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Projects

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Mechanical cell deformation as a regulator for pharmaceutical response in bone cells (Swedish Research Council, 2020-2023) 

The current dogma suggests that loading induce an anabolic response while lack of loading induce bone degradation. However, clinical and experimental observations of prosthetic loosening demonstrate that mechanical overloading can induce bone loss. There is a gap in knowledge how mechanical signals regulate bone cells toward the catabolic stage, and how this will impact the pharmaceutical response. This might explain why there are no current pharmaceuticals to delay or stop prosthetic loosening. We aim to elucidate what physical factors induce bone cells to degrade bone instead of building up new bone, and to determine how mechanical loading affects bone cells to alter their response on pharmaceuticals. The main hypothesis is that increased shear stress rate per se, by its on cell deformation in bone, contributes significantly to bone loss leading to implant loosening. Several aspects of this approach are novel and innovative. First, the hypothesis is supportive of and draws data from recent thinking aboutosteoclastogenesis that involves enhanced mechanical loading instead of lack of loading. Second, using a combination of an experiments and computational models, we will provide a powerful tool to determine how bone cells respond on pharmaceuticals in presence of mechani loading.Understanding different mechanisms of implant failure this may open up for alternative strategies to inhibit or prevent osteolysis, thus delaying or eliminating revision surgery.

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A Fluid-Structure Interaction Model for Personalized Simulation and Data Analysis in Diagnosis and Treatment of Heart Valve Disease (Swedish Research Council, 2019-2022)

The purpose of this project is to develop a fluid-structure interaction model for patient-specific simulation of the blood flow in the left ventricle of the heart, including the valve structures, designed to be personalized by data acquired from a routine medical examination, such as 4D transthoracic echocardiography (ultrasound). The aim is that this model should enable in silico heart simulation technology to be advanced to a clinically relevant stage, to constitute a platform for evidence-based treatment by patient-specific simulation of disease progression and outcomes of clinical interventions. The PI of this proposal is an expert of computational mechanics, and is part of an interdisciplinary team of researchers encompassing expertise in cardiovascular medicine, medical imaging and flow visualization. The team has developed a first prototype of an envisioned clinical pathway, through which already more than 200 patients have been processed - to the best of our knowledge, more than any other personalized heart simulation model. This project addresses the basic science needed to make this prototype clinical pathway a reliable standard procedure.

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FEniCS-HPC

FEniCS-HPC is a set of software components based on the DOLFIN-HPC finite element library, optimized for massively parallel systems, including adaptive unstructured mesh algorithms, and the Unicorn solver for computational mechanics, with the features of fluid-structure interaction and moving mesh methods. The project is supported by SNIC (Swedish National Infrastructure for Computing) and PRACE (Partnership for Advanced Computing in Europe). 

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FEniCS

FEniCS is a widely used open source software project for the development of computational tools based on finite element technology for differential equations. Hoffman is one of the original co-founders of the FEniCS project in 2003. Specifically, as part of his thesis he co-developed the first version of DOLFIN in 2002

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Computational Technology Laboratory (CTL)

The Computational Technology Laboratory was initiated as the numerical analysis research group TACO at the KTH Royal Institute of Technology in Stockholm, Sweden. CTL then developd into a distributed research environment with two main nodes at KTH and BCAM (Basque Center of Applied Mathematics), supported by Bizkaia Talent.

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MSO4SC - Mathematical Modeling, Simulation and Optimization for Societal Challenges with Scientific Computing (EU H2020 e-infrastructure, 2016-2018)

Challenges of society show rising complexity and their solution process increasingly requires a holistic approach. The major objective of this project is to construct an e-infrastructure that provides, in a user-driven, integrative way, tailored access to the necessary services, resources and tools for an integrated MSO (mathematical Modelling, Simulation and Optimisation) application catalogue containing models, software, validation and benchmark and the MSOcloud: a user friendly cloud infrastructure for selected MSO applications and developing frameworks from the catalogue.

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Detailed CFD studies of vertical axis current turbines (Swedish Energy Agency, 2015-2018)

In this project, an advanced CFD model will be used to simulate several different turbine configurations and in detail analyze the force data. This will give extended knowledge about the blade forces, and it will also be used to create an uncertainty estimation of the errors of the simplified models, and to calibrate the simplified models for improved accuracy. 

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Automatiserade fluidmekaniska beräkningar för komplexa industriella tillämpningar (Vinnova, 2015-2018)

This goal of this project is to develop computational fluid dynamics technology in the form of an on-demand simulation service. In connection with this project the spinoff company Ingrid Cloud was founded. 

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ADAPTIVE (ERC PoC) Industrial implementation of adaptive computational methods for turbulent flow and fluid-structure interaction (European Ressearch Council, 2015-2016)

This European Research Council (ERC) Proof of Concept project aims to bring to the market the technology developed in the ERC Starting Grant project UNICON.

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Eunison - Extensive Unified-domain Simulation of the Human Voice (EU FET-Open, 2013-2016)

In this Future and Emerging Technologies (FET-Open) project, we seek to build a new voice simulator, based on physical first principles to an unprecedented degree. From given inputs, representing topology or muscle activations or phonemes, it will render the 3-D physics of the voice, including of course its acoustic output. This will give important insights into how the voice works, and how it fails. The goal is not a speech synthesis system, but rather a voice simulation engine, with many applications; given the right controls and enough computer time, it could be made to speak in any language, or sing in any style. The model will be operable on-line, as a reference and a platform for others to exploit in further studies. The long-term prospects include more natural-sounding speech synthesis, improved clinical procedures, greater public awareness of voice, better voice pedagogy and new forms of cultural expression.

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Adaptive Multiscale Modeling in Turbulent Flow and Fluid-structure Interaction with Applications in Engineering, Biology, Medicine and Geophysical Flow (Swedish Research Council, 2010-2016)

This is a Swedish Research Council (VR) Senior researcher fellowship with the research focus to develop robust, efficient and reliable adaptive finite element methods for multi scale modeling of turbulent fluid flow, with focus on real world applications from engineering, biology, medicine and geophysics. The goal of the adaptive algorithm is to automatically resolve sufficient small scale structures of the model to approximate certain output of interest to a given accuracy, while minimizing the computational cost. Particular emphasis is put on geometry representation and boundary conditions, fluid-structure interaction, and efficient algorithms for parallel computing.

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High Performance Adaptive Methods for Computer Simulaton of Turbulent Stratified Flow in Complex Domains with Applications to Ocean and Atmosphere Modeling (Swedish Research Council, 2012-2014)

The purpose of this Swedish Research Council (VR) project is to develop efficient and reliable adaptive computational methods for turbulent stratified flow in complex domains, for high performance computer architectures, with applications to ocean and atmosphere modeling, to contribute to the understanding and simulation capabilities of the research community.

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UNICON (ERC StG) New Adaptive Computational Methods for Fluid-Structure Interaction Using a Unified Continuum Formulation with Applications in Biology, Medicine and Industry (European Research Council, 2008-2013)

In this European Research Council (ERC) Starting Grant project we develop Unified Continuum Fluid-structure Interaction (UC-FSI) which is based on a formulation of fluid-structure interaction as a multiphase flow problem over one single continuum, which leads to a robust method suitable for analysis. We apply the method to the development of models of e.g. the human heart, and vocal folds.

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New Technology for Advanced Simulation of Turbulent Flow (Swedish Foundation for Strategic Research, 2008-2013)

The main goal of this project is to develop general, reliable and efficient computational methods for turbulent flow problems of major scientific and industrial importance, where we extend our results for turbulent incompressible flow to compressible flow and fluid-structure interaction. One key focus is the development of high performance computing technologies to make the implementation of the methods efficient. Funded by the Advancement of Research Leaders Grant of the Swedish Foundation for Strategic Research (SSF FFL).  

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Computational Biomedicine and a Virtual Human Heart (Wenner-Gren Foundations, 2011-2012)

Based on ultra sound images we build a finite element model of the blood flow in the left ventricle of the human heart. This project funded a 6 months research visit to Auckland Bioengineering Institute to develop the heart model, and to establish new contacts in the area of biomedical modeling. 

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Aero-acoustic Virtual Design of Exhaust Systems (Vinnova, 2007-2011) 

Development of a computational model for predicting aero-acoustic properties of exhaust systems, including turbulent air flow and fluid-structure interaction. This project was done in collaboration with the Marcus Wallenberg Laboratory for sound and vibrations at KTH and Swenox, a leading manufacturer of exhaust systems for the European car industry. Funded by the Swedish Governmental Agency for Innovation Systems (Vinnova) (2007) and the Swedish Energy Agency (2009-2011).

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SimVisInt (2009-2011)

SimVisInt was a strategic platform at the School of Computer Science and Communication at KTH, which brought together research in simulation, visualization and interactivity. A particular focus was on Computational Human Modeling and Visualization, with projects on the human heart, human motion, and virtual prototyping of human hand prostheses. 

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Adaptive Computation of Turbulent Flow (Swedish Foundation for Strategic Research, 2006-2009)

This project concerned the development of adaptive finite element methods for turbulence simulation based on quantitative a posteriori error control, where LES filtering and subgrid modeling is avoided by direct computation of weak solutions to the Navier-Stokes equations. Turbulent flow separation was investigated and new efficient models for turbulent boundary layers were developed. Funded by the Ingvar Carlsson Award of the Swedish Foundation for Strategic Research (SSF ICA). 

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Adaptive Finite Element Methods for Turbulent Flow (Swedish Research Council, 2006-2008)

In this Swedish Research Council (VR) project we developed adaptive finite element methods based on a posteriori error estimation, with a focus on compressible turbulent flow. 

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