• Journal of Labour Economics
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• v.38 no.3
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• pp.1-22
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• 2015

We analyze the effect of the minimum wage on employment using time series data forr groups of individuals most affected by the minimum wage: young males (18 to 24 years old), young females (18 to 22 years old), old males (60 years and older) and old females (60 years and older). Our findings are as follows. First, a unit root test says that the variables like minimum wages and employments are non-stationary variables and they have cointegrational relations each other. It says that in this case, VEC is more suitable than OLS or VAR. Second, an increase of the minimum wage is found to have a weak but persistently negative effect on employment.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.6
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• pp.426-433
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• 2013

This study was aimed to classify soil desalination area for cultivation using NDVI (Normalized difference vegetation index) of high-resolution satellite image because the soil salinity affects the change of plant community in reclaimed lands. We measured the soil salinity and NDVI at 28 sites in the Saemangeum reclaimed land in June 2013. In halophyte and non-vegetation sites, no relation was found between NDVI and soil salinity. In glycophyte sites, however, we found that the soil salinity was below 0.1% and NDVI ranged from 0.11 to 0.57 which was greater than the other sites. So, we could distinguish the glycophyte sites from the halophyte sites and non-vegetation, and classify the area that soil salinty was below 0.1%. This technique could save the time and labor to measure the soil salinity in large area for agricultural utilization.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.4
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• pp.297-302
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• 2015

Replacing a manual switch installed in a feeder for a distribution system with an automatic one increases the reliability of the electric power system. This is because the automatic switch can shorten the duration of a fault the customer experiences by splitting the faulty section faster than the manual one does. However, improving the reliability of the distribution system may increase investment costs. Here, the investment costs include automatic switch cost, replacement work cost and labor cost. For this reason, importance should be attached to the proper balance between the increase of the investment costs and the improvement of the reliability of the distribution system. This article analyzed reliability index and economics when manual switches installed in a feeder (RBTS Bus2 model) was replaced by automatic ones. In addition, it attempted to draw the optimum rate of automation of manual switches by automatic ones using the GRG optimization method, considering the current economic requirements.

• Neonatal Medicine
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• v.16 no.1
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• pp.94-98
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• 2009

Listeria monocytogenes (L. monocytogenes) is a foodborne anaerobic gram-positive rod and the third most common pathogen for neonatal meningitis. Although the mortality and morbidity of L. monocytogenes infections are high, thus causing serious problems in Western populations, neonatal listeriosis is relatively rare in Eastern countries, including Korea. Possible routes for intrauterine infection or vertical transmission of L. monocytogenes include infected placentas and the reproductive tract. Intrauterine infections may cause chorioamnionitis, preterm labor, spontaneous abortion, stillbirth, or neonatal infection. A high index of suspicion and early empirical antibiotic treatment are critical to achieve a favorable prognosis for neonatal listeriosis. We managed a case of L. monocytogenes sepsis and pneumonia in a premature neonate born at 26 weeks of gestational age from an asymptomatic mother with culture-proven placental infection. The neonate was successively treated with ampicillin and gentamicin.

• Journal of Labour Economics
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• v.39 no.1
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• pp.1-31
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• 2016

This paper investigates the cyclical behavior of UI benefit take-up rate, the share of unemployed persons who are eligible for job seekers' allowances(JSA) and actually receive them. Using Korea's Employment Insurance DB, it also identifies the factors linked to the decision to take up job seekers' allowances. The results show that the take-up rate is countercyclical and leads both unemployment rate and Coincident Composite Index cyclical component by 6 months and is positively correlated with replacement rate and benefit duration, suggesting that extending benefit duration and raising benefit level can boost benefit claims to increase take-up rates in Korea.

• Journal of Korean Society of Rural Planning
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• v.23 no.2
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• pp.9-17
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• 2017

Rural development policy has changed from hardware based development to community revitalization. The purpose of this study is to analyze social network of collaborative activity among rural organizations as fundamental of community. The material used in this study is a record of collaborative activites in the community newsletter of Hong-Dong area. 161 of collaborative activities (links) and 75 of organizations (nodes) are investigated in network. 6 collaborative activity type ('Education', 'Socializing', 'Meeting', 'Culture', 'Event' and 'Labor') is classified. 'Socializing' is inclusive of approximately half of whole network (50.67%). Closeness centraization, degree centralization and betweenness centralization are measured on top in 'Education', 'Meeting' and 'Event' type. Scatter plot analysis using degree and betweenness centrality index, 'Maeul Revitalization Center', 'Balmak Library', 'Woori-Maeul Medical Co-op', 'Support Center for Female Farmers', 'Hongdong Middle School' and 'Mundang Sustainable Agriculture Education Center' are resulted as the core organization in network. Geographical distribution of collaborative activity is not only concentated in Hong-Dong Myeon but also networked with adjacent administrative district. This study finds its purpose in the detailed analysis of network characteristics of collaborative activity within Hong-Dong area which is representative developed rural community in Korea.

• Proceedings of the KSRS Conference
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• v.1
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• pp.94-97
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• 2006

Timber stand age information of timber in industrialized plantation forest is generally collected by field surveying which is labor-intensive, time-consuming, and very costly. It is also inconsistent in analyses perspective. As an alternative, The objective of this research is to present a practical solution for estimating timber age of loblolly pine plantation using Landsat thematic mapper (TM) images, shuttle radar topography mission (SRTM), and national elevation dataset (NED). A multivariate regression model was developed based upon satellite image-based information (i.e.normalized difference vegetation index (NDVI), tasseled cap (TC) transformation, and derived tree heights). A residual studentized technique was applied to remove potential outliers. After that, a refined age estimation model with a correlation coefficient R-square of 84.6% was obtained. Finally, the feasibility test of estimated model was performed by comparing estimated and measured stand ages of timber plantations using test datasets of plantation stands (2,032 stands). The result shows that the proposed method of this study can estimate loblolly pine stand age within an error of $2{\sim}3$ years in an effective and consistent way in terms of time and cost.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.05a
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• pp.57-60
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• 2008

This study investigated the results of insulation heat curing method using double layer bubble sheet in slab concrete and mass concrete in cold weather environment. First of all, when double bubble sheets are applied, it was shown that slab concrete was protected from early freezing by remaining between 6 and 15℃ even in case outside temperature drops -9℃ below zero until the 2nd day from piling, and in the case of mass concrete, with the maximum temperature difference between the center and surface less than 4℃, crack occurrence index was close to 2 and no hydration heat crack occurred by internal constraint. The insulation heat preservation curing method using the double bubble sheet applied in this field prevented early freezing owing to stable curing temperature management, deterring concrete strength development delay at low temperature, and obtained the needed strength. Also, it was proven that the method is highly effective and economic for cold weather concrete quality maintenance through curing cost reduction like construction period shortening and labor cost reduction, etc by reducing the process of temporary equipment installation and disassembling.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.26 no.4
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• pp.426-435
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• 2016

Objectives: The major objective of this study was to analyze stress response after a change to consecutive day shifts from day and night shifts in a motor assembly factory. Methods: Using a survey conducted by a labor union, we collected data on stress response index(SRI), lifestyle factors, work-family conflict and job stress before and after a shift system change. We analyzed the transition on the SRI among 222 workers. The cut-off point for the SRI was a T-score over 60. Results: The high risk stress response group was 20.3% of the population before the shift system change. After the shift system change it decreased to 11.3%. After the shift system change, social support improved, leisure time became more sufficient, work-family conflict declined, and sleep quality in the night shift week improved. In multivariable linear regression, among workers under 40 years old sleep quality on night shift, leisure time sufficiency, social support and work-family conflict contributed to the improvement of stress response. Among workers over 40, work-family conflict contributed to the improvement of stress response. Conclusions: The change to consecutive day shifts improved stress response and mediated with improved nighttime sleep, decreased work-family conflict, increased leisure time and improved work-family conflict.

• Korean Journal of Clinical Laboratory Science
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• v.52 no.1
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• pp.36-44
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• 2020

With the advent of westernized diet and a lack of exercise, young female college students are paying more attention to their bodyweight and health. Whole-body vibration has been demonstrated to be a suitable training method for improving knee extension maximal strength in young female athletes, as well as the gait performance in elderly women. This study aimed to evaluate the effects of a vertical vibration intervention on the physical fitness and postural balance in young females. Fifty-four young women were recruited; all subjects were randomly assigned to the intervention group and control group. The intervention group underwent vertical vibration with a platform for 12 weeks. The results showed that body mass index and body fat percentage had decreased (P<0.05). In addition, their muscle endurance as indicated by a sit-up test and their flexibility as indicated by a sit-and-reach test were both increased. With regard to postural balance, their 30-second sit-to-stand and timed up and go test results were improved. At the same time, their mean single-leg stance with eyes closed time increased (P<0.05). However, there were no significant differences, meanwhile, for the control group. Overall, the results showed that the whole body vibration (WBV) intervention had some beneficial effects on physical fitness and postural balance in young women.