• Journal of the Korea Institute of Building Construction
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• v.16 no.5
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• pp.437-445
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• 2016

Since typhoon is a critical meteorological disaster, some advanced countries have developed typhoon damage prediction models. However, although South Korea is vulnerable to typhoons, there is still shortage of study in typhoon damage prediction model reflecting the vulnerability of domestic building and features of disaster. Moreover, many studies have been only focused on the characteristics and typhoon and regional characteristics without various influencing factors. Therefore, the objective of this study is to analyze typhoon damage by path and develop to prediction model for building damage ratio by using multiple regression analysis. This study classifies the building damages by typhoon paths to identify influencing factors then the correlation analysis is conducted between building damage ratio and their factors. In addition, a multiple regression analysis is applied to develop a typhoon damage prediction model. Four categories; typhoon information, geography, construction environment, and socio-economy, are used as the independent variables. The results of this study will be used as fundamental material for the typhoon damage prediction model development of South Korea.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.09a
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• pp.295-302
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• 2003

A quantitative approach for the retrofit prioritization of bridges is developed based on the damage risk of seismic vulnerable components. In the developed approach, seismic damage risk is estimated in the probabilistic perspectives with an analytical bridge model, which can consider various phenomena found in the seismic behaviors of girder-type bridges and damage models of various vulnerable components. Based on the total cost due to failure of structural components, weighting factors are proposed. Finally, the ranking index and retrofit priority of bridges are estimated from the overall damage risk and weighting factors of bridges. As a result, the retrofit priority of four PSC girder bridges is evaluated by using the proposed approach. The vulnerable components in need of seismic retrofit are selected accordingly. From simulated results, the validity of the proposed approach is verified by comparison with the existing approach. In addition, the proposed approach is found to be appropriate in evaluating the priority of existing bridges.

• Journal of the Korean Geosynthetics Society
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• v.6 no.4
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• pp.29-37
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• 2007

Reduction Factor for Installation Damage required for calculation of design strength of geogrid used in MSEW(mechanically stabilized earth wall) design is usually obtained in the field test simulating real construction condition. However, damages occurred in geogrid during backfill work are influenced by many factors such as polymer types, unit weight per area, backfill construction method and gradation of backfill material and field test considering these factors demands lots of time and costs. In this study, factors affecting installation damage are analyzed and empirical method for evaluating reduction factor for installation damage using maximum particle size in backfill material is suggested.

• Journal of Nutrition and Health
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• v.27 no.7
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• pp.740-751
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• 1994

Sister chromatid exchanges(SCE) in peripheral lymphocytes is recently used as a biomarker for increased cytogenetic damage in smokers. The purpose of the investigation was to determine if there were any relationships between dietary factors and their DNA damage as measured by SCE test in a group of 62 male cigarette smokers and 36 non-smokers. As expected, smokers as compared with non-smokers had high SCE levels (10.59$\pm$0.21 versus 9.23$\pm$0.17 SCE/lymphocytes ; p<0.05). No significant relationships were observed between SCEs and age in smokers and non-smokers. In smokers, SCEs were negatively correlated with egg frequency score(r=-0.336) and total food frequency scores(r=-0.283). In non-smokers, SCEs were positively correlated with white vegetable frequency score(r=0.333) and instant food frequency score(r=0.382). There was a positive association between SCEs and the history of coffee intake of smokers(r=0.318). SCE frequency was not influenced by any other dietary factors considered ; dietary diversity and quality scores, alcohol consumption, use of processed foods and intake of burned food. No significant relationships were found between SCEs and serum cholesterol or other hematological parameters of the subjects. These results indicate that increased egg frequency score, total food frequency score which reflects dietary quality, and decreased coffee intake may reduce cancer risk by preventing smoking-induced DNA damage as reflected by sister chromatid exchanges in human lymphocytes.

• Earthquakes and Structures
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• v.26 no.2
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• pp.131-147
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• 2024

Damage caused by an earthquake depends on not just the intensity of an earthquake but also the region-specific construction practices. Past earthquakes in Asian countries have highlighted inadequate construction practices, which caused huge life and property losses, indicating the severe need to strengthen existing structures. Strengthening activities shall be proposed as per the proposed weighting factors, first at the higher weighted members to increase the capacity of the building immediately and thereafter, the other members. Through this study on gravity load-designed (GLD) buildings, relative weights are assigned to each storey and exterior and interior columns within a storey based on their contribution to the energy dissipation capacity of the building. The numerical study is conducted on mid-rise archetype GLD buildings, i.e., 4, 6, 8, and 10 stories with variable storey heights, in the high seismic zones. Non-linear static analysis is performed to compute weights based on energy dissipation capacities. The results obtained are verified with the non-linear time history analysis of 4 GLD buildings. It was observed that exterior columns have higher weightage in the energy dissipation capacity of the building than interior columns up to a certain building height. The damage in stories is distributed in a convex to concave parabolic shape from bottom to top as building height increases, and the maxima location of the parabola shifts from bottom to middle stories. Relative weighting factors are assigned as per the damage contribution. And the sequence for strengthening activities is proposed as per the computed weighting factors in descending order for regular RCC buildings. Therefore, proposals made in the study would increase the efficacy of strengthening activities.

• Journal of Ecology and Environment
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• v.43 no.4
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• pp.364-375
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• 2019

Background: Ecologists continue to investigate the factors that potentially affect the pattern and magnitude of tree damage during catastrophic windstorms in forests. However, there still is a paucity of research on which trees are more vulnerable to direct damage by winds rather than being knocked down by the fall of another tree. We evaluated this question in a mixed hardwood-softwood forest within the Big Thicket National Preserve (BTNP) of southeast Texas, USA, which was substantially impacted by Hurricane Rita in September 2005. Results: We showed that multiple factors, including tree height, shade-tolerance, height-to-diameter ratio, and neighborhood density (i.e., pre-Rita stem distribution) significantly explained the susceptibility of trees to direct storm damage. We also found that no single factor had pervasive importance over the others and, instead, that all factors were tightly intertwined in a complex way, such that they often complemented each other, and that they contributed simultaneously to the overall susceptibility to and patterns of windstorm damage in the BTNP. Conclusions: Directly damaged trees greatly influence the forest by causing secondary damage to other trees. We propose that directly and indirectly damaged (or susceptible) trees should be considered separately when assessing or predicting the impact of windstorms on a forest ecosystem; to better predict the pathways of community structure reorganization and guide forest management and conservation practices. Forest managers are recommended to adopt a holistic view that considers and combines various components of the forest ecosystem when establishing strategies for mitigating the impact of catastrophic winds.

• Korea Trade Review
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• v.45 no.6
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• pp.45-54
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• 2020

Occurrence of accidents at a container terminal results in casualties and damages of equipments which are involved in the accidents, and affects the terminal operation. Therefore, analyzing factors affecting occurrence of accidents at a container terminal is important for efficient operation of the terminal. Most of existing studies analyzing factors of accidents have performed in a land transportation field. And most of existing studies in a maritime field have focused on developing risk assessment methods, rather than identifying factors of accidents. This study aims to analyze the factors affecting the damage level which was resulted from accidents at a container terminal in Busan, Korea. After a basic statistical analysis of the accident dataset which was occurred in the terminal, a linear regression model is applied to identify the factors which affect the damage level resulted from the accident. As a result of analysis, it is found that the more number of equipments, facilities and containers damaged from the accidents positively affect the damage level from the accidents, as well as dozing during working. The results of this study are expected to be a basic for developing safety management.

• Journal of architectural history
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• v.22 no.6
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• pp.47-58
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• 2013

The purpose of this study is to analyze the cause of damage to the three storied stone pagoda of Bulguksa temple in GyeongJu. This report is attempted to making reinforcement and conservation plan through investigating and analyzing the cause of damage to that. The damage is caused by occurring of stress, degrading of stone strength, changing of underground soil structure, natural disasters and so on. Compressive stress, shear stress, bending stress and lateral pressure affected to the pagoda since built up. Ultrasonic examination data tells the strength of the stone. According to this result, strength of the stereobate stone materials is enough to support the weight of the upper ones. But we could found many other factors of the damage could consider, for example the problems occurred on building the pagoda construction and the weakness of the stone material(soft rock). And many environmental factors being changed in soil structure(subsidence of soil and degradation of bearing power of soil and freezing and melting of soil) can be seen as the cause of the damage. Natural disasters like earthquake, lightning and heavy rain were also thought to give direct impact to the damage. At last Concentration of compressive stress caused the crack and exfoliation on the stone materials and shear stress, bending stress and lateral pressure were main causes of the stereobate stone materials shearing.

• Structural Engineering and Mechanics
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• v.65 no.1
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• pp.43-51
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• 2018

Structural modal parameters i.e. natural frequencies, damping ratios and mode shapes are dynamic features obtained either by measuring the vibration responses of a structure or by means of finite elements models. Over the past two decades, modal parameters have been used to detect damage in structures by observing its variations over time. However, such variations can also be caused by environmental factors such as humidity, wind and, more importantly, temperature. In so doing, the use of modal parameters as damage indicators can be seriously compromised if these effects are not properly tackled. Many researchers around the world have found numerous methods to mitigate the influence of such environmental factors from modal parameters and many advanced damage indicators have been developed and proposed to improve the reliability of structural health monitoring. In this paper, several vibration tests are performed on a simply supported steel beam subjected to different damage scenarios and temperature conditions, aiming to describe the variation in modal parameters due to temperature changes. Moreover, four statistical methodologies are proposed to identify damage. Results show a slightly linear decrease in the modal parameters due to temperature increase, although it is not possible to establish an empirical equation to describe this tendency.

• Journal of the Korean Geosynthetics Society
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• v.4 no.4
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• pp.23-37
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• 2005

The factors affecting the long-term design strength of geogrid can be classified into factors on creep deformation, installation damage, temperature, chemical degradation and biological degradation. Especially, creep deformation and installation damage are considered as main factors to determine the long-term design strength of geogrid. Current practice in the design of a reinforced soil structures is to calculate the long-term design strength of a geosynthetic reinforcement damaged during installation by multiplying the two partial safety factors, $RF_{ID}$ and $RF_{CR}$. This method assumes that there is no evaluation of synergy effect between installation damage and creep deformation of geogrids. This paper describes the results of a series of experimental study, which are carried out to assess the combined effect of the installation damage and the creep deformation for the long-term design strength of geogrid reinforcements. A series of field tests was carried out to assess installation damage of various geogrids with respect to different fill materials, and then creep tests are conducted to evaluate the creep deformation of both undamaged and damaged geogrids. The results indicated that the tensile strength reduction factors, RF, considering the combined effect between the installation damage and the creep deformation is less than that calculated by the current design method.