Yoshimitsu Systems · Engineering NotesSourced, reproducible technical notes, each with code you can run.https://www.yoshimitsu-systems.com/notes/2026-10-19T00:00:00ZYoshimitsu Systems EngineeringTomorrow's air: a dilated CNN against the forecasts it has to beathttps://www.yoshimitsu-systems.com/notes/ys-en-0006-dilated-cnn-day-ahead-co2.html2026-10-19T00:00:00Z2026-10-19T00:00:00ZMorimoto KenjiCan a WaveNet-style dilated causal CNN forecast tomorrow's office CO2 from last week's readings? Tested against seven no-training baselines, linear models and a GRU on 13 real offices, with holidays held out. It works, mostly on empty days, a GRU does better, and the calendar matters more than the network. With code.What a 40-year MTBF actually promises, checked against real failure datahttps://www.yoshimitsu-systems.com/notes/ys-en-0005-what-a-40-year-mtbf-promises.html2026-10-06T00:00:00Z2026-10-06T00:00:00ZDeclan LebowskiMTBF is a rate, not a lifetime. What a 40-year MTBF promises for a fleet, how vendors arrive at the number, and what 13 years of Backblaze data on half a million hard drives shows about the constant-rate assumption behind it. With code.Spares for a one-way triphttps://www.yoshimitsu-systems.com/notes/ys-en-0004-spares-for-a-one-way-trip.html2026-10-05T00:00:00Z2026-10-05T00:00:00ZDeclan LebowskiHow many spare parts 225 compute cores need for a 40-year trip with no resupply: Poisson sparing, spare modules versus spare cores, k-of-n tolerance, and why an uncertain failure rate costs more than bad luck. With a calculator and code.What the benchmark threw away: classifying variable stars without their periodshttps://www.yoshimitsu-systems.com/notes/ys-en-0003-light-curves-without-periods.html2026-08-05T00:00:00Z2026-10-04T00:00:00ZTakeda AoiPretrained image models on pictures of light curves against MiniROCKET and HIVE-COTE 2 on StarLightCurves, a fair head-to-head, and an OGLE-IV rebuild of the dataset that keeps each star's period to measure what the period is worth.Navigating by parallax: how New Horizons found itself among the starshttps://www.yoshimitsu-systems.com/notes/ys-en-0002-navigating-by-parallax.html2026-06-05T00:00:00Z2026-10-03T00:00:00ZTakeda AoiTwo stars, one camera, 47 au from home: the first interstellar navigation fix, reproduced from Gaia DR3, with the geometry, the error budget, the best reference stars, and code you can run.Homa vs TCP: the transport that sends the shortest message firsthttps://www.yoshimitsu-systems.com/notes/ys-en-0001-homa-tcp-replacement.html2026-04-05T00:00:00Z2026-10-03T00:00:00ZDeclan LebowskiWhy scheduling the shortest message first beats fair sharing, what Homa measured against TCP on real hardware, what is still unsolved, and where Linux upstreaming stands in 2026. With a simulation you can run.