• 한국전자파학회논문지
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• 제24권6호
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• pp.654-660
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• 2013

본 논문에서는 벽 뒤의 표적을 탐지하기 위한 영상화 기법을 연구한다. 벽에 의한 강한 반사 신호와 벽 뒤의 난반사 신호로부터 정확한 표적 정보를 획득하기 위해 잡음 신호를 이용하는 바이스태틱 벽 투과 영상 레이더의 연구 가능성을 제안하고, 획득 신호를 영상화하는 기법을 설명한다. 제안하는 연구의 도출 과정을 제시하며 실험 결과를 분석함으로써 제안하는 연구의 가능성을 검증한다.

• 한국지반신소재학회논문집
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• 제4권1호
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• pp.17-25
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• 2005

본 논문에서는 옹벽 시공 완료 후 여름철 집중강우로 인해 붕괴된 보강토 옹벽 사고사례에 대한 원인 분석을 실시하였다. 사고 원인의 명확한 규명을 위해 붕괴된 옹벽의 현장조사 및 실내시험, 현 설계법에 근거한 안정성평가, 강우의 침투해석 및 suction을 고려한 사면안정해석을 실시하였고, 그 결과 현장조건을 제대로 반영하지 못한 부적합한 설계와 불량한 뒤채움 흙의 사용, 단기간의 집중호우로 인한 suction의 감소 및 전단강도의 감소가 붕괴의 주원인인 것으로 나타났다.

• 설비공학논문집
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• 제19권11호
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• pp.782-788
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• 2007

In this paper, the freezing process of the water supply pipe in the exterior wall of an apartment house was analyzed by numerical method. The thickness of the pipe insulation and the percentage of insulation damage were considered as parameters in this paper. In the cases of the 0%, 8% and 20% damaged of the 5mm thickness insulation, the freezing was completed after 13 hours, 10 hours and 7 hours respectively. And in cases of the 10mm thickness insulation, the freezing was completed after 18 hours, 10.5 hours and 8 hours respectively. As a result, it is predicted that the water freezing would occurred when the water supply pipe with 8% or 20% damaged insulation are installed in the exterior wall. However, the water freezing would not occurred when the water supply pipe with 10mm thickness insulation of 0% damage is installed in the exterior wall.

• 지구물리
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• 제6권2호
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• pp.71-77
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• 2003

Generally the dynamic characteristics of stone wall structures depend on several factors such as contact, the type of interlocking bonding stones, and the filling materials. This paper describes a non-destructive technique for diagnosis of historic masonry stone structures using the measurement of natural frequency technique. For this purpose, the castle wall of Nag-An Folk Town located in Sunchon, Korea was selected as a model. The Nag-An Town Castle is one of the well maintained historical remains constructed in the Chosun Kingdom of Korea. The construction started in 1397 A.D and was finished in 1626 A.D. The non-mortar castle wall is 1470m long and the average height is 4m with a width of 3 4m. The exterior of the wall is bonded with 1 2 m rectangular rough-faced stone and the inside of the wall is filled with gravel. The traditional village still remains inside the Nag-An Town Castle, and they have a regional food festival every October. Transverse vibrations were measured at 8 points around the castle. The measured natural frequency of the first mode was 26Hz 41Hz, and the shear modulus of filling material was 2.142 x $10^3$ ~ 8.915 x $10^3$kgf/$cm^2$ . With these results, it may be assumed that the filling material is gravel or a sand-gravel mixture. It is expected that the information provided by this paper will be useful for addressing the maintenance problems of the old castle walls.

• 헤리티지:역사와 과학
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• 제33권
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• pp.68-92
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• 2000

This paper reconsiders the users of iron arrowheads from Mongchon Earthen Wall(夢村土城). Because the Mongchon Earthen Wall has been seen as a major dwelling fort of the Hansong Period(漢城時代 : 18 B.C.~475), Paekche(百濟), these iron arrowheads have been considered as artifacts of the Hansong Paekche with no systematic analysis since they were found in 1985. However, uncovering numerous Koguryo artifacts, the excavations in 1988 and 1989 showed that Koguryo(高句麗) army had occupied the Mongchon Earthen Wall after they had conquered Hansong Paekche. In this paper, focusing on the formal similarity between these arrowheads and those from other Koguryo sites, I attempt to reconsider the nature of arrowheads from the Mongchon Earthen Wall. Found from a small pit, all of these arrowheads (88 in number) seem to have been contemporaneous. While all are stemmed, they can be divided into nine types on the basis of the shape of body and point. Most types are equal or similar to Koguryo arrowheads of other regions, and especially type F and G have not been found in southern Korean Peninsula. Accordingly, it is suggested that the existing models be reconsidered, and that Koguryo army who had conquered Hansong Paekche used these arrowheads around mid-5th century AD. Although at this point it is difficult to determine the users of these arrowheads only by analyzing several formal attributes due to Korean archaeology's little understanding of the arrowheads of the Three Kingdoms Period(三國時代), I expect that application of natural scientific methods will contribute to a better understanding.

• International Journal of Naval Architecture and Ocean Engineering
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• 제12권1호
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• pp.1-10
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• 2020

This paper investigates the influence of the Circulating Water Channel (CWC) side wall and support struts on the hydrodynamic coefficient prediction for Autonomous Underwater Vehicles (AUVs) experiments. Computational Fluid Dynamics (CFD) method has been used to model the CWC tests. The hydrodynamic coefficients estimated by CFD are compared with the prediction of experiments to verify the accuracy of simulations. In order to study the effect of side wall on the hydrodynamic characteristics of the AUV in full scale captive model tests, this paper uses the CWC non-dimensional width parameters to quantify the correlation between the CWC width and hydrodynamic coefficients of the chosen model. The result shows that the hydrodynamic coefficients tend to be constant with the CWC width parameters increasing. Moreover, the side wall has a greater effect than the struts.

• Nuclear Engineering and Technology
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• 제54권9호
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• pp.3526-3539
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• 2022

Nuclear thermal-hydraulic system analysis codes have been developed to simulate nuclear reactor systems, which solve simplified governing equations by replacing source terms with constitutive relations for simulating entire reactor systems with low computational resources. For half a century, many efforts have been made for wider versatility and higher accuracy of system codes, but various factors can affect the code analysis results, and it was difficult to isolate these factors and interpret them individually. In this study, two system codes, RELAP5 and TRACE, which have many users and are highly reliable, are selected to analyze only the effects of constitutive relations. The influence of constitutive relations is analyzed using in-house platforms that replicate constitute relations of RELAP5 and TRACE equally to exclude factors that may affect analysis results, such as governing equation solvers and user effects. Among the various constitutive relations, the analysis is performed on the wall variables expected to have the most influence on the analysis results. Part 1 paper presents the methodology and wall friction model comparison, while Part 2 paper shows wall heat transfer comparison of the two selected codes.

• Steel and Composite Structures
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• 제24권1호
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• pp.1-13
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• 2017

In order to improve the deformation capacity of the high-strength concrete shear wall, five high-strength concrete shear wall specimens confined with high-strength rectangular spiral reinforcement (HRSR) possessing different parameters, were designed in this paper. One specimen was only adopted high-strength rectangular spiral hoops in embedded columns, the rest of the four specimens were used high-strength rectangular spiral hoops in embedded columns, and high-strength spiral horizontal distribution reinforcement were used in the wall body. Pseudo-static test were carried out on high-strength concrete shear wall specimens confined with HRSR, to study the influence of the factors of longitudinal reinforcement ratio, hoop reinforcement form and the spiral stirrups outer the wall on the failure modes, failure mechanism, ductility, hysteresis characteristics, stiffness degradation and energy dissipation capacity of the shear wall. Results showed that using HRSR as hoops and transverse reinforcements could restrain concrete, slow load carrying capacity degeneration, improve the load carrying capacity and ductility of shear walls; under the vertical force, seismic performance of the RC shear wall with high axial compression ratio can be significantly improved through plastic hinge area or the whole body of the shear wall equipped with outer HRSR.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1668-1672
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• 2005

This paper presents the wall following control of a small indoor airship (blimp). The purpose of the wall following control is that a blimp maintains its position and pose and flies along the wall. A blimp has great inertia and it is affected by temperature, atmospheric pressure, disturbance and air flow around blimp. In order to fly indoors, a volume of blimp should be small. The volume of a blimp becomes small then the buoyancy of a blimp should be smaller. Therefore, it is difficult to attach additional equipments on the blimp which are necessary to control blimp. For these reasons, it is difficult to control the pose and position of the blimp during the wall following. In our research, to cope with its defects, we developed new blimp. Generally, a blimp is controlled by using rudders and elevators, however our developed blimp has no rudders and elevators, and it has faster responses than general blimps. Our developed blimp is designed to smoothly follow the wall by using low-cost small ultra sonic sensors instead of high-cost sensors. Finally, the controller is designed to robustly control the pose and position of the blimp which could control in spite of arbitrary disturbance during the wall following, and the effectiveness of the controller is verified by experiment.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
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• pp.895-898
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• 2008

본 연구는 최근 국내의 옹벽 및 교대의 신기술 특허 등록 동향을 조사하여 파악하며, 이들 신기술특허를 적절히 실제 옹벽 및 교대 공사에 적용하려는데 목적을 두고 있다. 본 연구에서 조사된 신기술옹벽으로는 PS강봉에 프리스트레스를 도입한 단면력 저감형 조립식 PC옹벽공법, Coupler-Tension 조립식 옹벽, 도로용 블록식 보강토옹벽, 균등침하를 유도할 수 있는 블록식 보강토옹벽이 있으며, 신기술 교대로는 시트파일을 이용한 교대의 시공공법, 일체식 복합교대 교량, 반 일체식 교대교량의 시공방법, 보강토 교대구조를 기술하였다.