2,939 research outputs found
HPC Made Easy: Using Docker to Distribute and Test Trilinos
Virtualization is an enticing option for computer science research given its ability to provide repeatable, standardized environments, but traditional virtual machines have too much overhead cost to be practical. Docker, a Linux-based tool for operating-system level virtualization, has been quickly gaining popularity throughout the computer science field by touting a virtualization solution that is easily distributable and more lightweight than virtual machines. This thesis aims to explore if Docker is a viable option for conducting virtualized research by evaluating the results of parallel performance tests using the Trilinos project
Flight investigation of V/STOL height- control requirements for hovering and low- speed flight under visual conditions
Flight test of V/STOL height control requirement for hovering and low speed flight under visual condition
University Student-Athletes’ Experiences of Facilitators and Barriers to Contribution: A Narrative Account
University student-athletes’ contributions in the form of volunteering, community engagement, and civic engagement have been the subject of recent research; however, no studies have specifically examined the factors that facilitate or serve as barriers to contribution in this population. As such, the purpose of this study is to explore the facilitators and barriers relating to university student-athletes’ contributions. Individual semi-structured interviews were conducted with eight university student-athletes (two males, six females) between 18 and 21 years of age (M = 19.25) from two Canadian universities. The analysis led to the identification of two qualitatively distinct profiles regarding how facilitators and barriers to contributions were experienced: (a) the first-year student-athletes and (b) the sustained contributors. Although the participants in each profile identified teammates, coaches, and athletics department staff as facilitators to contribution, they differed in their interpretation of how these individuals facilitated contributions. First-year student-athletes were more reliant than sustained contributors on having facilitators create contribution opportunities. The profiles also differed in regards to how time constraints were overcome. First-year student-athletes utilized less complex, individual time-management strategies, while sustained contributors collaboratively made use of more advanced time-management strategies to optimize their time
\u3cem\u3eToxic Bones\u3c/em\u3e: The Burdens of Discovering Human Remains in West Virginia\u27s Abandoned and Unmarked Graves
This article pulls up and highlights a land use restriction, or financial burden, imposed upon West Virginia private real estate owners who inadvertently uncover human skeletal remains in unmarked graves on their property. In this state, those coming across human bones that historians and archaeologists eventually deem have no historical or archeological significance have a choice—pay the costs to have the bones removed and reinterred or cover the bones and use the property only as a cemetery in perpetuity. This burden becomes more acute when comparing West Virginia’s law to those of other states that require government officials, at public expense, to remove and re-bury discovered bones in a state cemetery set aside for that purpose. This leads one to consider whether West Virginia’s law, as implemented, constitutes a Fifth Amendment “taking” of private property for public use without just compensation, that is, whther the state is imposing upon private property owners a de facto cemetery for the remains of unknown and insignificant persons.
It may be helpful to point out what this Article is not about. This Article does not address bones located in marked and designated burial sites, such as established cemeteries. It also does not take up the uncovering of Native American remains, or for that matter, any other remains that the scientific and cultural communities ultimately determine are historically or archeologically significant.
Rather, this Article focuses on the inadvertent discovery of the bones of people who, through the passage of time, have been forgotten or abandoned, and who historians and archaeologists deem unremarkable
Reciprocity relationships in vector acoustics and their application to vector field calculations
The article of record as published may be found at 10.1121/1.4996458The reciprocity equation commonly stated in underwater acoustics relates pressure fields and monopole sources. It is often used to predict the pressure measured by a hydrophone for multiple source locations by placing a source at the hydrophone location and calculating the field everywhere for that source. A similar equation that governs the orthogonal components of the particle velocity field is needed to enable this computational method to be used for acoustic vector sensors. This paper derives a general reciprocity equation that accounts for both monopole and dipole sources. This vector-scalar reciprocity equation can be used to calculate individual components of the received vector field by altering the source type used in the propagation calculation. This enables a propagation model to calculate the received vector field components for an arbitrary number of source locations with a single model run for each vector field component instead of requiring one model run for each source location. Application of the vector-scalar reciprocity principle is demonstrated with analytic solutions for a range-independent environment and with numerical solutions for a range-dependent environment using a parabolic equation model
Physics-based characterization of soft marine sediments using vector sensors
In a 2007 experiment conducted in the northern North Sea, observations of a low-frequency seismo-acoustic wave field with a linear horizontal array of vector sensors located on the seafloor revealed a strong, narrow peak around 38 Hz in the power spectra and a presence of multi-mode horizontally and vertically polarized interface waves with phase speeds between 45 and 350 m/s. Dispersion curves of the interface waves exhibit piece-wise linear dependences between the logarithm of phase speed and logarithm of frequency with distinct slopes at large and small phase speeds, which suggests a seabed with a power-law shear speed dependence in two distinct sediment layers. The power spectrum peak is interpreted as a manifestation of a seismo-acoustic resonance. A simple geoacoustic model with a few free parameters is derived that quantitatively reproduces the key features of the observations. This article's approach to the inverse problem is guided by a theoretical analysis of interface wave dispersion and resonance reflection of compressional waves in soft marine sediments containing two or more layers of different composition. Combining data from various channels of the vector sensors is critical for separating waves of different polarizations and helps to identify various arrivals, check consistency of inversions, and evaluate sediment density
Energy From The Skies: Empowering Future Generations
The article discusses the development of photovoltaic technology. The first account of the use of solar power during war in western civilization was in the second century B.C. during the battle of Syracuse with Archimedes\u27 famed Death Ray. In the late 1800s and early 1900s many advances occurred including the invention of solar-powered engines, the discovery of the photoconductivity of selenium and its ability to produce electricity when exposed to light, and the construction of the first solar cells from selenium wafers. Photovoltaic technology was born in the U.S. in 1954 when Daryl Chapin, Calvin Fuller, and Gerald Pearson developed the silicon photovoltaic cell at Bell Labs. The different types of photovoltaic manufacturing processes are discussed
Motion-base simulator study of control of an externally blown flap STOL transport aircraft after failure of an outboard engine during landing approach
A moving-base simulator investigation of the problems of recovery and landing of a STOL aircraft after failure of an outboard engine during final approach was made. The approaches were made at 75 knots along a 6 deg glide slope. The engine was failed at low altitude and the option to go around was not allowed. The aircraft was simulated with each of three control systems, and it had four high-bypass-ratio fan-jet engines exhausting against large triple-slotted wing flaps to produce additional lift. A virtual-image out-the-window television display of a simulated STOL airport was operating during part of the investigation. Also, a simple heads-up flight director display superimposed on the airport landing scene was used by the pilots to make some of the recoveries following an engine failure. The results of the study indicated that the variation in visual cues and/or motion cues had little effect on the outcome of a recovery, but they did have some effect on the pilot's response and control patterns
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