• 전기학회논문지
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• 제68권1호
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• pp.83-89
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• 2019

In this paper, beam forming using moving least squares method (MLSM) is studied. In the previous research, the least squares method (LSM), one of the data interpolation methods, was used to determine the desired beam pattern and obtain a beam pattern that minimizes the square of the error with the desired beam pattern. However, LSM has a disadvantage in that the beam pattern can not be formed to satisfy the exact steering angle of the desired beam pattern and the peak sidelobe level (PSLL) condition. To overcome this drawback, MLSM is used for beam forming. In order to verify, the proposed method is applied in beam forming of Bezier platform array antenna which is one of conformal array antenna platform.

• 한국통신학회논문지
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• 제40권4호
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• pp.723-730
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• 2015

본 논문에서는 전시장에 사용되는 도슨트 로봇 (Docent Robot)의 자율주행 정밀도 향상을 위하여 최소자승법을 적용한 위치추적 보정 알고리즘 (Location tracking Compensation Algorithm based on Least-Squares Method, $LCA_{LSM}$)을 제안하고, 도슨트 로봇을 사용한 실험을 통하여 그 성능을 분석하였다. 제안한 $LCA_{LSM}$은 전시장에서 도슨트 로봇의 자율주행에서 엔코더/자이로 (encoder/gyro, E/G)에서 발생하는 누적오차를 줄이고 위치추적 정확도를 개선하기 위하여 수집된 로봇의 위치좌표를 최소자승법 (Least-Squares Method, LSM)에 적용하여 보정한다. 실험결과, 제안한 $LCA_{LSM}$의 위치추적 평균 오차 감소율은 시나리오 1 (S1) 및 시나리오 2 (S2)에서 $LCA_{KF}$(Location tracking Compensation Algorithm based on Kalman Filter, $LCA_{KF}$) 보다 4.85% 더 높음을 확인하였다. 또한, 제안한 $LCA_{LSM}$의 측정오차에 따른 표준 편차는 S1 및 S2에서 E/G와 $LCA_{KF}$에 비해 훨씬 낮을 뿐 아니라 균일함을 확인하였다. 따라서 제안한 $LCA_{LSM}$은 도슨트 로봇이 S1 및 S2의 직선 이동을 할 때 E/G 및 $LCA_{KF}$ 보다 더 안정적임을 알 수 있다.

• 한국전산구조공학회논문집
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• 제36권1호
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• pp.67-74
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• 2023

A meshless technique using the geometric conservation least-squares method (GC-LSM) was devised to discretize the governing equation of linear elasticity. Although the finite-element method is widely used for structural analysis, a meshless method was developed because of its advantages in a moving grid system. This work is the preliminary phase for developing a fully meshless-based fluid-structure interaction solver. In this study, Cauchy's momentum equation was discretized in strong form using GC-LSM for the structural domain, and the Newmark beta method was used for time integration. The solver was validated in 1D, 2D, and 3D benchmarking problems. Static and dynamic results were obtained. The results are more accurate than those of analytic solutions.

• 한국기계가공학회지
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• 제10권2호
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• pp.38-45
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• 2011

The criteria for determining the elements are the minimum zone method(MZM) and the least squares method(LSM). The LSM is deterministic and simple but is limited at the measurements whose errors are significant compared with form errors. For the precise condition, minimum zone method(MZM) has been selected to determine the elements. The roundness is the fundamental problem in the evaluating form errors. In this paper, anew approach adapting the genius education concept is proposed to obtain an accurate results for the MZM and the LSM of the roundness. Its computational algorithm is studied on a set of measured sample data. To be of almost no account of the specification(the number and the standard deviation etc.) of the sanple data, the results shoqs excellent reliability and high accuracy in estimating the roundness.

• Journal of Advanced Marine Engineering and Technology
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• 제31권1호
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• pp.58-66
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• 2007

Genetic Algorithms (GA) have some difficulties in practical applications because of too many function evaluations. To overcome these limitations, an approximated modeling method such as Response Surface Modeling(RSM) is coupled to GAs. Original RSM method predicts linear or convex problems well but it is not good for highly nonlinear problems cause of the average effect of the least square method(LSM). So the locally approximated methods. so called as moving least squares method(MLSM) have been used to reduce the error of LSM. In this study, the efficient evolutionary GAs tightly coupled with RSM with MLSM are constructed and then a 2-dimensional inviscid airfoil shape optimization is performed to show its efficiency.

• 한국전자파학회논문지
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• 제27권2호
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• pp.138-146
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• 2016

본 논문에서는 LSM(Least Squares Method)와 GA(Genetic Algorithm)를 이용한 광대역 컨포멀 배열 안테나의 최적 빔 형성을 제안하였다. LSM을 적용하여 컨포멀 배열 안테나의 빔 패턴을 선형 배열 안테나의 빔 패턴으로 근사시키는 가중치들을 구하였다. 그리고 GA를 이용하여 광대역에서 최적의 빔 패턴을 형성하는 컨포멀 배열 안테나의 최적 위치들을 구하였다. 제안된 방법을 검증하기 위해 Bezier 플랫폼 배열 안테나에 적용시켜 보았다.

• 한국정밀공학회지
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• 제16권8호
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• pp.130-137
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• 1999

The criteria for determining the elements are the minimum zone method(MZM) and the least squares method(LSM). The LSM is deterministic and simple but is limited at the measurements whose errors are significant compared with form errors. For the precise condition, minimum zone method(MZM) has been selected to determine the elements. It is not deterministic and nonlinear so that a optimizing procedure is needed. The Straightness is the fundamental problem in the evaluating form error. In this paper, a new approach adapting the genius education concept is proposed to obtain an accurate results for the minimum zone problem of the straightness. Its computational algorithm is studied on a set of randomly generated data. To be of almost no account of the specification(the number and the standard devistion etc.) of the sample data, the results shows excellent reliability and high accuracy in estimating the straightness.

• Wind and Structures
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• 제27권3호
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• pp.199-211
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• 2018

This paper deals with wind fragility and risk analysis of high rise buildings subjected to stochastic wind load. Conventionally, such problems are dealt in full Monte Carlo Simulation framework, which requires extensive computational time. Thus, to make the procedure computationally efficient, application of metamodelling technique in fragility analysis is explored in the present study. Since, accuracy by the conventional Least Squares Method (LSM) based metamodelling is often challenged, an efficient Moving Least Squares Method based adaptive metamodelling technique is proposed for wind fragility analysis. In doing so, artificial time history of wind load is generated by three wind field models: i.e., a simple one based on alongwind component of wind speed; a more detailed one considering coherence and wind directionality effect, and a third one considering nonstationary effect of mean wind. The results show that the proposed approach is more accurate than the conventional LSM based metamodelling approach when compared to full simulation approach as reference. At the same time, the proposed approach drastically reduces computational time in comparison to the full simulation approach. The results by the three wind field models are compared. The importance of non-linear structural analysis in fragility evaluation has been also demonstrated.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 2000년도 추계 학술발표회 논문집
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• pp.111-114
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• 2000

본 논문은 선형모델의 모델 계수의 결정방법으로 사용되는 최소자승법 (Least Squares Method, LSM)의 단점을 해결하기 위해 해석적으로 계산된 자료를 함께 적용하는 방법과 원자로의 출력분포 측정을 위한 SAM (Shape Annealing Matrix) 결정에 적용한 결과를 기술하고 있다. 해석적 자료를 함께 적용할 경우 연료 연소에 따른 원자로 특성변화를 적절히 반영하여 LSM 추정치의 정확도를 크게 개선할 수 있음을 확인하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1882-1887
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• 2003

The response surface method (RSM) became one of famous meta modeling techniques, however its approximation errors give designers several restrictions. Classical RSM uses the least squares method (LSM) to find the best fitting approximation models from the all given data. This paper discusses how to construct RSM efficiently and accurately using moving least squares method (MLSM) with sensitivity information. In this method, several parameters should be determined during the construction of RSM. Parametric study and optimization for these parameters are performed. Several difficulties during approximation processes are described and numerical examples are demonstrated to verify the efficiency of this method.