• Title/Summary/Keyword: simplified solution

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Linear Analysis of Water Surface Waves Generated by Submerged Wave Board Whose Upper and Lower Ends Oscillate Horizontally Freely (상하단이 자유롭게 수평동요하는 수중 조파판에 의해 생성된 수면파의 근사해석)

  • Kim, Hyochul;Oh, Jungkeun;Kwon, Jongoh;Lew, Jae-Moon
    • Journal of the Society of Naval Architects of Korea
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    • v.56 no.5
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    • pp.418-426
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    • 2019
  • To derive a simplified analytic solution which can be utilized as a fundamental solution for the wave maker design, a segment of the wave board has been idealized as a submerged line segment in a two dimensional domain of a wave flume. The lower end of the line segment could be located at arbitrary depth of the wave flume and the upper end of the board could be also submerged to any depth from the free surface. The freely oscillating motion of the wave board is assumed to be defined by determining the condition of horizontal oscillation on both ends differently. The submerged wave board oscillating in horizontal direction could be specified by selecting the amplitude, frequency and the phase lag differently on lower and upper ends of the board. The simplified two dimensional wave generated by the wave board segment has been obtained by the first order perturbation method. It is found that the general solution of the freely oscillating wave board in two dimensional domain could be decomposed into the solution of flap motion with lower end hinge and swing motion with upper end hinge. The case study of the analytic solutions has been carried out to evaluate the effect on the wave height due to the difference of oscillation frequency, phase difference and variation of stroke between for the motion of both ends. It is found that the solution of the freely oscillating wave board could be utilized for the development of high performance wavemaker especially for irregular waves.

Simplified Analysis of Rectangular Liquid Storage Tanks Considering Fluid-Structure Interaction (유체-구조물 상호작용을 고려한 직사각형 액체저장탱크의 단순해석법)

  • Lee, Jin Ho;Cho, Jeong-Rae
    • Journal of the Earthquake Engineering Society of Korea
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    • v.26 no.5
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    • pp.203-209
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    • 2022
  • A simplified method for earthquake response analysis of a rectangular liquid storage tank is proposed with fluid-structure interaction considered. In order to simplify the complex three-dimensional structural behavior of a rectangular liquid storage tank, it is assumed that structural deformation does not occur in the plane parallel to the direction in which the earthquake ground motion is applied but in the plane perpendicular to the direction. The structural deformation is approximated by combining the natural modes of the simple beam and the cantilever beam. The hydrodynamic pressure, the structure's mass and stiffness, and the hydrodynamic pressure's added mass are derived by applying the Rayleigh-Ritz method. The natural frequency, structural deformation, pressure, effective mode mass, and effective mode height of the rectangular liquid storage tank are obtained. The structural displacement, hydrodynamic pressure, base shear, and overturning moment are calculated. The seismic response analysis of an example rectangular liquid storage tank is performed using the proposed simplified approach, and its accuracy is verified by comparing the results with the reference solution by the finite element method. Existing seismic design codes based on the hydrodynamic pressure in rigid liquid storage tanks are observed to produce results with significant errors that cannot be ignored.

Simplified Analytic Solution of Submerged Wave Board Motion and Its Application on the Design of Wave Generator (조파판 수중운동의 근사해석과 조파기 설계에 응용)

  • Kwon, Jongoh;Kim, Hyochul;Lew, Jae-Moon;Oh, Jungkeun
    • Journal of the Society of Naval Architects of Korea
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    • v.54 no.6
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    • pp.461-469
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    • 2017
  • A segment of the wave board has been expressed as a submerged line segment in the two dimensional wave flume. The lower end of the line segment could be extended to the bottom of the wave flume and the other opposite upper end of the board could be extended to the free surface. It is assumed that the motion of the wave board could be defined by the sinusoidal motion in horizontal direction on either end of the wave board. When the amplitude of sinusoidal motion of the wave board on lower and upper end are equal, the wave board motion could express the horizontally oscillating submerged segment of piston type wave generator. The submerged segment of flap type wave generator also could be expressed by taking the motion amplitude differently for the either end of the board. The pivot point of the segment motion could play a role of hinge point of the flap type wave generator. Simplified analytic solution of oscillating submerged wave board segment in water of finite depth has been derived through the first order perturbation method at two dimensional domain. The case study of the analytic solution has been carried out and it is found out that the solution could be utilized for the design of wave generator with arbitrary shape by linear superposition.

A MODIFIED SOLUTION PROCEDURE FOR THE ELLIPTIC-TYPE CONDITIONAL MOMENT CLOSURE MODEL IN NONPREMIXED TURBULENT REACTING FLOW

  • Liu, Tao;Huh, Kang-Yul
    • 한국연소학회:학술대회논문집
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    • 1997.06a
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    • pp.113-122
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    • 1997
  • The conditional moment closure formulation considering the molecular and turbulent diffusion is derived. A simplified solution procedure is proposed to reduce the computational burden due to the increased dimensionality of the conditionally averaged variables. A conditionally averaged variable is expressed as a linear weighted average of the two extremes, 'no reaction' and 'equilibrium' states. The modified elliptic-type conditional moment closure formulation is implemented to simulate a two dimensional nonpremixed mixing layer reacting flow. Results show good agreement for the conditional averages of the species concentration in Bilger et al.

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A LOCAL APPROXIMATION METHOD FOR THE SOLUTION OF K-POSITIVE DEFINITE OPERATOR EQUATIONS

  • Chidume, C.E.;Aneke, S.J.
    • Bulletin of the Korean Mathematical Society
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    • v.40 no.4
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    • pp.603-611
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    • 2003
  • In this paper we extend the definition of K-positive definite operators from linear to Frechet differentiable operators. Under this setting, we derive from the inverse function theorem a local existence and approximation results corresponding to those of Theorems land 2 of the authors [8], in an arbitrary real Banach space. Furthermore, an asymptotically K-positive definite operator is introduced and a simplified iteration sequence which converges to the unique solution of an asymptotically K-positive definite operator equation is constructed.

Approximate Solution for Finding the Buckling Strength of Orthotropic Rectangular Plates (직교이방성판의 좌굴강도를 구하기 위한 근사식의 개발)

  • J. H. Jung;S. J. Yoon;S. K. You
    • Composites Research
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    • v.16 no.5
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    • pp.28-38
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    • 2003
  • In this study, the analytical investigation of orthotropic rectangular plate is presented. The loaded edges are assumed to be simply supported and the unloaded edges could have elastically restrained boundary conditions including the extreme boundary condition such as simple, fixed, and free. Using the closed-form solutions, the buckling analyses of orthotropic plate with arbitrary boundary conditions are performed. Based on the data obtained by conducting numerical analysis, the simplified form of equation for finding the buckling coefficient of plate with elastically restrained boundary conditions at the unloaded edges is suggested as a function of aspect ratio, elastic restraint. and material properties of the plate. The results of buckling analyses by closed-form solution and simplified form of solution are compared for various orthotropic material properties. It is confirmed that the difference of results is less than 1.5%.

Model-based subpixed motion estimation for image sequence compression (도영상 압축을 위한 모델 기반 부화소 단위 움직임 추정 기법)

  • 서정욱;정제창
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.35S no.1
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    • pp.130-140
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    • 1998
  • This paper presents a method to estimate subpixel accuracy motion vectors using a mathermatical model withoug interpolation. the proposed method decides the coefficients of mathematical model, which represents the motion vector which is achieved by full search. And then the proposed method estimates subpixel accuracy motion vector from achieved mathematical model. Step by step mathematical models such as type 1, type 2, type 3, modified bype 2, modified type 3, and Partial Interpolation type 3 are presented. In type 1, quadratic polynomial, which has 9 unknown coefficients and models the 3by 3 pixel plane, is used to get the subpixel accuracy motion vectors by inverse matrix solution. In type 2 and 3, each quadratic polynomial which is simplified from type 1 has 5 and 6 unknown coefficients and is used by least square solution. Modified type 2 and modified type 3 are enhanced models by weighting only 5 pixels out of 9. P.I. type 3 is more accurate method by partial interpolation around subpixel which isachieved by type 3. LThese simulation results show that the more delicate model has the better performance and modified models which are simplified have excellent performance with reduced computational complexity.

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Study on the Leaching Characteristics of Simulated Nuclear Waste Glass with variable Composition (핵폐기용 모의글라스의 조성변화에 따른 용출특성에 관한 연구)

  • 한호현;이승한;류수착;류봉기
    • Journal of the Korean institute of surface engineering
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    • v.28 no.5
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    • pp.259-266
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    • 1995
  • In order to manufacture an attractive waste glass for the permanent and secure disposal of high-level radioactive waste, the complex composition of the simulated nuclear waste glass PNL-7668 was simplified to a composition of sodium borosilicate glass. The substitutions of $Fe_2O_3$ and $Al_2O_3$ were added to examine on the leaching characteristics of simulated nuclear waste glass with variable composition. The leach tests for these glasses were performed according to 'MCC-1, Static Leach Test Procedure' in acid and basic solution. In this study, for the $Al_2O_3$-containing glasses, Na ion release from these glasses was higher in acid solution than in basic solution. As the content of $Fe_2O_3$ was increased in glasses, Na ion release was increased in acid solution, in spite of decrease of amount of total mass diminution.

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Inverse Kinematics of a Serial Manipulator : Redundancy and a Closed-rom Solution by Exploting Geomertiric Constraints (원료불출기의 역기구학 : 여유자유도와 구속조건을 이용한 닫힌 형태의 해)

  • 홍금식;김영민;최진태;신기태;염영일
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1996.04a
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    • pp.661-665
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    • 1996
  • An inverse kinemetics problem of a reclaimer which digs and transports ironstones or coals in the raw yard is investigated. Because of the special features of the reclaimer of which scooping buckets are attached around the rotating drum at the end of boom, kinematic redundancy occurs in determining the joint varialbes For a given reclaiming point in space the forward kinematics yields 3 equations, however the number of involved variables in the equations are four. A plane equation approximating the surface near a reclaiming point is obtained by considering 8 adjacent points surrounding the reclaiming point. One extra equation to overcome redunduncyis further obtained from the condition that the normal vector at a reclaiming point is perpendicular to the plane. An approximate solution for a simplified problem is first discussed, Numerical solution for the oritinal nonlinear porblem with a constraint equation is also investigated. Finally a closed form solution which is not exact but sufficiently close enough is proposed by exploiting geometric constraint.

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New Material Architecture and Its Process Integration for a-Si TFT Array Manufacturing

  • Song, Jean-Ho;Park, Hong-Sick;Kim, Sang-Gab;Cho, Hong-Je;Jeong, Chang-Oh;Kang, Sung-Chul;Kim, Chi-Woo;Chung, Kyu-Ha
    • 한국정보디스플레이학회:학술대회논문집
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    • 2002.08a
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    • pp.552-555
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    • 2002
  • In order to achieve higher performance and low cost a-Si TFT-LCD panel, new material architecture and its process integration for a-Si TFT array manufacturing method were developed. Material combination of low resistant dry-etchable metal and new pixel electrode under currently adopted 4 mask process made it possible to get more-simplified manufacturing method and better device performance for the a-Si TFT-LCD application. Proposed 4 mask process architecture with optimized wet etchants and dry etching process was applicable to various devices such as notebook, monitor and TV.

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