• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1998년도 가을 학술발표회 논문집
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• pp.297-304
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• 1998

• Structural Engineering and Mechanics
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• 제7권2호
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• pp.217-224
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• 1999

A semi-stochastic process model of reliability was established for hyperbolic cooling towers subjected to combined loadings of wind force, self-weight, temperature loading. Effect of the soil-structure interaction on reliability was evaluated. By involving the gust factor, an equivalent static scheme was employed to convert the dynamic model to static model. The TR combination rule was used to consider relations between load responses. An analysis example was made on the 90M cooling tower of Maoming, Guangdong of China. Numerical results show that the design not including interaction turns to be conservative.

• 한국지반공학회논문집
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• 제16권6호
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• pp.79-85
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• 2000

본 논문에서는 사질토 지반에 일정기간 계속하여 증가되는 단계별 하중이 작용할 때 발생할수 있는 지반의 밀도화 현상을 hyperbolic model의 매개변수 변화를 고려한 방법으로 유한요소법에 의한 수치적 침하해석에 반영해 주었다. 이를 위해 사질토의 상대밀도별 삼축압축실험을 실시하여 매개변수를 산정하였으며, 이를 토대로 각각의 상대밀도의 변화에 따른 매개변수값을 Lagrange의 다항식 수치보간법으로 프로그램에 반영하였다. 또한 유한요소프로그램 내에서 요소의 체적을 계산하고 체적의 변화를 상대밀도 개념으로 접근함으로서 지반의 밀도화를 프로그램내에서 모사할수 있도록 하였다. 본 연구에서 개발한 해석 프로그램에 의한 지반의 밀도화현상의 모사 결과를 실내 모형기초재하실험에 의하여 비교 분석해 본 결과 기존의 해석 보다 향상된 결과를 나타냄을 알 수 있었다.

• 한국농공학회논문집
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• 제47권1호
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• pp.61-68
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• 2005

In this study, it was proposed that an equation for predicting consolidation settlement on soft clay ground, which separate total settlement into primary and secondary consolidation settlement equation. The consolidation settlements by the proposed equation and by the measured settlements from laboratory model test were compared and verified for its application. It was appeared that the proposed equation from the laboratory model test approach to be more realistic comparing to !the result of Terzaghi's equation. From the above application, it was concluded that the final settlement prediction by. the Hyperbolic, Asaoka methods is needed to the initial settlement but the proposed equation could be much applicable in the lacking condition of measured data of the initial period.

• 한국산학기술학회논문지
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• 제16권3호
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• pp.2117-2122
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• 2015

한 장의 영상에 보다 많은 영상정보를 담기 위해서는 넓은 시야각이 필요하다. 넓은 시야각을 갖는 영상은 보안, 감시, 원격화상회의, 이동로봇 등의 산업분야에서 사용된다. 본 논문에서는 광각의 파노라마 영상을 획득하기 위해 쌍곡면 실린더형 반사체를 이용한 영상획득 방법을 제안한다. 일반적인 응용 예에서 수직화각 보다 수평화각이 중요하므로 수직방향으로는 평면거울과 같고, 수평방향으로 쌍곡선 형태를 갖는 실린더형 반사체를 설계하였다. 광학적 성능 분석을 위해 광선추적법을 통해 본 쌍곡면 실린더형 반사체 영상계의 영상획득 모델을 구하였으며, 쌍곡면 실린더형 반사체를 실제 제작하였고, 영상 실험을 통해 광각 영상획득 성능을 검증하였다. 제안하는 영상 시스템은 기존 방법에 비해 경제적이며, 별도의 영상처리 없이 수평화각 210도에 이르는 광각의 실시간 파노라마 영상을 획득할 수 있었다.

• 산업기술연구
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• 제28권B호
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• pp.91-99
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• 2008

Applicability of existing methods of predicting consolidation settlement was assessed by analyzing results of centrifuge tests modelling self-weight consolidation of soft marine clay. From extensive literature review about self-weight consolidation of soft marine clays located in southern coast in Korea, constitutive relationships of void ratio-effective stress-permeability and typical self-weight consolidation curves with time were obtained by centrifuge model experiments. For the condition of surcharge loading, exact solution of consolidation settlement curve was obtained by Terzaghi's consolidation theory and was compared with the results predicted by currently available methods such as Hyperbolic method, Asaoka's method, Hoshino's method and ${\sqrt{S}}$ method. All methods were found to have their own inherent error to predict final consolidation settlement. From results of analyzing the self-weight consolidation with time by using those methods, Asaoka's method predicted the best. Hyperbolic method predicted relatively well in error range of 2~24% for the case of showing the linearity in the relationship between T vs T/S in the stage of consolidation degree of 60~90 %. For the case of relation curve of T vs $T/S^2$ showing the lineality after the middle stage, error range from Hoshino method was close to those from Hyperbolic method. However, Hoshino method is not able to predict the final settlement in the case of relation curve of T vs $T/S^2$ being horizontal. For the given data about self-weight consolidation after the middle stage, relation curve of T vs T/S from ${\sqrt{S}}$ method shows the better linearity than that of T vs $T/{\sqrt{s}}$ from Hyperbolic method.

• 농업과학연구
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• 제25권2호
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• pp.235-246
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• 1998

지반의 압밀에 따른 변형 거동을 분석하고 입력정수들의 영향을 알아보기 위해서 쌍곡선 모델과 수정 Cam-Clay 모델을 사용하여 수치해석하고 실측자료와 비교한 결과 다음과 같은 결과를 얻었다. 1. 압밀계수 산정밥법에 대한 신뢰성을 평가한 결과, 정규압밀영역에서는 모두 유사한 값을 나타냈으나, 과압밀영역에서는 변화 폭이 커서 적합한 압밀계수를 산정하는데 문제점이 있는 것으로 나타났다. 2. 수치해석에 의하여 전반적인 수평변위의 거동을 파악할 수 있으며, 현장 실측치를 기초로 성토하중에 의한 연약지반의 단기적인 안정성을 파악하는데는 쌍곡선 방법을 적용하는 것이 적합하다. 3. 수평변위의 영향범위(L)는 성토체의 선단으로부터 전체연약층(H)의 L=(0.7~1.4)H 범위까지 미치는 것으로 나타났으며, 최대수평변위는 성토체의 선단하부 G.L.-10m지점으로 전체 연약층 깊이의 1/3지점에서 발생하였다. 4. 쌍곡선 모델과 수정 Cam-Clay 모델을 이용하여 연약지반의 침하량을 비교분석한 결과 침하량의 크기는 Curve fitting 방법, 수정 Cam-Clay 모델, 쌍곡선모델 순으로 나타났다. 5. 쌍곡선 모델과 수정 Cam-Clay 모델에서 입력변수의 영향을 알아보기 위해서 각각의 입력변수들을 변화시켜 침하량과 수평변위의 변화를 비교한 결과, 쌍곡선모델에서는 K값의 영향이 가장 크게 나타났고, 수정 Cam-Clay 모델에서는 침하량은 ${\Gamma}$값의 영향이 가장 크고, 측방변위는 M값의 영향이 가장 크게 나타났다.

• 대한기계학회논문집B
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• 제22권1호
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• pp.1-11
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• 1998

For the analysis of phonon heat transfer within short time and spatial scales, conventional macroscopic heat conduction equations with jump boundary conditions are tried and the results are compared to those of equation of phonon radiative transport(EPRT), which is one of microscopic transport equation. In transient state the macroscopic temperatures show far different behavior from EPRT. In steady state the hyperbolic temperatures with temperature jump at the wall from time relaxation model agrees well with EPRT temperatures. Since EPRT is also an approximate form of microscopic transport equation and there are no experimental results to verify the proposed model in this study, we can not conclude whether the approaching method from this study is valid or not. To the authors' knowledge, there are no experimental results available which can be used to test the validity of these models. Such an experiment, while difficult to conduct, would be invaluable.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 말뚝기초 학술발표회
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• pp.85-106
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• 2000

The load distribution and deformation of drilled shafts subjected to axial loads were evaluated by a load transfer approach. The emphasis was on quantifying the load transfer mechanism at the interface between the shafts and surrounding highly weathered rocks based on a numerical analysis and small-scale tension load tests performed on nine instrumented piles. An analytical method that takes into account the soil coupling effect was developed using a modified Mindlin's point load solution. Based on the analysis, a single-modified hyperbolic model is proposed for the shear transfer function of drilled shafts in highly weathered rocks. Through comparisons with field case studies, it is found that the prediction by the present approach is in good agreement with the general trend observed by in-situ measurements.

• Smart Structures and Systems
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• 제6권2호
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• pp.101-113
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• 2010

This paper presents the results of a series of experiments conducted to model a magnetorheological damper operated in shear mode. The prototype MR damper consists of two parallel steel plates; a paddle covered with an MR fluid coated foam is placed between the plates. The force is generated when the paddle is in motion and the MR fluid is reached by the magnetic field of the coil in one end of the device. Two approaches were considered in this experiment: a parametric approach based on the Bingham, Bouc-Wen and Hyperbolic Tangent models and a non parametric approach based on a Neural Network model. The accuracy to reproduce the MR damper behavior is compared as well as some aspects related to performance are discussed.