• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2002.11a
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• pp.249-256
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• 2002

구조물의 안전성 평가와 수명예측은 구조물 내 결함에 관한 정확한 정보 즉, 결함의 종류, 크기, 위치, 형상으로 평가하고 있다 이들 결함의 분석과 해석 방법으로 실시간 평가가 가능하고, 구조물에 손상을 주지 않는 비파괴 결함 평가 방법이 널리 활용되고 있다. 특히 방사선투과시험에 의한 결함 해석과 평가는 투과사진 상에 나타나는 결함의 상으로부터 결함 형상과 결함 길이는 직접 확인할 수 있으며, 결함 깊이와 결함 높이의 해석에는 입체방사선투과검사법(Stereo-radiography)과 parallax법 등으로 현재 결함 깊이와 높이를 해석하고 있으나, 이러한 방법은 결함 검출을 위하여 조사방향을 여러방향으로 하여 방사선 투과사진을 다수 촬영하여야 하고, 촬영된 결함의 분석과 해석에도 숙련된 평가 기법이 요구되는 등 많은 문제점을 내포하고 있다.(중략)

• Korean Journal of Materials Research
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• v.8 no.9
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• pp.825-830
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• 1998

자화된 유도결합형 C4F8 플라즈마로 SiO2를 건식식각시 실리콘 표면에 발생하는 손상과 오염에 대하여 연구하였다. 오염의 분석을 위해서 XPS, SIMS, TEM을 사용하였으며, 손상정도를 측정하기 위해서 HRTEM과 Schottky-diode 구성을 통한 I-V특성 측정을 사용하였다. 유도 결합형 C4F8 플라스마에 0에서 18Gauss까지의 자장이 가해짐에 따라서 실리콘 표면에 생기는 잔류막의 두께가 SiO2식각속도와 선택비의 증가와 함께 증가하였으며, XPS를 통하여 그 조성이 fluorine-rich에서 carbon-rich 한 상태로 변화함을 알 수 있었다. 자장을 가하지 않는 상태에서는 표면에서 $40\AA$부근까지 고밀도의 손상층이 관찰되었으나, 자장을 가함에 따라서 노출된 손상층의 깊이는 깊어지나 그 밀도는 줄어들음을 HRTEM을 통하여 관찰 할 수 있었다. Schottky-diode를 통한 I-V특성곡선의 분석으로 자장이 증가함에 따라서 전기적인 손상이 감소함을 알 수 있었다.

• Journal of the Society of Naval Architects of Korea
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• v.48 no.1
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• pp.33-41
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• 2011

For the assessment of ultimate longitudinal strengths of damaged hull girders, it is preliminarily necessary to determine the extents and locations of the damages due to severe accidents. This paper deals with the estimation of the damages from collisions and groundings of large-sized vessels where deterministic and probabilistic approaches are investigated. Deterministic damages estimated from MARPOL(or ICLL), ABS and DNV are compared with probabilistic damages from IMO guideline and some references including damage statistic data. Damages from MARPOL show largest one among all the investigated damage estimation, since it was developed not for the residual strength of hull girder but for the damage stability calculation. IMO guideline with high level probability of damage(eg. 95% probability level) also forecasts even severer damage extents than MARPOL. On the other hand, assuming average probability level of damage, the calculated damage sizes are around the one from deterministic approaches.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.12
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• pp.2530-2538
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• 2015

The pixel value of depth image is depth value so that different objects which are placed on nearby position have similar pixel value. Moreover, the pixels of depth image have distinct pixel values compared to adjacent pixels while those of color image has very similar values. Accordingly distorted depth image of multiview video plus depth (MVD) needs proper error concealment methods considering the characteristics of depth image when transmission errors are happened. In this paper, classifying regions of depth image to consider edge directions and then applying adaptive error concealment methods to each region are proposed. Recovered depth images utilize with multiview video data to synthesize intermediate-view point video. The synthesized view is evaluated by objective quality metrics to demonstrate proposed method performance.

• Journal of the Korean Society for Nondestructive Testing
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• v.27 no.2
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• pp.164-172
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• 2007

Surface cracks in concrete are common defects that can cause significant deterioration and failure of concrete structures. Therefore, the early detection, assessment, and repair of the cracks in concrete are very important for the structural health. Among studies for crack depth assessment, self-calibrating surface wave transmission method seems to be a promising nondestructive technique, though it is still difficult in determination of the crack depth due to the variation of the experimentally obtained transmission functions. In this paper, the spectral energy transmission method is proposed for the crack depth estimation in concrete structures. To verify this method, an experimental study was carried out on a concrete slab with various surface-opening crack depths. Finally, effectiveness of the proposed method is validated by comparing the conventional time-of-flight and cutting frequency based methods. The results show an excellent potential as a practical and reliable in-situ nondestructive method for the crack depth estimation in concrete structures.

• Electronics and Telecommunications Trends
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• v.3 no.2
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• pp.37-56
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• 1988

ECR 플라즈마는 활성도가 크고 지향성이 강한 고에너지 빔으로서, 고속.고정밀.고 선택비의 식각공정과, 저온.저손상.고 평탄화의 증착공정, 3차원 구조에도 불순물을 원하는 깊이만큼 도우핑할 수 있는 불순물 주입공정 등에 폭넓게 응용될 수 있다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.3
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• pp.187-200
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• 2023

This study analyzed the seismic fragility of bored tunnels based on their surrounding conditions and suggested a representative seismic fragility model. By analyzing the existed seismic fragility models developed for bored tunnels, we developed weighted combination models for each surrounding conditions, such as ground conditions and depth of the tunnel. The seismic fragility curves use the peak ground acceleration (PGA) as a parameter. When the PGA was 0.3 g, the probability of damage exceeding minor or slight damage was 20% for depth of 50 m or less, 10% for depth between 50 m and 100 m, and 3% for depth of 100 m or more. It was also found that the probability of damage was higher for the same PGA and depth when the surrounding ground was rock rather than soil. The probability of damage decreases as the depth increase. This study is expected to be used for developing a comprehensive seismic fragility function for tunnels in the future.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.180-183
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• 2011

본 논문에서는 HEVC(High Efficiency Video Coding) 부호화기에서 사용되는 TU(Transform Unit) 분할이 깊이에 따라 속도와 화질과 압축률에 미치는 영향을 분석한다. 현재 HD 영상의 표준 부호화기로 사용되던 H.264/AVC 를 대신할 차세대 부호화기인 HEVC 에 대한 표준화 작업이 이루어지고 있으며 이러한 HEVC 부호화기의 특징 중 하나로 영상 압축 시 CU, PU, TU 로 세분화 된 단위를 사용한다는 점을 들 수 있다. HEVC의 reference software 인 HM 의 경우 기존 H.264/AVC 에 비하여 UHD 영상에서 최대 40%에 가까운 비트 절감률을 보이지만 최적화가 이루어지지 않아 실시간 부호화에는 적합하지 않은 속도를 보인다. HM 에서는 각 CU 나 TU 에 대하여 quadtree 형식으로 분할하여 부호화를 수행한 후 최적의 분할 형태를 취하는 방식을 사용하기 때문에 많은 시간을 소요하게 되며 분할되는 깊이에 비례하여 기하급수적으로 속도가 느려지게 된다. 본 논문에서는 TU 가 분할되는 깊이가 부호화 화질과 속도에 어느 정도 영향을 미치는지를 분석하고 화질 손상을 최소화 하는 최적의 TU 분할 깊이를 제안하여 보기로 한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.7
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• pp.1428-1436
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• 2012

This paper presents the delta image composition methods using Depth-Image-Based Rendering (DIBR) for 3D stereoscopic broadcasting for the low bandwidth mobile DMB broadcasting system. With DIBR, a left and depth images are transmitted to a mobile device, which restores the right view, whose quality may be poor. This paper describes delta image composition methods for the restoration while minimizing the amount of the transmitted data.

• Journal of the Society of Disaster Information
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• v.15 no.4
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• pp.479-492
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• 2019

Purpose: The purpose of this study is to accurately analyze the damage of bridges in order to determine whether fire bridges can be used continuously or to provide information on maintenance augmentation data. Method: XRD, SEM and EDS analyzes of concrete were carried out to estimate the fire temperature transferred to the structure, and analyzed by depth and area from PSCI beam and bottom plate concrete surface. Results: Test results G_12,11 for the fire zone concrete were confirmed to be affected by heat up to depth of 60mm and the temperature of the hydrothermal heat was above 1000℃. Also, the girder G_10,9,8 was relatively weakly damaged compared to G_12,11, and the degree of damage was confirmed to be affected by heat up to a depth of 40 mm. Conclusion: Based on the analyzed data, it is considered that if the repair / reinforcement and periodic inspection are carried out, the bridge can secure sufficient safety even considering the damage caused by the fire.