• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.360-365
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• 2003

In this paper, we have developed a general purpose motion controller using an FPGA(Field Programmable Gate Array). The multi-PID controllers on a single chip are implemented as a system-on-chip for multi-axis motion control. We also develop a PC GUI for an efficient interface control. Comparing with the commercial motion controller LM 629 it has multi-independent PID controllers so that it has several advantages such as space effectiveness, low cost and lower power consumption. In order to test the performance of the proposed controller, robot finger is controlled. The robot finger has three fingers with 2 joints each. Finger movements show that position tracking was very effective. Another experiment of balancing an inverted pendulum on a cart has been conducted to show the generality of the proposed FPGA PID controller. The controller has well maintained the balance of the pendulum.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.1
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• pp.73-80
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• 2004

We have developed a general purpose motion controller using an FPGA(Field Programmable Gate Array). The multi-PID controllers and GUI are implemented as a system-on-chip for multi-axis motion control. Comparing with the commercial motion controller LM 629, since it has multi-independent PID controllers, we have several advantages such as space effectiveness, low cost and lower power consumption. In order to test the performance of the proposed controller, motion of the robot hand is controlled. The robot hand has three fingers with 2 joints each. Finger movements show that tracking was very effective. Another experiment of balancing an inverted pendulum on a cart has been conducted to show the generality of the proposed FPGA PID controller. The controller has well maintained the balance of the pendulum.

• Tribology and Lubricants
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• v.13 no.2
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• pp.8-15
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• 1997

It is very difficult to express the state of a tested engine objectively concerning the malfunction, failure and wear of an engine. The general method of engine evaluation is to express evaluator's opinion for the engine state after testing. However, these methods is only subjective evaluation because test engineers, designers, and evaluators does not easily coincide in opinion. Therefore, in this article, the method of engine rating are introduced in order to represent the qualitative trends into quantitative value. The purpose of Engine Rating is to assign a quantified value to the tribology state of a tested engines. Originally, this Engine Rating method have been used to evaluate the performance of engine oil quantitavely. Using this method, we can predict the proper interval of engine oil change due to its objectivity. So, we can prevent the frequent change of engine oil and protect the environmental contamination. Furthermore, this method can be used to tell the general state of a tested engine after finishing engine durability tests. A single merit scale is used to evaluate numerically the state of cleanliness and the mechanical condition. Generally, a part which is absolutely clean or shows no wear, is rated merit 10. A part which is absolutely dirty or very worn, is rated merit 0.

• Journal of The Korean Astronomical Society
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• v.34 no.4
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• pp.191-201
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• 2001

My contribution to these proceedings summarizes a general overview on High Resolution Shock Capturing methods (HRSC) in the field of relativistic hydrodynamics with special emphasis on Riemann solvers. HRSC techniques achieve highly accurate numerical approximations (formally second order or better) in smooth regions of the flow, and capture the motion of unresolved steep gradients without creating spurious oscillations. In the first part I will show how these techniques have been extended to relativistic hydrodynamics, making it possible to explore some challenging astrophysical scenarios. I will review recent literature concerning the main properties of different special relativistic Riemann solvers, and discuss several 1D and 2D test problems which are commonly used to evaluate the performance of numerical methods in relativistic hydrodynamics. In the second part I will illustrate the use of HRSC methods in several astrophysical applications where special and general relativistic hydrodynamical processes play a crucial role.

• Journal of the Earthquake Engineering Society of Korea
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• v.22 no.4
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• pp.253-259
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• 2018

Structure behaviors resulting from an earthquake are experimentally simulated mainly through a shaking table test. As for large-scale structures, however, size effects over a miniature may make it difficult to assess actual behaviors properly. To address this problem, research on the hybrid simulation is being conducted actively. This method is to implement numerical analysis on framework members that affect the general behavior of the structure dominantly through an actual scale experiment and on the rest parts by applying the substructuring technique. However, existing studies on hybrid simulation focus mainly on Slow experimental methods, which are disadvantageous in that it is unable to assess behaviors close to the actual level if material properties change depending on the speed or the influence of inertial force is significant. The present study aims to establish a Real-time hybrid simulation system capable of excitation based on the actual time history and to verify its performance and applicability. The hybrid simulation system built up in this study utilizes the ATS Compensator system, CR integrator, etc. in order to make the target displacement the same with the measured displacement on the basis of MATLAB/Simulink. The target structure was a 2-span bridge and an RC pier to support it was produced as an experimental model in order for the shaking table test and Slow and Real-time hybrid simulations. Behaviors that result from the earthquake of El Centro were examined, and the results were analyzed comparatively. In comparison with the results of the shaking table test, the Real-time hybrid simulation produced more similar maximum displacement and vibration behaviors than the Slow hybrid simulation. Hence, it is thought that the Real-time hybrid simulation proposed in this study can be utilized usefully in seismic capacity assessment of structural systems such as RC pier that are highly non-linear and time-dependent.

• Journal of the Korean Society of Physical Medicine
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• v.13 no.2
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• pp.115-127
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• 2018

PURPOSE: This study aimed to investigate the effect of empowerment on job satisfaction for physical therapists in general hospitals. METHODS: A total of 297 physical therapists working in general hospitals throughout the country participated in the study survey using self-administered questionnaires. The questionnaires comprised three major parts, i.e., questions about general characteristics, empowerment, and job satisfaction, which were rated using a 5-point Likert scale. Statistical analysis was performed to analyze the frequency and percentage of participants, and the independent t-test and analysis of variance were performed to determine the difference in job satisfaction according to the general characteristics. Stepwise multiple regression was used to evaluate the factors that affect job satisfaction. RESULTS: The average of total empowerment, including two subordinate concepts, was 3.29 points, that of psychological empowerment was 3.53 points, and that of structural empowerment was 3.05 points. The average job satisfaction of the participants was 3.43 points, and it showed a significant difference in age, overall work experience, current work experience, position, annual salary, and daily work hours. Moreover, job satisfaction increased as the subordinate factors for empowerment, i.e., support, resources, chance, and competence, increased. Other factors that affect job satisfaction were daily work hours, number of colleagues, type of work, annual salary, and therapeutic assistance. CONCLUSION: This study demonstrated that job satisfaction of physical therapists working in general hospitals was related to empowerment, thereby indicating that job satisfaction and work performance can be increased by improving their empowerment.

• Journal of East-West Nursing Research
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• v.26 no.2
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• pp.139-148
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• 2020

Purpose: This study was conducted to determine the effects of self-leadership, professional self-concept, and positive psychological capital on the performance of operating room nurses. Methods: The participants were 148 operating room nurses with more than a year of experience in one of the general hospitals in Seoul, Korea. Data were collected from 18 to 29 November 2019 and were analyzed by descriptive statistic methods, t-test, ANOVA, Pearson's correlation coefficient analysis, and multiple regression analysis using the SPSS/WIN 21.0 program. Results: The self-leadership, professional self-concept, and positive psychological capital of operating room nurses showed a positive correlation with nursing performance. The performance of operating room nurses was the most affected by professional self-concept (β=.32, p=.002), followed by operating room career (β=.22, p=.037) and positive psychological capital (β=.20, p=.039), which together accounted for a nursing performance of up to 42.9% (F=12.06, p<.001). Conclusion: Based on these findings, it is necessary to develop education and intervention programs to enhance the operating room nurses' professional self-concept and positive psychological capital.

• Journal of Korean Academy of Nursing Administration
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• v.22 no.3
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• pp.251-259
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• 2016

Purpose: The purpose of this study was to examine the effects of workplace spirituality and organizational citizenship behavior on nurses' performance of nursing. Methods: This study was done over a 6 month period, with 395 nurses participants from 5 different general hospitals with 400 beds in 4 regions of Korea. Data were gathered using self-reported questionnaires from July 23 to August 21, 2015. Data were analyzed using descriptive statistics, independent t-test, one way ANOVA, Pearson correlation coefficients, and multiple regression analyses with IBM SPSS 21.0 program. Results: Nursing performance showed positive correlations with workplace spirituality and organizational citizenship behavior. The significant predictors of the nursing performance by nurses were a master's degree or higher (${\beta}=.26$), civic virtue (${\beta}=.19$), courtesy (${\beta}=.12$), 40 years of age or older (${\beta}=.09$), a sense of empathy (${\beta}=.07$), and a bachelor's degree in nursing (${\beta}=.06$). These variables explained 39.2% of the variance in nursing performance by nurses. Conclusion: Based on the outcomes of this study, there is a need to develop intervention programs that can inspire nurse to show spontaneous organizational citizenship behavior, and enhance their workplace spirituality. Related variables including academic credentials should also be taken into account.

• Research in Community and Public Health Nursing
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• v.31 no.1
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• pp.34-42
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• 2020

Purpose: The objective of this study was to identify whether spirituality mediates the relationship between empathy and elderly care performance among Long Term Care (LTC) hospitals nurses in Korea. Methods: The data collection was performed July 1st to August 31th, 2018. Participants were 119 nurses from three long-term care hospitals in Korea. Self-reported questionnaires were administered to assess general characteristics, empathy, spirituality and elderly care performance. The data were analyzed using descriptive statistics, t-test, one-way ANOVA, Pearson's correlation coefficients, and three-stage simple and multiple regression analysis as proposed by Baron and Kenny. Results: The level of elderly care performance of participants was significantly different based on age (F=3.92, p=.010) and nurse's position (t=-2.18, p=.031). Spirituality had a significant mediating effect on the relationship between empathy and elderly care performance (Z=3.64, p<.001). Conclusion: As spirituality completely mediates the relationship between empathy and elderly care performance, it is necessary to develop a nursing education program that applies spirituality and empathy and supports religious activities at an institutional level.

• Korean Journal of Human Ecology
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• v.15 no.1
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• pp.45-53
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• 2006

The goal of this study is to examine the relationship between efficacy belief and role performance of childcare teachers, and also to utilize the results as the basic data for teacher education. The subjects were 205 teachers at 48 childcare centers located in Jeonlabuk-do area. The instruments employed included efficacy belief, teachers' role performance, experiences, and age. The data were analyzed by t-test, Pearson correlation, and Regression Analysis. The results of this study are as follows: First, the role of child carer was the vest performance through childcare teachers' role. Second, the role of instructor, counselor, researcher, and others was significantly different among the types of childcare institution. Third, the social position of ability and personal teaching efficacy belief were correlated positively with teachers' experience. The activeness, the social position of ability, general teaching efficacy belief, personal teaching efficacy belief, and the role of child carer, instructor, counselor, researcher, and others were correlated positively with teachers' age. Fourth, the role of child carer, instructor, counselor, researcher, and others was correlated positively with the activeness and the social position of ability, whereas it was correlated negatively with failure anxiety. Lastly, the activeness was the most powerful variable influencing teachers' role performance.