The Low Back Merger in Miami

The last major study of the low-back merger in Miami, Florida, was Labov, Ash, and Boberg’s (2006) work for the Atlas of North American English (ANAE). In that influential work, Labov et al. found the low-back merger to be in transition in Miami. However, the ANAE was based on Telsur data, the most recent of which was collected nearly 10 years ago. Presumably, since that time, the low-back merger has progressed in Miami towards a full merger. This study focuses on the progress of the low back merger in a Miami speech community. Eighteen participants were interviewed. Interviews consisted of a word list with 8 words containing vowels of the /o/ word-class, and 8 others containing vowels of the /oh/ word-class, as well a short reading passage and a commutation test. Acoustic analysis focused on the words in the word list, and a cursory examination of the passage data was in agreement with the findings from the word list pronunciations. The data from the word lists was analyzed and the F1 and F2 of /o/ and /oh/ vowels were averaged for comparison. Vowels preceding [r] and [+nasal] obstruents were excluded from analysis, due to their significant effect on formants. This exclusion should also serve to make any results suggesting movement towards a merger more compelling, because ANAE data found that 2 of 5 Miami residents interviewed had a merger only before nasals. Keeping analysis within the listed restraints, it appears that the low-back merger has continued towards fruition in Miami. To determine the presence of a merger, techniques were replicated from an earlier study on near-mergers (Bowie 2001), using t-tests to compare the averages of the first two formants of the /o/ and /oh/ vowels for each speaker. Initial analysis suggests that 13 of 18 interviewees have a low-back merger in perception, and 11 of 18 have a merger in both production and perception. This pattern follows predictable patterns of merger proliferation, suggesting that merger is continuing to spread among Miami residents and that the city and surrounding areas continue to diverge from traditional Southern dialect characteristics

Robot Simulation Analysis

• Simulate virtual robot for test and analysis • Analyze SLAM solutions using ROS • Assemble a functional Turtlebot • Emphasize projects related to current research trajectories for NASA, and general robotics application

Validation Study of Image Recognition Algorithms

Developments in machine learning in recent years have created opportunities that previously never existed. One such field with an explosion of opportunity is image recognition, also known as computer vision; the process in which a machine analyzes a digital image. In order for a machine to ‘see’ as a human does, it must break down the image in a process called image segmentation. The way the machine goes about doing this is important, and many algorithms exist to determine just how a machine will decide to group the pixels in an image. This research is a validation study of related papers on image segmentation algorithms for machine learning. Algorithms for this study will be written in Python and tested on three different hardware environments: a laptop, a desktop, and a server. Many fields have great use for computer vision, and its improvement is a good sign that more possibilities will open up with its application. Additionally, this study opens opportunities for students to see sophisticated code first hand. This research was funded in part by the Dr. Snowden Memorial Scholarship with the NASA OKLAHOMA Space Grant Consortium. This material is based upon work supported by the National Aeronautics and Space Administration issued through the Oklahoma Space Grant Consortium

ALPyNA: Acceleration of Loops in Python for Novel Architectures

We present ALPyNA, an automatic loop parallelization framework for Python, which analyzes data dependences within nested loops and dynamically generates CUDA kernels for GPU execution. The ALPyNA system applies classical dependence analysis techniques to discover and exploit potential parallelism. The skeletal structure of the dependence graph is determined statically (if possible) or at runtime; this is combined with type and bounds information discovered at runtime, to auto-generate high-performance kernels for offload to GPU. We demonstrate speedups of up to 1000x relative to the native CPython interpreter across four array-intensive numerical Python benchmarks. Performance improvement is related to both iteration domain size and dependence graph complexity. Nevertheless, this approach promises to bring the benefits of manycore parallelism to application developers

Profiling the National Center for Atmospheric Research’s Weather Research and Forecasting Model

This project employs High Performance Computing (HPC) to analyze the National Center for atmospheric research’s Weather, Research, and Forecasting Model (NCAR-WRF). Once an appropriate profiler is found, it will be used to determine if NCAR-WRF is compute bound, meaning its speed is determined by the power of its processors, or memory bound, meaning that the wall clock time is determined by the amount of available memory

Corona initiation criteria in air and Martian atmosphere

In this work, the focus is on plasma discharge produced between two electrodes with a high potential difference, resulting in ionization of the neutral gas particles and creating a current in the gas medium. This process, when done at low current and low temperature can create corona and “glow” discharges, which can be observed as a luminescent, or “glow,” emission. The parallel plate geometry used in Paschen theory is particularly well suited to model experimental laboratory scenario. However, it is limited in its applicability to lightning rods and power lines [Moore et al., 2000]. Previous works on the effect of the electrode geometry such as Franklin’s sharp tip and Moore et al.’s rounded tip fundamentally differ in the radius of curvature of the upper end of the rod.To investigate the effect of localized electric field due to conductor radius the classic Cartesian geometry will be expanded into spherical and cylindrical geometries. In a spherical case, a small radius effectively represents a sharp tip rod, while larger, centimeter-scale radius represents a rounded or blunted tip; in a cylindrical case, a small radius would correspond to a thin wire. Utilizing Townsend’s equation for corona discharge, the estimation of a critical radius and minimum breakdown voltage that allows ionization of neutral gas and formation of a glow corona around an electrode in air is made from these models. Additionally, thethe influence of the gas in which the discharge develops is explored. Using Bolsig+, a numerical solver for the Boltzmann equation, to calculate critical electric fields necessary to initiate corona discharge in gasses with varying composition [Hagelaar and Pitchford, 2005]. This allows the exploration of the feasibility of a glow corona on other planetary bodies such as Mars. The breakdown criterion both numerically and analytically will be presented with simplified formulae per each geometry and gas mixture

AMUSE-Virgo I. Super-massive black holes in low-mass spheroids

We present the first results from the AGN Multiwavelength Survey of Early-type galaxies in the Virgo cluster (AMUSE-Virgo). This large program targets 100 early-type galaxies with the Advanced CCD Imaging Spectrometer on board the Chandra X-ray Observatory and the Multi-band Imaging Photometer on board the Spitzer Space Telescope, with the aim of providing an unbiased census of low-level super-massive black hole (SMBH) activity in the local universe. Here we report on the Chandra observations of the first 16 targets, and combine them with results from archival data of another, typically more massive, 16 targets. Point-like X-ray emission from a position coincident with the optical nucleus is detected in 50% of the galaxies (down to our completeness limit of ~4E+38 erg/sec). Two of the X-ray nuclei are hosted by galaxies (VCC1178=N4464 and VCC1297=N4486B) with absolute B magnitudes fainter than -18, where nuclear star clusters are known to become increasingly common. After carefully accounting for possible contamination from low mass X-ray binaries, we argue that the detected nuclear X-ray sources are most likely powered by low-level accretion on to a SMBH, with a <11% chance contamination in VCC1178, where a star cluster is barely resolvable in archival Hubble Space Telescope images. Based on black hole mass estimates from the global properties of the host galaxies, all the detected nuclei are highly sub-Eddington, with luminosities in the range -8.4<log(L_0.3-10keV/L_Edd)<-5.9. The incidence of nuclear X-ray activity increases with the stellar mass M_star of the host galaxy: only between 3-44% of the galaxies with M_star<1E+10 M_Sun harbor an X-ray active SMBH. The fraction rises to between 49-87% in galaxies with stellar mass above 1E+10 M_Sun (at the 95% confidence level).Comment: Revised version, accepted by Ap