Vibrationer i underlaget kan försämra prestandan hos kommunikationsantenner. Detta har undersökts i denna rapport.  Tre sändarantenner med olika utseende och egenskaper genomgick flera vibrationstester för att identifiera resonansfrekvenser i strukturen. Signalstyrkan mellan sändar- och mottagarantenn registrerades under alla tester för att identifiera resonansfrekvenser.  Vid försöken monterades antennerna på en sändarbox. När kretskortet i sändarboxen inte fixerades ordentligt orsakade det komplexa vibrationer i hela antennstrukturen. Detta kan vara en fråga som kräver separat omfattande forskning. I denna rapport studerades själva antennernas beteende och därför behövde sändarboxen gjutas för att garantera kretskortets fasta position. De tre antennerna visade alla olika beteende under testerna

This thesis pertains to the uses of functional data analysis and nonlinear mixed-effects model with applications to PET data. In the first part of this dissertation, we consider a permutation-based inference for function-on-scalar regression. While PET imaging data analysis is most commonly performed on data that are aggregated into several discrete a priori regions of interest, our primary interest is on measures of 5-HTT binding potential that are made at many locations along a continuous anatomically defined tract, one that was chosen to follow serotonergic axons. Our goal is to characterize the binding patterns along this tract, determine how such patterns differ between diagnostic groups, and also to investigate the question of homogeneity. We utilize function-on-scalar regression modeling to make optimal use of our data and inference is made using permutation testing strategies that do not require distributional assumptions. Simulations are conducted to examine the validity of our methods and compare the performance of competing methods. We illustrate this approach by applying it to PET data. In the second part of this dissertation, we introduce shape-based distance metrics for comparison of IRFs. The common practice involves summarizing the estimated IRF using a single scalar measure, such as VT, and comparing it across subjects/groups using standard univariate analyses. However, this approach neglects the nature and structure of the IRFs and overlooks their shapes. We propose a k-nearest-neighbor ensemble approach that optimally combines distance metrics based on principles of functional data analysis and shape data analysis. Simulations are conducted to compare the predictive performance of our approach to the traditional approach of using VT. We illustrate this approach by applying it to PET data. In the third part of this dissertation, we discuss the a nonlinear mixed-effects modeling approach for PET data analysis under the assumption of a simplified reference tissue model. The conventional two-stage approach uses NLS estimates of the population parameters, although statistically valid, it is possible to allow for more complex models that consider all subjects simultaneously. We propose a nonlinear mixed-effects (NLME) model that can estimate not only the individual-level parameters, but also the effects of covariates on the parameters. In this way, estimation of kinetic parameters and statistical inference can be performed simultaneously. Simulations are conducted to compare the power for detection of group differences and population- and individual-level parameter estimation for both NLS and NLME models. We apply our NLME approach to PET data to illustrate the modeling procedure.

This paper presents an exploratory study of aircraft engine fault indicators obtained from sound and vibration recordings. Observing time sequence and frequency spectra of the recordings, a simple yet cost-effective method of detecting engine fault is achieved. A detailed discussion of the study performed, ranging from the hardware and software selection, initial tests, and discoveries made in the time domain and subsequently in the frequency domain will be presented.

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Vibrationer i underlaget kan försämra prestandan hos kommunikationsantenner. Detta har undersökts i denna rapport.  Tre sändarantenner med olika utseende och egenskaper genomgick flera vibrationstester för att identifiera resonansfrekvenser i strukturen. Signalstyrkan mellan sändar- och mottagarantenn registrerades under alla tester för att identifiera resonansfrekvenser.  Vid försöken monterades antennerna på en sändarbox. När kretskortet i sändarboxen inte fixerades ordentligt orsakade det komplexa vibrationer i hela antennstrukturen. Detta kan vara en fråga som kräver separat omfattande forskning. I denna rapport studerades själva antennernas beteende och därför behövde sändarboxen gjutas för att garantera kretskortets fasta position. De tre antennerna visade alla olika beteende under testerna. Inga slutsatser om antennernas strukturella beteende kunde dras eftersom det var för få tester på för få antenner.

<p> Although most muscle spindle investigations have used the cat model and mvasiVe surgical measurement techniques, several investigators have used microneurography to record from the Ia and II fibres in humans during tendon vibration. In these studies the muscle spindle primary (Ia) endings are stimulated using transverse vibration of the tendon at reflex sub-threshold amplitudes. Others have used low amplitude vibration and the H-reflex (monosynaptic electrical response) to determine reflex properties during both agonist and antagonist voluntary contractions. Both of these methods explore only certain parts of the monosynaptic reflex arc; microneurography focus on the properties and firing characteristics of the muscle spindles themselves, whereas the H-reflex response to vibration is a representation of the response of the spinal cord as well as the muscle spindles. </p> <p> In the past we have developed a PC based instrument that uses Lab VIEW and a linear servomotor to study tendon reflex properties by recording H-reflexes (or stretch reflexes for mechanical stimuli) from single tendon taps or electrical stimuli to the afferent nerve. In this thesis we describe a further development of this system to provide precise vibrations of the tendon at up to 55 Hz with amplitudes up to 4 mm. The resultant vibration stretch reflex train is extracted from 2 major background noise sources, 60 Hz power line noise, and vibration artifact noise, of the EMG recording via phase coherent subtractive filtering. </p> <p> To demonstrate the versatility and efficacy of this system in studying the monosynaptic reflex arc, test results from several pilot studies are presented, using the system to vibrate the human distal flexor carpi radialis tendon: (i) whether stretch reflexes could be entrained with high frequency vibration, as contrary to H-reflexes, (ii) whether the responses were affected by low levels of agonist or antagonist contraction, in agreement with the existing pool of work on the subject using the H-reflex, (iii) whether a separation of the Ia (primary) and II (secondary) ending pathways is observable as individual but delayed responses at low vibration frequencies due to different activation characteristics, and axon diameters, of each ending. Possible physiological mechanisms that explain the resultant behaviour are also discussed. </p> / Thesis / Master of Applied Science (MASc)