• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.113-116
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• 2002

In this paper dynamic characteristics were investigated of the perception of a bound image width. Subjective evaluation tests were carried out of the width of a sound image when its presentation region was moved in the horizontal plane. As a result, the sound image width was perceived narrower or wider than the actual presentation region when the sound source width was decreased or increased, respectively. The result obtained shows that a phenomenon which is a kind of auditory motion aftereffects was occurred in the perception of a sound source with changing its width.

• 한국과학교육학회지
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• 제24권1호
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• pp.17-28
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• 2004

The purpose of this study is to determine the patterns of differences between genders in science achievement. Eleventh grade, 140 female and male students were sampled from a school in Seoul. According to the analysis results of pilot study, 20 items were finally selected for the main study. To sharpen our interpretations of the factors and provide some confirmation, we supplemented the statistical analysis with a more detailed cognitive study of the items using think-aloud protocols and interviews with student test takers. The analysis of this study took into account the different item formats, contexts, and presentation styles. The findings are as follows: First, there was no significant gender difference between multiple-choice and open-ended items. Second, male students achieved significantly better in the context of everyday life in multiple-choice items. Third, male students favored items presented as written texts. Fourth, in problem-solving process, female students tend to apply their science concepts, whereas male students tend to apply their everyday experiences. The results of this investigation indicate that gender difference in science achievement depends heavily on item characteristics.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2001년도 추계학술발표회
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• pp.9-12
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• 2001

MTBE is a gasoline additive which is widely used in the world. Its use on the air pollution reduction has been proved very effective, but has generated serious problems of groundwater contamination. Its use will be banned gradually by US EPA and other states governments in US. In Korea, it has been used since 1987 and its consumption reaches about 700, 000 tons/year. Any problems related to the groundwater contamination has not been reported in Korea, yet due to the lack of investigation. In this presentation, I raise the MTBE problems with examples of MTBE contaminations in the US.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제16권4호
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• pp.269-272
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• 2013

Association between celiac disease and intussusception has been reported in adult. Although intussusception is common in children, it rarely has been reported in association with celiac disease. Two children, 5 and 7 years old, with celiac disease are reported here, whose initial presentation was intussusception prior to investigation for concomitant failure to thrive. They presented with acute and severe abdominal distention with vomiting, and donuts and pseudo- kidney appearance in abdominal ultrasonography. One patient's intussusception had reducted spontaneously, however the other had required surgery. In investigation for concomitant failure to thrive, tissue transglutaminase levels were very high and duodenal biopsies revealed celiac disease. Thus celiac testing is recommended in children with intussusception and growth failure.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2012년도 춘계학술대회
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• pp.52-54
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• 2012

Saigon-Vungtau fairway is the main and the most important fairway of the major economic areas: Ho Chi Minh City, Dong Nai Province and Ba Ria-Vung Tau Province in Vietnam. In last 5 years, 80% of accidents happened on the fairway were caused by collision and contact/impact. This presentation study on marine traffic investigation in the adjacent of the fairway to find out problems related to marine traffic for improving Marine Traffic Safety Management in this area.

• 천문학회보
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• 제42권2호
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• pp.63.3-64
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• 2017

KIC6118779 is an over-contact binary system having a short orbital period of about 0.36 days. The photometric data for this system are acquired by the observations of Kepler mission in the long cadence mode having a time resolution of about 30 minutes. It means that the Kepler light curves of the system may be strongly affected by phase smearing effect and the analysis of them without consideration of the phase smearing effect may result in wrong stellar properties. Additionally, this system also shows dynamical variation of light curve resulting from spot activity. For all those reasons, it is difficult to investigate KIC6118779, and the investigation should be carried out carefully. In this presentation, we introduce the phase smearing effect and carry out the light curve modeling with the 2015 version of the Wilson-Devinney binary code considering the phase smearing effect. Our results show that the system is a deep over contact binary system and has extremely low mass ratio of about 0.12. Moreover our spot modeling implies the cyclic migration of a big cool spot on the massive component.

• 한국과학교육학회지
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• 제25권1호
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• pp.26-40
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• 2005

Based on the Vygotskian perspective that a learner's thinking is constituted in his or her talk and the assumption that student talk in the classroom may occur in more than one way, this study examined discursive practices of students in Korean high school science classrooms. Data came from $11^{th}$ grade earth science classrooms where the Group Investigation (GI) method was implemented. Data source included verbatim transcripts developed from video recordings of class sessions in which students presented their science projects to the whole class and exchanged questions and answers during the presentations. The analysis of the videotape transcripts revealed five different modes of student talk, including 1) retrieving information, 2) reformulating information, 3) building on one's own experience, 4) elaborating current understanding, and 5) negotiating meanings with others. Considering that each of the five modes had different value for learning science, it was recommended that the teacher should engage students in more active modes of discourse and guide them into more sophisticated understanding of science.

• International Journal of Fluid Machinery and Systems
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• 제3권4호
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• pp.285-291
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• 2010

To provide required flow rates of cooling or circulating water properly, approach flow conditions of vertical pump systems should be in compliance with state of the art acceptance criteria. The direct inflow should be vortex free, with low pre-rotation and symmetric velocity distribution. Physical model investigations are common practice and the best tool of prediction to evaluate, to optimize and to document flow conditions inside intake structures for vertical pumping systems. Optimization steps should be accomplished with respect to installation costs and complexity on site. The report shows evaluation of various approach flow conditions inside a compact waste water pumping station. The focus is on the occurrence of free surface vortices and the evaluation of air entrainment for various water level and flow rates. The presentation of the results includes the description of the investigated intake structure, occurring flow problems and final recommendations.

• 한국환경과학회지
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• 제19권6호
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• pp.747-753
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• 2010

It follows in quality and sewage exclusion method of the investigation objective sector and the Combined Sewer Overflows which is suitable in regional characteristics and the confluence area against the rainfall initially a flow and the medulla and measurement - it analyzes the initial rainfall outflow possibility control plan which is suitable in the domestic actual condition and it proposes the monitor ring plan for the long-term flow and pollution load data accumulation. From the research which it sees the Infiltration water/Influent water and CSOs investigation it passes by the phase of hazard chain and Namwon right time 4 it does not hold reverse under selecting, Measurement it used the hazard automatic flow joint seal Sigma 910 machine and in case 15 minute interval of the I/I, it measured a flow at case 5, 15 minute standing of the CSOs. The water quality investigation for the water leakage investigation of the I/I and the sewage from the point which is identical with flow measurement during on-the-spot inspection duration against 6 items which include the BOD sampling and an analysis, when the rainfall analysis for CSOs fundamental investigation analyzed against 18 items which include the BOD sampling. Consequently, for the optimum interpretation invasion water / inflow water of the this investigation area day average the lowest flow - water quality assessment veterinarian optimum interpretation hazard average per day - lowest flow - it averages a medulla evaluation law department one lowest flow evaluation technique and it selects, it presentation collectively from here it gets, position result with base flow analysis of invasion water / inflow water.

• 대한화학회지
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• 제60권5호
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• pp.327-341
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• 2016

This study explores the effective visual resources in the “regularity in chemical reactions” unit of ninth grade science textbooks (2009 revised version). The frequency and role of visual resources were initially examined, and the students’ perceptions of visual resources were investigated. The results of the analysis represented the learning material presentation (68%), motivational categories (14%), guide to inquiry procedures (9%), and inquiry results and summaries (8%). According to the investigation of the students’ perceptions of visual resources, the most effective visual resource for motivation is a photograph depicting physical and chemical changes, such as in bread baking and the most effective for learning material presentations in mass conservation, definite proportion, and stoichiometric concept units were a cartoon, graph, and formula representing stoichiometric phenomena, respectively. The most effective resource for guide to inquiry (experimental) procedures were photographs of both instruments and sequential experiment processes; and in the inquiry results and summary category, incomplete tables and graphs for students to work on themselves. The aims of this research are to increase the usefulness of visual resources in the teaching-learning activity and provide informative supplements for the development and improvement of visual resources, according to the students’ perceptions.