• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.3
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• pp.406-411
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• 2008

In this paper, we introduce the concept of fuzzy (r, s)-pre-semicontinuous mappings on intuitionistic fuzzy topological spaces in Sostak's sense. The concepts of fuzzy (r, s)-pre-semineighborhood and fuzzy (r, s)-quasi-pre-semineighborhood are given. The characterizations for the fuzzy (r, s)-pre-semicontinuous mappings are obtained. Also, we introduce the notions of fuzzy (r, s)-pre-semiopen and fuzzy (r, s)-pre-semiclosed mappings, and then we investigate some of their characteristic properties.

• Journal of Satellite, Information and Communications
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• v.6 no.1
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• pp.86-96
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• 2011

In this paper we propose a Pre-rake system applied with a frequency domain equalizer in TDD/CDMA multi-code transmission. The Pre-rake system has been well known technique in TDD/CDMA to make a receiver simple. However, it still has residual losses of path diversity and signal to noise ratio (SNR). However, gathering all the residual paths demands an additional hardware such as a rake combiner at the receiver. For the reason Pre/Post-rake system has already been proposed at up/downlink correlated channel conditionunder the assumption of noisier channel. There is a trade-off between the first purpose of Pre-rake that makes hardware simple at the receiver and the performance improvement. From the point the frequency domain equalizer (FDE) can be considered in Pre/Post-rake to supply the receiver with the flexible equalizing methods with rather reduced complexity compared with time domain rake combiner or equalizers. Pre-rake itself increases the number of multipath, which results from the convolution of Pre-rake filter and wireless channel, and FDE must be well matched to Pre/Post-rake, while it considers the relationship of hardware complexity and the performance. In this paper, the Pre-rake/Post-FDE system is introduced at TDD/CDMA multi-code transmission. In addition, the cyclic prefix reduction method in the proposed system is introduced, and the theoretical analysis to the proposed system is given by assuming Gaussian approximation, and finally the numerical simulation results are provided.

• Journal of Korean Elementary Science Education
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• v.33 no.4
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• pp.736-750
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• 2014

The purposes of this study were to investigate concepts of Korean and American elementary school pre-service teachers on combustion, and to compare the concepts of Korean pre-service teachers with those of American pre-service teachers. For this study, concept test on combustion was administered to 23 Korean and 18 American elementary school pre-service teachers. The test composed of 6 items: 'Definition of combustion', 'The reason why a candle in a glass bottle is blown out when the bottle was closed', 'The change of gases in the bottle when a candle burns in it', 'The combustion products of a candle', 'The combustion products of steel wool', and 'The combustion products of a substance'. The results showed that the rates of elementary school pre-service teachers who had scientific concepts on combustion were very low in both Korean and American pre-service teachers' groups, although they were a little different from items. However the rates of pre-service teachers who had partial concepts and misconceptions on combustion were high in two groups. The levels of Korean elementary school pre-service teachers' concepts were a little higher than those of American elementary school pre-service teachers' concepts. The contents and activities on combustion which are in Korean and American science textbooks seem to affect building up their concepts on combustion.

• Korean journal of food and cookery science
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• v.8 no.2
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• pp.123-135
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• 1992

Time and temperature conditions, and microbiological qualities of six categories of menu items were assessed according to the process of food product Row in a 500 bed general hospital. The Harzard Analysis Critical Control Point (HACCP) system was applied to determine harzards, to assess their severity and risks, and to identity CCPs and memos for monitoring mem. The Critical Control Points identified for each category of menu items were: Meat Soup (Kyung Sang Do Gogi Guk): Pre-preparation, holding after pre-preration, and holding after cooking; Pot Stewed Stuffed Cabbage (Soe Yangbaechu Mali Chim): pre-preparation, holding after Pre-preparation, stuffing, cooking and holding after cooking; Boned Pork Sour Salad (Doeji Suyuk Muchim): Pre-preparation, holding after pre-preparation, and post-preparation after cooking; Sauteed Pork Ball (Jeyuk Wanja Jon): pre-preparation, holding after pre-preparation, shaping, and holding after cooking; Stir-fried Fragrant Mushroom (Pyogo Bosot Bokkum): basic ingredients, Pre-preparation, holding after pre-preparation, and holding after cooking; and Fried Corn with Vegetables (Oksusu Yachae Tuigim): pre-preparation, holding after pre-preparation, mixing, and holding after cooking.

• Geomechanics and Engineering
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• v.32 no.3
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• pp.321-333
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• 2023

Rock masses often contain natural fractures of varying sizes, and the size of the natural fractures may affect the propagation of hydraulic fractures. We conduct a series of triaxial hydraulic fracturing tests to investigate the effect of the pre-existing fracture size a on hydraulic fracture propagation. Experimental results show that the pre-existing fracture size impacts hydraulic fracture propagation. As the pre-existing fracture size increases, the hydraulic fracture propagates towards the pre-existing fracture tips, evidenced by the decreased distance between the final hydraulic fracture and the pre-existing fracture tips. Furthermore, the attracting effect of pre-existing fracture tips increases when the distance between the wellbore and the pre-existing fracture is short (L/D=2 or 4 in this study). With increased distance between the wellbore and the pre-existing fracture (L/D=6 in this study), the hydraulic fracture propagates to the middle of the pre-existing fracture rather than the tips, as the attracting effect of the pre-existing fracture diminishes.

• Culinary science and hospitality research
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• v.23 no.8
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• pp.98-105
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• 2017

The purpose of this study was to investigate changes in physicochemical properties of apples pre-treated differently with salt and sugar for apple Jangachi. When salt was used, moisture content was decreased by 28.41% to 57.67% at 24 hours and maintained an average 56.92% after 24 hours. However, when sugar was used, moisture content decreased steadily to 41.14% (60h). The pH of the apple pre-treated with salt decreased from pH 4.42 to pH 3.63 at 12 hours. However, in the case of apples pre-treated with sugar, pH decreased from pH 4.52 to pH 4.19 after 48 hours, but was not statistically significant. Conversely, total acidity of apple pre-treated with salt increased from 11.46% to 0.35% during 72 hours. But total acidity of apple pre-treated with sugar decreased to 0.11% at 24 hours and maintained. Sugar content of apple pre-treated with salt increased to 33.1% at 12 hours and maintained. Conversely, in case of sugar pre-treatment, sugar content of apple pre-treated with sugar increased steadily to 45.12% at 72 hours. Salinity of apple pre-treated with salt increased sharply to 15.74% during 24 hours. Lightness ($L^*$) of apple pre-treated sugar was not different from the control group. But apple pre-treated salt decreased slightly. Yellowness ($b^*$) was higher than the control group regardless of pre-treatment group. Sensory evaluation revealed that sugar pre-treatment apples were highly evaluated for flavor, taste, chewiness and overall acceptance.

• Journal of Korean Elementary Science Education
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• v.36 no.3
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• pp.219-226
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• 2017

In this study, the reliability and validity of the retrospective pre-post test were analyzed in order to solve the problem of traditional pre-post test including response shift bias. Samples of the study were 162 elementary school students who are studying at the S university gifted education center in Seoul. Before completion of the field trip, we conducted pre test of science-related attitudes. After completion of the field trip, respondents were asked to compare their responses of pre and post science-related attitudes to quantitatively analyze the commonalities and differences of the two tests. To find out more characteristics, qualitative data such as daily records and interview were also gathered and analyzed. The major results of the study are as follows. First, for the paired t-test, there was no statistically significant difference between separate pre-test scores and retrospective pre-test. There was a very high correlation between the separate pre-test scores and the retrospective pre-test. Second, there were significant differences in all seven sub-factors of science-related attitudes between the retrospective pre-test and the post-test. Third, the separate pre-test scores showed a slightly higher tendency than the retrospective pre-test scores. This suggests that the response shift bias appears when it is performed the separate pre-test in affective domain. As a result of the interview, it was found that the evaluation standards of separate pre-test did not match with those of post-test. Forth, internal consistency reliability of the retrospective pre-test was higher than that of the separate pre-test. However, there were significant differences in six factors of science-related attitudes excluding the 'social implications of science' between the separate pre-test and the post-test. Based on these results, the retrospective pre-post test design provides simplicity and convenience to both respondents and investigators, as it is done with one test. The retrospective pre-post test design can be regarded as a valid design for the self-report measurement of affective domain on a single experimental group.

• East Asian mathematical journal
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• v.29 no.2
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• pp.169-187
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• 2013

The purpose of this study is to analyze whether mathematics education course can improve secondary pre-service math teacher' belief and correlation on pre-service math teacher' belief and mathematics education achievement. In order to achieve this purpose, the test was conducted to the subject of 34 pre-service secondary math teachers of the grade 2 and grade 4 who were chosen from H university in D city and we analyzed the results. Findings on this study are as follows. First, there was meaningful difference in the pre-service math teacher' belief with significant level of 0.05. This proved that mathematics education course was effective on improving pre-service math teacher' belief. Second, there was not meaningful correlation in the pre-service math teacher' belief and mathematics education achievement.

• Molecules and Cells
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• v.41 no.10
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• pp.889-899
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• 2018

Intrinsically disordered proteins (IDPs) are highly unorthodox proteins that do not form three-dimensional structures under physiological conditions. The discovery of IDPs has destroyed the classical structure-function paradigm in protein science, 3-D structure = function, because IDPs even without well-folded 3-D structures are still capable of performing important biological functions and furthermore are associated with fatal diseases such as cancers, neurodegenerative diseases and viral pandemics. Pre-structured motifs (PreSMos) refer to transient local secondary structural elements present in the target-unbound state of IDPs. During the last two decades PreSMos have been steadily acknowledged as the critical determinants for target binding in dozens of IDPs. To date, the PreSMo concept provides the most convincing structural rationale explaining the IDP-target binding behavior at an atomic resolution. Here we present a brief developmental history of PreSMos and describe their common characteristics. We also provide a list of newly discovered PreSMos along with their functional relevance.

• The Mathematical Education
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• v.52 no.2
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• pp.175-190
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• 2013

The purpose of this article is to suggest using portfolio for professional development of secondary pre-service mathematics teachers based on actual application case. To achieve this goal, 28 pre-service mathematics teachers developed their own portfolios in the regular study course for one semester under the pre-planned components of portfolio. Then they participated in the survey of their beliefs in mathematics and mathematics education and in the structured interview for drawing implications of using a pre-service mathematics teacher portfolio. According to the collected data, developing a pre-service mathematics teacher portfolio made a significant difference in beliefs of mathematics teachers' roles and showed the potential to improve the professional development of pre-service mathematics teachers as well as their learning. Continued investigation for more effective components of a pre-service mathematics teacher portfolio would be needed.