• 한국지반공학회지:지반
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• 제13권1호
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• pp.123-136
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• 1997

구조물의 형상 변화를 연속적으로 고려할 수 있는 유한요소법 원리에 기초하여 탄성지반내에 단계적 터널굴착시 임의의 굴착단계에서 발생한 증분변위와 굴착전 암반내에 존재하는 초기응력의 크기가 선형관계에 있음을 유도하였다. 즉, 총변위가 아닌 임의 단계에서 계측된 증분변위만으로 탄성지반내 초기음력의 역산이 가능함을 이론적으로 증명하였다. 이러한 이론적 관계식에 기초하여 다단계 터널굴착시 계측된 증분변위를 이용하여 초기응력을 역산할 수 있는 역해석 프로그램을 작성하였다. 간단한 예제를 통하여 구성한 프로그램의 정확성과 현장 적용 가능성을 검토하였다.

• 한국생산제조학회지
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• 제9권5호
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• pp.119-126
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• 2000

Recently, according to the various taste of consumers, the design of a product is changed variously and complicatedly. The complicated product is not usually constructed with one path but multi-path. By the way, in machining, higher precision and the reduction of leading and machining time is required. But, for the multi-patch sculptured surface, the amount of machining data becomes large. This means the increase of leading and machining time. In this study, the tool path generation method with reparameterization is proposed for multi-patch sculptured surface and variable step size using NURBS is used to satisfy the precision and to reduce leading and machining time.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2006년도 정기 학술대회 논문집
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• pp.623-630
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• 2006

In this paper, a geometric nonlinear analysis procedure of beam-column element including multi-noded cable element is presented. For this, first a stiffness matrix about beam-column element which considers the second effect of initial force supposing the curved shape at each time step with Hermitian polynomials as the shape function is derived and second, tangent stiffness matrix about multi-noded cable element being too. To verify geometric nonlinearity of this newly developed multi-noded cable-truss element, IPS(Innovative Prestressed Support) system using this theory is analysed by geometric nonlinear method and the results are compared with those by linear analysis.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.647-652
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• 2000

Recently, according to the various taste of consumers, the design of a product is changed variously and complicatedly. The complicated product is not usually constructed with one patch but multi-patch. By the way, in machining, higher precision and the reduction of leading and machining time is required. But for the multi-patch sculptured surface, the amount of machining data becomes large. This means the increase of leading and machining time. In this study, the tool path generation method with reparameterization is proposed for multi-patch sculptured surface and variable step size using NURBS is used to satisfy the precision and to reduce leading and machining time.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.262-265
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• 2007

Preliminary results are reported on ship detection using coherence images computed from cross-correlating images of multi-look-processed dual-polarization data (HH and HV) of ENVISAT ASAR. The traditional techniques of ship detection by radars such as CFAR (Constant False Alarm Rate) rely on the amplitude data, and therefore the detection tends to become difficult when the amplitudes of ships images are at similar level as the mean amplitude of surrounding sea clutter. The proposed method utilizes the property that the multi-look images of ships are correlated with each other. Because the inter-look images of sea surface are covered by uncorrelated speckle, cross-correlation of multi-look images yields the different degrees of coherence between the images and water. The polarimetric information of ships, land and intertidal zone are first compared based on the cross-correlation between HH and HV. In the next step, we examine the technique when the dual-polarization data are split into two multi-look Images.

• 대한치과보철학회지
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• 제48권4호
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• pp.243-250
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• 2010

연구 목적: 본 연구는 잘 맞는 임플란트 상부구조물에서 서로 다른 나사조임순서와 조임방법이 나사의 풀림토크값에 미치는 영향을 평가하였다. 연구 재료 및 방법: 서로 수동적 적합 관계를 갖는 완전 무치악 하악 주모형과 네 개의 평행한 임플란트 (Astra Tech)에 직접 연결되는 금속구조물을 제작하였다. 금속구조물과 잘 맞는 실험모형을 위해 주모형에서 연결인상법을 이용하여 여섯 개의 경석고 모형을 얻었다. 20 Ncm로 조인 후 나사의 풀림토크값을 두 번 측정하였다. 세 가지 나사조임순서 (1-2-3-4, 2-4-3-1, 그리고 2-3-1-4)와 두 가지 나사조임방법 (two-step과 one-step)에 대한 나사의 풀림토크값과 최소풀림토크값을 유의수준 .05에서 각각 다원분산분석법 (multi-way ANOVA)과 이원분산분석법 (two-way ANOVA)을 이용하여 통계분석 하였다. 결과: 나사조임순서에 대한 나사의 평균 풀림토크값은 12.8 Ncm (2-4-3-1)에서 13.1 Ncm (2-3-1-4)의 값을 보였고, 나사조임방법에 대한 값은 13.1 Ncm (two-step)와 11.8 Ncm (one-step)였다. 나사조임순서에 대한 나사의 평균 최소풀림토크값은 11.1 Ncm (1-2-3-4)와 11.2 Ncm (2-4-3-1과 2-3-1-4)였고, 나사조임방법에 대한 값은 11.2 Ncm (two-step)와 9.9 Ncm (one-step)였다. 나사의 풀림토크값과 최소풀림토크값은 세 가지 나사조임순서 간에 통계학적으로 유의성 있는 차이가 없었다. 그러나 두 가지 나사조임방법 간에는 두 값 모두 통계학적으로 유의성 있는 차이가 있었다. 나사를 두 단계로 나누어 조이는 방법이 한 번에 조이는 방법보다 더 큰 풀림토크값 (P = .0003)과 더 큰 최소풀림토크 값 (P = .0035)을 보였다. 결론: 본 연구와 같은 조건하에서, 연결인상법으로 얻은 잘 맞는 임플란트 상부구조물에 있어서 나사조임순서는 나사의 풀림토크값에 영향을 미치는 중요한 요소는 아니었다. 그러나 나사를 두 단계로 나누어 조이는 방법은 한 번에 조이는 방법보다 더 큰 풀림토크값을 보였다.

• Current Optics and Photonics
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• 제2권4호
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• pp.332-339
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• 2018

A new multi-frequency fringe projection method is proposed to reduce the nonlinear phase error in 3-D shape measurements using an adaptive compensation method. The phase error of the traditional fringe projection technique originates from various sources such as lens distortion, the nonlinear imaging system and a nonsinusoidal fringe pattern that can be very difficult to model. Inherent possibility of phase error appearing hinders one from accurate 3-D reconstruction. In this work, an adaptive compensation algorithm is introduced to reduce adaptively the phase error resulting from the fringe projection profilometry. Three different frequencies are used for generating the gratings of projector and conveyed to the four-step phase-shifting procedure to measure the objects of very discontinuous surfaces. The 3-D shape results show that this proposed technique succeeds in reconstructing the 3-D shape of any type of objects.

• 한국공간구조학회논문집
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• 제13권2호
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• pp.75-82
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• 2013

For each cable component in a cable dome structure, pre-tension is needed for stability of whole the structure. The summation of these pre-tension at each joint should be zero to achieve the self equilibrium structure. The first step in cable dome structure analysis is to find the ratio of pre-tension in each member which can produce a stable and structure on self-equilibrium. In this paper, a new method based on the basic principle of closed force polygon for equilibrium system is proposed for the determination of self-equilibrium mode of cable dome structure. A single layer cable dome and two multi layer type domes have been analyzed. The ratios of cable members are determined by the presented method, and check the validation of the results by numerical calculation.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 추계학술대회 논문집
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• pp.741-742
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• 2008

• 전자공학회논문지C
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• 제35C권8호
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• pp.68-74
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• 1998

The neural network predictiv econtroller (NNPC) is proposed for the attempt to mimic the function of brain that forecasts the future. It consists of two loops, one is for the prediction of output (NNP:neural network predictor) and the other one is for control the plant(NNC: neural network controller). The output of NNC makes the control input of plant, which is followed by the variation of both plant error and predictin error. The NNP forecasts the future output based upon the current control input and the estimated control output. The input and the output data of a system and a new method using evolution strategy are used to train the NNP. A two-step NNPC is applied to control the temeprature in boiler systems. It was compared with PI controller and auto-tuning PID controller. The computer simulaton and experimental results show that the proposed method has better performances than the other method.