• Journal of Advanced Marine Engineering and Technology
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• v.28 no.5
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• pp.773-781
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• 2004

This research was Performed to raise grade efficiency of Sturtevant type air classifier. to treat powder less than $74\mu\textrm{m}$ particle produced at the crushing process of the dry aggregates manufacturing system or concrete wastes recycling system. The experimental conditions were in the ranges. 0.85 to 5.15 $m^3$/s of primary air flow rate. 0.005 to 0.015 $m^3$/s of secondary air flow rate $30^{\circ}$ to $70^{\circ}$ of auxiliary blades angle. respectively. for 1.7~3.3 kg/min of the powder feed rate. It was found that the grade efficiency of the air classifier was increased as the baffle plate was attached at the expansion region. and the optimal operating conditions of the air flow rates and the blade angle were obtained. The fractional recovery curves from the experiments were well agreement with the theoretical one of Molerus model.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.60-66
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• 2004

Hardness value decreased about 3% for annealed specimens and increased about 60% for one hour aged specimens. But the values of the other specimens aged two hours or more showed almost the same. The yield strength was the highest about 1,800㎫ in 0.06%Nb specimen having twice as much as the base meta1 specimen. Also, the elongation was the highest in 0.03%Nb specimen showing the same as base metal specimen. The higher aging temperature and the longer aging time, the higher fatigue life. On the other hand, the 0.03%Nb specimen showed the highest fatigue life which increased about 12% more than base metal specime. 0.06%Nb specimen aged at 482$^{\circ}C$ for 8 hours simultaneously satisfied the 250 grade strength and 200 grade elongation having the most superior mechanical properties.

• Economic and Environmental Geology
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• v.13 no.4
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• pp.241-246
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• 1980

Some components in uranium-bearing formations which consist mainly of black shale, slate. and low grade coal-bearing formation of Ogcheon Belt were processed statistically in order to find out the geochemical correlations with uranium. Geochemical enrichment of uranium, vanadium and molybdenum in low grade coal-bearing formations and surrounding rocks is remarkable in the studied area. Geochemical correlation coefficient of uranium and molybdenum in the rocks displays about 0.6, and that of uranium and fixed carbon about 0.4. Uranium and vanadium in uranium-bearing low grade coals denote very high correlation with fixed carbon, which is considered to be responsible for enrichment of metallic elements, especially molybdenum. Close geochemical correlation of uranium-molybdenum couple in the rocks can be applied as a competent exploration guide to low grade uranium deposits of this area.

• Journal of Ginseng Research
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• v.17 no.3
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• pp.219-223
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• 1993

Assessment of root weight grade system for the numeral definition in Korea ginseng was tried by investigation of 13 boxes of the 15-root-grade of 4-year-old white ginseng as a model. In this case satisfaction to theoretical value was 58% in root weight and 50% in root number. The coefficient of variation (CV) was high (35%) for individual root weight in package. The CV of tap root weight 1 among package is low (7.1%) even though there was no significant correlation between tap root weight : and lateral root weight among roots. The mean percentage of tap root to root weight in each package ranged 61 to 74% with CV range of 16.5 to 33.2%. The CV was not much different between 1st and 2nd lateral root weight and the means was above 60%. Strict practice of numeral definition of root weight grade system will be prerequisite for chemical standardization of Korea ginseng.

• Journal of information and communication convergence engineering
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• v.2 no.2
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• pp.97-101
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• 2004

This paper is about the use of existing evaluation methods, which evaluate learning determined by the score of an exam, which is either a multiple-choice type or single choice type question. These scores don't show the objective evaluations that cause some negative opinions about the scores. In this paper, we propose that the evaluation of the methods of self-directed learning use the triangle-type function of the fuzzy theory so that the learner can objectively evaluate their own learning ability. The proposed method classifies the result of learning into three fuzzy grades to calculate membership, and evaluate the result of an exam according to the final fuzzy grade degree as applied to the fuzzy grade sheets.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2004.11a
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• pp.212-220
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• 2004

In this work the Dynamic Matrix Control method is applied to control the grade change operations in paper mills. Paper process trained by neural network regards a real-plant. The model obtained with operation data is used to achieve DMC. Results of simulations for DMC control of grade change operations are compared with plant operation data response. From the comparison, we can see that the proposed DMC method exhibits faster response for the grade change of paper and achieves stable steady-state.

• Journal of Fisheries and Marine Sciences Education
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• v.26 no.6
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• pp.1392-1401
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• 2014

This study was conducted to understand elementary school from third to sixth grade students' conceptions of evaporation and condensation to classified by grade and examples of questionnaires. For this purpose, 1606 students from 3rd grade to 6th grade were involved. They had conceptions of evaporation and condensation questionnaire. The results of this study were as the following: Firstly, students have to know about the basic conceptions to understand conceptions of evaporation and condensation. Secondly, it would appear that these ideas can sometimes be influenced in unintended ways and be not easily changed by science teaching. Thirdly, it would appear that they understood conceptions of evaporation better than that of condensation.

• East Asian mathematical journal
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• v.39 no.2
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• pp.199-227
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• 2023

The Korean government initiated an educational policy regulating academic acceleration in schools (e.g., regulating teaching or assessing above-grade-level content) in order to normalize public education and prevent the growth of private tutoring. To analyze whether the policy is achieving its intended goals, this study examined how high school mathematics teachers responded to the policy. The findings indicate four distinct teacher responses: the teachers would teach above-grade-level lessons in classes, but not assess them on a test; the teachers sought academic acceleration to prevent excessive private tutoring, although the policymakers thought that teachers' academic acceleration results in an excessive demand for private tutoring; the teachers were willing to teach above-grade-level content for students, but they were reluctant to teach below-grade-level content due to the time constraints; and the teachers recognized that the policy limited their curricular autonomy, even though it was intended to ensure their autonomy. Implications for mathematics teacher educators and policymakers are discussed.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.6 no.7
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• pp.151-158
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• 2016

The 21st century is an era of knowledge innovation. Under the era background of knowledge explosion and information explosion, the competition among countries is ultimately talent competition. High-end talents are the core element of national competitiveness. Today, with the rapid development of science and technology and knowledge changing with each passing day, the cultivation of students' creativity is the requirement of social development and national progress. This paper makes a comparison between the creativity of business school students in China and Korea with questionnaire survey. Empirical study and comparative study with university students by grade in China and Korea are performed. The test results indicates that there are differences between Korean and Chinese students. Also, university students' creativity are different by grade. This study finds internal reasons for creativity differences and puts forward counter measures and methods for improving students'creativity.

• The Journal of the Korea Contents Association
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• v.22 no.6
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• pp.116-124
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• 2022

The purpose of this study is to examine the vertical and horizontal continuity between grades and publishers, respectively, by analyzing the readability of reading passages included in English textbooks for 5th and 6th grades of elementary school. In order to do so, a corpus was constructed with the reading passages contained in 10 textbooks, and the reading passages in each textbook were analyzed through Coh-Metrix. Also, it was examined whether there was a statistically significant difference between grades and publishers in readability through one-way ANOVA. The results are as follows. First, as a result of analyzing the difference in readability between publishers within the same grade, there was a statistically significant difference between fifth-grade textbooks in the L2 readability index. Second, as a result of analyzing the vertical continuity between grades within the publisher, the difficulty of textbook A was higher in grade 6 than grade 5 based on FRE and FKGL, which showed a statistically significant difference. On the other hand, when L2 readability was used as the standard, the difficulty of textbook B was lower in 6th grade than in 5th grade. This result seems to be because FRE and FKGL calculate readability based on sentence and word length, whereas L2 readability is based on content word overlap, word frequency, and syntactic similarity of sentences.