Abstract: A network architecture providing host migration transparency. In Proceedings of SIGCOMM'9I (Sept. 1991), pp. 209-22O. C. The portable common runtime approach to interoperability. In Proceedings of the ACM Sympgsium on Operating Sy,~tems Principles (Dec. 1989). About the Author: MARK WEISER is principal scientist and manager of tlhe Computer Science laboratory at Xerox PARC. Current research interests include new theories of automatic memory reclamation (garbage collection), visualization of operating system internals, t~biquitous computing and embodied virtuality. Permission to copy without fee all or part of this material is granted provided that the copies are not made or distribta~ed for direct commercial advantage, the ACM copyright notice and the title of the publication and its date appear, and nolice is give that copying is by permission of the Association for Computing Machinery. To copy o:herwise, or to republish, requires a fee and/or specific permission. Responsive Office Environments team of facilltles, staff and omputer science researchers t xerox PARC IS exploring applications of ubiquitous computing to energy management and environmental control [1]. By interconnecting PARC's rich computational Infrastructure with a computerized building management system (BMS) that controls heating, air conditioning , lighting and desktop appliances , we plan to explore new strategies for energy conservation and office comfort control. Over the past 20 years, the designers of heating, ventilation, and air conditionIng (HVAC) systems have gradually shifted toward the use of digital computers [2], replacing direct manual control and simple analog feedback loops such as thermostats. Digital control makes possible more flexible, precise, and complex control strategies that In turn can provide significant energy savIngs. For example, most computer-controlled buildings offer automatic temperature setbacks to reduce energy consumption after working hours and on weekends. Many systems also control lighting to save additional energy. Current progress In low-cost distributed computing, communications, and sensing technologies will enable future building management systems to be much more responsive to individual preferences and activities. The following are examples of the types of enhancements that are possible: • Small, location-sensing mobile computers such as PARCTabs provide an ideal Interface to allow office occupants and maintenance staff to set parameters (such as preferred ranges for temperature and light level) and receive feedback about current conditions. • Occupancy sensors are already used at PARC to avoid heating or cooling conference rooms when they are not in use. We are now experlmentlng with user-selectable strategies for switching off lights, computer displays, and …