Shahriyar Amini

Toss 'n' turn: smartphone as sleep and sleep quality detector

The rapid adoption of smartphones along with a growing habit for using these devices as alarm clocks presents an opportunity to use this device as a sleep detector. This adds value to UbiComp and personal informatics in terms of user context and new performance data to collect and visualize, and it benefits healthcare as sleep is correlated with many health issues. To assess this opportunity, we collected one month of phone sensor and sleep diary entries from 27 people who have a variety of sleep contexts. We used this data to construct models that detect sleep and wake states, daily sleep quality, and global sleep quality. Our system classifies sleep state with 93.06% accuracy, daily sleep quality with 83.97% accuracy, and overall sleep quality with 81.48% accuracy. Individual models performed better than generally trained models, where the individual models require 3 days of ground truth data and 3 weeks of ground truth data to perform well on detecting sleep and sleep quality, respectively. Finally, the features of noise and movement were useful to infer sleep quality.

Caché: caching location-enhanced content to improve user privacy

We present the design, implementation, and evaluation of Caché, a system that offers location privacy for certain classes of location-based applications. The core idea in Caché is to periodically pre-fetch potentially useful location-enhanced content well in advance. Applications then retrieve content from a local cache on the mobile device when it is needed. This approach allows an end-user to make use of location-enhanced content while only revealing to third-party content providers a large geographic region rather than a precise location. In this paper, we present an analysis that examines tradeoffs in terms of storage, bandwidth, and freshness of data. We then discuss the design and implementation of an Android service embodying these ideas. Finally, we provide two evaluations of Caché. One measures the performance of our approach with respect to privacy and mobile content availability using real-world mobility traces. The other focuses on our experiences using Caché to enhance user privacy in three open source Android applications.

Trajectory-aware mobile search

Most location-aware mobile applications only make use of the users current location, but there is an opportunity for them to infer the users future locations. We present Trajectory-Aware Search (TAS), a mobile local search application that predicts the users destination in real-time based on location data from the current trip and shows search results near the predicted location. TAS demonstrates the feasibility of destination prediction in an interactive mobile application. Our user study of TAS shows using predicted destinations to help select search results positively augments the local search experience.

CrowdLearner: rapidly creating mobile recognizers using crowdsourcing

Mobile applications can offer improved user experience through the use of novel modalities and user context. However, these new input dimensions often require recognition-based techniques, with which mobile app developers or designers may not be familiar. Furthermore, the recruiting, data collection and labeling, necessary for using these techniques, are usually time-consuming and expensive. We present CrowdLearner, a framework based on crowdsourcing to automatically generate recognizers using mobile sensor input such as accelerometer or touchscreen readings. CrowdLearner allows a developer to easily create a recognition task, distribute it to the crowd, and monitor its progress as more data becomes available. We deployed CrowdLearner to a crowd of 72 mobile users over a period of 2.5 weeks. We evaluated the system by experimenting with 6 recognition tasks concerning motion gestures, touchscreen gestures, and activity recognition. The experimental results indicated that CrowdLearner enables a developer to quickly acquire a usable recognizer for their specific application by spending a moderate amount of money, often less than

Expectation and purpose: understanding users' mental models of mobile app privacy through crowdsourcing

10, in a short period of time, often in the order of 2 hours. Our exploration also revealed challenges and provided insights into the design of future crowdsourcing systems for machine learning tasks.