• Korean Journal of Construction Engineering and Management
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• v.18 no.1
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• pp.37-47
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• 2017

The proportion of elderly people over 50 years old in the total population of Korea increased from 29.2% in 2010 to 34.8% in 2015. As a result, the proportion of construction workers over 50 years old compared to the total construction workers increased from 20.1% in 2010 to 27.0% in 2015. In this aging society, the construction industry has faithfully carried out the business objectives and budget execution of measures to prevent disasters against elderly workers, but there was a limit to the fundamental prevention of disasters. Because the countermeasures for the prevention of construction disaster are considered on all ages rather than elderly workers. This study investigates the safety and health status of elderly workers at construction sites and suggests the plans to reduce disaster. In particular, to reduce disasters of rapidly growing elderly workers, the authors reviewed the related literature and safety regulations, statistics on the causes of industrial accidents, statistics on the status of industrial accidents, and applied to 3,549 workers who participated directly in the construction activities. The authors surveyed the actual situation of safety and health, presented the comprehensive disaster reduction measures by analyzing the current status and problems of disaster prevention projects. If the countermeasures proposed in this paper can be reflected in the actual policy, it is expected that the countermeasures will be possible to reduce the disaster of the elderly workers at the construction site, which is gradually increasing.

• Geophysics and Geophysical Exploration
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• v.10 no.4
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• pp.353-360
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• 2007

We practiced fresh water injection test to identify its applibility as a method of seawater intrusion mitigation technique, and monitored the change of borehole fluid conductivity and the behavior of injected fresh water using borehole multichannel electrical conductivity monitoring and well-logging, and DC resistivity and SP monitoring at the surface. Well-logging and multichannel EC monitoring showed the decrease of fluid conductivity due to fresh water injection. We note that such an injection effect lasts more than several month which means the applibility of fresh water injection as a seawater intrusion control technique. Although SP monitoring did not show meaningful results because of weather condition during monitoring and the defects of electrodes due to long operation time, DC resistivity monitoring showed its effectiveness and applicability as a monitoring and assessment techniques of injection test by means of imaging the behavior and the front of fresh water body in terms of the increase of resistivity with reasonable resolution. In conclusion, we note that geophysical techniques can be an effective method of monitoring and evaluation of fresh water injection test, and expect that fresh water injection may be an practical method for the mitigation of seawater intrusion when applied with optimal design of injection well distribution and injection rate based on geophysical evaluation.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.2
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• pp.139-147
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• 2008

More precise estimation of the bed change, primary cause of flood damage, has been recognized significant for designs of levees and other river facilities. In this study, the long-term bed change was examined as the application of the relatively new Surface-water Modeling System (SMS) Model because there has not been broad verification of the model empirically on river of South Korea. This 2-dimensional model was used to examine the bed change of Pochon Stream Basin, a tributary of Imjin River, where heavy rain damages annually occur. First, in order to verify the model, the simulating period was set from 1986 to 1998 because of the existence of the field measurements. Cross sectional field measurements of 1986 were used for the initial condition and output were compared and analyzed with the observed cross sectional data in 1998. As the results of the verification, the comparison in lateral and streamwise bed level between results from the model and the field measurements showed a reasonable agreement except for the some cases of local scours. However, in terms of the quantitative comparison, the change of the bed elevations for each cross section for 1998 was rather underestimated than that of the field measurements.

• Journal of Environmental Impact Assessment
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• v.29 no.6
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• pp.453-466
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• 2020

The addition and evaluation of health impact items in Environmental Impact Assessment document are written in hygiene and public health items only for specific development projects and are being reviewed. However, after the publication of the evaluation manual on the addition and evaluation of health impact items in 2011, there is a demand for continuous methodology and improvement plans despite partial improvement. Therefore, in order to propose a methodological improvement of the evaluation manual, this technical paper identified detailed improvement requirements based on the consultation opinions on hygiene and public health items, and investigated and suggested ways to solve this problem by reviewing the contents of the research so far. As for the improvement requirements, the contents related to mitigation plan, post management, effect prediction, assessment, and present-condition investigation were presented in Environmental Impact Assessment documents for the entire development project at a frequency of 93%, 85%, 80%, 74%, and 67%, respectively. Particularly, the detailed improvement requirements related to mitigation plan consisted of an establishment direction and a management of development project. Considering the current evaluation manual and the frequency of improvement requirements, this paper proposed concrete methods or improvement plans for major methodologies for each classification of hygiene and public health items. Furthermore, a comprehensive evaluation methodology related to whether a project is implemented was proposed, which is not provided in the current assessment manual.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.25 no.6
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• pp.51-64
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• 2022

Along with the urbanization, the risk of urban flooding due to climate change is increasing. Flood regulation, one of the ecosystem services, is implemented in the different level of function of flood risk mitigation by the type of ecosystem such as forests, arable land, wetlands etc. Land use changes due to development pressures have become an important factor in increasing the vulnerability by flash flood. This study has conducted evaluating the urban flood regulation service using InVEST UFRM(Urban Flood Risk Model). As a result of the simulation, the potential water retention by ecosystem type in the event of a flash flood according to RCP 4.5(10 year frequency) scenario was 1,569,611 tons in urbanized/dried areas, 907,706 tons in agricultural areas, 1,496,105 tons in forested areas, 831,705 tons in grasslands, 1,021,742 tons in wetlands, and 206,709 tons in bare areas, the water bodies was estimated to be 38,087 tons. In the case of more severe 100-year rainfall, 1,808,376 tons in urbanized/dried areas, 1,172,505 tons in agricultural areas, 2,076,019 tons in forests, 1,021,742 tons in grasslands, 47,603 tons in wetlands, 238,363 tons in bare lands, and 52,985 tons in water bodies. The potential economic damage from flood runoff(100 years frequency) is 122,512,524 thousand won in residential areas, 512,382,410 thousand won in commercial areas, 50,414,646 thousand won in industrial areas, 2,927,508 thousand won in Infrastructure(road), 8,907 thousand won in agriculture, Total of assuming a runoff of 50 mm(100 year frequency) was estimated at 688,245,997 thousand won. In a conclusion. these results provided an overview of ecosystem functions and services in terms of flood control, and indirectly demonstrated the possibility of using the model as a tool for policy decision-making. Nevertheless, in future research, related issues such as application of models according to various spatial scales, verification of difference in result values due to differences in spatial resolution, improvement of CN(Curved Number) suitable for the research site conditions based on actual data, and development of flood damage factors suitable for domestic condition for the calculation of economic loss.

• Korean Journal of Agricultural and Forest Meteorology
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• v.25 no.4
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• pp.376-386
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• 2023

Due to climate changes, landslide hazards in the Republic of Korea (hereafter South Korea) continuously increase. To establish the effective landslide mitigation strategies, such as erosion control works, landslide hazard estimation in the long-term perspective should be proceeded considering the influence of climate changes. In this study, we examined the change in landslide-damaged areas in South Korea responding to climate change scenarios using the multivariate regression method. Data on landslide-damaged areas and rainfall from 1981-2010 were used as a training dataset. Sev en indices were deriv ed from rainfall data as the model's input data, corresponding to rainfall indices provided from two SSP scenarios for South Korea: SSP1-2.6 and SSP5-8.5. Prior to the multivariate regression analysis, we conducted the VIF test and the dimension analysis of regression model using PCA. Based on the result of PCA, we developed a regression model for landslide damaged area estimation with two principal components, which cov ered about 93% of total v ariance. With climate change scenarios, we simulated landslide-damaged areas in 2030-2100 using the regression model. As a result, the landslide-damaged area will be enlarged more than the double of current annual mean landslide damaged area of 1981-2010; It infers that landslide mitigation strategies should be reinforced considering the future climate condition.

• Korean Journal of Social Welfare
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• v.63 no.3
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• pp.187-211
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• 2011

This study examines the effects of active labor market policy on unemployment by pooled cross-section time series analysis utilizing panel data of 18 OECD countries, and seeks implications for improvements of the Korean active labor market policy. The results of the analysis are summarized as follows. First, active labor market policy negatively affects unemployment rates. Second, vacational training program among three major active labor market programs has a negative effect on unemployment rates. Third, employment service program and employment subsidy program have partially negative effects on unemployment rates. The implications for the Korean active labor market policy are as follows. First, it is necessary to expand and systematize active labor market policies. Second, vocational training programs should be systematized and professionalized according to labor demand. Third, employment subsidy programs need to be planned and carried out under the condition of minimizing a substitution effect, a displacement effect and a deadweight loss effect. Fourth, employment service programs need to be developed and carried out under the consideration of not only the reduction of unemployment rates but also the prevention of re-unemployment, mitigation of income inequality and improvement of productivity.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.5 no.1
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• pp.33-43
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• 2007

This study divided 35 hemiplegia patients into control group having standard physical therapy and gait training and functional electrical stimulation(FES) group using FES during gait training in order to examine the effects of applying FES to ankle joint dorsiflexor on motor unit action potential. Stimulation conditions of FES were pulse rate 35 pps, pulse width $250{\mu}s$, and on-time 0.3 second, treatment hour was 30 min. and treatment period was once a day for five days a week through six weeks. For functional evaluations before and after treatment, root mean square(RMS) were measured and the following conclusions were obtained. : In RMS analysis of motor unit action potential, gastrocnemius was significantly reduced in both weight bearing(p<.001) and bearing condition (p<.05). In conclusion, application of FES to hemiplegia patients in recovery stage during gait training decreased RMS and it was interpreted that it was caused by mitigation of muscular spasticity by reduction of motor unit.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.2
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• pp.158-164
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• 2014

LEO(Low Earth Orbit) Satellite which is discarded should be reentered to atmosphere in 25 years by '25 years rule' of IADC(Inter-Agency Space Debris Coordination Committee) Guidelines. If the parts of satellite are survived from severe aerothermodynamic condition, it could damage to human and property. South Korea operates KOMPSAT-2 and STSAT series as LEO satellite. It is necessary to dispose of them by reentering atmosphere. Therefore this paper analyze the trajectory, survivability, casualty area and casualty probability of a virtual LEO satellite using ESA(European Space Agency)'s DRAMA(Debris Risk Assesment and Mitigation Analysis) tool. As a result, it is noted that casuality area is $15.2742m^2$ and casualty probability is 5.9614E-03 then will be survived 198.831kg.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.1
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• pp.40-47
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• 2011

Mobile harbor which is a novel concept of ocean transportation to bring the containers from the cargo ship waiting on the ocean away is being focused now. To provide the mobile harbor with the stable loading/unloading condition, it is necessary to develop the oscillation mitigation technologies such as anti-rolling system. Anti-rolling system using AMD(Active Mass Driving) has merits that it can handle the disturbances more actively and mitigate the rolling oscillation faster than other type anti-rolling system. However, rack-and-pinion type AMD has problems such as big friction noise from gears and motor, wear and tear, and continuous maintenance. In this paper, novel anti-rolling system using Maglev type AMD for mobile harbor is suggested in order to resolve the problems caused by the friction. This novel anti-rolling system doesn't make any friction because it supports the moving mass by using magnetic levitation force and moves it by using propulsion force from the linear motor. The demo system of the novel anti-rolling system using maglev type AMD has been developed in order to investigate its feasibility. This paper presents the procedures and results of development of this demo system.