Topology optimization tools are useful for distributing material in a geometric domain to match targets for mass, displacement, structural stiffness, and other characteristics as closely as possible. Topology optimization tools are especially applicable to additive manufacturing applications, which provide nearly unlimited freedom for customizing the internal and external architecture of a part. Existing topology optimization tools, however, do not take full advantage of the capabilities of additive manufacturing. Prominent tools use micro- or meso-scale voids or artificial materials to parameterize the topology optimization problem, but they use filters, penalization functions, and other schemes to force convergence to regions of fully dense (solid) material and fully void (open) space in the final structure as a means of accommodating conventional manufacturing processes. Since additive manufacturing processes are capable of fabricating intermediate densities (e.g., via porous mesostructures), significant performance advantages could be achieved by preserving and exploiting those features during the topology optimization process. Towards this goal, a topology optimization tool has been created by combining homogenization with parametric smoothing functions. Rectangular mesoscale voids are used to represent material topology. Homogenization is used to analyze its properties. B-spline based parametric smoothing functions are used to control the size of the voids throughout the design domain, thereby smoothing the topology and reducing the number of required design variables relative to homogenization-based approaches. Resulting designs are fabricated with selective laser sintering technology, and their geometric and elastic properties are evaluated experimentally. / text

El análisis de supervivencia trata de la evaluación estadística de variables que miden el tiempo transcurrido hasta un evento de interés. Una particularidad que ha de considerar el análisis de supervivencia son datos censurados. Éstos aparecen cuando el tiempo de interés no puede ser observado exactamente y la información al respecto es parcial. Se distinguen diferentes tipos de censura: un tiempo censurado por la derecha está presente si el tiempo de supervivencia es sabido mayor a un tiempo observado; censura por izquierda está dada si la supervivencia es menor que un tiempo observado. En el caso de censura en un intervalo, el tiempo está en un intervalo de tiempo observado, y el caso de doble censura aparece cuando, también, el origen del tiempo de supervivencia está censurado.La primera parte del Capítulo 1 contiene un resumen de la metodología estadística para datos censurados en un intervalo, incluyendo tanto métodos paramétricos como no-paramétricos. En la Sección 1.2 abordamos el tema de censura noinformativa que se supone cumplida para todos los métodos presentados. Dada la importancia de métodos de optimización en los demás capítulos, la Sección 1.3 trata de la teoría de optimización. Esto incluye varios algoritmos de optimización y la presentación de herramientas de optimización. Se ha utilizado el lenguaje de programación matemática AMPL para resolver los problemas de maximización que han surgido. Una de las características más importantes de AMPL es la posibilidad de enviar problemas de optimización al servidor 'NEOS: Server for Optimization' en Internet para que sean solucionados por ese servidor.En el Capítulo 2, se presentan los conjuntos de datos que han sido analizados. El primer estudio es sobre la supervivencia de pacientes de tuberculosis co-infectados por el VIH en Barcelona, mientras el siguiente, también del área de VIH/SIDA, trata de usuarios de drogas intra-venosas de Badalona y alrededores que fueron admitidos a la unidad de desintoxicación del Hospital Trias i Pujol. Un área completamente diferente son los estudios sobre la vida útil de alimentos. Se presenta la aplicación de la metodología para datos censurados en un intervalo en esta área. El Capítulo 3 trata del marco teórico de un modelo de vida acelerada con una covariante censurada en un intervalo. Puntos importantes a tratar son el desarrollo de la función de verosimilitud y el procedimiento de estimación de parámetros con métodos del área de optimización. Su uso puede ser una herramienta importante en la estadística. Estos métodos se aplican también a otros modelos con una covariante censurada en un intervalo como se demuestra en el Capítulo 4.Otros métodos que se podrían aplicar son descritos en el Capítulo 5. Se trata sobre todo de métodos basados en técnicas de imputación para datos censurados en un intervalo. Consisten en dos pasos: primero, se imputa el valor desconocido de la covariante, después, se pueden estimar los parámetros con procedimientos estadísticos estándares disponibles en cualquier paquete de software estadístico.El método de maximización simultánea ha sido implementado por el autor con el código de AMPL y ha sido aplicado al conjunto de datos de Badalona. Presentamos los resultados de diferentes modelos y sus respectivas interpretaciones en el Capítulo 6. Se ha llevado a cabo un estudio de simulación cuyos resultados se dan en el Capítulo 7. Ha sido el objetivo comparar la maximización simultánea con dos procedimientos basados en la imputación para el modelo de vida acelerada. Finalmente, en el último capítulo se resumen los resultados y se abordan diferentes aspectos que aún permanecen sin ser resueltos o podrían ser aproximados de manera diferente. / Survival analysis deals with the evaluation of variables which measure the elapsed time until an event of interest. One particularity survival analysis has to account for are censored data, which arise whenever the time of interest cannot be measured exactly, but partial information is available. Four types of censoring are distinguished: right-censoring occurs when the unobserved survival time is bigger, left-censoring when it is less than an observed time, and in case of interval-censoring, the survival time is observed within a time interval. We speak of doubly-censored data if also the time origin is censored.In Chapter 1 of the thesis, we first give a survey on statistical methods for interval-censored data, including both parametric and nonparametric approaches. In the second part of Chapter 1, we address the important issue of noninformative censoring, which is assumed in all the methods presented. Given the importance of optimization procedures in the further chapters of the thesis, the final section of Chapter 1 is about optimization theory. This includes some optimization algorithms, as well as the presentation of optimization tools, which have played an important role in the elaboration of this work. We have used the mathematical programming language AMPL to solve the maximization problems arisen. One of its main features is that optimization problems written in the AMPL code can be sent to the internet facility 'NEOS: Server for Optimization' and be solved by its available solvers.In Chapter 2, we present the three data sets analyzed for the elaboration of this dissertation. Two correspond to studies on HIV/AIDS: one is on the survival of Tuberculosis patients co-infected with HIV in Barcelona, the other on injecting drug users from Badalona and surroundings, most of whom became infected with HIV as a result of their drug addiction. The complex censoring patterns in the variables of interest of the latter study have motivated the development of estimation procedures for regression models with interval-censored covariates. The third data set comes from a study on the shelf life of yogurt. We present a new approach to estimate the shelf lives of food products taking advantage of the existing methodology for interval-censored data.Chapter 3 deals with the theoretical background of an accelerated failure time model with an interval-censored covariate, putting emphasize on the development of the likelihood functions and the estimation procedure by means of optimization techniques and tools. Their use in statistics can be an attractive alternative to established methods such as the EM algorithm. In Chapter 4 we present further regression models such as linear and logistic regression with the same type of covariate, for the parameter estimation of which the same techniques are applied as in Chapter 3. Other possible estimation procedures are described in Chapter 5. These comprise mainly imputation methods, which consist of two steps: first, the observed intervals of the covariate are replaced by an imputed value, for example, the interval midpoint, then, standard procedures are applied to estimate the parameters.The application of the proposed estimation procedure for the accelerated failure time model with an interval-censored covariate to the data set on injecting drug users is addressed in Chapter 6. Different distributions and covariates are considered and the corresponding results are presented and discussed. To compare the estimation procedure with the imputation based methods of Chapter 5, a simulation study is carried out, whose design and results are the contents of Chapter 7. Finally, in the closing Chapter 8, the main results are summarized and several aspects which remain unsolved or might be approximated in another way are addressed.

Syftet med rapporten är att sammanställa branschbaserat underlag för värdering av hållbart byggande som belyser vikten för val av ytterväggskonstruktion till flerbostadshus. Byggbranschen har länge fokuserat på att minska byggnadsverks energi- och miljöpåverkan under förvaltningsskedet. Det har haft mycket goda resultat och i dagsläget står förvaltningsskedet för ca 50 procent av hållbara byggnaders totala energianvändning. Projektering med långsiktigt perspektiv är nyckeln till hållbart byggande eftersom små förändringar kan ha stor inverkan under längre tid. Detta medför ökad betydelse för effektivisering under byggskedet. Utvecklingen av hållbara byggnader har resulterat i framtagning av nollenergi- och passivhus. De byggkoncepten ställer högre krav på klimatskalets byggtekniska egenskaper. Klimatskalet innefattar tak, grund, fönster, dörrar och ytterväggar. Samtliga komponenter har stor inverkan på byggnadens egenskaper. Rapporten belyser endast betydelsefulla egenskaper och olika aspekter för hållbara ytterväggskonstruktioner och hur de skall värderas. Rapportens mål är att ta fram ett anpassningsbart bedömningsverktyg med värderingsunderlag från 9 olika aspekter. Aspekterna som bedöms är byggbarhet, brand, fukt, estetik, förvaltning, inomhusmiljö, energiförluster, livscykelkostnad och miljöpåverkan. Bedömningsverktyget visualiseras som en mall där poängsättning används för aspekterna vilket möjliggör tydliga jämförelser mellan konstruktioner. Fakta analyseras och hämtas från en litteraturstudie samt intervjuer med en byggnadskonstruktör, en brand- och en fuktkonsult. De ligger till grund för bedömningsverktygets utformning. För att kunna tillämpa bedömningsmallen i byggbranschen väljs 6 ytterväggskonstruktioner med olika uppbyggnad och egenskaper. De är anpassade för koncepthus med hållbart byggande och uppnår krav från Boverkets byggregler och Passivhuskonceptet. Ytterväggskonstruktionerna prövas i mallen och våra resultat visar att mallen kan tillämpas och åskådliggöra skillnader mellan konstruktionerna. Ytterväggarna erhåller ett generellt betyg samt ett viktat betyg som utgår från en anpassningsbar viktfaktor. Möjlighet för vidareutveckling finns för bedömningsmallen. Mallen är generell och tillämpningsbar på konstruktioner med andra egenskaper än de valda i rapporten. Rapporten indikerar på att mallen kan anpassas för att möjliggöra val av fördelaktiga konstruktioner för olika klimatzoner och beställarens ändamål. / The report aims to bring together industry-based data for evaluation of sustainable building that shows the importance of the choice regarding exterior wall construction for apartment buildings. The construction industry has focused on reducing the energy and environmental impact on buildings during the management phase for a long time. The results have been positive and to this date, the management phase stands for 50 percent of sustainable buildings total energy use. Designing with a long-term perspective is the key to sustainable building, because small changes can have a big impact over time. The importance of energy efficiency during the construction phase has increased. The results of the development regarding sustainable building have increased the production of zero energy- buildings and passive houses. The new concepts of building technology are placing higher demands on the technical properties of the building envelope. A building envelope includes roofs, foundation, windows, doors and exterior walls. All components have a major impact on the technical properties of a building, but the report only highlights significant aspects of sustainable exterior wall constructions and how they should be evaluated. The goal of the report is to develop an adapted assessment tool with evaluation data from 9 different aspects. The aspects that we will review in the report is constructability, fire, moisture, aesthetics, management, indoor environment, energy losses from the exterior wall construction, life cycle cost and environmental impact. The assessment tool is portrayed as a template that rates and scores different exterior wall construction. This enables clear comparisons between structures. The basic facts for the report are retrieved from a literature study. Interviews with a structural engineer and a fire- and moisture consultant have been conducted for a deeper view on how the construction industry evaluates and scores exterior wall construction. To apply the assessment template for trade and industry, 6 exterior wall constructions with different structures and properties were selected. They were suitable for conceptual houses with sustainable building technology and are the basis for achieving requirements from National board of housing and passivehouse rules. The different exterior wall constructions were tested on the template and the results show that the model can be applied positively on them. The different constructions receive a general grade and a weighted grade. The weighted grade is based on a customizable weight factor. The assessment template illustrated the differences between them. Possibilities for further development of the assessment template exist. It’s possible to apply the template on structures with different kind of properties than the ones chosen for this project. The template can be a tool for choosing a construction based on the demands from a client and it can be adapted to different kind of climate zones.