• Journal of Electrical Engineering and Technology
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• 제7권4호
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• pp.606-614
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• 2012

A practical recursive linear robust estimation scheme is proposed for target localization in the sensor network which provides range difference of arrival (RDOA) measurements. In order to radically solve the known practical difficulties such as sensitivity for initial guess and heavy computational burden caused by intrinsic nonlinearity of the RDOA based target localization problem, an uncertain linear measurement model is newly derived. In the suggested problem setting, the target localization performance of the conventional linear estimation schemes might be severely degraded under the low SNR condition and be affected by the target position in the sensor network. This motivates us to devise a new sensor network localization algorithm within the framework of the recently developed robust least squares estimation theory. Provided that the statistical information regarding RDOA measurements are available, the estimate of the proposition method shows the convergence in probability to the true target position. Through the computer simulations, the omnidirectional target localization performance and consistency of the proposed algorithm are compared to those of the existing ones. It is shown that the proposed method is more reliable than the total least squares method and the linear correction least squares method.

• International Journal of Aeronautical and Space Sciences
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• 제14권1호
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• pp.85-90
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• 2013

This paper presents a study on terrain referenced navigation (TRN). The extended Kalman filter (EKF) is adopted as a filter method. A Jacobian matrix of measurement equations in the EKF consists of terrain slope terms, and accurate slope estimation is essential to keep filter stability. Two slope estimation methods are proposed in this study. Both methods are based on the least-squares approach. One is planar regression searching the best plane, in the least-squares sense, representing the terrain map over the region, determined by position error covariance. It is shown that the method could provide a more accurate solution than the previously developed linear regression approach, which uses lines rather than a plane in the least-squares measure. The other proposed method is weighted planar regression. Additional weights formed by Gaussian pdf are multiplied in the planar regression, to reflect the actual pdf of the position estimate of EKF. Monte Carlo simulations are conducted, to compare the performance between the previous and two proposed methods, by analyzing the filter properties of divergence probability and convergence speed. It is expected that one of the slope estimation methods could be implemented, after determining which of the filter properties is more significant at each mission.

• 응용통계연구
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• 제29권7호
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• pp.1155-1163
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• 2016

본 논문은 혼합효과의 선형모형에서 분산성분들의 추정방법으로 사영을 다루고 있다. 상수적합법에서 이용되는 제곱합에서의 감소(reductions in sums of squares) 대신에 사영을 이용하여 구하는 방법을 제시하고 있다. 단계별 방법에 의한 잔차모형으로부터 각 분산성분의 추정과 관련된 사영행렬을 구성하는 방법을 제공하고 있다. 사영행렬로 표현되는 이차형식의 기댓값을 이용하여 선형방정식계를 구성하고 적률법으로 분산성분을 추정하게 된다. 고정효과는 가중최소제곱법으로 추정되고 분산성분의 신뢰구간추정에 Satterthwaite의 근사과정으로 자유도를 계산하는 방법을 설명하고 있다.

• 조명전기설비학회논문지
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• 제21권7호
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• pp.61-67
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• 2007

전력수요예측은 전력계통의 운용을 위해 필수적이다. 따라서 다양한 방법이 제시되어 왔으며, 특히 특수일의 수요예측은 평일과 구분되며, 부하 패턴을 축출하기에 충분한 자료 확보가 어려워 예측 오차가 크게 나타난다. 본 논문에서는 특수일의 부하예측 정확도를 개선하기 위해 퍼지 최소자승 선형회귀 모델을 분석한다. 4종류의 퍼지 최소자승 선형회귀 모델에 대해 분석과 사례연구를 통하여 가장 정확한 모델을 제시한다.

• 한국해양공학회지
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• 제24권1호
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• pp.20-33
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• 2010

The paper deals with strength design of a riser support installed on floating production storage and offloading (FPSO) vessel under various loading conditions - operation, extreme, damaged, one line failure case (OLFC) and installation. The design problem is formulated such that thickness sizing variables are determined by minimizing the weight of a riser support structure subject to stresses constraints. The initial design model is generated based on an actual FPSO riser support specification. The finite element analysis (FEA) is conducted using MSC/NASTRAN, and optimal solutions are obtained via moving least squares method (MLSM) in the context of response surface based approximate optimization. For the meta-modeling of inequality constraint functions of stresses, a constraint-feasible moving least squares method (CF-MLSM) is used in the present study. The method of CF-MLSM, compared to a conventional MLSM, has been shown to ensure the constraint feasibility in a case where the approximate optimization process is employed. The optimization results present improved design performances under various riser operating conditions.

• 대한수학교육학회지:수학교육학연구
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• 제13권1호
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• pp.57-75
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• 2003

The goal of this paper is to offer material which make mathematising Fruedenthal(1991) proposed be experienced through the process of teaching and learning mathematics. In this paper, the number of unit squares a diagonal passes through for an m$\times$n lattice rectangle is studied and its generalization is discussed. Through this discussion, the adaptability of this material Is analysed. Especially, beyond inductional conjecture, the number of unit squares is studied by more complete way, and generalization in 3-dimension and 4-dimension are tried. In school mathematics, it is enough to generalize in 3-dimension. This material is basically appropriate for teaching and learning mathematising in math classroom. In studying the number of unit squares and unit cubes, some kinds of mathematising are accompanied. Enough time are allowed for students to study unit squares and unit cubes to make them experience mathematising really. To do so, it is desirable to give students that problem as a task, and make them challenge that problem for enough long time by their own ways. This material can be connected to advanced mathematics naturally in that it is possible to generalize this problem in n-dimension. So, it is appropriate for making in-service mathematics teachers realize them as a real material connecting school mathematics and advanced mathematics.

• 한국실내디자인학회논문집
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• 제25권4호
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• pp.3-12
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• 2016

The purpose of this study was to analyze City squares in Europe according to Biophilic Design elements to apply domestic Indoor Squares in Mixed-use building for relaxation. This study seeks to present a direction for designing an indoor square that uses the aspects of European city square. The following details consist the purpose of the study. First, Perspective from the Biophilic design and analyzing criteria of Europe city square. Second, European city square is analyzed to establish the criteria to be applied to indoor square. Third, based on European city square analysis, the planning direction for domestic indoor square is suggested. This result of paper proceeds as follows. First, it describes the analysis of the Indoor Squares of the domestic Mixed-use building. The results were derived of the fact that not applying the water elements and Facade greening. Second, In Europe Square, It is accounted for the highest proportion (33%) of the spaciousness. Third, Through a comparative analysis domestic indoor square was derived that the higher the need to improve the spaciousness and botanical motif. It is the ultimate goal of this study based on the analysis of the city square to set the criteria for the biophilic design of the indoor square to present the orientation of the indoor square.

• 한국음향학회지
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• 제15권4호
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• pp.93-97
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• 1996

완전최소자승법(total least squares method, TLS) Ax${\simeq}$b와 같은 형태의 시스템 식을 푸는데 있어 데이터 행렬 A와 b에 잡음비 섞인 경우에 편이 되지 않은 해를 구하기 위하여 널리 이용된다. 그러나 임펄수성의 잡음과 같은 heavy tailed 확률분포를 갖는 잡음이 존재할 때 완전 최소자승법은 unbiased estimator이지만 최소자승법(least squares, LS)과 마찬가지로 경인하지 못한 성능을 보인다. 본 논문에서는 TLS 방법의 견인성에 대하여 논하고 완전최소자승법의 해의 특성을 기반으로 하여 견인한 완전최소자승법(robust TLS, ROTLS)을 제안한다. 또한 ROTLS 방법을 시스템식별문제에 적용하여 그 성능을 평가한다.

• Journal of applied mathematics & informatics
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• 제27권1_2호
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• pp.1-12
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• 2009

Iterative algorithms are proposed for the least-squares symmetric solution of AXB = E with a submatrix constraint. We characterize the linear mappings from their independent element space to the constrained solution sets, study their properties and use these properties to propose two matrix iterative algorithms that can find the minimum and quasi-minimum norm solution based on the classical LSQR algorithm for solving the unconstrained LS problem. Numerical results are provided that show the efficiency of the proposed methods.

• Communications for Statistical Applications and Methods
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• 제15권6호
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• pp.799-813
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• 2008

This paper deals with the properties of the fuzzy least squares estimators for fuzzy linear regression model. Especially fuzzy triangular input-output model including error term is proposed. The error term is considered as a fuzzy random variable. The asymptotic unbiasedness and the consistency of the estimators are proved using a suitable metric.