• 한국공간정보시스템학회:학술대회논문집
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• 2005.11a
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• pp.23-28
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• 2005

고해상도 위성영상으로부터 건물, 도로 등의 인공지물의 정보를 추출하기 위한 연구들이 현재 활발히 진행되고 있다. 대부분의 기존 연구들의 경우, 위성영상에서 3차원 건물정보를 추출하기 위해서는 영상과 별도의 기준점을 필요로 하며, 영상에서의 측정값을 3차원 정보로 변환하기 위해서는 센서모델링의 과정을 거쳐야 했다. 이 연구에서는 단안식 (Monoscopic)영상으로부터 이러한 복잡한 과정을 거치지 않고 직접 건물의 3차원 정보를 추출하는 기술개발에 대하여 소개한다. 제안하는 방식은 단안식 영상에서 영상의 방위각 및 촬영지역에서의 태양과 카메라의 방위각 및 고도각을 이용하여 건물의 높이가 주어졌을 때 이에 따르는 건물 수직선과 건물 그림자를 영상에 투영시키는 과정을 반복함으로써 투영된 건물 그림자가 실제 영상에서 관측되는 건물의 그림자와 일치될 대의 건물의 높이 값을 구하고 건물 지붕 외각선을 구해진 건물의 높이 값에 따르는 건물 수식선 만큼 수평 이동하여 건물의 위치를 구하게 된다. 실제 대전지역을 촬영한 IKONS 영상을 이용하여 실험한 결과 이와 같은 방법으로 취득 된 건물 높이값이 약 1m 내외의 정확도를 가지는 것을 나타났다.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.948-954
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• 2004

This study deals with the Evaluation of track system, when Newly developed Korea High Speed Train(KHST) by KRRI and KTX trains are running pass curved track of conventional line. In order to evaluate stability of track and vehicle running safety. the effect of curve radius, the field tests were performed at sharply curved track.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1993.10a
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• pp.93-97
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• 1993

방진고무는 진동을 방지하여 다른 구조물의 진동전달 차단은 물론, 장비의 수명연장 및 효율을 증가시키기 위한 목적으로 사용되는데 이러한 방진고무 의 동적특성을 일반화하는 것은 어렵기 때문에 방진고무 시편의 동특성 해 석시험 결과치를 기준으로 원하는 성능에 부합하도록 방진고무의 재질을 선 정하고 사양에 의한 엔진마운트를 설계 제작하여야 한다. 이번에 제작한 UEM 엔진마운트는 해상용, 육상용 설비에 적용 가능하며, 특히 해상용에 적 용하고 외부 환경에 의한 부식으로부터 방진고무 및 기자재를 보호하기 위 하여 하우징을 특수재질로 제작하였고, 수직.수평력을 고려하여 큰 하중에 견딜 수 있도록 원추형 형상설계와 강성을 보강하였다. 특히, 원추형 형상으 로 제작하여 하중을 일정하게 분산시키고, 사용 가능한 선형영역을 확대 시 켰으며, Buffer(Steel Bar)를 이용하여 높은 파고 등에 의한 외부 충격량에 따른 큰 변위의 발생으로부터 설비를 보호할 수 있다. 본 논문에서는 물리적 특성이 같은 방진고무를 사용하고, 적층 수만 다르도록 두가지 모델 UEM-155와 UEM-255를 설계 제작하여 수직.수평방향의 정적시험, 동적시 험, 현장 장착시험 등을 수행함으로써 기업에서 요구한 사양에 적합한가를 고찰하였다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.4D
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• pp.579-586
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• 2008

In this study, it was evaluated that the 3D tracking accuracy of basketball zone track line by real time GNSS satellite positioning methods which are VRS (Virtual Reference System), DGPS (Marine Differential GPS) and PP (Point Positioning) methods. The results of comparison between three methods over horizontal track of basketball zone, VRS, DGPS and PP methods showed ${\pm}$ several cm, ${\pm}$ m, and ${\pm}$ 2m horizontal position accuracy compared with real size respectively. And also, the grade and height deviation of the checking points on basketball zone by VRS method is very similar to the real grade and height, but results by DGPS and PP methods showed big variation and deviation in each case. We expected that VRS method using GNSS reference network will be a very useful tool compared with single based RTK method in real time accurate positioning such as precision construction fields, especially.

• Journal of the Korea Concrete Institute
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• v.27 no.5
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• pp.501-510
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• 2015

Composite construction of precast concrete and cast-in-place concrete is currently used for the modular construction. In this case, the use of steel fiber reinforced concrete (SFRC) could be beneficial for precast concrete. However, the shear strength of such composite members (SFRC and cast-in-place concrete) is not clearly defined in current design codes. In the present study, steel fiber composite beam tests were conducted to evaluate the effect of steel fibers on the composite members. The test variables are the area ratio of SFRC and shear reinforcement ratio. The test results showed that when minimum horizontal shear reinforcement was used, the shear strength of composite beams increased in proportion to the area ratio of steel fiber reinforced concrete. However, because of the steel fiber, the composite beams were susceptible to horizontal shear failure. Thus, minimum horizontal shear reinforcement is required for SFRC composite beams.

• Journal of the Korean Society for Railway
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• v.19 no.4
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• pp.480-488
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• 2016

For the development of areas around railway lines, subsurface construction using the non-open cut method under the railway has recently been increased. However, when a structure under a railway is constructed, the stress release of the ground is not considered an important factor in the design. In this study, laboratory tests were conducted to determine a zone of stress relaxation. Field tests using an inclinometer were performed to measure the horizontal displacement of the ground during non-open cut construction. The stress release zone and the subgrade stiffness were investigated by numerical analysis. The results of the laboratory tests indicated that the failure zone in the ground was similar to a Rankine's active earth pressure zone. The measured data from the inclinometer in the field tests showed that displacements started when a steel pipe was pushed into the ground. The results of numerical analysis show that lateral earth pressure was also close to Rankine's active earth pressure. The roadbed support stiffness of the soil around the structure decreased to 40% of the original value. The ground around the subsurface structure constructed using nonopen cut methods should be reinforced to maintain the running stability of train.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.26-32
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• 2019

The purpose of this study is to improve the running speed on a small-radius curved section on an existing train line. When the transition curve was extended, and the amount of movement in the horizontal direction tended to increase as the curve radius increased. The amount of increase in the transition curve extension was lowest when extending the curve radius, and the amount of horizontal movement was the lowest when changing the curve radius to a cosinusoidal curve. As a result of applying the pass rate after improvement to the Kyeongbu line, there was a time-shortening effect of 9.4 to 11.6% and a facial expression speed increasing effect when the curve radius was fixed and the transition curve was changed to a sinusoidal curve. In conclusion, the most effective way to improve the running speed on an existing train route is to change the image to concrete and to change the relaxation curve to a cosinusoidal curve. The amount of horizontal movement of the track is small, and the speed improvement effect is excellent.

• The korean journal of orthodontics
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• v.25 no.1 s.48
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• pp.13-18
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• 1995

Craniofacial asymmetry was analyzed in 39 patients with complete unilateral cleft lip and palate(UCLP). The samples are devided into three groups nine below 9 years, twenty three from 9 years 1 month to 14 years and seven over 14 years group. Seventeen measurements were obtained from the tracing of PA X-ray cephalometric headfilms to evaluate the asymmetric characteristics and changes accdording to aging in UCLP. The obtained results were as follows. 1. Facial asymmetry in UCLP is variable(1.22-3.47 $mm/^{\circ}$) and the length from midsagitta1 reference line to maxillary 1st molar, to upper central incisor and the length of mandibular ramus showed significant asymmetry 2. Nasal septum and anterior nasal spine were deviated In the cleft side and the lower border of nasal cavity was 1ower in cleft side. 3. The deviation of nasal septum was continued significantly till after 14 years old.

• Journal of Dental Rehabilitation and Applied Science
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• v.24 no.2
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• pp.183-192
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• 2008

Modern dental reconstructions do not only aim at restoring the patient's mastication, but rather at improving general well-being and quality of life, especially in terms of esthetics. The media, the internet, advertising, and many other facts of society contribute to an increased cosmetic awareness. A 35-year-old male patient presented with as follows: 1) the porcelain fracture of ceramo-metal restoration on #11 and #23, 2) the inclination of incisal plane to horizontal reference plane, 3) the dental midline deviation to facial midline, and 4) the lack of symmetry on upper anterior dentition. The patient requested an aesthetic improvement using fixed prosthodontics including implant-supported restorations. In the upper anterior region, one of the goals of the conventional as well as implant prosthesis is to achieve restorations with the dental attractiveness and beauty in the respect of dental, dentofacial, and facial compositions. This case report presents geometrically improvement of dental esthetics using conventional and implant prosthesis with soft and hard tissue augmentation.

• Geophysics and Geophysical Exploration
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• v.25 no.4
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• pp.189-200
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• 2022

Ground subsidence on urban roads is a social issue that can lead to human and property damages. Therefore, it is crucial to detect underground cavities in advance and repair them. Underground cavity detection is mainly performed using ground penetrating radar (GPR) surveys. This process is time-consuming, as a massive amount of GPR data needs to be interpreted, and the results vary depending on the skills and subjectivity of experts. To address these problems, researchers have studied automation and quantification techniques for GPR data interpretation, and recent studies have focused on deep learning-based interpretation techniques. In this study, we described a hyperbolic event detection process based on deep learning for GPR data interpretation. To demonstrate this process, we implemented a series of algorithms introduced in the preexisting research step by step. First, a deep learning-based YOLOv3 object detection model was applied to automatically detect hyperbolic signals. Subsequently, only hyperbolic signals were extracted using the column-connection clustering (C3) algorithm. Finally, the horizontal locations of the underground cavities were determined using regression analysis. The hyperbolic event detection using the YOLOv3 object detection technique achieved 84% precision and a recall score of 92% based on AP50. The predicted horizontal locations of the four underground cavities were approximately 0.12 ~ 0.36 m away from their actual locations. Thus, we confirmed that the existing deep learning-based interpretation technique is reliable with regard to detecting the hyperbolic patterns indicating underground cavities.