243 research outputs found

    A Nine Month Report on Progress Towards a Framework for Evaluating Advanced Search Interfaces considering Information Retrieval and Human Computer Interaction

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    This is a nine month progress report detailing my research into supporting users in their search for information, where the questions, results or even thei

    Moving Targets: Geographically Routed Human Movement Networks

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    We introduce a new communication paradigm, Human-to-human Mobile Ad hoc Networking (HuManet), that exploits smartphone capabilities and human behavior to create decentralized networks for smartphone-to-smartphone message delivery. HuManets support stealth command-and-control messaging for mobile BotNets, covert channels in the presence of an observer who monitors all cellular communication, and distributed protocols for querying the state or content of targeted mobile devices. In this paper, we introduce techniques for constructing HumaNets and describe protocols for efficiently routing and addressing messages. In contrast to flooding or broadcast schemes that saturate the network and aggressively consume phone resources (e.g., batteries), our protocols exploit human mobility patterns to significantly increase communication efficiency while limiting the exposure of HuManets to mobile service providers. Our techniques leverage properties of smartphones ā€“ in particular, their highly synchronized clocks and ability to discern location information ā€“ to construct location profiles for each device. HuManetsā€™ fully-distributed and heuristic-based routing protocols route messages towards phones with location profiles that are similar to those of the intended receiver, enabling efficient message delivery with limited effects to end-to-end latency

    Understanding Effects of Presentation on Concept Learning in Technology Supported Learning

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    The world of technology has had a significant impact on learning and instructional domain. Today, a large number of devices and software are specifically designed to afford faster and effective learning and instruction. They have not only erased the physical boundaries to resources in education but have also helped create new interactions and engagements for learners and instructors. With this changed scenario, the content or instructional material also needs our attention to become usable and compatible with the changed learning styles and preferences of the learners today. Not only does the content need to seamlessly integrate with the delivery methodology and technology but also utilize the capabilities offered by it to enhance the learning experience. For higher order learning content such as concepts and principles that involve deeper cognitive processes, there is a need to understand how instructional material can be made more effective in technology supported environment. The goal of this experimental study was to investigate if conceptual learning in electronically delivered self-paced format can be made more usable and effective with right amount of content and presentation. It presented stimulus (concept attributes) in five different variations of information presentations and made a comparative assessment of performances using post-stimulus questions as a measure of a learner\u27s ability to generalize a concept. The eye-tracking methodology used in this study provided an opportunity to understand learner\u27s perceptual processing during learning a concept. The results of this study indicated that too much information does not help in concept learning. At the same time, providing some learner control on display of information and providing information in smaller units help the cognitive processes involved in learning a concept. Though not statistically significant, the trend showed reduction in work overload and better performance with learner-controlled progressive display. Qualitative analysis also supports the learner satisfaction and preference for progressive presentation with learner control

    Information-Theoretic Active Perception for Multi-Robot Teams

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    Multi-robot teams that intelligently gather information have the potential to transform industries as diverse as agriculture, space exploration, mining, environmental monitoring, search and rescue, and construction. Despite large amounts of research effort on active perception problems, there still remain significant challenges. In this thesis, we present a variety of information-theoretic control policies that enable teams of robots to efficiently estimate different quantities of interest. Although these policies are intractable in general, we develop a series of approximations that make them suitable for real time use. We begin by presenting a unified estimation and control scheme based on Shannon\u27s mutual information that lets small teams of robots equipped with range-only sensors track a single static target. By creating approximate representations, we substantially reduce the complexity of this approach, letting the team track a mobile target. We then scale this approach to larger teams that need to localize a large and unknown number of targets. We also examine information-theoretic control policies to autonomously construct 3D maps with ground and aerial robots. By using Cauchy-Schwarz quadratic mutual information, we show substantial computational improvements over similar information-theoretic measures. To map environments faster, we adopt a hierarchical planning approach which incorporates trajectory optimization so that robots can quickly determine feasible and locally optimal trajectories. Finally, we present a high-level planning algorithm that enables heterogeneous robots to cooperatively construct maps

    The Use of Multiple Slate Devices to Support Active Reading Activities

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    Reading activities in the classroom and workplace occur predominantly on paper. Since existing electronic devices do not support these reading activities as well as paper, users have difficulty taking full advantage of the affordances of electronic documents. This dissertation makes three main contributions toward supporting active reading electronically. The first contribution is a comprehensive set of active reading requirements, drawn from three decades of research into reading processes. These requirements explain why existing devices are inadequate for supporting active reading activities. The second contribution is a multi-slate reading system that more completely supports the active reading requirements above. Researchers believe the suitability of paper for active reading is largely due to the fact it distributes content across different sheets of paper, which are capable of displaying information as well as capturing input. The multi-slate approach draws inspiration from the independent reading and writing surfaces that paper provides, to blend the beneficial features of e-book readers, tablets, PCs, and tabletop computers. The development of the multi-slate system began with the Dual-Display E-book, which used two screens to provide richer navigation capabilities than a single-screen device. Following the success of the Dual-Display E-book, the United Slates, a general-purpose reading system consisting of an extensible number of slates, was created. The United Slates consisted of custom slate hardware, specialized interactions that enabled the slates to be used cooperatively, and a cloud-based infrastructure that robustly integrated the slates with users' existing computing devices and workflow. The third contribution is a series of evaluations that characterized reading with multiple slates. A laboratory study with 12 participants compared the relative merits of paper and electronic reading surfaces. One month long in-situ deployments of the United Slates with graduate students in the humanities found the multi-slate configuration to be highly effective for reading. The United Slates system delivered desirable paper-like qualities that included enhanced reading engagement, ease of navigation, and peace-of-mind while also providing superior electronic functionality. The positive feedback suggests that the multi-slate configuration is a desirable method for supporting active reading activities

    An Empirical Analysis of Internet Use on Smartphones: Characterizing Visit Patterns and User Differences

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    The original vision of ubiquitous computing was for computers to assist humans by providing subtle and fitting technologies in every environment. The iPhone and similar smartphones have provided continuous access to the internet to this end. In the current thesis, my goal was to characterize how the internet is used on smartphones to better understand what users do with technology away from the desktop. Naturalistic and longitudinal data were collected from iPhone users in the wild and analyzed to develop this understanding. Since there are two general ways to access the internet on smartphonesā€”via native applications and a web browserā€”I describe usage patterns through each along with the influence of experience, the nature of the task and physical locations where smartphones were used on these patterns. The results reveal differences between technologies (the PC and the smartphone), platforms (native applications and the mobile browser), and users in how the internet was accessed. Findings indicate that longitudinal use of web browsers decreased sharply with time in favor of native application use, web page revisitation through browsers occurred very infrequently (approximately 25% of URLs are revisited by each user), bookmarks were used sparingly to access web content, physical location visitation followed patterns similar to virtual visitation on the internet, and Zipf distributions characterize mobile internet use. The web browser was not as central to smartphone use compared to the PC, but afforded certain types of activities such as searching and ad hoc browsing. In addition, users systematically differed from each other in how they accessed the internet suggesting different ways to support a wider spectrum of smartphone users
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