• 한국수학사학회지
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• 제12권2호
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• pp.69-81
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• 1999

In this paper, I will divide the history of mathematics into four development stages. These are based on significant developments of mathematical concepts or the creation of new fields of mathematics. Then, I will survey the history stages through a study of the characteristic method of research and the most important concepts from each period.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.71-78
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• 2010

The stability analysis of unsaturated infinite slope under rainfall-induced infiltration condition was performed using the generalized effective stress that unifies both saturated and unsaturated condition recently proposed by Lu and Likos(2004, 2006). The Soil-Water Characteristic Curve (SWCC) of the sand with the relative density of 75% was first measured for both drying and wetting processes. The Hydraulic Conductivity Function (HCF) and Suction Stress Characteristic Curve (SSCC) were subsequently estimated. Also, under the rainfall-induced infiltration condition transient seepage analysis of unsaturated infinite slope was performed using the finite element program, SEEP/W. Based on these results, the stability of unsaturated infinite slope under rainfall-induced infiltration condition was examined considering the suction stress. According to the results, the negative pore water pressure and water content within the soil changed with time due to the infiltration. Also, the variation of those caused the variation of suction stress and then the factor of safety of slope changed consequently during the rainfall period.

• 한국제4기학회지
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• 제17권2호
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• pp.13-14
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• 2003

It is generally well known that Quaternary is characteristic geologically in terms of glacial and interglacial repeats and their associated unconformity formation. This paper deals with the first finding of the characteristic and significant meaningful unconformity between Holocene and late Pleistocene, which implies submergence and emergence of the tidal sedimentary basin along the western coastal zone of Korea during interglacial stage(IOS-5e) and glacial time(IOS-2). The stratigraphy of intertidal deposits in the Haenam Bay, western coast of Korea shows two depositional sequence units (Unit I of Holocene and Unit II of late Pleistocene) bounded by an erosional surface of disconformity. The disconformity is related to the latest Pleistocene sea-level lowstands (probably during the LGM). The Unit II is interpreted as intertidal deposit showing tidal sedimentary structures and crab burrow ichnology and has two parts (the upper part and the lower part) showing different lithology and character. The upper part of Unit II shows characteristic subaerial exposure features (emergence) and its related lithology. Such subaerially exposed upper part (more or less 4m to 5m in thickness) is characterized by yellow-brownish sediment color, cryoturbat-ed structure, crab burrow ichnofacies and high value of shear strength. Geochemical and clay mineral analyses of the upper part sediments also indicate subaerial exposure and weathering. In particular, very high value of magnetic susceptibility of the upper part in comparison to that of the lower part is interpreted as pedogenetic weathering during the subaerial exposure period.

• 대한토목학회논문집
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• 제26권2A호
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• pp.273-284
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• 2006

본 연구에서는 근거리지진의 일반적인 특성에 대해 고찰한 후, 탄성응답스펙트럼이 제공하지 못하는 구조물의 비탄성거동에 따른 응답을 연성도 및 항복강도계수의 변화를 이용하여 평가하기 위해 비탄성응답스펙트럼을 작성하였다. 근거리지진의 특성을 가장 잘 반영할 수 있는 장주기의 대상 구조물을 선정하여 탄성 및 비탄성시간이력해석을 수행하였으며, 입력지진동에 대한 응답 분포 양상을 검토하였다. 또한 구조물의 비탄성거동을 명확하게 파악할 수 있도록 소성힌지 발생여부를 검토하여 구조물의 응답특성을 비교 분석하였다.

• 한국의학물리학회지:의학물리
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• 제23권1호
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• pp.1-7
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• 2012

본 연구에서는 환자 고유의 호흡 패턴을 적용하여 호흡의 규칙성을 향상 시킬 수 있는 호흡 연습장치(respiratory training system)를 개발하여, 호흡에 의한 움직임이 고려된 4D-RT (4-dimension radiation therapy) 또는 4D-CT (4-dimension computed tomography) 수행 시 효율성과 정확성을 높이고자 했다. 개발한 호흡연습장치는 푸리에 급수(Fourier series)를 기반으로 환자 고유의 호흡패턴을 만들어 환자에게 편안한 호흡 유도를 제공한다. 호흡연습장치를 사용했을 때 호흡의 규칙성 향상 정도를 알아보기 위하여 5명의 지원자를 대상으로 실험을 진행하였다. 10개의 자유호흡신호를 획득하여 실험 대상자의 고유한 호흡패턴(guiding waveform)을 만들고, 자유호흡(free breathing)을 3분 동안 시행한 후, 고유한 호흡패턴을 이용하여 호흡을 유도하는 신호모니터-호흡(guide breathing)을 3분 동안 시행하여 데이터를 획득하였다. 획득된 자유호흡과 신호모니터-호흡의 데이터를 이용하여 호흡크기(displacement)와 호흡주기(period)의 변동성을 Root mean square error (RMSE)를 적용하여 정량적으로 비교 분석하였다. 호흡의 변동성을 분석한 결과 신호모니터-호흡은 자유호흡과 비교하여 호흡크기의 경우 최대 40%, 호흡주기의 경우 최대 76%까지 RMSE 값이 감소하였으며, 모든 지원자들의 데이터를 분석한 결과 평균적으로 호흡주기의 경우 RMSE 값이 55% 감소되었고, 호흡크기의 경우 33% 감소하였다. 본 연구에서 개발한 호흡연습장치는 실험대상자의 고유한 호흡패턴을 이용하여 규칙적인 호흡을 유도했기 때문에 피실험자는 큰 노력 없이도 신호모니터-호흡을 따라 할 수 있었다. 따라서 규칙적인 호흡을 오랜 시간 지속시킬 수 있다는 측면에서 장점을 가질 수 있으며, 4D RT, 4D CT를 시행 할 경우 규칙적인 호흡을 통해 효율성과 정확성을 향상 시킬 수 있다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1672-1677
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• 2005

The Heat exchanger to be used in the place of business that is presented an utility period comes to be long and the problem of the length of life shares by the manufacture course and using environment factor. Consequentl, it is came to the front problem of inspection, repair, exchange, the utility stopping, safety and confidence. As a result the possibility which the large safety accident can happen comes to be high. It leads mostly to the large accedent when the explosion accident happens. to keep this, The system which the regular period passes to disuse the structure is prepared but The phenomenon which Time and the strength characteristic of the material change, namely Deradation. but It can't be a preventable solution by accident to the damage. Consequentl, This research can take important role to prevent an every kind accident for domestic pressure vessel by evaluating the mechnical characteristic change of meterial, the structure safety and residual life etc.

• 한국실내디자인학회논문집
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• 제16권1호
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• pp.11-20
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• 2007

Modern architecture does a role in terms of connecting traditional and current architecture. In the same time, Which is important part of korean architecture history because of introduction of western architecture. Accordingly, At this meaninglessly going out and leaving of modern architecture, the purpose of this study is systematic researching of 'Cho-sun government-general' interior which is disappeared. I progressed this study to research into the period context at construction of Cho-sun government-general md tendency of architecture and interior at that time. And then understand interior space organization of it. Cho-sun government-general adopted Neo-Baroque style from tendency of that time. Also, showed composite order which is mixed in the Greek temple, the Renaissance and the classic style representing the power. This characteristic is different from current composit order, which is comprehended by our. In order to understand aesthetic value of current straight interior space, It have to be interacted the present and past. But It's averted because it was made in the period of Japanese imperialism. Therefore, We should explore history of interior design that is endowed with sociality and historicity between modern and future interior space as well as current.

• 한국실내디자인학회:학술대회논문집
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• 한국실내디자인학회 2007년도 춘계학술대회 논문집
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• pp.264-269
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• 2007

Modern architecture does a role in terms of connecting traditional and current architecture. In the same time, Which is important part of korean architecture history because of introduction of western architecture. Accordingly, At this meaninglessly going out and leaving of modern architecture, the purpose of this study is systematic researching of the modern Government Office interior. I progressed this study to research into the period context at construction of the modern Government Office and tendency of architecture and interior at that time. And then understand interior space organization of it. The early modern Government Office adopted Neo-Baroque style from tendency of that time. Also, showed composite order which is mixed in the Greek temple, the Renaissance and the classic style representing the power. But, after late 1920 It adopted Modern Style. This characteristic is different from current composit order, which is comprehended by our. In order to understand aesthetic value of current straight interior space, It have to be interacted the present and past. But It's averted because it was made in the period of Japanese imperialism. Therefore, We should explore history of interior design that is endowed with sociality and historicity between modern and future interior space as well as current.

• Structural Engineering and Mechanics
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• 제38권1호
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• pp.65-79
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• 2011

Concrete hydraulic structures such as: Dams, Intake Towers, Piers and dock are usually recognized as" Vital and Special Structures" that must have sufficient safety margin at critical conditions like when earthquake occurred as same as normal servicing time. Hence, to evaluate hydrodynamic pressures generated due to seismic forces and Fluid-Structure Interaction (FSI); introduction to fluid-structure domains and interaction between them are inevitable. For this purpose, first step is exact modeling of water-structure and their interaction conditions. In this paper, the basic equation involved the water-structure-foundation interaction and the effective factors are explained briefly for concrete hydraulic structure types. The finite element modeling of two concrete gravity dams with 5 m, 150 m height, reservoir water and foundation bed rock is idealized and then the effects of fluid domain and bed rock have been investigated on modal characteristic of dams. The analytical results obtained from numerical studies and modal analysis show that the accurate modeling of dam-reservoir-foundation and their interaction considerably affects the modal periods, mode shapes and modal hydrodynamic pressure distribution. The results show that the foundation bed rock modeling increases modal periods about 80%, where reservoir modeling changes modal shapes and increases the period of all modes up to 30%. Reservoir-dam-foundation interaction increases modal period from 30% to 100% for different cases.

• 한국주거학회논문집
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• 제26권6호
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• pp.139-146
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• 2015

In this study, the plane type of main building relics of unified Silla period house site which excavated in Gyeongju city after 1990s was classified and the architectural characteristic of them was investigated. The chronology of building relics in Silla capital city site was mostly known as 8-9th century, and by standard of column arrangement, the plane types of them could be classified as grid type, front veranda-grid type, outer column type. The outstanding characteristic of plane is wide span and open front veranda. In most relics the span were over 4 meters, and inner foundations for small post and strip foundation were found between columns. The front veranda added type buildings were composited of enclosed main room and open front veranda, and column arrangement of them dose not fall into line in most case. Thus it thought that the structures of enclosed main room and open front veranda were independent. The interior space of enclosed main room were divided two rooms by partition wall in some case. In this case, one room is enclosed by wall, and the other room has open front side. This plane is considered for the pleasant life in cold winter and hot summer.