How Playwright Fixes It
Streamlit Community Cloud apps sleep after inactivity. HTTP GET returns 200 with a static HTML shell, but the Python app never starts. Use Playwright to actuall
3D Skeleton Detection from Baseball Motion Capture Data with Driveline C3D
Dev.to · YMori 1mo ago
3D Skeleton Detection from Baseball Motion Capture Data with Driveline C3D
I analyzed pitching and hitting biomechanics using Driveline OpenBiomechanics C3D data, ezc3d, and MediaPipe. Trunk rotation range showed the strongest correlat
Why Marcel Beat LightGBM: Building an NPB Player Performance Prediction System
Dev.to · YMori 1mo ago
Why Marcel Beat LightGBM: Building an NPB Player Performance Prediction System
I built a Japanese professional baseball (NPB) player performance prediction system using Marcel projection, LightGBM/XGBoost, custom wOBA/wRC+ calculation, and
I Built a Python Package for Every Baseball Savant Leaderboard
Dev.to · YMori 1mo ago
I Built a Python Package for Every Baseball Savant Leaderboard
savant-extras now covers 16 Baseball Savant leaderboards that pybaseball doesn't support — Pitch Movement, Catcher Blocking, Basestealing, Timer Infractions, an