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—Managing energy efficiently is paramount in modern smartphones. The diverse range of wireless interfaces and sensors , and the increasing popularity of power-hungry applications that take advantage of these resources can reduce the battery life of mobile handhelds to few hours of operation. The research community, and operating system and hardware vendors(More)
Mobile phones now offer users capabilities that rival those of general purpose computers. However, despite the myriad applications they support, mobile systems remain notoriously opaque. Mobile operating systems tightly control access to system resources and network traffic. The opacity of mobile systems to monitoring presents two serious drawbacks. First,(More)
In developing regions, Internet connectivity is extremely poor, while mobile phone penetration is much higher. The inhabitants of developing countries still rely on traditional social mechanisms, such as word-of-mouth, to gather most information that they use in everyday life. In this paper, we propose Goose, a Social Network Service (SNS) architecture for(More)
Mobile phones and tablets can be considered as the first incarnation of the post-PC era. Their explosive adoption rate has been driven by a number of factors, with the most signifcant influence being applications (apps) and app markets. Individuals and organizations are able to develop and publish apps, and the most popular form of monetization is mobile(More)
Despite the advances in battery technologies, mobile phones still suffer from severe energy limitations. Modern handsets are rich devices that can support multitasking thanks to their high processing power and provide a wide range of resources such as sensors and network interfaces with different energy demands. There have been multiple attempts to(More)
The popularity of smartphones, cloud computing, and the app store model have led to cellular networks being used in a completely different way than what they were designed for. As a consequence, mobile applications impose new challenges in the design and efficient configuration of constrained networks to maximize application's performance. Such difficulties(More)
Mobile phones in the 3G/4G era enable us to stay connected not only to the voice network, but also to online services like social networks. In this paper, we study the energy and network costs of mobile applications that provide continuous online presence (e.g. WhatsApp, Facebook, Skype). By combining measurements taken on the mobile and the cellular access(More)
Cellular network performance is often viewed as primarily dominated by the radio technology. However, reality proves more complex: mobile operators deploy and configure their networks in different ways, and sometimes establish network sharing agreements with other mobile carriers. Moreover, regulators have encouraged newer operational models such as Mobile(More)
The security of today's Web rests in part on the set of X.509 certificate authorities trusted by each user's browser. Users generally do not themselves configure their browser's root store but instead rely upon decisions made by the suppliers of either the browsers or the devices upon which they run. In this work we explore the nature and implications of(More)