Two-Process Sleep Model (2D) — Process S & Process C

Sleep pressure (S)0.30

StateAWAKE

Hours awake0.0 h

Sim timeDay 1, 00:00

😴 Two-Process Sleep Model

Time speed 6× τ_wake — buildup (h) 18.0 τ_sleep — decay (h) 4.5 Circadian amplitude 0.20

Process S (sleep pressure) rises while awake, decays while asleep. Process C (circadian clock) shifts the sleep/wake thresholds on a 24h cycle. Sleep starts when S reaches the upper threshold, ends when S falls to the lower one.