• Korean Journal of Optics and Photonics
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• v.10 no.5
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• pp.373-378
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• 1999

White light scanning interferometry is increasingly used for precision profile metrology of engineering surfaces, but its current application is primarily limited to opaque surfaces with relatively simple optical reflection behaviors. In this paper, a new attempt is made to extend the interferometric method to the thickness profile measurement of transparent thin film layers. An extensive frequency domain analysis of multiple reflection is performed to allow both the top and bottom interfaces of a thin film layer to be measured independently at the same time using nonlinear least squares technique. This rigorous approach provides not only point-by-point thickness probing but also complete volumetric film profiles digitized in three dimensions.

• Publications of The Korean Astronomical Society
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• v.6 no.1
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• pp.16-26
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• 1991

스펙트럼선의 선폭증대 현상을 방출영역 내 기체입자들이 열운동에 의한 단순 도플러 효과로 가정하여 중심에서 어느 한쪽으로 심하게 치우친 스펙트럼 선윤곽를 해석한다. 본 연구에서는 태양활동영역에서 흔히 관측되는 좌우 비대칭의 선윤곽을 서로 다른 가우스속도분포의 기체성분들이 시선방향으로 중첩된 결과라 해석하고, 최소자승법을 이용한 비선형 선윤곽 맞춤질에 의해 스펙트럼 방출영역에서 떨어져 나가는 기채들의 온도 및 분출속도에 관련된 도플러선폭과 도플러이동량을 구하였다.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1993.04a
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• pp.294-300
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• 1993

어떤 무기체계의 임무신뢰도분석에 베이지안기법을 사용하는데 있어 고장율이 주어졌을 때 고장간 시간이 지수분포를 따른다는 가정하에 이의 Conjugate Prior인 감마분포의 추정문제를 다룬다. 임무별 고장간시간에 대한 예측분포를 유도하였으며, 실제 측정된 기존의 임무별 고장간시간이 이 예측분포를 따른다는 전제하에 비선형 최소자승법을 이용하여 감마분포의 두 파라메터를 추정하는 방안을 제시하였다. 또한 대상 무기체계의 실제 고장자료를 이용하여 추정치를 구하였다.

• 한국가스학회:학술대회논문집
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• 2001.10a
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• pp.145-149
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• 2001

• 한국가스학회:학술대회논문집
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• 2000.09a
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• pp.168-173
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• 2000

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1992.08a
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• pp.121-125
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• 1992

입사파와 반사파의 분리는 수리모형실험에 있어서 기본적이면서도 대단히 중요한 문제이다. 최근까지 개발된 분리기법으로는 Goda and Suzuki (1976)의 2점법과 Mansard and Funke (1980)의 3점범을 들 수 있다. 2점법은 두 지점에서의 파고를 관측하여 분리하는 기법으로 두 지점사이의 거리에 따라 해가 존재하지 않는 파랑조건이 존재하며 수조에서 발생되는 횡파, 비선형 파랑상호 간섭, signal noise, 측정오차 등에 민감한 단점이 있다.(중략)

• 한국가스학회:학술대회논문집
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• no.5
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• pp.137-142
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• 2002

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.40 no.4
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• pp.264-274
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• 2003

This paper presents a direct generalized minimum-variance self tuning controller with a PID structure using neural network which adapts to the changing parameters of the nonlinear system with nonminimum phase behavior, noises and time delays. The self-tuning controller with a PID structure is a combination of the simple structure of a PID controller and the characteristics of a self-tuning controller that can adapt to changes in the environment. The self-tuning control effect is achieved through the RLS (recursive least square) algorithm at the parameter estimation stage as well as through the Robbins-Monro algorithm at the stage of optimizing the design parameter of the controller. The neural network control effect which compensates for nonlinear factor is obtained from the learning algorithm which the learning error between the filtered reference and the auxiliary output of plant becomes zero. Computer simulation has shown that the proposed method works effectively on the nonlinear nonminimum phase system with time delays and changed system parameter.

• Korean Journal of Food Science and Technology
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• v.25 no.2
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• pp.178-184
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• 1993

The procedure using equivalent time at reference temperature has been assessed for the estimation of kinetic parameters with experimental data. Kinetic studies of nonenzymatic browning reaction in model and food system were carried out with linearly increasing temperature method. These kinetic parameters, n, $k_{ref}$ and $E_a$ of the systems were evaluated from original data in one step by nonlinear least square regression. The one step procedure yielded efficiently accurate parameter estimation. Computer simulated data with the kinetic models were well consistent with experimental data (average correlation coefficient=0.96).

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.5
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• pp.1104-1111
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• 1990

A method to identify nonlinear elements position of a nonlinear system is presented. Nonlinear elements position can be identified by an equivalent error damping and stiffness matrices which are based on the equivalent linearization technique. The procedures of this technique are: (1) Obtain input force and system response. (2) Define error between the actual and linearized restoring forces. (3) Calculate linearized damping and stiffness coefficients to minimize the square error sum. Several examples are tested and found that these methods are very effective not only to locate the nonlinear elements position but also to identify the degree of nonlinearity qualitatively. Nonlinear type can be qualitatively identified by examining the plots of restoring force vs equivalent state values.