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Describes a method to measure changes in the mid-latency auditory evoked potential (MLAEP) during anesthesia. It is claimed that the position of the Nb-trough of the MLAEP indicates the level of consciousness. The component shows graded changes corresponding to the dose of anesthetic and it exhibits stable reproducible properties between different subjects. The authors propose a system that reduce
A multiple window method for estimation of the peaked power density spectrum is designed. The method optimizes a filter function utilizing the Karhunen-Loeve basis functions of a known peaked spectrum as windows to reduce variance and bias in the locality of the frequency peak. For improving performance, a penalty function is used to suppress the sidelobes outside a given bandwidth. The improved w
We address the problem of detecting double-talk in a full duplex transmission line. A new double-talk detector (DTD) based on measuring the similarity between the far- and near-end speech signals is proposed. The detector is block oriented and operates in the frequency domain where the similarity between the signals is measured by means of the coherence function. The coherence is estimated with a
This paper deals with estimation of the waveform of a single event-related potential, sERP. An additive noise model is used for the measured signal and the SNR of the disturbed sERP is approximately 0 dB. The sERP is described by a series expansion where the basis functions are damped sinusoids. The fundamental basis function is estimated by the least squares Prony method, derived for colored nois
Rot in living trees cause substantial losses for the forestry industry. The common practice when evaluating forest stands for, e.g., purchase, is assessment based on visual signs. In this paper a new non-destructive assessment method based on the impact excitation method is proposed. The trunk of a living tree is excited by the impact of a hammer, and the vibrations are measured by accelerometers.
The glycosylated multivalent three-domain Kunitz inhibitor TFPI is a natural inhibitor of tissue factor-FVIIa complex in the presence of FXa. TFPI has an experimental antithrombotic capacity indistinguishable from LMWH in a prophylactic dose, regardless of glycosylation and of the third domain. An inherited equilibrium between antithrombosis and haemorrhage exists. The aim of the study was to eval
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
