• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.567-572
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• 2016

Many studies have been performed since the introduction of GPS in Korea. As a result, positioning using GNSS was fully proposed. On the other hand, most of these studies focused on accuracy but analytical studies on the GNSS status and the national GNSS infrastructure of Korea are lacking. In this study, the status of multi-constellation GNSS and National Geographic Information Institute's CORS (Continuous Operating Reference Station) were identified for the benefit and direction of GNSS infrastructure enhancement. As a result, it has been operating Multi-constellation GNSS, such as GPS, GLONASS, Galileo, COMPASS, and QZSS for surveying. In addition, improvement was presented by the number of satellites, precision, PDOP, etc. through the experiment about VRS and RTK using Multi-constellation GNSS. Upgrading the infrastructure for satellite surveying was identified as a priority consideration. In the future, if a Multi-constellation GNSS service is possible in VRS service, the satisfaction of public administration service will improve, which will contribute greatly to the advancement of a surveying infrastructure.

• Economic and Environmental Geology
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• v.26 no.2
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• pp.167-174
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• 1993

Limited geochemical components have been detected in fluid inclusions from ore deposits in south Korea by non-destructive and destructive analytical methods. Review of fluid inclusion studies display that the homogenization temperatures and salinities are in direct proportion. W and Cu ore deposits tend to show higher homogenization temperatures and salinities than Au ore deposits. Abundant halite-bearing fluid inclusions from the Eonyang Granite producing precious amethyst crystals may indicate that the initial fluid originated from magma is highly saline as shown by the quartz from the granite. Raman Laser microprobe detected $CO_2$, $N_2$ and $CH_4$ in a gold deposit, while these components are hardly detected from other deposits, even though destrucive analysis has dectected $CO_2$, $N_2$, $CH_4$, $H_2S$, and $SO_2$ from most of ore deposits. Individual fluid inclusion shows quite different components. These results suggest that large numbers of fluid inclusions should be analysed by Raman Laser microprobe to gain reliable data. Halite-bearing inclusion is hardly found in fluid inclusions from epithermal gold deposits in south Korea. Geochemistry, homogeinzation temperature and salinity of fluid inclusions may be useful to apply for exploration to find a concealed orebody.

• Journal of Science Education
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• v.39 no.1
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• pp.113-131
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• 2015

The purpose of this study was to analyze the interactive patterns between teacher and students in middle school earthh science classroom, identify difference of discourse types between earthh science classes taught by majored and non-majored teacher, find the relationship between the discourse pattern and the type of teachers' questions. For that purpose, the participants in this study included four teachers and their students of three middle schools in Seoul. The data consisted of two parts. First, we categorized interaction between teacher and students into the types of discourses by the use of Mortimer and Scott's analytical framework(2003). Second, we classified teachers' questions into four different types of question based on MNeill & Pimentel's classification scheme(2009) to examine for the relationship between the discourse pattern and the type of teachers' questions. As a result, all teachers used interactive/authoritative discourse most in middle school earth science class. Therefore, there was more authoritative discourse to non-majored teacher in comparison with majored teacher. And study demonstrated that the discourse pattern was more related to feedback about student's response rather than the type of teachers' question. In other words, the dialogic discourse showed up more frequently when the teacher used delayed feedback with positive and accepting attitude.

• Journal of Food Hygiene and Safety
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• v.33 no.5
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• pp.354-360
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• 2018

This study presents a method validation for extraction and quantitative analysis of trichothecene mycotoxins in nuts based on quick, easy, cheap, effective, rugged, and safe (QuEChERS) approach for extraction and enhanced matrix removal (EMR)-lipid-disperive-SPE (d-SPE) cleanup method, with detection and quantification by high-performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) in positive- and negative-ion modes. Linearity, precision, and accuracy were validated for LC-MS/MS methods. Results obtained with LC-MS/MS were linear, with correlation coefficient ($R^2$) of 0.998. Limits of detection and quantification for mycotoxins were $0.41-3.57{\mu}g/kg$ and $1.23-10.82{\mu}g/kg$, respectively. Intra- and inter-day precisions (RSD, %) were 0.40-8.44% and 1.93-12.46%, respectively. Results indicated to be rapidly and accurately identifying trichothecene mycotoxins and may be used as a suitable safety management method for nuts and nuts related commodities.

• Journal of Food Hygiene and Safety
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• v.35 no.4
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• pp.312-318
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• 2020

A method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for neonicotinoid pesticide analysis in agricultural products. Four compounds (imidacloprid, clothianidin, acetamiprid, thiacloprid) were extracted with acetonitrile from agricultural products and cleaned up by NH₂ solid-phase extraction procedure, and eluted with 0.1% formic acid in methanol/dichloromethane (5/95, v/v). The limit of detection and quantification were 0.0001-0.0005 mg/kg and 0.001 mg/kg, respectively. The mean recoveries of neonicotinoid pesticide from agricultural products were in the range of 90.7-100.9% and 94.4-99.8%, as spiked at 0.2 mg/kg and 0.02 mg/kg, respectively. This validation satisfied the national criteria for pesticide analytical methods. In summary, The present method is fast, precise and sensitive enough for the Positive List System (PLS), and we conclude that the method is also suitable for neonicotinoid pesticide determination in a wide range of agricultural products.

• The Korean Journal of Food And Nutrition
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• v.27 no.3
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• pp.532-537
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• 2014

Cortex Phellodendri (CP) is derived from the dried bark of Phellodendron amurense. It has been widely used as a drug in traditional Korea medicine for treating diarrhea, jaundice, swelling pains in the knees and feet, urinary tract infections, and infections of the body surface. Many analytical methods have been used to study oriental herbal medicines, such as thin-layer chromatography, column liquid chromatography, and high performance liquid chromatography (HPLC). In this study, preparative centrifugal partition chromatography (CPC) was successfully carried out in order to separate pure compounds from a CP methanol extract. The optimum two-phase CPC solvent system was composed of n-butanol: acetic acid: water (4:1:5 v/v/v). The flow rate of the mobile phase was 3 mL/min in ascending mode with rotation at 1,000 rpm. The CPC-separated fraction and purification procedures were carried out by preparatory HPLC. The $^1H$ NMR spectrum revealed that the resonances at ${\delta}$ 4.10 and 4.20 ppm corresponded to three protons ($-OCH_3$), whereas those at ${\delta}$ 6.10 ppm corresponded to two protons ($-OCH_2O-$). Further, two aromatic protons (H-11 and H-12) conveys a doublet-doublet pattern. The H-11 doublet and H-12 doublet appear at ${\delta}$ 7.98 and 8.11, respectively. The $^{13}C$ NMR. spectrum showed a tetrasubstituted with a methylenedioxy group at C2 and C3, and two methoxy groups at C9 and C10. The chemical structure of the berberine was identified by $^1H$, $^{13}C$-nuclear magnetic resonance and electrospray ionization-mass spectroscopy spectral data analysis.

• School Mathematics
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• v.15 no.3
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• pp.551-568
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• 2013

The purpose of this study is to verify the research trends on 101 articles about mathematical creativity published in domestic journals. The analysis criteria are as follows: (1)What kind of terms the articles use to refer to the creativity in mathematics education, (2)Whether the researchers conceptualize such the terms or not, (3)Whether the definitions are domain-specific or not, (4)What perspectives, categories and levels of the articles have on creativity. The results of this study show the following. First, numerous articles used 'mathematical creativity' in order to point to the creativity in mathematics education. Second, among the 101 selected articles, 60 (59.4%) provided an explicit definition of the mathematical creativity and 19(18.8%) provided an implicit definition. Among the 79 articles, only 43(54.4%) provided domain-specific definitions. Second, the percentage of articles preferring one perspective over the other 3 perspectives were similar. Third, the rate of articles which focused on press(environment) of all categories (person, process, product, press) was low. Fourth, regarding the levels of creativity, most articles were done on little-c creativity level, on the other hand, the articles having an interest in mini-creativity were very rare. Based on these results, necessities of explicit and domestic-specific definition, whole approach of mathematical creativity, and articles focusing on the mini-creativity level should be reported.

• Journal of the Korean Geotechnical Society
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• v.28 no.8
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• pp.5-19
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• 2012

Vertical drains along with the preloading technique have been commonly used to enhance the consolidation rate of dredged placement formation. In practice, vertical drains are usually installed in the process of self-weight consolidation of a dredged soil deposit because this process takes considerable time to be completed, which makes conventional analytical or numerical models difficult to quantify the consolidation behavior. In this paper, we propose a governing partial differential equation and develop a numerical model for 2-D axisymmetric non-linear finite strain consolidation considering self-weight consolidation to predict the behavior of a vertical drain in the dredged placement foundation which is installed during the self-weight consolidation. In order to verify the developed model in this paper, results of the numerical analysis are compared with that of the lab-scaled self-weight consolidation test. In addition, the model verification has been carried out by comparing with the simplified method. The comparisons show that the developed model can properly simulate the consolidation of the dredged placement formation with the vertical drains installed during the self-weight consolidation. Finally, the effect of construction schedule of vertical drains and of pre-loading during the self-weight consolidation is examined by simulating an imaginary dredged material placement site with a thickness of 10 m and 20 m, respectively. This simulation infers the applicability of the proposed method in this research for designing a soil improvement in a soft dredged deposit when vertical drains and pre-loading are implemented before the self-weight consolidation ceases.

• Korean Journal of Social Welfare
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• v.66 no.1
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• pp.191-219
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• 2014

The major purpose of this study was to explore care giving experiences of mothers, who have their children with borderline intellectual functioning disorder. The core analytical strategy was to find out the essential meaning of caring their children. For this purpose, eight mothers were participated in depth interview, which conducted during October, 2011 through July 2012. The face-to-face interview repeated two or three times based on phenomenological perspective. The interview suggested two major findings: changing mother's view from raising retarded children to caregiving a child with growing-up substantially slow speed; the essence of nurturing experiences for mothers, whose children have borderline intellectual functioning, was to watching with attention rather than advocating ownership. This result can be also found in Barshow's concept of 'watching' rather than 'possession', which is suggested by Tennyson. However, the essential meaning of this concept was associated with 'watching with care', which was originated form Goethe's notion of 'existence'. Mother's of children with borderline intellectual functioning have reached a point of view: when creating a parent-child relationship, it was essential that the child was not 'my child', but was 'a child' per se. This type of parent-child relationship was a result of giving up a desire that the child raised within mother's boundary. It was also a result of psychological warfare and conflict in mother's mind. To internalized this view, it is recommended that the mothers implement the following three perspectives: first, the mothers put down overly-pushed motive toward their children; second, they enhance their level of understanding toward their child; third, it is necessary that the mothers build a new sense of existence through matching their level of concern with their children.

• Journal of Digital Contents Society
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• v.17 no.3
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• pp.143-155
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• 2016

In this study, we focused on the importance of politicians' voices in sending a message. Different factors for a voice may play different roles in sending a message and affect message recipients' responsiveness, understanding, and so on. For this reason, it can be said that an analytical study on voices in sending a diversity of messages is a meaningful attempt. We took interest in politicians' voices because we determined that a voice should be very important to politicians frequently sending a message through speech to the nation and others. This study aimed to investigate the voices of politicians, who represent their nation. We intended to select politicians representing ROK(Republic of Korea; South Korean) and USA(United States of America), choose representative speeches to the nation, make a comparative analysis of their voices in the speeches, and draw implications. We analyzed a total of eight voices - four ROK politicians and four USA ones, male and female - to characterize them and suggest guidelines for a voice with clearer message delivery. We analyzed the politicians' voices on the basis of such vocal properties as vocal pitch, accuracy of pronunciation, resonance, and intonation variation and found that the ROK politicians were somewhat poorer at utilizing their voice than the US ones. In particular, they were remarkably poorer at accurate pronunciation, which exerts a significant impact on message passing.