• Journal of KIISE:Databases
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• v.32 no.4
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• pp.429-440
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• 2005

As rapid improvement in electronic technologies makes sensor hardware more powerful and capable, the application range of sensor networks Is getting to be broader. The main purpose of sensor networks is to monitor the phenomena in interesting regions (e.g., factory warehouses, disaster areas, wild fields, etc) and return required data. The k Nearest Neighbor (KNN) query that finds k objects which are geographically close to the given point is an Important application in sensor networks. However, most previous approaches are either seem to be impractical or are not energy-efficient in resource-limited sensor networks. In this paper. we propose an efficient KNN query processing method in sensor networks. In the proposed method, we dynamically increase searching boundary, if necessary, and traverse nodes inside the boundary until finding k nearest neighbors. Since only the representative sensor nodes are visited, our algorithm reduces a number of messages. We show thorough experiments that the proposed method performs better than the existing method in various network environments.

• Journal of Digital Convergence
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• v.14 no.3
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• pp.453-464
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• 2016

This study started from the basis of necessity on the researches which asserts that parental rearing behavior in the modern society should change reflecting the social change of sociocultural environment. For this, parental rearing behavior of social constructivism and existing parental rearing behavior were contemplated while construct of parental rearing behavior was explored on the basis of main causes from Vygotsky's theory in order to prepare paradigm of new parental rearing behavior. As far as the method of study goes, various literature from relevant scholars were analyzed, centering various previously conducted studies pertaining to parental rearing behaviors as well as Vygotsky's theory. Also, the validity of the contents was confirmed through consult and revision from three experts. As the result, five factors were extracted. First, factor of cooperative interaction on social interaction. Secondly, emphasis on Internalization factor on social constructive behavior. Thirdly, potential development factor in zone of proximal development. Fourthly, instructional conversation factor as semiotic medium. Lastly, assistance factor as scaffolding. As a result, new paradigm of parental rearing behavior was presented and opened a prospect in developing the touchstone of parental rearing behavior pursuant to social constructivism.

• Proceedings of the Optical Society of Korea Conference
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• 2000.08a
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• pp.94-95
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• 2000

파장보다 작은 구멍을 통한 빛의 회절을 다루는 문제는, 최근 근접장 광학의 발달과 더불어서 많은 연구가 되고 있다. 이러한 작은 구멍은 근접장 주사 광학 현미경(NSOM)에서의 탐침(probe)으로 사용되므로, 여기에서 일어나는 빛과 탐침의 상호작용을 잘 이해하는 것이 중요하다.$^{(1)}$ 본 연구에서는 작은 구멍 주변에 선형 스크래치가 있을 때, 구멍을 통한 빛의 회절 분포를 먼 장(far field) 영역에서 관측하였다. 먼 장 분포를 분석해 본 결과, 구멍 주변의 선형 스크래치에 의한 효과가 나타나는 것을 볼 수 있었다. 이것은 구멍 주변에서 발생한 표면파가 금속 표면을 따라가면서, 주변의 스크래치와 상호 작용한 결과로 보인다. (중략)

• Journal of The Korean Association For Science Education
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• v.27 no.9
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• pp.832-847
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• 2007

The purpose of the study was to analyze and interpret parent-child dyadic discourses in depth with emphases on the ZPD system in a museum, an informal learning setting. Second graders and their parents from Seoul and its environs were voluntarily participated in the study. Data were collected from the museum documents, the photos of exhibits, and the video recordings of dyadic discourses at and between exhibits. The documents and the photos were analyzed to investigate what the topics, medium and goals of the exhibits were. The video recordings were all transcribed and analyzed to understand what and how they talked to each other through the lens of the ZPD system; situation definition, intersubjectivity, and semiotic mediation, The results of the study consisted of two parts. First, it showed that parent-child dyadic discourses were categorized in four: (1) within the actual developmental level; (2) in the zone of proximal development; (3) toward the potential developmental level; and (4) out of developmental level. The most common categories were the dyadic discourses within the actual developmental level and in the zone of proxima I development. Second, the representative cases in each categories were described and interpreted to understand the nature of parent-child dyadic discourses. It can be concluded that we gained some important understandings of an intrinsic attribute of parent-child discourses in a museum, an informal learning setting. Based on the results of the study, it can be suggested that museums make efforts to cultivate the affordance of exhibit environment to promote visitor's learning.

• Journal of the Korea Convergence Society
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• v.10 no.7
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• pp.71-76
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• 2019

The purpose of this study is to investigate the effect of action learning methods and practices, which have a research focus on learner-centered teaching after training students to use collaborative learning practices from the viewpoint that the learners acquire English skills through peer correction activities based on sociocultural learning theory[1]. From March 1, 2018 to June 15, 2018, one control class and one experimental group were selected from the general freshman English courses. The experimental group attended classes centered on collaborative writing activities using action learning and cooperation techniques, and the control group attended classes lecture style and rote learning methods to teach writing. The result of study has shown that, for the experimental group, there have been statistically significant results in the production of writing, such as the number of words, the number of sentences, and sentence length. Learners could share the knowledge or ideas of others in their learning relationships with more regular basis.

• The Mathematical Education
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• v.49 no.2
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• pp.223-246
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• 2010

Goos(2004) introduced educational researchers' demand for change on the way that mathematics is taught in schools and the series of curriculum documents produced by the National council of Teachers of Mathematics. The documents have placed emphasis on the processes of problem solving, reasoning, and communication. In Korea, the national curriculum documents have also placed increased emphasis on mathematical activities such as reasoning and communication(1997, 2007).The purpose of this study is to analyze the impact of inquiry-oriented instruction with guided reinvention on students' mathematical activities containing communication and reasoning for science high school students. In this paper, we introduce an inquiry-oriented instruction containing Polya's plausible reasoning, Freudenthal's guided reinvention, Forman's sociocultural approach of learning, and Vygotsky's zone of proximal development. We analyze the impact of mathematical findings from inquiry-oriented instruction on students' mathematical activities containing communication and reasoning.

• Journal of Educational Research in Mathematics
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• v.22 no.4
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• pp.517-534
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• 2012

As observing the learning of middle school mathematics students for three years, I examined the relationship between students' procedural knowledge and their conceptual knowledge as they develop those knowledges in the rational number domain. In particular, I explored the implications of an unbalanced development in a student's conceptual knowledge and procedural knowledge by considering two conditions: (a) the case of a student who has relatively strong conceptual knowledge and weak procedural knowledge, and (b) the case of a student who has relatively weak conceptual knowledge and strong procedural knowledge. Results suggest that conceptual knowledge and procedural knowledge are most productive when they develop in a balanced fashion (i.e., closely iterative or simultaneously), which calls into question the assumption that one has primacy over the other.

• East Asian mathematical journal
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• v.34 no.4
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• pp.339-358
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• 2018

There has been researches for effective education. Among them, many researchers are striving to apply Zone of Proximal Development of Vygotsky which is emphasizing the social interaction in the field of teaching and learning. Researchers usually research based on individual or small group of students. However the math class in school relies on system that one teacher teach many students in reality. So this research will look for the effect that the teaching and learning program based on Zone of Proximal Development of Vygotsky by designing the teaching and learning program which is based on scaffolding structuring to overcome the zone of proximal development in many-students class. The results of this research are as follows: First, the studying program considered the theory of Vygotsky has a positive effect on improving the mathematical achievement of elementary student. Second, the studying program considered the theory of Vygotsky has a positive effect on improving the student's studying attitude upon mathematics.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04a
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• pp.767-769
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• 2003

컴퓨터와 무선 통신 기술의 발달로 인하여 LBS(Location based Service)와 같은 새로운 이동체 관련 서비스가 생겨나고 있다. 이와 같은 서비스들은 이동체들이 일정 주기를 가지고 자신의 정보를 서버로 전송하는데 이는 많은 디스크 입출력을 요구하게 된다. 그러므로 이동체 데이터에 대하여 다중 디스크를 이용한 병렬 입출력이 요구되고 있다. 그러나 기존의 디클러스터링 방법은 시간 도메인을 고려하지 않거나 공간 관련성만을 고려하여 디클러스터링을 하므로, 하나의 디스크에 특정 이동체의 궤적이 집중 되는 문제점이 있다. 이 문제점은 디스크의 병목현상으로 인한 느린 응답시간과 낮은 처리율의 결과를 발생시킨다. 그러므로 이동 객체의 빠른 질의 처리를 위한 새로운 디클러스터링 기법이 필요하다. 이 논문에서는 다중 디스크 기반의 시스템에서 이동 객체에 대한 영역질의시 빠른 응답시간과 높은 처리율물 얻기 위하여 새로운 디클러스터링 기법을 제시한다. 이동체 데이터의 궤적 MBB중 공간 좌표로부터 Predefined Disk를 생성하고 PDT-Proximity를 이용하여 시간 도메인을 고려하는 방법이다. 위와 같이 이동 객체의 특성을 고려한 새로운 디클러스터링 방법으로 시스템의 성능을 향상시킬 수 있다.

• Proceedings of the KSEE Conference
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• 2006.10a
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• pp.153-166
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• 2006

종래의 발파진동의 분석은 주로 대상 지장물에 대한 피해한계를 정립시키고자 하는 관점에서 발파공에서 비교적 원거리의 진동특성을 이해하기 위해 수행되어져 왔으나, 최근의 추이는 발파공 주변 암반의 손상의 정도를 평가하고자 하는 관점에서 그 분석영역의 범위가 근거리 진동특성 연구분야로 확대되고 있는 실정이다. 특히, 터널 발파작업시 여굴의 발생, 암반사면의 안정성 검토 등의 목적으로 암반의 손상영역을 평가하는데 있어서, 기초자료로 활용하고자 많은 연구가 이루어지고 있다. 암반손상의 평가를 위한 손상권 예측방법에는 여러 가지가 있으나, 그 중에서 대부분이 발파진동속도에 근거하고 있으며, 평가를 위한 진동의 예측은 기존에는 원거리 진동특성을 이용하여 근거리 진동을 예측하는 방법으로 그 손상의 정도를 평가하였으나, 최근의 추세는 계측기의 발달로 수m 이내의 진동특성의 계측이 가능하게 되었다. 이와 관련하여 국외에서는 수차례의 실험결과가 여러 문헌에서 보고되고 있으나, 실험장비의 선택 및 측정방법의 어려움 등의 연유로 국내에서는 아직까지 실시되지 못하고 있는 상황이다. 따라서, 본 연구에서는 실제 발파공 근접진동(near field vibration) 계측을 실시하고 그 결과를 분석하여 추후 지속적인 근거리 진동측정 방법 및 평가방법에 대한 기초자료를 제공하고자 하였으며, 무엇보다도 어떻게 계측할 것인가 하는 계측방법 및 그 계측결과의 분석방법에 대해 문제점 파악 및 향후 보완점에 대해 비중을 두어 수행하였다.