• Title/Summary/Keyword: case histories

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Effect of new audio magnetolluric equipment for groundwater investigation in water barren area

  • Lunkai Yang;Hong Liu;Zhanxiang He
    • 한국지구물리탐사학회:학술대회논문집
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    • 2003.11a
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    • pp.398-401
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    • 2003
  • This paper deals with the recent achievements in AMT data acquisition and processing, which have improved the quality of the collected data,. Comparing AMT with VES, IP and logging data, it is concluded through some case histories that qualified results can be achieved in probing the karst water with AMT technique.

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A Review of the Last Century Construction Failures and the Observational Method in Geotechnical Engineering (지반과 관련된 지난 세기의 건설사고와 정보화 시공)

  • 김학문
    • Proceedings of the Korean Geotechical Society Conference
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    • 2000.03c
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    • pp.1-36
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    • 2000
  • Construction incidents, mechanisms and causes in Geotechnical Engineering have been closely reviewed for the safety assurance during design and construction stages. The safety assurance is clearly related to the observational method in which design is reviewed during construction and contingency actions are undertaken successfully to minimise any potential failures. The observational method has been extensively applied for the construction of subways underground structures, dams and many important Civil Engineering projects in the past 20 years. But the number of serious construction incidents are growing for the past several decades. Therefore present development of observational method and improvement techniques are introduced with some case histories.

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The Development and Application of KOESWall System (분리형 보강토 옹벽의 개발 및 적용사례)

  • 김영윤
    • Proceedings of the Korean Geotechical Society Conference
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    • 2001.10a
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    • pp.323-328
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    • 2001
  • In the ordinary reinforced earth wall, which was constructed by incremental construction method, the horizontal deformation of the facing due to the compaction induced horizontal earth pressure was unavoidable. Thus the KOESWall system which are adopted the isolated construction method was developed by I&S Eng. Co., Ltd. in 1999. Due to its systematical feature, KOESWall system is able to minimizes the horizontal deformation of reinforced wall effectively and it can be used as temporary structures more economically without the lacing block. In this report, it is shown that the concept and case histories of KOESWall system as a retaining structures.

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A Study on the Reinforced Characteristic of Geogrids in Multi-Layered System (다층 시스템에서 지오그리드의 보강특성에 관한 연구)

  • 심재범;신은철;신민호;채영수
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.03a
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    • pp.533-540
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    • 2002
  • Recently, geogrid reinforcement has been applied tn the subgrade of the roadway and the railway on the compressible layered soil, and the relevant reserch on the reinforcing mechanism has been performed. In this study, mechanics of geogrid reinforcement and the parameters for the improvement of bearing capacity are evaluated and presented based on the case histories of the field load test on the geogrid-reinforced layered subgrade

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Investigation of Tieback wall Behavior based on Generated Mass Movement (Mass Movement가 타이백 앵커 벽체의 거동에 미치는 영향평가)

  • 임유진
    • Journal of the Korean Geotechnical Society
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    • v.16 no.5
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    • pp.83-92
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    • 2000
  • 벽체의 수평변위 중 토체의 침하 및 앵커체 자체의 움직임 등으로 인해 발생하는 mass movement가 타이백 앵커토류벽의 거동에 미치는 영향을 조사하였다. 시공사례에 대한 유한요소 해석을 실시하여 벽체의 변위, 겉보기토압, mass movement 및 앵커 자유장 내에서의 하중 변화를 투적하였다. 유한요소해석법을 이용해 mass movement를 계산, 예측할 수 있었으며, 시공 순서에 따흔 앵커 자유장 내의 하중변화를 예측할수 있었다. 현장계측결과와 유한요소해석결과로부터 벽체변위, 겉보기토압 및 앵커의 하중 변화에 미치는 mass movement의 영향이 매우 큼을 확인 할 수 있었다.

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The effect of local topography on the seismic response of a coupled train-bridge system

  • Qiao, Hong;Du, Xianting;Xia, He;De Roeck, Guido;Lombaert, Geert;Long, Peiheng
    • Structural Engineering and Mechanics
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    • v.69 no.2
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    • pp.177-191
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    • 2019
  • The local topography has a significant effect on the characteristics of seismic ground motion. This paper investigates the influence of topographic effects on the seismic response of a train-bridge system. A 3-D finite element model with local absorbing boundary conditions is established for the local site. The time histories of seismic ground motion are converted into equivalent loads on the artificial boundary, to obtain the seismic input at the bridge supports. The analysis of the train-bridge system subjected to multi-support seismic excitations is performed, by applying the displacement time histories of the seismic ground motion to the bridge supports. In a case study considering a bridge with a span of 466 m crossing a valley, the seismic response of the train-bridge system is analyzed. The results show that the local topography and the incident angle of seismic waves have a significant effect on the seismic response of the train-bridge system. Leaving these effects out of consideration may lead to unsafe analysis results.

Allergic reactions to local anesthetic mepivacaine in dental procedures: a case report

  • Yoonhyoung Nam;Seyeon Min;Wonse Park;Kee-Deog Kim
    • Journal of Dental Anesthesia and Pain Medicine
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    • v.23 no.3
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    • pp.173-177
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    • 2023
  • Local anesthetics are an essential part of pain control during dental treatment. Despite its effectiveness and safety, patients should constantly be aware of potential adverse effects, including allergic reactions. Allergic reactions to amide-type local anesthetics (LAs), such as lidocaine and mepivacaine, are rare compared to those to ester-type LAs. Herein, we report the case of a patient with a history of allergy to lidocaine and mepivacaine, with symptoms of itching, diffuse erythema of the wrists and hands, dizziness, and pectoralgia. This case report emphasizes the importance of collecting medical and dental histories of patients is necessary, and how an allergy test in the allergy and clinical immunology department helps select safe LAs for patients.

A Case Study on Application of O-cell Test in Oversea (양방향재하시험의 국외 적용 사례)

  • Lee, Won-Je;Molnit, Thomas
    • Proceedings of the Korean Geotechical Society Conference
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    • 2006.10a
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    • pp.593-602
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    • 2006
  • 대구경 현장타설말뚝에 대한 시험하중의 증가와 함께 적용이 활성화되고 있는 오스터버그 셀(Osterberg cell)방식이 적용된 국외의 4 개소 시험결과에 대하여 소개하였다. 사례연구의 대상이 된 4 개소 시험말뚝은 일반적인 시험보다는 결과상의 특징이 있어 현재 및 향후 동일한 시험방법이 적용될 경우 고려될 수 있는 내용을 중심으로 기술하였다. 이들 말뚝시험에서는 가장 전형적으로 지지력의 균형이 이루어져 말뚝의 극한현상이 발생되지 않아 설계하중을 충분히 확인한 경우뿐 아니라 선단지지력이 부족하여 선단 그라우팅 후 재시험을 한 경우, O-cell을 말뚝의 선단에 가장 근접하여 설치 한 후 시험한 경우, 그리고 다단면(multi-level test)시험이 수행되었던 예 등을 살펴보았다.

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A Study on Machine Fault Diagnosis using Decision Tree

  • Nguyen, Ngoc-Tu;Kwon, Jeong-Min;Lee, Hong-Hee
    • Journal of Electrical Engineering and Technology
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    • v.2 no.4
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    • pp.461-467
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    • 2007
  • The paper describes a way to diagnose machine condition based on the expert system. In this paper, an expert system-decision tree is built and experimented to diagnose and to detect machine defects. The main objective of this study is to provide a simple way to monitor machine status by synthesizing the knowledge and experiences on the diagnostic case histories of the rotating machinery. A traditional decision tree has been constructed using vibration-based inputs. Some case studies are provided to illustrate the application and advantages of the decision tree system for machine fault diagnosis.

Aerodynamic Load Analysis for 1MW HAWT Blade According to IEC61400-1 (바람조건에 따른 1MW급 수평축 풍력터빈 브레이드의 하중 해석)

  • Kim, Jin;Ryu, Ki-Wahn;Lee, Chang-Su
    • 한국신재생에너지학회:학술대회논문집
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    • 2007.06a
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    • pp.409-413
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    • 2007
  • To assure the structural integrity for the hub and low speed shaft (LSS) of the drive train, it is necessary to obtain the ultimate aerodynamic loads acting on the wind turbine blade. The aim of this study is to predict the time histories of 3 forces and 3 moments at the hub and the LSS based on the design load case of the IEC 61400-1. From the calculated results most of the load components have rotor revolution frequency whereas thrust and torque of the LSS show blade passage frequency. It turns out that the EWM wind condition involves the maximum ultimate loads at both hub and LSS of the horizontal axis wind turbine.

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