654 research outputs found

    Canister for Producing TMA Trails in the Upper Atmosphere

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    Payload canister for producing trimethyl aluminum trails in upper atmosphere using Nike-Cajun or Nike-Apache rocke

    A study to guide research and development toward an operational meteorological sounding rocket system Final report, Oct. 1966 - Apr. 1967

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    Research and development guide for operational meteorological sounding rocket system stressing vehicle

    Measurement of upper atmospheric ionization and winds with a combined payload first quarterly report, 24 jul. - 31 oct. 1964

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    Nike-Apache rocket payloads for upper atmosphere ionization measurement and wind determinatio

    Tracking Dengue Epidemics using Twitter Content Classification and Topic Modelling

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    Detecting and preventing outbreaks of mosquito-borne diseases such as Dengue and Zika in Brasil and other tropical regions has long been a priority for governments in affected areas. Streaming social media content, such as Twitter, is increasingly being used for health vigilance applications such as flu detection. However, previous work has not addressed the complexity of drastic seasonal changes on Twitter content across multiple epidemic outbreaks. In order to address this gap, this paper contrasts two complementary approaches to detecting Twitter content that is relevant for Dengue outbreak detection, namely supervised classification and unsupervised clustering using topic modelling. Each approach has benefits and shortcomings. Our classifier achieves a prediction accuracy of about 80\% based on a small training set of about 1,000 instances, but the need for manual annotation makes it hard to track seasonal changes in the nature of the epidemics, such as the emergence of new types of virus in certain geographical locations. In contrast, LDA-based topic modelling scales well, generating cohesive and well-separated clusters from larger samples. While clusters can be easily re-generated following changes in epidemics, however, this approach makes it hard to clearly segregate relevant tweets into well-defined clusters.Comment: Procs. SoWeMine - co-located with ICWE 2016. 2016, Lugano, Switzerlan

    Observations of chemical releases from high flying aircraft

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    Barium and lithium vapors were released from sounding rockets in the thermosphere and observed from aboard the NASA Convair 990 at an altitude of 40,000 ft. The purpose of the releases was to (1) check out observational and operational procedures associated with the large high altitude barium release from a Scout rocket (BIC); (2) develop an all-weather technique for observing chemical releases; (3) evaluate methods of observing daytime releases, and (4) investigate the possibilities of observations from a manned satellite. The initial analysis indicates that the previous limitations on the usage of the vapor release method have been removed by the use of the aircraft and innovative photographic techniques. Methods of analysis and applications to the investigation of the thermosphere are discussed

    Caddo Archives and Economies

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    This article is a discussion of archival research on contact through historic period (ca. A.D. 1519 to 18th century) Caddo groups in eastern Texas and west central Louisiana. First, I describe general objectives for current and long-term research on the Caddo Indians, followed by the central issues the article will address. A brief summary of protohistoric and historic events, actors, and sources will be followed by methodological considerations, as well as a discussion of Caddo economies, concluding with some reflections on Caddo archives and economies. This article explores the complex and interrelated economies of Native American and European populations during the colonization process in early Spanish Texas

    Identification of aircrew tasks for using direct voice input (DVI) to reduce pilot workload in the AH-64D Apache Longbow

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    Advances in helicopter design continue to saturate the pilot\u27s visual channel and produce remarkable increases in cognitive workload for the pilot. This study investigates the potential implementation of Direct Voice Input (DVI) as an alternative control for interacting with onboard systems of the AH-64D Apache, in an attempt to reduce pilot workload during a hands on the controls and eyes out condition. The intent is to identify AH-64D cockpit tasks performed through Multi Purpose Displays (MPDs) that when converted to DVI will provide the greatest reduction in task execution time and workload. A brief description of applicable AH-64D audio and visual displays are provided. A review of current trends in state-of-the-art voice recognition technology is presented, as well as previous and current voice input cockpit identification studies. To identify tasks in the AH-64D, a methodology was developed consisting of a detailed analysis of the aircraft\u27s mission and on-board systems. A pilot questionnaire was developed and administered to operational AH-64D pilots to assess their input on DVI implementation. Findings indicate DVI would be most useful for displaying selected MPD pages and performing tasks pertaining to the Tactical Situation Display (TSD), weapons, and communications. Six of the candidate DVI tasks were performed in the AH-64D simulator using the manual input method and a simulated voice input method. Two different pilots made objective and subjective evaluations. Task execution times and workload rating were lower using a simulated means of voice input. Overall, DVI shows limited potential for workload reduction and warrants further simulator testing before proceeding to the flight environment
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