Made available in DSpace on 2016-12-06T17:07:26Z (GMT). No. of bitstreams: 1 Dissertao_verso final.pdf: 1687379 bytes, checksum: e0fdde3c9254031a3b1d1b01a860c93d (MD5) Previous issue date: 2010-12-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The decrease in knee flexion in swing phase present in chronic stroke individuals contributes to the decrease in gait velocity found in this population. With the association of backward walk to sensory stimulation through the electro-stimulation (FES) in the hamstrings, it is believed there may be an increase in knee flexion during walking back and that these benefits are transferred to move forward. The objective was to evaluate the immediate results in forward walking (FW) after a short backward walking (BW) training on a treadmill combined with electro stimulation (EE) in the knee flexors. The kinematics of ten individuals (54.4 ± 14.7 years) with chronic hemiparesis (51.8 ± 49.8 months) was performed with 30 Hz cameras with bullets while walking on a treadmill in three conditions in the BW (Pre-T: before training, EE : During the ride back with FES and Post-T: 10 minutes after training and without FES) and two conditions of FW (Pre-F: pre-training and post-F: after the training). The intervention was BW performed for 20 minutes on the treadmill at comfortable speed associated with EE in the knee flexors in the swing phase triggered by a sensor placed on the insole. The Kinematics variables analyzed were the step length, stance and swing phase duration, and angular variables of knee and hip. BW were analyzed by repeated measures ANOVA and FW by test t. Intra limb coordination was analyzed by quantifying the angle angle diagram through the correlation coefficient (ACC) of the vector coding technique. In the BW, the training increased the peak value of flexion during EE (p = 0.01) which remained after 10 min of rest without the FES (p = 0.02). In FW, there was increased peak knee flexion (p = 0.005) and range of hip flexion (p = 0.003). Five of the ten participants improved the coordination pattern of increasing the value of ACC but were not significant. The results indicate that the association between treadmill backward walking and electric stimulation may be an effective method to improve the gait pattern in subjects with hemiparesis. The effects of a training of longer duration and effect of this improvement in the locomotor pattern in the soil must still be evaluated / A diminuição da flexão do joelho na fase de balanço presente em pessoas com seqüela de Acidente Vascular Encefálico (AVE) contribui para a diminuição da velocidade da marcha encontrada nesta população. Com a associação do andar para trás com estímulos sensoriais, através da eletro estimulação (FES) nos isquiotibiais, acredita-se que possa ocorrer um aumento da flexão de joelho durante o andar para trás e que esses benefícios sejam transferidos para o andar para frente .Objetivou-se avaliar os resultados imediatos no andar para frente (AF) de um curto treino no andar para trás (AT) em esteira combinado a eletro estimulação (EE) nos flexores do joelho. A cinemática de dez indivíduos (54,4±14,7 anos) com hemiparesia crônica (51,8±49,8 meses) foi realizada com câmeras de 30 Hz com marcadores durante a caminhada em esteira em 3 condições no AT (Pré-AT: antes do treino, EE: durante o andar para trás com FES e Pós-AT: 10 minutos após o treino e sem FES) e 2 condições de AF (Pré AF: antes do treino e Pós-AF: após o término do treino). A intervenção foi AT por 20 minutos na esteira em velocidade confortável associada à EE nos flexores de joelho disparada na fase de balanço através de um sensor colocado na palmilha. As variáveis cinemáticas analisadas foram comprimento do passo, duração do apoio e do balance, e variáveis angulares de quadril e joelho. No AT foram analisadas pela ANOVA medidas repetidas e do AF através de teste t. A coordenação intra membro foi analisada pela quantificação do diagrama ângulo ângulo através do coeficiente de correlação (ACC) da técnica vector coding. No AT, o treino aumentou o valor de pico de flexão durante a EE (p=0,01) que se manteve após 10 min de repouso sem o FES (p=0,02). No AF, observou-se o aumento do pico de flexão do joelho (p=0,005) e da amplitude de flexão do quadril (p=0,003). Cinco entre os dez participantes melhorou o padrão de coordenação aumentando o valor do ACC, porém não foi significativo. Os resultados indicam que a associação entre esteira, andar para trás e FES pode ser um método eficaz para melhora do padrão de marcha em indivíduos com hemiparesia. Os efeitos de um treinamento de maior duração e o efeito deste na melhora do padrão locomotor em solo ainda devem ser avaliados

It is believed that a large number of people experience remaining symptoms after COVID-19, so-called post-COVID. The formal definition and diagnostic criteria of post-COVID have been a scientific controversy. So far, there is no reliable system for distinguishing the severity of post-COVID. This type of measurement would be helpful in future targeted therapies. Therefore, this thesis aims to evaluate the relationship between an individual’s functional status today and the symptoms present as well as identify relevant groups of post-COVID based on these 17 long-term symptoms of post-COVID. Further, to produce a model for which of these groups an individual belongs to. By using cluster analysis and ordinal logistic regression, Post-COVID Syndrome scores are produced. That is based upon both subjects who were hospitalised and those who were not, collected through a project called COMBAT post-covid. The individuals are then divided into groups based on these scores, and a prediction model is made using ordinal logistic regression and backward deletion. Three well-separated groups of post-COVID are found based on the produced scores. The prediction model indicates that the nine variables Sex, BMI, Smoking, Snuff, Heart disease, Lung disease, Diabetes, Chronic pain and Symptom severity at the onset seem important for predicting someone’s group. This study showed that the remaining symptoms affected an individual’s functional status, including self-reported working ability and general health.

Proliferation of non-linear, single-phase power electronics loads, such as personal computers, television sets, CFLs, has resulted in thousands of individual small harmonic current injectors connected to a distribution feeder network. Harmonic standard: IEC 1000-3-2 classifies such loads as Class D, “low-voltage” equipment with current emissions limited to 16A/Phase. Individual harmonic contributions of such loads appear insignificant; their collective contribution, however, is a matter of concern. The average order of voltage distortion usually varies between 4-6%; current distortion, however, is usually of the order of 100%. Limitations and high-costs associated with conventional harmonic mitigation measures, has furthered the need for regulation and alternative strategies. The objective of this research is to predict, and mitigate the effects of harmonic proliferation in the main supply current measured at the point of common coupling (PCC). An equivalent circuit model – an aggregation of single phase power electronics loads connected to the distribution feeder network is proposed as a part of a forward solution. Each load, individually, behaves as a harmonic current source; the proposed model combines these individual harmonic current injectors into a single harmonic source connected at the PCC and their collective contribution as a single composite harmonic signal. It represents harmonic conditions at the PCC and provides a theoretical measure of harmonic distortion in the supply current. Such a model finds application during harmonic compliance testing for single-phase power electronics loads; it simulates and predicts the harmonic response of such loads using a theoretical pure 60 Hz sine wave as the supply voltage diffcult to obtain physically, yet critical to such tests. The accuracy of the equivalent circuit model in predicting a harmonic response is pivotal to a successful forward solution. A feed-backwards mechanism is proposed. For a given harmonic supply voltage and circuit configuration of the equivalent circuit model, the feed-backwards method generates the modeled response and compares it to a reference physical response. Finally, it optimizes the circuit configuration to a unique Correction Factor that facilitates an accurate modeled response. Three optimization algorithms, labeled as Response Optimization algorithms have been developed to execute the feed-backwards mechanism. These algorithms are written in FORTRAN-90. / text

The migration of signing algorithms is a process which can be used to move from signing algorithms which are regarded as less safe to algorithms which are regarded as safer. The safety of cryptographic algorithms has been compromised before, algorithms such as SHA-1 has been proven to be broken. The goal of this study was to find criteria that could define a successful migration as well as evaluating a method to perform a migration. The criteria were found by evaluating related works found in an RFC document as well as in a Springer conference paper. The criteria that was found was the following: backwards compatibility, no downtime, no need for mass revocation, no need for strict scheduling and no extra overhead. The evaluated method utilized a construct called a multiple key certificate; it was chosen because it conformed to most of the found criteria. The multiple key certificate utilized two different key pairs, one generated from a conventional algorithm and the other using an alternative algorithm, it also conformed to the x.509 standard. The alternative algorithm could be chosen to be a post quantum algorithm. The prototype was tested for time overhead, memory overhead and backward compatibility. The results of testing to sign and verify 10 000 certificates as well as examining the file size of the certificate showed that the choice of alternative algorithm heavily affects the time overhead of the prototype certificate. The multiple key certificate also proved to be backwards compatible with widely used applications. This solution has proven itself to act in accordance to all the newly established criterion except for the criterion regarding overhead however, alternative algorithms could be strategically chosen to minimize overhead. The multiple key certificate seems to be a successful way to migrate signing algorithms. / Migration av signeringsalgoritmer som används i certifikat är en process som kan behövas när en signeringsalgoritm som är mindre säker ska ersättas med en som är mer säker. Säkerheten som återfinns hos kryptografiska algoritmer har brutits förut, algoritmer såsom SHA-1 har bevisats vara osäkra. Målet med denna studie var att ta fram kriterier som kan definiera en lyckad migration samt evaluera en metod som kan användas för att utföra en migration. Kriterierna togs fram genom att studera tidigare arbeten inom migration av signeringsalgoritmer, dessa arbeten återfinns hos RFC dokument samt konferensrapporter från Springer. Kriterierna som togs fram var följande: kompatibilitet med äldre system, ingen nertid, inget behov av massrevokering, inget behov av strikta tidsscheman samt ingen extra omkostnad. Metoden som utvärderades kallas för flernyckels certifikat. Den valdes för att den följde flest av de nyfunna kriterierna. Lösningen utnyttjar två olika nyckelpar, nämligen ett nyckelpar som har genererats med en konventionell algoritm samt ett nyckelpar som har genererats med en alternativ algoritm. Lösningen följer även x.509 standarden. Den alternativa algoritmen kan väljas så att den är postkvantum. Prototypen testades för omkostnad i tid samt minne genom att signera och verifiera 10 000 certifikat samt att titta på certifikatens filstorlek. Prototypen testades även för kompatibilitet med kända applikationer. Resultaten visade att valet av alternativa algoritmer hade stor påverkan på omkostnaderna. Tester visade att prototypen var kompatibel med applikationer som används i stor utsträckning. Lösningen verkade följa alla nyfunna kriterier förutom kriteriet angående omkostnad men den alternativa algoritmen kan strategiskt väljas för att minimera omkostnaden. Prototypen verkar vara ett lyckat sätt att migrera signeringsalgoritmer.

<p> Skilled trades are in demand across many industries and many countries. Skilled trades refer to occupations that require training and proficiency in a specialized field, such as weld?ing, carpentry, or mechanics. The challenge is upskilling workers to become suited for these positions. One way training might be made more accessible is through low cost VR applica?tions as they can provide a ’learn by doing’ modality that is effective for learning motor skills, and also engaging for providing a holistic training experience. In this thesis, design guide?lines and a methodology for creating training programs that target hand tool based skills are laid out, tested, and refined for future usage. Working with content experts, a learning plan was developed via the backward design methodology, evaluated in a user study, and then applied to a second use case. The results of the user study showed that those who trained with VR were able to perform the prescribed task more quickly and with less mistakes. The implication of the second use case is that the established guidelines are versatile enough to be applied to other industries and simple enough to adapt industry specific knowledge to. The hope is that this work can help bridge the gap between the theoretical possibilities of VR training, effective training methodology, and real world application. </p>

Outreach is a small, but significant component to modern research. Developing an exhibit for public display can be an effective way to communicate science to broad audiences, although it may be a less familiar method to scientists than writing papers or giving presentations. I outline the process of developing an interactive exhibit for outreach, and evaluate and discuss the effectiveness of a computer exhibit designed to communicate estuary currents and scientific modeling using Olympia Oyster restoration in the Yaquina Bay estuary as a theme. I summarize the results of this project in three primary recommendations: 1) exhibit developers should be deliberate in the decision to use a computer and only select this media if it is determined to be the best for communicating exhibit learning outcomes, 2) the design of visualizations to convey research results should be carefully modified from their scientific forms to best meet the exhibit learning outcomes and expectations of the exhibit audience, and 3) scientists should play an integral role in the development of scientific content-based exhibits, but their expertise, and the range of expertise from other members of the exhibit development team, should be strategically utilized. / Graduation date: 2012