• The Journal of Korean Academy of Prosthodontics
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• v.55 no.2
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• pp.151-155
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• 2017

Purpose: The aim of this study was to evaluate screw removal torque of the two-piece zirconia abutment with the novel titanium component compared to the conventional one-piece titanium abutment in the internal connection implant before and after dynamic cyclic loading. Materials and methods: Two types of the abutment assemblies with internal connection were prepared and divided into the groups; titanium abutment-titanium abutment screw assemblies as control, and zirconia abutment-titanium socket-titanium abutment screw assemblies as experimental group. A total of 12 abutments and implants were used of six assemblies each group. Each assembly was tightened to 30 Ncm. A cyclic load of 300 N at an angle of 30 degrees in reference to the loading axis was applied until one million cycles or failure. The removal torque values (RTVs) of the abutment screws were measured with a digital torque gauge before and after cyclic loading. The RTVs of the pre load and post load were analyzed with t-test, and P-values < .05 were considered statistically significant. Results: The assemblies of both groups survived all after the dynamic cyclic loading test without screw loosening. The statistically significant differences were found between the mean RTVs before and after the cyclic loading in both groups (P < .05). The RTV differences for the control and the experimental group were $-7.25{\pm}1.50Ncm$ and $-7.33{\pm}0.93Ncm$, respectively. Statistical analysis revealed that the RTV differences in both groups were not significantly different from each other (P > .05). Conclusion: Within the limitation of this study, the two-piece zirconia abutment with the titanium component did not show a significant RTV difference of the abutment screw compared to the titanium abutment after dynamic cyclic loading.

• Korean Journal of Social Welfare
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• v.65 no.4
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• pp.165-193
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• 2013

This study purposes to explore the growing process through spousal bereavement in later life, and to develop the theory. A qualitative research was conducted, and the participants were 17 seniors. The analysis according to Strauss and Corbin's grounded theory(1998), resulted in 143 concepts, 43 subcategories, and 19 categories. Range analysis according to paradigm showed that the causal conditions were 'marital relationships', 'independent/dependent tendencies', and 'emotional readiness for the death of a spouse', and the phenomena were 'depression', 'hopelessness', 'daily stress', 'psychological intimidation', 'regret', and 'sense of being freed'. The contextual conditions that affect these phenomena were 'desire for intimate personal relationships' and 'desire to maintain independence'; the action/interaction strategies to manage the phenomena were 'facing reality' and 'efforts for construction of the new life'; and the mediating conditions that promote or suppress these action/interaction strategies were 'social support' and 'spirituality'. The results were 'reconstruction of the meaning in life', 'increase in self-esteem', 'reinforcement of social network' and 'embrace and acceptance'. Furthermore, when personal growth after bereavement of a spouse was analyzed focusing on changes over time, the growth process consisted of three steps: 'sadness and despair', 'embracing and moving forward', and 'personal growth'. The pattern analyses were performed to typify recurring relations by category, and 5 types were derived. The results of our study show that personal growth after spousal loss is an integrative process in life after crisis, and can be conceptualized as the process of overcoming the despair that immediately follows the death of a spouse, seeking a new life by actively taking control, and discovering a strengthened self.

• Journal of the Economic Geographical Society of Korea
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• v.14 no.3
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• pp.241-262
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• 2011

The aim of this study is to examine the changes of institution, quantity and approach methods of research results in the history of Korean economic geography during the last fifty-five years (1956-2010) and to offer the preparations for the future research. The history Korean economic geography can be divided into four periods: 'period of cradle' (1956-1962), 'period of establishment' (1963-later 1970s)', 'period of leap (the former half of 1980s-the former half of 1990s)', and 'period of transition (since later 1990s)'. Many departments of geography education and geography have been founded in the 'period of establishment' and 'period of leap'. Among the total research matters (1,621), 44.4 percent of research results have been made in 2000s and the most researched field was that of manufacturing geography, which occupied 27.7 percent. In the approach methods, about two-thirds of the results are the empirical inductive approach and the research frameworks method which clarified the regional structures and theory of spatial system occupied each about 40 percent. In the future, each research field of Korean economic geography is expected to take more serious view of nature environment, thorough regional survey, and preference of economy-society-culture-knowledge in the research framework of spatial network theory.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.11
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• pp.1695-1700
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• 2014

Oriental herbal liquor (Yakju) is a type of Korean traditional alcoholic beverage that uses Nuruk and oriental herbs for fermentation. The purpose of this study was to develop cosmetic ingredients using Jubak, which is a by-product of alcoholic fermentation of oriental herbal liquor. To investigate antioxidant, whitening, and anti-aging effects of Jubak, we prepared extract of Jubak and its solvent fractions. Ethyl acetate fraction (KSD E4-3) showed the most prominent free radical [1,1-diphenyl-2-picrylhydrazyl (DPPH)] scavenging activity ($SC_{50}$: 0.75 mg/mL). KSD E4-3 significantly inhibited in vitro mushroom tyrosinase activity ($IC_{50}$: 0.82 mg/mL) and reduced the melanin contents in mouse melanoma melanocyte, B16F10 cells. KSD E4-3 down-regulated protein expression of tyrosinase related proteins (TRP)-1, -2, which play key roles in melanogenesis. For anti-aging effects, inhibition of matrix metalloproteinase (MMPs) expression was evaluated using human keratinocyte, HaCaT cells. Treatment of HaCaT cells with KSD E4-3 reduced expression of MMP-1, -2, -9 and inhibited proteolytic activities of MMP-2, -9. These results suggest that KSD E4-3 induces down-regulation of cellular melanogenesis and protects against photoaging induced by UVB-induced damage. Thus KSD E4-3 could potentially be a valuable cosmetic ingredient.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.2
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• pp.427-435
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• 2017

Korea's overseas construction awards reached US $750 bn for more than 50 years since it first entered the market in 1966. In particular, the company won US $540 bn over 10 years from 2007, achieving 72% of the total contracts. However, in recent two years, awarded amounts have decreased by 40% each year. The most significant decline is due to the impact of international oil prices, which have plummeted since end of 2014, as oil-producing nations, which are Korea's major target countries, are struggling to cancel or postpone infrastructure orders. In order to lessen the impact of raw material price fluctuations, the recent trend is that even countries with relatively loose government financing conditions are rapidly changing their ordering methods to investment development forms such as PPP. The Korean government and companies have been already preparing for this for several years, but they are still not doing so well. The main reason is the lack of understanding about the investment development type project, especially financing methods and the aggravated fear of exposing it to various risks due to the characteristics of the development project, which takes a long time to collect the investment. In this paper, I propose a more systematic solution to financial process and risk management, which is recognized as a obstructive factor for Korean companies, in line with the recent government-led establishment of overseas infrastructure development support organizations. I would like to serve as a investment guide.

• Journal of Science Education
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• v.37 no.3
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• pp.550-561
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• 2013

The purpose of this study was to explore the effect of science academic achievement, inquiry ability, scientific attitude of students using the STEAM Learning Program. To verify about the effects of science-based STEAM program, a teaching plan and worksheet for students based on STEAM has been constructed and applied. The subjects of this program were the first grade students of both an experimental class(34 students) and a comparative class (34 students) located in Kyonggi Province. The results of this study were as follows: First, there is a significant difference in inquiry ability between two groups. STEAM Learning program accomplished higher achievement than traditional science instruction. Second, STEAM Learning program influenced science academic achievement positively. Third, there is a statistically significant effect on scientific attitude of students than traditional instruction. In conclusion, the STEAM Learning Program was useful to develop the elementary school student's inquiry ability, scientific attitude.

• Journal of the Korean Society for Library and Information Science
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• v.39 no.3
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• pp.105-119
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• 2005

With the introduction of Internet-based education such as online learning and virtual campuses. there are increased interests and demands for electronically delivering educational contents in comparison to the traditional educational methods. Our preilminary study showed that approximately $50\%$ of virtual groups formed online for the scope of collaborative learning encountered harriers that prevented them from forming an effective learning team and making satisfactory progress toward reaching the learning objectives. In this study, we asked the undergraduate students. who were the members of the online learning team, to work on the given discussion topics through the use of emails and threaded discussion boards. Then. we investigated the roles played by two electronic communication medium during the virtual discussion with respect to the learning outcome. We also studied how information was shared amongst the virtual learning team members. The results of our study showed that the email based online learning had the advantage of individualized and friendly information transfer. However. it also caused certain difficulty in exchanging ideas due to the one-sided nature of the email-based communication. On the other hand, the threaded discussion board provided easier information sharing and broadcasting. which enabled active participation by the virtual team members. However. It also had the disadvantage of difficulty in accurate information conveyance and duplication of the posted information. In summary, our study results showed that there was a high correlation between the characteristics of the electronic communication medium and the decision that the online learners made regarding which medium to use. There was a high correlation between the type of the electronic communication medium and the online learners' experiences in using these media.

• Journal of Educational Research in Mathematics
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• v.18 no.3
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• pp.407-434
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• 2008

This research is to analyze the descriptions in the statistic chapter of the grade 7's current textbooks. The analysis is based on the distribution concepts suggested by Nam(2007). Thus we assumed that the goal of this statistic chapter is to establish concepts on the distributions and to learn ways of communication and comparison through distributional presentations. What we learned and wanted to suggest through the study is the followings. 1) Students are to learn what the distribution is and what are not. 2) Every kinds of presentational form of distributions is to given its own right to learn so that students are more encouraged to learn them and use them more adequately. 3) Density histogram is to be introduced to extend student's experiences viewing an area as 3 relative frequency, which is later to be progressed into a probability density. 4) Comparison of two distributions, especially through frequency polygons, is to be an hot issue among educational stakeholder whether to include or not. It is very important when stochastic correlations be learned, because it is nothing but a comparison between conditional distributions. 5) Statistical literacy is also an important issue for student's daily life. Especially the process ahead of the data collection must be introduced so that students acknowledge the importance of accurate and object-oriented data.

• International Journal of Highway Engineering
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• v.13 no.2
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• pp.31-39
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• 2011

More than sixty percentage of highway in South Korea were constructed by concrete pavements and more than half of the concrete pavements were twenty years or older. Maintenance and rehabilitation of aged cement concrete pavements required early transportation opening due to difficulty of preparing bypass roads, given South Korea's transportation condition and so far, mostly asphalt concrete overlay has been used. However, asphalt concrete pavement maintenance and rehabilitation is costly because of early damage and at the same time, it causes inconvenience to the road users. Recently, as an effective method of rehabilitation for aged cement concrete pavement, bonded concrete overlay is being attempted. Therefore, utilizing various data on year-by-year basis is needed to rationally analyze of the damage on asphalt concrete overlay and bonded concrete overlay is necessary. However, in South Korea database of Serviceability damage on asphalt concrete overlay and bonded concrete overlay does not exist. In this research, performance is evaluated by the LTPP (Long Term Pavement Performance) Data of U.S.A, which accumulated various damage data of asphalt concrete overlay and bonded concrete overlay. However, the pattern distress of asphalt concrete overlay and bonded concrete overlay are different. Therefore, the pavement distress data of each section is collected into database and distress are calculated PCI(Pavement Condition Index) in order to compare life of asphalt concrete overlay and bonded concrete overlay.

• Korean Security Journal
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• no.41
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• pp.327-356
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• 2014

The ultimate goal of the local government is the owner of the residents welfare of the community. Welfare of the residents will start from the protection of life and property of the inhabitants. Much of this protective activity is a function of the police. Therefore, to be a municipal & local police that is based on the autonomy of the local conceptual prerequisites for the welfare of the population. Municipal & local police activities are activities for the local community rooted in the community that the police and to rejoin the community, municipal & local police activities taking place in the center of the area to solve the problem, but to reduce the fear of crime and disorder, crime as an expression of the efforts of the local residence themselves to improve the overall quality of life of the community as a partner recognition local residents. Municipal & local police in this case be introduced across the board in the central and local governments is careful review of the various alternatives been prepared on analysis is crucial to reduce the trial and error by providing the best alternative. priority should be to figure out exactly what the reason to introduce a municipal police. in other words, the introduction of the municipal & local police in the central and local governments, state police and municipal & local police, the ruling party and the opposition, regional self-government initiative unseen conflict between organizations and local governments are not welcomed by local residence in local time truly 'safe' and will have to face that the 'improve quality of life'.