 
Research Focuses on Energy Efficiency for Ubiquitous Computing Needs
CU-Boulder computer science Professor Dirk Grunwald is working on developing energy-efficient computers and software. Through this work, he hopes to both aid the development of ubiquitous computing and reduce the energy needed by conventional computers. Most work on low-power or energy-efficient computing is focused on the circuits and physical design of computer chips. But Grunwald's research group is designing energy-efficient computer architectures and operating systems using a combination of simulation and physical experimentation. In present day computer chips, the energy needed to perform a task is proportional: Time * Voltage2 * Frequency. The faster a computer runs (e.g., 500Mhz), the more energy it consumes, unless the voltage is reduced. Most computers operate at a fixed voltage and fixed clock frequency. More recent computers can reduce the processor frequency but this may cause certain tasks to take longer, meaning no energy is actually saved. Future processor designs will allow the voltage to be varied over time, or will allow multiple voltages to be used within a single processor, providing considerable energy savings. Grunwald and his students are working on a computer design that controls when the voltage should be adjusted, or what individual instructions should be executed on the low-voltage (slower) portion of a processor. Professor Grunwald's research group is developing an energy-efficient operating system based on the popular Linux O/S. The operating system contains information about how people want to use a computer; if the user wants a more responsive system, the operating system can adjust the processor to be more responsive at the expense of more energy. Grunwald is working on this project with researchers at the Compaq Western Research Lab in Palo Alto, where he recently spent a sabbatical year working on the Itsy pocket computer. The Itsy computer easily fits in a shirt pocket but has the capabilities of a desktop computer. The 200Mhz processor is powerful enough for speech and handwriting recognition, and there's enough memory to run large programs such as the popular game Doom and the Java programming environment. The Itsy also has innovative input devices, including a "rock and scroll" input that uses hand motions rather than a mouse or pen. Best of all, the Itsy runs on a pair of AAA batteries! The Itsy provides a powerful research platform for understanding how to make computers more energy-efficient, while also exploring the world of ubiquitous computing. Through collaboration with companies such as Compaq, students at the University of Colorado have an opportunity to design the future of computing.  Engineering Home |
Several years ago, researcher Mark Weiser at the Xerox Palo Alto Research Center coined the term "ubiquitous computing" to describe a future in which computers permeate all aspects of our daily lives. The prevalence of pocket computers (such as Palm Pilots) and the newly emerging smart-phones are the most recent examples, but more radical applications are emerging. In the future, computers may be built into the walls of buildings, for example. Following a disaster, those computers might form an ad hoc network of distributed sensors that detect sound, heat, or chemicals and relay that information to rescue workers. Since many of these small computers use batteries, energy efficiency is increasingly important.