CSR: Small: Jouler: A Cross-Device Energy Management Framework for Smartphones

Suny At Buffalo, Amherst NY

Investigators

Abstract

The goal of this project is to address the problem of short battery lifetimes, which continue to frustrate users of smart phones. Existing approaches to battery management are proving too inflexible to respond to the significant variations in application program energy consumption, user behavior, charging habits, and battery lifetime expectations that both define and complicate the energy management problem. This level of diversity means that "one size fits all" approaches are likely to fail, as are approaches that make broad generalizations about applications or users: one user's favorite application may cause unacceptable battery drain for another user. One user may be willing to charge multiple times per day while another wants their phone to last all day. The project research approaches the battery lifetime problem through a novel energy management framework, named Jouler. Jouler is distinguished from other efforts in three ways: First, Jouler is automated, removing the user from the loop to reduce the burdensome and error-prone nature of manual energy management. Second, Jouler is flexible, encapsulating energy management strategies into policy modules that can be distributed through application marketplaces and installed as needed by users. By separating energy management policies from mechanisms, Jouler also enables innovation in energy management algorithms, which can now be written by developers and evaluated like apps. Third, Jouler attempts to provide a cross-device framework to allow energy managers to work successfully across broad classes of smartphone devices with different features. The educational and outreach activities of the project include a new course on energy management, a yearly challenge contest to increase interest in policy module development, and a new energy management assignment augmenting a widely-used instructional operating system.