The equivalent static load for non-structural elements has a limitation in that the sloshing effect and the interaction between the fluid and the water tank cannot be considered. In this study, the equations to evaluate the impulse and convective components in the design codes and previous research were compared with the shaking table test results of a rectangular water tank with flexible wall panels. The conclusions of this study can be summarized as follows: (1) It was observed that the natural periods of the impulsive component according to ACI 350.3 were longer than system identification results. Thus, ACI 350.3 may underestimate the earthquake load in the case of water tanks with flexible walls. (2) In the case of water tanks with flexible walls, the side walls deform due to bending of the front and back walls. When such three-dimensional fluid-structure interaction was included, the natural period of the impulsive component became similar to the experimental results. (3) When a detailed finite element (FE) model of the water tank was unavailable, the assumption   could be used, resulting in a reasonably conservative design earthquake load.

Existing reinforced concrete buildings with seismically deficient details have premature failure under earthquake loads. The fiber-reinforced polymer column jacket enhances the lateral resisting capacities with additional confining pressures. This paper aims to quantify the retrofit effect varying the confinement and stiffness-related parameters under three earthquake scenarios and establish the retrofit strategy. The retrofit effects were estimated by comparing energy demands between non-retrofitted and retrofitted conditions. The retrofit design parameters are determined considering seismic hazard levels to maximize the retrofit effects. The critical parameters of the retrofit system were determined by the confinement-related parameters at moderate and high seismic levels and the stiffness-related parameters at low seismic levels.

이 연구는 일본 규슈 북쪽 서단(西端)에 위치한 작은 도시지만, 제1,2 차 세계대전에서 구(舊)일본 해군의 군사적 요충지 역할을 맡은 군항도시 사세보(佐世保)가 관광도시로 전환되는 그 과정의 설계와 실천 과정에 기반을 두고 있다. 1983년 개장한 나가사키(長崎) ‘오란다무라(Holland Village)’는 지역경제에 많은 파급효과를 가져왔고, 1992년 개장한 ‘하우 스텐보스(Huis Ten Bosch)’는 관광도시로의 전환에 있어 ‘결정체’와 같 은 역할을 했다. 오랜 기간 군항도시의 역할이 지속된 사세보는 전전기 (戦前期)와 전후기(戦後期)를 거치며 어두운 전쟁의 체험과 역사적 흔적 을 남겼다. 하지만 사세보 시민들이 염원하던 ‘평화산업항만도시’로의 전 환에 있어 결정체 역할을 한 ‘하우스텐보스’의 개장은 마치 어두운 전쟁 의 역사의 흔적을 지우듯 나가사키의 역사와 문화라는 옷을 입혀 그 부 지위에 자리 잡았다. 하우스텐보스가 조성된 부지는 전전기에는 해군병 교 하리오(針尾)분교가, 전후기에는 인양자들의 숙소이자 인양 원호국이 자리잡고 있었던 곳이었다. 이처럼 사세보의 어두운 역사의 땅 위에 하 우스텐보스가 지어지며 군항도시에서 관광도시로 전환된 과정을 흥미롭 게 살펴보고자 한다.

With the advancement of optical design and manufacturing technology, optical components have found diverse applications, spanning from semiconductors to the aerospace industry. A reflective mirror is a basic component in optics and plays a crucial role as the medium to reflect light. In this paper, a large mirror with a 700mm diameter was designed as a primary mirror using fused silica. The rear side of the mirror was subdivided into several equal angles, and neighboring vertices on the circumference were connected to establish a polygon. Accordingly, the geometric shapes of triangle, square, pentagon, and hexagon were formed. Furthermore, the mirror structure was strengthened by employing straight lines passing the vertices and the center of the circle. Based on the finite element analysis, deformations of the mirrors caused by the gravitational force were evaluated. Weight and deformation of the mirror structures were compared and analyzed to find a proper structure to reduce weight and deformation. This paper, therefore, presents a structural solution aimed at reducing the weight and deformation of a large aperture mirror induced by gravitational forces, thereby suggesting a geometric shape based structure to reduce surface deformation of a mirror.

Recently, many countries are performing researchs about weapon systems or communication systems using laser. Because laser weapons are relatively easy to use and can exert powerful energy with high efficiency versus cost. Also laser communication systems has many advantages compared to RF communication systems, such as big data transmission through giga-bit communication, high security and so on. In these systems, one of highly important key components is Fast Steering Mirror(FSM) to control the laser beam precisely and accurately. Therefore, in this paper, we perform static and dynamic analysis to predict performances of Fast Steering Mirror using voice coil actuators. Also we manufacture prototype of FSM on the basis of static and dynamic analysis results, and perform the performance test about four items. As a result, we lay a foundation for research about FSM and laser systems, and expact to contribute improvement of performances of systems using laser.

In this study, In this study, structural analysis of a fuel tank for an SUV (sports utility vehicle) was performed for crack prevention design. Reservoir tank analysis was conducted for crack prevention design, and improvement measures for weak areas were discovered and reflected in the design. Pressure analysis was performed on the existing model to analyze weak areas. As a result of analysis through various design changes, it was found that the strength problem of the reservoir tank was due to the discontinuity of the rib inside the tank, and to improve this, it was necessary to minimize the discontinuity section.

In general, a large mirror without weight reduction in large optical or space telescope systems can increase the system’s weight or lead to significant deformation of the mirror surface. Thus, it is imperative to pursue lightweight design strategies. In this paper, the structure design of a spherical mirror, a diameter of 600mm and a mirror radius of 2,000mm, was investigated to reduce weight and minimize deformation. To establish load paths for internal and external loads, stiffeners were added across the lateral supports. This approach effectively reduced both weight and deformation caused by gravity. Weight reduction and reduction percentages were quantified, and the mirror deformation was evaluated by using finite element analysis (FEA). The proposed structures were compared with honeycomb structures for weight reduction. This evaluation allowed to assess the deformation characteristics and the potential advantages of the proposed structures for lightweight mirrors.

챗GPT는 학술 논문 요약, 프로그래밍 코드 작성, 수학 문제 해결, 발 표 자료 생성, 기사 작성 등 다양한 용도로 활용되고 있다. 국내에서도 신문기사 작성이나 학생들의 글쓰기 수업에서 챗GPT가 활용될 때 가짜 뉴스 양산이나 표절 등의 우려가 커지고 있다. 미국 대학들은 학생들의 챗GPT 사용 문제에 대응하는 방법을 모색하고 교육 방식을 개선하고 있 다. 본 연구의 목적은 대학 교양 철학 수업에서 챗GPT와 같은 인공지능 을 활용하기 위한 구체적인 수업 설계와 수업 활동을 제시하고자 한다. 이를 위해 각 주차 별로 철학 윤리적 주제를 5개 이상 선정하였고 각 주 제별로 학습자들이 조별 활동, 챗GPT 활용과 글쓰기를 통해 비판적으로 사고하고 철학적인 주제를 쉽게 이해할 수 있도록 학습자 참여 중심의 수업을 진행하였다. 또한 챗GPT를 활용한 이런 수업방식에 대해 11개 항목으로 구분하여 설문조사를 실시하였다. 그 결과 학습자들은 모든 항 목에 있어서 챗GPT를 활용하는 측면이 자신의 글쓰기 효용감과 수업의 이해도, 만족도 등을 높이는데 80% 이상 긍정적이라고 답하였다. 물론 챗GPT가 가짜 정보의 생성이나 인간의 사고력을 약화시킬 수 있다는 우 려가 있으나, 교수자가 수업 설계에 이런 부분을 보완한다면 신속하게 전체적으로 철학적 글쓰기의 틀을 구성하고 수업 내용을 보강하는데 긍 정적인 효과가 있는 것으로 나타났다. 따라서 인공지능을 적극적으로 활 용하여 철학교육을 위한 다양한 수업 설계를 위해 노력할 필요가 있다.