• Journal of the Korea Safety Management & Science
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• v.11 no.1
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• pp.87-91
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• 2009

본 논문은 상대적으로 새로운 기법인 Parzen Density Estimation과 Multi-class SVM을 이용한 지능형 고장 탐색과 진단 방법을 제안하고 있다. 본 연구에서는 롤링 베어링을 대상으로 고장을 탐색하고 진단하기 위한 방법을 제안하는데 Parzen Density Estimation과 Multi-class SVM은 고장 클래스를 잘 표현할 수 있다. Parzen Density Estimation은 새로운 패턴 데이터의 거절과 알려진 데이터 패턴의 밀도의 평가에 의해 새로운 패턴을 찾아낼 수 있고, Multi-class SVM 기반의 방법은 여러 클래스의 고장을 support vector로 표현하여 고장 패턴을 찾아낼 수 있다. 본 연구에서는 실제의 다중 클래스를 가지는 롤링 베어링의 고장 데이터를 사용하여 고장 패턴을 탐색하는 과정을 보여주는데, 커널함수의 적절한 파라미터의 선택에 의한 Multi-class SVM 기반의 방법이 multi-layer perceptron이나 Parzen Density Estimation 방법보다 우수함을 입증한다.

• Journal of Korean Physical Therapy Science
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• v.30 no.3
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• pp.84-90
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• 2023

Background: This study aimed to investigate the effects of flipped learning education on academic motivation and class satisfaction in physical therapy students. Design: Cross-sectional study. Methods: Participants included 72 physical therapy students (experimental group=36, control group=36). In order to compare the effects of flipped learning education, flipped learning and lecture-style learning were provided in a class titled Acticities of Daily Living and Practice. An independent t-test was used to compare academic motivation and class satisfaction between two groups. Results: The flipped learning group showed a significantly higher level of academic motivation and class satisfaction compared to the traditional learning group (p<0.05). Conclusion: These results showed that flipped learning education is an effective learning strategy for improving the academic motivation and class satisfaction of physical therapy students.

• Bulletin of the Korean Mathematical Society
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• v.56 no.2
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• pp.373-382
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• 2019

In this note, we mainly discuss strongly Gorenstein hereditary rings. We prove that for any ring, the class of SG-projective modules and the class of G-projective modules coincide if and only if the class of SG-projective modules is closed under extension. From this we get that a ring is an SG-hereditary ring if and only if every ideal is G-projective and the class of SG-projective modules is closed under extension. We also give some examples of domains whose ideals are SG-projective.

• Journal of the Korean Society of Earth Science Education
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• v.5 no.1
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• pp.105-113
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• 2012

The purpose of this study was to examine the effects of storytelling skill on science learning motivation and space perception ability. For this study the 5 grade, 2 class was divided into a research group and a comparative group. The class was pre-tested in order to ensure the same standard. The research group had the science class with storytelling skill, and the comparative group had the class with teacher centered lectures for 10 classes in 10 weeks. The storytelling skill was focused on finding stories, constellation searching, story deciding, story hero deciding, story composition, storytelling completion. To prove the effects of this study, science learning motivation was split up according to attention power, relation, confidence, and sense of satisfaction. Also, space perception ability consisted of two-dimensional rotation, 3 dimension rotations, reflection, three-dimensional searching, number of block, and figure type in pattern. The results of this study are as follows. First, using storytelling skill was effective in science learning motivation. Second, using storytelling skill was effective in space perception ability. Also, after using storytelling skill was good reaction by students. As a result, the elementary science class with storytelling skill had the effects of developing science learning motivation and space perception ability. it means the science class with storytelling skill has potential possibilities and value to develop science learning motivation and space perception ability.

• Journal of Science Education
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• v.45 no.1
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• pp.55-68
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• 2021

The modern society is rapidly changing, and accordingly, the required teacher image is changing as well. Middle school students are immature, when they undergo major changes both physically and mentally, and teachers have a great influence. How students perceive the teacher determines the relationship between teachers and students. Therefore, it is necessary to analyze what kind of teacher image middle school students want. The purpose of this study is to analyze the image of a science teacher who prefers and avoids each class situation perceived by middle school students. To this end, 502 middle school students were divided into five classes: class type, class material presentation method, subject instruction method, subject content explanation method, and class atmosphere, and the image of science teacher who prefers and avoids is described in an open format. Concepts presented by middle school students were analyzed through semantic network analysis (SNA). The conclusions of this study are as follows: first, in order to make middle school students interested in science, an inquiry-centered experiment class should be conducted. Second, the change of class by science teacher can change it into preferred science class. Third, student-centered classes should be conducted according to the level so that students can understand. Finally, science teachers continue to strive through communication between science teachers and students, and students and students, and look forward to changes in science classes through this.

• International Journal of Reliability and Applications
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• v.5 no.4
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• pp.155-162
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• 2004

A new class of life distributions is studied. This class is defined based on comparing the residual life to the whole life in the moment generating function order giving "the new better than used in the moment generating function order ageing class ($NBU_{mgf}$)". Some new results of this class are given including some closere properties and characterizations. Finally testing exponentially against the $NBU_{mgf}$ class is also addressed.

• Journal of the Korean Society of Earth Science Education
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• v.12 no.1
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• pp.54-63
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• 2019

The purpose of this study was to investigate the effect of small group discussion and debate emphasizing maker class on elementary school students's science learning motivation and scientific attitude. The conclusion of the study is as follows. First, it was shown that the small group discussion and debate emphasizing maker class had a statistically significant effect on elementary school students's science learning motivation. This is due to the fact that the small group discussion and debate emphasizing maker class stimulates students' interaction, which is why students are more interested in class while solving problems with their peers. Second, it was found that the small group discussion and debate emphasizing maker class had a statistically significant effect on the elementary school students' scientific attitude. This allows students to have enough opportunity to express their opinions through small group discussions and debate, and I think that because they listen to others' opinions when they make new things or make new plans, so they have been able to increase their scientific attitude continuously. Third, based on the analysis of the participant students' opinions on the small group discussion and debate emphasizing maker class, all the participants answered that they were interested in this kind of class and they want to participate in this kind of maker class again. Therefore, it is thought that the small group discussion and debate emphasizing maker class can play a big role in raising the elementary school students's science learning motivation and scientific attitude.

• Journal of Science Education
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• v.39 no.1
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• pp.58-79
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• 2015

This study is to analyze the 2289 students questionnaires from 3rd to 9th grade students in order to analyze the students' perceptions change aspect by their grade about the frequency and type of students' question during various science class context. After the class contexts proposed in the questionnaire subcategorize into 19 subitems about 4 areas of class content, class pattern, class material and class process, this study examined the frequency and type of students' question during a science class by each item. The results of this study were as follows. First, the type of students' question was that the most frequent was understanding question and the second was memory question and these both types were half frequency. There was no special tendency related the change of students' question type by school year. Second, the frequency of 4th grade students' question was the highest among other school year students and the frequency of students' question was lowered by the higher school year. The change of students' question by school year was the biggest between 3rd and 4th grade. The class strategies for improving the class effect reflect that the various and active students' question by class context and school year stimulates students' thinking and also builds up the active class environment.

• Journal of Gifted/Talented Education
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• v.26 no.1
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• pp.37-51
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• 2016

This study examined the friendship expectation that science-gifted and non-gifted elementary students perceived in gifted class and regular class. In 233 science-gifted elementary students and 329 non-gifted elementary students, we measured the friendship expectation that sub-domains were intimacy, ability similarity, and morality. The results of this study were as follows: First, according to the results of comparing the friendship expectations of science-gifted and non-gifted students at the regular class, there was statistically significant intergroup difference in the sub-domains of intimacy and morality, but there was no significant difference in the sub-domain of ability similarity. Second, according to the results of comparing the friendship expectations of science-gifted at the gifted class and at the regular class, there was statistically significant difference in the sub-domain of intimacy, but there was no significant difference in the sub-domains of morality and ability similarity. Based the results, the implications to understand the friendship of the science gifted elementary students were suggested in depth.

• Journal of The Korean Astronomical Society
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• v.52 no.6
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• pp.217-225
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• 2019

We apply a modified Convolutional Neural Network (CNN) model in conjunction with transfer learning to predict whether an active region (AR) would produce a ≥C-class or ≥M-class flare within the next 24 hours. We collect line-of-sight magnetogram samples of ARs provided by the SHARP from May 2010 to September 2018, which is a new data product from the HMI onboard the SDO. Based on these AR samples, we adopt the approach of shuffle-and-split cross-validation (CV) to build a database that includes 10 separate data sets. Each of the 10 data sets is segregated by NOAA AR number into a training and a testing data set. After training, validating, and testing our model, we compare the results with previous studies using predictive performance metrics, with a focus on the true skill statistic (TSS). The main results from this study are summarized as follows. First, to the best of our knowledge, this is the first time that the CNN model with transfer learning is used in solar physics to make binary class predictions for both ≥C-class and ≥M-class flares, without manually engineered features extracted from the observational data. Second, our model achieves relatively high scores of TSS = 0.640±0.075 and TSS = 0.526±0.052 for ≥M-class prediction and ≥C-class prediction, respectively, which is comparable to that of previous models. Third, our model also obtains quite good scores in five other metrics for both ≥C-class and ≥M-class flare prediction. Our results demonstrate that our modified CNN model with transfer learning is an effective method for flare forecasting with reasonable prediction performance.