Machine learning is widely applied to various engineering fields. In structural engineering area, machine learning is generally used to predict structural responses of building structures. The aging deterioration of reinforced concrete structure affects its structural behavior. Therefore, the aging deterioration of R.C. structure should be consider to exactly predict seismic responses of the structure. In this study, the machine learning based seismic response prediction model was developed. To this end, four machine learning algorithms were employed and prediction performance of each algorithm was compared. A 3-story coupled shear wall structure was selected as an example structure for numerical simulation. Artificial ground motions were generated based on domestic site characteristics. Elastic modulus, damping ratio and density were changed to considering concrete degradation due to chloride penetration and carbonation, etc. Various intensity measures were used input parameters of the training database. Performance evaluation was performed using metrics like root mean square error, mean square error, mean absolute error, and coefficient of determination. The optimization of hyperparameters was achieved through k-fold cross-validation and grid search techniques. The analysis results show that neural networks and extreme gradient boosting algorithms present good prediction performance.

In this study, we propose an optimal design method by applying the Prefabricated Buckling Restrained Brace (PF-BRB) to structures with asymmetrically rigidity plan. As a result of the PF-BRB optimal design of a structure with an asymmetrically rigidity plan, it can be seen that the reduction effect of dynamic response is greater in the case of arrangement considering the asymmetric distribution of stiffness (Asym) than in the case of arrangement in the form of a symmetric distribution (Sym), especially It was confirmed that at an eccentricity rate of 20%, the total amount of reinforced PF-BRBs was also small. As a result of analyzing the dynamic response characteristics according to the change in eccentricity of the asymmetrically rigidity plan, the distribution of the reinforced PF-BRB showed that the larger the eccentricity, the greater the amount of damper distribution around the eccentric position. Additionally, when comparing the analysis models with an eccentricity rate of 20% and an eccentricity rate of 12%, the response reduction ratio of the 20% eccentricity rate was found to be large.

The cultural heritage of fortresses is often exposed to external elements, leading to significant damage from stone weathering and natural disasters. However, due to the nature of cultural heritage, dismantling and restoration are often impractical. Therefore, the stability of fortress cultural heritage was evaluated through non-destructive testing. The durability of masonry cultural heritages is greatly influenced by the physical characteristics of the back-fille material. Dynamic characteristics were assessed, and endoscopy was used to inspect internal fillings. Additionally, a finite element analysis model was developed considering the surrounding ground through elastic wave exploration. The analysis showed that the loss of internal fillings in the target cultural heritage site could lead to further deformation in the future, emphasizing the need for careful observation.

This study aims to investigate the seismic response of a large span thin shell structures and assess their displacement under seismic loads. The study employs finite element analysis to model a thin shell structure subjected to seismic excitation. The analysis includes eigenvalue analysis and time history analysis to evaluate the natural frequencies and displacement response of the structure under seismic loads. The findings show that the seismic response of the large span thin shell structure is highly dependent on the frequency content of the seismic excitation. The eigenvalue analysis reveals that the tenth mode of vibration of the structure corresponds to a large-span mode. The time history analysis further demonstrates, with 5% damping, that the displacement response of the structure at the critical node number 4920 increases with increasing seismic intensity, reaching a maximum displacement of 49.87mm at 3.615 seconds. Nevertheless, the maximum displacement is well below the allowable limit of the thin shell. The results of this study provide insight into the behaviour of complex large span thin shell structures as elevated foundations for buildings under seismic excitation, based on the displacement contours on different modes of eigenvalues. The findings suggest that the displacement response of the structure is significant for this new application of thin shell, and it is recommended to enhance the critical displacement area in the next design phase to align with the findings of this study to resist the seismic impact.

주요 선진국들은 저출산 및 고령화에 따른 인구구조 변화로 인해 중장 기적으로 노동시장의 변화를 겪고 있다. 해당 시장들은 인력공급제약 심 화를 겪으며, 경제 전반 성장률 저하 우려하고 있다. 노동인구 확보의 주 요한 대안으로 외국인력 유치가 부각되고 있으며, 이에 주요국들은 이민 정책을 통해 사회구조 변화에 대응하고 있다. 본 논문에서는 일본의 인 구구조 변화 및 경제현황, 이에 대응한 최근 이민정책의 변화를 분석하 였다. 일본은 첫째, 이민정책 도입 과정에서 배타적 정책방향성을 띤 차 별·배제 모형을 지향했다는 점, 둘째, 1950~1960년대 선진경제를 형성하 였으나, 특정 시기마다 저기술 노동력을 집단으로 유입할 수 있는 계기 가 발생하였으며, 2000년대 이후 급격한 노동력 부족과 인구구조의 변화 가 발생하였다는 점, 셋째, 일본은 한국과 유사하게 OECD 국가 중 제조 업이 강조되는 경제 구조를 띠고 있어, 경제적 측면에서 국제노동력 유 입이 필수적이라는 점의 특징이 있다. 이에 본 논문이 제시한 일본 이민 정책의 역할 분석은 한국 이민정책에 시사점을 주며, 정책방향성을 제시 할 수 있다.

본 연구목적은 청소년의 사회적 지지(부모자녀관계, 교사관계, 친구관 계)는 자기주도학습에 영향을 미치는지에 대한 확인과 자아존중감의 매개 효과를 규명하는 것이다. 경상북도교육청연구원에서 추진한 「경북교육종 단연구」의 2023년 12월 예비조사에서의 중·고등학생 청소년 360명을 연 구대상자로 선정하였으며, SPSS 26.0, Stata 16.0 및 Smart-PLS 3.0을 활용하여, 빈도분석, 기술통계, 상관관계분석 및 구조방정식모델 분석을 수행하였다. 첫째, 청소년의 부모자녀관계는 자아존중감 및 자기주도학습 에 유의한 정적 영향을 미쳤다. 둘째, 교사관계는 자기주도학습에 정적인 영향을 주었고, 친구관계는 자아존중감에 정적 영향을 나타내었다. 셋째, 자아존중감은 청소년의 자기주도학습에 정적 영향을 주는 것으로 드러났 다. 넷째, 부모자녀관계는 자아존중감을 부분매개로 자기주도학습에 정적 영향을 주었고, 친구관계는 자아존중감을 완전매개로 자기주도학습에 정 적 영향을 미쳤다. 본 연구결과는 청소년의 자기주도학습 수준을 높이기 위한 사회적 지지 개선방안 모색, 교육정책 및 프로그램 수립의 근거 연 구로 활용될 수 있다.

In this study, the SBC system, a new mechanical joint method, was developed to improve the constructability of precast concrete (PC) beam-column connections. The reliability of the finite element analysis model was verified through the comparison of experimental results and FEM analysis results. Recently, the intermediate moment frame, a seismic force resistance system, has served as a ramen structure that resists seismic force through beams and columns and has few load-bearing walls, so it is increasingly being applied to PC warehouses and PC factories with high loads and long spans. However, looking at the existing PC beam-column anchorage details, the wire, strand, and lower main bar are overlapped with the anchorage rebar at the end, so they do not satisfy the joint and anchorage requirements for reinforcing bars (KDS 41 17 00 9.3). Therefore, a mechanical joint method (SBC) was developed to meet the relevant standards and improve constructability. Tensile and bending experiments were conducted to examine structural performance, and a finite element analysis model was created. The load-displacement curve and failure pattern confirmed that both the experimental and analysis results were similar, and it was verified that a reliable finite element analysis model was built. In addition, bending tests showed that the larger the thickness of the bolt joint surface of the SBC, the better its structural performance. It was also determined that the system could improve energy dissipation ability and ductility through buckling and yielding occurring in the SBC.

This study investigated the species composition and community structure of aquatic organisms captured using coastal beam trawling in Gomso Bay, Jeollabuk-do, from January to December 2022. Throughout the experimental period, a total of 20,246 individuals belonging to 94 marine species were captured, with a combined biomass of 602,828 g. Fish exhibited the highest abundance, comprising 56 species, followed by crustacea (21 species), bivalvia (8 species), cephalopoda (5 species), gastropoda (3 species), and holothuroidea (1 species). The dominant species was Leiognathus nuchalis, constituting 14.0% of the total individuals, followed by Portunus trituberculatus at 12.1%, Oratosquilla oratoria at 10.4%, Crangon hakodatei at 9.9%, and Metapenaeus joyneri at 7.9%. The diversity index ranged from 1.72 to 2.55, with the lowest diversity observed in March and the highest in July. Cluster analysis based on species composition of the 27 most common species showed that aquatic organisms were divided into three groups: spring and summer organisms (Group A) and summer organisms (Group B) and autumn and winter organisms (Group C).

본 연구는 한국수어 교육의 양적 확장이 이뤄졌음에도 농인들과의 의사소통이 가능한 청인들이 증가하지 않은 이유를 한국수어 교재의 문제점들에 주목하였다. 한국수어 교재들이 언어학적인 교육과정을 담아내야 한다는 전제하에 한국수어 교재들과 미국수어 교재들을 비교 분석하여 이를 토대로 한국수어 교재의 재구조 화 방안을 제시하는 데에 연구목적을 설정하였다. 분석 대상은 한국수어 교재 12권과 미국수어 교재 2권이었 다. 연구 결과, 외적 구성과 교재 내적인 차원에서의 전체 구성, 학습 내용에서의 주제와 어휘 및 회화 영역에서 한국과 미국 교재들 간의 뚜렷한 차이를 발견하였다. 이에 따른 몇 가지 논의사항은 첫째, 미국수어 교재의 외적 구성은 미국농인이 익숙하며 선호하는 시각적 정보화에 충실했다는 것이다. 둘째, 한국수어 교재들은 미국수어 교재들에 비해 내적 구성에서 ‘계속성’과 ‘계열성’이 미흡하였다. 셋째, 양질의 수어교재 들이 미국에서 개발될 수 있었던 계기들로는 수십 년에 걸친 기초연구들이 뒷받침되어 있었다. 넷째, 언어 교수·학습을 위한 교재가 학습자들에게 유용하도록 짜임새 있게 구성되기 위해서는 언어이론에 근거한 교재를 개발해야 한다. 본 연구의 제언으로는 첫째, 현재 진행 중인 국립국어원에서 발주하여 전문 연구진에 의해 연구되고 있는 한국수어능력 등급별 평가기준 마련, 한국수어교원 2급 교육과정 개선, 한국수어교원 1급 교육과정 개발 등이 최대한 빨리 이뤄져야 한다. 둘째, 미국수어 교재에서 적용하는 농인 친화적인 외적 구성 형태를 모범으로 삼아야 한다. 셋째, 학습 주제, 학습 어휘 및 회화 등 실제 학습 내용을 구성하게끔 하는 한국수어 교육과정의 이론과 방법이 모색되어야 한다. 넷째, 기존 교재들의 재구조화와 그에 따른 향후 신규 개발된 한국수어 교재들을 지속적으로 평가하는 지침과 기준이 마련되어야 한다.