The response of a tree trunk to a hammer blow, measured by sensors positioned around the excited cross section, consists of two kinds of transient mechanical waves: longitudinal P- and transverse S-waves. The aim of this paper is to extract the velocity of the S-waves, using a filtering structure that emphasizes the waves heading in one of the directions along the circumference. By this approach,

This paper deals with noise suppression in multichannel measurements, using a certain signal model but without assuming stationarity of the signals involved. This enables application to signals whose spectral characteristics are time-variable. The novelty consists of an algorithm for obtaining an approximation of the Wiener filter for each channel. The filters are computed using the Weyl transform

Peak matched multiple windows are found as the Karhunen-Loeve basis functions of a predefined peaked spectrum. With a penalty function, an optimization procedure can be constrained with resulting control of sidelobes. Weighting factors, included in the averaging of the periodograms, can be designed to fulfill certain constraints. Desirable properties are low variance and small bias. This paper pre

The paper proposes a new multiple window method for estimating a peaked spectrum. The multiple windows are adapted to the signal, giving a less biased estimate for estimation of peaks than does the Thomson multiple window method. Still the result from estimation of a flat spectrum shows comparable results in variance reduction. The method is based on solution of an eigenvalue problem where the eig

The latency and amplitude of the midlatency auditive evoked potential's (AEP) Nb-trough has been found to indicate the depth of anaesthesis. The aim of this paper is to present a system that reliably estimates these parameters without a long time delay. The result shows that it is possible to estimate and track changes in latency and amplitude of the Nb-trough with a delay below 1 minute at a stim

Hur man beskriver och eftersträvar välbefinnande är viktigt, eftersom det påverkar både forskning och samhället i stort. Denna avhandling handlar om hur välbefinnande definieras och mäts, vilket både innefattar en kritisk diskussion kring befintliga teorier om välbefinnande samt en utveckling av empiriska metoder och statistiska verktyg för att öka vår förståelse gällande hur personer uppfattar ocHow to define and measure individuals’ well-being is important, as this has an impact on both research and society at large. This thesis concerns how to define and measure the self-reported well-being of individuals, which involves both theorizing as well as developing and applying empirical and statistical methods in order to gain a better understanding of well-being.The first paper critically re

The spectral characters of the electroencephalogram activity (EEG) is of interest both in studies of the EEG and in estimation oI Evoked Potentials. Often parametric methods assume an underlying model like AR or ARMA [1]. To avoid the model assumption a non-parametric multiple-window meihod for spectral estimation is used in this paper. The method uses Slepian's Discrete Prolate Spheroidal Wave Fu

An algorithm for estimation of event related signals dis-turbed by coloured noise, e.g. Evoked Potentials disturbed byEEG, has been investigated. The method is based on GeneralSingular Value Decomposition, GSVD, and estimates a singleEvoked Potential without averaging. There are no assumptionsabout the model for the EEG. The EP is described as a sum ofdamped sinusoids. The algorithm is tested with

A study is done concerning event related potentials in coloured noise, such as evoked potential signals (EP) in EEG. Two estimators, both based on the least square version of the Prony method, combined with singular value decomposition, have been investigated. The EP is described by a sum of damped sinusoids in both estimators. In the first estimator the noise is described by an ARMA—process and in

PurposeThe activities of academic researchers are increasingly regulated by neo-liberal ideals, including expectations that researchers are visible online and actively promote their output. The purpose of this paper is to explore how researchers take on this responsibility. It uses the concepts of genre, authorship and self-writing in order to understand how the story of an academic life is constr