9 resultados para Elder Tobar

em Universidad Politécnica de Madrid


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Cuantificación de la actividad física en mujeres mayores.

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We show a procedure for constructing a probabilistic atlas based on affine moment descriptors. It uses a normalization procedure over the labeled atlas. The proposed linear registration is defined by closed-form expressions involving only geometric moments. This procedure applies both to atlas construction as atlas-based segmentation. We model the likelihood term for each voxel and each label using parametric or nonparametric distributions and the prior term is determined by applying the vote-rule. The probabilistic atlas is built with the variability of our linear registration. We have two segmentation strategy: a) it applies the proposed affine registration to bring the target image into the coordinate frame of the atlas or b) the probabilistic atlas is non-rigidly aligning with the target image, where the probabilistic atlas is previously aligned to the target image with our affine registration. Finally, we adopt a graph cut - Bayesian framework for implementing the atlas-based segmentation.

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We propose a level set based variational approach that incorporates shape priors into edge-based and region-based models. The evolution of the active contour depends on local and global information. It has been implemented using an efficient narrow band technique. For each boundary pixel we calculate its dynamic according to its gray level, the neighborhood and geometric properties established by training shapes. We also propose a criterion for shape aligning based on affine transformation using an image normalization procedure. Finally, we illustrate the benefits of the our approach on the liver segmentation from CT images.

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Around ten years ago investigation of technical and material construction in Ancient Roma has advanced in favour to obtain positive results. This process has been directed to obtaining some dates based in chemical composition, also action and reaction of materials against meteorological assaults or post depositional displacements. Plenty of these dates should be interpreted as a result of deterioration and damage in concrete material made in one landscape with some kind of meteorological characteristics. Concrete mixture like calcium and gypsum mortars should be analysed in laboratory test programs, and not only with descriptions based in reference books of Strabo, Pliny the Elder or Vitruvius. Roman manufacture was determined by weather condition, landscape, natural resources and of course, economic situation of the owner. In any case we must research the work in every facts of construction. On the one hand, thanks to chemical techniques like X-ray diffraction and Optical microscopy, we could know the granular disposition of mixture. On the other hand if we develop physical and mechanical techniques like compressive strength, capillary absorption on contact or water behaviour, we could know the reactions in binder and aggregates against weather effects. However we must be capable of interpret these results. Last year many analyses developed in archaeological sites in Spain has contributed to obtain different point of view, so has provide new dates to manage one method to continue the investigation of roman mortars. If we developed chemical and physical analysis in roman mortars at the same time, and we are capable to interpret the construction and the resources used, we achieve to understand the process of construction, the date and also the way of restoration in future.

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Este proyecto consiste en el dimensionamiento del proceso de licuación de una planta offshore para la producción de gas natural licuado, usando únicamente N2 como refrigerante, evitando de este modo riesgos potenciales que podrían surgir con el uso de refrigerantes mixtos compuestos de hidrocarburos. El proceso ha sido diseñado para acomodar 35,23 kg/s (aproximadamente un millón de toneladas por año) de gas natural seco, sin separación de gases licuados de petróleo (GLP) y ajustarlo dentro de los parámetros requeridos en las especificaciones del proceso. Para proceder al dimensionamiento del proceso de licuación de gas natural de la planta se ha empleado el programa Aspen Plus. Los sistemas floating production, storage and offloading para licuar el gas natural (LNG-FPSO), es una nueva unidad conceptual y un modo realista y efectivo para la explotación, recuperación, almacenamiento, transporte y agotamiento de los campos marginales de gas y las fuentes de gas asociadas offshore. En el proyecto se detalla el proceso, equipos necesarios y costes estimados, potencia aproximada requerida y un breve análisis económico. ABSTRACT This project consist of the dimensioning of a liquefaction process in an offshore plant to produce liquefied natural, using only N2 as refrigerant in the cooling cycles to avoid potential hazards of mixed hydrocarbon refrigerants. The process was designed to accommodate 35.23 kg/s (roughly 1 MTPA) of raw natural gas feed without separation of LPG, and fits within all parameters required in the process specifications. The plant has been designed with the computer tool Aspen Plus. The floating production, storage and offloading system for liquefied natural gas (LNGFPSO), is a new conceptual unit and an effective and realistic way for exploitation, recovery, storage, transportation and end-use applications of marginal gas fields and offshore associated-gas resources. The following report details the process, equipment needs and estimated costs, approximated power requirements, and a brief economic analysis.

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BioMet®Phon is a software application developed for the characterization of voice in voice quality evaluation. Initially it was conceived as plain research code to estimate the glottal source from voice and obtain the biomechanical parameters of the vocal folds from the spectral density of the estimate. This code grew to what is now the Glottex®Engine package (G®E). Further demands from users in laryngology and speech therapy fields instantiated the development of a specific Graphic User Interface (GUI’s) to encapsulate user interaction with the G®E. This gave place to BioMet®Phon, an application which extracts the glottal source from voice and offers a complete parameterization of this signal, including distortion, cepstral, spectral, biomechanical, time domain, contact and tremor parameters. The semantic capabilities of biomechanical parameters are discussed. Study cases from its application to the field of laryngology and speech therapy are given and discussed. Validation results in voice pathology detection are also presented. Applications to laryngology, speech therapy, and monitoring neurological deterioration in the elder are proposed.

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La segmentación de imágenes puede plantearse como un problema de minimización de una energía discreta. Nos enfrentamos así a una doble cuestión: definir una energía cuyo mínimo proporcione la segmentación buscada y, una vez definida la energía, encontrar un mínimo absoluto de la misma. La primera parte de esta tesis aborda el segundo problema, y la segunda parte, en un contexto más aplicado, el primero. Las técnicas de minimización basadas en cortes de grafos permiten obtener el mínimo de una energía discreta en tiempo polinomial mediante algoritmos de tipo min-cut/max-flow. Sin embargo, estas técnicas solo pueden aplicarse a energías que son representabas por grafos. Un importante reto es estudiar qué energías son representabas así como encontrar un grafo que las represente, lo que equivale a encontrar una función gadget con variables adicionales. En la primera parte de este trabajo se estudian propiedades de las funciones gadgets que permiten acotar superiormente el número de variables adicionales. Además se caracterizan las energías con cuatro variables que son representabas, definiendo gadgets con dos variables adicionales. En la segunda parte, más práctica, se aborda el problema de segmentación de imágenes médicas, base en muchas ocasiones para la diagnosis y el seguimiento de terapias. La segmentación multi-atlas es una potente técnica de segmentación automática de imágenes médicas, con tres aspectos importantes a destacar: el tipo de registro entre los atlas y la imagen objetivo, la selección de atlas y el método de fusión de etiquetas. Este último punto puede formularse como un problema de minimización de una energía. A este respecto introducimos dos nuevas energías representables. La primera, de orden dos, se utiliza en la segmentación en hígado y fondo de imágenes abdominales obtenidas mediante tomografía axial computarizada. La segunda, de orden superior, se utiliza en la segmentación en hipocampos y fondo de imágenes cerebrales obtenidas mediante resonancia magnética. ABSTRACT The image segmentation can be described as the problem of minimizing a discrete energy. We face two problems: first, to define an energy whose minimum provides the desired segmentation and, second, once the energy is defined we must find its global minimum. The first part of this thesis addresses the second problem, and the second part, in a more applied context, the first problem. Minimization techniques based on graph cuts find the minimum of a discrete energy in polynomial time via min-cut/max-flow algorithms. Nevertheless, these techniques can only be applied to graph-representable energies. An important challenge is to study which energies are graph-representable and to construct graphs which represent these energies. This is the same as finding a gadget function with additional variables. In the first part there are studied the properties of gadget functions which allow the number of additional variables to be bounded from above. Moreover, the graph-representable energies with four variables are characterised and gadgets with two additional variables are defined for these. The second part addresses the application of these ideas to medical image segmentation. This is often the first step in computer-assisted diagnosis and monitoring therapy. Multiatlas segmentation is a powerful automatic segmentation technique for medical images, with three important aspects that are highlighted here: the registration between the atlas and the target image, the atlas selection, and the label fusion method. We formulate the label fusion method as a minimization problem and we introduce two new graph-representable energies. The first is a second order energy and it is used for the segmentation of the liver in computed tomography (CT) images. The second energy is a higher order energy and it is used for the segmentation of the hippocampus in magnetic resonance images (MRI).

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The aim of this paper is to develop a probabilistic modeling framework for the segmentation of structures of interest from a collection of atlases. Given a subset of registered atlases into the target image for a particular Region of Interest (ROI), a statistical model of appearance and shape is computed for fusing the labels. Segmentations are obtained by minimizing an energy function associated with the proposed model, using a graph-cut technique. We test different label fusion methods on publicly available MR images of human brains.

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En esta tesis doctoral se estudian las variaciones de radón en el interior de dos viviendas similares de construcción nueva en Madrid, una de ellas ocupada y la otra no, que forman parte del mismo edificio residencial. La concentración de radón y los parámetros ambientales (presión, temperatura y humedad) se midieron durante ocho meses. La monitorización del gas radón se realizó mediante detectores de estado sólido. Simultáneamente, se adquirieron algunas variables atmosféricas de un modelo atmosférico. En el análisis de los datos, se utilizó principalmente el método de la Transformada Wavelet. Los resultados muestran que el nivel de radón es ligeramente más alto en la vivienda ocupada que en la otra. A partir del análisis desarrollado en este estudio, se encontró que había un patrón específico estacional en la concentración de radón interior. Además, se analizó también la influencia antropogénica. Se pudieron observar patrones periódicos muy similares en intervalos concretos sin importar si la vivienda está ocupada o no. Por otra parte, los datos se almacenaron en cubos OLAP. El análisis se realizó usando unos algoritmos de agrupamiento (clustering) y de asociación. El objetivo es descubrir las relaciones entre el radón y las condiciones externas como la presión, estabilidad, etc. Además, la metodología aplicada puede ser útil para estudios ambientales en donde se mida radón en espacios interiores. ABSTRACT The present thesis studies the indoor radon variations in two similar new dwellings, one of them occupied and the other unoccupied, from the same residential building in Madrid. Radon concentration and ambient parameters were measured during eight months. Solid state detectors were used for the radon monitoring. Simultaneously, several atmospheric variables were acquired from an atmospheric model. In the data analysis, the Wavelet Transform Method was mainly used. The results show that radon level is slightly higher in the unoccupied dwelling than in the other one. From the analysis developed in this study, it is found that a specific seasonal pattern exists in the indoor radon concentration. Besides, the anthropogenic influence is also analysed. Nearly periodical patterns could be observed in specific periods whether dwelling is occupied or not. Otherwise, data were stored in cubes OLAP. Analysis was carried out using clustering and association algorithms. The aim is to find out the relationships among radon and external conditions like pressure, stability, etc. Besides, the methodology could be useful to assess environmental studies, where indoor radon is measured.