Thèses : « Effetto inversione »

1

ORLANDI, ANDREA. « ACTION REPRESENTATION IN THE HUMAN BRAIN : ELECTROPHYSIOLOGICAL MARKERS AND NEUROFUNCTIONAL CORRELATES ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2019. http://hdl.handle.net/10281/241203.

Texte intégral

Résumé :

La presente tesi si propone di studiare i decorsi temporali e correlati neurali legati al riconoscimento del corpo e alla codifica dell’azione utilizzando studi elettrofisiologici e di neuroimaging. È stato dimostrato come la capacità di riconoscimento di un corpo diminuisca se osservato capovolto indicando di una perturbazione dei processi di elaborazione configurazionale. Nella presente tesi è stata indagata la relazione tra riconoscimento del corpo, orientamento e attenzione, utilizzando immagini di posture corporee e strutture di cubi in orientamento canonico o capovolto. È stato ipotizzato un effetto dell’inversione sulla percezione dei corpi, ma non dei cubi. L’inversione del corpo ha portato ad una elaborazione dello stimolo più lenta (N2 anteriore più tardiva) e ad un aumento della selezione attentiva (Selection Negativity e P300 più ampie) necessaria per riconoscerlo e classificarlo. La ricostruzione della sorgente (swLORETA) ha confermato un maggior reclutamento di regioni attentive prefrontali. Per i cubi non è stata riscontrata una modulazione di tali componenti per via della mancanza di un orientamento naturale. I risultati hanno indicato come il riconoscimento del corpo sia dipendente dall’orientamento. Diversi studi hanno mostrato il coinvolgimento di regioni fronto-parieto-temporali durante l’osservazione di un’azione e l’effetto dell’expertise nel modulare l’attività di tali aree. In questo studio, lo sforzo muscolare è stato utilizzato come strumento per investigare l’effetto della pratica della danza sulla codifica dell’azione, ipotizzando una codifica maggiormente raffinata nei danzatori (vs. controlli). Gesti tecnici caratterizzati da sforzo lieve e intenso sono stati mostrati a danzatori e controlli durante un compito di immaginazione motoria. Nei danzatori sono stati riscontrati processi di elaborazione più rapidi (P2 posteriore precoce) e un coinvolgimento bilaterale della corteccia occipito-temporale (N2 posteriore e swLORETA). Gli esperti hanno anche mostrato un aumento della P300 anteriore e della Late Positivity (LP) parietale in risposta agli stimoli a sforzo intenso, indicando una codifica dell’azione più raffinata in virtù della conoscenza dei programmi motori. I controlli hanno mostrato una modulazione della LP occipitale dovuta ad un aumento dell’elaborazione delle informazioni cinematiche. La swLORETA ha indicato una maggiore attività nelle regioni visuomotorie nei danzatori, nelle regioni visive e prefrontali nei controlli. Durante il compito di immaginazione motoria è stata trovata una Anterior Negativity (AN) più ampia negli esperti. I movimenti a sforzo intenso hanno anche portato ad una AN più ampia nei controlli, mentre il risultato inverso è stato trovato nei danzatori. La swLORETA ha mostrato attività bilaterale nelle regioni visuomotorie e temporali nei danzatori e in regioni frontali superiori e mediali nei controlli. I risultati del secondo studio hanno suggerito una forte modulazione dei processi di rappresentazione dell’azione in base all’expertise acquisita e il contributo della corteccia occipito-temporale alla codifica dell’azione. L’ultimo studio ha esplorato i correlati neurali della rappresentazione di aspetti temporali dell’azione. I volontari hanno giudicato la piacevolezza estetica di sequenze di danza riprodotte con accelerazione uniforme o variata, indicando una preferenza per le variazioni temporali. È stato ipotizzato un maggiore coinvolgimento di regioni occipito-temporali e fronto-centrali in funzione dell’accelerazione crescente. Le sequenze variate hanno attivato regioni corticali e sottocorticali, tra cui la corteccia occipito-temporale, aree premotorie e motorie supplementari, lobulo parietale inferiore, giro frontale inferiore, insula, talamo e putamen. I risultati hanno suggerito un forte effetto di risonanza motoria durante l’elaborazione di aspetti cinematici legati alle variazioni temporali.
The present thesis aimed to investigate the time course and the neural substrates of body recognition and action representation using electrophysiological and neuroimaging studies. Previous evidence has shown that the presentation of a body in upside-down orientation resulted in decreased discrimination ability and increased N190 component, suggesting a disruption of configurational processing. In this thesis, the relationship between body recognition, orientation, and attention was assessed by presenting the participants with body postures and structures of cubes in either upright or inverted orientation. We predicted an effect of inversion on the perception of bodies but not cubes. The body inversion led to a slower stimulus processing (slower anterior N2) and enhanced attention allocation (larger Selection Negativity and P300) required to recognize and classify the target. Stronger recruitment of attention-related prefrontal regions was also found using swLORETA source reconstruction. No modulation of these components was shown for the cubes due to the lack of natural orientation. This first experiment provided evidence for an orientation-dependent recognition of the human body. Several studies have found the engagement of fronto-parieto-temporal regions in action perception, modulated as a function of expertise. Here, a dancer’s muscular effort was used as a tool to investigate the impact of ballet expertise on action representation. Compared to controls, a more refined and automatic effort encoding was expected in dancers due to their increased expertise with the repertoire of movement. Expert dancers and non-dancers were presented with effortful and effortless technical gestures and instructed to reproduce each of them mentally. A faster stimulus processing (faster posterior P2) and early bilateral engagement of the occipito-temporal cortex (OTC; posterior N2 and swLORETA) was found in dancers vs. controls during action observation. The experts also showed an increased anterior P300 and parietal Late Positivity (LP) in response to effortful than effortless steps. This was interpreted as an index of refined action coding due to their acquired motor knowledge. The non-experts only showed a modulation of the occipital LP likely due to enhanced processing of dance kinematics. The swLORETA indicated the recruitment of visuomotor regions in dancers, and visual and prefrontal areas in controls. During the motor imagery task a larger Anterior Negativity (AN) was found in experts compared to non-experts. Also, the effortful (vs. effortless) steps elicited a more negative AN in controls, while the opposite effect was found in ballet dancers. The swLORETA indicated bilateral recruitment of visuomotor and temporal areas in dancers and superior and medial frontal regions in controls. The evidence from the second study suggested a strong role of expertise in the modulation of the neural processes underlying action representation and an expertise-dependent contribution of the OTC to action coding during both observation and motor imagery. The final study of this thesis explored the neural correlates of action timing representation. The volunteers judged the aesthetical appraisal of videos depicting dance sequences reproduced with a uniform or varied acceleration, showing a preference for the varied version. Enhanced activity within OTC and fronto-central regions was expected as a function of increased acceleration changes. We found that the varied (vs. uniform) version of the sequences engaged a broader network of areas cortical and subcortical areas. The OTC, premotor and supplementary motor areas, inferior parietal lobule, inferior frontal gyrus, insula, thalamus, and putamen exhibited a crucial role in the representation of action timing. These results suggest a strong embodied response during the processing of dance kinematics as a function of time variation.

Styles APA, Harvard, Vancouver, ISO, etc.

2

Thomas, Lisa M. « Expertise and the inversion effect ». Thesis, University of Surrey, 2002. http://epubs.surrey.ac.uk/844088/.

Texte intégral

Résumé :

It has often been argued that the processing of faces is 'special' relative to the processing of other objects and there is much evidence in support of this notion. One source of evidence is the inversion effect, which occurs when faces presented upright are recognised significantly better than faces presented upside down. This effect of stimulus inversion has been shown to impair face recognition to a greater extent than for any other object class. It is this disproportionate effect that has been given as one source of evidence that face processing is special. However, other research has argued that effects of inversion can be found for non-face stimuli providing that there is sufficient development of expertise with them and that these stimuli can be defined by a common prototype. This thesis further explores this idea. Inversion effects were investigated for both prototypically and non-prototypically defined, abstract, chequerboard stimuli and compared with those for faces. When subjects learned to categorise chequerboard stimuli that were defined by a common prototype equal size inversion effects were found to those observed for faces. However, inversion effects were not observed for category training with multiple exemplars of chequerboard stimuli that were not defined by a common prototype. Together the findings are consistent with the idea that inversion effects are a general phenomenon resulting from the acquisition of category expertise with any prototype defined stimulus category. They undermine the inversion effect as a source of evidence for the specialness of face processing. Further, using a new Moving Windows technique, additional experiments investigated the underlying mechanisms responsible for the effects of inversion found for faces and chequerboards. These showed that the diagnostic image regions searched differ across the two stimulus classes. However, on the basis of the results, it is argued that the inversion effects found for both could result from impaired processing of second-order configural information.

Styles APA, Harvard, Vancouver, ISO, etc.

3

Seidshazileh, Kazem. « Effect of interfacial characteristics on phase inversion ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0029/NQ63484.pdf.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

4

Murali, Raghunath. « Scaling opportunities for bulk accumulation and inversion MOSFETs for gigascale integration ». Diss., Available online, Georgia Institute of Technology, 2004:, 2004. http://etd.gatech.edu/theses/submitted/etd-02132004-173432/unrestricted/murali%5FRaghunath%5F405%5F.pdf.

Texte intégral

Résumé :

Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2004.
Hess, Dennis, Committee Member; Meindl, James, Committee Chair; Allen, Phillip, Committee Member; Cressler, John, Committee Member; Davis, Jeffrey, Committee Member. Vita. Includes bibliographical references (leaves 108-119).

Styles APA, Harvard, Vancouver, ISO, etc.

5

Ouloin, Martyrs. « Méthode d’inversion d’un Modèle de diffusion Mobile Immobile fractionnaire ». Thesis, Avignon, 2012. http://www.theses.fr/2012AVIG0504/document.

Texte intégral

Résumé :

L’étude expérimentale du transport de soluté dans les milieux poreux montre des écarts à la loi de Fick. D’autre part, des progrès importants ont été accomplis sur le transport en milieu poreux, en supposant que les fluides (et les traceurs) en mouvement dans ces milieux sont arrêtés pendant des durées aléatoires. La matrice solide rend cette idée plausible. Nous étudions un modèle utilisant cette idée en l’associant à des durées d’immobilisation sans moyenne finie, en fait distribuées par des lois de Lévy. On arrive ainsi au modèle MIM fractionnaire, ou fractal.Ce modèle est une équation aux dérivées partielles pour la densité de traceur. Il équivaut à supposer que les particules de fluide et de traceur font des déplacements régis par un processus stochastique. Ce dernier est la limite hydrodynamique de marches au hasard fondées sur des déplacements convectifs, des sauts gaussiens, et des arrêts distribués suivant une loi de Lévy. Ces deux versions du même modèle donnent deux méthodes de simulation numérique.Nous montrons comment mettre en œuvre ces méthodes. Ceci a pour but la maîtrise d’outils de simulation, afin de comparer avec des données expérimentales pour savoir si ce modèle convient pour décrire le transport dans un milieu donné. Cette simulation, pour être efficace, nécessite la connaissance des paramètres du transport de soluté au sein du milieu donné. Ils sont difficilement mesurables et/ou identifiables en pratique. Donc, il faut pouvoir les estimer à partir de grandeurs qu’on sait mesurer directement, comme la densité d’un traceur. Pour cela, nous avons mis en place une méthode d’inversion qui permet d’extraire les paramètres du modèle MIM fractionnaire, à partir de données expérimentales. Cette méthode d’inversion est basée sur la transformation de Laplace. Elle utilise le lien entre les paramètres de transport du modèle MIM fractionnaire, et les dérivées de la transformée de Laplace des solutions de ce modèle. Ce lien est exact dans un milieu semi-infini, et seulement approché dans un milieu fini.Après avoir testé cette méthode en l’appliquant à des données numériques en essayant de retrouver leurs paramètres à "l’aveugle", nous l’appliquons à des données issues d’une expérience de traçage en milieu poreux insaturé
Appealing models for mass transport in porous media assume that fluid and tracer particles can be trapped during random periods. Among them, the fractional version of the Mobile Immobile Model (f-MIM) was found to agree with several tracer test data recorded in environmental media.This model is equivalent to a stochastic process whose density probability function satisfies an advection-diffusion equation equipped with a supplementary time derivative, of non-integer order. The stochastic process is the hydrodynamic limit of random walks accumulating convective displacements, diffusive displacements, and stagnation steps of random duration distributed by a stable Lévy law having no finite average. Random walk and fractional differential equation provide complementary simulation methods.We describe that methods, in view of having tools for comparing the model with tracer test data consisting of time concentration curves. An other essential step in this direction is finding the four parameters of the fractional equation which make its solutions fit at best given sets of such data. Hence, we also present an inversion method adapted to the f-MIM. This method is based on Laplace transform. It exploits the link between model's parameters and Laplace transformed solutions to f-MIM equation. The link is exact in semi-infinite domains. After having checked inverse method's efficiency for numerical artificial data, we apply it to real tracer test data recorded in non-saturated porous sand

Styles APA, Harvard, Vancouver, ISO, etc.

6

Civile, Ciro. « The face inversion effect and perceptual learning : features and configurations ». Thesis, University of Exeter, 2013. http://hdl.handle.net/10871/13564.

Texte intégral

Résumé :

This thesis explores the causes of the face inversion effect, which is a substantial decrement in performance in recognising facial stimuli when they are presented upside down (Yin,1969). I will provide results from both behavioural and electrophysiological (EEG) experiments to aid in the analysis of this effect. Over the course of six chapters I summarise my work during the four years of my PhD, and propose an explanation of the face inversion effect that is based on the general mechanisms for learning that we also share with other animals. In Chapter 1 I describe and discuss some of the main theories of face inversion. Chapter 2 used behavioural and EEG techniques to test one of the most popular explanations of the face inversion effect proposed by Diamond and Carey (1986). They proposed that it is the disruption of the expertise needed to exploit configural information that leads to the inversion effect. The experiments reported in Chapter 2 were published as in the Proceedings of the 34th annual conference of the Cognitive Science Society. In Chapter 3 I explore other potential causes of the inversion effect confirming that not only configural information is involved, but also single feature orientation information plays an important part in the inversion effect. All the experiments included in Chapter 3 are part of a paper accepted for publication in the Quarterly Journal of Experimental Psychology. Chapter 4 of this thesis went on to attempt to answer the question of whether configural information is really necessary to obtain an inversion effect. All the experiments presented in Chapter 4 are part of a manuscript in preparation for submission to the Quarterly Journal of Experimental Psychology. Chapter 5 includes some of the most innovative experiments from my PhD work. In particular it offers some behavioural and electrophysiological evidence that shows that it is possible to apply an associative approach to face inversion. Chapter 5 is a key component of this thesis because on the one hand it explains the face inversion effect using general mechanisms of perceptual learning (MKM model). On the other hand it also shows that there seems to be something extra needed to explain face recognition entirely. All the experiments included in Chapter 5 were reported in a paper submitted to the Journal of Experimental Psychology; Animal Behaviour Processes. Finally in Chapter 6 I summarise the implications that this work will have for explanations of the face inversion effect and some of the general processes involved in face perception.

Styles APA, Harvard, Vancouver, ISO, etc.

7

Hobiger, Manuel. « Polarisation des ondes de surface : caractérisation, inversion et application à l'étude de l'aléa sismique ». Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00577887.

Texte intégral

Résumé :

L'aléa sismique d'un site donné peut être largement influencé par des effets de site. Afin d'évaluer ces effets, la structure locale du sous-sol ainsi que les propriétés du champ d'onde doivent être étudiées. Les ondes de surface (ondes de Love et de Rayleigh) s'avèrent utiles, leurs propriétés (courbes de dispersion, ellipticité des ondes de Rayleigh) étant directement liées à la structure du sous-sol. Le paramètre clé pour l'identification du type d'onde est la polarisation. Dans la première partie de la thèse, de nouvelles méthodes pour l'estimation de paramètres de polarisation d'ondes de surface sont développées. Deux méthodes, DELFI et RayDec, estiment l'ellipticité des ondes de Rayleigh à partir d'enregistrements d'un seul capteur sismique. La troisième méthode, MUSIQUE, est basée sur la méthode MUSIC et utilise les enregistrements multi-composantes de réseaux sismiques afin de distinguer ondes de Love et ondes de Rayleigh et d'estimer leurs propriétés. Dans la deuxième partie de la thèse, une étude théorique de l'inversion de courbes d'ellipticité montre quelles parties de ces courbes véhiculent les informations importantes sur la structure du sol et comment l'inversion peut être améliorée. Le schéma d'inversion résultant est alors testé en l'appliquant à des données réelles mesurées pour 14 sites européens. Finalement, 22 séismes enregistrés par un réseau de capteurs dans la vallée de Santa Clara en Californie sont analysés par MUSIQUE. La répartition azimutale, les courbes de dispersion, la courbe d'ellipticité et les énergies des différents types d'ondes sont analysées et soulignent l'importance des ondes de surface diffractées dans le champ d'ondes enregistré.

Styles APA, Harvard, Vancouver, ISO, etc.

8

Ng, Chun Wai. « On the inversion and accumulation layer mobilities in N-channel trench DMOSFETS / ». View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?ELEC%202005%20NG.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

9

Brown, Andrew Paul. « Synthetic titanomagnetite : the effect of ball-milling, maghemitization and inversion ». Thesis, University of Newcastle Upon Tyne, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388658.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

10

Goodall, Harrison M. III. « The Effect of Inversion and Motor Expertise on Body Compatibility ». Scholarship @ Claremont, 2016. http://scholarship.claremont.edu/pomona_theses/159.

Texte intégral

Résumé :

Previous studies have established that when a subject’s attention is directed to a specific body part, the subject is able to move that body part faster than a body part their attention was not drawn to. This is known as the body compatibility effect, and it has been shown that this effect only occurs when viewing upright images of the human body. In this study, we presented control subjects and expert acrobats with inverted and upright stimuli. We hypothesized that the amount of time the acrobats spent inverted would result in the acrobats exhibiting body compatibility effects for both upright and inverted stimuli. Compatibility effects were observed in the upright condition for both groups, but neither group exhibited any compatibility effects in the inverted position. Unexpectedly the acrobats responded significantly faster to incongruent trials compared to the control subjects, leading to the conclusion that there must be some form of priming occurring concurrently with the body compatibility task allowing the acrobats to respond faster than the control participants.

Styles APA, Harvard, Vancouver, ISO, etc.

11

Newell, Robyn. « Are inversion, posture, motion and muscle effects important to spinal alignment ? » Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/46573.

Texte intégral

Résumé :

Rollover accidents are dynamic and complex events in which head contacts with the vehicle interior can cause catastrophic neck injuries through head-first impact. Ex vivo cadaver tests are valuable for studying these mechanisms of head-first axial loading neck injuries; however, they lack a biofidelic representation of neuromuscular control, postural stability, and overall spine posture. Computational modeling can be used to evaluate changes in the risk of neck injury under the influence of muscle forces, yet the exact muscles and levels of forces that are involved leading up to a head-first impact are unknown. Knowing the state of the neck prior to impact is critical to improving cadaveric and computational models of neck injury. Four human volunteer experiments were conducted to determine whether inversion, head position, muscle tensing, and dynamic motion influence the cervical spine alignment. These four studies included: (1) static inversion, (2) muscle tensing, (3) moment generation, (4) dynamic flexion/extension. For each experiment, cervical alignment was captured using fluoroscopy and muscle activity was captured using electromyography. The inverted posture and muscle activations were found to be different than the upright relaxed posture and the differences depend on the position of the head (study 1). Actively tensing the neck muscles in a free unconstrained task (study 2) and in generating flexion and extension forces with head constraint (study 3) resulted in different cervical alignment compared to the initial resting spine. Not only do these neck muscle contractions induce postural changes, they also provide a substantial stiffening effect to the neck. Finally, dynamically arriving at the neutral position did not result in the same cervical alignment as static neutral and the alignment depended on the direction that neutral is approached from (full flexion or full extension). These findings suggest that it may not be sufficient to replicate the upright resting posture in cadaveric and computational models of neck injury. Adopting in vivo postures and muscle activations, relevant to head-first impact, in the laboratory may help in replicating the spectrum of injuries observed in real life rollovers, an important step toward injury prevention.

Styles APA, Harvard, Vancouver, ISO, etc.

12

Jack, U. « Fabrication of wet phase inversion capillary membrane, dimension and diffusion effects ». Thesis, Cape Peninsula University of Technology, 2006. http://hdl.handle.net/20.500.11838/895.

Texte intégral

Résumé :

Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2006
A protocol already exists for fabrication of a capillary membrane having an internal ultrafiltration skin supported by a finger-like pore structure in the external capillary wall (Jacobs and Leukes, 1996; Jacobs and Sanderson, 1997). These membranes have been produced at the Institute of Polymer Science, University of Stellenbosch, South Africa. Two major applications emerged from the development of these internally skinned membranes. One application was in the production of potable water by Ultra-filtration (UF) from sources containing coloured water. A second application was in the immobilization of a white rot fungus in a ."gradostat" membrane bioreactor. Here a nutrient gradient through the membrane wall and fungal mat can be established and manipulated in order to stimulate continuous production of secondary metabolites (extra-cellular enzymes). These enzymes are useful in the degradation of polycyclic aromatic compounds, notably PCB species in contaminated water and soils (Jacobs and Sanderson, 1997). Two objectives emerged from experiences with the above applications. The first objective was to improve membrane performance in UF applications. In this case a reduction was sought in trans-membrane pressure differential required to attain a desired flux without sacrificing rejection. The pressure required for a given desired flux across a membrane depends on the resistance of the membrane skin layer and of its supporting sub-layer which together comprises the capillary wall and defmes its overall structure. If any of these resistances could be reduced, the overall resistance to transport of water would be reduced. Then it would be possible to operate the membrane at lower trans-membrane pressure differences. On the other hand, operation with higher pressure would also increase flux but require a thicker capillary wall to resist this pressure. In the attempt to optimise these properties of the capillary membrane, capillary membranes produced in the study reported here were tested to find the relationship of flux performance with the structures that resulted from varying key parameters affecting structure and integrity. The objective in the case of immobilizing fungi in membrane bioreactor applications was to attain thicker walls thus providing better support for the fungal mass. The internally skinned capillary membrane has finger-like microvoids that start next to the UF skin layer and extend across the capillary membrane wall and open at the external membrane periphery, giving an ideal structure for retaining the fungal biomass. The idea of a membrane with this type of morphology to immobilize white rot fungi was to anchor the growing fungus within these microvoids which imitate the natural environment in which these organisms live, that is, in the fibrous structure of decaying wood. The requirement to inoculate the microvoids with fungal spores (reproductive cells), implies that they need to be accessible from the outside, requiring a membrane wall that is externally unskinned. In the formation ofthe capillary membrane the processes of formation of the porous UP skin and the finger-like microvoids are mainly governed by diffusion of solvent out of a polymer dope (gel phase) and of non-solvent into the dope phase. Such exchanges are of primary importance between the bore fluid (containing non-solvent) and dope (containing solvent) or between the external spinning bath (high in solvent content) and dope. Diffusion effects also occur between the nascent pore voids and the precipitating polymer matrix. There are also expected to be some convection effects due to shear between the bore fluid and the moving dope gel phase and due to shrinkage ofthe gel phase. The variables selected for experimentation m the study reported here were: the dope extrusion rate (DER); dope composition (viscosity effects); bore fluid flow rate (BFF); bore fluid composition and wall thickness and diameter effects (determined largely by spinneret dimensions). Each of these has an expected effect on membrane structure and its resulting performance. Most were varied over narrow ranges indicated in the literature and by experience to be effective and critical. In addition, the effects of altering the walI thickness were investigated by using two different spinneret sizes. The external spinning bath composition (solvent content) was reported in the literature to be a particularly important parameter in the formation of externally unskinned membranes. Maintaining a high content of solvent in the external spinning bath could prevent skin formation. Too high a solvent content could, however, prevent phase transition and lead to later precipitation ofa dense skin on contact with the non-solvent in the later (humidification and rinsing) steps in the fmishing of the capillary membrane product. The external bath composition was therefore varied so as to find the bath composition that would match the cloud point for the polymer dope employed. As expected, the thickness of the membranes increased with DER increase. However, it was found that there is a critical wall thickness where an external skin layer is formed as a result of increasing the DER. A certain volumetric ratio ofDER to BFF (1,5:1 for this study) was therefore maintained in order to produce externally unskinned membranes. This shows that although the final membrane structure is detennined by the casting dope formulation, the fabrication protocol plays an equally important role in controlling structural properties and perfonnance. There was no significant change with the membrane thickness as a result of changing BFF but the voids became longer and more in number as the BFF was increased. Too high solvent content (99% NMP in this study) resulted in an external skin layer being formed. According to Smolders et.al. (1992), when the solvent content in the external spinning bath is too high, the polymer at the surface of the newly fonned membrane slowly dissolves in the external spinning bath re-forming a dope-like solution. When the newly formed membrane passes through the humidifier, the dope-like solution solidifies to form an external skin. At the same instance, too low solvent (93% for this study) resulted in external skin being fonned. Externally unskinned membranes were formed at 94 and 96% NMP bath composition. The use of a small spinneret resulted in very thin walled externally unskinned membranes.

Styles APA, Harvard, Vancouver, ISO, etc.

13

Wilson, Erin Lawall. « Effects of Fatigue & ; Gender on Peroneal Reflexes After Ankle Inversion ». Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/42445.

Texte intégral

Résumé :

An estimated 23,000 ankle injuries occur every day in the U.S. Ankle sprains account for 85% of all ankle injuries and inversion ankle sprains account for 85% of all ankle sprains. There is growing evidence that suggests gender and fatigue may increase the risk for inversion ankle sprains. Investigating the effects of fatigue and gender on peroneal reflex response after ankle inversion may help explain the differences in sprain rates with fatigue and gender. Therefore, the purpose of this study was to investigate the effects of fatigue and gender on peroneus brevis and peroneus longus reflexes after ankle inversion. A "trap-door" platform was used to elicit peroneal reflexes from sixteen males and fifteen females by suddenly inverting the ankle to 20°. Five unfatigued peroneal reflex measurements were performed before and after a fatigue protocol that attempted to fatigue the ankle evertors over 12 minutes to 75% of the unfatigued MVC torque. Results showed that reflex delay was not affected by fatigue, gender, or their interaction. PL reflex amplitude was not affected by fatigue or gender but was affected by their interaction. Results showed that PL reflex amplitude decreased by 11.3% in males and increased 22.1% in females with fatigue. A secondary analysis attempted to rule out extraneous factors that could have contributed to the differences in reflex response, but no experimental explanations were found. The differences in PL reflex amplitude were attributed to biomechanical, physiological, and anatomical differences between males and females.
Master of Science

Styles APA, Harvard, Vancouver, ISO, etc.

14

Tenev, Tihomir Genchev. « Modeling of electroluminescence in InSb quantum wells and inversion asymmetric effects ». Thesis, Lancaster University, 2010. http://eprints.lancs.ac.uk/54013/.

Texte intégral

Résumé :

The main focus of the dissertation is description, modeling and understanding of the mechanisms underpinning electroluminescence from quantum wells. The dissertation contains original contribution of methodological and phenomenological character. We have described in detail the eight band model within the envelope function approximation(EFA) using the Löwd in perturbation method used for band structure calculations. Although not novel, a detailed derivation of this is rarely done in the literature. We have derived a theoretical expression for electroluminescence spectral emittance based entirely on quantum mechanical model, unlike the more usual semi classical models used in semiconductor physics. The final expression for the spectral emittance has a different dependence compared to the semi classical expression, namely the prefactor in the newly derived expression is proportional to 2 . We use the combination of 8 band EFA method and the newly derived expression for spectral emittance to interpret experimental measurements on unpolarized spectral emittance from several InSb/AlxIn1-xSbquantum wells. We do that using slightly novel procedure and identify several transitions unreported in InSb/AlxIn1-xSb material system up to now. In simplified models these are regarded as forbidden. We show that in 8 band EFA model there aren’t any forbidden transitions. Instead all transitions are allowed and we discuss the product of momentum matrix elements and 2D density of states, to which we refer as "generalized selection rule", as the quantity which determines the strength of the individual transitions in different energy ranges. Furthermore we discuss three groups of mechanisms which determine various properties of the electroluminescence spectrum. These groups are entirely general to electroluminescence from all sorts of quantum wells. They are: (i) band structure embodied in the "generalized selection rules" ; (2) broadening effects and (3) statistical effects. Very important are the effects of structure inversion asymmetry (SIA) on the "generalized selection rules" and the spectral emittance, which we describe and explain. Finally we discuss aspects of two other major themes related to the two characteristic properties of InSb:(i) the broken space inversion invariance and (ii) the relativistic correction of spin-orbit coupling.

Styles APA, Harvard, Vancouver, ISO, etc.

15

Zhou, Wei. « Velocity model building by full waveform inversion of early arrivals & ; reflections and case study with gas cloud effect ». Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAU024/document.

Texte intégral

Résumé :

L'inversion des formes d'onde (full waveform inversion, FWI) a suscité un intérêt dans le monde entier pour sa capacité à estimer de manière précise et détaillée les propriétés physiques du sous-sol. La FWI est généralement formulée sous la forme d'un problème d'ajustement des données par moindres carrés et résolus par une approche linéarisée utilisant des méthodes d'optimisation locales. Cependant, la FWI est bien connue de souffrir du problème de saut de phase rendant les résultats fortement dépendant de la qualité des modèles initiaux. L'inversion des formes d'ondes des arrivées réfléchies (reflection waveform inversion, RWI) a récemment été proposée pour atténuer ce problème en supposant une séparation d'échelle entre le modèle de vitesse lisse et le modèle de réflectivité à haut nombre d'onde. La formulation de RWI considère explicitement les ondes réfléchies afin d'extraire de ces ondes une information sur les variations lisses de vitesse des zones profondes. Cependant, la méthode néglige les ondes transmises qui contraignant les informations lisses de vitesse en proche surface.Dans cette thèse, une étude de la sensibilité en nombre d'ondes des méthodes de FWI et RWI a d'abord été revisitée dans le cadre de la tomographie en diffraction et des décompositions orthogonales. A partir de cette analyse, je propose une nouvelle méthode, à savoir l'inversion jointe des formes d'ondes transmises et réfléchies (joint full waveform inversion, JFWI). La méthode propose une formulation unifiée pour combiner la FWI des transmissions et la RWI pour les réflexions, donnant naturellement une sensibilité commune aux petits nombres d'onde venant des arrivées grand-angle et réfléchies. Les composantes à hauts nombres d'onde sont naturellement atténuées par la formulation. Pour satisfaire l'hypothèse de séparation d'échelle, j'utilise une paramétrisation du sous-sol basée sur la vitesse des ondes de compression et l'impédance acoustique. La complexité temporelle de cette approche est le double de la méthode de FWI classique et la requête mémoire reste la même.Une procédure d'inversion est ensuite proposée, permettant d'estimer alternativement le modèle de la vitesse du sous-sol par JFWI et l'impédance inversion de formes d'ondes réfléchies. Un exemple synthétique réaliste du modèle de Valhall est d'abord utilisé avec des données de streamer et à partir d'un modèle initial très lisse. Dans ce cadre, alors que la FWI converge vers un minimum local, la JFWI réussit à reconstruire un modèle de vitesse lisse de bonne qualité. La prise en compte des ondes tournante par la JFWI montre un fort intérêt pour la qualité de reconstruction superficielle, comparée à la méthode RWI seule. Cela se traduit ensuite par une reconstruction améliorée en profondeur. Le modèle de vitesse lisse construit par JFWI peut ensuite être considéré comme modèle initial pour la FWI classique, afin d'injecter le contenu en haut nombres d'onde tout en évitant le problème de saut de phase.Les avantages et limites de l'approche de JFWI sont ensuite étudiés dans une application sur données réelles, venant d'un profil 2D de données de fond de mer (OBC) recoupant un nuage de gaz au dessus d'un réservoir. Plusieurs modèles initiaux et stratégies d'inversion sont testés afin de minimiser le problème de saut de phase, tout en construisant des modèles de sous-sol avec une résolution suffisante. Sous réserve de mettre en œuvre des stratégies limitant le problème de saut de phase, la JFWI montre qu'elle peut produire un modèle de vitesse acceptable, injectant les bas nombres d'onde dans le modèle de vitesse. L'amélioration de l'éclairage en angles de diffraction fournie par des acquisitions 3D devrait permettre de pouvoir commencer l'inversion par JFWI à partir de modèle encore moins bien définis
Full waveform inversion (FWI) has attracted worldwide interest for its capacity to estimate the physical properties of the subsurface in details. It is often formulated as a least-squares data-fitting procedure and routinely solved by linearized optimization methods. However, FWI is well known to suffer from cycle skipping problem making the final estimations strongly depend on the user-defined initial models. Reflection waveform inversion (RWI) is recently proposed to mitigate such cycle skipping problem by assuming a scale separation between the background velocity and high-wavenumber reflectivity. It explicitly considers reflected waves such that large-wavelength variations of deep zones can be extracted at the early stage of inversion. Yet, the large-wavelength information of the near surface carried by transmitted waves is neglected.In this thesis, the sensitivity of FWI and RWI to subsurface wavenumbers is revisited in the frame of diffraction tomography and orthogonal decompositions. Based on this analysis, I propose a new method, namely joint full waveform inversion (JFWI), which combines the transmission-oriented FWI and RWI in a unified formulation for a joint sensitivity to low wavenumbers from wide-angle arrivals and short-spread reflections. High-wavenumber components are naturally attenuated during the computation of model updates. To meet the scale separation assumption, I also use a subsurface parameterization based on compressional velocity and acoustic impedance. The temporal complexity of this approach is twice of FWI and the memory requirement is the same.An integrated workflow is then proposed to build the subsurface velocity and impedance models in an alternate way by JFWI and waveform inversion of the reflection data, respectively. In the synthetic example, JFWI is applied to a streamer seismic data set computed in the synthetic Valhall model, the large-wavelength characteristics of which are missing in the initial 1D model. While FWI converges to a local minimum, JFWI succeeds in building a reliable velocity macromodel. Compared with RWI, the involvement of diving waves in JFWI improves the reconstruction of shallow velocities, which translates into an improved imaging at greater depths. The smooth velocity model built by JFWI can be subsequently taken as the initial model for conventional FWI to inject high-wavenumber content without obvious cycle skipping problems.The main promises and limitations of the approach are also reviewed in the real-data application on the 2D OBC profile cross-cutting gas cloud.Several initial models and offset-driven strategies are tested with the aim to manage cycle skipping while building subsurface models with sufficient resolution. JFWI can produce an acceptable velocity model provided that the cycle skipping problem is mitigated and sufficient low-wavenumber content is recovered at the early stage of inversion. Improved scattering-angle illumination provided by 3D acquisitions would allow me to start from cruder initial models

Styles APA, Harvard, Vancouver, ISO, etc.

16

Liu, Lixian. « The effect of order of inversion on SAGE II profile retrieval ». Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/25866.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

17

Psalta, Lilia. « The effect of image inversion on the perception of facial expression ». Thesis, University of York, 2014. http://etheses.whiterose.ac.uk/8209/.

Texte intégral

Résumé :

The Thatcher illusion provides a compelling example of the cost of face inversion. When the eyes and the mouth are turned upside-down relative to the rest of the face - a transform now known in the research literature as 'thatcherization' - the facial expression appears grotesque. This distortion of the face is immediately perceived when the face is upright. However, when the image is inverted the grotesque appearance is no longer visible. The aim of this thesis was to explore the behavioural and neural basis of this compelling illusion. This thesis provides a significant contribution to our understanding of the Thatcher Illusion using a combination of neuroimaging and behavioural results. The key findings of this thesis are that the neural basis of the Thatcher illusion is founded on the orientation-sensitivity of face-selective regions which are involved in the processing of facial expression. Behavioural findings suggest that the perception of the Thatcher illusion is still evident in the absence of configural information. Our findings demonstrated that a key component of the Thatcher illusion is to be found in orientation-specific encoding of the expressive features (eyes and mouth) of the face. This challenges previous interpretations of the Thatcher illusion that are based on a disruption of configural processing. Further results suggest that the effect of inversion found in the Thatcher illusion is not specific to grotesque expressions, but reflects a more general orientation-specific encoding of expressive features. Finally, the selectivity of the Thatcher illusion to the processing of expression is shown by the lack of effect of thatcherization on the processing of facial identity. These results provide further support for the idea that different processes underlie the perception of identity and expression.

Styles APA, Harvard, Vancouver, ISO, etc.

18

Huynh, Carol. « The Body Inversion Effect : The Role of Visual Appearance on Body Processing ». Thesis, North Dakota State University, 2015. https://hdl.handle.net/10365/27864.

Texte intégral

Résumé :

The purpose of this study was to determine if body stimuli are uniquely processed by the visual recognition system. First, my results supported past findings showing that body processing differs from object processing (e.g., cars, chairs, houses). However, body processing depended on the presence/absence of a head. Second, the nature of appearance impacted observers’ performance such that discrimination was better for real than artificial bodies. Finally, I examined the impact of body appearance on event-related potential (ERP) responses, specifically the P100 and N170, and found that amplitudes elicited by real headless bodies was significantly larger than amplitudes elicited by all other variations in body appearance. In general, these results suggest the existence of a body recognition system that processes body images varying in visual appearance. However, this system may be more tuned to bodies that most resemble natural appearance and less tuned to bodies that deviate away from it.

Styles APA, Harvard, Vancouver, ISO, etc.

19

Viala, Christophe Asch Mark. « Inversion géoacoustique temps réel de signaux large bande par grands fonds ». [S.l.] : [s.n.], 2007. http://tel.archives-ouvertes.fr/tel-00258272/fr.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

20

Ray, Thomas J. « The acute metabolic and hemodynamic effects of body inversion during rest and exercise ». Thesis, Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/53158.

Texte intégral

Résumé :

Suspension of the body in the head-down posture (90° below the horizontal) for traction and added resistance to exercise has generated considerable interest in recent years. However, recent investigators of inversion have cautioned individuals not to participate in such activities until further research could be performed on the effects of exercise in the head-down position. The purpose of this investigation was to examine the acute metabolic and hemodynamic responses of men at rest and during exercise in the inverted posture (90° head-down tilt) versus the supine and standing postures. The parameters investigated were oxygen consumption(V̇O₂), heart rate(HR), systolic blood pressure (SBP), and diastolic blood pressure(DBP). Eleven male recreational athletes underwent 6 sessions of postural change. The baseline posture was sitting and the critical positions were supine, standing, and inverted. The subjects were asked to remain in each of these postures for three minutes. In the first 2 sessions, oxygen consumption(V̇O₂), was measured at rest and during 45° hip-f1exion respectively, The V̇O₂ in the inverted posture at rest was found to be 1.7% greater than the V̇O₂ in the standing and the supine postures. V̇O₂ in the inverted posture during exercise was 7% and 36.5% greater than in the supine and standing postures, respective1y. A statistical significance in HR at rest in the standing posture versus the inverted and supine postures was observed. During 45° hip-flexion activity, the HR in the standing posture was found to be significantly faster than the supine posture. The HR in the inverted posture was significantly faster than the supine posture as well. At rest, there was no significant increase in SBP as re1ated to posture. During exercise, the SBP was significant1y greater; at rest in each of the postures. Both postural and exercise factors significantly affected the DBP. The post-hoc analyses showed supine resting DBP was significantly lower than in the other two resting postures. During exercise, the standing BP was significantly greater than the supine and inverted DBP. These data demonstrate: A) V̇O₂ in the supine and inverted postures is significantly greater than in the standing postures. B) a statistically significant increase in HR occurs in the standing posture as compared to the supine and inverted postures; however, it does not appear to be clinically significant, C) with the arms maintained in the anatomical position for all postural changes, the SBP was not significantly affected by the change of posture, but was significantly increased with exercise. D) and DBP in the standing posture was statistically greater than in the other two postures and DBP in the inverted posture was significantly elevated above that found in the supine posture.
Master of Science

Styles APA, Harvard, Vancouver, ISO, etc.

21

Bassom, A. P. « An inversion method for the geomagnetic induction problem and the stability of some fluid flows at high Reynolds numbers ». Thesis, University of Exeter, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379471.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

22

Tan, Eugene. « Design, fabrication and characterization of N-channel InGaAsP-InP based inversion channel technology devices (ICT) for optoelectronic integrated circuits (OEIC), double heterojunction optoelectronic switches (DOES), heterojunction field-effect transistors (HFET), bipolar inversion channel field-effect transistors (BICFET) and bipolar inversion channel phototransistors (BICPT) ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0006/NQ42767.pdf.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

23

Benachir, Mohcine. « Simulation numérique et modélisation des transistors MOS sur silicium sur isolant à inversion volumique ». Grenoble INPG, 1989. http://www.theses.fr/1989INPG0090.

Texte intégral

Résumé :

Dans la premiere partie de la these, nous presentons un nouveau mode de fonctionnement des transistors mos sur silicium sur isolant, qui consiste dans l'inversion forte et totale du film de silicium. Nous presentons ensuite les avantages induits par ce nouveau mode de fonctionnement. Nous montrons aussi qu'il est possible d'etablir, dans les deux cas extremes de transistors a film de silicium respectivement tres mince et tres epais, des modeles analytiques simples qui decrivent adequatement le fonctionnement electrique des tmos a volume inverse (tmos-vi) en regime ohmique. La deuxieme partie est consacree a la presentation des diverses techniques numeriques et equations physiques que nous avons retenues pour la realisation du simulateur electrique bidimensionnel des structures tmos-ssi: isis ii. L'objet de la troisieme partie est d'illustrer les possibilites d'etudes par la simulation electrique des dispositifs ssi, offertes par isis ii

Styles APA, Harvard, Vancouver, ISO, etc.

24

Sawkins, Kate. « The Placebo Effect of Ankle Taping on Ankle Instability ». Thesis, Physiotherapy, 2007. http://hdl.handle.net/2123/3574.

Texte intégral

Résumé :

Purpose: Recurrence of ankle sprains is common among athletes. While ankle taping reduces the risk of injury, the mechanism underlying its effectiveness remains unclear. Anecdotal reports suggest a role for the athlete’s belief that taping will protect them from injury. That is, taping may have a placebo effect. The purpose of the present study was to determine whether there was a placebo effect with ankle taping in individuals with ankle instability. Methods: 30 participants with ankle instability completed a single-limb hopping test and a modified star excursion balance test under three conditions: 1) real tape, 2) placebo tape, and 3) control (no tape). Participants were blinded to the purpose of the study and were informed that the study aimed to compare two methods of ankle taping referred to as “mechanical” (real) and “proprioceptive” (placebo). The order of testing the three conditions and the two functional tests was randomised. Results: There was no significant difference in performance among the three conditions for the single-limb hopping test (p=0.865) or the modified star excursion balance test (p=0.491). A secondary exploratory analysis, however, revealed that real and placebo ankle taping influenced participants’ perceptions of stability, confidence and reassurance when performing the functional tests. Conclusion: The role of the placebo effect with ankle taping in individuals with ankle instability remains unclear. Clinicians, therefore, should continue to use ankle taping techniques of known efficacy. They should, however, focus on maximising patients’ belief in the efficacy of ankle taping, since its application reassured participants and improved perceived stability and confidence. The effect of ankle taping on participants’ perceptions may contribute to its effectiveness in preventing injury. This proposal requires further investigation.

Styles APA, Harvard, Vancouver, ISO, etc.

25

Shen, Lin. « THE EFFECT OF HOT CARRIER STRESS ON LOW NOISE AMPLIFIER RADIO FREQUENCY PERFORMANCE UNDER WEAK AND STRONG INVERSION ». Master's thesis, University of Central Florida, 2006. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2235.

Texte intégral

Résumé :

This thesis work is mainly focused on studying RF performance degradation of a low noise amplifier (LNA) circuit due to hot carrier effect (HCE) in both the weak and strong inversion regions. Since the figures of merit for the RF circuit characterization are gain, noise figure, input, and output matching, the LNA RF performance drift is evaluated in a Cadence SpectreRF simulator subject to these features. This thesis presents hot carrier induced degradation results of an LNA to show that the HCE phenomenon is one of the serious reliability issues in the aggressively scaled RF CMOS design, especially for long-term operation of these devices. The predicted degradation from simulation results can be used design reliable CMOS RF circuits.
M.S.
Department of Electrical and Computer Engineering
Engineering and Computer Science
Electrical Engineering

Styles APA, Harvard, Vancouver, ISO, etc.

26

Kyrk, Tibuzzi Sofia. « Effect of exercise therapy on eversion/inversion angle in female runners : : A pilot study ». Thesis, Linnéuniversitetet, Institutionen för idrottsvetenskap (ID), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-68594.

Texte intégral

Résumé :

Background: Running has many health benefits and has therefore become a sport with an expanded popularity worldwide. With it comes an increased incidence of overuse injuries, and there is a constant debate whether the shoes a runner uses should be as supportive as possible or minimalistic in order to facilitate a more natural running pattern. Many running retail outlets use video analysis to find out whether the runner has excessive rearfoot eversion (if they overpronate) or not and prescribe running shoes accordingly. Purpose: The purpose of the present study was to investigate the effect of an exercise program on pronation/rearfoot eversion in female recreational runners and compare the results to running with a shoe with support under the midsole, a stability shoe. Method: Eight participants were recruited, and they were all recreational female endurance runners. On test day 1 a maximum voluntary isometric contraction (MVIC) of the ankle invertors was recorded. After that, the rearfoot inversion/ eversion angle was measured whilst running on a treadmill both in neutral and in stability shoes. The participants were divided in two groups using the every other method, and the intervention group (5 participants) went home with an exercise program to carry out over 6-8 weeks, and the control group (3 participants) did not. On test day 2 the same procedure followed. Due to the small sample size the current study is categorised as a pilot study. Results: There was no significant difference (p>0.05) in maximum voluntary isometric contraction between the two test days, in both groups, and also no significant difference (p>0.05) in rearfoot eversion in either of the groups and not when comparing the different types of shoes. Looking at individual results in the study group however there is an indication that rearfoot eversion decreased for more participants than did not, and it would therefore be of interest to look at this topic on a larger group. Conclusion: The results showed no significant difference in rearfoot eversion/ inversion after exercise therapy, however after analysing individual results it would be of interest to see this pilot study on a larger group.
Bakgrund: Löpning har många hälsofördelar och har därför blivit en sport med ökad popularitet över hela världen. Med det kommer en ökad förekomst av skador och det finns en ständig debatt om de skor som en löpare använder ska vara så uppbyggda som möjligt eller mer minimalistiska för att främja ett mer naturligt löpsteg. Många löparbutiker använder videoanalys för att ta reda på om löparen har en överdriven eversion i subtalarleden (om de hyperpronerar) eller inte och rekommenderar löparskor i enlighet med detta. Syfte: Syftet med den aktuella studien var att utreda effekten av ett träningsprogram på pronation/subtalar eversion hos kvinnliga distanslöpare, och att jämföra resultatet med en löparsko med extra stöd under fotvalvet. Metod: Åtta deltagare rekryterades till studien, och de var alla kvinnliga motionslöpare. På testdag 1 registrerades en maximal isometrisk kontraktion av fotledens invertorer. Därefter mättes vinkeln av inversion/eversion under löpning på en löpband både i neutrala och i stabilitetsskor. Deltagarna delades in i två grupper med hjälp av varannan-metoden och interventionsgruppen (5 deltagare) gick hem med ett träningsprogram att utföra över 6-8 veckor, och kontrollgruppen (3 deltagare) gjorde inget. På testdag 2 följde samma procedur. På grund av den lilla gruppstorleken kategoriseras den aktuella studien som en pilotstudie. Resultat: Det var ingen signifikant skillnad (p> 0.05) av på den maximala isometriska kontraktionen mellan de två testdagarna, i någon av grupperna, och ingen signifikant skillnad (p> 0.05) av inversion/eversion i någon av grupperna och inte heller när man jämförde de olika typerna av skor. Om man tittar på individuella resultat i studiegruppen finns det dock en indikation på att nivån av eversion minskade för fler deltagare än inte, och det skulle därför vara intressant att titta på detta ämnet i en större grupp. Konklusion: Resultaten visade inte någon signifikant skillnad i eversion/inversion i subtalarleden efter träningsterapi, men efter analysering av individuella resultat skulle det vara intressant att se denna pilotstudie i större grupp.

Styles APA, Harvard, Vancouver, ISO, etc.

27

Cronin, Alison. « Effect of selected ankle supports on resistance to inversion force and range of motion ». Thesis, University of Ottawa (Canada), 2001. http://hdl.handle.net/10393/9120.

Texte intégral

Résumé :

The purpose of this study was to determine if the ankle supports chosen were able to provide increased resistance to inversion, as measured by moment of force, without limiting plantar flexion or dorsiflexion. Resistance to inversion moment of force was measured on an isokinetic dynamometer (KinCom) in passive mode, for six support conditions (low-top (LT) and midcut (MC) shoes with semi-rigid and flexible orthoses). The braces used were the Active Ankle T1 Trainer (AA) and the Ankle Stabilizing Orthosis (ASO). The shoes were ASICS Gel Airier volleyball shoes in low-top and midcut models. It was found that there was a significant difference in resistance to inversion moment of force mean, between the MC alone and the LT with AA. It was concluded that the best support condition was the combination of LT and AA. It decreased sagittal range of motion the least and provided increased force to resist inversion as compared to the control condition (LT). (Abstract shortened by UMI.)

Styles APA, Harvard, Vancouver, ISO, etc.

28

Chen, Zhengxiao. « Microwave remote sensing of vegetation : Stochastic Lindenmayer systems, collective scattering effects, and neural network inversions / ». Thesis, Connect to this title online ; UW restricted, 1994. http://hdl.handle.net/1773/5854.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

29

Hardarson, Gisli. « The Effects of Using Results from Inversion by Evolutionary Algorithms to Retrain Artificial Neural Networks ». Thesis, University of Skövde, Department of Computer Science, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-411.

Texte intégral

Résumé :

The aim of inverting artificial neural networks (ANNs) is to find input patterns that are strongly classified as a predefined class. In this project an ANN is inverted by an evolutionary algorithm. The network is retrained by using the patterns extracted by the inversion as counter-examples, i.e. to classify the patterns as belonging to no class, which is the opposite of what the network previously did. The hypothesis is that the counter-examples extracted by the inversion will cause larger updates of the weights of the ANN and create a better mapping than what is caused by retraining using randomly generated counter-examples. This hypothesis is tested on recognition of pictures of handwritten digits. The tests indicate that this hypothesis is correct. However, the test- and training errors are higher when retraining using counter-examples, than for training only on examples of clean digits. It can be concluded that the counter-examples generated by the inversion have a great impact on the network. It is still unclear whether the quality of the network can be improved using this method.

Styles APA, Harvard, Vancouver, ISO, etc.

30

Wolters, Ulrike [Verfasser]. « Inversion Dependent Losses in Yb:YAG and their Effects on Thin-Disk Laser Operation / Ulrike Wolters ». Aachen : Shaker, 2014. http://d-nb.info/1053903987/34.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

31

Zlotowski, Jakub Aleksander. « Understanding Anthropomorphism in the Interaction Between Users and Robots ». Thesis, University of Canterbury. HIT Lab NZ, 2015. http://hdl.handle.net/10092/11259.

Texte intégral

Résumé :

Anthropomorphism is a common phenomenon when people attribute human characteristics to non-human objects. It plays an important role in acceptance of robots in natural human environments. Various studies in the field of Human-Robot Interaction (HRI) show that there are various factors that can affect the extent to which a robot is anthropomorphized. However, our knowledge of this phenomenon is segmented, as there is a lack of a coherent model of anthropomorphism that could consistently explain these findings. A robot should be able to adjust its level of anthropomorphism to a level that can optimize its task performance. In order to do that, robotic system designers must know which characteristics affect the perception of robots' anthropomorphism. Currently, existing models of anthropomorphism emphasize the importance of the context and perceiver in this phenomenon, but provide little guidelines regarding the factors of a perceived object that are affecting it. The proposed reverse process to anthropomorphization is known as dehumanization. In the recent years research in social psychology has found which characteristics are deprived from people who are perceived as subhumans or are objectified. Furthermore, the process of dehumanization is two dimensional rather than unidimensional. This thesis discusses a model of anthropomorphism that uses characteristics from both dimensions of dehumanization and those relating to robots' physical appearance to affect the anthropomorphism of a robot. Furthermore, involvement of implicit and explicit processes in anthropomorphization are discussed. In this thesis I present five empirical studies that were conducted to explore anthropomorphism in HRI. Chapter 3 discusses development and validation of a cognitive measurement of humanlikeness using the magnitude of the inversion effect. Although robot stimuli were processed more similarly to human stimuli rather than objects and induced the inversion effect, the results suggest that this measure has limited potential for measuring humanlikeness due to the low variance that it can explain. The second experiment, presented in Chapter 4 explored the involvement of Type I and Type II processing in anthropomorphism. The main findings of this study suggest that anthropomorphism is not a result of a dual-process and self-reports have a potential to be suitable measurement tools of anthropomorphism. Chapter 5 presents the first empirical work on the dimensionality of anthropomorphism. Only perceived emotionality of a robot, but not its perceived intelligence, affects its anthropomorphization. This finding is further supported by a follow up experiment, presented in Chapter 6, that shows that Human Uniqueness dimension is less relevant for a robot's anthropomorphiazability than Human Nature (HN) dimension. Intentionality of a robot did not result in its higher anthropomorphizability. Furthermore, this experiment showed that humanlike appearance of a robot is not linearly related with its anthropomorphism during HRI. The lack of linear relationship between humanlike appearance and attribution of HN traits to a robot during HRI is further supported by the study described in Chapter 7. This last experiment shows also that another factor of HN, sociability, affects the extent to which a robot is anthropomorphized and therefore the relevance of HN dimension in the process of anthropomorphization. This thesis elaborates on the process of anthropomorphism as an important factor affecting HRI. Without fully understanding the process itself and what factors make robots to be anthropomorphized it is hard to measure the impact of anthropomorphism on HRI. It is hoped that understanding anthropomorphism in HRI will make it possible to design interactions in a way that optimizes the benefits of that phenomenon for an interaction.

Styles APA, Harvard, Vancouver, ISO, etc.

32

Watterson, Todd L. « Effects of Cache Valley Particulate Matter on Human Lung Cells ». DigitalCommons@USU, 2012. https://digitalcommons.usu.edu/etd/1341.

Texte intégral

Résumé :

During wintertime temperature inversion episodes the concentrations of particulate air pollution, also defined as particulate matter (PM), in Utah’s Cache Valley have often been highest in the nation, with concentrations surpassing more populated and industrial areas. This has attracted much local and national attention to the area and its pollution. The Cache Valley has recently been declared to be in non-attainment of provisions of Federal law bringing to bear Federal regulatory attention as well. While there is epidemiological evidence indicating that PM is detrimental to public health, there is much less information indicating by which biological and molecular mechanisms PM can exert harm. This study was undertaken to better understand the mechanisms by which ambient PM collected in the Cache Valley can be harmful to human lung cells. Cache Valley PM was found to be mildly cytotoxic only at concentrations that were much greater than physiologically achievable, and such concentrations were difficult to obtain with the limited amounts of captured ambient PM. The limited cytotoxicity was despite apparent PM-induced pro-apoptotic signaling such as caspase-3 upregulation, and activation of caspase-12 and calpain. Cache Valley PM was found to be stressful to cells, triggering endoplasmic reticulum stress and the unfolded protein response. Cache Valley PM was also found to be inflammogenic leading to activation of pro-inflammatory transcription factors, increases in the release of pro-inflammatory cytokines and chemokines, as well as the upregulation of the activating receptors of these cytokines. The proinflammatory effects and absence of apoptosis, despite pro-apoptotic signaling of the Cache Valley PM on human lung cells appeared to stem from increased activation of the central pro-growth protein Akt with subsequent inactivation of the tumor suppressor P-TEN. These findings have indicated novel mechanisms of PM-related cellular stress and inflammation contributing needed information on what may be underlying mechanisms of PM associcated illnesses.

Styles APA, Harvard, Vancouver, ISO, etc.

33

Lebby, M. S. « Fabrication and characterisation of the Heterojunction field effect transistor (HFET) and the bipolar inversion channel field effect transistor (BIFCET) ». Thesis, University of Bradford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379863.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

34

Viala, Christophe. « Inversion géoacoustique temps réel de signaux large bande par grands fonds ». Phd thesis, Université du Sud Toulon Var, 2007. http://tel.archives-ouvertes.fr/tel-00258272.

Texte intégral

Résumé :

Les travaux présentés dans ce mémoire visent à développer une méthode globale d'inversion des paramètres géoacoustiques par grands fonds, dans le cadre du REA (Rapid Environmental Assesment ; Evaluation Rapide de l'Environnement)) acoustique opérationnel. La méthode développée utilise du Matched Impulse Response de signaux large bande. La finalité est de renseigner les sonaristes opérationnels du domaine de la lutte anti sous-marine sur les paramètres du fond, afin qu'il puissent améliorer l'évaluation des performances de leurs senseurs acoustiques. Ces travaux doivent fournir des enseignements utiles à la conception du prototype ftitur de REA acoustique STEREO de l'EPSHOM/CMO. La validation du concept s'opère dans cette thèse après la mise en place d'une démarche globale d'inversion basée sur l'ajustement des réponses impulsionnelles mesurées en transmission et des réponses irnpulsionnelles simulées par un modèle prenant en compte les paramètres du fond. Deux étapes d'inversion sont nécessaires visant à retrouver d'une part la configuration expérimentale puis ensuite les caractéristiques de la nature du fond. La méthode d'inversion développée est appliquée de façon quasi-automatisée à un jeu de données synthétiques complexes, élaborées à partir d'un simulateur temps réel de la propagation acoustique. Les essais sur données synthétiques permettent tout d'abord de valider la faisabilité de la méthode quant à ses performances de détection d'une transition horizontale de la porosité, et quant au respect de la contrainte opérationnelle du délai d'estimation. Ils permettent de qualifier de plus l'impact de l'effet Doppler sur les performances de l'inversion. Celle-ci est ensuite testée sur un jeu de données acoustiques et environnementales réelles mis à disposition par le Centre Militaire d'Océanographie de l'EPSHOM. Ces données correspondent à la campagne de REA HERACLES qui a eu lieu par grands fonds, cas défavorable pour l'inversion en raison du faible contenu informatif des signaux. La prise en compte d'un modèle numérique de terrain dans la méthode d'inversion permet de d'inverser un milieu évolutif avec la distance et de synthétiser l'ensemble des résultats de l'inversion des données d'une campagne typique de REA. Ces travaux permettent de dégager des configurations pour lesquelles l'inversion peut fonctionner en temps réel, ce qui valorise le principe de la méthode développée et les développements réalisés.

Styles APA, Harvard, Vancouver, ISO, etc.

35

Freeman, Justin K. « Effects of a Tape Cast, Air-Stirrup, and an Air-Stirrup Applied Over a Taped Ankle on Dynamic Ankle Inversion ». BYU ScholarsArchive, 2004. https://scholarsarchive.byu.edu/etd/1132.

Texte intégral

Résumé :

Objective: To compare the tape cast, and an Air-Stirrup/closed basketweave combination to the Air-Stirrup alone with respect to their effects on dynamic ankle inversion. Design and Setting: This study used a repeated measures design with the independent variables being the exercise bout and the ankle support method (4 levels: no support, Air-Stirrup only, Air-Stirrup/closed basketweave, and tape cast). The 2 dependent variables were total inversion and maximum inversion velocity. Measurements were taken before and after an exercise bout, and all trials were conducted in the university's human performance laboratory. Subjects: 16 subjects (11 male, 5 female, age 24.3 ± 1.8 years) with no ankle injury within 6 months prior to participation participated in this study. Measurements: Subjects stood on an inversion platform, which rotated 37° in the frontal plane, creating dynamic inversion of the ankle. Total inversion and maximum inversion velocity were calculated using electrogoniometers. A linear growth curve was used to model pre to post exercise differences. Results: There was a significant difference between the control and the 3 support methods for both variables. The effects of the Air-Stirrup/closed basketweave were similar to the effects of the Air-Stirrup alone. There was no significant difference between the tape cast and the Air-Stirrup. Conclusions: All 3 support methods significantly reduce total ankle inversion and maximum inversion velocity. When compared with the Air-Stirrup alone, the tape cast and the tape/brace combination both are similar in their effects on total ankle inversion and maximum inversion velocity.

Styles APA, Harvard, Vancouver, ISO, etc.

36

GAO, Jie. « Body Perception in Chimpanzees : A Comparative-Cognitive Study ». Kyoto University, 2020. http://hdl.handle.net/2433/258989.

Texte intégral

Résumé :

付記する学位プログラム名: 霊長類学・ワイルドライフサイエンス・リーディング大学院
Kyoto University (京都大学)
0048
新制・課程博士
博士(理学)
甲第22721号
理博第4630号
新制||理||1665(附属図書館)
京都大学大学院理学研究科生物科学専攻
(主査)准教授足立幾磨, 准教授後藤幸織, 教授高田昌彦
学位規則第4条第1項該当

Styles APA, Harvard, Vancouver, ISO, etc.

37

Dewick, Linda C. « Effects of haptic rehearsal on self-correction of letter and numeral shape reversals, inversions, transpositions and substitutions ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0011/MQ53149.pdf.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

38

Sun, Tawei. « Effects of solid solution on the high-low inversion of cristobalite and the stabilization of high cristobalite ». Diss., Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/54793.

Texte intégral

Résumé :

The inversion temperature of cristobalite was investigated by incorporating TiO₂, AlPO₄, and BPO₄ into the cristobalite phase using solid state reactions. The combination of TiO₂ and AlPO₄ proved to be most effective in lowering the inversion temperature of cristobalite. Phase diagrams at the high silica corner were constructed for the respective systems. High cristobalite was stabilized for compositions prepared from the CaO-Al2₂O₃-SiO₂ and CuO-Al₂O₃-SiO₂ system using sol-gel processing. The stabilization mechanism is attributed to the surface energy effect resulting from the formation of fine crystals. The structural evolution from the x-ray amorphous gel to high cristobalite was examined by FTIR and Raman spectroscopy. The thermal expansion of the stabilized high cristobalite was characterized by high temperature x-ray. Changes in bond angle continue to dominate the thermal expansion of high cristobalite.
Ph. D.

Styles APA, Harvard, Vancouver, ISO, etc.

39

Ionescu, Adrian M. « Modèles et méthodes associes a la caractérisation électrique du tmos : application aux technologies SOI ». Grenoble INPG, 1997. http://www.theses.fr/1997INPG0009.

Texte intégral

Résumé :

Les modeles et les methodes associees a la caracterisation electrique du tmos et particulierement, leur application aux technologies soi constituent l'objet de ce travail. Le premier chapitre est consacre a l'analyse du fonctionnement electrique du tmos/silicium massif ; nous proposons une expression unifiee en inversion faible, moderee et forte, pour le courant de drain, en regime lineaire, et son application a l'extraction de la tension de seuil. On analyse aussi l'influence des polarisations sur la sensibilite du tmos utilise comme capteur de champ magnetique. Le developpement theorique et experimental de la technique du pseudo-transistor mos, pour l'evaluation des materiaux soi sur plaquette, est donne dans le deuxieme chapitre. On y presente : la validation d'une nouvelle methode pour la determination de la duree de vie de generation dans les materiaux soi, l'etude de l'influence des resistances serie et des contacts schottky, la methode 3-pointes et l'evaluation du materiau unibond. Le troisieme chapitre est dedie a l'etude du tmos en technologie soi : on analyse le regime transitoire du courant de drain en inversion faible associe a la technique de zerbst et on effectue une etude systematique de la degradation des tmos/simox par irradiation gamma a de fortes doses (>1mrad).

Styles APA, Harvard, Vancouver, ISO, etc.

40

Cunningham, Heidi Margaret. « The effect of non-inversion tillage on farmland birds, soil and surface-active invertebrates and surface seeds ». Thesis, Open University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417462.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

41

Puig, Font Marta. « Functional analysis of position effects of inversion 2j in Drosophila buzzatii : gene CG13617 silencing and its adpative significance ». Doctoral thesis, Universitat Autònoma de Barcelona, 2010. http://hdl.handle.net/10803/32108.

Texte intégral

Résumé :

És sabut de fa molt temps que les inversions cromosòmiques son mantenides per selecció natural a les poblacions de Drosophila. No obstant, els mecanismes moleculars que generen aquest valor adaptatiu encara no es coneixen. A les poblacions naturals de D. buzzatii, la inversió 2j forma un polimorfisme equilibrat amb l’ordenació 2st, en què els individus 2j tenen una mida més gran y un temps de desenvolupament més llarg en comparació amb els 2st. En aquest treball hem posat a provat la hipòtesi de que un efecte de posició d’un dels punts de trencament podria ser la causa d’aquests canvis fenotípics. Per a fer-ho hem analitzat l’expressió d’un gen adjacent al punt de trencament proximal, CG13617, en línies de D. buzzatii amb i sense la inversió 2j. Hem trobat que els embrions 2j presenten un nivell d’expressió de CG13617 cinc vegades menor causat per un RNA antisense originat en una còpia d’un transposó de la família Galileo inserit al punt de trencament. Les conseqüències funcionals de la reducció de l’expressió de CG13617 s’han investigat utilitzant la tècnica de RNA interferència per reproduir aquest silenciament a D. melanogaster. Els experiments de microarrays i RT-PCR en temps real comparant larves de primer estadi amb i sense expressió de CG13617 han revelat que 41 gens mostren nivells d’expressió reduïts quan CG13617 és silenciat, mentre que cap gen presenta un increment. A més, hi ha un excés significatiu de gens implicats en la replicació del DNA i el cicle celular entre els afectats pel silenciament de CG13617. Nou de deu d’aquests gens van ser analitzats a D. buzzatii i també tenen un nivell d’expressió reduït en embrions 2j, però no en larves de primer estadi, una fase en què la diferència d’expressió de CG13617 entre ordenacions cromosòmiques és menor i el RNA antisense ja no es transcriu. Per a esbrinar la possible funció d’aquest gen hem dut a terme un exhaustiu anàlisi de seqüències nucleotídiques i proteiques en els 12 genomes de Drosophila disponibles i també en altres organismes. La proteïna CG13617 conté un dit de zinc tipus C2H2 molt conservat, tres regions que poden formar coiled coils, dues seqüències PEST i senyals de localització i exportació nuclear. També presenta similitud amb la proteïna humana DZIP1 i amb Iguana, un component de la via de senyalització Hedgehog al peix zebra, fet que indica que el seu paper dins la cèl·lula podria estar relacionat amb el transport de factors de transcripció cap a dins i cap a fora del nucli. Aquests resultats suggereixen que el gen CG13617 podria estar implicat en la regulació de la replicació del DNA i que l’efecte de posició en els portadors de la inversió 2j podria contribuir a explicar les diferències fenotípiques observades entre els individus 2st i 2j, així com el valor adaptatiu d’aquesta inversió.
Chromosomal inversions have been known for a long time to be maintained by natural selection in Drosophila populations. However, the molecular mechanisms underlying their adaptive value remain uncertain. In D. buzzatii natural populations, inversion 2j forms a balanced polymorphism with the 2st arrangement, in which 2j individuals have a larger size and a longer developmental time compared to 2st carriers. In this work we tested the hypothesis that a position effect of one of the inversion breakpoints could be the cause of these phenotypic changes by analyzing the expression of a gene adjacent to the proximal breakpoint, CG13617, in D. buzzatii lines with and without inversion 2j. We have found that in 2j embryos an antisense RNA originated in a copy of a Galileo family transposon inserted at the breakpoint causes a 5-fold decrease of the expression level of CG13617. In order to investigate the functional consequences of the reduction in CG13617 expression, we have used RNA interference to reproduce this silencing in D. melanogaster. Microarray and real-time RT-PCR experiments comparing first instar larvae with and without CG13617 expression revealed that 41 genes show reduced expression levels when CG13617 is silenced, while none is up-regulated. Interestingly, genes involved in DNA replication and cell cycle are significantly enriched among those affected by CG13617 silencing. Nine out of ten of these genes analyzed in D. buzzatii also show a reduced expression level in 2j embryos, but not in first instar larvae, a stage where the CG13617 expression difference between chromosomal arrangements is lower and the antisense RNA is no longer transcribed. To gain insight into the potential function of this gene we have carried out a comprehensive nucleotide and protein sequence analysis in the 12 available Drosophila genomes and also in other organisms. CG13617 protein contains a conserved C2H2 zinc finger, three coiled coil regions, two PEST sequences, and putative nuclear localization and export signals, and shows similarity to human DZIP1 and zebrafish Iguana (a component of the Hedgehog signaling pathway) proteins, which indicates that its cellular role could be related to the transport of transcription factors in and out of the nucleus. These results suggest that gene CG13617 could be involved in the regulation of DNA replication and that the position effect in 2j carriers might contribute to explain the phenotypic differences observed between 2st and 2j individuals as well as the adaptive value of the inversion.

Styles APA, Harvard, Vancouver, ISO, etc.

42

Joly, Yohan. « Etude des fluctuations locales des transistors MOS destinés aux applications analogiques ». Thesis, Aix-Marseille 1, 2011. http://www.theses.fr/2011AIX10138/document.

Texte intégral

Résumé :

Les fluctuations électriques des composants sont une limitation à la miniaturisation des circuits. Malgré des procédés de fabrications en continuelle évolution, les variations des caractéristiques électriques dues au désappariement entre deux dispositifs limitent les performances des circuits. Concernant les applications à faible consommation, ces fluctuations locales peuvent devenir très critiques. Dans le contexte du développement d’une technologie CMOS 90nm avec mémoire Flash embarquée pour des applications basse consommation, l’appariement de transistors MOS est étudié. Une analyse de l’impact du dopage de grille des transistors NMOS est menée. L’étude se focalise sur l’appariement en tension des paires différentielles polarisées dans la zone de fonctionnement sous le seuil. Il est démontré que cet appariement peut être dégradé à cause de l’effet « hump », c'est-à-dire la présence de transistors parasites en bord d’active. Un macro-modèle permettant aux concepteurs de modéliser cet effet est présenté. Il est étudié au niveau composant, au niveau circuit et en température. Enfin, une étude de la dégradation de l’appariement des transistors MOS sous stress porteurs chauds est réalisée, validant un modèle de dégradation. Des transistors octogonaux sont proposés pour supprimer l’effet « hump » et donnent d’excellents résultats en termes d’appariement ainsi qu’en fiabilité
Electrical fluctuations of devices limit chip miniaturization. Despite manufacturing processes in continuous evolution, circuit performances are limited by electrical characteristics variations due to mismatch between two devices. Concerning low power applications, local fluctuations can become very critical. In the context of development of a 90nm CMOS technology with Embedded Flash memory for low power applications, MOS transistors matching is studied. A study of NMOS transistors gate doping impact is conducted. Study focuses on voltage matching of differential pairs biased under threshold. It is demonstrated that this matching can be degraded due to « hump » effect, meaning presence of parasitic devices on active edge. A macro-model allowing designers to model this effect is presented. It is studied at device level, circuit level and for different temperatures. Finally, a degradation study of MOS transistors mismatch under Hot Carriers Injection stress is performed, validating a degradation model. Octagonal devices are proposed to suppress « hump » effect and give good results in terms of matching as well as reliability

Styles APA, Harvard, Vancouver, ISO, etc.

43

Neuman, Erica L. « The Social and Psychological Costs of Avoiding Taxes : An Archival Analysis of Firm and Peer Effects ». Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case1586462862248405.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

44

Ars, Sébastien. « Caractérisation des émissions de méthane à l'échelle locale à l'aide d'une méthode d'inversion statistique basée sur un modèle gaussien paramétré avec les données d'un gaz traceur ». Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLV030/document.

Texte intégral

Résumé :

L'augmentation des concentrations de méthane dans l'atmosphère, directement imputable aux activités anthropiques, induit une accentuation de l'effet de serre et une dégradation de la qualité de l'air. Il existe encore à l'heure actuelle de grandes incertitudes concernant les estimations des émissions des dfférentes sources de méthane à l'échellelocale. Une meilleure caractérisation de ces sources permettrait de mettre en place des politiques d'adaptation et d'att énuation efficaces afin de réduire ces émissions. Nous avons développé une nouvelle méthode de quantificationdes émissions de méthane à l'échelle locale basée sur la combinaison de mesures atmosphériques mobiles et d'un modèle gaussien dans le cadre d'une inversion statistique. Les concentrations atmosphériques du méthane sont mesuréesainsi que celles d'un gaz traceur émis à un flux connu. Ces concentrations en gaz traceur sont utilisées pour sélectionnerla classe de stabilité représentant le mieux les conditions atmosphériques dans le modèle gaussien ainsi qu'à paramétrerl'erreur associée aux mesures et au modèle dans l'inversion statistique. Dans un premier temps, cette nouvelle méthoded'estimation des émissions de méthane a été testée grâce à des émissions contrôlées de traceur et de méthane dontles sources ont été positionnées suivant différentes configurations. J'ai ensuite appliqué cette méthode à deux sites réels connus pour leurs émissions de méthane, une exploitation agricole et une installation de distribution de gaz, afin de tester son applicabilité et sa robustesse dans des conditions plus complexes de répartition des sources de méthane. Cette méthode a permis d'obtenir des estimations des émissions totales des sites robustes prenant en compte la localisation du traceur par rapport aux sources de méthane. L'estimation séparéedes émissions des différentes sources d'un site s'est révélée fortement dépendante des conditions météorologiques durant les mesures. Je me suis ensuite focalisé sur les émissions de méthane associées au secteur des déchets en réalisant un certain nombre de campagnes de mesures au sein d'installations de stockagedes déchets non dangereux et de stations d'épuration. Les résultats obtenus pour ces différents sites montrent la grandevariabilité des émissions de méthane dans le secteur des déchets
The increase of atmospheric methane concentrations since the beginning of the industrial era is directly linked to anthropogenic activities. This increase is partly responsible for the enhancement of the greenhouse effect leading to a rise of Earth's surface temperatures and a degradation of air quality. There are still considerable uncertainties regarding methane emissions estimates from many sources at local scale. A better characterization of these sources would help the implementation of effective adaptation and mitigation policies to reduce these emissions.To do so, we have developed a new method to quantify methane emissions from local sites based on the combination of mobile atmospheric measurements, a Gaussian model and a statistical inversion. These atmospheric measurements are carried out within the framework of the tracer method, which consists in emitting a gas co-located with the methane source at a known flow. An estimate of methane emissions can be given by measuring the tracer and methane concentrations through the emission plume coming from the site. This method presents some limitations especially when several sources and/or extended sources can be found on the studied site. In these conditions, the colocation of the tracer and methane sources is difficult. The Gaussian model enables to take into account this bad collocation. It also gives a separate estimate of each source of a site when the classical tracer release method only gives an estimate of its total emissions. The statistical inversion enables to take into account the uncertainties associated with the model and the measurements.The method is based on the use of the measured tracer gas concentrations to choose the stability class of the Gaussian model that best represents the atmospheric conditions during the measurements. These tracer data are also used to parameterize the error associated with the measurements and the model in the statistical inversion. We first tested this new method with controlled emissions of tracer and methane. The tracer and methane sources were positioned in different configurations in order to better understand the contributions of this method compared to the traditional tracer method. These tests have demonstrated that the statistical inversion parameterized by the tracer gas data gives better estimates of methane emissions when the tracer and methane sources are not perfectly collocated or when there are several sources of methane.In a second time, I applied this method to two sites known for their methane emissions, namely a farm and a gas distribution facility. These measurements enabled us to test the applicability and robustness of the method under more complex methane source distribution conditions and gave us better estimates of the total methane emissions of these sites that take into account the location of the tracer regarding methane sources. Separate estimates of every source within the site are highly dependent on the meteorological conditions during the measurements. The analysis of the correlations on the posterior uncertainties between the different sources gives a diagnostic of the separability of the sources.Finally I focused on methane emissions associated with the waste sector. To do so, I carried out several measurement campaigns in landfills and wastewater treatment plants and I also used data collected on this type of sites during other projects. I selected the most suitable method to estimate methane emissions of each site and the obtained estimates for each one of these sites show the variability of methane emissions in the waste sector

Styles APA, Harvard, Vancouver, ISO, etc.

45

Bouvier, Clément. « Barres d’avant-côte et trait de côte : dynamique, couplage et effets induits par la mise en place d’un atténuateur de houle ». Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0088/document.

Texte intégral

Résumé :

Ces dernières années, de nouvelles stratégies ciblant un accompagnement de la mobilité du trait de côte plutôt que sa fixation ont vu le jour. Parmi celles-ci, les ouvrages atténuateur de houle visent à protéger la côte en dissipant l’énergie des vagues par déferlement bathymétrique, tout en restant invisibles depuis la plage. Leur utilisation a toutefois eu des effets contrastés et les processus hydro-sédimentaires induits par ces structures restent mal connus. L’objectif général de ce travail est de mieux comprendre les effets de ces atténuateurs de houle sur la morphodynamique littorale, notamment sur des sites où l’évolution de l’avant-côte est complexe et dynamique. L’observation des effets induits par un atténuateur de houle installé au lido de Sète (Golfe du Lion), sur la dynamique littorale est réalisée via un dispositif vidéo qui permet de caractériser l’évolution morphologique du système. En s’appuyant sur une méthode automatique de correction des images développée dans le cadre de cette thèse, l’estimation de la bathymétrie par inversion de la célérité des vagues et ses erreurs associées sont évaluées pour la première fois en Méditerranée. Les observations montrent que l’atténuateur de houle impacte de manière importante la morphologie et la dynamique des barres sableuses pré-littorales et révèlent que l’élargissement de la plage résulte principalement de son couplage avec la nouvelle forme de barre plus linéaire. Le modèle morphodynamique 2DBeach est ensuite implémenté sur Sète et sur un second site atelier en Australie où un récif artificiel de taille et de forme différente a été mis en place. Les simulations réalisées permettent de déterminer les circulations induites par ces ouvrages ainsi que les évolutions sédimentaires associées. Enfin, ce travail met en lumière les différents processus physiques contrôlant l’influence d’un atténuateur de houle sur les évolutions morphologiques des barres sableuses pré-littorales et du trait de côte, et renforce des connaissances essentielles à la gestion durable des plages sableuses
In recent years, traditional coastal defense strategy has become increasingly unpopular as it is costly and lastingly scars the landscape with sometimes limited effectiveness or even adverse impact. Mimicking natural reefs, submerged breakwaters aims to protect the coast, decreasing wave energy through wave breaking offshore with the advantage of remaining invisible from the beach. The general objective of this work is to better understand the different morphodynamic processes that interact in the presence of these structures, especially for complex beach morphology with highly dynamic sandbars. The observation of the effects induced by a submerged breakwater deployed at the Lido of Sète (Gulf of Lions) on the morphological response is performed using a video monitoring system. Based on an automatic method for image correction developed in this thesis, a video-derived depth inversion algorithm was tested to infer nearshore bathymetry from remotely-sensed wave parameters. Our observations show that the submerged breakwater had a profound impact on the shoreline-sandbar system and suggest that, on barred beaches, the role of the sandbar is critical to shoreline response to the implementation of such a structure. The expected salient formation was not observed and, instead, shoreline coupled to the modified sandbar geometry, which resulted in a slight seaward migration of the shoreline in the lee of the structure. In order to characterize the nearshore circulation induced by these structures and to better assess sediment transport, the morphodynamic model 2DBeach was then implemented on Sète and at another beach in Australia where an artificial reef of different size and shape has been deployed. This work allows a better understanding of the influence of a submerged breakwater on the morphological evolution of sandbars and shoreline on time scales from storm to years, and provides new insight into nearshore system response to better design sustainable management of sandy beaches

Styles APA, Harvard, Vancouver, ISO, etc.

46

Wolfram, Susann. « Differential behaviour of the medial and lateral heads of gastrocnemius during plantarflexion : the effect of calcaneal inversion and eversion ». Thesis, Manchester Metropolitan University, 2017. http://e-space.mmu.ac.uk/618921/.

Texte intégral

Résumé :

Gastrocnemius medialis (GM) and lateralis (GL) have been considered as plantarflexors of the talocrural joint but also contribute to inversion and eversion of the calcaneus at the subtalar joint. The contractile behaviour has predominately been investigated for GM and findings have been generalised to both gastrocnemii. However, differences in their morphology and, possibly, function have been reported. The purpose of this thesis was to investigate differential contractile behaviour of GM and GL and the effect of inversion/eversion of the calcaneus. The effect of calcaneal inversion/eversion due to standing posture and due to positioning was investigated. A new imaging-based method to assess calcaneal inversion/eversion during standing was developed. Using this method, the validity of the clinically applied method could not be established. Achilles tendon moment arm is unaffected by calcaneal inversion/eversion posture and position. An exploratory investigation into the application of the centre-of-rotation method to determine inversion/eversion Achilles tendon moment arms was also undertaken. Contractile behaviour of GM and GL was unaffected by calcaneal inversion and eversion but fascicle length, pennation angle and tendon length differed between GM and GL. A comparison of GM and GL showed that fascicle behaviour is similar between them but GM tendon elongation and strain exceeded GL tendon elongation and strain, especially at higher contraction levels. The contraction levels at which tendon strain differences occur are dependent on the amount of calcaneal inversion/eversion position. GM and GL differ significantly in their anatomical composition. Adaptations of GM and GL to calcaneal inversion/eversion appear to occur at the tendon level rather than the fascicle level. Given the differential function of GM and GL reported in the literature and the findings of this thesis, it is suggested that GM and GL could be referred to as two separate muscles instead of two heads of the same muscle. It is, furthermore, suggested that GM and GL are not bi-articular but tri-articular due to their actions at the subtalar joint.

Styles APA, Harvard, Vancouver, ISO, etc.

47

Dahrouj, Ahmad Sami. « The development of a novel system to assess the effect of sudden foot and ankle inversion/supination on the musculoskeletal system ». Thesis, University of Dundee, 2011. https://discovery.dundee.ac.uk/en/studentTheses/dffc0272-143a-41cc-98d2-a00160606e65.

Texte intégral

Résumé :

Ankle sprains are one of the most common type of sports injury. They occur most frequently when the foot is in a supine or inverted position. Recovery from an ankle sprain can take from one and up to 26 weeks depending on the severity of the injury. During that period the individual will be unable to participate in any meaningful sports activity and as such it is important to be able to prevent the occurrence of such injuries. Prevention of ankle sprain injuries would require a better understanding of the risk factors of this injury. Several studies attempted to assess such risk actors by inducing foot inversion or supination however the platforms used in these studies were shown to be limited. Hence the main aim of this project is to develop a system that can be used to assess the effect of sudden foot and ankle inversion/supination on the musculoskeletal system of dynamic subjects (e.g. walking, running, jumping, etc.). For this purpose a three degrees of freedom (DOF) rotating platform has been designed, manufactured and installed in the Institute of Motion Analysis and Research (IMAR) Sports Laboratory. The platform rotates around 3 different axes allowing inversion or supination of the foot and ankle of dynamic subjects. The degree of rotation around each axis can easily be set by the researcher/operator. A strain gauge was used to detect foot strike to the platform. As a safety measure laser emitter/receivers check that the entire foot is on the footplate before the platform rotates. Optical encoders provide essential feedback of rotation angles, speed and acceleration. The necessary software and user interface for controlling the platform were also written and tested. The platform was synchronised with a bilateral four-channel EMG (electromyography) system and a 12 camera Vicon® MX-13 system thus allowing measurement of muscle activity and kinematic data during the supination of the foot. A set of software modules were written to allow automated management and processing of the data generated by the new system. The new system was then implemented in a study to validate it and to assess the role of shoes in ankle sprains. In this study, subjects would walk in three different foot conditions: barefoot, and with two different types of sports shoes, along the walkway of the Sports Laboratory where the platform was fitted. When a subject steps on the embedded platform, it rotates causing the subject's foot to supinate. At the same time, the EMG data from the peroneus longus, tibialis anterior, and lateral gastrocnemius muscles are recorded, along with the kinematics of the subject's whole body. The obtained results demonstrated the validity of the newly developed system. Data from the validation study also revealed increased muscle activity following induced foot supination in shod conditions compared to barefoot. Muscle activity of the rotating platform step was found to be significantly higher than the steps before and after. The platform rotation was also found to have an observable effect on body kinematics. The newly developed system is hoped to help provide a better understanding of the risk factors of ankle sprain injury and how to prevent this injury. The system can be used to help improve the design of current footwear and identify which footwear provides better protection against ankle sprain injury. The system can also be used to assess the effectiveness of different ankle injury rehabilitation schemes and different training programs that aim to reduce ankle sprain injuries. The new system can be utilised to identify individuals who are at risk of sustaining an ankle sprain injury. The system can also be utilised in studies outside the scope of ankle sprain injuries.

Styles APA, Harvard, Vancouver, ISO, etc.

48

Lee, Irene W. 1977. « An analytic examination of the effect of the stratosphere on surface climate through the method of piecewise potential vorticity inversion ». Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/17677.

Texte intégral

Résumé :

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2003.
Includes bibliographical references (leaves 75-77).
An analytic study was performed to examine the effect of the stratosphere on the surface of the earth. The method of piecewise potential vorticity inversion was employed in the diagnosis of the magnitude of and dynamics behind the stratosphere-surface link in both the transient and stationary cases. The potential vorticity inversion results in both the transient and stationary models indicated that the stratosphere possesses a significant effect at the surface of the earth. It was determined that, compared to the stratosphere as a whole, it was primarily the lower stratosphere that had the most significant impact at the surface of the earth. The results of this analytic study therefore indicate that in modeling the surface of the earth, the dynamics detailed here between the lower stratosphere and surface must be included for the modeled surface weather or climate simulations to be accurate.
by Irene W. Lee.
S.M.

Styles APA, Harvard, Vancouver, ISO, etc.

49

Malgas, Samkelo. « The effect of GH family affiliations of mannanolytic enzymes on their synergistic associations during the hydrolysis of mannan-containing substrates ». Thesis, Rhodes University, 2015. http://hdl.handle.net/10962/d1017909.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

50

Drouet, Stéphane. « Analyse des données accélérimétriques pour la caractérisation de l'aléa sismique en France métropolitaine ». Toulouse 3, 2006. http://www.theses.fr/2006TOU30062.

Texte intégral

Résumé :

Ce travail est consacré à l'étude des données accélérométriques de la france métropolitaine, issues du Réseau Accélérométrique Permanent (RAP), en cours d'installation depuis 1996, pour caractériser l'aléa sismique. Il existe de nombreux modèles empiriques de prédiction des mouvements forts valables pour les régions sismiquement très actives (USA, Japon. . . ), mais leur utilisation dans le contexte français nécessite la ré-évaluation de paramètres tels que les magnitudes et les conditions de site. Dans un premier temps, l'analyse des données de séismes modérés a permis d'établir une échelle homogène de magnitudes issues du moment sismique. Par ailleurs, les réponses de site des stations du réseau RAP ont été calculées pour les Pyrénées, les Alpes et le fossé Rhénan. Enfin, les phénomènes d'atténuation au niveau de la France semblent présenter des variations régionales. En se basant sur les résultats précédents, l'applicabilité de certains modèles empiriques de mouvements forts a été démontrée, à partir des séismes les plus importants enregistés par le RAP
The aim of this study is to analyse the vertical structure of the low troposphere during the ESCOMPTE campaign in relation with transport and diffusion of pollutants. This analysis shows the difficulty to define a boundary layer. It allows us to highlight a complexe superposition of several internal boundary layers, particularly near the coast. The study of the layer where pollution may be accumulated or diluted pointed out the fact that pollution is trapped near the surface, close to the coastline under sea-breeze conditions whereas it is advected over the mountains where the boundary layers are deeper. During sea-breeze conditions, the ozone concentration is paradoxically weak near the sources at the coastline (titration). Over the mountains, the strong developments of the boundary layers result in a mixing between the highly polluted low troposphere and the surface which enhances the ozone concentration

Styles APA, Harvard, Vancouver, ISO, etc.

Thèses sur le sujet « Effetto inversione »

Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres