Abstract
This paper describes the structure, design and implementation of a building/environment data and information system, called BeDIS for short. It is designed to support fine-scale, location-specific services provided by smart devices and mobile applications in large smart buildings. Structured as a fog, it remains responsive when overloaded and degrades gracefully when network connection is disrupted and parts of it damaged. During normal times, it enables hundreds and thousands of people to locate themselves sufficiently accurately and navigate amidst dense crowd and moving objects via their mobile phones. When triggered by a disaster/emergency alert from responsible government agencies or the building safety system, BeDIS functions as a system of micro data servers for delivering location- and situation-specific emergency response instructions to people and decision support data to active smart devices and applications within fractions of a second to seconds.