• Journal of the Korean Geotechnical Society
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• v.19 no.4
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• pp.167-178
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• 2003

Damage and overbreak of the remaining rock induced by blasting can not be avoided during tunnel construction which may result in either short-term or long-term tunnel instability. Therefore, in this paper, a methodology to take into account the effect of blast-induced damage in tunnel stability assessment is proposed. Dynamic numerical analysis was executed to evaluate damage and overbreak of the remaining rock for the most common blasting pattern in road tunnel. Rock damage was quantified by utilizing the damage variable factor which is adopted proposed in continuum damage mechanics. The damaged rock stiffness and the damaged failure criteria are used to consider the effect of rock damage in tunnel stability analysis. The damaged geological strength index of the damaged rock was newly proposed from the relationship between deformation modulus and geological strength index. Also the Hoek-Brown failure criteria of the damaged rock was obtained using the damaged geological strength index. Analysing the tunnel stability with the consideration of the blast-induced damage of remaining rock, it was found that the extend of plastic zone and deformation increased compared to the undamaged rock. Therefore the short-term or long-term tunnel stability will be threatened when the rock damage from blasting is ignored in the tunnel stability analysis.

• Archives of Hand and Microsurgery
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• v.23 no.4
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• pp.306-312
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• 2018

The temporal branch of the facial nerve is particularly vulnerable to traumatic injuries due to its anatomic location, which often causes severe aesthetic and functional loss in the patient. Moreover, a chronic injury with nerve defect is more difficult to treat compared to acute injury, because it usually needs an additional procedure such as a nerve graft surgical procedure. This case shows a male patient who had a divided temporal branch of the facial nerve one month after an injury. We successfully grafted the split sural nerve and showed a good aesthetic, functional recovery for the patient.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.2
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• pp.129-136
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• 2017

This study aims to assess the damage tolerance of the wing structure of aged aircraft with long-term service through the fatigue crack growth analysis and tests. For the fatigue-critical locations (FCL) W2 and W4 in the wing structure, the fatigue stress spectrum was derived based on a previous study. Thereafter, a crack propagation analysis for the FCLs was conducted using the commercial software $NASGRO^{TM}$. The algorithm for the fatigue stress spectrum was verified. Fatigue crack growth tests were then performed for two types of specimens: Type #1 was extracted from the wing structure of aged aircraft, and Type #2 was made of the same material as the wing structure. By comparing the experimental results of these specimens, we assessed the damage tolerance of the wing structure of aged aircraft with service time.

• Journal of Korean Society of Steel Construction
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• v.21 no.3
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• pp.301-310
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• 2009

Steel has been widely used as a material in temporary structures. Corrosion attack often reduces the long-term durability of temporary steel members that are not protected from corrosion. In designing temporary steel structures, it is difficult to evaluate their long-term durability, since the thickness loss of steel members is not clear. In this study, laboratory and field exposure corrosion tests were performed on structural steel plate specimens, and the loss of thickness of specimens that were exposed to a subway construction site for 11 months and of specimens that were exposed to environments with controlled humidity and calcium chloride for six months were measured. Finally, a thickness loss equation was formulated based on the environmental conditions and the testing periods.

• Journal of the Korea Institute of Building Construction
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• v.11 no.2
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• pp.189-199
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• 2011

Installation of a proper root barrier in a green roof system is very important in order to protect the concrete slab of roof and the root penetration in the waterproofing layer. To select the proper root barrier materials and methods, it is necessary to understand the environmental conditions affecting the waterproofing-root barrier system in green roof construction site. Therefore, we suggested as the environmental performance indexes four kinds of performance requirements; root penetration, chemical attack by chemical agent or fertilizer, load impact by soil depth and size of plant, and water pressure. The related four test methods were suggested for the inspection of these performance indexes. In this research, we could suggest for kinds of test methods as standard test methods to evaluate the environmental performance of waterproofing-root barrier for greening roof system.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.533-536
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• 2003

Tn improve the quality in apartment houses, it has regarded one of the most important steps as systematic maintenance. Also, repair and long-term maintenance have played an important role in maintenance of the rental apartment. Moreover, the historical data which come from these works have functioned as preventive maintenance in inspection and references in repair and long-term maintenance. To sum up, it would be necessary to get rid of the factors of dispute from sharing a variety of data among occupants, superintendents, and proprietors. Futhermore, it would be possible to show the management methods of repair and long-term maintenance historical data.

• Journal of the Korean Arthroscopy Society
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• v.4 no.2
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• pp.117-122
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• 2000

Purpose : To compare the mid term with long term follow up results of the anterior cruciate ligament(ACL)> reconstruction using patellar tendon. Materials and Methods : Seventy-six cases, which could be followed up more than 2 years were included in this study. They were classified into two groups, mid-term group(41 cases) with mean follow-up periods of 2 years and 10 months and long-term group(35 cases) off years and 6 months. Clinical and radiological results and peripatellar complications were evaluated & compared. Results . There was no statistically significant difference in radiological finding and anterior instability between two groups. However, the incidence of anterior knee pain, paresthesia at incision site, kneeling pain, crepitus and quadriceps weakness was lower in long-term group than in mid-term group. Conclusion : ACL reconstruction using patellar tendon graft could successfully restone the stability of knee joint, but there are some complications in donor site and patellofemoral joint. However this complications were gradually decreased with long term follow-up.

• Korean Journal of Bronchoesophagology
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• v.2 no.1
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• pp.19-28
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• 1996

이상에서 고찰한 위식도역류의 병태를 간략히 요약하면 다음과 같다. 위액에는 염산, 펩신, 담즙산과 췌효소등을 포함하고 있어 역류된 위액은 상부 기관식도관에 자극을 주거나 손상을 줄 수 있으며 개개인의 점막 상피의 저항도와 적절한 타액의 분비는 위액에 의한 손상의 정도를 결정하는 중요한 요소로 알려져 있다. 위식도역류로 인한 많은 증상이나 소견은 두가지의 기전으로 나타나서 첫째, 역류된 위액이 직접 조직에 영향을 주거나 둘째, 간접적으로 식도 하부에 분포된 미주신경에 의한 연관자극에 의해 일어나는데 위식도역류의 증상 중 두부, 경부, 심장 및 폐장의 증상은 이들 장기에 미주신경의 일부가 같이 분포하여 일어나는 간접적인 기전이다. 하부식도괄약근(lower esophageal sphincter)의 기능은 역류를 막는 가장 중요한 요소로 알려져 있어 간헐적으로 하부식도 괄약근의 압력이 떨어지면 역류가 일어나게 된다. 정상적인 식도의 연동운동은 식도에 역류된 위내용물을 위로 제거되는데 중요하며 위식도역류 환자에서 흔히 연동운동이 저하되거나 비정상적인 연동운동을 관찰할 수 있다. 또한 위내용물이 소장으로 비워지는 시간이 연장되어 위내용물이 위내에 축적되는 것도 위식도역류의 원인의 하나로 생각된다. 이러한 위식도역류의 병태를 연구하는 것은 이 질환의 이해에 도움을 줄 것으로 생각된다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.438-441
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• 2009

휨강성이 작은 바닥시스템인 플랫 플레이트 구조는 응력조건 뿐만 아니라 사용성조건에 의하여 구조적 성능이 결정될 수 있으며, 특히 과도한 시공 하중의 작용은 시공 중 안전성에 대한 단기적인 손상 뿐만 아니라 사용성에 관련된 장기적인 손상을 발생시킬 수 있다. 이러한 플랫 플레이트의 시공하중은 동바리지지 층 수, 시공주기, 슬래브 콘크리트의 재료적인 강성 뿐만 아니라, 동바리의 강성과 슬래브에 발생하는 균열에 의한 영향에 의하여 결정된다. 본 논문에서는 다양한 설계조건에 대한 해석연구를 통하여, 동바리-슬래브의 강성비 변화 및 콘크리트 균열에 의한 단면강성저하가 슬래브들 간의 하중 분포에 미치는 영향을 분석하고, 이러한 동바리 강성 및 슬래브 균열의 영향을 고려한 시공하중 산정법을 제안한다.

• Magazine of the Korean Society of Hazard Mitigation
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• v.11 no.1
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• pp.95-98
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• 2011

최근 국내에서 사회기반시설물에 대한 안전관리 네트워크 통합시스템 구축을 위한 국가핵심과제가 진행되고 있다. 본 연구에서는, 위 과제의 일환으로 진행 중인 철도교량의 구조건전성 모니터링 시스템 구축 및 운용에 대하여 기술하였다. 효율적인 철도교량 모니터링 시스템 구축을 위하여 다양한 종류의 스마트센서가 적용되었으며, 웹 기반의 네트워킹을 통해 외부에서 모니터링 시스템을 원격으로 접속, 제어 할 수 있도록 하였다. 철도교량의 국부 손상을 모니터링 하기 위해 압전센서를 활용한 무선 임피던스 노드를 적용하였고, 구조물 전체의 거동 분석을 위하여 가속도 센서 및 광섬유 센서를 적용하였다. 구조물의 장기 계측을 통한 철도 주행 및 외부 환경에 따른 거동 분석을 수행하였으며, 손상 평가를 위한 신호처리 알고리즘이 적용되었다.