• Title/Summary/Keyword: class-transition

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A Didactical Discussion on the Use of Mathematical Manipulatives (교구이용에 대한 교수학적 논의 -대수모델의 활용사례를 통한 교구의 효과 분석을 중심으로-)

  • 김남희
    • School Mathematics
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    • v.2 no.1
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    • pp.29-51
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    • 2000
  • In this study, we tried to suggest an example of the analysis on the use of mathematical manipulatives. Taking algebra tiles as an example of mathematical manipulatives, we analysed several effects resulted from the use of algebra tiles. The algebra tiles make it possible to do activities that are needed to introduce and explain the distributive law and factoring. The algebra tiles have a several advantages; First of all, This model is simple. Even though they cannot make algebra easy, this model can play an important role in the transition to a new algebra course. This model provides access to symbol manipulation for students who had previously been frozen out of the course because of their weak number sense. This model provides a geometric interpretation of symbol manipulation, thereby enriching students' understanding, This model supports cooperative learning, and help improve discourse in the algebra class by giving students objects to think with and talk about. On the other hand, The disadvantages of this model are as follows; the model reinforces the misconception that -x is negative, and x is positive; the area model of multiplication is not geometrically sound when minus is involved; only the simplest expressions involving minus can be represented; It is ineffective when be used the learning of already known concept. Mathematics teachers must have a correct understanding about these advantages and disadvantages of manipulatives. Therefore, they have to plan classroom work that be maximized the positive effect of manipulatives and minimized the negative effect of manipulatives.

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Research on Insulation Design of the Bushing for a 154kV Class HTS Transformer (154kV급 고온초전도 변압기용 부싱의 절연설계에 관한 연구)

  • Kwag, D.S.;Cheon, H.G.;Choi, J.H.;Kim, H.J.;Yun, M.S.;Kim, Y.S.;Kim, S.H.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.06a
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    • pp.216-217
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    • 2006
  • A common problem in many fields of cryogenic power engineering is to apply high voltage to cold parts of superconducting equipment. In many of these cases a bushing provides electrical insulation for the conductor which makes the transition from ambient temperature to the cold environment. The cryogenic high voltage bushing for the 154kV, 100MVA high temperature superconducting(HTS) transformer is described. The bushing is energized with the line-to-ground voltage between the coaxial center and outer surrounding conductors, in the axial direction there is a temperature difference from ambient to about 77 K. For the insulation design of cryogenic bushing, the arrangement of condenser cone and electrical insulation characteristics of GFRP, Air, $LN_2$ and $GN_2$ were discussed in this paper.

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Performance Analysis of Men's 110-m Hurdles using Rhythmic Units

  • Hong, Sung Hong;Ryu, Jae Kyun
    • Korean Journal of Applied Biomechanics
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    • v.28 no.2
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    • pp.79-85
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    • 2018
  • Objective: This study aimed to create a strategic training method to enhance optimal athletic ability using information from 1H to 10H rhythmic units. Method: Top three world class athletes and three national winners of 110-m hurdle finals from the 2010 Daegu International Athletics Competition and 2017 National Athletics Championship, respectively, were selected. To analyze the kinematic variables, Dartfish 9.0 was used for two-dimensional analysis. Results: Regarding the interval time from the start to the finish line, the national athletes took less time during the pure acceleration phase (start to 1H) than the foreign athletes. The horizontal velocity increase was slower after 1H; the national athletes showed a lack of ability to accelerate at the interval phases. Moreover, the hurdle clearance time between phases was longer in the national athletes than in the foreign athletes and lacked consistency. Conclusion: The national athletes lacked the ability to accelerate at the transition, maximum rhythm, rhythm maintenance, and re-acceleration phases and showed a longer hurdle clearance time. If technical improvements and strategic training methods using rhythmic units are applied for hurdling motions, the national athlete's hurdling abilities, performance, and consistency could improve.

Electron Redistribution of Clavalanate on Binding to a $\beta$-Lactamase

  • Sang-Hyun Park;Hojing Kim
    • Bulletin of the Korean Chemical Society
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    • v.14 no.4
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    • pp.491-496
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    • 1993
  • A class A ${\beta}$-lactamase from Staphylococcus aureus PC1 complexed with 3R,5R-clavulanate is studied. The starting geometry for the computation is the crystal structure of the ${\beta}$-lactamase. Docking of the clavulanate to the enzyme is done exploiting the requirements of electrostatic and shape complementarity between the enzyme and clavulanate. This structure is then hydrated by water molecules and refined by energy minimization and short molecular dynamics simulation. In the energy refined structure of this complex, the carboxyl group of the clavulanate is hydrogen bonded to Lys-234, and the the carbonyl carbon atom of the clavulanate is adjacent to the $O_{\gamma}$ of Ser-70. It is found that a crystallographic water molecule initially located at the oxyanion hole, which is formed by the two -NH group of Ser-70 and Gln-237, is replaced by the carbonyl oxygen atom of the 3R,5R-clavulanate after docking and energy reginement. The crystallographic water molecules are proved to be important in ligand binding. Glu-166 residue is found to be repulsive to the binding of clavulanate, which is in agreement with experimental observation. Arg-244 residue is found to be important to the binding of clavulanate as well as to interaction with C2 side chain of the clavulanate. The electron density redistribution of the clavulanate on binding to the ${\beta}$-lactamase in studied by an ab initio quantum-mechanical calculation. A significant redistribution of electron density of the clavulanate is induced by the enzyme, toward the enzyme, toward the transition state of the enzymatic reaction.

Evaluation of APR1400 Steam Generator Tube-to-Tubesheet Contact Area Residual Stresses

  • KIPTISIA, Wycliffe Kiprotich;NAMGUNG, Ihn
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.15 no.1
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    • pp.18-27
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    • 2019
  • The Advanced Power Reactor 1400 (APR1400) Steam Generator (SG) uses alloy 690 as a tube material and SA-508 Grade 3 Class 1 as a tubesheet material to form tube-to-tubesheet joint through hydraulic expansion process. In this paper, the residual stresses in the SG tube-to-tubesheet contact area was investigated by applying Model-Based System Engineering (MBSE) methodology and the V-model. The use of MBSE transform system description into diagrams which clearly describe the logical interaction between functions hence minimizes the risk of ambiguity. A theoretical and Finite Element Methodology (FEM) was used to assess and compare the residual stresses in the tube-to-tubesheet contact area. Additionally, the axial strength of the tube to tubesheet joint based on the pull-out force against the contact joint force was evaluated and recommended optimum autofrettage pressure to minimize residual stresses in the transition zone given. A single U-tube hole and tubesheet with ligament thickness was taken as a single cylinder and plane strain condition was assumed. An iterative method was used in FEM simulation to find the limit autofrettage pressure at which pull-out force and contact force are of the same magnitude. The joint contact force was estimated to be 20 times more than the pull-out force and the limit autofrettage pressure was estimated to be 141.85MPa.

A study on the Change of University Education Based on Fliped Learning Using AI (AI 쳇봇을 활용한 플립러닝 기반의 대학교육의 변화)

  • Kim, Ock-boon;Cho, Young-bok
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.22 no.12
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    • pp.1618-1624
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    • 2018
  • The undergraduate structure based on flipped learning should be a necessary course to cultivate value creation capability based on students' problem solving capability through the change of university education in the fourth industrial revolution era. Flipped learning stimulated the learner's high order thinking and activates communication between the faculty-student and the students through the use of activity oriented teaching strategy. Introduction and spread of Flipping Learning combining project-based learning with MOOC is required. The professor should be able to apply net teaching and learning methods using flipping learning and active learning, and develop class contents reflecting new knowledge, information and technology. As the introduction and spread of AI-based(E-Advisor, chat bot et al) learning consulting, Which is becoming increasingly advanced, the transition to "personalized education" that meets the 4th Industrial Revolution should be made.

Condition assessment of stay cables through enhanced time series classification using a deep learning approach

  • Zhang, Zhiming;Yan, Jin;Li, Liangding;Pan, Hong;Dong, Chuanzhi
    • Smart Structures and Systems
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    • v.29 no.1
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    • pp.105-116
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    • 2022
  • Stay cables play an essential role in cable-stayed bridges. Severe vibrations and/or harsh environment may result in cable failures. Therefore, an efficient structural health monitoring (SHM) solution for cable damage detection is necessary. This study proposes a data-driven method for immediately detecting cable damage from measured cable forces by recognizing pattern transition from the intact condition when damage occurs. In the proposed method, pattern recognition for cable damage detection is realized by time series classification (TSC) using a deep learning (DL) model, namely, the long short term memory fully convolutional network (LSTM-FCN). First, a TSC classifier is trained and validated using the cable forces (or cable force ratios) collected from intact stay cables, setting the segmented data series as input and the cable (or cable pair) ID as class labels. Subsequently, the classifier is tested using the data collected under possible damaged conditions. Finally, the cable or cable pair corresponding to the least classification accuracy is recommended as the most probable damaged cable or cable pair. A case study using measured cable forces from an in-service cable-stayed bridge shows that the cable with damage can be correctly identified using the proposed DL-TSC method. Compared with existing cable damage detection methods in the literature, the DL-TSC method requires minor data preprocessing and feature engineering and thus enables fast and convenient early detection in real applications.

A Study on the Health Changes of Students in Long-Term Online Classes due to COVID-19

  • Seon Ahr Cho;Hong Chul Chae;Jun Sik Min;Seong Jae Lee
    • International Journal of Advanced Culture Technology
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    • v.11 no.3
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    • pp.18-25
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    • 2023
  • The COVID-19 pandemic has had a significant impact on the educational landscape for students across the globe, leading to a shift towards long-term online learning. This study aims to examine the changes in the health status of college and university students before and after the transition to online classes. We conducted a survey questionnaire among 200 students enrolled at K University in Gangwon-do, including participants from both the Department of Visual Optics and the Department of Physical Therapy. The survey employed a 5-point Likert scale to evaluate a range of health-related factors, including physical and mental well-being, alterations in lifestyle, and academic performance. Both male and female students experienced a decline in physical strength and exercise during the online class period, while mental health and overall happiness showed improvement, particularly among female students. Notable shifts in lifestyle emerged, including an increased usage of electronic devices and enhanced familial connections. The study also shed light on intriguing trends related to academic accomplishments and adherence to official quarantine guidelines. In sum, the findings of this study offer valuable foundational information for the maintenance of students' well-being during online learning, as well as the development of effective strategies for online education in future academic settings.

A Study on the Changes in Student's Perceptions of the Value of ICT Use in the Post-Corona Era (포스트 코로나 시대에 따른 학생들의 ICT 활용 가치 인식 변화에 따른 연구)

  • Kim, Ah-ra;Kim, Eui-Jeong;Kim, Chang-Suk;Chung, Jong-In;Kang, Shin-Cheon
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2021.10a
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    • pp.478-481
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    • 2021
  • With the transition to non-face-to-face classes due to the outbreak of COVID-19, education at school sites is moving in a different direction from traditional lecture-style classes. Accordingly, several online platforms have emerged, and our education is in a transitional period of class change. As a result, after a survey of the currently used online platform, where various contrasts clearly exist, compared with the report before the outbreak of COVID-19, students' perception of ICT usage ability in terms of affective, psychic, and value perception changes want to check

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How Chinese Online Media Users Respond to Carbon Neutrality: A Quantitative Textual Analysis of Comments on Bilibili, a Chinese Video Sharing Platform

  • Zha Yiru
    • Asian Journal for Public Opinion Research
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    • v.11 no.2
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    • pp.145-162
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    • 2023
  • This research investigates how users of Bilibili, a video sharing website based in China have responded to carbon neutrality. By conducting quantitative textual analyses on 3,311 comments on Bilibili using LDA topic extraction and content statistics, this research discovers that: (1) Bilibili users have assigned more weight to geopolitical topics (56.3%) than energy (22.0%) and environmental topics (21.7%). (2) When assessing carbon neutrality, Bilibili users considered geopolitical (53.8%) and energy factors (15.8%) more heavily than factors related to the class (9.2%), economy (8.9%), environment (8.7%), and definition (3.6%). (3) More Bilibili users had negative (64.6%) attitudes towards carbon neutrality, with only a small portion of them expressing positive (26.8%) and neutral (8.6%) attitudes. (4) Negative attitudes towards carbon neutrality were mainly driven by geopolitical concerns about the West's approach to China, other countries' free-riding on China's efforts and the West's manipulation of rules, doubts about the feasibility of energy transition and suspicion of capitalists exploiting consumers through this concept. This research highlights the geopolitical concerns behind the environmental attitudes of Chinese people, deepening our understanding to psychological constructs and crisis sensitivity of Chinese people towards environmental issues.