• Title, Summary, Keyword: Computational Grid

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Service Prediction-Based Job Scheduling Model for Computational Grid (계산 그리드를 위한 서비스 예측 기반의 작업 스케쥴링 모델)

  • Jang Sung-Ho;Lee Jong-Sik
    • Proceedings of the Korea Society for Simulation Conference
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    • pp.29-33
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    • 2005
  • Grid computing is widely applicable to various fields of industry including process control and manufacturing, military command and control, transportation management, and so on. In a viewpoint of application area, grid computing can be classified to three aspects that are computational grid, data grid and access grid. This paper focuses on computational grid which handles complex and large-scale computing problems. Computational grid is characterized by system dynamics which handles a variety of processors and jobs on continuous time. To solve problems of system complexity and reliability due to complex system dynamics, computational grid needs scheduling policies that allocate various jobs to proper processors and decide processing orders of allocated jobs. This paper proposes the service prediction-based job scheduling model and present its algorithm that is applicable for computational grid. The service prediction-based job scheduling model can minimize overall system execution time since the model predicts a processing time of each processing component and distributes a job to processing component with minimum processing time. This paper implements the job scheduling model on the DEVSJAVA modeling and simulation environment and simulates with a case study to evaluate its efficiency and reliability Empirical results, which are compared to the conventional scheduling policies such as the random scheduling and the round-robin scheduling, show the usefulness of service prediction-based job scheduling.

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Service Prediction-Based Job Scheduling Model for Computational Grid (계산 그리드를 위한 서비스 예측 기반의 작업 스케줄링 모델)

  • Jang Sung-Ho;Lee Jong-Sik
    • Journal of the Korea Society for Simulation
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    • v.14 no.3
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    • pp.91-100
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    • 2005
  • Grid computing is widely applicable to various fields of industry including process control and manufacturing, military command and control, transportation management, and so on. In a viewpoint of application area, grid computing can be classified to three aspects that are computational grid, data grid and access grid. This paper focuses on computational grid which handles complex and large-scale computing problems. Computational grid is characterized by system dynamics which handles a variety of processors and jobs on continuous time. To solve problems of system complexity and reliability due to complex system dynamics, computational grid needs scheduling policies that allocate various jobs to proper processors and decide processing orders of allocated jobs. This paper proposes a service prediction-based job scheduling model and present its scheduling algorithm that is applicable for computational grid. The service prediction-based job scheduling model can minimize overall system execution time since the model predicts the next processing time of each processing component and distributes a job to a processing component with minimum processing time. This paper implements the job scheduling model on the DEVS modeling and simulation environment and evaluates its efficiency and reliability. Empirical results, which are compared to conventional scheduling policies, show the usefulness of service prediction-based job scheduling.

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A STUDY ON THE NURBS GRID GENERATION AND GRID CONTROL (NURBS를 이용한 격자생성 및 제어기법)

  • Yoon, Yong-Hyun
    • Journal of computational fluids engineering
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    • v.12 no.3
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    • pp.20-28
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    • 2007
  • A fast and robust method of grid generation to multiple functions has been developed for flow analysis in three dimensional space. It is based on the Non-Uniform Rational B-Spline(NURBS) of an approximation method. Many of NURBS intrinsic properties are introduced and much more easily understood. The grid generation method, details of numerical implementation. examples of application, and potential extensions of the current method are illustrated in this paper. The object of this study is to develop the surface grid generation and the grid cluster techniques capable of resolving complex flows with shock waves, expansion waves, shear layers. The knot insert method of Non-Uniform Rational B-Spline seems well worked. In addition, NURBS has been widely utilized to generate grids in the computational fluid dynamics community. Computational examples associated with practical configurations have shown the utilization of the algorithm.

Computational Fluid Dynamics on The Grid Computing Environment (그리드 컴퓨팅 환경을 이용할 전산 유체 해석)

  • Sung Chun-ho;Cho Kum Won;Park Hyungwoo;Lee Sangsan;Kim Dae-Hee;Kwon Jang Hyuk
    • 한국전산유체공학회:학술대회논문집
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    • pp.71-77
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    • 2002
  • The grid technology is believed to be the next generation research tool for both computational and experimental scientists. With advanced network technologies and middleware, geographically distributed facilities can be tightly connected to provided a huge amount of resources or remote accessibility, In this paper, an overview of grid technology will be introduced with an emphasis in application to computational fluid dynamics. The computational fluid dynamics, which involves solution of partial differential equations, is basically limited by the computing power, With the grid technology, virtually unlimited resources are provided. The schematic structure of middleware and grid environment, as well as some preliminary results are presented.

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Multiblock Grid Generation for Turbomachinery Cascade-Flow Analysis (터보기계 익렬유동해석을 위한 다중블록 격자형성법)

  • Chung H. T.
    • Journal of computational fluids engineering
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    • v.1 no.1
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    • pp.19-25
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    • 1996
  • A multiblock grid generation has been developed to be reliably used for a Navier-Stokes simulation of the turbomachinery flow-fields A multiblock structure simplifies the creation of structured H-grids about complex turbomachinery geometries and facilitate the creation of a grid in the tip flow region. The numerical algorithm adopts the combination of the algebraic and elliptic method to create the internal grids efficiently and quickly. The grid refinement process is enhanced by developing strategies to utilized Bezier curves and splines along with weighted transfinite interpolation technique and by formulating the grid-imbedding method for the viscous boundary-layer meshes. For purposes of illustration, the grid generator is applied to the high turning turbine rotor blades. Two different types of computational grids are provided to be compared with respect to the grid adaptation to the flow simulations. Extension to three-dimensions was done to show the possibility of its application to the tip-flow simulations. The grid quality of the multiblock structure is good in the passages, with gloval orthogonality and adequate smoothness.

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UNSTRUCTURED MOVING-GRID FINITE-VOLUME METHOD FOR UNSTEADY SHOCKED FLOWS

  • Yamakawa M;Matsuno K
    • Journal of computational fluids engineering
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    • v.10 no.1
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    • pp.24-30
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    • 2005
  • Unstructured grid system is suitable for flows of complex geometries. For problems with moving boundary walls, the grid system must be time-dependently changing and deforming according to the movement of the boundaries when we use a body fitted grid system. In this paper, a new moving-grid finite-volume method on unstructured grid system is proposed and developed for unsteady compressible flows with shock waves. To assure geometric conservation laws on moving grid system, a control volume on the space-time unified domain is adopted for estimating numerical flux. The method is described and applied for two-dimensional flows.

An Integrated Toolset for Distributed Real-Time Systems Based on Computational Grid

  • Zhang, Lichen
    • Proceedings of the IEEK Conference
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    • pp.309-312
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    • 2002
  • Advances in networking infrastructure have led to the development of a new type of "computational grid" infrastructure that provides predictable, consistent and uniform access to geographically distributed resources such as computers, data repositories, scientific instruments, and advanced display devices Such Grid environments are being used to construct sophisticated, performance-sensitive applications in such areas as dynamic, distributed real-time applications. In this paper, we propose a toolset for designing distributed real-time systems based on computational grid. The toolset is based on a new methodology and integrates the models that methodology Proposed for designing real-time systems.

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DEVELOPMENT OF CFD PROGRAM BASED ON A UNSTRUCTURED POLYHEDRAL GRID AND ITS APPLICATION TO FLOW AROUND A OSCILLATING CIRCULAR CYLINDER (비정렬 다면체 격자계 기반 유동 해석 프로그램의 개발 및 진동하는 실린더 주변 유동에의 적용)

  • Lee, Sang-Hyuk;Kang, Seong-Won;Hur, Nahm-Keon
    • 한국전산유체공학회:학술대회논문집
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    • pp.483-487
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    • 2011
  • In the present study, a CFD program based on a finite volume method was developed by using an unstructured polyhedral grid system for the accurate simulation with the complex geometry of computational domain. To simulate the transient flow induced by the moving solid object, the program used a fractional step method and a ALE (Algebric Lagrangian-Eulerian) method. The grid deformation for the moving of solid object were performed with a spring analogy based on the center coordinate of each computational grid. To verify the present program with these methodologies, the numerical results of the flow around the fixed and oscillating circular cylinder were compared with the previous numerical results.

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AUTOMATIC GENERATION OF UNSTRUCTURED SURFACE GRID SYSTEM USING CAD SURFACE DATA (CAD 형상 데이터를 이용한 비정렬 표면 격자계의 자동 생성 기법)

  • Lee, B.J.;Kim, B.S.
    • Journal of computational fluids engineering
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    • v.12 no.4
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    • pp.68-73
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    • 2007
  • Computational Fluid Dynamics (CFD) approach is now playing an important role in the engineering process in these days. Generating proper grid system in time for the region of interest is prerequisite for the efficient numerical calculation of flow physics using CFD approach. Grid generation is, however, usually considered as a major obstacle for a routine and successful application of numerical approaches in the engineering process. CFD approach based on the unstructured grid system is gaining popularity due to its simplicity and efficiency for generating grid system compared to the structured grid approaches, especially for complex geometries. In this paper an automated triangular surface grid generation using CAD(Computer Aided Design) surface data is proposed. According to the present method, the CAD surface data imported in the STL(Stereo-lithography) format is processed to identify feature edges defining the topology and geometry of the surface shape first. When the feature edges are identified, node points along the edges are distributed. The initial fronts which connect those feature edge nodes are constructed and then they are advanced along the CAD surface data inward until the surface is fully covered by triangular surface grid cells using Advancing Front Method. It is found that this approach can be implemented in an automated way successfully saving man-hours and reducing human-errors in generating triangular surface grid system.

EFFECTS OF COMPUTATIONAL GRIDS ON NUMERICAL SIMULATION OF TRANSONIC TURBINE CASCADE FLOWFIELDS (천음속 터빈 익렬유동의 수치해석에서의 계산격자점 영향)

  • Chung H.T.;Jung H.N.
    • Journal of computational fluids engineering
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    • v.10 no.2
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    • pp.15-20
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    • 2005
  • Numerical investigations have been performed to examine the effects of the computational grids on the prediction of the flow characteristics inside the turbine cascades. Three kinds of grid system based on H-type grid are applied to the high-turning transonic turbine rotor blades and comparisons with the experimental data and the numerical results of each grid structure have been done. In addition, the grid sensitivity on the estimation of the blade performances has been investigated.