Littérature scientifique sur le sujet « Numerical platforms »
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Articles de revues sur le sujet "Numerical platforms"
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Junlai, Li, Xie Yonghe, Wu Weiguo et Zhang Chi. « Analysis of the Dynamic Response of Offshore Floating Wind Power Platforms in Waves ». Polish Maritime Research 27, no 4 (1 décembre 2020) : 17–25. http://dx.doi.org/10.2478/pomr-2020-0062.
Texte intégralRésumé :
Abstract Floating wind power platforms are in constant motion due to waves when deployed at sea. This motion directly affects the stability and safety of the platform. Therefore, it is very important to study the laws governing the platform’s dynamic response. In this paper, the dynamic characteristics of an offshore floating wind power platform were analysed under nine different sets of operating conditions using a numerical calculation method. Following this, a scaled 1:50 platform model was tested in a tank. Model tests were carried out with different wave conditions, and dynamic response data for the platform were measured and analysed. The hydrodynamic variation rules of floating wind power generation platform in waves were obtained. Some effective measures for maintain the stability and safety of wind power platforms are put forward that can provide a reference for dynamic stability research and the design of floating wind power platforms in the future.
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Tian, Kun, Xintian Zhuang et Beibei Yu. « The Incentive and Supervision Mechanism of Banks on Third-Party B2B Platforms in Online Supply Chain Finance Using Big Data ». Mobile Information Systems 2021 (18 mai 2021) : 1–16. http://dx.doi.org/10.1155/2021/9943719.
Texte intégralRésumé :
The incentive and supervision design of cooperation between banks and B2B platforms was studied under the electronic warehouse receipt pledge financing model. Under the assumptions of B2B platform risk, neutrality, and risk aversion, a principal-agent model for cooperation was established between banks and B2B platforms. Its purpose was to expand and compare the models by adding supervision variables. It also helps to analyze the effects of risk aversion coefficients on effort level, fixed payment, incentive coefficients, and the impact of bank income. This paper has analyzed the banking system’s incentives and supervision mechanisms by performing numerical analysis on big data. We have used MATLAB for numerical analysis. The results show that banks’ expected benefits when cooperating with risk-neutral B2B platforms are always greater than the expected benefits obtained when cooperating with risk-averse B2B platforms. But when banks act, the increase in profits exceeds the cost of regulatory measures. Besides, when the bank takes supervisory measures, the profit will be greater than the profit without supervisory measures. Hence, the B2B platform’s ability to recover losses is positively correlated with the bank’s expected utility. The cost coefficient of the B2B platform is negatively correlated with the bank’s expected utility. The risk aversion degree does not affect the optimal effort level of the B2B platform, but it affects the optimal fixed payment and the optimal incentive coefficient.
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Liu, Yincheng. « Numerical Simulation of Interaction between Kulluk Platform and Laminar Ice ». Highlights in Science, Engineering and Technology 72 (15 décembre 2023) : 480–86. http://dx.doi.org/10.54097/aey9bw92.
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Over the years, the development of the Arctic region has been increasingly emphasized, and the research and development of offshore platforms has become a research hotspot for many countries. Among them, all kinds of platform equipment used in the polar region must consider the special conditions when operating in extreme environments. For the floating ice-resistant marine platforms, the calculation of ice load is of considerable importance and value for the applicability and reliability design. In this article, the Kulluk platform has been chosen for the study. The interactions between the structure and the sea ice, such as collision and extrusion, are numerically simulated through the finite element method. In this paper we will explain how to calculate the ice loads acting on the floating platform and the specific loads. By setting the real scale in the program, the maximum correspondence with the real situation can be achieved. Subsequently, the numerical simulation values were analyzed and compared with the actual situation and empirical formulas to verify the reliability of the numerical simulation. The applicability of the Kulluk platform model to the problem of interaction with the leveling ice has been validated.
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Sohaimi, Asrul Khairi, Anwar P. P. Abdul Majeed et Jamaluddin Mahmud. « Preliminary Numerical Analysis of a Platform Structure ». Applied Mechanics and Materials 680 (octobre 2014) : 280–83. http://dx.doi.org/10.4028/www.scientific.net/amm.680.280.
Texte intégralRésumé :
Finite element analysis (FEA) has become an increasingly important tool in evaluating structural performance of platforms. This includes the use of this tool to perform strength, stability checks, optimisation of structural design upon subjected to design loads as well as to perform failure investigation of platforms upon subjected to special loading conditions such as impacts. Traditionally, small and medium enterprises utilises laboratory (physical) testing and heuristic experience to fabricate and test the platforms, nonetheless this approach is deemed too time consuming and cost demanding. Therefore, this study aims at reconstructing the actual design based on engineering drawings as well as performing stress analysis by means of a commercial FEA software package, ANSYS v14.0 by investigating the effects of two distinct loading impacts on a mild steel platform. The maximum stress and maximum displacement values obtained via the FEA simulation was then compared with values obtained via theoretical computation. The results obtained via the FEA simulation was found to be in good agreement with the exact solution. The present study is non-trivial as it contributes towards the knowledge in the design and optimisation of complex steel structures.
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Guglielmelli, Alexa, Giuseppe Nicoletta, Liliana Valente, Giovanna Palermo et Giuseppe Strangi. « Numerical Modeling of 3D Chiral Metasurfaces for Sensing Applications ». Crystals 12, no 12 (12 décembre 2022) : 1804. http://dx.doi.org/10.3390/cryst12121804.
Texte intégralRésumé :
Sensitivity and specificity in biosensing platforms remain key aspects to enable an effective technological transfer. Considerable efforts have been made to design sensing platforms capable of controlling light–matter interaction at the nanoscale. Here, we numerically investigated how a 3D out-of-plane chiral plasmonic metasurface can be used as a key element in a sensing platform, by exploiting the variation in the plasmonic and lattice modes as a function of the refractive index of the surrounding medium. The results indicate that chiral metasurfaces can be used to perform sensing, by detecting the refractive index change with a maximum sensitivity of 761 nm/RIU. The metasurface properties can be suitably designed to maximize the optical response in terms of the shift, modulated by the refractive index of the analyte molecules. Such studies can pave the way for engineering and fabricating highly selective and specific chiral metasurface-based refractive index sensing platforms.
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Yao, Zhi, Fali Huo, Yuanyao Zhu, Chenxuan Tang, Kunqiao Jia, Dong Li et Yong Ma. « Experimental and Numerical Investigation on Slamming Mechanism of a Mooring Column-Stabilised Semi-Submersible ». Processes 11, no 3 (28 février 2023) : 725. http://dx.doi.org/10.3390/pr11030725.
Texte intégralRésumé :
Semi-submersible offshore platforms play a vital role in deep-sea energy exploitation. However, the vast waves threaten the platform’s operation, usually leading to severe consequences. It is essential to study the wave-slamming mechanism of offshore platforms under extreme wave conditions. Existing research usually simplifies the offshore platform slamming problem. This paper establishes a model of a semi-submersible platform and a flexible mooring system in a numerical pool by means of the computational fluid dynamics (CFD) method. The distribution and the sensitivity of the slamming load on columns and deck in waves were investigated, and the model was verified through the basin test. Firstly, based on the Reynolds-averaged Navier–Stokes model, this study considers the volume-of-fluid method to track the free liquid level. After the column and floating body grid are locally refined, the slamming load under extreme regular wave impact is measured by measuring points on the column and deck. Then, the slamming experiment of the semi-submersible was carried out in the basin. The experiment model with a scale ratio of 1:100 was established to investigate the platform’s motion and slamming loads under extreme regular and irregular waves. The findings indicate that the slamming load at the junction of the column and deck significantly increased, exhibiting a ‘double-peak’ phenomenon at the middle of the column. The maximum pressure of slamming at the top of the column demonstrated an inverted U-shaped distribution, with negative pressure occurring after the peak value, indicating a pronounced oscillation effect.
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Mou, Shandong, Kexin Zhong et Yamin Ma. « Regulating the Big Data-Based Discriminatory Pricing in Platform Retailing : A Tripartite Evolutionary Game Theory Analysis ». Mathematics 11, no 11 (5 juin 2023) : 2579. http://dx.doi.org/10.3390/math11112579.
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Nowadays, with the rapid development of the platform economy, Big Data-based Discriminatory Pricing (BDDP) has become a common phenomenon in which big data and algorithms are applied to excessively seize consumer surplus and thus damage the rights and interests of consumers. This work aims to explore the equilibrium strategies of the consumers, the government, and the service platform and discuss factors affecting the BDDP practice of the service platforms. This study constructs a tripartite evolutionary game model among consumers, service platforms, and the government. Two evolutionary equilibrium strategies are derived and validated using simulation. Numerical experiments are conducted using MATLAB to reveal players’ evolutionary stability strategies under various settings. The study shows that (1) the strategies of the government and the platform always influence each other, (2) a reasonable adjustment of tax rate helps regulate the platform’s behavior, and (3) the proportion of consumers who switch the platform after they realize themselves suffering BDDP is an important factor influencing platform’s strategy. This study lastly summarizes the managerial insights for dealing with the platform’s BDDP behavior and safeguarding consumers’ rights from the perspectives of macro-regulation and privacy data protection. The conclusions of this study can help promote the high-quality development of the platform economy.
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Wang, Yongliang, et Xingchen Zhang. « Calculating the Maximum Assembling on Nested Routing Platforms of Urban Rail Transit Line ». Journal of Systems Science and Information 2, no 4 (25 août 2014) : 372–84. http://dx.doi.org/10.1515/jssi-2014-0372.
Texte intégralRésumé :
Abstract The maximum assembling for some period on nested routing platforms of urban rail transit line were calculated by trend analysis method. Based on influencing factors of maximum assembling on platform, relative hypotheses were given. Platforms were divided to eight types by relations between platform and routing train. Interaction of passenger, train and platform, assembling change process, and calculation frames of maximum assembling on different type platforms carried out to be maximum assembling were concluded by trend analysis method. The numerical example application revealed that trend analysis method to calculate maximum assembling on nested routing platforms is feasible, and the final results by trend analysis method are more accurate than by one of codes for design of metro.
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Wu, Yuming, Aohua Tian et Hengxing Lan. « Comparisons of Dynamic Landslide Models on GIS Platforms ». Applied Sciences 12, no 6 (17 mars 2022) : 3093. http://dx.doi.org/10.3390/app12063093.
Texte intégralRésumé :
Numerical simulation is one of the methods to assess landslide movement processes, which is beneficial for engineering design and urban planning. With the development of computer technology, GIS has gradually become the mainstream platform for landslide simulation due to data availability and algorithm integrability. However, the dynamic processes of landslides are complicated, which makes integration difficult on GIS platforms. Some assumptions are applied to simplify these dynamic processes and solve this problem. Generally, there are two main types of numerical models on GIS platforms: models based on the Eulerian description and models based on the Lagrangian description. Case studies show that Eulerian models are suitable for flow-like movement, and Lagrangian models are suitable for discrete rigid bodies movement. Different models face different problems: the Eulerian-based models show numerical diffusion and oscillation, and the Lagrangian-based model needs to consider complicated shear and collision processes. In addition, the 3-D model can describe more details in the z-direction, while the depth-averaged model can obtain a reasonable range of motion, depth, and speed quickly. From the view of numerical simulation, inappropriate models, assumptions, and numerical schemes will produce errors. The landslide type refers to several forms of mass wasting associated with a wide range of ground movements, which guides establishing dynamic models and numerical schemes on GIS platforms and helps us obtain results accurately.
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Tian, Aohua, Yuming Wu et Xing Gao. « A 3D Two-Phase Landslide Dynamical Model on GIS Platform ». Applied Sciences 14, no 2 (9 janvier 2024) : 564. http://dx.doi.org/10.3390/app14020564.
Texte intégralRésumé :
The landslide dynamics model is one of the methods for evaluating landslide motion processes, contributing to disaster prevention and mitigation. With the advancement of science and technology, GIS has become the mainstream platform for landslide simulation. However, the three-dimensional movement of landslides is intricate, leading to a lack of methods for three-dimensional landslide numerical simulation on GIS platforms. In this paper, we propose a three-dimensional, two-phase landslide dynamics model. Through the proposed solution, three-dimensional modeling and numerical simulation of landslides can be achieved on GIS platforms. Simultaneously, drawing inspiration from the SPH kernel functions, we visualize the results of the three-dimensional model on the GIS platform. Simulation of the Yigong landslide demonstrates that our solution can realize three-dimensional landslide simulation on the GIS platform. Our model adeptly captures numerous details in the landslide motion process. However, constrained by the inherent limitations of the three-dimensional model, the model results are susceptible to numerical oscillations and diffusion, with the accuracy of the model being controlled by grid partitioning.
Thèses sur le sujet "Numerical platforms"
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Ozec, Mustafa Onur. « Direction Finding Performance Of Antenna Arrays On Complex Platforms Using Numerical Electromagnetic Simulation Tools ». Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613740/index.pdf.
Texte intégralRésumé :
An important step for the design of direction finding systems is the performance evaluation
using numeric electromagnetic simulation tools. In this thesis, a method is presented for both
modeling and simulation in a numeric electromagnetic simulation tool FEKO. The method
relies on the data generated by FEKO. The data is then processed by correlative interferometer
algorithm. This process is implemented in a MATLAB environment. Different types of
antenna arrays including dipole, monopole and discone antennas are used. The antenna arrays
are mounted on a UAV and SUV in order to see the platform effects. The direction finding
performance is evaluated for different scenarios. It is shown that the presented approach is an
effective tool for understanding the direction finding characteristic of antenna arrays.
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Khoueiry, Nicole. « Study of granular platforms behaviour over soft subgrade reinforced by geosynthetics : Experimental and numerical approaches ». Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEI027.
Texte intégralRésumé :
Les géosynthétiques sont utilisés depuis les années 70 dans le renforcement des plateformes granulaires reposant sur des sols de faible portance pour des applications de routes non revêtues. La complexité des mécanismes développés et la diversité des produits de renforcement nécessitent encore d’étudier ces plateformes renforcées. Un essai au laboratoire permettant de tester des plateformes à échelle réelle a été développé. Une plateforme granulaire non revêtue reposant sur un sol de faible portance a été reproduite. Un protocole de mise en place de ce sol a été élaboré pour assurer son homogénéité et la répétabilité des essais. Une instrumentation spécifique a été développée pour collecter le maximum de mesures utiles pour l’interprétation du transfert de charge et du comportement des géogrilles utilisées. Trois types de géogrille ont été testées : une géogrille extrudée et deux géogrilles tricotées de rigidité différente. Après de nombreux essais de faisabilité, dix essais ont été effectués sous un chargement cyclique sur plaque circulaire, la plateforme testée a été placée dans un banc d’essai de 1,8 m de large, 1,9 m de long et 1,1 m de haut. Sur la base du même protocole de mise en œuvre, des essais de circulation avec un Simulateur Accélérateur de Traffic (SAT) ont été effectués. Ce simulateur a été spécifiquement conçu et construit pour cette application. Pour ces essais, la plateforme testée a été placée dans le banc d’essai allongé à 5 m. La plateforme a été soumise à deux types de sollicitations : un chargement cyclique sur plaque et un chargement de circulation. Des essais de répétabilité ont permis de vérifier le protocole mis en place. A partir des essais, plusieurs observations ont pu être faites sur le comportement des plateformes granulaires, le sol peu porteur, et sur l’efficacité du renforcement. De plus, ces essais ont permis de montrer que le chargement de circulation est beaucoup plus endommageant que le chargement sur plaque. Parallèlement à ces essais, un modèle numérique a été développé en se basant sur la méthode des différences finies avec le logiciel FLAC 3D. Cette modélisation a permis de prédire le comportement de la plateforme sous le premier chargement de plaqueGeosynthetics were used since 1970 in the base course reinforcement supported by soft subgrade in unpaved road application. The various factors and parameters influencing the dominant mechanism and its relative contribution on the platform improvement explain the need of more investigations in this topic. In this research work, large-scale laboratory test was developed to study the reinforcement contribution in the unpaved road improvement. Therefore, an unpaved platform was built of 600 mm of artificial subgrade supporting a base course layer. A detailed experimental Protocol was established regarding the soil preparation, the installation and the soils compaction procedure to reproduce the site conditions and insure the platform repeatability for each test. Three geosynthetics were tested first under a cyclic plate load test. Cyclic load was performed on the prepared platform, with a maximum load of 40 kN resulting in a maximum applied pressure of 560 kPa. The platform was subjected to 10,000 cycles with a frequency of 0.77 Hz. An advanced and complete soil instrumentation was provided in order to collect the maximum data needed for thorough analysis. Quality control tests were performed before each test to verify the soil layers homogeneity and properties. Two base course thicknesses were tested under this test condition, 350 and 220 mm. Once the developed protocol was confirmed under the circular plate load tests, further tests using the Simulator Accelerator of Traffic (SAT) were performed. Indeed, the laboratory prepared platform was placed in a larger box of 1.8 m in large, 5 m in length and 1.1 m in height. The prepared platform was subjected to two solicitations: a particular plate and traffic load. The Simulator Accelerator of Traffic was developed specially for this application. A machine that simulates the traffic load under an effective length of 2 m and a velocity of 4 km/h. The two areas were instrumented: the area under the circulation load, and the area under the plat load, located aside. In addition, a numerical model based on the differential element method using FLAC 3D was developed. The model simulated the circular plate load test with the same platform configuration under monotonic load. The results were compared to the first monotonic load applied on the rigid plate experimentally
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Frazer, Miles. « Advances in understanding the evolution of diagenesis in Carboniferous carbonate platforms : insights from simulations of palaeohydrology, geochemistry, and stratigraphic development ». Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/advances-in-understanding-the-evolution-of-diagenesis-in-carboniferous-carbonate-platforms-insights-from-simulations-of-palaeohydrology-geochemistry-and-stratigraphic-development(9a1caa9d-6f16-472a-8b38-42aca657a9b9).html.
Texte intégralRésumé :
Carbonate diagenesis encapsulates a wide range of water rock interactions that can occur within many environments and act to modify rock properties such as porosity, permeability, and mineralogical composition. These rock modification processes occur by the supply of reactant-laden fluids to areas where geochemical reactions are thermodynamically and kinetically favoured. As such, understanding the development of diagenesis requires an understanding of both palaeohydrology and geochemistry, both of which have their own complexities. However, within geological systems, both the conditions that control fluid migration and the distribution of thermodynamic conditions can change through time in response to external factors. Furthermore, they are often coupled, with rock modification exercising a control on fluid flow by altering the permeability of sediments. Numerical methods allow the coupling of multiple complex processes within a single mathematical formulation. As such, they are well suited to investigations into carbonate diagenesis, where multiple component subsystems interact. This thesis details the application of four separate types of numerical forward modelling to investigations of diagenesis within two Carboniferous carbonate platforms, the Derbyshire Platform (Northern England) and the Tengiz Platform (Western Kazakhstan). Investigations of Derbyshire Platform diagenesis are primarily concerned with explaining the presence of Pb-mineralisation and dolomitisation observed within the Dinantian carbonate succession. A coupled palaeohydrology and basin-development simulation and a series of geochemical simulations was used to investigate the potential for these products to form as a result of basin-derived fluids being driven into the platform by compaction. The results of these models suggest that this mechanism is appropriate for explaining Pb-mineralisation, but dolomitisation requires Mg concentrations within the basin-derived fluids that cannot be attained. Geothermal convection of seawater was thus proposed as an alternative hypothesis to explain the development of dolomitisation. This was tested using an advanced reactive transport model, capable of considering both platform growth and dolomitisation. The results of this suggests that significant dolomitisation may have occurred earlier on in the life of the Derbyshire Platform than has previously been recognised. An updated framework for the development of diagenesis in the Derbyshire Platform is proposed to incorporate these new insights. The Tengiz platform forms an important carbonate oil reservoir at the northeastern shore of the Caspian Sea. The effective exploitation of any reservoir lies in an understanding of its internal distributions of porosity and permeability. Within carbonate systems, this is critically controlled by the distribution of diagenetic products. A model of carbonate sedimentation and meteoric diagenesis is used to produce a framework of early diagenesis within a sequence stratigraphic context. The studies mentioned above provide a broad overview of the capabilities and applicability of forward numerical models to two data-limited systems. They reveal the potential for these methods to guide the ongoing assessment and development of our understanding of diagenetic systems and also help identify key questions for the progression of our understanding in the future.
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Albaiz, Abdulaziz (Abdulaziz Mohammad). « MPI-based scalable computing platform for parallel numerical application ». Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/95562.
Texte intégralRésumé :
Thesis: S.M., Massachusetts Institute of Technology, Computation for Design and Optimization Program, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references (page 61).
Developing parallel numerical applications, such as simulators and solvers, involves a variety of challenges in dealing with data partitioning, workload balancing, data dependencies, and synchronization. Many numerical applications share the need for an underlying parallel framework for parallelization on multi-core/multi-machine hardware. In this thesis, a computing platform for parallel numerical applications is designed and implemented. The platform performs parallelization by multiprocessing over MPI library, and serves as a layer of abstraction that hides the complexities in dealing with data distribution and inter-process communication. It also provides the essential functions that most numerical application use, such as handling data-dependency, workload-balancing, and overlapping communication and computation. The performance evaluation of the parallel platform shows that it is highly scalable for large problems.
by Abdulaziz Albaiz.
S.M.
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Alleau, Thibaut. « Development of a numerical platform to model the mitral valve ». Thesis, Compiègne, 2021. http://www.theses.fr/2021COMP2649.
Texte intégralRésumé :
L’insuffisance mitrale est la valvulopathie mondiale la plus fréquente avec une prévalence de 2%. Lorsque le patient n’est pas en mesure d’être opéré à cœur ouvert, un implant percutané est utilisé pour aider la fermeture des feuillets. Le seul implant actuellement disponible est basé sur la réparation bord à bord de la valve mitrale. Il réduit le reflux vers l’oreillette lors de la systole, mais n’est pas adapté pour les patients souffrant d’insuffisance mitrale fonctionnelle, chez qui la pathologie provient du ventricule et non des éléments de la valve. L’objectif de la thèse est de fournir une plateforme numérique permettant d’aider au développement d’un implant adapté pour ces patients. Plusieurs géométries de valve ont été réalisées au moyen d’un modèle paramétrique, en utilisant des données anatomiques. La dynamique de la valve a été modélisée avec le logiciel ADINA par des simulations éléments finis en grandes déformations. Des modèles structurels de la valve ont permis de représenter la fermeture de la valve sous une pression uniforme. Les lois de comportement de matériaux ont été développé dans le but d’obtenir une fermeture réaliste de la valve. Cela a nécessité la prise en compte de l’hyperélasticité et de l’anisotropie des tissus. Des pathologies valvulaires, telles que la dilatation de l’anneau mitrale ou la rupture des cordages tendineux ont été modélisées, et plusieurs méthodes ont été testées pour y apposer des systèmes médicaux. En utilisant une description ALE et un couplage monolithique, les interactions fluide-structure ont été simulées pour une valve mitrale bi-dimensionnelle. La fermeture hermétique de la valve pendant la systole a pu être reproduite et l’ouverture de la valve étudiée pendant la diastole. La plateforme numérique développée permet de modéliser la fonction de la valve mitrale et peut être utilisée pour aider au développement d’un implant mitral grâce au modèle paramétrique reproduisant différentes géométries de valve et aux lois matériaux anisotropes. Une perspective reste la création d’un modèle 3D des interactions fluide-structure de la valve mitraleMitral insufficiency is the first valvular disease worldwide, with a 2% prevalence. When open-heartsurgery is impossible for the patient, surgeons use percutaneous devices to help the mitral leaflets coapt. However, the only device currently available is based on the edge-to-edge mitral valve repair technique. This type of implant is not adapted for patients suffering from functional mitral insufficiency, where the ventricle is responsible for the lack of coaptation of the leaflets. This thesis aims to provide a numerical platform to help the development of a mitral valve implant adapted for those patients. Several mitral valve geometries were created from a parametric model using anatomical measurements. Finite element simulations of the mitral valve were performed using ADINA to determine the valve closure under constant pressure. Several material models were developed in large strain and large deformation to model the valve closure accurately. Pathological behaviour such as annulus dilatation and chordae rupture were modelled, and several methods were tested to implement medical devices. Fluid-structure interaction of a 2D mitral valve was obtained using an ALE description and a monolithic coupling approach. Both the systole and the diastole were reproduced and studied, and the hermetic seal of the valve was detailed. The numerical platform developed is suited to model mitral valve function and can be used to help the development of mitral implants. In addition, the parametric geometry model and the anisotropic material model will be useful to depict with realism the valve function. A 3D fluid-structure interaction of the mitral valve could be developed
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Jouan, Marine. « La construction sociale du marché du financement participatif en France ». Electronic Thesis or Diss., Paris, ENST, 2017. http://www.theses.fr/2017ENST0052.
Texte intégralRésumé :
Depuis la fin des années 2000, les plateformes de financement participatif se développent en France avec la promesse d’une relation directe, désintermédiée, entre demandeurs de financement et financeurs, en facilitant l’accès aux fonds pour des porteurs de projet et en permettant aux Français de financer les projets de leur choix. Cette thèse vise à étudier ce phénomène à partir d’une enquête combinant observation ethnographique et entretiens menés auprès des différents acteurs qui se sont organisés pour faire exister et développer ce secteur d’activité. L’enquête montre que l’institutionnalisation du financement participatif en France résulte d’une action collective impliquant des professionnels du secteur, des représentants des pouvoirs publics, des partenaires de plateformes et des médias. Alors que les plateformes défendent un modèle d’auto-organisation et d’autonomie, il apparaît que le développement des plateformes n’aurait pas été possible sans l’intervention des pouvoirs publics qui ont créé un cadre juridique favorable au financement participatif, au nom d’une volonté de faire évoluer le rapport des Français à leur épargne et d’amener ces derniers à contribuer à la santé économique des entreprises dans un contexte de crise. L’enquête montre aussi que par-delà l’extrême hétérogénéité des trois modèles majoritaires de financement participatif étudiés (don/contrepartie, prêt et capital), un effort collectif est fait pour mettre en valeur les points communs et gommer l’hétérogénéité des secteurs concernés (d’un côté le monde de la création culturelle, de l’autre le monde de la finance). Les plateformes, en tant que dispositifs socio-techniques, cherchent à se présenter comme des instruments neutres qui favoriseraient un appariement naturel entre des demandeurs de fonds et des financeurs. Cette recherche montre au contraire que l’essor de ce modèle de financement est le fruit d’un travail marchand mené par les professionnels du secteur pour recruter deux types d’usagers sur leur plateforme : des demandeurs de fonds d’un côté et des financeurs de l’autre. L’enquête montre les arbitrages opérés par les plateformes entre une logique de volume et une logique de qualité. Pour réduire le risque, les plateformes mettent en place des systèmes de qualification et de sélection des projets, souvent importés de la finance traditionnelle, qui entrent en contradiction avec les discours de démocratisation de l’accès au financement. Dans leurs efforts de développement, elles cherchent aussi à nouer des relations avec les acteurs traditionnels du monde de la finance. Ce faisant elles réintroduisent de nouveaux intermédiaires qui viennent complexifier la relation entre demandeurs de fonds et financeursSince the end of the 2000s, crowdfunding platforms have been developing in France with the promise of a direct and disintermediated relationship between project owners and funders, facilitating access to funds for project owners and allowing French Internet users to fund projects of their choice. This PhD dissertation studies this phenomenon by combining ethnographic observation and interviews with various actors who have participated in the development of this activity. The research shows that the institutionalization of crowdfunding in France stems from a collective action involving industry professionals, representatives of public authorities, platform partners, and the media. While platforms defend a model of self-organization and autonomy, it appears that their development would not have been possible without the intervention of public authorities, who have created a favorable legal framework to crowdfunding, in order to change the relationship of the French population with its savings and to encourage the contribution to the economic health of new firms in a context of crisis. The study also shows that, despite the extreme heterogeneity of the three majority crowdfunding models studied (reward-based, lending-based, and equity-based), there is a collective effort to highlight common characteristics and to blur the heterogeneity of the sectors (on the one hand the world of cultural creation, on the other the world of finance). Platforms, as socio-technical devices, seek to present themselves as neutral instruments that favor a natural match between fund seekers and funders. This research shows that actually the growth of this financing model is the result of a market labor carried out by professionals in the sector to bring two types of users on their platform: the fund-seekers on one side and the funders on the other. The research also shows that the platforms strategic decisions try to balance out quantity and quality of projects. To reduce risks, platforms put in place qualification and project selection processes, often imported from traditional finance - contradicting the idea of democratization of access to funding. In their development efforts, they also seek to build relationships with traditional players from the world of finance. In doing so, they reintroduce new intermediaries that complicate the relationship between fund-seekers and funders
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Zareh, Bannad Kouki Mehrdad. « Development of a novel numerical platform for the assessment of atherosclerotic plaque vulnerability ». Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/57028.
Texte intégralRésumé :
It is well known that mechanics of atherosclerotic plaques significantly depend on plaque geometry, location, composition, and loading conditions. Computational studies have shown great potential to characterize this mechanical behavior. Different types of plaque morphologies and mechanical properties have been used in two-dimensional (2D) and three-dimensional (3D) computational platforms mostly based on the finite element method to estimate the stability of rupture-prone plaques and detect their locations.
It is well-known that 2D models are not reliable as they do not provide a consistent assessment on the vulnerability of plaques and are highly erroneous. 3D models offer a more effective evaluation but creating 3D models to be further assessed by computational means such as the finite element method is time-consuming. However, 2D models are easier to develop and are less time-consuming to assess. In this thesis, a novel computational platform was developed by which the plaque vulnerability is assessed using only 2D plaque models. We develop idealistic 2D models and their corresponding idealistic 3D models. The idealistic 3D models resemble the worst- and best- case scenarios for each 2D model. Using these 3D idealistic models, a standard error (SE) is estimated and then added to the peak stress values calculated earlier using 2D models. These SEs are also used to assess the probability of plaque stability. In this platform, the effect of viscoelasticity and anisotropy of the plaque composition is taken into consideration and the transmural pressure considered is similar to that of physiological conditions. Also, for the first time heart rate (HR) was introduced as a major predictor of vulnerable plaque ruptures that should be taken into account while mechanics of plaques is studied. A tunable viscoelastic constitutive material model was developed for the fibrous cap tissue in order to calculate the peak cap stress (PCS) in normal physiological conditions while HR changes from 60 bpm to 150 bpm. A critical discussion on stress distribution in the fibrous cap area is made with respect to HR. Results strongly suggest the viscoelastic properties of the fibrous cap tissue and HR together play a major role in the estimation of the PCS values. The results obtained in this thesis may provide a better understanding of the mechanics of atherosclerosis.Applied Science, Faculty of
Engineering, School of (Okanagan)
Graduate
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Nguyen, Thi Minh Tuyen. « Taking architecture and compiler into account in formal proofs of numerical programs ». Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00710193.
Texte intégralRésumé :
On some recently developed architectures, a numerical program may give different answers depending on the execution hardware and the compilation. These discrepancies of the results come from the fact that each floating-point computation is calculated with different precisions. The goal of this thesis is to formally prove properties about numerical programs while taking the architecture and the compiler into account. In order to do that, we propose two different approaches. The first approach is to prove properties of floating-point programs that are true for multiple architectures and compilers. This approach states the rounding error of each floating-point computation whatever the environment and the compiler choices. It is implemented in the Frama-C platform for static analysis of C code. The second approach is to prove behavioral properties of numerical programs by analyzing their compiled assembly code. We focus on the issues and traps that may arise on floating-point computations. Direct analysis of the assembly code allows us to take into account architecture- or compiler-dependent features such as the possible use of extended precision registers. It is implemented above the Why platform for deductive verification
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Tchorowski, Leo A. « Sparse-Constrained Equivalent Element Distribution Method to Represent Measured Antenna Data in Numerical Electromagnetics Codes ». The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1582877220383629.
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Giovacchini, Valentina <1992>. « Development of a numerical platform for the modeling and optimal control of liquid metal flows ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2022. http://amsdottorato.unibo.it/10269/1/tesi_phd_giovacchini.pdf.
Texte intégralRésumé :
The main purpose of this work is to develop a numerical platform for the turbulence modeling and optimal control of liquid metal flows.
Thanks to their interesting thermal properties, liquid metals are widely studied as coolants for heat transfer applications in the nuclear context. However, due to their low Prandtl numbers, the standard turbulence models commonly used for coolants as air or water are inadequate.
Advanced turbulence models able to capture the anisotropy in the flow and heat transfer are then necessary. In this thesis, a new anisotropic four-parameter turbulence model is presented and validated. The proposed model is based on explicit algebraic models and solves four additional transport equations for dynamical and thermal turbulent variables. For the validation of the model, several flow configurations are considered for different Reynolds and Prandtl numbers, namely fully developed flows in a plane channel and cylindrical pipe, and forced and mixed convection in a backward-facing step geometry.
Since buoyancy effects cannot be neglected in liquid metals-cooled fast reactors, the second aim of this work is to provide mathematical and numerical tools for the simulation and optimization of liquid metals in mixed and natural convection. Optimal control problems for turbulent buoyant flows are studied and analyzed with the Lagrange multipliers method. Numerical algorithms for optimal control problems are integrated into the numerical platform and several simulations are performed to show the robustness, consistency, and feasibility of the method.
Livres sur le sujet "Numerical platforms"
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Chekanov, Sergei V. Numeric Computation and Statistical Data Analysis on the Java Platform. Cham : Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-28531-3.
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Søren, Larsen, Fiedler Franz, Borrell Peter et GSF-Forschungszentrum für Umwelt und Gesundheit, dir. Exchange and transport of air pollutants over complex terrain and the sea : Field measurements and numerical modelling : ship, ocean platform and laboratory measurements. Berlin : Springer, 2000.
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L, Di Vito Ben, et Langley Research Center, dir. Formal design and verification of a reliable computing platform for real-time control : Phase 2 results. Hampton, Va : National Aeronautics and Space Administration, Langley Research Center, 1992.
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Butler, Ricky W. Formal design and verification of a reliable computing platform for real-time control : Phase 3 results. Hampton, Va : National Aeronautics and Space Administration, Langley Research Center, 1994.
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(Editor), Alan R. Kimmel, et Brian Oliver (Editor), dir. DNA Microarrays Part A : Array Platforms & Wet-Bench Protocols, Volume 410 (Methods in Enzymology). Academic Press, 2006.
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(Editor), Alan R. Kimmel, et Brian Oliver (Editor), dir. DNA Microarrays Part A : Array Platforms & Wet-Bench Protocols, Volume 410 (Methods in Enzymology). Academic Press, 2006.
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Chekanov, Sergei V. Numeric Computation and Statistical Data Analysis on the Java Platform. Springer London, Limited, 2016.
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Chekanov, Sergei V. Numeric Computation and Statistical Data Analysis on the Java Platform. Springer International Publishing AG, 2018.
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Chekanov, Sergei V. Numeric Computation and Statistical Data Analysis on the Java Platform (Advanced Information and Knowledge Processing). Springer, 2016.
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Ramsay, Stephen. ’Patacomputing. University of Illinois Press, 2017. http://dx.doi.org/10.5406/illinois/9780252036415.003.0005.
Texte intégralRésumé :
This chapter surveys some of the newer text-analytical tools—claiming them, unabashedly, as potential instruments of algorithmic criticism. It demonstrates that the degree to which the text-analysis systems WordHoard, Text Analysis Portal for Research (TAPoR), HyperPo, and MONK (Metadata Offer New Knowledge) show the way forward, they do so largely by embracing the contingencies that once threatened the discipline of rhetoric, but that, like rhetoric, may come to form the basis for new kinds of critical acts. In an age when the computer itself has gone from being a cold arbiter of numerical facts to being a platform for social networking and self-expression, one may well wonder whether those new kinds of critical acts are in fact already implicit in the many interfaces that seek only to facilitate thought, self-expression, and community.
Chapitres de livres sur le sujet "Numerical platforms"
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Emad, Nahid, Olivier Delannoy et Makarem Dandouna. « Numerical Library Reuse in Parallel and Distributed Platforms ». Dans Lecture Notes in Computer Science, 271–78. Berlin, Heidelberg : Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-19328-6_26.
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Kurowski, Krzysztof. « Challenges for Future Platforms, Services and Networked Applications ». Dans Notes on Numerical Fluid Mechanics and Multidisciplinary Design, 19–30. Cham : Springer International Publishing, 2012. http://dx.doi.org/10.1007/978-3-642-31095-9_2.
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Barnat, Wiesław, et Aleksander M. Nawrat. « Numerical and Experimental Study of Influence of IED Blast on Crew Inside Vehicle ». Dans Innovative Control Systems for Tracked Vehicle Platforms, 227–41. Cham : Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-04624-2_14.
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Abou Chaz, N., P. Villard, C. Silvani, L. Briançon, A. Nancey et A. Abdelouhab. « Numerical study of the geosynthetics reinforced platforms laid over soft subgrade soil ». Dans Geosynthetics : Leading the Way to a Resilient Planet, 1078–84. London : CRC Press, 2023. http://dx.doi.org/10.1201/9781003386889-134.
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Yoshioka, Keita, Mathias Nest, Daniel Pötschke, Amir Shoarian Sattari, Patrick Schmidt et David Krach. « Numerical Platform ». Dans GeomInt–Mechanical Integrity of Host Rocks, 63–95. Cham : Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-61909-1_3.
Texte intégralRésumé :
AbstractAn essential scientific goal of the GeomInt project is the analysis of potentials and limitations of different numerical approaches for the modelling of discontinuities in the rocks under consideration in order to improve the understanding of methods and their synergies with regard to theoretical and numerical fundamentals. As numerical methods, the “Lattice Element Method” (LEM), the non-continuous discontinuum methods “Discrete Element Method” (DEM), the “Smoothed Particle Hydrodynamics” (SPH), the “Forces on Fracture Surfaces” (FFS) as well as the continuum approaches “Phase-Field Method” (PFM), “Lower-Interface-Method” (LIE), “Non-Local Deformation” (NLD) and the “Hybrid-Dimensional Finite-Element-Method” (HDF) will be systematically investigated and appropriately extended based on experimental results (Fig. 3.1).
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Lu, Xingya, Peng Li, Shengrui Su, Haibo Jiang et Fu Dong. « Optimization Design of Sand and Loess High Slope Based on Combination of Wide and Narrow Platfom——A Case Study of a High Slope in Yulin City ». Dans Lecture Notes in Civil Engineering, 147–61. Singapore : Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-2532-2_13.
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AbstractDue to the limited land resources available for engineering construction in Northern Shaanxi, engineering activities such as mineral resources development, basic engineering construction, slope reduction and building houses, and farming are often accompanied by the formation of a large number of Manually Excavated high slopes. Effective high slope design can reduce the waste of land resources, mitigate the damage to the natural environment, and reduce the project cost to a certain extent. Therefore, this paper takes a high sand loess slope in Yulin City, Shaanxi Province as an example, through field investigation, system theoretical analysis and numerical simulation calculation, comprehensively considering the anti scouring property, overall stability and excavation volume of the slope, the design scheme that meets the requirements and consumes the least capital is compared and selected, so as to obtain the optimal slope shape. The conclusion shows that the optimal single slope height of sand loess high slope in Northern Shaanxi is 7–8 m, and the slope ratio is 1:0.75. The setting of wide platform can change the stress distribution of high slope and weaken the continuity of effective plastic strain. The optimal slope shape of the high side slope includes the single slope of 8 m, the slope ratio of 1:0.75, the narrow platform of 3 m wide, 3 wide platforms are arranged, the location of ③④⑤, the width of 10 m, and the excavation volume of 696 m3 (per linear meter).
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Pham, Dung Ngoc. « Profiling General-Purpose Fast Multipole Method (FMM) Using Human Head Topology ». Dans Brain and Human Body Modeling 2020, 347–81. Cham : Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-45623-8_21.
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AbstractIn this study, we characterize the performance of the fast multipole method (FMM) in solving the Laplace and Helmholtz equations. We use the FMM library developed by the group of Dr. L. Greengard. This version of the FMM algorithm is multilayer with no priori limit on the number of levels of the FMM tree, although, after about thirty levels, there may be floating point issues. A collection of high-resolution human head models is used as test objects. We perform a detailed analysis of the runtime and memory consumption of the FMM in a wide range of frequencies, problem sizes, and precisions required. Although we focus on two-manifold test cases, the results are generalizable to other topologies as well. The tests are conducted on both Windows and Linux platforms. The results obtained in this study can serve as a general benchmark for the performance of FMM. It can also be employed to pre-estimate the efficiency of numerical modeling methods (e.g., the boundary element method) accelerated by FMM.
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Beani, Egle, Elisabetta Colucci, Luigi La Riccia, Andrea Maria Lingua, Paolo Felice Maschio, Francesca Matrone, Alberto Possa et Ammj Traore. « The 3D Metric Survey for the Digital Cartographic Production to Support the Knowledge of the New Municipality of Mappano ». Dans The Urban Book Series, 153–68. Cham : Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-33894-6_12.
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AbstractThe complexity of the territories and cities is the genesis of the need to carry out spatial analyses, simulations of complex phenomena and urban planning, requiring an evolution of very large-scale numerical cartography. The representation of cities has not to ignore some essential aspects as well as: the three-dimensionality of the land and all its natural and artificial objects, the multi-scale of geometric and descriptive information to allow different levels of detail and granularity according to the operational purposes, and the interoperability, which enable sharing of map data among various stakeholders and applications for complex analysis. The outcome resulted in the evolution of traditional cartography into numerical cartography toward new instruments and applications such as digital twins. They constitute a virtual replica of physical, potential, and actual resources equivalent to objects, processes, people, places, infrastructures, systems, and devices related to the city and the territory. The case study selected for this research is the recent municipality of Mappano, in the metropolitan city of Turin. The methodology consists of a semiautomatic extraction of cartographic information and geometry essential for defining a digital twin. It has been developed investigating the existing Piedmontese regional geoportal (BDTRE) datasets and data models, and the Geographic Information System (GIS) standard specification for 3D city models, CityGML, mainly considering the first three levels of detail (LoD). The methodology and the resulting spatial data application have been validated by in-loco surveys and digital tools in GIS environment. The starting base map entities derived from a high-resolution acquisition from drone photogrammetry (UAV, Unmanned Aerial Vehicle, platforms have been adopted). The outputs of the aerial survey, orthophotos, and dense altimetric models (DTM, Digital Terrain Model and DSM, Digital Surface Model) were essential to extract various cartographic information.
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Cywiak, Moisés, et David Cywiak. « Stereoscopic Simple Numerical Method for Gravitational N-body ». Dans Multi-Platform Graphics Programming with Kivy, 231–56. Berkeley, CA : Apress, 2021. http://dx.doi.org/10.1007/978-1-4842-7113-1_14.
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Fujimoto, Noriyuki, et Shigeyoshi Tsutsui. « A Highly-Parallel TSP Solver for a GPU Computing Platform ». Dans Numerical Methods and Applications, 264–71. Berlin, Heidelberg : Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-18466-6_31.
Texte intégralActes de conférences sur le sujet "Numerical platforms"
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Simsek, Ergun, et Curtis R. Menyuk. « Designing silicon-germanium photodetectors with numerical optimization : the tradeoffs and limits ». Dans Active Photonic Platforms (APP) 2023, sous la direction de Ganapathi S. Subramania et Stavroula Foteinopoulou. SPIE, 2023. http://dx.doi.org/10.1117/12.2676137.
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Rees, P. E., Craig D. Stacey, Christopher Stace et Roy G. Clarke. « Numerical modelling of laser filamentation ». Dans High Power Lasers : Technology and Systems, Platforms, Effects III, sous la direction de David H. Titterton, Harro Ackermann et Willy L. Bohn. SPIE, 2019. http://dx.doi.org/10.1117/12.2538461.
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Scalora, Michael, Maria A. Vincenti, Domenico de Ceglia, Neset Akozbek, Laura Rodríguez-Suné, Jose F. Trull et Crina M. Cojocaru. « Retrieving linear and nonlinear optical dispersions of matter : Numerical ellipsometry of silicon and indium tin oxide nanolayers ». Dans Active Photonic Platforms XIII, sous la direction de Ganapathi S. Subramania et Stavroula Foteinopoulou. SPIE, 2021. http://dx.doi.org/10.1117/12.2594256.
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Nicolas, Riviere, Dupouy Paul-Édouard, Moussous Ahmed, Schilling Anita et Viala Erwan. « Numerical performance analysis applied to 3D-LiDAR tactical-mapping from aerial platforms ». Dans Applications of Lasers for Sensing and Free Space Communications. Washington, D.C. : Optica Publishing Group, 2022. http://dx.doi.org/10.1364/lsc.2022.lsm3c.3.
Texte intégralRésumé :
We describe the MATLIS software developed by ONERA to simulate 3D-LiDAR embedded on dynamic platforms. We present validation cases and a performance analysis study to design an original concept of 3D-LiDAR high altitude surveillance platform.
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Allheily, Vadim, Lionel Merlat et Gildas L'Hostis. « Experimental and numerical investigations of laser-induced thermal effects on composite materials ». Dans High Power Lasers : Technology and Systems, Platforms, Effects III, sous la direction de David H. Titterton, Harro Ackermann et Willy L. Bohn. SPIE, 2019. http://dx.doi.org/10.1117/12.2532258.
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Han, Seon. « Numerical Simulation of Ringing Response in Marine Platforms ». Dans ASME 2005 24th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2005. http://dx.doi.org/10.1115/omae2005-67503.
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In this paper, ringing phenomenon in a drag dominated marine platform is studied numerically using linear transverse and nonlinear coupled axial and transverse beam models. The effects of inertia, added mass, and relative velocity of the structure on ringing are investigated. It is found that, for the structure considered, inertia and added mass have little effect on ringing, while the relative velocity had a significant effect on its duration. The maximum ringing amplitude predicted by the nonlinear beam model is similar to that predicted by the linear beam model. When a smaller second impact is introduced, ringing stops when the nonlinear beam model is used.
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Xie, Kun, Wenguang Liu, Qiong Zhou, Hongmiao Zhao et Xiaojun Xu. « Numerical study of the measurement capability of quadriwave lateral shearing interferometry for multimode fiber laser (Conference Presentation) ». Dans High Power Lasers : Technology and Systems, Platforms, Effects, sous la direction de David H. Titterton, Harro Ackermann et Willy L. Bohn. SPIE, 2017. http://dx.doi.org/10.1117/12.2277995.
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Travanca, Joao, et Hong Hao. « Numerical Evaluation of Energy Absorption in Ship-Offshore Fixed Platform Collisions ». Dans ASME 2014 33rd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/omae2014-24118.
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Both the maritime traffic and the number of built offshore platforms have been continuously increasing over recent times. Among the structures built offshore, the fixed type constitutes the majority. The consequent diversity of plausible collision scenarios involving offshore platforms and passing ships must therefore consider aspects such as different ship size, different impact energy or different impact locations. For high energy collisions, large deformations are expected on both the platform and ship structures. It is expected that part of the energy absorption in the platform is confined to localized zones where plastic deformations take place, although the elastic strain energy may also be significant. For such impact problems, the amounts of strain energy in each structure are mainly dependent on the relative stiffness of the structures. By taking different ship and platform configurations as well as different contact points between the two bodies, different relative stiffness of the two structures can be tested in order to provide a clearer understanding of the dissipation of strain energy. The possible plastic deformation mechanisms are analyzed and simplified approaches are considered for prediction in comparison with the numerical results carried out by finite element analysis. Based on the results, some evaluations are made with respect to the code of practice in offshore platform design against ship impact.
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Gonsalves, Thiago, Eduardo Braga, Angela Nieckele et Wellington Campos. « NUMERICAL STUDY OF FLAMMABLE GASES DISPERSION IN OIL PLATFORMS ». Dans 26th International Congress of Mechanical Engineering. ABCM, 2021. http://dx.doi.org/10.26678/abcm.cobem2021.cob2021-2269.
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Malta, Edgard Borges, Marcos Cueva, Kazuo Nishimoto, Rodolfo Golc¸alves et Isai´as Masetti. « Numerical Moonpool Modeling ». Dans 25th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2006. http://dx.doi.org/10.1115/omae2006-92456.
Texte intégralRésumé :
The use of moonpools in offshore technology are normally related to the hull opening in drilling units with the objective to protect drilling equipment from environmental forces, and its design aims the minimum motion of the water inside the moonpool, avoiding water impacts when lowering an equipment. Several studies have been carried out to predict the water dynamics inside the moonpool. At most, analytical tools have been used with experimental results, to obtain a good evaluation of viscous effects. Another line of development uses the moonpools as a device to reduce motions of ships or oil platforms. In his context, the use of moonpools in monocolumn type platforms was studied during the development of the concept, through the partnership between PETROBRAS and University of Sa˜o Paulo–USP. An alternative that became viable in the last years is the use of numerical methods to evaluate potencial parameters, being only necessary simple experiments to obtains viscous data to complete the model. This work, that is a continuation of articles about the issue written before, intends to consolidate the calculation method of moonpool to monocolumn units.
Rapports d'organisations sur le sujet "Numerical platforms"
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Jha, Alok K. Spar Floating Platform : Numerical Analysis and Comparison with Data. Fort Belvoir, VA : Defense Technical Information Center, juin 1997. http://dx.doi.org/10.21236/ada390462.
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Levesque, Justine, Nathaniel Loranger, Carter Sehn, Shantel Johnson et Jordan Babando. COVID-19 prevalence and infection control measures at homeless shelters and hostels in high-income countries : protocol for a scoping review. York University Libraries, 2021. http://dx.doi.org/10.25071/10315/38513.
Texte intégralRésumé :
The COVID-19 pandemic has disproportionately impacted people experiencing homelessness. Homeless shelters and hostels, as congregate living spaces for residents with many health vulnerabilities, are highly susceptible to outbreaks of COVID-19. A synthesis of the research-to-date can inform evidence-based practices for infection, prevention, and control strategies at these sites to reduce the prevalence of COVID-19 among both shelter/hostel residents and staff. Methods: A scoping review in accordance with Arksey and O’Malley’s framework will be conducted to identify literature reporting COVID-19 positivity rates among homeless shelter and hostel residents and staff, as well as infection control strategies to prevent outbreaks in these facilities. The focus will be on literature produced in high-income countries. Nine academic literature databases and 11 grey literature databases will be searched for literature from March 2020 to July 2021. Literature screening will be completed by two reviewers and facilitated by Covidence, a systematic review management platform. A third reviewer will be engaged to resolve disagreements and facilitate consensus. A narrative summary of the major themes identified in the literature, numerical counts of relevant data including the COVID-19 positivity rates, and recommendations for different infection control approaches will be produced. Discussion: The synthesis of the research generated on COVID-19 prevalence and prevention in homeless shelters and hostels will assist in establishing best practices to prevent the spread of COVID-19 and other airborne diseases at these facilities in high-income countries while identifying next steps to expand the existing evidence base.
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Wu, Yingjie, Selim Gunay et Khalid Mosalam. Hybrid Simulations for the Seismic Evaluation of Resilient Highway Bridge Systems. Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, novembre 2020. http://dx.doi.org/10.55461/ytgv8834.
Texte intégralRésumé :
Bridges often serve as key links in local and national transportation networks. Bridge closures can result in severe costs, not only in the form of repair or replacement, but also in the form of economic losses related to medium- and long-term interruption of businesses and disruption to surrounding communities. In addition, continuous functionality of bridges is very important after any seismic event for emergency response and recovery purposes. Considering the importance of these structures, the associated structural design philosophy is shifting from collapse prevention to maintaining functionality in the aftermath of moderate to strong earthquakes, referred to as “resiliency” in earthquake engineering research. Moreover, the associated construction philosophy is being modernized with the utilization of accelerated bridge construction (ABC) techniques, which strive to reduce the impact of construction on traffic, society, economy and on-site safety. This report presents two bridge systems that target the aforementioned issues. A study that combined numerical and experimental research was undertaken to characterize the seismic performance of these bridge systems. The first part of the study focuses on the structural system-level response of highway bridges that incorporate a class of innovative connecting devices called the “V-connector,”, which can be used to connect two components in a structural system, e.g., the column and the bridge deck, or the column and its foundation. This device, designed by ACII, Inc., results in an isolation surface at the connection plane via a connector rod placed in a V-shaped tube that is embedded into the concrete. Energy dissipation is provided by friction between a special washer located around the V-shaped tube and a top plate. Because of the period elongation due to the isolation layer and the limited amount of force transferred by the relatively flexible connector rod, bridge columns are protected from experiencing damage, thus leading to improved seismic behavior. The V-connector system also facilitates the ABC by allowing on-site assembly of prefabricated structural parts including those of the V-connector. A single-column, two-span highway bridge located in Northern California was used for the proof-of-concept of the proposed V-connector protective system. The V-connector was designed to result in an elastic bridge response based on nonlinear dynamic analyses of the bridge model with the V-connector. Accordingly, a one-third scale V-connector was fabricated based on a set of selected design parameters. A quasi-static cyclic test was first conducted to characterize the force-displacement relationship of the V-connector, followed by a hybrid simulation (HS) test in the longitudinal direction of the bridge to verify the intended linear elastic response of the bridge system. In the HS test, all bridge components were analytically modeled except for the V-connector, which was simulated as the experimental substructure in a specially designed and constructed test setup. Linear elastic bridge response was confirmed according to the HS results. The response of the bridge with the V-connector was compared against that of the as-built bridge without the V-connector, which experienced significant column damage. These results justified the effectiveness of this innovative device. The second part of the study presents the HS test conducted on a one-third scale two-column bridge bent with self-centering columns (broadly defined as “resilient columns” in this study) to reduce (or ultimately eliminate) any residual drifts. The comparison of the HS test with a previously conducted shaking table test on an identical bridge bent is one of the highlights of this study. The concept of resiliency was incorporated in the design of the bridge bent columns characterized by a well-balanced combination of self-centering, rocking, and energy-dissipating mechanisms. This combination is expected to lead to minimum damage and low levels of residual drifts. The ABC is achieved by utilizing precast columns and end members (cap beam and foundation) through an innovative socket connection. In order to conduct the HS test, a new hybrid simulation system (HSS) was developed, utilizing commonly available software and hardware components in most structural laboratories including: a computational platform using Matlab/Simulink [MathWorks 2015], an interface hardware/software platform dSPACE [2017], and MTS controllers and data acquisition (DAQ) system for the utilized actuators and sensors. Proper operation of the HSS was verified using a trial run without the test specimen before the actual HS test. In the conducted HS test, the two-column bridge bent was simulated as the experimental substructure while modeling the horizontal and vertical inertia masses and corresponding mass proportional damping in the computer. The same ground motions from the shaking table test, consisting of one horizontal component and the vertical component, were applied as input excitations to the equations of motion in the HS. Good matching was obtained between the shaking table and the HS test results, demonstrating the appropriateness of the defined governing equations of motion and the employed damping model, in addition to the reliability of the developed HSS with minimum simulation errors. The small residual drifts and the minimum level of structural damage at large peak drift levels demonstrated the superior seismic response of the innovative design of the bridge bent with self-centering columns. The reliability of the developed HS approach motivated performing a follow-up HS study focusing on the transverse direction of the bridge, where the entire two-span bridge deck and its abutments represented the computational substructure, while the two-column bridge bent was the physical substructure. This investigation was effective in shedding light on the system-level performance of the entire bridge system that incorporated innovative bridge bent design beyond what can be achieved via shaking table tests, which are usually limited by large-scale bridge system testing capacities.
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NUMERICAL AND THEORETICAL STUDIES ON DOUBLE STEEL PLATE COMPOSITE WALLS UNDER COMPRESSION AT LOW TEMPERATURES. The Hong Kong Institute of Steel Construction, décembre 2021. http://dx.doi.org/10.18057/ijasc.2021.17.4.6.
Texte intégralRésumé :
Double steel plate composite walls (DSCWs) with several unique types of connectors have been implemented to protect offshore oil exploration platforms from concentric forces caused by ice in the Arctic region. This paper investigates the compressive perfor-mance of DSCWs with interlocked J-hooks and overlapped headed studs at low temperatures ranging from 20 ℃ to -80 ℃ with nonlinear finite element models (FEMs). The intricate geometric size of the concrete, multiple interactions of the concrete with the connectors, and material nonlinearities of the concrete have been thoroughly simulated. The reasonable consistency between the results of the monotonic tests and finite element analysis (FEA) on nine DSCWs with interlocked J-hooks and seven DSCWs with overlapped headed studs indicates that the FEMs can effectively predict the compressive performance of the DSCWs at low temper-atures. On the basis of the validated FEMs, the effects of the horizontal and vertical spacing of the connectors on the compressive performance of the DSCWs are studied. Finally, theoretical models of the load-displacement curves are developed to reveal the compressive response of DSCWs at low temperatures with different types of connectors, taking into account the restraining effect of steel plates on the inner concrete and the local buckling of steel plates. Compared with previous tests and FEA, the developed theoretical models have reasonable consistency for the load-displacement curves of DSCWs at low temperatures.