• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.5 s.39
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• pp.25-33
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• 2004

To evaluate the seismic capacity of a multistorey building structures in performance based seismic design, it is needed to convert MDOF model into equivalent SDOF model. This paper presents predictions for interstory drift of multistorey structures using method of converting a MDOF system into an equivalent SDOF model. The principal objective of this investigation is to evaluate appropriateness of converting method through performing nonlinear time history analysis of a multistory building structures and an equivalent SDOF model. Comparing the interstory drift of multistorey structures calculated by time history analysis and those evaluated by an equivalent SDOF model, the adequacy and the validity of converting method is verified. The conclusion of this study is following; A method of converting a MDOF system into an equivalent SDOF model through the nonlinear time history response analysis is valid. Inelastic first mode shapes are expected to be more accurate than elastic first mode shapes in obtaining interstory drift of multistorey structures from equivalent SDOF model.

• Journal of Oral Medicine and Pain
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• v.23 no.1
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• pp.37-44
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• 1998

본연구는 서울대학교 치과병원 구강진단과 악안면 동통진료실에 내원한 환자 중 임상적 검사에 의해 악관절 내장증으로 진단된 총 32명 53개의 측두하악 관절을 대상으로 악관절 조영술이나 자기공명영상을 실시하여 임상적 진단의 정확도를 알아보고 향후 이 결과를 적절히 활용하여 정확한 적응증의 설정에 도움을 주고자 시행되었다. 각 악관절을 임상적 검사, 조영술 및 자기공명영상 검사를 기준으로 정상, 정복성 관절원판 변위, 비정복성 관절원판 변위, 퇴행성 관절 질환을 동반한 정복성 관절원판 변위, 퇴행성 관절 질환을 동반한 비정복성 관절원판 변위로 구분하였다. 이상의 연구를 통하여 다음과 같은 결론을 얻었다. 1. 악관절 내장증으로 내원한 환자 32명, 총 53개 관절중, 정상인 경우가 5예, 정복성 관절원판 변위인 경우가 33예, 비정복성 관절원판 변위인 경우가 14예, 퇴행성 관절 질환을 동반한 정복성 관절원판변위인 경우가 1예이었고, 퇴행성 관절 질환을 동반한 비정복성 관절원판 변위인 경우는 없었다. 2. 악관절 조영술 검사를 시행한 35개의 관절중 임상적 검사와 일치하는 경우는 32개로 그 일치율은 91.1%이었으며, 자기공명영상 검사를 시행한 28개의 관절중 임상적 검사와 일치하는 경우는 20개로 그 일치율은 71.4%이었다. 3. 악관절 조영술 및 자기공명영상 검사를 동시에 시행한 10개 관절중 악관절 조영술 및 자기공명영상검사가 일치하는 경우는 9개이었으며 이중 8개 결과는 임상적 진단과 일치되는 소견을 보였다. 임상적 검사는 악관절 내장증의 진단에 유용한 방법임이 확인되었다. 그러나 임상적으로는 정상으로 진단되었지만 주관적인 증상을 가진 환자에게는 자기공명영상 검사와 악관절조영술 검사 등의 영상진단술식이 필요할 것으로 사료된다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.9 no.3
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• pp.229-240
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• 2007

The 3D absolute displacement monitoring system has been developed to analyze the tunnel convergence measured under construction of underground structures and to manage effectively the measured data. The system is comprised of the total station, the anchor-typed target pin and the 3D absolute displacement measurement and management program. In this paper, the types and specifications of the 3D total station were presented. The anchor-typed target pin, an improved model of traditional one, was developed and its sightable distance and measurement accuracy were checked by field tests. Also a 3D absolute displacement measurement and management program, TEMS 3D, was developed to provide some analysis tools including the trend and influence lines. L/C ratio, S/C ratio and the like. The developed system was applied the construction stage of a railway tunnel for testing purpose. It is verified that the developed system is capable of predicting weak zones ahead of tunnel face by comparing with results of TSP (Tunnel Seismic Prediction) survey.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.5
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• pp.396-404
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• 2015

The UAV's wing has high aspect ratio that is suitable for the high altitude and long endurance. Knowing the real-time deformation of wing structure in flight, it can be utilized in structural health and loading status monitoring, improvement of control effectiveness and extraordinary vibration phenomena using displacement-strain relationship. In this paper, nonlinear displacement prediction algorithm was developed for prediction of large structural deflection in flight. The algorithm was validated through the comparison with finite element analysis results and also experimental results for several large tip displacements of cantilever beam. The predicted displacements using strains are agreed well with the measured values from laser displacement sensor.

• Journal of Korean Tunnelling and Underground Space Association
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• v.8 no.2
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• pp.101-113
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• 2006

Arching effect occurs around the unsupported excavation surface near to tunnel face when a tunnel is excavated in a stable rock mass. If a weak fracture zone exists in front of tunnel face, a displacement occurs between tunnel face and weak fracture zone due to stress concentration. If three-dimensional absolute coordinates (longitudinal, transverse, vertical direction) is measured at tunnel face by geodetic method, the ground change in front of the tunnel face can be predicted by analysing three-dimensional absolute displacement. The purpose of this study is to verify the analysis method of three-dimensional absolute displacement by comparing the trend of displacement ratio at crown and sidewall of tunnel and the influence line/trend line of crown settlement compared with TSP results in the same section.

• Tunnel and Underground Space
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• v.13 no.6
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• pp.476-485
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• 2003

The purpose of this study is to present an analysis method for the prediction of the change of ground conditions. To this end, three-dimensional convergence displacements is analyzed in several ways to estimate the trend of displacement change. Three-dimensional arching effect is occurred around the unsupported excavation surface including tunnel face when a tunnel is excavated in a stable rock mass. If the ground condition ahead of tunnel face changes or a weak fracture zone exists a specific trend of displacement change is known to be occurred from the results of the existing researches. The existence of a discontinuity, whose change in front of the tunnel face, can be predicted from the ratio of L/C (longitudinal displacement at crown divided by settlement at crown) etc. Therefore, the change of ground condition and the existence of a fracture zone ahead of tunnel face can be predicted by monitoring three-dimensional absolute displacements during excavation, and applying the methodology presented in this study.

• Korean Journal of Remote Sensing
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• v.27 no.5
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• pp.535-542
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• 2011

We extracted a surface displacement map of Canisteo Peninsula and the surrounding area in West Antarctica by applying 4-pass DInSAR technique to two ERS-1/2 tandem pairs and analyzed the surface displacement of glaciers and sea ice. In the displacement map, glaciers showed fast motion pushing the adjoining land-fast sea ice which has the displacement in the same direction as the glacier. Cosgrove ice shelf showed large displacement pushing the adjoining land-fast sea ice as well. Some sea ice indicated the displacement that is opposite to the land-fast sea ice. This was because the type of the sea ice is drift ice that is affected by ocean current. Therefore, we could confirmed the boundary between land-fast sea ice and drift ice. It was difficult to distinguish ice shelf from ice sheet because they showed similarities both in brightness of the SAR images and in fringe rates of the interferograms. However, a boundary between fast-moving ice shelf and stable ice sheet was easily confirmed in the displacement map after the phase unwrapping process.

• Geotechnical Engineering
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• v.14 no.6
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• pp.81-92
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• 1998

A beam on elasto-plastic foundation modeling of soldier pile and woodlagging tieback walls or anchored walls was developed and tested. An instrumented full scale tieback wall in sand was constructed at the National Geotechnical Experimentation Bite located on Texas A&M University. The experimental earth pressure deflection relationship (p-y curves) was developed from the measurements. The construction sequence was simulated in the proposed method. The conceptual methodology of an anchored wall design was introduced by using the proposed method. The proposed method was evaluated with the measurements of case histories in sand and clay. A parametric research was performed to study the most influencing factors for the proposed method. It is concluded that the proposed method represents a significant improvement on the prediction of bending moments and deflections of the properly designed walls.

• Journal of the Korean GEO-environmental Society
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• v.9 no.7
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• pp.13-23
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• 2008

In this study, the centrifuge tests and numerical analyses were performed to investigate the lateral flow behavior and stability of abutment when high filling was applied on the soft ground improved by SCP. The centrifuge model tests and numerical analyses were fulfilled in the case of the back of abutment filled by EPS (case 1) and soil (case 2), and the potentiometer was installed on the abutment and fill to measure the vertical and horizontal displacement at the top of abutment. As a result of the centrifugal tests, the horizontal displacement of abutment in the case 1 was 1.4cm that is almost coincide with the results of numerical and satisfy the allowable standard. On the other hand, the horizontal displacement of abutment in the case 2 was 12 cm that is 18% greater than that of numerical analysis and exceed the allowable standard. As a result of analysis, the maximum horizontal displacement of pile was 1.26 cm in case 1 that satisfies the criterion of allowable horizontal displacement (1.5 cm). In contrast, the maximum horizontal displacement of pile was 1.005 m in case 2 that greatly exceeds the allowable horizontal displacement.

• Journal of the Korean Geotechnical Society
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• v.15 no.5
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• pp.259-279
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• 1999

Model tests on propped retaining walls were performed for the investigation of wall displacement, distribution of earth pressure, surface settlement and underground movement at various excavation stage in sand. The result of model tests on the trough of surface settlement showed considerable difference depending on the characteristic of wall stiffness, wall friction and soil condition. The location of maximum underground movement were found to be at range of 0.15H to 0. 1H(H: Final excavation depth). Effect of arching by the redistribution of earth pressure were closely related to the stiffness of wall as well as the soil condition. The wall displacement and earth pressure distribution were simulated by elasto - plastic beam analysis program and finite element method with GDHM model respectively. The result of elasto-plastic analysis showed some discrepancy on the wall displacement and earth pressure, but result of underground movement by FEM with various wall stiffness were in good agreement with the model tests.