497 research outputs found

    Advanced tracking and data relay experiments study: Multimode transponder experiment equipment

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    Plans and implementation concepts were developed for a series of experiments utilizing a Multimode Transponder mounted in an aircraft working either through a spacecraft or directly with a ground station which would simulate a TDRSS user working through the TDRSS. The purpose of the experiments is to determine the best modulation and encoding techniques for combating RFI in discreet bands. The experiments also determine the feasibility and accuracy of range and range rate measurements with the various modulation and encoding techniques. An analysis of the Multimode Transponder and ground support equipment is presented, and the additional equipment required to perform the experiments described above is determined

    Design study of a low cost civil aviation GPS receiver system

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    A low cost Navstar receiver system for civil aviation applications was defined. User objectives and constraints were established. Alternative navigation processing design trades were evaluated. Receiver hardware was synthesized by comparing technology projections with various candidate system designs. A control display unit design was recommended as the result of field test experience with Phase I GPS sets and a review of special human factors for general aviation users. Areas requiring technology development to ensure a low cost Navstar Set in the 1985 timeframe were identified

    Advanced tracking and data relay experiment study: Multimode transponder experiment

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    A series of experiments utilizing a multimode transponder mounted in an aircraft working either through a spacecraft or directly with a ground station is studied. The purpose of the experiments is to determine the best modulation and encoding techniques for combating RFI and multipath propagation and to determine the characteristics of VHF and UHF RFI in discreet bands. The experiments would also determine the feasibility and accuracy of range and range rate measurements with the various modulation and encoding techniques

    TDRSS multimode transponder program. Phase 2: Equipment development

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    This report contains a complete description of the TDRS Multimode Transponder and its associated ground support equipment. The transponder will demonstrate candidate modulation techniques to provide the required information for the design of an eventual VHF/UHF transponder suitable for installation in a user satellite, capable of operating as part of a Tracking and Data Relay Satellite (TDRS) systems. Use of geosynchronous TDRS which can serve both low data rate users at VHF and high data rate users at other frequencies has been considered. The effects of radio frequency interference from the earth and of multipath propagation due to reflections from the earth are expected to pose problems for the TDRS system at VHF. Investigations have suggested several modulation techniques that offer promise to overcome these problems

    TDRSS telecommunications study. Phase 1: Final report

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    A parametric analysis of the telecommunications support capability of the Tracking and Data Relay Satellite System (TDRSS) was performed. Emphasis was placed on maximizing support capability provided to the user while minimizing impact on the user spacecraft. This study evaluates the present TDRSS configuration as presented in the TDRSS Definition Phase Study Report, December 1973 to determine potential changes for improving the overall performance. In addition, it provides specifications of the user transponder equipment to be used in the TDRSS

    Qualitative development and content validation of the "SPART" model:a focused ethnography study of observable diagnostic and therapeutic activities in the emergency medical services care process

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    Abstract Background Clinical reasoning is a crucial task within the Emergency Medical Services (EMS) care process. Both contextual and cognitive factors make the task susceptible to errors. Understanding the EMS care process’ structure could help identify and address issues that interfere with clinical reasoning. The EMS care process is complex and only basically described. In this research, we aimed to define the different phases of the process and develop an overarching model that can help detect and correct potential error sources, improve clinical reasoning and optimize patient care. Methods We conducted a focused ethnography study utilizing non-participant video observations of real-life EMS deployments combined with thematic analysis of peer interviews. After an initial qualitative analysis of 7 video observations, we formulated a tentative conceptual model of the EMS care process. To test and refine this model, we carried out a qualitative, thematic analysis of 28 video-recorded cases. We validated the resulting model by evaluating its recognizability with a peer content analysis utilizing semi-structured interviews. Results Based on real-life observations, we were able to define and validate a model covering the distinct phases of an EMS deployment. We have introduced the acronym “SPART” to describe ten different phases: Start, Situation, Prologue, Presentation, Anamnesis, Assessment, Reasoning, Resolution, Treatment, and Transfer. Conclusions The “SPART” model describes the EMS care process and helps to understand it. We expect it to facilitate identifying and addressing factors that influence both the care process and the clinical reasoning task embedded in this process

    Themadag: Balans tussen fokkerij en biodiversiteit bij paarden

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    Aan kondiging van de themadag:"Balans tussen fokkerij en biodiversiteit bij paarden". Tijdens deze themadag worden basisprincipes van fokkerij en van behoud vangenetische diversiteit binnen een ras uitgelegd. Een goed doordacht fokbeleid op rasniveau is nodig om het ras te behouden of te verbeteren. Daarbij moet ook worden gelet op behoud van genetische diversiteit binnen het ras. Een te sterke inteelttoename kan tot serieuze problemen leiden, zoals bepaalde erfelijke gebreken. Een kleine populatie is kwetsbaarder voor inteelt dan een grote populatie. Tevens geeft een sterke selectie op één of enkele kenmerken een groter risico op inteel

    Machine learning in anesthesiology:Detecting adverse events in clinical practice

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    The credibility of threshold-based alarms in anesthesia monitors is low and most of the warnings they produce are not informative. This study aims to show that Machine Learning techniques have a potential to generate meaningful alarms during general anesthesia without putting constraints on the type of procedure. Two distinct approaches were tested - Complication Detection and Anomaly Detection. The former is a generic supervised learning problem and for this a simple feed-forward Neural Network performed best. For the latter, we used an Encoder-Decoder Long Short-Term Memory architecture that does not require a large manually-labeled dataset. We show this approach to be more flexible and in the spirit of Explainable Artificial Intelligence, offering greater potential for future improvement
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