• 한국재난정보학회 논문집
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• 제11권1호
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• pp.55-62
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• 2015

본 연구에서는 풍수해보험요율 산정을 위한 전국단위의 내수침수해석 방안을 제시하였다. 제시된 수정 Level-Pool침수해석은 실제 침수피해지역을 반영하고 내수침수 발생 범위를 한정하기 위해 도시계획 용도지역을 고려하였다. 수정 Level-Pool침수해석에 의한 내수침수지역과 풍수해저감종합계획의 내수재해위험지구와 비교를 통해 적용성을 검토한 결과 기존 Level-Pool침수해석과 비교하여 내수침수지역이 내수재해위험지구를 더 정확하게 재현하는 것으로 나타났다. 따라서 전국단위의 내수침수위험지역을 해석함에 있어서는 본 연구에서 제안한 수정 Level-Pool침수해석이 활용 가능할 것으로 판단된다.

• Journal of Nutrition and Health
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• 제34권3호
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• pp.299-305
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• 2001

The purpose of this study was to investigate the effects of catechin on the changes of microsomal mixed function oxidase(MFO) system and oxidative damage in rat liver exposed to microwave. Sprague-Dawley male rats weighing 200$\pm$10g body weight were randomly assigned to one normal and microwave exposed groups: microwave exposed groups were divided three groups: catechin free diet(MW) group, 0.25% catechin(MW+0.25C) group and 0.5% catechin(MW+0.5C) group to the levels of dietary catechin supplementation. The rats were irradiated with microwave at frequency 2.45GHz for 15 min and then the changes pattern of mixed function oxidase system and oxidative damage were investigated for 16 days. The activity of XOD in MW group was increased from 4 day to 8 days after irradiation, compared to normal group and decreased to the level of normal group 16 days. But catechin supplementation group were maintained to the normal level. The contents of cytochrome P(sub)450 and NADPH cytochrome P(sub)450 reductase activities in liver of MW group was increased from 4 day to 8 day after irradiation, compared to normal group and decreased to the level of normal group at 16 day. But catechin supplementation group were recovered to the normal level. The contents of superoxide radical in liver of MW group was increased 1.28, 1.25, 1.17 fold of normal group at 4,6 and 8 days days after irradiation. respectively, but catechin supplementation group were maintained the normal level. The contents of lipifuscin in liver have a same tendency in superoxide radical contents. These result suggested that the supplementation of catechin have control the mixed function oxidase system and oxidative damage and that may help to recover tissues from microwave damage. (Korean J Nutrition 34(3) : 299~305, 2001)

• Smart Structures and Systems
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• 제12권2호
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• pp.181-207
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• 2013

In this paper, a statistical reference-free real-time damage detection methodology is proposed for detecting joint and member damage of truss bridge structures. For the statistical damage sensitive index (DSI), wavelet packet decomposition (WPD) in conjunction with the log likelihood ratio was suggested. A sensitivity test for selecting a wavelet packet that is most sensitive to damage level was conducted and determination of the level of decomposition was also described. Advantages of the proposed method for applications to real-time health monitoring systems were demonstrated by using the log likelihood ratios instead of likelihood ratios. A laboratory truss bridge structure instrumented with accelerometers and a shaker was used for experimental verification tests of the proposed methodology. The statistical reference-free real-time damage detection algorithm was successfully implemented and verified by detecting three damage types frequently observed in truss bridge structures - such as loss of bolts, loosening of bolts at multiple locations, sectional loss of members - without reference signals from pristine structure. The DSI based on WPD and the log likelihood ratio showed consistent and reliable results under different damage scenarios.

• Earthquakes and Structures
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• 제14권1호
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• pp.73-84
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• 2018

Low cyclic loading tests are conducted on the steel reinforced recycled concrete (SRRC) column-steel (S) beam composite frame joints. This research aims to evaluate the earthquake damage performance of composite frame joints by performing cyclic loading tests on eight specimens. The experimental failure process and failure modes, load-displacement hysteresis curves, characteristic loads and displacements, and ductility of the composite frame joints are presented and analyzed, which shows that the composite frame joints demonstrate good seismic performance. On the basis of this finding, seismic damage performance is examined by using the maximum displacement, energy absorbed in the hysteresis loops and Park-Ang model. However, the result of this analysis is inconsistent with the test failure process. Therefore, this paper proposes a modified Park-Ang seismic damage model that is based on maximum deformation and cumulative energy dissipation, and corrected by combination coefficient ${\alpha}$. Meanwhile, the effects of recycled coarse aggregate (RCA) replacement percentage and axial compression ratio on the seismic damage performance are analyzed comprehensively. Moreover, lateral displacement angle is used as the quantification index of the seismic performance level of joints. Considering the experimental study, the seismic performance level of composite frame joints is divided into five classes of normal use, temporary use, repair after use, life safety and collapse prevention. On this basis, the corresponding relationships among seismic damage degrees, seismic performance level and quantitative index are also established in this paper. The conclusions can provide a reference for the seismic performance design of composite frame joints.

• Annals of Laboratory Medicine
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• 제38권6호
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• pp.524-529
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• 2018

Background: An increase in neutrophil gelatinase-associated lipocalin (NGAL) indicates tubular injury. Diabetic nephropathy causes typical changes in the kidney, characterized by glomerulosclerosis and eventual tubular damage. We validated the usefulness of plasma NGAL (pNGAL) as a biomarker of tubular damage in patients with diabetic nephropathy. Methods: We included 376 patients with diabetes mellitus (260 patients with chronic renal insufficiency who had not received hemodialysis and 116 hemodialyzed due to diabetic nephropathy) and 24 healthy controls. Patients with chronic renal insufficiency were divided into three groups according to urinary albumin excretion (UAE) levels. pNGAL levels were measured using the Triage NGAL test (Alere, San Diego, CA, USA) and were compared between groups. We also examined whether pNGAL level was related to the degree of albuminuria and cystatin C-based glomerular filtration rate (GFR). Results: Mean pNGAL levels of the healthy controls, chronic renal insufficiency patients with diabetes mellitus, and hemodialyzed patients were $61.9{\pm}5.3ng/mL$, $93.4{\pm}71.8ng/mL$, and $1,536.9{\pm}554.9ng/mL$, respectively. pNGAL level increased significantly in patients with severe albuminuria (P <0.001) and had a moderate correlation with the degree of albuminuria (r=0.467; P <0.001) and GFR (r=0.519; P <0.001). Multivariate regression analysis showed that the pNGAL level was associated with tubular damage independent of patient age, sex, and GFR. Conclusions: pNGAL level independently reflects the degree of tubular damage in patients with diabetic nephropathy. Measurement of pNGAL, combined with UAE, would enable simultaneous, highly reliable assessments of tubular damage for such patients.

• 한국지반공학회논문집
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• 제23권10호
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• pp.121-131
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• 2007

본 연구는 흙막이굴착 공사에 의한 지반거동을 평가하여, 구조물의 형상, 위치, 굴착공정 변화등의 다양한 조건과 지반/구조물의 상호작용이 고려된 모형실험을 기본으로 수행하였다. 흙막이굴착에 따른 인접구조물의 손상수준은 구조물의 형상비(L/h), 굴착단계, 이격거리(X) 등에 따라 현저히 다르게 나타남을 확인하였으며, 구조물 중 가장 취약한 구간(BAY)에 따른 평가가 시공초기에 보다 세밀하고 구체적으로 분석되어야 할 것으로 판단된다. 구조물에 발생된 균열의 손상수준을 손상도표에서 평가해 본 결과, 균열손상 수준이 적용된 평가가 각변위와 수평변형율만 적용된 손상수준보다 안전측으로 평가되는 것을 확인할 수 있었다. 그러므로, 각변위와 수평변형율 뿐만 아니라 균열이 고려된 손상평가를 수행하는 것이 보다 바람직할 것으로 판단된다.

• 대한산업공학회지
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• 제7권1호
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• pp.33-36
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• 1981

An equipment is subject to shocks which occur randomly according to a Poisson process. The equipment fails when the total cumulative damage reaches a certain prescribed level. An optimal preventive replacement policy is presented when the level of cumulative damage cannot be checked. Renewal theory is used to obtain the results and a case example is presented.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1999년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring
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• pp.85-92
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• 1999

Blasting induced damage boundary was determined by measuring vibrations adjacent to charging holes. the criterion adopted to define damages is that blasting-induced strains exceeding tension-crack strain level cause damages. The blasting vibrations were measured in terms of acceleration and converted to strains. The tension-crack strain level was determined with tensile strengths and elastic moduli of rock cores. The damage zone was found to be extended radially about 1 meter from the blasthole detonated with 250 to 700 grams of explosives. The comparison of shear wave velocity profiles before and after blasting shows that the damage boundary of 1 meter seems to be reliable.

• 한국국방경영분석학회지
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• 제12권2호
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• pp.22-36
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• 1986

The study is to design optimal aircraft allocation model for sufficing the required level of damage, minimizing attrition cost when the aircrafts attack the enemy's fixed target. When friendly aircraft attacks enemy target, the aircraft will suffer the loss due to the enemy's anti-aircraft weapons and aircraft. For this study, it is required that the probability of target damage by the type of aircraft, level of target damage and attrition cost are computed for the application of this model.

• Geomechanics and Engineering
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• 제18권1호
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• pp.71-83
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• 2019

This investigation presented conventional triaxial and creep-permeability tests on sandstones considering thermally-induced damage (TID). The TID had no visible effects on rock surface color, effective porosity and permeability below $300^{\circ}C$ TID level. The permeability enlarged approximately two orders of magnitude as TID increased to $1000^{\circ}C$ level. TID of $700^{\circ}C$ level was a threshold where the influence of TID on the normalized mass and volume of the specimen can be divided into two linear phases. Moreover, no prominent variations in the deformation moduli and peak strength and strain appeared as TID< $500^{\circ}C$ level. It is interesting that the peak strength increased by 24.3% at $700^{\circ}C$ level but decreased by 11.5% at $1000^{\circ}C$ level. The time-related deformation and steady-state creep rate had positive correlations with creep loading and the TID level, whereas the instantaneous modulus showed the opposite. The strain rates under creep failure stresses raised 1-4 orders of magnitude than those at low-stress levels. The permeability was not only dependent on the TID level but also dependent on creep deformation. The TID resulted in large deformation and complexity of failure pattern for the sandstone.