• Food Science of Animal Resources
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• v.35 no.2
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• pp.164-170
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• 2015

The objective of this study was to evaluated the photoprotective effects of porcine placenta extract (PPE) on ultraviolet B (UVB)-induced oxidative stress in human keratinocytes (HaCaT) to evaluate its functional activities as a skin food ingredient. PPE prepared by subcritical water extraction was termed SPE, and subsequently digested by enzymes to prepare E-SPE. Increased intracellular reactive oxygen species (ROS) levels (192.0%) induced by UVB were decreased by SPE and E-SPE. SPE had more effective ROS scavenging activity than E-SPE treatment. UVB treatment increased expression of tissue inhibitor of metalloproteinase 1 (TIMP-1), and this elevated expression was decreased by E-SPE treatment. High-dose treatment with E-SPE (50 and 100 µg/mL) reduced TIMP-1 expression levels of UVB-C (control) to 33.5 and 34.6%, respectively. In contrast, at low SPE doses (1 and 10 µg/mL), the treatment slightly decreased TIMP- 1 expression levels to 73.3% and 71.3% of UVB-C, respectively. In conclusion, the present study demonstrated the protective effect of SPE and E-SPE against UVB damage in keratinocytes via ROS scavenging, down-regulating MMP-2 expression and up-regulating TIMP- 1 expression. This highlights the potential for SPE as an ingredient in the preparation of functional food against photoaging.

• Journal of Educational Research in Mathematics
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• v.11 no.1
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• pp.157-177
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• 2001

Modern society's technological and economical changes require high-level education that involve critical thinking, problem solving, and communication with others. Thus, today's perspective of mathematics and mathematics learning recognizes a potential symbolic relationship between concrete and abstract mathematics. If the problems engage students' interests and aspiration, mathematical problems can serve as a source of their motivation. In addition, if the problems stimulate students'thinking, mathematical problems can also serve as a source of meaning and understanding. From these perspectives, the purpose of my study is to prove that mathematical modeling tasks can provide opportunities for students to attach meanings to mathematical calculations and procedures, and to manipulate symbols so that they may draw out the meanings out of the conclusion to which the symbolic manipulations lead. The review of related literature regarding mathematical modeling and model are performed as a theoretical study. I especially concentrated on the study results of Freudenthal, Fischbein, Lesh, Disessea, Blum, and Niss's model systems. We also investigate the emphasis of mathematising, the classified method of mathematical modeling, and the cognitive nature of mathematical model. And We investigate the purposes of model construction and the instructive meaning of mathematical modeling. In conclusion, we have presented the methods that promote students' effective model construction ability. First, the teaching and the learning begins with problems that reflect reality. Second, if students face problems that have too much or not enough information, they will construct useful models in the process of justifying important conjecture by attempting diverse models. Lastly, the teachers must understand the modeling cycle of the students and evaluate the effectiveness of the models that the students have constructed from their classroom observations, case study, and interaction between the learner and the teacher.

• Journal of Soil and Groundwater Environment
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• v.17 no.2
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• pp.47-53
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• 2012

In this study, the adsorption of $Cu^{2+}$ and $Cd^{2+}$ from aqueous solution on the biochar derived from used coffee grounds at different pyrolysis temperatures has been investigated as a potential low-cost treatment method for heavy metal-containing waters. Three biochar samples prepared by heating coffee sludge at temperature of $300^{\circ}C$ (B300), $500^{\circ}C$ (B500), and $700^{\circ}C$ (B700) were tested for the adsorption capacity and kinetics of Cd and Cu. Also the influencing factor of heavy metal removal by ion exchange in terms of cation exchange capacity (CEC) of each biochar was measured. Adsorption of Ca and Cu by biochar produced at higher pyrolysis temperature showed higher adsorption capacity but the optimal pyrolysis temperature based on performance and economy was known as $500^{\circ}C$. Sorption of Cu and Cd by biochar followed a Langmuir model at pH 6~6.5, attributing mainly to surface sorption. The biochar was more effective in Cu and Cd sorption than activated carbon (AC), with BC 500 being the most effective, which indicates that sorption of Cd and Cu by coffee sludge biochar is partly influenced by chemical sorption on surface functional group as well as physical sorption.

• Korean Journal of Organic Agriculture
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• v.11 no.3
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• pp.1-19
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• 2003

The operation of a five day workweek seems to be increased continuously, Many city-workers will make good use of their spare time and search after a lot of devices that can seek for the maximum value of leisure utility. The demand of potential customers that want to enjoy weekend in farming villages is coming out greatly. That is, the condition of users that will travel the farming villages is getting better. But the actual states of farming villages are not ready in many parts yet. Therefore we must activate the tourist attraction in farming villages that can be satisfied the city-workers' expectation. And after making the sightseeing environment infrastructure, we must develop the programs intimate with environment, improve the sightseeing agricultural management and consolidate various systems as soon as possible. So in this study, after investigating the demand preference degree of city-workers, I tried to grope an activation plan with the base which will reach. Being more urgent what more, not the simple sightseeing agriculture that the farming experience was the focus of, but it is very important to develop the program of environment sightseeing agriculture. It will lay the stress on playing and education culture which city-workers can enjoy and experience. And with constructing the base facility like a city form, we must develop cheap and various goods and the execution of modernized weekend farms. For this, first the consciousness conversion against the customer management of farmers must precede and the change of government policy and the support polity is important. I hope that this study with the five-day workweek has the chance to contribute in the economic growth of farming villages and efficient use and management of the natural environment resources through the activation of sightseeing agriculture.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.519-525
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• 2006

Advances in information and telecommunication technology increasingly reveal the potential of computer supported education. However, most computer supported learning systems until recently did not pay much attention to different characteristics of individual learners. Intelligent learning environments adaptive to learner's preferences and tasks are desired. Each learner has different preferences and needs, so it is very crucial to provide the different styles of learners with different learning environments that are more preferred and more efficient to them. This paper reports a study of the intelligent learning environment where the learner's preferences are diagnosed using learner models, and then user interfaces are customized in an adaptive manner to accommodate the preferences. In this research, the learning user interfaces were designed based on a learning-style model by Felder & Silverman, so that different learner preferences are revealed through user interactions with the system. Then, a learning style modeling is done from learner behavior patterns using Decision Tree and Neural Network approaches. In this way, an intelligent learning system adaptive to learning styles can be built. Further research efforts are being made to accommodate various other kinds of learner characteristics such as emotion and motivation as well as learning mastery in providing adaptive learning support.

• Journal of the Korean Institute of Gas
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• v.15 no.5
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• pp.7-12
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• 2011

LPG(Liquefied Petroluem Gas) Vehicles in metropolitan area being applied to improve air quality and have been proven effective for the reduction of air pollution. These gas stations are required to safe the storage tank because of possibility of causing huge loss of life and property. While storage tanks above ground have potential risk of explosion if fire breaks out and those under-ground are difficult to inspect due to poor accessibility neither above nor under-ground tank can serve us well. This study used the RPS-TRIZ (Rapidly Problem Solving-Teoriya Resheniya Izobretatelskikh Zadatch) technique and suggested the use of under-ground containment storage tank as a solution for safety issues and safety inspection.

• Nutrition Research and Practice
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• v.10 no.2
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• pp.206-211
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• 2016

BACKGROUND/OBJECTIVES: Obesity, which is a known risk factor for many chronic diseases, has also been associated with vitamin D deficiency. This study explored the relationship between serum 25-hydroxy-vitamin D [25(OH)D] concentrations and adiposity measures in a general Korean population using the most recent, nationally representative survey data. SUBJECTS/METHODS: The study sample consisted of 4,771 Korean adults (${\geq}19years$) who participated in the fifth Korean National Health and Nutrition Examination Surveys. Serum 25(OH)D was determined by radioimmunoassay. Body mass index (BMI), waist circumference (WC) and total body fat content were measured as adiposity measurements. Total body fat content was measured by dual-energy X-ray absorptiometry. RESULTS: The serum 25(OH)D level was significantly higher in men than in women. Serum 25(OH)D concentration was positively correlated with energy intake, and it was negatively correlated with total body fat content (P < 0.0001) and percentage body fat (P < 0.0001) after adjustment for age in both sexes, while was inversely correlated with BMI only in women. In multivariable regression analysis, serum 25(OH)D was inversely associated with the total body fat content after adjustment for age, BMI, education, region, smoking, alcohol consumption, physical activity, and energy intake only in men (P = 0.0047). However, the serum 25(OH)D concentration was not associated with WC or BMI, indicators of adiposity after adjustment for potential risk factors. CONCLUSIONS: Serum 25(OH)D concentration was independently associated with the total body fat content in a general Korean population, but it may be not associated with the indicators for estimating adiposity, such as WC or BMI.

• Journal of Korean Library and Information Science Society
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• v.49 no.1
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• pp.193-214
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• 2018

This study aimed to exploratorily investigate the new roles of libraries in the era of K-MOOC. For this, potential roles were derived and categorized from former researches and practices. And to evaluate the appropriacy of those roles, two expert surveys were conducted. Panel A was comprised of 30 professors who had been running K-MOOC classes and Panel B was comprised of 30 librarians of Universities that had adopted K-MOOC. The result shows that they both agree about distinct roles of library as information provider such as licensing and providing digital contents requested from information users, while technological part, for example, recording video and audio, managing website, and providing open access, was considered inappropriate because those roles were already taken by CTLs. Also, professors agree that information literacy education is required for teachers not just for students as the speed of technological development is too swift and librarians agree that they have to equipped with core competence in preparation for upcoming change by creating added value, establishing closer relationship with various educational and technological institutes, and securing organizational flexibility.

• The Journal of the Korea Contents Association
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• v.14 no.11
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• pp.1019-1029
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• 2014

In recent years, researchers have become increasingly interested in the creation and pedagogical use of English learner corpora. Many studies have shown that learner corpora can not only make a significant contribution to second language acquisition research but also contribute to the construction and evaluation of language tests by advancing our understanding of English learners. So far, however, little attention has been paid to the Korean EFL (English as a foreign language) learners' corpus. The Yonsei English Learner Corpus (YELC 2011) is a specialized, monolingual, and synchronic Korean EFL learner corpus that was developed by Yonsei University from 2011 to 2012. Over 3,000 Korean high school graduates (or equivalents) who were accepted by Yonsei University for their further studies participated in this project. It consists of 6,572 written texts (1,085,828 words) at nine different English proficiency levels. In this paper, we describe its compilation, and more specifically, how we have corpusized from a text archive to a corpus. After introducing the process of corpusization, we report arresting insights into the specific linguistic features that different proficiency levels of Korean learners of English have. This study also discusses the potential use of the YELC 2011 which is now freely available for research purposes.

• Fashion & Textile Research Journal
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• v.19 no.3
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• pp.331-336
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• 2017

Bacteria exist everywhere and continuously come into contact with daily surroundings and humans. Super bacterium methicillin-resistant Staphylococcus aureus, resistant to methicillin, has recently appeared. The morbidity and rate of death associated with super bacteria infection has increased. This study investigated the antibacterial activity of fabrics naturally dyed with Chamaecyparis obtusa leaves extract against methicillin-resistant Staphylococcus aureus. Fabrics were left for 15 min in a natural dyeing solution prepared by extraction from C. obtusa leaves using 11.3% (o.w.f) with a fixed liquor ratio of 1:22 at $40^{\circ}C$. The dyeing process was conducted using three different mordants; subsequently, the K/S value of the dyed fabrics increased in the order of None < Cu < Fe < Al. The color fastness property of the fabrics to washing, dry-cleaning, and rubbing was found to be excellent and ranked in the 4-5 grade. The color fastness to light of natural dyeing is low in most cases and has the problem that the dye color soon becomes bleached. Yet, in most cases cloth dyed with retinispora leaves, the color fastnezz to light was good with a third to fourth grade. Non-mordant fabrics, aluminum mordants, and copper mordants also showed better antibacterial properties (99.9% reduction) against methicillin-resistant Staphylococcus aureus, compared to the control fabrics. The dyed fabrics showed the same antibacterial activity even after three washes. The results highlight the strong potential of fabrics naturally dyed with C. obtusa-extract as a medicinal material with excellent antibacterial function against methicillin-resistant Staphylococcus aureus.