Thesis (M.S.)--Brigham Young University. Dept. of Civil and Environmental Engineering, 2003. / Includes bibliographical references (p. 93-94).

An approach based on the estimation of the coherence using wavelet analysis is applied to EEG and ERP signals for the detection of pathological patterns related with dyslexia. Coherence can be defined as the correlation of two signals in the frequency domain. The continuous wavelet transform was used for the computation of spectral characteristics since it provides highly overlapping windows which improve the reliability of the coherence estimate. This is achieved by increasing the number of segments over which the spectrum is averaged and thereby half of the amount of data is needed. Statistical analysis of the results revealed significant differences between controls and dyslexics in EEG(F3 gamma band), ERP-P50H(F3 gamma band) and attentive ERP-N100L(F3, C3 and Cz alpha band). It has also been shown that there are significant differences related with handiness and age. It is believed that signal recording from these electrodes may reflect brain areas concerning auditory and memory processing. / -

The principal of works means and reception of the solution, used for the investigation of rails flaw do not change. Even the newest microprocessor systems of rails’ flaw detection which is found in the latest year uses the simplest criteria’s, that are the amplitude of the reflected ultrasound signal and delaying time. While computer and microprocessor technology improves, the means of numerical measurement and possibilities of processing data, that is signals capable to measure the large majority of the more difficult structure and the algorithm or functions, are found out. The widest classification of the objects is used for identifications’ solution based on separating random processes. The acoustic diagnostic of engines and mechanics, sound and ultrasound defectoscopy, and objects’ identification in accordance with spread signals’ of noise that are in the random background and etc. are named in all those areas where the method of random processes’ classification is suitable.

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<p>Researchers have long assumed that black widow coloration functions as a warning signal to avian predators. However adult female black widow coloration does not resemble typical warning coloration in two distinct ways. First, black widows are less colorful than most other documented aposematic species. Second, the hourglass shape of an adult female varies both between species and within a site. Here I examine the ultimate causes and consequences of North American black widow coloration. </p><p>In chapter two I present data that suggest that black widow coloration not only functions as an aposematic signal to avian predators, but has also been selected to be inconspicuous to insect prey. In choice experiments with wild birds, I found that the red-and-black coloration of black widows deters potential predators: wild birds were ~3 times less likely to attack a black widow model with a red hourglass than one without. Using visual-system appropriate models, I also found that a black widow's red-and-black color combo is more apparent to a typical bird than typical insect (Euclidean color distance ~2.2 times greater for birds than insects). Additionally, an ancestral reconstruction revealed that red dorsal coloration is ancestral in black widows and that at some point some North American black widows lost their red dorsal coloration (while maintaining the ventral hourglass). Behaviorally, differences in red dorsal coloration between two North American species are accompanied by differences in microhabitat that affects how often a bird will view a black widow's dorsal region. All observations are consistent with a cost-benefit tradeoff of being conspicuous to potential predators while being inconspicuous to prey. I suggest that avoiding detection by prey --- combined with Müllerian mimicry --- may help explain why red-and-black aposematic signals occur frequently in nature.</p><p>In chapter three, I examine the variation in hourglass shape. Classical aposematic theory predicts near uniformity in warning signal appearance because a uniform signal is easier to learn to avoid than a variable signal. However the shape of the hourglass of North American black widows appears to vary both within and between sites in ways that are inconsistent with classical aposematic theory. Using 133 black widows of three different species from nine sites across the United States, I quantified the variation in hourglass shape and examined how Müllerian mimicry, species type, and condition each influenced hourglass shape. A principle components analysis revealed that 84.5% of the variation in hourglass shape can be explained by principle components 1, 2, and 3, which corresponded to hourglass size (PC1), the separation between hourglass parts (PC2), and the slenderness of the hourglass (PC3). Both a black widow's condition and species significantly predicted hourglass shape; however I found no support for localized Müllerian mimicry within different geographical regions. My results suggest a relaxed role for selection on hourglass shape. I discuss several hypotheses that could explain the variation in hourglass morphology including that potential predators may avoid any red markings rather than an exact shape (categorical rather than continuous perception).</p><p>In chapter four I expand on my work from chapter two to examine the eavesdropper's perspective on private communication channels. Private communication may benefit signalers by reducing the costs imposed by potential eavesdroppers such as parasites, predators, prey, or rivals. It is likely that private communication channels are influenced by the evolution of signalers, intended receivers, and potential eavesdroppers, but most studies only examine how private communication benefits signalers. Here, I address this shortcoming by examining visual private communication from a potential eavesdropper's perspective. Specifically, I ask if a signaler would face fitness consequences if a potential eavesdropper could detect its signal more clearly. By integrating studies on private communication with those on the evolution of vision, I suggest that published studies find few taxon-based constraints that could keep potential eavesdroppers from detecting most hypothesized forms of visual private communication. However, I find that private signals may persist over evolutionary time if the benefits of detecting a particular signal do not outweigh the functional costs a potential eavesdropper would suffer from evolving the ability to detect it.</p> / Dissertation

Various writing devices are designed to serve specialized purposes or “functions” to aid readers in their processing of a text. For example, an index lists important topics in the book and allows the readers to quickly locate the pages relevant to a particular topic. The purpose of this study was to learn what mature readers know about various functional devices. Two experiments were conducted to learn what readers know about functional devices in texts. Experiment 1 investigated readers’ knowledge about functional writing devices and Experiment 2 examined readers’ beliefs about the relevance of functional writing devices in various reading situations. At the end of the experiments, a list of functional writing devices and their respective usage was created from the results of Experiment 1 & 2. The information obtained could be useful for education purposes and also future studies on the effects of function identifying signals on cognition.

Despite having the numerous evolved heart rate measuring devices and progress in their development over the years, there always remain the challenges of modern signal processing implementation by a comparatively small size wearable device. This thesis paper presents a wearable reflectance photoplethysmography (PPG) sensor system for measuring the heart rate of a user both in steady and moving states. The size and, power consumption of the device are considered while developing, to ensure an easy deployment of the unit at the measuring site and the ability to power the entire unit with a battery .The selection of both the electronic circuits and signal processing techniques is based on their sensitivity to PPG signals, robustness against noise inducing artifacts and miniaturization of the entire measuring unit. The entire signal chain operates in the discrete-time, which allows the entire signal processing to be implemented in firmware on an embedded microprocessor. The PPG sensor system is implemented on a single PCB that consumes around 7.5mW of power. Benchmarking tests with standard heart rate measuring devices reveal that the developed measurement unit (combination of the PPG sensor system, and inertial measurement unit (IMU) developed in-house at Acreo Swedish ICT, and a battery) is comparable to the devices in detecting heart rate even in motion artifacts environment. This thesis work is carried out in Acreo Swedish ICT, Gothenburg, Sweden in collaboration with MidSweden University, Sundsvall, Department of Electronics Design. This report can be used as ground work for future development of wearable heart rate measuring units at Acreo Swedish ICT.