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Dizziness is a common, multifactorial problem that causes reductions in quality of life and is a major risk factor for falls, but the role of vision is a very under-researched area. This study aimed to investigate any link between dizziness and vision and to establish if changes in spectacle lens correction could elicit dizziness symptoms. A link between dizziness and self-reported poor vision was indicated in the epidemiological literature as shown by a systematic review, provided lightheadedness was not included in the definition of dizziness. Cases of individuals who reported vision-related dizziness were investigated to determine potential areas of research for this thesis and subsequently two studies investigated the effects of refractive correction changes on dizziness status. The first study was limited by logistical problems, although it highlighted limitations in the short form of the Dizziness Handicap Inventory that was used to quantify dizziness. Results of an optometry practice recheck study found that oblique cylindrical changes were significantly more likely to be associated with dizziness symptoms than other spectacle lens changes. It also highlighted that optometrists do not ask/record about dizziness symptoms with only 4% of records including “dizziness” as a problem when 38% of patients reported dizziness symptoms when directly asked. All studies highlighted a need for a patient-reported outcome measure to be designed to assess vision-related dizziness. Literature review, interviews with experts and patients and focus groups led to the development of a pilot questionnaire and subsequently a 25-item Vision-Related Dizziness instrument, the VRD-25. This was validated using responses from 223 respondents, with 79 participants completing the questionnaire a second time to provide test-retest data. Two subscales of VRD-12-frequency (VRD-12f) and VRD-13-severity (VRD-13s) were shown to be unidimensional and had good psychometric properties, convergent validity and test-retest repeatability. The VRD-25 is the only patient-reported outcome measure developed to date to assess vision related dizziness and will hopefully provide the platform to further grow this under-researched area that seems likely to provide important clinical information. / College of Optometrists sponsored the research with a Postgraduate Research Scholarship

Purpose: To determine whether symptoms of dizziness and fall rates change due to routine cataract surgery and to determine the influence of visual and refractive factors on these common problems in older adults. Methods: Self-reported dizziness and falls were determined in 287 subjects (mean age of 76.5±6.3 years, 55% females) before and after routine cataract surgery for the first (81, 28%), second (109, 38%) and both eyes (97, 34%). Six-month falls rates were determined using self-reported retrospective data. Dizziness was determined using the short-form of the Dizziness Handicap Inventory. Results: The number of patients with dizziness reduced significantly after cataract surgery (52% vs. 38%; χ2 = 19.14 , p<0.001), but the reduction in number of patients who fell in the 6-months post surgery was not significant (23% vs. 20%; χ2= 0.87, p=0.35). Multivariate logistic regression analyses found significant links between post-operative falls and change in spectacle type (increased risk if switched into multifocal spectacles). Post-operative dizziness was associated with changes in best eye visual acuity and changes in oblique astigmatic correction. Conclusions: Dizziness is significantly reduced by cataract surgery and this is linked with improvements in best eye visual acuity, although changes in oblique astigmatic correction increased dizziness. The lack of improvement in falls rate may be associated with switching into multifocal spectacle wear after surgery. / The Dunhill Medical Trust

Vibration analysis is a method that studies patterns in vibration data and measures vibration levels. It is usually performed on time waveforms of the vibration signal directly and on thefrequency spectrum derived by applying the Fourier Transform on the time waveform. Conventional vibration analysis methods are either expensive, need a complicated setup, or both. Non-contact measurement systems, such as high-speed cameras coupled with computer vision and motion magnification methods, are suitable options for monitoring vibrations of any system. In this work, many classic and state-of-the-art computer vision tracking algorithms were compared. Low and high frame rate videos are used to evaluate their ability to track the oscillatory movement that characterizes vibrations. The trackers are benchmarked with literature and experimental study. Two sets of experiments were carried out in this work, one using a cantilever and another using a robot. The resonance frequencies obtained from the vision camera method are compared to the Laser vibrometer method, which is industry standard. The results show that the resonance frequencies of both methods are closer to each other. The limitations of the tracking algorithm-based approach used for vibration analysis were discussed at the end. Since the methods provided are generic, they may be easily modified for other relevant applications. / Vibrationsanalys är en metod som studerar mönster i vibrationsdata och mäter vibrationsnivåer. Det utförs vanligtvis på tidvågformer av vibrationssignalen direkt och på frekvensen, spektrum som härleds genom att applicera Fourier Transform på tidvågform. Konventionella vibrationsanalysmetoder är antingen dyra, kräver en komplicerad installation eller båda. Beröringsfria mätsystem, till exempel höghastighetskameror i kombination med datorsyn och rörelseförstoringsmetoder, är lämpliga alternativ för att övervaka vibrationer i alla system. I detta arbete jämfördes många klassiska och toppmoderna datorsynsspårningsalgoritmer. Videor med låg och hög bildhastighet används för att utvärdera deras förmåga att spåra den oscillerande rörelsen som kännetecknar vibrationer. Spårarna jämförs med litteratur och experimentell studie. I detta arbete utfördes två uppsättningar experiment, ett med en fribärare och ett annat med en robot. De resonans frekvenser som erhålls från visionkamerametoden jämförs med Laservibrometer metoden, som är branschstandard. Resultaten visar att resonansfrekvenserna för båda metoderna ligger närmare varandra. Begränsningarna av det spårningsalgoritmbaserade tillvägagångssättet som används för vibrationsanalys diskuterades i slutet. Eftersom de angivna metoderna är generiska kan de enkelt modifieras för andra relevanta applikationer.

A partir da constatação do limitado investimento no design de produtos de auxílio à visão subnormal no Brasil e de sua crescente demanda, esta tese teve por objetivo analisar o estado da arte dos produtos existentes no mundo, particularmente dos que oferecem ampliação eletrônica da imagem, propor um projeto de equipamento inovador que agrega videomagnificação a uma prancha de leitura, e analisar alguns casos pioneiros de design para a saúde no Brasil, inclusive oftalmológico. Como método foram realizadas entrevistas, pesquisas bibliográficas, por internet e observação de pacientes para embasar a proposta de projeto de prancha de leitura acoplada a câmera de videomagnificação para deficientes visuais. A proposta resultante tem como base comum o produto prancha de leitura acoplada a lupa já disponível no mercado em que no lugar da lupa será colocada uma câmera de vídeomagnificação para leitura de perto. Nesta prancha de base o usuário poderá ler de modo estável comandando por sua mão o movimento do anel em volta da câmera que por sua vez excursionará horizontalmente num trilho para manter a linha e o foco de leitura constantes. Evidenciam-se os elementos indicadores de que o design inovador deste equipamento apresenta vantagens em relação aos equipamentos atualmente existentes e que poderão contribuir para facilitar a leitura dos portadores de baixa visão. Por meio do design com responsabilidade social, este trabalho pretende dar uma contribuição para a inclusão do deficiente visual no Brasil. / Low investment in design for low vision and growing demand for low vision products in Brazil were the reason for proposing the goals of this thesis: analysis of the state of the art of low vision products in the world, particularly those with video magnification; proposal of a product that aggregates video-magnification to a reading stand in an innovative product; analysis of representative cases of design for health in Brazil, including ophthalmic design. As method, interviews, bibliographic and internet search along with patient observation were performed in order to support the project of a reading stand with a sliding video-magnification camera for low vision people. The resulting project has as common platform the commercially available product: a reading stand with a sliding magnifier in which the magnifier is replaced by a near reading video-magnification camera. This reading stand allows the user to read on a steady basis as the hand moves the ring around the camera to the right or to the left on a rail, maintaining the reading line and focus constant. Indicative elements are shown that the innovative design of this equipment presents advantages which may contribute favorably for the reading of low vision people, comparing with the equipment currently in the market. Through the socially responsible design, this thesis is meant to contribute to social inclusion of low vision people in Brazil.

This thesis presents the results of a mathematical analysis of various live load combinations on highway bridge spans up to 304.8 meters (1,000 feet) total lengths. The analysis included continuous beams, but only the results for simple beams is presented. The analysis was performed using an independently developed Microsoft EXCEL spreadsheet computation, based on superposition and classical mechanics. In this thesis, several actual bridge live loadings and several hypothetical live loadings were analyzed and compared to the American Association of State Highway and Transportation Officials Load and Resistance Factor Design method. Also considered was the new bridge design method adopted by the Louisiana Department of Transportation in March 2015. The evolution of bridge design loads is discussed, and the concept of the Military Load Classification is introduced and adapted to the bridge design analysis. The results of the analysis are presented, compared and interpreted for use in future bridge design.

Magnification mammography is a special technique used in cases where breast complaints are noticed by a woman or when an abnormality is found in a screening mammogram. The carcinogenic risk in mammography is related to the dose deposited in the glandular tissue of the breast rather than the adipose, and Average Glandular Dose (AGD) is the quantity taken into consideration during a mammographic exam. Direct measurement of the AGD is not feasible during clinical practice and thus, the incident air Kinetic Energy Released per unit of MAss (KERMA) on the breast surface is used to estimate the glandular dose, with the help of proper conversion factors. Additional conversion factors adapted for magnification and tube voltage are calculated, using Monte Carlo simulation. The effect of magnification factor, tube voltage and various anode/filter material combinations on AGD, ESD and PDD is also studied. Results demonstrate that, for fixed glandularity, the estimation of AGD utilizing conversion factors depends on magnification factor, anode/filter combination and tube voltage applied. AGD was found to increase mainly with filter material’s kabsorption edge, filter’s Al thickness, anode material’s k-emission edge and tube voltage. Rh/Nb, W/Zr, W/Nb, W/Mo and Mo/Nb are combinations resulting in lower AGD and higher ESD, compared to the Mo/Mo one. / -

A partir da constatação do limitado investimento no design de produtos de auxílio à visão subnormal no Brasil e de sua crescente demanda, esta tese teve por objetivo analisar o estado da arte dos produtos existentes no mundo, particularmente dos que oferecem ampliação eletrônica da imagem, propor um projeto de equipamento inovador que agrega videomagnificação a uma prancha de leitura, e analisar alguns casos pioneiros de design para a saúde no Brasil, inclusive oftalmológico. Como método foram realizadas entrevistas, pesquisas bibliográficas, por internet e observação de pacientes para embasar a proposta de projeto de prancha de leitura acoplada a câmera de videomagnificação para deficientes visuais. A proposta resultante tem como base comum o produto prancha de leitura acoplada a lupa já disponível no mercado em que no lugar da lupa será colocada uma câmera de vídeomagnificação para leitura de perto. Nesta prancha de base o usuário poderá ler de modo estável comandando por sua mão o movimento do anel em volta da câmera que por sua vez excursionará horizontalmente num trilho para manter a linha e o foco de leitura constantes. Evidenciam-se os elementos indicadores de que o design inovador deste equipamento apresenta vantagens em relação aos equipamentos atualmente existentes e que poderão contribuir para facilitar a leitura dos portadores de baixa visão. Por meio do design com responsabilidade social, este trabalho pretende dar uma contribuição para a inclusão do deficiente visual no Brasil. / Low investment in design for low vision and growing demand for low vision products in Brazil were the reason for proposing the goals of this thesis: analysis of the state of the art of low vision products in the world, particularly those with video magnification; proposal of a product that aggregates video-magnification to a reading stand in an innovative product; analysis of representative cases of design for health in Brazil, including ophthalmic design. As method, interviews, bibliographic and internet search along with patient observation were performed in order to support the project of a reading stand with a sliding video-magnification camera for low vision people. The resulting project has as common platform the commercially available product: a reading stand with a sliding magnifier in which the magnifier is replaced by a near reading video-magnification camera. This reading stand allows the user to read on a steady basis as the hand moves the ring around the camera to the right or to the left on a rail, maintaining the reading line and focus constant. Indicative elements are shown that the innovative design of this equipment presents advantages which may contribute favorably for the reading of low vision people, comparing with the equipment currently in the market. Through the socially responsible design, this thesis is meant to contribute to social inclusion of low vision people in Brazil.

Over the last few years, the ever-increasing use of the new emerging wireless communication systems has imposed a considerable challenge in the development of novel microwave devices that can support the high bit rates and wide bandwidths demanded by the society. Moreover, other of the main goals of the current microwave components' designers is the fact that these devices can withstand the increasingly higher RF power requirements that must be considered at the output stages of transmitters. In this context, several physical phenomena should be analyzed in order to maximize the so-called power handling capability (PHC) in microwave components. In particular, this thesis focuses on the study of the corona discharge breakdown, since it is a physical effect that may limit the peak power thresholds (also known as peak power handling capability or PPHC) of microwave devices. In this regard, the main aim of this work is the proposal of several design strategies to achieve a considerable improvement of the PPHC in different filtering structures. In this sense, this dissertation is divided into two main parts. On the one hand, the study of the corona discharge breakdown will be first focused on microstrip bandpass filters, where the variation of the maximum electric field strength will be analyzed, and different solutions based on dielectric covers, rounded open-circuit terminations, an anticorona lacquer or a commercial adhesive will be thoroughly investigated and compared. The main objective will be the maximization of the peak power levels, while the degradation of the unloaded quality factor of the resonators will be minimized as far as possible. On the other hand, the second part of this thesis dissertation deals with a similar exhaustively analysis in groove gap waveguides (GGWs). Furthermore, different topologies of bandpass filters based on this technology will be studied, focusing also on the type of the electric field's polarization. In a similar way, several design criteria will be proposed for improving the PPHC of these components, thereby achieving a significant enhancement and reaching the same peak power thresholds of the counterpart rectangular waveguide devices. Finally, all the solutions described above will be experimentally validated in diverse measurement campaigns carried out at the European High Power RF Space Laboratory to corroborate the proper and good performances of all of them. / A lo largo de los últimos años, el uso cada vez mayor de los nuevos sistemas de comunicación inalámbricos emergentes ha impuesto un reto considerable en el desarrollo de novedosos dispositivos de microondas que puedan soportar las altas tasas de bits y amplios anchos de banda demandados por la sociedad. Además, otro de los principales objetivos de los actuales diseñadores de componentes de microondas es el hecho de que estos dispositivos puedan soportar los requisitos de potencia RF cada vez más elevados que se deben considerar en las etapas de salida de los transmisores. En este contexto, diversos fenómenos físicos deben ser estudiados para maximizar la denominada capacidad de manejo de potencia (PHC, por sus siglas en inglés) en componentes de microondas. En particular, esta tesis doctoral se centra en el estudio de la descarga de corona, ya que es un efecto físico que puede limitar los umbrales de potencia de pico (también conocido como capacidad de manejo de la potencia de pico o PPHC, por sus siglas en inglés) de dispositivos de microondas. Por ello, el principal objetivo de este trabajo es la propuesta de varias estrategias de diseño para conseguir una mejora considerable de la PPHC en diferentes estructuras filtrantes. En este sentido, esta tesis se divide en dos partes principales. Por un lado, el estudio del efecto corona se centrará en primer lugar en filtros paso banda en tecnología microstrip, donde se analizará la variación de la intensidad máxima del campo eléctrico, así como también se investigarán y compararán a fondo diferentes soluciones basadas en cubiertas dieléctricas, terminaciones en circuito abierto redondeadas, una laca anticorona o un adhesivo comercial. El objetivo principal será maximizar los niveles de potencia de pico, mientras se minimizará en la medida de lo posible la degradación del factor de calidad de los resonadores. Por otro lado, la segunda parte de esta tesis doctoral aborda un análisis exhaustivo parecido en guías de onda groove-gap (GGWs, por sus siglas en inglés). Además, se estudiarán distintas topologías de filtros paso banda basados en esta tecnología, centrándose también en el tipo de polarización del campo eléctrico. Del mismo modo, se propondrán varios criterios de diseño para mejorar la PPHC de estos componentes, consiguiendo así una mejora significativa y alcanzando los mismos umbrales de potencia de pico que los dispositivos equivalentes en guía de onda rectangular. Finalmente, todas las soluciones descritas serán validadas experimentalmente en diversas campañas de medidas realizadas en el Laboratorio Europeo de Alta Potencia en RF para corroborar el correcto y buen funcionamiento de todas ellas. / Al llarg dels últims anys, l'ús cada vegada major dels nous sistemes de comunicació sense fils emergents ha imposat un repte considerable en el desenvolupament de nous dispositius de microones que puguen suportar les altes taxes de bits i grans amplades de banda demandades per la societat. A més, un altre dels principals objectius dels actuals dissenyadors de components de microones és el fet que aquests dispositius puguen suportar els requisits de potència RF cada vegada més elevats que s'han de considerar en les etapes d'eixida dels transmissors. En aquest context, diversos fenòmens físics han de ser estudiats per a maximitzar la denominada capacitat de maneig de potència (PHC, per les seues sigles en anglès) en components de microones. En particular, aquesta tesi doctoral se centra en l'estudi de la descàrrega de corona, ja que és un efecte físic que pot limitar els llindars de potència de pic (també conegut com a capacitat de maneig de la potència de pic o PPHC, per les seues sigles en anglès) de dispositius de microones. Per això, el principal objectiu d'aquest treball és la proposta de diverses estratègies de disseny per a aconseguir una millora considerable de la PPHC en diferents estructures filtrants. En aquest sentit, aquesta tesi es divideix en dues parts principals. Per un costat, l'estudi de l'efecte corona se centrarà en primer lloc en filtres passabanda en tecnologia microstrip, on s'analitzarà la variació de la intensitat màxima del camp elèctric, així com també s'investigaran i compararan a fons diferents solucions basades en cobertes dielèctriques, terminacions en circuit obert arredonides, una laca anticorona o un adhesiu comercial. L'objectiu principal serà maximitzar els nivells de potència de pic, mentre es minimitzarà en la mesura que siga possible la degradació del factor de qualitat dels ressonadors. Per l'altre costat, la segona part d'aquesta tesi doctoral aborda una anàlisi exhaustiva similar en guies d'ona groove-gap (GGWs, per les seues sigles en anglès). A més, s'estudiaran diferents topologies de filtres passabanda basats en aquesta tecnologia, centrant-se també en el tipus de polarització del camp elèctric. De la mateixa manera, es proposaran diversos criteris de disseny per a millorar la PPHC d'aquests components, aconseguint així una millora significativa i els mateixos llindars de potència de pic que els dispositius equivalents en guia d'ona rectangular. Finalment, totes les solucions descrites seran validades experimentalment en diverses campanyes de mesures realitzades en el Laboratori Europeu d'Alta Potència en RF per a corroborar el correcte i bon funcionament de totes elles. / Work supported by the Spanish Ministry of Science and Innovation (MCIN) and the State Agency of Research (AEI) through the Sub-Project C43 of the Coordinated Project PID2019-103982RB [MCIN/AEI/10.13039/501100011033]. Aitor Morales-Hernández has received a fellowship grant from the University of Alicante [UAFPU2018-054].

Uncertainty analysis is crucial to any thorough analysis of an engineering system. Traditional uncertainty analysis can be a tedious task involving numerous steps that can be error prone if conducted by hand. If conducted with the aid of a computer, these tasks can be computationally expensive. In either case, the process is quite rigid. If a parameter of the system is modified or the system configuration is changed, the entire uncertainty analysis process must be conducted again giving more opportunities for calculation errors or computation time. Modular uncertainty analysis provides a method to overcome all these obstacles of traditional uncertainty analysis. The modular technique is well suited for computation by a computer which makes the process somewhat automatic after the initial setup and computation errors are reduced. The modular technique implements matrix operations to conduct the analysis. This in turns makes the process more efficient than traditional methods because computers are well suited for matrix operations. Since the modular technique implements matrix operations, the method is adaptable to system parameter or configuration modifications. The modular technique also lends itself to quickly calculating other uncertainty analysis parameters such as the uncertainty magnification factor, and the uncertainty percent contribution. This dissertation will focuson the modular technique, the extension of the technique in the form the uncertainty magnification factor and uncertainty percent contribution, and the application of the modular technique to different type of energy systems. The modular technique is applied to an internal combustion engine with a bottoming organic Rankine cycle system, a combined heat and power system, and a heating, ventilation, and air conditioning system. The results show that the modular technique is well suited to evaluate complex engineering systems. The modular technique is also shown to perform well when system parameters or configurations are modified.