291,724 research outputs found

    Sensor Characterization and Signal Fusion for InstantEye

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    The practicality and effectiveness of using a TerraRanger Duo—a parallel sonar and infrared time-of-flight distance sensor—payload for obstacle detection is investigated for use with Physical Science Inc.’s InstantEye drone. A Python program was developed to interface with the serial data output before comparing the sensor’s empirical performance against its data sheet. The two signals from the distinct sensor modules, each with their characterized strengths and weaknesses, were then fused with a Kalman filter. This was further refined by imposing conditional weighting based on the known sensor characteristics. The filter output, with conditional corrections, was able to accurately track a single object’s position and velocity within a maximum range of 14 meters

    'Picturesque and dramatic' or 'dull recitals of threadbare fare': good practice in history teaching in elementary schools in England, 1872-1905

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    This article draws on late nineteenth- and early twentieth-century teaching manuals, reports of Her Majesty's Inspectors, history textbooks ('readers'), other administrators' and teachers' accounts, policy documents and pupils' reminiscences to refute common and generalised assessments of the period (often by those who have not looked closely at these specific sources) that the teaching of history was a negative and boring experience, limited mainly and simply to reading comprehension of lengthy pages devoid of timelines and visual materials. The article concentrates on the experience of English elementary schools and draws comparisons between past and present teaching approaches. The findings show that there is extant evidence that there did exist in the late Victorian period clear conceptions of how to make history accessible to children, many of which reflect current best practice in the subject. They also show that many leading educationalists, and probably the teachers who read them, were aware of the need to make the subject accessible to children. The pupils themselves have left very little evidence of their experience, but some pupils were enabled to develop picturesque understandings of the past of benefit to their lives beyond the classroom. © 2014 © 2014 Taylor & Francis

    The inauguration

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    From a special issue: A Brief History of the Charles Darwin Foundation for the Galapagos Islands 1959-198

    Study of changes in properties of solar sail materials from radiation exposure

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    Techniques for monitoring changes in preparation of solar sail materials resulting from space radiation simulation, stressing (e.g., thermal, mechanical) and exposure to terrestrial environments are developed. The properties of interest are: metallic coating deterioration, polymeric film deterioration, interfacial debonding and possible metallic coating diffusion into the polymeric film. Four accelerated tests were devised to simulate the possible degradation processes mentioned above. These four tests are: a thermal shock test to simulate the wide variation of temperature expected in space (260 C to -100 C), a cyclic temperature test to stimulate the 6 minute temperature cycle anticipated in space, a mechanical vibration test to simulate mechanical bonding, folding and handling, and a humidity test to simulate terrestrial environment effects. The techniques for monitoring property changes are: visual and microscopic examination, ellipsometry, surface potential difference (SPD), photoelectron emission (PEE), and water contact angles

    Three new species of Paragnorimus Becker from Central America (Coleoptera: Scarabaeidae: Cetoniinae: Trichiini) with a redefinition of the genus

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    Three new species of Paragnorimus Becker are described: Paragnorimus atratus n. sp. from Guatemala, P. hondurensis n. sp. from Honduras and Nicaragua, and P. howdeni n. sp. from Guatemala. Based on the overlapping characters of these new species, the genus Peltotrichius Howden is placed in synonymy with Paragnorimus. Paragnorimus is given a broader definition to encompass the new species and the two species formerly placed in the genus Peltotrichius

    The management of the National Park

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    From a special issue: A Brief History of the Charles Darwin Foundation for the Galapagos Islands 1959-198
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