• Journal of Advanced Navigation Technology
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• v.27 no.6
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• pp.888-896
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• 2023

When an aircraft is landing, it is expected that the aircraft will follow a specified approach procedure and then land at the airport. However, depending on the airport situation, neighbouring aircraft or the instructions of the air traffic controller, there can be a deviation from the specified approach. Detecting aircraft approach patterns is necessary for traffic flow and flight safety, and this paper suggests clustering techniques to identify aircraft patterns in the approach segment. The Gaussian Mixture Model (GMM), one of the machine learning techniques, is used to cluster the trajectories of aircraft, and ADS-B data from aircraft landing at the Gimhae airport in 2019 are used. The aircraft trajectories are clustered on the plane, and a total of 86 approach trajectory patterns are extracted using the centroid value of each cluster. Considering the correlation between the approach procedure pattern and overshoots, the distribution of overshoots is calculated.

• Journal of the Health Care and Life Science
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• v.10 no.2
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• pp.361-367
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• 2022

This study provides several methods to minimize dead zone and to detect missing person using combined DRONE and AI especially called 4 th Industrial Revolution. That is composed of image acquisition for a person who is in needed of support. The procedure is DRONE that is made of image acquisition and transfer system. after that can be shown GPS information. Currently representative AI algorithm is YOLO (You Only Look Once) that can be adopted to find manikin or real image by learning with dataset. The output was reached in reliable and efficient results. As the trends of DRONE is expanded widely that will provide various roll. This paper was composed of three parts. the first is DRONE specification, the second is the definition of AI and procedures, the third is the methods of image acquisition using DRONE, the last is the future of DRONE with AI.

• Journal of the Korean Society for information Management
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• v.41 no.3
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• pp.171-203
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• 2024

The purpose of this study is to analyze the factors that influence youth reading habits through exploratory data analysis of various reading variables. Using data from the Korean Children and Youth Panel Survey, we divided participants into a reading group and a non-reading group and analyzed the factors influencing reading habits through a t-test that compared the mean differences between the two groups. The results are as follows: The reading group showed higher scores than the non-reading group in learning-related factors such as study time and academic engagement, positive emotional factors, career-related factors, and social activity factors such as club participation and volunteering. On the other hand, the non-reading group scored higher in key factors such as academic helplessness, emotional problems like aggression and depression, and experiences of delinquent behavior. Additionally, this study suggests further research topics such as the relationship between reading and interactions with parents, cooperation as a social emotion, and physical activity, areas that have not been deeply explored in previous studies.

• Geophysics and Geophysical Exploration
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• v.21 no.3
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• pp.150-161
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• 2018

Recently, unmanned aircraft EM (electromagnetic) survey based on ICT (Information and Communication Technology) has been widely utilized because of the efficiency in regional survey. We performed the theoretical study on the unmanned airship EM system developed by KIGAM (Korea Institute of Geoscience and Mineral resources) as part of the practical application of unmanned aircraft EM survey. Since this system has different configurations of transmitting and receiving loops compared to the conventional aircraft EM systems, a new technique is required for the appropriate interpretation of measured responses. Therefore, we proposed a method to calculate the EM field for the arbitrary shaped transmitter and verified its validity through the comparison with analytic solution for circular loop. In addition, to simulate the magnetic responses by three-dimensionally (3D) distributed anomalies, we have adapted our algorithm to 3D frequency-domain EM modeling algorithm based on the edge-FEM (finite element method). Though the analysis on magnetic field responses from a subsurface anomaly, it was found that the response decreases as the depth of the anomaly increases or the flight altitude increases. Also, it was confirmed that the response became smaller as the resistivity of the anomaly increases. However, a nonlinear trend of the out-of-phase component is shown depending on the depth of the anomaly and the used frequency, that makes it difficult to apply simple analysis based on the mapping of the magnitude of the responses and can cause the non-uniqueness problem in calculating the apparent resistivity. Thus, it is a prerequisite to analyze the appropriate frequency band and flight altitude considering the purpose of the survey and the site conditions when conducting a survey using the unmanned aircraft EM system.

• Journal of Korea Water Resources Association
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• v.54 no.11
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• pp.903-913
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• 2021

In the flood season, the measurement of the river discharge has many restrictions due to reasons such as budget, manpower, safety, convenience in measurement and so on. In particular, when heavy rain events occur due to typhoons, etc., it is difficult to measure the amount of flood due to the above problems. In order to improve this problem, in this study, a method was developed that can measure the river discharge in a flood season simply and safely in a short time with minimal manpower by combining the functions of a drone and a surface velocity doppler radar. To overcome the mechanical limitations of drones caused by weather issues such as wind and rainfall derived from the measurement of the river discharge using the conventional drone, we developed a drone with P56 grade dustproof and waterproof performance, stable flight capability at a wind speed of up to 36 km/h, and a payload weight of up to 10 kg. Further, to eliminate vibration which is the most important constraint factor in the measurement with a surface velocity doppler radar, a damper plate was developed as a device that combines a drone and a surface velocity Doppler radar. The velocity meter DSVM (Dron and Surface Veloctity Meter using doppler radar) that combines the flight equipment with the velocity meter was produced. The error of ±3.5% occurred as a result of measuring the river discharge using DSVM at the point of Geumsan-gun (Hwangpunggyo) located at Bonghwang stream (the first tributary stream of the Geum River). In addition, when calculating the mean velocity from the measured surface velocity, the measurement was performed using ADCP simultaneously to improve accuracy, and the mean velocity conversion factor (0.92) was calculated by comparing the mean velocity. In this study, the discharge measured by combining a drone and a surface velocity meter was compared with the discharge measured using ADCP and floats, so that the application and utility of DSVM was confirmed.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.6 no.1
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• pp.56-64
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• 1995

Family is a primary unit of the major socialization processing for children. Parents among the family members are one of the most important figures from whom the child and adolescent acquire a wide variety of behavior patterns, attitudes, values and norms. An organization of family members product family structural functioning. Abnormal family structure is one of the most important reference models in the learning of antisocial patterns of behavior. Therefore incest and child sexual abuse including spouse abuse, elderly abuse, and neglect occurs in the abnormal family structural setting. In particular, incest, a specific form of sexual abuse, was once thought to be a phenomenon of great rarity, but our clinical experiences, especially over the past decade, have made us aware that incest and child sexual abuse is not rare case and on the increasing trend. Therefore, the aim of this study was to determine the family problem and dynamics of incest family, and character pattern of post-incest adolescent victim in Korea. A total of 1,838 adolescents from middle and high school(1,237) and juvenile correctional institute(601) were studied, sampled from Korean student population and adolescent delinquent population confined in juvenile correctional institutes, using proportional stratified random sampling method. The subjects' ages ranged from 12 to 21 years. Data were collected through questionnaire survey. Data analysis was done by IBM PC of Behavior Science Center at the Korea university, using SAS program. Statistical methods employed were Chi-square, principal component analysis and t-test etc. The results of this study were as follows ; 1) Of 1,071 subjects, 40(3.7%) reported incest experiences(sibling incest : 1.6% ; another type of incest : 2.1%) in their family setting. 2) The character pattern of post-incest adolescent victim was more socially maladjusted, immature, impulsive, rigid, anxious and dependent than non-incest adolescent. Also they showed some problem in academic performance and their assertiveness. 3) The other family members of incest family revealed more psychological and behavioral problem such as depression, alcoholism, psychotic disorder and criminal act than the non-incest family, even though there is no evidence of the context between them. 4) The family dynamics of incest family tended to be dysfunctional trend, as compared with non-incest family. It showed that the psychological instability of family member, parental rejection toward their children, coldness and indifference among family member and marital discordance between the parents had significant correlation with incest.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.9 s.112
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• pp.900-912
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• 2006

A GPS receiving antenna installed in the missile's warhead is designed and fabricated at a center frequency 1.575 GHz. The circular shaped antenna is installed in the middle of the warhead where the antenna's patch and the ground plane are connected with a hollow cylindrical shaped short pin. Using the dual feeding and phase difference method, an omni-directional radiation pattern which direction is normal to the missile's axis(H-plane) is obtained. The optimized diameters of the circular patch and the cylindrical ring typed shorting pin of the GPS receiving antenna which use the FR4.material(dielectric constant $\varepsilon_r=4.6$) are 59.5 mm and 14 mm, respectively. The cylindrical body with diameter 100 mm and height 500 mm is attached to the lower part of the warhead in order to complete the missile figure. The radiation patterns are measured by changing the angle and phase between the dual feeding points. When the phase difference of dual feeding is $100^{\circ}$ and the angle between the dual feeding points is $100^{\circ}$, the nearly omni-directional radiation pattern in the H-plane is obtained. In this case, the antenna gain is -5.55 dBd and the relative level difference between the maximum and the minimum radiation intensity is 3.98 dB.

• Korean Journal of Social Welfare
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• v.38
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• pp.153-179
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• 1999

Despite the enforcement of minimum legal drinking age of 18 years of age since 1997, alcohol experimentation among Korean youth is believed to be greater than ever before. The use of alcohol jeopardizes physical, mental, and social development during a person's formative years, thereby endangering successful transitions from adolescent to adulthood. Even infrequent use of alcohol may result in intoxication and acute consequences, especially among youth, who may have low tolerance due to their smaller body size and may lack experience with the effects of alcohol. Using self-report questionnaire data collected from 1,697 highschool students nation-wide, the drinking behavior among Korean high school students and the relation between adolescents' alcohol expectancy and adolescent alcohol use patterns were examined. Results indicated that gender and the type of school(academic or vocational) were significant effects on the drinking behavior(drinking frequency, experience of drunkenness, the amount of alcohol consumed, experience of binge drinking and that of problems due to drinking). Male students than female students, and students of vocational schools rather than those of academic high schools reported more alcohol experimentation. Also, positive alcohol expectancy proved to have a significant relation with alcohol use among high-school students. That is, students who reported to think alcohol would have a positive effect on socializing, aggressiveness, relaxation of tensions, and enforcing sexual ability tended to drink more, to experience more binge drinking and more drinking problems. Variables of gender and the type of school also were found to have significant effects on alcohol expectancy. Males and students of vocational school held ideas of positive outcomes on drinking than others. Implications for further study on developing prevention programs are presented.

• The Journal of the Korea Contents Association
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• v.19 no.7
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• pp.546-558
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• 2019

Health inequality means health gaps that can be affected adverse effects to the vulnerable groups in a society. Many scholars argue that it is needed social interventions to reduce health gaps between the vulnerable and the privileged in a society, because social inequalities can be caused and resulted health inequality among them. In this context, this article introduces Korean out of school children health check-up as part of the policies to reduce health inequality in the society. For a long time, many out of school children have been alienated from the national health checkup systems. That means they are not only marginalized groups in Korean society, but also excluded from the benefits of health promotion and health management. Many runaway youths are struggling to live by themselves, who are escaped from their families and they don't have enough resources to keep their health. They are also young and low waged workers who are expelled to the streets, while they don't have any support and protection from the communities. Out of school children health checkup has been conducted to the adolescents who stay in the shelters or study in alternative schools. To get meaningful results as the health inequality reduction policy, it is needed to expand out of children health checkup to the runaway teenagers.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.5
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• pp.627-635
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• 2019

A programmable drone is a drone developed not only to experience the basic principles of flight but also to control drones through Arduino-based programming. Due to the nature of the training drones, the main users are students who are inexperienced in controlling the drones, which often cause frequent collisions with external objects, resulting in high damage to the drones' frame. In this study, the structural stability of the drone was evaluated by means of a structural dynamics based collision simulation for educational drone frame. Collision simulations were performed on three cases according to the impact angle of $0^{\circ}$, $+15^{\circ}$ and $-15^{\circ}$, using an analytical model with approximately 240,000 tetrahedron elements. Using ANSYS LS-DYNA, which provides excellent functions for the simulation of the dynamic behavior of three-dimensional structures, the stress distribution and strain generated on the drone upper, the drone lower, and the ring assembly were analyzed when the drones collided against the wall at a rate of 4 m/s. Safety factors resulting from the equivalent stress and the yield strain were calculated in the range of 0.72 to 2.64 and 1.72 to 26.67, respectively. To ensure structural stability for areas where stress exceeds yield strain and ultimate strain according to material properties, the design reinforcement is presented.