• 디지털융복합연구
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• 제6권2호
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• pp.41-53
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• 2008

This research is to redefine the concept of Good School and to validate an effective Good Secondary School Scale in Kyung-gi Province and Seoul. As statistical methods, SPSS 13.0 and AMOS 5.0 were used. Item Analysis and Exploratory Factor Analysis(EFA) were conducted to test the reliability of items and the factor structure. And Confirmatory Factor Analysis(CFA) was conducted to test the validity and fitness of the Good School Scale. The outcomes are as follows: First, six factors(school environment, curriculum, teacher, school-based management system, director) will increase the good schooling effectiveness. Second, As a result of Confirmatory Factor Analysis(CFA), the goodness of fit indices(GFI AGFI, CFI, RMSEA) demonstrate statistically significance and fitness of the model. The final Good School Scale supports 6 Good School Factors obtained in main test. Therefore, we can say that this scale can be used as a valid instrument to measure a real Good Schooling Effectiveness at the secondary school situation in Korea.

• 한국항공우주학회지
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• 제45권2호
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• pp.99-105
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• 2017

공력탄성학적 현상들을 확인하는 방법 중 하나인 풍동실험은 축소 모델을 제작해야하기 때문에 복잡하고 비용이 많이 들며, 유동 속도의 제한이 있는 등의 단점이 있다. 이러한 단점을 보완하여 풍동실험을 대체할 수 있는 Dry Wind-Tunnel(DWT) 기법이 제안되었다. 이는 지상 진동 실험 장치와 공기력을 계산하는 소프트웨어로 구성되어 실시간으로 유체의 영향을 고려해준다. 본 연구에서는 DWT의 핵심적인 요소인 실시간 공기력 계산프로그램을 개발하고, 구조 모델을 소프트웨어로 표현하여 두 시스템을 실시간 연동해 플러터 해석을 수행하였다. Matlab Simulink와 dSPACE를 이용하여 실시간 플러터 해석을 수행하고 이를 상용프로그램인 ZAERO를 사용한 결과와 비교하여 검증하였다.

• 한국지진공학회논문집
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• 제9권1호통권41호
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• pp.43-50
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• 2005

도로교의 내진설계기준이 국내에 도입되어 적용된 것은 10여년에 불과하므로 아직 많은 교량에 내진성능 보강이 필요하다. 본 논문에서는 받침이 노후된 교량의 내진성능 보강방법으로서 적층고무받침으로 교체하는 방법의 타당성에 관하여 논하였다. 이를 위하여 내진상세가 없는 실물크기 RC교각 시험체를 제작하고 POT받침, 적층고무받침(RB), 납-적층고무받침(LRB)를 각각 설치하였다. 유사동적 실험을 통하여 이들 시험체의 지진시 거동을 모사하고 성능을 비교하였다. 실험결과로부터 제안된 내진보강기법의 타당성을 확인하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
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• pp.849-854
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• 2002

From the analysis results of some as-built drawings in national roadway bridges in Korea, many bridge piers are expected to show complex shear-flexural behaviour under earthquakes. But the previous research works about the seismic evaluation of bridges considered flexural behaviour RC piers only. In addition, the past bridge design specifications in Korea didn't include limitation on the amount of longitudinal lap splices in the plastic hinge zone of piers. Thus a large majority of non-seismically designed bridge piers in Korea may have lap splices in plastic hinge zone. In this study, prototype pier was selected among existent bridge piers whose failure mode is expected to be complex shear-flexural mode. And then, full scale and 1/2 reduced scale model RC piers with various longitudinal lap splice details were constructed. From the quasi static test results on these model RC piers, the effect of longitudinal lap splices on the seismic performance of bridges piers was analyzed. And the seismic capacity of the non-seismically designed shear-flexural RC piers was evaluated.

• 한국화재소방학회논문지
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• 제29권2호
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• pp.13-19
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• 2015

본 연구는 침윤소화약제의 소화성능평가를 위해 실규모 소화실험을 수행하였다. 실험은 '수동식소화기의 형식승인 및 검정기술기준'에 명시되어 있는 A급 소화실험 방법에 따라 진행하였으며, 목재 외에도 목분과 왕겨를 대상으로 실험을 진행하였다. 소화용수는 물과 국내에서 사용되고 있는 3종의 침윤소화약제를 사용하여 성능평가 실험을 진행함으로써 물과 침윤소화약제의 명확한 변별력을 확인하고자 하였다. 실험 결과 물의 경우에서 내부 온도의 유지시간이 길게 유지되고 침윤소화약제의 경우 빠른 온도 하강을 나타냄을 확인하였으며, 시간에 따른 온도분포를 통해 소화능력의 변별력을 확인하였다. 본 실험 결과를 바탕으로 추후 최적화 침윤소화약제 성능평가 방법을 제시하는데 기초자료로 활용할 수 있을 것으로 판단된다.

• Smart Structures and Systems
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• 제4권6호
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• pp.809-828
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• 2008

Real-time hybrid testing is an attractive method to evaluate the response of structures under earthquake loads. The method is a variation of the pseudodynamic testing technique in which the experiment is executed in real time, thus allowing investigation of structural systems with time-dependent components. Real-time hybrid testing is challenging because it requires performance of all calculations, application of displacements, and acquisition of measured forces, within a very small increment of time. Furthermore, unless appropriate compensation for time delays and actuator time lag is implemented, stability problems are likely to occur during the experiment. This paper presents an approach for real-time hybrid testing in which time delay/lag compensation is implemented using model-based response prediction. The efficacy of the proposed strategy is verified by conducting substructure real-time hybrid testing of a steel frame under earthquake loads. For the initial set of experiments, a specimen with linear-elastic behavior is used. Experimental results agree well with the analytical solution and show that the proposed approach and testing system are capable of achieving a time-scale expansion factor of one (i.e., real time). Additionally, the proposed method allows accurate testing of structures with larger frequencies than when using conventional time delay compensation methods, thus extending the capabilities of the real-time hybrid testing technique. The method is then used to test a structure with a rate-dependent energy dissipation device, a magnetorheological damper. Results show good agreement with the predicted responses, demonstrating the effectiveness of the method to test rate-dependent components.

• Smart Structures and Systems
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• 제31권6호
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• pp.601-619
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• 2023

In this study, the accuracy of a real-time hybrid test (RTHT) employed for a performance test of a tuned mass damper (TMD) on an offshore wind turbine (OWT) with a complicated jacket-type supporting structure is quantified and evaluated by comparing the RTHT results with the experimental data obtained from a shaking table test (STT), in which a 1/25-scale model for a typical 5-MW OWT controlled by a TMD was tested. In the RTHT, the jacket-type OWT structure was modelled using both multiple-DOF (MDOF) and single-DOF (SDOF) numerical models. When compared with the STT test data, the test results of the RTHT show that while the SDOF model, which requires less control computational time, is able to well predict the peak responses of the nacelle and TMD only, the MDOF model is able to effectively predict both the peak and over-all time-history responses at multiple critical locations of an OWT structure. This also indicates that, depending on the type of structural responses considered, an RTHT with either an SDOF or a MDOF model may be a promising alternative to the STT to assess the effectiveness of a TMD for seismic mitigation in an OWT context.

• 한국철도학회논문집
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• 제9권1호
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• pp.12-17
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• 2006

The bridge to be analyzed is a self-anchored suspension bridge which is constructed within the country. Forced vibration test was performed with oscillator for verification of safety, maintenance and management. In this study, the feasibility of deduction was verified with the modified analysis model by comparing natural frequency, natural mode and damping ratio of the real bridge, which are obtained from the vibration test of the whole bridge after construction of 3-dimensional self-anchored cable suspension bridge, with the eigenvalue of analytic computation model and evaluating them. As a result of study, the friction of bridge bearing must be considered to get the natural frequencies of flexural vibration, and evaluating the polar moment of inertia is critical factor in analysis modeling in case of torsional vibration. The logarithmic damping ratio of the test appeared to exceed the ordinary one assumed at the design phase.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.109-112
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• 2006

In this study, an approach that installs seismic isolation bearings was proposed for the seismic retrofit of the existing bridges. The method that replaces all existing bearings with seismic isolators was proposed already. However, in this study, we recommend to utilize the existing bearings for the benefit of safety and cost. According to our proposal, the seismic isolators do not support vertical loads but they just function as the period shifter and the horizontal damper. To verify this approach experimentally, the real scale bearings and isolators for the real highway bridges were designed and fabricated. And the responses of this isolated bridges to the assumed earthquakes were determined by the pseudo dynamic test scheme. The test results were also compared to the responses computed by the well known structural analysis software to check the reliability of the test. From the test results, we found that the retrofitted bridges using the proposed method showed stable performances under earthquakes.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.1553-1558
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• 2009

Give high priority to the technologies that can be directly applicable to the U-City development projects which are in progress by many central and local governments. Create a real world product at the end of R&D phase by testing prototypes in test-beds or test-labs. Recently, new construction technologies have been developed, but they are rarely being applied to the construction filed. In this paper, the basic design was examined so that various technologies can be selected through a test-bed, analyzed for the real situation, and applied to actual construction sites. Improve productivity of regional and urban construction exercises and improve competitiveness of related products and services using IT-based telemetering/GIS technology.