• Journal of the Korean Data and Information Science Society
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• v.27 no.2
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• pp.315-325
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• 2016

Thanks to the advantages of low cost and quick results, public opinion polls on election in Korea have been generally conducted by telephone survey, even though it has critical disadvantage of low response rate. In public opinion polls on election in Korea, the general method to handle nonresponses is adjusting the survey weight to estimate parameters. This study first drives mathematical expression of estimator and its bias with variance estimators with/without nonresponses in election polls in Korea. We also investigates the nonresponse rate of telephone survey on 2012 Korea presidential election. The average response rate was barely about 14.4%. In addition, we conducted a survey in April 2014 on the respondents's attitude toward telephone surveys. In the survey, the first reason for which respondents do not answer on public opinion polls on election was "feel bothered". And the aged 20s group, the most low response group, also gave the same answer. We here suggest that survey researchers motivate survey respondents, specially younger group, to participate surveys and find methods boosting response rate such as giving incentive.

• Journal of the Korean School Mathematics Society
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• v.16 no.4
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• pp.745-770
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• 2013

In the knowledge-based society today, most knowledge is the integrated one which is difficult to be classified into subjects rather than the knowledge of a single subject. Thus, integrated thinking, which integrated knowledge is preferentially acquired first and then can be also associated with imagination and artistic sensitivity, is simultaneously required in order that we have a problem-solving capability in our daily life. STEAM education(science, technology, engineering, arts and mathematics) is one of the educational methods to improve this problem-solving capability as well as integrated thinking. This research developed materials for STEAM education which can be applied to the 6th grade curriculum of elementary school mathematics, then input it, and analyzed how it impacts with students' attitudes toward mathematics. Unit 3 'Prism' and Pyramid' were restructured and replaced by classes such as 'Spaghetti Project' or 'Paper Craft'. Unit 4 'Several Solid Figure' was taught as a class of 'EDUCUBE'. Unit 6 'Proportional Graph' was taught as a class of 'Creating my own bracelet'. After having this class, we found that mathematics class applied STEAM also has a positive effect on the mathematical attitude of students. Many students said that math is fun and gets more interesting after having math class applied STEAM and we come to know that they have positive awareness of mathematics.

• Communications of Mathematical Education
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• v.26 no.3
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• pp.251-271
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• 2012

The purpose of this study is: 1) to determine error sources and the effects of each error source, 2) to investigate optimal measuring conditions from holistic and analytic scoring methods, and 3) to compare the value of reliability between Cronbach's alpha and the generalizability coefficient in self-introduction letter and teacher's recommendation letter based on the generalizability theory in identification of mathematical gifted students by observations and nominations. Data of this study were collected from the science education institute for the gifted attached to the university located within in a capital city for the 2011 academic year. Scores form two raters using holistic and analytic scoring methods in both assessment types were used. The results of this study were as follows. First, as to both assessment types, error sources for people were relatively large regardless of scoring methods. However, error sources for raters in holistic scoring methods had a more significant impact than those of analytic scoring methods. Second, to set optimal measuring conditions in the self-introduction letter and teacher's recommendation letter, if we fixed the number of raters into 2 based on holistic scoring methods, at least 5 and 10 content domains were needed, respectively. In addition, the number of items in teacher's recommendation letter should be more than 3 when we fixed the number of content domains into 4, and the number of items in self-introduction letter should be more than 8 when we fixed the number of content domains into 6 using analytic scoring methods. Third, Cronbach's alpha having only a single source of errors was higher than the generalizability coefficient regardless of assessment types and scoring methods. Hence we recommend that generalizability coefficient based on various error sources such as raters, content domains, and items should be considered to keep a satisfactory level of reliability in both assessment types.

• Communications of Mathematical Education
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• v.29 no.3
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• pp.423-439
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• 2015

This study examines the relationship between prior learning experience, the high school records, mathematics grade in the KSAT(Korean Scholastic Aptitude Test) and mathematics achievement, GPA(grade point average) of college freshmen. It analyses how much mathematics capacities in the time of high school affect mathematics achievement of college freshmen. This study surveyed 193 freshmen, attending in a college of science and engineering, taking the 'basic differential and integral calculus' lecture, which was opened for the first semester of 2014 in the A university. The data processing was fulfilled by means of technical statistics, correlation analysis, difference test, ANOVA, ex post facto test, and regression analysis. The outcomes of this survey are followings: Firstly, over 90 percent of college freshmen underwent prior learning of mathematics when they attended high school. Secondly, their perception of effectiveness for prior learning is founded to be meaningfully lower than their perception of its needfulness. Thirdly, while there is higher positive correlation between mathematics achievement and GPA in the college, there is little correlation between high school records and GPA in the college. Also, there is little correlation between mathematics grade in the KSAT and mathematics achievement in the college. Fourthly, the accomplishments in the high school(The high school records, mathematics grade in the KSAT) and the efforts, satisfaction, necessity, etc. for prior learning had little effect on academic achievement in college mathematics. Based on these results, this study makes some suggestions for developing academical achievement in college mathematics.

• Education of Primary School Mathematics
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• v.25 no.4
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• pp.411-431
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• 2022

In this paper, implications for future curriculum compilation were sought by analyzing the process and results of compiling books for elementary school mathematics textbooks government published according to the 2015 revised curriculum. The 2015 revised elementary mathematics textbooks government published was operated with a systematic compilation system so that academia and school field experts across the country could demonstrate their expertise. As improvements in content, the unit and time to strengthen basic computational skills were increased, and the mathematical concept and principle introduction method and algorithm presentation method were improved, and the internal connection between contents was strengthened. The learning period was adjusted, such as moving and arranging contents that are difficult for students to understand to the upper semester or the upper grade. In the 1st and 2nd graders, the amount of reading was drastically reduced to suit the students' level of Korean, and sentences and vocabulary were improved, and instructions were briefly revised. As for editing and design improvements, illustrations of each unit's introduction and contextual pictures were presented in detail, and the characters in the textbook were consistently presented across all grades, giving children characters a role to actively participate in learning in the textbook. In the process of compiling, the media, the National Assembly, and civic groups raised opinions that sentences and vocabulary in first-year textbooks are more difficult than students' level of Hangeul education, that reducing textbooks makes it difficult for students to understand. Accordingly, efforts to improve textbook compilation and the results were viewed. Through the overall analysis as above, for future compilation of state-authored textbooks and certified textbooks, a plan to improve textbook compilation for students and teachers and a plan to operate compilation was proposed.

• Journal of Biomedical Engineering Research
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• v.28 no.3
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• pp.348-354
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• 2007

Polymer actuators, which are also called as smart materials, change their shapes when electrical, chemical, thermal, or magnetic energy is applied to them and are useful in wide variety of applications such as microelectromechanical systems (MEMS), machine components, and artificial muscles. For this study, Polyaniline/carbon-nanotube polymer actuator that is one of electroactive polymer actuators was prepared. Since the nonlinear phenomena of hysteresis and a step response are essential considerations for practical use of polymer actuators, we have investigated the movement of the Polyaniline/carbon-nanotube polymer actuator and have developed an integrated model that can be used for simulating and predicting the hysteresis and a step response during actuation. The Preisach hysteresis model, one of the most popular phenomenological models of hysteresis, were used for describing the hysteretic behavior of Polyaniline/carbon-nanotube polymer actuator while the ARX method, one of system identification techniques, were used for modeling a step response. In this paper, we first expain details in preparation of the Polyaniline/carbon-nanotube polymer then present the mathematical description of our model, the extraction of the parameters, simulation results from the model, and finally a comparison with measured data.

• Journal of Korean Society for Geospatial Information Science
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• v.21 no.3
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• pp.55-62
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• 2013

This paper aims to detect Speed Bump by using Omni-directional Camera and to suggest Real-time update scheme of Speed Bump through Vision Based Approach. In order to detect Speed Bump from sequence of camera images, noise should be removed as well as spot estimated as shape and pattern for speed bump should be detected first. Now that speed bump has a regular form of white and yellow area, we extracted speed bump on the road by applying erosion and dilation morphological operations and by using the HSV color model. By collecting huge panoramic images from the camera, we are able to detect the target object and to calculate the distance through GPS log data. Last but not least, we evaluated accuracy of obtained result and detection algorithm by implementing SLAMS (Simultaneous Localization and Mapping system).

• Journal of Biomedical Engineering Research
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• v.44 no.5
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• pp.303-314
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• 2023

This study aimed to assess the practical feasibility of advanced deformable image registration (DIR) algorithms in radiotherapy by employing two distinct datasets. The first dataset included 14 4D lung CT scans and 31 head and neck CT scans. In the 4D lung CT dataset, we employed the DIR algorithm to register organs at risk and tumors based on respiratory phases. The second dataset comprised pre-, mid-, and post-treatment CT images of the head and neck region, along with organ at risk and tumor delineations. These images underwent registration using the DIR algorithm, and Dice similarity coefficients (DSCs) were compared. In the 4D lung CT dataset, registration accuracy was evaluated for the spinal cord, lung, lung nodules, esophagus, and tumors. The average DSCs for the non-learning-based SyN and NiftyReg algorithms were 0.92±0.07 and 0.88±0.09, respectively. Deep learning methods, namely Voxelmorph, Cyclemorph, and Transmorph, achieved average DSCs of 0.90±0.07, 0.91±0.04, and 0.89±0.05, respectively. For the head and neck CT dataset, the average DSCs for SyN and NiftyReg were 0.82±0.04 and 0.79±0.05, respectively, while Voxelmorph, Cyclemorph, and Transmorph showed average DSCs of 0.80±0.08, 0.78±0.11, and 0.78±0.09, respectively. Additionally, the deep learning DIR algorithms demonstrated faster transformation times compared to other models, including commercial and conventional mathematical algorithms (Voxelmorph: 0.36 sec/images, Cyclemorph: 0.3 sec/images, Transmorph: 5.1 sec/images, SyN: 140 sec/images, NiftyReg: 40.2 sec/images). In conclusion, this study highlights the varying clinical applicability of deep learning-based DIR methods in different anatomical regions. While challenges were encountered in head and neck CT registrations, 4D lung CT registrations exhibited favorable results, indicating the potential for clinical implementation. Further research and development in DIR algorithms tailored to specific anatomical regions are warranted to improve the overall clinical utility of these methods.

• Communications of Mathematical Education
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• v.30 no.1
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• pp.67-83
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• 2016

Correcting an imbalance between cognitive and affective aspects of mathematics in schools is recognized as a crucial issue with regards to mathematics education in Korea. Therefore, research and studies about affective aspects have been increasing and themes relating to affective aspects were diverse. Their theme included the improvement of affective aspect, investigation of factors of affective aspect, and development of measurement tools for affective aspect. The purpose of this study is to analyze and organize the research that has been done with respect to affective aspect and drive trend, implication, and their instruction to mathematics education. This study has investigated 103 studies released from 2005 to 2015 on KCI, Korea Citation Index. The results of this study are as follow. First, since released research of affective aspects in mathematics has not increased in number in the last 11 years, academic interest in the affective aspects seems lower than recent interest arousing in Korea. Second, most studies utilized quantitative research as a tool to analyze phenomena and the cause and effect of affective aspects. Third, middle school students were the most common subjects of the studies, followed by elementary school students. Fourth, the studies had various themes such as analyzing the cause and effect of affective aspect, recognizing changes of affective aspects, and measuring affective aspects. The studies, especially, focused most on analyzing how to improve affective aspects by applying it to programs such as mathematic activities and solving mathematic problems. It is necessary for future research to have a long-term perspective and to provide a space for communication. Research should not only focus on how recognize affective aspects differently, which is based on its cultural background, but also to draw affective solutions from them.

• Culinary science and hospitality research
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• v.23 no.5
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• pp.58-66
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• 2017

The purpose of this study was to assess priority of educational needs for the development of curriculum based on key competencies of NCS for departments related to culinary arts in a 2-year college. In order to achieve this objective, the survey has been distributed to cooks working in hotel restaurants or restaurant companies by social network service and a total of 360 responses were analyzed excluding 18 responses. The collected surveys were analysed by using paired t-test, Borich's needs analysis and the locus for focus analysis. The results of this study were as follows. First, the difference between the level of importance and present level about key competencies recognized by cooks working in restaurant company was statistically significant in 9 fields of key competencies excluding mathematical competence. The difference recognized by cooks working in hotel was statistically significant in all 10 fields of key competencies. Second, the results of Borich's needs assessment showed that the education needs of problem solving competence were the highest, followed by interpersonal, resource management, communication, information competence. Finally, considering both Borich's needs assessment and the locus for focus analysis, cooks working in hotel restaurants recognized that educational needs of communication, interpersonal, problem-solving, information competence were the top priority, and cooks working in restaurant companies recognized that educational needs of communication, interpersonal, skill, resource management competence were the top priority. Therefore, it is necessary to develop curriculum for culinary arts specialists based on key competence of top priority.