147 research outputs found

    Efficient Model Checking: The Power of Randomness

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    Exploring annotations for deductive verification

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    Visual anemometry: physics-informed inference of wind for renewable energy, urban sustainability, and environmental science

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    Accurate measurements of atmospheric flows at meter-scale resolution are essential for a broad range of sustainability applications, including optimal design of wind and solar farms, safe and efficient urban air mobility, monitoring of environmental phenomena such as wildfires and air pollution dispersal, and data assimilation into weather and climate models. Measurement of the relevant microscale wind flows is inherently challenged by the optical transparency of the wind. This review explores new ways in which physics can be leveraged to "see" environmental flows non-intrusively, that is, without the need to place measurement instruments directly in the flows of interest. Specifically, while the wind itself is transparent, its effect can be visually observed in the motion of objects embedded in the environment and subjected to wind -- swaying trees and flapping flags are commonly encountered examples. We describe emerging efforts to accomplish visual anemometry, the task of quantitatively inferring local wind conditions based on the physics of observed flow-structure interactions. Approaches based on first-principles physics as well as data-driven, machine learning methods will be described, and remaining obstacles to fully generalizable visual anemometry will be discussed.Comment: In revie

    Abstract Dependency Graphs for Model Verification

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    Trajectory planning based on adaptive model predictive control: Study of the performance of an autonomous vehicle in critical highway scenarios

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    Increasing automation in automotive industry is an important contribution to overcome many of the major societal challenges. However, testing and validating a highly autonomous vehicle is one of the biggest obstacles to the deployment of such vehicles, since they rely on data-driven and real-time sensors, actuators, complex algorithms, machine learning systems, and powerful processors to execute software, and they must be proven to be reliable and safe. For this reason, the verification, validation and testing (VVT) of autonomous vehicles is gaining interest and attention among the scientific community and there has been a number of significant efforts in this field. VVT helps developers and testers to determine any hidden faults, increasing systems confidence in safety, security, functional analysis, and in the ability to integrate autonomous prototypes into existing road networks. Other stakeholders like higher-management, public authorities and the public are also crucial to complete the VTT process. As autonomous vehicles require hundreds of millions of kilometers of testing driven on public roads before vehicle certification, simulations are playing a key role as they allow the simulation tools to virtually test millions of real-life scenarios, increasing safety and reducing costs, time and the need for physical road tests. In this study, a literature review is conducted to classify approaches for the VVT and an existing simulation tool is used to implement an autonomous driving system. The system will be characterized from the point of view of its performance in some critical highway scenarios.O aumento da automação na indústria automotiva é uma importante contribuição para superar muitos dos principais desafios da sociedade. No entanto, testar e validar um veículo altamente autónomo é um dos maiores obstáculos para a implantação de tais veículos, uma vez que eles contam com sensores, atuadores, algoritmos complexos, sistemas de aprendizagem de máquina e processadores potentes para executar softwares em tempo real, e devem ser comprovadamente confiáveis e seguros. Por esta razão, a verificação, validação e teste (VVT) de veículos autónomos está a ganhar interesse e atenção entre a comunidade científica e tem havido uma série de esforços significativos neste campo. A VVT ajuda os desenvolvedores e testadores a determinar quaisquer falhas ocultas, aumentando a confiança dos sistemas na segurança, proteção, análise funcional e na capacidade de integrar protótipos autónomos em redes rodoviárias existentes. Outras partes interessadas, como a alta administração, autoridades públicas e o público também são cruciais para concluir o processo de VTT. Como os veículos autónomos exigem centenas de milhões de quilómetros de testes conduzidos em vias públicas antes da certificação do veículo, as simulações estão a desempenhar cada vez mais um papel fundamental, pois permitem que as ferramentas de simulação testem virtualmente milhões de cenários da vida real, aumentando a segurança e reduzindo custos, tempo e necessidade de testes físicos em estrada. Neste estudo, é realizada uma revisão da literatura para classificar abordagens para a VVT e uma ferramenta de simulação existente é usada para implementar um sistema de direção autónoma. O sistema é caracterizado do ponto de vista do seu desempenho em alguns cenários críticos de autoestrad

    Accelerated Verification of Concurrent Systems

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    Accelerated Verification of Concurrent Systems

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    Defining the mechanistic toxicity of metal oxide nanoparticles in vitro, under physiologically relevant oxygen concentrations

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    Metal oxide nanoparticles (MONPs) are intended for use in numerous consumer applications, leading to inevitable human exposure. Previous work conducted in hyperoxic cell culture conditions (21% O2, 5% CO2) with nanoparticles (NPs) has proven the ability of some material types to induce genotoxicity and inflammatoxicity. Alteration in intracellular calcium [i(Ca2+)] signalling is involved in facilitating toxicity through the alteration of signal-transduction pathways, but there is less understanding of the impact of NPs exposure upon changes in such signalling pathways. Furthermore, whilst human cells cultured in ambient air may induce a particular toxicity profile, this may not be the same under the physiologic oxygen conditions experienced in the human body. Therefore, the aim of this study was to assess the impact of anatase TiO2 (NM-102), Rutile TiO2 (NM-104) and dextran coated superparamagnetic Fe3O4 (dSPIONs) upon monocytes (THP-1), macrophages (dTHP-1) and hepatocarcinoma (HepG2) cells in both an in vivo-resembling physioxia environment (5%O2, 5%CO2) and hyperoxic cell culture conditions (21%O2, 5%CO2). Their impact on i(Ca2+) homeostasis and how it relates to their potential genotoxic potential was also evaluated.Due to the importance of different physicochemical characteristics for the facilitation of toxicity, all MONPs were characterized. MONPs hydrodynamic diameter (HD) and ζ-potential (ζ) in PBS were identified using dynamic light scattering: NM-102: HD=391.9nm, ζ =7.1±2.0mV; NM-104: HD=255nm, ζ=14.6 +/- 2.1mV; dSPIONs: HD=88.6nm, ζ =10.4±1.3mV. The possible toxic effect of NPs depends on their concentration and duration of their interaction with cells. Therefore, following 24h exposure to dSPIONs (0-100µg/ml), concentration-dependent and cell-type-dependent (dTHP1>THP-1>HepG2) significant increases in NP-cellular interaction were observed, which was significantly greater in the physioxic culture environment. Concurrent, significant loss of dSPION-associated cell proliferation (evaluated using relative population doubling) in all cell lines and significant increases in DNA damage was also identified in HepG2 cells (using the cytokinesis block micronucleus assay), albeit only in physioxia. Exposure to ≥10ug/ml NM-102 and NM-104 resulted in significant, two-fold increases in micronuclei formation in HepG2 in both environments. All MONPs induced a significant increase in tumour necrosis factor-α and interleukin-8 secretion in all cell lines and oxygen culture environments. Increase in the production of the chemokines was correlated with the observed HepG2 cell genotoxicity. In all cell lines and cell culture environments, treatment for up to 5h with NM-102 or dSPIONs triggered cell type specific increases in i(Ca2+) that correlated with the reduction of cellular antioxidant glutathione (measured after 5h treatment with all the MONPs). After pre-treatment of the cell lines with antioxidant trollox in all cell culture environments i(Ca2+) appeared to be increased independently from the change of cellular redox status. Environment-specific biological interaction and impacts with regard to NP uptake, genotoxic effects, and consequence on cellular signaling mechanisms were only observed with dSPIONs in a physioxic culture environment, while NM-102 and NM-104 induced similar effects in both environments. The results presented in this study allow the conclusion that the environmental oxygen content has an impact on the NP toxicity profiles although it is NP dependent

    Handbook of Marine Model Organisms in Experimental Biology

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    "The importance of molecular approaches for comparative biology and the rapid development of new molecular tools is unprecedented. The extraordinary molecular progress belies the need for understanding the development and basic biology of whole organisms. Vigorous international efforts to train the next-generation of experimental biologists must combine both levels – next generation molecular approaches and traditional organismal biology. This book provides cutting-edge chapters regarding the growing list of marine model organisms. Access to and practical advice on these model organisms have become aconditio sine qua non for a modern education of advanced undergraduate students, graduate students and postdocs working on marine model systems. Model organisms are not only tools they are also bridges between fields – from behavior, development and physiology to functional genomics. Key Features Offers deep insights into cutting-edge model system science Provides in-depth overviews of all prominent marine model organisms Illustrates challenging experimental approaches to model system research Serves as a reference book also for next-generation functional genomics applications Fills an urgent need for students Related Titles Jarret, R. L. & K. McCluskey, eds. The Biological Resources of Model Organisms (ISBN 978-1-1382-9461-5) Kim, S.-K. Healthcare Using Marine Organisms (ISBN 978-1-1382-9538-4) Mudher, A. & T. Newman, eds. Drosophila: A Toolbox for the Study of Neurodegenerative Disease (ISBN 978-0-4154-1185-1) Green, S. L. The Laboratory Xenopus sp. (ISBN 978-1-4200-9109-0)
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