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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
491

Sensing the environment : development of monitoring aids for persons with profound deafness or deafblindness

Ranjbar, Parivash January 2009 (has links)
Earlier studies of persons with deafness (D) and/or deafblindness (DB) have primarily focused on the mobility and communication problems. The purpose of the present study was to develop technology for monitoring aids to improve the ability of persons with D and/or DB to detect, identify, and perceive direction of events that produce sounds in their surroundings. The purpose was achieved stepwise in four studies. In Study I, the focus was on hearing aids for persons with residual low frequency hearing. In Study II-IV, the focus was on vibratory aids for persons with total D. In Study I, six signal processing algorithms (calculation methods) based on two principles, transposition and modulation, were developed and evaluated regarding auditory identification of environmental sounds. Twenty persons with normal hearing listened to 45 environmental sounds processed with the six different algorithms and identified them in three experiments. In Exp. 1, the sounds were unknown and the subjects had to identify them freely. In Exp. 2 and 3, the sounds were known and the subjects had to identify them by choosing one of 45 sounds. The transposing algorithms showed better results (median value in Exp. 3, 64%-69%) than the modulating algorithms (40%-52%) did, and they were good candidates for implementing in a hearing aid for persons with residual low frequency hearing. In Study II, eight algorithms were developed based on three principles, transposition, modulation, and filtration – in addition to No Processing as reference, and evaluated for vibratory identification of environmental sounds. The transposing algorithms and the modulating algorithms were also adapted to the vibratory thresholds of the skin. Nineteen persons with profound D tested the algorithms using a stationary, wideband vibrator and identified them by choosing one of 10 randomly selected from the list of 45 sounds. One transposing algorithm and two modulating algorithms showed better (p<0.05) scores than did the No Processing method. Two transposing and three modulating algorithms showed better (p<0.05) scores than did the filtering algorithm. Adaptation to the vibratory thresholds of the skin did not improve the vibratory identification results. In Study III, the two transposing algorithms and the three modulating algorithms with the best identification scores in Study II, plus their adapted alternative, were evaluated in a laboratory study. Five persons from Study II with profound D tested the algorithms using a portable narrowband vibrator and identified the sounds by choosing one of 45 sounds in three experiments (Exp. 1, 2, and 3). In Exp. 1, the sounds were pre-processed and directly fed to the vibrator. In Exp. 2 and 3, the sounds were presented in an acoustic test room, without or with background noise (SNR=+5 dB), and processed in real time. Five of the algorithms had acceptable results (27%-41%) in the three experiments and constitute candidates for a miniaturized vibratory aid (VA). The algorithms had the same rank order in both tests in the acoustic room (Exp. 2, and 3), and the noise did not worsen the identification results. In Study IV, the portable vibrotactile monitoring aid (with stationary processor) for detection, identification and directional perception of environmental sounds was evaluated in a field study. The same five persons with profound D as in Study III tested the aid using a randomly chosen algorithm, drawn from the five with the best results in Study III, in a home and in a traffic environment. The persons identified 12 events at home and five events in a traffic environment when they were inexperienced (the events were unknown) and later when they were experienced (the events were known). The VA consistently improved the ability with regard to detection, identification and directional perception of environmental sounds for all five persons. It is concluded that the selected algorithms improve the ability to detect, and identify sound emitting events. In future, the algorithms will be implemented in a low frequency hearing aid for persons with low frequency residual hearing or in a fully portable vibratory monitoring aid, for persons with profound D or DB to improve their ability to sense the environment.
492

Orchestration de l'auto-assemblage et des mouvements moléculaires de pseudo-rotaxanes helicoïdaux / Orchestration of the self-assembly and molecular motion of helical pseudorotaxanes

Wang, Xiang 28 June 2016 (has links)
L’orchestration des mouvements directionnels d’architectures supramoléculaires s’avère cruciale pour la préparation de machines moléculaires artificielles. Les oligomères d’amides aromatiques (i.e. foldamères) peuvent adopter des conformations stables capables de se complexer à des tiges moléculaires pour former des (pseudo)-rotaxanes. Un contrôle fin des cinétiques d’association et de dissociation de l’hélice autour de la tige permet à l’oligomère hélicoïdal de glisser le long de celle-ci sans dissociation. Des études RMN et cristallographiques ont montré que des tiges moléculaires possédant plusieurs sites de reconnaissance pour des hélices permettaient l’élaboration d’architectures supramoléculaires hélicoïdales chirales avec une haute-fidélité. Chaque station possédant une longueur et une chiralité définie peut induire la complexation de foldamères de taille et d’hélicité concordante. Le glissement directionnel d’une double hélice le long d’une tige possédant plusieurs stations a également été investigué. Insérer un espaceur encombrant (i.e. plus large que la cavité de l’hélice) sur le chemin du foldamère le force à se déplier et se replier pour atteindre le site le plus favorable thermodynamiquement. Un oligomère asymétrique montrant de hautes affinités et de fortes sélectivités pour des tiges asymétriques a été préparé. L’enfilement de cet oligomère sur des tiges asymétriques a été étudié. Des données cinétiques (RMN) indiquent que l’enfilement de celui-ci s’effectue de façon polarisée en fonction de la nature de la tige. / The directional motion orchestration of supramolecular architectures is crucial for the construction of artificial molecular machines. Aromatic amide oligomers (i.e. foldamers) can adopt stable helical conformations able to wind around dumbbell-like guests to form (pseudo)-rotaxanes. A fine control of the association-dissociation kinetics allows the oligomers to slide along the rods without dissociation. In this thesis, based on the segregation of the kinetics of association-dissociation and sliding, helical oligomer motions were orchestrated to form complex self-assemblies and to perform directional motion. NMR and crystallographic studies showed that multistation rod guests can template the formation of well-defined multi-helical supramolecular polymers with high fidelity. Each station possessing a defined length and chirality can induce the complexation of oligomers presenting matching length and chirality. Directional sliding of a double helical oligomer along linear multistation rod guests was investigated. Placing a bulky spacer on the rod prohibits the sliding process, forcing the oligomer to dissociate and reassociate onto the thermodynamically favored station. An asymmetrical oligomer was prepared showing highly selective binding toward asymmetrical rod guests. The threading of this oligomer onto linear asymmetrical guests was investigated. Kinetic data indicated that the threading orientation of this asymmetrical oligomer was polarized by its passage along guest molecules.
493

OMNI-DIRECTIONAL INFRARED 3D RECONSTRUCTION AND TRACKING OF HUMAN TARGETS

Benli, Emrah 01 January 2017 (has links)
Omni-directional (O-D) infrared (IR) vision is an effective capability for mobile systems in robotics, due to its advantages: illumination invariance, wide field-of-view, ease of identifying heat-emitting objects, and long term tracking without interruption. Unfortunately, O-D IR sensors have low resolution, low frame rates, high cost, sensor noise, and an increase in tracking time. In order to overcome these disadvantages, we propose an autonomous system application in indoor scenarios including 1) Dynamic 3D Reconstruction (D3DR) of the target view in real time images, 2) Human Behavior-based Target Tracking from O-D thermal images, 3) Thermal Multisensor Fusion (TMF), and 4) Visual Perception for Social Cognition from the motion behavior of the human target.
494

Att flytta periferin mot mittpunkten: riktningsekvivalens och representationell rättvisa i översättning från japanska till svenska : En partiell översättning från japanska till svenska med en översättningsteoretisk kommentar av IMAMURA Natsukos bok, Kvinnan i den lila kjolen (むらさきのスカートの女, Murasaki no sukaato no onna) / Bringing The Periphery To The Center: Directional Equivalence and Representational Justice for translating from Japanese to Swedish. : Translation and commentary of IMAMURA Natsuko’s novel むらさきのスカートの女 (Murasaki no sukaato no onna)

Liberman, Therése January 2020 (has links)
Den här magisteruppsatsen består av en partiell översättning från japanska till svenska av IMAMURA Natsukos bok Kvinnan i den lila kjolen samt en översättningskommentar med fokus på kulturspecifika kategorier uttryckt i det japanska språket som egocentriciteten och andra kulturspecifika element i den japanska texten, de beskrivande onomatope (onomatopoetiska och mimetiska uttryck), och de västerländska låneordens förskjutningar (shifts) i en översättning. Dessa kategorier kan upplevas som svåra att översätta mellan två språk som ligger långt ifrån varandra. De teoretiska ramarna för uppsatsen lägger tyngdpunkten på riktningsekvivalens (directional equivalence), ett begrepp myntat av Anthony Pym, med fokus på likhet (similarities) i översättningen (Chesterman 1996), tillsammans med den etiska utgångspunkten representationell rättvisa (representational justice), beskrivet av Liu Yameng (2007). De utgör basen för översättningsmetoden och blir ledljus i översättningsval för översättning mellan språk i periferin av varandra. / This essay consists of a partial translation of IMAMURA Natsuko’s book The Woman In The Purple Skirt from Japanese to Swedish, together with a translation commentary focusing on egocentricity and other culture-specific concepts in Japanese texts, the descriptive onomatope (onomatopoetic and mimetic expressions) and the shifts in loanwords from western languages when translated. These categories are prone to cause issues when translating between languages so far removed from each other. The theoretical framework in this essay concentrates on directional equivalence, an expression coined by Anthony Pym, focusing on similarities in translations (Chesterman 1996) together with the ethical starting point representational justice as described by Liu Yameng (2007). These form the base for the translation method and serve as guiding lights in the choices made when translating between languages peripheral to each other.
495

Examination of a Bi-Directional Relationship between Urgency and Alcohol Use

Blackledge, Sabrina M. 12 1900 (has links)
The proposed study examined whether negative urgency and positive urgency are dynamic traits that hold bi-directional relationships with binge and prolonged alcohol use across time. Individuals between the ages of 18-30 were recruited from Amazon Mechanical Turk (MTurk; n = 179) and university student (n = 66) pools. Participants completed three batteries of self-report assessments approximately 30 days apart, each containing measures assessing negative and positive urgency, as well as drinking frequency and binge behavior during the prior month. Latent variable cross-lagged panel models examined the effects of alcohol use from the previous month on negative and positive urgency while controlling for concurrent and autoregressive effects. Results of the current study indicated that for the full sample, there was not an effect for the influence of binge/prolonged drinking on either negative or positive urgency during the subsequent month. However, when examined separately by sample (Turkers vs. university) and gender (male vs. female), significant effects were found more for individuals who were Turkers, male, and/or heavy drinkers, suggesting that increases in positive and negative urgency at Time 2 could be partially explained by variance in drinking patterns at Time 1 for these individuals. However, these relationships were not replicated again between Time 2 and Time 3 due to a decrease in all drinking behaviors during these times. Lastly, the study found that while urgency scores were related to psychosocial problems and dependence symptoms associated with drinking, there was no evidence to support that urgency scores had substantial relationships to specific frequency and/or bingeing behavior across the overall sample, although positive urgency had support for a relationship with bingeing, particularly among heavily drinking men. Thus, while the primary findings did not indicate any effects for a general sample of young adults, the effects observed among heavy male drinkers in the present study add to a growing body of literature indicating potential for interactive effects among personality, environmental, and sociobiological factors across the trajectory of the human lifespan. Future research that continues to examine urgency and how it relates to alcohol use in longitudinal contexts, utilizing diverse samples, is warranted.
496

Vliv polohy reproduktorů na charakteristiky reproduktorové soustavy / Influence of drivers position on the characteristics of the loudspeaker system

Bičan, Jan January 2021 (has links)
This thesis deals with the measurement and description of properties of the two-way variable modular loudspeaker system marked as OM-3, especially the influence of the mutual position of drivers on its characteristics. The thesis examines individual factors taking their contribution on characteristics of the loudspeaker system in total. Further it measures and evaluates options of compensations of mutual position changes of drivers using an all-pass filter. Within this thesis is also included laboratory task preparation which is focused on this problematics.
497

Growth and characterization of phosphorus-doped silicon for photovoltaic application directionally solidified under the influence of different process conditions

Buchovska, Iryna 14 December 2021 (has links)
In dieser Arbeit werden Möglichkeiten zur Homogenisierung von Widerstandsprofilen entlang von phosphordotierten, gerichtet erstarrten, multikristallinen Silizium (mc-Si) Blöcken für PV-Anwendungen untersucht. Die im Rahmen der Dissertation durchgeführte analytische Untersuchung konzentriert sich auf den Phosphortransport in der Siliziumschmelze, an der Grenzfläche zwischen Kristall und Schmelze, an der Schmelzenoberfläche und in der Gasphase oberhalb der Schmelze. Es wurden drei Prozessparameter identifiziert, die den stärksten Einfluss auf die Phosphorverteilung in multikristallinen Blöcken haben: die Durchmischung der Schmelze, der Gesamtgasdruck in der Anlage und der Gasfluss über der Schmelze. Variationen in der Stärke der TMF sind sinnvoll, um die Phosphorverteilung entlang der Barrenhöhe zu beeinflussen. Ein schwaches TMF bewirkt eine gleichmäßigere Dotierstoffverteilung und führt zu einem verringerten spezifischen Widerstand des Blocks in den Anfangsstadien der Kristallisation, während ein starkes TMF einen signifikanten Effekt auf die Phosphorverdampfung hat und zu einem Anstieg des spezifischen Widerstandes zum Ende des Blocks hin führt. Die Ergebnisse der Experimente zeigten, dass die Verringerung des Gasdrucks zu einer deutlich verstärkten Phosphorverdampfung von der freien Schmelzenoberfläche führt und damit den spezifischen Widerstand des erstarrten Blocks erhöht, vor allem gegen dessen Ende hin. Die während der Studie gewonnenen Erkenntnisse wurden für die Optimierung der typischen G1-Wachstumsrezeptur verwendet. Die mit diesem Rezept gezüchteten G1 mc-Si Blöcke zeigen eine gleichmäßigere Widerstandsverteilung als solche, die mit einem typischen Rezept gezüchtet wurden. Die Widerstandsvariation wurde auf 55 % verringert und erfüllte den von der Marktspezifikation vorgegebenen Zielbereich von 3,0 - 1,0 Ω·cm. Die entwickelte Rezeptur wurde erfolgreich für die gerichtete Erstarrung mit Keimvorgabe übertragen. / The research described in this thesis is focused on homogenization of resistivity profiles along phosphorus-doped directionally solidified multicrystalline silicon (mc-Si) ingots for PV application. The analytical study conducted within the framework of the thesis is focused on phosphorus transport in the silicon melt, at the crystal-melt interface, at the melt surface and in the gaseous phase above the melt. Three process parameters were identified to have the most dominant influence on phosphorus distribution in multicrystalline ingots: melt mixing, furnace ambient gas pressure and gas flow above the melt. It was found that variations in strength of TMF could be used to control the phosphorus distribution along the ingot’s length. Weak TMF provokes more uniform dopant distribution and results in decreased ingot resistivity at the initial stages of crystallization, while strong TMF has more prominent effect on phosphorus evaporation that leads to the increase of resistivity towards the ingot’s end. The results of experiments demonstrated that reduction of ambient gas pressure leads to significantly intensified phosphorus evaporation from the free melt surface and increases the resistivity of the solidified ingot, especially towards its end. The findings obtained during the study were used for the adjustment of the typical G1 growth recipe. Conventional G1 mc-Si ingots grown using this recipe show more uniform resistivity distribution than those grown using a typical one. Resistivity variation was reduced to 55% and met the target range of 3.0 – 1.0 Ω·cm set by market specification. The developed recipe was successfully replicated for directional solidification seeded growth.
498

Predikce Pohybu Bezdrátových Uzlů v Mobilních Ad Hoc Sítích (MANET) / Movement Prediction of Wireless Nodes in Mobile Ad Hoc Networks (MANETS)

Makhlouf, Nermin January 2019 (has links)
Rychlý vývoj v oblasti mobilní informatiky vyústil v nový, alternativní způsob mobilní komunikace, v němž mobilní uzly tvoří samoorganizující se bezdrátovou síť, jíž se říká mobilní síť ad hoc (Mobile Ad hoc Network, MANET). Specifické vlastnosti sítí MANET stavějí návrh síťového protokolu před řadu problémů na všech vrstvách protokolové sady . Příčinou jsou nepředvídatelné změny topologie a mobilní povaha těchto sítí. Nástrojem, který řeší problémy plynoucí z mobility uzlů, je predikce budoucích změn v topologii sítě. To má zásadní význam pro různé úlohy jako přesměrování. Tato disertační práce se zabývá dvěma metodami predikce mobility pro sítě MANET. První metoda se nazývá „predikce mobility s využitím virtuální mapy“ (mobility prediction using virtual map) a předpokládá, že každý uzel si dokáže vybudovat svou virtuální mapu v závislosti na svém umístění v průběhu času. Vyvinutý predikční algoritmus byl implementován do síťového simulátoru NS-2, aby jej bylo možné vyhodnotit. V této práci zkoumám stávající modely mobility a způsob, jakým v nich lze aplikovat tuto metodu predikce. Simulace sledují zlepšení výkonnosti, co se týče průměrného zpoždění na bázi end-to-end, poměru doručených paketů a propustnosti sítě. Navržený koncept predikce byl implementován pomocí směrovacího protokolu AODV(Ad Hoc On-Demand Distance Vector). Pro druhou metodu jsem vyvinula umělou neuronovou síť pro predikci pohybů v sítích MANET. Model pro predikci mobility vznikl na základě dat shromážděných ze vzorců umístění. K učení či trénování ANN byl využit bayesovský přístup. Ten byl implementován v softwaru pro trénování bayesovských neuronových sítí s názvem Model Manager. Nejlepším způsobem hodnocení závěrečného modelu je provedení predikcí a jejich srovnání s cílovými daty. Predikce vznikají na základě 50 vzorců jako vstupních proměnných. Dosažené výsledky prezentované s diskutované v práci se vyznačují zlepšením zásadních parametrů komunikační sítě, jako jsou propustnost, zpoždění, Poměr doručených paketů, až o 30% v porovnání s klasickým směrovacím protokolem AODV, kde není implementován predikční model.
499

Modulární systém pro měření charakteristik dvoupásmových reproduktorových soustav / Modular system for measuring the characteristics of two-way loudspeaker systems

Pešek, Marko January 2019 (has links)
This master's thesis deals with design and implementation of modular system for two-way loudspeaker system's characteristics. Work focus mainly on the enclosure geometry and speaker placement. The individual modules of the system were designed and then implemented. Furthermore, the characteristics of these modules were measured and laboratory tasks using these modules were elaborated.
500

Analýza vlivu směrové distribuce kolagenních vláken ve stěně tepny na její mechanické vlastnosti / Analysis of impact of direction distribution of collagen fibres in arterial wall on its mechanical properties

Fischer, Jiří January 2020 (has links)
The aim of this thesis is to analyse literature with focusing on literature about directional distribution of collagen fibres. This knowledge is very important for computational modelling and FEM analysis of arterial wall. Comparison of suitability of different models of directional distribution of collagen fibres is made by fitting of different types of probability density functions. Impact assessment of different collagen fibres distribution on mechanical properties of the arterial wall and impact assessment of wall anisotropy is solved with finite element method. FEM analysis is done on three loading types – uniaxial tension, equibiaxial tension and inflation of artery by internal pressure. Output of this thesis is evaluation of results for various types of collagen fibres arrangement in arterial wall.

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