• Journal of KIISE:Databases
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• v.28 no.2
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• pp.188-203
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• 2001

멀티데이터베이스 시스템(multidatabase system)에서 여러 요소 데이터베이스(component database)에 대한 통합된 접근을 제공하기 위해서는 의미 이질성(semantic heterogeneity)이 탐색되고 해결되어져야 한다. 즉, 멀티데이터베이스 시스템은 각 요소 데이터베이스가 가지고 있는 정보의 의미를 이해하고 의미적으로 동등한 또는 유사한 정보들을 식별할 수 있어야 한다. 또한, 멀티데이터베이스 시스템은 사용자로 하여금 실세계의 동일한 정보를 가지고 있는 여러 다른 데이터베이스로부터 원하는 정보를 용이하게 획득할 수 있도록 해야 한다. 본 논문에서는, 요소 데이터베이스간의 의미 이질성을 탐색하고 해결하기 위하여 정보가 갖고 있는 개념간 의미관계에 기반한 의미망(semantic network)을 구축한다. 또한 의미질의어(semantic query language)를 제공하여 사용자가 스키마에 대한 사전 지식이 없이도 여로 자율적인 데이터베이스로부터 원하는 정보를 용이하게 획득 할 수 있도록 한다.

• Journal of Korean Library and Information Science Society
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• v.32 no.2
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• pp.121-144
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• 2001

The origins, definition and research area of information economics are outlined in brief. For the better understanding and discussion of information economics, some important concept that require examination, such as information economy, resources, uncertainty and information value are reviewed in detail. Furthermore, a brief history of model and issues surrounding models are examined. In particular, some applications of models related to social sciences have been investigated since these models hold tremendous potential as diagnostic and test tools in the practical and theoretical work of library and information science.

• Journal of the Korean Chemical Society
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• v.55 no.6
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• pp.1042-1055
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• 2011

The purpose of this study was to compare the conceptual and algorithmic problem solving ability on Boyle's law and Charles's law according to cognitive levels and characteristics of students in middle school 1st grade students. For this study, questionnaire items of conceptual and algorithmic problem solving ability were developed. and the problem solving ability according to cognitive levels and characteristics of students was compared. The long-term memory effect in conceptual and algorithmic problem solving ability according to cognitive levels was investigated, and problem solving process were analyzed by questionnaire items. In the results of this study, conceptual problem solving ability was higher than algorithmic problem solving ability in all cognitive levels. There was statistically significant difference in concrete operational period and transitional period students. In comparison of the long-term memory effect in conceptual and algorithmic problem solving ability, formal operational period students had the long-term memory effect. There was no statistically significant difference in the conceptual and algorithmic problem solving ability according to private education among the characteristics of students. But there was statistically significant difference in the problem solving ability according to experiences of the scientific activities and hopes to related scientific careers. From results of analysis of problem solving process, it is known that the students had a tendency to just remember macroscopic phenomena and to solve the problems without understanding the concepts. Therefore, teaching and learning strategy is necessary to replace unscientific concepts by the scientific concepts through identifying students's unscientific concepts in advance.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.52.2-52.2
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• 2016

해시계는 태양의 겉보기 운동을 통해 시간과 좌표계에 대한 이해를 도와주는 도구 중 하나이다. 국립고흥청소년 우주체험센터에서는 지평면 해시계와 수직 해시계를 덕흥 천문대에 설치하였다. 지평면 해시계는 관측자 자신의 그림자로 시각을 알 수 있도록 제작하였다. 관측자가 서는 곳에 아날렘마, 매월 1일의 위치 및 각 절기를 표기하여 균시차를 보정할 수 있게 하였다. 벽면 해시계는 가로 1.8m, 세로 1.8m 크기로 황동 주물제작하여 정남향으로 설치하였다. 눈금의 간격은 15분이며 균시차 보정은 하지 않았다. 두 해시계 모두 실제 센터의 경도에 맞춰 설계했으며 표준시와 시간차이를 보이게 했다. 지평면 해시계와 수직 해시계는 센터를 찾아오는 방문객에게 과학적 호기심을 일으키는 야외 체험전시물의 역할을 할 수 있을 것으로 기대하며 향후 해시계를 활용한 실험체험 프로그램을 통하여 청소년이 시간과 좌표계의 개념을 쉽고 명확하게 이해하는데 도움을 주고자 한다.

• Journal of KIISE:Software and Applications
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• v.28 no.6
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• pp.403-413
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• 2001

시스템이 진화와 노화를 거듭하는 경우 프로그램을 이해하는데 있어서 가장 정확한 문서는 기존의 시스템 자체에서 추출되어진 정보이다. 프로그램의 이해를 돕기 위한 분석기법중의 하나인 프로그램 슬라이싱은 1984년 Weiser에 의해서 소개되어진 이후 다양한 방향으로 연구가 진행되어져 왔다. 특히, 생성되어지는 프로그램 슬라이스가 사이즈가 크고 충분히 집약적이지 못하다는 문제점과 슬라이스의 계산방법이 효율적이지 못하다는 문제점을 극복하기 위하여 여러 가지 방법들을 시도되어 왔다. 본 논문은 고전적인 슬라이싱 기준에 새로운 파라미터를 추가함으로써 제외개념을 이용하여 보다 함수적으로 응집력있고, 사이즈가 작은 슬라이스를 생성하는 선택 슬라이스를 제시하며 이 선택슬라이스를 계산하기 위한 효율적인 방법을 기술한다. 데이터와 제어의 흐름을 이용하여 선택 슬라이싱을 정의하고, 선택 슬라이싱을 위한 종속그래프를 정의하고 이를 사용하여 선형적 시간 내에 선택 슬라이스를 생성하는 알고리즘을 기술한다.

• Journal of The Korean Association For Science Education
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• v.39 no.3
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• pp.441-456
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• 2019

In this study, we investigated pre-service science teachers' design for lessons using analogies in the perspectives of PCK. Three pre-service science teachers at a college of education in Seoul participated in this study. After the workshop of instructional analogies in science education, they practiced lessons using analogies in teaching practices. We observed their lessons and collected all of the teaching-learning materials. Semi-structured interviews were also conducted. The analyses of the results reveal that they dealt with mapping and unshared attribute only when using main analogies in their lessons and these processes were teacher-centered. There were some cases where they failed to adequately deal with analogies including concepts beyond the curriculum. When dealing with unshared attributes, they did not tend to accept students' opinions although they thought that unshared attributes are strongly related to misconceptions. Their understanding of assessment using analogies was not high. Assessment was relatively well done when they use student-centered analogies such as physical analogies or role-playing analogies. On the bases of the results, we suggest some educational implications for pre-service science teacher education.

• Journal of The Korean Association For Science Education
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• v.32 no.5
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• pp.841-854
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• 2012

The purpose of this study is to investigate the teaching methods of prediction, inference, and hypothesis. The major data source was gathered by in-depth interview of science teachers (about 50-80 minutes for each interview). The interviews were conducted using semi-structured interview protocol, which consisted of three major parts: (1) Teacher's definition of prediction, inferences, hypothesis, (2) Teaching methods of prediction, inferences, and hypothesis and (3)Reasons of teacher's inaccurate perceptions of prediction, inference, and hypothesis. All the interviews were audio-taped and transcribed. Topics in the questions were categorized. The results were as follows: Teachers recognized the importance of prediction, inferences, and hypothesis. But they didn't have an accurate conception and they have great difficulty in classifying and explaining the prediction, inferences, and hypothesis. To find out the teaching methods, researcher investigated the inquiry activities, teaching times, usage of terms, teachers' questions, and teaching difficulties. Reasons for having difficulty were lack of teaching competency, difficulties from the students, and problems in the present curriculum. Finally, we discovered that the reasons for teacher's inaccurate perceptions of prediction, inference, and hypothesis were two factors. One is internal factors, which include the lack of scientific inquiry process skills, burdens of science subject and lack of science education knowledge. The other is external factors, which include education system for evaluations and lack of teacher education. In conclusion, this study suggested establishing more elementary teacher education programs that include strengthened concepts of inquiry process skills and teaching methods.

• Journal of The Korean Association For Science Education
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• v.37 no.6
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• pp.1063-1073
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• 2017

This study analyzed the difficulties elementary school students have in role-playing analogy activities for concept learning of heat transfer. Eleven fifth graders were given an orientation class on role-playing analogy activity, a class for concept learning of heat transfer as presented in a textbook, and then they performed the role-playing analogy activity with concepts of heat transfer. After the classes, researchers investigated the difficulties students encountered through questionnaires and interviews. The following are results of the research: Difficulties that students faced in role-playing analogy activity can be classified into five types. First, students encountered difficulties in expressing the analogy. The students who had difficulties in expressing the analogy focused on expressions outside the science concepts or lacked understanding of the science concepts. They also had difficulties in expressing the analogy because they lacked the expressiveness of analogy or abilities in mapping errors. They had difficulties in expressing the planned role-playing analogy in a narrow space. Second, students also experienced difficulties in performing activities due to lack of understanding on activities or lack of experience. Third, students experienced difficulties in selecting roles because they preferred the specific role or unwanted the specific roles. Fourth, the members of group experienced difficulties in group activities because they did not concentrate on activities, failed to perform roles, or showed attitudes of an onlooker. Fifth, they experienced difficulties in communications due to unilateral communication, conflicts of opinions, and lack of opinions.

• Journal of the Korean Chemical Society
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• v.43 no.3
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• pp.340-350
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• 1999

This study was to analyze the articulation between chemistry contents of science textbooks at elementary and middle school level, to survey students ? perceptions on chemistry concepts, to establish guidelines for science textbooks that not only meet the needs of learners but also fit in a coherent way. In order to do this, we analyzed links of the aims and the organization of chemistry contents of elementary and middle school science textbooks, we also surveyed students' perceptions on chemistry concepts students had retained. The study revealed that the 6th middle school curriculum was almost a duplicate of the elementary school syllabus. And there was no interrelation between the organization of chemistry contents and the aim of the chapter which built up a logical picture of the world at a molecular level. It was also found that the lack of coherence between science textbooks in elementary and middle school was a major cause of student difficulty.

• Journal of Gifted/Talented Education
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• v.18 no.3
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• pp.591-612
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• 2008

In order to investigate the composition and characteristics of instructional objectives in a teaching-learning material for gifted elementary students in science, 217 instructional objectives across 13 themes in 4 areas of 'energy','materials', 'life' and 'earth' were analyzed by Bloom's revised taxonomy of educational objectives. Four types of factual, conceptual, procedural and meta-cognitive knowledge in knowledge dimension were all comprised in the objectives. Conceptual knowledge was primary constituent of the objectives and the proportion of factual knowledge was the least. On the other hand, all 6 categories of 'remember', 'understand', 'apply', 'analyze', 'evaluate' and 'create' in cognitive process dimension were also comprised in the objectives. The category of 'understand' was primary constituent and that of 'remember' was the least one. While conceptual knowledge in knowledge dimension was primary constituent of the objectives in 'energy', 'materials' and 'earth' areas, procedural knowledge was the most objectives in 'life' area. The least type of knowledge was factual knowledge in all 4 areas. In cognitive process dimension, the category of 'understand' was primary constituent and that of 'remember' was the least one in all 4 areas. In conclusion, it was showed that the instructional objectives in the teaching-learning material reflected the characteristics of educational objectives for gifted students in science.