• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.7
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• pp.1549-1555
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• 2009

The Relay node placement problem is one of the most important requirements for many wireless sensor networks because the lifetime of sensor networks is closely related with the placement of relay nodes which receive sensed data from sensor nodes and forward them to the base station. Relay node placement problem has focused at minimization of dissipated total energy of the sensor nodes in whole networks. However, minimum total energy causes the unbalance of consumed energy in sensor nodes due to different distances between relay nodes and sensor nodes. This paper proposes the concept of energy balance ratio and finds the locations of relay nodes using objective functions which maximize the energy balance ratio. Maximizing this ratio results in maximizing the network lifetime by minimizing the energy consumption of large-scale sensor networks. However, finding a solution to relay node placement problem is NP-hard and it is very difficult to get exact solutions. Therefore, we get approximate solutions to EBR-RNP problem which considers both energy balance ratio and relay node placement using constraint programming.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1164-1170
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• 2013

Since trees sequestrate carbon and reduce the level of its concentrations in the atmosphere, forests should be considered as carbon pools as well as timber producers. This study focuses on finding optimal harvest age when carbon sequestration from trees is accounted by forest managers. A dynamic programming employs a static volume matrix, and solves the harvest decision problems. If carbon value is accounted in a tree harvest decision model, the optimal harvest age increases. The harvest age of pine trees set by the government for national forests is longer than the optimal solution. It is possible to say that the managers of national forests put more values on the standing pine trees than the value of carbon sequestration. The regulation for private forests, on the other hand, ends up in a shorter harvest age than the optimal solution, and this discrepancy could lead to an inefficient private forest management.

• The Transactions of the Korea Information Processing Society
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• v.6 no.2
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• pp.512-521
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• 1999

SGML, defined as the ISO 8879, is a meta-language to define a document type, used as basic format for electronic documents. Since an SGML document is composed of a document type definition and a document instance conforms to the definition, it is necessary for SGML document authoring tools to compose and validate document type and document instance. In present, formal models and procedures for SGML documents are not defined, it's not easy to construct such tools. We propose a model of SGML authoring tool consists of SGML parser, document type definition editor, SGML document editor and style editor. We also introduce and implement formal procedure for each component. For user convenience, we adopted icon based visual programming method, and solved the HANGUL problems. The SGML authoring tool is implemented I Windows NT system using java and C++ programming language.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.3
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• pp.51-55
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• 2008

Purpose: To develop the program used in calculating and estimating anamorphic prisms used to construct an anamorphoser. Methods: If there is a program which can show the apex angle and the volume of prism which are decided by the refraction index of anamorphic prisms and the expanding ratio of incident beam, the production of anamorphic prisms can be done accurately. Moreover, it could become a convenient tool to the design and production of whole optical systems using anamorphic prisms. Developing this program, first, we had to induce formulas of prism that decide the apex angle and the arrangement angle of anamorphic prisms with the given refraction index of anamorphic prism and the given expanding ratio of incident beam. Then we programmed them by delphi 6.0 language so that they could be visualized on screen and easily confirmed. Results: We could develop the program used in calculating and estimating anamorphic prisms used to construct an anamorphoser. Conclusions: Judging from the results of applying this developed program to actual business, we could conclude that this program is useful in calculation and production of anamorphic prisms which are used as components of an anamorphoser because this program can offer a lot of accuracy and quickness to producers.

• Journal of The Korean Association of Information Education
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• v.23 no.5
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• pp.441-449
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• 2019

With the introduction of the 2015 revised curriculum, software education became mandatory in elementary school. The practical subject in the content for the software education consists of information ethics, algorithms, programming, and computer science. Especially, elementary school encourages the unplugged activities. Unplugged activities are preferred among the teachers in the education field as a teaching-learning method. However, those teachers pointed out that the lack of suitable unplugged activity materials was the biggest challenge. In addition, it was pointed out that the existing materials were not suitable for achievement standards, and there are many simple playing-oriented educations that are not linked to computing activities. In this study, we developed an unplugged activity-oriented robot that can be used for the elementary students to learn the basic control structure suggested in the achievement criteria SW education and to develop creative problem solving ability through various activities using sensors. The effectiveness was verified through the software class using the developed robot in this study.

• Journal of Convergence for Information Technology
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• v.11 no.12
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• pp.90-96
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• 2021

In this paper, we designed manufactured and design an integrated interface control unit that has compatibility with brightness control unit, color control unit, and existing control unit. As the implementation method the standard of DVI/HDMI transmission method is applied to the data transmission method, and the Sil 1169 IC is used as the applied IC. Brightness control is programmed to have eight levels of brightness control using the AT89C2051. Also, EPM240T100C5 IC was used for image and dimming data processing. As a result, it is compatible with the control unit using the DVI/HDMI transmission method manufactured by each company and can reproduce clear high quality full HD video according to the surrounding brightness through the full color LED display system.

• Journal of The Korean Association of Information Education
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• v.23 no.1
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• pp.39-53
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• 2019

In the era of the Fourth Industrial Revolution, improving computational thinking to solve problems by smoothly operating and utilizing software. Therefore, the ministry of education has introduced systematic SW education into public education as a revised 2015 curriculum with the aim of raising computational thinking. In order for SW education to be systematically stabilized at the school site, the teaching ability of the teacher must be supported above all. For this purpose, the government is promoting 'SWEET' for improvement of the elementary pre-service teachers' SW education program. However, even if the policy is pursued, there is a tendency to take measures to improve the teaching and learning methods in the field later, and since the subject of change in education is the teacher, it is necessary to grasp the reco-gnition, experience of teachers. This study analyzed qualitatively perception and experience of elementary pre-service teachers about SW education and suggested design guidelines for pre-service teacher training such as providing various learning examples.

• The Journal of Korean Association of Computer Education
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• v.21 no.6
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• pp.15-26
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• 2018

This study aims to examine whether software education has effects on improving creative competency. To this end, the study designed software education lessons to strengthen creative competency for 15 weeks and developed assessment tools. Based on the designed lessons, the 15-week lessons were provided for university students, including a pre-test in the first week and a post-test in the 15th week. The result showed that there was a significant difference in the effects of the lessons, with the mean value of creative competency 0.31 point higher and p-value of 0.002 in the post-test than in the pre-test. The sub-factors of creative competency, including flexibility, originality, openness, and creative implementing skills showed significant differences with p-value all lower than 0.05.

• The Journal of Korean Association of Computer Education
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• v.21 no.6
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• pp.39-47
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• 2018

This paper dealt with investigating the number of minimal spanning ladders originated from ladder game and their properties as well as the related computational thinking aspects. The author modified the filtering techniques to enhance Mathematica project where a new type of graph was generated based on the algorithm using a generator of firstly found minimal spanning graph by repeatedly applying independent ladder operator to a subsequence of ladder sequence. The newly produced YC graphs had recursive and hierarchical graph structures and showed the properties of edge-symmetric. As the computational complexity increased the author divided the whole search space into the each floor of the newly generated minimal spanning graphs for the (5, 10) YC graph and the higher (6, 15) YC graph. It turned out that the computational thinking capabilities such as data visualization, abstraction, and parallel computing with Mathematica contributed to enumerating the new YC graphs in order to investigate their structures and properties.

• Journal of The Korean Association of Information Education
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• v.25 no.2
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• pp.317-325
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• 2021

In this paper, the degree of reflection of SW·AI elements and CT elements was investigated and analyzed for a total of 44 textbooks of Korean, social, moral, mathematics and science textbooks based on the 2015 revised curriculum. As a result of the analysis, most of the activities of data collection, data analysis, and data presentation, which are ICT elements, were not reflected, and algorithm and programming elements were not reflected among SW·AI content elements, and there were no abstraction, automation, and generalization elements among CT elements. Therefore, in order to effectively implement SW·AI convergence education in elementary school subjects, we will expand ICT utilization activities to SW·AI utilization activities. Training on the understanding of SW·AI convergence education and improvement of teaching and learning methods using SW·AI is needed for teachers. In addition, it is necessary to establish an information curriculum and secure separate class hours for substantial SW·AI education.