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ceyhunolcan/README.md

Ceyhun Olcan — Building reliable, fairness-audited AI for behavioral health

Roles

§ About

Can passive signals from phones, wearables, and the environment reliably model behavioral health over months and years?

My work builds the methods, audits, and foundation models needed to answer that — with a focus on reliability, fairness, and clinical translation. I sit at the intersection of biomedical engineering, computational psychiatry, and climate–health systems.

The field is moving fast on capability; my bet is that what makes these systems actually deployable is the unglamorous infrastructure underneath — signal forensics, drift monitoring, fairness audits, and honest evaluation.

location:   Hanover, NH
program:    Biomedical Engineering
institution: Dartmouth College
labs:
  - AIM HIGH Lab (Geisel)
  - Empower Lab (Thayer)
status:     pretraining v1 · auditing
open_to:    collaborations, PhD talks

§ Research

Four research threads, one question

Selected Preprints

Reliability of Passive Sensing Data: A Multi-Method Evaluation in Depression   PsyArXiv, 2026 Langener, Lee, Castro-Alvarez, Lampe, Enbar-Salo, Ramrakhiani, Olcan, Dorris, Price, Heinz, et al. How reliably do wearable and smartphone passive sensing actually capture signal in depression? A multi-method evaluation.

Smartphone Missingness as a Depression Biomarker   medRxiv, 2026 Olcan, C. Reframes smartphone data missingness — usually treated as a nuisance — as itself a depression biomarker, via a baseline-controlled re-analysis of the StudentLife cohort.

Moderate-to-Severe Olfactory Dysfunction Marks Accelerated Phenotypic Aging in U.S. Adults   Research Square, 2026 Olcan, C. Population-scale evidence that moderate-to-severe olfactory dysfunction tracks with accelerated phenotypic aging.

Full list on ORCID and Google Scholar.

§ Featured Work

Visual abstract: smartphone missingness as a depression biomarker

In passive-sensing studies, missing data is treated as noise — something to impute, weight, or drop. This paper shows the opposite: in a re-analysis of the StudentLife cohort, sparse days carry depression signal that dense days don't. The mechanism is intuitive once you see it. Depressed individuals withdraw — fewer screen unlocks, fewer SMS, fewer app launches. The missingness pattern itself is the symptom, not a measurement failure.

Active Code

Self-supervised pretraining over months of wearable, smartphone, and environmental streams. Built for transfer to downstream behavioral-health forecasting.

Auditing toolkit for wearable physiological signals — quality, drift, demographic fairness. Methodological companion to the Reliability of Passive Sensing preprint.

NHANES pipeline linking olfactory dysfunction to circadian rhythm fragmentation and activity reduction. Companion to the Olfactory Dysfunction & Phenotypic Aging preprint.

Risk analytics and strategic systems modeling engine.

§ Principles

Behavioral health AI should be    — or it shouldn't ship.

Toolchain

A fighter strafes my contribution graph

Open to research collaborations

 

Hanover, NH · Dartmouth College

Pinned Loading

  1. longitudinal-health-foundation-model longitudinal-health-foundation-model Public

    Self-supervised multimodal foundation model for longitudinal behavioral health: wearable + smartphone + climate, with fairness audit, climate-regime generalization, and integrated-gradients interpr…

    Python 1

  2. od-activity-rhythm od-activity-rhythm Public

    Analysis pipeline for: Olfactory dysfunction, daytime activity reduction, and 24-hour rhythm fragmentation in NHANES 2013-14. Companion code for Olcan, in preparation.

    HTML 1

  3. biomedical-signal-forensics-lab biomedical-signal-forensics-lab Public

    An open-source toolkit for auditing wearable physiological signals: signal quality, algorithmic fairness, causal sensitivity, and downstream-task impact.

    Python 2

  4. latent-human-dynamics-lab latent-human-dynamics-lab Public

    Multimodal state-space framework for modeling physiological-behavioral-environmental dynamics. Research prototype.

    Python 1

  5. strafe strafe Public

    Your GitHub contributions, on patrol. Animated space-combat contribution graph for profile READMEs.

    TypeScript