• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1489-1491
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• 2005

This paper proposes a design method using PQR instantaneous power theory on the active power filter, unbalanced nonlinear load condition and unbalanced source voltage condition in three-phase four-wire systems. For reduction of current harmonics and neutral current, the control structure including repetitive controller is proposed and controller gain is designed. For fully-digital implementation, ramp comparison PWM method was adopted. Simulation results verify good performance of the proposed current control strategy on the shunt APFs.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1275-1278
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• 1997

Cutting process has been automated by progress of CNC and CAD/CAM, but polishing process has been depended on only experiential knowledge of expert. To automate the polishing pricess polishing robot with 2 degrees of freedom which is attached to a machining center with 3 degrees of freedom has been developed. this automatic polishing robot is able to keep the polishing tool normal on the curved surface of die to improve a performance of polishing. Polishing task for a curved surface die demands repetitive operation and high precision, but conventional control algorithm can not cope with the problem of disturbance such as a change of load. In this research, we develop robust controller using real time sliding mode algorithm. To obtain gain parameters of sliding model control input, the signal compression method is used to identify polishing robot system. To obtain an effect of 5 degrees of freedom motion, 5 axes NC data for polishing are divided into data of two types for 3 axis machining center and 2 axis polishing are divided into data of two types for 3 axis machining center and 2 axis polishing robot. To find an efficient polishing condition to obtain high quality, various experiments are carried out.

• 기본간호학회지
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• 제24권3호
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• pp.219-229
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• 2017

Purpose: The aim of this study was to examine the relationship between handwashing knowledge and handwashing compliance in nursing students and to identify the moderation and mediation effects of self-efficacy and perceived behavioral control on the relationship. Methods: The participants were 172 nursing college students who completed the self-report measures. Data were analyzed using t-test, ANOVA, and Pearson correlation coefficient, Multiple regression analysis was used to test moderation and mediation effects. Results: The score for knowledge of handwashing was higher in participants who had completed fundamentals of nursing practicum (t=-6.54, p<.001) and the score for compliance with handwashing was higher in participants who had completed clinical practicum (t=-3.81, p<.001) or fundamentals of nursing practicum (t=-5.97, p<.001). Self-efficacy showed a significant moderation effect (z=2.21, p=.027) but not a mediation effect while perceived behavioral control had a significant mediation effect but not a moderation effect on the relationship between knowledge of handwashing and compliance. Conclusion: Findings indicate that clinical practicum and fundamentals of nursing practicum were helpful to nursing students in acquiring knowledge and in practicing proper handwashing technique. These findings suggest that continuing and repetitive education programs on handwashing need to be enhanced and strategies to strengthen self-efficacy and perceived behavioral control need to be included in education programs.

• 로봇학회논문지
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• 제13권3호
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• pp.151-156
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• 2018

Military robots are expected to play an important role in the future battlefield, and will be actively engaged in dangerous, repetitive and difficult tasks. During the robots perform the tasks a human operator controls the robots in a supervisory way. The operator recognizes battlefield situations from remote robots through an interface of the operator control center, and controls them. In the meantime, operator workload, controller interface, robot automation level, and task complexity affect robot operability. In order to assess the robot operability, we have developed ROSim (Robot Operational Simulator) incorporating these operational factors. In this paper, we introduce the results of applying ROSim experimentally to the assessment of reconnaissance robot operability in a battle field. This experimental assessment shows three resulting measurements: operational control workload, operational control capability, mission success rate, and discuss its applicability to the defense robot research and development. It is expected that ROSim can contribute to the design of an operator control center and the design analysis of a human-robot team in the defense robot research and development.

• 여성건강간호학회지
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• 제10권4호
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• pp.291-300
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• 2004

Purpose: This study attempted to show the implications of obese female college students' weight control experiences and to use this as primary data for developing a nursing intervention. Method: The participants were 7 obese students who had tried losing weight at C College on Jeju Island. Their average age was 22 and BMI was $25.6kg/m^2$ on average. The data were collected from May 17th to July 6th 2004, and in-depth interviews were conducted with open-ended questions. Result: The analysis was conducted by Colaizzi's phenomenological method, and the analyzed results were categorized into 9 criteria, 22 theme clusters and 50 themes. The 9 criteria include withdrawal, desperation, self-restraint, relief, satisfaction, distraction, depression, regaining self-control and negligence of health. They tended to go through a weight gain loss cycle in a repetitive manner, and were faced with great physical and mental difficulties. In addition, they often went on a severely-strict diet without taking their health condition into consideration, which, in effect, causes various health problems. Conclusion: This study gives insights into the weight control experiences of obese female college students, and it shows developing more practical and effective nursing interventions are urgently needed.

• 한국기계기술학회지
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• 제13권3호
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• pp.7-16
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• 2011

This study proposes the compensation method for the mechanical deflection error of a SCARA robot. While most studies on the related subject have dealt with the development of a control algorithm for improvement of robot accuracy, this study presents the control method reflecting the mechanical deflection error which is predicted in advance. The deflection at the end of the gripper of SCARA robot is caused by the self-weights and payloads of Arm 1, Arm 2 and quill. If the deflection is constant even though robot's posture and payload vary, there may not be a big problem on robot accuracy because repetitive accuracy, that is relative accuracy, is more important than absolute accuracy in robot. The deflection in the end of the gripper varies as robot's posture and payload change. That's why the moments $M_x$, $M_y$ and $M_z$ working on every joint of a robot vary with robot's posture and payload size. This study suggests the compensation method which predicts the deflection in advance with the variations in robot's posture and payload using neural network. To do this, I chose the posture of robot and the payloads at random, found the deflections by the FEM analysis, and then on the basis of this data, made compensation possible by predicting deflections in advance successively with the variations in robot's posture and payload through neural network learning.

• 드라이브 ㆍ 컨트롤
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• 제19권4호
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• pp.110-116
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• 2022

Recently, various studies have been conducted to apply deep learning and AI to various fields of autonomous driving, such as recognition, sensor processing, decision-making, and control. This paper proposes a controller applicable to path following, static obstacle avoidance, and pedestrian avoidance situations by utilizing reinforcement learning in autonomous vehicles. For repetitive driving simulation, a reinforcement learning environment was constructed using virtual environments. After learning path following scenarios, we compared control performance with Pure-Pursuit controllers and Stanley controllers, which are widely used due to their good performance and simplicity. Based on the test case of the KNCAP test and assessment protocol, autonomous emergency steering scenarios and autonomous emergency braking scenarios were created and used for learning. Experimental results from zero collisions demonstrated that the reinforcement learning controller was successful in the stationary obstacle avoidance scenario and pedestrian collision scenario under a given condition.

• 대한물리의학회지
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• 제12권3호
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• pp.67-71
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• 2017

PURPOSE: Muscle fatigue is a cause to change proprioception. The purpose of this study was to investigate the effects of calf muscle fatigue and visual control on postural balance during single-legged standing in healthy adults. METHODS: Nineteen healthy adults (male) were participated in this study (mean age: 24.36 years; mean height: 171.32 cm; mean weight: 64.58 kg). The postural balance (sway length, sway area, sway velocity of COG displacement) was measured by Balance Trainer System (BT4) in before and after calf muscle fatigue feeling in single legged stance. In this study, repetitive single-legged heel rise test was used to induce fatigue of the calf muscle. Paired t- test was used to compare the postural balance between before and after calf muscle fatigue. Data of subjects were analyzed using SPSS 22.0 (SPSS Inc., Chicago, IL, USA). Level of significance was set to .05. RESULTS: The sway length, sway area, sway velocity of COG (center of gravity) displacement after calf muscle fatigue feeling was significantly increased compared to before calf muscle fatigue feeling during single leg standing both eye open and close conditions (p<.05). CONCLUSION: This study suggested that calf muscle fatigue feeling has affected on postural balance when standing one leg both eye open and close conditions and postural control was disturbed by muscle fatigue and visual feedback in single leg standing.

• The Journal of Korean Physical Therapy
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• 제17권2호
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• pp.67-87
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• 2005

Impaired sensorimotor function of the hand ipsilateral to a unilateral brain damage has been reported in a variety of motor task. however, it is still the controversial issue because of the difficulty of detection in clinical situation, patients' variability(time after onset, contralateral upper extremity severity, other cognitive functions including apraxia), and the performed various motor task. The purpose of this study is to determine the presence of ipsilateral motor deficit following unilateral brain damage in three different specific tasks(hand tapping, visual tracking and coin rotation) compared with healthy age-sex matched control group using the same hand and to investigate the lateralized motor control in each hemispheric function. Findings revealed that stroke patients with unilateral brain damage experienced difficulties with rapid-simple repetitive movement, visuomotor coordination, complex sequencing movement on ipsilateral side. Also, Comparison of the left-hemispheric stroke groups and the right-hemispheric stroke groups revealed that patients with a left-hemisphere damage tended to be more variable in performing all of the three tasks. These results show that stroke patient with left hemisphere damage has more ipsilateral motor deficit, and the left hemisphere contributes to the processing of motor control that necessary for the executing actions with ipsilateral hand.

• 성인간호학회지
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• 제28권1호
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• pp.53-60
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• 2016

Purpose: This study was to compare the effects of early ambulation to usual care of late ambulation in patients with transarterial chemoembolization on back pain, discomfort, and puncture site complications. Methods: A nonequivalent control pretest-posttest design was used. Total 40 patients were recruited from a gastrointestinal unit of an urban general hospital in Seoul, South Korea. The experimental group began to ambulate after 4 hours of bed rest with a compression bandage after receiving transarterial chemoembolization. The control group stayed in bed with a compression bandage overnight. Results: Back pain was not significantly different between the two group. The experimental group reported significantly lower discomfort than the control group. There was no incidence of bleeding complications on puncture site between two groups. Conclusion: The results of this study showed that early ambulation with four hours of bed rest after femoral sheet removal did not cause bleeding complications compared to the usual care and even decreased patients' level of discomfort due to bed rest. Repetitive research on the effect of short bed rest is warranted for its clinical utilization.