• The Mathematical Education
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• v.40 no.1
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• pp.77-92
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• 2001

In this study, the number of theses conducted in 1990's for the master's degree in mathematics education was investigated in terms of their fields and themes. These theses were analysed as to how much they had been studied according to the field and whether they had conformed to the expectations and requirements for research in mathematics education under the current educational curriculum. Futhermore, this study aimed to discover advancing directions of research in mathematics education. The results are as follows: First, the rate of annual thesis presentations decreased as many as 3.82% in 1994 compared with the previous year, but the rate increased steadily in the other years showing an overall annual average increase of 8.41%. Second, in the geographical distribution of thesis presentations among local provinces, Seoul represented the highest frequency at 41.13% and Cheju Island the lowest at 1.68%. When the annual thesis presentations were analysed among regions, their number increased steadily in Seoul, but fluctuated in most other regions. Third, regarding study themes, theses on mathematics education formed 70.91% of the total while those focusing on pure mathematics formed 29.09%. Among the theses of mathematics education, most were based on teaching curriculums and the least were based on education assessment. Among the theses on teaching curriculum, teaching analytics formed the highest rate. Theses on education technology, such as computerizing and computing, have shown to be increasing annually and formed 8.95% of the total in 1999. The study also indicated that especially in the late 1990's, there have been many designed programs based on the Web, like JAVA and CGI, and studies on teaching and teaming methods using the internet.

• Hwankyungkyoyuk
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• v.23 no.1
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• pp.36-49
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• 2010

The purpose of this study was to investigate whether elementary school parents' environmental literacy varied according to independent variables, to verify specific variables that affected their environmental literacy, and to analyze the correlation between elementary school students' and their parents' environmental literacy. Twelve elementary schools in Seoul and Gyeonggi-Do were chosen for purposive sampling. 342 questionnaires were used for analysis among the 350 questionnaires collected during the study, and their environmental literacy was measured through 55 questions consisted of 12 items for knowledge category, 22 for attitude category, 5 for behavior category, and 3 for skills category with 16 demographic variables. Statistical analysis was conducted on each of the variables that make up environmental literacy through mean t-test, F-distribution, Scheffe test, and Pearson correlation. The results of this study were as follows. (1) there is the difference according to age and career in parent's actual environmental literacy, but there is no difference in geneder, birthplace, residential type, religion and income. The parents in forties scored significantly higher than parents in thirties in subdomains of environmental skill and environmental interest in environmental literacy. And the parents with bachelor's degree scored significantly higher than parents with at least a high school diploma in subdomains of ecological knowledge, knowledge on environmental problems & issue, environmental skill and environmental behavior. (2) the most influential media on parents' environmental literacy is TV, then newspaper, internet and book follow. (3) the correlation between environmental crisis and environmental interest is the highest, but the mainly negative correlation is analysed between knowledge subdomains and other subdomains. (4) there is the correlation between elementary school students' and their parents' environmental literacy.

• Korean Journal of Medicinal Crop Science
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• v.23 no.1
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• pp.8-12
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• 2015

Characteristic of seed for Sageretia thea fruits collected from the habitat of harvest season in Jeju and their germination ratio in different temperatures were considered. The average weight was 0.2 g, average diameter was 7.2 mm, average length was 6.5 mm, and size distribution range was 5.1 ~ 10.0 mm. The number of seeds per fruit was 1.8, and 1000 grain weight was 7.77 g with diameter of 3.7 mm and thickness of 1.7 mm in size. The fruit maturation was investigated to be from April 27 to June 1, when the best maturation period was about a week, May 11 to May 18. Also, the fruits grown on May 4 to May 11 were seen to have the bigger in transverse size and weight with a tendency of the earlier maturation date has the greater the number of seeds. S. thea seeds pretreated for 24 hours at $50^{\circ}C$ were not germinated, while most of those pretreated for 24 hours at $4^{\circ}C$ were successfully germinated at any degree of temperature (except at a temperature of $10^{\circ}C$). Particularly, the highest germination rate of 55% was made at $15^{\circ}C$, and plumule and radicle were best grown within the temperature range of $25^{\circ}C$.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.3
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• pp.325-336
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• 2006

The presence of volatile organic compounds (VOC), produced and released from both anthropogenic and natural sources, can accelerate the degradation of air quality in the surrounding area. In this study, we investigated the emission concentrations of VOC based on a total of 115 sample analysis made from 47 companies (representing 17 types of industry) at the Ban Wall industrial complex (Jun. 2004 to Jan. 2005). Through a statistical analysis of these measurement data, we inspected the emission characteristics of VOC in relation with industrial type and processing unit. When these data were compared each other, toluene was found to record the highest value of 423 ppb followed by ethylbenzene (68.3 ppb), m, p-xylene (43.6 ppb), o-xylene (27.2 ppb), styrene (23.9 ppb), and benzene (16.4 pub). In addition, by converting these VOC concentration data into malodor intensity, we attempted to account for their distribution patterns in terms of relative contribution to the malodor formation. The results of odor intensity conversion generally indicated that the odor intensities of individual VOC do not exceed the degree of 1. When our VOC results were compared against other odorous compounds measured concurrently, the results were highly contrasting each other. Despite relative insignificance as odorous compounds, these VOCs are generally found ubiquitously and in abundant quantities in this strong source area.

• Journal of Microbiology and Biotechnology
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• v.16 no.9
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• pp.1369-1376
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• 2006

Self-organized nanogels were prepared from pullulan/biotin conjugates (PU/Bio) for the development of an effective anticancer drug delivery system. The degree of biotin substitution was 11, 19, and 24 biotin groups per 100 anhydroglucose units of pullulan. The physicochemical properties of the nanogels (PU/Bio1, 2 and 3) in aqueous media were characterized by dynamic light scattering, transmission electron microscopy, and fluorescence spectroscopy. The mean diameter of all the samples was less than 300 nm with a unimodal size distribution. The critical aggregation concentrations (CACs) of the nanoparticles in distilled water were $2.8{\times}10^{-2},\;1.6{\times}10^{-2}$, and $0.7{\times}10^{-2}mg/ml$ for the PU/Bio1, 2, and 3, respectively. The aggregation behavior of the nanogels indicated that biotin can perform as a hydrophobic moiety. To observe the specific interaction with a hepatic carcinoma cell line (HepG2), the conjugates were labeled with rhodamine B isothiocyanate (RITC) and their intensities measured using a fluorescence microplate reader. The HepG2 cells treated with the fluorescence-labeled PU/Bio nanoparticles were strongly luminated compared with the control (pullulan). Confocal laser microscopy also confirmed internalization of the PU/Bio nanogels into the cancer cells. Such results demonstrated that the biotin in the conjugate acted as both a hydrophobic moiety for self-assembly and a tumor-targeting moiety for specific interaction with tumor cells. Consequently, PU/Bio nanogels would appear to be a useful drug carrier for the treatment of liver cancer.

• Magazine of the Korean Society of Agricultural Engineers
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• v.39 no.3
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• pp.72-82
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• 1997

In all inelastic deformations time rate effects are always present to some degree. Whether or not their exclusion has a significant influence on the prediction of the material behaviour depends upon several factors. In the study of structural components under static loading conditions at normal temperature it is accepted that time rate effects are generally not important. However metals, especially under high temperatures, exhibit simultaneously the phenomena of creep and viscoplasticity. In this study, elastoplastic and elasto-viscoplastic models include nonlinear geometrical effects were developed and several numerical examples are also included to verify the computer programming work developed here in this work. Comparisons of the calculated results, for the elasto-viscoplastic analysis of an internally pressurised thick cylinder under plane strain condition, have shown that the model yields excellent results. The results obtained from the numerical examples for an elasto-viscoplastic analysis of the Nuclear Reinforced Concrete Containment Structure(NRCCS) subjected to an incrementally applied internal pressure were summarized as follows : 1. The steady state hoop stress distribution along the shell layer of dome and dome wall junction part of NRCCS were linearly behave and the stress in interior surfaces was larger than that in exterior. 2.However in the upper part of the wall of NRCCS the steady state hoop stress in creased linearly from its inner to outer surfaces, being the exact reverse to the previous case of dome/dome-wall junction part. 3.At the lower part of wall of NRCCS, the linear change of steady state hoop stress along its wall layer began to disturb above a certain level of load increase.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.8
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• pp.297-308
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• 2020

This study exemines the roles of corporate social activity (CSR) and executive compensation structure on the pricing of seasoned equity offerings (SEOs) with special focus on the role of CSR in reducing the level of information asymmetry between managers and future shareholders of issuing firms through SEOs. This study also investigates the interaction between executive compensation structure and CSR on the discounting of SEOs. We use a sample of 2,102 seasoned equity offerings of U.S. firms with CSR scores from 1995 to 2015 in our OLS fixed effect regression analysis. The results show that issuing firms with high CSR are more likely to expericence a lower degree of the SEO discount. The results also document a positive association between CSR and a high proportion of equity-based compensation of issuing firms' executives. The findings of this paper confirm that CSR attenuates the impact of information asymmetry and the pre-SEO price uncertainty on the pricing of the offers and hence the SEO discount. Furthermore, CSR reinforces the impact of executive firm-related wealth on the discounting of seasoned equity offerings. It appears that firm-related wealth motivates managers to actively engage in reducing information asymmetry activities before SEOs, thereby decreasing the SEO discount.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.2
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• pp.39-44
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• 2017

In this study, we compared the perception of absolute purchase of equipment for broadcasting equipment purchasing demand according to the rapid change of domestic content production and distribution method, and the degree of information such as technical reliability and system stability of domestic broadcasting equipment perceived by consumer The effects were analyzed through a research model. Due to the lack of existing research data on broadcasting equipment demand, we conducted in depth interviews with surveys of broadcasting equipment and surveys. As a result of analysis, compared to foreign equipments, there are many cases of purchase of domestic equipments, systems, and block purchases. To improve the preference and satisfaction of Korean broadcasting equipment, which is recognized by domestic demand for broadcasting equipment, it is urgent to improve the technical reliability and to develop core key equipment and to expand the demand of domestic equipment limited to small power transmitter antenna and monitor equipment. It is urgent to develop in order to develop overseas and to support the domestic market to secure the domestic market.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.28 no.3
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• pp.118-122
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• 2018

Ceria ($CeO_2$) is a rare earth oxide, which has been widely investigated to improve the property. It is important to increase the surface area of $CeO_2$, because high surface area of $CeO_2$ can improve the catalytic ability. $CeO_2$ nanoparticles were synthesized by a solvothermal process. A discussion on the influence of solvent ratio and precursors on $CeO_2$ nanoparticles was performed. The size and degree of the agglomeration of the synthesized $CeO_2$ could be tuned by controlling those parameters. The average size and distribution of prepared $CeO_2$ powders was in the range of 3 to 13 nm and narrow, respectively. The XRD pattern showed that the synthesized $CeO_2$ powders were crystalline with cubic phase of $CeO_2$. The average particle size was calculated by Scherrer equation and FE-TEM images. The morphology of the synthesized $CeO_2$ particle was objected using FE-TEM and FE-SEM. Specific surface area of the synthesized $CeO_2$ was determined using BET (Brunauer-Emmett-Teller) equation.

• Journal of Acupuncture Research
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• v.18 no.5
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• pp.11-23
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• 2001

Objective : This study is designed to evaluate the clinical effect of the oriental medical treatment (Ex: chuna, physical theraphy, acupuncture, moxibustion, herb medicine, etc.) on patient of scoliosis. Methods : We investigated 12 patients with scoliosis who visited to Department of Acupunture & Moxibustion, Tae gu Oriental Hopital of Kyung San University from January 2000 to September. 12 patients had a diagnosis of scoliosis by X-ray. We treated 12 patients by the oriental medical treatment (Ex: chuna, acupuncture, physical theraphy, moxibustion, herb medicine, etc.)and they were evaluated with post treatment X-ray findings. Results : 1. We investigated 6 female and 6 male patients. The most commom distribution of age was 30's. 2. In the scoliosis angle : before treatment, the average scoliosis angle was $13.56^{\circ}$ but after treatment, it was decreased to $9.31^{\circ}$ and the mean correctability was 33.47%. 3. The more servious the symptoms were, the lesser the correction rate was. It was decreased in the order of Gr I, Gr II, Gr III and Gr IV. 4. The larger the scoliosis angle and the degree of rotation were, the lesser the correction rate was. Conclusion : These results suggest that the oriental medical treatment (Ex: chuna, acupuncture, physical theraphy, moxibustion, herb medicine, etc.) was effective treatment modality on patient of scoliosis.