Smart Buildings

Professor Choi develops integrated, human-centered frameworks for intelligent environmental control in a building. The physiological signals of the occupants, their environmental satisfaction data, and their ambient environmental data are integrated by using sensing agents (such as wearable as well as remote sensors), survey tools, and embedded environmental sensors in the building. This integrative approach enables users’ data-driven, multi-criteria decisions for determining building thermal, air, lighting, and acoustic environment system controls/designs that will potentially lower energy usage awhile improving occupant comfort. The incredible volume of data needed to inform these decisions make IMSC a natural partner for the development of Dr. Choi’s frameworks.

Human-Building Integration

This project develops an integrated human-centered framework for intelligent environmental control in a building. The physiological signals of the occupants, as well as their ambient environmental data, are integrated by using sensing agents (such as wearable/remote sensors) and embedded environmental sensors in the building. This novel concept embodies an integrative approach that promotes viable bio-sensing-driven multi-criteria decisions for determining building thermal and lighting system controls.

This human-centered approach provides a framework that will 1) address sensor data processing and analysis challenges that are inherent in large and dynamic datasets generated from sensing agents; 2) develop methods for optimizing decisions and solutions to multiple-criteria problems pertaining to occupants’ preferences; and 3) establish a human-centered control approach that is integrated with a conventional control system for building retrofits to enable real-time decision making and system optimization that will enhance energy efficient operations and occupants’ comfort.

Human physiological signals, as a proactive consideration for an interactive variable in the control system, not only help to confirm an occupant’s environmental sensations and comfort perceptions but they also optimally maintain a building’s systems operations without overshooting which results in energy savings. There has been still only limited progress in human physiology-based environmental control approaches in the building engineering discipline. Our interdisciplinary researcher team has identified the possibility of using human physiological signals directly to estimate a user’s thermal and visual sensations in real time with the help of advanced sensing technologies, such as wearable devices. These sensing-driven environmental comfort models were integrated with a building systems control and revealed a 20-35% savings potential on the energy usage for cooling, heating, and lighting, as compared to using the conventional rule-based control by eliminating the overshooting systems control within the individuals’ comfort ranges.

Selected Publications in Human-Building Integration

• Choi, J., Yeom, D. “Investigation of the Relationship between Thermal Sensations of Local Body Areas and the Whole Body in an Indoor Built Environment”, Energy and Buildings, 2017, V.149, pp. 204-215.
• Choi, J., Yeom, D. “Study of Data-Driven Thermal Sensation Prediction Model as a Function of Local Body Skin Temperatures in a Built Environment Environments”, Building and Environment, 2017, V.121, pp. 130-147.
• Choi, J., Yeom, D. “Investigation on the Differences of Physiological Responses and Thermal Sensations between Immersive Virtual and Indoor Built Environments”, Indoor and Built Environment.
• Choi, J., Zhu, R. “Investigation of the potential use of human eye pupil sizes to estimate visual sensations in the workplace environment”. Journal of Building and Environment, 2015. V. 88, pp. 73-81.

Comprehensive Post-Occupancy Evaluation: Impacts of Human and Spatial Factors on User Satisfaction in Office Environments

This study suggests an integrated POE, that combined a quantifiable environmental dataset to indicate each individual occupant’s satisfaction with each IEQ element. At 411 workstations in modern offices located in Southern California of the U.S., on-site IEQ measurements and user satisfaction surveys were conducted. Advanced data mining on the collected data are also conducted within specific categories of building types, spatial attributes, and human factors. These analyses reveal significant relationships that exist between human factors and IEQ satisfaction, as well as environmental conditions, including gender, age, workstation location, etc. These relationships could be ranked in accordance with the impact that sensitivities of individual IEQ elements using a decision tree algorithm, have on human physiological conditions. These findings suggested a hierarchical approach as an optimal design solution to maximize the occupants’ well-being in their workplace environments. Therefore, these results reinforced the necessity for an integrated POE with consideration of human and environmental factors in order to provide enhanced/optimal IEQ design solutions for specifically-targeted population and spatial conditions.

Selected Publications in Comprehensive Post-Occupancy Evaluation

• Choi, J., Moon, J. “Impacts of Human and Spatial Factors on User Satisfaction in Office Environment”, Building and Environment, 2017. V. 114, pp. 23-35.
• Choi, J., Loftness, V. Aziz, A. “Post-occupancy evaluation of 20 office buildings as basis for future IEQ standards and guidelines”. Journal of Energy and Buildings, 2012. V. 46, pp.165-175.