The current behavioural dead region (DR) diagnosis methods such as psychophysical tuning curves and the threshold-equalising noise test require extensive subject co-operation. These present methods cannot be applied to infants. The work presented in the thesis aimed to develop a fast objective DR diagnosis method that could be applied to sleeping hearing-impaired infants. A novel fast objective electrophysiological method of recording response amplitude curves (RACs) which could enable objective DR diagnosis was developed.RACs were derived by recording auditory steady-state response amplitudes using modulated signals in the presence of narrow-band maskers. Two RAC methods were investigated. In the swept method, RACs were recorded in a single test run by recording the response amplitudes across the frequency range of a continuously swept-frequency narrow-band masker. In the fixed method, response amplitudes of eight separate test runs, each in the presence of differing fixed-frequency narrow-band maskers, were recorded.RACs were recorded in normally hearing adult subjects. The results showed that for normally hearing subjects in condition 1 (swept masker), the mean recorded RAC tip for a 2-kHz signal was 2250 Hz and the repeatability coefficient of two repeated recordings in each subject was 389 Hz; in condition 2 (fixed masker), the respective values were 2251 Hz and 342 Hz. These results indicated that the swept masking method is a viable and fast way to record RACs in normally hearing adults.RACs and psychophysical tuning curves (PTCs) were recorded in hearing-impaired adult subjects in order to asses the tip-frequency agreement between the tests. In some cases there were difficulties in using the required signal and masker levels due to maximum sound level limits. The RACs were poorly shaped and had poor repeatability. These findings indicate that the RAC method that was successfully applied to normally hearing subjects requires further development for use with the hearing impaired. The possible causes for the differences in the accuracy of the method between normally hearing and hearing-impaired subjects are discussed. The work presented in this thesis provides the basis upon which further research can be taken forward. It is envisaged that this work, together with further research, will lead to a clinically-effective objective DR diagnosis method.

This paper describes the IBM Power8 system in comparison to the Intel Xeon processors, widely used in today’s solutions. The performance is not evaluated only on the whole system level but also on the level of threads, cores and a memory. Different metrics are demonstrated on typical optimized algorithms. The benchmarked Power8 processor provides extremely fast memory providing sustainable bandwidth up to 145 GB/s between main memory and processor, which Intel is unable to compete. Computation power is comparable (Matrix multiplication) or worse (N-body simulation, division, more complex algorithms) in comparison with current Intel Haswell-EP. The IBM Power8 is able to compete Intel processors these days and it will be interesting to observe the future generation of Power9 and its performance in comparison to current and future Intel processors.

The problem with which this investigation is concerned is that of determining the steady-state and dynamic characteristics of the admittance of a metallic probe immersed in a laboratory plasma which has the low electron densities and low electron temperatures characteristic of the ionospheric plasma. The problem is separated into three related topics: the design and production of the laboratory plasma, the measurement of the steady-state properties of dc and very low frequency probe admittance, and the study of transient ion sheath effects on radio frequency probe admittance.

Maintenance and rehabilitation of existing masonry and reinforced concrete structures are of great importance in the field of civil engineering. Due to deterioration and severe environment, numerous structures fail to meet functional or safety requirements, and as a result, they should be strengthened. Several methods have been utilized to repair the structures, including steel plate bonding, cable post-tensioning, and section enlargement. However, these methods bring disadvantages, such as significant added dead load and high labour cost. Therefore, externally bonding with composite materials has attracted considerable attention recently. Externally bonded fibre-reinforced polymer (FRP) sheets have been widely used to strengthen reinforced concrete and masonry structures. FRP has been a common method to provide a higher service life for structures for several decades. However, strengthening structural members with FRP introduces certain drawbacks, such as their poor performance in fire scenarios caused by the rapid softening of the polymer-based resin. An alternative strengthening system known as a fabric-reinforced cementitious matrix (FRCM) has been developed to address this issue by replacing resin-based material with an inorganic cementitious-based matrix. Nonetheless, the performance of FRCM at high temperatures has not been investigated sufficiently so far. Hence, this research focused on the mechanical behaviour of FRCM at high temperatures. This experimental research investigates the tensile performance of carbon FRCM at high temperatures. First, the temperature distribution within the specimens during heating was studied using nine specimens with one, two, or three layers to reveal the required time for the inner fabric to reach a steady temperature. Then, the tension and stiffness degradation of FRCM coupons were studied at different temperatures. A total of 84 FRCM coupons were fabricated and tested in tension; 60 of the tests were conducted at steady-state conditions in which temperature was held constant and load increased, and 24 specimens were carried out in transient-state tests, in which load was constant, and temperature grew. In order to provide a more comprehensive knowledge concerning the FRCM composite, some key variables were included in this research. These parameters are the number of layers (1, 2, 3) leading to different thicknesses (20, 30, 40 mm), the orientation of the fabric layer (unidirectional and bidirectional), target temperature (ambient, 100, 200, 300, 400°C), and heating condition (steady-state, transient state). These tests aimed to reveal the primary mechanical characteristics such as ultimate strength and cracked elastic modulus at different temperatures and compare them with control specimens tested at room temperature. With the increase in the number of fabric grids from one to two and three, the stress at failure decreased by about 11 and 18%, respectively. With regards to cracked elastic modulus two and three-layered specimens showed 18 and 20% reduction in value. It is also noteworthy to mention that overall load capacity of specimens rose with the increase in number of layers; however, due to the more significant increase in area, the stress was reduced. The same decreases in the cracked elastic modulus and ultimate strength were observed as the target temperature increased. Increasing the temperature to 400°C led to a decrease in ultimate strength and cracked elastic modulus of approximately 60 to 70%. Furthermore, the bidirectional specimens showed a better behaviour than unidirectional specimens in terms of ultimate strength; however, their cracked elastic moduli were almost the same. With regards to the transient-state tests, as the material became thicker, the failure temperature increased considerably. For instance, a 20-mm specimen failed at 467°C with a 20% sustained load, while a 30-mm specimen failed at 558°C. Another vital parameter studied in transient-state tests was the decrease in temperature with the increase in sustained load. An example of this is the 20-mm specimens which failed at 352 and 258°C, while they were preloaded to 40 and 60% of their capacities. The conclusions of this study suggest that FRCM materials do retain a non-negligible strength capacity at high temperatures. However, further investigations to reveal FRCM bond behaviour and retrofitted structural members at high temperatures are still required to provide comprehensive knowledge.

Rationale: Schizophrenia patients consistently show deficits in sensory-evoked broadband gamma oscillations and click-evoked entrainment at 40 Hz, called the 40-Hz auditory steady-state response (ASSR). Since such evoked oscillations depend on cortical N-methyl D-aspartic acid (NMDA)-mediated network activity, they can serve as pharmacodynamic biomarkers in the preclinical and clinical development of drug candidates engaging these circuits. However, there are few test-retest reliability data in preclinical species, a prerequisite for within-subject testing paradigms. Objective: We investigated the long-term psychometric stability of these measures in a rodent model. Methods: Female rats with chronic epidural implants were used to record tone- and 40 Hz click-evoked responses at multiple time points and across six sessions, spread over 3 weeks. We assessed reliability using intraclass correlation coefficients (ICC). Separately, we used mixed-effects ANOVA to examine time and session effects. Individual subject variability was determined using the coefficient of variation (CV). Lastly, to illustrate the importance of long-term measure stability for within-subject testing design, we used low to moderate doses of an NMDA antagonist MK801 (0.025–0.15 mg/kg) to disrupt the evoked response. Results: We found that 40-Hz ASSR showed good reliability (ICC=0.60–0.75), while the reliability of tone-evoked gamma ranged from poor to good (0.33–0.67). We noted time but no session effects. Subjects showed a lower variance for ASSR over tone-evoked gamma. Both measures were dose-dependently attenuated by NMDA antagonism. Conclusion: Overall, while both evoked gamma measures use NMDA transmission, 40-Hz ASSR showed superior psychometric properties of higher ICC and lower CV, relative to tone-evoked gamma.

Theoretischer Hintergrund: Störungen des Körperbildes stellen einen der zentralen Risikofaktoren für die Entstehung und Aufrechterhaltung von Essstörungen dar. Gemäß der kognitiv-behavioralen Theorie für Körperbildstörungen führen körperbezogene Stimuli zu einer Aktivierung körperbezogener Schemata, welche zu Verzerrungen in kognitiven Prozessen führen können. Im Zuge der Untersuchung kognitiver Verzerrungen blieb bislang die Frage offen, ob sich kognitive Verzerrungen primär auf den eigenen Körper oder auf Körper generell erstrecken. Innerhalb dieser Dissertation wurde daher untersucht, ob die Identität eines Körpers evaluative, attentionale und perzeptive Prozesse der Körperverarbeitung beeinflusst. In den Studien 1 bis 3 wurde mittels eines Forschungsparadigmas zur Manipulation der Identität geprüft, ob Doppelstandards bei der Bewertung von Körpern in unterschiedlichen Populationen vorliegen. In Studie 4 wurde außerdem der attentionale Verlauf für den eigenen Körper mit dem für einen fremden Körper und in Studie 5 die Erkennung des eigenen Körpers und fremder Körper, sowie deren neuronale Korrelate, bei Frauen mit hohen und niedrigen Figur- und Gewichtssorgen verglichen. Methode: Für die Studien 1 bis 3 wurden weibliche und männliche Körper mittels einer Software erstellt und N = 104 Frauen ohne Essstörungen (Studie 1), n = 34 Frauen mit Anorexia nervosa und n = 31 Frauen mit Bulimia nervosa (Studie 2), sowie N = 93 Männern ohne Essstörungen (Studie 3) präsentiert. Die Probanden und Probandinnen sollten nach der Präsentation jedes Körperstimulus einordnen, wie sie sich gefühlt haben, und die Körper bewerten. Um die Identität der Körper zu manipulieren, wurden die Körper mit demselben Geschlecht der Versuchsperson sowohl mit dem Kopf einer fremden Person als auch mit dem Kopf der jeweiligen Versuchsperson präsentiert. In Studie 4 wurde ein bereits etabliertes EEG-Paradigma zur Untersuchung von Aufmerksamkeitsverzerrungen bei Körpern unterschiedlicher Identität und Gewichtsausprägungen angewendet. N = 20 Frauen mit hohen Figur- und Gewichtssorgen und n = 24 Frauen mit niedrigen Figur- und Gewichtssorgen wurden Bilder des eigenen Körpers der jeweiligen Probandin oder eines fremden Körpers präsentiert, während sie sich mit einer Detektionsaufgabe befassten. Durch die Messung eines Steady-State visuell evozierten Potentials (SSVEP) konnte abgeleitet werden, wie stark die einzelnen Körper von der Detektionsaufgabe ablenkten. In Studie 5 wurden n = 25 Frauen mit hohen Figur- und Gewichtssorgen und n = 26 Frauen mit niedrigen Figur- und Gewichtssorgen Morphfilme präsentiert, bei denen sich ein Körper allmählich in den eigenen Körper der jeweiligen Probandin oder einen fremden Körper verwandelte. Es wurde die Performanz in der Erkennung der Körper, sowie als neuronales Korrelat ein SSVEP miterhoben. Nach der SSVEP-Aufgabe wurden die einzelnen Morphs in einer weiteren Aufgabe ohne EEG präsentiert und die Erkennungsleistung erfasst. Ergebnisse: In Studie 1 zeigte sich, dass Frauen ohne Essstörungen keine körperübergreifenden Doppelstandards in der Körperbewertung aufwiesen, einen übergewichtigen Körper aber deutlich negativer bewerteten, wenn dieser die eigene Identität im Vergleich zu einer fremden Identität trug. In Studie 2 wurde erkenntlich, dass Frauen mit Anorexia nervosa und Frauen mit Bulimia nervosa mehr selbstschädigende Doppelstandards aufwiesen als Frauen ohne Essstörungen. Über alle Körpertypen hinweg bewerteten sie die Körper als dicker, wenn diese die eigene Identität im Vergleich zur fremden Identität trugen und unterschieden sich hierhin von Frauen ohne Essstörungen. Frauen mit Anorexia nervosa zeigten darüber hinaus signifikant deutlichere selbstschädigende Doppelstandards in den anderen Variablen als Frauen ohne Essstörungen. Studie 3 zeigte auf, dass Männer ohne Essstörungen unattraktive Körper negativer bewerteten, wenn sie die eigene Identität aufwiesen, und den idealen muskulösen Körper positiver bewerteten, wenn dieser die eigene Identität trug. In Studie 4 konnte darüber hinaus gezeigt werden, dass sich Frauen mit hohen Figur- und Gewichtssorgen stärker und andauernd durch Bilder ihres eigenen Körpers von einer Aufgabe ablenken ließen als durch Bilder fremder Körper. Dies traf auf Frauen mit niedrigen Figur- und Gewichtssorgen nicht zu. Studie 5 ergab, dass sich Frauen mit hohen und mit niedrigen Figur- und Gewichtssorgen generell nicht in der Erkennungsleistung und im SSVEP unterschieden. Allerdings brauchten Frauen mit hohen Figur- und Gewichtssorgen mehr Anteile des eigenen Körpers, um diesen in der Vermischung mit einem dünnen Körper zu erkennen. Diskussion: Die Ergebnisse verweisen auf die Aktivierung differentieller körperbezogener Schemata bei Körpern der eigenen Identität im Vergleich zu Körpern einer fremden Identität, die daher zu divergierenden Bewertungen dieser Körper führen. Dabei scheinen solche Doppelstandards in der Körperbewertung selbstschädigender zu sein, wenn eine Essstörungspathologie vorliegt. Außerdem können Männer im Gegensatz zu Frauen sich auch selbstdienlich bewerten, was zu den oftmals nachgewiesenen Geschlechtsunterschieden im Körperbild beitragen könnte. Darüber hinaus lassen sich Frauen mit hohen Figur- und Gewichtssorgen deutlicher durch ihren eigenen Körper als durch fremde Körper ablenken, was nahelegt, dass neben Körperbewertungen auch Aufmerksamkeitsverzerrungen von der Identität eines Körpers abhängig sind. Perzeptive Prozesse für die Differenzierung des eigenen Körpers von fremden Körpern erschienen gleichermaßen funktional bei Frauen mit hohen und niedrigen Figur- und Gewichtssorgen. Allerdings könnte auch hier der Einfluss dysfunktionaler körperbezogener Schemata zu einer schlechteren Erkennungsleistung bei Frauen mit hohen Figur- und Gewichtssorgen bei der Vermischung des eigenen Körpers mit einem dünnen Körper geführt haben. Insgesamt konnten mit dieser Dissertation einzelne Aspekte der kognitiv-behavioralen Theorie für Körperbildstörungen empirisch untermauert werden und es konnte gezeigt werden, dass kognitive Verzerrungen in der Körperverarbeitung von der Identität des Körpers und dem Ausmaß einer Körperbildstörung abhängig sind.

Le développement récent du transport ferroviaire a conduit à une forte augmentation du trafic durant la dernière décennie, augmentation qui devrait sepoursuivre dans la décennie à venir avec les futurs développements de ce mode de transport. L'augmentation du trafic se traduit pour l'infrastructure par une augmentation des sollicitations subies par les voies ferrées. La qualité des voies ferrées est garante de la performance du mode de transport ferroviaire,mais également de la sécurité des matériels roulants et des usagers de l'infrastructure. Conserver la qualité du réseau ferré est donc une priorité pour les gestionnaires d'infrastructures ferroviaires. Le ballast ferroviaire a pour rôle de répartir les efforts induits par la circulation des trains et d'assurer la bonne géométrie de l'infrastructure. La surveillance de la dégradation du ballast est donc primordiale pour assurer la qualité del'infrastructure.L'objectif de cette thèse est de proposer un outil numérique permettant d'anticiper la dégradation et le comportement d'une infrastructure ferroviaire sous trafic. Cet outil doit permettre de simuler efficacement lecomportement du ballast ferroviaire sous un grand nombre de cycles de chargements mobiles.Une première partie détaille la composition des infrastructures ferroviaires, précise les rôles du ballast et identifie les grandes lignes de son comportement.Il est fait le choix d'utiliser une méthode de représentation du ballast par élément fini et un modèle de comportement élastoplastique. Le ballast est alors traité comme un géomatériau continu répondant à des lois de comportementélastoplastique.Dans une seconde partie, les bases de la modélisation élastoplastique sont rappelées. Puis, plusieurs modèles de comportement issus de la littérature et comportant des éléments intéressants sont identifiés et étudiés.Dans une troisième partie, un nouveau modèle de comportement frottant compactant est proposé. Il est composé d’un critère nouveau et d'une loi d'écoulement originale. Enfin, le modèle est complété par la prise encompte, de la dégradation du matériau via une diminution de l'angle de frottement interne.Dans une quatrième partie, les méthodes stationnaires sont rappelées. Ces méthodes sont spécifiquement développées pour la modélisation des problèmes incluant des charges en mouvement. Les différents algorithmes sont implémentés àl'aide d'un code de calcul développé dans le logiciel Matlab et à l'aide du logiciel d'éléments finis COMSOL Multiphysics. En particulier, la méthode stationnaire à double échelle de temps, qui est un développement nouveau, permet la modélisation rapide d'un grand nombre de cycles de chargements et la prise en compte des effets d'usure du matériau.Dans une dernière partie, les deux principaux modèles tridimensionnels utilisés sont présentés. Sur un faible nombre de cycles de chargements, divers résultats sont établis selon les différents modèles de comportement utilisé. Sur un très grand nombre de cycles de chargements, les résultats obtenus montrent l'évolution des déformations irréversibles de la structure et de la dégradation du matériau. / Recent development in rail transportation has led traffic increasing during last decade, an increase which should continue in next decade due to the future developments of railway transport. Traffic growing induces infrastructure's solicitation increasing. Railways quality is warrant of rail transport performance, but also ensure security of the rolling stock and safety of the infrastructure users. Maintaining quality of the rail network is major priority for railway infrastructure managers. Purpose of rail ballast is to distribute load of the moving trains and to ensure track geometry. Monitoring of ballast degradation is therefore essential to ensure the quality of the infrastructure.The aim of this thesis is to develop a numerical tool to anticipate the degradation and behaviour of a railway infrastructure under traffic. This tool is intended to effectively simulate the behaviour of railway ballast under numerous mobile loads cycles.A first part details the composition of railway infrastructures, specifies roles of the ballast and identifies the main lines of its behaviour.Choice is made to use finite element method to represent the ballast and an elastic-plastic behaviour model. The ballast is then treated as a continuous geomaterial responding to elastic-plastic behaviour. Therefore, in a second part, the basics of elastic-plastic modelling are exposed. Then, several existing behaviours models which present interesting elements are identified and studied.In a third part, a new behaviour model, called "frottant-compactant" is presented. It is composed with a new criterion and an original flow rule. Finally, the model is completed by taking account of materials degradation via internal friction angle decreasing.In a fourth part, the steady-states methods are exposed. These methods are specifically developed for modelling problems including moving loads. Different algorithms are implemented using Matlab coding software and using the finites elements method software COMSOL Multiphysics. Principally, the double time-scale steady-state method, newly developed, allow rapid modelling of numerous loading cycles and representation of material wear effects.In a final part, the two three-dimensional models used are presented. On a few loading cycles, various results are established depending on different behaviour models. On a very large number of load cycles, the results obtained show the evolution of plastic strains in the structure and the degradation of the material.

Les convertisseurs électroniques de puissance sont voués à fonctionner sous des conditions applicatives de plus en plus sévères tout en respectant les impératifs d’efficacité énergétique et de fiabilité. Or, les besoins industriels tendent vers un plus haut niveau d’intégration fonctionnelle tout en améliorant le rapport qualité-prix. Dès lors, la solution utilisée pour le report des puces semi-conductrices est le siège de densités de courant importantes et d’un flux thermique élevé. La présence de défauts dans cette couche d’interconnexion peut conduire à la dégradation de ses performances et au vieillissement prématuré du composant. L’objectif de nos recherches est d’évaluer la pertinence d’une méthodologie basée sur la confrontation de simulations numériques et de campagnes expérimentales. L’objectif est d’améliorer la compréhension du comportement électrothermique en régime de conduction d’un transistor MOSFET en présence d’un void dans sa brasure. Dans cette manuscrite, nous présenterons la construction d’un modèle intégrant le couplage électrothermique de la partie active qui sera confronté à la réponse de résultats expérimentaux. Puis, une étude numérique basée sur la théorie des plans fractionnaires, qui minimise le nombre de simulations, sera exploitée afin de quantifier l’impact de la taille et de la position du défaut sur la réponse électrothermique du composant et de ses liaisons électriques. Les détails de la mise en place d’une étude expérimentale analogue permettront de mettre en perspective la complémentarité de cette approche. / Power converters nowadays are required to function under harsh conditions in meeting energy efficiency and reliability requirement. Whereas, industrial specifications tend toward a higher level of power integration in respect to the cost constraint. As a result, the die attach is one of the key elements in power module packaging because of high current densities and high heat flow which are transported through. Void formation in the die attach may lead to performance degradation and premature aging of the component. This study introduces a methodology based on the comparison of numerical simulations and experimental campaigns. The obtained results help to improve our understanding on the electro-thermal behaviour of MOSFETs with solder voids. In this thesis, we depict a finite element model in which electro-thermal coupling of a MOSFET active layer is taken in to account. Simulation results will be correlated to the experimental responses. Later on, a parametric numerical study based on the response surface method (RSM) which minimizes the number of simulations and future tests will be exploited to quantify the impact of void position and size on several selective performance criteria. A future serial experimental study in respect to the same RSM design is expected in prospect, in order to fulfil the complementarity for this approach.

No description available.

We consider two applications of control charts in health care. The first involves the comparison of four methods designed to detect an increase in the incidence rate of a rare health event, such as a congenital malformation. A number of methods have been proposed: among these are the Sets method, two modifications of the Sets method, and the CUSUM method based on the Poisson distribution. Many of the previously published comparisons of these methods used unrealistic assumptions or ignored implicit assumptions which led to misleading conclusions. We consider the situation where data are observed as a sequence of Bernoulli trials and propose the Bernoulli CUSUM chart as a desirable method for the surveillance of rare health events. We compare the steady-state average run length performance of the Sets methods and its modifications to the Bernoulli CUSUM chart under a wide variety of circumstances. Except in a very few instances we find that the Bernoulli CUSUM chart performs better than the Sets method and its modifications for the extensive number of cases considered. The second application area involves monitoring clinical outcomes, which requires accounting for the fact that each patient has a different risk of death prior to undergoing a health care procedure. We propose a risk-adjusted survival time CUSUM chart (RAST CUSUM) for monitoring clinical outcomes where the primary endpoint is a continuous, time-to-event variable that is right censored. Risk adjustment is accomplished using accelerated failure time regression models. We compare the average run length performance of the RAST CUSUM chart to the risk-adjusted Bernoulli CUSUM chart, using data from cardiac surgeries to motivate the details of the comparison. The comparisons show that the RAST CUSUM chart is more efficient at detecting deterioration in the quality of a clinical procedure than the risk-adjusted Bernoulli CUSUM chart, especially when the fraction of censored observations is not too high. We address details regarding the implementation of a prospective monitoring scheme using the RAST CUSUM chart. / Ph. D.