12,260 research outputs found

    A Model for the Effectiveness of Aircraft Alerting and Warning Systems

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    The effectiveness of an alerting system with a single alert was analyzed. The pilot's decision behavior is modeled by the theory of signal detection and therefore accounts for different strengths of cross check information and different pilot criteria. The model includes the effects of the alerting and warning system (CAWS) error rate; the pilot's past experience with the CAWS accuracy; his reliance on the CAWS rather than independent monitoring; missed alerts; and adoption of a minimum error or Neyman-Pearson objective rather than minimum cost objective. It is showwn that for rare events: (1) the expected cost is greatly increased if the pilot ignores the a posteriori information in the existence of an alert; (2) the expected cost is insensitive to CAWS Type 1 errors; and (3) the expected cost is sensitive to CAWS type 2 errors only when the cross check information is ambiguous

    Evaluation of the effects of space environment exposure on index of refraction and extinction coefficients of Apollo window materials

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    Temperature and radiation effects on index of refraction and extinction coefficients of Apollo window material

    Domain structure of epitaxial Co films with perpendicular anisotropy

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    Epitaxial hcp Cobalt films with pronounced c-axis texture have been prepared by pulsed lased deposition (PLD) either directly onto Al2O3 (0001) single crystal substrates or with an intermediate Ruthenium buffer layer. The crystal structure and epitaxial growth relation was studied by XRD, pole figure measurements and reciprocal space mapping. Detailed VSM analysis shows that the perpendicular anisotropy of these highly textured Co films reaches the magnetocrystalline anisotropy of hcp-Co single crystal material. Films were prepared with thickness t of 20 nm < t < 100 nm to study the crossover from in-plane magnetization to out-of-plane magnetization in detail. The analysis of the periodic domain pattern observed by magnetic force microscopy allows to determine the critical minimum thickness below which the domains adopt a pure in-plane orientation. Above the critical thickness the width of the stripe domains is evaluated as a function of the film thickness and compared with domain theory. Especially the discrepancies at smallest film thicknesses show that the system is in an intermediate state between in-plane and out-of-plane domains, which is not described by existing analytical domain models

    Visibility in space - Target description subroutine

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    Computer subroutine for use in calculating visibility of Lunar Excursion Module /LEM/ ASCENT stage during moon orbit rendezvous with Command Service Module /CSM

    Assignment of grammatical functions in discourse context and word-order ambiguity resolution

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    In German, noun phrases (NPs) can be ambiguously case-marked as nominative (Subject) or accusative (Object). When readers encounter such ambiguous NPs in scrambled word orders they can experience processing difficulties (e.g., Hemforth, 1993; Knöferle, Crocker, Scheepers, & Pickering, 2001). However, what if preceding discourse context provides information for establishing the grammatical function of NPs? This information could influence readers’ interpretation of subsequent NPs. In principle, both the processing of sentences with scrambled and canonical word orders could profit from such contextual focus

    Design, fabrication and performance of an ellipsoidal spectroreflectometer

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    Far infrared ellipsoidal spectrophotometer design, fabrication, and performanc

    Deterministic enhancement of coherent photon generation from a nitrogen-vacancy center in ultrapure diamond

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    The nitrogen-vacancy (NV) center in diamond has an optically addressable, highly coherent spin. However, an NV center even in high quality single-crystalline material is a very poor source of single photons: extraction out of the high-index diamond is inefficient, the emission of coherent photons represents just a few per cent of the total emission, and the decay time is large. In principle, all three problems can be addressed with a resonant microcavity. In practice, it has proved difficult to implement this concept: photonic engineering hinges on nano-fabrication yet it is notoriously difficult to process diamond without degrading the NV centers. We present here a microcavity scheme which uses minimally processed diamond, thereby preserving the high quality of the starting material, and a tunable microcavity platform. We demonstrate a clear change in the lifetime for multiple individual NV centers on tuning both the cavity frequency and anti-node position, a Purcell effect. The overall Purcell factor FP=2.0F_{\rm P}=2.0 translates to a Purcell factor for the zero phonon line (ZPL) of FPZPL∼30F_{\rm P}^{\rm ZPL}\sim30 and an increase in the ZPL emission probability from ∼3%\sim 3 \% to ∼46%\sim 46 \%. By making a step-change in the NV's optical properties in a deterministic way, these results pave the way for much enhanced spin-photon and spin-spin entanglement rates.Comment: 6 pages, 4 figure
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