• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.1
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• pp.94-100
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• 2015

Coronal mass ejection (CME) released due to solar flare explosion cause geomagnetic disturbance. The induced current by massive geomagnetic disturbance can cause damage to the transformer. The calculated geoelectric field is a major parameter of the geomagnetically induced current (GIC). The method applying a Fourier transform has a high accuracy but it needs all data measured for 24 hours. And the other method applying a integral equation can calculate in real time but it requires to check an accuracy. To reduce the gap between the calculated results of two methods, it adjusts the integration section. As a result, the correlation between two calculated geoelectric fields is high, and the event time and direction of the calculated current is the same as that of the measured current, and it's accuracy rate is above 92 percent.

• Journal of Digital Convergence
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• v.15 no.1
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• pp.1-9
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• 2017

The purpose of this study is to investigate the differences of the mobile phone overuse by gender and school levels. For this study, 565 middle and high school students in Gyeonggi province answered the self-report survey, 253 students were extracted as an overuse group, and the data were analyzed by one-way MANOVA. The results showed that 'daily disturbance' was a common major factor in gender and school level difference and 'school life disturbance', 'with draw' and 'tolerance' were added in school level difference. Based on the results, this study suggested users' characteristics such as gender and school level should be taken into prevention and treatment of mobile phone overuse.

• Research in Community and Public Health Nursing
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• v.13 no.3
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• pp.423-432
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• 2002

This study was conducted to test the validity of characteristics of family nursing phenomena in Korea identified in a previous study by Yoon, S. Y, et al. (1999). Data for this study were collected from 355 (first measurement 186, second measurement 169) nurses whose family nursing careers were more than one year using a cross sectional survey method. The distribution per one characteristic ranged between 0 to 5. The phenomena that had two or more characteristics and had a score of 3.0 points or more included disturbance in marital role', 'disturbance in family communication', 'inappropriate family coping', 'lack of family intimacy', 'unhealthy life style', 'deficit of financial management skill and support', 'inadequate care management sick member', and' inadequate home-making'. The essential characteristics of the 8 phenomena presented above included 27 items. Further studies on family nursing phenomena in Korea are needed to support the evidence through surveys of families in the field. A reconfirmation study, as well as qualitative research on the low validity of the characteristics, needs to be more performed in the future.

• Journal of Digital Convergence
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• v.16 no.7
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• pp.345-355
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• 2018

The purpose of this study was to investigate the convergence factors affecting of physical activity level on hemodialysis patients' depression, health-related quality of life and sleep disorders. The participants were 193 hemodialysis patients undergoing hemodialysis in five hospitals in two cities. Data were analyzed by technical statistics, correlation and hierarchical regression. The results showed that depression and physical activity were negatively correlated (r = -.259, p <.01), and physical and mental health related quality of life and physical activity correlated positively (R = .273, p <.01, r = .186, p <.01), respectively. Hierarchical regression analysis showed that the higher the quality of life related to physical health, the higher the level of physical activity of hemodialysis patients (${\beta}=.22$, p <.01). Therefore, it is required to develop an intervention program to improve health-related quality of life by improving the physical activity of hemodialysis patients.

• Journal of Wetlands Research
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• v.21 no.4
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• pp.290-297
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• 2019

The estuary is a transition zone where fresh water and salt water meet because the stream is connected to the open sea area. So estuaries have very high biodiversity and form a unique ecosystem. However, before the recognition of the ecological value of the estuaries, various damage and disturbances have been occurred so countermeasures are needed. The river master plan is acting as a disturbance factor. However, the river master plan has the public object such as water disaster defense, river function improvement, and national water resources management. Therefore, it is necessary to study the ways in which the opposite relationship of development and ecosystem protection coexist. In this study, the concept of environmental windows were used to estimate the low impact development duration. We expected that proposed method for low impact development duration estimation can be used as a basis and basic data to protected the ecosystem from development project and disturbance in the future.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.11
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• pp.1055-1065
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• 2009

In this study, stability analysis of boundary layers on airfoils is performed by using parabolized stability equations(PSE). Boundary layer edge conditions are obtained by compressible inviscid flow calculations. Mean velocity and temperature profiles of the laminar boundary layer are obtained by solving compressible boundary layer equations in generalized curvilinear coordinates with fourth order accuracy in the wall normal direction. Laminar mean flow profiles are used as input data for PSE to investigate growth rates of disturbances and stability characteristics. For the cases of boundary layer on NACA0012 and HSNLF(1)-0213 airfoils at Mach number 0.5, growth rates with respect to disturbance frequencies and profiles of disturbance amplitude are investigated. The effect of angle of attack on stability characteristics are examined at both upper and lower surfaces. The neutral stability curves, effect of Mach number and effect of airfoil section shapes are also analyzed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.431-437
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• 2017

In this study, based on the RPS algorithm, the application results to an electrically controlled suspension system using previewed road information are presented. Reducing the excessive vibration induced by a disturbance transmitted to the system and secure its stability is a major issue. In particular, in the automotive industry, the demand is constantly being raised. A typical external disturbance causing vibration and instability of a vehicle is an irregular roadway surface that contacts a running vehicle tire. Therefore, obtaining such profile information is an important process. The RPS algorithm using a multi sensor system was constructed and implemented in a real car. Through experimental work using the RPS system included non-contact type optical sensors, it could robustly reconstruct the road input profiles from the intermixed data onto the vehicle's dynamic motion while traveling at an uneven roadway surface. A controller with a preview control was designed in the framework of a semi-active suspension system based on the 7 degrees of freedom full vehicle model. The control performance of the system was evaluated through simulations and the results were compared with the passive vehicle condition. These results highlight the feasibility of the presented control frame.

• Journal of the Korean GEO-environmental Society
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• v.22 no.11
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• pp.23-29
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• 2021

Recently, ground subsidence has been steadily occurring mainly in downtown areas, threatening the safety of citizens. Under the road, various underground facilities such as water supply pipe, sewage pipe, and communication pipe are buried. Due to the aging of these underground facilities and the reckless development of the underground, it is acting as a cause of ground subsidence. Although there is a result of analyzing the risk of ground subsidence according to the deterioration of the existing pipeline, there is no result of analyzing the risk of ground subsidence using the density of pipelines indicating ground disturbance. Therefore, in this study, the density of the underground space was analyzed using the data of six types of representative underground pipelines in Seoul, and a study was conducted on whether there is a correlation with the ground subsidence. As a result, it was found that the density of underground facilities is high in the area where the ground subsidence occurred, indicating that the density of pipelines have an effect on the ground subsidence.

• Journal of the Korea Convergence Society
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• v.10 no.4
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• pp.65-71
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• 2019

The purpose of this study was to investigate the relationship between cardiovascular disease and periodontal disease. The subjects were 3,149 adults over 40 years of age using the third year National Health and Nutrition Examination Survey (2015). Data were analyzed using the SPSS 22.0 program. As a result, the relationship between cardiovascular disease and periodontal disease was 1.27 times higher in obesity group compared to normal group, when adjusted for disturbance variables (age, smoking status, drinking status, income) In hypertensive patients, the hypertension group had a 1.32-fold higher risk of periodontal disease when the disturbance variables (age, smoking status, drinking status, income) were adjusted compared to those without hypertension. Therefore, cardiovascular disease is associated with periodontal disease, and it can be used as a good basis for educational and preventive measures to reduce or prevent the incidence of cardiovascular disease and periodontal disease in the future.

• Journal of Korea Entertainment Industry Association
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• v.13 no.3
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• pp.203-211
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• 2019

The purpose of this study was to investigate the relations between sensory processing and sleep disturbances and to investigate the effect of sensory processing on sleep disorder in preschool children with developmental disorder. This study was conducted for 110 children with developmental disorder in developmental clinic and rehabilitation hospital in Gwang Ju from June to August, 2017. The final 109 data were analyzed. Sensory processing and Sleep disturbances were measured using the Shortened sensory profile(SSP) and Korean-the Children's Sleep Habits Questionnaire(K-CSHQ). Statistical analysis was performed using descriptive analysis, Pearson correlation analysis, and multiple regression analysis were performed. Children with developmental disorder had problems with sensory processing and sleep habits. Sensory processing was related to sleep habit and most important factors of sensory processing influencing sleep was taste/olfactory sensitivity, auditory filtering. Conclusion: In order to help children with developmental disorder with sleep problem, it is necessary to consider the sensory processing especially taste/olfactory sensitivity, auditory filtering.