• Structural Engineering and Mechanics
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• v.82 no.4
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• pp.517-542
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• 2022

The effect of mean angle of wind attack on the flutter critical wind speed of two generic bridge deck cross-sections, viz, one closed box type streamlined section (deck-1) and closed box trapezoidal bluff type section with extended flanges/overhangs (deck-2) type of section have been studied using Computational Fluid Dynamics (CFD) based forced vibration simulation method. Owing to the importance of the effect of the amplitude of forcing oscillation on the flutter onset, its effect on the flutter derivatives and flutter onset have been studied, especially at non-zero mean angles of wind attack. The flutter derivatives obtained have been used to evaluate flutter critical wind speeds and flutter index of the deck sections at non-zero mean angles of wind attack studied and the same have been validated with those based on experimental results reported in literature. The value of amplitude of forcing oscillation in torsional degree of freedom for CFD based simulations is suggested to be in the range of 0.5° to 2°, especially for bluff bridge deck sections. Early onset of flutter from numerical simulations, thereby conservative estimate of occurrence of instability has been observed from numerical simulations in case of bluff bridge deck section. The study aids in gaining confidence and the extent of applicability of CFD during early stages of bridge design, especially towards carrying out studies on mean incident wind effects.

• Safety and Health at Work
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• v.13 no.1
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• pp.51-58
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• 2022

Introduction: Previous studies on occupational health focussed predominately on the occurrence of occupational diseases. Relatively few studies have measured how employment is associated with the use of healthcare services. This study investigates the association between employment and the extent and range of healthcare use, such as medical expenditures, of women in South Korea. Methods: We analyze data of the Korean Health Panel, an ongoing longitudinal national representative survey, from 2008 to 2017, to identify the status of economic activity of women by year and age group. We estimate the association between female employment status and medical expenditures by using random effect panel Tobit models. Furthermore, we investigate the association between employment status and the range of healthcare services in biomedicine and traditional Korean medicine (KM) by conducting conditional fixed-effects logistic regression analyses. Results: For women aged between 25 and 65 in 2017, the majority of them were employed or self-employed. (The proportion of employment of self-employment equals 64.80%). In addition, working women spent 11.6% less on healthcare than nonworking women, and self-employment lowered the healthcare expenditure by 13.1%. Neither work nor the type of work is related to the types and range of healthcare service use. Being employed or self-employed is negatively associated with women's expenditure on healthcare. Conclusions: The findings show that employment is associated with less spending on healthcare. They imply that employment has a positive impact on women's health.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.283.2-283.2
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• 2002

Organochlorine pesticides and polychlorinated biphenyls (PCBs) have been used intensively in agriculture and industry for a long time. They belong to a group of contaminants whose occurrence in the environment is a serious concern to environmental chemists and toxicologists due to their resistance to degradation in the environment as well as their potential toxicity. Also. the lipophilic characteristics of these substances are responsible for their ability to bioaccumulate in tissues and organs rich in lipids of men and animals through food chain. Therefore, the measure of the levels of organochlorine pesticides and PCBs in human tissues are good markers in detemining the extent to exposure and evaluating the hazards. This study was preformed to compare concentrations of organochlorine pesticides(${\alpha}-BHC, {\beta}-BHC, {\gamma}-BHC, {\delta}-BHC$, p.p'-DDT,p.p'-DDD,p.p.'-DDE. endrin. dieldrin. aldrin) and seven marker PCBs(PCB nos. 28. 52. 101. 118. 138. 153. 180) in liver. kidney cortex, lung blood and adipose tissue collected at autopsies of 10men and 10 women using gas chromatography equipped with electron capture detector to express the data on a lipid adjusted basis. From the results, the significant differences in the levels of organochlorines of PCBs between sexes, districts where they had lived and ages were also investigated.

• Physical Therapy Korea
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• v.8 no.1
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• pp.89-96
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• 2001

This study addresses the effects of treadmill training on hyperextended knee and cadence in patients with hemiplegia. A single subject research design with multiple baselines across individuals was used for the study. Two patients with hemiplegia participated in the experiment. The experiment consisted of interventions where the patients were asked to ambulate for 15 minutes at a comfortable walking speed on the treadmill with 11% slope grade and were allowed to rest for 10 minutes. Patients, then, were asked to ambulated 20 meters at walkway. The number of occurrences of knee hyperextension and the total number of steps were recorded. The results showed that the occurrence of knee hyperextension decreased by approximately 30% after the first session of the treadmill training and continued to gradually decrease during the following sets of treadmill training. Meanwhile, there was a slight increase in the cadence to a negligible extent. These results suggest that the gait training on the sloped treadmill may be helpful for correcting the knee hyperextension in patients with hemiplegia.

• Journal of the Korean Society of Safety
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• v.20 no.2 s.70
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• pp.119-126
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• 2005

Load bearing structural members in a wide variety of applications accumulate damage over their service life. From a standpoint of both safety and performance, it is desirable to monitor the occurrence, location, and extent of such damage. Structures require complicated element models with a number of degrees of freedom in structural analysis. During experiment much effort and cost is needed for measuring structural parameters. The sparseness and errors of measured data have to be considered during the parameter estimation Of Structures. In this paper we introduces damage identification algorithm by a system identification(S.I) using static and dynamic response. To study the behaviour of the estimators in noisy environment Using Monte Carlo simulation and a data measured perturbation scheme is adopted to investigate the influence of measurement errors on identification results. The assessment result by static and dynamic response were compared, and the efficiency and applicabilities of the proposed algorithm are demonstrated through simulated static and dynamic responses of a truss bridge. The assessment results by each method were compared and we could observe that the 5.1 method is superior to the other conventional methods.

• Journal of the Korea Safety Management & Science
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• v.14 no.2
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• pp.83-89
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• 2012

In this study, FDS fire simulation experiments and measured wind speed by applying the exterior installation portion for blocking the spread of the fire was investigated. As a result, aluminum composite panels installed in the lower and the upper part of the panel to remove all the lower side, and then the maximum wind speed 0.24 m/s and the upper side 0.58 m/s were measured. In the FDS, the measured wind speed difference air currents are approximately 3.7 times in 12 seconds, the occurrence of 17 seconds early moment wind 2.2 m/s was measured from. Before and after the fire occurred in early of the air velocity about 39 seconds was 3.5 times difference. Such air currents caused by the temperature of the building but also by the building height was found. Turbulent flame of fire by expanding the vertical extent of damage become greatly important factor. Therefore, through the exterior installation portion of the block that can delay the spread of fire is expected that this should be taken.

• Journal of Integrative Natural Science
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• v.13 no.1
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• pp.34-40
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• 2020

This study aims to create a model for predicting the number of extinguishment manpower to put out forest fires by taking into account the climate, the situation, and the extent of the damage at the time of the forest fires. Past research has been approached to determine the cause of the forest fire or to predict the occurrence of a forest fire. How to deal with forest fires is also a very important part of how to deal with them, so predicting the number of extinguishment manpower is important. Therefore predicting the number of extinguishment manpower that have been put into the forest fire is something that can be presented as a new perspective. This study presents a model for predicting the number of extinguishment manpower inputs considering the scale of the damage with forest fire on a scale bigger than 0.1 ha as data based on the forest fire annual report(Korea Forest Service; KFS) from 2015 to 2018 using the moderated multiple regression analysis. As a result, weather factors and extinguished time considering the damage show that affect forest fire extinguishment manpower.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.23 no.1
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• pp.37-48
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• 2020

This study was aimed to design core areas applied by the global conservation criteria to promote the public awareness to the protected areas and the value cognition of the Key Biodiversity Areas (KBAs), targeting the Mt Seorak, according to the designation of globally important biodiversity areas. As a method for carrying out this study, the biota were cataloged through literature reviews and field trips. With applied by the Global Red List criteria of the International Union for Conservation of Nature (IUCN), only nine species were categorized in the studied area; plants were classified into six species as follows: Megaleranthis saniculifolia ohwi, Bupleurum euphorbioides Nakai, Hanabusaya asiatica Nakai, Thuja koraiensis Nakai, Leontopodium leiolepis Nakai, Androsace cortusaefolia Nakai, fish was classified one species as follow: Pungitius sinensis Tanaka, and the mammal was classified as two species as follows: Hydropotes inermis, Naemorhedus caudatus. According to the occupation area (EoO, Extent of Occurrence) and Minimum Viable Population(MVP), the size of protected area was 234.56㎢ for plants, 235.07㎢ for mammals, and 0.14㎢ for fish, and the Key Biodiversity Area (KBA) of Mt. Seolak suggested as 286.72㎢.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.224-224
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• 2015

The East Asia monsoon is one of the most complex atmospheric phenomena caused by Land-Sea thermal contrast. It plays essential role in fulfilling the water needs of the region but also poses stern consequences in terms of flooding and droughts. This study analyzed the influence of Global Sea Surface Temperature Anomalies (SSTA) on occurrence of droughts in the East Asia monsoon region ($20^{\circ}N-50^{\circ}N$, $103^{\circ}E-149^{\circ}E$). Standardized Precipitation Index (SPI) was employed to characterize the droughts over the region using 30-year (1978-2007) gridded rainfall dataset at $0.5^{\circ}$ grid resolution. Due to high variability in intensity and spatial extent of monsoon rainfall the East Asia monsoon region was divided into the homogeneous rainfall zones using cluster analysis method. Seven zones were delineated that showed unique rainfall regimes over the region. The influence of SSTA was assessed by using lagged-correlation between global gridded SSTA ($0.2^{\circ}$ grid resolution) and SPI of each zone. Sea regions with potential influence on droughts in different zones were identified based on significant positive and negative correlation between SSTA and SPI with a lag period of 3-month. The results showed that SSTA have the potential to be used as predictor variables for prediction of droughts with a reasonable lead time. The findings of this study will assist to improve the drought prediction over the region.

• Smart Structures and Systems
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• v.12 no.3_4
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• pp.309-325
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• 2013

Environmental and operational variables are inevitable concerns by researchers and engineers when implementing the damage detection algorithm in practical projects, because the change of structural behavior could be masked by the conditions in a large extent. Thus, reliable damage detection methods should have a virtue of immunity from environmental and operational variables. In this paper, the pair cointegration method was presented as a novel way to remove the effect of environmental variables. At the beginning, the concept and procedure of this approach were introduced, and then the theoretical formulation and numerical simulations were put forward to illustrate the feasibility. The jump exceeding the control limit in the residual indicates the occurrence of damage, while the direction and magnitude imply the most potential damage location. In addition, the simulation results show that the proposed method has strong ability to resist the noise.