• The Journal of Korean Academy of Prosthodontics
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• v.58 no.3
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• pp.177-184
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• 2020

Purpose: The purpose of this study was to compare and evaluate the tensile bond strength of chairside reline resin to denture base resin fabricated by different methods (subtractive manufacturing, additive manufacturing, and conventional heat-curing). Materials and methods: Denture base specimens were fabricated as cuboid specimens with a width of 25 mm × length 25 mm × height 3 mm by subtractive manufacturing (VITA VIONIC BASE), additive manufacturing (NextDent Base) and conventional heat-curing (Lucitone 199). After storing the specimens in distilled water at 37℃ for 30 days and drying them, they were relined with polyethyl methacrylate (PEMA) chairside reline resin (REBASE II Normal). The subtractive and additive manufacturing groups were set as the experimental group, and the heat-curing group was set as the control group. Ten specimens were prepared for each group. After storing all bound specimens in distilled water at 37℃ for 24 hours, the tensile bond strength between denture bases and chairside reline resin was measured by a universal testing machine at a crosshead speed of 10 mm/min. The fracture pattern of each specimen was analyzed and classified into adhesive failure, cohesive failure, and mixed failure. Tensile bond strength, according to the fabrication method, was analyzed by 1-way ANOVA and Bonferroni's method (α=.05). Results: Mean tensile bond strength of the heat-curing group (2.45 ± 0.39 MPa) and subtractive manufacturing group (2.33 ± 0.39 MPa) had no significant difference (P>.999). The additive manufacturing group showed significantly lower tensile bond strength (1.23 ± 0.36 MPa) compared to the other groups (P<.001). Most specimens of heat-curing and subtractive manufacturing groups had mixed failure, but mixed failure and adhesive failure showed the same frequency in additive manufacturing group. Conclusion: The mean tensile bond strength of the subtractive manufacturing group was not significantly different from the heat-curing group. The additive manufacturing group showed significantly lower mean tensile bond strength than the other two groups.

• Journal of Dental Rehabilitation and Applied Science
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• v.24 no.4
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• pp.325-335
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• 2008

The junction between resilient denture liner and the denture base is difficult to finish and polish due to difference of the physical property of the materials. Gaps tend to be formed during finishing and polishing procedures. The purpose of this study was measuring the width of junctional gap between $Molloplast-B^{(R)}$ and denture base material after finishing and polishing procedure, and evaluating the effect of method and direction on gap width. $Molloplast-B^{(R)}$ was processed (according to the manufacturer's instruction) against Lucitone $199^{(R)}$ acrylic resin. 50 specimens were fabricated with a raised center section. All of specimens were examined and photographed with a stereoscopic microscope(x120), and the largest gap along the junction of $Molloplast-B^{(R)}$ and acrylic resin on each specimen was measured. One-way analysis of variance(ANOVA) and independent t-test at 95% confidence level were used to analyze the data and to compare groups. The results of this study were as follows. In comparison with finishing tools, the gap width was the largest in $Molloplast^{(R)}$-Cutter and the smallest in FSQ-cross cut bur. There was statistically significant difference between FSQ-cross cut bur and $Molloplast^{(R)}$-Cutter(p<0.05). There was no significant difference in gap width between the direction of polishing. The mean value of gap width was the smallest in case of no polishing, and the largest in case of polishing with pumice & tin oxide. There was statistically significant difference between pumice and pumice & tin oxide. From the results, it is concluded that the use of $Molloplast^{(R)}$-Cutter in clinic need serious consideration even though it has good cutting ability. Further careful study is needed for finishing and polishing methods for decreasing gap width in junction of two materials.

• Korea journal of population studies
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• v.28 no.2
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• pp.97-129
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• 2005

Korean society recently witnesses a rapid lllcrease of suicide across all ages. In particular, suicide in old ages jumps up ill a very unexpected way. Furthermore, the order of suicide in the cause of death across all ages is becoming higher and higher in Korea. This study provides details of suicide that occurs in Korean society with the comparison to that of Japan at the descriptive level. It is not well known why suicide in Korean surges recently. Several previous research show the possibility that surging suicide is closely related to the worsened economic conditions especially since the economic crisis in 1997. They adopt economic growth, unemployment rate, income distribution, household finance index as economic indicators in their research. This study also adopts those indicators and conducts a correlation analysis in two periods, 1990-1997 and 1998-2004. It is found that there is no correlation between economic indicators and suicide in the period of 1990-1997. On the other hand, there is a very strong correlation between income distribution and suicide in the period of 1998-2004. Other economic indicators except income distribution does not have any significant correlation with suicide. This finding suggests that currently increasing suicide in Korea may be a result of economic polarization, which has been worsened since the economic crisis in 1997.

• Journal of Korean Home Economics Education Association
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• v.21 no.4
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• pp.71-89
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• 2009

The purpose of this paper was to suggest effective management of clothing department in vocational high schools. Bibliographic research on ten vocational high schools' clothing departments was done. Also a survey was done to figure out what students and teachers think of clothing department education. The results were as follows. There are ten clothing departments in vocational high schools countrywide. 1493 students are enrolled in the department and they are taught by 51 teachers. Each school has two to seven laboratories. Professional subject time assignment of clothing department varies from 82 to 112 hours. Students chose clothing department in order to enter the university and their satisfaction on the department was "fair." Students' satisfaction level of professional education courses was "fair" and they felt difficulties both in theory and practice. Students answered that Embroidery/Knitting courses should be closed and Fashion Coordination be opened. Students were "fairly" satisfied with facilities for practice and felt job training was necessary. Most of them wanted to enter university after high school graduation. Teachers answered professional education curriculum was "fair." They found it necessary to improve the textbooks and felt both theory and practice difficult. They wanted Embroidery/Knitting courses to be closed and Fashion CAD course to be installed. From the teachers' view, students' prospect was better to enter university than to get a job. Teachers suffered from too much teaching-unrelated workload and wanted the number of teachers to be increased. Considering the above results, vocational high schools should concentrate their efforts on making students continue to study by extending the way to enter the same department of university as department of vocational high schools. In addition, they should develop various practice programs through field practice and educational-industrial relationship to help students get jobs. Both teachers and students think that the clothing department curriculum is difficult now. Therefore, the level of the curriculum should be adjusted. Finally, it was necessary to increase the number of teachers and to carry out teachers' training to raise quality in education.

• 대한공업교육학회지
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• v.44 no.2
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• pp.104-122
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• 2019

In the era of the fourth industrial revolution, maker education is drawing attention as a method of student-led education. At a time when interest in maker education is also growing in technology education, figuring out what stage of concern(SoC) a middle school technology teacher is critical to effective implementation. This study analyzed SoC in maker education by layer sampling among 400 middle school technology teachers using Concerns-based adoption model. SoC was then obtained by measuring the origin using the SoCQ and then presenting it as a SOCQ profile. Gender, training experience with two lower variables were analyzed using t verification, working cities, teaching experience with more than three lower variables were analyzed using one-way ANOVA. Studies showed that SoC in maker education of middle school technology teachers showed the most similar characteristics to that of non-users. The difference in concern depending on gender was that male teachers were more concerned in maker education than female teachers. The difference in concern depending on the working city was that teachers working in the township were more concerned in the maker education than teachers working in the large city, and the difference in concern depending on the teaching career was higher among teachers with middle experience than those with low and high experience. There was also a higher stage of concern in maker education than in teachers without training experience. Therefore, it is necessary to provide middle school technology teachers with an introduction to the maker education and various information, teaching, learning and evaluation data to enhance overall concern and to support the use and evaluation of the maker education in the classroom by providing various teacher training and consulting on the maker education in the future. Further, through further study, we should conduct study that analyzes both Stage of Concern, Level of Use and Innovation Configuration, to put in the effort for effective settlement of maker education.

• Journal of the Korean Institute of Landscape Architecture
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• v.16 no.1
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• pp.27-35
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• 1988

Size characteristics of three widely used landscape trees were analized to establish a methodology of size prediction as time Passes. Tree height, tree width, stem diameter(breast or surface), canopy length and tree age were measured directly and indirectly(by using photograph), and the data were analized by using regression analysis through PC-SAS. The results are summarized as follows : 1. Zelkova serrata MAKINO showed relatively slow growth rate and the tree form was changed as aged. Size predictions were available by using the regression equations listed below : Surface diameter = 0.8293 x AGE Tree height = 0.4109(0.8293 x AGE) - 0.0039(0.7273 x AGE)$^2$Tree width = 0.3240(0.8293 x AGE) - 0.0024(0.1293 x AGE)$^2$Canopy length = 0.1337(0.8293 x AGE) - 0.0020(0.7293 x AGE)$^2$2. Pinus strobus L. showed relatively fast growth rate and the tree form did not change much as aged. Size predictions were available by using the regression equations listed below. Breast diameter = 0.756 x AGE Tree height = 0.7695(0.756 x AGE) - 0.0164(0.75\ulcorner x AGE)$^2$Tree width = 0.4331(0.756 x AGE) - 0.0079(0.75\ulcorner x AGE)$^2$Canopy length = 0.1365(0.756 x AGE) - 0.0032(0.75f x AGE)$^2$ 3. In case of Magnolia denudata DESROUX, tree form was determined relatively earlier than the other two species. Si2e predictions were available by using the regression equations listed below : Surface diameter = 0.88 x AGE Tree height = 0.5412(0.88 x AGE) - 0.0110(0.88 x AGE)$^2$ Tree width = 0.3752(0.88 x AGE) - 7.0061(0.88 x AGE)$^2$Canopy length = 0.1110(0.88 x AGE) - 0.0022(0.88 x AGE)$^2$ This study aimed to find a way to predict size change of landscaping plants. This methodology will be applied to a wide range of landscape plants to provide practical data to landscape designers.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.2
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• pp.77-85
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• 2014

This study was conducted to examine the morphological characteristics of those Azalea Cultivars(hereinafter, Azalea Cultivars) that are mainly used for landscaping in Korea in order to prepare classification criteria. As testing materials, major Azalea Cultivars cultivated in large quantities by its producing companies were collected. Thereafter, the qualitative and quantitative characteristics of the traits of Azalea Cultivars were investigated in the way of characteristic investigation for new cultivars of azalea used by the Korea Seed and Variety Service in order to classify them and prepare the classification criteria. Since cultivar names have not been established for Azalea Cultivars for landscaping thus far, the data were compiled using the names used by cultivating companies. According to the results, Azalea Cultivars cultivated in Suncheon, Jeonnam mainly for landscaping were 10 in number; Beni, Daewang, Three, Zasanhong, Hancheol, Sancheoljuk, Gyeobsancheoljuk, Baekcheoljuk, Akado, and Seok-am. Among them, the cultivars Beni, Daewang, and Three could not be easily distinguished from each other because they are commonly called Yeongsanhong by cultivating companies and the shapes of their leaves and flowers are similar to each other. In particular, the flower color of Beni was 'bright red', that of Daewang was 'vivid purple', and that of Three was 'bright purple'. In addition, Zasanhong and Hancheol were similar to each other in shape the degree of expression of spots on the flowers and the gloss on the front side of the leaves of Hancheol were higher and stronger compared to that of Zasanhong. Sancheoljuk flowered in early April, earlier compared to other Azalea Cultivars. Gyeobsancheoljuk is an elementary species of Sancheoljuk and it had double flowers although all other traits were similar to those of Sancheoljuk. Although Baekcheoljuk was easily distinguished because it had white flowers, its leaves were similar to those of Akado the reason why these two cultivars could not be easily distinguished from each other. The cultivar Akado flowered early May later compared to other Azalea Cultivars and its flowers were relatively large in diameter as with Baekcheoljuk and Sancheoljuk. Finally, the cultivar Seok-am was easily distinguished because it had smaller leaves compared to other cultivars and it flowered late as with the cultivar Akado.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.34 no.3
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• pp.50-66
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• 2016

This study attempts to understand and explain how "Directed Attention Restorative Environment (DARE)" is managed and fostered in "Gang-Hak (講學)" and "Yu-Sik (遊息)" spaces both inside and outside of Oksan Seowon Confucian Academy, Gyeongju. Directed Attention is a pivotal element in human information processing so that its restoration is crucial for effective thinking and learning. According to Kaplan & Kaplan's Attention Restoration Theory, an environment, in order to be restorative, should have four elements: 'Being Away,' 'Extent,' 'Fascination,' and 'Compatibility.' We could confirm OkSan Seowon Confucian Academy has an inner logic that integrates two basically different spacial concepts of "Jangsu" and "Yusik" and thus fosters the Attention Restorative Environment. Particularly, the Four Mountains and Five Platforms (四山五臺) surrounding the premises provides an excellent learning environment, and is in itself educational in terms of the Neo-Confucian epistemology with "Attaining Knowledge by way of Positioning Things (格物致知)" as its principle precept, and of its aesthetics with "Connectedness with Nature" as its central tenet. This study attempts to recapture the value of Korea's cultural heritage concerning the Human/Nature relationship; and it may provide useful insights and practical guidelines/grounds in designing today's schools and campuses, where the young people's needs for the Directed Attention- and Attention Restorative- Servicescapes seem to be greater than ever.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.34 no.3
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• pp.38-49
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• 2016

This study is based on the assumption that the documentations, and poetry form a basis for undertone of the location and original landscape explored by inference and enjoyment aspects; the significance has been inferred by investigating the original location, relocated location, and the original landscape of Imsil Manchwi Pavilion. The results of the attempted research for locational value, and preservation of the original landscape before and after the relocation of Imsil Manchwi Pavilion is as follows. Firstly, Manchwi, meaning evergreen, was made a pseudonym of KimWi. The name reflects an image two evergreen pine trees facing one another. The poetry form presents the eternal fidelity. In addition, considering the symbolic plant and the meaning of evergreen pine trees specified on the pavilion, the name is derived from the fidelity, longevity of the family, vitality and so on. Secondly, Manchwi Pavilion was founded in the location, known as the snakehead form, that represents the vitality. Snake faces the swallow form over the river, therefore, it connotes the wishes for fidelity and prosperity of the family. Manchwi Pavillion is prostrate pheasant form which is suitable for those who look for a hiding place or place for their study. It is noticeable that the location infers and hand down the efforts on succession for prosperity of the family and the study. Thirdly, it is estimated that Manchwi Pavilion was established between 1572 and 1582; and the relocation was conducted in the late 1880s. Fourthly, although eternal fidelity was presented in Manchwi Pavillion with locational language, the Manchwi Pavillion after its relocation next to KimWi's grave implies the tendency of the changed value: the commemoration of the ancestors, and prosperity of the family. Fifthly, after the relocation of the pavilion, the proportion of the rooms with Korean heating system, so-called'Ondol'has been increased for its best use in all seasons. And its veranda for extension and its verse couplet implies that this connote the original meaning and pursuit of the study. Sixthly, the way that the poetry portrays pine trees, pond, plants, valleys, and streams shows the aspect of enjoyment of the landscapes and the meaning of fidelity, pure mind, free and easy life, self-examination, the frailty of human life. Lastly, despite the difference between tenth poetic language of three Sipyoung and Wonwoon Sipyeong, exploring the landscape based on the analysis on the poetry can be a basis on the maintenance and restoration of the original landscape as the inspiration and the meaning show that Wonwoon Sipyeong maintains the aspect of the author enjoying original landscape.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.35 no.1
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• pp.36-47
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• 2017

In this research, sematic comparative study on formative idea and landscape elements composition was made between Soswaewon which was a remote villa garden in Joseon Dynasty and Canglang Pavilion which was built at a time when Neo-confucianism had been created in Song dynasty. From which the summary was resulted as below: Firstly, Soswaewon was fully devoted to Neo-confucianism among Korean remote villa gardens, Canglang-Pavilion was deeply affiliated with Neo-confucianism the deep-rooted thought. Adding a comment, as a richly historied Chinese private garden it was the best preserved even now and the farmost point from now and approximately 500 years advanced than Soswaewon, moreover Sosunheum the builder belonged to gentry society in Song dynasty. Secondly, Both Soswaewon and Canglang-Pavilion were remarkable thank to nature friendly concept which was deeply rooted in the eremitic thought(隱逸思想). Most of all, it might be interpreted the location of Soswaewon lay down in a mountain, as to be swallow hidden(小隱) but that of Canglang-Pavilion lay down in a city, as to be middle hidden(中隱). Thirdly, approaching with comparative study to gardens' factors implicated in symbolization when naming both Soswaewon and Canglang-Pavilion, neo-confucianism in Song dynasty in which diverse thoughts ranging Confucianism and Buddhism and Taoism had formed ensemble and developed was deeply built in Soswaewon, as to be in consistency to nature and to be a basis for comprehending diverse symbolization factors found in Canglang-Pavilion. Fourthly, given that forms or factors of gardens was tangibly came up with thoughts' variation we surely underwent to comparative study. Through which we could know Soswaewon was made by maximizing use of nature but minimizing addition of artificial things. In other words, it was trial of expressing semantic feature of the site in a way blending natural circumstance and liberal one. One of the representatives, Daebongdae in Soswaewon was a site where the owner's idea came up with. Scenary was recreated and nature was represented in interspace of Canglang-Pavilion with the high wall around the border, for which it renounced the world. To the end, it was understood there was the location characteristic of Canglang-Pavilion which let us look down from mountain and take some time for introspection. It might be said that the cultural root was in common between Korea and China, however it was found there were lots of differences in forms and features of gardens. We were able to interpret that social and cultural background were led to gardens' formation in which individual characteristic of two nations were blended, from which difference was resulted.