• Journal of the Korean Geotechnical Society
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• v.22 no.12
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• pp.33-43
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• 2006

Driving tests using model plastic piles with different hammer cushion materials were performed in order to evaluate the efficiency of energy transfer ratio from the hammer, degree of vibration of the surrounding ground and noise due to impacting. A small pile driving analyzer (PDA) was composed using straingages and Hopkinson bar which is measuring force signal and pile-head velocity. The hammer cushion (cap block) materials used for the model driving tests were commercial Micarta, plywood, polyurethane, rubber (SBR) and silicone rubber. The highest energy transfer ratio was obtained from Micarta in the same soil and driving conditions. Micarta was followed by polyurethane, plywood, rubber and silicone in descending order. The more efficient energy transfdr ratio of the hammer cushion materials became, the bigger average noisy (sound) level was found. In addition, Micarta and polyurethane provided bigger bearing capacities than other materials compared in the same soil and driving conditions in which the static loading tests were performed at the end of driving.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.4A
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• pp.457-463
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• 2008

The longitudinal stiffener performs its role to increase the local buckling strength by making simple support upon compression flange. In the recent researches, it is investigated that compression flange with point supports on certain arrangement reveals the same strength with longitudinal stiffeners. From this results, it is predictable that shear stud could perform the role of longitudinal stiffener if shear stud embedded in concrete satisfies the requirement to point-support under yield stress of the compression flange. In this study, the researches were performed to investigate the optimally required arrangement space of longitudinal point-support for which the shear stud replacing the longitudinal stiffeners and simultaneously determine the required numbers and space of shear stud for completely composite behavior between compression bottom flange and bottom concrete on the double composite girder system.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3A
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• pp.367-373
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• 2008

In the design of horizontally curved plate girder web panels, it is required to evaluate accurately the elastic buckling strength under pure shear. Currently, elastic shear buckling coefficients of curved web panels stiffened by transverse intermediate stiffeners are determined by assuming conservatively that straight web panels without curvature are simply supported at the juncture between the flange and web. However, depending upon the geometry and the properties of the curved plate girder, the elastically restrained support may behave rather closer to a fixed support. The buckling strength of curved girder web is much greater (maximum 38%) than that of a straight girder calculated under the assumption that all four edges are simply supported in Lee and Yoo (1999). In the present study, a series of numerical analyses based on a 3D finite element modeling is carried out to investigate the effects of geometric parameters on both the boundary condition at the juncture and the horizontal curvature of web panel, and the resulting data are quantified in a simple design equation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.2
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• pp.17-26
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• 2024

In recent times, accidents involving structural elements, formwork, and shore have been persistently occurring during concrete pouring, especially in multi-story reinforced concrete (RC) structures. In previous studies, research on construction load analysis was mainly conducted for cases where the thickness of all slabs is constant. However, when the thickness of some slabs is different, the variation in the stiffness of slab cross-sections can lead to different distributions of construction loads, necessitating further investigation. In this study, the slab thickness was set as a variable, and the analysis of the distribution of construction loads was conducted, taking into account the influence of changes in slab thickness on the concrete stiffness and structure. It was confirmed that not only the concrete material stiffness but also the slab cross-section stiffness should be considered in the estimation of construction loads when the slab thickness changes. As the slab thickness increases, the maximum construction load and maximum damage parameter on the layer with increased thickness significantly increase, and it was observed that a thicker slab results in a higher proportion of construction load.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.461-462
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• 2008

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.161-168
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• 2003

평판재하시험은 재하시험시 표층의 매우 잘 다져진 곳에 대한 지지력 계수를 획득하여 실다짐도를 과대 평가하는 결과를 초래할 수 있다. 이에 착안하여 응력도달 범위가 작은 평판재하시험을 지양하고 콘관입시험으로부터 획득되는 노상의 관입지수로부터 지반의 다짐도를 추정할 수 있는 콘관입시험기와 구동시스템 및 해석 프로그램을 개발하였다.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1995.06b
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• pp.14-20
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• 1995

본 연구에서는 압축기내의 이상류, 즉 냉매와 오일의 혼합상태라 하는 특수한 환경에서 하중을 지지하고 있는 상하부 베어링에서의 윤활특성파악을 위하여, 압축기의 동역학해석 및 레이놀즈방정식을 이용, 베어링의 축심궤적을 수치해석에 의해 결정하고, 여러 운전조건에서 축심궤적의 변화를 살펴 보았다. 또한, 실험에서는 실제의 냉방시스템에 사용되고 있는 로터리 압축기의 축심궤적을 갭-센서를 이용하여 파악, 그 결과를 나타냈다.

• Electronics and Telecommunications Trends
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• v.12 no.2 s.44
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• pp.32-51
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• 1997

누구나 한번쯤은 CORBA, OLE, COM/DCOM, SOM, DCE와 같은 분산 객체 기술의 핵심이 되는 용어들을 들어 봤을 것이다. 이러한 분산 객체 기술은 현재 우리가 접하고 있는 컴퓨팅 세계에서 가장 중요한 핵심 기술이라 해도 과언이 아니다. 본 고에서는 이들 중에 가장 대중의 관심과 지지를 받고 있는 CORBA의 객체 지향 기술을 살펴보고, 그를 구현한 상용 제품들의 기능을 비교해 봄으로써, 향후 분산 개발 환경을 이용한 시스템 개발에 필요한 사항을 알아보고자 한다.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2005.05a
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• pp.218-222
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• 2005

• Proceedings of the Korea Society for Industrial Systems Conference
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• 1998.10a
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• pp.489-508
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• 1998

서비스 기업들은 경쟁우위를 달성하기위해 서비스 인카운터를 제고하는 것이 바람직하다. 서비스인카운터는 서비스파업, 서비스생산시스템, 서비스표준으로 구성되므로 이들간의 전략적 일관성에 노력을 기울여야 한다. 본 연구에서는 서비스 인카운터를 제고하기 위한 방안으로 서비스 기업의 경쟁전략과 하위전략인 MIS전략의 적합성을 경쟁전략, 서비스 생산구조, MIS과업, MIS전략구조로 파악하여 금융산업과 유통산업을 대상으로 실증분석을 수행했다. 실증분석결과 특히 경쟁전략과 MIS 과업, 그리고 경쟁전략과 서비스 생산구조간의 전략적 적합성이 가설을 높게 지지하는 것으로 나타났다.