• Proceedings of the Korean Information Science Society Conference
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• 2002.04b
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• pp.142-144
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• 2002

데이터 웨어하우스는 기업의 의사 결정을 지원하기 위해 기업의 운영 데이터베이스로부터 추출한 데이터의 집합으로써 OLAP 분석에 이용된다. OLAP은 이들 데이터를 다양하게 분석할 수 있도록 다차원 데이터로 표현하고 이를 활용하여 복잡한 분석 질의 처리 및 다차원 데이터 분석에 활용한다. 이러한 OLAP의 다차원 데이터를 관계형 데이터베이스에서 표현하기 위해 스타 스키마가 널리 사용된다. 또한 다차원 데이터와 데이터 웨어하우스는 방대한 분량를 갖는 전체 기업의 데이터를 표현하고 있어 이를 설계하는 것이 매우 복잡하고 많은 노력이 소요된다. 따라서 이를 설계하기 위한 체계적인 설계 방법론이 필요하다. 데이터 웨어하우스의 원천 데이터가 되는 운영 데이터베이스는 현재 ER 도형을 이용하여 개념적인 방법으로 널리 설계되고 있다. 따라서 이 논문에서는 ER 도형으로 설계된 운영 데이터베이스로부터 데이터 웨어하우스를 설계하는 개념적인 방법론을 제시한다. 이에 따라 OLAP 분석을 위해 사용할 수 있는 다양한 유형의 스타 스키마에 대해 ER 도형으로 표현/변환하는 방법을 제시한다. 이를 통해 자신이 원하는 다차원 데이터를 얻기 위해 유지해야 할 데이터 웨어하우스를 ER 도형을 이용하여 개념적으로 편리하게 설계하는 방법/지침을 제공하며, 나아가 해당 유형의 스타 스키마가 갖는 의미를 개념적으로 쉽게 전달할 수 있도록 하였다.

• The Journal of Korean Association of Computer Education
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• v.17 no.5
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• pp.43-51
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• 2014

This study has purpose on analyzing the error types which are identified after middle and high school students perform the online programming assignments and also has the purpose on the analysis of correlation between the frequency of error occurrence according to academic achievement level in programming concept learning and types of errors analyzed previously. For this study, the syntax, logical, and coding errors are analyzed from the performed results of programming research assignment for 88 students. Analyzed results show that the logical error has the highest occurrence rate of 69.3% among three types of errors, and it has been shown meaningful difference in the frequency of error occurrence between three achievement level groups of high, middle, and low. In the correlation analysis of achievement level and error types, it shows negative relationship between logical error and coding error, and therefore it can be concluded that as achievement level is higher, both logical and coding errors tend to occur less. In the correlation analysis in error types, it shows positive relationship between syntax error and coding error.

• The Journal of Korean Association of Computer Education
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• v.16 no.6
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• pp.71-81
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• 2013

This study was executed to give a help in planning and implementing online learning. For this purpose this study investigated the effect of contents presentation types, levels and metacognition on concept map composition and learning process in online learning. Learning contents types were two, meaning-centered or context-centered. Contents levels were divided into two; basic or deficient. Metacognition was divided into two levels according to the scores of scale. Results showed that meaning-centered type(M=45.00, SE=1.97) got better scores in concept map than context-centered(M=34.71, SE=1.98), Presentation levels and metacognition had no significant influence on concept map. There were interaction effect(F=.002, p>.05) between presentation levels and metacogntion levels. The upper group in metacognition got higher score in deficient types whereas the lower group got higher score in basic type. In online learning process, learner's metacognition was an important factor to complement the contents' defect and lack.

• Journal of The Korean Association For Science Education
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• v.31 no.5
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• pp.734-744
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• 2011

The purpose of this study was to identify middle school students' mental models on plate tectonics and to compare the mental models of verbal-learning-style students with those of visual-learning-style students. 94 student participants in 9th grade were requested to draw and explain three topics; generation of magma, the formation of the mountain range and the interior of the Earth. The criterions for analyzing the mental models are derived from the data of the drawing task. The research results were as follows: The mental models on the generation of magma were classified as 'unstable model,' 'partial casual model,' 'causal model,' and 'conceptual model.' On the other hand, the mental models on the interior of the Earth were classified as 'static unstable model,' 'dynamic unstable model,' and 'conceptual model.' Students holding 'unstable model' were unable to relate the plate collision and the magma generation. They showed a variety of alternative conceptions of study areas, such as 'magma is generated from the core' and 'the mountain is formed by rising of the plates themselves.' Also, visual-learning-style students showed higher proportion of conceptual models and lower proportion of unstable mental models than verbal-learning-style students on three topics. The findings revealed that the students tend to have different concepts on the plate tectonics depending on their learning style.

• Journal of Science Education
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• v.36 no.2
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• pp.369-380
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• 2012

The purpose of this study was to investigate middle students' conceptions of buoyancy. The questionnaires composed of 9 items which asked the reasons for situations with buoyancy; recognized of buoyancy, the facts affecting buoyancy(bottom of the Area of the object, the shape of the object, the depth of the object in the water, amount of water, the degree of the object submerged in the water, volume of the object, weigh of the object), the relationship between the amount of replaced fluid and buoyancy. The subjects were 140 students from the Busan Area who answered questionnaires composed of 9 items which asked the reasons for situations with buoyancy. Among the 140, 132 students were selected who answered all of question in the test. The students' answer types were follow: 1. Related to the shape of the submerged object, students answered that buoynacy depended on the bottom dimensions or the surface area of the object. 2. Students confused press, water press and buoyancy, who answered buoyancy was great when the water press was great. 3. Students answered that the weight and the size of the buoyancy of the object was same in the water. 4. Students answered, gravity was smaller in the water. Students recognized the existence of buoyancy but the reason of the answer depend on their experience. Also students answered using the words that water pressure, pressure, force instead of buoyancy. Students didn't understand the factors affecting the buoyancy. Many students responded that buoyancy was changed depend on weight of object, sinking depth, shape and others. It was considered that these responses didn't understand the cause of buoyancy.

• Journal of The Korean Association For Science Education
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• v.22 no.2
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• pp.252-260
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• 2002

The types and the characteristics of students' responses to anomalous data in studying 'boiling point' were investigated, and the degree of cognitive conflict and conceptual change were compared by students' cognitive variables. Tests regarding field dependence-independence and logical thinking ability, a preconception test, and a test of responses to anomalous data were administered to 137 sixth graders. Among them, 90 students whose preconceptions were consistent with the presented initial theory were selected. After learning the scientific concept, students' conceptual change was examined. Six types of responses identified were as follows: Rejection, reinterpretation, exclusion, uncertainty, belief decrease, and theory change. The main responses were rejection (33%) and theory change (39%). The results of Mann-Whitney U test indicated students who were field independent and had higher logical thinking abilities felt more cognitive conflict and exhibited more conceptual change.

• Journal of The Korean Association For Science Education
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• v.21 no.4
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• pp.648-657
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• 2001

Using the concepts on the need of existence of living things, we investigate students' concepts on interdependence concepts between living things. The purposes of this study are to identify components of conceptual ecologies influencing on students' concepts and to describe the relations between those components and their concepts. The subjects of this study are 4 boys, 2 girls in the 3rd grade of middle school. The sources of data used in this study include a questionnaire, interviews and observation of the discussion class. Then, all data collected through each methods are compared and summarized in the relation to the questions of research. As a conclusion, it reveals that students' concepts are connected with several cognitive or affective components. Especially, the major components influencing on students' concepts are their metaphysical beliefs, conceptions includes other fields. These components function as constraints. Given these results, a teacher who want to teach a new concept to students should consider their characteristics and the components of conceptual ecology.

• Journal of The Korean Association For Science Education
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• v.34 no.4
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• pp.335-347
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• 2014

Size/scale is a central idea in the science curriculum, providing explanations for various phenomena. However, few studies have been conducted to explore student understanding of this concept and to suggest instructional approaches in scientific contexts. In contrast, there have been more studies in mathematics, regarding the use of number lines to relate the nature of numbers to operation and representation of magnitude. In order to better understand variations in student conceptions of size/scale in scientific contexts and explain learning difficulties including alternative conceptions, this study suggests an approach that links mathematics with the analysis of student conceptions of size/scale, i.e. the analysis of mathematical structure and reasoning for a number line. In addition, data ranging from high school to college students facilitate the interpretation of conceptual complexity in terms of mathematical development of a number line. In this sense, findings from this study better explain the following by mathematical reasoning: (1) varied student conceptions, (2) key aspects of each conception, and (3) potential cognitive dimensions interpreting the size/scale concepts. Results of this study help us to understand the troublesomeness of learning size/scale and provide a direction for developing curriculum and instruction for better understanding.

• Journal of Korean Library and Information Science Society
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• v.42 no.2
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• pp.237-255
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• 2011

This study is to find new methods in describing material type as content type and carrier type for the improvement of OPAC retrieval and the embodiment of work and expression of FRBR. It is hard to describe type vocabulary in cataloging because division of content and carrier taxonomy in KCR4 and KORMARC is not distinct. This study is to review the characteristics of material type list in RDA and ISBD(2010), and to examine the various type vocabulary and description methods of videorecording, soundrecording, and cartographic by retrieving KERIS DB. As a result, there is no consistency in applying type vocabulary between KCR4 and KORMARC. Also, libraries use the mix of content and carrier or detailed carrier vocabulary for local use. Therefore, it is need to define the function of GMD as content type, to expand and correct content and carrier vocabulary, and to express both content and carrier type in citation and detailed display. This study will contribute to embody the expression of FRBR.

• Proceedings of the Korean Society for Information Management Conference
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• 1995.08a
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• pp.115-118
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• 1995

DDC의 사회과학(300) 분야에서 특정 개념을 표현하기 위하여 사용되고 있는 합성주를 분석하여 7가지 유형으로 파악하고, 적용상의 일관성 여부를 검토하였다.