Sökning: "missing samples"

Visar resultat 1 - 5 av 49 avhandlingar innehållade orden missing samples.

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

    Detta är en avhandling från Stockholm : Statistiska institutionen

    Författare :Boris Lorenc; Stockholms universitet.; [2006]
    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; TECHNOLOGY Civil engineering and architecture Surveying; TEKNIKVETENSKAP Samhällsbyggnadsteknik och arkitektur 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

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

    Detta är en avhandling från Stockholm : Department of Mathematics, Stockholm University

    Författare :Maria Grünewald; Stockholms universitet.; [2011]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; ascertainment; missing data; outcome dependent sampling; response selective samples; sequential design; stochastic EM algorithm; MATHEMATICS Applied mathematics Mathematical statistics; MATEMATIK Tillämpad matematik Matematisk statistik; matematisk statistik; Mathematical Statistics;

    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

  3. 3. Precise Image-Based Measurements through Irregular Sampling

    Detta är en avhandling från Uppsala : Acta Universitatis Upsaliensis

    Författare :Teo Asplund; Uppsala universitet.; Uppsala universitet.; [2019]
    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

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

    Detta är en avhandling från Stockholm : Department of Environmental Science and Analytical Chemistry, Stockholm University

    Författare :Lara Schultes; Jonathan P. Benskin; Michael McLachlan; Jörg Feldmann; Elsie M. Sunderland; [2019]
    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

  5. 5. Truncation and missing family links in population-based Registers

    Detta är en avhandling från Stockholm : Karolinska Institutet, Department of Medical Epidemiology and Biostatistics

    Författare :Monica Leu; Karolinska Institutet.; Karolinska Institutet.; [2008]
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Left-trunction; Swedish Cancer Registry; MultiGeneration Register; family history; misclassification; simulation; Poplab;

    Sammanfattning : Studies of familial aggregation of disease routinely use linked population registers to construct retrospective cohorts. Although such resources have provided numerous estimates of familial risk, little is known regarding the sensitivity of the estimates to assumed disease models and incompleteness of the data, such as truncation and/or missing family links. LÄS MER