When oil spill disaster on sea takes place, the most effective measure is to use oil fence with vertical wall. It has been big challenges that suitable oil fence in consideration of variety of variables such as wind speed, height of wave and current direction is chosen. And current characteristics below two of vertical wall was studied by PIV experiment with utilizing technic of visualized analysis like velocity distribution, contour of velocity and streamline pattern in flow characteristic between vertical wall of oil fence. In this study it is purposed to identify characteristics of inside water flow between two vertical walls depending on respective various water speeds to minimize outflow of floating article below bottom of vertical wall and observed that re-circulation flow and irregular vortex at certain places between two vertical walls occurred. Consequently, the study showed that failure of oil fence such as entrainment failure and submergence failure can be largely lessen by means of optimizing length between two vertical walls with water speeds.

This study introduces a newly developed PC non-bearing wall system to prevent the damage of RC wall-type apartments that have been heavily damaged by the 2017 Pohang Earthquake. In order to evaluate the performance of the developed PC non-bearing wall system, a static cyclic test is conducted. The prototype of test specimen is from the RC wall-type apartment which has been severely damaged by the 2017 Pohang Earthquake. The specimen with the conventional non-bearing wall system showed the similar damage of RC wall type apartment suffered from the Pohang Earthquake. In case of the specimen with the developed PC non-bearing wall system, cracks and damages were not transmitted between the walls due to the seismic slit and there were almost no cracks in the non-bearing walls. Therefore, the proposed non-bearing wall system, separated from the structural walls, could prevent spreading cracks to bearing walls and make it possible to effectively control damage due to earthquake loads.

Background: The wall squat exercise has been recommended for strengthening of the lower extremity muscles with maintaining lumbar lordosis. Although squat has been studied to be related to lower extremity extensor strength, the relationship between wall squat and lower extremity extensor strength unclear. Because squat and wall squat are biomechanically different, study on the relationship is needed. Objects: The purpose of this study was to determine the lower extremity extensor strength associated with wall squat performance. Methods: 74 healthy volunteers were recruited to participate in this study. The volunteers were measured hip and knee extensors strength and then performed wall squat exercise for maximum count. Results: We found significant relationships between wall squat performance and hip extensor strength normalized by body weight, knee extensor strength normalized by body weight and the composite value. In a regression analysis, hip extensor strength normalized by body weight explained 29% of the variation in wall squat performance in males and 35% in females. Conclusion: These results demonstrate that hip extensor strength normalized by body weight is critical to wall squat performance in both sexes.

선박 및 수중구조물의 고속, 대형화 및 요구조건 강화의 추세에 따라 유동소음 예측기술의 중요성이 강조되고 있다. 항공, 철도 등의 공력소음 분야에서는 음향상사법을 이용하여 순음 및 광대역 유동소음에 대해 활발히 연구되고 있는 반면 조선해양분야에서는 수중추진기의 날개주파수소음에 대해서만 일부 고려되고 있다. 본 논문에서는 날개면 형상의 주요 유동소음발생 메커니즘 뒷날소음을 고려 가능한 FW-H Formulation 1B를 이용하여 수중추진기 및 선저부가물의 기초요소인 수중익에 대해 광대역소음 예측기법을 연구하였다. 기존의 FW-H Formulation 1B는 공기 중의 압력상관관계 모델에 기반하여 구성되어 있어 매질에 대한 일반성 및 정확도의 한계를 가지므로 수중환경에 대해 일반성을 가지는 벽면변동압력 모델로 확장하는 방법론을 제시하였다. 공기 중 날개면의 소음계측결과와 비교해 벽면변 동압력 모델을 이용할 경우 기존모델의 해석결과 대비 5 dB 이내의 오차로 정확도 관점에서의 유용성을 확인할 수 있었으며 전산유체역 학과 벽면변동압력을 이용한 수중환경의 광대역소음해석 절차를 확립하고 수중익의 광대역소음 예측을 수행하였다.

The traditional earth wall structure consists of a Joongkit(a small reinforcing post inside a wall) and a Oe(a miscellaneous tree, rendered laths) based on the space between the columns and applying the soil. The members who act as the base layer before applying soil used joongkit, sakmok, and oemok, which are known to correspond to the current joongkit, gasisae, and lath strips. This study was designed to understand the following through an analysis of the ancient texts, such as uigwe. Through a study on the usage and specifications of joongkit recorded on the uigwe, I wanted to reveal that joongkit is a material that has different specifications, functions, and installation techniques from current joongkit. The purpose of this study was to present the differences and technical features of the components of use for two types of oeyeokki technique of traditional wall. In addition, the items to be considered at the actual cultural heritage repair site were reviewed in the restoration of the earth wall weaving technique.

The flow characteristics around the vertical wall with the flap were visualized in the water channel using PIV. And the effect of flap angle change was investigated to see how quickly the spreading can be prevented and confined if oil spill occurs at sea. As a result, the fluid in the front of the vertical wall flows constantly, Nearing a boundary layer on the vertical wall, and a flow separation phenomenon occurs. Thereafter, flow loss or depth loss to the bottom of the vertical wall was confirmed. Also, it was observed that irregular reverse circulation flow occurred due to flap angle change and pressure gradient at the back of vertical wall. In this study, it was analyzed that it is most effective at 20 degrees angle. In the future, it is necessary to confine the flow characteristics of PIV and CFD by assuming that there is a double vertical wall in which oil having a lower specific gravity than water is trapped in the oil fence.

1950년대 이래 발굴하기 시작한 당 벽화묘는 대다수가 陝西關中의 西安市郊와 부근의 禮 泉縣, 乾縣, 長安縣, 三原縣, 富平縣과 咸陽市郊에 집중 분포한다. 山西 太原, 寧夏 高原, 新疆 吐魯番 등지에서도 당묘 벽화가 출토되었다. 당대는 중국 고분벽화의 발달에서 가장 전성기에 해당하나 고분 내의 벽화의 주제나 구성은 인물화 중심으로 주로 현실세계를 반영하여 비교적 단순하며 사신을 제외하고 천상세계의 묘사는 드문 편이다. 당묘는 또한 부장용의 수가 많고 종류가 다양하며 북조 도용보다 진전된 세련된 표현과 기법을 보여준다. 한대 곽거병묘에 시 초가 보이는 陵墓 神道의 조각상들은 남북조를 거쳐 당에 이르면 대형화․정형화한다. 본 논문은 영하 고원수당묘와 염지당묘를 사례로 선택하여 소그드의 昭武九姓 가운데 하나인 史氏姓과 何氏姓의 소그드묘장을 고찰하여 두 지역의 묘장의 구조와 벽화 제재, 부장품에 나타난 특징을 통하여 해당 시기의 묘장에 드러난 문화적 변용에 대해서 살펴보았다.

In this study, the results of an analytical investigation on the seismic behavior of two residential 4-story bearing wall buildings with pilotis, each of which has symmetric or unsymmetric wall arrangement at their piloti level, are presented. The dynamic characteristics and lateral resistance of the piloti buildings were investigated through linear elastic and nonlinear static analyses. According to the results, the analytical natural period of vibration of the piloti buildings were significantly shorter than the fundamental period calculated in accordance with KBC 2016. In the initial elastic behavior, the walls resisting in-plane shear contributed to the lateral stiffness and strength, while the contribution of columns resisting flexural moments in double curvature was limited. However, after the shear cracking and yielding of the walls occurred, the columns significantly contributed to the residual strength and ductility. Based on those investigations, design recommendations of low-rise bearing wall buildings with piloti configuration are given.

In 2017 Pohang Earthquake, a number of residential buildings with pilotis at their first level were severely damaged. In this study, the results of an analytical investigation on the seismic performance and structural damage of two bearing wall buildings with pilotis are presented. The vibration mode and lateral force-resisting mechanism of the buildings with vertical and plan irregularity were investigated through elastic analysis. Then, based on the investigations, methods of nonlinear modeling for walls and columns at the piloti level were proposed. By performing nonlinear static and dynamic analyses, structural damages of the walls and columns at the piloti level under 2017 Pohang Earthquake were predicted. The results show that the area and arrangement of walls in the piloti level significantly affected the seismic safety of the buildings. Initially, the lateral resistance of the piloti story was dominated mainly by the walls resisting in-plane shear. After shear cracking and yielding of the walls, the columns showing double-curvature flexural behavior contributed significantly to the residual strength and ductility.

초고층 건물의 횡변위 제어를 위하여 사용되는 아웃리거를 기존의 철골 트러스 대신에 철근콘크리트 벽체로 대체할 수 있다. 철근콘크리트 아웃리거 벽체를 외부 기둥에 연결할 경우에는 축력뿐만 아니라 전단력과 모멘트가 외부 기둥에 유발될 수 있다. 본 연구에서는 아웃리거 벽체 외단부의 회전으로 인한 외부 기둥의 전단력을 수식으로 유도하고 그 값을 유한요소해석 결과와 비교하였다. 유한요소해석에서는 층별 연결보의 효과와 전단벽과 아웃리거를 보와 평면응력요소로 모델링한 효과를 분석하였다. 층별 연결보의 효과는 거의 없었으며 평면응력요소는 보요소보다 더 큰 강성을 가진 것으로 해석되었다. 아웃리거 벽체의 외단부 회전으로 인한 외부기둥의 층간 회전각과 전단력은 허용값에 비하여 상당히 작은 값이 발생하였다. 따라서 초고층 건물에 철근콘크리트로 된 아웃리거 벽체를 적용할 경우에도 외부 기둥에 유발되는 전단력과 모멘트에 대하여 별도의 검토를 할 필요는 없을 것으로 판단된다.

본 연구는 지진에 저항하는 부재인 비보강 조적벽체로 구성된 건물의 내진성능평가에 활용되는 비선형 정적해석을 위한 비보강 조적벽체의 해석모델을 수립하고자 하였다. 본 연구의 해석모델은 비보강 조적벽체의 휨거동을 모사하기 위한 파이버 요소와 비보강 조적벽체의 전단에 대한 응답을 예측하기 위한 전단스프링 요소로 구성된다. 본 논문은 먼저 제안하고 있는 모델의 형상에 대해서 설명하고, 기존에 행해진 조적조 프리즘의 실험결과로부터 얻은 응력-변형률 곡선을 근거로 파이버와 전단스프링 요소의 물성치에 대한 결정 방법을 설명한다. 제시하고 있는 모델은 비선형 정적 해석결과와 다른 연구자들에 의해 수행된 실험결과를 비교하여 타당성을 검증한다. 해당 모델은 최대강도, 초기강성, 그리고 이들로부터 얻어지는 비보강 조적벽체의 하중-변위 곡선을 적절하게 모사하고 있다. 또한, 해석모델이 비보강 조적벽체의 파괴모드를 예측할 수 있는 것으로 나타난다.

This study aims to evaluate thermal performance using the ASTR method. Its findings are as follows: 1) The measured U-Values of 49A type and 59A type walls were almost the same as the theoretically calculated values. 2) One notable phenomenon for both walls was that the interior surface temperatures of the channels attached to corners were up to 10.4% lower than that of the cross of the wall, even though they consisted of the same materials. This is due to the surface temperature drop caused by the thermal bridge. 3) The surface temperatures of the thermal bridge were converted into U-Values. The U-Value of the top left corner on the 59A type house was 1.044W/m²K, and of the bottom right corner on the 49A type house was 0.959W/m²K. Therefore, the thermal performance of the thermal bridge area was decreased after construction. 4) Differences were found in the results of comparing heat transfer analysis simulation data and measured data. A maximum difference of 12.4% occurred in the top left corner on 59A type, and of 7.6% occurred in the bottom right corner on 49A type. 5) The results of a heat transfer analysis simulation showed that the temperature of both 49A type and 59A type top right corner were the lowest, but in-situ measurement results were the lowest in the bottom right corner on 49A type and in the top left corner on 59A type. These results are considered to be due to the occurrence of thermal bridges and a deterioration in the construction quality.

본 연구에서는 옹벽 구조물의 내진성능 평가를 위해 2차원 유한요소 해석을 수행하였다. 2차원 유한요소 모델은 실제로 시공된 옹벽 구조를 기반으로 2차원 평면변형 요소로 모델링되었으며, 지반은 각각 유한요소와 무한요소로 모델링 하였다. 지진하중은 총 38개의 인공 지진을 생성하여 사용하였고, 생성된 인공 지진파를 11개의 PGA로 나누어 총 418회의 시간이력해석을 수행하였다. 수치해석 결과를 바탕으로 옹벽 구조물의 지진에 대한 취약도를 분석하였다. 취약도 분석 결과 콘크리트 및 철근의 취약도 곡선이 낮은 PGA 수준에서 급격히 변하는 것을 관찰할 수 있었다. 유한요소 해석 결과를 바탕으로 실제 현장의 옹벽 구조에서 상대적으로 낮은 수준의 지진파가 발생하더라도 높은 파괴확률로 인해 지진에 상대적으로 취약함을 확인하였다.