• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.1
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• pp.713-722
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• 2009

Gravity measurement can determine the earth gravitational field, also is the fundamental to the research of earth gravitational field, geodesy and geodynamic, vertical movement of the crust, geoid surface, sea level and climate etc. Recently, National Geographic Information Institute (NGII) introduced FG-5 absolute gravity meter in order to lay a foundation for establishment of Absolute Gravity Network, and furthermore NGII plan to construct about 1,200 multi dimensional and function Unified Control Points(UCP) in nationwide. It will play an important role in development of high accuracy geoid model in South Korea. This paper explains the fundamental theory and method of relative gravity measurement, surveys the relative gravity of 21 stations using latest Scintrex CG-5 relative gravimeter. In addition, it calculates gravity values, compare and analysis gravity survey results using datum-free adjustment and weighted constraint adjustment. The results indicate show that datum-free and weighted constraint adjustment methods are available to determine high accuracy gravity achievement, datum-free method is more advantage than weighted constraint adjustment.

• Journal of the Korea Concrete Institute
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• v.13 no.3
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• pp.244-250
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• 2001

One of the reasons for brittle failure in reinforced concrete structures subjected to severe earthquake is due to large slip between reinforcing steel and concrete. This study aims to evaluate effects of deformation patterns of ribbed reinforcing bars on bond under cyclic loading. Bond test specimens were constructed with machined bars to test the newly developed reinforcing bars with high relative rib areas. The degree of confinement is also another key parameter in this bond test. From the test results under monotonic and cyclic loading, bond strength and stiffness were evaluated. Bond strength and bond stiffness increase as relative rib areas under cyclic loading for specimens highly confined by transverse reinforcement. The increase rates of the bond performance under cyclic loading are larger than those of specimens under monotonic loading. The developed bars with high relative rib areas will contribute for better bond performance for reinforced concrete structures subjected to severe seismic loadings.

• Korean Journal of Social Welfare
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• v.26
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• pp.135-164
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• 1995

자료분석 결과 발견된 사실들을 정리해 보면 다음과 같다. 첫째, 직장에서 발생하는 성적 성가심에 대해 상대적으로 적극적으로 대응하는 여성들은 약 50.6%정도로 나타났다. 이 중에서도 성적 성가심에 대해서 불쾌하게 인식하는 정도도 상대적으로 높고, 불쾌감을 상대에게 표현하며 대응하는 정도도 상대적으로 높은 여성들은 전체 응답자(736명)중에서 약 40%(294명)정도 였다. 성적 성가심에 대하여 불쾌함을 인식하는 정도는 상대적으로 낮으나 상대에게 불쾌함을 표현하며 대응하는 수준은 상대적으로 높은 여성들이 약 10.7%(79명)로 나타났다. 반면에 성적 성가심에 대하여 불쾌하게 인식하는 정도도 상대적으로 낮고 불쾌함을 상대에게 표현하는 정도도 낮은 여성들이 약 32.8%(242명)나 되었다. 약 16.4%(121명)의 여성들은 성적 성가심 상황에서 불쾌하게 인식하는 정도가 상대적으로 높으면서도 상대에게 불쾌감을 표현하며 대응하는 정도는 상대적으로 낮았다. <표 4> 둘째, 직장에서 발생하는 성적 성가심 상황에서 여성이 상대에게 성적 성가심에 대한 자신의 불쾌함을 표현하며 대응하는 능력은 여성의 심리적 특성인 대인의존성과 밀접한 관계가 있다는 사실을 명백하게 확인하였다. 성적 성가심 상황에서 성적 성가심에 대해 상대적으로 불쾌하다고 인식하는 정도가 높으면서 불쾌감을 표현하고 대응하는 수준은 상대적으로 낮은 여성들은 대인 의존도가 상대적으로 높았고, 반대로 성적성가심에 대해 상대적으로 불쾌하게 인식하는 정도가 상대적으로 낮으면서 불쾌감을 표현하며 대응하는 수준은 상대적으로 높은 여성들은 대인 의존도가 상대적으로 높게 나타났는데 이는 주목할만한 사실이다. 세째, 성장시 부모의 상호작용 유형이 성적 성가심과 같은 이성과의 상황에서의 여성들의 대응 반응과 밀접한 관련성이 있음을 발견하였다. 성장시 아버지가 지배적이고 어머니가 순종적인 특성이 뚜렷한 가정에서 성장한 여성들은 부모의 상호작용 유형이 동등한 가정 분위기에서 양육된 여성들에 비해 성적 성가심 상황에서 불쾌함을 표현하며 상대에게 대응하는 수준(강도)자체가 훨씬 낮았고, 성적 성가심에 대해 자신이 불쾌하게 생각하는 정도보다 상대적으로 훨씬 약한 소극적인 대응반응을 보이는 사실도 확인되었다. 성적 성가심 상황에서 상대 남성에 대한 여성들의 대응 반응은 성장시 남성인 아버지에 대한 여성인 어머니의 태도 및 행동의 재현(reenactment)현상으로 나타났다고 해석할 수 있다. 이러한 발견은 특히 동성인 부모가 성역활 사회화의 가장 강력한 모델이라는 학습 이론가들의 주장을 거듭 뒷받침하여 준다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.209-215
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• 2017

Ground Penetrating Radar (GPR) was applied to an evaluation of the concrete condition of bridge decks with asphalt concrete. Deterioration was considered to have occurred when the relative permittivity of a concrete-faced asphalt concrete overlay showed more than 12. The relative permittivity of concrete varied considerably with the levels of porosity and water. In this study, GPR tests were carried out to determine the influence of weather and concrete condition on the relative permittivity for the research subject of an overlaid concrete bridge deck in public service. According to the test results, if bridge decks are in good condition, the relative permittivity of the top concrete of a bridge deck exhibited a normal distribution. After the deck concrete deteriorated, the relative permittivity varied with the amount of penetrated water according to the weather condition and deteriorated status of deck concrete.

• Journal of the Korean Geotechnical Society
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• v.23 no.6
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• pp.67-76
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• 2007

Raining method has been widely used for preparing sand specimen because of its ability to reconstitute the homogeneous specimen with desired relative density and its reliability established by the numerous experiments on diverse influential factors. In conventional raining methods, adjustment of relative density is achieved by controlling the shutter porosity and the whole system is required to be re-adjusted to achieve the target relative density when the granular characteristics are changed. It is also observed from conventional methods that certain degrees of spatial variation in density exist and the limited range of relative density is reproduced. In this paper, raining system with porous plate is proposed. It is shown that the wide range of relative density can be achieved by controlling failing height only. This enhanced system is able to obviate the subtle control of shutter porosity and minimize the effect of falling distance, which in turn ensures the homogeneity of the specimen, especially for low relative density.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.2
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• pp.31-35
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• 2000

An nonlinear observer-based longitudinal control law for vehicles is presented in this paper. It is assumed that for vehicle i knows only the distance between vehicle i and the preceding vehicle, i-1. An nonlinear state observer for vehicle I is developed to estimate the velocity and acceleration of the preceding vehicle, i-1. The communication of the position, velocity, and acceleration information is not used in the proposed method. It will be shown by mathematical analysis that the longitudinal control of vehicle can be implemented without an communication of the informations. It will be proven that the observation errors of the nonlinear states converge to zero asymptotically. To show the effectiveness of the proposed method, the simulation results are presented for the longitudinal control of the vehicle.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.40 no.2
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• pp.19-25
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• 2003

For a class of multi-input multi-output nonlinear systems which perform a given task repetitively, an extended type of a direct leaning control (DLC) is proposed using the information on the (vector) relative degree of a multi-input multi-output system. Existing DLC methods are observed to be applied to a limited class of systems with the relative degree one and a new DLC law is suggested which can be applied to systems having higher relative degree. Using the proposed control law, the control input corresponding to the new desired output trajectory is synthesized directly based on the control inputs obtained from the learning process for other output trajectories. To show the validity and the performance of the proposed DLC, simulations are performed for trajectory tracking control of a two-axis SCARA robot.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.5
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• pp.19-29
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• 2006

In this study, numerical simulation of airframes separating from a missile system has been preformed. For the time-accurate trajectory simulation, six D.O.F equations of motion of multiply connected bodies were derived and these equations have been coupled with the unstructured overset mesh technique for the treatment of independent mesh blocks moving with each body component. Applications were made for the simulation of the airframe separation at missile angles of attack of 0 and 5 degrees. It was demonstrated that the present method is efficient and robust for the prediction of unsteady time-accurate flow fields involving multiple bodies in relative motion.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1999.10a
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• pp.119-120
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• 1999

응집은 입자들간의 상대운동에 의하여 두 입자가 충돌하여 하나의 입자가 되는 것을 말하는데, 상대 운동을 유발하는 원인에 따라 중력응집(gravitational coagulation)을 비롯하여 브라운응집(Brownian coagulation), 난류응집(turbulent coagulation)등으로 나뉜다. 브라운응집 및 난류응집에 비하여 상대적으로 중력응집은 해석적으로 풀기가 어렵고 실험에 대한 연구가 국내외는 물론 외국에서도 전무한 실정이다.(중략)

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.35-36
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• 2010

This research investigated the bond characteristic by lap splice experimental which has change relative area on rib variation of reinforcing bar. As a result has similar load-deflection curve with existing experiment, Maximum yield strength and displacement is increase.