• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2002년도 추계공동학술대회논문집
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• pp.13-19
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• 2002

2-체널 링-코어 프럭스-게이트 콤파스(two-channel ring-core Flux-Gate Compass: FG-Compass)의 성능평가 시스템 설계와 구현방법 및, 다항회귀 모형 기반의 평가 절차와 방법을 기술했다. 성능평가 시스템은 스텝모터 구동 유닛과, 방위정보 전송 유닛, 다항회귀식을 이용한 평가 프로그램 등으로 구성하였다. 성능평가 실험결과, FG-Compass를 전체 잔차 $\pm$4$^{\circ}$, 고유 잔차 $\pm$2$^{\circ}$로 분석하였다. 이 결과는 일반적인 FG-Compass의 고유 잔차 $\pm$4$^{\circ}$와 비교하여 정밀한 것으로, 성능이 향상된 새로운 FG-Compass 설계가 가능함을 나타낸다. 또한, 자동으로 잔차를 추정하고 도정할 수 있는 스마트 FG-Compass 콤파스의 설계론에 관해서도 논의하였다.

• 항공우주시스템공학회지
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• 제13권2호
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• pp.51-59
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• 2019

이번 연구에서는 앞서 Part I [1]에서 수행한 단일-셀(single-cell) 모델에 이어, 시위 방향으로 비대칭성 단면을 가지는 다중-셀(multi-cell) 복합재료 박벽보(thin-walled beam) 모델을 선정하여, 단면의 형상에 대한 이론적인 동특성을 해석하였다. 이를 위해 와핑 구속 효과와 전단 변형 효과, 보의 테이퍼비와 단면비 등을 고려하였다. Part I에서와 마찬가지로 다중-셀 단면의 질량 및 강성 계수와 고유 진동수 등의 특성을 조사하였다. 특히, 다중-셀과 단일-셀 단면을 비교하고, 다중-셀 단면의 고유 진동수에 미치는 테이퍼비와 단면비의 영향을 비교 분석하였다. 또한, 단면의 비대칭성과 와핑 함수를 보정하지 않은 경우에 대해 그 결과를 비교하였다.

• Advances in nano research
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• 제12권5호
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• pp.467-482
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• 2022

In the current work, static and free torsional vibration of functionally graded (FG) nanorods are investigated using Fourier sine series. The boundary conditions are described by the two elastic torsional springs at the ends. The distribution of functionally graded material is considered using a power-law rule. The systems of equations of the mechanical response of nanorods subjected to deformable boundary conditions are achieved by using the modified couple stress theory (MCST) and taking the effects of torsional springs into account. The idea of the study is to construct an eigen value problem involving the torsional spring parameters with small scale parameter and functionally graded index. This article investigates the size dependent free torsional vibration based on the MCST of functionally graded nano/micro rods with deformable boundary conditions using a Fourier sine series solution for the first time. The eigen value problem is constructed using the Stokes' transform to deformable boundary conditions and also the convergence and accuracy of the present methodology are discussed in various numerical examples. The small size coefficient influence on the free torsional vibration characteristics is studied from the point of different parameters for both deformable and rigid boundary conditions. It shows that the torsional vibrational response of functionally graded nanorods are effected by geometry, small size effects, boundary conditions and material composition. Furthermore, for all deformable boundary conditions in the event of nano-sized FG nanorods, the incrementing of the small size parameters leads to increas the torsional frequencies.

• 한국소음진동공학회논문집
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• 제18권10호
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• pp.1042-1048
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• 2008

Disc brake noise is an important customer satisfaction and warranty issue for many manufacturers as indicated by technical literature regarding the subject coming from Motor Company. This research describes results of a study to assess disk brake squeal propensity using finite element methods and optimal technique (Kriging). In this study, finite element analysis has been performed to determine likely modes of brake squeal. This paper deals with friction-induced vibration of disc brake system under contact friction coefficient. A linear, finite element model to represent the floating caliper disc brake system is proposed. The complex eigen-values are used to investigate the dynamic stability and in order to verify simulations which are based on the FEM model. In this paper, Kriging from among the meta-modeling techniques is proposed for an optimal design scheme to reduce the brake squeal noise.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.185-189
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• 2004

For face recognition system, a face detector which can find exact face region from complex image is needed. Many face detection algorithms have been developed under the assumption that background of the source image is quite simple . this means that face region occupy more than a quarter of the area of the source image or the background is one-colored. Color-based face detection is fast but can't be applicable to the images of which the background color is similar to face color. And the algorithm using neural network needs so many non-face data for training and doesn't guarantee general performance. In this paper, A multi-scale, multi-face detection algorithm using PCA is suggested. This algorithm can find most multi-scaled faces contained in static images with small number of training data in reasonable time.

• 품질경영학회지
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• 제21권2호
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• pp.215-223
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• 1993

A paired comparison which is a method of comparative judgements is widely used to increase the amount of information transmitted to human sense organ. In this study, a paired comparison method is proposed for the discrimination capacity and preference analysis of non-skilled sensory inspectors. We consider on order effect, that is, difference of evaluation occurred as a result of sample presentation by random order. The purpose of this paper is to determine a sample with the highest preference degrees by analyzing a discrimination capacity and evaluating preference degrees of sensory inspectors. An analysis of a discrimination capacity is bared on the capacity index obtained by an eigen-vector method and an evaluation of preference degrees is performed by a significance test.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2009년도 학술대회
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• pp.197-202
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• 2009

Active Appearance Models(AAMs)은 얼굴인식, 얼굴추적, 표정인식 뿐만 아니라 눈동자 추적과 같은 분야에도 적용되어 좋은 성능을 보여 주었다. 보통 AAM 을 생성하기 위해서는 얼굴 영상과 얼굴의 특징을 나타내는 점으로 구성된 매쉬로 이루어 지는 트레이닝 셋이 필요하다. AAM fitting algorithm 은 학습한 얼굴과 유사한 얼굴을 Fitting 할 때에는 뛰어난 성능을 보이지만 조명에 의한 그림자 또는 액세서리에 의한 얼굴의 피부 가림과 같이 전체 얼굴이 잘 나타나지 않는 불완전한 영상의 Fitting 은 입력영상과 템플릿 영상간의 오차가 커지기 때문에 실패할 가능성이 매우 높다. 본 논문에서 우리는 AAMs 에서 사용되는 PCA를 Higher-order Singular Value Decomposition(HOSVD)로 대체하여 이 문제를 보완하는 강화된 AAM 을 제안한다. 제안된 AAM 에는 기존에 사용하던 고유벡터와 함께 HOSVD 를 통해 획득할 수 있는 Eigen-Modes 를 추가하여 사용한다. 또한 우리는 Yale Face Database를 이용한 평가를 통해 제안된 AAM 이 기존 AAM 보다 불완전한 영상에 효과적으로 대응하는 것을 보여준다.

• 대한기계학회논문집A
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• 제36권11호
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• pp.1319-1326
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• 2012

본 논문은 구동력이 자전거의 self-stability 에 미치는 영향을 해석한다. 운전자의 제어를 고려하지 않는 자전거의 self-stability 는 자전거의 선형 모델로부터 고유치를 구하여 해석 할 수 있다. 전륜과 후륜에 작용하는 자전거 구동력을 고려한 선형모델을 개발하고 이로부터 구동력이 안정성에 미치는 영향을 규명하였다. 선형모델의 결과가 다물체 동역학 모델의 시뮬레이션을 통한 비선형 자전거 모델에서도 같은 결과를 보임을 확인하였다.

• The Journal of the Acoustical Society of Korea
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• 제24권1E호
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• pp.21-27
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• 2005

Environmental mismatch has been one of important issues discussed in matched field processing for underwater source detection problem. To overcome this mismatch many algorithms professing robustness have been suggested. Feature extraction method (FEM) [Seong and Byun, IEEE Journal of Oceanic Engineering, 27(3), 642-652 (2002)] is one of robust matched field processing algorithms, which is based on the eigenvector estimation. Excluding eigenvectors of replica covariance matrix corresponding to large eigenvalues and forming an incoherent subspace of the replica field, the processor is formulated similarly to MUSIC algorithm. In this paper, by using the ocean experimental data, processing results of FEM and MVDR with white noise constraint (WNC) are presented for two levels of multi-tone source. Analysis of eigen-space of CSDM and FEM performance are also presented.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.756-759
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• 2001

The purpose of this paper is to investigate the buckling and dynamic characteristics for the cylindrical shell under shear loading. To do this, a vibration model tests and analyses and static buckling analyses were performed for the reduced scale model of nuclear reactor vessel. From the results of vibration modal analysis with the pre-shear displacement loads, it is known that the beam vibration mode is not affected by the shear displacement, however shell vibration modes are significantly affected by it. As the pre-shear displacement increases to the critical buckling displacement, the 1st shell vibration frequency in greatly reduces and approaches to zero value.