• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.1
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• pp.129-137
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• 2016

In the present study we verified performance of feed-forward control algorithm using short term prediction of ship motion information by taking advantage of developed numerical simulation model of FPSO motion. Up until now, various studies have been conducted about thrust control and allocation for dynamic positioning systems maintaining positions of ships or marine structures in diverse sea environmental conditions. In the existing studies, however, the dynamic positioning systems consist of only feedback control gains using a motion of vessel derived from environmental loads such as current, wind and wave. This study addresses dynamic positioning systems which have feedforward control gain derived from forecasted value of a motion of vessel occurred by current, wind and wave force. In this study, the future motion of vessel is forecasted via Brown's Exponential Smoothing after calculating the vessel motion via a selected mathematical model, and the control force for maintaining the position and heading angle of a vessel is decided by the feedback controller and the feedforward controller using PID theory and forecasted vessel motion respectively. For the allocation of thrusts, the Lagrange Multiplier Method is exploited. By constructing a simulation code for a dynamic positioning system of FPSO, the performance of feedforward control system which has feedback controller and feedforward controller was assessed. According to the result of this study, in case of using feedforward control system, it shows smaller maximum thrust power than using conventional feedback control system.

• Journal of the Institute of Convergence Signal Processing
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• v.21 no.3
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• pp.107-112
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• 2020

With the importance of creative learning highly valued, the demand for education in early childhood and adolescence has been increasing in recent years, but simple memorization-oriented and classical teaching methods tend not to prove high effectiveness in terms of learner-centeredness. Students who study static at their desks for a long time do not prefer boring classical learning methods, and there is also a lack of educational methods and educational content that conforms to the convergence education trend in the actual educational field. Therefore, this study has created a system that allows students to exercise and learn at the same time through a fun and familiar approach, and implement educational content through activation of brain plasticity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.483-489
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• 2018

Driving behaviors are reported to be vulnerable to safe driving in unexpected situations or driving in the city due to deterioration of physical and cognitive functions in elderly drivers. The purpose of this study was to investigate the difference in driving behaviors according to age of self-drivers and to identify changes in physical function related to driving caused by normal aging. The subjects of the study included 75 healthy adults (21 persons aged 20-39 years, 40 persons 40-64 years, 14 persons 65 years old) who were self-driving and possessed a driver's license. Data included sex, dominant hand, medication, exercise, age, and driving time obtained by a self-reported questionnaire. In addition, this study measured steering, acceleration and braking using a Driver Test Station. Results of the study showed there was no significant difference in power test according to age group, but the total time of the timer test and the emergency brake test significantly differed according to age. The timer test and emergency brake test were completed fastest in young adults between 20 and 39 years old and completed slowest in elderly people 65 years old or over. Based on our study results, it is suggested that normal aging affects the perceptual-cognitive processes associated with driving behaviors.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.2179-2183
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• 2008

지금까지 분포형 모형 개발에 대한 많은 노력이 있음에도 불구하고 여러 제약사항들에 의해 잠재력을 보여주는 정도로 활용되어 왔으나, 최근 급속도로 발전하는 컴퓨터의 계산능력, DEM 등 디지털정보의 구축이 진행되어 오고 있고, GIS 및 인공위성 영상기법의 발달로 공간적인 비균질성을 고려하여 유출과정에서 운동역학적인 이론을 기반으로 물의 흐름을 수리학적으로 추적해 나가는 물리적기반의 분포형 유출모형의 활용도가 높아지고 있다. 본 모형개발에 있어 이론적 배경이 된 모형은 1998년부터 일본 교토대학 방재연구소 코지리 연구실에서 개발 중인 Hydro-BEAM으로 유역 물순환의 건전성을 평가하기 위하여 장기간의 유역 내 유량, 수질을 시계열 및 공간적으로 파악하여 유역의 영향평가를 위해 개발된 물리적 기반의 격자구조를 가진 분포형 장기유출 모형이다. 유출량 계산은 유역내 수평 유출량산정 모듈로서 평면 분포형의 격자형을, 연직 분포형으로는 $A{\sim}B$층의 수평유출량은 하천으로 유입하고, C층은 하천유량에 영향을 미치지 않는 지하수층으로 가정하는 다층모형을 이용해서 A층, 지표 및 하도흐름은 운동파 법(kinematic wave)으로, $B{\sim}C$층의 유출량은 선형저류법으로 계산하는 모형이다. 본 연구에서는 격자흐름방향을 4방향에서 8방향으로 개선하였고, 모형의 각종 수문매개변수들을 GIS와 연계하여 직접 입력할 수 있도록 하였으며, 물리적기반의 침투과정을 모의할 수 있도록 Green & Ampt모듈을 추가하고, 향후 레이더 강우 및 수치예보강우의 홍수유출예측을 염두에 두고 격자강우량을 활용할 수 있도록 하는 등 홍수유출해석을 위한 분포형 강우-유출모형으로 개선 하였고, 이를 남강댐유역에 적용해 봄으로써 모형의 적용성을 검토해 보고자 하였다. 홍수기동안의 지표흐름과 지표하 흐름의 시간적 변화와 공간적 분포를 모의할 수 있었으며, 전처리과정으로서 ArcGIS 혹은 ArcView등의 GIS 프로그램을 이용하여 모형에 필요한 ASCII형태의 입력 매개 변수 자료들을 가공하였다. 또한 후처리과정으로서 모형의 수행결과인 유역내의 유출량 분포 등을 GIS상에서 나타낼 수 있도록 ASCII형태로 출력하도록 구성하였다. 남강댐유역을 대상으로 유역을 500m의 정방형 격자로 분할하고 수계망을 통하여 유역 출구까지 운동파이론에 의해 추적 계산하였으며, 수문곡선 비교결과 재현성 높은 결과를 보여주었다. 모형의 정확성 및 실용성에 대한 보다 정확한 평가를 위해서는 향후 다양한 강우 사상 혹은 다양한 크기의 유역에 대한 유출량의 재현성 및 매개변수 등에 검증이 이루어져야 할 것이다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.3
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• pp.257-265
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• 2016

In this study, an optimal design for motor-driven track type traveling system applied into high clearance working machineries in orchard is proposed. Tractive performance and hill climbing ability were predicted and evaluated for the optimal motor traveling system by taking into account of soil characteristics in orchard utilizing the high clearance working machineries. Design criteria for tractive performance were based on the traction force calculated from tractive effort subtracted by motion resistance, while hill climbing ability had its design criteria that fulfill the climbing 20% slope ground at a speed of 3km/h. Based on the evaluation results of traction and climbing ability, two DC48V, 4500rpm, 1.6kW AC motors were independently applied to both left and right side of orbits; each motor is designed to transmit power on driving sprocket of track type traveling system via 50:1 reduction gear ratio. The motor-driven track type traveling system developed in the study found to have 396 kgf of tractive force, which is 12.5% higher than climbing resistance at orchard soil having 20% slope ground (352 kgf), demonstrating sufficient tractive performance and hill climbing ability.

• The Journal of the Korea Contents Association
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• v.14 no.7
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• pp.346-355
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• 2014

This study was to investigate basic level of physical activity test that reflects activity of daily living(ADL) for institutionalized elderly women. The subjects were 105 elderly women over than 65 years living in long-term care facilities located in Daejeon and Chungnam. The measured eight items related to ADL were tested and the data was analyzed by descriptive statistics, one-way ANOVA, factors analysis and correlation. The results were statistically significant differences. Among eight test items, two factors(muscle strength and mobility) were extracted by principal component factor analysis(PCA). The two factors are appropriate domains for assessment of basic physical activity of institutionalized elderly women. By using Pearson's correlation, between two factors and age, the first principal component scores were significantly decreased with age increasing. Degradation of ADL must be prevented for institutionalized elderly women through maintain muscle strength and mobility.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.1
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• pp.78-84
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• 2010

This study was to designed to investigate the effects of nutrition education and exercise program for overweight or obese female adults, and also emphasize the necessity of a proper nutrition education. The anthropometric characteristics, nutritional intake, eating habit, and hematological index, physical examination were measured before and after program. Considering the time schedule of the subjects, the exercise program was divided into 3 sessions (morning, afternoon, and evening) and the subjects performed swimming and weight training for 4 weeks. The subjects were overweight or obese women, with an average age and height of each 46.1 and 156.3 cm. The weight and BMI were decreased significantly after nutrition education and exercise program. The back region of front arm (p<0.001), infrascapular region (p<0.001), body fat (p<0.001) were significantly decreased, and grasping power (p<0.01), back muscle power (p<0.001) were significantly increased after nutritional and exercise program. Total triglyceride level and fasting blood glucose (p<0.001) were decreased significantly after program. The intakes of vitamin D and vitamin $B_1$ were significantly changed after nutrition and exercise program. As for eating behavior and nutritional knowledge evaluation after program, the average score increased significantly (p<0.001). The results of this study show that this nutrition and exercise program can be an effective approach to improve their hematological index and nutritional and health status.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.221-227
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• 2016

This study was conducted to identify sensory processing factors that affect motor and process skills of children with cerebral palsy. A total of 36 children with cerebral palsy who attended at the J pediatric development center and the N rehabilitation hospital in Seoul participated. Pearson's correlation coefficients were used to test the relationship between motor skills, process skills and sensory processing abilities of children. Moreover, hierarchical multiple regression was used to identify the sensory processing factors influencing motor and process skills. Motor skills of children with cerebral palsy were correlated with auditory filtering, low energy/weakness, and visual/auditory sensitivity of sensory processing items, whereas process skills were correlated with tactile sensitivity and taste/smell sensitivity. The hierarchical regression model for motor skills revealed movement sensitivity, auditory filtering, and low energy/weakness as significant factors influencing sensory processing items. However, no factors were shown to influence process skills. The results of this study will be useful as a basic resource for rehabilitation of children with cerebral palsy. However, further studies evaluating a larger population should be conducted to verify the results presented herein.

• The Journal of the Korea Contents Association
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• v.10 no.3
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• pp.232-240
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• 2010

This study is to look into the effectiveness of fall-preventive occupational therapy of elderly by clarifying the influence of occupational therapy applied to female elderly in the community upon balance ability. A 6-week occupational therapy program including both training and exercise for prevention of fall down was applied by dividing into 13 persons of experimental group and 13 persons of control group for female elderly aged more than 65 years who were capable of independence gait and have not taken any drug to adversely affect balance. For balance ability assessment, the Berg balance scale and the Tetrax fall index were used. The Berg balance scale in experimental group was shown to be 48.38 to 50.69 through the 6-week program, indicating changes in significance level(p=.017). The Tetrax fall index in experimental group was shown to be 46.77 to 35.54 through the 6-week program(p=.000). Changes in significance level were not found for both the Berg balance scale and the Tetrax fall index in control group. As seen from the results of this study, it is found that 6-week application of the fall-preventive occupational therapy program including fall prevention training and exercise was effective for promotion of elderly's balance ability, and further studies just on the effect of fall prevention training are required to be made.

• The Journal of Korean Academy of Sensory Integration
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• v.19 no.1
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• pp.69-82
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• 2021

Objective : This recent work intended to provide basic information for researchers and practitioners related to occupational therapy about Developmental Coordination Disorder (DCD) in South Korea. The previous research of screening DCD and the effects of intervention programs were reviewed. Methods : Peer-reviewed papers relating to DCD and published in Korea from January 1990 to December 2020 were systematically reviewed. The search terms "developmental coordination disorder," "development coordination," and "developmental coordination" were used to identify previous Korean research in this area from three representation database, the Research Information Sharing Service, Korean Studies Information Service System, and Google Scholar. We found a total of 4,878 articles identified through the three search engines and selected seventeen articles for analysis after removing those that corresponded to the overlapping or exclusion criteria. We adopted "the conceptual model" to analyze the selected articles about DCD assessment and intervention. Results : We found that twelve of the 17 studies showed the qualitative level of Level 2 using non-randomized approach between the two groups. The Movement Assessment Battery for Children and its second edition were the most frequently used tools in assessing children for DCD. Among the intervention studies, the eight articles (47%) were adopted a dynamic systems approach; a normative functional skill framework and cognitive neuroscience were each used in 18% of the pieces; and 11% of the articles were applied neurodevelopmental theory. Only one article was used a combination approach of normative functional skill and general abilities. These papers were mainly focused on the movement characteristics of children with DCD and the intervention effect of exercise or sports programs. Conclusion : Most of the reviewed studies investigated the movement characteristics of DCD or explore the effectiveness of particular intervention programs. In the future, it would be useful to investigate the feasibility of different assessment tools and to establish the effectiveness of various interventions used in rehabilitation for better motor performance in children with DCD.