• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.5
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• pp.141-147
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• 2021

In this paper, in order to improve the utilization of hyperspectral large-capacity data feature information by reducing complex computations by dimension reduction of neural network inputs in embedded systems, the band selection algorithm is applied in each subset. Among feature extraction and feature selection techniques, the feature selection aim to improve the optimal number of bands suitable for datasets, regardless of wavelength range, and the time and performance, more than others algorithms. Through this experiment, although the time required was reduced by 1/3 to 1/9 times compared to the others band selection technique, meaningful results were improved by more than 4% in terms of performance through the K-neighbor classifier. Although it is difficult to utilize real-time hyperspectral data analysis now, it has confirmed the possibility of improvement.

• School Mathematics
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• v.14 no.1
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• pp.151-163
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• 2012

In 2006 with the revised national curriculum, Elementary mathematics teaching and learning methods are presented in the following ways. Learners explore the way through the operational activities of the teachers and students with learning and learners' active learning activities, etc., and an active learning based on the principle of attention to learning how to maximize the effectiveness are required. In this study, from first grade through sixth grade elementary school mathematics textbooks for all learning activities presented in 10 different types were investigated This result of 5 contents area of number and operation, geometry, probability and statistics, measurement and patterns and problem solving and divided into low, middle, and hight three were intentional. In addition, teachers are looking forward to this result was compared with the type of activity.

• The Mathematical Education
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• v.48 no.4
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• pp.399-417
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• 2009

The purpose of this study was to explore the adaptability of U.S. multiple-choice items to measure Mathematical Knowledge for Teaching (MKT) in Korea. For this purpose, the authors selected the number and operations form B which was developed by Learning Mathematics for Teaching (LMT) project at the University of Michigan and then adapted items in terms of general cultural context, school cultural context, mathematical substances, and language in Korea. The survey was administrated to 77 Korean in-service teachers who had more than three years of teaching experiences. Based on the survey, the authors compared the data to that of U.S. teachers who had participated California's Mathematics Professional Development Institute. As a result, the survey measures less knowledge Korean teachers than more knowledgable Korean teachers and there are strong correlations of relative item difficulties between Korean teachers and U.S. teachers for both Content Knowledge (CK) items and Knowledge of Content and Students (KCS) items. This study implies the future direction for developing items to measure teacher knowledge as well as designing effective teacher education programs.

• Journal of the Korea Computer Industry Society
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• v.5 no.9
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• pp.891-902
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• 2004

Membership changing is deeply associated with scalability problem for group key management. If members of the group join or leave, new group key has to be geneerated and distributed to all remaining members of group. Group key changing is perform for group controller. The following parameters are important evaluating criteria of multicast key management scheme that generate and deliver new keys for rekeying: the number of keys stored by both controller and member, messages to deliver, keys to initially be delivered by controller, blocking capability of collusion attacks, messages to deliver at the batch rekeyng. Batch rekeying can reduce messages to deliver and operation costs of generation for message rather than removing members sequentially in fashion one after another. We propose efficient batch rekeying scheme applicable to Pegueroles scheme using random number and prove to be a efficient group key scheme for enhanced Pegueroles model with batch rekeying capability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.12A
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• pp.1333-1339
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• 2004

In IS-95 and IMT-2000 systems using variable code rates and constraint lengths, this paper limits code rate 1/2 and constraint length 3 and states the effective reduction of PM(Path Metric) and BM(Branch Metric) memories and arithmetic comparative calculations with appling PVSL(Prototype Vector Selecting Logic) and LVQ(Learning Vector Quantization) in neural network to simplify systems and to decode forwardly. Regardless of extension of constraint length, this paper presents the new Vierbi decoder and the appied algorithm because new structure and algorithm can apply to the existing Viterbi decoder using only uncomplicated application and verifies the rationality of the proposed Viterbi decoder through VHDL simulation and compares the performance between the proposed Viterbi decoder and the existing.

• The Mathematical Education
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• v.56 no.1
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• pp.1-17
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• 2017

The purpose of this study is to analyze the differences between the cognitive load of mathematics textbooks based on storytelling and traditional mathematics textbooks that are presented to students. In order to verify this, we have selected two 4th grade classes in elementary school that were identified as a homogeneous group through prior testing, and thus were separated into experimental group and comparative group. Then, without the teacher's lessons, the experimental group learned from mathematics textbooks based on storytelling and the comparative group learned from traditional mathematics textbooks. Afterwards, the two groups' cognitive load was measured through a questionnaire, and the following results were obtained: In the 'mental effort' and 'self evaluation' categories, the students that learned from the mathematics textbook based on storytelling showed higher scores than the students that learned from the traditional mathematics textbook. also there was statistically significant difference in some items. However, no statistically significant difference was found in the remaining categories 'task difficulty', 'self evaluation', and 'material design'.

• Journal of the Korean School Mathematics Society
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• v.8 no.4
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• pp.423-444
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• 2005

Despite the importance of number sense, computational skills have been emphasized in elementary mathematics curriculum. There is lack of research on number sense. Against this background, this study analyzed the way 137 sixth grade students coped with routine computation problems and with problems requiring number sense. Students performed better on the computation tasks than on the number sense tasks. With regard to the number sense tasks, many students had a tendency to implement direct computation rather than to use number sense appropriate to the given contexts. Students also had difficulties in making use of effective benchmarks or applying the knowledge of number and operation to various problem contexts. An implication is that students should explore multiple tasks requiring number sense as an integral part of their mathematics learning in order to develop number sense.

• 한국공간정보시스템학회:학술대회논문집
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• 2000.06a
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• pp.109-122
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• 2000

기존의 통합 시스템은 이미 구축된 자윈을 재활용하여 데이타의 구축비용을 줄이고자 하는 의도에서 연구되었다. 특히 GIS에서는 공간 데이타의 규모가 방대하므로 그 구축비용이 더욱 증가한다. 이로 인해 공간 데이타를 위한 통합 시스템의 필요성이 대두되다. 최근 웹의 사용자 수와 그 응용의 수가 증가함에 따라 웹에서의 공간 데이타를 이용한 응용의 필요성이 승가하고 있다. 이에 따라 웹 환경에서 분산된 공간 데이타의 통합 시스템이 요구된다. 기존의 미디에이터(Mediator)를 사용한 통합에 비하여 웹을 기반한 공간 데이타의 통합은 웹의 환경적 특성과 공간 데이타의 크기와 형태 등을 고려해야 한다. 본 논문에서는 OGC(OpenGIS Consortium)의 웹 매핑 기술인 WMT(Web Mapping Testbed)의 중첩 맵 서버 (Cascading Map Server)를 사용하여 공간 데이타를 통합한다. 통합 과정에서 요구되는 표준화된 데이타 모델과 인터페이스는 OGC가 최근 제안한 GML(Geography Markup Language)과 웹 맵 서버 인터페이스를 이용한다. 본 논문은 XML의 XLink와 XPointer의 개념을 가진 융합 서비스(Fusion Service)기법을 중첩 맵 서버에 도입한 융합 맵 서버(Fusion Map Server)를 제안한다. 이러한 통합 방식은 데이터 사이의 관계성을 고려한 링킹 기반 통합이므로 통합 응용의 복잡성을 줄일 수 있을 뿐만 아니라 물리적 변환 등에서 생성되는 연산 비용을 줄일 수 있는 장점이 있다.

• Journal of Korea Spatial Information System Society
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• v.11 no.4
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• pp.85-88
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• 2009

In multimedia database systems, the nearest neighbor Query occurs frequently and requires the processing cost higher than other spatial Queries do. It needs the measurement of search distance that the number of searched nodes and the computation time in an index can be minimized for optimizing the cost of processing the nearest neighbor query. The circular location property of objects is considered to accurately select the nodes which will be searched in the nearest neighbor query. In this paper, we propose the processing method of nearest neighbor queries be considered a circular location property of object where the search space consists of a circular domain and show its characteristics. The proposed method uses the circular minimum distance and the circular optimal distance, the search measurement for optimizing the processing cost of nearest neighbor queries.

• East Asian mathematical journal
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• v.31 no.2
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• pp.275-299
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• 2015

The purpose of this study is to provide an opportunity for better understanding and application of 2009 revised elementary school mathematics textbooks through survey data and focus group interview on structures of textbooks. First, We collect online survey results which 2333 elementary school teachers participated. Next, We interview focus group(8 teachers) about shapes of textbooks, quantity of learning contents, activities and problems for evaluation in the mathematics lessons. Storytelling is especially issued in the 2009 revised mathematics curriculum. We intensively discuss learning and teaching methods with application of storytelling textbooks; interests of students, role of storytelling textbooks etc. As results of analysis, the positive rate to use the 2009 revised textbooks is relatively high about shapes and activities of textbooks. But there is more considered about storytelling method. Storytelling may be positive on improvement of learning interests and participation of students. In order to develop these advantages, studies in relation of storytelling are more proceeded and teaching materials for teachers are required effectively in order to applicate to the elementary school.