• Proceedings of the KOR-BRONCHOESO Conference
• /
• 2003.09a
• /
• pp.110-110
• /
• 2003

후두기관외상은 두경부 부위의 다른 외상에 비해 흔하지 않은데, 이는 연골의 유연성과 후두의 가동성, 후두가 하악과 흉골사이에 위치하여 외상시 보호 받게 되는 해부학적 특성에 기인한다. 그러나, 후두는 호흡과 발성에 중요한 기관으로 조기 진단과 정확한 평가, 적절한 치료를 못할 경우 생명을 위협 할 수 있고 삶의 질에 지대한 영향을 줄 수 있다. 이에 저자들은 급성 후두기관손상으로 수술적 치료를 받은 환자를 대상으로 손상 기전 및 임상 양상, 손상부위, 손상 정도 치료 등을 알아보고 향후 치료에 도움을 얻고자 하였다. 1996년부터 2003년까지 급성 후두기관 손상으로 수술적 치료를 받은 10명을 대상으로 후향적으로 조사를 하였다. 손상정도는 Schaefer의 분류를 따랐으며 술후 결과는 발성과 기도유지로 평가하였다. 발성의 경우 수상전과 동일하거나 유사할 경우 성공(good)으로, 수상전과는 다르지만 기능을 하는 경우는 양호(fair)로, 거의 음성이 나지 않거나 알아들을 수 없는 경우 불량(poor)로 분류하였고, 기도유지는 수상전과 동일하거나 유사할 경우 성공(good)으로, 경한 흡인이나 운동 유발성 호흡곤란이 있는 경우(fair)로 발관이 되지 않는 경우를 불량(poor)으로 분류하였다. 남녀 성비는 8대 2였고 30～40대가 4명으로 가장 많았다. 손상의 원인은 둔상인 경우(4예) 교통사고가 2례, cloth line 손상 2례, 관통상(6례)는 모두 칼에 의한 좌상이었다 증상은 피하기종이 9례, 애성이 7례, 호흡 곤란이 6례로 많았으며 손상부위는 갑상연골 골절이 5례(50％), 기도손상과 갑상선 손상이 각각 4례에서 관찰되었다. 그 외에도 윤상 연골 골절과 윤상갑상막 손상 등이 관찰되었다. 또한 점막 손상이 7례에서 관찰되었다. 성대마비는 내원시 4례에서 관찰되었다 치료는 수상 후 조기수술을 시행하였고 수상 부위를 개방하여 손상된 연조직을 일차 봉합하거나, 골절을 정복 고정하였고 3례에서 스텐트를 삽입하였다. 술후 기도유지는 모두 성공적이었고 발성기능은 6례에서 성공(good)적이었고 4례에서 양호(fair)의 결과를 보였다. 양호의 결과를 보인 모든 예가 내원시 성대 움직임의 마비나 저하를 보인 예였다. 급성 후두기관손상환자에서 조기 진단과 적절한 수술적 치료는 환자의 생명을 유지시키고 술후 발성 지능의 보존에 양호한 결과를 보였다.

• Explosives and Blasting
• /
• v.26 no.2
• /
• pp.11-19
• /
• 2008

The development of an excavation damaged zone, EDZ, due to the blasting impact and stress redistribution after excavation, can influence on the long tenn stability, economy, and safety of the underground excavation. In this study, the size and characteristics of an EDZ around an underground research tunnel, which was excavated by controlled blasting, in KAERI were investigated. The results were implemented into the modelling for evaluating the influence of an EDZ on hydro-mechanical behavior of the tunnel. From in situ tests at KURT, it was possible to determine that the size of EDZ was about l.5rn. Goodman jack tests and laboratory tests showed that the rock properties in the EDZ were changed about 50% compared to the rock properties before blasting. The size and property change in the EDZ were implemented to a hydro-mechanical coupling analysis. In the modeling, rock strengths and elastic modulus were assumed to be decreased 50% and. the hydraulic conductivity was increased 1 order. From the analysis, it was possible to see that the displacement was increased while the stress was decreased because of an EDZ. When an EDZ was considered in the model, the tunnel inflow was increased about 20% compared to the case without an EDZ.

• Proceedings of the Korean Society of Disaster Information Conference
• /
• 2022.10a
• /
• pp.347-348
• /
• 2022

본 연구에서는 무인이동체를 활용한 철도교량의 외관조사 점검을 보다 효율적이고 객관성 있게 수행하기 위하여 무인이동체를 통해 촬영된 이미지를 딥러닝 기반 분석기술을 활용하여 손상 자동으로 분석 하기위한 기술을 연구하였다. 철도교량의 외관 손상 중 균열, 콘크리트 박리·박락, 누수, 철근노출에 대한 손상 이미지를 추출하여 딥러닝 분석 모델을 생성하고 학습한 분석 모델을 적용한 시스템을 실제 현장에 적용 테스트를 수행하였으며 학습 구현된 분석모델의 검측 재현율을 검토한 결과 평균 95%이상의 감지성능을 검토할 수 있었다. 개발 제안된 자동손상분석 기술은 기존 육안점검 결과 대비 보다 객관적이고 정밀한 손상 검측이 가능하며 철도 유지관리 분야에서 무인이동체를 활용한 외관조사 업무를 수행함에 있어 기존 대비 객관적인 결과도출과 소요시간, 비용저감이 가능할 것으로 기대된다.

• Journal of the Society of Naval Architects of Korea
• /
• v.37 no.1
• /
• pp.50-59
• /
• 2000

This paper presents a brief outline of dynamic stability of a damaged ship at final stage of flooding in rough beam wind and waves. One degree-of-freedom, roll equation is adopted with effects of flooding water and external forces due to wind and waves, but without effect of sloshing. We discuss the dynamic stability of the damaged ship in terms of capsizing probability based on risk analysis, the method of which was firstly proposed by Umeda et al.[6] to high speed craft in intact condition. As a result, we can evaluate the dynamic stability of the damaged ship in probabilistic manner according to sea state, operating condition and damage situation.

• Explosives and Blasting
• /
• v.28 no.2
• /
• pp.59-68
• /
• 2010

Building demolition and blasting work in urban areas has a possibility which has an effect on the structural stability of nearby structures. In this study, the compressive strength and chemical composition of decrepit concrete materials were estimated by Schmidt rebound test and XRD phase analysis. The damage index of the concrete materials was calculated by measured P-wave velocities. It was revealed that the constituents of the concrete materials affect on the compressive strength. The damage index decreases with increasing compressive strength and decreasing impact energy.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.11 no.3
• /
• pp.159-166
• /
• 2007

This paper evaluates the soundness of structural elements using Wavelet Packet Transform (WPT). WPT is applied to the response acceleration of a framed structure which is subjected to earthquake load to decompose the response acceleration, then the energy of each component is calculated. The first five largest components in energy magnitude among the decomposed components are selected as input to an ANN to identify the damage location and severity. Two nodes in output layer yield damaged element and damage severity respectively. This method successfully evaluates the amount of damage and its location in the structure.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.12 no.1
• /
• pp.175-182
• /
• 2008

In performing a risk analysis of structure for earthquake, it is imperative to identify the vulnerability of structures associated with various stages of damage. And the earthquake resisting capability is needed for structures like bridge. So the damage analysis of bridges with or without isolator for earthquake effects is necessary. In this paper, the risk analysis of seismic isolated LRB bridges considering earthquake effects such as PGA, PGV, SA, SV, and SI is performed using fragility curves to assure the earthquake resisting capability of the structures. And, the stability of fragility curve is investigated with respect to elastic modulus.

• Magazine of the Korea Concrete Institute
• /
• v.7 no.5
• /
• pp.172-178
• /
• 1995

Concrete contains numerous microcracks at initially poured. The growth and propagation of nicrockacsk are believed tc finally incur the faiure of concrete. These processings are understood as a damage. Damage IS represented as a second-order tensor and crack is treated as a con tinuum phenomenon. In this paper, damage is characterized through the effective stress concept together with the hypothesis of elastic energy equivalence, and damage evolution law and constitutive equation of a damage model are derived by using the Helmholtz frte eriergy and the dissipation potential by means of the thermodynamic principles. The constitutive equation of the model includes the effects of elasticity, anisotropic damage and plasticity of concrete. There are two effective tangent stiffness tensors in this model : one is for elastic-darnage and the other for plastic damage. For the verification of the model, finite element analysis was performed for the analysis of concrete subjec:t to uniaxial and biaxial loading and the results obtained were compared with test results.

• Journal of Chest Surgery
• /
• v.34 no.11
• /
• pp.823-830
• /
• 2001

Background: Paraplegia is a serious complication of thoracic or thoracoabdominal aortic operations, which is related to ischemic injury of the spinal cord induced by low perfusion pressure during cross clamping of the aorta. Ischemic preconditioning of heart or brain with reversible sublethal ischemic injury induces resistance to subsequent lethal ischemia. The aim of this study is to investigate whether ischemic tolerance could be induced by the preconditioning of the spinal cord using swine model. Material and Method: The animals were randomly assigned to three groups: sham group(n=3), control group(n=6) and pre-conditioning group(n=8). In the sham group, we performed the left thoracotomy only without any ischemic injury. In the preconditioning group, the swine received reversible spinal cord ischemic injury by aortic clamping for 20 minutes, whereas control group had no previous aortic cross- clamping. Forty-eight hours later, the aorta was clamped for 30 minutes in both groups. Neurological examination was done 24 hours later, then the animals were euthanized for histopathology and malonedialdehyde(MDA) spectrophotometry assay of the spinal cord. Result: Statistically significant difference in neurological outcome was observed between the control and preconditioning groups at 24 hours after ischemic injury. The incidence of paraplegia and severe paresis was 100% in the control group, and 62.5% in the preconditing group(p=0.028). There was no statistically significant difference in histopathology and MDA assay of the ischemic spinal cord between these two groups with borderline statistical difference in MDA assay(p=0.0745). Conclusion: In the present swine study, ischemic preconditioning could induce tolerance against 30 minute ischemic insult of the spinal cord, although the animals did not completely recover(stand-up or walk). We expect that combining this preconditioning with other currently existing protection methods might lead to a synergistic effect, which warrants further investigation.

• Journal of Korean Association for Spatial Structures
• /
• v.4 no.2 s.12
• /
• pp.73-80
• /
• 2004

In this paper, a study of damage detection for 2-Dimensional Truss Structures using the parametric projection filter theorr is presented. Many researchers are interested in inverse problem and one of solution procedures for inverse problems that are very effective is the approach using the filtering algorithm in conjunction with numerical solution methods. In filtering algorithm, the Kalman filtering algorithm is well known and have been applied to many kind of inverse problems. In this paper, the Parametric projection filtering in conjunction with structural analysis is applied to the identification of damages in 2-D truss structures. The natural frequency and modes of damaged truss model are adopted as the measurement data. The effectiveness of proposed method is verified through the numerical examples.