48 research outputs found

    The Diagnostic Potential of Transition Region Lines under-going Transient Ionization in Dynamic Events

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    We discuss the diagnostic potential of high cadence ultraviolet spectral data when transient ionization is considered. For this we use high cadence UV spectra taken during the impulsive phase of a solar flares (observed with instruments on-board the Solar Maximum Mission) which showed excellent correspondence with hard X-ray pulses. The ionization fraction of the transition region ion O V and in particular the contribution function for the O V 1371A line are computed within the Atomic Data and Analysis Structure, which is a collection of fundamental and derived atomic data and codes which manipulate them. Due to transient ionization, the O V 1371A line is enhanced in the first fraction of a second with the peak in the line contribution function occurring initially at a higher electron temperature than in ionization equilibrium. The rise time and enhancement factor depend mostly on the electron density. The fractional increase in the O V 1371A emissivity due to transient ionization can reach a factor of 2--4 and can explain the fast response in the line flux of transition regions ions during the impulsive phase of flares solely as a result of transient ionization. This technique can be used to diagnostic the electron temperature and density of solar flares observed with the forth-coming Interface Region Imaging Spectrograph.Comment: 18 pages, 6 figure

    Properties and structure of the analytic singular value decomposition

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    We investigate the singular value decomposition (SVD) of a rectangular matrix A(z) of functions that are analytic on an annulus that includes at least the unit circle. Such matrices occur, e.g., as matrices of transfer functions representing broadband multiple-input multiple-output systems. Our analysis is based on findings for the analytic SVD applicable to continuous time systems, and on the analytic eigenvalue decomposition. Using these, we establish two potentially overlapping cases where analyticity of the SVD factors is denied. Firstly, from a structural point of view, multiplexed systems require oversampling by the multiplexing factor in order to admit an analytic solution. Secondly, from an algebraic perspective, we state under which condition spectral zeroes of any singular value require additional oversampling by a factor of two if an analytic solution is to be found. In all other cases, an analytic matrix admits an analytic SVD, whereby the singular values are unique up to a permutation, and the left- and right-singular vectors are coupled through a joint ambiguity w.r.t.~an arbitrary allpass function. We demonstrate how some state-of-the-art polynomial matrix decomposition algorithms approximate this solution, motivating the need for dedicated algorithms

    Delinquency and reputational orientations of adolescent at-risk and not-at-risk males and females

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    This research investigated differences in delinquent activities and the reputational orientations of at-risk and not-at-risk male and female adolescents. Initially, we sought to establish that adolescent males and females differed in these respects. This was found to be the case: males (n = 722) scored significantly higher than females (n = 738) on seven self-reported delinquency variables and on eight reputation enhancement variables pertaining to social deviance, non-conforming reputation, and power/evaluation private identity. When a sample of 31 at-risk females was subsequently pair-wise age matched with 31 not-at-risk females, at-risk females scored significantly higher on all delinquency variables other than school misdemeanors. These at-risk females also scored significantly higher on four reputation enhancement variables relating to social deviance and non-conformity. Given that at-risk females did not differ from their not-at-risk counterparts in level of involvement in school misdemeanors, we sought to determine whether this was also the case for at-risk and not-at-risk males. An age-matched sample of 91 pairs revealed that at-risk males reported significantly higher involvement than not-at-risk males in all aspects of delinquency, including school misdemeanors. They also sought a more non-conforming reputation. To explore the relationships between delinquency and reputation enhancement, a canonical correlation analysis was performed. All findings are discussed in the light of reputation enhancement theory. © 2008 Taylor & Franci

    BIT-LEVEL SYSTOLIC ARRAY CIRCUIT FOR MATRIX VECTOR MULTIPLICATION.

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    Presented at the 2011 Robotics: Science and Systems Conference VII (RSS), 27-30 June 2011, Los Angeles, CA.We present and analyze the Motion Grammar: a novel unified representation for task decomposition, perception, planning, and control that provides both fast online control of robots in uncertain environments and the ability to guarantee completeness and correctness. The grammar represents a policy for the task which is parsed in real-time based on perceptual input. Branches of the syntax tree form the levels of a hierarchical decomposition, and the individual robot sensor readings are given by tokens. We implement this approach in the interactive game of Yamakuzushi on a physical robot resulting in a system that repeatably competes with a human opponent in sustained gameplay for the roughly six minute duration of each match

    Systolic and Wavefront Arrays

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    Editorial - Nonlinear and non-Gaussian signal processing

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