Digital Commons Network^™

A Study Of Reconnection Poleward Of The Cusp: Cluster And Polar, Fathima M. Muzamil

Doctoral Dissertations

Asymmetries in plasma density and the presence of a guide field significantly alter the structure of the ion diffusion region (IDR) in symmetric, collisionless reconnection. These features have been shown by numerical simulations under moderate density asymmetries (~10), and theoretical analyses. However, very few studies have addressed these issues with in-situ observations, particularly at high magnetic latitudes. By the structure of the IDR we refer to features such as the non-colocation of the X-line and stagnation line, the distortion of the Hall magnetic and electric fields, outflow speed, outflow density etc. We have compiled a collection of Cluster crossings of …

Transparent Phased Patch Antenna Array For Beamsteering Applications, Cyle Ziegler

Master's Theses and Capstones

The ever expanding demand for wireless communications faces many challenges. As the necessity for wireless communications increases, inevitably, the impact wireless communications systems have on their environment will also increase. This is important because the environmental impact a communications system has may limit the locations in which that system can be deployed. For this reason, there is a demand for unobtrusive hardware in order to grow the wireless communications infrastructure. Furthermore, performance limiting factors associated with wireless communications can be mitigated by implementing steerable antennas, making a less obtrusive steerable antenna desired. The contribution of this work is the demonstration …

Effects Of Silvopasture Establishment On Aqueous And Gaseous Soil N Losses At The University Of New Hampshire Organic Dairy Research Farm, Kathryn Ann Slebodnik

Honors Theses and Capstones

The expansion of local agriculture in the New England region is putting increased pressure on farmers to expand their arable land base. While clear-cutting is a traditional method of converting forested land to agriculture, it is known for having adverse ecological impacts. To minimize these impacts, farmers can create a silvopasture which incorporates a portion of the original forest canopy into pastures or crop fields. This study evaluates the impact of land-use changes for agriculture on soil nitrogen (N) retention. In particular, this study investigates the differences in soil N turnover, gaseous loss, and aqueous loss among an established forest, …

Sensor Characterization And Signal Fusion For Instanteye, Wyman T. Smith

Honors Theses and Capstones

The practicality and effectiveness of using a TerraRanger Duo—a parallel sonar and infrared time-of-flight distance sensor—payload for obstacle detection is investigated for use with Physical Science Inc.’s InstantEye drone. A Python program was developed to interface with the serial data output before comparing the sensor’s empirical performance against its data sheet. The two signals from the distinct sensor modules, each with their characterized strengths and weaknesses, were then fused with a Kalman filter. This was further refined by imposing conditional weighting based on the known sensor characteristics. The filter output, with conditional corrections, was able to accurately track a single …

Trading Data For Discounts: An Exploration Of Unstructured Data Through Machine Learning In Wearable Technology, Kaleigh Alexis Zukowski

Honors Theses and Capstones

The development of computing sensor devices with the capability of tracking an individual’s activity changed the way we live and move. The data collected and generated from wearable technology provides implications to the user for leading a healthy, more active lifestyle; however, the potential data uses extend beyond the user. Significant opportunity exists in the insurance industry as it relates to discounting premiums. The purpose of this research was to provide insight as to whether insurance companies should consider offering discount on premiums for policyholders who use wearable technology to track their personal fitness by identifying and suggesting potential groups …

Understanding Ion Spectral Dynamics Near The Inner Edge Of The Plasma Sheet, Cristian Ferradas

Doctoral Dissertations

The inner magnetosphere is a highly dynamic space environment in which particles strongly interact with the magnetic and electric fields. During the last few decades, several missions have recorded the presence of dynamic spectral features of energetic ions in in situ measurements, which represent the observational signatures of ion transport, acceleration, and loss in the inner magnetosphere. These ion spectral features constitute the inner extent of access of the plasma sheet to the low L values and play an important role in the dynamics of the inner magnetosphere, yet no statistical results of their species dependence are available to date. …

Statistical Properties And Applications Of Empirical Mode Decomposition, Mahdi Hameed Al-Badrawi

Doctoral Dissertations

Signal analysis is key to extracting information buried in noise. The decomposition of signal is a data analysis tool for determining the underlying physical components of a processed data set. However, conventional signal decomposition approaches such as wavelet analysis, Wagner-Ville, and various short-time Fourier spectrograms are inadequate to process real world signals. Moreover, most of the given techniques require \emph{a prior} knowledge of the processed signal, to select the proper decomposition basis, which makes them improper for a wide range of practical applications. Empirical Mode Decomposition (EMD) is a non-parametric and adaptive basis driver that is capable of breaking-down non-linear, …

Brauer-Picard Groups And Pointed Braided Tensor Categories, Costel Gabriel Bontea

Doctoral Dissertations

Tensor categories are ubiquitous in areas of mathematics involving algebraic structures. They appear, also, in other fields, such as mathematical physics (conformal field theory) and theoretical computer science (quantum computation). The study of tensor categories is, thus, a useful undertaking.

Two classes of tensor categories arise naturally in this study. One consists of group-graded extensions and another of pointed tensor categories. Understanding the former involves knowledge of the Brauer-Picard group of a tensor category, while results about pointed Hopf algebras provide insights into the structure of the latter.

This work consists of two main parts. In the first one we …

Raidx: Raid Extended For Heterogeneous Arrays, Andras Fekete

Doctoral Dissertations

The computer hard drive market has diversified with the establishment of solid state disks (SSDs) as an alternative to magnetic hard disks (HDDs). Each hard drive technology has its advantages: the SSDs are faster than HDDs but the HDDs are cheaper. Our goal is to construct a parallel storage system with HDDs and SSDs such that the parallel system is as fast as the SSDs. Achieving this goal is challenging since the slow HDDs store more data and become bottlenecks, while the SSDs remain idle. RAIDX is a parallel storage system designed for disks of different speeds, capacities and technologies. …

Biophysical Mechanisms Of Rhythm Generation In The Pre-Bötzinger Complex, Ryan S. Phillips

Doctoral Dissertations

The pre-Bötzinger complex (pre-BötC) is an essential rhythmogenic brainstem nucleus located in the ventrolateral medulla. Rhythmic output from the pre-BötC is relayed through premotor and motor neurons to the diaphragm and intercostal muscles to drive the active inspiratory phase of breathing. The specific biophysical mechanisms responsible for generating rhythmic bursting and network synchronization are not well understood and remain a highly debated topic within the field. Through extensive experimental and theoretical work two plausible rhythmogenic mechanisms have emerged. One mechanism is based on a slowly inactivating persistent sodium current (INaP) and the other on a calcium activated non-selective cation current …

Examining The Benefits Of Instructional Assessment As Experienced By Secondary Mathematics Teachers, Willem Wallinga

Doctoral Dissertations

Mathematics teachers use a wide variety of assessment tools and methods to measure student understanding and illuminate potential learning gaps (NCTM, 2014). The most frequent and least formal types occur as observations and interactions that provide immediate feedback on the learning process (NRC, 2003, Wiliam, 2007). These Instructional Assessments emerge within the social environment of classroom activity, and serve a formative function by directly impacting the flow of discussion and motivating appropriate teaching interventions. Research has shown that formative assessment improves student performance, but is often challenging for teachers to master (OECD, 2005). The influence of annual high-stakes testing in …

A Study Of The Surface Structure Of Polymorphic Graphene And Other Two-Dimensional Materials For Use In Novel Electronics And Organic Photovoltaics, Maxwell Charles Grady

Doctoral Dissertations

For some time there has been interest in the fundamental physical properties of low- dimensional material systems. The discovery of graphene as a stable two-dimensional form of solid carbon lead to an exponential increase in research in two-dimensional and other re- duced dimensional systems. It is now known that there is a wide range of materials which are stable in two-dimensional form. These materials span a large configuration space of struc- tural, mechanical, and electronic properties, which results in the potential to create novel electronic devices from nano-scale heterostructures with exactly tailored device properties. Understanding the material properties at the …

Size-Sensitive Crystal Plasticity Finite Element Framework For Simulating Behavior Of Lamellar Metal-Metal Composites, Milan Ardeljan

Doctoral Dissertations

Growing demands for materials with enhanced and superb characteristics increase the difficulty and the amount of research necessary to be conducted in many different areas of expertise. The vast field of computational mechanics represents a significant source of valuable solutions to many of these challenges and can provide a smoother transition in the process when a new material is introduced. Experimental techniques are not always able to measure the localized material features due to the very complicated deformation conditions. As an alternative approach, full-field models are developed, such the ones contained in this dissertation that can bridge this gap and …

Self-Similar Properties And Leading Balance Scaling Structure Of Wall-Bounded Turbulent Flows, Ang Zhou

Doctoral Dissertations

Wall-bounded turbulent flows are ubiquitous in numerous technological applications, and thus much effort has been devoted to investigate their properties. Scaling analyses involving the application multiple-scale approaches are effectively used to explore parameters (Reynolds, Prandtl numbers) dependent scaling behaviors of these flows. The objective of this dissertation research is to firstly extend the analysis of self-similar behaviors on the inertial domain as admitted by the mean dynamics in wall-bounded turbulent flows (WBTF). It then mathematically and physically characterizes the existence of a leading order balance structure in both the kinetic energy and passive scalar transport budgets, and subsequently uses this …

A Noise Estimation Scheme For Blind Spectrum Sensing Using Emd, Amr Nasr

Master's Theses and Capstones

The scarcity of spectral resources in wireless communications, due to a fixed frequency allocation policy, is a strong limitation to the increasing demand for higher data rates. One solution is to use underutilized spectrum. Cognitive Radio (CR) technologies identify transmission opportunities in unused channels and avoid interfering with primary users. The key enabling technology is the Spectrum Sensing (SS). Different SS techniques exist, but techniques that do not require knowledge of the signals (non-coherent) are preferred. Noise estimation plays an essential role in enhancing the performance of non-coherent spectrum sensors such as energy detectors. In this thesis, we present an …

Performance Evaluation Of The Velodyne Vlp-16 System For Surface Feature Surveying, John Ryan Kidd

Master's Theses and Capstones

For safety of marine navigation, it is important to locate, describe, and chart the horizontal position and vertical elevation of exposed marine surface features such as piers, piles, and rocks. Vessel-mounted laser scanners have been previously demonstrated to be effective tools for this task. However, the use of expensive survey-grade laser scanners for this shoreline survey requirement has been considered by United States charting authorities to be cost prohibitive. In this work, an in-depth performance evaluation of the Velodyne VLP-16 system, a low-cost industrial-grade mobile laser scanner, was conducted to characterize its performance. The VLP-16’s accuracy of range estimates as …

Coordination Of Leader-Follower Multi-Agent System With Time-Varying Objective Function, Zalan Mark Fabian

Master's Theses and Capstones

This thesis aims to introduce a new framework for the distributed control of multi-agent systems with adjustable swarm control objectives. Our goal is twofold: 1) to provide an overview to how time-varying objectives in the control of autonomous systems may be applied to the distributed control of multi-agent systems with variable autonomy level, and 2) to introduce a framework to incorporate the proposed concept to fundamental swarm behaviors such as aggregation and leader tracking. Leader-follower multi-agent systems are considered in this study, and a general form of time-dependent artificial potential function is proposed to describe the varying objectives of the …

Applications Of Machine Learning And Computer Vision For Smart Infrastructure Management In Civil Engineering, Shounak Mitra

Master's Theses and Capstones

Machine Learning and Computer Vision are the two technologies that have innovative applications in diverse fields, including engineering, medicines, agriculture, astronomy, sports, education etc. The idea of enabling machines to make human like decisions is not a recent one. It dates to the early 1900s when analogies were drawn out between neurons in a human brain and capability of a machine to function like humans. However, major advances in the specifics of this theory were not until 1950s when the first experiments were conducted to determine if machines can support artificial intelligence. As computation powers increased, in the form of …

The Paladin Suite: Multifaceted Characterization Of Whole Metagenome Shotgun Sequences, Anthony Stephen Westbrook

Master's Theses and Capstones

Whole metagenome shotgun sequencing is a powerful approach for assaying many aspects of microbial communities, including the functional and symbiotic potential of each contributing community member. The research community currently lacks tools that efficiently align DNA reads against protein references, the technique necessary for constructing functional profiles. This thesis details the creation of PALADIN – a novel modification of the Burrows-Wheeler Aligner that provides orders-of-magnitude improved efficiency by directly mapping in protein space. In addition to performance considerations, utilizing PALADIN and associated tools as the foundation of metagenomic pipelines also allows for novel characterization and downstream analysis.

The accuracy and …

Phylogenetic And Phylogeographic Analyses Reveal A Species Complex In The Estuarine Nudibranch Tenellia Adspersa, Amanda Sobel

Master's Theses and Capstones

Until recently, the nudibranch genus Tenellia (Nudibranchia: Fionidae) was thought to include a single or group of species restricted to temperate estuarine waters. Given the addition of numerous other species from recent studies, the genus now encompasses species from polar, temperate, and tropical oceans from oceanic to estuarine salinities. One such fionid, Tenellia adspersa, is found in temperate estuarine waters globally and its presence is ecologically important as its congeners are capable of decimating colonies of their hydroid prey within a single generation (approx. 20-60 days). The literature is historically vague and conflicted on the morphology, taxonomy, and geographic distribution …

Comparative Spectral Analysis Of Flexible Structure Models: The Euler-Bernoulli Beam Model, The Rayleigh Beam Model, And The Timoshenko Beam Model, Anhhong Rose Nguyen

Master's Theses and Capstones

We derive herein approximate spectra for three dierent models of transversely vibrating, beams. Each model consists of a system of partial dierential equations (PDEs) with various, boundary conditions. The three models that we consider are the Euler-Bernoulli model, the, Rayleigh model, and the Timoshenko model. We rst discuss a brief history of the models, before delving into obtaining the spectral equations for each beam model under dierent, boundary conditions. Lastly, we present asymptotic approximations of some of the various, spectral equations we found from each model.

Enhanced In Service Condition Assessment Of Bridges Using Gopro® Cameras, Travis Manning

Master's Theses and Capstones

Condition assessment of in-service structures, is highly depending on subjective visual inspections. While technology exists to collect objective measurements related to structural response, these techniques are costly in terms of equipment and field setup, often requiring lane closure and special equipment for sensor installation. This thesis aims to investigate cost-effective and efficient non-contact methods of structural response measurement. Digital Image Correlation (DIC) can be an effective measurement technique for displacement and strain in 2D and 3D applications. With any experiment, test setup is vital to ensure collection of accurate measurements. Also, the methods of data collection must be appropriate for …

Critical Shear Stress Estimates For Sunken Alberta Bitumen In An Annular Flume, Ian P. Gaudreau

Master's Theses and Capstones

Under certain environmental conditions and depending on its specific gravity, spilled oil has the ability to sink to the bottom of a water body (e.g., lake, river, ocean) (i.e., sunken oil). Once there, it can be difficult to predict the sunken oil’s fate and transport, making response efforts challenging. The Office of Response and Restoration (ORR) of the National Oceanic and Atmospheric Administration (NOAA) currently uses mathematical models in an attempt to better predict the movement of spilled oil. However, mathematical models cannot be simulative of the predicted trajectory if the physical or chemical properties of the oil are unknown, …

Srs Feature: Two Stars From The Other Side Of The Globe Explore Globe To Chart Their Futures, C. Ralph Adler, Globe U.S. Coordination Office

Publications and Media

No abstract provided.

Srs Feature: For Globe Teacher Diana Johns, Every Day Is Earth Day, C. Ralph Alder, Globe U.S. Coordination Office

Publications and Media

No abstract provided.

Supporting Protocol: Determining Scale Calculating Area, Nh Globe Carbon Cycle Protocol Team

Carbon

No abstract provided.

Protocol - Nonstandard: Site Set-Up, Nh Globe Carbon Cycle Protocol Team

Carbon

No abstract provided.

Supporting Protocol: Calculating Npp, Nh Globe Carbon Cycle Protocol Team

Carbon

No abstract provided.

Supporting Protocol: Tree Biomass Carbon Analysis, Nh Globe Carbon Cycle Protocol Team

Carbon

No abstract provided.

Learning Activity - Mini: Pencil Carbon, Nh Globe Carbon Cycle Protocol Team

Carbon

No abstract provided.