This study investigated the seismic performance of reinforced concrete (RC) wall-slab frames with masonry infills. Four RC wall-slab frames with or without masonry infill were tested under cyclic loading. The RC frames were composed of in-plane and out-of-plane walls and top and bottom slabs. For masonry infill walls, cement bricks were stacked applying mortar paste only at the bed joints, and, at the top, a gap of 50 mm was intentionally left between the masonry wall and top RC slab. Both sides of the masonry walls were finished by applying ordinary or fiber-reinforced mortars. The tests showed that despite the gap on top of the masonry walls, the strength and stiffness of the infilled frames were significantly increased and were different depending on the direction of loading and the finishing mortars. During repeated loading, the masonry walls underwent horizontal and diagonal cracking and corner crushing/spalling, showing a rocking mode inside the RC wall-slab frame. Interestingly, this rocking mode delayed loss of strength, and as a result, the ductility of the infilled frames increased to the same level as the bare frame. The interaction of masonry infill and adjacent RC walls, depending on the direction of loading, was further investigated based on test observations.

본 연구는 인공지능 연구개발과정에 많은 인적자원이 필요함을 인지하고 현 개발방식 고려할 사항에 대해 논의한다. 결론적으로 인공지능 개발의 효율성 향상을 위해서는 소수의 관리자와 많은 일반작업자들의 분업화가 이루어져야 가능하며, 이는 마치 일종의 경공업의 형태와 유사하다고 생각된다. 따라서 본 연구진은 컴퓨터라는 기계장치로 데이터라는 디지털 자원을 다루어 생산의 효율성 을 높이는 인공지능 개발과정을 4차산업시대의 디지털 경공업이라고 명명한다. 이전 산업혁명시대에서 경험한 것과 마찬가지로 인 적자원을 효율적으로 배분화하고 활용한다면 디지털 경공업은 2차산업혁명 못 지 않는 발전을 기대할 수 있을 것이며, 이를 위한 인 력양성이 시급하다고 판단된다.

In this study, the effectiveness of a multi-action hybrid damper (MHD) composed of lead rubber bearing (LRB) and friction pad was verified in terms of seismic performance improvement of a frame structure. The LRB and the friction elements are connected in series, so the LRB governs the intial small deformation and the friction determines large deformation behavior. Cyclic loading tests were conducted by using a half scale steel frame structure with the MHD, and the results indicated that the structure became to have the stable trilinear hysteresis with large initial stiffness and first yielding due to the LRB, and the second yielding due to the friction. The MHD could significantly increase the energy dissipation capacity of the structure and the hysteresis curves obtained by tests were almost identical to the analytically estimated ones.

Full-scale seismic retrofit of old and deteriorated masonry buildings requires a lot of cost and time. In such buildings, installing an emergency evacuation space can be considered as an alternative. In this study, requirements of the earthquake-proof table used as an emergency evacuation space for buildings hit by earthquake are investigated. Load conditions required for the table, including the impact effects due to building debris drop, are explained. To investigate the impact effects in more detail, weight drop test is performed for an prototype earthquake-proof table. In the test, the weight of the falling object and free fall height were considered as the main test parameters. The results showed that the duration of impact is very short (0.0226~0.0779sec), and thus the impact forces increase to 15.8~45.2 times the weight of the falling object. Based on these results, design considerations and performance verification criteria of the earthquake-proof table as an emergency evacuation space are given.

본 연구는 모아레 현상을 이용하여 구조물의 평면부재의 변형을 탐지하는 방식을 개발하였다. 평행선형상인 기존연구와 비교하여 본 연구의 원형형상은 변형 시 고유한 무늬가 나타나 변형의 방향도 시각적으로 인지할 수 있었다. 또한 변형을 확실하고 자동 으로 구분할 수 있도록 기계학습의 이미지분류를 사용하여 탐지한 결과 이미지 표면이 오염되더라도 KNN, SVM방식으로는 95%의 인식률, AlexNet과 Gogglenet Inception으로는 99%의 인식률을 보여 실현장활용이 가능할 것으로 판단된다.

본 연구에서는 마찰력에 따른 TMD의 작동-정지조건과 각 조건에 따른 운동방정식을 정리하고, TMD의 마찰계수가 풍진동 제어성능에 미치는 영향을 수치해석을 통하여 확인하였다. 일반적인 하중과 달리 풍하중은 크기와 방향의 변화가 크기 때문에 TMD 는 마찰력에 의하여 작동-정지상태를 반복하게 되므로, TMD의 마찰계수를 주요 변수로 설정하였다. 또한 외부하중의 크기, 구조물의 진동수, TMD의 질량비도 매개변수로 설정하여 TMD의 제진성능에 대한 영향을 파악하고자 하였다. 자유진동, 조화강제진동, 풍진동에 대한 수치해석의 결과, 외부하중의 크기가 작고, 구조물의 진동수가 낮을수록 마찰계수에 의한 TMD의 제진성능의 손실이 커질 수 있음을 확인하였으며, 초고층 건물에 대한 TMD 설계시 마찰계수의 영향을 반드시 고려하여야 할 것으로 판단된다.

본 논문에서는 실제 공연장을 예제 건물로 하여 공연장에 발생한 진동을 측정한 결과를 바탕으로 공연장 구조물의 안전성에 대해 해석적으로 평가하였다. 수치해석 프로그램은 MIDAS GEN을 사용하였으며, 바닥판은 합성효과를 고려하여 모델링 하였다. 해석결과 진동계측실험을 통해 구한 바닥판 고유진동수와 유사한 결과를 보였다. 또한 군중의 율동에 의한 동적하중을 시간이력해석으로 해석하여 진동계측 실험과 유사한 수준의 바닥판 가속도 응답을 확인하였다. 이 모델을 사용하여 예제 공연장의 최대관람인원인 400명의 집단율동 시 발생하는 상황에 대하여 분석하였다. 그 결과 기둥과 보의 가해지는 외력은 설계 내력을 하회하여 안전성에 문제없음을 확인하였다. 또한 공연 시 발생하는 수평방향 진동수준은 지진하중의 2% 수준으로 수직수평 모두 안전성에 문제가 없는 것을 확인하였다.

본 연구에서는 초고층건축물의 풍진동 모니터링을 위한 시스템식별기법의 현장적용성을 평가하였다. 실제 아웃리거-벨트월 을 횡력저항 시스템으로 가지는 실제 63층 RC구조물을 대상으로 상시 및 강풍시 응답을 모니터링하였으며, 진동수영역분해(FDD), 랜덤감소(RDT)기법, 부분공간시스템식별(SSI)법을 사용하여 진동특성을 식별하였다. 건물의 평면이 정방형이고, 두 개의 횡방향 모드의 진동수는 매우 유사하였다. 모든 식별기법에서 태풍과 같이 강한 외력이 존재할 경우 뿐만 아니라 상시미진동 에서도 구조물의 모드 특성을 식별할 수 있었다. 현장에서의 적용성 평가결과, 계산속도는 FDD가 가장 빨랐으며, RDT가 가장 간단한 프로그래밍 절차를 가지고 있음을 확인하였다.

이 연구에서는 RTK-GPS 장비를 사용하여 상시바람하중 및 가진 진동 실험시 계측된 변위 응답을 이용하여 실물크기 5층 철골 프레임에 대한 시스템식별 실험을 수행하였으며, 그 결과를 가속도 응답을 사용하여 얻은 결과와 비교하였다. RTK-GPS는 10Hz의 비교적 낮은 샘플링 속도를 가지고 있어 현장상황을 고려하여 적절한 측정안정도를 확보하는 것이 중요하였다. 변위자료를 사용하여 식별된 모드특성은 가속도 자료를 사용하여 얻은 것과 동일하였으며, 가속도계를 사용하여 측정할 수 없는 변위응답의 평균성분을 관측할 수 있었다.

Mineral filler is used for resin compounds, because it increases the stiffness and thermal stability of a resin compound, and it also cuts down the cost. Calcium carbonate, silica, magnesium oxide, and others are used as filler materials in general, and the type of filler material, the size, and content can affect the physical properties of compounds. Those factors also influence the viscosity of resin mixtures and the workability, and should be adjusted by changing the contents of the filler, which depends on the size. In this study, five kinds of ground calcium carbonate, which were different in size, were used to produce polyester compounds ; the physical properties were compared with the filler size and contents. The mechanical properties were measured by bending strength and tensile strength, and the heat deflection temperature was obtained for thermal stability.

In this paper, a new waffle-shaped(WAS) precast concrete panel was developed through the geometrical modification of the conventional double tee panel. It is a one-way joisted panel with a shallow depth and a boxed shape by wide edge beams. To investigate the structural performance of the connections between W AS panels, loading tests called by WIW were performed at the connections along short edges of two WAS panels. WIW tests were executed according to two different width of shear key(50mm and 80mm) and three types of reinforced topping concrete(wire-mesh alone, wire-mesh plus HD 10, and wire-mesh plus HD13). As a result, the grouting width of shear keys did not act on the ultimate behaviors significantly, and the flexural strength of WIW connections along the long edges of W AS panels was superior to nominal flexural strength. The connections with proper details of steel reinforcement can distribute the positive bending moment at mid-span of W AS panels to the negative moment, which is useful for efficient member design.

In order to obtain the flexural and shear performance capacity of newly developed WAffle Slab(WAS) System, 14 full-scale 1.98mx10.00m specimens were tested under monotonic load. The Flexural performance was observed and compared with the conventional double-tee slab system using the test result. The shear performance was observed W AS slab using the test result. lt was confirmed that WAS system has enough flexural and shea capacity to carry the design load. Destruction features of test result, it appeared with bending destruction on the whole. According to steel wire increase, tolerance force's also increased. But steel wire increases to follow, it appears brittle destruction aspect. Case of shear test, the stirrup interval to be narrow maximum load appeares the tendency which comes to be destroyed.

In-Sit반응소결에의해 Si과 AI금속분말을 이용하여 Si3N4-AIN 복합세라믹스를 합성하였다. 합성된 Si3N4-AIN복합세라믹스의 미세조직과 결정구조를 해석하기 위해, OM, TEM, XRD및 EDX를 이용하였으며, Si3N4-AIN -20wt.%AIN복합세라믹스에서 Si의 질화율은 97%로 가장 높았다. Si3N4-AIN 복합세라믹스에서 Si의 질화율은 AI첨가량 증가에 따라 감소하였다. 대부분의 AI입자들은 다결정 AI입자들은 다결정 AIN(4-H구조)로 완전질화되었으며, 따라서 잔류 AI상은 반응소결체내에서 관찰되지 않았다. Si3N4의 결정구조는 α와 β구조가 혼재된 상태이며, 잔류 Si입자내에서는 미소균열 및 전위가 관찰되었다. AI/Si3N4와 Si3N4 두계면에서 이들은 거친 형상을 보이지만, 계면반응상은 관찰되지 않았다.

This study is the result of the survey on perception and anxiety of high - rise buildings in the general public. As a result of the survey, there was insufficient change in awareness before the construction of high - rise buildings such as landmarks was insufficient (before 2015). However, half of the citizens who felt uneasy that high-rise buildings were likely to collapse due to external influences were close. The anxiety was mainly due to the information of the press or the Internet. It is thought that the cause of anxiety comes from touching negative opinions about the high-rise buildings.

In modern society, people spend most of their time on various types of chairs. However, it is not easy for a designer to design a comfortable chair because satisfaction with the chair depends not only on the quantitative elements such as size, but also on the qualitative element such as the user’s feeling. To deal with these problems, there have been many studies on designing ergonomic chairs. This paper proposes the haptic-aided design (HAD) system to design an ergonomic chair. Based on the HAD system, the designer can experience whether the chair is comfortable or not through the haptic device, and also can modify the design parameters instantaneously. The haptic chair capable of controlling the design parameters in real time was proposed as a haptic simulator. The controllable parameters, such as seat height, reclining angle, stiffness of the backrest, and so on were selected based on the previous research related to ergonomic chairs. The proposed methodology will help reduce the development cost and time by replacing the process of making the real mock-ups and prototypes with the haptic chair.

In an information-oriented society, visually impaired persons also should obtain the information with relative ease. They tend to receive the information of letters by tactile sensation through braille display systems. Several types of braille display systems have been suggested so far, but none of them have been widely used yet. The braille display system should provide multiple lines of braille units to improve the level of understanding. In this paper, we propose a cell type braille unit with 3x2 dots, each of which consists of a piezoelectric linear motor. A braille cell is small and lightweight enough to be portable, and it can be easily assembled in multiple lines. The preliminary tests using the proposed braille display system show that it can provide the information that can be well perceived by visually impaired persons.