• Analytical Science and Technology
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• v.27 no.6
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• pp.357-363
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• 2014

Isoprene is a one of the biogenic volatile organic compounds (BVOCs) and it is known as a source of the tropospheric ozone and formaldehyde. In addition, isoprene is a trace component of the exhaled breath and it is a potential biomarker for the diagnosis of diseases such as lung cancer. In these regards, isoprene gas standards are required for the accurate measurement of isoprene in air samples. To establish a standard for isoprene gas, gravimetric preparation and characterization of primary gas standards were studied. The primary gas standards were produced independently in 4 aluminum cylinders and concentrations were examined by GC-FID. As a result, the uncertainty of the gravimetric preparations including purity of the raw material was 0.01% and reproducibility of the preparation of independent 4 cylinders was 0.08%. The primary gas standards for isoprene showed 14 months of long-term stability. The relative expended uncertainty of 2.8% (95% of confidence level, k=1.96) was assigned to the certified value of 10 ${\mu}mol$/mol level of isoprene based on the quantitative evaluation of the purity, weighing, reproducibility, adsorption and long-term stability.

• Journal of Dental Rehabilitation and Applied Science
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• v.29 no.3
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• pp.272-279
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• 2013

The concept of implant stability was basically originated from the relative condition of bone-implant interface and has some meanings for evaluation of that interface. In addtion, it has been used for the investigation of initial bone healing process after fixture installation because a degree of micromotion around interface can affect unfavorable clinical results. The purpose of this study is to investigate the mode of initial bone healing from fixture installation through prospective trial. Thirty fixtures were consecutively installed in mandibles of 26 patients with single tooth loss area and then healing abutment were secured for one-stage surgery meothod. Resonance frequency analysis was performed with one week interval during 12 weeks and periapical radiographs were taken at each month. Although marginal bone level change was not shown through observation period (P>0.05), statistical difference of implant stability was shown through 4 and 6 week (P<0.05) and was not shown after 6 week (P>0.05) according to the bone quality. Initial bone healing process is a successive process of bone resorption and favorable bone healing result might be postulated at 4 week interval after installation through RFA.

• The Journal of the Korea Contents Association
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• v.20 no.3
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• pp.298-308
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• 2020

This study was designed to verify reliability and feasibility by analyzing elderly drivers' ability test tools for older drivers aged 65 or older, which were improved in 2018 and are currently being conducted by the Korea Highway Traffic Authority. Only those aged 65 or older who voluntarily applied to the elderly driving ability evaluation system implemented by the Seoul branch of the Korea Highway Traffic Authority. The research was conducted for about 50 days until Aug. 31, 2018, starting with the registration and inspection of the first study subjects. The analysis performed a correlation analysis with existing tools and cognitive testing tools (MMSE_K) to determine their feasibility and reliability as an improved tool in 2018. As a result, the first, the speed distance, time-space memory, and dispersionism of each sub-component of the old version showed statistically significant static correlation with the sub-factor of the current version. Persistence, on the other hand, was not statistically significant to the current version. The limitations of this study were as follows. Most of the people in the study were highly educated and residents in the metropolitan area. Therefore, it is likely that the results of MSE_K, which checks cognitive and judgment skills, have been upgraded. Also, cognitive tools that are measured by computers are likely to have real measurement errors for generations who are not familiar with computers. Therefore, it is expected that improvement and development of tools for improving the limit points at the site and assessing actual operation capability will be required.

• Journal of the Korean Geotechnical Society
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• v.27 no.7
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• pp.47-57
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• 2011

The p-y curve has been used to design pile foundations subjected to lateral loading. Although the p-y curve has a large influence on the pile lateral behavior, p-y curves have not been clearly suggested. In this study, the p-y curve of clay was evaluated for drilled shafts in marine deposits by using 3-dimensional numerical analyses. First, the optimization study was performed to properly determine boundary extent, mesh size, and interface stiffness. The numerical modeling in the study was verified by comparing the calculated and the pile loading test results. Then, the p-y curves of single and group piles were evaluated from the parametric study. The selected parameters were pile diameter, pile Young's modulus and pile head fixed condition for a single pile, and pile spacing for group piles. Finally, the p-multiplier was evaluated by comparing the p-y curves of a single pile and group piles. As a result, the p-multiplier at pile spacing of 3D was 0.83, 0.67 and 0.78 for the front, middle, and back row piles, respectively, and showed values similar to those of O'Neill and Reese (1999). For the pile group with pile spacing larger than 60, the group effect can be ignorable.

• Informatization Policy
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• v.21 no.2
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• pp.89-110
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• 2014

As a travel demand management and environmental policy, the government actively promotes alternative work arrangements such as telecommuting. Against this backdrop, several empirical studies, which aim to verify the benefits of telecommuting, have been recently conducted. Little consensus, however, exists with respect to the defining, measuring, and forecasting telecommuting, although these are fundamental basis of policy evaluation and academic research. As a fundamental research for analyzing telecommuting impacts, this paper reviews various definitions regarding telecommuting, examines telecommuting penetration and level of telecommuting through review of available survey data in Korea, and forecasts future penetration. The result suggests that current home-based telecommuting penetration and level of telecommuting is approximately 0.5 to 1.1% and 0.2 to 0.5%, respectively, and is approximately 0.2% and 0.1%, respectively, for the center-based telecommuting. In addition, shift-share analysis shows that home-based telecommuting penetration in the Seoul Metropolitan Area in 2020 will be 1.3%, not much different with the current value. Consequently, current telecommuting penetration is much lower than the value that is fed to us by the media (10~20%), and the future prospect is also much lower than the goal of government (30~45%); thus, we can conclude that government's goal of telecommuting promotion is difficult to meet if active encouragement policy will not be introduced.

• Journal of Korea Game Society
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• v.11 no.5
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• pp.43-52
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• 2011

This study assumed the competitive structure based on genre classification for Korean online game market, and carried out the analysis on the degree and characteristics of the competition that appear differently in each sub market classified according to the genre. Analysis result can be summarized as follows. (1) In the view of the total play time, the proportions of the online games in each genre were appeared in the order of "RPG > FPS/RTS > Sports > Arcade/Poker > Go-stop > Board/Racing". (2) In the view of the shares in the play time, the degree of competition between games in the sub market structure of the online games according to the genre was found in the order of "RTS > Racing > FPS/Sports > Go-stop > Poker > Arcade/Board > RPG". The evaluation and interpretation of the high and low of the competition degree are as follows. As the degree of competition is higher, (RTS > Racing > ${\cdots}$) the royalty and the ratio of reusing of the users for the game is lower, and on the other hand, the tendency of replacing and using appeared higher, so the market entry barrier for a new game can be evaluated to be low. Reversely, as the degree of competition is lower, (${\cdots}$ > Arcade/Board > RPG) the royalty and the ratio of reusing of the users for the game is higher, and on the other hand, the tendency of replacing and using appeared lower, so the market entry barrier for a new game can be evaluated to be high.

• Korean journal of food and cookery science
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• v.19 no.4
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• pp.454-462
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• 2003

Recently, the HACCP(Hazard Analysis Critical Control Point) system has been emphasized in food processing industries throughout the world. However, the system has, as yet, not been applied very well to domestic food industries. Due to the increase in the consumption of bakery products, more studies are required on the application of HACCP to establish the system in small-scale bakeries. This study was designed to provide basic data for setting management standards for HACCP, based on microbiological hazard evaluations of bakery products. Red bean paste filled breads, custard cream filled breads and cakes covered with fresh whipping cream were collected, and microbiological evaluations conducted on the raw materials, the manufacturing processes and potential hazards. The result showed the presence of coliforms in fresh cream of cakes and the soybean paste of soybean paste breads at levels as high as 105 CFU/g on the hazard analysis of the raw materials. Moreover, the general levels of bacteria and coliforms were over those of the standards during the intermediate fermentation and molding processes. Furthermore, high levels of coliforms were detected on the hands of the salesmen and bakers themselves. This suggests that the CCPs (Critical Control Points), such as fresh cream and red bean paste manufacturing process desperately require better management. There is also a requirement for education relating to personal hygiene for the production of hygienic bakery products and for the publics health.

• Journal of vocational education research
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• v.36 no.4
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• pp.41-56
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• 2017

The purpose of this study is to analyze the level of current difference of education needs for instructional competency of lifelong education instructor and the level of importance of lifelong education for drawing priority. Through the literature review, this is divided the lifelong education instructor's competencies such as planning, implementation, management and support and analyzed the current level and importance with 35 items through t-test analysis. The priority for education needs is applied to Borich and the Locus for Focus model simultaneously. According to result for study, the largest item of competency for lifelong education instructor is verified with the current level and importance for building of social networking and managing competency. The top priority item of education needs for instructional competency of lifelong education instructor is located in the first quadrant of model and the Locus for Focus model, according to priority in needs for Borich and was showed in program competency. The second items in priority were derived by learning resources, information gathering, competency for focus development, equitable evaluation for student, competency for building team work. Therefore, these competencies are considered as factors for priority of lifelong instructor and will be developed in personal and organizational development.

• Smart Media Journal
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• v.9 no.4
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• pp.144-151
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• 2020

In a mobile environment, communication takes place via SMS text messages. Vocabularies used in SMS texts can be expected to use vocabularies of different classes from those used in general Korean literary style sentence. For example, in the case of a typical literary style, the sentence is correctly initiated or terminated and the sentence is well constructed, while SMS text corpus often replaces the component with an omission and a brief representation. To analyze these vocabulary usage characteristics, the existing colloquial style corpus and the literary style corpus are used. The experiment compares and analyzes the vocabulary use characteristics of the colloquial corpus SMS text corpus and the Naver Sentiment Movie Corpus, and the written Korean written corpus. For the comparison and analysis of vocabulary for each corpus, the part of speech tag adjective (VA) was used as a standard, and a distinctive collexeme analysis method was used to measure collostructural strength. As a result, it was confirmed that adjectives related to emotional expression such as'good-','sorry-', and'joy-' were preferred in the SMS text corpus, while adjectives related to evaluation expressions were preferred in the Naver Sentiment Movie Corpus. The word embedding was used to automatically construct a sentiment lexicon based on the extracted adjectives with high collostructural strength, and a total of 343,603 sentiment representations were automatically built.

• The Journal of the Korea Contents Association
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• v.21 no.4
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• pp.50-59
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• 2021

To understand the research trends of English education in Korea for the last 20 years from 2000 to 2019, 12 major academic journals in Korea in the field of English education were selected, and bibliographic information of 7,329 articles published in these journals were collected and analyzed. The total number of articles increased from the 2000s to the first half of the 2010s, but decreased somewhat in the late 2010s and the number of publications by journal has become similar. These results show that the overall influence of English education journals has decreased and then leveled in terms of quantity. Next, 34 topics were extracted by applying latent Dirichlet allocation (LDA) topic modeling using the English abstract of the articles. Teacher, word, culture/media, and grammar appeared as topics that were highly studied. Topics such as word, vocabulary, and testing and evaluation appeared through unique keywords, and various topics related to learner factors emerged, becoming topics of interest in English education research. Then, topics were analyzed to determine which ones were rising or falling in frequency. As a result of this analysis, qualitative research, vocabulary, learner factor, and testing were found to be rising topics, while falling topics included CALL, language, teaching, and grammar. This change in research topics shows that research interests in the field of English education are shifting from static research topics to data-driven and dynamic research topics.