• Journal of Broadcast Engineering
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• v.13 no.2
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• pp.236-244
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• 2008

We propose a new building detection and description algorithm for Lidar data and photogrammetric imagery using color segmentation, line segments matching, perceptual grouping. Our algorithm consists of two steps. In the first step, from the initial building regions extracted from Lidar data and the color segmentation results from the photogrammetric imagery, we extract coarse building boundaries based on the Lidar results with split and merge technique from aerial imagery. In the secondstep, we extract precise building boundaries based on coarse building boundaries and edges from aerial imagery using line segments matching and perceptual grouping. The contribution of this algorithm is that color information in photogrammetric imagery is used to complement collapsed building boundaries obtained by Lidar. Moreover, linearity of the edges and construction of closed roof form are used to reflect the characteristic of man-made object. Experimental results on multisensor data demonstrate that the proposed algorithm produces more accurate and reliable results than Lidar sensor.

• Fire Science and Engineering
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• v.23 no.6
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• pp.135-141
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• 2009

The composite truss has been widely used for tall buildings and long-span structures in North America. As compared with other similar structures, it has merits such as reduction of construction period, low span/depth ratio, low dead weight and so on. It has the most effective trait for structures with long span of 12~18m. After collapse of WTC, the fire resistance behaviors of structures have been actively conducted under various fire conditions in several country. This study showed that the surface temperature of steel member in the composit truss beam was reached to $700^{\circ}C$ under the fire condition of a short time. Under the same condition, the temperature in concrete was within $200^{\circ}C$. The composit truss beam with 20mm bracing was collapsed by rapid deflection after about 3minutes. However, the beams with 25mm, 35mm, and 45mm bracing were not collapsed, even though those were reached to deflection standard of L/20 within 15minutes.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.30 no.3
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• pp.114-122
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• 2018

This paper introduces a non-hydrostatic wave model SWASH for simulating wave interactions with porous structures. This model calculates the flow in porous media based on volume-averaged Reynolds-averaged Navier-Stokes equations (VARANS) in ${\sigma}$-coordinate. The empirical coefficients of resistance used to account for the flow in a porous media often need to be measured or calibrated. In this study, the empirical resistance coefficients used in the model are calibrated and validated using laboratory experiments, involving dam-break flow through porous media, and solitary wave interactions with a porous structure. It is shown that the agreement between experimental and numerical results is generally satisfactory. It is also confirmed that non-hydrodynamic model, SWASH, is computationally much more efficient than the three-dimensional porous flow models based on VOF approach.

• Journal of the Earthquake Engineering Society of Korea
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• v.15 no.4
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• pp.13-21
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• 2011

Seismic structure pounding between adjacent superstructures may induce the destruction of pier and bridge superstructures and cause local damage that leads to the collapse of the whole bridge system. The pounding problem is related to the expansion of joints, gap distance and seismic response of the abutments. In this research, methods of the contact element approach, the linear spring model, the Kelvin-Voigt model and the Hertz model were studied to analyse the pounding characteristics. The shaking table test for a model specimen such as a bridge superstructure with elastomeric bearings was performed to evaluate the contact element approach methods. Relationships between the time history response from the numerical analysis results and the measured response from the shaking table test are compared. The experimental results were not well matched with the numerical analysis results using the existing pounding stiffness models. Therefore, in this study, coefficients are proposed to calculate the appropriate pounding stiffness ratio.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.33 no.3
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• pp.110-121
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• 2021

The importance of tidal flats lost due to industrialization has recently received attention, and attention is being paid to the creation of artificial tidal flats and maintenance of natural tidal flats. However, there is still a lack of understanding about the behavioral characteristics of mud, mud, and sand that form tidal flats. Although research on the movement characteristics of mixed soils such as tidal flats has been conducted through field investigations and hydraulic experiments, interest in developing a numerical model based on these results has not yet reached. In this paper, the purpose of this paper is to establish a mixed soil model that can efficiently manage the low quality of the tidal flats. In constructing a model for reproducing the surface movement of mixed soil, the numerical stability of the reproduction and movement of sand and mud constituting the mixed soil in the numerical model should be considered first, so first, the volume of sand and mud constituting the mixed soil A mixed soil model representing the relationship was proposed based on a topographical diagram representing the geometric structure of the mixed soil. In order to consider the dry bulk density of the mixed soil, it was possible to consider the dry bulk density of the mud by introducing the water content of the mud containing water. In addition, it was confirmed that the mud and sand movement calculation according to the slope collapse of the mixed soil was stably performed through the calculation of the slope collapse of the mixed soil through the numerical analysis model to which the proposed mixed soil model was applied.

• Journal of the Earthquake Engineering Society of Korea
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• v.14 no.5
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• pp.13-22
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• 2010

Masonry infill walls are frequently used as interior partitions and exterior walls in low- or middle- rise RC buildings. In the design and assessment of buildings, the infill walls are usually treated as non-structural elements and they are ignored in analytical models because they are assumed to be beneficial to the structural responses. Therefore, their influences on the structural response are ignored. In the case of buildings constructed in the USA in highly seismic regions, infill walls have a lower strength and stiffness than the boundary frames or they are separated from the boundary frames. Thus, the previously mentioned assumptions may be reasonable. However, these systems are not usually employed in most other countries. Therefore, the differences in the seismic behaviors of RC buildings with/without masonry infill walls, which are ignored in structural design, need to be investigated. In this study, structural analyses were performed for a masonry infilled low-rise RC moment-resisting frame. The infill walls were modeled as equivalent diagonal struts. The seismic behaviors of the RC moment-resisting frame with/without masonry infill walls were evaluated. From the analytical results, masonry infill walls can increase the global strength and stiffness of a structure. Consequently, the interstory drift ratio will decrease but seismic forces applied to the structure will increase more than the design seismic load because the natural period of the structure decreases. Partial damage of the infill walls by the floor causes vertical irregularity of the strength and stiffness.

• Proceedings of the Korea Technology Innovation Society Conference
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• 2011.06a
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• pp.134-149
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• 2011

최근 제약 및 바이오 분야는 국내 외 환경변화로 인해 역동적인 모습을 보이고 있다. 국내외 매출규모 상위 제약회사(국외 10개, 국내 11개 기업)와 유망 바이오회사(국외 8개, 국내 7개 기업)를 분석해본 결과, 기존과 다른 혁신적인 모습이 관찰되었다. 즉 제약 및 바이오 분야 기업들의 기존 블록버스터 비즈니스 모델은 관련 특허가 곧 만료됨에 따라 붕괴되고, 새로운 신약개발을 위해 치열한 경쟁이 시작되어 새로운 차원의 비즈니스 모델이 구상되고 있다. 따라서 새로운 형태로 생명공학계와 제약 산업 간의 '협업' 및 '분업' 구조가 나타나게 되었으며, 이는 오픈 이노베이션이라는 개념과 함께 구체화되고 있다. 본 연구에서는 '91~'11년 동안의 제약 및 바이오 분야의 기술혁신 패턴과정을 Utterback & Abernathy의 시계열적 기술혁신 패턴의 개념으로 설명하고, 특허 전문 DB인 Thomson Reuters사의 Aureka를 활용하여 약 20년 동안의 주요 제약 및 바이오 기업들의 R&D 분야 변화 및 융합되는 모습 등을 분석하였다. 또한, 각 종 시장분석자료를 재종합하여 관련 기업의 M&A 및 라이센싱 규모를 파악하고, 더 나아가 새롭게 등장한 바이오-파마(Bio-Pharma)의 오픈 이노베이션의 유형을 분석하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10a
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• pp.448-450
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• 2004

센서 네트워크는 다양한 탐지 대상 및 환경을 감시하는데 유용하게 사용될 수 있다 이러한 센서 네트워크에서 센서 노드간 키를 설립하는 것은 보안을 위한 가장 기본적인 요구 사항이다 하지만 센서가 가진 기본 특성인 자원의 제약 때문에 일반 네트워크에서 사용되고 있는 중앙 키 분배 서버를 이용한 키 분배나 공개키 기법을 사용하는 것은 적합하지 않다. 따라서 본 논문에서는 센서 네트워크 특성에 맞는 키의 사전 분배 방식을 제안한다. 본 논문에서 제시한 기법은 클러스터를 기반으로 위치 정보를 이용하여 키를 사전 분배하였기 때문 에 노드간 키 설립확률을 높였을 뿐만 아니라, 악의적인 노드에 의해 다항식이 공개되어 정상 노드가 붕괴되는 것을 막기 위해 클러스터당 헤드를 두어 다항식을 공유하는 노드의 범위를 줄여 보안을 보다 강화 시켰다.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.484-484
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• 2017

최근 홍수 시 제방붕괴로 인한 인명 및 재산피해가 증가되고 있어 노후화된 제방 시설물의 안전관리 체계에 대한 필요성으로 국토교통부에서는 국가하천유지보수 종합체계 시스템을 개발하였으나 아직 시범단계로 실무에 적용하여 활용하고 있지 못한 실정이다. 효율적인 국가하천시설에 대한 유지관리를 위한 자료D/B화 및 관리대장, 점검기법, 보수보기법 등을 제시하고 있으나 국가하천에 국한되어 있어 전국단위 하천시설물의 전주기에 대한 통합적인 관리는 반영되어 있지 못하다. 하천시설물 생애주기관리를 위해서는 모든 하천시설물에 대한 이력관리가 필요하나 현재는 시설물의 안전관리에 관한 특별법(시특법) 상의 1, 2종 시설물에 대해서만 시설물정보관리종합시스템(FMS)에서 이력관리를 수행하고 있는 실정이다. 따라서 본 연구에서는 국가하천 및 지방하천에 대한 하천시설물의 생애주기 관리방안을 도출하기 위해 기존의 시스템의 기능 및 구조를 분석하였으며 이를 통해 하천시설물 생애주기 관리방안을 제시하였다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.2
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• pp.104-112
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• 2012

The failure of tenon in a traditional wood-framed structure may collapse of the entire structure. This study evaluates the strength and stiffness of tenon joints between the beams and pillars through experimental study and suggests reinforcing method of the tenon joint without dismantling the main structures. The main experimental parameters are the number, distance, shape, and inserting depth of spiral-shaped reinforcing steels. As the thickness of the tenon in beams increases, the strength and the initial shear stiffness of the joint increases and, however, the tenons in pillar becomes weaker, resulting in the safety problem of the structure. It is recommended that three spiral-shaped reinforcing steels be placed in the central parts of the tenon to effectively improve the strength and the shear stiffness of the joint.