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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
711

Livskvalitet hos högkänsliga personer : en studie om högkänslighet, självmedkänsla och personlighet / Quality of life for Highly Sensitive Persons : a study on high sensitivity, self-compassion and personality

Brongers, Rosalinde January 2015 (has links)
Tjugo procent av alla människor är högkänsliga (HSP = Highly Sensitive Person), vilket innebär att de är födda med ett känsligt nervsystem. Många HSP upplever negativa konsekvenser i sin vardag som påverkar livskvaliteten. Eftersom gruppen HSP är så stor och kopplingen HSP, livskvalitet och självmedkänsla inte specifikt har undersökts, var det relevant att göra den här enkätundersökningen. De undersökta frågeställningar är: Finns det inom gruppen HSP angående variablerna: Livskvalitet, Självmedkänsla, Högkänslighet, BIS, BAS, Extraversion och Neuroticism (a) signifikanta samband mellan samtliga variablerna? (b) Till vilken grad förklarar variablerna Livskvalitet och Högkänslighet? (c) Finns det könsskillnader angående samtliga variablerna? (d) Finns det ett positivt samband mellan Högkänslighet och Ålder? De 111 deltagare var medlemmar i Sveriges Förening för Högkänsliga och samtliga var enligt självskattning HSP, som bekräftades av insamlade data. Deltagargruppen bestod av 93 kvinnor (84%) och 18 män (16%) och genomsnittsålder var 50 år, där lägsta åldern var 35 år och högsta 70. Samtliga frågeställningar har besvarats genom analysmetoderna: Pearsons korrelationsanalys, Standard Multipel Linjär Regression och T-test. Det viktigaste resultatet var att kopplingen mellan HSP och självmedkänsla bidrog med ny kunskap, där slutsatsen blev att utövandet av självmedkänsla kan bidra till att aktivt öka graden av livskvalitet för HSP. Det starkaste sambandet i studien förelåg mellan BIS och neuroticism, vilket betyder att vid en ökning av BIS, ökar graden av negativ affekt och vice versa; resultatet låg i linje med tidigare forskning. Två oväntade resultat var att (a) drivkraften (BASDrive) predicerade högkänslighet mest till skillnad från litteraturen som pekar åt BIS och neuroticism som skulle ha starkast koppling och (b) att graden av högkänslighet sjönk vid ökad ålder; vilket talar emot tidigare forskning. Uppsatsen är en relevant informationskälla för HSP och alla andra som interagerar med HSP. / Twenty percent of all people are highly sensitive (HSP = Highly Sensitive Person) which means that they are born with a sensitive nervous system. Many HSP's are experiencing negative consequences in their everyday lives that affect their quality of life. As the group HSP is large and the correlation between HSP, quality of life and self-compassion is not specifically is investigated, the present study was relevant. The examined questions are: Is there within the group of HSP regarding Quality of Life, Self-compassion, High sensitivity, BIS, BAS, Extraversion and Neuroticism (a) significant correlations between the variables? (b) To what extend do the variables explain Quality of Life and High Sensitivity? (c) Are there gender differences regarding the variables? (d) Is there a positive correlation between High Sensitivity and Age? The 111 participants were members of the Sveriges Förening för Högkänsliga and all were HSP according to self-assessment, which also was confirmed by the data collected. The group of participants consisted of 93 women (84%) and 18 men (16%) and the average age was 50, where the lowest age was 35 years and the highest 70. All questions were answered by these analytical methods: Pearson's correlation analysis, Standard Multiple Linear Regression and T-test. The main outcome was that the link between HSP and self-compassion contributed to new knowledge, which concluded that the practice of Self-compassion can help to actively increase the level of quality of life for HSP's. The strongest correlation in the study was between BIS and neuroticism, which means that at an increase of BIS, the degree of negative affect also increased and vice versa; the result was in line with previous research. Two unexpected results were that (a) the driving force (BASDrive) predicted high sensitivity most, unlike the literature suggesting that BIS and neuroticism would have the strongest connection and (b) the degree of high sensitivity decreased with increase in age; which contradicts earlier research. The essay is a relevant source of information for the HSP and all others who are interacting with HSP.
712

Análise de Sensibilidade Topológica / Topological Sensitivity Analysis

Antonio André Novotny 13 February 2003 (has links)
The Topological Sensitivity Analysis results in a scalar function, denoted as Topological Derivative, that supplies for each point of the domain of definition of the problem the sensitivity of a given cost function when a small hole is created. However, when a hole is introduced, it is no longer possible to stablish a homeomorphism between the domains. Due to this mathematical difficulty the Topological Derivative may become restrictive, nevertheless be extremely general. Thus, in the present work it is proposed a new method to calculte the Topological Derivative via Shape Sensitivity Analysis. This result, formally proved through a theorem, leads to a simpler and more general methodology than the others found in the literature. The Topological Sensitivity Analysis is performed for several Engineering problems, and the obtained results are used to improve the design of mechanical devices by introducing holes. The same theory developed to calculate the Topological Derivative is used to determine the sensitivity of the cost function when a small incrustation is introduced in each position of the domain, resulting in a novel concept denoted as Configurational Sensitivity Analysis, being discussed some possible applications in the context of Inverse Problems and modelling of phenomena that experiment changes in the physical properties of the medium. Thus, the methodology developed in the present work results in a framework with potential applications in Topology Optimization, Inverse Problems and Mechanical Modelling, which may be seen, from now on, not only as a method to calculate the Topological Derivative, but as a promising research area in Computational Modelling. / A análise de Sensibilidade Topológica resulta em uma função escalar, denominada Derivada Topológica, que fornece para cada ponto do domínio de definição do problema a sensibilidade de uma dada função custo quando um pequeno furo é criado. No entanto, ao introduzir um furo, não é mais possível estabelecer um homeomorfismo entre os domínios envolvidos. Devido a essa dificuldade matemática a Derivada Topológica pode se tornar restritiva, não obstante seja extremamente geral. No presente trabalho, portanto, é proposto um novo método de cálculo da Derivada Topológica via Análise de Sensibilidade à Mudança de Forma. Este resultado, formalmente demonstrado através de um teorema, conduz a uma metodologia mais simples e geral do que as demais encontradas na literatura. A Análise de Sensibilidade Topológica é então realizada em diversos problemas da Engenharia e os resultados obtidos são empregados para melhorar o projeto de componentes mecânicos mediante a introdução de furos. A mesma teoria desenvolvida para calcular a Derivada Topológica é utilizada para determinar a sensibilidade da função custo ao introduzir uma pequena incrustação numa dada posição do domínio, resultando em um novo conceito denominado Análise de Sensibilidade Configuracional, sendo discutidas suas possíveis aplicações no contexto de Problemas Inversos e de modelagem de fenômenos que experimentam mudanças nas propriedades físicas do meio. Assim, a metodologia aqui desenvolvida é uma ferramenta em potencial tanto de Otimização Topológica quanto de Problemas Inversos e de Modelagem Mecânica, podendo ser vista, a partir de agora, não somente como um método de cálculo da Derivada Topológica, mas como uma promissora área de pesquisa em Modelagem Computacional.
713

Sensibilidade ambiental ao óleo para rodovias: estudo de caso de trecho da Rodovia Washington Luís (SP 310) / Environmental sensitivity to oil for highways: case study of a strech of Washington Luís Highway (SP 310)

Ribeiro, Daniela Ferreira [UNESP] 24 April 2017 (has links)
Submitted by Daniela Ferreira Ribeiro null (danifebeiro@gmail.com) on 2017-06-12T14:19:26Z No. of bitstreams: 1 DISSERTAÇÃO VERSÃO FINAL.pdf: 132240823 bytes, checksum: 795a421f499ffbc710453daf2ff67f0e (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-06-13T16:43:44Z (GMT) No. of bitstreams: 1 ribeiro_df_me_rcla.pdf: 132240823 bytes, checksum: 795a421f499ffbc710453daf2ff67f0e (MD5) / Made available in DSpace on 2017-06-13T16:43:45Z (GMT). No. of bitstreams: 1 ribeiro_df_me_rcla.pdf: 132240823 bytes, checksum: 795a421f499ffbc710453daf2ff67f0e (MD5) Previous issue date: 2017-04-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A presente pesquisa propõe um índice de sensibilidade ambiental ao óleo para os parâmetros físicos adjacentes a um trecho da rodovia Washington Luís (SP 310) a fim de colaborar com o desenvolvimento de Cartas de Sensibilidade Ambiental ao Óleo (Cartas SAO) para ambientes adjacentes a rodovias. As Cartas SAO constituem-se em ferramentas interessantes para o auxílio na tomada de decisões em caso de acidentes envolvendo derrames de óleo, visto que apresentam as áreas com maior e menor sensibilidade, colaborando assim nas operações de emergência e com a escolha dos procedimentos adequados de limpeza e remoção. O índice de sensibilidade ambiental para a rodovia (IST) baseou-se em metodologias propostas pela National Oceanic and Atmospheric Administration (NOAA), pelo Ministério do Meio Ambiente e em trabalhos realizados em ambientes terrestres sujeitos a esse tipo de acidente. Os estudos envolvendo as Cartas SAO possuem ampla aplicação nos ambientes litorâneos e fluviais, mas ainda apresentam-se incipientes em ambientes terrestres, entretanto estes devem ser priorizados, pois são frequentes acidentes com derrames de óleo e derivados de petróleo, principalmente próximos a rodovias, visto que o modal rodoviário é um dos mais utilizados atualmente para o transporte desses produtos no Brasil. A metodologia aplicada baseou-se na técnica de compartimentação fisiográfica, pois o IST deve apresentar as características homogêneas de segmentos de interesse e ser representado de forma linear, seguindo as bases propostas pelo Ministério do Meio Ambiente (MMA). A compartimentação foi realizada por meio da interpretação de imagens orbitais da área de estudo, apoiada por mapas básicos e trabalhos de campo, a fim de determinar zonas homólogas e classifica-las quanto à sensibilidade ambiental ao óleo. Foram delimitados 17 compartimentos, que foram classificados quanto à declividade, textura e espessura do solo, profundidade do nível d’água e permeabilidade. Para cada variável foi determinado um grau parcial de sensibilidade ambiental classificado entre baixo, médio e alto. Foram atribuídos pesos, baseados na importância relativa das diferentes classes, que foram então combinadas de forma ponderada pela ferramenta Weighted Sum, do software ArcGIs, o que possibilitou uma análise integrada dos fatores envolvidos. Os valores finais de sensibilidade ambiental ao óleo foram atribuídos com base no sistema de índices proposto pela NOAA, que utiliza índices de sensibilidade de 1 a 10, sendo este último o mais sensível. No geral, o trecho da rodovia estudado apresentou valores altos e intermediários de sensibilidade, não apresentando os índices de 1 a 4. As áreas mais sensíveis foram classificadas como índices 8 e 9. Esses valores relacionaram-se principalmente à alta ou média sensibilidade das variáveis declividade, espessura do solo e profundidade do nível d’água em grande parte da área de estudo. Conclui-se que a metodologia de sensibilidade ambiental ao óleo para áreas terrestres, especificamente para o modal rodoviário, mostrou-se adequada ao determinar os ambientes com maior e menor sensibilidade, entretanto os parâmetros de análise devem ser ajustados de acordo com a realidade local dos ambientes. Além disso, o uso de ferramentas geotecnológicas mostrou-se eficaz, tornando essa metodologia acessível para estudos futuros. / The present study proposes an environmental sensitivity index to oil for the physical parameters adjacent to a section of the Washington Luís Highway (SP 310), in order to collaborate with the development of Environmental Sensitivity Map for Oil Spills for areas adjacent to highways. The Environmental Sensitivity Maps for Oil Spills are interesting tools to assist in decision-making in the occurrence of accidents involving oil spills, seeing that they present the areas with greater and lesser sensitivity, thus collaborating in the emergency operations, aiding the choice of the appropriate procedures of cleaning and removal. The Environmental Sensitivity Index for Highways (STI) based on the methodologies proposed by the National Oceanic and Atmospheric Administration (NOAA), the Ministry of the Environment and studies performed in terrestrial environments subject to this type of accident. The studies involving Environmental Sensitivity Maps have wide application in the coastal and fluvial environments, but are still incipient in terrestrial environments, however these should be prioritized, since accidents with oil spills and petroleum derivatives are frequent, especially near roads, seen that the road modal is one of the most used currently for the transportation of these products in Brazil. The applied methodology was based on the technique of physiographic subdivision, on this account the IST have to present the homogeneous characteristics of segments of interest and be represented in a linear way, based on the proposed by the Ministry of the Environment (MMA). The compartmentalization was performed through the interpretation of orbital images of the study area, supported by basic maps and field work, in order to determine homologous zones and classify them as to the environmental sensitivity to oil. Seventeen compartments were delimited, which were classified as slope, soil texture and thickness, water depth and permeability. For each variable a partial degree of environmental sensitivity classified as low, medium and high was determined. Weights were assigned based on the relative importance of the different classes, which were then combined in a weighted way by the “Weighted Sum” tool of the ArcGIs software, which made possible an integrated analysis of the factors involved. The final values of environmental sensitivity to oil were attributed based on the index system proposed by NOAA, which uses sensitivity indexes from 1 to 10, the latter being the most sensitive. In general, the section of the highway studied presented high values and intermediate sensitivity, and did not present indexes from 1 to 4. The most sensitive areas were classified as indexes 8 and 9. These values were mainly related to the high or medium sensitivity of the variables slope, soil thickness and depth of water level in much of the study area. It is concluded that the methodology of environmental sensitivity to oil for terrestrial areas, specifically for the road modal, was adequate when determining the environments with greater and lesser sensitivity, however the parameters of analysis should be adjusted according to the local reality of the environments. In addition, the use of geotechnical tools proved effective, making this methodology accessible for future studies.
714

Investigation on uncertainty and sensitivity analysis of complex systems / Enquête sur l'incertitude et l'analyse de sensibilité des systèmes complexes

Zhu, Yueying 23 October 2017 (has links)
Par un développement en série de Taylor, une relation analytique générale est établie pour calculer l’incertitude de la réponse du modèle, en assumant l'indépendance des entrées. En utilisant des relations de puissances et exponentielles, il est démontré que l’approximation souvent utilisée permet d’évaluer de manière satisfaisante l’incertitude sur la réponse du modèle pourvu que l’incertitude d’entrée soit négligeable ou que le modèle soit presque linéaire. La méthode est appliquée à l’étude d’un réseau de distribution électrique et à un modèle d’ordre économique.La méthode est étendue aux cas où les variables d’entrée sont corrélées. Avec la méthode généralisée, on peux déterminer si les corrélations d'entrée doivent ou non être considérées pour des applications pratiques. Des exemples numériques montrent l'efficacité et la validation de notre méthode dans l'analyse des modèles tant généraux que spécifiques tels que le modèle déterministe du VIH. La méthode est ensuite comparée à celle de Sobol. Les résultats montrent que la méthode de Sobol peut surévaluer l’incidence des divers facteurs, mais sous-estimer ceux de leurs interactions dans le cas d’interactions non linéaires entre les paramètres d’entrée. Une modification est alors introduite, aidant à comprendre la différence entre notre méthode et celle de Sobol. Enfin, un modèle numérique est établi dans le cas d’un jeu virtuel prenant en compte la formation de la dynamique de l'opinion publique. L’analyse théorique à l’aide de la méthode de modification d'un paramètre à la fois. La méthode basée sur l'échantillonnage fournit une analyse globale de l'incertitude et de la sensibilité des observations. / By means of taylor series expansion, a general analytic formula is derived to characterise the uncertaintypropagation from input variables to the model response,in assuming input independence. By using power-lawand exponential functions, it is shown that the widelyused approximation considering only the first ordercontribution of input uncertainty is sufficiently good onlywhen the input uncertainty is negligible or the underlyingmodel is almost linear. This method is then applied to apower grid system and the eoq model.The method is also extended to correlated case. Withthe extended method, it is straightforward to identify theimportance of input correlations in the model response.This allows one to determine whether or not the inputcorrelations should be considered in practicalapplications. Numerical examples suggest theeffectiveness and validation of our method for generalmodels, as well as specific ones such as thedeterministic hiv model.The method is then compared to Sobol’s one which isimplemented with sampling based strategy. Resultsshow that, compared to our method, it may overvaluethe roles of individual input factors but underestimatethose of their interaction effects when there arenonlinear coupling terms of input factors. A modificationis then introduced, helping understand the differencebetween our method and Sobol’s one.Finally, a numerical model is designed based on avirtual gambling mechanism, regarding the formation ofopinion dynamics. Theoretical analysis is proposed bythe use of one-at-a-time method. Sampling-basedmethod provides a global analysis of output uncertaintyand sensitivity.
715

An exploration of parental sensitivity and child cognitive and behavioral development.

Ingle, Sarah J. 08 1900 (has links)
The current study attempted to show the relationship of paternal sensitivity and maternal sensitivity and their possible influences on child cognitive and behavioral development. This study used data collected as part of the National Institute for Child Health and Human Development (NICHD) Study of Early Child Care, which is a longitudinal, multi-site study. Correlation and regression analyses were computed to examine relationships between the variables at child age 6 and 36 months. Results indicated paternal sensitivity was a significant positive predictor of child cognitive abilities and a negative predictor of both fathers' reports of children's externalizing and internalizing behaviors. Maternal sensitivity was a significant negative predictor of mothers' reports of children's externalizing behaviors. Interpretations of these results and directions for future research are discussed.
716

Global sensitivity analysis on vibro-acoustic composite materials with parametric dependency / L'analyse de sensibilité globale sur matériaux composites vibroacoustiques avec la dépendance paramétrique

Chai, Wenqi 30 November 2018 (has links)
Avec le développement rapide des modèles mathématiques et des outils de simulation, le besoin des processus de quantification des incertitudes a été bien augmenté. L'incertitude paramétrique et la groupe des nombreux décisions sont aujourd’hui les deux barrières principales dans la résolution des grandes problèmes systématiques.Capable de proportionner l'incertitude de la sortie sur celle des entrées, l’Analyse de Sensibilité Globale (GSA) est une solution fiable pour la quantification de l’incertitude. Parmi plusieurs algorithmes de GSA, Fourier Amplitude Sensitivity Analysis (FAST) est l’un des choix les plus populaires des chercheurs. Basé sur ANOVA-HDMR (ANalysis Of VAriance - High Dimensional Model Representation), il est solide en mathématique est efficace en calcul.Malheureusement, la décomposition unique d’ANOVA-HDMR se dépend sur l’indépendance des entrées. À cause de cela, il y a pas mal de cas industriels qui ne peut pas se traiter par FAST, particulièrement pour ceux qui donnent uniquement les échantillons mais sans lois de distribution. Sous cette demande, deux méthode extensifs de FAST avec design de corrélation sont proposées et étudiées dans la recherche. Parmi les deux méthodes, FAST-c s’est basé sur les distributions et FAST-orig s’est basé sur les échantillons.Comme applications et validations, multiples problèmes vibroacoustiques se sont traités dans la recherche. Les matériaux acoustiques avec soustructures, sont des candidats parfaits pour tester FAST-c et FAST-orig. Deux application sont présentées dans la première partie de la thèse, après l’état de l’arts. Les modèles choisis sont matérial poroélastique et structures composite sandwich, dont les propriétés mécaniques sont tous fortement influencées par les paramètres géométriques microscopique ou mesoscopique. D’avoir la méthode de FAST originale comparée avec les deux nouvelles, on trouve bien plus d’information sur la performance vibroacoustique de ces matériaux.Déjà répondu à la demande de GSA sur les modèles avecs les variables dépendantes, la deuxième partie de la thèse contient plus de recherches reliées avec FAST. D’abord FAST est pris en comparaison avec Random Forest, une algorithme bien connu de data-mining. Leurs erreurs potentiels et la possibilité de fonctioner ensemble sont discutés. Et dans les chapitres suivies, plus d’application de FAST sont présentées. Les méthodes sont appliquées sous plusieurs différente conditions. Une modèle de structure périodique qui contient des corrélation parmi les unités nous a en plus forcé à développer une nouvelle FAST-pe méthode. Dans ces applications, les designs des processus préliminaires et les stratégies d’échantillonages sont des essences à présenter. / With rapid development of mathematical models and simulation tools, the need of uncertainty quantification process has grown higher than ever before. Parametric uncertainties and overall decision stacks are nowadays the two main barriers in solving large scale systematic problem.Global Sensitivity Analysis (GSA) is one reliable solution for uncertainty quantification which is capable to assess the uncertainty of model output on its inputs’. Among several GSA algorithms, Fourier Amplitude Sensitivity Test (FAST) is one of the most popular choices of researchers. Based on ANOVA-HDMR (ANalysis Of VAriance - High Dimensional Model Representation), it is both mathematically solid and computationally efficient.One unfortunate fact is that the uniqueness of ANOVA-HDMR relies on the independency of input variables. It makes FAST unable to treat many industrial cases especially for those with only datasets but not distribution functions to be found. To answer the needs, two extended FAST methods with correlation design are proposed and further studied in this research. Among them FAST-c is distribution-based and FAST-orig is data-based.As a frame of validation and application, a number of vibroacoustic problems are dealt with in this research. Vibroacoustic materials with substructures, are perfect test candidates for FAST-c and FAST-orig. Two application cases are presented in the first part of this thesis, following the literature review. The models chosen here are poroelastic material and sandwich composite structures, both having their mechanical properties hugely influenced by their microscopic and mesoscopic geometric parameters. Getting the original FAST method compared to the two with correlation design, many different features on materials’ vibroacoustic performance are latter discovered.Having got an answer for GSA on models with dependent variables, the second part of this thesis contains more extended researches related to FAST. It is taken into comparison with Random Forest, a well-known data-mining algorithm. The potential error of both algorithms are analyzed and the possibility of joint application is discussed. In the following chapters, more applications of FAST-series methods are reported. They are applied under various conditions where another improved version named FAST-pe is developed to treat a model of periodic structures with correlation among each units. Upon these FAST application cases, the design of preliminary process and the sampling strategies is the core part to be introduced.
717

Quantitative assessment of foot sensitivity: The effects of foot sole skin temperature, blood flow at the foot area and footwear

Schlee, Günther 30 August 2010 (has links)
The human foot has been accepted over the years as an important source of afferent input, used not only in the recognition of the surrounding environment (e.g. hard and soft surfaces), but also in the fine regulation of common daily-live movements (e.g. gait and balance control). The performance of these movements is usually accompanied by fluctuations in foot skin temperature as well as reciprocal blood flow changes at the foot area. Moreover, both variables are likely to be affected by footwear usage. Although these three factors are constantly present during the performance of daily live movements, only little and partially controversial information regarding the effects of foot skin temperature, blood flow at the foot area and footwear on foot sensitivity can be found in the literature. Therefore, the goal of the thesis was to investigate the effects of foot skin temperature, blood flow at the foot area and footwear on plantar foot vibration sensitivity of healthy young subjects. Three single studies were performed in order to investigate each variable separately. The first study investigated the influence of foot sole skin temperature on plantar foot sensitivity of 40 healthy subjects. Vibration thresholds were measured at 200Hz at a initial baseline temperature and after cooling/warming the foot skin 5-6 °C. The second study investigated the influence of short-time lower leg ischemia on plantar foot vibration sensitivity of 39 young adults. Lower leg ischemia was evoked with a pneumatic tourniquet, placed about 10cm above the popliteus cavity. Vibration thresholds were measured at 200 Hz in three different cuff pressure conditions: baseline (0 mmHg), low (50 mmHg) and high (150 mmHg). Finally, the influence of footwear on foot sensitivity was investigated in the third study, using specific Formula 1 shoes. Twenty-five male subjects participated in the study. Plantar foot vibration thresholds were measured at 30 and 200 Hz in five different foot/shoe conditions (barefoot and four shoe conditions). In all studies, vibration thresholds were measured at three anatomical locations of the plantar foot: heel, first metatarsal head (MET I) and hallux. The main results of the three studies show that the analysed variables significantly influence plantar foot vibration sensitivity. Data from the first study show that 5-6 °C alterations in foot skin temperature significantly influence the foot sensitivity of healthy young adults, whereby skin cooling results in reduced foot sensitivity, whereas skin warming improves plantar foot vibration sensitivity. The results of the second study indicate that short-time lower leg ischemia; especially regarding the high cuff pressure condition (150 mmhg), significantly reduces plantar foot sensitivity. Data from the third study show that the footwear effects on foot sensitivity are frequency-dependent. While barefoot sensitivity is better than shod sensitivity at 30Hz, shod sensitivity is better than barefoot sensitivity when measured at 200Hz. In conclusion, foot sole skin temperature, blood flow at the foot area and footwear significantly influence the plantar foot vibration sensitivity of healthy young adults. The alterations in foot sensitivity caused by these variables have important consequences for future clinical as well as movement-related research. Future clinical applications of quantitative sensory testing should consider the influence of these three factors during the assessment of sensory data, in order to standardize the measurement procedures as well as to enhance the quality of the collected data. Regarding the movement-related research, further studies should try to identify the importance of foot sensitivity for the performance of different types of movements (including sport-related activities). Additionally, the combined effects of movement-related changes in foot skin temperature and blood flow should be analysed and integrated in the development process of functional footwear, which is able to fulffill the foot sensitivity requirements of different movements. / Die Rolle des menschlichen Fußes als wichtiger „Mediator“ sensorischer Reize wird zunehmen in der Literatur akzeptiert. Die vom Fuß aufgenommenen afferenten Informationen werden im Zentralen Nervensystem integriert und weitergeleitet, um die Regulation typischer Bewegungsmuster (z.B. Gang und Gleichgewichtskontrolle) mitzusteuern. Während der Durchführung derartiger Bewegungen werden oftmals Änderungen der Hauttemperatur oder auch des Blutflusses im Fußbereich provoziert. Diese werden wiederum durch das Tragen von Schuhen beeinflusst. Obwohl Hauttemperatur, Blutfluss im Fußbereich und Schuhwerk wichtige Faktoren bei der Bewegungsdurchführung darstellen, können nur wenige und teilweise konträre Informationen über den Einfluss dieser Faktoren auf die Fußsensibilität in der Literatur gefunden werden. Somit hat diese Dissertation zum Ziel, den Einfluss der Temperatur der Fußsohle, des Blutflusses am Fußbereich sowie des Schuhwerkes auf die Vibrationssensibilität des plantaren Fußes gesunder Probanden zu untersuchen. Um den Einfluss der einzelnen Parameter auf die Fußsensibilität untersuchen zu können, wurden drei Studien durchgeführt. Die erste Studie hatte zum Ziel, den Einfluss der Temperatur der Fußsohle auf die Vibrationssensibilität von 40 Probanden zu untersuchen. Dabei wurden die Vibrationsschwellen, - mit einer Frequenz von 200 Hz -, bei einer Ausgangsmessung sowie nach einer 5-6 °C Abkühlung/Erwärmung der Haut der Fußsohle gemessen. In der zweiten Studie wurde der Einfluss einer Kurzzeitischämie des Unterschenkels auf die plantare Fußsensibilität von 39 Probanden getestet. Die Ischämie im Unterschenkel wurde mit Hilfe eines im Bereich der fossa popliteal platzierten pneumatischen Tourniquets hervorgerufen. Die plantaren Vibrationsschwellen wurden mit einer Frequenz von 200Hz in drei verschiedenen Druckbedingungen ermittelt: Ausgang (0 mmHg), niedrig (50 mmHg) und hoch (150 mmHg). Schließlich beschäftigt sich die dritte Studie mit dem Einfluss vom Schuhwerk auf die Fußsensibilität. Fünfundzwanzig Probanden haben an der Studie teilgenommen. Die Vibrationsschwellen wurden mit Frequenzen von 30 und 200 Hz bei fünf verschiedenen Bedingungen gemessen (eine Barfuss- und vier Schuhbedingungen). In allen Studien wurden die Vibrationsschwellen im plantaren Fußbereich unter der Ferse, dem Metatarsalkopf I sowie unter dem Hallux ermittelt. Die Ergebnisse der drei Studien zeigen, dass die analysierten Parameter einen signifikanten Einfluss auf die plantare Vibrationssensibilität der Probanden haben. Die erste Studie zeigt, dass eine 5-6° C - Schwankung der Hauttemperatur der Fußsohle die Fußsensibilität signifikant beeinflusst, wobei die Erwärmung der Haut eine Zunahme der Fußsensibilität verursacht und die Abkühlung eine Abnahme der Fußsensibilität hervorruft. Die Ergebnisse der zweiten Studie demonstrieren, dass die im Unterschenkel hervorgerufene Ischämie eine Verschlechterung der Fußsensibilität verursacht, insbesondere bei den Messungen der Hochdruckbedingung (150 mmHG). Die Daten der dritten Studie weisen darauf hin, dass der Einfluss vom Schuhwerk auf die Vibrationssensibilität des plantaren Fußes frequenzabhängig ist. Bei einer Vibrationsfrequenz von 30Hz ist die Sensibilität barfuss besser als die mit Schuhen gemessene Vibrationssensibilität. Hingegen ist bei einer Frequenz von 200 Hz die mit Schuhen gemessenen Sensibilität besser als die Sensibilität barfuss. Anhand der Ergebnisse der drei Studien konnte festgestellt werden, dass die Temperatur der Fußsohle, Blutfluss im Fußbereich und Schuhwerk einen signifikanten Einfluss auf die plantare Vibrationssensibilität gesunder Probanden haben. Daraus folgen wichtige Hinweise für zukünftige klinische- sowie bewegungsorientierte Forschung. Der Einfluss der drei analysierten Parameter sollte künftig bei der Beurteilung sensorischer Daten mit einbezogen werden. Dies würde zum einem eine Standardisierung der Messverfahren gewährleisten, zum anderen die Qualität der im klinischen Bereich gemessenen Daten erhöhen. Im Rahmen bewegungsorientierter Forschung soll die Wichtigkeit der Fußsensibilität bei der Durchführung unterschiedlicher Bewegungsformen, auch sportlicher Bewegung, näher untersucht werden. Weiterhin sollte eine gemeinsame Analyse der bewegungsbezogenen Änderungen der Hauttemperatur bzw. des Blutflusses im Fußbereich in künftiger Forschung angestrebt werden. Folglich können diese Änderungen in die Entwicklung funktionellen Schuhwerkes eingesetzt werden, um den Anforderungen der Fußsensibilität bei unterschiedlichen Bewegungsformen möglichst gerecht zu werden.
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Coil Sensitivity Estimation and Intensity Normalisation for Magnetic Resonance Imaging / Spolkänslighetsbestämning och intensitetsnormalisering för magnetresonanstomografi

Herterich, Rebecka, Sumarokova, Anna January 2019 (has links)
The quest for improved efficiency in magnetic resonance imaging has motivated the development of strategies like parallel imaging where arrays of multiple receiver coils are operated simultaneously in parallel. The objective of this project was to find an estimation of phased-array coil sensitivity profiles of magnetic resonance images of the human body. These sensitivity maps can then be used to perform an intensity inhomogeneity correction of the images. Through investigative work in Matlab, a script was developed that uses data embedded in raw data from a magnetic resonance scan, to generate coil sensitivities for each voxel of the volume of interest and recalculate them to two-dimensional sensitivity maps of the corresponding diagnostic images. The resulting mapped sensitivity profiles can be used in Sensitivity Encoding where a more exact solution can be obtained using the carefully estimated sensitivity maps of the images. / Inom magnetresonanstomografi eftersträvas förbättrad effektivitet, villket bidragit till utvecklingen av strategier som parallell imaging, där arrayer av flera mottagarspolar andvänds samtidigt. Syftet med detta projekt var att uppskattamottagarspolarnas känslighetskarta för att utnyttja dem till i metoder inom magnetresonansavbildning. Dessa känslighetskartor kan användas för att utföra intensitetsinhomogenitetskorrigering av bilderna. Genom utforskande arbete i Matlab utvecklades ett skript som tillämpar inbyggd rådata, från en magnetiskresonansavbildning för att generera spolens känslighet för varje voxel av volymen och omberäkna dem till tvådimensionella känslighetskartor av motsvarande diagnostiska bilder. De resulterande kartlagda känslighetsprofilerna kan användas i känslighetskodning, där en mer exakt lösning kan erhållas med hjälp av de noggrant uppskattade känslighetskartorna.
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Development of a current to pressure (I/P) converter. System analysis of a current to pressure (I/P) converter through physical modelling and experimental investigation, leading to a design for improved linearity and temperature independence.

Saneecharaun, Jeet T. January 2014 (has links)
Current-to-pressure (I/P) converters are pneumatic devices which provide precise control of pressure in various industries – for example these devices are often used in valve positioner systems (typically found in the oil and gas industry) and tensioning systems (typically used in the packaging industry). With an increasing demand for such devices to operate in harsh environments all by delivering acceptable performance means that Current-to-pressure converters need to be carefully designed such that environmental factors have no or minimal effects on its performance. This work presents an investigation of the principles of operation of an existing I/P converter through mathematical modelling. A simulation model has been created and which allows prediction of performance of the I/P converter. This tool has been used to identify areas of poor performances through theoretical analysis and consequently led to optimisation of certain areas of the I/P converter through a design change to deliver improved performances, for instance the average percentage shift in gain at 1mA input signal (over the temperature range of -40°C to 85°C) on the new I/P converter is 2.13% compared to the average gain of 4.24% on the existing I/P converter, which represents an improvement of almost two fold. Experimental tests on prototypes have been carried out and tests results showed that improved linearity and temperature sensitivity can be expected from the new design.
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Central Visual Field Sensitivity Data from Microperimetry with Spatially Dense Sampling

Astle, A.T., Ali, I., Denniss, Jonathan 04 August 2016 (has links)
Yes / Microperimetry, also referred to as fundus perimetry or fundus-driven perimetry, enables simultaneous acquisition of visual sensitivity and eye movement data. We present sensitivity data collected from 60 participants with normal vision using gaze-contingent perimetry. A custom designed spatially dense test grid was used to collect data across the visual field within 13° of fixation. These data are supplemental to a study in which we demonstrated a spatial interpolation method that facilitates comparison of acquired data from any set of spatial locations to normative data and thus screening of individuals with both normal and non-foveal fixation (Denniss and Astle, 2016)[1].

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