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Multiple targets detection and tracking with Doppler effect in noisy acoustic wireless sensor networksAn, Youngwon Kim 18 May 2013 (has links)
<p> This dissertation presents a new detection algorithm and high speed/accuracy tracker for tracking a single and multiple ground vehicles in noisy acoustic wireless sensor networks (WSNs). For tracking ground vehicles, acoustic WSNs have been regarded to be useful and increasingly available due to recent advancement of micro sensors technology with low cost. Requirements for WSNs applications are low computational and communication load to each sensor node as each sensor node runs with a low-power battery. </p><p> The new detection algorithm of this dissertation naturally accounts for the Doppler effect which is an important consideration for tracking higher-speed targets. The tracking system used in this study employs Kalman Filtering (KF) with the weighted sensor position centroid being used as the target position measurement. The weighted centroid makes the tracker to be independent of the detection model and changes the tracker to be near optimal, at least within the detection parameters used in the study of single target. </p><p> The new approach for a single target tracking contrasts with the previous approaches that employed more sophisticated tracking algorithms with higher computational complexity and used a power law detection model. The power law detection model, neglecting Doppler effect, is valid only for low speed targets and is susceptible to mismatch with detection by the sensors in the field. The tracking model also makes it possible to uniquely study various environmental effects on track accuracy, such as the Doppler effect, signal collision, signal delay, and different sampling time. The tracking model is shown to be highly accurate for a moving single target in both linear and accelerated motions. The computing speed is estimated to be 50∼100 times faster than the previous more sophisticated methods and track accuracy compares very favorably. </p><p> As the WSN systems face multiple targets in the real world, the study has been expanded to the multiple targets tracking including the environmental noise mitigation. Localization and tracking multiple targets which undergo merging and split in the noisy acoustic WSNs require a new approach for detection and tracking. Doppler effect is included in the detection model and an efficient noise mitigation algorithm is developed. A new rule-based tracking algorithm is also developed, which guarantees reliable tracking of multiple targets in noisy acoustic WSNs with very low computational complexity and high track accuracy. The tracking system guarantees much lower computational complexity and comparable track accuracy to more sophisticated algorithms of the previous work.</p>
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High efficiency thrust vector control allocationOrr, Jeb S. 21 June 2013 (has links)
<p> The design of control mixing algorithms for launch vehicles with multiple vectoring engines yields competing objectives for which no straightforward solution approach exists. The designer seeks to optimally allocate the effector degrees of freedom such that maneuvering capability is maximized subject to constraints on available control authority. In the present application, such algorithms are generally restricted to linear transformations so as to minimize adverse control-structure interaction and maintain compatibility with industry-standard methods for control gain design and stability analysis. Based on the application of the theory of ellipsoids, a complete, scalable, and extensible framework is developed to effect rapid analysis of launch vehicle capability. Furthermore, a control allocation scheme is proposed that simultaneously balances attainment of the maximum maneuvering capability with rejection of internal loads and performance losses resulting from thrust vectoring in the null region of the admissible controls. This novel approach leverages an optimal parametrization of the weighted least squares generalized inverse and exploits the analytic properties of the constraint geometry so as to enable recovery of more than ninety percent of the theoretical capability while maintaining linearity over the majority of the attainable set.</p>
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The use of biodegradable mulch for tomato and broccoli production| Crop yield and quality, mulch deterioration, and growers' perceptionsCowan, Jeremy Scott 24 August 2013 (has links)
<p> Biodegradable mulch may offer the benefits of polyethylene mulch for crop production with the added benefit of biodegradability. Four studies were carried out in Mount Vernon, WA to evaluate biodegradable mulch for tomato (<i>Solanum lycopersicum</i> L.) and broccoli (<i>Brassica oleracea</i> var. <i>italica</i>) production. The first study compared four biodegradable mulch treatments: BioAgri, BioTelo, WeedGuardPlus (cellulose product), and SB-PLA-10/11/12 (experimental, non-woven fabric), to polyethylene mulch and bare ground in high tunnels and in the open field for tomato yield and fruit quality over three growing seasons. Biodegradable plastic films produced yields and fruit quality comparable to polyethylene. Moreover, high tunnels increased total and marketable fruit weight five and eight times, respectively, compared to the open field. </p><p> The second study quantified relationships among visual assessment parameters and mulch mechanical properties. Visual assessments and mechanical property tests of polyethylene, BioAgri, BioTelo, WeedGuardPlus, and SB-PLA-10/11/12, were made over three growing seasons. Regression analyses found the strongest relationship overall (<i>r</i><sup>2</sup> = 0.41) to be between the percent of initial breaking force in the machine direction and log<sub> 10</sub> of percent visual deterioration. However, evaluating mulch products individually and increasing sample frequency are recommended for future research. </p><p> The third study evaluated three biodegradable mulch products, BioAgri, Crown 1, and SB-PLA-11, after soil-incorporation. The average area of recovered mulch fragments decreased for all mulch products over time. The number of mulch fragments initially increased for all mulch products, with the greatest number of Crown 1 and BioAgri fragments recovered 132 and 299 days after incorporation, respectively. At 397 days after soil-incorporation, the total area of recovered fragments of Crown 1 and BioAgri was 0% and 34% of the theoretical maximum area, respectively. </p><p> The fourth study used the diffusion of innovations framework to study perceptions about biodegradable mulch and employed the concept of "tactile space" to create sensuously rich learning environments wherein participants could interact with each other and the environment to evaluate biodegradable plastic mulch. Participants' perceptions about biodegradable mulch and attitudes toward adoption improved. Employing tactile space as a diffusion strategy may encourage non-representational learning to supplement and reinforce the knowledge claims being made at outreach/education events.</p>
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The Effect of Nanostructure on the Electrical Properties of Metal Oxide MaterialsRice, Philip Zachary 10 September 2013 (has links)
<p> Resistive random access memory (ReRAM) is a potential replacement technology for Flash and other memory implementations. Advantages of ReRAM include increased scalability, low power operation, and compatibility with silicon semiconductor manufacturing. Most of the ReRAM devices described to date have utilized thin film based metal oxide dielectrics as a resistive switching matrix. The goal of this dissertation project has been to investigate the resistive switching behavior of nanoparticulate metal oxides and to develop methods to utilize these materials in ReRAM device fabrication. To this end, nanoparticles of TiO<sub>2</sub> and HfO<sub>2</sub> were synthesized under a variety of conditions resulting in various size, shape, and crystallinity. Electrical measurements of individual nanoparticles, as well as composite films of nanoparticles, were performed with limited success. To improve the stability of nanoparticle films, a spin on glass, hydrogen silsesquioxane (HSQ), was incorporated into the film stack. Addition of HSQ prevented electrical shorting and stabilized the nanoparticle films. In addition to serving as a stabilizer for nanoparticle films, HSQ was also found to have its own resistive switching properties. Composite films consisting of HSQ and nanoparticles yielded modified switching behavior which was tunable based upon nanoparticle composition and the thickness of the nanoparticle film. Our results demonstrate that both V<sub>SET</sub> and V<sub>RESET</sub> of HSQ switching can be increased when nanoparticles are incorporated with HSQ, without any significant changes to the device's high and low resistance states. We conclude that metal oxide nanoparticles can function as the dielectric material for ReRAM and can also be used to modulate the switching properties of composite ReRAM devices.</p>
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Carbon dioxide enhanced oil recovery from the Citronelle Oil Field and carbon sequestration in the Donovan sand, southwest AlabamaTheodorou, Konstantinos 02 October 2013 (has links)
<p> Capturing carbon dioxide (CO<sub>2</sub>) from stationary sources and injecting it into deep underground geologic formations has been identified as a viable method for reducing carbon emissions to the atmosphere. Sedimentary rocks, such as sandstones overlain by shales or evaporites, are the preferred formations because their morphology and structure provide pore space, and containment for the long term storage of CO<sub>2</sub>. Sandstone formations have also served as repositories to migrating hydrocarbons, and are the sites of many oil recovery operations. For many depleted oil reservoirs, secondary waterflooding recovery methods are no longer efficient or economically viable, hence the application of tertiary CO<sub>2</sub> enhanced oil recovery (CO<sub> 2</sub>-EOR) followed by CO<sub>2</sub> storage is an attractive and cost effective business plan. </p><p> Citronelle Oil Field, located in southwest Alabama, is the largest and longest producing sandstone oil reservoir in the state, having produced more than 170 million barrels of oil from its estimated 500 million barrels of original oil in place, since its discovery in 1955. The field is in the later stages of secondary recovery by waterflooding and daily oil production has declined considerably. The field is comprised of the Upper and Lower Donovan hydrocarbon bearing sandstones, which are separated by the saline-water-bearing sandstones of the Middle Donovan. The Ferry Lake Anhydrite, which overlies the three sections, serves as their caprock. </p><p> The present work is focused on an investigation of the feasibility of a CO<sub>2</sub>-EOR project for the Citronelle Oil Field and the use of the Middle Donovan for long term CO<sub>2</sub> storage. A set of static calculations, based on estimation methods which were retrieved from publications in the field, was followed by computer simulations using MASTER 3.0, TOUGH2-ECO2N, and TOUGHREACT. Results using MASTER 3.0, for simulation of CO<sub>2</sub>-EOR, indicated that nearly 50 million barrels of additional oil could be produced by tertiary recovery. Results using TOUGH2-ECO2N and TOUGHREACT, for the simulations of CO<sub>2</sub> storage, indicated that 159 million metric tons (175 short tons) of CO<sub>2</sub> could be stored in the Middle Donovan formation. An investigation into possible CO<sub>2</sub> leakage from the reservoirs indicated that the Ferry Lake Anhydrite serves as a very reliable long term storage seal.</p><p> The present work can serve as a template for preliminary assessment of tertiary oil recovery and CO<sub>2</sub> storage of similar oil reservoirs and saline-water formations.</p>
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Model-Based Condition Monitoring and Power Management for Rechargeable Electrochemical BatteriesKim, Taesic 12 May 2015 (has links)
<p> Rechargeable multicell batteries have been used in various electrical and electronic systems, e.g., renewable energy systems, electric-drive vehicles, commercial electronics, etc. However, there are still concerns about the reliability and performance degradation of rechargeable batteries caused by low thermal stability and the aging process. A properly designed battery management system (BMS) is required for condition monitoring and control of multicell batteries to ensure their safety, reliability, and optimal performance. The goal of this dissertation research was to develop a novel BMS for rechargeable multicell batteries. </p><p> First, this research developed high-fidelity battery models for online condition monitoring and power management of battery cells. The battery models were capable of capturing the dynamic circuit characteristics, nonlinear capacity and nonlinear open-circuit voltage effects, hysteresis effect, and temperature effect of the battery cells. </p><p> Second, this research developed a novel self-X, multicell battery design. The proposed multicell battery can automatically configure itself according to the dynamic load/storage demand and the condition of each cell. The proposed battery can self-heal from failure or abnormal operation of single or multiple cells, self-balance from cell state imbalances, and self-optimize to improve energy conversion efficiency. These features were achieved by a highly efficient cell switching circuit and a high-performance condition monitoring and control system. </p><p> Moreover, this research developed several model-based condition monitoring algorithms based on the proposed battery models. First, a particle swarm optimization-based parameter identification algorithm was developed to estimate the impedance and state of charge (SOC) of batteries using the proposed hybrid battery model. Second, an algorithm combining a regression method for parameter identification, a sliding-mode observer for SOC estimation, and a two-point capacity estimation method were proposed. In addition, an electrical circuit with hysteresis model-based condition monitoring algorithm was proposed. It systematically integrates: a fast upper-triangular and diagonal recursive least square for online parameter identification, a smooth variable structure filter for SOC estimation, and a recursive total least square for maximum capacity and state of health estimation. These algorithms provided accurate, robust condition monitoring for lithium-ion batteries. Due to the low complexity, the proposed second and third algorithms are suitable for the embedded BMS applications.</p>
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Effects of communication and control latency on air traffic controller acceptance of unmanned aircraft operationsMorales, Gregory A. 11 April 2015 (has links)
<p> Integration of Unmanned Aircraft Systems (UAS) in the National Airspace System will require UAS to meet the standards expected of conventional manned aircraft, including interactions with air traffic controllers (ATCo). To study the effect UAS delays have on ATCo acceptance of UAS operations eight ATCos managed traffic scenarios with conventional manned aircraft and one UAS. To mimic the potential latencies of UAS operations 1.5 or 5 second delays were added to the UAS pilot's verbal and execution initiation responses. Delays were either constant or variable within each scenario. While ATCos were tolerant of UAS delays, the duration and consistency of verbal and execution delays did affect communications and ATCos' experiences managing traffic. Limitations and recommendations for future research are discussed.</p>
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Effect of Solar Panel Cooling on Photovoltaic PerformanceAli, Rehan 10 September 2014 (has links)
<p> One of the main problems in using the photovoltaic system is the low energy conversion efficiency of photovoltaic cells and, furthermore, during the long operational period of solar cells, their energy conversion efficiency decreases even more due to increase in operating cell temperature over a certain limit. One way of improving the efficiency of photovoltaic system is to maintain a low operating temperature by cooling it down during its operation period. This study compares the effects of cooling on the performance of photovoltaic system. Experiments are performed on the solar panel inclined at fixed 45° angle without active cooling initially to have a set of reference performance parameters for comparison. Afterwards, cooling of the solar panel is carried out using air and water, separately, as the cooling fluids. I-V tests and temperature tests, for all the cases, are performed for comparative analysis. The energy balance calculations showed that the experimental results are in conformity with the theoretical results. The results further showed that the cooling of photovoltaic system using water over the front surface enhances the performance even more as compared to air cooling of solar panel. </p>
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A Magnetophoretic Bioseparation ChipGuo, Chuan 10 September 2014 (has links)
<p> This thesis presents the modeling, design, fabrication, and testing of a magnetophoretic bioseparation chip for isolation of biomaterials such as cells, antigens or DNA from their native environment. This microfluidic-based bioseparation device has several unique features, including locally engineered magnetic field gradients and a continuous flow with a buffer switching scheme to improve the performance of the separation process. The overall dimensions of the device are 25 mm by 75 mm by 1 mm. The cell purity was found to increase with increasing the sample flow rate. However, the cell recovery decreases with an increase in the flow rate. A compressive parametric study is performed to investigate the effects of channel height, substrate thickness, magnetic bead size, cell size, flow rate, and the number of beads per cell on the cell separation performance.</p>
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Large area all-elastomer tactile sensors for robotic skinsBlock, Peter 10 September 2014 (has links)
<p> This work demonstrates the first low cost, all-elastomer capacitive tactile arrays compatible with roll-to-roll manufacturing. A new manufacturing process has been developed in which elastomer sheets are covered with a stencil, spray coated with conductive elastomer on one or both sides, and stacked to create the sensor array. These arrays are highly flexible and can withstand large strains. Sensor costs are below $0.12/sensor in small quantities. Some variants in the fabrication process result in a slightly curved sensor so the change in capacitance is highly nonlinear at low pressures, but approaches theoretical sensitivities at higher pressures. The sensors have been determined to be highly sensitive, with a sensor resolution of 0.5 Pa and reveal a repeatable response from 1 kPa up to 120 kPa. A variety of materials ranging in modulus, thickness and texture were investigated for static, dynamic, and spatial location testing.</p>
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