• Journal of applied mathematics & informatics
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• 제8권3호
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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.

• Structural Engineering and Mechanics
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• 제90권5호
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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.

• 대한수학회보
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• 제37권3호
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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.

• Tribology and Lubricants
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• 제14권4호
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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.

• Journal of information and communication convergence engineering
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• 제4권4호
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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.

• 농촌계획
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• 제19권3호
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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.

• Geomechanics and Engineering
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• 제12권4호
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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.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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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.

• 터널과지하공간
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• 제29권1호
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• pp.64-74
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• 2019

지하공동의 굴착 과정에서 암반 절리로 인해 생성되는 암석블록의 거동 여부는 지하공동의 역학적 안정성에 있어서 중요한 요소이다. 본 연구에서는 대심도 지하공동 조건 하에서 지체응력 및 절리물성 조건에 따른 암석블록의 거동 안정성을 정량적으로 분석하였다. 이론적으로 계산된 암석블록의 거동조건과 3DEC 수치해석을 통해 분석된 암석블록의 거동양상을 비교하여, 이론값과 수치해석 결과간의 오차를 지체응력 및 절리물성 조건에 따라 분석하였다. 암석블록의 거동 안정성 분석을 수행한 결과는 수치해석 결과와 비교할 때 약 5% 이하의 오차를 보여 본 연구에서 제시한 이론적 방법론의 적용가능성을 검증하였다.

• 한국통신학회논문지
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• 제17권10호
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• pp.1109-1116
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• 1992

Mathematical morphology는 이론적 배경으로 신호 및 시스템의 기하학적 특성을 해석하는데 우수하고 잡음이 섞인 데이터를 고르기에 있어서 매우 성공적으로 적용되고 있다. 본 논문에서는 morphological필터의 하드웨어 구현은 같은 회로에서 gray scale dilation과 erosion을 수행하여 최소값과 최대값을 선택하도록 함으로써 회로의 복잡성을 줄이고 병렬처리가 가능하도록 하였다. Morphological filter의 구조는 structuring element블록, 이미지 데이타 블록, 제어 블록, ADD 블록, MIN/MAX블록으로 구성되고 실시간 처리가 가능하도록 하드웨어를 설계, one chip화 한다.