• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.2
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• pp.157-167
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• 2010

Unscented Kalman filter based backward filter is derived and the positions from extended Kalman filter, unscented Kalman filter, and extended Kalman smoother are compared and analyzed through a simulation test. Considering the poor GPS signal reception, the simulation is performed under the assumption of only the start and end points of the trajectory, composed of 4 curves and 5 straight sections in the area of $40m{\times}40m $, are known. The test shows that the smoothers generate much better positioning results of 8~9m improvement compared to those from the forward filters. For the comparison between the smoothers, the analysis is performed separately for the curves and straight segments. In both cases, the unscented Kalman smoother generates better positioning error; 10cm and 23cm improved positioning results in straight segment and curves, respectively.

• Journal of the Korean Society for information Management
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• v.29 no.4
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• pp.101-121
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• 2012

Since IR systems which adopt only Boolean IR model can not provide ranked search result, users have to conduct time-consuming checking process for huge result sets one by one. This study proposes a method to provide search results ranked by using coupling information between tags instead of index weight information in Boolean IR model. Because document queries are used instead of general user queries in the proposed method, key tags used as queries in a relevant document are extracted. A variety of groups of Boolean queries based on tag couplings are created in the process of extracting queries. Ranked search result can be extracted through the process of matching conducted with differential information among the query groups and tag significance information. To prove the usability of the proposed method, the experiment was conducted to find research trend analysis information on selected research information. Aslo, the service based on the proposed methods was provided to get user feedback for a year. The result showed high user satisfaction.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.1
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• pp.165-170
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• 2015

The unsharp mask technique emphasize the boundary of the image by adding the boundary of the original image. This technique improves quality by emphasize its boundaries but produce rough image from image noise. The multi channel unsharp mask is possible to enhance entire contrast of the image by applying at least two channels of unsharp mask. However, There is limitations to strengthen boundaries even if the scale strongly applies the multi channel unsharp mask technique. To solve this problem, linear scaling to nonlinear scaling by applying exponential function to existing multi channel unsharp mask technique. Experimental results show enhanced contrast for desired area because of control scaling in details compared with existing unsharp mask technique.

• Journal of the Korean Society for information Management
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• v.18 no.3
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• pp.29-40
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• 2001

In this paper, we suggest a query optimization algorithm to select the optimal processing method of an extended boolean query on inverted files. There can be a lot of methods for processing an extended boolean query according to the processing sequence oh the keywords con tamed in the query, In this sense, the problem of optimizing an extended boolean query it essentially that of optimizing the keyword sequence in the query. In this paper, we show that the problem is basically analogous to the problem of finding the optimal join order in database query optimization, and apply the ideas in the area to the problem solving. We establish the cost model for processing an extended boolean query and develop an algorithm to filled the optimal keyword-processing sequence based on the concept of keyword rank using the keyword selectivity and the access costs of inverted file. We prove that the method selected by the optimization algorithm is really optimum, and show, through experiments, that the optimal method is superior to the others in performance We believe that the suggested optimization algorithm will contribute to the significant enhancement of the information retrieval performance.

• Journal of the Korea Society of Computer and Information
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• v.17 no.9
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• pp.189-196
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• 2012

The purpose of this research is to compare the effect of unplugged learning method with traditional lecture method on intellectual disability students' informatics education achievement. For this goal, we developed a new unplugged learning method and new appropriate teach-learning materials that can improve the intellectual disability students' informatics education achievement. We randomly divided special school specialized course freshman into the experimental group and the control group. We applied unplugged learning method to the experimental group and lecture teaching method to the control group. According to these results, Intellectual disability students participated in task interestingly and spontaneously. It has been proved that the teaching-learning materials applied unplugged learning method were helpful for intellectual disability students' informatics education achievement.

• Journal of The Korean Association of Information Education
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• v.16 no.3
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• pp.291-298
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• 2012

The use of Unplugged Classes to easily teach the contents of Computer Science has recently become increasingly widespread. However, there has been a lack of research to discover which learner groups would benefit most from this method. Therefore, the intention of this research is to analyze learner's traits by examining score levels of post-class assessments made after Unplugged Classes. For this research, the learner's trait data has been divided into two groups: students' propensity towards computer comprehension and students' natural disposition. In addition to the verification of the relation between a learner's accomplishment level and the aforementioned data groups, meaningful applications of the data will also be recognized for practical use in elementary school classrooms. The results of this research will be valuable for elementary school teachers who utilize the Unplugged Class.

• Journal of The Korean Association of Information Education
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• v.22 no.1
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• pp.103-111
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• 2018

In order to examine the educational effects and future directions of unplugged activities, we conducted a systematic review of Korean journals and theses from 2007 to 2016. Three kinds of database were used for systematic review: RISS, KISS, and E-article, and were performed searches using options such as 'unplugged' and 'play-centered'. Based on the protocol selected in the framework of the systematic review, 37 articles were selected analyzed in terms of research status, research subjects, research methods, research hubs, study mechanisms, educational methods, and research effects. Unplugged activities were the most popular among elementary school students. Educational effects were found to have significant effects on academic achievement, problem solving ability, and logical thinking ability. In the affirmative domain, there was a significant effect on interest, curiosity, and motivation. Based on the results of the analysis, the characteristics and implications of Unplugged activities and present the direction of future education were discussed.

• Journal of The Korean Association of Information Education
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• v.23 no.6
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• pp.621-628
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• 2019

The 2015 revised curriculum offers elementary students an unplugged computing education as a way to learn the concepts and principles of computer science in an easy and fun way and to improve their computational thinking. Yutnori is a traditional board game unique to Korea, which contains various contents such as history, culture, and science of our people, which helps to cultivate cultural identity of learners, and can effectively promote cooperation and communication among members. In this paper, we examined the possibility that Yutnori could be used as an unplugged computing tool in elementary school software education and convergence education. Korean traditional board game Yutnori has elements that can learn the sun and movements of heavenly bodies as well as sequential, selection, and repetitive algorithm elements. Unplugged activities that apply Korean traditional culture Yutnori is expected to help foster creative convergence talents by improving elementary school students' computational thinking, communication and community.

• The Journal of Korean Association of Computer Education
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• v.22 no.4
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• pp.21-34
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• 2019

SW education is being implemented in all the school due to the application of the 2015 Curriculum. The purpose of SW education is to improve Computational Thinking by using Unplugged Activities, Educational Programming Language, and Physical Computing. Among them, 73 domestic and 85 overseas researches related to 'Unplugged Activities' were compared and analyzed using semantic network analysis techniques. As a result, the research on 'Unplugged Activities' has been started from 1998, and the research has started in Korea since 2006. As the CT is recognized as a core competence for the future society in line with the 4th Industrial Revolution, researches have been rapidly increasing in both the domestic and overseas countries since 2016. In Korean studies, it was analyzed that many main words related to the elemental factors such as 'unplugged activity', 'robot utilization', 'educational programming language' were found. This suggests that future research should move toward research for the promotion of 'CT' which is the purpose of computer science.

• The Journal of the Convergence on Culture Technology
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• v.5 no.1
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• pp.297-303
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• 2019

This study aims to investigate the characteristics, concepts, types, and strategies of unplugged coding for young children based on computing thinking. The key to unplugged coding for young children is computing thinking. Unplugged coding based on computing thinking for young children can be used to solve problems that can be encountered in everyday life through playing games based on logical thinking by positively utilizing algorithm boards, s-blocks, coding robots, and smart devices without using programs And find new ways to play. Types of unplugged coding for young children include direct input to smart devices, using coding robots with dedicated apps, practicing coding procedures using algorithms, and using hybrid methods. Strategies include understanding algorithms, drawing flowcharts, dividing into smaller parts, finding patterns, inserting, and predicting outcomes.