48,751 research outputs found

    Computer Simulations of Cosmic Reionization

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    The cosmic reionization of hydrogen was the last major phase transition in the evolution of the universe, which drastically changed the ionization and thermal conditions in the cosmic gas. To the best of our knowledge today, this process was driven by the ultra-violet radiation from young, star-forming galaxies and from first quasars. We review the current observational constraints on cosmic reionization, as well as the dominant physical effects that control the ionization of intergalactic gas. We then focus on numerical modeling of this process with computer simulations. Over the past decade, significant progress has been made in solving the radiative transfer of ionizing photons from many sources through the highly inhomogeneous distribution of cosmic gas in the expanding universe. With modern simulations, we have finally converged on a general picture for the reionization process, but many unsolved problems still remain in this young and exciting field of numerical cosmology.Comment: Invited Review to appear on Advanced Science Letters (ASL), Special Issue on Computational Astrophysics, edited by Lucio Maye

    An Investigation of How Lighting and Rendering Technology Affects Filmmaking Relative to Arnold’s Transition to a GPU-Based Path-Tracer

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    Computer Graphic (CGI) technology enables artists to explore a broad spectrum of approaches and styles, from photorealistic to abstract, expanding the boundaries of traditional aesthetic choices. Recent years have witnessed of 3D-CGI production shift towards greater physical fidelity driven by technological developments as well as consumer demand for realistic visuals; this trend can be found across various creative fields like film, video games, and virtual reality experiences with high-quality textures, lighting, rendering, and physics simulations providing enhanced levels of immersion for users. Arnold is one of the famous rendering engines assisting artists to be more creative while producing photorealistic images. Moreover, Arnold renders the engine as one of the main path-tracing renderers and contributes significantly to more fantastic photorealistic productions. Also, Arnold renders not only Support CPU render but also support GPU rendering to take full advantage of faster computation times and real-time interactivity, among many other advantages. Because of that, this study investigates how new technology like developed GPUs helps artists and filmmakers better comprehend 3D rendering solutions that impact their workflows. On the other hand, philosophically exploring the relationship between making a creative decision and technology within 3D photorealistic rendering reveals an intricate yet dynamic relationship that informs the creative processes of both independent artists and small studios alike. This interaction serves as a reminder that Art is driven forward by its creator\u27s creative energy rather than simply technological capabilities; artists and studios can continue pushing limits by embracing this complex dialogue between creativity and tech, opening new paths within digital Art\u27s fast-evolving realm

    Performance Evaluation of Adaptive Scientific Applications using TAU

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    Fueled by increasing processor speeds and high speed interconnection networks, advances in high performance computer architectures have allowed the development of increasingly complex large scale parallel systems. For computational scientists, programming these systems efficiently is a challenging task. Understanding the performance of their parallel applications i

    Design Space Exploration of Next-Generation HPC Machines

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    The landscape of High Performance Computing (HPC) system architectures keeps expanding with new technologies and increased complexity. With the goal of improving the efficiency of next-generation large HPC systems, designers require tools for analyzing and predicting the impact of new architectural features on the performance of complex scientific applications at scale. We simulate five hybrid (MPI+OpenMP) applications over 864 architectural proposals based on stateof-the-art and emerging HPC technologies, relevant both in industry and research. This paper significantly extends our previous work with MUltiscale Simulation Approach (MUSA) enabling accurate performance and power estimations of largescale HPC systems. We reveal that several applications present critical scalability issues mostly due to the software parallelization approach. Looking at speedup and energy consumption exploring the design space (i.e., changing memory bandwidth, number of cores, and type of cores), we provide evidence-based architectural recommendations that will serve as hardware and software codesign guidelines.Preprin
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