• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.577-580
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• 2005

This paper reports the high sensitivity actuator for flexible disk. The air stabilized flexible optical disk has very small axial runout. Therefore, It is proper to develop an actuator which has high sensitivity in tracking direction rather than in focusing direction. In order to maximize driving force in radial direction, we present an efficient design of magnetic circuit with simple multi-polarized magnets and auxiliary magnets. Designed magnetic circuit has big force in tracking direction. And we shift 2$^{nd}$ resonance frequency of moving parts Into high frequency band, not causing increase of mass and discord between force and mass centers to secure high sensitivities and sufficient control bandwidth. Finally, experimental results show that designed actuator has superior sensitivity in tracking direction.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.3
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• pp.433-442
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• 2023

The purpose of this study is to reveal the Korean learners' usage pattern of '의', the genitive particle, according to semantic classification, so that it can be referred to in determining the contents and methods of related education. The method of this study adopts a quantitative analysis using learners corpus established by National Institute of Korean Language. As a result of the analysis, as proficiency increases, the overall frequency of '의' increases and the number of meaning senses used increases. However, the frequency of errors also increases with it. As for the usage pattern of each sense, the meaning of 'ownership, belonging' is the most frequent, and followed by 'acting entity', 'kinship, social relations', and 'relationship(area)'. In conclusion, the meanings of 'acting subjects' and 'relationships(area) need to be supplemented with explicit education. Other meanings need to be discussed, and decisions should be made in consideration of learning purpose and proficiency.

• Asia Pacific Journal of Corpus Research
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• v.4 no.2
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• pp.57-74
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• 2023

Having a firm grasp of technical terms is essential for learners of Japanese for Specific Purposes (JSP). This research aims to analyze Japanese nursing care vocabulary based on objective corpus-based frequency and subjectively rated word familiarity. For this purpose, we constructed a text corpus centered on the National Examination for Certified Care Workers to extract nursing care keywords. The Log-Likelihood Ratio (LLR) was used as the statistical criterion for keyword identification, giving a list of 300 keywords as target words for a further word recognition survey. The survey involved 115 participants of whom 51 were certified care workers (CW group) and 64 were individuals from the general public (GP group). These participants rated the familiarity of the target keywords through crowdsourcing. Given the limited sample size, Bayesian linear mixed models were utilized to determine word familiarity rates. Our study conducted a comparative analysis of word familiarity between the CW group and the GP group, revealing key terms that are crucial for professionals but potentially unfamiliar to the general public. By focusing on these terms, instructors can bridge the knowledge gap more efficiently.

• Journal of Korean Medical classics
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• v.31 no.2
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• pp.71-82
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• 2018

Objectives : The purpose of this study is to compare the similarities among Donguibogam(DO), Uihagibmun(UI), and Gyeongagjeonseo(GY) in order to examine whether the medical thoughts embedded in the texts can be compared in a quantitative way. Methods : Under an empirical assumption that medical thoughts can be reduced to the frequency of major key words within the text, we selected the fourteen words of the four categories that are commonly used to describe physiology and pathology in Korean medicine as key words. And the frequency of these key words was measured and compared with each other in the three important medical texts in Korea. Results : As a result of quantitative analysis based on ${\chi}^2$ statistic, the key words in the books were distributed most heterogeneously in DO and distributed most homogeneously in UI. In comparison of the similarity analyzed by the same method, DO and UI were significantly more similar than those of DO and UI. The results of the word frequency pattern and the similarities of the book contents(CBDF) show that DO is influenced by UI, and the differences between standardized residuals and homogeneity tells us that internal context of both books are constructed differently. Conclusions : These results support the results of traditional research by experts. With the above, we were able to confirm that medical thoughts can be reduced to the frequency of major key words within the text, and compared through the frequency of such key words.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.5 no.3
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• pp.76-85
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• 2024

The purpose of this study is to propose a new method of analysis focusing on interconnections between species rather than traditional biodiversity analysis, which represents ecosystems in terms of species and individual counts such as species diversity and species richness. This new approach aims to enhance our understanding of ecosystem networks. Utilizing data from the 4th National Natural Environment Survey (2014-2018), the following eight taxonomic groups were targeted for our study: herbaceous plants, woody plants, butterflies, Passeriformes birds, mammals, reptiles & amphibians, freshwater fishes, and benthonic macroinvertebrates. A co-occurrence frequency analysis was conducted using nationwide data collected over five years. As a result, in all eight taxonomic groups, the degree value represented by a linear regression trend line showed a slope of 0.8 and the weighted degree value showed an exponential nonlinear curve trend line with a coefficient of determination (R²) exceeding 0.95. The average value of the clustering coefficient was also around 0.8, reminiscent of well-known social phenomena. Creating a combination set from the species list grouped by temporal information such as survey date and spatial information such as coordinates or grids is an easy approach to discern species distributed regionally and locally. Particularly, grouping by species or taxonomic groups to produce data such as co-occurrence frequency between survey points could allow us to discover spatial similarities based on species present. This analysis could overcome limitations of species data. Since there are no restrictions on time or space, data collected over a short period in a small area and long-term national-scale data can be analyzed through appropriate grouping. The co-occurrence frequency analysis enables us to measure how many species are associated with a single species and the frequency of associations among each species, which will greatly help us understand ecosystems that seem too complex to comprehend. Such connectivity data and graphs generated by the co-occurrence frequency analysis of species are expected to provide a wealth of information and insights not only to researchers, but also to those who observe, manage, and live within ecosystems.

• English Language & Literature Teaching
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• v.18 no.1
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• pp.197-216
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• 2012

This study examines spoken interlanguage of Korean learners of English, focusing on the distribution of modal verbs and devices of epistemic modality. (Semi-) spontaneous speech data were collected from four students participating in a self-organized study group for seven months, which produced a corpus of about 55,000 words. The data analysis reveals the following: 1) The frequency of the modal verbs produced by the learners was lower than that of native speakers; 1.99 vs. 2.32 tokens per 100 words. The range of the modal verbs used by the learners was also very limited, with over-reliance on can (43%). 2) The grammatical categories of the devices marking epistemic modality were in the order of adverbs, lexical verbs, and modal verbs, with a high frequency of a few items in each category. 3) Lexical items conveying certainty and modals of obligation were preferred over markers of weaker commitment, resulting in speech characterized by firmer assertions and a more authoritative tone, a potential cause for pragmatic failure. 4) A weak developmental change was observed in the frequency of modal verbs, but not in their functions over the seven month period of data collection. L1 influence, L2 proficiency, mode of communication, and instruction effects are discussed as possible variables involved in the distribution patterns observed.

• Journal of Korean Elementary Science Education
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• v.33 no.1
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• pp.1-20
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• 2014

This study aimed to find out the current conditions and the characteristics of elementary students' science-related engagement in informal education setting. For this, we conducted a survey targeting 645 $6^{th}$ grader elementary students of three elementary school in Seoul. The results were described as following aspects: first, the place, the engagement frequency, and companies of students' science-related activity in informal setting, second, the characteristics of engagement based on homogeneity analysis. Based on these results, we suggested several ways to encourage students' science-related engagement in informal education setting.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.26 no.1
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• pp.1-10
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• 2016

Objectives: The aim of this study is to review the results of exposure to chemicals and to extremely low frequency(ELF) magnetic fields generated in wafer fabrication operations in the semiconductor industry. Methods: Exposure assessment studies of silicon wafer fab operations in the semiconductor industry were collected through an extensive literature review of articles reported until the end of 2015. The key words used in the literature search were "semiconductor industry", "wafer fab", "silicon wafer", and "clean room," both singly and in combination. Literature reporting on airborne chemicals and extremely low frequency(ELF) magnetic fields were collected and reviewed. Results and Conclusions: Major airborne hazardous agents assessed were several organic solvents and ethylene glycol ethers from Photolithography, arsenic from ion implantation and extremely low frequency magnetic fields from the overall fabrication processes. Most exposures to chemicals reported were found to be far below permissible exposure limits(PEL) (10% < PEL). Most of these results were from operators who handled processes in a well-controlled environment. In conclusion, we found a lack of results on exposure to hazardous agents, including chemicals and radiation, which are insufficient for use in the estimation of past exposure. The results we reviewed should be applied with great caution to associate chronic health effects.

• Journal of the East Asian Society of Dietary Life
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• v.26 no.6
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• pp.517-530
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• 2016

This research was conducted on Seoul region elementary, middle, and high school nutritionists to analyze execution conditions of HACCP control standards, focusing on PHF and CCP 3~CCP 7, in order to determine more efficient methods for school meals' sanitation system settlement. All surveys were distributed and collected via email. A total of 305 survey papers were collected, and 300 school results were analyzed. The following percentage of nutritionists perceived the following foods as potentially hazardous foods(PHF): raw or cooked animal foods (94.7%), blossomed seed products (93.7%), packed pickled radish (36.7%), unopened mayonnaise (30.2%), and unopened snails & corn cans 54.8%. Exactly 51.2% of nutritionists believed that foods were properly supplied via CCP 3's food quality standard. Exactly 33.9% of nutritionists answered that they had never corrected the digital thermometer since there were no issues with the CCP 4's digital thermometer correction frequency level. As for CCP 5's chroline disinfection of green vegetables, 57.1% of nutritionists answered that vegetables were slightly softened while 36.2% said there were no changes at all. According to the nutritionists, the most difficult execution level of CCP levels (excluding CCP 3, CCP 4) was CCP 7 (37.1%), CCP 6 (16.4%), and CCP 2 (16.4%). For the above results, proper training/education must be enforced so that nutritionists can have a clear notion of the PHF. A solution must be developed enhancing the execution of CCP 4's digital thermometer correction frequency level. For CP 5's chroline disinfection of green vegetables, food characteristics must be considered to suggest an appropriate number and method of cleansing. Furthermore, cooking employees are needed that properly use and manage cooling & heating equipments to maintain heated foods above $57^{\circ}C$ under the CCP 7 standard.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.195-201
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• 2006

The wave load and its influence on the response of offshore structure have been well investigated through the statistical approach based on the linear theory. The linear approach has a limitation to apply the extreme condition such as freak wave, which corresponds to extreme value of wave spectrum. The main topic of present study is to develop an efficient numerical method to predict wave load induced by extreme wave. As a numerical method, finite element method based on variational principle is adopted. The frequency-focusing method is applied to generate the extreme wave in the numerical wave tank. The wave load on the bottom mounted vertical cylinder is investigated. The hydroelastic response of the vertical cylinder is also investigated so as to compare the wave loads with the rigid body case in the extreme wave condition.