Reliability-based optimization of steel structures using genetic algorithms and nonlinear finite elements

Congreso celebrado en la Escuela de Arquitectura de la Universidad de Sevilla desde el 24 hasta el 26 de junio de 2015.Uncertainties are inherent in material properties, geometry parameters and loading in structural design problems. In a realistic design, it is necessary to consider these types of uncertainties to ensure safety and quality. Design constraints are formulated in probabilistic terms such as probability of failure or reliability index. The process of design optimization enhanced by the addition of reliability constraints is referred as Reliability-Based Design Optimization (RBDO). Most of RBDO methods use classical mathematical optimization algorithms and require the gradients of objective function and constraints. This task sometimes can be cumbersome and hard because reliability constraints are implicit functions of design variables. However, the increased power of computers has made possible to apply heuristic methods, especially Genetic Algorithms in RBDO problems. In this paper Genetic Algorithm is combined with OpenSees, a nonlinear Finite Element Reliability Analysis software, to salve RBDO problems. Two numerical examples show the performance of the implementation

Multi-objective reliability based design of complex engineering structures using response surface methods

Extensive research contributions have been carried out in the field of Reliability-Based Design Optimisation (RBDO). Traditional RBDO methods deal with a single objective optimisation problem subject to probabilistic constraints. However, realistic problems in engineering practice require a multi-criteria perspective where two or more conflicting objectives need to be optimised. These type of problems are solved with multi-objective optimization methods, known as Multi-Objective Reliability Based Design Optimization (MORBDO) methods. Usually, significant computational efforts are required to solve these types of problems due to the huge number of complex finite element model evaluations. This paper proposes a practical and efficient approach based for talking this challenge. A multiobjective evolutionary algorithms (MOEAs) is combined with response surface method to obtain efficiently, accurate and uniformly distributed Pareto front. The proposed approach has been implemented into the OpenCossan software. Two examples are presented to show the applicability of the approach: an analytical problem where one of the objectives is the system reliability and the classic 25 bars transmission tower

Reliability-based design optimization under mixed aleatory/epistemic uncertainties : theory and applications

Reliability-based design optimization (RBDO) is a well-known design strategy in engineering. However, RBDO usually requires uncertainties to be modeled by statistical distributions. This requires the availability of sufficient sample size so that these variables can be represented accurately by probabilistic distributions. In the design of new systems and structures, usually there is a lack of information about some uncertain variables or parameters and only a reduced set of samples might be available. This prevents their treatment as probability distributions. This type of uncertainty is called epistemic uncertainty. This paper proposes two effective multiobjective evolutionary algorithms to solve design problems under both types of uncertainty: aleatory and epistemic. Two objective functions, namely the cost of the structures and the probability of failure, are considered. The results are Pareto fronts with a trade-off between cost and reliability associated with a specified level of confidence. Pareto fronts show minimum achievable values for the probability of failure for a given cost. The effect of the epistemic uncertainty on the solution is also investigated. An analytical example and two structural examples are solved to show the applicability of the approach and how epistemic uncertainty may affect the results

Elementos críticos en el entorno preoperatorio pediátrico: ¿Claves en la Seguridad?

La anestesiología moderna es una ciencia basada en la seguridad del paciente, adquiriendo ésta cada vez mayor relevancia. La velocidad de la comunicación, el advenimiento de las redes sociales y la torrencial cantidad de información en internet han promovido un paciente cada vez más enterado de su problema médico y una sociedad poco dispuesta a tolerar errores. Uno de los aspectos fundamentales de esta evolución se ve reflejada en la creciente importancia otorgada a la seguridad del paciente, y la responsabilidad del anestesiólogo como principal garante de este derecho. En este sentido, se han establecido múltiples guías y documentos que estratifican los riesgos evitables, tanto de manera generalizada como en subespecialidades de la anestesia y que ayudan al anestesiólogo a realizar su trabajo con las máximas garantías de seguridad. El artículo analizado define claramente los elementos críticos a tener en cuenta para minimizar los riesgos específicos en el entorno perioperatorio pediátrico basados en la última evidencia disponible de alta calidad

Acceleration of the DNA methylation clock among lynch syndrome‑associated mutation carriers

The research leading to these results has received funding from "la Caixa" Foundation (Ref: CAIXA2017/1) for library preparation, sequencing, and employment of research personnel, from The Fundacion Progreso y Salud, Junta de Andalucia, Spain and from DPI2017-84439-R of MINECO, Madrid and FEDER for sequencing and employment of research personnel. Finally, grant ref. A-BIO-470-UGR20 from University of Granada and FEDER has funded article processing charges (APC) and sample processing expenses.Background: DNA methylation (DNAm) age metrics have been widely accepted as an epigenetic biomarker for biological aging and disease. The purpose of this study is to assess whether or not individuals carrying Lynch Syndromeassociated mutations are affected in their rate of biological aging, as measured by the epigenetic clock. Methods: Genome-wide bisulfite DNA sequencing data were generated using DNA from CD4 + T-cells obtained from peripheral blood using 27 patient samples from Lynch syndrome families. Horvath’s DNAm age model based on penalized linear regression was applied to estimate DNAm age from patient samples with distinct clinical and genetic characteristics to investigate cancer mutation-related aging effects. Results: Both Lynch mutation carriers and controls exhibited high variability in their estimated DNAm age, but regression analysis showed steeper slope for the Lynch mutation carriers. Remarkably, six Lynch Syndrome-associated mutation carriers showed a strong correlation to the control group, and two sisters carrying Lynch Syndrome-associated mutations, with no significant difference in lifestyle and similar chronological age, were assigned very different DNAm age. Conclusions: Future studies will be required to explore, in larger patient populations, whether specific epigenetic age acceleration is predictive of time-to-cancer development, treatment response, and survival. Epigenetic clock DNAm metrics may be affected by the presence of cancer mutations in the germline, and thus show promise of potential clinical utility for stratified surveillance strategies based on the relative risk for imminent emergence of tumor lesions in otherwise healthy Lynch Syndrome-associated mutation carriers.La Caixa Foundation CAIXA2017/1Junta de AndaluciaSpanish Government DPI2017-84439-REuropean CommissionUniversity of Granada A-BIO-470-UGR2

Influence of socioeconomic status on community-acquired pneumonia outcomes in elderly patients requiring hospitalization: a multicenter observational study

The associations between socioeconomic status and community-acquired pneumonia outcomes in adults have been studied although studies did not always document a relationship. The aim of this multicenter observational study was to determine the association between socioeconomic status and community-acquired pneumonia outcomes in the elderly, in the context of a public health system providing universal free care to the whole population

Riesgo sísmico de la ciudad de Logroño

This paper contains part of the results obtained in the research project: “Resilient Logroño”. This work try to answer to the question: Is the city of Logroño prepared to face natural disasters? An especial treatment has posed in earthquakes because they are the most destructive disasters that can occur. This study deals with two aspects: seismic hazard and seismic vulnerability. In one hand, the earthquakes that have affected Logroño and its environment are described. In the other hand, existing buildings in the city are analysed to check if they are prepared to support a ground motion. Finally, the paper provides some previsions about building damages and human casualties that an earthquake with a macroseismic intensity of grade 6 could cause.Este artículo recoge parte de los resultados del proyecto de investigación “Logroño Resiliente”. Este trabajo trata de contestar a la pregunta: ¿Está la ciudad de Logroño preparada para hacer frente a desastres naturales? Se ha prestado una atención especial al riesgo sísmico ya que los terremotos son los fenómenos naturales más destructivos existentes. Este estudio se aborda en las dos vertientes que componen el riesgo sísmico: la peligrosidad sísmica y la vulnerabilidad de las edificaciones. Por un lado, se describen los sismos que han afectado a Logroño y su entorno. Por otro lado, se analiza la vulnerabilidad sísmica de los edificios existentes en Logroño. Finalmente, se dan algunas previsiones sobre daños en edificios y daños a la población que produciría un sismo con una intensidad macrosísmica de grado VI

Riesgo sísmico de la ciudad de Logroño

Este artículo recoge parte de los resultados del proyecto de investigación Logroño Resiliente. Este trabajo trata de contestar a la pregunta: ¿Está la ciudad de Logroño preparada para hacer frente a desastres naturales? Se ha prestado una atención especial al riesgo sísmico ya que los terremotos son los fenómenos naturales más destructivos existentes. Este estudio se aborda en las dos vertientes que componen el riesgo sísmico: la peligrosidad sísmica y la vulnerabilidad de las edificaciones. Por un lado, se describen los sismos que han afectado a Logroño y su entorno. Por otro lado, se analiza la vulnerabilidad sísmica de los edificios existentes en Logroño. Finalmente, se dan algunas previsiones sobre daños en edificios y daños a la población que produciría un sismo con una intensidad macrosísmica de grado VI.This paper contains part of the results obtained in the research project: Resilient Logroño. This work try to answer to the question: Is the city of Logroño prepared to face natural disasters? An especial treatment has posed in earthquakes because they are the most destructive disasters that can occur. This study deals with two aspects: seismic hazard and seismic vulnerability. In one hand, the earthquakes that have affected Logroño and its environment are described. In the other hand, existing buildings in the city are analysed to check if they are prepared to support a ground motion. Finally, the paper provides some previsions about building damages and human casualties that an earthquake with a macroseismic intensity of grade 6 could cause