Jongyoon Choi

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Chronic stress is endemic to modern society. However, as it is unfeasible for physicians to continuously monitor stress levels, its diagnosis is nontrivial. Wireless body sensor networks offer opportunities to ubiquitously detect and monitor mental stress levels, enabling improved diagnosis, and early treatment. This article describes the development of a(More)
This paper addresses a major weakness of traditional heart-rate-variability (HRV) analysis for the purpose of monitoring stress: sensitivity to respiratory influences. To address this issue, a linear system-identification model of the cardiorespiratory system using commercial heart rate monitors and respiratory sensors was constructed. Subtraction of(More)
This article describes an approach to detecting mental stress using unobtrusive wearable sensors. The approach relies on estimating the state of the autonomic nervous system from an analysis of heart rate variability. Namely, we use a non-linear system identification technique known as principal dynamic modes (PDM) to predict the activation level of the two(More)
The ability to monitor stress levels in daily life can provide valuable information to patients and their caretakers, help identify potential stressors, determine appropriate interventions, and monitor their effectiveness. Wearable sensor technology makes it now possible to measure non-invasively a number of physiological correlates of stress, from skin(More)
This article describes a signal-processing approach to detect mental stress using unobtrusive wearable sensors. The approach addresses a major weakness of traditional methods based on heart-rate-variability (HRV) analysis: sensitivity to respiratory influences. To address this issue, we build a linear model that predicts the effect of breathing on the(More)
The objective of this paper is to assess the efficacy of deep breathing as a relaxation activity using a wearable stress monitor. For this purpose, we developed a protocol with different mentally stressful activities interleaved with regular sessions of deep breathing. We used three physiological sensors: a heart rate monitor, a respiration sensor, and an(More)
The relationship between the autonomic nervous system and the heart provides a window into our internal state, e.g., stressed vs. relaxed. This relationship has received extensive attention in cardiovascular physiology, typically with electrocardiogram recordings under laboratory conditions (e.g., pharmacological blockade). This article presents a(More)
This paper describes the problem of managing wearable sensor data and the design of an environment to support this activity. We are engaged in studies collecting data from custom‐made and off‐the‐shelf wearable and mobile sensors to explore the impact of context and physiological state on cognitive performance. The data being collected has the potential to(More)
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