11,096 research outputs found

    Steady, oscillatory, and unsteady subsonic Aerodynamics, production version 1.1 (SOUSSA-P1.1). Volume 2: User/programmer manual

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    A user/programmer manual for the computer program SOUSSA P 1.1 is presented. The program was designed to provide accurate and efficient evaluation of steady and unsteady loads on aircraft having arbitrary shapes and motions, including structural deformations. These design goals were in part achieved through the incorporation of the data handling capabilities of the SPAR finite element Structural Analysis computer program. As a further result, SOUSSA P possesses an extensive checkpoint/ restart facility. The programmer's portion of this manual includes overlay/subroutine hierarchy, logical flow of control, definition of SOUSSA P 1.1 FORTRAN variables, and definition of SOUSSA P 1.1 subroutines. Purpose of the SOUSSA P 1.1 modules, input data to the program, output of the program, hardware/software requirements, error detection and reporting capabilities, job control statements, a summary of the procedure for running the program and two test cases including input and output and listings are described in the user oriented portion of the manual

    Further SEASAT SAR coastal ocean wave analysis

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    Analysis techniques used to exploit SEASAT synthetic aperture radar (SAR) data of gravity waves are discussed and the SEASAT SAR's ability to monitor large scale variations in gravity wave fields in both deep and shallow water is evaluated. The SAR analysis techniques investigated included motion compensation adjustments and the semicausal model for spectral analysis of SAR wave data. It was determined that spectra generated from fast Fourier transform analysis (FFT) of SAR wave data were not significantly altered when either range telerotation adjustments or azimuth focus shifts were used during processing of the SAR signal histories, indicating that SEASAT imagery of gravity waves is not significantly improved or degraded by motion compensation adjustments. Evaluation of the semicausal (SC) model using SEASAT SAR data from Rev. 974 indicates that the SC spectral estimates were not significantly better than the FFT results

    Symbolic Extraction for Estimating Analog Layout Parasitics in Layout-Aware Synthesis

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    This paper presents a new layout parasitics extraction paradigm, symbolic extraction, for use in layout-aware analog synthesis methodologies. Unlike traditional post-layout extraction, symbolic extraction extracts layout parasitics in symbolic form from parameterized layouts. As a result, parasitic values can be calculated directly from given circuit and layout parameters. In layout-aware circuit synthesis process, tasks of time-consuming layout re-gerenarion and re-extraction can be replaced by this fast parasitics calculation step. In the paper, we discuss how to integrate symbolic extraction into the existing analog design flow and how symbolic extraction can be implemented

    An Improved Approximate Consensus Algorithm in the Presence of Mobile Faults

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    This paper explores the problem of reaching approximate consensus in synchronous point-to-point networks, where each pair of nodes is able to communicate with each other directly and reliably. We consider the mobile Byzantine fault model proposed by Garay '94 -- in the model, an omniscient adversary can corrupt up to ff nodes in each round, and at the beginning of each round, faults may "move" in the system (i.e., different sets of nodes may become faulty in different rounds). Recent work by Bonomi et al. '16 proposed a simple iterative approximate consensus algorithm which requires at least 4f+14f+1 nodes. This paper proposes a novel technique of using "confession" (a mechanism to allow others to ignore past behavior) and a variant of reliable broadcast to improve the fault-tolerance level. In particular, we present an approximate consensus algorithm that requires only āŒˆ7f/2āŒ‰+1\lceil 7f/2\rceil + 1 nodes, an āŒŠf/2āŒ‹\lfloor f/2 \rfloor improvement over the state-of-the-art algorithms. Moreover, we also show that the proposed algorithm is optimal within a family of round-based algorithms

    Laser pulse annealing of ion-implanted GaAs

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    GaAs single-crystals wafers are implanted at room temperature with 400-keV Te + ions to a dose of 1Ɨ10^15 cm^ā€“2 to form an amorphous surface layer. The recrystallization of this layer is investigated by backscattering spectrometry and transmission electron microscopy after transient annealing by Q-switched ruby laser irradiation. An energy density threshold of about 1.0 J/cm^2 exists above which the layer regrows epitaxially. Below the threshold the layer is polycrystalline; the grain size increases as the energy density approaches threshold. The results are analogous to those reported for the elemental semiconductors, Si and Ge. The threshold value observed is in good agreement with that predicted by the simple model successfully applied previously to Si and Ge

    The Demand Side: Uses of Research in Child and Adolescent Mental Health Services

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    This special issue on child and adolescent mental health contains a thoughtful set of papers that address many of the challenges in bridging research and practice. These articles, however, focus predominantly on the supply side of producing research for use by a range of audiences, including practitioners, administrators and policy makers. This commentary emphasizes the importance of attending to, and better understanding, the demand side with regard to how research evidence is evaluated, understood, and utilized. Drawing from work underway at the William T. Grant Foundation, the authors argue for the need to understand three broad topics: user settings and perspectives, political, economic and social contexts, and the various uses of research. Furthermore, understanding the use of research evidence, or the demand side, is itself a topic for empirical investigation. The authors conclude that, when it comes to supplying evidence, donā€™t forget the demand side

    Effects of ambient gas density on the structure of pressure-atomizedsprays

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77110/1/AIAA-1991-690-582.pd
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