GetMobile October 2015
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A Great Time for Makers
Prabal Dutta & Iqbal Mohomed
The last few months have been especially exciting for the DIY and Maker scene. We have witnessed a wave of equipment that used to cost many tens of thousands of dollars but has now become more affordable. In this column, we do a whirlwind tour of the categories that excite us the most.
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Why and How to Use Phonelab
Jinghao Shi, Edwin Santos, and Geoffrey Challen
While smartphone app marketplaces have enabled large-scale app-level experimentation, medium-scale experimentation with the platform code implementing the app interface and providing core device services remains difficult for academic researchers. But this is where many of the ideas currently being explored by the mobile systems community must be evaluated---including new networking protocols, security and privacy mechanisms, storage abstractions, and energy management strategies. To enable these experiments, we built and are operating PhoneLab, a 175-smartphone testbed where real users run experimental Android platform builds on their primary devices. We are eager to make PhoneLab useful to the mobile systems community. To aid in this effort, this article discusses why PhoneLab might be useful for your research and provides an overview of how to use the testbed, including examples drawn from our group's current projects.
GetMobile July 2015
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Battery Fundamentals
Anthony Ferrese
The use of batteries as a portable power source has gained tremendous importance for powering mobile devices and for enabling greener and less energy-intensive transportation. Whether the demand is for a smart phone, laptop, tablet or the next wearable, the consumer demands a thinner and lighter battery while maintaining or increasing battery life at the lowest possible cost. This demand has caused many companies to increasingly consider the battery and its performance when designing their next device. While, in the past, it may have been acceptable to take an "off-the-shelf" battery that meets specifications and "plug it in", many companies are starting to implement "smart" designs that take into account specific battery chemistries and characteristics to improve overall performance. This requires a knowledge of how a battery works. With this in mind, this article gives an explanation of battery fundamentals, why batteries degrade over their life, what limits their performance, the trade-offs between high power and high energy, and current efforts to build a better battery. While many of the overall properties are similar for many battery chemistries, here we will focus on the lithium-ion battery, specifically the cobaltdioxide/ graphite lithium-ion battery, one of the most popular battery chemistries for mobile devices.
GetMobile April 2015
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Astrobiology App for Kids: Software as a Cognitive Prosthetic for Conceptualization of Astronomical Theories
Ana C. Calderon, Catherine Tryfona, Cai Smith
It is well-known that children have difficulty conceptualizing astronomical concepts, such as gravity (Schoultz et al., 2001). We argue that a solution to this is to create effective and efficient prosthetics for aiding in their thinking and visualization, and exemplify this with an app that introduces astrobiology to children. The app was designed to be a hybrid between a game-like learning app and an encyclopaedic app. Similar difficulties arise in teaching mathematics to children (see for instance, Trouche, 2003). We predict that our app might have usage not only in children's astronomical education, but could also be used by people of all ages wishing to familiarize themselves with astrobiology, in an introductory manner.
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Deployment Study Length: How Long Should a System Be Evaluated in the Wild?
Khai Truong, Julie Kientz, Nilanjan Banerjee, A. J. Brush, Ratul Mahajan
There are many different ways to evaluate a novel interactive system. However, placing that system into the hands of real users and allowing them to use it as they would like in their natural environments may arguably be the best approach to understand if it "really" works. This is because findings learned from user studies conducted in the lab or a controlled setting are limited in external validity and therefore might not generalize beyond the studied usage scenario. Furthermore, the scenario used in a controlled study often lacks full authenticity, and thus it may not faithfully represent situations from the users' live.
GetMobile January 2015
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Lab of Things in Education
Arjmand Samuel, Dean Mohamedally, Nilanjan Banerjee, A. J. Brush, Ratul Mahajan
Lately, much has been said about the Internet of Things and how it is going to change how we will live, work and play. Strategy Analytics forecasts that by 2020, every person on the planet will carry four connected devices. The majority of this growth will be driven by the interconnection of devices, sensors, smart objects and the like, and is expected to usher in changes to almost all aspects of our lives. This change will require, on the one hand, large-scale design, development and deployment of cloud and network systems; and on the other hand, design of hardware sensors, actuators, software middleware, and network protocols.
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Scikit-learn: Machine Learning Without Learning the Machinery
G. Varoquaux, L. Buitinck, G. Louppe, O. Grisel, F. Pedregosa, A. Mueller
Machine learning is a pervasive development at the intersection of statistics and computer science. While it can benefit many data-related applications, the technical nature of the research literature and the corresponding algorithms slows down its adoption. Scikit-learn is an open-source software project that aims at making machine learning accessible to all, whether it be in academia or in industry. It benefits from the general-purpose Python language, which is both broadly adopted in the scientific world, and supported by a thriving ecosystem of contributors. Here we give a quick introduction to scikit-learn as well as to machine-learning basics.
GetMobile October 2014
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A Brief History of Cloud Offload
A Personal Journey from Odyssey Through Cyber Foraging to Cloudlets
Mahadev Satyanarayanan
Every time you use a voice command on your smartphone, you are benefitting from a technique called cloud offload. Your speech is captured by a microphone, pre-processed, then sent over a wireless network to a cloud service that converts speech to text. The result is then forwarded to another cloud service or sent back to your mobile device, depending on the application. Speech recognition and many other resource intensive mobile services require cloud offload. Otherwise, the service would be too slow and drain too much of your battery.
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Democratizing Computing with App Inventor
David Wolber, Harold Abelson, Mark Friedman
MIT App Inventor is a visual blocks language that enables beginners and non-programmers to create apps for their phones and tablets. It has empowered thousands to create software with real-world usefulness, and see themselves as creators rather than only consumers in the mobile computing environment. Educationally, it offers a “gateway drug” that can help broaden and diversify participation in computing education.
