• Geomechanics and Engineering
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• v.33 no.2
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• pp.175-182
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• 2023

In general, the design of structures and its construction processes are fundamentally dependent on their foundation and supporting ground. Thus, it is imperative to understand the behavior of the soil under certain stress and drainage conditions. As it is well known that certain characteristics and behaviors of soils with fines are highly dependent on water content, it is critical to accurately measure and identify the status of the soils in terms of water contents. Liquid limit is one of the important soil index properties to define such characteristics. However, liquid limit measurement can be affected by the proficiency of the operator. On the other hand, dynamic properties of soils are also necessary in many different applications and current testing methods often require special equipment in the laboratory, which is often expensive and sensitive to test conditions. In order to address these concerns and advance the state of the art, this study explores a novel method to determine the liquid limit of cohesive soil by employing video-based vibration analysis. In this research, the modal characteristics of cohesive soil columns are extracted from videos by utilizing phase-based motion estimation. By utilizing the proposed method that analyzes the optical flow in every pixel of the series of frames that effectively represents the motion of corresponding points of the soil specimen, the vibration characteristics of the entire soil specimen could be assessed in a non-contact and non-destructive manner. The experimental investigation results compared with the liquid limit determined by the standard method verify that the proposed method reliably and straightforwardly identifies the liquid limit of clay. It is envisioned that the proposed approach could be applied to measuring liquid limit of soil in practical field, entertaining its simple implementation that only requires a digital camera or even a smartphone without the need for special equipment that may be subject to the proficiency of the operator.

• Journal of Convergence for Information Technology
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• v.12 no.3
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• pp.252-258
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• 2022

In this study, we propose a method for analyzing students' understanding of probability and statistics in small lectures at universities. A computer-based test for probability and statistics was performed on 95 science and engineering college students. After dividing the students' responses into 7 clusters using the Robust PCA and the Gaussian mixture model, the achievement of each subject was analyzed for each cluster. High-ranking clusters generally showed high achievement on most topics except for statistical estimation, and low-achieving clusters showed strengths and weaknesses on different topics. Compared to the widely used PCA-based dimension reduction followed by clustering analysis, the proposed method showed each group's characteristics more clearly. The characteristics of each cluster can be used to develop an individualized learning strategy.

• Korea Trade Review
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• v.41 no.5
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• pp.163-185
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• 2016

The impact of global trade on developing countries is a critical subject. Especially in this country, under difficult conditions like political issues with North Korea, achieved a trade surplus of 90.2 billion dollars last year. While the service trade recorded a deficit of 15.7 billion dollars in the same period. According to WTO, services are either the result of a production activity that changes the conditions of the consuming units (transformation services), or facilitates the exchange of products or financial assets (margin services). To unify and compare with the trade and service statistics of countries, they assorted 12 classifications of services like Manufacturing service on physical inputs owned by others, Maintenance and repair service n.i.e., Transport, Travel, Construction, Insurance and pension service, Financial service, Charges for the use of intellectual property n.i.e., Telecommunications, Computer and information services, Other business services, Personal, cultural and recreational services, and Government goods and services n.i.e. Thus, this study is to estimate the international competitiveness of service trade between 2006 and 2015 in Republic of Korea, according to EBOPS 6th. As a result, total service volume of export and import has increased in the last 10 years. Its volume, recently, accounts for 22% of total goods trade. Also the Korean Government can make a supporting policy and decide a supporting business in terms of service trade. Finally, we can find a mutual connectivity within 12 service businesses and between Service and Goods.

• Journal of Practical Engineering Education
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• v.15 no.1
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• pp.193-198
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• 2023

This paper analyzed the validity of exercise problems for each unit in Python programming education. Practice questions presented for each unit are presented through an online learning system, and each student uploads an answer code and is automatically graded. Data such as students' mid-term exam scores, final exam scores, and practice questions scores for each unit are collected through Python lecture that lasts for one semester. Through the collected data, it is possible to improve the exercise problems for each unit by analyzing the validity of the automatic scoring exercise problems. In this paper, Orange machine learning tool was used to analyze the validity of automatic scoring exercises. The data collected in the Python subject are analyzed and compared comprehensively by total, top, and bottom groups. From the prediction accuracy of the machine learning model that predicts the student's final grade from the Python unit-by-unit practice problem scores, the validity of the automatic scoring exercises for each unit was analyzed.

• Journal of Practical Engineering Education
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• v.14 no.3
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• pp.491-498
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• 2022

In this paper, as a liberal arts course for non-major students, a case study of recurrent neural network SW practice, which is essential for designing a basic recurrent neural network subject curriculum, was developed. The developed SW practice case focused on understanding the operation principle of the recurrent neural network, and used a spreadsheet to check the entire visualized operation process. The developed recurrent neural network practice case consisted of creating supervised text completion training data, implementing the input layer, hidden layer, state layer (context node), and output layer in sequence, and testing the performance of the recurrent neural network on text data. The recurrent neural network practice case developed in this paper automatically completes words with various numbers of characters. Using the proposed recurrent neural network practice case, it is possible to create an artificial intelligence SW practice case that automatically completes by expanding the maximum number of characters constituting Korean or English words in various ways. Therefore, it can be said that the utilization of this case of basic practice of recurrent neural network is high.

• Journal of Practical Engineering Education
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• v.16 no.3_spc
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• pp.283-290
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• 2024

Software education is an important subject in the era of forth industrial evolution generation, and the number of hours is gradually expanding in Korea's elementary and secondary curriculum, and universities have also opened software-related courses to take liberal arts mandatory regardless of major. The Ministry of Education presented elementary and secondary school programming achievement standards and emphasized the connection between prerequisite subjects as educational goals. Applicants for programming classes at H University also completed information classes in elementary and secondary courses, but many students were new to programming without taking related classes. Therefore, this study analyzed the data using the survey data and achievement scores of programming learners. As a result of the analysis, information classes completed in elementary and secondary courses were not linked to higher education courses at all, and improvements for problem solving were derived. This study is meaningful as a study for effective software education in higher education courses.

• Journal of the Korean Institute of Intelligent Systems
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• v.13 no.4
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• pp.403-408
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• 2003

A general meaning of caricaturing is that a representation, especially pictorial or literary, in which the subject's distinctive features or peculiarities are deliberately exaggerated to produce a comic or grotesque effect. In other words, a caricature is defined as a rough sketch(dessin) which is made by detecting features from human face and exaggerating or warping those. There have been developed many methods which can make a caricature image from human face using computer. In this paper, we propose a new caricaturing system. The system uses a real-time image or supplied image as an input image and deals with it on four processing steps and then creates a caricatured image finally. The four Processing steps are like that. The first step is detecting a face from input image. The second step is extracting special coordinate values as facial geometric information. The third step is deforming the face image using local warping method and the coordinate values acquired in the second step. In fourth step, the system transforms the deformed image into the better improved edge image using a fuzzy Sobel method and then creates a caricatured image finally. In this paper , we can realize a caricaturing system which is simpler than any other exiting systems in ways that create a caricatured image and does not need complex algorithms using many image processing methods like image recognition, transformation and edge detection.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.10 no.1
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• pp.37-45
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• 2016

The purpose of this study was to assess the intra-rater, inter-rater and test-retest reliability and validity of frontal plane lower extremity alignment estimated from a rasterstereographic method using ABW-Mapper. Eighteen subjects participated in this study. The S angle (stereographic angle-frontal plane lower extremity alignment estimated from a rasterstereographic method) in standing was measured throughout the two sessions with one week interval by two different readers. In the first session, a reader measured S angle twice per subject with a short break in-between. The Q-angle (quadriceps angle) was measured using a standard goniometer from a photography taken through digital camera with the participant standing in the same position as in the S angle measurement. The HKA(hip-knee-ankle) angle was measured from a computer based digital radiograph with the computerized measurement software. Reliability was tested using intraclass correlation coefficients(ICC). Validity was tested using a Pearson's correlation coefficient. Excellent intra-rater(ICC=0.956~0.974), inter-rater(ICC=0.962), test-retest reliability (ICC=0.945) were demonstrated. There were strong negative correlations between S angle and Q-angle (r=-0.739), and between S angle and HKA angle (r=-0.702). Therefore, the S angle measured using a rasterstereographic mapper may be used to as a preliminary or supplementary tool to evaluate and study LE alignment in the frontal plane in relation to HKA angle or Q-angle.

• Science of Emotion and Sensibility
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• v.12 no.2
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• pp.161-168
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• 2009

In this study, we have developed the patch type HAMS (Heart Activity Monitoring System) which is non-restricted, non-awarable and non-invasive. The module using wireless telecommunication to receive the ECG (electrocardiogram) signal at the computer has mobility which it easily monitors the heart activity of subjects in no time for long term at any time and places. We developed the small patch type electrode which can be attached on the chest. Also the reliability and moving artifact of ECG signal measured by this electrode have been verified. Using HAMS, we measured the HRV (Heart Rate Variability) parameters, the questionnaire evaluation for anxiety and stress and the amount of stress hormone (cotisol) to evaluate the stress effect in HRV on the same subject. As a result of comparing the values under non stressed and stressed condition, there was significant difference on many parameters. And the parameter highly related with stress on Pearson's Correlation Coefficient has been examined. These show that using HAMS is able to evaluate the function of autonomic nervous system. Therefore, we can predict heart problem in daily life by using HAMS. Also we expect that this module can be applied for more application as health monitoring system.

• Journal of Korea Entertainment Industry Association
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• v.14 no.1
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• pp.51-59
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• 2020

Although social interest is high in relation to the provision of disease codes to games, it is still insufficient to identify the damages caused by games. The purpose of this study is to examine the research trends related to game using of preschoolers to understand the implications of the precedent researches. According to the purpose, the research period, contents, types, data collection, statistical analysis, research/investigation subjects, and academic fields of the precedent researches were examined. The subject were 69 articles published in Korea from 2010 to 2019. As a result, first, a large number of researches related to preschoolers' game using were conducted in 2010-2011, 2014-2016, and the number has decreased sharply since 2017. Second, the contents of the study were mainly about the negative influences of the game and the program development. Third, quantitative and qualitative researches were conducted evenly. Fourth, the data collection methods was mostly questionnaire and other survey methods, and statistical analysis was mostly descriptive statistics, difference verification, and regression analysis. Fifth, the study subjects were focused on preschoolers, and there were many indirect investigation through parents and teachers. Sixth, the academic fields were largely divided into educational and game fields, and there was a distinct difference in the trend of research topics between the fields. Based on the results, this study aimed to provide basic information and data that can be the basis for further research on the game using and to suggest directions for future research.