• The Journal of Korean Academy of Prosthodontics
• /
• v.48 no.3
• /
• pp.189-193
• /
• 2010

Purpose: This study was aimed to investigate the frequency of different classes of partial edentulism and the most frequently used design components of conventional removable partial dentures. Materials and methods: 63 patients who were treated with removable partial denture in Kyungpook National University hospital for 2003-2006 were selected. A total of 76 removable partial denture frameworks were investigated. Kennedy classification was used to identify the class of partial edentulism. Results: Results indicated that Kennedy class I removable partial dentures were the most frequently constructed. Most patients' cases were designed without modification areas. Conclusion: The most common type of direct retainer were the RPI clasp and RPA clasp in both maxilla and mandible. Lingual bar, linguoplate and anterior posterior palatal straps were the more frequently used mandibular and maxillary major connectors respectively. We did not have any case about Kennedy class IV patients.

• Korean Chemical Engineering Research
• /
• v.52 no.2
• /
• pp.214-218
• /
• 2014

In this study, nanoporous $Cu_3(BTC)_2$ membranes were synthesized on macroporous alumina tube supports by solvothermal method. It is very difficult to prepare uniform and crack-free $Cu_3(BTC)_2$ layer on macroporous alumina support by in situ solvothermal method. In this study, continuous and crack-free $Cu_3(BTC)_2$ tubular membranes could be obtained by in situ solvothermal process after surface modification of alumina support. The surface modification was conducted by spraying Cu precursor solution on the alumina support heated at $200^{\circ}C$. The prepared $Cu_3(BTC)_2$ tubular membranes were characterized by XRD, FE-SEM and gas permeation experiments. $H_2$ permeance through $5{\mu}m$ thick $Cu_3(BTC)_2$ tubular membrane was calculated to be $7.8{\times}10^{-7}mol/s{\cdot}m^2{\cdot}Pa$ by single gas permeation test, with the ideal selectivities of $H_2/N_2=11.94$, and $H_2/CO_2=12.82$.

• Journal of the Korean earth science society
• /
• v.32 no.1
• /
• pp.124-139
• /
• 2011

This study was to explore epistemological features presented in texts of exhibit panels in the science museum located in Gyeonggi Province. Out-of-school or daily experiences allow more properly and potentially students to form informative science image, because the understandings of scientific epistemology were constructed tacitly through various experiences over a long period of time. The target for this study was panel texts of exhibits in a science museum as an of out-of-school context. The analytical framework was adopted from epistemological frameworks by Ryder et al. (1999). The research results were explored in the categories of relationship between scientific knowledge claims and the data, the nature of lines of scientific enquiry, and social dimension of science. It revealed that one exhibit might reflect the characteristics of one epistemological position: relating one data to one knowledge claim; generating knowledge claim from scientists' individual interests or from discipline's internal epistemology; scientists working as a community or an institution. Findings suggested that the exhibits of a science museum including panel texts and medium need to reflect the wide ranges of scientific epistemology.

• Journal of The Korean Association For Science Education
• /
• v.38 no.2
• /
• pp.187-202
• /
• 2018

This study posits that a more equitable science education is possible through analyzing the sociocultural mechanisms that operate in the participation and marginalization in science learning process, and therefore aims to review research trends in this area of science education. To do so, the study analyzed 85 articles that adopted a sociocultural approach to science learning identity in major international journals. The review was organized into 1) overall trends such as the number of articles by year, country, learner's sociocultural background, research context and research methods, and 2) a more in-depth analysis of the main research problems and conceptual frameworks along with concrete research examples. The study found that the current research works in this area have contributed to broadening the idea of legitimate learners in science education by considering learners' various sociocultural identities as the positive resource for learning based on the premise that science learning occurs as identity formation through participating communities of practice, and critiquing the culture or discourses that oppress such identity formation. The studies in this area also brought up the equity issue in science education in ways which embrace various learners that had been marginalized in the traditional science class and facilitate their agency. Based on these findings, the study made a case for analyzing various sociocultural mechanisms relating to the participation and marginalization in science learning to realize 'science education for all Koreans' and proposed future research direction.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.26 no.3
• /
• pp.253-264
• /
• 2010

The purpose of this study is to know whether Yttrium-stabilized-tetragonal -zirconia-polycrystal(Y-TZP ceramic) gets enough shear bond strength for clinical uses by applying veneering composite resin through surface treatment on it and finally to compare it with the case of applying veneering porcelain. LavaTM zirconia frameworks(3M ESPE, Seefeld, Germany) were prepared. Group P was manufactured with LavaTM Ceram(3M ESPE, Seefeld, Germany) in cylindrical shape which has 4mm diameter, 5mm height. Group ZSR disposed sandblasting and applied silane, bonding agent and after that indirect composite resin was applied. Group ZRR got tribochemical coating by RocatecTM system(3M ESPE. Seefeld, Germany) and treated silane. Finally Group ZPR took the same treatment and applied LavaTM Ceram in the size of 0.3-0.5mm height. After burning out, sandblasting, HF and silane was applied. And then, indirect composite resin was applied. 1000 cycle thermocycling was performed in $5-55^{\circ}C$ and shear bond strength was measured. There were no significant differences between combining veneering porcelain to Y-TZP ceramic group and combining veneering resin to Y-TZP ceramic group in the aspect of shear bond strength (p>.05).

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.41 no.1
• /
• pp.23-34
• /
• 2004

This paper presents architecture and control method of packet scheduler to guarantee QoS of high quality streaming services in high-speed packet-switched networks. Since streaming services need far more stringent QoS requirements than the typical sort of burst data applications, they should be guaranteed minimum bandwidth and end-to-end delay bound to each flow, regardless of the behavior of other flows. To meet these requirements, a packet scheduler isolate a flow from the undesirable effects of other flows and provides end-to-end delay guarantees for individual flow and divides stringently the available link bandwidth among flows sharing the link. Until now, many vendors are developing traffic management chips running at 10Gbps, but most of chips have drawbacks to support high quality streaming services. In this paper, we investigate the drawbacks of commercial TM chips and traffic characteristic of streaming services and present implementation frameworks of the proposed packet scheduler. Finally, we analyze the simulation results of the proposed scheduler.

• Journal of the Economic Geographical Society of Korea
• /
• v.11 no.4
• /
• pp.509-526
• /
• 2008

This paper aims to examine the evolutionary dynamics of the Korea's footwear industry by adopting evolutionary perspectives. To explain the evolutionary dynamics of an industry, evolutionary perspectives have paid a particular attention to exploring a variety of factors for influencing the evolution of the industry, such as the selection and imitation of the firm, the mechanism of firm's entry and exit, technological characteristics and innovation processes. The majority of existing research tend to explain that the decline of the Korea's footwear industry since 1990 was mostly due to the rapid rising of wage and the structural changes in labor-intensive industries. On the contrary, this paper attempts to explain the decline of the Korea's footwear industry, in terms of the path of selection and imitation, the dominant technological paradigm, regulatory frameworks and the meso trajectory of industry evolution. This paper concludes that the decline of the Korea's footwear industry since 1990 was appeared as a result of the evolutionary selection processes of the firms in order to adapt to changes in the environment of competition and the regime of market selection in the global footwear industry.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.11 no.5
• /
• pp.15-27
• /
• 2016

This paper examined the effects of youth entrepreneurship on entrepreneurial intention. Especially, we considered scholastic performance as a moderator on the relationship between youth entrepreneurship and their entrepreneurial intention. An empirical analysis on 251 students attending their third year of Suncheon High School revealed the following results. First, the youth entrepreneurship(risk taking, innovativeness and proactiveness) significantly positive affected entrepreneurial intention. The result corresponds to what many preceding studies emphasize, implying that when risk taking, which enables perseverance through uncertain situations, increases; innovativeness, which enables breaking away from existing frameworks, increases; and proactiveness, which creates new opportunities through future-oriented behavior, increase, the entrepreneurial intention of teenagers also increases. Second, a review of the interaction effect of scholastic performance discovered evidence that scholastic performance moderates the relationship between proactiveness and entrepreneurial intention of youth toward a negative(-) direction. In other words, proactiveness positively effects on entrepreneurial intention, but higher scholastic performance imply that such positive tendencies become weakened. The results of the present study will be able to provide significant theoretical and practical implications in carrying out follow-up studies on the youth entrepreneurship, which has been, up to now, relatively neglected.

• Composites Research
• /
• v.32 no.6
• /
• pp.355-359
• /
• 2019

The high efficient water splitting system should involve the reduction of high overpotential value, which was enhanced by the electrocatalytic reaction efficiency of catalysts, during the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) reaction, respectively. Among them, transition metal-based compounds (oxides, sulfides, phosphides, and nitrides) are attracting attention as catalyst materials to replace noble metals that are currently commercially available. Herein, we synthesized optimal monodisperse Co₃[Co(CN)₆]₂ PBAs by FESEM, and confirmed crystallinity by XRD and FT-IR, and thermal behavior of PBAs via TG-DTA. Also, we synthesized monodispersed Co₃O₄ nanocubes by calcination of Co₃[Co(CN)₆]₂ PBAs, confirmed the crystallinity by XRD, and proceeded OER measurement. Finally, the synthesized Co₃O₄ nanocubes showed a low overpotential of 312 mV at a current density of 10 mA·cm^-2 with a low Tafel plot (96.6 mV·dec^-1).

• Journal of the Korean earth science society
• /
• v.26 no.6
• /
• pp.511-523
• /
• 2005

The purpose of this study is to analyze the 1st and 2nd Korea Earth Science Olympiad (KESO) items, in order to find informations to enhance item quality. To do this, internal and external item classification frameworks are developed. Item difficulty (P), discrimination index (DI), correlation, and reliability are estimated by using classical test theory. Generalizability is also estimated by applying the generalizability theory. The results of item classification are as follows: (1) ‘Geology’, ‘astronomy’ and ‘data analysis and interpretation’ are dominant in content and inquiry process domain, respectively. Nearly every item has textbook context. (2) There is no difference between the preliminary and final tests in terms of their thinking skills sections. (3) As a whole, the ratio of items with pictures is high in item representation. However, multiple-choice and short answer items are more common in preliminary competition, and essay type items are found more often in final competition. The ratio of simple items is high in middle school section and preliminary competition, but composite items are dominant in high school section and final competition. The findings of item analysis are as follows: (1) In the middle school section, P is low and DI is moderate. But in the high school section, there is a considerable differences between science high schools and other high schools in general. (2) The highest correlation is reported between the scores of meteorology domain and total score in middle school, whereas in high school astronomy domain and total score show the highest correlation. (3) General high school section show the highest Cronbach $\alpha$ and generalizability. (4) General high school section show acceptable generalizability coefficient (> 0.80), but middle and science high school section should increase the number of items to reach acceptable generalizability level.