• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.343-358
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• 2008

Piles of a bridge pier are connected with a column through a pile cap(footing). Behavior of the pile foundation can be different according to the connection method between piles and the pile cap. This difference causes a change of the design method. Connection methods between pile heads and the pile cap are divided into two groups ; rigid connections and hinge connections. KHBDC(Korea Highway Bridge Design Code) has specified to use rigid connection method for the highway bridge. In the rigid connection method, maximum bending moment of a pile occurs at the pile head and this helps the pile to prevent the excessive displacement. Rigid methods are also good to improve the seismic performance. However some specifications prescribe that conservative results through investigations for both the fixed-head condition and the free-head condition should be reflected in the design. This statement may induce an over-estimated design for the bridge which have very good quality structures with casing covered drilled shafts and the PC-house contained pile cap. Because the assumption of free-head conditions (hinge connections) are unreal for the elevated pile cap system with multiple piles of the long span sea-crossing bridges. On the other hand, elastic displacement method to evaluate the pile reactions under the pile cap is not suitable for this type of bridges due to impractical assumptions. So, full modeling techniques which analyze the superstructure and the substructure simultaneously should be performed. Loads and stress state of the very large diameter drilled shaft and the pile cap for Incheon Bridge which will the longest bridge in Korea were investigated through the full modeling for rigid connection conditions.

• Journal of the Optical Society of Korea
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• 제19권5호
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• pp.508-513
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• 2015

A capacitive-type touch screen panel (TSP) composed of silver nanowire (AgNW) crossing electrodes and transparent bridge structures was fabricated on a polycarbonate film. The transparent bridge structure was formed with a stack of Al-doped ZnO (AZO) electrodes and SU-8 insulator. The stable and robust continuity of the bridge electrode over the bridge insulator was achieved by making the side-wall slope of the bridge insulator low and depositing the conformal AZO film with atomic layer deposition. With an extended exposure time of photolithography, the lower part of the SU-8 layer around the region uncovered by the photomask can be exposed enough to the UV light scattered from the substrate. This leads to the low side-wall slope of the bridge insulator. The fabricated TSP sample showed a large capacitance change of 22.71% between with and without touching. Our work supplies the technological clue for ensuring long-term reliability to the highly flexible and transparent TSP made by using conventional fabrication processes.

• 한국건축시공학회지
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• 제6권2호
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• pp.111-117
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• 2006

In case of carrying out vortical crossing water distribution system in expressways or general roads construction, VR(Vibrated and Rolled reinforced concrete) pipes are restricted because of their specification of reinforced spun concrete pipe or on-site made pipe. Therefore, in order to apply VR pipes to those constructions, through the structural behavior experiments of the pipes, VR pipes are compared and verified with reinforced spun concrete pipe and the results are obtained as the following. From the experiments and analyses of Pipe Stiffness(PS) of the pipes, cracking loading is approved to satisfy the KS regulations. Through a direct load test, the cracking loading strength and the maximum load test of VR pipe is larger compared with reinforced spun concrete pipe. Particularly, even if side weld is thin, there is no little change in the cracking strength of VR pipe. The results of the direct load test analysis show that the structural behavior of VR pipe is equivalent or higher compared with reinforced spun concrete pipe in performance and VR pipe could be used as the water distribution pipe for roads. In this study, through pipe stiffness, direct load test and load teat on earth, reinforced spun concrete pipe and VR pipe are compared. And as a result, the structural behavior of VR pipe is comprehensively excellent. From the structural behavior tests, VR pipe's section shows more thickness and has uniform characteristics so that VR pipe is considered more favorable than reinforced spun concrete pipe.

• 한국터널지하공간학회 논문집
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• 제16권4호
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• pp.373-386
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• 2014

본 연구에서는 연약대를 관통하는 터널의 변위거동에 관한 연구내용을 다루었다. 이를 위해 발파굴착 공법이 적용되는 터널을 대상으로 다양한 파쇄대 조건을 도출하고 이에 대한 3차원 해석을 수행하여 파쇄대의 주향 및 경사와 터널 변위 거동과의 관계에 대한 매개변수 연구를 실시하였다. 해석결과를 토대로 파쇄대의 공간적 분포 특성에 따른 터널의 파쇄대 관통 전후의 변위 거동을 고찰하였으며 이를 토대로 현재 실무에서 적용되고 있는 3차원 계측결과의 활용방안을 모색하였다. 3차원 해석 결과를 분석한 결과 터널 천단 및 내공변위의 각 성분비는 터널 주변 파쇄대의 터널과의 상대적 위치 및 방향성에 따라 달라지는 것으로 관찰되어 천단 및 내공변위 등 전통적인 터널 안정성 지표와 아울러 터널의 안정성 검토는 물론 주변 파쇄대 존재여부를 판정하는 지표로 활용할 수 있는 것으로 검토되었다.

• 한국항공운항학회지
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• 제31권2호
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• pp.89-94
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• 2023

Recently, domestic small airport development plans are being promoted centering on islands, and among them, Baengnyeong Island Airport is located very close to North Korea due to its geographical characteristics. In particular, since it is located in the P-518, which is prohibited airspace, it is essential to configure the arrival/departure flight procedure route similarly to the current ship in terms of securing flight safety. Therefore, in this study, a plan for airport location and facility scale was proposed by focusing on the runway operated for the purpose of aircraft operation through consultations with the Ministry of National Defense. It was proposed to meet the standards of the Airport Facility Act as an airport dedicated to domestic flights for airside facilities such as runway length and direction, target aircraft, landing pad, apron, runway and taxiway width appropriate for the topographical characteristics of Baengnyeong Island. As a result, the flight procedure is generally established as a two-way visual flight, but the 10-way arrival/departure procedure was planned to be changed to an instrument (non-precision) according to the specificity of the region. In addition, a flight procedure was established and presented for safe and systematic operation by reflecting the changes in airport facility size (landing pad, runway end safety area, etc.) following the change in instrument flight procedure in the visual flight procedure.

• Current Optics and Photonics
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• 제3권2호
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• pp.143-149
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• 2019

Shape ellipticity dependence of the exciton fine energy levels in CdTe and CdSe nanocrystal quantum dots were compared theoretically by considering the crystal structure and the Coulomb interaction of an electron and a hole. While quantum dot ellipticity changes from an oblate to prolate quantum dot via spherical shape, both the fine energy levels and the dipole moment in wurtzite structure of a CdSe quantum dot change linearly for ellipticity. In contrast, CdTe quantum dots were found to show a level crossing between the bright and dark exciton states with a significant change of the dipole moment due to the cubic structure. Shape ellipticity dependence of the optical nonlinearities in CdTe and CdSe nanocrystal quantum dots was also calculated by using semiconductor Bloch equations. For a spherical shape quantum dot, only $1^L$ dominates the optical nonlinearities in a CdSe quantum dot, but both $1^U$ and $0^U$ contribute in a CdTe quantum dot. As excitation pulse area becomes strong (${\sim}{\pi}$), the optical nonlinearities of both CdSe and CdTe quantum dots are mainly governed by absorption saturation. However, in the case of a prolate CdTe quantum dot, the real part of the nonlinear refractive index becomes relatively significant.

• 선박안전
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• 통권38호
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• pp.69-77
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• 2015

If we don't know the intention of altering course of a target ship when being in a head-on or a crossing situation, we may be confused about our decision making to change our course for collision avoidance and be in a danger of collision. In order to solve these problems, we need to develop an automatic detection system on altering course of a target ship for efficient collision avoidance. In this paper, we proposed an early detection system on altering course of a target ship using the steering wheel signal. This system will contribute to the reduction of collision accidents and also be used to the VTS system and the analysis of marine accidents.

• 대한수학회보
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• 제55권1호
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• pp.239-250
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• 2018

A knot complement admits a pseudo-hyperbolic structure by solving Thurston's gluing equations for an octahedral decomposition. It is known that a solution to these equations can be described in terms of region variables, also called w-variables. In this paper, we consider the case when pinched octahedra appear as a boundary parabolic solution in this decomposition. The w-solution with pinched octahedra induces a solution for a new knot obtained by changing the crossing or inserting a tangle at the pinched place. We discuss this phenomenon with corresponding holonomy representations and give some examples including ones obtained from connected sum.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 1998년도 추계 학술대회논문집
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• pp.204-210
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• 1998

A method is developed to include the effect of volume expansion in the description of the flame dynamics using G-equation. Line volume-source is used to represent the effect of the exothermic process of combustion with source strength determined by the density difference between the burned and the unburned region. Volume expansion adjusts the flow field to accommodate the increased volume flow rate crossing the flame front. Test result predicted the measured velocity field qualitatively. The method was applied to study the interaction of vortex and premixed flame. Increased volume expansion did not change the initial growth rate of flame area. However, the residence time and flame surface area increased with higher expansion ratios.

• 천문학회보
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• 제43권1호
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• pp.71.3-71.3
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• 2018

Asteroids represent a significant resource for space exploration and scientific research. Various scientific missions have already performed and planned to investigate and understand the characteristics of asteroids. This talk introduces many space missions to asteroids. Representing missions to asteroids are the NASA's NEAR, Deep Space-1, Dawn, OSIRIS-Rex, SCOUT, DART, and ESA's Rosetta, and JAXA's Hayabusa 1 and 2, and DESTINY+ missions, and others. Although it is a very rare event, the possibility of Earth-crossing asteroids (ECAs) colliding with the Earth can never also be ignored. Numerous mitigation concepts also have been proposed to deflect ECAs in preparing for the disasters which might occur in future days. In the early studies for mitigation schemes, most of analyses were centered on to deflect ECAs with impacting the energy to the object to change its orbit. This talk also introduces many methods to deflect the orbit of ECAs, and shows spacecraft trajectories to asteroids.