• Journal of the Society of Disaster Information
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• v.7 no.3
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• pp.171-180
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• 2011

As a great earthquake hit east Japan recently, the interests for the necessity of earthquake resistant design and earthquake resistance ability of existent structures are much increased. The damage or collapse of a bridge, as a social overhead capital structure affects socially and economically. Thus the evaluation of earthquake resistance ability of these structures is very important. The reviewing methods for earthquake resistance ability are mostly deterministic. Although the deterministic methods are fit for the evaluation of safety of each member, they are not practical for the whole structure. For the evaluation of structural safety for earthquake, the method for the evaluation of fragility or damage is needed for some stages of damage. In this paper, fragility curves of steel box bridge using RFPB bearing for PGA, PGV, SA, SV, SI are constructed, and these are compared with the cases of FPB.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.1
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• pp.165-174
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• 2010

In this paper, a two-phase structural health monitoring system using acceleration response signatures are presented to firstly alarm the change in structural condition and to secondly detect the changed location for full-scale concrete girder bridges. Firstly, Mihocheon Bridge which is a two-span continuous concrete girder bridge is selected as the target structure. The dynamic response features of Mihocheon Bridge are extracted by forced vibration test using bowling ball. Secondly, the damage alarming occurrence and the damage localization techniques are selected to design two-phase structural health monitoring system for Mihocheon Bridge. As the damage alarming techniques, auto-regressive model using time-domain signatures, correlation coefficient of frequency response function and frequency response ratio assurance criterion are selected. As the damage localization technique, modal strain energy-based damage index method is selected. Finally, the feasibility of two-phase structural health monitoring systems is evaluated from static loading tests using a dump truck.

• Journal of Korean Tunnelling and Underground Space Association
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• v.18 no.2
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• pp.119-128
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• 2016

In a performance-based design, the structural safety is estimated from pre-defined damage states and corresponding damage indices. Both damage states and damage indices are well defined for above-ground structures, but very limited studies have been performed on underground structures. In this study, we define the damage states and damage indices of a cut-and-cover box tunnel which is one of typical structures used in metro systems, under a seismic excitation from a series of inelastic frame analyses. Three damage states are defined in terms of the number of plastic hinges that develop within the structure. The damage index is defined as the ratio of the elastic moment to the yield moment. Through use of the proposed index, the inelastic behavior and failure mechanism of box tunnels can be simulated and predicted through elastic analysis. In addition, the damage indices are linked to free-field shear strains. Because the free-field shear strain can be easily calculated from a 1D site response analysis, the proposed method can be readily used in practice. Further studies are needed to determine the range of shear strains and associated uncertainties for various types of tunnels and site profiles. However, the inter-linked platform of damage state - damage index - shear wave velocity - shear strain provides a novel approach for estimating the inelastic response of tunnels, and can be widely used in practice for seismic designs.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1A
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• pp.61-73
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• 2009

In this paper, hybrid health monitoring techniques using acceleration-impedance features are newly proposed to detect two damage-type in steel plate-girder bridges, which are girder's stiffness-loss and support perturbation. The hybrid techniques mainly consists of three sequential phases: 1) to alarm the occurrence of damage in global manner, 2) to classify the alarmed damage into subsystems of the structure, and 3) to estimate the classified damage in detail using methods suitable for the subsystems. In the first phase, the global occurrence of damage is alarmed by monitoring changes in acceleration features. In the second phase, the alarmed damage is classified into subsystems by recognizing patterns of impedance features. In the final phase, the location and the extent of damage are estimated by using modal strain energy-based damage index method and root mean square deviation (RMSD) method. The feasibility of the proposed hybrid technique is evaluated on a laboratory-scaled steel plate-girder bridge model for which hybrid acceleration-impedance signatures were measured for several damage scenarios. Also, the effect of temperature on the accuracy of the impedance-based damage monitoring results are experimentally examined from combined scenarios of support damage cases and temperature changes.

• Journal of Nutrition and Health
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• v.50 no.1
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• pp.10-24
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• 2017

Purpose: GST (glutathione S-transferase) M1 and T1 gene polymorphisms are known to affect antioxidant levels. This study was carried out to evaluate genetic susceptibility by measuring the effect of DNA damage reduction in the Korean diet by vegetable food according to GST gene polymorphisms using the ex vivo method with human lymphocytes. Methods: Vegetable foods in the Korean diet based the results of the KNHANES V-2 (2011) were classified into 10 food groups. A total of 84 foods, which constituted more than 1% of the total intake in each food group, were finally designated as a vegetable food in the Korean diet. The Korean diet applied in this study is the standard one-week meals for Koreans (2,000 Kcal/day) suggested by the 2010 Dietary Reference Intakes for Koreans. Ex vivo DNA damage in human lymphocytes was assessed using comet assay. Results: In the Korean food group, the DNA damage protective effect of GSTM1 and GSTT1 was found to be greater in mutant type and wild-type, respectively. and the DNA damage protective effect according to the combined genotype of GSTM1 and GSTT1 was different depending on the food group. On the other hand, in Korean Diet, the DNA damage protective effect appeared to be larger in GSTM1 wild-type than in mutant type and was found to not be affected by GSTT1 genotype. Conclusion: These results can be used as basic data to demonstrate the superiority of the antioxidant function of Korean dietary patterns and food groups. Furthermore, it may be a starting point to begin research on customized antioxidant nutrition according to individual genes.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1A
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• pp.115-123
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• 2008

The performance prediction of fiber-reinforced composites has attracted engineer's attention in many fields, and the various theoretical and numerical methods have been proposed to predict the behavior of the fiber-reinforced composites. An evolutionary damage model for progressive interfacial debonding between circular fibers and the matrix is newly incorporated into the micromechanics-based elastoplastic model proposed by Ju and Zhang (2001) in this framework. Using the proposed model, a series of numerical simulations are conducted to illustrate the elastoplastic behavior and evolutionary damage of the framework. Furthermore, the influence of the evolutionary interfacial debonding on the behavior of the composites is investigated by comparing it with the result of a stationary damage model.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2003.05a
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• pp.48-53
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• 2003

최근 기존 암거구조물에 하수관로 등 추가적인 관로의 설치에 의해 암거 구조물이 손상을 입는 경우가 종종 발생되고 있으나, 현장여건상 이에 대한 구조적 안전성의 검토가 미비한 채 시공이 이루어지는 경우가 많다. 이에 본 연구에서는 기존 암거의 상단부에 흄관이 관통하였을 경우 block-out된 암거구조물의 구조적 거동을 검토하기 위하여, 암거구조물의 손상 인접부위의 종방향 및 횡방향 휨모멘트를 구조해석에 의해 산출하고, 이들 구조해석 결과에 의해 block-out된 암거의 손상 인접부위에 대한 구조안전성 검토를 수행하였다.(중략)

• Science of Emotion and Sensibility
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• v.7 no.2
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• pp.179-186
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• 2004

Acute spinal cord injury can produce neurologic injury with many physical, psychological and social ramifications. It has been shown that two separate components combine to produce neurologic damage in acute spinal cord injury : the primary and secondary injuries. The primary mediators of spinal cord injury include the actual mechanical tissue disruption which is a passive process that occurs immediately following the trauma. A secondary injury cascade follows which appears mediated by cellular and molecular processes working through complex mechanisms. Both the primary and secondary injury cascades produce cell death both in neuronal and supporting cell tissues. Recovery from central nervous system(CNS) disorders is hindered by the limited ability of the vertebrate CNS to regenerate injured cells, replace damaged myelin sheath, and re-establish functional neuronal connections. Of many CNS disorders including multiple sclerosis, stroke, and other trauma, spinal cord injury is one of the important diseases because of the direct association with the functional loss of the body. Previous studies suggest that substantial recovery of function might be achieved through regeneration of lost neuronal cells and remyelination of intact axon in spinal cord injury which is occurred frequently. As a therapeutic approach in spinal cord injury, recently, cell transplantation provides a potential solution for the treatment of spinal cord injury. This review describes the characteristics of spinal cord injury and presents some evidence supporting functional recovery after cell transplantation following spinal cord injury.

• Tuberculosis and Respiratory Diseases
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• v.60 no.1
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• pp.49-56
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• 2006

배경 : 급성 폐손상은 폐내, 외의 원인질환들에 의해 폐포-모세혈관의 투과성이 증가하며, 폐부종에 의해 급성 저산소성 호흡곤란이 유발되는 증후군이다. 헤파린은 항응고작용 외에 자체적으로 항염증효과를 가지고 있으나, 염증성질환에 헤파린을 투여하면 출혈성 합병증이 발생하기 때문에 실제로 임상에서 이용하는데 제약이 있다. 하지만 헤파린에서 2-O와 3-O sulfate를 제거하면, 항응고 효과가 제거되고 항염증효과는 지니고 있는 비항응고성 헤파린 (nonanticoagulant heparin)으로 변화한다. 본 연구에서는 흰쥐에게 내독소 (LPS)를 투여하거나, 출혈성 쇼크를 일으켜서 유발된 급성폐손상에서 비항응고성 헤파린의 치료효과를 살펴보았다. 방법 : 각 군당 5 마리 이상의 흰쥐 (Balb/c mouse)를 이용하였다. 미정맥 (tail vein)을 통해 생리식염수 또는 비항응고성 헤파린 (50 mg/kg)을 투여한 직후에 내독소를 복강으로 투여하거나 (1 mg/kg), 심장천자를 통해 총 혈액의 1/3 정도로 제거하여 출혈성 쇼크를 유도하여 급성폐손상을 유발하였다. 내독소 투여 또는 출혈성 쇼크 유발 1 시간 후에 흰쥐를 희생시키고 폐를 적출하였고, 폐의 염증성 변화는 사이토카인 ($TNF-{\alpha}$, MIP-2, $IL-1{\beta}$)을 측정하여 살펴보았고, 폐손상의 정도는 myeloperoxidase (MPO) assay와 wet-to-dry weight ratio를 측정하여 알아보았다. 결 과 : 내독소를 투여한 흰쥐의 폐에서 대조군의 폐에 비해 사이토카인의 발현이 증가하고 ($TNF-{\alpha}$; $196.1{\pm}10.8$ vs $83.7{\pm}18.4pg/ml$, MIP-2; $3,000{\pm}725$ vs $187{\pm}26pg/ml$, $IL-1{\beta}$; $6,500{\pm}1167$ vs $266{\pm}25pg/ml$, p<0.05, respectively), 폐의 MPO 활성이 증가하였다 ($27.9{\pm}6.2$ vs $10.5{\pm}2.3U/g$ of lung protein, p<0.05). 출혈성 쇼크를 일으킨 흰쥐의 폐에서 대조군의 폐에 비해 사이토카인의 발현은 증가되지 않았으나, MPO 발현은 증가되었다 ($16.5{\pm}3.2$ vs $10.5{\pm}2.3U/g$ of lung protein, p<0.05). 내독소 투여 또는 출혈성 쇼크에 의해 급성폐손상이 유발된 흰쥐에서 생리적 식염수를 투여하거나 비항응고성 헤파린을 투여한 군 사이에 사이토카인의 발현이나 MPO 활성에 의미있는 차이는 관찰되지 않았다. 결론 : 이상의 결과로 비항응고성 헤파린은 내독소를 투여하거나 출혈성 쇼크를 일으키고 한 시간 뒤에 측정한 흰쥐의 급성폐손상에서 의미있는 치료효과를 보이지 않았다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.8
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• pp.780-788
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• 2009

AE technique was applied to the static structural test of the composite wing structure to evaluate the structural integrity and damage. During the test, strain and displacements measurement technique were used to figure out for static structural strength. AE parameter analysis and source location technique were used to evaluate the internal damage and find out damage source location. Design limit load test, the 1st and 2nd design ultimate load tests and fracture test were performed. Main AE source was detected by an sensor attached on skin near by front lug. Especially, at the 1st design ultimate test, strain and displacements results didn't show internal damage but AE signal presented a phenomenon that the internal damage was formed. At the fracture test, AE activities were very lively, and strain and displacements results showed a tendency that the load path was changed by severe damage. The internal damage initiation load and location were accurately evaluated during the static structural test using AE technique. It is certified from this paper that AE technique is useful technique for evaluation of internal damage at static structural strength test.