• 제목/요약/키워드: Good lattice points

검색결과 8건 처리시간 0.023초

격자기반(Lattice-based) 라틴 하이퍼큐브(Latin hypercube) 계획의 제안

  • 황현식;박정수
    • 한국통계학회:학술대회논문집
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    • 한국통계학회 2001년도 추계학술발표회 논문집
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    • pp.115-120
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    • 2001
  • 라틴 하이퍼큐브 실험계획은 전산실험을 위하여 Mckay, Beckman과 Conover(1979)에 의해 고안된 방법으로 실험을 한번 시행하는데 많은 시간과 비용이 들거나 인자가 많은 실험에 효율적으로 사용할 수 있다. 하지만 이 실험계획 역시 실험영역 전체에서 골고루 배치되지 않을 가능성이 있으므로 이를 보완하려는 시도가 이루어져 왔으며, 여기서는 good lattice points(glp)와 계통추출을 응용하여 격자기반(lattice-based) Lhd의 두 가지 방법을 제안하였다. 모의실험 결과 glp 실험계획을 응용한 "방법 1"은 모형을 가정한 엔트로피에 기초한 최적 기준으로 검토한 경우 우수하였다. "방법 2"는 표본조사에 널리 쓰이는 계통추출을 응용하였으며 입력변수가 각기 다른 9개의 실험함수에 관하여 표본 평균의 추정치와 분산, MSE를 비교한 결과, 다른 실험계획들보다 우수하였다. 이 결과는 실험점이 실험영역 전체에서 골고루 퍼져서 나타난 것으로 보이며, 향후 전산실험계획에서의 응용을 기대할 수 있다.

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프로펠러 특성의 이론적 산정법에 관한 연구 (A Study on the Theoretical Calculation of Screw Propeller Open-Water Characteristics)

  • 송강섭
    • 한국항해학회지
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    • 제14권3호
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    • pp.15-33
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    • 1990
  • In recent years, propellers with various blade configurations such as highly skewed propellers are often fitted to ships from the viewpoint of reduction of vibration and noise. In the design of such propellers, design charts based on methodical series tests are to be complemented by theoretical calculations for accurate estimation of propeller open-water characteristics. The author intended to develop a method to estimate propeller open-water characteristics based on Quasi -Vortex - Lattice Method originally developed by Lan for solving planar thin wings, The Quasi - Vortex - Lattice Method has the simplicity and flexibility of Vortex - Lattice Method. Its accuracy is comparable to that of the Vortex - Lattice Method. Converged solution can be obtained with a small number of control points and further, leading edge suction force can be calculated directly. In the present paper, a numerical method to estimate propeller open-water characteristics based on the Quasi - Vortex - Lattice Method is reviewed and its application to marine propellers is described in detail. Comparison of propeller open-water characteristics obtained by the present method with experimental data showed good agreement for a wide variety of propellers including highly skewed propellers.

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다중 안테나를 갖는 공간 다중화 시스템을 위한 maximum likelihood 검출기의 성능 분석 (Performance analysis of maximum likelihood detection for the spatial multiplexing system with multiple antennas)

  • 신명철;송영석;권동승;서정태;이충용
    • 대한전자공학회논문지TC
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    • 제42권12호
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    • pp.103-110
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    • 2005
  • 본 논문에서는 다중안테나를 갖는 공간 다중화 시스템에서 주어진 채널에 대한 maximum likelihood 검출기의 성능을 수식적으로 유도하였다. 벡터 심볼 오차율을 구하기 위해 nearest neighbor의 방향을 나타내는 에러벡터를 정의하였다. 전송 벡터 심볼이 랜덤한 채널에 의해 변환 될 경우 확정적으로 4개의 nearest neighbor를 가짐을 정의된 에러벡터의 특성을 이용해 입증하였다 변형된 구 검출기로부터 획득 가능한 에러벡터와 최소거리 정보를 바탕으로 주어진 랜덤 채널 하에서 벡터 심볼 오차율을 수식적으로 도출하였다. 유도된 벡터 심볼 오차식을 검증하기 위해, 랜덤 채널을 unitary 채널, dense 채널, sparse 채널로 분류한 후 각 채널 상황에서 유도된 결과 식을 모의 실험 결과와 비교하였다. 모의실험 결과로부터 유도된 벡터 심볼 오차식이 다양한 랜덤 MIMO 채널에서 ML 검출기의 성능을 잘 근사하고 있음을 입증하였다.

Look-Up Table 기반의 복잡도가 낮은 Lattice Reduction MIMO 검출기 (Low-Complexity Lattice Reduction Aided MIMO Detectors Using Look-Up Table)

  • 이충원;이호경;허서원
    • 대한전자공학회논문지TC
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    • 제46권5호
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    • pp.88-94
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    • 2009
  • 본 논문에서는 다중 안테나 시스템에서 신호 수신을 위한 lattice reduction (LR) 기반 복호기의 복잡도를 줄이기 위한 방법을 제안한다. ML (Maximum Likelihood) 방식이 복호 성능은 우수하지만 안테나와 성상 점의 개수에 따라 지수적으로 복잡도가 증가하는데 반해 LR 기반의 복호기는 상대적으로 적은 복잡도로 동일한 다이버시티 성능을 보이는 것으로 알려져 있다. 그러나 LR 과정도 채널 행렬의 열 벡터 교환 과정을 포함한 반복 연산에 의해서 복잡도가 높고 하드웨어 구현이 어려운 점이 있다. LR 과정은 채널 행렬이 주어지는 경우 유일하게 결정되기 때문에 이 과정을 offline으로 미리 수행하여 Look-Up Table(LUT)에 저장하는 방식으로 계산량을 줄일 수 있다. 본 논문에서는 LR 기반 수신기에서 LUT 를 효율적으로 구성하는 방법을 제시하고 성능을 비교한다. 제안된 방식을 적용할 경우 기존의 LR 방식에 비하여 적은 연산량으로 유사한 수신 성능을 보임을 모의실험을 통하여 보인다.

液體金屬의 常態和 (A Partition Function for Liquid Metals)

  • 김완규
    • 대한화학회지
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    • 제6권1호
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    • pp.36-46
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    • 1962
  • 筆者는 週期表 1族에 適用되는 液體金屬의 模型으로서 純粹한 液體金屬은 2原子分子의 單振動子로 構成되면 이 振動子는 自己가 古有하는 싸이트(site)種에 따라 두가지 에너지狀態中 하나를 取하게 된다고 假想함으로써 液體狀態和를 誘導하였다. 이 狀態和食은 本質的으로는 하나의 物質固有의 常數(${\Theta}$)를 內包하고 있으며 液體金屬에 대하여 이 特性値를 줌으로써 여러가지 熱力學的 性質 즉 蒸氣壓, 液體의 엔트로리, 比熱 等을 算出하여 實測値와 比較하여 보았다. 그 結果는 滿足스러운 一致를 보여준다.

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단면 분할 FFD를 이용한 3D 라스트 데이터 생성시스템 개발 (Three Dimensional Last Data Generation System Utilizing Cross Sectional Free Form Deformation)

  • 김시경;박인덕
    • 제어로봇시스템학회논문지
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    • 제11권9호
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    • pp.768-773
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    • 2005
  • A new approach for human foot modelling and last design based on the cross sectional method is presented in this paper. The proposed last design method utilizes the dynamic trimmed parametric patches for the foot 3D data and last 3D data. The cross section a surface of 3D foot for the 3D last, design modeling of free form geometric last shapes. The proposed last design scheme wraps the 3D last data surrounding the measured 3D foot data with the effect of deforming the last design rule The last design rule of the FFD is constructed on the FFD lattice based on foot-last shape analysis. In addition, the control points of FFD lattice are constructed with cross sectional data interpolation methods from the a finite set of 3D foot data. The deformed 3D last result obtained from the proposed FFD is saved as a 3D dxf foot data. The experimental results demonstrate that the last designed with the proposed scheme has good performance.

A Statistical Termodynamic Study of Phase Equilibria in Microemulsions

  • Kyung-Sup Yoo;Hyungsuk Park
    • Bulletin of the Korean Chemical Society
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    • 제12권3호
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    • pp.334-342
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    • 1991
  • To investigate the phase equilibria and structural properties of microemulsions, we study a simple phenomenological model on the basis of the cubic lattice cell with which the oil- and water-filled cells are connected one another, respectively. The surfactant is assumed to be insoluble in both oil and water, and to be adsorbed at the oil-water interface. The Schulman condition, according to which the lateral pressure of the surfactant layer is compensated by the oil-water interfacial tension, is found to hold to good approximation in the middle-phase microemulsion. Our results show that the oil- and water-filled domains in that microemulsion are about 50-150 $\AA$ across, and depend sensitively on the curvature parameters. The phase diagram is not symmetric in this model. It may be asymmetrized intrinsically by non-equivalency of oil and water. The two- and tree-phase equilibria including critical points and critical endpoints are found.

'그리드'(Grid)의 형성과 해체 -서양회화의 사적맥락과 그 해석을 중심으로 - (A Study on the Construction and Deconstruction of the 'Grid' : The Historical Context and Interpretation)

  • 김재관
    • 조형예술학연구
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    • 제1권
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    • pp.125-164
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    • 1999
  • The Grid, a lattice structure adapted in paintings, is one of thesimplest plastic structures based on the intersection of horizontal and perpendicular lines. Though mankind has, from the pre-history to the present day, put it to good use in everyday life as a traditional practice or a magical, esoteric, religious emblem in the case of the teciform of primitve art, it was in the paintings of Piet Mondrian that the Grid showed its modern, artistic transformation. As we suggest in the title, before I state the Grid as a plastic construction of modern painting, this dissertation inquires the Grid structure that extends over paintings through the ages as a painterly conept, especially focused on their formation and deconstruction. To begin with, my dissertation investigates, as a historical background, a general idea of the geometrical structure and phases of its transition in art, prior to dealing with the Grids as plastic strures in modern painting. the core of my study on formal Grids is permeated through the third chapter. The first chapter concentrates on, firstly, difining the notion of the Grid and geometrical structure, secondly, searching for a historical backgrounb with whict the so- called modern Grid-paintings come in, inquiring into the formation of the illusion-Grid as aresult of discovering the linear perpective and the situation of the conflict and reconciliaton between reality and illusion. Based on these considerations, the second cecond chapter will examine the various sitations of formation and adaptation of the paintery Grids in the Literalism-Grid, as we have already seen in the chapter one. And the cardinal third chapter devotes itself to the process of the formation of the so-called Object-Grid and Literal-Grid in the Literalism or Minimalism as its logical extension of the Painterly Grid. With it we can get to an interpretation and understanding of the meaning and qualites of Grid dwelt in Modernism thst transformed the structure of Painterly Grid originally as a plane concept to the third dimentionl structure. And then, the fourth chapter, we try to draw a new meaning andre-interpretation of the Formal-Grid as a representatuinnal structure appeared in the post-modernist paintings, going with its deconstructional situation. Therefore, we can, in our study on Grids, see the various points of view in the interpretation of them as illusion-structure, as plane-structure, and as cubic-structure; its concept differs form times, oscillating between its formation and deconstruction. The Grid, as we have seen in my dissertation, contains various problems and significations in art that deserve to investigate throughly, including some important plastic problem such as space and plane, and, in the case of do-grid, time. We may expect new concepts of it that will have difference meanings. 1 hope my study makes some contributions to understanding the coordination of the abstruse modern and contemporary art.

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