• 한국강구조학회 논문집
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• 제10권4호통권37호
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• pp.577-587
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• 1998

본 연구에서는 열차하중이 강합성형 철도교의 동적응답에 미치는 영향을 연구하였다. 2개의 I-거더와 가로보로 구성된 판형교는 판요소와 공간뼈대요소를 이용하여 모델링하였으며, 상판과 주형의 offset은 완전합성을 가정하여 구속방정식을 이용하여 연결하였으며 트랙구조는 고전적인 탄성지반위의 보 이론을 사용하여 이상화하였다. 2PC+2MT+161T로 구성된 TGV열차의 수직처짐과 피칭회전을 고려한 2차원 수치모델을 개발하였다. 또한, 속도의존적 제동함수를 사용하여 열차의 제동을 고려하였다. 이동열차하중에 의한 교량의 동적거동 파악을 위하여 교량의 고유진동수 변화, speed parameter, 차량모델링 방법, 열차의 제동 등에 대한 매개변수연구를 수행하였다.

• 한국강구조학회 논문집
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• 제11권4호통권41호
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• pp.397-407
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• 1999

본 연구는 공칭응력 및 변동응력을 이용한 현수교 횡프레임의 피로안전성 평가를 위하여 수행되었으며, 본 논문에서는 해석모델의 모형화 방법 및 공칭응력을 이용한 피로안전성 평가를 주요 내용으로 다루었다. 본 연구의 목적에 부합되는 해석모형을 도출 하고자 해석모형의 지지조건에 따른 영향, 평면해석과 입체해석간의 구조해석 결과의 차이 및 모형화되는 횡프레임 수의 영향에 대해서 검토하였다. DB-24하중을 피로조사하중으로 이용하였으며, 단일트럭하중에 의한 발생응력을 조합하여 실교통류 흐름의 효과를 고려하였다. 피로검토대상 구조상세에 대해 산출된 공칭응력을 국내 및 국외의 피로등급과 비교하고 그 결과에 대해 고찰하였다.

• 정보처리학회논문지B
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• 제17B권6호
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• pp.405-412
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• 2010

기존의 배경 생성방법은 주로 시간에 따른 context만을 이용해 복잡한 환경에서는 적용하기 힘들다. 이러한 단점을 해결하기 위해, 본 논문에서는 움직이는 물체를 포함하지 않는 배경 영상을 생성하기 위해 시간에 따른 context와 공간에 따른 context를 융합한 새로운 배경 생성 방법을 제안한다. 제안한 방법은 먼저 샘플링된 프레임 이미지를 m*n의 블록으로 나누고 각각의 블록을 고정 블록과 비고정 블록으로 나눈다. 비고정 블록에 대해서, 각 블록의 시간적 context와 공간적 context를 모델링하기 위해 MRF 프레임워크를 이용한다. MRF 프레임워크는 영상 픽셀과 연관된 특징과 같은 context에 독립된 entity를 모델링하는데 많이 이용되는 방법으로 본 논문에서는 비고정 블록에 대한 시간적 context와 공간적 context를 모델링하기 위해 이용된다. 실험결과는 제안한 방법이 기존의 시간에 따른 context만을 이용했을 경우보다 더 효율적임을 보여준다.

• 한국실내디자인학회논문집
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• 제19권6호
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• pp.100-111
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• 2010

'Pattern' is the term that is frequently used in the aspects of history, society, and science. It always appears in the remains or relics of the age of civilization when recording was started, and its evaluation and value differ by time. Patterns in the ancient civilization were symbolic, social, and spatially crucial. However, after the modernization, they were considered to be immoral and unnecessary, so the range of their significance came to reduce. Due to the development of science, ornament patterns lost the limitation of its range of use along with new interpretation of them. Especially with the advent of new scientific theories such as the evolution theory from the biological aspect, quantum mechanics, and super string theory, morphological possibilities more than the human scale perceived by men came to be discovered. Living organisms maintain their lives through patterns, structures, and processes in order to produce a system alive. Among them, patterns are the organization of relations determining the characteristics of the system. The present patterns may correspond to this meaning. The pattern in a space is the matter of how to relate the components after all. In a space, however, there are numerous components mingled with one another. If these tasks are conducted as analogue work, it will take a lot of time and effort. However, if digital media are utilized to perform the tasks like analysis, generation, or fabrication, it will produce a result with higher precision and efficiency. In this sense, parametric modeling is quite useful media. Opening morphological variation, it realizes more possibilities, connects conveniently the relations between complex components composing a space, and helps produce creative patterns.

• 한국항공우주학회지
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• 제45권11호
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• pp.922-931
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• 2017

본 논문에서는 신규 방식의 발사관 덮개인 분리식 덮개의 설계과정과 해석 및 실험적 검증결과에 대하여 기술하였다. 발사관 덮개에 보편적으로 사용되고 있는 종래의 파열식 및 구동기 방식의 덮개의 단점을 극복하기 위하여 폭발볼트 및 스프링 레버를 이용한 분리식 덮개를 제안하였다. 분리식 덮개는 폭발볼트와 스프링 레버 구동시스템으로 단순하게 구성되어 있다. 첫 번째로, 수학적 모델에 의해 제시된 설계제원에 대하여 다물체 동역학 해석을 통하여 기계적 작동성능에 관한 검토를 실시하였다. 도출된 해석결과는 이후 초고속 카메라로 획득한 계측 결과와 잘 부합하였다. 또한 작동성능에 대한 설계인자별 영향을 파악하기 위한 경향분석이 수행되었다. 본 연구를 통해 구조적 단순성과 가격의 효율성을 보유한 신규방식의 발사관 덮개를 군수분야에 제시하는데 기여했다고 판단되며 특별히 다연장 발사관 시스템(MLRS)에 유용하게 적용될 것이라고 예상된다.

• Structural Engineering and Mechanics
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• 제49권1호
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• pp.95-110
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• 2014

The study deals with physical modeling of space frame-pile foundation and soil system using finite element models. The superstructure frame is analyzed using complete three-dimensional finite element method where the component of the frame such as slab, beam and columns are descretized using 20 node isoparametric continuum elements. Initially, the frame is analyzed assuming the fixed column bases. Later the pile foundation is worked out separately wherein the simplified models of finite elements such as beam and plate element are used for pile and pile cap, respectively. The non-linear behaviour of soil mass is incorporated by idealizing the soil as non-linear springs using p-y curve along the lines similar to that by Georgiadis et al. (1992). For analysis of pile foundation, the non-linearity of soil via p-y curve approach is incorporated using the incremental approach. The interaction analysis is conducted for the parametric study. The non-linearity of soil is further incorporated using iterative approach, i.e., secant modulus approach, in the interaction analysis. The effect the various parameters of the pile foundation such as spacing in a group and configuration of the pile group is evaluated on the response of superstructure owing to non-linearity of the soil. The response included the displacement at the top of the frame and bending moment in columns. The non-linearity of soil increases the top displacement in the range of 7.8%-16.7%. However, its effect is found very marginal on the absolute maximum moment in columns. The hogging moment decreases by 0.005% while sagging moment increases by 0.02%.

• Smart Structures and Systems
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• 제3권1호
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• pp.51-68
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• 2007

High-strength concrete (HSC) is becoming increasingly attractive for various construction projects since it offers a multitude of benefits over normal-strength concrete (NSC). Unfortunately, current design provisions for shear capacity of RC slender beams are generally based on data developed for NSC members having a compressive strength of up to 50 MPa, with limited recommendations on the use of HSC. The failure of HSC beams is noticeably different than that of NSC beams since the transition zone between the cement paste and aggregates is much denser in HSC. Thus, unlike NSC beams in which micro-cracks propagate around aggregates, providing significant aggregate interlock, micro-cracks in HSC are trans-granular, resulting in relatively smoother fracture surfaces, thereby inhibiting aggregate interlock as a shear transfer mechanism and reducing the influence of compressive strength on the ultimate shear strength of HSC beams. In this study, a new approach based on genetic algorithms (GAs) was used to predict the shear capacity of both NSC and HSC slender beams without shear reinforcement. Shear capacity predictions of the GA model were compared to calculations of four other commonly used methods: the ACI method, CSA method, Eurocode-2, and Zsutty's equation. A parametric study was conducted to evaluate the ability of the GA model to capture the effect of basic shear design parameters on the behaviour of reinforced concrete (RC) beams under shear loading. The parameters investigated include compressivestrength, amount of longitudinal reinforcement, and beam's depth. It was found that the GA model provided more accurate evaluation of shear capacity compared to that of the other common methods and better captured the influence of the significant shear design parameters. Therefore, the GA model offers an attractive user-friendly alternative to conventional shear design methods.

• Structural Engineering and Mechanics
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• 제17권3_4호
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• pp.527-537
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• 2004

Consequence-Based Engineering (CBE) is a new paradigm proposed by the Mid-America Earthquake Center (MAE) to guide evaluation and rehabilitation of building structures and networks in areas of low probability - high consequence earthquakes such as the central region of the U.S. The principal objective of CBE is to minimize consequences by prescribing appropriate intervention procedures for a broad range of structures and systems, in consultation with key decision makers. One possible intervention option for rehabilitating unreinforced masonry (URM) buildings, widely used for essential facilities in Mid-America, is passive energy dissipation (PED). After the CBE process is described, its application in the rehabilitation of vulnerable URM building construction in Mid-America is illustrated through the use of PED devices attached to flexible timber floor diaphragms. It is shown that PED's can be applied to URM buildings in situations where floor diaphragm flexibility can be controlled to reduce both out-of-plane and in-plane wall responses and damage. Reductions as high as 48% in roof displacement and acceleration can be achieved as demonstrated in studies reported below.

• Earthquakes and Structures
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• 제14권5호
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• pp.399-409
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• 2018

The dynamic response and seismic damage of single-layer reticulated shells in the near field of a rupturing fault can be different from those in the far field due to the different characteristics in the ground motions. To investigate the effect, the dynamic response and seismic damage of this spatial structures subjected to two different ground motions were numerically studied by nonlinear dynamic response analysis. Firstly, twelve seismic waves with an apparent velocity pulse, including horizontal and vertical seismic waves, were selected to represent the near-fault ground motion characteristics. In contrast, twelve seismic records recorded at the same site from other or same events where the epicenter was far away from the site were employed as the far-fault ground motions. Secondly, the parametric modeling process of Kiewitt single-layer reticulated domes using the finite-element package ANSYS was described carefully. Thirdly, a nonlinear time-history response analysis was carried out for typical domes subjected to different earthquakes, followed by analyzing the dynamic response and seismic damage of this spatial structures under two different ground motions based on the maximum nodal displacements and Park-Ang index as well as dissipated energy. The results showed that this spatial structures in the near field of a rupturing fault exhibit a larger dynamic response and seismic damage than those obtained from far-fault ground motions. In addition, the results also showed that the frequency overlap between structures and ground motions has a significant influence on the dynamic response of the single-layer reticulated shells, the duration of the ground motions has little effects.

• 한국산학기술학회논문지
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• 제11권8호
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• pp.3083-3093
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• 2010

최근 3D파라메트릭 모델링 기법의 발달에 힘입어 비정형 건축 프로젝트가 증가하고 있다. 기존의 BIM 시뮬레이션 의사결정 지원시스템은 가상현실에서 구현되기 때문에 효율적이지 못했다. 이에 본 연구에서 효율적 의사결정지원을 위한 증강현실 기반 시뮬레이션 시스템인 "AR naviX"를 개발하였다. 이 시뮬레이션 시스템은 현장사진과 동영상자료 혹은 레이져 스캐닝 데이터를 활용하여 사용자가 보다 높은 현실감과 몰입감을 느낄 수 있도록 함으로써, 의사결정에 소비되는 시간을 단축시킨다.