• 한국항공우주학회지
• /
• 제36권5호
• /
• pp.438-447
• /
• 2008

본 논문에서는 이동최소자승법을 이용한 근사모델을 사용하여 신뢰성 최적설계를 수행하였다. 신뢰성 최적설계의 수행을 위한 반응표면 생성에는 RSM 과 Kriging이 사용될 수 있다. RSM은 계산시간은 빠르나 비선형성이 강한 문제에 약하며 Kriging은 비선형성이 강한 문제에 적용할 수 있으나 계산시간이 오래 걸리는 단점이 있다. 이 두 방법을 보완한 방법인 이동최소자승법(MLSM)을 이용하여 신뢰성 최적설계를 위한 반응표면을 생성하였다. 이동최소자승법을 이용한 신뢰성 최적설계기법은 Rosenbrock function 과 six-hump carmel back function으로 검증하였고 다른 기법과 비교하였다. 이동최소자승법을 이용하여 무인항공기 배기 덕트의 신뢰성 최적설계를 수행하였고 이는 항공우주구조물의 최적설계에 유용할 것으로 보여 진다.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
• /
• pp.1356-1358
• /
• 2003

In the paper, a method making use of the characteristics of Dyad Green Function (DGF) and Fluctuation-Dissipation Theorem to get the brightness temperature of layered medium is introduced. Based on the approach and the measured data of multi-channel radiometer and Least Square Method (LSM), the thickness of lunar soil can be retrieved. These methods are significant to study on materials on lunar surface.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2002년도 춘계학술대회 논문집
• /
• pp.546-550
• /
• 2002

This paper proposes an error compensation method that improves accuracy with geometry information of injection molding parts. Geometric information can give an improved accuracy in reverse engineering. Measuring data can not lead to get accurate geometric model, including errors of physical parts and measuring machines. Measuring data include errors which can be classified into two types. One is molding error in product, the other is measuring error. Measuring error includes optical error of laser scanner, deformation by probe forces of CMM and machine error. It is important to compensate these in reverse engineering. Least square method(LSM) provides the cloud data with a geometry compensation, improving accuracy of geometry. Also, the functional shape of a part and design concept can be reconstructed by error compensation using geometry information.

• 한국지능시스템학회논문지
• /
• 제22권4호
• /
• pp.399-404
• /
• 2012

Evolutionary algorithms such as genetic algorithm (GA) have been proven their effectiveness when applying to the design of fuzzy models. However, it tends to suffer from computationally expensWive due to the slow convergence speed. In this study, we propose an approach to develop fuzzy models by means of an improved differential evolution (IDE) to overcome this limitation. The improved differential evolution (IDE) is realized by means of an orthogonal approach and differential evolution. With the invoking orthogonal method, the IDE can search the solution space more efficiently. In the design of fuzzy models, we concern two mechanisms, namely structure identification and parameter estimation. The structure identification is supported by the IDE and C-Means while the parameter estimation is realized via IDE and a standard least square error method. Experimental studies demonstrate that the proposed model leads to improved performance. The proposed model is also contrasted with the quality of some fuzzy models already reported in the literature.

• 한국정밀공학회지
• /
• 제15권7호
• /
• pp.167-174
• /
• 1998

This paper presents an unoccluded cylindrical object pose measurement using a slit beam laser in which a robot recognizes all of the unoccluded objects from the top of jumbled objects, and picks them up one by one. The elliptical equation parameters of a projected curve edge on a slice are calculated using LSM. The coefficients of standard elliptical equation are compared with these parameters to estimate the object pose. The hamming distances between the estimated coordinates and the calculated ones are extracted as measures to evaluate a local constraint and a smoothing surface curvature. The edges between slices are linked using error function based on the edge types and the hamming distances. The linked edges on slices are compared with the model object's length to recognize the unoccluded object. This proposed method may provide a solution to the automation of part handling in manufacturing environments such as punch press operation or part assembly.

• 한국결정성장학회지
• /
• 제23권4호
• /
• pp.173-179
• /
• 2013

다이아몬드는 원석의 형태가 불규칙하고 견고하더라도 보석으로 쉽게 가공될 수 있으며, 등급 평가에 영향력을 나타내는 테이블, 크라운, 퍼빌리언, 거들면을 정밀하게 측정하였다. Round Brilliant Cut Diamond의 표준 연마에 적합한 규격을 조사하였고, 통계적(95 %) 신뢰 구간으로 표준편차, 평균, 허용 오차를 검토하였다. 측정된 크기, 각도, 깊이, 두께의 변수들이 나타내는 분포에 따라, 커팅 등급의 빈도 분석과 프로포션을 비교하였다. 각 변수간의 상관관계와 프로포션에 나타난 영향력의 근거는 LSM(Least Square Method)을 적용한 회귀 분석으로 결정하였다. 본 논문에서, 다이아몬드의 테이블 크기와 퍼빌리언 깊이 퍼센트가 등급 결정에 많은 영향을 미치고, 특히, 퍼빌리언 깊이는 프로포션과 관련하는 주요 원인으로 광학 현상에도 작용함을 알 수 있었다.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2003년도 춘계학술대회 논문집
• /
• pp.1117-1122
• /
• 2003

The paper on table deflection by stop state and move speed at loaded load, and the table deflection measured of static load. It is developed program for Date correction of LSM(Least Square Method). We experimented the method as following. The first a Laser setting and scan Experimental device measured curvature radius, The second A center of measurement object and curvature radius taking of LSC.

• 한국정밀공학회지
• /
• 제27권10호
• /
• pp.52-60
• /
• 2010

It is generally important to get a precise position information for autonomous unmanned vehicle(AUV) to run safely. For getting the position of AUV, the GPS has been using to navigation in a vehicle. Though it is useful to finding a position, it is difficult to precisely control a trajectory of the AUV due to large measuring error which may reach over 10 meters. Therefore to apply AUV it needs to compensate for the error. This paper proposes a method to more precisely localize AUV using three low-cost differential global positioning systems (DGPS). The distance errors between each DGPS are minimized as using the least square method (LSM) and the Kalman filter to eliminate a Gaussian white noise. The selected DGPS is cheaper and easier to set up than the RTK-GPS. It is also more precise than the general GPS. The proposed method can compensate the relatively position error according to stationary and moving distance of the AUV. For evaluating the algorithm by simulation, the DGPS signal with the Gaussian white noise to any points is generated by the AR model and compared with the measurement signal. It is confirmed that the proposed method can effectively compensate the position error as comparing with the measurement signal. The compensated position signal can be used to localize and control the AUV in the road.

• 한국통신학회논문지
• /
• 제13권1호
• /
• pp.1-11
• /
• 1988

本 論文은 일정한 基準信號를 사용하는 基準모델 適應制御 시스템에 대한 可調節 파라미터의 有界性을 說明한다. 이 解析法은, Lyapunov函數의 또다른 性質로서 適應시스템의 安定度는 물론, 파라미터의 存在性, 有界性 및 有界領域을 밝힐 수 있다는 사실에 동기되었다. 2가지 適應則, 즉 一般的인 句配法(GGM) 및 最小自秉法(LSM)에 대하여, 여기서 提示된 새로운 方法에 의하여 파라미터 空間의 유일한 解集合을 확립할 수 있다. 파라미터 空間 解析法의 效率性을 證明하기 위한 電算機 시뮬레이션 結果도 역시 검토한다.

• Computers and Concrete
• /
• 제23권6호
• /
• pp.433-444
• /
• 2019

As rice husk ash (RHA) is not produced in controlled manufacturing process like cement, its properties vary significantly even within the same lot. In fact, properties of Rice Husk Ash Based Concrete (RHABC) are largely dictated by uncertainty leading to huge deviations from their expected values. This paper proposes a Robust Cost Optimization (RCO) procedure for RHABC, which minimizes such unwanted deviation due to uncertainty and provides guarantee of achieving desired strength and workability with least possible cost. The RCO simultaneously minimizes cost of RHABC production and its deviation considering feasibility of attaining desired strength and workability in presence of uncertainty. RHA related properties have been modeled as uncertain-but-bounded type as associated probability density function is not available. Metamodeling technique is adopted in this work for generating explicit expressions of constraint functions required for formulation of RCO. In doing so, the Moving Least Squares Method is explored in place of conventional Least Square Method (LSM) to ensure accuracy of the RCO. The efficiency by the proposed MLSM based RCO is validated by experimental studies. The error by the LSM and accuracy by the MLSM predictions are clearly envisaged from the test results. The experimental results show good agreement with the proposed MLSM based RCO predicted mix properties. The present RCO procedure yields RHABC mixes which is almost insensitive to uncertainty (i.e., robust solution) with nominal deviation from experimental mean values. At the same time, desired reliability of satisfying the constraints is achieved with marginal increment in cost.