• The Journal of the Korea Contents Association
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• v.14 no.6
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• pp.367-384
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• 2014

This study addresses an empirical issue which has been received little attention in the contemporary finance literature: To identify any financial determinants of the profitability indices for the firms belonging to the Korean chaebol. Three hypotheses of concern were postulated and tested for the sample firms covering the periods of the pre-and post-financial global crises. Regarding the results on the 1st hypothesis test of characterizing any financial profiles for the firms (belonging to the chaebols) by estimating a legitimate panel data model: the present study found the statistically significant relationships of the explanatory variables (BVLEVl, MVLEVl, MV/BV, RISK, FCFF and FOS) with the book-value based profitability ratio: while the market-valued profitability index was explained only by BVLEV2. Regarding the 2nd hypothesis test for the profitability of the sample firms at the industry level: the chaebol firms in the chemical and the food industries overall positioned themselves into the top ranks in order, which was tested by the ANCOVA and the Tukey multiple comparison procedure. Finally: on the 3rd hypothesis test for the 'adjusted' Dupont system, only two such as the 'operating margin' and the 'asset turnover' showed their significant effects between the chaebol firms and their counterparts in both the (parametric) independent samples t-test and the (nonparametric) Wilcoxon-Mann-Whitney statistics.

• Journal of Korea Multimedia Society
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• v.13 no.8
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• pp.1183-1193
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• 2010

The pyramid graph is well known in parallel processing as a interconnection network topology based on regular square mesh and tree architectures. The enhanced pyramid graph is an alternative architecture by exchanging mesh into the corresponding torus on the base for upgrading performance than the pyramid. In this paper, we adopt a strategy of classification into two disjoint groups of edges in regular square torus as a basic sub-graph constituting of each layer in the enhanced pyramid graph. Edge set in the torus graph is considered as two disjoint sub-sets called NPC(represents candidate edge for neighbor-parent) and SPC(represents candidate edge for shared-parent) whether the parents vertices adjacent to two end vertices of the corresponding edge have a relation of neighbor or sharing in the upper layer of the enhanced pyramid graph. In addition, we also introduce a notion of shrink graph to focus only on the NPC-edges by hiding SPC-edges within the shrunk super-vertex on the resulting shrink graph. In this paper, we analyze that the lower and upper bounds on the number of NPC-edges in a Hamiltonian cycle constructed on $2^n{\times}2^n$ torus is $2^{2n-2}$ and $3{\cdot}2^{2n-2}$ respectively. By expanding this result into the enhanced pyramid graph, we also prove that the maximum number of NPC-edges containable in a Hamiltonian cycle is $4^{n-1}$-2n+1 in the n-dimensional enhanced pyramid.

• Journal of The Korean Association of Information Education
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• v.20 no.2
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• pp.139-150
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• 2016

The development of Smart devices has become a key influence on the changes of the school system. As Smart education is integrated and institutionalized in school systems, how it is perceived and utilized by teachers should be investigated. This study is conducted to find out the perception of the teachers on characteristics of Smart education, using qualitative research method, and to analyze importance-performance, using additional quantitative analysis. To figure out the perceptions of the attributes of Smart education by teachers, related literatures were reviewed. The 8 teachers were selected and the data on their perceptions of Smart education were collected through direct observation of class and semi-structured in-depth interview. After researching, we finally drew out 16 final concepts, 6 sub-categories, and 3 categories in the open coding process. Based on the 16 concepts on teachers' perceptions on Smart education, importance-performance analysis (IPA) were conducted to identify areas that need focus and improvement. Based on the results of teachers' perceptions on importance of and the levels of use of Smart education, recommendations were provided for better practice of Smart education in school.

• Journal of Korea Port Economic Association
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• v.36 no.1
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• pp.59-76
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• 2020

The purpose of this study is to analyze the factors of the main selection criteria of the contract form used to conclude the sales contracts of used ships and to assist parties in selecting the most suitable contract form for trading situations. The methods of the study are based on identifying the factors from the questionnaires using analytic hierarchy process analysis, following the selection of typical details through interviews with the S&P Broker Group and finding the solutions that match each detail. The analysis shows that ship traders prefer the Norwegian Sales Form (NSF) to NIPPONSALE for various reasons. Considering the sellers' situations, NFS is the more reasonable option for major countries, except Japan. NIPPONSALE is relatively more focused on the advantages of the buyer's conditions, including for Japan. It is important to select the appropriate clauses from these types of contract, according to the trading conditions, including the main and additional terms, in order to create a mutual agreement between the shipper and the consignee that leads to more cooperation and balances the purposes of both parties in adjusting the time for securing and disposing of the vessels.

• Journal of the Mineralogical Society of Korea
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• v.19 no.4 s.50
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• pp.311-324
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• 2006

In the Pohang-Gampo area, several diatomite beds occurred in mostly thinner than 1 m are embedded in the Pohang Formation of marine environment and the pyroclastic Eoil Formation. The diatomite from the Eoil Formation is constituting the high-grade ore altered slightly by diagenesis. In contrast, the diatomite intercalated within the upper horizon of the Yeonil Group is comparatively low-grade and highly altered in places. During diagenesis, an increasing of crystallinity of opal, i.e., the original mineral component of diatom, results in ultimately the mineral transition to quartz with accompanying a drastic change in morphology and texture of the altered diatomite. The diagenetic alteration appears to have undergone by way of the chemical diagenesis, which is largely controlled by degree of fluid contact, rather than burial diagenesis. For the diatomite from the Pohang-Gampo area, careful SEM observations, XRD, chemical analyses, and determination of specific surface area were done to identify the fossil species, mineral and chemical composition, and other physical properties in the view of assesment of grade and quality. The domestic diatomite ores are evaluated to be not good in grade and quality, compared to those of famous foreign localities. However, some diatomite deposits of marin,: origin from the Pohang Formation is constituting a peculiar clay-rich type, i.e., moler applicable to the special usage such as a manufacturing of lightweight brick. Because such a diatomite is frequently intercalated relatively as a thicker bed in the upper part of the Yeonil Group, a systematic and careful investigation should be done for the exploitation and development of an economic diatomite deposit of the moler type.

• Korean Journal of Environmental Biology
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• v.17 no.1
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• pp.1-9
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• 1999

Numerous observations revealed strong evidence of increased middle ultraviolet radiation or UV-B (280 ~ 320 nm) at the earth's surface resulting from stratospheric ozone depletion. UV is the waveband of electromagnetic radiation which is strongly absorbed by nucleic acids and proteins, thus causing damage to living systems. It has been recorded in the East Sea, Korea that solar UV-B impinging on the ocean surface penetrates seawater to significant depths. Recent researches showed that exposure to UV-B for as short as 2h at the ambient level (2.0 Wm$^{-2}$) decreased macroalgal growth and photosynthesis and destroyed photosynthetic pigments. These may suggest that UV-B could be an important environmental factor to determine algal survival and distribution. Some adaptive mechanisms to protect macroalgae from UV-damage have been found, which include photoreactivation and formation of UV-absorbing pigments. Post-illumination of visible light mitigated UV-induced damage in laminarian young sporophytes with blue the most effective waveband. The existence of UV-B absorbing pigments has been recognized in the green alga, Ulva pertusa and the red alga, Pachymeniopsis sp., which is likely to exert protective function for photosynthetic pigments inside the thalli from UV-damage. Further studies are however needed to confirm that these mechanisms are of general occurrence in seaweeds. Macroalgae together with phytoplankton are the primary producers to incorporate about 100 Gt of carbons per year, and provide half of the total biomass on the earth. UV-driven reduction in macroalgal biomass, if any, would therefore cause deleterious effects on marine ecosystem. The ultimate impacts of increasing UV-B flux due to ozone destruction are still unknown, but the impression from UV studies made so far seems to highlight the importance of setting up long-term monitoring system for us to be able to predict and detect the onset of large -scale deterioration in aquatic ecosystem.

• Korean Journal of Microbiology
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• v.31 no.4
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• pp.267-273
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• 1993

We screened promoters inducible by superoxide radical from Escherichia coli. For this. we constructed random promoter library from E. coli MG 1655 using a promoter-probing plasmid. pJAC4. Six hundred and sixty clones in this library were classified based on their promoter strength by ampicillin gradient plate assay. Three hundred and eighty three clones with relatively weak to medium promoter strength were selected and then screened for their inducibility by superoxide radical on ampicillin gradient plate containing paraquat. Three clones (clones 5. 15 and 34) were detected to be induced by paraquat treatment and the level of induction were between 1.4 and 4 folds. Comparison of nucleotide sequences of the cloned promoter fragment with registered sequences in GENBANK and EMBL databases suggests that the cloned DNA fragments have not been yet characterized in E. coli. Transcription start sites in these clones were determined by rrimer extension and S I nuclease protection analysis. S 1 analysis of clones 5 and IS indicated that the mRNA levels were increased by paraquat treatment. Especially. clone 5 \vas found to have two transcription start sites. the upstream start site of which was selectively used by paraquat treatment. Searching for promoter clements. we found that only the downstream promoter of clone 5 has -10 and - 35 promoter elements recognized by RNA polymerase ($E\sigma^{70}$) and the others have no conserved promoter elements. This suggests that these superoxideinducible promoters may require transcription initiation protein(s) other than $E\sigma^{70}$.

• Journal of The Korean Association For Science Education
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• v.20 no.4
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• pp.611-623
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• 2000

The cooperative learning movement began as parts of the desegregation process in America, aiming at increasing academic achievement and social skills among diverse students. Cooperative learning may be defined as a classroom learning environment in which students work together in small heterogeneous groups. Although many studies have shown the effectiveness of cooperative learning in a variety of subjects, relatively few have focused on biology. In this study, we investigated the effects of cooperative learning on students' achievement and attitude of middle school biology students. For this purpose this study compared three sections. In one section, a cooperative learning strategy was used. Second section was taught in small groups and the third section was instructed in the traditional method. The unit 'Structures and functions of animals' was used. A total of 188 students were included in this study. These classes were treated for 10hours during 10weeks from September 1 to November 28, 1999. The pretests-posttests control group design was applyed. An analysis of covariance(ANCOVA) was used as the data analysis procedure. Significant differences were found in the achievement and the attitude of students using cooperative learning strategy(p<.05) when compared to traditional classroom structure and small group learning. Cooperative learning was more effective in the low-ability and average-ability students than the high-ability students in the science achievement. Cooperative learning is effective in both male and female students. And students in the cooperative group achieved better than those in other groups in affective, behavioral, and intention-cognitive domain of science attitude.

• Journal of dental hygiene science
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• v.13 no.4
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• pp.440-448
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• 2013

The purpose of this study was to analyze the effects of perceived stress on dietary habits and oral health behaviors in Korean adolescents. Data were from the Korea Youth Risk Behavior Web-based Survey (KYRBS) in 2011. A total of 74,186 adolescents were surveyed using the self-administered questionnaire. Logistic regression analyses were performed to elucidate the effects of perceived stress on dietary habits and oral health behaviors. Statistical analyses were conducted, and p<0.05 were considered significant. We found that adolescents with higher stress were more likely to increase the risk of adverse dietary habits (low consumption of fruits, vegetables and milk, high consumption of carbonated soft drinks, fast food and cookie) compared to those with lower stress. Regarding the relationship between perceived stress and oral health behaviors, adolescents with higher stress were less likely to practice oral health behaviors such as brushing teeth after snack consumption and brushing teeth before sleep compared to those with lower stress. This result indicates that adolescents' perceived stress might play a significant role in the negative dietary habits and oral health behavior.

• KIPS Transactions on Software and Data Engineering
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• v.4 no.12
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• pp.549-560
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• 2015

There is a wide variety of data quality attributes such as the ones proposed by the ISO/IEC organization and also by many other domestic and international institutions. However, it takes considerable time and costs to apply those criteria and guidelines to real environment. Therefore, it needs to define data quality evaluation attributes which are easily applicable and are not influenced by organizational environment limitations. The purpose of this paper is to derive data quality attributes and order of their priorities based on customer requirements for managing the process systematically and evaluating the data quantitatively. This study identifies the customer cognitive constructs of data quality attributes using the RGT(Repertory Grid Technique) based on a Korean quality standard model (DQC-M). Also the correlation analysis on the identified constructs is conducted, and the evaluation attributes is prioritized and ranked using the AHP. As the results of this paper, the consistent system, the accurate data, the efficient environment, the flexible management, and the continuous improvement are derived at the first level of the data quality evaluation attributes. Also, Control Compliance(13%), Regulatory Compliance(10%), Requirement Completeness(9.6%), Accuracy(8.4%), and Traceability(6.8%) are ranked on the top 5 of the 19 attributes in the second level.