• 전기학회논문지
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• 제56권12호
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• pp.2265-2267
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• 2007

The purpose of this work is to compare the local fitting and global fitting approaches while applying regression model to the PTT-BP data for the prediction of exercise blood pressures. We used linear and nonlinear regression models to represent the PTT-BP relationship during exercise. PTT-BP data were acquired both under resting state and also after cycling exercise with several load conditions. PTT was calculated as the time between R-peak of ECG and the peak of differential photo-plethysmogram. For the identification of the regression models, we used local fitting which used only the resting state data and global fitting which used the whole region of data including exercise BP. The results showed that the global fitting was superior to the local fitting in terms of the coefficient of determination and the RMS (root mean square) error between the experimental and estimated BP. The nonlinear regression model which used global fitting showed slightly better performance than the linear one (no significant difference). We confirmed that the wide-range of data is required for the regression model to appropriately predict the exercise BP.

• 대한기계학회논문집A
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• 제30권10호
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• pp.1219-1226
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• 2006

The ASTM test standard recommends the use of the compact tension specimen for creep crack growth rates measurement. In the creep crack growth rate test, the displacement rate due to creep is obtained by subtracting the contribution of elastic and plastic components from the total load line displacement rate based on displacement partitioning method fur determining $C^*-integral$, which involves Ramberg-Osgood (R-O) fitting procedures. This paper investigates the effect of the R-O fitting procedures on plastic displacement rate estimates in creep crack growth testing, via detailed two-dimensional and three-dimensional finite element analyses of the standard compact tension specimen. Four different R-O fitting procedures are considered; (i) fitting the entire true stress-strain data up to the ultimate tensile strength, (ii) fitting the true stress-strain data from 0.1% strain to 0.8 of the true ultimate strain, (iii) fitting the true stress-strain data only up to 5% strain, and (iv) fitting the engineering stress-strain data. It is found that the last two procedures provide reasonably accurate plastic displacement rates and thus should be recommended in creep crack growth testing. Moreover, several advantages of fitting the engineering stress-strain data over fitting the true stress-strain data only up to 5% strain are discussed.

• 한국정보통신학회논문지
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• 제23권4호
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• pp.388-393
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• 2019

외란(Outlier)이 있는 데이터를 피팅(Fitting)하는 방법으로 RANSAC(RANdom SAmple Consensus)알고리즘이 선, 원, 타원 등 의 피팅에 많이 사용되고 있다. 본 논문은 다수의 평면에 대한 3차원 포인트 데이터가 주어질 때 각 평면에 대해 RANSAC기반 평면 피팅을 최근 딥러닝 등에 많이 사용되는 GPU의 하나인 CUDA를 이용하여 효율적으로 수행하는 알고리즘을 제안한다. 모의 데이터와 실제 데이터를 이용하여 제안된 알고리즘의 성능을 CPU와 비교하여 보인다. 외란이 많고 인라이어(inlier) 비율이 낮을수록 CPU대비 속도가 향상되고 평면의 개수가 많을수록 평면당 데이터개수가 많을수록 병렬처리에 의한 속도가 가속됨을 보인다. 제안된 방법은 다중 평면 피팅외의 다른 피팅에도 쉽게 적용할 수 있다.

• 한국CDE학회논문집
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• 제9권3호
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• pp.183-191
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• 2004

This paper deals with smooth curve fitting of data corrupt by noise. Most research efforts have been concentrated on employing the smoothness penalty function with the estimation of its optimal parameter in order to avoid the 'overfilling and underfitting' dilemma in noisy data fitting problems. Our approach, called DBSF(Differentiation-Based Smooth Fitting), is different from the above-mentioned method. The main idea is that optimal functions approximately estimating the derivative of noisy curve data are generated first using genetic programming, and then their integral values are evaluated and used to recover the original curve form. To show the effectiveness of this approach, DBSP is demonstrated by presenting two illustrative examples and the application of estimating the principal dimensions of bulk cargo ships in the conceptual design stage.

• 한국전기전자재료학회논문지
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• 제35권3호
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• pp.223-231
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• 2022

분광학은 재료의 결정학적, 화학적 구조를 분석하기 위해 가장 보편적으로 활용되는 분석 기법이다. 이러한 기조에 따라 다양한 분석 소프트웨어와 peak fitting과 관련된 기술적 가이드라인이 보급되었지만, 정작 '왜' 중간 계산 과정을 거치고 해당 함수를 쓰는지에 대한 논의는 부족한 실정이다. 따라서 본 tutorial에서는 X선 기반 분광광도계를 통해 얻은 데이터 분석의 기초를 논하고자 한다. 이를 위해 관련된 peak fitting을 위해 필요한 실용적 배경지식을 제시하였다. 나아가, 하나의 예시로 임의로 선정한 X선 광전자 분광법 데이터에 대한 curve fitting 과정을 순서에 따라 알기 쉽게 소개하였다. 제시한 기초 이론은 특정 소프트웨어에 국한된 내용이 아니라 fitting tool이 있는 모든 소프트웨어에서 그대로 활용 가능할뿐더러 다른 분광법 데이터를 분석하는 데 적용 가능하기 때문에, 본 내용을 숙지한다면 보다 수월한 연구 진행을 위한 바탕이 될 수 있을 것이라 기대한다.

• 한국국방경영분석학회지
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• 제25권2호
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• pp.158-169
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• 1999

This paper is concerned with the application of generalized linear interactive modelling(GLIM) to the binary categorical data. To analyze the categorical data given by a contingency table, finding a good-fitting loglinear model is commonly adopted. In the case of a contingency table with a response variable, we can fit a logit model to find a good-fitting loglinear model. For a given $2^4$ contingency table with a binary response variable, we show the process of fitting a loglinear model by fitting a logit model using GLIM and SAS and then we estimate parameters to interpret the nature of associations implied by the model.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 1998년도 가을 학술발표논문집 Vol.25 No.2 (2)
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• pp.479-481
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• 1998

Noise가 있는 data에서 shape나 parameter를 찾았을 때 일반적으로 Hough transform이나 regression을 적용한다. Hough transform은 parameter space의 차수가 커지면 memory 문제가 존재하며, regression 모델은 한 개의 변수를 다른 변수의 함수로 가정하여 error를 최소화하여 데이터중 1 set의 parameter만 존재한다는 가정을 하여야 하는 문제점이 있다. 본 논문에서는 이러한 두 방법의 단점들을 보완하며, Fuzzy개념을 도입한 data fitting 방법을 제안하였다. 이 문제는 genetic algorithm을 도입하여 data를 Fuzzy membership을 갖는 것으로 가정한 최적화 문제로 해결하였다. 직선과 평면에 대한 실험 결과를 보인다.

• 제어로봇시스템학회논문지
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• 제17권8호
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• pp.768-776
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• 2011

This paper considers a data fitting problem for rational function models using the LM (Levenberg-Marquardt) optimization method. Rational function models have various merits on representing a wide range of shapes and modeling complicated structures by polynomials of low degrees in both the numerator and denominator. However, rational functions are nonlinear in the parameter vector, thereby requiring nonlinear optimization methods to solve the fitting problem. In this paper, we propose a data fitting method for rational function models based on the LM algorithm which is renowned as an effective nonlinear optimization technique. Simulations show that the fitting results are robust against the measurement noises and uncertainties. The effectiveness of the proposed method is further demonstrated by the real application to a 3D depth camera calibration problem.

• 한국의류학회지
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• 제30권5호
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• pp.722-732
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• 2006

The pattern making of the tight-fitting collars which often used in diving suits, dance wear, or cycle wear has not been fully established. To develop tight-fitting collar pattern directly from 3D images from the representative somatotypes, dressforms developed by Jaeun Jung were used. The 3D scan data of the four male dressforms were obtained using Exyma-1200. Triangle Simplification and the Runge-Kutta method were applied to reduce the 3D scan data points and to make the segmented triangular patches in a plane from 3D data. As results, apparent differences between the tight-fitting collar patterns obtained from the 3D scan data and the ordinary 2D collar patterns were found around the center back line. The curvatures of the center back line were higher in all types of the tight-fitting collar than in the ordinary collar pattern. Relative differences in the shape of collar lines among four representative Korean men were reported. To fit the curved shape of the back neckline, 1.8 cm should be reduced from the upper neckline in average. We suggested the direct pattern making method for the 2D tight-fitting collar patterns considering the 3D shape of various types of men's dressform.

• 대한수학회논문집
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• 제17권1호
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• pp.121-142
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• 2002

We are interested in the curve fitting problems in such a way that the sum of the squares of the orthogonal distances to the given data points is minimized. Especially, the fitting an ellipse to the given data points is a problem that arises in many application areas, e.g. computer graphics, coordinate metrology, etc. In [1] the problem of fitting ellipses was considered and numerically solved with general purpose methods. In this paper we present another new ellipse fitting algorithm. Our algorithm if mainly based on the steepest descent procedure with the view of ensuring the convergence of the corresponding quadratic function Q(u) to a local minimum. Numerical examples are given.