Sökning: "uncertainty intervals"

Visar resultat 1 - 5 av 33 avhandlingar innehållade orden uncertainty intervals.

1. 1. Environmental Modelling : Learning from Uncertainty

   Författare :John M. Juston; Per-Erik Jansson; Jens Christian Refsgaard; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Models; data; error; uncertainty; hydrology; soil carbon; wetlands; phosphorus;

   Sammanfattning : Environmental models are important tools; however uncertainty is pervasive in the modeling process.   Current research has shown that under­standing and representing these uncertainties is critical when decisions are expected to be made from the modeling results. LÄS MER

3. 2. Uncertainty intervals and sensitivity analysis for missing data

   Författare :Minna Genbäck; Xavier de Luna; Elena Stanghellini; Arvid Sjölander; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; missing data; missing not at random; non-ignorable; set identification; uncertainty intervals; sensitivity analysis; self reported health; average causal effect; average causal effect on the treated; mixed-effects models; Statistics; statistik;

   Sammanfattning : In this thesis we develop methods for dealing with missing data in a univariate response variable when estimating regression parameters. Missing outcome data is a problem in a number of applications, one of which is follow-up studies. LÄS MER

4. 3. Uncertainty, variability and environmental risk analysis

   Författare :Monika Filipsson; Tomas Öberg; Bo Bergbäck; Lars Rosén; Linnéuniversitetet; []
   Nyckelord :Contaminated land; exposure assessment; exposure factors; risk analysis; risk perception; uncertainty; variability; probabilistic risk assessment; NATURAL SCIENCES; NATURVETENSKAP; Miljövetenskap; Environmental Science;

   Sammanfattning : The negative effects of hazardous substances and possible measures that can be taken are evaluated in the environmental risk analysis process, consisting of risk assessment, risk communication and risk management. Uncertainty due to lack of knowledge and natural variability are always present in this process. LÄS MER

5. 4. Critical loads - assessment of uncertainty

   Författare :Andreas Barkman; Avdelningen för kemiteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; landscape planning; regionalisation; forestry; BC Al; sensitivity analysis; risk assessment; Monte Carlo simulation; PROFILE; critical level; exceedance; Acidification; forest soil; policy; EMEP; GIS.; Chemical technology and engineering; Kemiteknik och kemisk teknologi;

   Sammanfattning : The effects of data uncertainty in applications of the critical loads concept were investigated on different spatial resolutions in Sweden and northern Czech Republic. Critical loads of acidity (CL) were calculated for Sweden using the biogeochemical model PROFILE. LÄS MER

7. 5. Methods for longitudinal brain imaging studies with dropout

   Författare :Tetiana Gorbach; Xavier de Luna; Anders Lundquist; Martin A. Lindquist; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Missing data; nonignorable dropout; sensitivity analysis; uncertainty intervals; pattern-mixture models; aging; cognition; MRI; brain structure; resting-state functional connectivity; Statistics; statistik;

   Sammanfattning : One of the challenges in aging research is to understand the brain mechanisms that underlie cognitive development in older adults. Such aging processes are investigated in longitudinal studies, where the within-individual changes over time are observed. However, several methodological issues exist in longitudinal analyses. LÄS MER