Towards Online Personalized-Monitoring of Human Thermal Sensation Using Machine Learning Approach

Ali Youssef,Jean-Marie Aerts,Nicolás Caballero,Ahmed Youssef Ali Amer

doi:10.3390/app9163303

Abstract

Thermal comfort and sensation are important aspects of building design and indoor climate control, as modern man spends most of the day indoors. Conventional indoor climate design and control approaches are based on static thermal comfort/sensation models that view the building occupants as passive recipients of their thermal environment. To overcome the disadvantages of static models, adaptive thermal comfort models aim to provide opportunity for personalized climate control and thermal comfort enhancement. Recent advances in wearable technologies contributed to new possibilities in controlling and monitoring health conditions and human wellbeing in daily life. The generated streaming data generated from wearable sensors are providing a unique opportunity to develop a real-time monitor of an individual’s thermal state. The main goal of this work is to introduce a personalized adaptive model to predict individual’s thermal sensation based on non-intrusive and easily measured variables, which could be obtained from already available wearable sensors. In this paper, a personalized classification model for individual thermal sensation with a reduced-dimension input-space, including 12 features extracted from easily measured variables, which are obtained from wearable sensors, was developed using least-squares support vector machine algorithm. The developed classification model predicted the individual’s thermal sensation with an overall average accuracy of 86%. Additionally, we introduced the main framework of streaming algorithm for personalized classification model to predict an individual’s thermal sensation based on streaming data obtained from wearable sensors.

Highlights

Thermal comfort (TC) is an ergonomic aspect determining satisfaction with the surrounding environment and is defined as ‘that condition of mind which expresses satisfaction with the thermal environment and is assessed by subjective evaluation’ [1]
The effect of thermal environments on occupants might be assessed in terms of thermal sensation (TS), which can be defined as ‘a conscious feeling commonly graded into the categories cold, cool, slightly cool, neutral, slightly warm, warm, and hot’ [1]
25 participants are subjected to three different environmental temperatures, namely 5 ◦ C, 20 ◦ C and 37 ◦ C at two different activity levels, namely, at low level and high level

Summary

Introduction

Thermal comfort (TC) is an ergonomic aspect determining satisfaction with the surrounding environment and is defined as ‘that condition of mind which expresses satisfaction with the thermal environment and is assessed by subjective evaluation’ [1]. The effect of thermal environments on occupants might be assessed in terms of thermal sensation (TS), which can be defined as ‘a conscious feeling commonly graded into the categories cold, cool, slightly cool, neutral, slightly warm, warm, and hot’ [1]. Thermal sensation and thermal comfort are both subjective judgements, thermal sensation is related to the perception of one’s thermal state, and thermal comfort is related to the evaluation of this perception [2]. TS expresses the perception of the occupants, while TC assesses this perception, taking into account physiological and psychological factors [3].

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Conclusion