Browsing by Author "Roy Choudhury, Romit"
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Item Open Access Building Blocks for Tomorrow's Mobile App Store(2012) Manweiler, Justin GregoryIn our homes and in the enterprise, in our leisure and in our professions, mobile computing is no longer merely "exciting;" it is becoming an essential, ubiquitous tool of the modern world. New and innovative mobile applications continue to inform, entertain, and surprise users. But, to make the daily use of mobile technologies more gratifying and worthwhile, we must move forward with new levels of sophistication. The Mobile App Stores of the future must be built on stronger foundations.
This dissertation considers a broad view of the challenges and intuitions behind a diverse selection of such new primitives. Some of these primitives will mitigate existing and fundamental challenges of mobile computing, especially relating to wireless communication. Others will take an application-driven approach, being designed to serve a novel purpose, and be adapted to the unique and varied challenges from their disparate domains. However, all are related through a unifying goal, to provide a seamless, enjoyable, and productive mobile experience. This dissertation takes view that by bringing together nontrivial enhancements across a selection of disparate-but-interrelated domains, the impact is synergistically stronger than the sum of each in isolation. Through their collective impact, these new "building blocks" can help lay a foundation to upgrade mobile technology beyond the expectations of early-adopters, and into seamless integration with all of our lives.
Item Open Access Enabling Context-Awareness in Mobile Systems via Multi-Modal Sensing(2013) Bao, XuanThe inclusion of rich sensors on modern smartphones has changed mobile phones from simple communication devices to powerful human-centric sensing platforms. Similar trends are influencing other personal gadgets such as the tablets, cameras, and wearable devices like the Google glass. Together, these sensors can provide
a high-resolution view of the user's context, ranging from simple information like locations and activities, to high-level inferences about the users' intention, behavior, and social interactions. Understanding such context can help solving existing system-side
challenges and eventually enable a new world of real-life applications.
In this thesis, we propose to learn human behavior via multi-modal sensing. The intuition is that human behaviors leave footprints on different sensing dimensions - visual, acoustic, motion and in cyber space. By collaboratively analyzing these footprints, the system can obtain valuable insights about the user. We show that the
analysis results can lead to a series of applications including capturing life-logging videos, tagging user-generated photos and enabling new ways for human-object interactions. Moreover, the same intuition may potentially be applied to enhance existing
system-side functionalities - offloading, prefetching and compression.
Item Open Access Practical Architectures for Fused Visual and Inertial Mobile Sensing(2015) Jain, PuneetCrowdsourced live video streaming from users is on the rise. Several factors such as social networks, streaming applications, smartphones with high-quality cameras, and ubiquitous wireless connectivity are contributing to this phenomenon. Unlike isolated professional videos, live streams emerge at an unprecedented scale, poorly captured, unorganized, and lack user context. To utilize the full potential of this medium and enable new services on top, immediate addressing of open challenges is required. Smartphones are resource constrained -- battery power is limited, bandwidth is scarce, on-board computing power and storage is insufficient to meet real-time demand. Therefore, mobile cloud computing is cited as an obvious alternative where cloud does the heavy-lifting for the smartphone. But, cloud resources are not cheap and real-time processing demands more than what the cloud can deliver.
This dissertation argues that throwing cloud resources at these problems and blindly offloading computation, while seemingly necessary, may not be sufficient. Opportunities need to be identified to streamline big-scale problems by leveraging in device capabilities, thereby making them amenable to a given cloud infrastructure. One of the key opportunities, we find, is the cross-correlation between different streams of information available in the cloud. We observe that inferences on a single information stream may often be difficult, but when viewed in conjunction with other information dimensions, the same problem often becomes tractable.
Item Open Access Restructuring Wireless Systems using PHY Layer Information(2012) Sen, SouvikWireless and mobile systems play an increasingly important role in our lives. Fueled by an array of innovative services and applications, mobile data traffic is surging rapidly. Traditionally, wireless traffic growth is met by acquiring new spectrum. However, wireless spectrum demand is soon going to surpass it's availability. Thus, there is an urgent need for major innovations in wireless network architecture, so that our spectrum utilization can achieve its full potential. Motivated by this problem, we explore an alternative design of physical layer aware wireless systems.
Typical approaches towards improving wireless performance is confined within the physical (PHY) or link layers of the networking stack, providing only partial so- lutions. In this thesis, we advocate to consider the entire network architecture holis- tically. We show how rich PHY layer information can be utilized to address existing challenges in wireless networking - contention resolution, rate control, interference management, etc. We design, implement, and experimentally evaluate protocols to understand network-wide implications of PHY-aware systems. We also pursue the observation that PHY layer not only encode bits but also contain rich information about the ambience, and hence can be viewed as a sensor. This sensing informa- tion can be further coupled with other phone sensors, thereby benefitting pervasive mobile services and applications. We demonstrate how this synergy can contribute towards designing precise indoor localization systems, an important building block for next generation mobile applications.
Item Open Access Sensor-Assisted Mobile Phone Localization(2011) Constandache, IonutLocalization is projected to play a critical role in mobile computing applications. Nevertheless, the state of the art is inadequate especially when operating on mobile devices. More specifically, the on-phone GPS sensor has an unacceptable energy consumption and does not operate indoors. Alternate localization techniques, based on WiFi or GSM, alleviate some of the GPS limitations but provide degraded accuracy and assume pre-installed infrastructure. As a result, these solutions need extensive war-driving for collecting location fingerprints and, in many instances, limit services to regions close to drivable paths. Moreover, when infrastructure is scarce or missing, the localization accuracy is poor. Lastly, relying on hardware deployments is costly and raises scalability concerns when targeting wide regions.
To address the shortcomings of current solutions, we propose four new localization systems: (1) CompAcc enables energy-efficient, war-driving-free localization using the phone inertial sensors and digital maps, (2) Escort provides indoor localization by exploiting the phone inertial sensors and social environments where people are mobile, (3) SurroundSense enables indoor logical localization (e.g., inside Target) by sensing the user ambiance through the phone sensors, and (4) EnLoc proposes energy-efficient localization via personalized mobility profiling and predictions.