3,800 Works

"Viva Viola," Poster, 2015

Salisbury Symphony Orchestra
Poster for the October 17, 2015 performance "Viva Viola." Featured guest Rita Porfiris.

Season Brocure, 2015-2016

Salisbury Symphony Orchestra
Season brochure for the 2015-2016 concerts of the Salisbury Symphony Orchestra.

"Home for the Holidays," Program, 2015

Salisbury Symphony Orchestra
Program for the December 12, 2015 performance "Home for the Holidays." Featured guest Dominic Armstrong.

"Home for the Holidays," Poster, 2015

Salisbury Symphony Orchestra
Poster for the December 12, 2015 performance "Home for the Holidays." Featured guest Dominic Armstrong.

"Children's Space-Themed Concert," Poster, 2015

Salisbury Symphony Orchestra
Poster for the March 7, 2015 "Children's Space-Themed Concert" of the Salisbury Symphony Orchestra.

"A Broadway Star Comes Home," Poster, 2015

Salisbury Symphony Orchestra
Poster for the May 9, 2015 performance "A Broadway Star Comes Home." Featured guest Jennifer Hope Wills.

Simulation of a partially depleted absorber (PDA) photodetector

Yue Hu, Thomas F. Carruthers, Curtis R. Menyuk, Meredith N. Hutchinson, Vincent J. Urick & Keith J. Williams
We use a 2D drift-diffusion model to study the nonlinear response of a partially depleted absorber (PDA) phododetector. The model includes external loading, incomplete ionization, the Franz-Keldysh effect, and history-dependent impact ionization. It also takes into account heat flow in the device. With all these effects included, we obtain excellent agreement with experiments for the responsivity and for the harmonic power at different modulation frequencies. The role of these different physical effects is elucidated, and...

Comparison of Performance Analysis Tools for Parallel Programs Applied to CombBLAS

Wesley Collins, Daniel T. Martinez, Michael Monaghan, Alexey A. Munishkin, Ari Rapkin Blenkhorn, Jonathan S. Graf, Samuel Khuvis & John C. Linford
Performance analysis tools are powerful tools for high performance computing. By breaking down a program into how long the CPUs are taking on each process (pro- filing) or showing when events take place on a timeline over the course of running a program (tracing), a performance analysis tool can tell the programmer exactly, where the computer is running slowly. With this information, the programmer can focus on these performance "hotspots," and the code can be...

Parallelization for Fast Image Reconstruction using the Stochastic Origin Ensemble Method for Proton Beam Therapy

Fernando X Avila-Soto, Alec N. Beri, Eric Valenzuela, Abenezer Wudenhe, Jerimy Polf, Ari Rapkin Blenkhorn, Jonathan S. Graf & Samuel Khuvis
Proton beam therapy is becoming increasingly common in the eld of cancer treatment because of the advantages over other forms of radiation therapy. These advantages arise from the nite range of the proton beams, the relatively low dosage of radiation upon entering a patient, and the large spike in dose at the end of the beam range known as the Bragg peak. A new computer code has been developed that uses the stochastic origin ensemble...

Modeling Sources of Nonlinearity in a Simple p-i-n Photodetector

Yue Hu, Brian S. Marks, Curtis R. Menyuk, Vincent J. Urick & Keith J. Williams
Nonlinearity in p-i-n photodetectors leads to power generation at harmonics of the input frequency, limiting the performance of RF- photonic systems. We use one-dimensional and two-dimensional simulations of the drift-diffusion equations to determine the physical origin of the saturation in a simple heterojunction p-i-n photodetector at room temperature. Incomplete ionization, external loading, impact ionization, and the Franz–Keldysh effect are all included in the model. Impact ionization is the main source of nonlinearity at large reverse...

FCLC: Featureless Classification of Light Curves

Dennis Kuegler, Nikolaos Gianniotis & Kai Polsterer
FCLC (Featureless Classification of Light Curves) software describes the static behavior of a light curve in a probabilistic way. Individual data points are converted to densities and consequently probability density are compared instead of features. This gives rise to an independent classification which can corroborate the usefulness of the selected features.

Statistical Analysis of a Case-Control Alzheimer's Disease: A Retropective Approach with Su cient Dimension Reduction

Trevor V. Adriaanse, Meshach Hopkins, Rebecca Rachan, Subodh R. Selukar, Elias Al Najjar, Kofi P. Adragni & Nusrat Jahan
Alzheimer's Disease is a neurological disorder chiefly present in the elderly that affects functions of the brain such as memory and logic, eventually resulting in death. There is no known cure to Alzheimer's and evidence points to the possibility of a genetic link. This study analyzes microarray data from patients with Alzheimer's disease and disease-free patients in order to evaluate and determine differential gene expression patterns between the two groups. The statistical problem stemming from...

Assessing Climate Impacts on Regional Water Resources in the Midwestern US

Joseph U. Emelike, David Harper, Charlotte Z. Mann, Kwame Owusu Boaitey, Sai K. Popuri, Nagaraj K. Neerchal & Amita Mehta
It is well documented that decadal climate variability (DCV) has a signi cant impact on water resources in the Missouri River Basin (MRB). This project aims to utilize multi-decadal simulations of Global Climate Models (GCM) from the Climate Model Inter-comparison Project (CMIP5) to assess the DCV impact on water yield and stream ow over the MRB using a widely utilized hydrology and crop model known as the Soil and Water Assessment Tool (SWAT). We use...

Concurrent Solutions to Linear Systems using Hybrid CPU/GPU Nodes

Oluwapelumi Adenikinju, Julian Gilyard, Joshua Massey & Thomas Stitt
We investigate the parallel solutions to linear systems with the application focus as the global illumination problem in computer graphics. An existing CPU serial implementation using the radiosity method is given as the performance baseline where a scene and corresponding form-factor coeffcients are provided. The initial computational radiosity solver uses the basic Jacobi method with a fixed iteration count as an iterative approach to solving the radiosity linear system. We add the option of using...

FEM Convergence Studies for 2-D and 3-D Elliptic PDEs with Smooth and Non-Smooth Source Terms in COMSOL 5.1

Kourosh M. Kalayeh, Jonathan S. Graf & Matthias K. Gobbert
Numerical theory provides the basis for quanti cation on the accuracy and reliability of a FEM solution by error estimates on the FEM error vs. the mesh spacing of the FEM mesh. This paper presents techniques needed in COMSOL 5.1 to perform computational studies for an elliptic test problem in two and three space dimensions that demonstrate this theory by computing the convergence order of the FEM error. For a PDE with smooth right-hand side,...

Frequency and causes of failed MODIS cloud property retrievals for liquid phase clouds over global oceans

Hyoun Myoung Cho, Zhibo Zhang, Kerry Meyer, Matthew Lebsock, Steven Platnick, Andrew S. Ackerman, Larry Di Girolamo, Laurent C. Labonnote, Céline Cornet, Jerome Riedi & Robert E. Holz
Moderate Resolution Imaging Spectroradiometer (MODIS) retrieves cloud droplet effective radius (rₑ) and optical thickness (τ) by projecting observed cloud reflectances onto a precomputed look‐up table (LUT). When observations fall outside of the LUT, the retrieval is considered “failed” because no combination of τ and rₑ within the LUT can explain the observed cloud reflectances. In this study, the frequency and potential causes of failed MODIS retrievals for marine liquid phase (MLP) clouds are analyzed based...

Protonated heterocyclic derivatives of cyclopropane and cyclopropanone: classical species, alternate sites, and ring fragmentation

Margarida S. Miranda, Darío J.R. Duarte, Joaquim C.G. Esteves Da Silva & Joel F. Liebman
A computational study has been performed for protonated oxygen- or nitrogen-containing heterocyclic derivatives of cyclopropane and cyclopropanone. We have searched for the most stable conformations of the protonated species using density functional theory with the B3LYP functional and the 6-31G(2df,p) basis set. More accurate enthalpy values were obtained from G4 calculations. Proton affinities and gas-phase basicities were accordingly derived.

Analysis of subsurface storage and streamflow generation in urban watersheds

Aditi S. Bhaskar & Claire Welty
Subsurface storage as a regulator of streamflow was investigated as an explanation for the large proportion of pre‐event water observed in urban streams during storm events. We used multiple lines of inquiry to explore the relationship between pre‐event water proportion, subsurface storage, and streamflow under storm conditions. First, we used a three‐dimensional model of integrated subsurface and surface flow and solute transport to simulate an idealized hillslope to perform model‐based chemical hydrograph separation of stormflow....

Untangling the effects of urban development on subsurface storage in Baltimore

Aditi S. Bhaskar, Claire Welty, Reed M. Maxwell & Andrew J. Miller
The impact of urban development on surface flow has been studied extensively over the last half century, but effects on groundwater systems are still poorly understood. Previous studies of the influence of urban development on subsurface storage have not revealed any consistent pattern, with results showing increases, decreases, and negligible change in groundwater levels. In this paper, we investigated the effects of four key features that impact subsurface storage in urban landscapes. These include reduced...

Performance Studies of the Blossom V Algorithm

Changling Huang, Christopher C. Lowman, Brandon E. Osborne, Gabrielle M. Salib, Ari Rapkin Blenkhorn, Jonathan S. Graf, Samuel Khuvis, Matthias K. Gobbert, Tyler Simon & David Mountain
The Blossom V algorithm is used in graph theory to compute a perfect matching of minimum cost. We conducted performance studies on the algorithm using the maya cluster in the UMBC High Performance Computing Facility to better understand the performance capabilities and emphasize potential approaches for improvement. In the performance studies, we varied the number of nodes, graph density, and weight range for numerous graphs. For each graph, we recorded execution times and memory usage....

Spontaneous Calcium Release in Cardiac Myocytes: Store Overload and Electrical Dynamics

Amanda M. Alexander, Erin K. DeNardo, , Michael McCauley, Nicholas Rojina, Zana Coulibaly, Bradford E. Peercy & Leighton T. Izu
Heart disease is the leading cause of mortality in the United States. One cause of heart arrhythmia is calcium (Ca²⁺) mishandling in cardiac muscle cells. We adapt Izu's et al. mathematical reaction-diffusion model of calcium in cardiac muscle cells, or cardiomyocytes, [14], implemented by Gobbert [12], and analyzed in Coulibaly et al. [8] to include calcium being released from the sarcoplasmic reticulum (SR), the effects of buffers in the SR, particularly calsequestrin, and the effects...

Calcium Induced Calcium Release with Stochastic Uniform Flux Density in a Heart Cell

M. W. Brewster, J. S. Graf, X. Huang, Z. Coulibaly, M. K. Gobbert & B. E. Peercy
SummerSim '15 Proceedings of the Conference on Summer Computer Simulation

Impact of Calcium Store Overload and Electrical Dynamics on Cardiac Myocytes

Amanda M. Alexander, Erin K. DeNardo, , Michael McCauley, Nicholas Rojina, Zana Coulibaly, Bradford E. Peercy & Leighton T. Izu
The heart's main function of pumping blood to the body is a complicated process separated into two major steps. Initially, the heart is relaxed and blood flows freely into the ventricles and atria from the veins, then the atria contracts and pumps more blood to the ventricles. The atria relaxes and the inlet valves between these and the ventricles close, producing the initial thump of the heartbeat, as pressure builds while the ventricles contract. This...

Performance Evaluation of Minimum Average Deviance Estimation in High Dimensional Poisson Regression

Ely Biggs, Tessa Helble, George Jeffreys, Amit Nayak, Elias Al-Najjar, Andrew M. Raim & Kofi P. Adragni
The second most expensive part of the 2010 Decennial Census was Address Canvassing (AdCan), a eld operation to prepare the Master Address File (MAF) for census day. The MAF is a database of households in the United States maintained by the US Census Bureau and is used as a basis for the census and household surveys that it conducts. Motivated by the importance of the MAF and the cost of a large scale AdCan operation,...

Modeling Overdispersion in R

Andrew M. Raim, Nagaraj K. Neerchal & Jorge G. Morel
The book Overdispersion Models in SAS by Morel and Neerchal (2012) discusses statistical analysis of categorical and count data which exhibit overdispersion, with a focus on computational procedures using SAS. This document retraces some of the ground covered in the book, which we abbreviate throughout as OMSAS, with the objective of carrying out similar analyses in R (R Core Team, 2014). Rather than attempting to cover every example in OMSAS, we will focus on two...

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