Robust design optimization using Kriging models: Application to the robust design optimization of truss structures

El problema de diseño óptimo robusto de estructuras es una tarea computacionalmente costosa como consecuencia del acoplamiento de los procesos de cuantificación de incertidumbre y de optimización. Para hacer frente a este problema, en este artículo se propone una metodología, basada en modelos Kriging, para resolver de forma eficiente el problema de cuantificación de incertidumbre en el proceso de optimización. El modelo Kriging aproxima, de forma simultánea, la respuesta estructural en el dominio de diseño y en el dominio estocástico, permitiendo desacoplar los procesos de cuantificación de incertidumbre y de optimización. La metodología propuesta incluye un criterio de actualización de los modelos Kriging basado en la estimación del error en la predicción, que mejora la aproximación en las regiones cercanas al frente de Pareto. Se han resuelto 3 problemas para mostrar la aplicabilidad y la precisión de la metodología propuesta. Los resultados muestran que la metodología es adecuada para resolver el problema de diseño óptimo robusto con una precisión razonable y un número de evaluaciones del modelo de simulación muy inferior al que requieren los métodos convencionales.Conventional methods addressing the robust design optimization problem of structures usually require high computational requirements due to the nesting of uncertainty quantification within the optimization process. In order to address such a problem, this work proposes a methodology, based on Kriging models, to efficiently assess the uncertainty quantification in the optimization process. The Kriging model approximates the structural performance both in the design domain and in the stochastic domain, which allows to decouple the uncertainty quantification process and the optimization process. In addition, an infill criterion based on the variance of the Kriging prediction is included to update the Kriging model towards the global Pareto front. Three numerical examples show the applicability and the accuracy of the proposed methodology. The results show that the proposed method is appropriate to solve the robust design optimization problem with reasonable accuracy and a considerably lower number of function calls than required by conventional methods.Peer Reviewe

Biomarker combination is necessary for the assessment of Gaucher disease?

Biomarkers are useful tools to help in disease diagnosis and follow-up. According to the US Food & Drug Administration, biomarkers are defined as measurable elements that can be used as indicators in normal biological and pathological processes, or in response to an exposure or therapeutic interventions. Molecular, histologic, radiographic or physiological characteristics are some of those biomarkers (www.fda.gov). The term biomarker is currently being applied to molecular markers that define a specific biological status (1). Considering these factors, the “ideal” biomarker should fulfill susceptibility/risk, be reliable, and can be used for diagnosis, monitoring, prognosis, prediction and pharmacodynamic response. Some useful biomarkers such as the number of BCR/ABL transcripts in chronic myeloid leukemia serve as sensitive indicators that help in the monitoring of the molecular response, a quantitative instrument to monitor the long-term molecular response to therapy (2) or for example the serum concentration of M-component in monoclonal gammopathies ..

Allelic and phenotypic characterization of CYP2D6 and its encoded P450 cytochrome enzyme in a serie of Spanish type 1 Gaucher disease patients

Background: Cytochrome p450 is the main drug metabolic pathway. CYP2D6 is a highly polymorphic gene that encodes a cytochrome p450 enzyme with three activity levels: null, reduced and normal. Apart from another type of mutations CYP2D6 can suffer duplications and deletions of the entire gene. This is the pathway to metabolize one of the Gaucher disease treatments, whose dose administration is regulated according to the metabolizer phenotype, this being one of the administration limitations. Objectives: The aim of this paper is to evaluate the allelic frequencies and the metabolizer status of Gaucher type 1 patients in the Spanish population and compare it with the general Spanish population and other Gaucher disease groups. Methods: In this study, 109 type 1 Gaucher disease patients were analyzed with the xTAG®CYP2D6 kit to identify the CYP2D6 gene alleles. Results: We observed that eighty-seven patients could be classified as extensive, 14 as intermediate, 6 as poor and 2 as ultra-rapid metabolizers. The allelic duplication frequency is 5.5% and deletion is 4.5%. The most common allele is wild-type and the second is the null *4 allele. Intermediate phenotype frequency is higher than expected (p < 0.05). Conclusions: Our Spanish GD series shows an unexpected distribution of some alleles and phenotypic metabolizer status, in contrast to that previously reported in the Spanish population

On the Unification of Process Semantics: Logical Semantics

We continue with the task of obtaining a unifying view of process semantics by considering in this case the logical characterization of the semantics. We start by considering the classic linear time-branching time spectrum developed by R.J. van Glabbeek. He provided a logical characterization of most of the semantics in his spectrum but, without following a unique pattern. In this paper, we present a uniform logical characterization of all the semantics in the enlarged spectrum. The common structure of the formulas that constitute all the corresponding logics gives us a much clearer picture of the spectrum, clarifying the relations between the different semantics, and allows us to develop generic proofs of some general properties of the semantics.Comment: In Proceedings SOS 2011, arXiv:1108.279

El turismo micológico como fuente de ingresos y empleo en el medio rural. El caso de Castilla y León

Edible wild mushroom picking is becoming an important source of income in rural areas. The wide range of activitieswhich add value to mycological production (initial sale, transformation, marketing, etc.) include those related to tourismwhich can attract visitors to mushroom producing areas, leading to so-called mycological tourism. To date, no researchexists quantifying the importance thereof in rural areas endowed with such resources. The present research provides thefirst model to estimate this activity’s contribution to the economy of rural areas in the region of Castilla y León. The mainfinding to emerge evidences a close link between influx of visitors, who come principally to pick, and mycological productivityin the region. Based on this relation, we estimate four key variables to determine the impact which said activityhas on the regional economy as a whole: the number of overnight stays and trips made by mycological tourists, as wellas associated expenditure and employment created. Findings underscore the importance of this activity in the regionaltourism industry and point to its significance as a major market niche, particularly during the hotel low season. The needfor public administrators to implement a related management policy is also inferred. La recolección de hongos silvestres comestibles se está convirtiendo en un importante motor generador de rentasen el medio rural. Entre las variadas actividades que aportan valor a la cadena de producción, relacionadas con la micología (primera venta, transformación, comercialización, etc.), se encuentran aquellas de turismo capaces de atraer visitantes a los territorios productores o turismo micológico. En la actualidad no existe ninguna investigación que cuantifique su importancia en las áreas rurales con recurso. Así, en la presente investigación se desarrolla por primera vez un modelo, que se aplica para estimar esta aportación a la economía de los territorios rurales de la comunidad autónoma de Castilla y León. El principal hallazgo obtenido muestra que existe una fuerte relación entre afluencia de visitantes, cuya principal motivación es recolectar, y la productividad micológica del territorio. A partir de esta relación se estiman cuatro variables fundamentales para calcular la importancia de esta actividad en el total de esta economía: el número de pernoctaciones y de viajes realizados por turistas micológicos, así como el gasto asociado y el empleo generado. Los resultados expuestos muestran la importancia relativa de esta actividad sobre el sector del turismo rural en la región, lo que la convierte en un importante nicho de mercado de vital importancia, sobre todo en temporadas de baja ocupación de los establecimientos hoteleros, lo que hace necesario políticas de gestión de esta actividad por parte de las administraciones públicas.

Oral administration of cobalt acetate alters milk fatty acid composition, consistent with an inhibition of stearoyl-coenzyme A desaturase in lactating ewes

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A Study on the Dependence of Water Tree Permittivity with Time

During the growth of water trees in the insulation of a cable the distribution of the electric field is modified because of the local change of the dielectric properties of the material. It results a local enhancement of the electric field which could increase the risk of breakdown. The key factor is the permittivity of the water tree and the aim of the work is to determine its possible values and, particularly, the law of its increase with time during the of the trees. The paper presents permittivity measurements in uniform field in MV and powe

Macroscopic and microscopic description of phase transition in cerium isotopes

The spherical-to-deformed phase transition in cerium isotopes recently suggested to occur between Ce146 and Ce148 has been examined in the framework of the macroscopic algebraic collective model and two microscopic approaches, namely Skyrme-Hartree-Fock + Bardeen-Cooper-Schrieffer (BCS) calculations and the symmetry conserving configuration mixing method with Gogny energy density functionals applied also to the neighboring nuclei along the cerium isotopic chain. Possible spectral signatures of the phase transition are discussed in more details. The microscopic calculations predict octupole softness manifested by rather flat potential energy curves as a function of the octupole deformation parameter β3 for Ce146 and Ce148 and shape coexistence characterized by axially symmetric 0+ states, triaxial 2+ bands, and octupole deformation for the lowest 1- state

Bias correction of global irradiance modelled with the Weather Research and Forecasting model over Paraguay

In this contribution, we present a post-process analysis of Weather and Research Forecasting (WRF-ARW) model which combines a Kalman Filter with Model Output Statistics (MOS) for bias correction in order to improve the overall predicted values of GHI simulations over Paraguay.CONACYT - Consejo Nacional de Ciencias y TecnologíaPROCIENCI