Design and testing of the system for localizing a sound source

Tato bakalsk prce se zabv monostmi lokalizace zdroje zvuku. Na zaÄtku jsou obecnÄ zm­nÄna mon hardwarov i softwarov een­, z nich jsou vybran© dvÄ pouiteln© metody a vhodn© komponenty testovac­ho za­zen­. Dle navazuje praktick Äst prce, kde jsou naprogramovan© algoritmy popsan©. Dleitou souÄst­ je nsledn© testovn­. Pro vybran© mikrofonn­ pole je otestovna pesnost v zvislosti na zmÄnÄ poÄtu a rozm­stÄn­ senzor, vlivu okoln­ho ruen­ a na um­stÄn­ pekky v prostoru. Vstupem test je zhodnocen­ funkÄnosti a pesnosti pro obÄ pouit© metody.This bachelorâs thesis deals with possibilities of sound source localization. There are generally mentioned possible hardware and software solutions at the beginning, from which two applicable methods and suitable components of test device are selected. Further there is a practical part of this work, where programmed algorithms are described. An essential part is testing. Accuracy is tested for the selected microphone array, depending on the change in the number and position of the sensors, the effect of ambient noise, and the location of the obstacle in the area. The output of the tests is the evaluation of functionality and accuracy for both methods used.

Listening in large rooms : a neurophysiological investigations of acoustical conditions that influence speech intelligibility

Thesis (M.S.)--Massachusetts Institute of Technology, Whitaker College of Health Sciences and Technology, 1997.Includes bibliographical references (p. 34-37).by Benjamin Michael Hammond.M.S

Influência de diferentes curvas de congelação sobre a integridade do acrossoma de células espermáticas de sémen caprino

Dissertação de Mestrado, Engenharia Zootécnica, 9 de Julho de 2013, Universidade dos Açores.O presente trabalho teve como objectivo testar o efeito de 3 curvas de congelaçao diferentes sobre a integridade do acrossoma da célula espermática de caprinos. A colheita de sémen foi realizada nos Serviços de Desenvolvimento Agrário da Ilha Terceira (SDAT), tendo sido utilizados 3 bodes (2 de raça Saanen e 1 de raça Alpina) com mais de 2 anos de idade. As recolhas (3 por cada animal) foram efectuadas durante o mês de Fevereiro de 2012, em 3 sessões espaçadas de aproximadamente 5 dias, seguindo um desenho factorial de medições repetidas. As recolhas foram sempre efectuadas pela manhã, com inicio por volta das 08:00 horas e em cada período de colheita os bodes alternavam aleatoriamente. A colheita do sémen foi obtida com vagina artificial, após treino dos bodes, utilizando uma fêmea com cio induzido. A indução artificial do cio foi conseguida com uma injecção intramuscular de 250 μg de benzoato de estradiol diluído em 2 ml de óleo mineral, aplicada 24 a 48 horas antes do momento necessário, seguida de uma nova injecção passadas 24 horas na dose de 100 μg de modo a garantir o prolongamento do cio pelas próximas 24 horas. No laboratório procedeu-se à avaliação de características seminais como o volume, a concentração espermática e a mobilidade massal. De seguida efectuou-se a contagem dos espermatozóides vivos e mortos por citometria de fluxo e procedeu-se à congelação do sémen segundo as 3 curvas, que diferiam nas rampas de arrefecimento. As temperaturas das diferentes curvas foram iguais, variando apenas a temperatura de arrefecimento na segunda rampa (Curva A = 25 ºC/min, Curva B = 35 ºC/min e Curva C = 45 ºC/min). Para testar a influência das referidas curvas sobre a integridade do acrossoma recorreu-se novamente ao citómetro e determinou-se a percentagem de espermatozóides vivos e mortos e com o acrossoma intacto ou danificado. As diferentes curvas não influenciaram significativamente a taxa de mortalidade dos espermatozóides com acrossoma intacto (11,6 ± 0,63 % spz Curva A, 11,36 ± 0,63 % spz Curva B e 10,37 ± 0,63 % spz Curva C) ou danificado (68,78 ± 1,39 % spz Curva A, 70,54 ± 1,39 % spz Curva B e 70,96 ± 1,39 % spz Curva C). No entanto observou-se um efeito significativo dos bodes e dias de colheita nos quatro parâmetros estudados - percentagem de espermatozóides vivos com o acrossoma intacto (VAI) ou danificado (VAD) e percentagem de espermatozóides mortos com o acrossoma intacto (MAI) ou danificado (MAD). Relativamente à percentagem de espermatozóides VAI o bode 1 apresentou valores 50% inferiores aos bodes 2 e 3 (P<0.001) e o dia de colheita afectou substancialmente este parâmetro (25,33 ± 0,66 % spz dia colheita 1, 18,40 ± 0,66 % spz dia colheita 2 e 11,31 ± 0,91 % spz dia colheita 3; P<0.01). A percentagem de espermatozóides VAD diferiu significativamente entre o animal 1 e 2 (P=0,016) e entre os dias de colheita 1 e 3 (P=0,032). No que se refere à percentagem de espermatozóides mortos, os factores animal e dia de colheita também afectaram significativamente os resultados. O bode 1 diferiu significativamentedos dos restantes na percentagem de espermatozóides MAI. Também para este parâmetro, os dias de colheita 2 e 3 revelaram-se significativamente diferentes (P=0,042). Na percentagem de espermatozóides MAD o bode 1 diferiu dos bodes 2 e 3 (P<0,001). Neste parâmetro verificaram-se diferenças significativas entre o dia 1 e os dias 2 (P=0,003) e 3 (P<0,001). Os resultados deste ensaio permitiram concluir que as 3 curvas de congelação estudadas não influenciaram significativamente as taxas de mortalidade dos espermatozóides do sémen de caprino, sugerindo que qualquer delas se revelou eficaz na congelação de sémen desta espécie. Verificou-se no entanto uma variação significativa, quer entre animais quer entre dias de colheita, reafirmando estes factores como bastante influenciadores da variabilidade frequentemente observada das capacidades fertilizantes do sémen congelado de caprino.ABSTRACT: This study was aimed to test the effect of 3 different freezing curves on the acrosome integrity of male goat sperm cell . The semen collection was performed at the Departments of Agrarian Development of Terceira Island (SDAT), using 3 bucks (2 Saanen and 1 Alpine breed) aged more than 2 years . Collections (3 per animal) were carried out during February 2012 in three sessions with 5 day-intervals, following a factorial experimental design with repeated measures. The collections were always made in the mornings, starting at around 08: 00 hours and during each collection period the bucks alternated randomly. The semen was collected with an artificial vagina after the bucks had been trained, with a female induced in heat. The artificial induction of heat was achieved with an intramuscular injection of 250 μg of oestradiol benzoate dissolved in 2 ml of mineral oil applied 24 to 48 hours prior to be necessary, followed by a further injection applied 24 hours after, at a dose of 100 μg in order to ensure the continuation of the heat for the next 24 hours. In the laboratory, took place the evaluation of seminal characteristics like volume, sperm concentration and massal mobility. After the counting of live and dead sperm by flow cytometry, the procedures followed with the freezing of semen according to the three curves, which differed in ramp cooling. The temperatures of the different curves were similar, varying only in the temperature of the second cooling ramp (Curve A = 25 ° C / min, Curve B = 35 ° C / min and Curve C = 45 ° C / min). To test the influence of the curves on the acrosome integrity the cytometer was used again to determine the percentage of live and dead spermatozoa and the acrosome integrety. The different curves did not influence the mortality rate of sperm with intact acrosome (11,6 ± 0,63 % spz Curve A, 11,36 ± 0,63 % spz Curve B e 10,37 ± 0,63 % spz Curve C) or damagedo (68,78 ± 1,39 % spz Curve A, 70,54 ± 1,39 % spz Curva B e 70,96 ± 1,39 % spz Curva C). However there was a significant effect of bucks and collection days in the four parameters studied - percentage of live sperm with intact (VAI) or damaged (VAD) acrosome and percentage of dead sperm with intact (MAI) or damaged (MAD) acrosome. Concerning the percentage of VAI sperm male goat 1 showed values 50% lower than goats 2 and 3 (P <0.001) and collection day substantially affected this parameter (25.33 ± 0.66% SPZ collection day 1, 18.40 ± 0.66% SPZ collection day 2 and 11.31 ± 0.91% SPZ collection day 3; P <0.01). The percentage of sperm VAD differed significantly between animals 1 and 2 (P = 0.016) and between collection days 1 and 3 (P = 0.032). Regarding the percentage of dead spermatozoa, animal and collection day factors also significantly affected the results. Buck 1significantelly differed in the percentage of MAI spermatozoa. Also for this parameter, the collection days 2 and 3 were significantly different (P = 0.042). In percentage of the MAD spermatozoa buck 1 differed from bucks 2 and 3 (P <0.001). In this parameter, there were significant differences between day 1 and day 2 (P = 0.003) and 3 (P <0.001). The results of this experiment showed that the 3 freezing curves studied did not significantly influence the mortality rates of male goat spermatozoa , suggesting that any of them proved effective in freezing semen of this species. There was however a significant variation between animals and between collection days, confirming these as very influencing factors of the variability commonly observed in the fertilization ability of male goat semen

Auditory edge detection: the dynamics of the construction of auditory perceptual representations

This dissertation investigates aspects of auditory scene analysis such as the detection of a new object in the environment. Specifically I try to learn about these processes by studying the temporal dynamics of magnetic signals recorded from outside the scalp of human listeners, and comparing these dynamics with psychophysical measures. In total nine behavioral and Magneto-encephalography (MEG) brain-imaging experiments are reported. These studies relate to the extraction of tonal targets from background noise and the detection of change within ongoing sounds. The MEG deflections we observe between 50-200 ms post transition reflect the first stages of perceptual organization. I interpret the temporal dynamics of these responses in terms of activation of cortical systems that participate in the detection of acoustic events and the discrimination of targets from backgrounds. The data shed light on the statistical heuristics with which our brains sample, represent, and detect changes in the world, including changes that are not the immediate focus of attention. In particular, the asymmetry of responses to transitions between 'order' and 'disorder' within a stimulus can be interpreted in terms of different requirements for temporal integration. The similarity of these transition-responses with commonly observed onset M50 and M100 auditory-evoked fields allows us to suggest a hypothesis as to their underlying functional significance, which so far has remained unclear. The comparison of MEG and psychophysics demonstrates a striking dissociation between higher level mechanisms related to conscious detection and the lower-level, pre-attentive cortical mechanisms that sub-serve the early organization of auditory information. The implications of these data for the processes that underlie the creation of perceptual representations are discussed. A comparison of the behavior of normal and dyslexic subjects in a tone-in-noise detection task revealed a general difficulty in extracting tonal objects from background noise, manifested by a globally delayed detection speed, associated with dyslexia. This finding may enable us to tease apart the physiological and behavioral corollaries of these early, pre-attentive processes. In conclusion, the sum of these results suggests that the combination of behavioral and MEG investigative tools can provide new insights into the processes by which perceptual representations emerge from sensory input