756 research outputs found

    Launch Commit Criteria Monitoring Agent

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    The Spaceport Processing Systems Branch at NASA Kennedy Space Center has developed and deployed a software agent to monitor the Space Shuttle's ground processing telemetry stream. The application, the Launch Commit Criteria Monitoring Agent, increases situational awareness for system and hardware engineers during Shuttle launch countdown. The agent provides autonomous monitoring of the telemetry stream, automatically alerts system engineers when predefined criteria have been met, identifies limit warnings and violations of launch commit criteria, aids Shuttle engineers through troubleshooting procedures, and provides additional insight to verify appropriate troubleshooting of problems by contractors. The agent has successfully detected launch commit criteria warnings and violations on a simulated playback data stream. Efficiency and safety are improved through increased automation

    Statistical study of conductance properties in one-dimensional quantum wires focusing on the 0.7 anomaly

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    The properties of conductance in one-dimensional (1D) quantum wires are statistically investigated using an array of 256 lithographically-identical split gates, fabricated on a GaAs/AlGaAs heterostructure. All the split gates are measured during a single cooldown under the same conditions. Electron many-body effects give rise to an anomalous feature in the conductance of a one-dimensional quantum wire, known as the `0.7 structure' (or `0.7 anomaly'). To handle the large data set, a method of automatically estimating the conductance value of the 0.7 structure is developed. Large differences are observed in the strength and value of the 0.7 structure [from 0.630.63 to 0.84×(2e2/h)0.84\times (2e^2/h)], despite the constant temperature and identical device design. Variations in the 1D potential profile are quantified by estimating the curvature of the barrier in the direction of electron transport, following a saddle-point model. The 0.7 structure appears to be highly sensitive to the specific confining potential within individual devices.This is the author's accepted manuscript. The final version is published by ACS in Physical Review B and can be found here: http://journals.aps.org/prb/abstract/10.1103/PhysRevB.90.045426

    Assisted extraction of the energy level spacings and lever arms in direct current bias measurements of one-dimensional quantum wires, using an image recognition routine

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    A multiplexer technique is used to individually measure an array of 256 split gates on a single GaAs/AlGaAs heterostructure. This results in the generation of large volumes of data, which requires the development of automated data analysis routines. An algorithm is developed to find the spacing between discrete energy levels, which form due to transverse confinement from the split gate. The lever arm, which relates split gate voltage to energy, is also found from the measured data. This reduces the time spent on the analysis. Comparison with estimates obtained visually show that the algorithm returns reliable results for subband spacing of split gates measured at 1:4 K. The routine is also used to assess DC bias spectroscopy measurements at lower temperatures (50 mK). This technique is versatile and can be extended to other types of measurements. For example, it is used to extract the magnetic field at which Zeeman-split 1D subbands cross one another.This work was supported by the Engineering and Physical Sciences Research Council grant No. EP/IO14268/1.This is the accepted manuscript. The final version is available from AIP at http://scitation.aip.org/content/aip/journal/jap/117/1/10.1063/1.4905484

    Writing in Britain and Ireland, c. 400 to c. 800

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    Implementation of virtual OSCE in Health Professions Education: a Systematic Review

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    Introduction: The Objective Structured Clinical Examination (OSCE) has been widely used in health professions education since the 1970s. The global disruption caused by the COVID-19 pandemic restricted in-person assessments and medical educators globally sought alternative means to assess and certify students and trainees to meet the acute demand for health-care workers. One such solution was through virtual OSCE (vOSCE), which modified traditional in-person OSCE using videoconference platforms. This meta-ethnography sought to synthesise qualitative literature on candidates' and assessors' experiences of vOSCE to evaluate whether it may have a role in future assessment practices. Methods: In June 2022, we systematically searched PsycINFO, Medline and ERIC for peer-reviewed qualitative and mixed-methods articles that described candidates' and assessors' experiences of virtual OSCE in health professions education. Of 1069 articles identified, 17 were synthesised using meta-ethnography. Results: The final synthesis represented 1190 candidates and assessors from faculties of medicine, dentistry, nursing, pharmacy and osteopathy. We developed our findings into four key concepts. ‘Strengthening confidence in a virtual environment’ highlighted attempts to overcome and mitigate concerns associated with transitioning from in-person to virtual assessment. ‘Understanding the scope of use as an assessment’ reflected on the suitability of vOSCE in assessing various skills. ‘Refining operational processes’ emphasised the technical challenges of implementing vOSCE and impacts on accessibility and resources. ‘Envisioning its future role’ considered the applicability of vOSCE in the climate of rapid development in telehealth. Conclusion: This meta-ethnography highlighted that although vOSCE was primarily considered a temporary and crisis response, candidates and assessors recognised positive, as well as negative, consequences of the transition towards them. Moving forward, medical education policymakers should carefully consider the extent to which elements of vOSCE could be incorporated into assessment systems, particularly in light of the rise of telehealth in clinical practice
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