328,965 research outputs found
GPU-accelerated depth map generation for X-ray simulations of complex CAD geometries
No full textInteractive x-ray simulations of complex computer-aided design (CAD) models can provide valuable insights for better interpretation of the defect signatures such as porosity from x-ray CT images. Generating the depth map along a particular direction for the given CAD geometry is the most compute-intensive step in x-ray simulations. We have developed a GPU-accelerated method for real-time generation of depth maps of complex CAD geometries. We preprocess complex components designed using commercial CAD systems using a custom CAD module and convert them into a fine user-defined surface tessellation. Our CAD module can be used by different simulators as well as handle complex geometries, including those that arise from complex castings and composite structures. We then make use of a parallel algorithm that runs on a graphics processing unit (GPU) to convert the finely-tessellated CAD model to a voxelized representation. The voxelized representation can enable heterogeneous modeling of the volume enclosed by the CAD model by assigning heterogeneous material properties in specific regions. The depth maps are generated from this voxelized representation with the help of a GPU-accelerated ray-casting algorithm. The GPU-accelerated ray-casting method enables interactive (> 60 frames-per-second) generation of the depth maps of complex CAD geometries. This enables arbitrarily rotation and slicing of the CAD model, leading to better interpretation of the x-ray images by the user. In addition, the depth maps can be used to aid directly in CT reconstruction algorithms.This proceeding may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This proceeding appeared in Grandin, Robert J., Gavin Young, Stephen D. Holland, and Adarsh Krishnamurthy. "GPU-accelerated depth map generation for X-ray simulations of complex CAD geometries." In AIP Conference Proceedings, vol. 1949, no. 1, p. 190002. AIP Publishing LLC, 2018, and may be found at
DOI: 10.1063/1.5031636.
Copyright 2018 Author(s).
Posted with permission
How Debt Markets have Malfunctioned in the Crisis
No full textThis article explains how debt markets have malfunctioned in the crisis, with deleterious consequences for the real economy. I begin with a quick overview of debt markets. I then discuss three areas that are crucial in all debt markets decisions: risk capital and risk aversion, repo financing and haircuts, and counterparty risk. In each of these areas, feedback effects can arise, so that less liquidity and a higher cost for finance can reinforce each other in a contagious spiral. I document the remarkable rise in the premium that investors placed on liquidity during the crisis. Next, I show how these issues caused debt markets to break down: fundamental values and market values seemed to diverge across several markets and products that were far removed from the “toxic” subprime mortgage assets at the root of the crisis. Finally, I discuss briefly four steps that the Federal Reserve took to ease the crisis, and how each was geared to a specific systemic fault that arose during the crisis.
A Newly Discovered Paramāra Inscription of Ajayavarma from Sohāgpūr - A Brief Note
No full textRajesh Mehar and S. Krishnamurthy, "A Newly Discovered Paramāra Inscription of Ajayavarma from Sohāgpūr - A Brief Note," Bhāratīya Purābhilēkha Patikā 43 (2018): 103-112
Meena Krishnamurthy and Political Emotions
No full textWhat are the roles that emotions play in politics and civic life? Do feelings like rage, happiness or tension get in the way of political progress, or are they important tools in the fight for social justice? On this episode of Examining Ethics, Christiane interviews Meena Krishnamurthy, a philosopher whose recent work explores the value of political emotions in Martin Luther King Jr.’s writing and activism
Incorporation of composite defects from ultrasonic NDE into CAD and FE models
No full textFiber-reinforced composites are widely used in aerospace industry due to their combined properties of high strength and low weight. However, owing to their complex structure, it is difficult to assess the impact of manufacturing defects and service damage on their residual life. While, ultrasonic testing (UT) is the preferred NDE method to identify the presence of defects in composites, there are no reasonable ways to model the damage and evaluate the structural integrity of composites. We have developed an automated framework to incorporate flaws and known composite damage automatically into a finite element analysis (FEA) model of composites, ultimately aiding in accessing the residual life of composites and make informed decisions regarding repairs. The framework can be used to generate a layer-by-layer 3D structural CAD model of the composite laminates replicating their manufacturing process. Outlines of structural defects, such as delaminations, are automatically detected from UT of the laminate and are incorporated into the CAD model between the appropriate layers. In addition, the framework allows for direct structural analysis of the resulting 3D CAD models with defects by automatically applying the appropriate boundary conditions. In this paper, we show a working proof-of-concept for the composite model builder with capabilities of incorporating delaminations between laminate layers and automatically preparing the CAD model for structural analysis using a FEA software.This proceeding may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This proceeding appeared in Bingol, Onur Rauf, Bryan Schiefelbein, Robert J. Grandin, Stephen D. Holland, and Adarsh Krishnamurthy. "Incorporation of composite defects from ultrasonic NDE into CAD and FE models." AIP Conference Proceedings 1806, no. 1, (2017): 150004. , and may be found at DOI: 10.1063/1.4974728. Posted with permission.</p
Probiotics in Caries Prevention
No full textHow to cite this article: Kumar VN, Krishnamurthy M, Poorni S, Patil S, Raj AT. Probiotics in Caries Prevention. J Contemp Dent Pract 2018;19(2):123-124.</jats:p
Media Access Protocols for use with Smart Array Antennas to Enable Wireless Multimedia Applications
No full textMujeres toman el poder de la tierra: acceso a la tierra como una estrategia de empoderamiento de mujeres indígenas en Guatemala
No full textDe conformidad con el presente estudio, en Guatemala las personas más pobres y marginadas son las mujeres indígenas. De acuerdo con el PNUD, de las mujeres indígenas, 80% están ligadas a la tierra y a la agricultura por diversas formas. Sin embargo, las mujeres sólo representan un 6,5% entre l@s proprietari@s de la tierra. La mayoría de las veces esa conexión compleja del mundo indígena con la tierra no es reconocida por las estadísticas oficiales porque apenas están remuneradas por su trabajo en la agricultura. El presente estudio, realizado por la politóloga Archana Krishnamurthy se enfoca en la realidad guatemalteca y la exclusión masiva de las mujeres indígenas en la tenencia de la tierra. Recoge, con base en casos concretos las experiencias que diversas comunidades han tenido con los programas de tierra y explica en qué medida y de qué forma las mujeres pueden participar
Revisiting the slow manifold of the Lorenz-Krishnamurthy quintet
No full textThe slow-manifold for the Lorenz-Krishnamurthy model has been studied. By minimizing the evolution rate we ¯nd that the analytical functions for the fast variables are devoid of high frequency oscillations. However upon solving this model with initial values of the fast variables obtained from the analytical functions, the LK model exhibits high frequency oscillations. Upon using the time derivatives of the analytic functions for computing the evolution of fast variables, we ¯nd a slow-manifold in the neighbourhood of the LK model. Minimization of evolution rate does not guarantee the invariance of the manifold. Using a locally linear approximate reduction scheme, the invariance can be maintained. However, the solutions so obtained do develop high frequency oscillations. The onset of these high frequency oscillations is delayed vis-a-vis other previous studies. These methods have potential to be used in improving the predictions of weather systems
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