• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.2
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• pp.56-64
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• 2018

In recent years, imbalanced data is one of the most important and frequent issue for quality control in industrial field. As an example, defect rate has been drastically reduced thanks to highly developed technology and quality management, so that only few defective data can be obtained from production process. Therefore, quality classification should be performed under the condition that one class (defective dataset) is even smaller than the other class (good dataset). However, traditional multi-class classification methods are not appropriate to deal with such an imbalanced dataset, since they classify data from the difference between one class and the others that can hardly be found in imbalanced datasets. Thus, one-class classification that thoroughly learns patterns of target class is more suitable for imbalanced dataset since it only focuses on data in a target class. So far, several one-class classification methods such as one-class support vector machine, neural network and decision tree there have been suggested. One-class support vector machine and neural network can guarantee good classification rate, and decision tree can provide a set of rules that can be clearly interpreted. However, the classifiers obtained from the former two methods consist of complex mathematical functions and cannot be easily understood by users. In case of decision tree, the criterion for rule generation is ambiguous. Therefore, as an alternative, a new one-class classifier using hyper-rectangles was proposed, which performs precise classification compared to other methods and generates rules clearly understood by users as well. In this paper, we suggest an approach for improving the limitations of those previous one-class classification algorithms. Specifically, the suggested approach produces more improved one-class classifier using hyper-rectangles generated by using Gaussian function. The performance of the suggested algorithm is verified by a numerical experiment, which uses several datasets in UCI machine learning repository.

• Imaging Science in Dentistry
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• v.48 no.3
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• pp.185-190
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• 2018

Purpose: The aim of this study was to compare the location and the shape of the mandibular lingula in skeletal class I and III patients using panoramic radiography and cone-beam computed tomography. Materials and Methods: The sample group included 190 skeletal class I patients and 157 class III patients. The location of the lingula in relation to the deepest point of the coronoid notch was classified into 3 types using panoramic radiographs. The shapes of the lingulae were classified into nodular, triangular, truncated, or assimilated types using cone-beam computed tomographic images. The data were analyzed using the chi-square test. Results: The tips of the lingulae were at the same level as the coronoid notch in 75.3% of skeletal class I patients and above the coronoid notch in 66.6% of class III patients. The positions of the lingulae in relation to the deepest point of the coronoid notch showed statistically significant differences between class I and class III patients. The most common shape was nodular, and the least common was the assimilated shape. Although this trend was not statistically significant, the triangular shape was more frequently observed in class III patients than in class I patients. Conclusion: The locations and the shapes of the mandibular lingulae were variable. Most of the lingulae were at the same level as the coronoid notch in skeletal class I patients and above the coronoid notch in skeletal class III patients. The nodular and assimilated-shaped lingulae were the most and the least prevalent, respectively.

• Journal of the Korean School Mathematics Society
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• v.4 no.2
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• pp.135-142
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• 2001

The selected questions for this study was their conversation in problem solving way of working together. To achieve its purpose researcher I chose more detail questions for this study as follows. $\circled1$ What is the difference of strategy according to its level \ulcorner $\circled2$ What is the mathematical ability difference in problem solving process concerning its level \ulcorner This is the result of the study $\circled1$ Difference in the strategy of each class of students. High class-high class students found rules with trial and error strategy, simplified them and restated them in uncertain framed problems, and write a formula with recalling their theorem and definition and solved them. High class-middle class students' knowledge and understanding of the problem, yet middle class students tended to rely on high class students' problem solving ability, using trial and error strategy. However, middle class-middle class students had difficulties in finding rules to solve the problem and relied upon guessing the answers through illogical way instead of using the strategy of writing a formula. $\circled2$ Mathematical ability difference in problem solving process of each class. There was not much difference between high class-high class and high class-middle class, but with middle class-middle class was very distinctive. High class-high class students were quick in understanding and they chose the right strategy to solve the problem High class-middle class students tried to solve the problem based upon the high class students' ideas and were better than middle class-middle class students in calculating ability to solve the problem. High class-high class students took the process of resection to make the answer, but high class-middle class students relied on high class students' guessing to reconsider other ways of problem-solving. Middle class-middle class students made variables, without knowing how to use them, and solved the problem illogically. Also the accuracy was relatively low and they had difficulties in understanding the definition.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.12
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• pp.9-24
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• 1995

In this paper, we proposed and analysed two kinds of priority control mechanism to archive the cell loss rate requirement and the delay requirement of each class. The service classes of our concern are the high time priority class(class 1) and the high loss priority class(class 2). Two kinds of priority control mechanism is divided by the method of storing the arriving class 2 cell in buffer on case of buffer full. The first one is the method which discarding the arriving class 2 cell, the second one is the mothod which storing the arriving class 2 cell on behalf of pushing out the class 1 cell in buffer. In the proposed priority schemes, one cell of the class 1 is transmitted whenever the maximum K cells of the class 2 is transmitted on case of transmitting the class 1 cell and the class 2 cell sequentially. In this paper, we analysed the cell loss rate and the mean cell delay for each class of the proposed priority scheme by using the Markov chain. The analytical results show that the characteristic of the mean cell delay becomes better for the class 1 cell and that of the cell loss rate becomes better for the class 2 cell by selecting properly the cell transfer ratio according to the condition of input traffic.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.3
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• pp.133-139
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• 2003

In this paper, a new control scheme of Class-E inverter for Induction Heating (IH) Jar applications with clamped voltage characteristics using Pulse-Frequency-Modulation (PFM) is introduced. To reduce the voltage stress of switch, the proposed PFM control scheme doesn't need any auxiliary circuit in comparison to a family of Active Clamped Class-E (ACCE) inverter. It can decrease voltage stress of switch through modulation of switching frequency. The Class-E inverter using the proposed control scheme has the advantage of not only the same output power when it is compared with a Hybrid-Active Clamped Class-E (Hybrid-ACCE) inverter but also Zero-Voltage-Switching (ZVS), which are characteristics of conventional Class-E and ACCE inverter. The control principles and analysis of proposed method are explained in detail and its validity is verified through simulation and experimental results.

• Educational Technology International
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• v.19 no.2
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• pp.175-197
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• 2018

Flipped classroom (FC) has gained attention as an active learning approach. Designing effective out-of-class activities to help prepare students for in-class activities is fundamental for successful implementation of FC. This study investigated the effectiveness of Goal-Based Scenarios (GBS) for out-of-class learning in FC. Four out of twelve units in a medical humanities course for Year 2 medical students was redesigned into a FC format, where e-learning modules were designed using a GBS approach for out-of-class activities and classroom debates were implemented for in-class activities. The other eight units were delivered in a conventional classroom debate format, which included reading text materials as pre-class assignments. A formative evaluation study was conducted using questionnaires and interview methods and students' academic achievements were evaluated by comparing their pre- and post-test scores between FC and conventional units. Students had positive perceptions of the e-learning modules in GBS approach and preferred the structure of learning in the FC format. Students' pre-test scores were slightly higher in the FC units, yet their post-test scores were comparable with conventional units. This study illustrates students' perceptions that the learning was bettered structured in FC and that the out-of-class learning using the GBS approach helped them better prepared for in-class activities.

• Journal of the Korea Fashion and Costume Design Association
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• v.25 no.3
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• pp.41-52
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• 2023

This study developed and taught VR content to be used in clothing design and composition practice, which are practical subjects for home education students at the College of Education, and examined the learning effects on students who participated in VR experiences. First, after experiencing classes using VR content, students' perceptions of classes were examined considering participation, class level, expectations, and satisfaction through a survey. As a result of examining the experience of learning sewing machines in classes using VR content and changes in perception of classes, it was found that the class level, class expectations, and satisfaction were affected. As a result of comparative analysis of VR experiences and the perception of VR classes prior to experiencing VR content related to sewing machines developed for practical subjects, VR experiences affected class participation, class level, expectations, but satisfaction was not affected. The advantages of the VR class that students mentioned in the subjective evaluation included interest in the class, the degree of participation, the VR experience, and the use of VR. As for the disadvantages, difficulties in using the device, dizziness, frustration when using the device, and limitations of the program were mentioned.

• Journal of Korea Game Society
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• v.15 no.3
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• pp.79-86
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• 2015

Effective feedback plays a key role in education environments to motivate the students and to maintain their flow. However, there usually lacks in providing effective feedbacks in education environments due to an excessive number of students and insufficient class times. The purpose of this paper is to analyze the educatees' response on game like feedback using App. In this paper, Class123 App developed and published by BravePops was used. During one semester, Class123 App had been used in engineering class and the educatees' responses on game like feedbacks using Class123 App are analyzed. Statistical analysis results show that the feedbacks using Class123 App made positive effects to motivate the students. Especially, the positive feedbacks were more effective than the negative feedbacks.

• Journal of the Korean Society of Earth Science Education
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• v.8 no.2
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• pp.218-226
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• 2015

This study is to find out that the effect of science class applied Jigsaw cooperative learning to study achievement and Creative personality. The class section of this study is 5th grade 1 semester of science 2 chapters, 'the solar system and the stars' This study has been aimed at 2 class 40 students of 5th grade in D metropolitan city G elementary school in 2015, one class 20 students are the research group to apply science class using a Jigsaw cooperative learning techniques, another class 20 students were comparison groups to apply general science classes. Research result and conclusion obtained through the discussion are as follows. First, science class using Jigsaw cooperative learning technique was not effective. Even though the science class with jigsaw cooperation education could not achieve the beneficial academic achievement, which is the cognition factor, when it comes to precedent study, the definition factors such as teamwork, consideration and readership show great effects. Second, science class using Jigsaw cooperative learning technique was effective in cultivating creative personality. This can be interpreted that the science class applied the jigsaw cooperation study help the creativity development. Third, after the science class applied jigsaw cooperation study, the students' perceptions also have changed in positive way. They were tend to care each other and cooperate with others. That means the class is good way to cultivate collective intelligence, which is a virtue of community.

• Korean Journal of Community Nutrition
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• v.9 no.3
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• pp.326-332
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• 2004

The research objective was to identify the effect of various instruction media on improving students' foodservice management competencies and for increasing class satisfaction. The research involved a comparison of two student groups. One group consisted of students who attended a lecture-based food purchasing class (Group A). The other group was students who attended the same class, and who also used various media as well as receiving the lecture (Group B). The results were as follows: 1) After a 16 week program, Group B perceived their procurement management competencies to be higher than those of Group A, especially in setting up purchasing goals, marketing research, and using computer systems for procurement; 2) In terms of class satisfaction, it was also observed that Group B was more satisfied with food purchasing class than was Group A. Group B gave high scores, especially in effective utilization of media, increasing motivation, and understanding; 3) Group B perceived that various instruction media was helpful for developing their procurement management competencies. Respondents evaluated the usefulness of media in the following order: using Power Point watching videos, visiting web-sites for food purchasing class, and surfing the World Wide Web. The results of the research show that using various instruction media for food purchasing classes would improve students' foodservice management competencies. Therefore, instructors who teach foodservice management related courses should consider developing teaching strategies that apply various instruction media for students to enhance their foodservice management competencies and to increase class satisfaction.