• Journal of the Computational Structural Engineering Institute of Korea
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• v.34 no.4
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• pp.191-197
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• 2021

To calculate the induced charge of atoms in molecular dynamics, linear equations for the induced charges need to be solved. As induced charges are determined at each time step, the process involves considerable computational costs. Hence, an efficient method for calculating the induced charge distribution is required when analyzing large systems. This paper introduces the Uzawa method for solving saddle point problems, which occur in linear systems, for the solution of the Lagrange equation with constraints. We apply the accelerated Uzawa algorithm, which reduces computational costs noticeably using the Schur complement and preconditioned conjugate gradient methods, in order to overcome the drawback of the Uzawa parameter, which affects the convergence speed, and increase the efficiency of the matrix operation. Numerical models of molecular dynamics in which two gold nanoparticles are placed under external electric fields reveal that the proposed method provides improved results in terms of both convergence and efficiency. The computational cost was reduced by approximately 1/10 compared to that for the Gaussian elimination method, and fast convergence of the conjugate gradient, as compared to the basic Uzawa method, was verified.

• The Journal of the Convergence on Culture Technology
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• v.8 no.4
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• pp.91-98
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• 2022

Lifelog data continuously collected through a wearable device may contain many outliers, so in order to improve data quality, it is necessary to find and remove outliers. In general, since the number of outliers is less than the number of normal data, a class imbalance problem occurs. To solve this imbalance problem, we propose a method that applies Variational AutoEncoder to outliers. After preprocessing the outlier data with proposed method, it is verified through a number of machine learning models(classification). As a result of verification using body weight data, it was confirmed that the performance was improved in all classification models. Based on the experimental results, when analyzing lifelog body weight data, we propose to apply the LightGBM model with the best performance after preprocessing the data using the outlier processing method proposed in this study.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.29-37
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• 2020

In the past, meta-heuristic optimization algorithms were developed to solve the problems caused by complex nonlinearities occurring in natural phenomena, and various studies have been conducted to examine the applicability of the developed algorithms. The self-adaptive vision correction algorithm (SAVCA) showed excellent performance in mathematics problems, but it did not apply to complex engineering problems. Therefore, it is necessary to review the application process of the SAVCA. The SAVCA, which was recently developed and showed excellent performance, was applied to the advanced Muskingum flood routing model (ANLMM-L) to examine the application and application process. First, initial solutions were generated by the SAVCA, and the fitness was then calculated by ANLMM-L. The new value selected by a local and global search was put into the SAVCA. A new solution was generated, and ANLMM-L was applied again to calculate the fitness. The final calculation was conducted by comparing and improving the results of the new solution and existing solutions. The sum of squares (SSQ) was used to calculate the error between the observed and calculated runoff, and the applied results were compared with the current models. SAVCA, which showed excellent performance in the Muskingum flood routing model, is expected to show excellent performance in a range of engineering problems.

• Journal of the Korean Data and Information Science Society
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• v.26 no.6
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• pp.1175-1188
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• 2015

The Ministry of Education of Korea announced the university structural reform plans which reduces 160,000 of the university entrance quota during 10 years from January 2014. Because the reduction plans of entrance quota influence regional economy as well as students and universities, naive evidence of the Ministry of Education of Korea is disappointed. In this research, we forecast the total number of the university entrance exam candidate by 2032 including not only third grade high school students but also repeaters according to the 16 metropolises and provinces in Korea. We also forecast the regional university recruiting rate using the forecasts of the total number of the university entrance exam candidates. However, we can not make more realistic results because we can not apply the inter-regional movement of students to the forecast. In order to handle this limitation, we first estimated the rank of the whole 7,277 departments of all universities in Korea and assigned the quotas according to the estimated rank for each departments and then we calculated the local university recruiting rate. The estimated the university recruiting rates of 16 metropolises and provinces can provide more noticeable results of characteristics and problems than that of nationwide.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.483-496
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• 2018

NCS (National Competency Standards) has emerged as an issue of great importance amongst Korean universities and corporations. Although previously used mostly for vocational education purposes at colleges, NCS is currently receiving an increasing amount of attention from 4-year universities as well. In the ever-evolving information economy, the basic workplace skills defined by NCS, which include soft skills such as communication skills, problem-solving skills, and interpersonal skills, have now become more important than specific technical skills. This study analyzes the correlation between the basic workplace skills of NCS with participation in Formula SAE activities, a common component of Capstone design courses across North America and Europe. Data are derived from site visits to Formula SAE competitions, competition-related documents drafted by student participants, and questionnaires administered to student participants at the Formula SAE Lincoln completion and at the Korea KSAE competition. From the study findings, we claim that the basic workplace skills of NCS are closely correlated to participation in Formula SAE activities. Through a survey designed to measure the degree to which Formula SAE activities can enhance an individual's NCS Basic Workplace Skills, we find that these activities overall improved NCS basic workplace skills averaging 4.0 points above in the Likert 5-point scale. For reference the mathematical skills, communication skills, and problem-solving skills displayed statistically significantly correlation with NCS but the remaining 7 skills did not show a statistically strong correlation with NCS comparatively.

• 대한공업교육학회지
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• v.36 no.1
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• pp.1-22
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• 2011

The purpose of this study was to develop and apply activity-centered STEM education program of electricity and electronics technology are in middle schools. The program was developed on the emphasis of problem solving in real world in relation to knowledge, attitude, and skill of Science, Technology, Engineering, and Mathematics. Basically the activity-centered STEM education program was developed through three steps of preparation, development and improvement. In the preparation stage the fellowing was included: (1) need analysis of student, educator, society (2) selection of integration type (3) analyzing subject matter of electricity, electronics area (4) establishing criteria for selecting activity tasks. In the development stage the fellowing was conducted: (1) selection of activity tasks (2) setting up educational goals (3) analyzing activity and clarifing the detailed activity (4) selecting program content, (5) organization of instructional content (6) statement of instructional objectives (7) structuring STEM education program In the improvement stage the fellowing was consisted of: (1) verification of validity by experts (2) execution of pilot test and field test by students and correction of program. The results of the applied the Activity-Based STEM Education Program to 'Afterschool' activities of S middle school were as follow: First, student' satisfaction level was high. Second, student' achievement in the cognitive domain, and affective domain was positive change. Third, student' problem solving ability was positive effect.

• Archives of design research
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• v.12 no.4
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• pp.191-200
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• 1999

Improving the design ability of idea developing and creative problem solving should be started from the primary school. Design education in the primary school should be not education for design but education by design. It helps students can naturally understand the basic concept of design and experience the process of activities. Therefore primary educational circle use the term of 'Design-related activities', or 'Design-Based Education'. It can be applied to variable themes of mathematics, science, music, society as well as Art. On the Basis of these literature review, the traditional design education as a part of the art education is analyzed in two aspects of its contents and behaviors. The contents in design education involve aesthetic·symbolic, useful·functional, and scientific·technological area. And, the basic design behaviors are classified with 'know', 'perceive', 'inquire', and so on. This concept becomes the analytic frame of the present condition of design education in Korean primary school. Through the analysis, it is found that the portion of scientific·technological area in contents and 'inquire' related behaviors are relatively very low. Also, the planning and teaching methods for leading children's opportunity of creative expression are found inadequate. This study proposes the potential capability and the integrative contents of design education in primary school.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.10
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• pp.1264-1274
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• 1999

본 논문에서는 분산된 클록들을 주기적으로 동기화 시키는 분산 실시간 시스템에서 시간적 제약을 만족시키기 위한 정적/동적 시간 제약(timing constraint) 변환 기법을 제안한다. 전형적인 이산클록동기화(discrete clock synchronization) 알고리즘은 클록의 값을 순간적으로 조정하여 클록의 시간이 불연속적으로 진행한다. 이러한 시간상의 불연속성은 시간적 이벤트를 잃어버리거나 다시 발생시키는 오류를 범하게 한다.클록 시간의 불연속성을 피하기 위해 일반적으로 연속클록동기화(continuous clock synchronization) 기법이 제안되고 있지만 소프트웨어적으로 구현되면 많은 오버헤드를 유발시키는 문제점이 있다. 본 논문에서는 시간적 제약을 동적으로 변환시키는 DCT (Dynamic Constraint Transformation) 기법을 제안하였으며, 이를 통해 기존의 이산클록동기화 알고리즘을 수정하지 않고서도 클록 시간의 불연속성에 의한 문제점들을 해결할 수 있도록 하였다. 아울러 DCT에 의해 이산클록동기화 하에서 생성된 태스크 스케쥴이 연속클록동기화에 의해 생성된 스케쥴과 동일함을 증명하여 DCT의 동작이 이론적으로 정확함을 증명하였다.또한 분산 실시간 시스템에서 지역 클록(local clock)이 기준 클록과 완벽하게 일치하지 않아서 발생하는 스케쥴링상의 문제점을 다루었다. 이를 위해 먼저 두 가지의 스케쥴링 가능성, 지역적 스케쥴링 가능성(local schedulability)과 전역적 스케쥴링 가능성(global schedulability)을 정의하고, 이를 위해 시간적 제약을 정적으로 변환시키는 SCT (Static Constraint Transformation) 기법을 제안하였다. SCT를 통해 지역적으로 스케쥴링 가능한 태스크는 전역적으로 스케쥴링이 가능하므로, 단지 지역적 스케쥴링 가능성만을 검사하면 스케쥴링 문제를 해결할 수 있도록 하였고 이를 수학적으로 증명하였다.Abstract In this paper, we present static and dynamic constraint transformation techniques for ensuring timing requirements in a distributed real-time system possessing periodically synchronized distributed local clocks. Traditional discrete clock synchronization algorithms that adjust local clocks instantaneously yield time discontinuities. Such time discontinuities lead to the loss or the gain of events, thus raising serious run-time faults.While continuous clock synchronization is generally suggested to avoid the time discontinuity problem, it incurs too much run-time overhead to be implemented in software. We propose a dynamic constraint transformation (DCT) technique which can solve the problem without modifying discrete clock synchronization algorithms. We formally prove the correctness of the DCT by showing that the DCT with discrete clock synchronization generates the same task schedule as the continuous clock synchronization.We also investigate schedulability problems that arise when imperfect local clocks are used in distributed real-time systems. We first define two notions of schedulability, global schedulability and local schedulability, and then present a static constraint transformation (SCT) technique. The SCT ensures that it is sufficient to check the schedulability of a task locally in a node with a local clock, since the global schedulability of the task is derived from its local schedulability through SCT. We formally prove the correctness of SCT.

• Communications of Mathematical Education
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• v.25 no.1
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• pp.261-288
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• 2011

We examined the effects of pair assistant collaborative learning on academic achievement of the 2nd year middle school students in the three subjects such as the Probability, Properties of Figures and Similarities of Figures. In order to carry out this study, we selected 2 classes of 2nd year students in a girls middle school in the Fall semester of 2009 and set up the experiment group and comparison group by the result of academic achievement tests given in the end of the Spring semester of 2009. Pair assistant collaborative learning was adopted for students in problem solving 2 or 3 times per a week in the experiment group and each academic achievement was given at the end of each subject in both groups. Also, we had a final survey to find out students' attitude to this collaborative learning. The achievement and survey were analysed by statistical methods. We conclude that our pair assistant collaborative learning was effective in Probability and Similarities of Figures Units. According to the result of survey, this collaborative learning brought about an opportunity to promote students' community spirit through reflecting each one's role in the group.

• Journal of the Korean School Mathematics Society
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• v.16 no.1
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• pp.1-29
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• 2013

The main goal of the research is to develop instructional consulting manual to help math teachers improve classroom teaching. Improving the quality of teaching in schools is stressed as a central focus of meaningful classroom instruction and high quality education. In this research, teaching consulting was defined as an activity that covers reflection process oriented towards formative assessment and continuing professional development. Within this context, subject-specific teaching consulting and teaching professionalism with focus on PCK was reviewed. Further, the questionnaire survey was conducted to investigate the current situation of teaching consulting and teachers' needs for consulting. And also, specific examples of subject-specific consulting based on our previous consulting experiences in math classes were shown. Alternative ways to improve subject teaching were derived through the conferences where consultants and consultees analyze video-taped lessons conducted by the consultees. By those results, a manual for invigorating teaching consulting was developed. The contents of the manual consists of setting conditions of teaching consulting and its implementation in the classroom teaching. The first part of the manual contains steps to establish teaching consulting system, the qualification and role of the consultant, system evaluation, etc. The second part of the manual presents the pre-preparation, prescription and implementation and follow-up management steps. Each part of the manual provides consultants with specific guidelines for each step. Finally, recommendations for making policy related to ways to invigorate teaching consulting was suggested. It is expected that specific examples and cases of subject-specific teaching consulting presented in this research will be used to narrow the gap between theory and practice of teaching consulting, and to help math, science and English teachers develop teaching professionalism.