52 research outputs found
Model-Based Matching of Line Drawings by Linear Combinations of Prototypes
We describe a technique for finding pixelwise correspondences between two images by using models of objects of the same class to guide the search. The object models are 'learned' from example images (also called prototypes) of an object class. The models consist of a linear combination ofsprototypes. The flow fields giving pixelwise correspondences between a base prototype and each of the other prototypes must be given. A novel image of an object of the same class is matched to a model by minimizing an error between the novel image and the current guess for the closest modelsimage. Currently, the algorithm applies to line drawings of objects. An extension to real grey level images is discussed
Model-Based Matching by Linear Combinations of Prototypes
We describe a method for modeling object classes (such as faces) using 2D example images and an algorithm for matching a model to a novel image. The object class models are "learned'' from example images that we call prototypes. In addition to the images, the pixelwise correspondences between a reference prototype and each of the other prototypes must also be provided. Thus a model consists of a linear combination of prototypical shapes and textures. A stochastic gradient descent algorithm is used to match a model to a novel image by minimizing the error between the model and the novel image. Example models are shown as well as example matches to novel images. The robustness of the matching algorithm is also evaluated. The technique can be used for a number of applications including the computation of correspondence between novel images of a certain known class, object recognition, image synthesis and image compression
Vortex Induced Liquid Engine
The growth of reusable space launch vehicles has led to a demand for improved rocket propulsion cooling systems which vary in degrees of complexity. Vortex Induced Liquid Engine (VILE) is a project to study and investigate cooling solutions that lead to higher engine efficiency and increased reusability for rockets. The research focuses on the design and thermal analysis to postulate a novel approach to vortex engine concepts to ensure the system\u27s functionality and reliability is augmented by the ease of production to aid the growing field of space propulsion.
CFD modeling was utilized with VILE version 1 CAD model as a proof of concept to determine if film cooling could be replaced with vortex cooling. Currently VILE is undergoing analysis for its MATLAB model and an associated version update for the CAD model. Focus is on the fuel and oxidizer feed system with all the supporting hardware for proper data collection and analysis
Integrated Spacecraft Autonomous Attitude Control (ISAAC)
The purpose of this project is to give undergraduate students an opportunity to design, manufacture, and maintain a mock spacecraft to be used as a testbed for autonomous control systems. The spacecraft is based on two previous models: the JX-01, an undergraduate built testbed, and the Asteroid Free Flyer led by NASA engineer and ERAU doctoral student, Michael Dupuis. This model includes cable improvements, Inertial Measurement Units (IMU), Light Detection and Ranging (LIDAR), and object-based state estimation to improve control stabilization. When completed, the hardware built for this project will provide undergraduates and researchers a platform with which they can test control algorithms and spacecraft component design. The results gathered from the project thus far is the building and design and controls experience between the team. After completion we will be able to obtain a properly modeled control algorithm and test it against multiple conditions. The final goal of the spacecraft is to provide the capabilities and perform experiments to test multiple methods to mitigate the effects of internal and external forces such as fuel sloshing, solar radiation, debris collision, and CG change
Integrated Spacecraft Autonomous Attitude Control (ISAAC)
The purpose of this project is to give undergraduate students an opportunity to design, manufacture, and maintain a mock spacecraft to be used as a testbed for autonomous control systems. The spacecraft is based on two previous models: the JX-01, an undergraduate built testbed, and the Asteroid Free Flyer led by NASA engineer and ERAU doctoral student, Michael Dupuis. This model includes cable improvements, Inertial Measurement Units (IMU), Light Detection and Ranging (LIDAR), and object-based state estimation to improve control stabilization. When completed, the hardware built for this project will provide undergraduates and researchers a platform with which they can test control algorithms and spacecraft component design. The results gathered from the project thus far is the building and design and controls experience between the team. After completion we will be able to obtain a properly modeled control algorithm and test it against multiple conditions. The final goal of the spacecraft is to provide the capabilities and perform experiments to test multiple methods to mitigate the effects of internal and external forces such as fuel sloshing, solar radiation, debris collision, and CG change
Short Timescale Evolution of the Polarized Radio Jet during V404 Cygni's 2015 Outburst
We present a high time resolution, multi-frequency linear polarization
analysis of Very Large Array (VLA) radio observations during some of the
brightest radio flaring (~1 Jy) activity of the 2015 outburst of V404 Cygni.
The VLA simultaneously captured the radio evolution in two bands (each with two
1 GHz base-bands), recorded at 5/7 GHz and 21/26 GHz, allowing for a broadband
polarimetric analysis. Given the source's high flux densities, we were able to
measure polarization on timescales of ~13 minutes, constituting one of the
highest temporal resolution radio polarimetric studies of a black hole X-ray
binary (BHXB) outburst to date. Across all base-bands, we detect variable,
weakly linearly polarized emission (<1%) with a single, bright peak in the
time-resolved polarization fraction, consistent with an origin in an evolving,
dynamic jet component. We applied two independent polarimetric methods to
extract the intrinsic electric vector position angles and rotation measures
from the 5 and 7 GHz base-band data and detected a variable intrinsic
polarization angle, indicative of a rapidly evolving local environment or a
complex magnetic field geometry. Comparisons to the simultaneous,
spatially-resolved observations taken with the Very Long Baseline Array at 15.6
GHz, do not show a significant connection between the jet ejections and the
polarization state.Comment: 24 pages, 9 figures, accepted by MNRA
Custom Integrated Circuits
Contains reports on nine research projects.Analog Devices, Inc.International Business Machines CorporationJoint Services Electronics Program Contract DAAL03-89-C-0001U.S. Air Force - Office of Scientific Research Contract AFOSR 86-0164BDuPont CorporationNational Science Foundation Grant MIP 88-14612U.S. Navy - Office of Naval Research Contract N00014-87-K-0825American Telephone and TelegraphDigital Equipment CorporationNational Science Foundation Grant MIP 88-5876
Comparative Genomic Characterization of Francisella tularensis Strains Belonging to Low and High Virulence Subspecies
Tularemia is a geographically widespread, severely debilitating, and occasionally lethal disease in humans. It is caused by infection by a gram-negative bacterium, Francisella tularensis. In order to better understand its potency as an etiological agent as well as its potential as a biological weapon, we have completed draft assemblies and report the first complete genomic characterization of five strains belonging to the following different Francisella subspecies (subsp.): the F. tularensis subsp. tularensis FSC033, F. tularensis subsp. holarctica FSC257 and FSC022, and F. tularensis subsp. novicida GA99-3548 and GA99-3549 strains. Here, we report the sequencing of these strains and comparative genomic analysis with recently available public Francisella sequences, including the rare F. tularensis subsp. mediasiatica FSC147 strain isolate from the Central Asian Region. We report evidence for the occurrence of large-scale rearrangement events in strains of the holarctica subspecies, supporting previous proposals that further phylogenetic subdivisions of the Type B clade are likely. We also find a significant enrichment of disrupted or absent ORFs proximal to predicted breakpoints in the FSC022 strain, including a genetic component of the Type I restriction-modification defense system. Many of the pseudogenes identified are also disrupted in the closely related rarely human pathogenic F. tularensis subsp. mediasiatica FSC147 strain, including modulator of drug activity B (mdaB) (FTT0961), which encodes a known NADPH quinone reductase involved in oxidative stress resistance. We have also identified genes exhibiting sequence similarity to effectors of the Type III (T3SS) and components of the Type IV secretion systems (T4SS). One of the genes, msrA2 (FTT1797c), is disrupted in F. tularensis subsp. mediasiatica and has recently been shown to mediate bacterial pathogen survival in host organisms. Our findings suggest that in addition to the duplication of the Francisella Pathogenicity Island, and acquisition of individual loci, adaptation by gene loss in the more recently emerged tularensis, holarctica, and mediasiatica subspecies occurred and was distinct from evolutionary events that differentiated these subspecies, and the novicida subspecies, from a common ancestor. Our findings are applicable to future studies focused on variations in Francisella subspecies pathogenesis, and of broader interest to studies of genomic pathoadaptation in bacteria
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