• Journal of Radiation Protection and Research
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• v.36 no.4
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• pp.209-215
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• 2011

In order to investigate the soil-to-plant transfer factor (TF) of $^{99}Tc$ for Korean major upland crops (soybean, radish and Chinese cabbage), pot experiments were performed in a greenhouse. Soils were collected from four upland fields (two for soybean and two for radish and Chinese cabbage) around Gyeongju radioactive-waste disposal site. Three to four weeks before sowing, dried soils were mixed with a $^{99}Tc$ solution and the mixtures were put into pots and irrigated. TF values were expressed as the ratios of the $^{99}Tc$ concentrations in plants (Bq $kg^{-1}$-dry or fresh) to those in soils (Bq $kg^{-1}$-dry). There was no great difference in the TF value between soils. The TF values for soybean seeds were extremely lower than those for the straws, indicating a very low mobility of $^{99}Tc$ to seeds. As representative TF values of $^{99}Tc$, $1.8{\times}10^{-1}$, $1.2{\times}10^1$, $3.2{\times}10^2$ and $1.3{\times}10^2$ (for dry plants), arithmetic means for two soils, were proposed for soybean seeds, radish roots, radish leaves and Chinese cabbage leaves, respectively. In the case of the vegetables, proposals for fresh plants were also made. The proposed values are not sufficiently representative so successive updates are needed.

• Journal of The Korean Astronomical Society
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• v.49 no.5
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• pp.199-208
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• 2016

We present photometric results of the δ Sct star V1162 Ori, which is extensively monitored for a total of 49 nights from mid-December 2014 to early-March 2015. The observations are made with three KMTNet (Korea Microlensing Telescope Network) 1.6 m telescopes installed in Chile, South Africa, and Australia. Multiple frequency analysis is applied to the data and resulted in clear detection of seven frequencies without an alias problem: five known frequencies and two new ones with small amplitudes of 1.2-1.7 mmag. The amplitudes of all but one frequency are significantly different from previous results, confirming the existence of long-term amplitude changes. We examine the variations in pulsation timings of V1162 Ori for about 30 years by using the times of maximum light obtained from our data and collected from the literatures. The O − C (Observed minus Calculated) timing diagram shows a combination of a downward parabolic variation with a period decreasing rate of (1/P)dP/dt = −4.22 × 10⁻⁶ year⁻¹ and a cyclic change with a period of about 2780 days. The most probable explanation for this cyclic variation is the light-travel-time effect caused by an unknown binary companion, which has a minimum mass of 0.69 M_⊙. V1162 Ori is the first δ Sct-type pulsating star of which the observed fast period decrease can be interpreted as an evolutionary effect of a pre-main sequence star, considering its membership of the Orion OB 1c association.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.2
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• pp.123-129
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• 2011

A study on the occurrence and movement of marine debris is required for protecting the marine environment and ecosystem from marine pollution. The aim of this study is to show annual production and movement characteristics through analysis for the flow path, composition and the sources of marine debris. This study analyzed the distribution and characteristics of marine debris collected in the region of $100\;m{\times}20\;m$($=2,000\;m^2$) at the Daekwang Beach in the Yellow Sea. During the collection period from 2008 to 2010, the total weight of the marine debris was 1,445 kg in this site. The most marine debris was plastic amounting to 46.5% of the whole collection; the rest were styrofoam(20%) and wooden material(12.6%). The amount of marine debris mused from foreign country observed 155.5 kg, more than 90% of them was plastic came from China such as buoys. Additionally, this study analyzed seasonal change if marine environment to understand occurrence amount change if marine debris. 2009 and 2010 was high occurrence ratio in season that the north wind is very strong and the occurrence rate appeared highest by 40% in the summer(July) of 2008 that appeared westbound tidal current. Overall, marine Debris mused from foreign country was high occurrence ratio in January, May and then November has a lot of quantity secondly. While, occurrence ratio was the highest by 46% summer(July) in 2008, but in 2009 and 2010 showed the lowest rate to 4%.

• Journal of Digital Convergence
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• v.14 no.11
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• pp.379-388
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• 2016

This study was aimed at identifying the actual state of workplace violence based on a survey conducted to 876 subway workers in Seoul and determining the relationship between workplace violence and mental health of workers. Data were collected via web site, using a structured questionnaire and for the analysis of the data, a multiple linear regression analysis was carried out by the statistical program SPSS 20.0. According to the results, the perpetrators of violence turned out to be "passengers" in all types of workplace violence: physical violence, verbal violence, sexual harassment and disregard for personality. As for the relationship between workplace violence and the mental health of the workers, statistically significant differences were shown between all the above mentioned workplace violence types and sub-areas of mental health. Also, as for the impact of workplace violence on the mental health of the workers, significant differences were found in physical violence, sexual harassment and disregard for personality, with 8.3 percent of explanatory power. Based on these findings, the study suggests the establishment and the application of customer interaction guidelines to protect subway workers from workplace violence along with specific measures customized for each work environment to prevent violence.

• Informatization Policy
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• v.24 no.4
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• pp.3-16
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• 2017

With the development of social media services in the era of Web 2.0, the public opinion formation site has been partially shifted from the traditional mass media to social media. This phenomenon is continuing to expand, and public opinions on government polices created and shared on social media are attracting more attention. It is particularly important to grasp public opinions in policy formulation because setting up educational policies involves a variety of stakeholders and conflicts. The purpose of this study is to explore public opinions about education-related policies through an empirical analysis of social media documents on education policies using opinion mining techniques. For this purpose, we collected the education policy-related documents by keyword, which were produced by users through the social media service, tokenized and extracted sentimental qualities of the documents, and scored the qualities using sentiment dictionaries to find out public preferences for specific education policies. As a result, a lot of negative public opinions were found regarding the smart education policies that use the keywords of digital textbooks and e-learning; while the software education policies using coding education and computer thinking as the keywords had more positive opinions. In addition, the general policies having the keywords of free school terms and creative personality education showed more negative public opinions. As much as 20% of the documents were unable to extract sentiments from, signifying that there are still a certain share of blog posts or tweets that do not reflect the writers' opinions.

• The Korean Journal of Pesticide Science
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• v.15 no.4
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• pp.441-452
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• 2011

This study was carried out to survey the residual characteristics of endocrine disruptor (ED)-suspected pesticides in greenhouse soils and assess their leachabilites to groundwater. Greenhouse soils were collected from 40 sites of greenhouse in 2008 in Korea. Sixteen ED-suspected pesticides which had been using in Korea, such as alachlor, benomyl, carbaryl, cypermethrin, 2,4-D, dicofol, endosulfan, fenvalerate, malathion, mancozeb, metribuzin, metiram, methomyl, parathion, trifluralin, and vinclozolin, in the soils, were analyzed by chromatographic methods using GLC-ECD and HPLC-DAD/FLD. Limits of detection (LODs) of the test pesticides ranged from 0.0004 to 0.005 mg/kg. Recoveries of the target pesticides from soil ranged from 72.69 to 115.28%. Four pesticides including cypermethrin were detected in the range of from 0.001 to 2.019 mg/kg, representing that their detection rate from greenhouse soils was 37.5%. The highest detection rate was observed from endosulfan which was detected from 16 site soils of the total samples, indicating that endosulfan is persistent in soil because of its very low mobility and high adsorption characteristics in soil. Based on the groundwater ubiquity scores (GUSs) of the pesticides detected from greenhouse soils, most of them have little possibilities of groundwater contamination except the fungicide vinclozolin with some leaching potential because of high water solubility and very low soil adsorption property.

• International Journal of Contents
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• v.11 no.2
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• pp.37-49
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• 2015

Sensors, equipment, ICT facilities and their corresponding software have a relatively short lifetime relative to that of constructional structure, so these devices have to be continuously fixed or exchanged during maintenance and management. Furthermore, software or analysis tools should be periodically upgraded according to advances in ICT and analysis technology. Conventional monitoring systems have serious problems in that it is difficult for site engineers to modify or upgrade hardware and analysis algorithms. Moreover, we depend on the original system developer when we want to modify or upgrade inner program structures. In this paper, we propose a novel design for integrated maintenance and management of a monitoring system by applying the mobile cloud concept. The system is intended for use in disaster prevention of constructional structures, including bridges, tunnels, and in traditional buildings in a local heritage village, we analyze the status of these structures over a long term or a short-term period as well as in disaster situations. Data are collected over a mobile cloud and future expectations are analyzed according to probabilistic and statistical techniques. We implement our integrated monitoring system to solve the existing problems mentioned above. The final goal of this study is to design and implement a monitoring system for more than 10,000 structures spread within Korea. Furthermore, we can specifically apply the monitoring system presented here to a bridge made from timber in Asan Oeam Village and a traditional house in Andong Hahoe Village to monitor for possible disasters. The entire system design and implementation can be developed on the LinkSaaS platform and the monitoring services can also be implemented on the platform. We prove that the proposed system has good performance by performing a TTA authentication test, web accommodation test, and operation test using emulated data.

• Journal of Korean Society of Forest Science
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• v.86 no.1
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• pp.46-55
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• 1997

This study tried to categorize the types of mountain-village areas in terms of some key variables representing the socio-economic and natural characteristics in order to provide basic information for policy formation of mountain areas. Cross-sectional data of the year 1990 for 900 sub-counties were collected to analyse the characteristics of mountain-village areas. Eleven variables were selected to classify the types of sub-county levels. According to the results of the study, the socio-economic conditions of mountain-village areas represented by the number of corporations, number of non-farming households, and population density of mountain-village areas were found to be inferior to other parts of the nation while the proportion of forest land, share of non-paddy crop fields, distance from cities, percentage of farming households, and elevation from the sea-level were higher to the other areas. By the principal factor analysis, the key variables representing industrial development, mountain-ousness, and accessibility from near cities were selected. By a cluster analysis employing the selected variables, 5 different types of mountain-village areas were categorized.

• Korean Journal of Childcare and Education
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• v.9 no.5
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• pp.407-436
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• 2013

This study, based on understanding the play features of the participants, explores early children's peer-relation strategies of maintaining and altering play frame and understanding the meaning of the strategies. Free play of 5-year-old children's was observed. The child-care center was visited 1 or 2 days a week, from March to October, 2012. The data collected were based from field notes, interviews with participants, their workbooks and more. The participants used strategies such as 'refusing', 'incapacitating', 'interpreting in a way to sympathize', and 'changing the rules of play' to maintain the play, whilst 'tell-on', 'being on the same side', 'accepting 3rd party' features were used to alter play frame. Participants using these various play-frame strategies experienced life implications of 'dialectic of exclusion and selection' and 'quiver of boundary'. This study, specifying efforts of the children to maintain and alter the play frame, will provide an understanding of perception of "social exclusion" to children, which has been viewed negatively in the past. It will also benefit on-site teachers in helping them understand peer-relationship within children and provide a more in-depth intervention for peer-relationship issues.

• Bulletin of the Korean Chemical Society
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• v.33 no.11
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• pp.3651-3656
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• 2012

The size-segregated atmospheric aerosols have been collected at 1100 m site of Mt. Halla in Jeju, a background area in Korea, using 8-stage cascade impact air sampler during Asian dust and non-Asian dust storm periods. Their ionic and elemental species were analyzed, in order to examine the pollution characteristics and composition change between Asian dust and non-Asian dust periods. The major ionic species such as nss-$SO_4{^{2-}}$, $NH_4{^+}$, and $K^+$ were predominantly distributed in the fine particles (below $2.1{\mu}m$ diameter), and besides the $NO_3{^-}$ was distributed more in coarse particle fraction than fine particle. On the other hand, the typical soil and marine species i.e., nss-$Ca^{2+}$, $Na^+$, $Cl^-$, and $Mg^{2+}$, were mostly existed in the coarse particles (over $2.1{\mu}m$ diameter). As well in the elemental analysis of aerosols, the major soil-originated Al, Fe, Ca, and others showed prominently high concentrations in the coarse particle fraction, whereas the anthropogenic S and Pb were relatively high in the fine particle fraction. From the comparison of aerosol compositions between Asian dust and non-Asian dust periods, the concentrations of the soil-originated species such as nss-$Ca^{2+}$, Al, Ca, Fe, Ti, Mn, Ba, Sr have increased as 2.7-4.2 times during the Asian dust periods. Meanwhile the concentrations of nss-$SO_4{^{2-}}$ and $NO_3{^-}$ have increased as 1.4 and 2.0 times, and on the contrary $NH_4{^+}$ concentrations have a little bit decreased during the Asian dust periods. Especially the concentrations of both soil-originated ionic and elemental species increased noticeably in the coarse particle mode during the dust storm periods.