• Title/Summary/Keyword: Computational efficiencies

Search Result 81, Processing Time 0.029 seconds

Development of Efficient Moving Memory Column Solver for Large Finite Element Analysis (대형 유한요소 해석을 위한 골조구조물의 최종강도해석에 관한 연구)

  • 이성우;이동근;송윤환
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 1990.10a
    • /
    • pp.34-39
    • /
    • 1990
  • For the analysis of structures, specifically if it is large-scale, in which case it can not be solved within the core memory, the majority of computation time is consumed In the solution of simultaneous linear equation. In this study an efficient in- and out-of-core column solver for sparse symmetric matrix utilizing memory moving scheme is developed. Compare with existing blocking methods the algorithm is simple, therefore the coding and computational efficiencies are greatly enhanced. Upon available memory size, the solver automatically performs solution within the core or outside core. Analysis example shows that the proposed method efficiently solve the large structural problem on the small-memory microcomputer.

  • PDF

TWO-SAMPLE COMPARISON USING SIGN TEST ON RANKED-SET SAMPLES

  • Kim, Dong-Hee;Kim, Young-Cheol
    • Journal of applied mathematics & informatics
    • /
    • v.5 no.1
    • /
    • pp.263-268
    • /
    • 1998
  • This paper proposes the two-sample comparison us-ing sign test based on ranked-set sample(RSS). We investigate the asymptotic properties of the proposed test statistic and compare the asymptotic relative efficiencies of the proposed test statistic with re-spect to Mann-Whitney-Wilcoxon test statistic based on RSS and Mann-Whitney-Wilcoxon test statistic based on the simple random sample(SRS).

Time Dependent Analysis Considering the Construction Sequences in Bridges of Movable Scaffolding System (MSS) (시공단계를 고려한 MSS 공법 교량의 시간의존적 거동해석)

  • Kwak Hyo-Gyoung;Son Je-Kuk
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 2005.04a
    • /
    • pp.167-174
    • /
    • 2005
  • Through time-dependent analyses of RC bridges constructed by a movable scaffolding system (MSS) considering the construction sequence and creep deformation of concrete, structural responses related to the member forces are reviewed. On the basis of the compatibility condition and equilibrium equation at every construction stage, basic equations that can describe the moment variation with time in movable scaffolding construction are derived. By using the introduced relations, the design moment and its variation over time can easily be obtained with only the elastic analysis results and without additional time-dependent analyses considering the construction sequences. In addition, the design moments determined by the introduced equations are compared with the results from a rigorous numerical analysis with the objective of establishing the relative efficiencies of the introduced equations.

  • PDF

A Study on Open BIM based Building Energy Evaluation based on Quantitative Factors

  • Kim, In-han;Jin, Jin;Choi, Jung-Sik
    • Korean Journal of Computational Design and Engineering
    • /
    • v.15 no.4
    • /
    • pp.289-296
    • /
    • 2010
  • Energy consumption by buildings accounts for a large part of the world‘s energy consumption. Methods to analyze building energy consumption before construction have been studied for decades. With BIM (Building Information Modeling) technology, architects can easily export building information to data models in order to analyze the design‘s effect on building energy efficiency. Although several BIM-based energy simulation applications are currently available, utilizing these applications for energy efficiency simulation is difficult. In this paper, by comparing existing BIM-based energy applications, the authors test the building energy efficiencies estimated by some BIM models, offer ideas and solutions to problems that appeared during the test process and propose new methods for BIM-based energy evaluation based on quantitative factors.

NUMERICAL ANALYSIS OF THREE-DIMENSIONAL FLOW IN A MIXED-FLOW PUMP (사류펌프 내 삼차원 유동의 수치해석)

  • Ahn, H.J.;Kim, J.H.;Kim, K.Y.
    • 한국전산유체공학회:학술대회논문집
    • /
    • 2009.04a
    • /
    • pp.223-226
    • /
    • 2009
  • This paper presents three-dimensional flow analysis for a mixed-flow pump which consists of a rotor and a stator. Reynolds-averaged Navier-Stokes equations with shear stress transport turbulence model are discretized by finite volume approximations and solved by the commercial CFD code CFX 11.0. Structured grid system is constructed in the computational domain, which has O-type grids near the blade surfaces and H-type grids in other regions. Validation of the numerical results was performed with experimental data for head coefficients and hydraulic efficiencies at different flow coefficients. This paper shows that the pump characteristics can be predicted effectively by numerical analysis.

  • PDF

A Robustness of Hierarchic Element Formulated by Integral s of Legendre Polynomial (적분형 르장드르 함수에 의한 계층요소의 통용성)

  • 우광성
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 1991.10a
    • /
    • pp.75-80
    • /
    • 1991
  • The purpose of this study is to ascertain the robustness of p-version model with hierarchic intergrals of Legendre shape functions in various applications including plane stress/strain, axisymmetric and shell problems. The most important symptoms of accuracy failure in modern finite elements are spurious mechanisms and a phenomenon known as locking which are exhibited for incompressible materials and irregular shapes which contain aspect ratios(R/t, a/b), tapered ratio(d/b), and skewness. The condition numbers and energy norms are used to estimate numerical errors, convergence characteristics and algorithmic efficiencies for verifying the aforementioned symptoms of accuracy failure. Numerical results from p-version models are compared wi th those from NASTRAN, SAP90, and Cheung's hybrid elements.

  • PDF

IMAGE RESTORATION BY THE GLOBAL CONJUGATE GRADIENT LEAST SQUARES METHOD

  • Oh, Seyoung;Kwon, Sunjoo;Yun, Jae Heon
    • Journal of applied mathematics & informatics
    • /
    • v.31 no.3_4
    • /
    • pp.353-363
    • /
    • 2013
  • A variant of the global conjugate gradient method for solving general linear systems with multiple right-hand sides is proposed. This method is called as the global conjugate gradient linear least squares (Gl-CGLS) method since it is based on the conjugate gradient least squares method(CGLS). We present how this method can be implemented for the image deblurring problems with Neumann boundary conditions. Numerical experiments are tested on some blurred images for the purpose of comparing the computational efficiencies of Gl-CGLS with CGLS and Gl-LSQR. The results show that Gl-CGLS method is numerically more efficient than others for the ill-posed problems.

Shape Design Optimization of High-Speed Air Vehicles Using Non-Uniform Rational B-Splines (NURBS 곡선을 이용한 고속비행체 최적형상설계)

  • Kim Sang-Jin;Lee Jae-Woo;Byun Yung-Hwan;Kim Myung-Seong
    • 한국전산유체공학회:학술대회논문집
    • /
    • 2001.05a
    • /
    • pp.72-77
    • /
    • 2001
  • The computational efficiency of an shape optimization procedure is highly dependent upon the proper selection of shape representation methods and design variables. In this study, shape functions, Bezier and NURBS(non-uniform rational B-splines) curves are selected as configuration generation methods and their efficiencies on the nose shape design of high-speed air vehicles, are compared. The effects of the number of control points, weighting factors and the optimization methods when utilizing the NURBS curves, are investigated. By implementing Bezier and NURBS curves, shapes having lower drag than the optimization case utilizing the shape functions, were obtained, hence it was demonstrated that these curves have better capability in representing the configuration. Efforts will be given to improve the convergence behavior when utilizing the NURBS, hence to reduce the number of Navier-Stokes analysis calculations.

  • PDF

Flexural Characteristics of the Overlayed RC Beam Strengthened with Rebars, CFRP, and Steel Plate.

  • 오홍섭;심종성;이차돈;최완철;신영수;홍기섭;홍영균
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 1996.10a
    • /
    • pp.221-229
    • /
    • 1996
  • An analytical method based on the nonlinear layered finite element method is used to simulate the load-deflection behavior of strengthened beam. Beams considered in this study are the ones strengthened either with external steel plate or Carbon Fiber Reinforced Plastic (CFRP) sheets bonded to the overlay soffit or with reinforcing rebars in the overlay. The theoretically obtained load-deflections and strains of the strengthened beam are compared to the corresponding experimental values. Comparing the approximate measures on the cumulative slips, efficiencies of the repairing techniques are evaluated. Parametric studies are, then, peformed using the developed model to investigate the effects of design variables on the overal flexural behavior of the strengthened beam. Simply supported beams under monotonically increasing symmetrical loads are considered exclusively.

  • PDF

A STUDY ON THE EFFICIENCY OF AERODYNAMIC DESIGN OPTIMIZATION IN DISTRIBUTED COMPUTING ENVIRONMENT (분산컴퓨팅 환경에서 공력 설계최적화의 효율성 연구)

  • Kim Y.J.;Jung H.J.;Kim T.S.;Son C.H.;Joh C.Y.
    • Journal of computational fluids engineering
    • /
    • v.11 no.2 s.33
    • /
    • pp.19-24
    • /
    • 2006
  • A research to evaluate the efficiency of design optimization was carried out for aerodynamic design optimization problem in distributed computing environment. The aerodynamic analyses which take most of computational work during design optimization were divided into several jobs and allocated to associated PC clients through network. This is not a parallel process based on domain decomposition in a single analysis rather than a simultaneous distributed-analyses using network-distributed computers. GBOM(gradient-based optimization method), SAO(Sequential Approximate Optimization) and RSM(Response Surface Method) were implemented to perform design optimization of transonic airfoils and evaluate their efficiencies. dimensional minimization followed by direction search involved in the GBOM was found an obstacle against improving efficiency of the design process in the present distributed computing system. The SAO was found fairly suitable for the distributed computing environment even it has a handicap of local search. The RSM is apparently the most efficient algorithm in the present distributed computing environment, but additional trial and error works needed to enhance the reliability of the approximation model deteriorate its efficiency from the practical point of view.