Towards composition of verified hardware devices

Computers are being used where no affordable level of testing is adequate. Safety and life critical systems must find a replacement for exhaustive testing to guarantee their correctness. Through a mathematical proof, hardware verification research has focused on device verification and has largely ignored system composition verification. To address these deficiencies, we examine how the current hardware verification methodology can be extended to verify complete systems

Direct brain recordings reveal continuous encoding of structure in random stimuli

The brain excels at processing sensory input, even in rich or chaotic environments. Mounting evidence attributes this to the creation of sophisticated internal models of the environment that draw on statistical structures in the unfolding sensory input. Understanding how and where this modeling takes place is a core question in statistical learning and predictive processing. In this context, we address the role of transitional probabilities as an implicit structure supporting the encoding of a random auditory stream. Leveraging information-theoretical principles and the high spatiotemporal resolution of intracranial electroencephalography, we analyzed the trial-by-trial high-frequency activity representation of transitional probabilities. This unique approach enabled us to demonstrate how the brain continuously encodes structure in random stimuli and revealed the involvement of a network outside of the auditory system, including hippocampal, frontal, and temporal regions. Linking the frame-works of statistical learning and predictive processing, our work illuminates an implicit process that can be crucial for the swift detection of patterns and unexpected events in the environment.Fil: Fuhrer, Julian. University of Oslo; NoruegaFil: Kyrre, Glette. University of Oslo; NoruegaFil: Ivanovic, Jugoslav. University of Oslo; NoruegaFil: Gunnar Larsson, Pål. University of Oslo; NoruegaFil: Bekinschtein, Tristán Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. University of Cambridge; Reino UnidoFil: Kochen, Sara Silvia. Universidad Nacional Arturo Jauretche. Unidad Ejecutora de Estudios en Neurociencias y Sistemas Complejos. Provincia de Buenos Aires. Ministerio de Salud. Hospital Alta Complejidad en Red El Cruce Dr. Néstor Carlos Kirchner Samic. Unidad Ejecutora de Estudios en Neurociencias y Sistemas Complejos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Unidad Ejecutora de Estudios en Neurociencias y Sistemas Complejos; ArgentinaFil: Knight, Robert T.. University of California at Berkeley; Estados UnidosFil: Tørresen, Jim. University of Oslo; NoruegaFil: Solbakk, Anne Kristin. University of Oslo; Noruega. Helgeland Hospital; NoruegaFil: Endestad, Tor. University of Oslo; Noruega. Helgeland Hospital; NoruegaFil: Blenkmann, Alejandro Omar. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. University of Oslo; Norueg

An adaptive Cartesian embedded boundary approach for fluid simulations of two- and three-dimensional low temperature plasma filaments in complex geometries

We review a scalable two- and three-dimensional computer code for low-temperature plasma simulations in multi-material complex geometries. Our approach is based on embedded boundary (EB) finite volume discretizations of the minimal fluid-plasma model on adaptive Cartesian grids, extended to also account for charging of insulating surfaces. We discuss the spatial and temporal discretization methods, and show that the resulting overall method is second order convergent, monotone, and conservative (for smooth solutions). Weak scalability with parallel efficiencies over 70\% are demonstrated up to 8192 cores and more than one billion cells. We then demonstrate the use of adaptive mesh refinement in multiple two- and three-dimensional simulation examples at modest cores counts. The examples include two-dimensional simulations of surface streamers along insulators with surface roughness; fully three-dimensional simulations of filaments in experimentally realizable pin-plane geometries, and three-dimensional simulations of positive plasma discharges in multi-material complex geometries. The largest computational example uses up to $800$ million mesh cells with billions of unknowns on $4096$ computing cores. Our use of computer-aided design (CAD) and constructive solid geometry (CSG) combined with capabilities for parallel computing offers possibilities for performing three-dimensional transient plasma-fluid simulations, also in multi-material complex geometries at moderate pressures and comparatively large scale.Comment: 40 pages, 21 figure

Tourism Dependency and its Correlation to Selected Socioeconomic Indicators in Utah

This paper investigates the relationship between tourism and well being, or quality-of-life, within eighteen counties in Utah. To evaluate the relationship, comparisons of the counties\u27 differing levels of tourism versus their levels of welfare are necessary. To make these comparisons, three basic steps were followed. First, a social ordering model was derived. The proposed social ordering model was based upon Maslow\u27s theory of the hierarchy of human needs. By utilizing his theory, both economic and noneconomic indicators were identified, and a basis was provided upon which to judge the differing positions of well-being. Factor analysis was applied to this model in order to aggregate the indicators and derive a single quality-of-life index. Second, measurement of tourism was developed. A direct measurement of the level of tourist activity was not available. An indirect indicator of tourism was estimated by taking the proportion of total gross taxable revenue earned by eating and drinking establishments and taxable room sales. The derived indirect variable was more reflective of comparative tourism dependency levels than of the actual level of tourism. Therefore, the variable was renamed tourism dependency. Third, the correlation between quality-of-life and tourism dependency was calculated. A Pearson correlation coefficient test was performed from which initial results suggested a potentially strong negative relationship between the particular qualifiers of well-being used here and tourism. It was apparent that thE two variables that could be defined by certain available indicators were not perfect measurements of the proposed variables, but aspects or components of the desired variables. Each reflected certain attributes of the proposed variables, but not the total concept. A possible explanation for the strong inverse relationship between the qualifiers of quality of life and tourism in this study may be each county\u27s potential for economic diversification. Other studies have shown that areas that are dependent upon a single resource may experience higher levels of economic, demographic, and social instability as compared to those areas with a more diverse economic base. These factors, which in this model would lead to lower values for the calculated quality-of- life indicator in those counties, were estimated to be more tourist dependent

PERFORMANCE OPTIMIZATION OF A STRUCTURED CFD CODE - GHOST ON COMMODITY CLUSTER ARCHITECTURES

This thesis focuses on optimizing the performance of an in-house, structured, 2D CFD code – GHOST, on commodity cluster architectures. The basic philosophy of the work is to optimize the cache usage of the code by implementing efficient coding techniques without changing the underlying numerical algorithm. Various optimization techniques that were implemented and the resulting changes in performance have been presented. Two techniques, external and internal blocking that were implemented earlier to tune the performance of this code have been reviewed. What follows is further tuning effort in order to circumvent the problems associated with using the blocking techniques. Later, to establish the universality of the optimization techniques, testing has been done on more complicated test case. All the techniques presented in this thesis have been tested on steady, laminar test cases. It has been proved that optimized versions of the code achieve better performances on variety of commodity cluster architectures chosen in this study

High-resolution numerical simulation and analysis of Mach reflection structures in detonation waves in low-pressure H₂:O₂:Ar mixtures: a summary of results obtained with adaptive mesh refinement framework AMROC

Numerical simulation can be key to the understanding of the multidimensional nature of transient detonation waves. However, the accurate approximation of realistic detonations is demanding as a wide range of scales needs to be resolved. This paper describes a successful solution strategy that utilizes logically rectangular dynamically adaptive meshes. The hydrodynamic transport scheme and the treatment of the nonequilibrium reaction terms are sketched. A ghost fluid approach is integrated into the method to allow for embedded geometrically complex boundaries. Large-scale parallel simulations of unstable detonation structures of Chapman-Jouguet detonations in low-pressure hydrogen-oxygen-argon mixtures demonstrate the efficiency of the described techniques in practice. In particular, computations of regular cellular structures in two and three space dimensions and their development under transient conditions, that is, under diffraction and for propagation through bends are presented. Some of the observed patterns are classified by shock polar analysis, and a diagram of the transition boundaries between possible Mach reflection structures is constructed

Detailed Simulations of Shock-Bifurcation and Ignition of an Argon-diluted Hydrogen/Oxygen Mixture in a Shock Tube

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106508/1/AIAA2013-538.pd

Scarcity in IP addresses: IPv4 Address Transfer Markets and the Regional Internet Address Registries

We are running out of Internet addresses. This paper evaluates address transfer policies that Internet governance agencies are considering as a response to the depletion of the IPv4 address space. The paper focuses on proposals to allow organizations holding IPv4 addresses to sell address blocks to other organizations willing to buy them. This paper analyzes the economics of the proposed transfer policies, and conducts a systematic comparison of the policies proposed in the three main world Internet regions

Evaluation of the 3-D finite difference implementation of the acoustic diffusion equation model on massively parallel architectures

The diffusion equation model is a popular tool in room acoustics modeling. The 3-D Finite Difference (3D-FD) implementation predicts the energy decay function and the sound pressure level in closed environments. This simulation is computationally expensive, as it depends on the resolution used to model the room. With such high computational requirements, a high-level programming language (e.g., Matlab) cannot deal with real life scenario simulations. Thus, it becomes mandatory to use our computational resources more efficiently. Manycore architectures, such as NVIDIA GPUs or Intel Xeon Phi offer new opportunities to enhance scientific computations, increasing the performance per watt, but shifting to a different programming model. This paper shows the roadmap to use massively parallel architectures in a 3D-FD simulation. We evaluate the latest generation of NVIDIA and Intel architectures. Our experimental results reveal that NVIDIA architectures outperform by a wide margin the Intel Xeon Phi co-processor while dissipating approximately 50 W less (25%) for large-scale input problems.Ingeniería, Industria y Construcció