• Title/Summary/Keyword: Theoretical block

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A VARIANT OF BLOCK INCOMPLETE FACTORIZATION PRECONDITIONERS FOR A SYMMETRIC H-MATRIX

  • Yun, Jae-Heon;Kim, Sang-Wook
    • Journal of applied mathematics & informatics
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    • v.8 no.3
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    • pp.705-720
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    • 2001
  • We propose a variant of parallel block incomplete factorization preconditioners for a symmetric block-tridiagonal H-matrix. Theoretical properties of these block preconditioners are compared with those of block incomplete factoriztion preconditioners for the corresponding somparison matrix. Numerical results of the preconditioned CG(PCG) method using these block preconditioners are compared with those of PCG using other types of block incomplete factorization preconditioners. Lastly, parallel computations of the block incomplete factorization preconditioners are carried out on the Cray C90.

Theoretical analysis of stress-strain behavior of multi-layer RC beams under flexure

  • Ertekin Oztekin
    • Structural Engineering and Mechanics
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    • v.90 no.5
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    • pp.505-515
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    • 2024
  • In this study, obtaining theoretical stress-strain curves and determining the parameters defining the equivalent rectangular stress block were aimed for 3 and 4-layered rectangular Reinforced Concrete (RC) cross-sections subjected to flexure. For these aims, the analytical stress-strain model proposed by Hognestad was chosen for the concrete grades (20 MPa≤fck≤60 MPa) used in this study. The tensile strength of the concrete was neglected and the thickness of the concrete layers in the compression zone of the concrete cross-section was taken as equal. In addition, while concrete strength was kept constant within each layer, concrete strengths belonging to separate layers were increased from the neutral axis towards the outer face of the compression zone of the concrete cross-section. After the equivalent rectangular stress block parameters were determined by numerical iterations, variations of these parameters depending on concrete strength in layers and layer numbers were obtained. Finally, some analytical equations have been proposed to predict the equivalent stress block parameters for the 3 and 4-layered RC cross-sections and validities of these proposed equations were shown by different metrics in this study.

BLOCK INCOMPLETE FACTORIZATION PRECONDITIONERS FOR A SYMMETRIC H-MATRIX

  • Yun, Jae-Heon;Kim, Sang-Wook
    • Bulletin of the Korean Mathematical Society
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    • v.37 no.3
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    • pp.551-568
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    • 2000
  • We propose new parallelizable block incomplete factorization preconditioners for a symmetric block-tridiagonal H-matrix. Theoretical properties of these block preconditioners are compared with those of block incomplete factorization preconditioners for the corresponding comparison matrix. Numerical results of the preconditioned CG(PCG) method using these block preconditioners are compared with those of PCG method using a standard incomplete factorization preconditioner to see the effectiveness of the block incomplete factorization preconditioners.

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A Study on the Driving of Rods in Hydraulic Bent-axis-type Axial Piston Pump Part 1: The Theoretical Analysis of Driving Mechanism (유압 사축식 액셜 피스톤 펌프의 로드 구동에 관한 연구 제1보: 구동 메카니즘의 이론해석)

  • 김종기;오석형;정재연
    • Tribology and Lubricants
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    • v.14 no.4
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    • pp.51-57
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    • 1998
  • Recently, bent-axis-type axial piston pumps driven by rods being in extensively used in the world, because of simple design, lightweight, effective cost. So, to guarantee the quality of bent-axis-type axial piston pumps driven by rods, it is necessary to know characteristics of the driving mechanism of rods. But, as they perform both reciprocating and spinning motions, it is difficult to understand driving mechanism. In this paper, I studied the theoretical driving mechanisms of cylinder block driven by rods through geometric method. I found that the cylinder block was driven by one rod in limited area and the driving area was changed by rod's tilting angle and cylinder block's swivel angle.

Performance Evaluation of Block Error of FS MC-CDMA System in Various Nakagami Fading Channels

  • Jin, Ze-Guang;Kang, Heau-Jo
    • Journal of information and communication convergence engineering
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    • v.4 no.4
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    • pp.131-135
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    • 2006
  • In this paper, we discusses that the theoretical analysis is made for the performance of FS MC-CDMA by the aid of the Nakagami fading channels and the block error probabilities of the FS MC-CDMA in Nakagami fading channel are presented. The channel fading speed, slow or fast, is considered in evaluating block error probabilities. The effectiveness of diversity combining in improving block error performance is examined.

Introduction of the Block Grant in Agriculture, Forestry, and Fishery Sectors (지방농정 자율성 확대를 위한 농림수산 포괄보조금제 운용 방안)

  • Cho, Jae-Whan;Lee, Han-Sung
    • Journal of Korean Society of Rural Planning
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    • v.19 no.3
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    • pp.145-155
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    • 2013
  • This study proposed the introduction of the block grant in agriculture, forestry, and fishery sectors so that the local governments get greater autonomy in agricultural policy. First of all, theoretical background on block grant was reviewed and present situation in Korea regarding block grant was examined. Four criteria were set to evaluate the eligibility for the block grant. Four criteria imply that block grant is more appropriate with small-scaled similar projects, high locality projects, easily evaluated projects, and easily formula-applied projects. Applying these criteria to the projects subsidized by the national government, appropriate projects as the block grant were selected. Finally, specific operation scheme of the block grant was proposed.

Pullout resistance of concrete anchor block embedded in cohesionless soil

  • Khan, Abdul J.;Mostofa, Golam;Jadid, Rowshon
    • Geomechanics and Engineering
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    • v.12 no.4
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    • pp.675-688
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    • 2017
  • The anchor block is a specially designed concrete member intended to withstand pullout or thrust forces from backfill material of an internally stabilized anchored earth retaining wall by passive resistance of soil in front of the block. This study presents small-scale laboratory experimental works to investigate the pullout capacity of a concrete anchor block embedded in air dry sand and located at different distances from yielding boundary wall. The experimental setup consists of a large tank made of fiberglass sheets and steel framing system. A series of tests was carried out in the tank to investigate the load-displacement behavior of anchor block. Experimental results are then compared with the theoretical approaches suggested by different researchers and codes. The appropriate placement of an anchor block and the passive resistance coefficient, which is multiplied by the passive resistance in front of the anchor block to obtain the pullout capacity of the anchor, were also studied.

Distribution of the Equivalent Rectangular Stress Block for High-Strength Polymer Concrete Beams (고강도 폴리머 콘크리트보의 등가직사각형 응력분포)

  • 김관호;연규석;김남길;조규우
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.05a
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    • pp.915-920
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    • 2001
  • This study was conducted to analysis the distribution of the rectangular stress block for high-strength polymer concrete beam. C-shaped specimens were produced and tested to compute parameters of the rectangular stress block. They were $\kappa_{1}$ = 0.73, $\kappa_{3}$ = 0.94 and $\gamma$= 0.845, respectively. Experimental value of flexural strength of beam was same to be compared with theoretical value. But there is desirable to need many experimental data in order to exact design of polymer concrete structure.

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Fast Analysis of Rock Block Behavior on Underground Opening considering Geostatic Stress Conditions (지체응력조건을 고려한 지하공동 주변부 암석블록의 신속한 거동 안정성 분석)

  • Kang, Il-Seok;Song, Jae-Joon
    • Tunnel and Underground Space
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    • v.29 no.1
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    • pp.64-74
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    • 2019
  • Behavior of a rock block consisting of rock joints during excavation of an underground opening is an important factor for the mechanical stability of the opening. In this study, the behavior of a rock block under different geostatic stress and joint property conditions was analyzed quantitatively. The behavior of the rock block analyzed by 3DEC numerical analysis was compared with that of the theoretical calculation, and the error between the theoretical value and the numerical analysis result was analyzed under various geostatic stress and joint property conditions. The result of the stability analysis of a rock block showed less than 5% of error with numerical simulation result, which verified the applicability of the purposed analytic solution.

Design of Morphological Filter for Image Processing (영상처리용 Morphological Filter의 하드웨어 설계)

  • 문성용;김종교
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.17 no.10
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    • pp.1109-1116
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    • 1992
  • Mathematical morphology, theoretical foundation for morphological filter, is very efficient for the analysis of the geometrical characteristics of signals and systems and is used as a predominant tool for smoothing the data with noise. In this study, H/W design of morphological filter is implemented to process the gray scale dilation and the erosion in the same circuit and to choose the maximum and minimum value by a selector, resulting in their education of the complexity of the circuit and an architecture for parallel processing. The structure of morphological filter consists of the structuring-element block, the image data block, the control block, the ADD block, the MIN/MAX block, etc, and is designed on an one-chip for real time operation.

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