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CoolSpots enable a wireless mobile device to automatically switch between multiple radio interfaces, such as WiFi and Bluetooth, in order to increase battery lifetime. The main contribution of this work is an exploration of the policies that enable a system to switch among these interfaces, each with diverse radio characteristics and different ranges, in(More)
Reducing the energy consumption of PCs is becoming increasingly important with rising energy costs and environmental concerns. Sleep states such as S3 (suspend to RAM) save energy, but are often not appropriate because ongoing networking tasks, such as accepting remote desktop logins or performing background file transfers, must be supported. In this paper(More)
IP based telephony is rapidly gaining acceptance over traditional means of voice communication. Wireless LANs are also becoming ubiquitous due to their inherent ease of deployment and decreasing costs. In enterpriseWi-Fi environments, VoIP is a compelling application for devices such as smart phones with multiple wireless interfaces. However, the high(More)
Desktop computers are an attractive focus for energy savings as they are both a substantial component of enterprise energy consumption and are frequently unused or otherwise idle. Indeed, past studies have shown large power savings if such machines could simply be powered down when not in use. Unfortunately , while contemporary hardware supports low power "(More)
Buildings are known to be the largest consumers of electricity in the United States, and often times the dominant energy consumer is the HVAC system. Despite this fact, in most buildings the HVAC system is run using primitive static control algorithms based on fixed work schedules causing wasted energy during periods of low occupancy. In this paper we(More)
Buildings are among the largest consumers of electricity in the US. A significant portion of this energy use in buildings can be attributed to HVAC systems used to maintain comfort for occupants. In most cases these building HVAC systems run on fixed schedules and do not employ any fine grained control based on detailed occupancy information. In this paper(More)
Accurate power characterization is important in computing platforms for several reasons ranging from power-aware adaptation to power provisioning. Power characterization is typically obtained through either direct measurements enabled by physical instrumentation or model-ing based on hardware performance counters. We show, however, that linear-regression(More)
Presenting a fairly controlled environment for instrumentation and implementation of energy use policies, the University of California at San Diego provides an excellent testbed to characterize and understand energy consumption of buildings at the scale of a small town with over 45,000 residents. We present data collected from four selected buildings that(More)
Improving energy efficiency in buildings is a key objective for sensor researchers and promises significant reductions in energy usage across the world. The key technological driver for these gains are the novel sensor network deployments and the large amounts of data that they generate. The challenge however is making sense of this data, and using it(More)
Inferring human activity is of interest for various ubiquitous computing applications, particularly if it can be done using ambient information that can be collected non intrusively. In this paper, we explore human activity inference, in the context of energy consumption within a home, where we define an "activity" as the usage of an electrical appliance,(More)