6,313 research outputs found
Evaluation of Background Subtraction Algorithms with Post-processing
Processing a video stream to segment foreground objects from the background is a critical first step in many computer vision applications. Background subtraction (BGS) is a commonly used technique for achieving this segmentation. The popularity of BGS largely comes from its computational efficiency, which allows applications such as humancomputer interaction, video surveillance, and traffic monitoring to meet their real-time goals. Numerous BGS algorithms and a number of postprocessing techniques that aim to improve the results of these algorithms have been proposed. In this paper, we evaluate several popular, state-of-the-art BGS algorithms and examine how post-processing techniques affect their performance. Our experimental results demonstrate that post-processing techniques can significantly improve the foreground segmentation masks produced by a BGS algorithm. We provide recommendations for achieving robust foreground segmentation based on the lessons learned performing this comparative study. 1
Enhancing the Performance of the T-Peel Test for Thin and Flexible Adhered Laminates
Symmetrically bonded thin and flexible T-peel specimens, when tested on
vertical travel machines, can be subject to significant gravitational loading;
with the associated asymmetry and mixed-mode failure during peeling. This can
cause erroneously high experimental peel forces to be recorded which leads to
uncertainty in estimating interfacial fracture toughness and failure mode. To
overcome these issues, a mechanical test fixture has been designed for use with
vertical test machines, that supports the unpeeled portion of the test specimen
and suppresses parasitic loads due to gravity from affecting the peel test. The
mechanism, driven by the test machine cross-head, moves at one-half of the
velocity of the cross-head such that the unpeeled portion always lies in the
plane of the instantaneous center of motion. Several specimens such as bonded
polymeric films, laminates, and commercial tapes were tested with and without
the fixture, and the importance of the proposed T-peel procedure has been
demonstrated
Coronal radiation belts
The magnetic field of the solar corona has a large-scale dipole character,
which maps into the bipolar field in the solar wind. Using standard
representations of the coronal field, we show that high-energy ions can be
trapped stably in these large-scale closed fields. The drift shells that
describe the conservation of the third adiabatic invariant may have complicated
geometries. Particles trapped in these zones would resemble the Van Allen Belts
and could have detectable consequences. We discuss potential sources of trapped
particles
Tuning the Kondo effect with a mechanically controllable break junction
We study electron transport through C60 molecules in the Kondo regime using a
mechanically controllable break junction. By varying the electrode spacing, we
are able to change both the width and height of the Kondo resonance, indicating
modification of the Kondo temperature and the relative strength of coupling to
the two electrodes. The linear conductance as a function of T/T_K agrees with
the scaling function expected for the spin-1/2 Kondo problem. We are also able
to tune finite-bias Kondo features which appear at the energy of the first C60
intracage vibrational mode.Comment: 4 pages with 4 figure
Composite vortex model of the electrodynamics of high- superconductor
We propose a phenomenological model of vortex dynamics in which the vortex is
taken as a composite object made of two components: the vortex current which is
massless and driven by the Lorentz force, and the vortex core which is massive
and driven by the Magnus force. By combining the characteristics of the
Gittleman-Rosenblum model (Phys. Rev. Lett. {\bf 16}, 734 (1966)) and Hsu's
theory of vortex dynamics (Physica {\bf C 213},305 (1993)), the model provides
a good description of recent far infrared measurements of the
magneto-conductivity tensor of superconducting YBaCuO
films from 5 cm to 200 cm.Comment: LaTex file (12 pages) + 3 Postscript figures, uuencoded. More
information on this paper, please check
http://www.wam.umd.edu/~lihn/newmodel
Sorting Nexin 1 Down-Regulation Promotes Colon Tumorigenesis
PURPOSE: Colon cancer is one of the most common human malignancies, yet studies have only begun to identify the multiple mechanisms that underlie the development of this tumor. In this study, we have identified a novel mechanism, dysregulation of endocytic sorting, which promotes colon cancer development. EXPERIMENTAL DESIGN: Immunohistochemical and microarray analyses were done on human colon cancer tissue specimens to determine the levels of one endocytic protein, sorting nexin 1 (SNX1). SW480 cells, a human colon cancer cell line that retains a relatively high level of SNX1 expression, were used to assess the effects of down-regulating this protein by small hairpin RNA. Activation of signal transduction cascades was evaluated in these cells using Western blotting, and multiple functional assays were done. RESULTS: We determined by immunohistochemistry that the level of SNX1 was significantly down-regulated in 75% of human colon cancers. In corroborative studies using microarray analysis, SNX1 message was significantly decreased (log(2) ratio less than -1) for 8 of 19 colon carcinomas. Cell lines with reduced SNX1 levels showed increased proliferation, decreased apoptosis, and decreased susceptibility to anoikis. They also showed increased activation of epidermal growth factor receptor and extracellular signal-regulated kinase 1/2 in response to epidermal growth factor. This increased activation was abolished by inhibition of endocytosis. CONCLUSIONS: These data suggest that loss of SNX1 may play a significant role in the development and aggressiveness of human colon cancer, at least partially through the mechanism of increased signaling from endosomes. Further, these findings suggest that dysregulation of endocytic proteins may represent a new paradigm in the process of carcinogenesis.Fil: Nguyen, Lananh N.. University of Washington; Estados UnidosFil: Holdren, Matthew S.. University of Washington; Estados UnidosFil: Nguyen, Anthony P.. Baylor College of Medicine; Estados UnidosFil: Furuya, Momoko H.. University of Washington; Estados UnidosFil: Bianchini, Michele. Fundación Cáncer. Centro de Investigaciones Oncológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Levy, Estrella Mariel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundación Cáncer. Centro de Investigaciones Oncológicas; ArgentinaFil: Mordoh, Jose. Fundación Cáncer. Centro de Investigaciones Oncológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Liu, Annie. University of Washington; Estados UnidosFil: Guncay, Gabriela D.. University of Washington; Estados UnidosFil: Campbell, Jean S.. University of Washington; Estados UnidosFil: Parks, W. Tony. University of Washington; Estados Unido
Measurement of the Far Infrared Magneto-Conductivity Tensor of Superconducting YBaCuO Thin Films
We report measurements of the far infrared transmission of superconducting
YBaCuO thin films from 5 cm to 200 cm in
fields up to 14. A Kramers-Kronig analysis of the magneto-transmission
spectrum yields the magneto-conductivity tensor. The result shows that the
magneto-conductivity of YBaCuO is dominated by three
terms: a London term, a low frequency Lorentzian ( 3 cm) of width 10 cm and a finite frequency Lorentzian of
width 17 cm at 24 cm in the hole
cyclotron resonance active mode of circular polarization.\\Comment: Revised LaTex file (12 pages) + 4 Postscript figures, uuencoded. In
response to referees' comments, we refined the paper a lot; we encourage you
to download this revised versio
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Thorium Energy Futures
The potential for thorium as an alternative or supplement to uranium in fission power generation has long been recognised, and several reactors, of various types, have already operated using thorium-based fuels. Accelerator Driven Subcritical (ADS) systems have benefits and drawbacks when compared to conventional critical thorium reactors, for both solid and molten salt fuels. None of the four options – liquid or solid, with or without an accelerator – can yet be rated as better or worse than the other three, given today's knowledge. We outline the research that will be necessary to lead to an informed choice
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