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Transcranial magnetic stimulation (TMS) is a stimulation method in which a magnetic coil generates a magnetic field in an area of interest in the brain. This magnetic field induces an electric field that modulates neuronal activity. The spatial distribution of the induced electric field is determined by the geometry and location of the coil relative to the(More)
In this work, we visualize high-dimensional particle simulation data using a suite of scatterplot-based visualiza-tions coupled with interactive selection tools. We use traditional 2D and 3D projection scatterplots as well as a novel oriented-disk rendering style to convey various information about the data. Interactive selection tools allow physicists to(More)
—The accuracy of first-order Euler and higher-order time-integration algorithms for grid-based Langevin equations collision models in a specific relaxation test problem is assessed. We show that statistical noise errors can overshadow time-step errors and argue that statistical noise errors can be conflated with time-step effects. Using a higher-order(More)
This paper is a critique of Norman Daniels' and James Sabin's 'Accountability for Reasonableness' framework for making priority-setting decisions in health care in the face of widespread disagreement about values. Accountability for Reasonableness has been rapidly gaining worldwide acceptance, arguably to the point of becoming the dominant paradigm in the(More)
Vlasov simulations can for some situations be a valuable alternative to PIC simulations for the study of intense beam propagation. However, as they rely on a phase-space grid which is fixed for the whole simulation, important computing effort can be wasted in zones where no particles are present at some given time. In order to overcome this drawback, we(More)
Plasma simulations are often rendered challenging by the disparity of scales in time and in space which must be resolved. When these disparities are in distinctive zones of the simulation region, a method which has proven to be effective in other areas (e.g., fluid dynamics simulations) is the mesh refinement technique. We briefly discuss the challenges(More)
Although transcranial magnetic stimulation (TMS) is a popular tool for both basic research and clinical applications, its actions on nerve cells are only partially understood. We have previously predicted, using compartmental modeling, that magnetic stimulation of central nervous system neurons depolarized the soma followed by initiation of an action(More)
Objective Toward the goal of maximizing the impact of computer modeling on the design of future particle accelerators and the development of new accelerator techniques & technologies, this white paper presents the rationale for: (a) strengthening and expanding programmatic activities in accelerator modeling science within the Department of Energy (DOE)(More)
Fundamental to efficient computation at the exascale will be methods for computationally modeling complex physical systems on platforms with likely billion-­‐way hardware and heterogeneous components. A broad family of computations that employ discrete-­‐particle methods already enjoys good parallel performance; however, many applications are constrained by(More)