Sökning: "missing samples"

Visar resultat 1 - 5 av 66 avhandlingar innehållade orden missing samples.

  1. 1. Two Topics in Survey Methodology : Inference from Nonprobability Samples Using the Double Samples Setup

    Författare :Boris Lorenc; Daniel Thorburn; Lars Lyberg; Gösta Forsman; Stockholms universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; response process; establishment surveys; socially distributed cognition; response burden; measurement error; nonprobability samples; web surveys; double samples; propensity scores; model-based estimation; imputation; nonparametric imputation; weighting; Surveying; Lantmäteri;

    Sammanfattning : Modelling the response process in establishment surveys proceeded thus far by adding steps of operational character to the core cognitive steps of the individual cognitive model. Here (Paper 1) a larger unit of the cognitive analysis is posited: that part of the enterprise that is engaged in responding to a survey, consisting of one or more employees, the tools they use and the established practices of record keeping and survey responding. LÄS MER

  3. 2. Design and analysis of response selective samples in observational studies

    Författare :Maria Grünewald; Ola Hössjer; Keith Humphreys; Marie Reilly; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; ascertainment; missing data; outcome dependent sampling; response selective samples; sequential design; stochastic EM algorithm; Mathematical statistics; Matematisk statistik; Mathematical Statistics; matematisk statistik;

    Sammanfattning : Outcome dependent sampling may increase efficiency in observational studies. It is however not always obvious how to sample efficiently, and how to analyze the resulting data without introducing bias. LÄS MER

  4. 3. Particle induced x-ray emission - analysis of biological samples

    Författare :Jan Pallon; Kärnfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Fysicumarkivet A:1987:Pallon;

    Sammanfattning : [abstract missing].... LÄS MER

  5. 4. Precise Image-Based Measurements through Irregular Sampling

    Författare :Teo Asplund; Robin Strand; Cris L. Luengo Hendriks; Matthew J. Thurley; Gunilla Borgefors; Hugues Talbot; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; image analysis; image processing; mathematical morphology; irregular sampling; adaptive morphology; missing samples; continuous morphology; path opening.; Computerized Image Processing; Datoriserad bildbehandling;

    Sammanfattning : Mathematical morphology is a theory that is applicable broadly in signal processing, but in this thesis we focus mainly on image data. Fundamental concepts of morphology include the structuring element and the four operators: dilation, erosion, closing, and opening. LÄS MER

  7. 5. Fluorine mass balance in wildlife and consumer products : How much organofluorine are we missing?

    Författare :Lara Schultes; Jonathan P. Benskin; Michael McLachlan; Jörg Feldmann; Elsie M. Sunderland; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; PFASs; PFOS; fluorine mass balance; organofluorine; EOF; TF; wildlife; consumer products; combustion ion chromatography; high resolution mass spectrometry; suspect screening; Applied Environmental Science; tillämpad miljövetenskap;

    Sammanfattning : Per- and polyfluoroalkyl substances (PFASs) are a class of anthropogenic pollutants. Many PFASs are highly persistent and have been linked to adverse effects in humans. According to latest estimates, there are more than 4700 PFASs in global commerce, which poses immense challenges for environmental monitoring. LÄS MER