• The Korean Journal of Applied Statistics
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• v.32 no.3
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• pp.349-374
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• 2019

A class imbalance problem arises when one class outnumbers the other class by a large proportion in binary data. Studies such as transforming the learning data have been conducted to solve this imbalance problem. In this study, we compared resampling methods among methods to deal with an imbalance in the classification problem. We sought to find a way to more effectively detect the minority class in the data. Through simulation, a total of 20 methods of over-sampling, under-sampling, and combined method of over- and under-sampling were compared. The logistic regression, support vector machine, and random forest models, which are commonly used in classification problems, were used as classifiers. The simulation results showed that the random under sampling (RUS) method had the highest sensitivity with an accuracy over 0.5. The next most sensitive method was an over-sampling adaptive synthetic sampling approach. This revealed that the RUS method was suitable for finding minority class values. The results of applying to some real data sets were similar to those of the simulation.

• The Journal of Korean Philosophical History
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• no.42
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• pp.39-70
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• 2014

Neo-Confucianism of Myungjae Yoon Jeung either accepted Yulgok Neo-Confucianism as it was or modified it. In this study, his Neo-Confucianism was divided into acceptance and modification in Yulgok Neo-Confucianism and examined. In the acceptance of Yulgok Neo-Confucianism, it was clarified that Neo-Confucianism of Myungjae Yoon Jeung thoroughly inherited characteristics of Yulgok Neo-Confucianism, including 'Yiguijimyo', 'Yitongguiguk' and 'Guibalyiseungildo'. However, Myungjae was not just satisfied with inheriting Yulgok Neo-Confucianism as it was, but modified and inherited the theory of Yulgok by suggesting his own original preaching. There were three original preaching of his in overall; 'emphasis on the control of Li', 'argument method on a theory of gaining knowledge by the study of things', and 'perception on moral mind, human mind and human desire'. Ultimately, it is concluded that Myungjae modified, inherited and developed Yulgok Neo-Confucianism to adjust a theory of Neo-Confucianism in a position of 'Yiguijimyo', based on 'a theory of Guibalyiseungildo' of Yulgok as a Confucian scholar of Giho school. It is consistent with his life philosophy that he avoided speculative arguments on Neo-Confucianism and pursued solid study(實工) with solid mind(實心). It is also consistent with his view of learning that he believed that theories of ancient sages were already rich that we should read them and practice their true knowledge(眞知), and making an effort on writing regardless of them was not a study of Mushil(務實). However, due to his younger students, he was classified as a scholar who emphasized the control of 'Li' the most in Yulgok school, and a new academic tie of Giho Soron was created. It is the most important significance that Neo-Confucianism of Myungjae has in that of Giho.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.6
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• pp.561-568
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• 2020

Wave measurements using X-band radar have many advantages compared to other wave gauges including wave-rider buoy, P-u-v gauge and Acoustic Doppler Current Profiler (ADCP), etc.. For example, radar system has no risk of loss/damage in bad weather conditions, low maintenance cost, and provides spatial distribution of waves from deep to shallow water. This paper presents new methods for estimating significant wave heights of X-band marine radar images using Artificial Neural Network (ANN). We compared the time series of estimated significant wave heights (Hs) using various estimation methods, such as signal-to-noise ratio (${\sqrt{SNR}}$), both and ${\sqrt{SNR}}$ the peak period (TP), and ANN with 3 parameters (${\sqrt{SNR}}$, TP, and Rval > k). The estimated significant wave heights of the X-band images were compared with wave measurement using ADCP(AWC: Acoustic Wave and Current Profiler) at Hujeong Beach, Uljin, Korea. Estimation of Hs using ANN with 3 parameters (${\sqrt{SNR}}$, TP, and Rval > k) yields best result.

• The Journal of Korean Society for School & Community Health Education
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• v.22 no.4
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• pp.49-60
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• 2021

Objectives: Laboratories have various latent physical, chemical, biological, and ergonomical factors according to the diversification and fusion of research and development activities. This study aims to investigate the chemical exposure concentrations of college laboratories and evaluate their health risks, and use them as basic data to promote the health of college students. Methods: The sampling and analysis of harmful chemicals in the air in laboratories were performed using Method 1500 of the U.S. National Institute for Occupational Safety and Health (NIOSH)의 Method 1500. The harmful chemicals in the laboratories were divided into carcinogenic and non-carcinogenic chemicals. Risk assessment was performed using the cancer risk (CR) for carcinogenic chemicals and using the hazard index (HI) for non-carcinogenic chemicals. Results: The harmful chemicals in college laboratories consisted of acetone, diethyl ether, methylene chloride, n-hexane, ethyl acetate, chloroform, tetrahydrofuran, toluene, and xylenes. They showed the highest concentrations in laboratories A (acetone 0.001~2.34ppm), B (chloroform 0.95~6.35ppm), C (diethyl ether 0.08~8.68ppm), and D (acetone 0.07~14.96ppm). The risk assessment result for non-carcinogenic chemicals showed that the HI of methylene chloride was 2.052 for men and 2.333 for women, the HI of N-hexane was 4.442 for men and 5.05 for women. Thus, the HI values were higher than 1. The risk of carcinogenic chemicals is determined by an excess cancer risk (ECR) value of 1.0×10^-5, which means that one in 100,000 people has a cancer risk. The ECRs of chloroform exceeded 1.0×10^-5 for both men and women, indicating the possibility of cancer risk. Conclusion: College laboratories showed the possibility of non-carcinogenic health risks for methylene chloride, n-hexane, tetrahydrofuran (THF), toluene, and xylenes, and carcinogenic health risks for chloroform, methylene chloride. However, this study used the maximum values of measurements to determine the worst case, and assumed that the subjects were exposed to the corresponding concentrations continuously for 8 hours per day for 300 days per year. In consideration of the nature of laboratory environment in which people are intermittently exposed, rather than continuously, to the chemicals, the results of this study has an element of overestimation.

• Journal of the Korean Society of Radiology
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• v.16 no.1
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• pp.25-34
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• 2022

Brain computed tomography (CT) is useful for brain lesion diagnosis, such as brain hemorrhage, due to non-invasive methodology, 3-dimensional image provision, low radiation dose. However, there has been numerous misdiagnosis owing to a lack of radiologist and heavy workload. Recently, object detection technologies based on artificial intelligence have been developed in order to overcome the limitations of traditional diagnosis. In this study, the applicability of a deep learning-based YOLOv5s model was evaluated for brain hemorrhage detection using brain CT images. Also, the effect of hyperparameters in the trained YOLOv5s model was analyzed. The YOLOv5s model consisted of backbone, neck and output modules. The trained model was able to detect a region of brain hemorrhage and provide the information of the region. The YOLOv5s model was trained with various activation functions, optimizer functions, loss functions and epochs, and the performance of the trained model was evaluated in terms of brain hemorrhage detection accuracy and training time. The results showed that the trained YOLOv5s model is able to provide a bounding box for a region of brain hemorrhage and the accuracy of the corresponding box. The performance of the YOLOv5s model was improved by using the mish activation function, the stochastic gradient descent (SGD) optimizer function and the completed intersection over union (CIoU) loss function. Also, the accuracy and training time of the YOLOv5s model increased with the number of epochs. Therefore, the YOLOv5s model is suitable for brain hemorrhage detection using brain CT images, and the performance of the model can be maximized by using appropriate hyperparameters.

• Journal of Internet of Things and Convergence
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• v.9 no.6
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• pp.57-62
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• 2023

This research is a comparative analysis of the U.S. S&P 500 index using the volatility breakout strategy against the Buy and Hold approach. The volatility breakout strategy is a trading method that exploits price movements after periods of relative market stability or concentration. Specifically, it is observed that large price movements tend to occur more frequently after periods of low volatility. When a stock moves within a narrow price range for a while and then suddenly rises or falls, it is expected to continue moving in that direction. To capitalize on these movements, traders adopt the volatility breakout strategy. The 'k' value is used as a multiplier applied to a measure of recent market volatility. One method of measuring volatility is the Average True Range (ATR), which represents the difference between the highest and lowest prices of recent trading days. The 'k' value plays a crucial role for traders in setting their trade threshold. This study calculated the 'k' value at a general level and compared its returns with the Buy and Hold strategy, finding that algorithmic trading using the volatility breakout strategy achieved slightly higher returns. In the future, we plan to present simulation results for maximizing returns by determining the optimal 'k' value for automated trading of the S&P 500 index using artificial intelligence deep learning techniques.

• The Journal of the Convergence on Culture Technology
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• v.10 no.1
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• pp.71-79
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• 2024

ChatGPT, an interactive artificial intelligence (AI) chatbot developed by Open AI in the U.S., gaining popularity with great repercussions around the world. Some academia are concerned that ChatGPT can be used by students for plagiarism, but ChatGPT is also widely used in a positive direction, such as being used to write marketing phrases or website phrases. There is also an opinion that ChatGPT could be a new future for "search," and some analysts say that the focus should be on fostering rather than excessive regulation. This study analyzed consciousness about ChatGPT for college students through a survey of their perception of ChatGPT. And, plagiarism inspection systems were prepared to establish an education support model using ChatGPT and ChatGPT. Based on this, a university education support model using ChatGPT was constructed. The education model using ChatGPT established an education model based on text, digital, and art, and then composed of detailed strategies necessary for the era of the 4th industrial revolution below it. In addition, it was configured to guide students to use ChatGPT within the permitted range by using the ChatGPT detection function provided by the plagiarism inspection system, after the instructor of the class determined the allowable range of content generated by ChatGPT according to the learning goal. By linking and utilizing ChatGPT and the plagiarism inspection system in this way, it is expected to prevent situations in which ChatGPT's excellent ability is abused in education.

• Archives of design research
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• v.17 no.3
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• pp.221-230
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• 2004

Design textbooks for general education bring our attention to the education of design as a part of whole education. In this vein, this thesis tried to analyze and discuss on the current status of design education contents included in the 7th educational curriculum of the Art & Life. This study had a historical review of the contents of arts education as well as a review of theoretical contents in art education. Also this thesis analyzed five types of Art & Life text books currently used at high schools with weight given to the design and to the status of pictorial coverage in the text books. Finally, the thesis presented problems of design education through a comparative analysis of high school arts education and design education. Through the analysis, inequality of design contents in education was reported. It was clearly attributable to the backgrounds of text book writers. For example, authors with graphic design backgrounds tended to lack product and environment design concepts, while hand craft section of text books all showed a biased contents towards traditional Korean arts. In the analysis of pictorial coverage, similar to the composition of academic contents, coverage was concentrated in the graphic design areas; inequality in quantity of pictures found with a ratio of 1 to 4. In terms of areas of arts, design contents in text books were concentrated only in arts creation chapters among the 3 major areas of arts appreciation, understanding, and creation. Design education is attained in an atmosphere of creativity and the provision of ample teaching material. It is because diverse contents will generate the development of arts. When compared to design education curriculum of U.S. and Japan, these creativity put their focus of design education in the understanding and emotional contacts, so that every application is easily attained. In terms of expression learning, creativity and diversity of material are emphasized. From Kindergarten to middle, and high school periods, apparently the care contents of deign is emphasized. A textbook in the 7th education curriculum is one of the sources for education. In designing text books, learning process should be emphasized following subjects and natures of arts so that creativity can be achieved. Therefore, a systematic approach for design research and educational development for material would be needed in textbook design.

• The Journal of Korean Philosophical History
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• no.23
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• pp.155-180
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• 2008

Suam(遂庵) Kwon Sang-Ha(權尙夏) was a very important character in the late Chosoen Dynasty. He was a representative of the academic circles(school of Uam) and political circles(Nolon; 老論) after Uam(尤庵) Song Si-Yeol(宋時烈, 1607-1689). He represented learning and thought and undertaking of his academic circles and political circles, and handed down to his pupils. He thought his mission was "lighting the laws of heaven and aligning the human mind," "stopping the heretical study and repulsing uncivilization", to reform good virtues of humanity and justice. Kwon Sang-Ha was a successor of Song Si-Yeol, He succeeded learning and thought of his teacher and practiced "Upright"(直) and the Thought of ChunChu(春秋). He emphasized "Upright" as a fundamental principle, like his teacher. He thought ChuHsi(朱熹, 1130-1200) was the master who had inherited the spirit of Confucianism and Chosoen was the only country to successfully inherit this spirit of Confucianism. He declared any study counter to the study of ChuHsi as a rebellious pursuit. Therefore he rejected all other studies. He tried to "stop the heretical 'ism' and repulse uncivilization" and present this ideology as 'the Right way of Human Society(世道)'. He made efforts to reorganize books of ChuHsi to make perfect Book of righteousness with Song Si-Yeol. And he established Hwayang shrine, MandongMyo(萬東廟), Deabodan(大報壇) etc, in memory of fidelity and large rightness. Kwon Sang-Ha did these undertaking to establish 'Public morals and the Right way of Human Society(世道)' with self-confidence. In Dispute on the nature of man and animal(人物性同異論), he gives his approval to Han Won-Jin's opinion. Han Won-Jin's opinion was "the nature of man and animal is Different"(人物性異論). Whenever serious political accidents occurred, he took the lead to protect his teacher, Song Si-Yeol. The reason he did this was not because of his personal feelings for his teacher, but because of promoting 'Public morals(世道)' and 'Confucianism.' Kwon Sang-Ha regarded Mind control Law of "Upright" and the thought of ChunChu as his moralities, and was concerned about real politics and opposed social irregularities. Kwon Sang-Ha succeeded Song Si-Yeol's thought of "Upright" and volition of making an inroad on the Chung(淸), and gave to his political circles(Nolon; 老論) as a law of mind and mission.

• Korean Journal of Remote Sensing
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• v.39 no.5_1
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• pp.481-493
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• 2023

In high-density urban areas, the urban heat island effect increases urban temperatures, leading to negative impacts such as worsened air pollution, increased cooling energy consumption, and increased greenhouse gas emissions. In urban environments where it is difficult to secure additional green spaces, rooftop greening is an efficient greenhouse gas reduction strategy. In this study, we not only analyzed the current status of the urban heat island effect but also utilized high-resolution satellite data and spatial information to estimate the available rooftop greening area within the study area. We evaluated the mitigation effect of the urban heat island phenomenon and carbon sequestration capacity through temperature predictions resulting from rooftop greening. To achieve this, we utilized WorldView-2 satellite data to classify land cover in the urban heat island areas of Busan city. We developed a prediction model for temperature changes before and after rooftop greening using machine learning techniques. To assess the degree of urban heat island mitigation due to changes in rooftop greening areas, we constructed a temperature change prediction model with temperature as the dependent variable using the random forest technique. In this process, we built a multiple regression model to derive high-resolution land surface temperatures for training data using Google Earth Engine, combining Landsat-8 and Sentinel-2 satellite data. Additionally, we evaluated carbon sequestration based on rooftop greening areas using a carbon absorption capacity per plant. The results of this study suggest that the developed satellite-based urban heat island assessment and temperature change prediction technology using Random Forest models can be applied to urban heat island-vulnerable areas with potential for expansion.