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Impact of Inaccuracy in fMRI Experimental Stimulation
Mikl, Michal ; Kremláček,, Jan (referee) ; Michálek, Jiří (referee) ; Drastich, Aleš (advisor)
Aim of this work is to study the impact of inaccuracy in execution of required task (inaccuracy in subject’s behavioral response to experimental stimulation) by person who undergoes fMRI examination. The work is solved in several stages. First, theoretical analysis of inaccuracy in fMRI experiment was performed, and simulations with synthetic data were created. Several variables in general linear model and t-statistics were followed. We found that estimated effect size depends linearly on covariance between the corresponding columns of X and D matrices or their linear combination. The component of residual variance caused by inaccuracy is negligible at real-life noise levels. In such case, moreover, the dependence of t-statistics on inaccuracy becomes linear. Next, our theoretical results (dependencies/characteristics of variables) were verified using real data. All results were confirmed. Last, I focused on possible practical use of the uncovered characteristics and dependencies. Optimization of experimental design with respect to inaccuracy, correction of inaccurate results and reliability of inaccurate results are introduced and discussed. Especially, the calculation of maps of maximal tolerable inaccuracy can be useful to find robust or weak (tending to be not detected or to be significantly different from accurate value) activation in real fMRI experiments.
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Control charts based on Bayes approach
Michálek, Jiří
An algorithm for detecting changes in the behaviour of a random variable based on the Bayes approach is suggested in the report and then is applied to construction of control charts for averages and standard deviation
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Statistical Process Control with SW Support
Michálek, Jiří ; Král, J.
The contribution deals with the analysis of situation in a manufacturing process by application of SPC methods.The approach is described by use of methodological schemes together with attention to problems that can occur by noncorrect usage of statistical tools. The contribution contains also an illustrative example of data analysis by application of a suitable software.
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