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<p>    </p> <p>An energy harvesting system (EHS) provides the intriguing possibility of battery-less computing and enables various applications such as wearable, industrial or environmental sensors, and im- plantable medical devices. The biggest challenge of EHS is the instability of energy sources (e.g., Wi-Fi, solar, thermal energy, etc.) which causes unpredictable and frequent power outages. To address the challenge, existing works introduce software-based and hardware-based power failure recovery solutions that ensure program correctness across a power outage. However, they cause a significant performance overhead without providing the high quality of service in reality, and suffer from a reliability issue. In this dissertation, we address the limitations of recovery solutions across the system stack, from the compiler-directed approach and run-time systems to hardware mechanisms, and demonstrate the effectiveness of the approaches using real EHS platforms and simulators. We first present software-based recovery solutions by leveraging compiler support. We develop a compiler-directed solution built upon commodity EHS platform that can achieve 3X speedup compared to the software-based state-of-the-art solution. We also introduce a compiler optimization technique that can cooperate with run-time systems and hardware support, achieving 8X speedup compared to the software-based solution. We then present hardware-based recov- ery solutions by leveraging compiler and hardware support. We develop an architecture/compiler co-design solution that re-purposes existing hardware components in a core for power failure spec- ulative execution, a new speculation paradigm, and leverages a novel compiler analysis for cor- rect power failure recovery. Our result highlights 2 ∼ 3x performance improvement compared to the hardware-based state-of-the-art solution without requiring hardware modification. Next, we present a new cache design for EHS that can achieve cost-effective, high-performance intermit- tent computing. According to experimental results, the new cache design outperforms the state- of-the-art cache scheme by 4X and reduces the hardware cost by 90%. Finally, we present an operating system (OS)-driven solution to address a reliability problem on EHS devices while all existing works are vulnerable, causing the wrong recovery across power failure. Our experiments demonstrate that the solution causes less than 1% run-time overhead and successfully addresses the reliability problem without compromising correct power failure recovery. </p>

Wireless network devices, especially in ad hoc networks, are typically battery-powered. The growing need for energy efficiency in wireless networks, in general, and in mobile ad hoc networks (MANETs), in particular, calls for power enhancement features. The goal of this dissertation is to extend network lifetime by improving energy utilization in MANET routing. We utilize the ability of wireless network interface cards to dynamically change their transmission power, as well as the ability of wireless devices to read the remaining battery energy of the device to create a table of what we term "reluctance values," which the device uses to determine how to route packets. Choosing routes with lower reluctance values, on average and with time, leads to better utilization of the energy resources of the devices in the network. Our power-aware scheme can be applied to both reactive and proactive MANET routing protocols. As examples and to evaluate performance, the technique has been applied to the Dynamic Source Routing (DSR) protocol, a reactive routing protocol, and the Optimized Link State Routing (OLSR) protocol, a proactive routing protocol. Simulations have been carried out on large static and mobile networks. Results show improvements in network lifetime in static and certain mobile scenarios. Results also show better distribution of residual node energies at the end of simulations, which means that the scheme is balancing energy load more evenly across network nodes than the unmodified versions of DSR and OLSR. Average change in energy over time in the unmodified protocols show a steady increase with time, while the power-aware protocols show an increase in the beginning, then it levels for sometime before it starts to decrease. The power-aware scheme shows improvements in static and in coordinated mobility scenarios. In random mobility the power-aware protocols show no advantage over the unmodified protocols. / Ph. D.

This thesis on Low Impact Development (LID) Practices provides design guidelines and principles for three important LID practices: green roofs, rainwater harvesting and bioswales. The most important component of the thesis is the qualitative analysis of various case studies based on the LID objectives drawn from the literature review for each LID practice. Through the course of my research, I found that there was no one single source which provided information on the design guidelines accompanied by case examples which could help the designer with built examples where the LID practices have been executed. Therefore, developing this thesis document which provided all this information started as my masters thesis project. The document is designed to be used by people with a variety of expertise like landscape architects, landscape contractors, engineers and clients. The manual is organized into five chapters. The manual details the process of stormwater management and then gradually leads to the evolution of Low Impact Development Practices and detailing out three important LID practices: green roofs, rainwater harvesting, vegetated swales and briefly about infiltration systems. The LID principles outlined in this manual were developed over the last few years to address runoff issues associated with the new residential, commercial and industrial suburban developments. Information to develop this manual has been drawn from numerous sources like the Low Impact Design Strategies developed by the Prince George's County, Maryland, US EPA, Low Impact Development urban design tools and numerous other research papers. It is my hope that the manual will provide adequate information to its users by not only providing design guidelines but also provide built examples through the case studies. / Master of Landscape Architecture

EcoRouting refers to the determination of a route that minimizes vehicle energy consumption compared to traditional routing methods, which usually attempt to minimize travel time. EcoRoutes typically increase travel time and in some cases this increase is constrained for a viable route. While significant research on EcoRouting exists for conventional vehicles, incorporating the novel aspects of plug-in hybrids opens new areas to be explored. A prototype EcoRouting system has been developed on the MATLAB platform that takes in map information and converts it to a graph of nodes containing route information such as speed and grade. Various routes between the origin and destination of the vehicle are selected and the total energy consumption and travel time for each route are estimated using a vehicle model. The route with the minimum energy consumption will be selected as the EcoRoute unless there is a significant difference between the minimum time route and the EcoRoute. In this case, selecting a sub-optimal route as the EcoRoute will increase the probability that the driver uses a lower fuel consumption route. EcoRouting has the potential to increase the fuel efficiency for powertrains designed mainly for performance, and we examine the sensitivity of the increased efficiency to various vehicle and terrain features. The reduction in energy consumption can be achieved independent of powertrain modifications and can be scaled using publicly available parameters. / Master of Science

Large-scale sensor networks have become a reality due to recent developments in sensor node hardware and algorithms. Sensor networks can provide real-time information based on detection and tracking. This information cannot be reliable if little is known about the sensor coverage of the network, which can be defined as the total sensing range of the network due to contributions from each sensor node. Knowledge about coverage can also be useful in determining if there is any gap in coverage in the region of interest as well as improving the algorithm that determines the placement of nodes. Although coverage estimation is this thesis's central concern, other factors such as energy-efficiency and network lifespan that affect the network performance are investigated. Energy-efficiency and network lifespan depend on the communication model used for obtaining coverage information from each sensor node. This thesis proposes the use of B-splines for describing coverage efficiently. The properties of B-splines also enable communication models such as directed diffusion and hierarchical clustering to provide better performance as compared to a centralized scheme. Results obtained from simulation experiments indicate that hierarchical clustering and directed diffusion can be used effectively for coverage measurement. The hierarchical clustering model, however, exhibited some drawbacks such as a dependency on the routing scheme and poor node-failure recovery. / Master of Science