91 research outputs found

    Prescription of Maintenance Interventions by the New Generation of Eurocodes for Climate-Change Resilient Structures

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    The new generation of structural Eurocodes will include climate change adaption measures in order to enhance the climate resilience of infrastructures across Europe. This paper discusses the impact that climate change might have on reinforced concrete structures subjected to corrosion, and the associated challenges of the standardisation of adaptation measures. A resilience-based framework is proposed for the adaptation of structural codes to climate change-induced actions. Such an approach aims to provide the required adaptive capacity to the new structures in order to be able to respond to the uncertain future minimising the investment under unlikely scenarios. In that way, the strategy can be summarised as a climate change-adapted design plus an in-design maintenance plan. Future actions, such as mapping the future climate-related drivers of corrosion, the determination of the design values of these drivers, and the prescription of maintenance activities, should be further investigated. Although this paper focuses on the new structures that will be designed with the new codes, some of the insights can be extrapolated to the existing structures

    Assédio laboral e justa causa de resolução

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    O assédio laboral trata-se de um fenómeno social que ultrapassou já, com distinção, o teste do tempo. Nos últimos anos assistimos a um crescendo da preocupação com a saúde do trabalhador e o tema do assédio, como não poderia deixar de ser, foi associado a esta temática. Ainda que nem todos os trabalhadores sintam que esta é a sua realidade, o nosso objeto de estudo é a relação laboral do trabalhador comum, aquele que está, verdadeiramente, limitado pelos poderes disciplinar e de direção do empregador. Para tanto, o presente trabalho analisará o regime jurídico do assédio laboral e, em particular, este problema enquanto justa causa de resolução do contrato de trabalho.Workplace harassment is a social phenomenon that has passed the test of time with distinction. In recent years, we have witnessed a growing concern about workers’ health and the issue of harassment has, naturally, been brought to this discussion. Although this may not be the case for all employees, our object of study is the employment relationship of the common employee, the one who is truly limited by the disciplinary and management powers of the employer. To this end, the present work will analyse the legal regime of workplace harassment and how it may be invoked as a just cause of termination of the employment contract

    Probabilistic Safety Analysis of High Speed and Conventional Lines Using Bayesian Networks

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    [EN] A Bayesian network approach is presented for probabilistic safety analysis (PSA) of railway lines. The idea consists of identifying and reproducing all the elements that the train encounters when circulating along a railway line, such as light and speed limit signals, tunnel or viaduct entries or exits, cuttings and embankments, acoustic sounds received in the cabin, curves, switches, etc. In addition, since the human error is very relevant for safety evaluation, the automatic train protection (ATP) systems and the driver behavior and its time evolution are modelled and taken into account to determine the probabilities of human errors. The nodes of the Bayesian network, their links and the associated probability tables are automatically constructed based on the line data that need to be carefully given. The conditional probability tables are reproduced by closed formulas, which facilitate the modelling and the sensitivity analysis. A sorted list of the most dangerous elements in the line is obtained, which permits making decisions about the line safety and programming maintenance operations in order to optimize them and reduce the maintenance costs substantially. The proposed methodology is illustrated by its application to several cases that include real lines such as the Palencia-Santander and the Dublin-Belfast lines.Grande Andrade, Z.; Castillo Ron, E.; Nogal, M.; O'connor, A. (2016). Probabilistic Safety Analysis of High Speed and Conventional Lines Using Bayesian Networks. En XII Congreso de ingeniería del transporte. 7, 8 y 9 de Junio, Valencia (España). Editorial Universitat Politècnica de València. 362-371. https://doi.org/10.4995/CIT2016.2015.3428OCS36237

    Literatura infantil: proposta para o 1.º ciclo do ensino básico

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    A Literatura Infantil é hoje uma presença cada vez mais constante na sala de aula do 1.º Ciclo do Ensino Básico, das escolas portuguesas. Sendo que algumas das obras estudadas poderão ser mais adequadas do que outras, ao seleccionar as nossas tivemos em conta os quadros presentes em Cerrilho, Larronaga e Yubero, cujos parâmetros apontam para além da idade das crianças, sugestões sobre os temas, estrutura literária e o desenho das obras. Seguidamente apresentamos um conjunto de actividades onde o mediador/professor é alguém atento que conhece os passos da didáctica da Literatura Infantil. Duas das obras foram leccionadas na nossa turma, onde recolhemos dados que nos permitiram uma avaliação sobre a eficácia da nossa prática.Children's Literature is nowadays an increasingly constant presence in Portuguese primary school‟s classrooms. Since some of the works studied may be better suited than others, our selection of those have considered Cerrilho, Larronaga and Yubero‟s frameworks, whose parameters go far beyond the age of children, pointing out suggestions for themes, literary structure and design of the works. Then we present a set of activities where the mediator/teacher is someone attentive that knows the steps of teaching Children's Literature. Two of the works were studied in our class, where we collect data that allowed us to evaluate the effectiveness of our practice

    The role of multi-fidelity modelling in adaptation and recovery of engineering systems

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    Significant research has been conducted in identifying optimal recovery and adaptation decisions in disruptive scenarios using engineering models. In this context, an aspect that has been target of limited research is that of response times. Modelling is expected to grow progressively more complex as it becomes more accurate. Such complexity increases modelling efforts, and the promise of optimal adaptation and recovery may become hindered. The present work discusses the role of modelling fidelities in adaptation and recovery of systems, and in particular that of using a lower fidelity model that enables zero-time analyses of a system. A framework is proposed for using different fidelities in adaptation and recovery, considering system’s decision time requirements. The relevance of this analysis is researched in two traffic networks and results show that multi-fidelity models should be expected to play a key role in increasing the efficiency of optimal adaptation and recovery decisions

    Flood risk assessment for road infrastructures using Bayesian networks: case study of Santarem - Portugal

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    Assessing flood risks on road infrastructures is critical for the definition of mitigation strategies and adaptation processes. Some efforts have been made to conduct a regional flood risk assessment to support the decision-making process of exposed areas. However, these approaches focus on the physical damage of civil infrastructures without considering indirect impacts resulting from social aspects or traffic delays due to the functionality loss of transportation infrastructures. Moreover, existing methodologies do not include a proper assessment of the uncertainties involved in the risk quantification. This work aims to provide a consistent quantitative flood risk estimation and influence factor modelling for road infrastructures. To this end, a Flood Risk Factor (FRF) is computed as a function of hazard, vulnerability, and infrastructure importance factors. A Bayesian Network (BN) is constructed for considering the interdependencies among the selected input factors, as well as accounting for the uncertainties involved in the modelling process. The proposed approach allows weighting the relevant factors differently to compute the FRF and improves the understanding of the causal relations between them. The suggested method is applied to a case study located in the region of Santarem Portugal, allowing the identification of the sub-basins where the road network has the highest risks and illustrating the potential of Bayesian inference techniques for updating the model when new information becomes available

    Fatigue reliability using a multiple surface approach

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    Reliability analysis for offshore wind turbines fatigue is an effort demanding task. New trends in the design of these systems, such as, the usage of alternative computational fluid dynamics or finite element methods, are expected to further increase the effort needed to design these systems to fatigue. As a result, design techniques that enable practicable fatigue analysis are on demand. The present paper researches on how to use fatigue damage surfaces in order to assess stress-cycle fatigue reliability. A Gaussian process model is applied as a surrogate of fatigue damage. It allows to enclose multiple normally distributed interpolated surfaces. Probabilistic SN curves are considered, creating a double surface model, where the Gaussian process model is built on top of the curve. Analysis is performed on a 5MW turbine with a monopile foundation, and stress-cycle fatigue is assessed for the tower component. Results of the implementation show that there is a significant advantage in using surrogates of fatigue damage as only a limited number of time domain simulations is required for design. Fatigue design was assessed using a subset of 25 load cases. Moreover, the predictor surrogates accurately the design procedure within different material probabilistic characteristics, and accounting for loading uncertainty. Fatigue reliability assessment with these models may be performed with approximately 10% to 40% of the binned environmental conditions computational effort, which is of interest in the wind engineering sector. Nevertheless, the approach implemented may be applied to any component on any system, with the only requirement of defining a representative fatigue indicator

    Deciding how to decide under uncertainty: A methodology map to address decision- making under uncertainty

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    The 32nd European Safety and Reliability Conference (ESREL 2022), Dublin, Ireland, 28 August - 1 September 2022This paper presents a methodology map built on a thorough comparison of approaches that can be used to address decision-making under uncertainty based on the level of uncertainty considered. The methodology map is provided to help researchers and practitioners on the selection of the most convenient approach for their specific context. An overview of different approaches for decision-making under uncertainty is provided. Approaches are then compared to each other, where requirements, limits, pros, cons and different circumstances under which each approach is more appropriate are discussed. Four different approaches are studied, the cost-benefit analysis (CBA), Probabilistic decision tree (PDT), Robust decision-making (RDM), and Dynamic adaptation policy pathway (DAPP). Results show that different considerations are expected to rule the selection process. It should depend on the problem in-hand (e.g. type of uncertainty, the number of alternatives) and enclose a rationale that addresses its limitations (e.g. available time, fund). The developed work is expected to support researchers and practitioners in the selection of convenient approaches to inform decision-making based on available knowledge, with awareness of the implications of the selected approach over the final output that will support holistic decisions.University College Dubli

    The African Swine Fever Virus IAP Homolog Is a Late Structural Polypeptide

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    AbstractThe analysis of the complete nucleotide sequence of the African swine fever virus genome has revealed the existence of a number of genes potentially capable of modifying the host's response to the virus infection. In this report, we describe the results of the characterization of the A224L gene that encodes a novel member of the family of apoptosis inhibitors known as IAP proteins. A224L is expressed during the late phase of the infectious cycle, and its polypeptide product is assembled into virus particles

    Bridge management through digital twin-based anomaly detection systems: A systematic review

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    Bridge infrastructure has great economic, social, and cultural value. Nevertheless, many of the infrastructural assets are in poor conservation condition as has been recently evidenced by the collapse of several bridges worldwide. The objective of this systematic review is to collect and synthesize state-of-the-art knowledge and information about how bridge information modeling, finite element modeling, and bridge health monitoring are combined and used in the creation of digital twins (DT) of bridges, and how these models could generate damage scenarios to be used by anomaly detection algorithms for damage detection on bridges, especially in bridges with cultural heritage value. A total of 76 relevant studies from 2017 up to 2022 have been taken into account in this review. The synthesis results show a consensus toward the future adoption of DT for bridge design, management, and operation among the scientific community and bridge practitioners. The main gaps identified are related to the lack of software interoperability, the required improvement of the performance of anomaly-detection algorithms, and the approach definition to be adopted for the integration of DT at the macro scale. Other potential developments are related to the implementation of Industry 5.0 concepts and ideas within DT frameworks
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