An algorithm developed over three years by a small team of mathematicians doesn’t just tell users how long they slept. It actually recommends the best time for users to go to bed.
Unlike most sleep features that focus only on the past (“You slept six hours last night”), this algorithm looks ahead. Using mathematical models and the body’s circadian rhythm, it suggests a personalized “sleep window”—like “Going to bed between 11:10 PM and 11:40 PM is ideal for you tonight.”
“It’s kind of like a weather forecast,” says mathematical biologist Jae Kyoung Kim, PhD, a professor at the Korea Advanced Institute for Science and Technology (KAIST) and the Institute for Basic Science, and leader of the team that developed the algorithm, in a release. “Instead of just telling you what happened yesterday, it helps you prepare for tomorrow—so you can sleep better and feel better.”
“We faced a lot of challenges trying to turn our research into a real product,” Kim continues. “People kept asking us when they could try the algorithm, and we always felt bad that we couldn’t release it properly. Now, thanks to the support of KAIST’s Technology Commercialization Center and our partnership with Samsung, our work will finally reach people around the world.”
Kim presented the algorithm at SLEEP 2025 and at World Sleep 2025.
He is also working with Professor Eun Yeon Joo’s team at Samsung Medical Center to develop even more advanced sleep recommendation technology. Together, they created “SLEEPS,” an algorithm that predicts sleep disorders.
The algorithm is available on Samsung Galaxy smartwatches.
