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<title>Computer Science Department Dissertations Collection</title>
<copyright>Copyright (c) 2013 University of Massachusetts - Amherst All rights reserved.</copyright>
<link>http://scholarworks.umass.edu/cs_diss</link>
<description>Recent documents in Computer Science Department Dissertations Collection</description>
<language>en-us</language>
<lastBuildDate>Tue, 26 Mar 2013 10:20:17 PDT</lastBuildDate>
<ttl>3600</ttl>


	



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<title>Bridging The Gap Between Autonomous Skill Learning And Task-Specific Planning</title>
<link>http://scholarworks.umass.edu/open_access_dissertations/706</link>
<guid isPermaLink="true">http://scholarworks.umass.edu/open_access_dissertations/706</guid>
<pubDate>Thu, 21 Mar 2013 07:53:54 PDT</pubDate>
<description>
	<![CDATA[
	<p>Skill acquisition and task specific planning are essential components of any robot system, yet they have long been studied in isolation. This, I contend, is due to the lack of a common representational framework. I present a holistic approach to planning robot behavior, using previously acquired skills to represent control knowledge (and objects) directly, and to use this background knowledge to build plans in the space of control actions.</p>
<p>Actions in this framework are closed-loop controllers constructed from combinations of sensors, effectors, and potential functions. I will show how robots can use reinforcement learning techniques to acquire sensorimotor programs. The agent then builds a functional model of its interactions with the world as distributions over the acquired skills. In addition, I present two planning algorithms that can reason about a task using the functional models. These algorithms are then applied to a variety of tasks such as object recognition and object manipulation to achieve its objective on two different robot platforms.</p>

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</description>

<author>Sen, Shiraj</author>

<source></source>

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<title>Software Techniques to Reduce the Energy Consumption of Low-Power Devices at the Limits of Digital Abstractions</title>
<link>http://scholarworks.umass.edu/open_access_dissertations/704</link>
<guid isPermaLink="true">http://scholarworks.umass.edu/open_access_dissertations/704</guid>
<pubDate>Thu, 21 Mar 2013 07:36:48 PDT</pubDate>
<description>
	<![CDATA[
	<p>My thesis explores the effectiveness of software techniques that bend digital abstractions in order to allow embedded systems to do more with less energy. Recent years have witnessed a proliferation of low-power embedded devices with power ranges of few milliwatts to microwatts. The capabilities and size of the embedded systems continue to improve dramatically; however, improvements in battery density and energy harvesting have failed to mimic a Moore's law. Thus, energy remains a formidable bottleneck for low-power embedded systems.</p>
<p>Instead of trying to create hardware with ideal energy proportionality, my dissertation evaluates how to use unconventional and probabilistic computing that bends traditional abstractions and interfaces in order to reduce energy consumption while protecting program semantics. My thesis considers four methods that unleash energy otherwise squandered on communication, storage, time keeping, or sensing: 1) CCCP, which provides an energy-efficient storage alternative to local non-volatile storage by relying on cryptographic backscatter radio communication, 2) Half-Wits, which reduces energy consumption by 30% by allowing operation of embedded systems at below-spec supply voltages and implementing NOR flash memory error recovery in firmware rather than strictly in hardware, 3) TARDIS, which exploits the decay properties of SRAM to estimate the duration of a power failure ranging from seconds to several hours depending on hardware parameters, and 4) Nonsensors, which allow operation of analog to digital converters at low voltages without any hardware modifications to the existing circuitry.</p>

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</description>

<author>Salajegheh, Mastooreh</author>

<source></source>

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<title>Privacy-Aware Collaboration Among Untrusted Resource Constrained Devices</title>
<link>http://scholarworks.umass.edu/open_access_dissertations/696</link>
<guid isPermaLink="true">http://scholarworks.umass.edu/open_access_dissertations/696</guid>
<pubDate>Wed, 20 Mar 2013 12:55:47 PDT</pubDate>
<description>
	<![CDATA[
	<p>Individuals are increasingly encouraged to share private information with service providers. Privacy is relaxed to increase the utility of the data for the provider. This dissertation offers an alternative approach in which raw data stay with individuals and only coarse aggregates are sent to analysts. A challenge is the reliance on constrained devices for data collection. This dissertation demonstrates the practicality of this approach by designing and implementing privacy-aware systems that collect information using low-cost or ultra-low-power microcontrollers. Smart meters can generate certified readings suitable for use in a privacy-preserving system every 10 s using a Texas Instruments MSP430 microcontroller. CRFIDs-batteryless devices that operate on harvested energy from RF-can generate encrypted sub-aggregates in 17 s to contribute to a privacy-preserving aggregation system that does not rely on a trusted aggregator. A secure communication channel for CRFID tags via untrusted relays achieves a throughput of 18 Kbps.</p>

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<author>Molina-Markham, Andres David</author>

<source></source>

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