[abstract] PARAMETER ESTIMATION OF THE COPERNICUS BUBBLE MODEL USING HUMAN DOPPLER DATA

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[abstract] PARAMETER ESTIMATION OF THE COPERNICUS BUBBLE MODEL USING HUMAN DOPPLER DATA

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Title: [abstract] PARAMETER ESTIMATION OF THE COPERNICUS BUBBLE MODEL USING HUMAN DOPPLER DATA
Author: Gutvik, CR; Brubakk, AO
Abstract: BACKGROUND: The Copernicus project was started to establish a methodology for creating decompression procedures based on bubble dynamics and using bubble-measurements as validation rather than a binary outcome of DCS. The relationship between DCS risk and vascular bubbles has been previously shown (Nishi et al. 2003). The goal of the presented study was to make use of available Doppler data to estimate the parameters in the Copernicus bubble modeMATERIALS AND METHODS: Doppler scores from 185 bounce man dives were plotted in three dimensions to achieve a visual evaluation of how the relationship between depth/bottomtime and bubble formation can be described by a smooth mathematical function. The selected function is a sum of time/msw products in the range from 1st to 3rd power. The parameter estimation was formulated to minimize the sum of all errors between the smooth function and the bubble scores, being constrained to positive coefficients. The error terms were given customized punishment to avoid underestimation of the evolved gas phasRESULTS: The selected function had sufficient degrees of freedom to achieve an adequate fitness of the dataset. Still being simple enough to show an intuitive relationship between depth, bottomtime and bubble score on bounce dives. The function can be used to estimate bubble data for a large range of depths and bottomtimes which is necessary to estimate the parameters in the dynamic bubble modeCONCLUSIONS: Although bubble scores can be an additional tool for evaluating the stress/risk of a dive, it is a common problem that the variance of the measurements is relatively high. In general more stressful dives give higher bubble scores but still the majority of the dives produce no bubbles. If the goal is to keep a diver within an accepted risk, a regular least square method would underestimate the amount of generated gas volume
Description: Undersea and Hyperbaric Medical Society, Inc. (http://www.uhms.org )
URI: http://archive.rubicon-foundation.org/3621
Date: 2006

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  • UHMS Meeting Abstracts
    This is a collection of the published abstracts from the Undersea and Hyperbaric Medical Society (UHMS) annual meetings.

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