• Journal of applied mathematics & informatics
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• v.33 no.1_2
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• pp.203-210
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• 2015

We consider fractional Brownian motion and FARIMA process with Gaussian innovations and show that the suitably scaled distributions of the FARIMA processes converge to fractional Brownian motion in the sense of finite dimensional distributions. We figure out ACF function and estimate the self-similarity parameter H of FARIMA(0, d, 0) by using R/S method. Finally, we display power spectrum density of FARIMA process.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.3
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• pp.72-78
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• 2016

In this study, we analyzed the accidental hydrogen embrittlement affecting the track nut on a self-propelled howitzer. Tracks are key components to maintain a high degree of confidence in the operation of the self-propelled howitzer and the safety of the crew. This study analyzed the fractured surface using SEM to review accidental damage of the wedge nut. In addition, we conducted revival tests and analyzed the results to identify the cause of the wedge nut damage from hydrogen embrittlement. We should carry out factor analysis and continuous improvement of the manufacturing process to determine the accidental breakage mechanism for future enhancement of the self-propelled howitzer. This study will be the useful reference for enhancing process designs in similar products.

• Proceedings of the KWS Conference
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• 2006.10a
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• pp.178-180
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• 2006

The present article aims to develop a numerical method for numerical analysis of fusible filler behavior for self-interconnection process. The CIP(Cubic Interpolated Propagation) method is used for determination of interfaces and the CSF(Continuum Surface Force) model is adopted for evaluation of curvature. To validate these models, first, the present study performs the numerical simulation for a droplet formation and it simulates the interactions among fusible fillers inside resin under the operating condition. As a result, similar tendency is found compared to the experimental observation. This study would be a first step towards finding the optimum condition for self-interconnection process.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.505-505
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• 2000

Controlling the process by PID controller is widely used in industry by applying Ziegler-Nichols method in analyzing parameter of the controller. However, in fact. it is still necessary to tune parameter in order to obtain the best process response. This paper presents a Self-Tuning PID controller utilizes the personal computer to synthesize and analyze controller parameter as well as tune for appropriate parameter by using Dahlin method and Extrapolation. Experimental results using a Self-Tuning PID controller to control water level and temperature, it is found that the controller being developed is able to control the process very effectively and provides a good response similar to the controller used in the industry.

• Communications of Mathematical Education
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• v.28 no.2
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• pp.255-279
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• 2014

This study is to investigate the change of intelligent and affective domains through the student self-evaluation to identify causes of wrong answers. Through this evaluation, students could have opportunities to solve the given mathematical problems basically and to reflect their problem-solving process, and further to recognize which mathematical content(concepts or expressions, symbols, etc.) led them to solve the problems incorrectly or wrong. Through this process, they would correct their wrong process and answers and to reinforce the prerequisite knowledges relevant to the problems, and furthermore, to enhance problem-solving abilities. To accomplish this, this study was executed as a case study on the subject of four tenth graders. The subject consisted of two boys and two girls. In this study, three essay types of mathematical problems in tenth grade level were chosen from several domestic tests in Korea. Based on the original three essay type of problems, three types of similar problems, namely equivalent problem, similar problem, and isomorphic problems were reconstructed, respectively by the researchers. The subjects were guided to solve the original three problems, and they corrected their wrong parts of the first problem of the three problems. They solved an equivalent problem of the first problem and executed self evaluation and also corrected wrong parts. Next, they dealt with a similar problem of the first problem and executed self evaluation and also corrected wrong parts. Next, while dealing with an isomorphic problem of the first problem, the subjects did the same things. Thus, for the second and third original problems, the study was implemented in the same way. To explore their intelligent and affective domains through student self-evaluation in-depth, the subjects were interviewed formally before and after conducting the experiment and interviewed informally two times, and the recordings were audio-typed.

• KIPS Transactions on Software and Data Engineering
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• v.12 no.11
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• pp.493-504
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• 2023

The Republic of Korea is located far from the boundary of the earthquake plate, and the intra-plate earthquake occurring in these areas is generally small in size and less frequent than the interplate earthquake. Nevertheless, as a result of investigating and analyzing earthquakes that occurred on the Korean Peninsula between the past two years and 1904 and earthquakes that occurred after observing recent earthquakes on the Korean Peninsula, it was found that of a magnitude of 9. In this paper, the Korean Peninsula Historical Earthquake Record (2 years to 1904) published by the National Meteorological Research Institute is used to analyze the relationship between earthquakes on the Korean Peninsula and statistical self-similarity. In addition, the problem solved through this paper was the first to investigate the relationship between earthquake data occurring on the Korean Peninsula and statistical self-similarity. As a result of measuring the degree of self-similarity of earthquakes on the Korean Peninsula using three quantitative estimation methods, the self-similarity parameter H value (0.5 < H < 1) was found to be above 0.8 on average, indicating a high degree of self-similarity. And through graph visualization, it can be easily figured out in which region earthquakes occur most often, and it is expected that it can be used in the development of a prediction system that can predict damage in the event of an earthquake in the future and minimize damage to property and people, as well as in earthquake data analysis and modeling research. Based on the findings of this study, the self-similar process is expected to help understand the patterns and statistical characteristics of seismic activities, group and classify similar seismic events, and be used for prediction of seismic activities, seismic risk assessments, and seismic engineering.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1999.06a
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• pp.57.2-62
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• 1999

Fractal coding is image compression techniques using one of image characteristics self-transformability. In fractal image coding, the encoding process is to select the domain block similar to a range block. The reconstructed image quality of fractal image coding depends on similitude between a range block and the selected domain block. Domain block similar to a range blocks. In fact, the error of the reconstructed image adds up the generated error in encoding process and the generated error in decoding process. But current domain block estimating function considered only the encoding error. We propose a domain block estimating function to consider not only the encoding error but also the decoding error. By computer simulation, it was verified to obtain the high quality reconstructed image.

• Journal of the Korean Mathematical Society
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• v.48 no.1
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• pp.147-158
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• 2011

In this paper, we consider a multi-dimensional diffusion process in a self-similar random environment and prove a limit theorem for the shape of the full trajectory of the diffusion by using the localization phenomenon.

• Korean Journal of Mathematics
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• v.11 no.1
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• pp.35-43
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• 2003

We study the weak convergence to Fractional Brownian motion and some examples with applications to traffic modeling. Finally, we get loss probability for queue-length distribution related to self-similar process.

• The Journal of Korean Academic Society of Nursing Education
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• v.20 no.4
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• pp.482-490
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• 2014

Purpose: This research compares self-leadership, team efficacy, problem solving processes and task satisfaction in response to teaching methods applied to nursing students, and determines whether variations exist. Method: This research experiments before and after the training of a nonequivalent group. The subjects were 36 learners of action learning methods and 39 learners of nursing course methods, and the research took place from October through December 2012. Results: Prior to the training, the general features and measurable variables of the two groups of subjects were similar, and self-leadership, team efficacy, problem solving process and task satisfaction in both groups were elevated compared to pre-training. In particular, in comparison with the nursing course, there was a notable difference in scores, the action learning method receiving high scores in the problem solving process (t=2.92, p=.005) and task satisfaction (t=2.54, p=.013) Conclusion: It is recommended that educators not only conduct the practice training course for teaching methods, but also incorporate action learning.