The goal of this study is to investigate structural behaviors of steel diagrid depending on geometric parameters such as size, thickness, steel type, and location of components. Numerical applications verify structural behaviors of steel diagrid is very sensitive in terms of the geometric parameters and then diagrid is an appropriately governing system for free-formed structures.

산화아연은 뛰어난 자외선 산란효과로 인해 자외선 차단 화장품에 널리 이용되고 있다. 최근 화장품용으로 쓰이는 산화아연은 자외선 차단 특성, 사용감, 광촉매 활성 저하, 분산성 및 안정성 등을 보다 우수하게 하기 위해 이산화규소 등의 물질로 표면처리 하는 방법이 시행되어지고 있다. 본 연구에서는 광 노화의 원인인 자외선을 차단하는 이산화규소가 코팅된 산화아연 복합 분체를 개발하였다. 화장품 업계에서 일반적으로 쓰이는 마이크로 크기의 산화아연에 사용감, 자외선 차단 특성을 보다 우수하게 하기 위해 산업적인 용도로 많이 쓰이는 규산나트륨을 사용하여 코팅하였다. 이산화규소를 코팅하기 위해 규산나트륨과 산의 가수분해 반응에 의한 수열합성법을 적용하였다. 제조된 복합 분체의 자외선 차단 효과는 UV-Vis과 in-vitro 측정을 통하여 평가하였다. 또한 화장품에 실제 적용 하였을 때의 실질적인 장점을 확인하기 위해 사용자 관능 평가를 통해 비교분석 하였다.

The goal of this study is to investigate an evaluated aerial work flatform for structure maintenance and repair. This study includes technical components and economic aspect. The investigation is extend and helpful to accomplish successful business according to foreign and domestic business.

The newly-developed self-mobilizing space frame system is the equipment possible to adjust frame width and height per various road tunnel sizes. Main purpose of this system is to maintain road tunnels without blocking lanes. Therefore, it does not affect traffic and completes maintenance work quickly as compared to current method.

Girder type and slab type modular bridges require using UHSC(Ultra High Strength Concrete) and high performance mortar to connect each girder and slab modules at joint parts. This study presents the results of mock-up tests on the properties of UHSC and high performance mortar for modular bridge

As numbers of tunnel are increased, the necessity of temporary maintenance works of those tunnels is also increased. This study introduces new space truss frame system for the maintenace of tunnels. Proto-type model was analyzed and evaluated. The result shows that new system may contribute to save the maintenance cost and time.

In this study, long term simulations for current(1979-2010) and future(2019-2050) climate over North-East Asian region were performed using RegCM4 driven by HadGEM2-AO provided by the KMA(Korean Meteorological Administration). The spatial resolution is 12.5㎞ and two RCP scenarios(4.5, 8.5) are applied for the future climate simulation. The RegCM4 simulates well the spatial and temporal variations of air temperature of current climate. However, it weakly simulates the intensity of rain band associated with the seasonal march of the East Asian summer monsoon and thereby significantly under simulates the summer rainfall and fails in reproducing the seasonal and spatial variations of precipitation. The 20-year averaged differences between current(1986-2005) and future(2031-2050) simulations showed that the temperature increases are generally greater in RCP8.5(1.93K) than RCP4.5(1.86K) and all the changes are statistically significant at 1% level. In general, the temperature increases are greater in the northern region(autumn, winter) than in the southern region(spring, summer) irrespective of RCP scenarios. The temperature over South Korea is expected to increase by 1.53K to 1.87K irrespective of RCP scenarios and seasons. The precipitation changes vary significantly according to the season and region irrespective of RCP scenarios and the changes of spring and autumn in the certain regions are statistically significant at 5% level. The precipitation over South Korea is expected to increase by +0.42㎜/day in RCP4.5 during spring but it is expected to significantly decrease during autumn(-0.35㎜/day) and in RCP 8.5 during summer(-0.30㎜/day).

본 연구는 터널의 유지, 보수, 보강에 필요한 가설공사용 스페이스 트러스 프레임 구조물을 소개한다. 기존 가설공사 시공방식과 장비들의 현황 및 문제점을 분석하고, 터널 설계의 핵심 구성요소를 파악함으로써, 제안된 새로운 가설 시공기술 시스템을 개발하는 과정을 순차적으로 설명한다. 그리고 개발된 가설 시스템을 발주처, 시공사, 터널 이용자 관점에서 사용성 및 경제성을 분석하고, 구조적인 안전성 검토와 최적단면 산정 평가를 상용 유한요소 해석프로그램인 ABAQUS 6.5로 구현하여 본 가설 시스템의 현장적용 기반을 구축한다.

민감도 해석은 구조 모델링 변수의 변화에 따른 역학적인 거동의 특성을 찾는 것을 목적으로 한다. 따라서 건물의 구조 진단과 보수 보강 분야에서 특히 중요한 설계 자료로서 활용되고 있다. 본 연구는 구조물의 위상학적 최적 모델링에서 중요하게 다루어지는 민감도 해석을 다양한 방법을 사용하여 공식화하였다. 감차법과 변분법을 적용하여 직접법과 수반법으로서 최종적인 해석적인 민감도 식들을 유도하였다. 구조 해석에 관한 간단한 수치예제를 통하여 유도된 민감도 식들의 해가 적절함을 수치적인 민감도 해석치와 비교하여 검증하였고, 최종적으로 이산화 민감도 해석에 의한 밀도분배법의 위상학적 최적 모델링을 수행하여 민감도 공식들을 위상 최적화 문제에서 정식화하였다.

This study examines whether the reinforcement theory would be effectively applied to teaching assistant robots between a robot and a student in the same way as it is applied to teaching methods between a teacher and a student. Participants interact with a teaching assistant robot in a 3 (types of robots: positive reinforcement vs. negative reinforcement vs. both reinforcements) by 2 (types of participants: honor students vs. backward students), within-subject experiment. Three different types of robots, such as ‘Ching-chan-ee’ which gives ‘positive reinforcement’, ‘Um-bul-ee’ which gives ‘negative reinforcement’, and ‘Sang-bul-ee’ which gives both ‘positive and negative reinforcement’ are designed based on the reinforcement theory and the token reinforcement system. Participants’ task performance and reaction rate are measured according to the types of robots and the types of participants. In task performance, the negative reinforcement robot is more effective than the other two types, but regarding the number of stimulus, the less the stimulus is, the more effective the task performance is. Also, participants showed the highest reaction rate on the negative reinforcement robot which implies that the negative reinforcement robot is most effective to motivate students. The findings demonstrate that the participants perceive the teaching assistant robot not as a toy but as a teaching assistant and the reinforcement interaction is important and effective for teaching assistant robots to motivate students. The results of this study can be implicated as an effective guideline to interaction design of teaching assistant robots.