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A resampling method for quantitative MRS is presented that retains absolute concentrations. Averaging the spectra from a subset improved the concentrationestimates via increased SNR. Using short-TE STEAM spectra from human thalamus, the influence of subset size was systematically studied and verifiedagainst conventional bootstrap re-sampling. Even small subsets provided considerably better signal-
Image quality is in essence based on subjective experience, and the involvement of human subjects is therefore necessary in one way or the other in order to make reliable assessments of it. This topic is of interest for Axis Communications AB -- the market leader in surveillance cameras. In this thesis, the softcopy quality ruler method described in ISO 20462 is evaluated through a study of one s
In a recent study, Bai (2013) proposes a new factor analytical (FA) method for estimation of stationary dynamic panel data models with fixed effects. Our interest in this method originates with the fact it does not require explicit demeaning of the data, a practice that is known to cause problems of bias and low power in near unit root panels. The purpose is to study the properties of FA when appl
Purpose: The purpose is to investigate which of the selected models that forecasts the out-of-sample data most accurate and whether the model based estimators make better forecasts than the implied volatility. Methodology: Trough in-sample data from a Swedish stock index return series and a exchange rate return series, different forecasting models are evaluated to see which one that predicts the
This thesis compares three different tests by analyzing the difference in sample means between two different data samples, both with small sample sizes. The three tests being examined here are the t-test, nonparametric bootstrap, and permutation test. These tests are employed under several different circumstances, such as varying sample sizes, means, underlying distributions, and variances in the
BACKGROUND: Lead time, the estimated time by which screening advances the date of diagnosis, is used to calculate the risk of overdiagnosis. We sought to describe empirically the distribution of lead times between an elevated prostate-specific antigen (PSA) and subsequent prostate cancer diagnosis. METHODS: We linked the Swedish cancer registry to two independent cohorts: 60-year-olds sampled in 1
Abstract Value at Risk (VaR) is a simple, transparent and consistent measure that summarizes all sources of downside risk. VaR has gained acceptance in the banking industry in accordance to Basel II rules which require banks to use VaR in calculations of market risk. VaR as a risk measure is not as widely accepted in the investment industry. This thesis embraces five different VaR models to 20 equ
The “Fundamental Review of the Trading Book” calculates the capital requirements using Expected Shortfall (ES) backtests since Value at risk (VaR) neglects losses in the tail. Additionally, real estate investments have increased significantly, which warrants an exploration of the asset class. This study applies eight different univariate GARCH models to six distinct property indices; Global, Asia
Context. The Gaia-ESO Survey (GES) is a large public spectroscopic survey at the European Southern Observatory Very Large Telescope. Aims. A key aim is to provide precise radial velocities (RVs) and projected equatorial velocities (v sin i) for representative samples of Galactic stars, which will complement information obtained by the Gaia astrometry satellite. Methods. We present an analysis to e
Genome-wide association studies (GWAS) for biomarkers important for clinical phenotypes can lead to clinically relevant discoveries. Conventional GWAS for quantitative traits are based on simplified regression models modeling the conditional mean of a phenotype as a linear function of genotype. We draw attention here to an alternative, lesser known approach, namely quantile regression that natural
Evaluating the effect of measurement errors on either adaptive or simultaneous control charts has been a topic of interest for the researchers in the recent years. Nevertheless, the effect of measurement errors on both adaptive and simultaneous monitoring control charts has not been considered yet. In this paper, through extensive numerical studies, we evaluate the effect of measurement errors on
When testing for unit roots using the Dickey-Fuller test, the presence of structural breaks can cause serious size distortions to the test. Previous research has suggested two modified tests, the weighted symmetric and the recursively mean-adjusted test, that has robust size properties even in the presence of a structural break. However, recent findings have shown that the power of the two modifie
Objective: No method has yet been established to summarise different objective indicators of social outcomes into one score. The study aimed to develop and test a simple, brief and meaningful index of social outcomes that can be used across a broad range of mental health studies and is potentially obtainable from routine documentation. Method: An index capturing employment, accommodation and livin
The outcomes of press perturbation experiments on community dynamics are difficult to predict because there is a high degree of indeterminacy in the strength and direction of ecological interactions. Ecologists need to quantify uncertainties in estimates of interaction strength, by determining all the possible values a given interaction strength could take and the relative likelihood of each value
Value at Risk is a commonly used risk measure which calculates the smallest losses you risk to lose from having an asset, given a certain risk level and time period. Even though Value at Risk is applicable to all different types of assets, some studies suggest that this risk measure is not suitable for developing countries/emerging markets. This is because these countries’ assets generate very obs
