• Journal of Industrial Convergence
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• v.19 no.1
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• pp.109-116
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• 2021

The purpose of this study was to determine the effects of asthma, allergic rhinitis, atopic dermatitis, and high intensity exercise on depressive symptoms and suicidal ideation in adolescents. This is a secondary data analysis study using 15th Korean Children and Youth Panel Survey. Data analysis was performed by chi-square and logistic regression analysis using SPSS 22.0. As a result, there were differences in allergic diseases, high-intensity exercise, smoking experience, and drinking experience in both depressive symptoms and suicidal ideation. After adjusting for smoking experience and alcohol experience, asthma, allergic rhinitis, and atopic dermatitis were influencing factor for depression symptoms(OR:1.16, 95% CI:1.07-1.26; OR:1.16, 95% CI:1.11-1.21; OR:1.17, 95% CI:1.11-1.23) and for suicidal ideation(OR:1.32, 95% CI:1.20-1.47; OR:1.22, 95% CI:1.15-1.29; OR:1.21, 95% CI:1.14-1.29). However, high intensity exercise had decreased depressive symptoms and suicidal ideation(OR:0.90, 95% CI:0.86-0.94; OR:0.85, 95% CI:0.80-0.90). As a result of this study, it was found that allergic diseases and high-intensity exercise had a great effect on mental health in adolescents, and we may use it as basic data for prevention and research related to the mental health of adolescent.

• Journal of the Korea Convergence Society
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• v.13 no.4
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• pp.553-560
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• 2022

This study was conducted to identify the factors affecting the quality of life of women over 10 years after menopause using data from 2014 to 2019 of the National Health and Nutrition Examination Survey. The subjects were 6,330. The data were analyzed by frequency analysis, t-test and multiple regression analysis using SPSS 25. As a result of the study, the factors affecting the health-related quality of life of women 10 years after menopause were age(F=30.625, p<.001), educational level(F=20.106, p<.001), perceived health status(F=187.925, p<.001, activity limitation(t=201.051, p<.001), arthritis(t=91.131, p<.001), osteoporosis(t=4.709, p=.030), hand grip strength(t=22.151, p<.001), perceived stress(F=32.775, p<.001), and depression(t=20.117, p<.001). The factors accounted for 35.1%(F=110.393, p<.001). In order to improve the quality of life of postmenopausal women, it is necessary to continuously evaluate and improve the factors affecting the quality of life from the early menopause.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.40 no.4
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• pp.293-304
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• 2022

In this study, to analyze the effect of buildings on the image co-registration performance, co-registration results are compared according to the presence or absence of matching points extracted from buildings. To remove the matching points extracted from buildings, a building mask generated by extracting building objects from the digital topographic map was used. In addition, matching points extraction performance and image co-registration accuracy were analyzed according to the magnitude of the convergence angle. Image co-registration results were compared by applying the affine and piecewise linear transformation models, respectively. According to the experimental results, the affine transformation model showed an overall improvement in accuracy after removing the matching points extracted from buildings. On the other hand, the piecewise linear transformation model improved the accuracy at the checkpoints including the surrounding buildings, but the accuracy improvement was not significant at checkpoints in the flat area without the existence of buildings. In addition, when the piecewise linear transformation model was applied, stable accuracy of less than 2 pixels was derived from images with a convergence angle of 20° or less.

• Journal of Korea Water Resources Association
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• v.54 no.11
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• pp.933-942
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• 2021

The surface image velocimetry was developed to measure river flow velocity safely and effectively in flood season. There are a couple of methods in the surface image velocimetry. Among them the spatio-temporal image velocimetry is in the spotlight, since it can estimate mean velocity for a period of time. For the spatio-temporal image velocimetry analyzes a series of images all at once, it can reduce analyzing time so much. It, however, has a little drawback to find out the main flow direction. If the direction of spatio-temporal image does not coincide to the main flow direction, it may cause singnificant error in velocity. The present study aims to propose a new method to find out the main flow direction by using a fast Fourier transform(FFT) to a spatio-temporal (image) volume, which were constructed by accumulating the river surface images along the time direction. The method consists of two steps; the first step for finding main flow direction in space image and the second step for calculating the velocity magnitude in main flow direction in spatio-temporal image. In the first step a time-accumulated image was made from the spatio-temporal volume along the time direction. We analyzed this time-accumulated image by using FFT and figured out the main flow direction from the transformed image. Then a spatio-temporal image in main flow direction was extracted from the spatio-temporal volume. Once again, the spatio-temporal image was analyzed by FFT and velocity magnitudes were calculated from the transformed image. The proposed method was applied to a series of artificial images for error analysis. It was shown that the proposed method could analyze two-dimensional flow field with fairly good accuracy.

• Journal of Industrial Convergence
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• v.20 no.11
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• pp.49-55
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• 2022

This study is a secondary data analysis study to confirm the difference in responses to psychological and supportive factors of severely disabled according to proxy responses using the National Survey of the Disabled 2020. 738,169 people with severe disabilities who were 19 years of age or older, whose main disability was not an intellectual disability, were analyzed. χ²-test and t-test were performed using IBM SPSS Statistics 26.0. As a result of the study, the proxy response was more negative in sadness or hopelessness (χ²=952.20, p<.001), suicidal ideation (χ²=369.45, p<.001), and subjective health status (t=30.61, p<.001). And the proxy respondent answered that they need more support from others for daily life (t=209.43, p<.001) and have many difficulties in communication when using medical services (t=41.74, p<.001). When using a proxy response, the researcher should clearly state the point of view that the proxy respondent should take, and interpret the results considering that proxy response may be affected by various factors.

• Communications of Mathematical Education
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• v.37 no.1
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• pp.65-84
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• 2023

The method of Lagrange multipliers, one of the most fundamental algorithms for solving equality constrained optimization problems, has been widely used in basic mathematics for artificial intelligence (AI), linear algebra, optimization theory, and control theory. This method is an important tool that connects calculus and linear algebra. It is actively used in artificial intelligence algorithms including principal component analysis (PCA). Therefore, it is desired that instructors motivate students who first encounter this method in college calculus. In this paper, we provide an integrated perspective for instructors to teach the method of Lagrange multipliers effectively. First, we provide visualization materials and Python-based code, helping to understand the principle of this method. Second, we give a full explanation on the relation between Lagrange multiplier and eigenvalues of a matrix. Third, we give the proof of the first-order optimality condition, which is a fundamental of the method of Lagrange multipliers, and briefly introduce the generalized version of it in optimization. Finally, we give an example of PCA analysis on a real data. These materials can be utilized in class for teaching of the method of Lagrange multipliers.

• Journal of Korea Entertainment Industry Association
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• v.13 no.5
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• pp.127-138
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• 2019

This study was a secondary data analysis using statistics from the 13th (2017) Korea Youth Risk Behavior Web-based Survey (KYRBS) to investigate the relationship between health behaviors and physical activity among Korean adolescents. A total of 62,276 adolescents in middle and high schools enrolled in this study. Physical activity utilized moderate and vigorous physical activity variables. Health behaviors used smoking, drinking, eating, sedentary behavior, and sleep duration variables. Statistical analyses were performed applying complex sample analysis method. Chi-square tests were used to compare physical activity according to health behaviors. Multivariate multinomial logistic regression analyses were conducted to examine the relationship between health behaviors and physical activity, adjusted for general characteristics. Current smoking and current drinking were associated with high levels of moderate and vigorous physical activity. Consuming fruits≥1 times/day, vegetables≥3 times/day, and sweet drinks≥3 times/week were associated with high levels of moderate and vigorous physical activity. Eating breakfast≥5 times/week was associated with high levels of moderate physical activity, but not with vigorous physical activity. Sedentary behavior≥2 hour/day was associated with low levels of moderate and vigorous physical activity. Sleep duration<7 hour/day was associated with high levels of moderate physical activity and low levels of vigorous physical activity. These findings suggest that since there is an interrelationship between health behaviors and physical activity among adolescents, intervention programs aiming at promoting physical activity and healthy lifestyles should consider a multiple behavior approach rather than an individual behavior approach.

• Resources Recycling
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• v.32 no.6
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• pp.67-78
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• 2023

The rare metals used as raw materials in high-tech industries undergo changes in demand structures and supply chains following domestic industrial structural shifts and technological advancements, exhibiting high price volatility. Therefore, it is necessary to periodically analyze changes in the demand structures of rare metals. Since domestic demand for most rare metals relies on imports in Korea, the changes in domestic demand for rare metals can be identified by analyzing changes in their trade structure. In the present study, we analyze the changes in trade volume, trade growth rate, trade rankings, and trading countries from 2000 to 2022 for 35 rare metals, categorized into five types-ores, metals, alloys, compounds, and scrap. The trade of the raw materials of rare metals in Korea has generally increased since the 2000s, except for a significant decline in 2009 and 2016. The total trade volume, encompassing both exports and imports, has increased by approximately tenfold in 2022 compared to 2001. Until the mid-2010s, the trade of the raw materials of rare metals was primarily focused on those used in steel-manufacturing such as silicon, nickel, chrome, molybdenum, manganese, and others. However, after that period, there has been an increase in the trade of platinum group metals like palladium, rhodium, platinum, and the raw materials of rare metals for secondary battery-manufacturing such as lithium and cobalt. Particularly in 2022, lithium has become the largest share in trade of the raw materials of rare metals in Korea, due to the price surge and increase in demand.

• Studies on Life and Culture
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• v.52
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• pp.129-152
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• 2019

This study aims to identify hinderance factors impeding a invigoration of treatment and protection system for drug abusers and provide an alternative plan to solve it from a viewpoint of alcoholism treatment experts. To achieve the goal, a research and service report on treatment and protection work was secondarily obtained and 58 cases of alcoholism treatment experts were extracted and analysed. The collected data were analysed with deducted content analysis proposed by Elo and Kynga(2008), and hinderance factors impeding a invigoration of treatment and protection system for drug abusers were discovered by 8 categories including 'cognition of a patient problem', 'condition of a patient problem', 'worker problem', 'agency problem', 'treatment program problem', 'budget problem', 'selection of test object problem', 'system problem'. According to the result, alternatives including plenty information and prior education for a recipient, a management on a patient's supportive system, an operation of independent hospital ward for drug, a provision of an incentive pay on treatment experts and agencies, an establishment of rehabilitation institute, a development of systematic program offering treatment, rehabilitation and self support, a budget increase and effective ways to utilize, strengthening a communication between the prosecution and treatment ad protection institutions, an assurance of enough treatment and protection period, an introduction of mandatory treatment system and a development of integrated manual for workers were suggested.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.11
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• pp.2094-2105
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• 1994

This paper contains a Hough transform based projection method derived from Radon transform for tracking dim unresolved(sub-pixel) moving targets that move along straight line parths across a time sequential image data. In contrast to several recently presented Hough transform methods using a compressed image referred to as the track map our proposed technique utilizing a set of projections taken along arbitrary orientations effectively increases the changes of target detection, and creates a robust track estimation environment by incorporating all the available knowledge obtained from the projections. Moreover, in order to quantitatively assess the estimation capability of the projection-based Hough transform algorithm, the analytical bounds on the Hough space parameter errors introduced by image space noise contamination are derived. The simulation yielded promising results of estimating the track parameters even under low signal to noise rations when our technique was tested against the time sequential sets of real infrared image data referred to as the HiCamps.