• Proceedings of the Korean Information Science Society Conference
• /
• 2004.04b
• /
• pp.841-843
• /
• 2004

응용프로그램 로더와 동적 링커는 응용프로그램이 실제로 실험되기까지의 준비 과정을 담당하는 프로그램들이다. 최근의 WIPI 표준은 휴대폰에 새로운 응용프로그램을 전송 받아 수행할 수 있는 환경을 제안하고 있지만, 휴대폰과 같은 제한된 이동단말기에서 사용할 안한 로더와 동적 링커는 공개되어 있지 않다. 본 논문에서는 이동단말기 환경에서 응용프로그램 로더와 동적 링커를 개발하는 과정을 설명한다. 개발에 참가한 연구진의 경험을 소개함으로써 이후의 비슷한 환경에서 로더와 링커를 개발하려는 연구자들에게 중요한 참고자료로 활용될 수 있을 것이다.

• Journal of the Society of Disaster Information
• /
• v.20 no.2
• /
• pp.369-378
• /
• 2024

Purpose: This study aims to verify structural stability by manufacturing a 40m full-scale specimen composed of a segmental U-shaped PSC girder with integrated tensioning systems and a concrete slab, proceeding dynamic behavior tests, and compare the results of the tests with the results of numerical analysis. Method: Dynamic behavior tests were conducted on a full-scale, undamaged specimen using an impact hammer, and the natural frequency and damping ratio were measured and compared with numerical analysis techniques and the general damping ratio of the facilities. Result: The natural frequency of the numerical analysis model consisting of a girder and slab composite section was calculated to be 2.561Hz, the natural frequency of the full-scale specimen was measured to be 2.670Hz, and the damping ratio was calculated to be 0.42~0.68%. Conclusion: The natural frequency of the full-scale specimen was found to be 4.3% larger than that of the numerical analysis model. Since the masses of the full-scale specimen and the numerical analysis model are the same as 99.97%, it can be derived that the stiffness of the full-scale specimen has secured structural safety and stability. As a result, the dynamic behavior stability of the specimen was verified. The measured damping ratio of 0.42~0.68% was found to be a stable dynamic behavior compared to the PSC structures damping ratio of 0.5~1.0% in the elastic region.

• Journal of Korean Society of Steel Construction
• /
• v.30 no.2
• /
• pp.67-76
• /
• 2018

An experimental study was conducted to evaluate the breakout strength of stirrup-reinforced cast-in anchors under dynamic shear loadings. The shear loadings were applied in the manner specified in the ACI 355.2 and ETAG 001 for the seismic qualification tests. Test specimens were fabricated with M36 anchor (edge distance, 180mm) reinforced with D10 stirrups (spacing, 100mm). The specimens reached almost the breakout strength and thereafter fracture of anchor occurred. Additional tests with M42 anchor (edge distance, 160mm) reinforced with D6 bars (spacing, 100mm) were also conducted. The experimental results showed that the dynamic shear strength was not less than the static resistance. Based on the test results, it was shown that ACI 318 and ETAG 001 specifications estimate the breakout strength of stirrup-reinforced anchors conservatively as more reinforcement is provided.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.26 no.1
• /
• pp.19-28
• /
• 2022

In this study, three types of combined isolator consisting of High Damping Rubber Bearing (HDRB) and wire isolator were developed for Uninterruptible Power Supply system (UPS). The dynamic characteristics of the combined isolator were investigated through one-axis shaking table test. The input acceleration were generated in accordance with ICC-ES AC156 code. Scale factors of the input acceleration were designed to be 0.5-2 times the required response spectrum defined in ICC-ES AC156. Based on the test results, damage and dynamic characteristics of the UPS were investigated: including natural frequency, damping ratio, acceleration time history response, dynamic amplification factor and relative displacement. Based on that, it was found that the combined isolator developed in this study could improve the seismic behavior of the UPS, in particular, the response acceleration.

• Tunnel and Underground Space
• /
• v.21 no.2
• /
• pp.109-116
• /
• 2011

In this study, we estimated the dynamic tensile strength and strain rate from Brazilian tensile test using Split Hopkinson Pressure Bar (SHPB) system. A pulse shaping technique, which controls the shape of the impactinduce incident waves, was used for achieving the dynamic stress equilibrium and constant strain rate before fracture of rock samples. Three kinds of rock type, Inada granite, Kimachi sandstone and Tage tuff were prepared as 50mm in diameter and 26 mm in thickness. The high-speed videography system was used to observe the fracture processes of the rock samples. As the results of the tests, the ratio of dynamic tensile strength and static tensile strength was 11.9 for Inada granite, 8.5 for Kimachi sandstone and 9.2 for Tage tuff.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.20 no.4
• /
• pp.463-468
• /
• 2007

Some network equipments made in Korea were exposed to severe earthquake in Japan several years ago. More than a hundred slim base transfer network stations had been seized with the severe earthquake at Nigata and it was reported that less than fifteen sets showed blackout by interruption of electricity, not by the structural failure. The purpose of this paper is to check the structural safety of the network equipments by performing table test, and the static and dynamic finite element analysis. For the dynamic test, the station weighing 200 kg was subjected to the Zone 3 earthquake loading of GR-63-CORE on the shaking table to obtain the dynamic responses to compare with the analysis results. It is shown that the FE analysis results are a little bit larger than that of the experimental values. And the sensitivity analysis and optimization for the natural frequency is performed and it is found that the first natural frequency is sensitive to small design change as shown in the results. And the dynamic response of optimized design is less than the original design.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.28 no.4
• /
• pp.202-211
• /
• 2016

This study aims to analyze seismic responses of suction foundations for offshore wind turbine. For this purpose, dynamic centrifuge model tests were carried out. The skirt length of the suction foundation is a critical element for bearing mechanism against environmental loads. Thus, dynamic centrifuge model tests were performed and analyzed for three suction foundation models with the ratios of skirt length to suction foundation diameter of 0.5, 0.75, and 1 installed in dense sand. As results, the acceleration amplification at the suction foundation, residual settlement, and residual tilting angle were compared.

• Tunnel and Underground Space
• /
• v.19 no.6
• /
• pp.545-557
• /
• 2009

In order to investigate dynamic damage mechanism of brittle materials, Split Hopkinson Pressure Bar (SHPB) have been adapted to apply different impact levels to rocks in South Korea. High resolution X-ray Computed Tomography (CT) was used to estimate the damage in tested rock samples nondestructively. The cracks which are parallel to the loading axis are visible on the contact surface with the incident bar under lower level of impact. The surface cracks disappeared with increment of impact level due to confined effect between the incident bar and sample, while axial splitting are happened near the outer surface.

• Journal of the Korean Society for Precision Engineering
• /
• v.13 no.2
• /
• pp.110-122
• /
• 1996

본 논문에서는 전기유동유체(Electro-Rheological Fluid : ERF)를 함유하는 지능구조물의 동적 모델링 및 진동제어를 수행하였다. 먼저 실리콘 오일을 기본용매로 하여 조성된 ERF의 복소 전단모듈러스를 전장부하와 가진 주파수의 함수로 동적 회전모드 실험을 통하여 도출한 후, 이를 샌드위치 보 이론과 연계하여 동적 모델링을 실시하였다. 도출된 6차 편미분방정식 형태의 지배 방정식을 유한요소 모델로 이산화하여 전장부하에 따른 지능구조물의 동탄성 특성값인 감쇠 고유 주파수 및 모달 손실계수를 주파수 영역에서 얻었다. 그리고 ERF를 함유한 샌드위치 형태의 지능구조물을 제작한 후 실험적으로 얻은 동탄성 특성값과 모델에 의해 예측된 동탄성 특성값을 비교 고찰하여 제시된 동적 모델에 대한 타당성을 입증하였다. 또한 모델을 통해 전장부하 함수로 예측된 주파수 응답곡선 중에서 각 주파수 대역에 대해 최소 변위가 되는 응답곡선을 요구응답으로 설정한 후, 그에 해당하는 전장부하를 선정하는 논리적인 능동 진동제어 알고리즘을 제안하였다. 제어알고리즘의 유용성을 입증하기 위해 실험적으로 수행된 능동 진동제어 결과를 주파수영역과 시간영역에서 제시하였다.

• Korean Chemical Engineering Research
• /
• v.60 no.1
• /
• pp.145-150
• /
• 2022

Dynamic contact angles have investigated by numerous researchers for understanding interfacial behavior at moving contact lines However, due to limitation of visualization techniques, previous experiments for dynamic contact angles have conducted limitedly in hydrophilic capillary tubes based on visible ray. Recently, there is continuous need for research on dynamic contact angles in hydrophobic capillary tubes on various research and industrial fields. Therefore, in this study, we measure the dynamic contact angles of water-glycerol mixture slug in hydrophobic microtubes using synchrotron X-ray imaging. Based on the visualized data, we verified the previous experimental correlations for dynamic contact angles.