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The influence of finite ion temperature on plasma blob dynamics

PLASMA PHYSICS AND CONTROLLED FUSION 2015年第1期57卷

作者： Manz, P. Birkenmeier, G. Carralero, D. Fuchert, G. Mueller, H. W. Mueller, S. H. Scott, B. D. Stroth, U. Ribeiro, T. T. Wolfrum, E. Tech Univ Munich Phys Dept E28 D-85748 Garching Germany Max Planck Inst Plasma Phys D-85748 Garching Germany Univ Lorraine IJL CNRS UMR 7198 F-40239 Vandoeuvre Les Nancy France Univ Calif San Diego Ctr Momentum Transport & Flow Org San Diego CA 92103 USA

In the scrape-off layer of magnetically confined fusion devices, the ion temperature is at least as high as the electron temperature and usually even much higher. The effects of the finite ion temperature enhance the blob drive and modify the vorticity. Recently developed scaling laws for blob velocity independent of its size, based on the full drift-interchange-Alfven fluid equations are compared with recent experiments on the ASDEX Upgrade tokamak and gyrofluid simulations, showing remarkable agreement for the blob sizes and reasonable agreement for the blob velocities.

关键词： scrape-off layer transport blobs ion temperature finite Lamor radius effects

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Automated detection of microaneurysms using scale-adapted blob analysis and semi-adapted blob analysis and semi-supervised learning

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COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2014年第1期114卷 1-10页

作者： Adal, Kedir M. Sidibe, Desire Ali, Sharib Chaum, Edward Karnowski, Thomas P. Meriaudeau, Fabrice Univ Bourgogne CNRS Lab Le2i UMR 6306 F-71200 Le Creusot France U Tennessee Hlth Sci Ctr Hamilton Eye Inst Memphis TN USA Oak Ridge Natl Lab Oak Ridge TN USA

Despite several attempts, automated detection of microaneurysm (MA) from digital fundus images still remains to be an open issue. This is due to the subtle nature of MAs against the surrounding tissues. In this paper, the microaneurysm detection problem is modeled as finding interest regions or blobs from an image and an automatic local-scale selection technique is presented. Several scale-adapted region descriptors are introduced to characterize these blob regions. A semi-supervised based learning approach, which requires few manually annotated learning examples, is also proposed to train a classifier which can detect true MAs. The developed system is built using only few manually labeled and a large number of unlabeled retinal color fundus images. The performance of the overall system is evaluated on Retinopathy Online Challenge (ROC) competition database. A competition performance measure (CPM) of 0.364 shows the competitiveness of the proposed system against state-of-the art techniques as well as the applicability of the proposed features to analyze fundus images. (C) 2013 Elsevier Ireland Ltd. All rights reserved.

关键词： Microaneurysms Diabetic retinopathy Fundus image Semi-supervised learning blobs Scale-space

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Discontinuous Galerkin methods for plasma physics in the scrape-off layer of tokamaks

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JOURNAL OF COMPUTATIONAL PHYSICS 2014年 274卷 898-919页

作者： Michoski, C. Meyerson, D. Isaac, T. Waelbroeck, F. Univ Texas Austin Dept Aerosp Engn & Engn Mech Inst Computat Engn & Sci Austin TX 78712 USA Univ Texas Austin Dept Phys Inst Fus Studies Austin TX 78712 USA Univ Texas Austin Inst Computat Engn & Sci Austin TX 78712 USA

A new parallel discontinuous Galerkin solver, called ArcOn, is developed to describe the intermittent turbulent transport of filamentary blobs in the scrape-off layer (SOL) of fusion plasma. The model is comprised of an elliptic subsystem coupled to two convection-dominated reaction-diffusion-convection equations. Upwinding is used for a class of numerical fluxes developed to accommodate cross product driven convection, and the elliptic solver uses SIPG, NIPG, IIPG, Brezzi, and Bassi-Rebay fluxes to formulate the stiffness matrix. A novel entropy sensor is developed for this system, designed for a space-time varying artificial diffusion/viscosity regularization algorithm. Some numerical experiments are performed to show convergence order on manufactured solutions, regularization of blob/streamer dynamics in the SOL given unstable parameterizations, long-time stability of modon (or dipole drift vortex) solutions arising in simulations of drift-wave turbulence, and finally the formation of edge mode turbulence in the scrape-off layer under turbulent saturation conditions. Published by Elsevier Inc.

关键词： Nodal/modal Discontinuous Galerkin Unified Elliptic Hyperbolic Parabolic Plasma physics Fusion Tokamaks Verification blobs Modons Scrape-off layer Interior penalty Turbulent saturation Upwinding Artificial diffusion Massively parallel

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Observation of blobs and Holes in the Boundary Plasma of EAST Tokamak

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Plasma Science and Technology 2011年第4期13卷 410-414页

作者：颜宁徐国盛张炜常加峰王亮刘少承刘鹏汪惠乾蒋敏熊豪丁斯晔万宝年高翔 V.NAULIN A.H.NIELSEN J.JuulRASMUSSEN Institute of Plasma Physics Chinese Academy of Sciences Association Euratom-Risφ DTU

Intermittent convective transport at the edge and in the scrape-off layer （SOL） of EAST was investigated by using fast reciprocating Langmuir probe. Holes, as part of plasma structures, were detected for the first time inside the shear layer. The amplitude probability distribution function of the turbulence is strongly skewed, with positive skewed events （＂blobs＂） prevailing in the SOL region and negative skewed events （＂holes＂） dominant inside the shear layer. The statistical properties coincide with previous observations from JET. The generation mechanism of blobs and holes is also discussed. In addition burst structure and dynamics character of them are also presented.

关键词： intermittent transport blobs holes generation mechanism dynamics character

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Fast 2-D camera control, data acquisition, and database techniques for edge studies on NSTX

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FUSION ENGINEERING AND DESIGN 2014年第5期89卷 717-720页

作者： Davis, W. M. Ko, M. K. Maqueda, R. J. Roquemore, A. L. Scotti, F. Zweben, S. J. Princeton Plasma Phys Lab Princeton NJ 08543 USA Princeton HS Princeton NJ 08540 USA Nova Photon Princeton NJ 08543 USA

Fast 2-D cameras examine a variety of important aspects of the plasma edge and in-vessel components on the National Spherical Torus Experiment (NSTX). Four Phantom and two Miro visible-light cameras manufactured by Vision Research are used on NSTX for edge studies. Each camera can take several gigabytes (GBs) of data during each plasma pulse. Timely access to this amount of data can itself be a challenge, but analysing all these data using manual frame-by-frame examination is not practical. This paper describes image analysis, database techniques, and visualization methods used to organize the fast camera data and to facilitate physics insights from it. An example is presented of analysing and characterizing the size, movement and dynamics of coherent plasma structures (typically referred to as "blobs") near the plasma edge. Software tools that generate statistics of blob speed, shape, amplitude, size, and orientation are described. The characteristics of emitted blobs affect plasma confinement and heat loads on plasma facing components, and are thus of particular interest to future machines like ITER. (C) 2014 Elsevier B.V. All rights reserved.

关键词： Fast cameras NSTX blobs

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Fast 2-D camera control, data acquisition, and database techniques for edge studies on NSTX

Fast 2-D camera control, data acquisition, and database tech...

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9th IAEA Technical Meeting on Control, Data Acquisition and Remote Participation for Fusion Research

关键词： Fast cameras NSTX blobs

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Extended Kalman Filtering Based Multiple Object Tracking in Image Sequences

Extended Kalman Filtering Based Multiple Object Tracking in ...

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International Conference on Signal Propagation and Computer Technology (ICSPCT)

作者： Deori, Barga Thounaojam, Dalton Meitei Natl Inst Technol Comp Sci & Engn Silchar India

ISBN: (纸本)9781479931408

Multiple Object tracking in image sequences is an emerging topic of research. This paper consists of a robust object tracking algorithm for multiple object detection and tracking them in dynamic scenes. The algorithm consists of two important steps. Firstly, adaptive GMM based background modeling for foreground object segmentation. Secondly the tracking algorithm uses extended Kalman Filter to model the nonlinear dynamics and measurement models and uses data association problem to determine an appropriate association between objects and kalman filters. The association is necessary to track objects in multiple-object scenario. The experiment of our proposed algorithm shows good results for multiple object motion tracking in complex dynamic background.

关键词： Kalman filtering GMM LAP blobs Data Association Problem

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Recognition of Assamese Handwritten Numerals Using Mathematical Morphology

Recognition of Assamese Handwritten Numerals Using Mathemati...

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4th IEEE International Advance Computing Conference (IACC)

作者： Medhi, Kalyanbrat Kalita, Sanjib Kr Gauhati Univ Dept Comp Sci Gauhati India

ISBN: (纸本)9781479925711

The aim of this paper is to describe an algorithm to recognize Assamese handwritten numerals using mathematical morphology. The digits are classified into two groups. One group contains digits which contains one or more blobs or/and stems in its structure. The other group does not contain any blobs. The number of blobs is determined with the help of morphological boundary finding method considering the property as hole. We also use the concept called 'connected component' of morphology to recognize digits without blobs. Digits without blobs are extended to blobs by using connected component approach of morphology. Digits with blobs and stems need to recognize the number of stems. The present study shows that stems need not to be exactly vertical or horizontal to detect it. The proposed algorithm has been applied and tested for various handwritten digits from ISI Kolkata database. We also compare this algorithm for various printed Assamese digits. Experiment result shows that the average recognition rate that can be achieved by this algorithm is 80% for handwritten numerals and almost 100% for printed numerals. The result is obtained by using 50 handwritten samples for each digit and different printed Assamese digits.

关键词： Assamese Numeral recognition mathematical morphology handwritten numerals blobs stems

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Multi-Touch Helpdesk Management System with Communication Enable

Multi-Touch Helpdesk Management System with Communication En...

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International Conference on Communication Systems and Network Technologies

作者： Deeba Khanam Sunil Dhankhar Department of Computer Science and Engineering Swami Keshwanand Institute of Technology Jaipur Rajasthan India

ISBN: (纸本)9781479917983

The research in this paper focused on the development of a general purpose helpdesk system on a multi-touch panel for a collage or an institution. This system is implemented on Multi-touch technology under NUI (Natural User Interface). The developed helpdesk system would be able to help the guest and in-campus persons without any kind of special training, just by touching the surface or with usual hand gestures. Communication Feature makes the helpdesk communicable enable via both Wireless or network communication model and more powerful. The application would be implemented on a table-top surface which would support multi-touch technology. Making of such system in cost effective manner is the major task to be done. Dealing with hardware and software components and description of protocols used are illustrated in this document.

关键词： Touch blobs surface computing Helpdesk.NUI HCI GSM

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Experimental evaluation and basis function optimization of the spatially variant image-space PSF on the Ingenuity PET/MR scanner

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MEDICAL PHYSICS 2014年第6期41卷 062501页

作者： Kotasidis, Fotis A. Zaidi, Habib Univ Hosp Geneva Div Nucl Med & Mol Imaging CH-1211 Geneva Switzerland Univ Manchester MAHSC Wolfson Mol Imaging Ctr Manchester M20 3LJ Lancs England Univ Geneva Geneva Neurosci Ctr CH-1205 Geneva Switzerland Univ Groningen Univ Med Ctr Groningen Dept Nucl Med & Mol Imaging NL-9700 RB Groningen Netherlands

Purpose: The Ingenuity time-of-flight (TF) PET/MR is a recently developed hybrid scanner combining the molecular imaging capabilities of PET with the excellent soft tissue contrast of MRI. It is becoming common practice to characterize the system's point spread function (PSF) and understand its variation under spatial transformations to guide clinical studies and potentially use it within resolution recovery image reconstruction algorithms. Furthermore, due to the system's utilization of overlapping and spherical symmetric Kaiser-Bessel basis functions during image reconstruction, its image space PSF and reconstructed spatial resolution could be affected by the selection of the basis function parameters. Hence, a detailed investigation into the multidimensional basis function parameter space is needed to evaluate the impact of these parameters on spatial resolution. Methods: Using an array of 12 x 7 printed point sources, along with a custom made phantom, and with the MR magnet on, the system's spatially variant image-based PSF was characterized in detail. Moreover, basis function parameters were systematically varied during reconstruction (list-mode TF OSEM) to evaluate their impact on the reconstructed resolution and the image space PSF. Following the spatial resolution optimization, phantom, and clinical studies were subsequently reconstructed using representative basis function parameters. Results: Based on the analysis and under standard basis function parameters, the axial and tangential components of the PSF were found to be almost invariant under spatial transformations (similar to 4 mm) while the radial component varied modestly from 4 to 6.7 mm. Using a systematic investigation into the basis function parameter space, the spatial resolution was found to degrade for basis functions with a large radius and small shape parameter. However, it was found that optimizing the spatial resolution in the reconstructed PET images, while having a good basis function su

关键词： PET image reconstruction resolution recovery basis functions blobs

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