• Journal of Korean Society on Water Environment
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• v.27 no.6
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• pp.848-854
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• 2011

The objective of this research was to experimentally test the effect of rice straw mats on the reduction of runoff, sediment and discharge under a laboratory scale with different rainfall intensity and slopes. We used the small runoff plots of $1m{\times}1m{\times}0.65m$ ($L{\times}W{\times}H$) in size were filled with loamy sand. Experimental treatments were bare (control), rice straw mats + PAM(SP), rice straw mats + PAM + sawdust(SPS) and rice straw mats + PAM + rice husks(SPR); slope of 10% or 20%; and rainfall intensity of 30 or 60 mm/hr. Runoff volume and coefficient from covered plots were significantly lower than those from control plots. Under the 30 mm/hr and 10% simulations, average runoff coefficient of covered plots decreased more than 92%. Under 60 mm/hr and 20% simulations, the ratios were between 39.8~58.1%. Under the condition of 30 mm/hr rainfall and 10% slope, sediment discharge from covered plots was practically zero. And at 20% plots, sediment reduction ratio was more than 95%. Under the condition of 60 mm/hr rainfall, sediment reduction ratio of 10 and 20% plots ranged between 86.3~95.3% and between 79.8~86.5%, respectively. The differences in initial runoff time, runoff and sediment discharge among different cover materials were not significant. Rainfall intensity showed higher impact on initial runoff time, runoff, and sediment discharge than slope. It was also shown that even if runoff reduction by surface cover were low, sediment discharge reduction could be very significant and contribute to improve the water quality of streams in sloping agricultural regions. It was concluded that the use of straw mat and PAM on sloping agricultural fields could reduce soil erosion and muddy runoff significantly and help improve the water quality and aquatic ecosystem in receiving waters.

• Journal of Korean Society on Water Environment
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• v.27 no.2
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• pp.200-209
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• 2011

The purpose of the study is to optimally manage sewage treatment plant with analysis of phosphorus contribution and improvement of water quality contributing rate in the effect of inflowing point of effluent and Pal-Dang lake after reducing T-P discharge from large scale public sewage treatment plant at upstream of Pal-Dang lake. Also, this study, for enforcement of T-P in effluent, plans optimal management of effluent T-P through examining propriety of environmental, technological, and economical aspect such as water quality standard of domestic and foreign T-P and related policy. In regarding optimal management of T-P discharged from public sewage treatment plant located in upstream of Pal-Dang lake, the study drew following conclusions. With the optimal management of public sewage treatment plant, it showed that a pollution level became higher in the order of Sumgang E in South-Han river, C in Dalcheon, B1 B2, A in North-Han river, and J in Kyungancheon, and it is required reduction of T-P first. The highest value in analysis of benefit-costs from sewage treatment plant in the selected research area was Kyungan B, and the others are with the order of Jojong A, Bokha A, Kyungan A, and Yanghwa A. With result of this study, all 14 areas are required more enforced phosphorus treatment. The study resulted that the most top priority areas were Hangang F, Sumgang B, and Gyungan A, top priority areas were Bokha A, Dalcheon B, and Cheongmi A, priority areas were Hangang E, Heukcheon A, Gyungan B, and Jojong A, and potential areas were Sumgang A, Yanghwa A, Dalcheon A, and Hangang D. It seems to be appropriate to apply 0.2 mg/L of T-P treatment for water supply source reservation, 0.5 mg/L for the other areas by locally, and 0.2~0.5 mg/L for biological nitrogen phosphorus treatment method and 0.5~1 mg/L for Conventional Activated Sludge by technologically. Also, it may be appropriate to apply 0.2 mg/L for the most top priority area(I), 0.3 mg/L for the top priority area(II), 0.4 mg/L for priority area(III), and 0.5 mg/L for potential area(IV) by the separation of priority area.

• Journal of The Geomorphological Association of Korea
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• v.19 no.3
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• pp.143-151
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• 2012

The tsunami disasters and tectonic movements derived from mega-earthquake(M 9.0) which occured in the sea floor of the Pacific side of northeast Japan in March, 2011 were investigated. Landward invasion limit of the tsunami was 4.0km from the present coastline in Sendai coastal plain. It was observed that sandy deposit was dristributed largely in coastward part and muddy deposit was distributed largely in landward part. The ratios of distribution distances of the above two deposits were, respectively, 60~75% and 25~40% of the whole invasion distance of the 2011 tsunami. The ratios of the above distribution distances of tsunami deposits could be used to estimate landward invasion distances of the past maga-tsunamies(e.g. '2,000year B.P. Mega-Tsunami' and 'Jogan Tsunami' etc.) in Sendai coastal plain. The mega-scale tsunami disasters were caused by the low and flat geomorphic condition in the Sendai coastal plain and the increasing effect of tsunami height affected by narrow inlet condition of the so-called Ria's coast in the Sanriku coastal area respectively. Tectonic subsidences caused by the mega-earthquake in march, 2011 were observed in many areas of Ishinomaki, Ogawa, Ogachi and Onagawa coasts in northeast Japan. The displacements of tectonic subsidence were between 0.5 meters and 1.0 meters.

• Journal of Coastal Disaster Prevention
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• v.5 no.4
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• pp.173-182
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• 2018

As the research about increasing the efficiency of dredging soil transport, the technology, which reduce the friction between pipe wall and fluid in the pipe and disturbed generating pipe blockage, has been developed. So for the purpose of applying this technology to real construction site, main test has been tried at the real scale test in field. As a test result, this paper will show 30% flow efficiency increasing by permitted electro magnetic force to the pipe. And test result was evaluated as a ultra sonic velocity profiler. To propose the design technique and the execution manual of the high efficiency dredging material transport technic, this research have confirmed flow status changing depending on a soil material kind under electro-magnetic field and analyze the effect of electro-magnetic field which affects to each dredged soil material transportation. For achieving this research, EMF(Electro-Magnetic Field) generator is installed on the dredger(20,000HP) and through monitored flow status, dredging soil flow rate and sampled material specification is confirmed. Also dredger operating condition is measured and dredger power for soil transportation, hydraulic gradient and flow rate are compared, as transportation efficiency is calculated by this parameter, it is possible to check transportation efficiency improvement depending on each dredged soil material under electro-magnetic field. To verify the technique of dredged soil transfer using electromagnetic field, which is the core technique of the high efficiency dredged soil transfer, and the technique of expert system for pipeline transfer and the flow state. This could lead to a verification of transfer efficiency according to the characteristics of the dredged soil (sand, clay, silt) and the transfer distance (5km, 10km, 15km), which is planned to be used for a technology development of pump power reduction and long-distance transfer applying the high efficiency dredged soil transfer technology.

• Korean Journal of Labor Studies
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• v.17 no.1
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• pp.177-208
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• 2011

This article examines that how in-house subcontract has been introduced and developed in metal industry in 1970s, focusing typical workplaces in steel industry. That was essential for the capital to insure control mechanism for large number of laborer because of mobilizing a large scale of capital in industrialization of heavy metal industry. In case of Pohang steel industry, this necessity was fulfilled by introduction and imitation of Japanese personnel management by being included of Japanese economic hinterland. This was embodied in both constructing internal labor market for regular workers and introducing in-house subcontracting system for contingent workers at workplaces. This was exceptional comparing in-house subcontracting system in Korean steel industry with in-house subcontracting system in advanced economies, because of disappearing in-house subcontracting system by making internal labor market. And this was closely linked by late development of Korea. Implications of Pohang steel company's case are as follows : first, late development effect in formation of employment system, second, in linking informality of Korean employment system. This implications mean that in-house subcontracting in steel industry is structured as mechanism for personnel management in large factory being influenced by industrialization of heavy industry. In this point, improvements which include wide economic solution beyond labor solution for present problem of in-house subcontracting system is desirable.

• Journal of Family Relations
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• v.21 no.1
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• pp.143-160
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• 2016

Objectives: The purpose of this study is to empirically verify the difference between traditional gender role attitude and realistic dual earner attitude. Most preceding studies analyzed gender role attitude by summated rating scale while few studies have been conducted on the difference between traditional gender role attitude and dual earner attitude. Method: By using the 9th Korea Welfare Panel Data (year 2014), this study extracted households of married couples and with children in working age (18 through 64 years of age) who are the main subjects in work-family relationship. First, this study classified traditional group and modern group in their gender role attitude and passive group and active group in their dual earner attitude and by crossing these attitudes, drew out 4 gender role/dual earner attitudes. For analysis, this study investigated frequency of attitude types through descriptive statistics. By conducting ANOVA, study verified if there are significant differences in the satisfaction with family relationship depending on the types of gender role/dual earner attitudes. Lastly, study examined the effect of socio-economic status and demographic characteristics on the types of gender role/dual earner attitudes by conducting multi-nominal logistic regression analysis. Results: As the result of analysis, first, half of respondents belonged to 'equal-role-oriented type' who has modern gender role attitude and active dual earner attitude. However, there were not a few 'dual-earner-avoiding type' who has modern gender role attitude but passive dual earner attitude and 'incongruous attitude type' who has traditional gender role attitude but active dual earner attitude. Next, 'incongruous attitude type' had significantly low level of satisfaction with overall family life, relationship with spouse and relationship with children than other attitude types. Lastly, those whose incomes belong to poor strata, those who are high school graduates and lower, males and those who are over the age of 60 had significantly higher probability of belonging to 'incongruous attitude type.' Conclusion: The results of analysis demonstrate that the difference between gender role attitude and dual earner attitude is an important matter and since 'incongruous attitude type' exhibits low level of satisfaction with family relationship, scrupulous policy approaches are required for those who have high possibility of belonging to 'incongruous attitude type.'

• The Journal of the Korea Contents Association
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• v.21 no.3
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• pp.490-504
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• 2021

The online market is gradually increasing due to the increase in single-person households, the development of information and communication technologies, the emergence of various new products, and price comparison competition. Companies need differentiation strategies to adapt to changes in the online environment and secure a competitive edge. In this environment, the objective is to consider the importance of consumer perception of websites in order to generate continuous growth and revenue in the online market as well as to differentiate them from competitors using an online service environment that can affect consumers' internal responses. In this study, we present aesthetic, functional, privacy, and interaction factors as components of e-servicescape to study the impact of e-servicescape on website trust, brand attitude, and repurchase intention. In the data analysis, 485 ordinary people with online shopping experience were surveyed. The questionnaire was based on a 7-point Likert scale for each question and statistical analysis was conducted using SPSS 24.0 and AMOS 25.0. The analysis shows that in e-servicescapes aesthetic and privacy factors influence website trust and brand attitudes and consequently affect repurchase intention.

• Journal of the Korean earth science society
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• v.42 no.1
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• pp.76-87
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• 2021

In this study, temporal trend of researches in earthquake with groundwater level, water quality, radon, remote sensing, electrical resistivity, gravity, and geomagnetism was searched from 2001 to 2020, using the journals indexed in Web of Science, and the number of articles published in international journals was counted in relation to the occurrences of earthquakes (≥Mw 5.0, ≥Mw 6.0, ≥Mw 7.0, ≥Mw 8.0, and ≥Mw 9.0). The number of articles shows an increasing trend over the studied period. This is explained by that studies on earthquake precursor and seismic monitoring becomes active in various fields with integrated data analysis through the development of remote sensing technology, progress of measurement equipment, and big data. According to Mann-Kendall and Sen's tests, gravity-related articles exhibit an increasing trend of 1.30 articles/yr, radon-related articles (0.60 articles/yr), groundwater-related articles (0.70 articles/yr), electrical resistivity-related articles (0.25 articles/yr), and remote-sensing-related articles (0.67 articles/yr). By cross-correlation analysis of the number of articles in each field with removing trend effect and the number of earthquakes of ≥Mw 5.0, ≥Mw 6.0, ≥Mw 7.0, ≥Mw 8.0, and ≥Mw 9.0, radon and remote sensing fields exhibit a high cross-correlation with a delay time of one year. In addition, large-scale earthquakes such as the 2004 and 2005 Sumatra earthquake, the 2008 Sichuan earthquake, the 2010 Haiti earthquake, and the 2010 Chile earthquake are estimated to be related with the increase in the number of articles in the corresponding periods.

• The Journal of Pediatrics of Korean Medicine
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• v.35 no.1
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• pp.139-147
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• 2021

Objectives The purpose of this study is to investigate differences in brain activities when Neurodevelopmental treatment (NDT) is used alone compare to NDT is combined with intradermal acupuncture (IDA) treatment, using functional infrared spectroscopy (fNIRS) Methods Three children less than 7 year-old with cerebral palsy were participated. On their first visit, only NDT was used. After a week, they were treated with both NDT and IDA. During the treatment, fNIRS was used to measure any changes in their brain activities. Results In first patient with NDT, oxyhemoglobin level was increased during Standing exercise and Gait training compared to resting state. When the patient was treated with NDT and IDA, oxyhemoglobin level was decreased during Standing exercise and Gait training compared to resting state, and the result was significant (p<0.05). In second patient, oxyhemoglobin level was decreased in Gait training compared to resting state when NDT was used, but the level was increased when NDT and IDA were used in Gait training compared to resting state (p<0.05). In third patient, the difference in oxyhemoglobin levels between Gait training and resting state was significant (p<0.05). Conclusions Treatment involving both NDT and IDA has more potential to improve brain activities compared to that of NDT alone, and no adverse effect was reported. In order to confirm the finding, larger scale randomized controlled trials are needed.

• Journal of Korean Medicine for Obesity Research
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• v.21 no.1
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• pp.22-31
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• 2021

Objectives: We conducted a retrospective chart review to investigate the effects of Korean Medicine (KM) treatment on weight loss in patients with morbid obesity (body mass index [BMI]≥30 kg/m²) and to compare the effects of KM counseling and non-counseling on weight loss. Methods: We performed a retrospective chart review of patients with morbid obesity who received KM treatment for at least 1 month. We evaluated the effects of KM treatment on body weight, BMI, body fat, fat mass, EuroQol-5D, and the Korean version of the obesity-related quality of life scale (KOQOL). We also assessed the liver and kidney functions, and adverse events. We performed a comparative analysis between the counseling and non-counseling groups. Results: A total of 37 patients who underwent 4 weeks of KM treatment involving Wolbi-tang, electroacupuncture, and KM counseling were included in this study. Twenty-one patients were assigned to the counseling group and sixteen patients to the non-counseling group. There was a significant decrease in weight, BMI, fat mass, and KOQOL (P<0.05) with improvements in total cholesterol, low-density lipoprotein, and triglycerides. The counseling group had a greater reduction in body weight, BMI, body fat, and fat mass compared to the non-counseling group, although it was not significant. In the BMI below 35 (n=25), the reduction ratio of body weight, body fat mass, and body fat was higher in the counseling group than in the non-counseling group; additionally, body fat decreased significantly in counseling group (P<0.05). No severe adverse effects were observed. Conclusion: KM treatment could be effective for weight loss, especially in patients with morbid obesity, KM counseling could also be a good tool for weight loss, typically in patients with BMI<35 kg/m².