• Title/Summary/Keyword: Variance Learning

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Improving the Performance of Machine Learning Models for Anomaly Detection based on Vibration Analog Signals (진동 아날로그 신호 기반의 이상상황 탐지를 위한 기계학습 모형의 성능지표 향상)

  • Jaehun Kim;Sangcheon Eom;Chulsoon Park
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.47 no.2
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    • pp.1-9
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    • 2024
  • New motor development requires high-speed load testing using dynamo equipment to calculate the efficiency of the motor. Abnormal noise and vibration may occur in the test equipment rotating at high speed due to misalignment of the connecting shaft or looseness of the fixation, which may lead to safety accidents. In this study, three single-axis vibration sensors for X, Y, and Z axes were attached on the surface of the test motor to measure the vibration value of vibration. Analog data collected from these sensors was used in classification models for anomaly detection. Since the classification accuracy was around only 93%, commonly used hyperparameter optimization techniques such as Grid search, Random search, and Bayesian Optimization were applied to increase accuracy. In addition, Response Surface Method based on Design of Experiment was also used for hyperparameter optimization. However, it was found that there were limits to improving accuracy with these methods. The reason is that the sampling data from an analog signal does not reflect the patterns hidden in the signal. Therefore, in order to find pattern information of the sampling data, we obtained descriptive statistics such as mean, variance, skewness, kurtosis, and percentiles of the analog data, and applied them to the classification models. Classification models using descriptive statistics showed excellent performance improvement. The developed model can be used as a monitoring system that detects abnormal conditions of the motor test.

The analysis of the in-service training program for the 1st grade English teacher in a secondary school (중등 1급 정교사(영어) 자격연수 프로그램 분석: 대전, 서울, 인천, 강원, 경기, 충남, 충북을 중심으로)

  • Kim, Yong-Oh;Kahng, Yong-Koo;Kang, Mun-Koo
    • English Language & Literature Teaching
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    • v.13 no.3
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    • pp.203-226
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    • 2007
  • This paper analyzes the in-service training program for the 1st grade English teacher in the following 7 regions: Taejeon, Seoul, Incheon, Kangwon, Kyeonggi, Chungnam and Chungbuk. It also investigates the actual conditions of the program. The analyses are performed on three categories of subjects: Teaching Profession, Refinement and English Education. The English Education category can be divided into the three aspects: language skills, communicative skills and language learning/teaching skills. Among the 7 regions, subjects under Teaching Profession, Refinement and English Education have a significant (2-3 times +/-) variance in terms of the number and credit hours of the courses. While the Refinement Program is above the standard set by Ministry of Education & Human Resources Development(MEHRD) in some regions, the Teaching Profession Program and the English Education Program is below the standard set by MEHRD in other regions. To overcome the weaknesses of the program, this paper suggests the following: 1) prescriptions for the proportion ratio of each category should be suitably modified. 2) MEHRD should observe and supervise the program of each region. 3) being organized, the program must have two parts as follows: the same mandatory subjects for all regions and optional subjects suited to each region.

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A Study on the Home Education of Family with teenagers -A Focus of Developing the Scale on the Content of Home Education- (청소년기 자녀 가족의 가정교육 연구 -가정교육 내용에 관한 척도 개발을 중심으로-)

  • Wang, Seok Sun
    • Journal of Families and Better Life
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    • v.15 no.2
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    • pp.71-71
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    • 1997
  • This study aims ai the extraction of what is universally to be taught in modern Korean Families and its scalization. That is, it attempts to provide the criterion by which we can determine what to teach adolescent in the family, not in society or school. For this purpose, this study firstly reviews the preceeding studies on the subject. As a result of the review, we postulate the hypothetical structure consisting of 11 domains. Secondary, we gather the parent's view on the topic by interviewing 496 parents with teenagers. On the basis of this study, we can construct the questionnaire(Likert scale; 5 point). After we conduct an extensive empirical research(346 parents) in order to generalize 195 items of the workedout questionnaire. We apply factor analysis(principal axis factoring, oblique (promax) rotation) in the verification of the validity. As the consequence, we select 66 items consisting, 10 factors, which explain 68% of common variance. We name the 10 educational factors extracted in the scale as follows ; The Sense of Value, Communal Society, Sex, Esteem for an ancestor & a traditional way of life, Parent-Child Relationship, the Culture life within the family, The Guide of Learning Way, Setting up the way of life, The control of one's life, Friendship. The reliability of the scale is the cronbach =0.91 which turns out to be satisfactory.

Case Study for Increasing the Learning Effect In Cyber Lecture (사이버 강좌에서 학습 효과를 높이기 위한 사례 연구)

  • Um, Jong-Seok;Cho, Sae-Hong
    • Journal of Korea Multimedia Society
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    • v.16 no.10
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    • pp.1230-1237
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    • 2013
  • Cyber lectures were expected to replace the traditional classroom lecture, yet they were criticized due to the inefficiency. With educational technology supplemented, cyber lectures have improved their efficiency through the coherence of superior planning ability and improvement in computer and network technology. This paper's purpose is to understand the factors that improve educational efficiency of cyber lectures. Cyber lecture for IT subject for software practice is created to test the educational efficiency as lecture on theories will not distinctively show the lecture efficiency. The survey was conducted to students and statistical analysis was done on collected data to analyze the factors that influence educational efficiency of created lecture.

Factors Influencing Intention to Use Smart-based Continuing Nurse Education (스마트 기술 기반 간호사 보수교육 프로그램 활용의도의 영향요인)

  • Kim, Myoung Soo;Kim, Sungmin;Jung, Hyun Kyeong;Kim, Myoung Hee
    • Journal of Korean Academy of Fundamentals of Nursing
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    • v.23 no.1
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    • pp.51-60
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    • 2016
  • Purpose: There is increasing attention to smart-learning as a new education paradigm. The purpose of this study was to identify the level of intention to use smart-based Continuing Nurse Education (CNE) and factors influencing intention to use smart-based CNE. Methods: Participants were 486 nurses from 14 organizations, including 12 hospitals, a nurses association, and an office of education. Data were collected from November 5 to 18, 2014 using self-report questionnaires. Data were analyzed using descriptive statistics, t-test, ANOVA, Pearson correlation, and stepwise multiple regression. Results: The mean score for intention to use smart-based CNE was 6.34 out of 10. The factors influencing intention to use smart-based CNE were nursing informatics competency, current unit career, and smartphone addiction. These variables explained 10% of variance in intention to use smart-based CNE. Conclusion: The findings of this study suggest that efforts to enhance the nursing informatics competency of nurses could increase usage rate of smart-based CNE. The CNE policy makers will find this study very useful and the findings of this study will help to provide insight into the best way to develop smart-based CNE.

An Ecological Study on Family Functions Perceived by Mothers with Mildly Handicapped Children (장애아 어머니가 지각하는 가족 기능성에 영향을 미치는 생태체계 변인 탐색)

  • Yoon Chong-Hee;Ha Su-Min;Kim Lee-Jin
    • Journal of Families and Better Life
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    • v.24 no.2 s.80
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    • pp.149-163
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    • 2006
  • The purposes of this study were to explore ecological variables that affect family functions and to analyze relative magnitudes of significant predictors. The study employed ecological model. Data were collected from 143 mothers of mildly handicapped children enrolled in integrated kindergartens in Seoul, Korea. The results of the study were as follows : 1. The level of family functions with mildly handicapped children were found to be moderate(M=3.21, SD=.49). 2. The hierarchical regression analysis yielded Model V as the most powerful model, explaining 79%$(Adjusted\;R^2=.787)$ of the variance. 3. The most powerful predictors throughout Model I to V were found to be maternal efficacy $({\beta}=.578,\;p<.001)$, maternal satisfaction with parent-education and counseling programs $({\beta}=.249,\;p<.001)$, husband's helps $({\beta}=.207,\;p<.01)$, and the availability of assistance other than family members $({\beta}=.232,\;p<.05)$ in the order.

Validity and Reliability of the Self-Reflection and Insight Scale for Korean Nursing Students (간호대학생의 자기-성찰 및 통찰력 측정도구 타당도 및 신뢰도 검증)

  • Song, Mi Ok;Kim, Heeyoung
    • Journal of Korean Academy of Fundamentals of Nursing
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    • v.25 no.1
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    • pp.11-21
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    • 2018
  • Purpose: The purpose of this study was to translate the Self-Reflection and Insight Scale (SRIS) into Korean and test its validity and reliability. Methods: Participants were 340 nursing students who were recruited from 5 nursing colleges in Korea. Data were collected from November 21 to December 20, 2016 and analyzed using the IBM Statistics SPSS 22.0 and AMOS 23.0 programs. Exploratory factor analysis, Confirmatory factor analysis, and concurrent validity analysis were performed. Results: For the Korean-SRIS (K-SRIS) 4 items were deleted from the original SRIS. The final scale consisted of 16 items which were sorted into- the 2 factors: self-reflection (11 items), insight (5 items). The cumulative percent of variance was 50.91%. The statistically significant correlation between K-SRIS scores and the Reflection in Learning Scale (RLS) support the concurrent validity of the K-SRIS. The reliability of the scale, Cronbach's ${\alpha}$ was .83. Conclusion: The finding indicate that the K-SRIS has validity and reliability. Therefore it can be used for measuring and developing reflection ability in nursing students.

A latent profile analysis of perceptions about Mathematics teachers in school lessons (학교수업에서 수학교사에 대한 인식의 잠재프로파일 분석)

  • Ko, Dong Hyun;Jung, Hee Sun
    • The Mathematical Education
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    • v.57 no.2
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    • pp.75-92
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    • 2018
  • Based on Perceptions about Mathematics Teachers (PMT) perceived by high school students, measured by 2189 students from Seoul Educational Longitudinal Study 2014 (SELS 2014), latent profile analysis (LPA) identified five distinct types of student groups (positive, partial positive, middle, negative, extreme negative). These student of positive, middle, and negative groups are positive, moderate and negative perceptions about math teachers. Partial positive group generally had a positive perception about mathematics teachers, extremely negative group was very negative about mathematics teachers. Both of these groups had peculiarly inconsistent trends and several anomalies. The Multinomial logistic regression analyses also indicated that individual factors (gender, major, self-concept, resilience, self-assessment, career maturity), school factors (friendship, relationship with school teachers) and parental factors (academic-relationship, emotional-relationship) were significant predictors of PMT profile groups. The Analysis of variance also indicated that mathematics class (attitude, satisfaction and atmosphere), Mathematics achievement were significant predictors of PMT profile groups. The profiling of perceptions about mathematics teachers resulted in enhanced understanding of the complex range of processes students employed. During mathematics class, implementation of smooth interactions and communications between students and teachers added in the teaching and learning of mathematics.

Effect of Kegel Exercise on Vital Capacity According to the Position: A Preliminary Study

  • Park, KangHui;Park, HanKyu
    • The Journal of Korean Physical Therapy
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    • v.32 no.4
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    • pp.217-221
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    • 2020
  • Purpose: This study examined the immediate effect of Kegel exercise on the vital capacity according to the position. Methods: Seventeen subjects participated in the study (male=7, female=10). The subjects performed Kegel exercise in two positions: sitting and hooklying. The order of exercise was conducted in a random order selected by the subjects to exclude the learning effect. The maximum voluntary ventilation (MVV) was measured using a spirometer. The vital capacity was measured according to the manual in the sitting position before the experiment. After each exercise, the vital capacity was also measured in the same way. One way repeated measures analysis of the variance (ANOVA) was used to compare the vital capacity according to the position, and a Bonferroni test was used for post hoc analysis. Results: Significant differences in vital capacity were observed after exercise than before exercise (p<0.05). Post-hoc analysis, however, revealed no difference in vital capacity according to the position (p>0.05). Conclusion: This study was a preliminary study to determine the vital capacity according to the Kegel exercise and two positions. Nevertheless, further study with several revisions of the number of subjects, duration, and time for intervention will be needed.

Analysis of the factors that influence Korean beverage consumption (전통음료 섭취에 영향을 주는 변인에 관한 분석연구)

  • 이현주;손경희;이민준
    • Korean journal of food and cookery science
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    • v.18 no.1
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    • pp.63-72
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    • 2002
  • This study was conducted to (a) investigate the frequency of Korean beverage consumption, (b) analyze the characteristics of socio-demographically classified group according to drinking frequency, (c) investigate the attitude for and awareness of Korean beverage and (d) analyze the factors which influence Korean beverage consumption. The survey was carried out by self-administered questionnaires with 2,200 subjects residing in Seoul. A total of 1,885 samples were used for analysis by using t-test, one way analysis of variance (ANOVA), Duncan's multiple comparison test, factor analysis, and analysis of covariance (ANOCOVA) with SAS computer program. Among various Korean beverage, Donggulre tea was consumed most frequently at an average of 7.4 times per month, and followed by rice beverage, Mi Su, Citron tea, Shick Hae and canned Shick Hae. Among the age groups, the group of 20s showed the lowest frequency of Korean beverage consumption exempt rice beverage. According to occupation group, middle and high school and college student groups showed a high frequency of consumption of cereal based drink such as rice beverage, Mi Su and Yulmu tea. The behavior examination aimed at learning the perceptions relevant to the choice of beverage showed that the subjects believe Korean beverage healthful and nutritious but not familiar through advertisement, not easy to buy, and not to be a habitual drink. The factors influencing the frequency of Korean beverage consumption were shown as health-related factors and habitual/practical factors.