• Title/Summary/Keyword: student-t

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Forecasting Modeling of Heavy Tail Typed Demand using Student's t-Copula Fitting in Supply Chain Management (Student's t-Copula 적합을 통한 Heavy Tail형 SCM 수요 데이터의 모델링 및 분석)

  • Kim, Taesung;Lee, Hyunsoo
    • Journal of Digital Convergence
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    • v.11 no.9
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    • pp.103-111
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    • 2013
  • As the demand-oriented management has been getting important in Supply Chain Management (SCM), various forecasting methods have been suggested including regression analyses. However, dependency structures among variables have been captured by a correlation coefficient, only. It results in inaccurate demand predictions. This paper suggests a new and effective forecasting modeling framework using student's t-copula function. In order to show overall modeling procedures framework, heavy tail typed numerical data and its copula estimations are provided. The suggested methodology can contribute to decrease the bullwhip effect and to stabilize volatile environment in a supply chain network.

The Effects of PBL-based Data Science Education classes using App Inventor on elementary student Computational Thinking and Creativity improvement (앱인벤터를 활용한 PBL 기반 데이터 사이언스 교육 수업이 초등학생의 컴퓨팅 사고력과 창의성 향상에 미치는 효과)

  • Kim, Yongmin
    • Journal of The Korean Association of Information Education
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    • v.24 no.6
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    • pp.551-562
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    • 2020
  • The purpose of this study is to investigate the effects of Data Science Education classes using PBL-based App Inventor on elementary student Computational Thinking and Creativity. Based on the results of the pre-requisite analysis by Rossett's demand analysis model, PBL-based Data Science Education class was designed according to the procedure of ADDIE model which is 42 hours of classroom instruction for elementary student. As a result of the Paired t-test, it was proved that the Computational Thinking was statistically significantly improved in the post-test. In addition, as a result of the Paired t-test and Wilcoxon's signed rank test, it was found that the sub-factors of Creativity were 'Originality', 'Fluency', 'Closure', 'Average', and 'Index'. Therefore, it was confirmed that the PBL-based Data Science Education class using App Inventor is effective in improving Computational Thinking and Creativity of elementary student.

A Study on Middle School Student's Application of Clothing & Textiles Section in Technology-Home Economics (「기술·가정」교과 중 의생활 영역에 대한 중학생의 학습활용도에 관한 연구)

  • Kim, Kyung-Sook
    • Journal of the Korea Fashion and Costume Design Association
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    • v.12 no.4
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    • pp.159-171
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    • 2010
  • The purposes of this study is to find middle school student's application of Clothing & Textiles Section in Technology-Home Economics. The samples are 298 middles school students in Kangneung. For the statistics analysis of this study, frequency, mean, Cronbach's ${\alpha}$ coefficient, one way ANOVA, t-test were calculated. The results of this study are summarized follows; 1) Middle school student's application of Clothing & Textiles Section is relatively low. Middle school student's need of Clothing & Textiles Section and recognition of Technology-Home Economic are relatively high. But Middle school student's preference of Technology-Home Economic is relatively low. 2) Variables that affect middle school student's recognition of Technology-Home Economic are number of sibling and sibling ranking. 3) Variables that affect middle school student's need of Clothing & Textiles Section are recognition and preference of Technology-Home Economic. 4) Variables that affect middle school student's application of Clothing & Textiles Section are recognition and preference of Technology-Home Economic and need of Clothing & Textiles Section.

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The Roles of Online Instructional Facilitators and Student Performance of Online Class Activity

  • LEE, Jung Wan
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.8
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    • pp.723-733
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    • 2020
  • The study investigates the effects of online instructional facilitator's qualities on student performance of online class activities. The study explores the roles of instructional facilitators who may influence student performance of online class activities and their academic achievement. The study employs a set of aggregated data from 1,362 subjects and 10 facilitators who participated in multiple online classes. The results of independent samples t-test reveal that the student performance in online classes has no association with facilitators' educational background or academic degree, as well as demographic characteristics, student evaluation records and instructional achievement. The results of multiple regression analysis show that the facilitator engagement has a positive relation to the enhancement of student interaction, reading discussion messages, and the quality of discussion messages in online discussions. The results of correlation analysis show that the facilitator engagement has a positive impact on both increasing the number of reading discussion messages and enhancing the quality of discussion messages. The facilitator engagement increases the quantity of reading discussion postings and enhances the quality of discussion messages, which would be a substantial contribution to student performance by facilitators. The findings suggest that student performance and academic achievement in online classes are not independent of facilitator engagement.

Comparison of Perceptions about Teaching Practices by Student Teachers Before and After Practice Teaching (예비교사의 교육실습 전후 인식비교)

  • Choi, Jin Sook
    • Korean Journal of Child Studies
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    • v.26 no.4
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    • pp.113-123
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    • 2005
  • This study compared student teachers' perceptions about teaching practices and the current state of practice teaching before and after practice teaching. Subjects were 96 students at three-year colleges in Suncheon, Jollanam-do. The survey used a questionnaire, 'kindergarten teachers' recognition of practice teaching and the current state of practice teaching,'(Woo and Choi 2004), revised for this research. Differences were observed in mean scores between before and after practice teaching(t=4.30, p<.001). In sub-areas, significant differences were observed in the role of student teachers, the contents of teaching, support system, evaluation and preliminary guidance(p<.001), but not in the evaluation of practice teaching and student teachers' attitudes(p>.05). This information should be beneficial for teachers' colleges in preparation of practice teaching programs.

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A Study on the Relationship between Personality Type, GPA of Student Majoring in Flight Operation (항공운항전공학생의 성격유형과 학업성취도의 관계에 대한 연구)

  • Han, K.K.
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.13 no.3
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    • pp.1-8
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    • 2005
  • The purpose of this study was to identify the relationship between personality type and GPA scores of the student majoring flight operation. The data were collected from 96 "H' University student. MBTI Test was selected and used to analyze student's personality type. The results from MBTI Test and GPA scores were analyze by SPSS 10.0 package. I found that E, S, T, J Type, SJ, ST Type, ESTJ, ISTJ Type student are dominated. There were no significant relationship between personality type and GPA scores. The effective teaching strategies have to be considered for each personality type for better education.

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The Relationship between Stress and Leisure Satisfaction of College Student Athletes (대학 운동부 학생들의 스트레스와 여가만족과의 관계)

  • Chon, Tae-Jun
    • Journal of Wellness
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    • v.6 no.2
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    • pp.139-147
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    • 2011
  • The purpose of this study was to examine the relationship between stress and leisure satisfaction of college student athletes. The participants comprised 140 of the college student athletes. The measures were composed of stress inventory and leisure satisfaction scale. The data were analyzed by SPSS 17.0 Version frequency analysis, reliability analysis, confirmatory factor analysis, independent sample t-test, one-way ANOVA, and multiple regression analysis were performed. The level of significance was set up .05. The results were as follows: First, according to college, there was significant difference in economic burden, environmental condition, and course factor. Second, in regard with multiple regression analysis on relationships between the stress and leisure satisfaction of the college student athletes, discriminative evaluation, environmental condition, and course factor had positive effect on leisure satisfaction.

Influential Factors on Teaching Evaluation Scores in Engineering Subjects: Participating in CTL Program and Making of CQI (공학 교과목의 강의평점에 영향을 미치는 요인: CTL 프로그램 참여와 CQI 작성을 중심으로)

  • Kim, Youngki;Hur, Youngju
    • Journal of Engineering Education Research
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    • v.22 no.3
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    • pp.59-67
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    • 2019
  • The purpose of this study is to analyze that hours for participating in CTL program and whether or not make of CQI have a effect on the student evaluation about teaching of engineering professor. This inquiry have done a multiple regression analysis that student evaluation grade of teaching on 2018-1st semester of 240 engineering subjects of N University in Chungcheongnam-do as dependent variable, and background factors and work factors as independent variable. Research results is follows. First, employment type haven't a effect on teaching evaluation scores. And subject type, student' concentration of class, teaching evaluation pre-scores have a positive effect on teaching evaluation rating, but student number have a negative effect. Second, hours for participating in CTL program haven't a effect on teaching evaluation scores, but to make of CQI report have a positive effect on teaching evaluation scores. And I suggested to make CQI for improve teaching evaluation scores and manage the quality of education.

CONFLICT AMONG THE SHRINKAGE ESTIMATORS INDUCED BY W, LR AND LM TESTS UNDER A STUDENT'S t REGRESSION MODEL

  • Kibria, B.M.-Golam
    • Journal of the Korean Statistical Society
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    • v.33 no.4
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    • pp.411-433
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    • 2004
  • The shrinkage preliminary test ridge regression estimators (SPTRRE) based on Wald (W), Likelihood Ratio (LR) and Lagrangian Multiplier (LM) tests for estimating the regression parameters of the multiple linear regression model with multivariate Student's t error distribution are considered in this paper. The quadratic biases and risks of the proposed estimators are compared under both null and alternative hypotheses. It is observed that there is conflict among the three estimators with respect to their risks because of certain inequalities that exist among the test statistics. In the neighborhood of the restriction, the SPTRRE based on LM test has the smallest risk followed by the estimators based on LR and W tests. However, the SPTRRE based on W test performs the best followed by the LR and LM based estimators when the parameters move away from the subspace of the restrictions. Some tables for the maximum and minimum guaranteed efficiency of the proposed estimators have been given, which allow us to determine the optimum level of significance corresponding to the optimum estimator among proposed estimators. It is evident that in the choice of the smallest significance level to yield the best estimator the SPTRRE based on Wald test dominates the other two estimators.

Coronary Artery Stenosis Quantification for Computed Tomography Angiography Based on Modified Student's t-Mixture Model

  • Sun, Qiaoyu;Yang, Guanyu;Shu, Huazhong;Shi, Daming
    • ETRI Journal
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    • v.39 no.5
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    • pp.662-671
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    • 2017
  • Coronary artery disease (CAD) is a major cause of death in the world. As a non-invasive imaging modality, computed tomography angiography (CTA) is now usually used in clinical practice for CAD diagnosis. Precise quantification of coronary stenosis is of great interest for diagnosis and treatment planning. In this paper, a novel cluster method based on a Modified Student's t-Mixture Model is applied to separate the region of vessel lumen from other tissues. Then, the area of the vessel lumen in each slice is computed and the estimated value of it is fitted with a curve. Finally, the location and the level of the most stenoses are captured by comparing the calculated and fitted areas of the vessel. The proposed method has been applied to 17 clinical CTA datasets and the results have been compared with reference standard degrees of stenosis defined by an expert. The results of the experiment indicate that the proposed method can accurately quantify the stenosis of the coronary artery in CTA.