The present work aims at enhancing the external quantum efficiencies of ultra-violet (UV) sensitive photodetectors (PDs) and light emitting diodes (LEDs)for any light polarization. Deep UV solid state devices are made out of AlGaN or MgZnO and their performances suffer from the high resistivity of their p-doped regions. They require transparent p-contacts; yet the most commonly used transparent contacts have low transmission in the UV: indium tin oxide (ITO) and nickel-gold (Ni/Au 5/5 nms) transmit less than 50% and 30% respectively at 300 nm. Here we investigate the use of surface plasmons (SPs) to design transparent p-contacts for AlGaN devices in the deep UV region of the spectrum. The appeal of using surface plasmon coupling arose from the local electromagnetic field enhancement near the metal surface as well as the increase in interaction time between the field and semiconductor if placed on top of a semiconductor. An in/out-coupling mechanism is achieved by using a grating consisting of two perpendicularly oriented sets of parallel aluminum lines with periods as low as 250 nm. The incident light is first coupled into SPs at the air/aluminum interface which then re-radiate at the aluminum/AlGaN interface and the photons energy is transferred to SP polaritons (SPPs) and back to photons. High transmission can be achieved not only at normal incidence but for a wider range of incident angles. iv A finite difference time domain (FDTD) package from R-Soft was used to simulate and design such aluminum gratings with transparency as high as 100% with tunable peak wavelength, bandwidth and angular acceptance. A rigorous coupled wave analysis (RCWA) was developed in Matlab to validate the FDTD results. The high UV transparency meshes were then fabricated using an e-beam assisted lithography lift-off process. Their electrical and optical properties were investigated. The electrical characterization was very encouraging; the sheet resistances of these meshes were lower than those of the conventionally used transparent contacts. The optical transmissions were lower than expected and the causes for the lower measurements have been investigated. The aluminum oxidation, the large metal grain size and the line edge roughness were identified as the main factors of inconsistency and solutions are proposed to improve these shortcomings. The effect of aluminum oxidation was calculated and the passivation of aluminum with SiO2 was evaluated as a solution. A cold deposition of aluminum reduced the aluminum grain size from 60 nm to 20 nm and the roughness from 5 nm to 0.5 nm. Furthermore, replacing the conventional lift-off process by a dry back-etch process led to much smoother metal line edges and much high optical transparency. The optical measurements were consistent with the simulations. Therefore, reduced roughness and smooth metal line edges were found to be especially critical considerations for deep UV application of the meshes.

No description available.

No description available.

A procedure for computational dosimetry to verify safety standards compliance of mobile communications base stations is presented. Compared with the traditional power density method, a procedure based on more rigorous physics was devised, requiring computation or measurement of the specific absorption rate (SAR) within the biological tissue of a person at an arbitrary distance. This uses a hybrid methd of moments/finite difference time domain (MoM/FDTD) numerical method in order to determine the field or SAR distribution in complex penetrable media, without the computational penalties that would result from a wholly FDTD simulation. It is shown that the transmitted power allowed by the more precise SAR method is, in many cases, between two and five times greater than that allowed by standards implementing the power flux density method.

Introduction: Ravelry is a website offering information and social media functions for people interested in knitting. All content is user-supplied, including thousands of searchable records of knitting patterns and yarns. The aim of this thesis is to describe the way these are organised and classified and how this relates to systems used in other contexts and to the expectations of site members regarding both presentation and search functions. Method: Based in domain analysis theory and the concept of serious leisure, the knitting community on Ravelry and its information databases were studied through content analysis of the website, a literature review of pattern and yarn presentation, and a user survey. Results and analysis: The presentation of products on the website contains the information expected within this domain. Users are generally satisfied with the information given but have come to expect more details here than from other sources. The search function enables specific searches, but is too complex for certain users and is sometimes seen as old-fashioned or hard to understand. Members express varying degrees of understanding of the website’s community base. Conclusion: Ravelry has set up a knowledge organisation system and presentation pages that meet its members’ expectations in terms of information content. The search function and layout is not as popular, but efficient for many respondents. This is a two years master’s thesis in Library and Information Science. / Inledning: Ravelry är en webbplats med information och sociala mediefunktioner för stickintresserade. Allt innehåll kommer från användarna, inklusive beskrivningar av tusentals sökbara stickmönster och garner. Syftet med studien är att beskriva hur dessa organiseras och klassificeras i förhållande till system som används i andra sammanhang och till medlemmarnas förväntningar. Metod: Utifrån domänanalysteori och begreppet ”serious leisure” undersöktes Ravelrys medlemmar och databaser genom innehållsanalys av webbplatsen, en litteraturstudie av mönster- och garnpresentation samt en användarenkät. Resultat och analys: Presentationen av produkter innehåller den information som förväntas inom domänen. Användarna är generellt sett nöjda med informationen som presenteras. Sökfunktionen möjliggör specificerade sökningar, men är för komplex för vissa användare och kan ses som gammaldags och svår att förstå. Medlemmarna uttrycker olika grader av förståelse för att allt material kommer från användarna. Slutsats: Ravelrys kunskapsorganisation och presentationssidor möter medlemmarnas förväntningar. Söksystemet och dess layout är inte lika populära, men effektivt för många respondenter.

[EN] Fiber grating sensors and devices have demonstrated outstanding capabilities in both telecommunications and sensing areas, due to their well-known advantageous characteristics. Therefore, one of the most important motivations lies in the potential of customized fiber gratings to be suitably employed for improving the interrogation process of optical fiber sensors and systems. This Ph.D. dissertation is focused on the study, design, fabrication and performance evaluation of customized fiber Bragg gratings (FBGs) and long period gratings (LPGs) with the double aim to present novel sensing technologies and to enhance the response of existing sensing systems. In this context, a technique based on time-frequency domain analysis has been studied and applied to interrogate different kind of FBGs-based sensors. The distribution of the central wavelength along the sensing structures has been demonstrated, based on a combination of frequency scanning of the interrogating optical pulse and optical time-domain reflectometry (OTDR), allowing the detection of spot events with good performance in terms of measurand resolution. Moreover, different customized FBGs have been interrogated using a technology inspired on the operation principle of microwave photonics (MWP) filters, enabling the detection of spot events using radio-frequency (RF) devices with modest bandwidth. The sensing capability of these technological platforms has been fruitfully employed for implementing a large scale quasi-distributed sensor, based on an array of cascaded FBGs. The potentiality of LPGs as fiber optic sensors has also been investigated in a new fashion, exploiting the potentials of MWP filtering techniques. Besides, a novel approach for simultaneous measurements based on a half-coated LPG has been proposed and demonstrated. Finally, the feasibility of FBGs as selective wavelength filters has been exploited in sensing applications; an alternative approach to improve the response and performance of Brillouin distributed fiber sensors has been studied and validated via experiments. The performance of the reported sensing platforms have been analyzed and evaluated so as to characterize their impact on the fiber sensing field and to ultimately identify the use of the most suitable technology depending on the processing task to be carried out and on the final goal to reach. / [ES] Los sensores y dispositivos en fibra basados en redes de difracción han mostrado excepcionales capacidades en el ámbito de las telecomunicaciones y del sensado, gracias a sus excelentes propiedades. Entre las motivaciones más estimulantes destaca la posibilidad de fabricar redes de difracción ad-hoc para implementar y/o mejorar las prestaciones de los sensores fotónicos. Esta tesis doctoral se ha enfocado en el estudio, diseño, fabricación y evaluación de las prestaciones de redes de difracción de Bragg (FBGs) y de redes de difracción de periodo largo (LPGs) personalizadas con el fin de desarrollar nuevas plataformas de detección y a la vez mejorar la respuesta y las prestaciones de los sensores fotónicos ya existentes. En este contexto, una técnica basada en el análisis tiempofrecuencia se ha estudiado e implementado para la interrogación de sensores en fibra basados en varios tipos y modelos de FBGs. Se ha analizado la distribución de la longitud de onda central a lo largo de la estructura de sensado, gracias a una metodología que conlleva el escaneo en frecuencia del pulso óptico incidente y la técnica conocida como reflectometria óptica en el dominio del tiempo (OTDR). De esta manera se ha llevado a cabo la detección de eventos puntuales, alcanzando muy buenas prestaciones en términos de resolución de la magnitud a medir. Además, se han interrogado varias FBGs a través de una técnica basada en el principio de operación de los filtros de fotónica de microondas (MWP), logrando así la detección de eventos puntuales usando dispositivos de radio-frecuencia (RF) caracterizados por un moderado ancho de banda. La capacidad de sensado de estas plataformas tecnológicas ha sido aprovechada para la realización de un sensor quasi-distribuido de gran alcance, formado por una estructura en cascada de muchas FBGs. Por otro lado, se han puesto a prueba las capacidades de las LPGs como sensores ópticos según un enfoque novedoso; para ello se han aprovechados las potencialidades de los filtros de MWP. Asimismo, se ha estudiado y demostrado un nuevo método para medidas simultáneas de dos parámetros, basado en una LPG parcialmente recubierta por una película polimérica. Finalmente, se ha explotado la viabilidad de las FBGs en cuanto al filtrado selectivo en longitud de onda para aplicaciones de sensado; para ello se ha propuesto un sistema alternativo para la mejora de la respuesta y de las prestaciones de sensores ópticos distribuidos basados en el scattering de Brillouin. En conclusión, se han analizado y evaluado las prestaciones de las plataformas de sensado propuestas para caracterizar su impacto en el ámbito de los sistemas de detección por fibra y además identificar el uso de la tecnología más adecuada dependiendo de la tarea a desarrollar y del objetivo a alcanzar. / [CA] Els sensors i dispositius en fibra basats en xarxes de difracció han mostrat excepcionals capacitats en l'àmbit de les telecomunicacions i del sensat, gràcies a les seus excel¿lents propietats. Entre les motivacions més estimulants destaca la possibilitat de fabricar xarxes de difracció ad-hoc per a implementar i/o millorar les prestacions de sensors fotònics. Esta tesi doctoral s'ha enfocat en l'estudi, disseny, fabricació i avaluació de les prestacions de xarxes de difracció de Bragg (FBGs) i de xarxes de difracció de període llarg (LPGs) personalitzades per tal de desenvolupar noves plataformes de detecció i al mateix temps millorar la resposta i les prestacions dels sensors fotònics ja existents. En este context, una tècnica basada en l'anàlisi temps-freqüència s'ha estudiat i implementat per a la interrogació de sensors en fibra basats en diversos tipus i models de FBGs. S'ha analitzat la distribució de la longitud d'ona central al llarg de l'estructura de sensat, gràcies a una metodologia que comporta l'escaneig en freqüència del pols òptic incident i la tècnica coneguda com reflectometria òptica en el domini del temps (OTDR). D'esta manera s'ha dut a terme la detecció d'esdeveniments puntuals, aconseguint molt bones prestacions en termes de resolució de la magnitud a mesurar. A més, s'han interrogat diverses FBGs a través d'una tècnica basada en el principi d'operació dels filtres de fotònica de microones (MWP), aconseguint així la detecció d'esdeveniments puntuals utilitzant dispositius de ràdio-freqüència (RF) caracteritzats per un moderat ample de banda. La capacitat de sensat d'aquestes plataformes tecnològiques ha sigut aprofitada per a la realització d'un sensor quasi-distribuït a llarga escala, format per una estructura en cascada de moltes FBGs. D'altra banda, s'han posat a prova les capacitats de les LPGs com a sensors òptics segons un enfocament nou; per a això s'han aprofitat les potencialitats dels filtres de MWP. Així mateix, s'ha estudiat i demostrat un nou mètode per a mesures simultànies de dos paràmetres, basat en una LPG parcialment recoberta per una pel¿lícula polimèrica. Finalment, s'ha explotat la viabilitat de les FBGs pel que fa al filtrat selectiu en longitud d'ona per a aplicacions de sensat; per això s'ha proposat un sistema alternatiu per a la millora de la resposta i de les prestacions de sensors òptics distribuïts basats en el scattering de Brillouin. S'han analitzat i avaluat les prestacions de les plataformes de sensat propostes per a caracteritzar el seu impacte en l'àmbit dels sistemes de detecció per fibra i a més identificar l'ús de la tecnologia més adequada depenent de la tasca a desenvolupar i de l'objectiu a assolir. / Ricchiuti, AL. (2016). Design and fabrication of customized fiber gratings to improve the interrogation of optical fiber sensors [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/66343 / TESIS / Premios Extraordinarios de tesis doctorales

Sweden has the ambition to be the world leading country leveraging the opportunities of digitalization in the healthcare sector. In parallel, the Swedish Research Council highlights that conducting more clinical studies is essential to improve the healthcare. Henceforth, considering the need for increased operational efficiency as an enabler for increased clinical activity, a digital transformation of the industry was identified as a potential catalyst. The study thus utilizes a cognitive work analysis framework to investigate the potential benefits and risks of digitizing the functional operations at a contract management department for clinical studies at a Swedish university hospital. The aim is thereafter to determine the appropriate properties necessary to consider managing a digital transformation. The analysis identified three key benefits from a digitization. 1) transparent data sharing, 2) standardized contract management and 3) efficient operations. These three aspects are currently insufficient at the department hindering the objective of increasing the clinical activity. The study found that a digital transformation would be suitable in order to mitigate these insufficiencies and consequently facilitating the achievement of the objectives. Thereafter, the study found the key properties to consider managing a digital transformation to be interoperability, quality, adaptability and usability. In addition, safety was found critical to be considered in the transformation as the contract management department acts under rigid laws and regulations on ethics and patient security with which digitized processes must comply. The results contribute to the field of cognitive systems engineering. However, the study has limitations regarding the reliability and generalizability of the results. The findings are based on a single case study, which may not be representative for the industry in general nor for university hospitals in particular. In addition, since no actual digitalization effort was performed at the organization during the study, appropriate properties key to consider in the digital transformation are speculative by design. Consequently, it is necessary to study an actual implementation process in future research and whether the proposed considerations are sufficient in order to realize the suggested benefits of such a digitalization. / Sverige har ett övergripande mål att vara det ledande landet när det gäller att dra nytta av digitaliseringens möjligheter inom sjukvården. Dessutom understryker Vetenskapsrådet att det är centralt för förbättrad sjukvård att öka antalet kliniska studier i landet. Följaktligen, med tanke på behovet av en ökad operativ effektivitet, identifierade författarna det av intresse att studera digitalisering av branschen. Studien tillämpar således ett kognitivt ramverk för arbetsanalys i syfte att undersöka de potentiella fördelarna eller riskerna med att digitalisera den funktionella verksamheten hos en kontrakthanteringsavdelning för kliniska studier vid ett stort svenskt universitetssjukhus. Målsättningen är därefter att ta fram lämpliga egenskaper som är nödvändiga att beakta vid hanteringen av den digitala transformationen. Kontrakthanteringsavdelningen fanns att inneha brister i sina arbetsprocesser gällande transparens, effektivitet och standardisering vilket hindrar målet avseende ökad klinisk aktivitet. Studien visade att en digital transformation skulle vara nödvändig för att motverka dessa brister, samt för att möjliggöra en uppskalning av organisationen. Ett annat specifikt förbättringsområde som skulle underlättas av en digital transformation visade sig vara förbättrad synkronisering mellan arbetsprocesser. Vidare fann studien att de mest kritiska egenskaperna nödvändiga att beakta, vid hantering av en digital transformation, skulle vara interoperabilitet, kvalitet, anpassningsförmåga och användbarhet. Dessutom är säkerhet en egenskap som visat sig vara kritisk att beakta vid digitalisering då kontrakthanteringsavdelningen lyder under stränga lagar och föreskrifter beträffande etik och patientsäkerhet. Resultaten bidrar till forskningsområdet cognitive systems engineering. Studien har dock vissa begränsningar gällande tillförlitlighet och generaliserbarhet. Resultaten är baserade på en enfallstudie, som eventuellt inte är representativ för branschen i allmänhet eller för universitetssjukhus i synnerhet. Dessutom, då ingen digitaliseringsinsats utfördes under studien är de viktiga egenskaperna att beakta i den digitala transformationen enbart spekulativa. Således är det i framtida forskning viktigt att studera en faktisk implementation och då studera om föreslagna beaktanden är tillräckliga för att utnyttja digitaliseringens möjligheter.

L'objet de cette thèse est d'étudier les systèmes de cointégration fractionnaire de forme triangulaire mais également d'analyser l'apport de ces systèmes dans la modélisation des co-mouvements au sein des marchés financiers internationaux. La thèse s'articule autour de six chapitres équitablement répartis entre contributions économétriques et économiques. Concernant l'approche économétrique, un intérêt particulier est donné à l'estimation de ces systèmes en absence d'information sur les paramètres d'intérêts. Dans cette optique, plusieurs techniques d'estimation sont analysées et développées, essentiellement dans le domaine des fréquences car celui-ci permet un traitement semi-paramétrique des paramètres de nuisances. Les performances de ses estimateurs sont étudiés à travers des simulations mais également à travers l'étude des propriétés asymptotiques. Concernant l'approche économique, une première contribution exploite la cointégration fractionnaire pour révéler l'existence d'un système de taux de change entre certains pays Asiatiques. Une deuxième contribution porte sur l'analyse des interdépendances entre le marché du pétrole et divers taux de change au niveau de la volatilité. Une troisième contribution introduit un processus d'apprentissage adaptatif dans un modèle monétaire à plusieurs pays afin d'étudier sous quelles conditions un système de taux de change peut émerger. / The aim of the thesis is to study a triangular form of fractional cointegration systems and to investigate whether these systems allow to model the comovements in international financial markets. The thesis is organized around six chapters. Three of them are theory-oriented and the three others are empirics-oriented. Concerning the econometric approach, a particular interest is devoted to the estimation of these systems when all parameters of interest are unknown. To this extent, several estimation techniques are investigated and introduced, essentially in frequency domain as it allows a semi-parametric treatment of the nuisance parameters. Most of times, the performance of these estimators are studied by means of simulations but the asymptotic theory is also developed. Concerning the economic approach, a first contribution applies the fractional cointegration theory to reveal the existence of an exchange rate system between several Asian countries. A second contribution deals with the risk interdependences between the crude oil market and several exchange rates. A third contribution considers an adaptive learning mechanism in a multi-country monetary model to investigate the conditions under which an exchange rate system is likely to emerge.

A dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in ful lment of the requirements for the degree of Master of Science in Engineering. Johannesburg, 2015 / The work presented extends and contributes to research in Non-Intrusive Load Monitoring (NILM), focussing on steady-state and transient power measurement disaggregation techniques for circuits containing household ap- pliances. Although previous work in this area has produced and evaluated a wide range of NILM approaches, much of it has involved the use of datasets captured from real-world household implementations. In such cases, the lack of accurate ground truth data makes it di cult to assess disaggregation tech- niques. In the research presented, three NILM techniques are comparatively evaluated using measurements from typical household appliances assembled within a laboratory environment, where accurate ground truth data could be compiled to complement the measurements. This allows for the accu- racy of the various disaggregation approaches to be precisely evaluated. It is demonstrated that the correlation of transient event edges in aggregated power measurements to individual appliance transient exemplars performs better than the matching of steady-state power levels against individual ap- pliance state combinations. Furthermore, the transient approach is shown to be the most appropriate technique for further development. / MT2017

No Brasil, em nível federal, a exploração mineral está submetida a ordenamentos normativos. A Agência Nacional de Mineração (ANM) é o ente regulador, atuando como protagonista na concessão, fiscalização e cumprimento de legislação específica para fiscalizar e fomentar a exploração dos recursos minerais e, portanto, deve organizar e tornar público os atos normativos que produz. A pesquisa apresenta diretrizes para organizar, disseminar e recuperar os atos normativos da ANM, enquanto documentos normativos, a partir dos pressupostos teóricos e metodológicos da Análise de Domínio, para a organização do conhecimento e recuperação da informação dentro de domínio específico - Mineração no Brasil. Apresenta reflexão sobre a conceituação e os aspectos formais da documentação jurídica, pela qual os atos normativos são manifestados. Das leituras específicas sobre documentação jurídica na Administração Pública Federal, foi organizado glossário com as principais espécies documentais, considerando o contexto da ANM. Apresenta análise descritiva do domínio Mineração a partir de: resumo histórico da atividade de regulação no Brasil; dos principais diplomas legais; dos pressupostos do Direito Minerário; e de sucinto perfil do órgão regulador. As leituras para descrever o domínio, principalmente dos atos normativos e diplomas legais utilizados nas atividades de regulação da mineração no Brasil, permitiram elencar vários conceitos pertinentes ao domínio estudado, os quais deram origem à terminologia da mineração no Brasil. Apresenta análise exploratória do menu legislação do portal das agências reguladoras do Brasil e do Sicon, Legin e LexML Da análise, foi verificado que, apesar de boa parte das agências possuírem catálogos on-line para os acervos de suas bibliotecas e também para seus atos normativos (legislação), muitas delas duplicam a forma de disponibilizar as informações normativas e não há padrão na organização e disseminação de tais documentos, principalmente com relação à representação temática, o que dificulta a recuperação da informação. Os resultados da análise exploratória evidenciaram que há um grande hiato entre o tratamento dos documentos normativos disponibilizados pelos órgãos do Poder Legislativo, quando comparado com os dos órgãos do Poder Executivo, estes necessitam estruturar e padronizar as atividades, tornando o tratamento, disseminação e recuperação mais eficiente e confiável. A partir das reflexões teóricas e dos resultados da análise exploratória, considerando o perfil da comunidade discursiva e a tipologia documental, foram definidos os metadados que contemplam as especificidades dos atos normativos da ANM e os campos de acesso para a ferramenta de busca avançada do futuro Sistema de Recuperação de Informação. Os metadados refletem contexto de produção, peculiaridades, disseminação, recuperação e uso, dos atos normativos pela comunidade discursiva (servidores da ANM; procuradores da AGU a serviço da ANM; e mineradores). A definição e implementação das diretrizes para o tratamento e a disseminação dos atos normativos da ANM é prerrogativa para que informação relevante e pertinente seja recuperada pelos usuários aptos a atribuírem valor estratégico e agregarem novos valores à informação na tomada de decisões; o que otimiza as atividades dos servidores da Autarquia e, consequentemente, a tramitação dos processos minerários. / In Brazil, exploring minerals requires specific mining laws and legal acts, which are made by the National Mining Agency (NMA). This governmental agency is responsible for regulating and boosting mineral resources exploration in the country. NMA deals with the concession, inspection and compliance of the Brazilian mineral resources exploration. Furthermore, to fulfill its mission, NMA must organize and publicize all legal acts about mining regulation. The goal of the research was to define procedures and guidelines to organize, disseminate and retrieve these legal acts based on theoretical and methodological statements Domain Analysis. Considering that acts are classified as legal documents, conceptions about them and legal information were introduced to highlight their features. Legal documents have specific form and demand different management in comparison to other administrative documents. In order to justify the use of Domain Analysis statements and also approaches recommended by Hjørland a descriptive analysis of Mining Domain in Brazil was presented. This description was based on the historical summary of the regulation activity in Brazil, main assumptions of mining law, main legal acts and a brief profile of the NMA. Afterwards, metadata were presented, analyzed and selected considering features of legal acts and the contexts of production, dissemination, retrieving and use in a state institution. This study also presented the results of exploratory analysis of the databases of Brazilian regulatory agencies and prominent legal databases - LexML and Federal Senate. Ensuring fast and effective access to relevant, reliable and consistent information that would enable the discursive community to improve its decision-taking process and to optimize its activities, speeding up the procedures of mining processes and improving Brazilian economy.