• 조명전기설비학회논문지
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• 제25권5호
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• pp.73-78
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• 2011

We developed a noise reduction algorithm for the measurement accuracy improvement of a fiber-optic distributed temperaure sensor system. The denoising technique is based on the wavelet transform. The proposed algorithm was applied to a FBG sensor output with the Gaussian line-fitting algorithm to minimize the output noise which originated from the intensity noise of the laser light source and the instability of signal porcessing. We confirmed the feasibility of the denoising algorithm by comparing the measurement results with those obtained with the Gaussian line-fitting algorithm only.

• 소성∙가공
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• 제18권8호
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• pp.607-616
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• 2009

There are three sub-processes associated with the assembly of the valve seat and cylinder head; heat fitting, cold fitting, and shrink fitting. In the heat fitting stage, the cylinder head is heated to a specified temperature and then squeezed toward the outer diameter of the valve seat. The cold fitting process cools the valve seat and safely squeezes it toward the inner diameter of cylinder head. However, these methods increased the installations & running cost and curtailed productivity. To address these problems, we analyzed the shrink fitting process using the contact pressure caused by fitting interference between the outer diameter of the valve seat and the inner diameter of the cylinder head. In this study, a closed form equation for predicting the contact pressure and fitting load is proposed. For quality control of the assembly line, principal factors of the shrink fitting process influenced in contact pressure were simulated by the FEM. Actual loads measured in the field showed good agreement with the results obtained by theoretical and finite element analysis.

• 정보처리학회논문지B
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• 제13B권5호
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• pp.525-532
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• 2006

아이징(Ising)모델화 된 이진 탁본영상을 유연한 선부합 ICM(Iterated conditional modes) 방식으로 영상복원하는 새로운 기법을 제시한다. 기본적으로 탁본영상은 획 구성상 정보 영역과 배경 영역의 두 극단으로 나누어져야 한다. 종래의 ICM적 접근이 부분적 사각구도(四角構圖)의 점처리에 근거하였음에 비해 본 연구의 주된 아이디어는 선처리이다. 기하학적 구조를 구하기 위해 현재고려중인 화소의 배열 위치를 중심으로 다수의 선형부합함수들을 발생시킨다. 부합함수들의 경사도와 크기들의 집합에 베이즈적 판별 논리를 적용하여 현재고려중인 화소의 영역을 판단한다. 영역판별 결과는 이진 색도이다. 이 경우 매 단계별 영역귀속 판단은 영역 안과 밖에서의 차별된 추적 양상에 관한 확률적 반복성에 의존한다. 마지막으로 시뮬레이션을 통해 이진 탁본영상에 대하여 본 알고리즘의 효과를 확인하였다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 제5회 압연심포지엄 신 시장 개척을 위한 압연기술
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• pp.359-367
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• 2004

In this research on-line model for the prediction of the effective strain distribution in strip on finishing mill process is presented. To describe the effective strain distribution in strip, three guide points and a distribution fitting variable are used. On-line models to get these points and fitting variable non-dimensionalization method and least square method were used with FEM simulation results. The model is developed using strip only FEM simulation as reference sets and compared with roll coupled FEM simulation results as perturbed sets. The on-line model to describe effective strain distribution shows good agreement with coupled FEM analysis results.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1842-1847
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• 2007

In this study, we are to analyze the life and the main failure mode of flexible tubes fitting for pneumatic that are usually applied in the factory automation line. Flexible tubes fitting for pneumatic have complicated failure cause because they are organized as a complex of various elements. Therefore, in this paper, we analyzed the main failure mode of flexible tubes fitting for pneumatic, and then performed life test and performance test according to the international standards. On the basis of these processes, we estimate shape parameter that is the main factor for the calculation of test time for the reliability of flexible tubes fitting for pneumatic and their data analysis of life distribution.

• 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.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 방전 플라즈마 유기절연재료 초전도 자성체연구회
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• pp.25-29
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• 2004

Corona on polymer materials causes deterioration by the combined action of the discharge striking the surface and the action of certain chemical compounds that are formed by the discharges. In the design and manufacture of polymer insulators must be sufficiently large to avoid corona discharges, otherwise a shielding or corona ring (grading ring) needs to be installed on the insulator. To conduct this purpose, many researchers have investigated end-fitting of polymer insulator by voltage distribution simulation and electrical test. Grading rings are used to improve the performance of the insulator in multiple ways. They can reduce corona and associated audible noise and radio influence and television interference. The factors determining the uses of a grading ring are line voltage, geometry and dimensions of end fittings, geometry and dimensions of line hardware, and environmental conditions. In this paper, electrical property of polymer insulator with end-fitting design have been investigated by electrical field analysis, various end-fitting design, tracking wheel test, corona inception voltage and extinction voltage. Electrical field analysis is conducted by FEM program and various end-fitting is designed through this result. Designed end-fittings are manufactured and their performance is conducted by electrical performance test.

• 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.

• 전자공학회논문지
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• 제49권9호
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• pp.362-369
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• 2012

최근에 능동소나 분야에서 분산센서망을 이용하여 표적을 탐지하는 연구가 많이 이루어지고 있다. Zhou 등은 표적의 탐지만 가능한 간단한 구조의 센서들로 구성된 분산센서망에서 라인피팅(line fitting)을 이용하여 표적의 위치를 추정하는 기법을 제안하였다. 이 기법은 ML(Maximum Likelihood) 기법에 비해 3가지 장점을 가지고 있다. 첫째는, 음파전달 모델에 대한 파라미터들을 추정할 필요가 없으며, 둘째는 연산량이 적다. 셋째는 분산센서망에서 센서들이 표적을 탐지했다는 정보만 이용하기 때문에 데이터처리 센터는 적은 량의 데이터만 수집하여도 된다. 그러나 이 기법은 표적의 위치 추정오차가 크다는 단점을 가지고 있다. 본 논문에서는 Zhou의 기법이 가지는 큰 위치 추정오차를 줄이기 위하여 Zhou가 제안한 표적위치 추정기법을 수정하였다. 본 논문에서 제안한 수정된 표적위치 추정기법은 Zhou의 기법보다 40.7%의 위치 추정오차가 감소하는 성능향상을 보였다.

• 한국정보통신학회논문지
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• 제21권2호
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• pp.373-378
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• 2017

온라인 쇼핑 시장이 성장하는 가운데 소비자의 구매 프로세스는 온 오프라인의 경계 없이 복잡해졌고, 지능적인 맞춤형 서비스를 원하는 스마트 컨슈머가 등장하였다. 변화하는 소비자 및 소비 환경에 따라 각 관련 분야의 기업들은 다양한 옴니채널과 O2O 서비스를 제공하고 있으나 패션업계에서의 대응은 많이 늦은 편이다. 그리고 최근에 사물인터넷 환경도 표준화 기반 오픈 플렛폼으로 변화하고 있으며 사물의 유형에 따른 지능적인 서비스의 다양화가 요구되고 있다. 본 논문 에서는 패션업계에 적합한 스마트 피팅 디스플레이를 활용한 패션 O2O 시스템을 제안한다. 제안하는 시스템은 오프라인 매장에서 사용자가 수행한 피팅에 관한 정보를 데이터베이스화하여 사용자에게 제공하며 오프라인에서 수행한 사용자의 활동들을 온라인에서도 지원함으로써, 사용자의 구매활동을 지속적으로 유지, 관리할 수 있도록 한다. 아울러, 매장관리시스템 및 배송시스템의 정보 연계를 통해 고객 중심의 지능적인 피팅 서비스가 가능할 것으로 기대한다.