Novel Parallelization Techniques for Computer Graphics Applications

Increasingly complex and data-intensive algorithms in computer graphics applications require software engineers to find ways of improving performance and scalability to satisfy the requirements of customers and users. Parallelizing and tailoring each algorithm of each specific application is a time-consuming task and its implementation is domain-specific because it can not be reused outside the specific problem in which the algorithm is defined. Identifying reusable parallelization patterns that can be extrapolated and applied to other different algorithms is an essential task needed in order to provide consistent parallelization improvements and reduce the development time of evolving a sequential algorithm into a parallel one. This thesis focuses on defining general and efficient parallelization techniques and approaches that can be followed in order to parallelize complex 3D graphic algorithms. These parallelization patterns can be easily applied in order to convert most kinds of sequential complex and data-intensive algorithms to parallel ones obtaining consistent optimization results. The main idea in the thesis is to use multi-threading techniques to improve the parallelization and core utilization of 3D algorithms. Most of the 3D algorithms apply similar repetitive independent operations on a vast amount of 3D data. These application characteristics bring the opportunity of applying multi-thread parallelization techniques on such applications. The efficiency of the proposed idea is tested on two common computer graphics algorithms: hidden-line removal and collision detection. Both algorithms are data-intensive algorithms, whose conversions from a sequential to a multithread implementation introduce challenges, due to their complexities and the fact that elements in their data have different sizes and complexities, producing work-load imbalances and asymmetries between processing elements. The results show that the proposed principles and patterns can be easily applied to both algorithms, transforming their sequential to multithread implementations, obtaining consistent optimization results proportional to the number of processing elements. From the work done in this thesis, it is concluded that the suggested parallelization warrants further study and development in order to extend its usage to heterogeneous platforms such as a Graphical Processing Unit (GPU). OpenCL is the most feasible framework to explore in the future due to its interoperability among different platforms

Comportamiento electroquímico del ion Ag (I) sobre electrodo de Pt en Cloruro de 1-Butil-3 Metil-Imidazolio (BMIMCl) entre 343-363 K

En este trabajo se investiga la reducción electroquímica sobre electrodo de Pt del ion Ag (I) disuelto en el líquido iónico Cloruro de 1-Butil-3-Metil-Imidazolio (BMIMCl), a temperaturas comprendidas entre 343 y 363 K, utilizando las técnicas de voltamperometría de onda cuadrada (SWV), voltamperometría cíclica (CV), voltamperometría convolutiva de potencial (CPSV), cronoamperometría (CA) y cronopotenciometría (CP). La reducción de Ag (I) a Ag (0) tiene lugar mediante un proceso reversible o cuasi-reversible (dependiendo de las condiciones de trabajo), produciéndose el intercambio electrónico entre una especie soluble y otra insoluble, sin que existan reacciones químicas acopladas a la etapa de transferencia de carga, ni fenómenos de adsorción. Se ha determinado el coeficiente de difusión (D) mediante CV, CPSV, CP y CA. La nucleación y el crecimiento cristalino juegan un papel importante en la electrodeposición de Ag metálica sobre Pt.Grado en Químic

Constraining our Universe with X-ray & Optical Cluster Data

We have used recent X-ray and optical data in order to impose some constraints on the cosmology and cluster scaling relations. Generically two kind of hypotheses define our model. First we consider that the cluster population is well described by the standard Press-Schechter (PS) formalism, and second, these clusters are supposed to follow scaling relations with mass: Temperature-Mass (T-M) and X-ray Luminosity-Mass (L_x - M). As a difference with many other authors we do not assume specific scaling relations to model cluster properties such as the usual $T-M$ virial relation or one observational determination of the $L_x-T$ relation. Instead we consider general free parameter scaling relations. With the previous model (PS plus scalings) we fit our free parameters to several X-ray and optical data with the advantage over many other works that we consider all the data sets at the same time. This prevents us from being inconsistent with some of the available observations. Among other interesting conclusions, we find that only low-density universes are compatible with all the data considered and that the degeneracy between $\Omega_m$ and $\sigma_8$ is broken. Also we obtain interesting limits on the parameters characterizing the scaling relations.Comment: 11 pages, 7 figures. MNRAS accepted versio

Predicted Planck Extragalactic Point Source Catalogue

An estimation of the number and amplitude (in flux) of the extragalactic point sources that will be observed by the Planck Mission is presented in this paper. The study is based on the Mexican Hat wavelet formalism introduced by Cayon et al. 2000. Simulations at Planck observing frequencies are analysed, taking into account all the possible cosmological, Galactic and Extragalactic emissions together with noise. With the technique used in this work the Planck Mission will produce a catalogue of extragalactic point sources above fluxes: 1.03 Jy (857 GHz), 0.53 Jy (545 GHz), 0.28 Jy (353 GHz), 0.24 Jy (217 GHz), 0.32 Jy (143 GHz), 0.41 Jy (100 GHz HFI), 0.34 Jy (100 GHz LFI), 0.57 Jy (70 GHz), 0.54 Jy (44 GHz) and 0.54 Jy (30 GHz), which are only slightly model dependent (see text). Amplitudes of these sources are estimated with errors below 15%. Moreover, we also provide a complete catalogue (for the point sources simulation analysed) with errors in the estimation of the amplitude below 10%. In addition we discuss the possibility of identifying different point source populations in the Planck catalogue by estimating their spectral indices.Comment: 13 pages, 2 figures, submitted to MNRA

Development of nanoestructured titanosilicate catalyst layers in monoliths

Los catalizadores heterogéneos soportados son una parte esencial de la industria química, y nuevos soportes o catalizadores se investigan constantemente. Los titanosilicatos, materiales zeotípicos microporosos, son investigados con frecuencia como soportes catalíticos. Los microreactores estructurados, con una alta relación superficie-volumen y transferencias de masa y calor mejoradas, sobrepasan algunas de las limitaciones de los reactores de lecho fijo. Teniendo en cuenta estas consideraciones, propusimos desarrollar un método reproducible para sintetizar capas de titanosilicato como soporte en los canales de monolitos cerámicos, para su uso en catálisis. Se sintetizaron cristales de alta pureza de dos titanosilicatos (ETS-10 y JDF-L1). Estos cristales se usaron para sembrar monolitos cerámicos usando varios métodos, de los cuales “dip coating” y sonicación ofrecieron los resultados más homogéneos. Sólo ETS-10 pudo depositarse con éxito; los cristales de JDF-L1 eran muy grandes para ello. Tras la siembra, se probaron distintos métodos de síntesis hidrotermal para el crecimiento de las capas. El método TiCl3-A fue el más reproducible y proporcionó las capas más uniformes. La fase cristalina obtenida en el crecimiento no fue ETS-10, como las semillas, sino JDF-L1, confirmada por XRD. Se prepararon polvos catalíticos de ambos titanosilicatos por intercambio iónico o impregnación, para su prueba en dos reacciones catalíticas: Epoxidación de Etileno y Oxidación Selectiva de CO (SELOX). Para la epoxidación de etileno, se prepararon catalizadores basados en plata. El tamaño de las partículas obtenidas en estos catalizadores fue muy pequeño para darse actividad catalítica, y las pruebas en planta mostraron resultados muy pobres. Para SELOX, se prepararon catalizadores basados en platino o nanopartículas CoPt3, que ofrecieron buena actividad catalítica, llegando a la conversión total de CO, dando CoPt3 mejores resultados como fase activa que Pt. Soportar el catalizador de Pt en los canales de un monolito provocó una mejora del rendimiento catalítico sobre el catalizador en polvo

Cortisol, Maternal Stress, and Breastfeeding Rate at Hospital Discharge: A Systematic Review

Introduction: Breastfeeding is considered the best way to provide essential and necessary nutrients to the newborn, intervening in its growth and development. However, early abandonment of this method is quite common, due to various factors such as stress. Objectives: To determine whether the level of postpartum cortisol can serve as an indicator of maternal stress and whether there is a relationship between the level of cortisol and the rate of exclusive breastfeeding (EBF) at hospital discharge. Methodology: Systematic review of the literature under the PRISMA guidelines. PubMed, Web of Science, CINAHL, and Scopus databases were used. Original articles published from 2017 to 2022 in English, French, Portuguese, and Spanish were included. All study designs were eligible. Of the 3,712 records initially identified, 15 studies were included in this review. Results: Elevated cortisol levels, due to immediate postpartum stressors, have direct effects on the performance of the essential hormones in breast milk production. The EBF rates are negatively influenced by perceived maternal stress. Conclusion: Cortisol levels may be a good indicator of the level of stress to which the mother is subjected during the immediate postpartum period