Slabsim: Simulador de dispositivos ópticos integrados

En los diseños y desarrollos de ingeniería, antes de comenzar la construcción e implementación de los objetivos de un proyecto, es necesario realizar una serie de análisis previos y simulaciones que corroboren las expectativas de la hipótesis inicial, con el fin de obtener una referencia empírica que satisfaga las condiciones de trabajo o funcionamiento de los objetivos de dicho proyecto. A menudo, los resultados que satisfacen las características deseadas se obtienen mediante la iteración de métodos de ensayo y error. Generalmente, éstos métodos utilizan el mismo procedimiento de análisis con la variación de una serie de parámetros que permiten adaptar una tecnología a la finalidad deseada. Hoy en día se dispone de computadoras potentes, así como algoritmos de resolución matemática que permiten resolver de forma veloz y eficiente diferentes tipos de problemas de cálculo. Resulta interesante el desarrollo de aplicaciones que permiten la resolución de éstos problemas de forma rápida y precisa en el análisis y síntesis de soluciones de ingeniería, especialmente cuando se tratan expresiones similares con variaciones de constantes, dado que se pueden desarrollar instrucciones de resolución con la capacidad de inserción de parámetros que definan el problema. Además, mediante la implementación de un código de acuerdo a la base teórica de una tecnología, se puede lograr un código válido para el estudio de cualquier problema relacionado con dicha tecnología. El desarrollo del presente proyecto pretende implementar la primera fase del simulador de dispositivos ópticos Slabsim, en cual se puede representar la distribución de la energía de una onda electromagnética en frecuencias ópticas guiada a través de una una guía dieléctrica plana, también conocida como slab. Este simulador esta constituido por una interfaz gráfica generada con el entorno de desarrollo de interfaces gráficas de usuario Matlab GUIDE, propiedad de Mathworks©, de forma que su manejo resulte sencillo e intuitivo para la ejecución de simulaciones con un bajo conocimiento de la base teórica de este tipo de estructuras por parte del usuario. De este modo se logra que el ingeniero requiera menor intervalo de tiempo para encontrar una solución que satisfaga los requisitos de un proyecto relacionado con las guías dieléctricas planas, e incluso utilizarlo para una amplia diversidad de objetivos basados en esta tecnología. Uno de los principales objetivos de este proyecto es la resolución de la base teórica de las guías slab a partir de métodos numéricos computacionales, cuyos procedimientos son extrapolables a otros problemas matemáticos y ofrecen al autor una contundente base conceptual de los mismos. Por este motivo, las resoluciones de las ecuaciones diferenciales y características que constituyen los problemas de este tipo de estructuras se realizan por estos medios de cálculo en el núcleo de la aplicación, dado que en algunos casos, no existe la alternativa de uso de expresiones analíticas útiles. ABSTRACT. The first step in engineering design and development is an analysis and simulation process which will successfully corroborate the initial hypothesis that was made and find solutions for a particular. In this way, it is possible to obtain empirical evidence which suitably substantiate the purposes of the project. Commonly, the characteristics to reach a particular target are found through iterative trial and error methods. These kinds of methods are based on the same theoretical analysis but with a variation of some parameters, with the objective to adapt the results for a particular aim. At present, powerful computers and mathematical algorithms are available to solve different kinds of calculation problems in a fast and efficient way. Computing application development is useful as it gives a high level of accurate results for engineering analysis and synthesis in short periods of time. This is more notable in cases where the mathematical expressions on a theoretical base are similar but with small variations of constant values. This is due to the ease of adaptation of the computer programming code into a parameter request system that defines a particular solution on each execution. Additionally, it is possible to code an application suitable to simulate any issue related to the studied technology. The aim of the present project consists of the construction of the first stage of an optoelectronics simulator named Slabsim. Slabism is capable of representing the energetic distribution of a light wave guided in the volume of a slab waveguide. The mentioned simulator is made through the graphic user interface development environment Matlab GUIDE, property of Mathworks©. It is designed for an easy and intuitive management by the user to execute simulations with a low knowledge of the technology theoretical bases. With this software it is possible to achieve several aims related to the slab waveguides by the user in low interval of time. One of the main purposes of this project is the mathematical solving of theoretical bases of slab structures through computing numerical analysis. This is due to the capability of adapting its criterion to other mathematical issues and provides a strong knowledge of its process. Based on these advantages, numerical solving methods are used in the core of the simulator to obtain differential and characteristic equations results that become represented on it.

Modeling and optimization of frequencies on congested bus lines

In this paper some mathematical programming models are exposed in order to set the number of services on a specified system of bus lines, which are intended to assist high demand levels which may arise because of the disruption of Rapid Transit services or during the celebration of massive events. By means of this model two types of basic magnitudes can be determined, basically: a) the number of bus units assigned to each line and b) the number of services that should be assigned to those units. In these models, passenger flow assignment to lines can be considered of the system optimum type, in the sense that the assignment of units and of services is carried out minimizing a linear combination of operation costs and total travel time of users. The models consider delays experienced by buses as a consequence of the get in/out of the passengers, queueing at stations and the delays that passengers experience waiting at the stations. For the case of a congested strategy based user optimal passenger assignment model with strict capacities on the bus lines, the use of the method of successive averages is shown.

Definición e implementación de métricas objetivas para la evaluación funcional del miembro superior: aplicación a población con lesión medular cervical

En personas que padecen una Lesión Medular cervical, la función de los miembros superiores se ve afectada en mayor o menor medida, dependiendo fundamentalmente del nivel de la lesión y de la severidad de la misma. El déficit en la función del miembro superior hace que la autonomía e independencia de las personas se vea reducida en la ejecución de Actividades de la Vida Diaria. En el entorno clínico, la valoración de la función del miembro superior se realiza principalmente con escalas clínicas. Algunas de ellas valoran el nivel de dependencia o independencia en la ejecución de Actividades de la Vida Diaria, como, por ejemplo, el índice de Barthel y la escala FIM (Medida de la Independencia Funcional). Otras escalas, como Jebsen-Taylor Hand Function, miden la función del miembro superior valorando la destreza y la habilidad en la ejecución de determinadas tareas funcionales. Estas escalas son generales, es decir, se pueden aplicar a distintas poblaciones de sujetos y a la presencia de distintas patologías. Sin embargo, existen otras escalas desarrolladas específicamente para valorar una patología concreta, con el objetivo de hacer las evaluaciones funcionales más sensibles a cambios. Un ejemplo es la escala Spinal Cord Independence Measure (SCIM), desarrollada para valorar Lesión Medular. Las escalas clínicas son instrumentos de medida estandarizados, válidos para su uso en el entorno clínico porque se han validado en muestras grandes de pacientes. No obstante, suelen poseer una elevada componente de subjetividad que depende principalmente de la persona que puntúa el test. Otro aspecto a tener en cuenta, es que la sensibilidad de las escalas es alta, fundamentalmente, a cambios groseros en el estado de salud o en la función del miembro superior, de forma que cambios sutiles en el sujeto pueden no ser detectados. Además, en ocasiones, poseen saturaciones en el sistema de puntuación, de forma que mejorías que se puedan producir por encima de un determinado umbral no son detectadas. En definitiva, estas limitaciones hacen que las escalas clínicas no sean suficientes, por sí mismas, para evaluar estrategias motoras del miembro superior durante la ejecución de movimientos funcionales, siendo necesaria la búsqueda de instrumentos de medida que aporten objetividad, complementen las valoraciones y, al mismo tiempo, intenten solventar las limitaciones que poseen las escalas. Los estudios biomecánicos son ejemplos de métodos objetivos, en los que diversas tecnologías se pueden utilizar para recoger información de los sujetos. Una concreción de estos estudios son los estudios cinemáticos. Mediante tecnología optoelectrónica, inercial o electromagnética, estos estudios proporcionan información objetiva acerca del movimiento realizado por los sujetos, durante la ejecución de tareas concretas. Estos sistemas de medida proporcionan grandes cantidades de datos que carecen de una interpretación inmediata. Estos datos necesariamente deben ser tratados y reducidos a un conjunto de variables que, a priori, posean una interpretación más sencilla para ser utilizados en la práctica clínica. Estas han sido las principales motivaciones de esta investigación. El objetivo principal fue proponer un conjunto de índices cinemáticos que, de forma objetiva, valoren la función del miembro superior; y validar los índices propuestos en poblaciones con Lesión Medular, para su uso como instrumentos de valoración en el entorno clínico. Esta tesis se enmarca dentro de un proyecto de investigación: HYPER (Hybrid Neuroprosthetic and Neurorobotic Devices for Functional Compensation and Rehabilitation of Motor Disorders, referencia CSD2009-00067 CONSOLIDER INGENIO 2010). Dentro de este proyecto se lleva a cabo investigación en el desarrollo de modelos, para determinar los requisitos biomecánicos y los patrones de movimiento de los miembros superiores en sujetos sanos y personas con lesión medular. Además, se realiza investigación en la propuesta de nuevos instrumentos de evaluación funcional en el campo de la rehabilitación de los miembros superiores. ABSTRACT In people who have suffered a cervical Spinal Cord Injury, upper limbs function is affected to a greater or lesser extent, depending primarily on the level of the injury and the severity of it. The deficit in the upper limb function reduces the autonomy and independence of persons in the execution of Activities of Daily Living. In the clinical setting, assessment of upper limb function is mainly performed based on clinical scales. Some value the level of dependence or independence in performing activities of daily living, such as the Barthel Index and the FIM scale (Functional Independence Measure). Other scales, such as the Jebsen-Taylor Hand Function, measure upper limb function in terms of the skill and ability to perform specific functional tasks. These scales are general, so can be applied to different populations of subjects and the presence of different pathologies. However, there are other scales developed for a specific injury, in order to make the functional assessments more sensitive to changes. An example is the Spinal Cord Independence Measure (SCIM), developed for people with Spinal Cord Injury. The clinical scales are standardized instruments measure, valid for use in the clinical setting because they have been validated in large patient samples. However, they usually have a high level of subjectivity which mainly depends on the person who scores the test. Another aspect to take into account is the high sensitivity of the scales mainly to gross changes in the health status or upper limb function, so that subtle changes in the subject may not be detected. Moreover, sometimes, have saturations in the scoring system, so that improvements which may occur above a certain threshold are not detected. For these reasons, clinical scales are not enough, by themselves, to assess motor strategies used during movements. So, it’s necessary to find measure instruments that provide objectivity, supplement the assessments and, at the same time, solving the limitations that scales have. Biomechanical studies are examples of objective methods, in which several technologies can be used to collect information from the subjects. One kind of these studies is the kinematic movement analysis. By means of optoelectronics, inertial and electromagnetic technology, these studies provide objective information about the movement performed by the subjects during the execution of specific tasks. These systems provide large quantities of data without easy and intuitive interpretation. These data must necessarily be treated and reduced to a set of variables that, a priori, having a simpler interpretation for their use in the clinical practice. These were the main motivations of this research. The main objective was to propose a set of kinematic indices, or metrics that, objectively, assess the upper limb function and validate the proposed rates in populations with Spinal Cord Injury, for use as assessment tools in the clinical setting. This dissertation is framed within a research project: HYPER (Neurorobotic Devices for Functional Compensation and Rehabilitation of Motor Disorders, grant CSD2009- 00067 CONSOLIDER INGENIO 2010). Within this research project, research is conducted in relation to the biomechanical models development for determining the biomechanical requirements and movement patterns of the upper limb in healthy and people with Spinal Cord Injury. Moreover, research is conducted with respect to the proposed of new functional assessment instruments in the field of upper limb rehabilitation.

Filmes de óxido de zinco e nitreto de zinco depositados por magnetron sputtering com diferentes pressões de argônio, oxigênio e nitrogênio.

O óxido de zinco é um material semicondutor que apresenta alta transparência óptica no espectro visível, alta energia de ligação de éxcitons e piezoeletricidade. Por suas propriedades, ele é utilizado na área de sensores, eletrodos transparentes e dispositivos optoeletrônicos. No entanto, sua utilização ainda é limitada pela dificuldade de obtenção de condutividade tipo p, cujo principal dopante é o nitrogênio, devido à assimetria de dopagem ocasionada por defeitos intrínsecos do material, dopagem em valências diferentes das esperadas e formação de níveis de aceitadores profundos na banda proibida. A aplicação em dispositivos piezoelétricos também exige alta resistividade e ótimas propriedades cristalinas. Muitos processos de deposição estabelecidos hoje ainda utilizam altas temperaturas, o que impede sua deposição sobre superfícies ou substratos sensíveis a altas temperaturas. O objetivo deste trabalho é desenvolver técnicas de deposição de filmes de ZnO, principalmente em baixas temperaturas ( 100°C), pelo método de magnetron sputtering de rádio frequência, para avaliar a influência dos gases de processo nas características estruturais, estequiométricas, elétricas e ópticas dos filmes. Para isso, foram obtidos filmes utilizando pressão total de argônio, e pressões parciais de argônio e oxigênio e argônio e nitrogênio, utilizando alvo cerâmico de óxido de zinco ou alvo metálico de zinco. Para alvo de ZnO, filmes com condutividade tipo n foram obtidos em ambiente de argônio, em condições que geraram deficiências de oxigênio. Filmes altamente resistivos foram obtidos com a utilização de pressão parcial de oxigênio no gás de processo, em condições que resultaram em filmes estequiométricos, inclusive com condutividade tipo p. Condutividade tipo p mais alta foi observada, apenas por ponta quente, para uma amostra obtida em argônio logo após a utilização de nitrogênio na câmara de processo, que provavelmente sofreu influência da dopagem não intencional do cobre, que foi identificado como um contaminante do processo devido à estrutura da câmara. Para alvo de Zn, observou-se a formação de nitreto de zinco, que demonstrou alta capacidade de oxidação em ambiente atmosférico, e portanto, transforma-se naturalmente ao longo do tempo ou por processos de oxidação térmica em ZnO dopado com nitrogênio. Filmes de ZnO produzidos a partir de nitreto de zinco foram os únicos dos testados que apresentaram fotoluminescência característica do ZnO, mesmo para processos onde não houve aquecimento intencional.

A Competitive assessment of the U.S. fiber optics industry /

Item 231-B-1

Simultaneous measurement of strain and temperature using the first- and second-order diffraction wavelengths of Bragg gratings

A method of discriminating between temperature and strain effects in fibre sensing using a conventionally written, in-fibre Bragg grating is presented. The technique uses wavelength information from the first and second diffraction orders of the grating element to determine the wavelength dependent strain and temperature coefficients, from which independent temperature and strain measurements can be made. The authors present results that validate this matrix inversion technique and quantify the strain and temperature errors which can arise for a given uncertainty in the measurement of the reflected wavelength.

Single polarisation fibre ring laser by utilising intracavity 45° tilted fibre Bragg grating

Single polarisation operation of fibre ring laser has been realised by employing an intracavity 45deg-tilted fibre Bragg grating (45deg-TFBG). The degree of polarisation up to 99.94% of the laser was demonstrated with good stability.

DNA hybridisation biosensor based on dual-peak long-period grating

Using an optical biosensor based on dual-peak long-period fibre grating, we demonstrate the detection of interactions between DNA biomolecules in real-time, showing a high sensitivity and reusability function.

Repetition rate multiplication by phase-only filtering with multi-cavity optical structures

We propose several all-pass spectrally-periodic optical structures composed of simple optical cavities for the implementation of repetition rate multipliers of periodic pulse train with uniform output train envelope by phase-only filtering, and analyze them in terms of robustness and accuracy.

Trans-oceanic 80Gbit/s single channel transmission using short period dispersion management

The authors demonstrate dispersion managed soliton transmission using short-period dispersion management, which is characterised by having a dispersion management period that is much shorter than the amplification period. Simulation results indicate that by optimisation of the system parameters single channel transmission at 80Gbit/s is possible over trans-oceanic distances. © IEE, 2000.

A compact, portable and low cost generic interrogation strain sensor system using an embedded VCSEL, detector and fibre Bragg grating

We present a compact, portable and low cost generic interrogation strain sensor system using a fibre Bragg grating configured in transmission mode with a vertical-cavity surface-emitting laser (VCSEL) light source and a GaAs photodetector embedded in a polymer skin. The photocurrent value is read and stored by a microcontroller. In addition, the photocurrent data is sent via Bluetooth to a computer or tablet device that can present the live data in a real time graph. With a matched grating and VCSEL, the system is able to automatically scan and lock the VCSEL to the most sensitive edge of the grating. Commercially available VCSEL and photodetector chips are thinned down to 20 µm and integrated in an ultra-thin flexible optical foil using several thin film deposition steps. A dedicated micro mirror plug is fabricated to couple the driving optoelectronics to the fibre sensors. The resulting optoelectronic package can be embedded in a thin, planar sensing sheet and the host material for this sheet is a flexible and stretchable polymer. The result is a fully embedded fibre sensing system - a photonic skin. Further investigations are currently being carried out to determine the stability and robustness of the embedded optoelectronic components. © 2012 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).