Search for dissertations about: "sampling weights"

Showing result 1 - 5 of 24 swedish dissertations containing the words sampling weights.

  2. 1. Statistical modeling in international large-scale assessments

    Author : Inga Laukaityte; Marie Wiberg; Kenny Bränberg; Ewa Rolfsman; Bernard Veldkamp; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; multilevel model; plausible values; sampling weights; missing information; multiple imputation; non-monotone missing pattern; TIMSS; PISA; Statistics; statistik; pedagogik; Education;

    Abstract : This thesis contributes to the area of research based on large-scale educational assessments, focusing on the application of multilevel models. The role of sampling weights, plausible values (response variable imputed multiple times) and imputation methods are demonstrated by simulations and applications to TIMSS (Trends in International Mathematics and Science Study) and PISA (Programme for International Student Assessment) data. READ MORE

  4. 2. Cryptanalysis of Selected Stream Ciphers

    Author : Paul Stankovski; Institutionen för elektro- och informationsteknik; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Stream cipher; cryptanalysis; FCSR; state recovery; linear relations; optimal sampling; distinguisher; HC; nonrandomness; greedy bit set algorithm.;

    Abstract : The aim of this dissertation is to show some cryptanalytical results on a selection of stream ciphers. We have grouped theory and results into three main parts. The first part focuses on the FCSR-based constructions X-FCSR and F-FCSR-H v3. For the X-FCSR family of stream ciphers we perform a severe state recovery attack. READ MORE

  5. 3. Calibration Adjustment for Nonresponse in Sample Surveys

    Author : Bernardo João Rota; Thomas Laitila; Sune Karlsson; Risto Lehtonen; Örebro universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Auxiliary variables; Calibration; Nonresponse; principal com-ponents; regression estimator; response probability; survey sampling; two-step estimator; variance estimator; weighting; Statistics; Statistik;

    Abstract : In this thesis, we discuss calibration estimation in the presence of nonresponse with a focus on the linear calibration estimator and the propensity calibration estimator, along with the use of different levels of auxiliary information, that is, sample and population levels. This is a fourpapers- based thesis, two of which discuss estimation in two steps. READ MORE

  6. 4. Sampling and analysis of polynuclear aromatic hydrocarbons with special reference to automobile exhausts

    Author : Ulf Stenberg; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : A literature survey concerning the progress in sampling of polynu clear aromatic hydrocarbons, PAH, from automobile exhausts is pre seated. In this conjunction the included analytical methods are discussed, and some emphasis is put on injection technique and column performance. READ MORE

  7. 5. Towards Dense Air Quality Monitoring : Time-Dependent Statistical Gas Distribution Modelling and Sensor Planning

    Author : Sahar Asadi; Achim Lilienthal; Amy Loutfi; Dominque Martinez; Örebro universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; mobile robot olfaction; time-dependent gas distribution modelling; temporal sub-sampling; sensor planning; artificial potential field; gas monitoring;

    Abstract : This thesis addresses the problem of gas distribution modelling for gas monitoring and gas detection. The presented research is particularly focused on the methods that are suitable for uncontrolled environments. READ MORE