199 results on '"A. R. Brodtkorb"'
Search Results
2. Simulating the Euler equations on multiple GPUs using Python
- Author
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André R. Brodtkorb and Martin L. Sætra
- Subjects
GPU computing ,CFD ,conservation laws ,finite-volume methods ,Python ,CUDA ,Physics ,QC1-999 - Abstract
GPUs have become a household name in High Performance Computing (HPC) systems over the last 15 years. However, programming GPUs is still largely a manual and arduous task, which requires expert knowledge of the physics, mathematics, and computer science involved. Even though there have been large advances in automatic parallelization and GPU execution of serial code, it is still difficult to fully utilize the GPU hardware with such approaches. Many core numeric GPU codes are therefore still mostly written using low level C/C++ or Fortran for the host code. Several studies have shown that using higher level languages, such as Python, can make software development faster and with fewer bugs. We have developed a simulator based on PyCUDA and mpi4py in Python for solving the Euler equations on Cartesian grids. Our framework utilizes the GPU, and can automatically run on clusters using MPI as well as on shared-memory systems. Our framework allows the programmer to implement low-level details in CUDA C/C++, which is important to achieve peak performance, whilst still benefiting from the productivity of Python. We show that our framework achieves good weak and strong scaling. Our weak scaling achieves more than 94% efficiency on a shared-memory GPU system and more than 90% efficiency on a distributed-memory GPU system, and our strong scaling is close to perfect on both shared-memory and distributed-memory GPU systems.
- Published
- 2022
- Full Text
- View/download PDF
3. Coastal ocean forecasting on the GPU using a two-dimensional finite-volume scheme
- Author
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André R. Brodtkorb and HÅvard Heitlo Holm
- Subjects
shallow-water equations ,oceanography ,gpu computing ,realistic use cases ,high-resolution finite-volume methods ,Oceanography ,GC1-1581 ,Meteorology. Climatology ,QC851-999 - Abstract
In this work, we take a modern high-resolution finite-volume scheme for solving the rotational shallow-water equations and extend it with features required to run real-world ocean simulations. Our contributions include a spatially varying north vector and Coriolis term required for large scale domains, moving wet-dry fronts, a static land mask, bottom shear stress, wind forcing, boundary conditions for nesting in a global model, and an efficient model reformulation that makes it well-suited for massively parallel implementations. Our model order is verified using a grid convergence test, and we show numerical experiments using three different sections along the coast of Norway based on data originating from operational forecasts run at the Norwegian Meteorological Institute. Our simulation framework shows perfect weak scaling on a modern P100 GPU, and is capable of providing tidal wave forecasts that are very close to the operational model at a fraction of the cost. All source code and data used in this work are publicly available under open licenses.
- Published
- 2021
- Full Text
- View/download PDF
4. Performance and Energy Efficiency of CUDA and OpenCL for GPU Computing Using Python.
- Author
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Håvard H. Holm, André R. Brodtkorb, and Martin Lilleeng Sætra
- Published
- 2019
- Full Text
- View/download PDF
5. Estimating volcanic ash emissions using retrieved satellite ash columns and inverse ash transport modelling.
- Author
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André R. Brodtkorb, Anna Benedictow, Heiko Klein, Arve Kylling, Agnes Nyiri, Alvaro Valdebenito, and Espen Sollum
- Published
- 2020
6. Simplified Ocean Models on the GPU.
- Author
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André R Brodtkorb
- Published
- 2018
7. Real-World Oceanographic Simulations on the GPU using a Two-Dimensional Finite-Volume Scheme.
- Author
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André R. Brodtkorb and Håvard Heitlo Holm
- Published
- 2019
8. GPU Computing with Python: Performance, Energy Efficiency and Usability.
- Author
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Håvard H. Holm, André R. Brodtkorb, and Martin Lilleeng Sætra
- Published
- 2019
9. Estimating volcanic ash emissions using retrieved satellite ash columns and inverse ash transport modelling using VolcanicAshInversion v1.2.1, within the operational eEMEP volcanic plume forecasting system (version rv4_17)
- Author
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André R. Brodtkorb, Anna Benedictow, Heiko Klein, Arve Kylling, Agnes Nyiri, Alvaro Valdebenito, Espen Sollum, and Nina Kristiansen
- Abstract
Accurate modelling of ash clouds from volcanic eruptions requires knowledge about the eruption source parameters including eruption onset, duration, mass eruption rates, particle size distribution, and vertical emission profiles. However, most of these parameters are unknown and must be estimated somehow. Some are estimated based on observed correlations and known volcano parameters. However, a more accurate estimate is often needed to bring the model into closer agreement to observations. This paper describes the inversion procedure implemented at the Norwegian Meteorological Institute for estimating ash emission rates from retrieved satellite ash column amounts and a priori knowledge. The overall procedure consists of five stages: (1) generate a priori emission estimates; (2) run forward simulations with a set of unit emission profiles; (3) collocate/match observations with emission simulations; (4) build system of linear equations; and (5) solve overdetermined system. We go through the mathematical foundations for the inversion procedure, performance for synthetic cases, and performance for real-world cases. The novelties of this paper includes a memory efficient formulation of the inversion problem, a detailed description and illustrations of the mathematical formulations, evaluation of the inversion method using synthetic known truth data as well as real data, and inclusion of observations of ash cloud-top height. The source code used in this work is freely available under an open source license, and is possible to use for other similar applications.
- Published
- 2023
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10. VISUALIZATION OF MARINE SAND DUNE DISPLACEMENTS UTILIZING MODERN GPU TECHNIQUES
- Author
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T. Gierlinger, A. R. Brodtkorb, A. Stumpf, M. Weiler, and F. Michel
- Subjects
Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Applied optics. Photonics ,TA1501-1820 - Abstract
Quantifying and visualizing deformation and material fluxes is an indispensable tool for many geoscientific applications at different scales comprising for example global convective models (Burstedde et al., 2013), co-seismic slip (Leprince et al., 2007) or local slope deformation (Stumpf et al., 2014b). Within the European project IQmulus (http://www.iqmulus.eu) a special focus is laid on the efficient detection and visualization of submarine sand dune displacements. In this paper we present our approaches on the visualization of the calculated displacements utilizing modern GPU techniques to enable the user to interactively analyze intermediate and final results within the whole workflow.
- Published
- 2015
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11. GPU Computing with Python: Performance, Energy Efficiency and Usability.
- Author
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Håvard H. Holm, André R. Brodtkorb, and Martin Lilleeng Sætra
- Published
- 2020
- Full Text
- View/download PDF
12. GPU computing in discrete optimization. Part I: Introduction to the GPU.
- Author
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André R. Brodtkorb, Trond R. Hagen, Christian Schulz 0002, and Geir Hasle
- Published
- 2013
- Full Text
- View/download PDF
13. GPU computing in discrete optimization. Part II: Survey focused on routing problems.
- Author
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Christian Schulz 0002, Geir Hasle, André R. Brodtkorb, and Trond R. Hagen
- Published
- 2013
- Full Text
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14. Performance and Energy Efficiency of CUDA and OpenCL for GPU Computing Using Python
- Author
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Håvard Heitlo Holm, Martin L. Sætra, and André R. Brodtkorb
- Subjects
CUDA ,Computer science ,Parallel computing ,ComputerSystemsOrganization_PROCESSORARCHITECTURES ,Software_PROGRAMMINGTECHNIQUES ,General-purpose computing on graphics processing units ,Python (programming language) ,computer ,ComputingMethodologies_COMPUTERGRAPHICS ,Efficient energy use ,computer.programming_language - Abstract
In this work, we examine the performance and energy efficiency when using Python for developing HPC codes running on the GPU. We investigate the portability of performance and energy efficiency between CUDA and OpenCL; between GPU generations; and between low-end, mid-range and high-end GPUs. Our findings show that for some combinations of GPU and GPU code, there is a significant speedup for CUDA over OpenCL, but that this does not hold in general. Our experiments show that performance in general varies more between different GPUs, than between using CUDA and OpenCL. Finally, we show that tuning for performance is a good way of tuning for energy efficiency.
- Published
- 2020
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15. Data Assimilation for Ocean Drift Trajectories Using Massive Ensembles and GPUs
- Author
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Håvard Heitlo Holm, André R. Brodtkorb, and Martin L. Sætra
- Subjects
Work (thermodynamics) ,Computer science ,Finite volume methods ,Shallow water simulations ,Nonlinear system ,Data assimilation ,Resampling ,Particle filters ,Particle filter ,Algorithm ,Trajectory (fluid mechanics) ,Scaling ,Physics::Atmospheric and Oceanic Physics - Abstract
In this work, we perform fully nonlinear data assimilation of ocean drift trajectories using multiple GPUs. We use an ensemble of up to 10000 members and the sequential importance resampling algorithm to assimilate observations of drift trajectories into the underlying shallow-water simulation model. Our results show an improved drift trajectory forecast using data assimilation for a complex and realistic simulation scenario, and the implementation exhibits good weak and strong scaling. This work is supported by the Research Council of Norway (RCN) through grant number 250935 (GPU Ocean). The computations in this paper were performed on equipment provided by the Experimental Infrastructure for Exploration of Exascale Computing (eX3 ), which is financially supported by the RCN under contract 270053. The source code for the methods and experiments described in this paper is available under an GNU free and open source license released under https://doi.org/10.5281/zenodo.3591850.
- Published
- 2020
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16. Comparison Between Algebraic Multigrid and Multilevel Multiscale Methods for Reservoir Simulation
- Author
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André R. Brodtkorb, K. Bao, Halvor Møll Nilsen, Olav Møyner, Arthur Moncorgé, and Knut-Andreas Lie
- Subjects
CUDA ,Multigrid method ,Rate of convergence ,Preconditioner ,Computer science ,Domain decomposition methods ,Basis function ,Parallel computing ,Solver ,Smoothing - Abstract
Summary Multiscale methods for solving strongly heterogenous systems in reservoirs have a long history from the early ideas used on incompressible flow to the newly released version in commercial simulation. Much effort has been put into making the MsFV method work for fully unstructured multiphase problems. The MsRSB version is a newly developed version, which tackles most of the "real" world problems. It is to our knowledge, the only multiscale method that has been released in a commercial simulator. You can alternatively see the method as a variant of smoothed aggregation or as an iterative approach to AMG with energy minimizing basis functions. This will be discussed in detail. So far, most work on comparing MsRSB with AMG methods has been on qualitative performance measures like iteration number rather than on pure runtime on fair code implementation. We discuss the theoretical performance and show the practical performance for our implementation. Here, we compare performance of pure AMG, standard two-level MsRSB with pure AMG as coarse solver, as well as a new truly multilevel MsRSB scheme. Our implementation uses the DUNE-ISTL framework. To limit the scope of the discussion we restrict our assessment to AMG with aggregation and smoothed aggregation and the MsRSB method. These three methods are closely related and are primarily distinguished in a preconditioner setting by the coarsening factors used, and the degree of smoothing applied to the basis. We also compare with other state-of-the-art AMG implementations, but do not investigate combinations of them with the MSRB method. For the MsRSB method, we also discuss practical considerations in different parallelization regimes including domain decomposition using MPI, shared memory using OpenMP, and GPU acceleration with CUDA. All comparisons will focus on the setting in which many similar systems should be solved, e.g. during a large-scale, multiphase flow simulation. That is, our emphasis is on the performance of updating a preconditioner and on the apply time for the preconditioner relative to the convergence rate. Performance of the solvers will be tested for pure parabolic/elliptic problems that either arise as part of a sequential splitting procedure or as a pseudo-elliptic preconditioner/solver as a part of a CPR preconditioner for a multiphase system, for which block ILU0 is used as the outer smoother.
- Published
- 2020
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17. Coastal ocean forecasting on the GPU using a two-dimensional finite-volume scheme
- Author
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HÅvard Heitlo Holm and André R. Brodtkorb
- Subjects
Scheme (programming language) ,Atmospheric Science ,Finite volume method ,High-resolution finite-volume methods ,Computer science ,Realistic use cases ,Ocean forecasting ,realistic use cases ,GC1-1581 ,GPU computing ,Oceanography ,high-resolution finite-volume methods ,shallow-water equations ,Computational science ,Work (electrical) ,Meteorology. Climatology ,QC851-999 ,General-purpose computing on graphics processing units ,Shallow-water equations ,Shallow water equations ,computer ,Physics::Atmospheric and Oceanic Physics ,gpu computing ,ComputingMethodologies_COMPUTERGRAPHICS ,computer.programming_language - Abstract
In this work, we take a modern high-resolution finite-volume scheme for solving the rotational shallow-water equations and extend it with features required to run real-world ocean simulations. Our contributions include a spatially varying north vector and Coriolis term required for large scale domains, moving wet-dry fronts, a static land mask, bottom shear stress, wind forcing, boundary conditions for nesting in a global model, and an efficient model reformulation that makes it well-suited for massively parallel implementations. Our model order is verified using a grid convergence test, and we show numerical experiments using three different sections along the coast of Norway based on data originating from operational forecasts run at the Norwegian Meteorological Institute. Our simulation framework shows perfect weak scaling on a modern P100 GPU, and is capable of providing tidal wave forecasts that are very close to the operational model at a fraction of the cost. All source code and data used in this work are publicly available under open licenses. This research has mainly been funded by the Research Council of Norway under grant number 250935 (GPU Ocean), and partly by grant number 310515 (Havvarsel). The GPU Ocean project has received support in form of compute time on UNINETT Sigma2 - the National Infrastructure for High Performance Computing and Data Storage in Norway under project number nn9550k.
- Published
- 2021
- Full Text
- View/download PDF
18. GPU Computing with Python: Performance, Energy Efficiency and Usability
- Author
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Håvard Heitlo Holm, Martin L. Sætra, and André R. Brodtkorb
- Subjects
FOS: Computer and information sciences ,General Computer Science ,Computer science ,CUDA ,010103 numerical & computational mathematics ,02 engineering and technology ,Parallel computing ,Graphic processing units ,Software_PROGRAMMINGTECHNIQUES ,01 natural sciences ,lcsh:QA75.5-76.95 ,Theoretical Computer Science ,Computing unified device architecture ,Shallow water simulations ,Software portability ,020204 information systems ,0202 electrical engineering, electronic engineering, information engineering ,Power efficiency ,0101 mathematics ,computer.programming_language ,OpenCL ,business.industry ,Applied Mathematics ,65Y05, 68U20 ,high-performance computing ,Usability ,Python (programming language) ,shallow-water simulation ,GPU computing ,ComputerSystemsOrganization_PROCESSORARCHITECTURES ,Power efficiency ,Computer Science::Performance ,Computer Science::Graphics ,Computer Science - Distributed, Parallel, and Cluster Computing ,Modeling and Simulation ,Shallow-water simulation ,Computer Science::Mathematical Software ,Open compute languages ,lcsh:Electronic computers. Computer science ,High performance computing ,Distributed, Parallel, and Cluster Computing (cs.DC) ,General-purpose computing on graphics processing units ,business ,power efficiency ,computer ,Efficient energy use - Abstract
In this work, we examine the performance, energy efficiency, and usability when using Python for developing high-performance computing codes running on the graphics processing unit (GPU). We investigate the portability of performance and energy efficiency between Compute Unified Device Architecture (CUDA) and Open Compute Language (OpenCL), between GPU generations, and between low-end, mid-range, and high-end GPUs. Our findings showed that the impact of using Python is negligible for our applications, and furthermore, CUDA and OpenCL applications tuned to an equivalent level can in many cases obtain the same computational performance. Our experiments showed that performance in general varies more between different GPUs than between using CUDA and OpenCL. We also show that tuning for performance is a good way of tuning for energy efficiency, but that specific tuning is needed to obtain optimal energy efficiency.
- Published
- 2019
- Full Text
- View/download PDF
19. VISUALIZATION OF MARINE SAND DUNE DISPLACEMENTS UTILIZING MODERN GPU TECHNIQUES
- Author
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M. Weiler, A. Stumpf, André R. Brodtkorb, F. Michel, and T. Gierlinger
- Subjects
lcsh:Applied optics. Photonics ,lcsh:T ,modern GPU techniques ,Submarine ,lcsh:TA1501-1820 ,geological displacements ,Slip (materials science) ,lcsh:Technology ,Sand dune stabilization ,Visualization ,Geography ,Workflow ,lcsh:TA1-2040 ,Computer graphics (images) ,lcsh:Engineering (General). Civil engineering (General) ,Interactive visualization ,interactive visualization - Abstract
Quantifying and visualizing deformation and material fluxes is an indispensable tool for many geoscientific applications at different scales comprising for example global convective models (Burstedde et al., 2013), co-seismic slip (Leprince et al., 2007) or local slope deformation (Stumpf et al., 2014b). Within the European project IQmulus (http://www.iqmulus.eu) a special focus is laid on the efficient detection and visualization of submarine sand dune displacements. In this paper we present our approaches on the visualization of the calculated displacements utilizing modern GPU techniques to enable the user to interactively analyze intermediate and final results within the whole workflow.
- Published
- 2015
20. Efficient GPU-Implementation of Adaptive Mesh Refinement for the Shallow-Water Equations
- Author
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Knut-Andreas Lie, Martin L. Sætra, and André R. Brodtkorb
- Subjects
Numerical Analysis ,Adaptive mesh refinement ,Computer science ,Applied Mathematics ,General Engineering ,Domain decomposition methods ,Parallel computing ,Grid ,Stencil ,Theoretical Computer Science ,Computational Mathematics ,CUDA ,Computational Theory and Mathematics ,General-purpose computing on graphics processing units ,Shallow water equations ,Software ,ComputingMethodologies_COMPUTERGRAPHICS ,Block (data storage) - Abstract
The shallow-water equations model hydrostatic flow below a free surface for cases in which the ratio between the vertical and horizontal length scales is small and are used to describe waves in lakes, rivers, oceans, and the atmosphere. The equations admit discontinuous solutions, and numerical solutions are typically computed using high-resolution schemes. For many practical problems, there is a need to increase the grid resolution locally to capture complicated structures or steep gradients in the solution. An efficient method to this end is adaptive mesh refinement (AMR), which recursively refines the grid in parts of the domain and adaptively updates the refinement as the simulation progresses. Several authors have demonstrated that the explicit stencil computations of high-resolution schemes map particularly well to many-core architectures seen in hardware accelerators such as graphics processing units (GPUs). Herein, we present the first full GPU-implementation of a block-based AMR method for the second-order Kurganov---Petrova central scheme. We discuss implementation details, potential pitfalls, and key insights, and present a series of performance and accuracy tests. Although it is only presented for a particular case herein, we believe our approach to GPU-implementation of AMR is transferable to other hyperbolic conservation laws, numerical schemes, and architectures similar to the GPU.
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- 2014
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21. Graphics processing unit (GPU) programming strategies and trends in GPU computing
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Martin L. Sætra, Trond Runar Hagen, and André R. Brodtkorb
- Subjects
Profiling (computer programming) ,Multimedia ,Computer Networks and Communications ,Computer science ,Process (engineering) ,media_common.quotation_subject ,Graphics processing unit ,Symmetric multiprocessor system ,Parallel computing ,computer.software_genre ,Theoretical Computer Science ,Stream processing ,Debugging ,Artificial Intelligence ,Hardware and Architecture ,Graphics ,General-purpose computing on graphics processing units ,Metaheuristic ,computer ,Software ,ComputingMethodologies_COMPUTERGRAPHICS ,media_common - Abstract
Over the last decade, there has been a growing interest in the use of graphics processing units (GPUs) for non-graphics applications. From early academic proof-of-concept papers around the year 2000, the use of GPUs has now matured to a point where there are countless industrial applications. Together with the expanding use of GPUs, we have also seen a tremendous development in the programming languages and tools, and getting started programming GPUs has never been easier. However, whilst getting started with GPU programming can be simple, being able to fully utilize GPU hardware is an art that can take months or years to master. The aim of this article is to simplify this process, by giving an overview of current GPU programming strategies, profile-driven development, and an outlook to future trends.
- Published
- 2013
- Full Text
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22. Efficient shallow water simulations on GPUs: Implementation, visualization, verification, and validation
- Author
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Martin L. Sætra, Mustafa S. Altinakar, and André R. Brodtkorb
- Subjects
CUDA ,General Computer Science ,Real-time simulation ,Computer science ,General Engineering ,Symmetric multiprocessor system ,Graphics ,Shallow water equations ,Single-precision floating-point format ,Computational science ,Visualization ,Verification and validation - Abstract
In this paper, we present an efficient implementation of a state-of-the-art high-resolution explicit scheme for the shallow water equations on graphics processing units. The selected scheme is well-balanced, supports dry states, and is particularly suitable for implementation on graphics processing units. We verify and validate our implementation, and show that use of efficient single precision hardware is sufficiently accurate for real-world simulations. Our framework further supports real-time visualization with both photorealistic and non-photorealistic display of the physical quantities. We present performance results showing that we can accurately simulate the first 4000 s of the Malpasset dam break case in 27 s using over 480,000 cells ( dx = dy = 15 m), in which our simulator runs at an average of 530 megacells per second.
- Published
- 2012
- Full Text
- View/download PDF
23. Simulation and visualization of the Saint-Venant system using GPUs
- Author
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Trond Runar Hagen, Knut-Andreas Lie, Jostein R. Natvig, and André R. Brodtkorb
- Subjects
State variable ,Computer science ,General Engineering ,Bilinear interpolation ,Grid ,Theoretical Computer Science ,Visualization ,Rendering (computer graphics) ,Computational science ,CUDA ,Computational Theory and Mathematics ,Modelling and Simulation ,Modeling and Simulation ,Scalability ,Computer Vision and Pattern Recognition ,High-resolution scheme ,Algorithm ,Engineering(all) ,Software ,ComputingMethodologies_COMPUTERGRAPHICS - Abstract
We consider three high-resolution schemes for computing shallow-water waves as described by the Saint-Venant system and discuss how to develop highly efficient implementations using graphical processing units (GPUs). The schemes are well-balanced for lake-at-rest problems, handle dry states, and support linear friction models. The first two schemes handle dry states by switching variables in the reconstruction step, so that bilinear reconstructions are computed using physical variables for small water depths and conserved variables elsewhere. In the third scheme, reconstructed slopes are modified in cells containing dry zones to ensure non-negative values at integration points. We discuss how single and double-precision arithmetics affect accuracy and efficiency, scalability and resource utilization for our implementations, and demonstrate that all three schemes map very well to current GPU hardware. We have also implemented direct and close-to-photo-realistic visualization of simulation results on the GPU, giving visual simulations with interactive speeds for reasonably-sized grids.
- Published
- 2010
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24. State-of-the-art in Heterogeneous Computing
- Author
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Jon M. Hjelmervik, Christopher Dyken, Trond Runar Hagen, André R. Brodtkorb, and Olaf O. Storaasli
- Subjects
Workstation ,Cost efficiency ,business.industry ,Computer science ,Symmetric multiprocessor system ,Computer Science Applications ,law.invention ,QA76.75-76.765 ,Software ,Computer architecture ,law ,Parallelism (grammar) ,Computer software ,State (computer science) ,Graphics ,Field-programmable gate array ,business - Abstract
Node level heterogeneous architectures have become attractive during the last decade for several reasons: compared to traditional symmetric CPUs, they offer high peak performance and are energy and/or cost efficient. With the increase of fine-grained parallelism in high-performance computing, as well as the introduction of parallelism in workstations, there is an acute need for a good overview and understanding of these architectures. We give an overview of the state-of-the-art in heterogeneous computing, focusing on three commonly found architectures: the Cell Broadband Engine Architecture, graphics processing units (GPUs), and field programmable gate arrays (FPGAs). We present a review of hardware, available software tools, and an overview of state-of-the-art techniques and algorithms. Furthermore, we present a qualitative and quantitative comparison of the architectures, and give our view on the future of heterogeneous computing.
- Published
- 2010
- Full Text
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25. Real-time online camera synchronization for volume carving on GPU
- Author
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Anna Kim, Torkel Andreas Haufmann, André R. Brodtkorb, and A. Berge
- Subjects
Carving ,Computer science ,business.industry ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Volume (computing) ,Iterative reconstruction ,Synchronization ,Set (abstract data type) ,Computer graphics ,Computer graphics (images) ,Calibration ,Computer vision ,Artificial intelligence ,State (computer science) ,business - Abstract
Volume carving is a well-known technique for reconstructing a 3D scene from a set of 2D images, using features detected in individual cameras, and camera parameters. Spatial calibration of the cameras is well understood, but the resulting carved volume is very sensitive to temporal offsets between the cameras. Automatic synchronization between the cameras is therefore desirable. In this paper, we present a highly efficient implementation of volume carving and synchronization on a heterogeneous system fitted with commodity GPUs using an improved version of the algorithm in [1]. An online, real-time synchronization system is described and evaluated on surveillance video of an indoor scene. Improvements to the state of the art CPU-based algorithms are described.
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- 2013
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26. GPU Computing in Discrete Optimization Part I: Introduction to the GPU
- Author
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Trond Runar Hagen, André R. Brodtkorb, Geir Hasle, and Christian Schulz
- Subjects
Exploit ,Computer science ,Transportation ,Symmetric multiprocessor system ,Parallel computing ,Management Science and Operations Research ,Supercomputer ,Stream processing ,CUDA ,Computer architecture ,Modeling and Simulation ,Discrete optimization ,Vehicle routing problem ,General-purpose computing on graphics processing units - Abstract
In many cases there is still a large gap between the performance of current optimization technology and the requirements of real world applications. As in the past, performance will improve through a combination of more powerful solution methods and a general performance increase of computers. These factors are not independent. Due to physical limits, hardware development no longer results in higher speed for sequential algorithms, but rather in increased parallelism. Modern commodity PCs include a multi-core CPU and at least one GPU, providing a low cost, easily accessible heterogeneous environment for high performance computing. New solution methods that combine task parallelization and stream processing are needed to fully exploit modern computer architectures and profit from future hardware developments. This paper is the first part of a series of two, where the goal of this first part is to give a tutorial style introduction to modern PC architectures and GPU programming. We start with a short historical account of modern mainstream computer architectures, and a brief description of parallel computing. This is followed by the evolution of modern GPUs, before a GPU programming example is given. Strategies and guidelines for program development are also discussed. Part II gives a broad survey of the existing literature on parallel computing targeted at modern PCs in discrete optimization, with special focus on papers on routing problems. We conclude with lessons learnt, directions for future research, and prospects.
- Published
- 2013
27. Shallow Water Simulations on Multiple GPUs
- Author
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Martin L. Sætra and André R. Brodtkorb
- Subjects
Waves and shallow water ,CUDA ,Finite volume method ,Computer science ,Computation ,Domain decomposition methods ,Parallel computing ,Scaling ,Shallow water equations ,Computational science ,Flooding (computer networking) - Abstract
We present a state-of-the-art shallow water simulator running on multiple GPUs. Our implementation is based on an explicit high-resolution finite volume scheme suitable for modeling dam breaks and flooding. We use row domain decomposition to enable multi-GPU computations, and perform traditional CUDA block decomposition within each GPU for further parallelism. Our implementation shows near perfect weak and strong scaling, and enables simulation of domains consisting of up-to 235 million cells at a rate of over 1.2 gigacells per second using four Fermi-generation GPUs. The code is thoroughly benchmarked using three different systems, both high-performance and commodity-level systems.
- Published
- 2012
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28. A Comparison of Three Commodity-Level Parallel Architectures: Multi-core CPU, Cell BE and GPU
- Author
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Trond Runar Hagen and André R. Brodtkorb
- Subjects
Multi-core processor ,Motion JPEG ,Shared memory ,Computer science ,Discrete cosine transform ,Inpainting ,Parallel computing ,Mandelbrot set ,Graphics ,Direct memory access - Abstract
We explore three commodity parallel architectures: multi-core CPUs, the Cell BE processor, and graphics processing units. We have implemented four algorithms on these three architectures: solving the heat equation, inpainting using the heat equation, computing the Mandelbrot set, and MJPEG movie compression. We use these four algorithms to exemplify the benefits and drawbacks of each parallel architecture.
- Published
- 2010
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29. The Graphics Processor as a Mathematical Coprocessor in MATLAB
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André R. Brodtkorb
- Subjects
Numerical linear algebra ,Coprocessor ,Computer science ,Interface (computing) ,MathematicsofComputing_NUMERICALANALYSIS ,Graphics processing unit ,Parallel computing ,computer.software_genre ,Single-precision floating-point format ,Computational science ,Central processing unit ,Graphics ,MATLAB ,Computer Science::Operating Systems ,computer ,computer.programming_language - Abstract
We present an interface to the graphics processing unit (GPU) from MATLAB, and four algorithms from numerical linear algebra available through this interface; matrix-matrix multiplication, Gauss-Jordan elimination, PLU factorization, and tridiagonal Gaussian elimination. In addition to being a high level abstraction to the GPU, the interface offers background processing, enabling computations to be executed on the CPU simultaneously. The algorithms are shown to be up-to 31 times faster than highly optimized CPU code. The algorithms have only been tested on single precision hardware, but will easily run on new double precision hardware.
- Published
- 2008
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30. Erratum to 'Efficient shallow water simulations on GPUs: Implementation, visualization, verification and validation' [Comp Fluids 55 (2012) 1–12]
- Author
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André R. Brodtkorb, Mustafa S. Altinakar, and Martin L. Sætra
- Subjects
Waves and shallow water ,General Computer Science ,Computer science ,General Engineering ,Visualization ,Computational science ,Verification and validation - Published
- 2012
- Full Text
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31. At være gammel på plejehjem.
- Author
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Hammershøj, Maiken, Lovring, Iben, Sylvestersen, Janna Bohn, and Henriksen, Jette
- Abstract
Background: Studies indicate that nursing homes are special places that require getting used to feel comfortable. Changing staff might challenge the residents' individual needs and experience of recognition. The purpose of this study is to gain insight into the residents' perception of what they experience as significant in everyday life. Method: Qualitative, individual, semi-structured interviews were carried out with eight residents in nursing homes. The analysis is inspired by Malterud's systematic text condensation. Two main themes emerged: 1. Individual care: The importance of the staff in creating well-being and safety in the nursing home and 2: The importance of being together with like-minded residents and individually adapted activities. Conclusion: The findings indicate that it is of great importance that the staff show an interest in the residents as well as their interaction with the other residents. Activities can facilitate social contact, while the activities must meet the individual resident's unique preferences. [ABSTRACT FROM AUTHOR]
- Published
- 2025
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32. Effects of Alcohol and Its Relationship with Deranged Liver Function Tests and Withdrawal Symptoms.
- Author
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Thangarajan, Remitha Joseph, Sureshkumar, Kailash, Kailash, Shabeeba Z., and Manogaran, Aravindh
- Subjects
ALCOHOL withdrawal syndrome ,ALCOHOLISM ,MEDICAL personnel ,NICOTINE addiction ,DRUG withdrawal symptoms - Abstract
Alcohol consumption is an important risk factor for illness, disability, and mortality. Alcohol withdrawal symptoms have a significant health concern for individuals with alcohol dependence. This study aims to investigate the prevalence of withdrawal symptoms and liver function test abnormalities in this population and also to identify the factors associated with the severity of withdrawal symptoms. This cross-sectional study was conducted at a tertiary care facility involving 100 patients seeking treatment for alcohol dependence. Data collection included structured interviews and assessments using standardized scales and biochemical tests. Descriptive statistics, t-tests, and chi-square tests were employed to analyse the data. Individuals exhibiting mild/moderate alcohol withdrawal symptoms in this study displayed several distinctive features. They were more likely to have attained at least a high school education, their average alcohol consumption was notably lower, Importantly, their blood parameters, including RBC count, platelet count, total bilirubin levels, and liver enzyme levels (AST and ALT), generally exhibited fewer deviations from normal ranges. Family history of alcohol dependence and nicotine dependence was common among the participants. This research highlights the need for a holistic approach to address alcohol dependence, taking into consideration sociodemographic factors, clinical markers, and the diverse nature of this condition. The findings provide important insights for healthcare professionals to identify individuals at higher risk and guide treatment decisions. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
33. Efficient numerical simulation on dielectric barrier discharges at atmospheric pressure integrated by deep neural network.
- Author
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Zhang, Yuan-Tao, Gao, Shu-Han, and Zhu, Yun-Yu
- Subjects
ATMOSPHERIC pressure ,GLOW discharges ,COMPUTER simulation ,DIELECTRICS ,ELECTRIC fields - Abstract
Numerical simulation is an essential way to investigate the discharge behaviors of atmospheric low-temperature plasmas (LTPs). In this study, a deep neural network (DNN) with multiple hidden layers is constructed to surrogate the fluid model to investigate the discharge characteristics of atmospheric helium dielectric barrier discharges (DBDs) with very high computational efficiency, working as an example to show the ability and validity of DNN to explore LTPs. The DNN is trained by the well-formed training datasets obtained from a verified fluid model, and a designed loss function coupled in the DNN program is continuously optimized to achieve a better prediction performance. The predicted data show that the essential discharge characteristics of atmospheric DBDs such as the discharge current waveforms, spatial profiles of charged particles, and electric field can be yielded by the well-trained DNN program with great accuracy only in several seconds, and the predicted evolutionary discharge trends are consistent with the previous simulations and experimental observations. Additionally, the constructed DNN shows good generalization performance for multiple input attributes, which indicates a great potential promise for vastly extending the range of discharge parameters. This study provides a useful paradigm for future explorations of machine learning-based methods in the field of atmospheric LTP simulation without high-cost calculation. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
34. Mental Manifestations and Biomarkers of Alcohol Consumption.
- Author
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Sarpe, Ana-Maria, Dodul, Cristina, Vlase, Emil-Andrei, Onișor, Cristian, Niculet, Elena, Ciobotaru, Octavian Catalin, and Drima, Eduard Polea
- Subjects
ALCOHOLISM ,PSYCHOTHERAPY ,ALCOHOL drinking ,BLOOD alcohol ,BIOMARKERS - Abstract
The purpose of this study is to examine healthcare usage, morbidities, and alcohol consumption monitoring in patients before a diagnosis of mental manifestations to assist in the early identification of individuals at risk. Biological markers of alcoholism are separated into two groups: those biological variables that highlight with great confidence and validate the presence of a predisposition to alcoholism, also called trait markers, or those that highlight alcohol consumption, called markers of alcoholism ("status markers"). Biomarkers are the true "gold standard" for the diagnosis of alcoholism. They are valuable for tracking evolution and progress during biological and psychological therapy and for highlighting relapse. This review compiles the existing data from research on healthcare utilization, comorbidities, and alcohol consumption monitoring in patients before a diagnosis of mental manifestations to aid in the early identification of individuals at risk. This documentary study took place over three to four months by searching for terms on the Science Direct platform, PubMed, Web of Science, and Google Scholar such as alcoholism, alcohol use disorders, alcohol abuse, and biomarkers. Studies reporting on the development, characteristics, and utilization of blood biomarkers for alcohol consumption were included in the search. The initial search included a number of 11.019 articles that contained the keywords biomarkers and alcohol. Finally, a total of 50 research articles were considered. I am involved in clinical studies, meta-analyses, reviews, and case studies regarding alcohol consumption detection, as well as potential alcohol markers. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
35. Assessment of Cognitive Function in Romanian Patients with Chronic Alcohol Consumption.
- Author
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Morega, Shandiz, Ionele, Claudiu-Marinel, Podeanu, Mihaela-Andreea, Florescu, Dan-Nicolae, and Rogoveanu, Ion
- Subjects
ESSENTIAL tremor ,ALCOHOL drinking ,FUNCTIONAL assessment ,NON-alcoholic fatty liver disease ,COGNITIVE ability ,ALCOHOL withdrawal syndrome - Abstract
Alcoholism presents a significant health concern with notable socioeconomic implications. Alcohol withdrawal syndrome (AWS) can manifest when individuals cease or drastically reduce their alcohol consumption after prolonged use. Non-alcoholic fatty liver disease (NAFLD) is characterized by substantial lipid accumulation in the liver cells of individuals with no history of alcohol consumption. There is evidence suggesting an association between cognitive impairment and both conditions. This study aimed to evaluate cognitive impairment in patients with NAFLD and AWS using the Mini-Mental State Examination (MMSE). This study involved 120 patients admitted to two hospitals in Craiova, Romania. Results indicated that patients with NAFLD did not exhibit cognitive impairment as measured by MMSE (Mean = 29.27, SD = 0.785). Conversely, patients with AWS showed more pronounced cognitive dysfunction, with a mean MMSE score at admission of 16.60 ± 4.097 and 24.60 ± 2.832 after 2 weeks under treatment with Vitamins B1 and B6 and Cerebrolysin. Additionally, our findings suggested that cognitive dysfunction among alcohol consumers was correlated with the severity of clinical symptoms, as demonstrated by the severity of tremors in our study. The two-week period under treatment and alcohol withdrawal was insufficient for cognitive function to return to normal levels. Observational studies on longer periods of time are advised. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
36. Biochemical, Hematological, Inflammatory, and Gut Permeability Biomarkers in Patients with Alcohol Withdrawal Syndrome with and without Delirium Tremens.
- Author
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Melamud, Mark M., Bobrik, Daria V., Brit, Polina I., Efremov, Ilia S., Buneva, Valentina N., Nevinsky, Georgy A., Akhmetova, Elvina A., Asadullin, Azat R., and Ermakov, Evgeny A.
- Subjects
ALCOHOL withdrawal syndrome ,LEUKOCYTE count ,PLATELET lymphocyte ratio ,BIOMARKERS ,BLOOD sedimentation - Abstract
Background: Delirium Tremens (DT) is known to be a serious complication of alcohol withdrawal syndrome (AWS). Neurotransmitter abnormalities, inflammation, and increased permeability are associated with the pathogenesis of AWS and DT. However, the biomarkers of these conditions are still poorly understood. Methods: In this work, biochemical, hematologic, inflammatory, and gut permeability biomarkers were investigated in the following three groups: healthy controls (n = 75), severe AWS patients with DT (n = 28), and mild/moderate AWS without DT (n = 97). Blood sampling was performed after resolution of the acute condition (on 5 ± 1 day after admission) to collect clinical information from patients and to investigate associations with clinical scales. Biomarker analysis was performed using automated analyzers and ELISA. Inflammatory biomarkers included the erythrocyte sedimentation rate (ESR), high-sensitivity C-reactive protein (hsCRP), and platelet-to-lymphocyte ratio (PLR). Results: Among the biochemical biomarkers, only glucose, total cholesterol, and alanine aminotransferase (ALT) changed significantly in the analyzed groups. A multiple regression analysis showed that age and ALT were independent predictors of the CIWA-Ar score. Hematologic biomarker analysis showed an increased white blood cell count, and the elevated size and greater size variability of red blood cells and platelets (MCV, RDWc, and PDWc) in two groups of patients. Gut permeability biomarkers (FABP2, LBP, and zonulin) did not change, but were associated with comorbid pathologies (alcohol liver disease and pancreatitis). The increase in inflammatory biomarkers (ESR and PLR) was more evident in AWS patients with DT. Cluster analysis confirmed the existence of a subgroup of patients with evidence of high inflammation, and such a subgroup was more frequent in DT patients. Conclusions: These findings contribute to the understanding of biomarker variability in AWS patients with and without DT and support the heterogeneity of patients by the level of inflammation. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
37. «Vi er ingen selskapsdamer»: Førstelinjeansattes legitimering av nedprioritering av omsorg i hjemmetjenestene.
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Sundsbø, Astrid O.
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- 2024
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38. Standardisering og variasjon i kommunale forskrifter for tildeling av langtids sykehjemsplass.
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Rødal, Jorunn Hoås, Hansson, Lisa, and Kirchhoff, Ralf
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- 2024
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- View/download PDF
39. Needs assessment in long-term care: expression of national principles for priority setting in service allocation.
- Author
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Pedersen, Ann Katrin Blø, Skinner, Marianne Sundlisæter, and Sogstad, Maren
- Subjects
LONG-term health care ,NEEDS assessment ,ADULT care services ,OLDER people ,ACTIVE aging ,ALLOCATION of organs, tissues, etc. - Abstract
Background: Long-term care services for older adults are characterised by increasing needs and scarce resources. Political strategies have led to the reorganisation of long-term care services, with an increased focus on "ageing in place" and efficient use of resources. There is currently limited research on the processes by which resource allocation decisions are made by service allocators of long-term care services for older adults. The aim of this study is to explore how three political principles for priority setting in long-term care, resource, severity and benefit, are expressed in service allocation to older adults. Methods: This qualitative study uses data from semi-structured individual interviews, focus groups and observations of service allocators who assess needs and assign long-term care services to older adults in Norway. The data were supplemented with individual decision letters from the allocation office, granting or denying long-term care services. The data were analysed using reflexive thematic analysis. Results: The allocators drew on all three principles for priority setting when assessing older adults' long-term care needs and allocating services. We found that the three principles pushed in different directions in the allocation process. We identified six themes related to service allocators' expression of the principles: (1) lowest effective level of care as a criterion for service allocation (resource), (2) blanket allocation of low-cost care services (resource), (3) severity of medical and rehabilitation needs (severity), (4) severity of care needs (severity), (5) benefit of generous service allocation (benefit) and (6) benefit of avoiding services (benefit). Conclusions: The expressions of the three political principles for priority setting in long-term care allocation are in accordance with broader political trends and discourses regarding "ageing in place", active ageing, an investment ideology, and prioritising those who are "worse off". Increasing attention to the rehabilitation potential of older adults and expectations that they will take care of themselves increase the risk of not meeting frail older adults' care needs. Additionally, difficulties in defining the severity of older adults' complex needs lead to debates regarding "worse off" versus potentiality in future long-term care services allocation. Trial registration: Not applicable. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
40. Inhibition of the Sodium–Calcium Exchanger Reverse Mode Activity Reduces Alcohol Consumption in Rats.
- Author
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Silva-Cardoso, Gleice Kelli and N'Gouemo, Prosper
- Subjects
ALCOHOL drinking ,ALCOHOLISM ,DRINKING (Physiology) ,RATS ,ANIMAL training - Abstract
Excessive and uncontrolled consumption of alcohol can cause alcohol use disorder (AUD), but its pharmacological mechanisms are not fully understood. Inhibiting the reverse mode activity of the sodium–calcium exchanger (NCX) can reduce the risk of alcohol withdrawal seizures, suggesting that NCX could play a role in controlling alcohol consumption. Here, we investigated how two potent inhibitors of NCX reverse mode activity, SN-6 (NCX1) and KB-R7943 (NCX3), affect voluntary alcohol consumption in adult male and female rats using the intermittent alcohol access two-bottle choice paradigm. Initially, animals were trained to drink 7.5% ethanol and water for four weeks before administering SN-6 and KB-R7934. Afterward, their alcohol intake, preference, and water intake were recorded 2 and 24 h after exposure to water and 7.5% ethanol. SN-6 significantly reduced alcohol consumption by 48% in male and 36% in female rats without affecting their water intake. Additionally, SN-6 significantly reduced alcohol preference in females by 27%. However, KB-R7943 reduced alcohol consumption by 42% in female rats and did not affect alcohol preference or water intake. These findings suggest that alcohol exposure increased NCX reverse activity, and targeting NCX1 could be an effective strategy for reducing alcohol consumption in subjects susceptible to withdrawal seizures. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
41. The ecosystem of human capital in care homes.
- Author
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Kejžar, Anamarija and Turunen, Katri Maria
- Published
- 2024
- Full Text
- View/download PDF
42. Service Allocators' Experiences of Ethical Dilemmas and Strategies in Long-Term Care: A Qualitative Study.
- Author
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Pedersen, Ann Katrin Blø, Skinner, Marianne Sundlisæter, and Sogstad, Maren
- Abstract
The provision of long-term care services for older adults is characterised by increasing needs and scarce resources, leading to ethical dilemmas. This qualitative study explored the ethical dilemmas experienced by healthcare professionals when allocating long-term care services to older adults and the strategies used to handle ethical dilemmas. Data from semi-structured individual interviews, focus group interviews, and observations of service allocators assessing needs and assigning long-term care services to older adults were analysed using content analysis. The overarching theme was the struggle for safe and equitable service allocation. The identified dilemmas were: (i) Struggles with A Just Allocation of Services due to Limited Time and Trust, (ii) Pressure on Professional Values Concerning Safety and Dignity, and (iii) Difficulties in Prioritising One Group Over Another. The strategies to deal with ethical dilemmas were: (i) Assessing Needs Across the Entire Municipality, (ii) Ensuring Distance to Service Recipients, (iii) Working as a Team, and (iv) Interprofessional Decision-Making. Scarce resources, organisational limitations, and political expectations drive the ethical dilemmas in long-term care service allocation. An open public discussion regarding the acceptable minimum standard of long-term care is needed to reduce the ethical pressure on service allocators. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
43. Estimating volcanic ash emissions using retrieved satellite ash columns and inverse ash transport modeling using VolcanicAshInversion v1.2.1, within the operational eEMEP (emergency European Monitoring and Evaluation Programme) volcanic plume forecasting system (version rv4_17)
- Author
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Brodtkorb, André R., Benedictow, Anna, Klein, Heiko, Kylling, Arve, Nyiri, Agnes, Valdebenito, Alvaro, Sollum, Espen, and Kristiansen, Nina
- Subjects
VOLCANIC plumes ,VOLCANIC ash clouds ,VOLCANIC ash, tuff, etc. ,PARTICLE size distribution ,VOLCANIC eruptions - Abstract
Accurate modeling of ash clouds from volcanic eruptions requires knowledge about the eruption source parameters including eruption onset, duration, mass eruption rates, particle size distribution, and vertical-emission profiles. However, most of these parameters are unknown and must be estimated somehow. Some are estimated based on observed correlations and known volcano parameters. However, a more accurate estimate is often needed to bring the model into closer agreement with observations. This paper describes the inversion procedure implemented at the Norwegian Meteorological Institute for estimating ash emission rates from retrieved satellite ash column amounts and a priori knowledge. The overall procedure consists of five stages: (1) generate a priori emission estimates, (2) run forward simulations with a set of unit emission profiles, (3) collocate/match observations with emission simulations, (4) build system of linear equations, and (5) solve overdetermined systems. We go through the mathematical foundations for the inversion procedure, performance for synthetic cases, and performance for real-world cases. The novelties of this paper include a memory efficient formulation of the inversion problem, a detailed description and illustrations of the mathematical formulations, evaluation of the inversion method using synthetic known-truth data as well as real data, and inclusion of observations of ash cloud-top height. The source code used in this work is freely available under an open-source license and is able to be used for other similar applications. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
44. Over the Limit; Long-Term Seizure and Mortality Risk in Alcohol Withdrawal Seizures.
- Author
-
Widdess-Walsh, Peter
- Subjects
BRAIN tomography ,COMPUTED tomography ,DISEASE relapse ,ALCOHOLISM ,PROGNOSIS - Abstract
Long-Term Outcome of Alcohol Withdrawal Seizures Sansone G, Megevand P, Vulliémoz S, Corbetta M, Picard F, Seeck M. Eur J Neurol. 2024;31(1):e16075. doi:10.1111/ene.16075 Background and purpose: Alcohol withdrawal seizures (AWS) are a well-known complication of chronic alcohol abuse, but there is currently little knowledge of their long-term relapse rate and prognosis. The aims of this study were to identify risk factors for AWS recurrence and to study the overall outcome of patients after AWS. Methods: In this retrospective single-center study, we included patients who were admitted to the Emergency Department after an AWS between January 1, 2013 and August 10, 2021 and for whom an electroencephalogram (EEG) was requested. AWS relapses up until April 29, 2022 were researched. We compared history, treatment with benzodiazepines or antiseizure medications (ASMs), laboratory, EEG and computed tomography findings between patients with AWS relapse (r-AWS) and patients with no AWS relapse (nr-AWS). Results: A total of 199 patients were enrolled (mean age 53 ± 12 years; 78.9% men). AWS relapses occurred in 11% of patients, after a median time of 470.5 days. Brain computed tomography (n = 182) showed pathological findings in 35.7%. Risk factors for relapses were history of previous AWS (p = 0.013), skull fractures (p = 0.004) at the index AWS, and possibly epileptiform EEG abnormalities (p = 0.07). Benzodiazepines or other ASMs, taken before or after the index event, did not differ between the r-AWS and the nr-AWS group. The mortality rate was 2.9%/year of follow-up, which was 13 times higher compared to the general population. Risk factors for death were history of AWS (p < 0.001) and encephalopathic EEG (p = 0.043). Conclusions: Delayed AWS relapses occur in 11% of patients and are associated with risk factors (previous AWS >24 h apart, skull fractures, and pathological EEG findings) that also increase the epilepsy risk, that is, predisposition for seizures, if not treated. Future prospective studies are mandatory to determine appropriate long-term diagnostic and therapeutic strategies, in order to reduce the risk of relapse and mortality associated with AWS. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
45. Long‐term outcome of alcohol withdrawal seizures.
- Author
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Sansone, Giulio, Megevand, Pierre, Vulliémoz, Serge, Corbetta, Maurizio, Picard, Fabienne, and Seeck, Margitta
- Subjects
EPILEPSY ,SKULL fractures ,BRAIN tomography ,SEIZURES (Medicine) ,ALCOHOLISM ,COMPUTED tomography - Abstract
Background and purpose: Alcohol withdrawal seizures (AWS) are a well‐known complication of chronic alcohol abuse, but there is currently little knowledge of their long‐term relapse rate and prognosis. The aims of this study were to identify risk factors for AWS recurrence and to study the overall outcome of patients after AWS. Methods: In this retrospective single‐center study, we included patients who were admitted to the Emergency Department after an AWS between January 1, 2013 and August 10, 2021 and for whom an electroencephalogram (EEG) was requested. AWS relapses up until April 29, 2022 were researched. We compared history, treatment with benzodiazepines or antiseizure medications (ASMs), laboratory, EEG and computed tomography findings between patients with AWS relapse (r‐AWS) and patients with no AWS relapse (nr‐AWS). Results: A total of 199 patients were enrolled (mean age 53 ± 12 years; 78.9% men). AWS relapses occurred in 11% of patients, after a median time of 470.5 days. Brain computed tomography (n = 182) showed pathological findings in 35.7%. Risk factors for relapses were history of previous AWS (p = 0.013), skull fractures (p = 0.004) at the index AWS, and possibly epileptiform EEG abnormalities (p = 0.07). Benzodiazepines or other ASMs, taken before or after the index event, did not differ between the r‐AWS and the nr‐AWS group. The mortality rate was 2.9%/year of follow‐up, which was 13 times higher compared to the general population. Risk factors for death were history of AWS (p < 0.001) and encephalopathic EEG (p = 0.043). Conclusions: Delayed AWS relapses occur in 11% of patients and are associated with risk factors (previous AWS >24 h apart, skull fractures, and pathological EEG findings) that also increase the epilepsy risk, that is, predisposition for seizures, if not treated. Future prospective studies are mandatory to determine appropriate long‐term diagnostic and therapeutic strategies, in order to reduce the risk of relapse and mortality associated with AWS. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
46. A novel SLC20A2 mutation presenting with paroxysmal kinesigenic dyskinesia and epilepsy in a Chinese patient: a case report.
- Author
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Wang, Lijun, Ma, Jianfang, and Che, Xiangqian
- Published
- 2023
- Full Text
- View/download PDF
47. Infantile onset encephalomyopathy, retinopathy, optic atrophy, and mitochondrial DNA depletion associated with a novel pathogenic DHX16 variant.
- Author
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Hautakangas, Milla‐Riikka, Widgren, Paula, Korpelainen, Paavo, Kangas, Salla M., Komulainen, Tuomas, Vieira, Päivi, Rahikkala, Elisa, Pylkäs, Katri, Tuominen, Hannu, Kokkonen, Hannaleena, Miinalainen, Ilkka, Nadaf, Javad, Majewski, Jacek, Hinttala, Reetta, and Uusimaa, Johanna
- Subjects
MITOCHONDRIAL DNA ,ATROPHY ,RNA helicase ,SENSORINEURAL hearing loss ,SKELETAL muscle ,GENETIC variation - Abstract
We studied a patient with mitochondrial DNA depletion in skeletal muscle and a multiorgan phenotype, including fatal encephalomyopathy, retinopathy, optic atrophy, and sensorineural hearing loss. Instead of pathogenic variants in the mitochondrial maintenance genes, we identified previously unpublished variant in DHX16 gene, a de novo heterozygous c.1360C>T (p. Arg454Trp). Variants in DHX16 encoding for DEAH‐box RNA helicase have previously been reported only in five patients with a phenotype called as neuromuscular oculoauditory syndrome including developmental delay, neuromuscular symptoms, and ocular or auditory defects with or without seizures. We performed functional studies on patient‐derived fibroblasts and skeletal muscle revealing, that the DHX16 expression was decreased. Clinical features together with functional data suggest, that our patient's disease is associated with a novel pathogenic DHX16 variant, and mtDNA depletion could be a secondary manifestation of the disease. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
48. Moral distress experienced by care leaders' in older adult care: A qualitative study.
- Author
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Ahokas, Fanny and Hemberg, Jessica
- Subjects
WORK environment ,ETHICS ,RESEARCH methodology ,LEADERS ,INTERVIEWING ,EXPERIENCE ,QUALITATIVE research ,NURSES ,CONTENT analysis ,THEMATIC analysis ,PSYCHOLOGICAL distress ,ELDER care ,REFLECTION (Philosophy) - Abstract
Background: Many healthcare professionals have left their professions recently because of increased moral distress, and the COVID‐19 pandemic has had a further major impact on the ever‐changing healthcare environment. Aim: The purpose of the study was to examine care leaders' experiences of moral distress in their daily work in older adult care. Methodology: A qualitative design was used. The data consisted of texts from interviews with care leaders (N = 8) in an older adult care context. Content analysis was used to analyse the data. Findings: Five themes emerged: (1) moral distress arises from a lack of time, (2) moral distress contributes to a sense of inadequacy but also a sense of responsibility, (3) moral distress arises from an imbalance in values, (4) increased knowledge and open discussion help reduce moral distress and (5) reflection, increased support and increased resources can reduce moral distress. Conclusion: Moral distress is something that care leaders, according to this study, experience daily in an older adult care context and it is considered to have increased. Care leaders can experience moral distress from a lack of time; patient‐related, relative‐related or other ethically difficult situations or an imbalance between own values and an organisation's, other caregivers', patients' and/or patients' relatives values. Increased staffing resources, more knowledge (training and lectures) and time for reflection individually, in groups or with an outside expert could increase care leaders' insights into and ability to reduce moral distress. Although situations that are characterised by moral distress are burdensome, care leaders have the opportunity to learn from such situations through reflection and discussion and can develop strategies for future ethical challenges. Future research could focus on exploring caregivers' experiences of moral distress. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
49. Optimization Techniques for GPU Programming.
- Author
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HIJMA, PIETER, HELDENS, STIJN, SCLOCCO, ALESSIO, VAN WERKHOVEN, BEN, and BAL, HENRI E.
- Subjects
MATHEMATICAL optimization ,AUTONOMOUS vehicles - Abstract
In the past decade, Graphics Processing Units have played an important role in the field of high-performance computing and they still advance new fields such as IoT, autonomous vehicles, and exascale computing. It is therefore important to understand how to extract performance from these processors, something that is not trivial. This survey discusses various optimization techniques found in 450 articles published in the last 14 years. We analyze the optimizations from different perspectives which shows that the various optimizations are highly interrelated, explaining the need for techniques such as auto-tuning. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
50. Psychological resilience and competence: key promoters of successful aging and flourishing in late life.
- Author
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Zábó, Virág, Csiszar, Anna, Ungvari, Zoltan, and Purebl, György
- Subjects
SUCCESSFUL aging ,PSYCHOLOGICAL resilience ,PSYCHOLOGICAL factors ,MENTAL health ,PSYCHOLOGICAL aspects of aging ,AGING - Abstract
Many individuals, both in the public and within the field of psychology, often perceive aging as a burden that negatively impacts intellectual and mental health. Our present study aims to challenge this notion by identifying the crucial components of positive mental health in later life. These components not only promote positive mental health but also actively contribute to it, even under difficult circumstances. To accomplish this, we first offer a concise review of well-being and mental health models that highlight the psychological aspects of flourishing in late life. We then introduce a psychological competence-based model for positive mental health, which aligns with the concept of positive aging. Subsequently, we present a measurement tool suitable for practical applications. Finally, we provide a comprehensive overview of positive aging, drawing on methodological guidelines and existing research findings concerning sustainable positive mental health in later life. We examine the evidence indicating that psychological resilience (the capacity to adapt and recover from adversity or stress) and competence (skills and abilities to effectively cope with challenges across various life domains) significantly contribute to slowing down biological aging processes. Furthermore, we discuss insights into the relationship between psychological factors and aging derived from research on Blue Zones (regions characterized by a higher proportion of individuals experiencing longer, healthier lives). [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
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