Abstract-Late arrival to jobs and meetings is a critical problem in a number of domains, such as building construction. Smartphones are a promising platform for detecting late arrivals and notifying affected parties due to the variety of sensors they possess, persistent Internet connection, and access to a user's calendar data. This paper presents a powerefficient cyber-physical approach to indoor/outdoor late arrival detection, called LifeSaver. The paper provides the following three contributions to the study of late arrival detection and notification with smartphones: 1) it presents a cyber-physical approach for using accelerometer data to predict when a user is moving and make more power efficient localization decisions; 2) it shows how Bluetooth beacons can be used to provide a simplified meeting room localization mechanism for smartphones; and 3) it presents empirical results showing that the cyber-physical LifeSaver late arrival detection approach uses 43% less power compared to lateness detection approaches that rely on standard localization strategies.

As mobile computing platforms become ubiquitous, the need to keep data synchronized between multiple devices becomes increasingly common. However, mobile devices have limited battery capacity, and file synchronization requires extensive use of power-hungry network interfaces. This paper introduces Syncrod, an approach for optimizing file synchronization algorithm parameters in order to minimize total energy consumption. This paper presents a formal model for describing mobile file synchronization energy consumption, and an example of fitting a general file synchronization algorithm to the provided model. Empirical results of running an energy optimization on a general file synchronization algorithm are shown to provide rapid file transfer while using near 0.003% of a standard smartphone battery energy per MB. The provided approach can be used to find the the most energy-efficient parameters for any file synchronization algorithm that can be fit into the provided formal model.