Showing 91 - 100 of 253
The purpose of the package fmri is the analysis of single subject functional magnetic resonance imaging (fMRI) data. It provides fMRI analysis from time series modeling by a linear model to signal detection and publication quality images. Specifically, it implements structural adaptive smoothing...
Persistent link: https://www.econbiz.de/10010986712
Diffusion weighted imaging (DWI) is a magnetic resonance (MR) based method to investigate water diffusion in tissue like the human brain. Inference focuses on integral properties of the tissue microstructure. The acquired data are usually modeled using the diffusion tensor model, a...
Persistent link: https://www.econbiz.de/10010986715
The results of analyzing experimental data using a parametric model may heavily depend on the chosen model. In this paper we propose procedures for the adequate selection of nonlinear regression models if the intended use of the model is among the following: prediction of future values of the...
Persistent link: https://www.econbiz.de/10005008409
A new approach to discriminant analysis based on projection pursuit density estimation is proposed. Projections are chosen to minimize estimates of the expected overall loss in each projection pursuit stage. Different strategies in the procedure concerning the choice of univariate density...
Persistent link: https://www.econbiz.de/10005065274
Digital imaging has become omnipresent in the past years with a bulk of applications ranging from medical imaging to photography. When pushing the limits of resolution and sensitivity noise has ever been a major issue. However, commonly used non-adaptive filters can do noise reduction at the...
Persistent link: https://www.econbiz.de/10005101520
In the semiparametric additive hazard regression model of McKeague and Sasieni (1994), the hazard contributions of some covariates are allowed to change over time, without parametric restrictions (Aalen model), while the contributions of other covariates are assumed to be constant. In this...
Persistent link: https://www.econbiz.de/10010983847
Diffusion weighted imaging has become and will certainly continue to be an important tool in medical research and diagnostics. Data obtained with diffusion weighted imaging are characterized by a high noise level. Thus, estimation of quantities like anisotropy indices or the main diffusion...
Persistent link: https://www.econbiz.de/10008460786
A simple non-stationary paradigm for the dynamics of multivariate returns is discussed. Unlike most of the multivariate econometric models for financial returns, our approach supposes the volatility to be exogenous and non-stationary. The vectors of returns are assumed to be animated by a slowly...
Persistent link: https://www.econbiz.de/10012731952
We propose an unconditional non-parametric approach to the simultaneous estimation of volatility and expected return. By means of a detailed analysis of the returns of the Standard amp; Poors 500 (Samp;P 500) composite stock index over the last fifty years we show how theoretical results and...
Persistent link: https://www.econbiz.de/10012734405
This paper investigates the relevance of the stationary, conditional, parametric ARCH modeling paradigm as embodied by the GARCH(1,1) process to describing and forecasting the dynamics of returns of the Standard amp; Poors 500 (Samp;P 500) stock market index.A detailed analysis of the series of...
Persistent link: https://www.econbiz.de/10012737125