• 문화기술의 융합
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• 제7권4호
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• pp.291-297
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• 2021

현재의 공식적이고 암기식인 공예디자인 반복 훈련과 실습은 획일적인 평면적 디자인사고 표현에서 방황하고 있다. 이러한 평면적 현안 문제를 입체적 디자인 방식으로 변경하려면 통합된 융복합 교육목표 아래에서 학년별 방향을 설정하고 단계적으로 프로젝트를 수행하여 공예디자인에 대한 이해, 공간구성의 원리, 전통 디자인역사의 도입, 공예디자인의 총체적 접근 등 창작과 실무능력을 배양하여야 한다. 공예디자이너는 체계적인 교육과 훈련을 통해서만이 배출될 수 있다. 이는 다양한 시대변화의 요구에 대하여 스스로를 어떻게 적응해 나갈지에 대한 해결능력과 대처방안을 경험한 디자이너가 현장에 나와야 사회를 리드하고 성공할 수 있다. 교육 전문가들은 교육제도의 조직구조와 교과목의 혁신을 주장하며, 변화의 속도가 더욱 빠르게 진행될 21세기에 대응하는 교육의 중요성을 역설하였다. 본 연구는 이러한 문제에 대한 이해 및 분석을 통해 디자인과 인접학문이 연계된 융복합실습을 사회의 니즈를 반영한 프로젝트를 설정하여 과제를 구조적 접근에 의한 학문적 연구가 병행하는 교육체계를 제안하고자 한다.

• Structural Engineering and Mechanics
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• 제86권3호
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• pp.385-397
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• 2023

This study presents an experiment and analysis to compare the seismic behavior of full-scale reinforced concrete beam-column joint strengthened by prestressed steel strips, externally bonded steel plate, and CFRP sheets. For experimental investigation, five specimens, including one joint without any retrofitting, one joint retrofitted by externally bonded steel plate, one joint retrofitted by CFRP sheets, and two joints retrofitted by prestressed steel strips, were tested under cyclic-reserve loading. The failure mode, strain response, shear deformation, hysteresis behavior, energy dissipation capacity, stiffness degradation and damage indexes of all specimens were analyzed according to experimental study. It was found that prestressed steel strips, steel plate and CFRP sheets improved shear resistance, energy dissipation capacity, stiffness degradation behavior and reduced the shear deformation of the joint core area, as well as changed the failure pattern of the specimen, which led to the failure mode changed from the combination of flexural failure of beams and shear failure of joints core to the flexural failure of beams. In addition, the beam-column joint retrofitted by steel plate exhibited a high bearing capacity, energy consumption capacity and low damage index compared with the joint strengthened by prestressed steel strip, and the prestressed steel strips reinforced joint showed a high strength, energy dissipation capacity and low shear deformation, stirrups strains and damage index compared to the CFRP reinforced joint, which indicated that the frame joints strengthened with steel plate exhibited the most excellent seismic behavior, followed by the prestressed steel strips.

• 대한토목학회논문집
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• 제43권4호
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• pp.413-420
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• 2023

지진피해 감소를 위한 내진 구조 중에서 제진 구조는 댐퍼의 간단한 적용으로 효율적으로 내진 성능을 향상시키고 경제성을 확보할 수 있는 기술이다. 그러나 기존의 댐퍼는 요구 내진 성능과 재료 소성으로 인한 내구성에 대하여 한계를 나타낸다. 따라서 본 연구에서는 기본적으로 탄성 특성을 나타내는 폴리우레탄에 선행 압축을 가하고 초탄성 형상기억합금을 적용하여 복원 특성을 증진시킨 폴리우레탄 댐퍼를 제안하였다. 폴리우레탄 댐퍼의 특성을 검증하기 위하여 우선 개념을 정립하고 초탄성 형상기억합금과 강재 적용, 선행압축 크기를 설계 변수로 선정하여 설계 상세를 완성하였다. 또한, 구조 실험을 수행하여 응답 거동을 도출하여 하중 저항 성능, 잔류 변위, 회복률, 에너지 소산 능력을 분석하였다. 분석한 결과 폴리우레탄 댐퍼는 초탄성 형상기억합금 와이어를 적용하고 선행 압축이 증가하면 다양한 성능이 향상되는 결과를 나타냈다.

• Steel and Composite Structures
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• 제44권4호
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• pp.503-517
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• 2022

This paper presents the mechanical buckling of bi-directional functionally graded sandwich beams (BFGSW) with various boundary conditions employing a quasi-3D beam theory, including an integral term in the displacement field, which reduces the number of unknowns and governing equations. The beams are composed of three layers. The core is made from two constituents and varies across the thickness; however, the covering layers of the beams are made of bidirectional functionally graded material (BFGSW) and vary smoothly along the beam length and thickness directions. The power gradation model is considered to estimate the variation of material properties. The used formulation reflects the transverse shear effect and uses only three variables without including the correction factor used in the first shear deformation theory (FSDT) proposed by Timoshenko. The principle of virtual forces is used to obtain stability equations. Moreover, the impacts of the control of the power-law index, layer thickness ratio, length-to-depth ratio, and boundary conditions on buckling response are demonstrated. Our contribution in the present work is applying an analytical solution to investigate the stability behavior of bidirectional FG sandwich beams under various boundary conditions.

• 국제학술발표논문집
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• The 5th International Conference on Construction Engineering and Project Management
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• pp.640-647
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• 2013

Building Information Modelling (BIM) has become the new international benchmark for efficiency in design, construction and maintenance of buildings. It is the platform that brings about collaboration between project stakeholders and improvement of project outcomes. With all its potentials, not much of the impact of BIM technologies has been felt in the Nigerian construction industry. This research aimed at assessing the readiness of the Nigerian building design firms to adopt BIM technologies. The research was exploratory in nature. A field survey was conducted with the use of structured questionnaire, self administered to a sample of building design consultancy firms (architectural, structural, M&E, quantity surveying, and multi-disciplinary design firms) within Abuja and Kaduna. The questionnaire sought the perception of the responding firms on the factors affecting BIM adoption in the Nigerian construction industry, and their level of readiness to adopt BIM technologies in their practices based on the four categories of readiness-management, people, process and technology. 42.26% response rate was achieved and used for analysis. ANOVA and DUNCAN post-hoc tests were used to establish the differences between the responses of the groups of firms, while means and standard deviations were obtained to establish the important factors affecting BIM adoption in Nigeria. The survey revealed that all the groups of Nigerian design firms are appreciably ready for the adoption of BIM technologies in their practice, with slight variations in their respective levels of readiness. 'Lack of awareness of BIM technology among professionals' and clients and 'lack of knowledgeable and experienced partners' were identified as the most important barriers of BIM adoption in Nigeria; while the most significant drivers are 'availability of well trained professionals' and 'cooperation and commitment of professional bodies to the adoption'. Education and training of building design professionals and cooperation of all stakeholders in the design and construction supply chain were recommended as part of measures to ensure successful adoption of BIM in the Nigerian construction industry.

• Structural Engineering and Mechanics
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• 제90권1호
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• pp.27-40
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• 2024

The prediction of VIV amplitude is essential for the design and fatigue life estimation of steel tubes in tubular transmission towers. Limited to costly and time-consuming traditional experimental and computational fluid dynamics (CFD) methods, a machine learning (ML)-based method is proposed to efficiently predict the VIV amplitude of steel tubes in transmission towers. Firstly, by introducing the first-order mode shape to the two-dimensional CFD method, a simplified response analysis method (SRAM) is presented to calculate the VIV amplitude of steel tubes in transmission towers, which enables to build a dataset for training ML models. Then, by taking mass ratio M^*, damping ratio ξ, and reduced velocity U^* as the input variables, a Kriging-based prediction method (KPM) is further proposed to estimate the VIV amplitude of steel tubes in transmission towers by combining the SRAM with the Kriging-based ML model. Finally, the feasibility and effectiveness of the proposed methods are demonstrated by using three full-scale steel tubes with C-shaped, Cross-shaped, and Flange-plate joints, respectively. The results show that the SRAM can reasonably calculate the VIV amplitude, in which the relative errors of VIV maximum amplitude in three examples are less than 6%. Meanwhile, the KPM can well predict the VIV amplitude of steel tubes in transmission towers within the studied range of M^*, ξ and U^*. Particularly, the KPM presents an excellent capability in estimating the VIV maximum amplitude by using the reduced damping parameter S_G.

• IMMUNE NETWORK
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• 제20권4호
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• pp.33.1-33.19
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• 2020

We tested how adjuvants effect in a cancer vaccine model using an epitope derived from an autoactivation loop of membrane-type protease serine protease 14 (PRSS14; loop metavaccine) in mouse mammary tumor virus (MMTV)-polyoma middle tumor-antigen (PyMT) system and in 2 other orthotopic mouse systems. Earlier, we reported that loop metavaccine effectively prevented progression and metastasis regardless of adjuvant types and TH types of hosts in tail-vein injection systems. However, the loop metavaccine with Freund's complete adjuvant (CFA) reduced cancer progression and metastasis while that with alum, to our surprise, were adversely affected in 3 tumor bearing mouse models. The amounts of loop peptide specific antibodies inversely correlated with tumor burden and metastasis, meanwhile both T_H1 and T_H2 isotypes were present regardless of host type and adjuvant. Tumor infiltrating myeloid cells such as eosinophil, monocyte, and neutrophil were asymmetrically distributed among 2 adjuvant groups with loop metavaccine. Systemic expression profiling using the lymph nodes of the differentially immunized MMTV-PyMT mouse revealed that adjuvant types, as well as loop metavaccine can change the immune signatures. Specifically, loop metavaccine itself induces T_H2 and T_H17 responses but reduces T_H1 and T_reg responses regardless of adjuvant type, whereas CFA but not alum increased follicular T_H response. Among the myeloid signatures, eosinophil was most distinct between CFA and alum. Survival analysis of breast cancer patients showed that eosinophil chemokines can be useful prognostic factors in PRSS14 positive patients. Based on these observations, we concluded that multiple immune parameters are to be considered when applying a vaccine strategy to cancer patients.

• 한국구조물진단유지관리공학회 논문집
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• 제27권6호
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• pp.120-129
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• 2023

본 연구는 기존의 재하시험에 의한 계측 결과와 시험 열차 및 상시주행 열차 간의 결과 비교를 통해 주행 열차에 의한 재하시험을 검증하였다. 또한 계측된 자료로부터 정적,·동적 거동 특성을 추출하여 평가를 진행하여 재하시험의 신뢰성 검증을 위해 기존 계측자료와 열차속도, 노선 간 응답 비교, 경향분석, 충격계수 선정 및 고유진동수 분석을 통해 타당성을 입증하였다. 이를 위해 동호철교를 대상지로 적용하였으며 제안 방법의 적용성을 검증하였다. 상시 운행 열차 10대와 시험 열차를 이용하여 교량에 44개의 센서를 부착하고 재하시험 경간에 대한 변형률, 처짐 등을 계측하여 이론치와 비교분석 하였다. 분석 결과 하중의 대칭성 및 중첩성은 양호하며 정적 동적 재하시험 결과에 대한 비교 또한 양호한 것으로 나타났다. 충격계수 분석 결과 최대 실측 충격계수(0.092)가 이론충격계수(0.327)보다 작은 것으로 분석되어, 활하중에 의한 충격 영향은 양호한 것으로 판단된다. 실측 고유진동수는 최저 2.393Hz로 해석 값 2.415Hz와 비교 시 근사하게 평가되었다. 위 결과를 바탕으로 본 논문에서는 내하력 평가 시 열차의 통행 차단이 필요하지 않고, 기존의 처짐 및 응답 계측보다 계측이 용이하도록 트러스 교량구조의 응답 결과를 도출하였다. 주행 열차의 재하시험을 통해 트러스 철도 교량의 변형률 및 처짐을 측정하고 정적, 동적 거동 특성을 파악하여 응력보정을 위한 응답비 및 동적 강성을 평가할 수 있음을 보였다.

• 한국화재소방학회논문지
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• 제33권2호
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• pp.124-131
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• 2019

도로터널에서 화재가 발생하면 밀폐된 구조적 특성상 대형재난으로 발전할 가능성이 높기 때문에 각종 방재시설이 잘 설치되어 화재예방과 대응에 제 기능을 발휘해야 한다. 연속터널의 연장 및 방음터널을 고려하지 않아 필수 방재시설의 설치가 누락되어 법령의 개정이 필요한 것으로 판단된다. 이에 따라 본 논문에서 도로터널의 방재시설과 관련한 국내 법령들의 변천사항을 검토하고, 각 법령 간 비교분석을 통해 소방관계법령에서 개정이 필요한 부분을 연구한 결과는 다음과 같다. 첫째, 연속터널은 개별터널의 연장의 합을 고려하도록 하고 방음터널이 터널의 범주에 포함되도록 하여 필수 방재시설이 설치가 되지 않는 일이 없도록 해야 한다. 둘째, 터널 내 방재시설 설치의 법적 당위성 확보가 필요하므로 터널에 설치가 제외된 시설인 미분무소화설비, 비상방송설비, 유도등이 법령에 명시될 필요가 있다. 셋째, 현장대응의 입장에서 터널 내에 공기호흡기를 비치하도록 명시하여 소방대원들의 진압활동 및 인명구조에 크게 기여할 수 있도록 한다.

• Earthquakes and Structures
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• 제15권6호
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• pp.667-685
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• 2018

In eccentrically braced steel frames (EBFs), the links are fuse members which enter inelastic phase before other structure members and dissipate the seismic energy. Based on the force-based seismic design method, damages and plastic deformations are limited to the links, and the main structure members are required tremendous sizes to ensure elastic with limited or no damage. Force-based seismic design method is very common and is found in most design codes, it is unable to determine the inelastic response of the structure and the damages of the members. Nowadays, methods of seismic design are emphasizing more on performance-based seismic design concept to have a more realistic assessment of the inelastic response of the structure. Links use ordinary steel Q345 (the nominal yielding strength $f_y{\geq}345MPa$) while other members use high strength steel (Q460 $f_y{\geq}460MPa$ or Q690 $f_y{\geq}690MPa$) in eccentrically braced frames with high strength steel combination (HSS-EBFs). The application of high strength steels brings out many advantages, including higher safety ensured by higher strength in elastic state, better economy which results from the smaller member size and structural weight as well as the corresponding welding work, and most importantly, the application of high strength steel in seismic fortification zone, which is helpful to popularize the extensive use of high strength steel. In order to comparison seismic behavior between HSS-EBFs and ordinary EBFs, on the basis of experimental study, four structures with 5, 10, 15 and 20 stories were designed by PBSD method for HSS-EBFs and ordinary EBFs. Nonlinear static and dynamic analysis is applied to all designs. The loading capacity, lateral stiffness, ductility and story drifts and failure mode under rare earthquake of the designs are compared. Analyses results indicated that HSS-EBFs have similar loading capacity with ordinary EBFs while the lateral stiffness and ductility of HSS-EBFs is lower than that of EBFs. HSS-EBFs and ordinary EBFs designed by PBSD method have the similar failure mode and story drift distribution under rare earthquake, the steel weight of HSS-EBFs is 10%-15% lower than ordinary EBFs resulting in good economic efficiency.